BeotiVf:-!-) nv osT! j u n Q 6 1986

# soml N U R E G / C R - - 3 7 7 0

TI86 011205

NUREG/CR-3770ORNL/TM-9176

OAK RIDGENATIONALLABORATORY Preliminary Development of an

Integrated Approach to the Evaluation of Pressurized

Thermal Shock as Applied to the Oconee Unit 1 Nuclear Power Plant

Prepared for the Division of Risk Analysis and Operations Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission

Under Interagency Agreement DOE 40-550-75

OPERATED BYM A R TIN M A R IE H A ENERGY S Y S T E M S , IN C . FOR THE UNITED STATES D EPA RTM EN T OF .ENERGY

0T' ’■'pfBunoN OF !s u N im rfl®

NOTICEThis report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.

DISCLAIM ER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi­bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer­ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom­mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Available from

Superintendent of Documents U.S. Government Printing Office

Post Office Box 37082 Washington, D.C. 20013-7982

and

National Technical Information Service Springfield, VA 22161

'w'.

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

DISCLAIM ER

Portions of this document may be illegible in electronic image

products. Images are produced from the best available

original document.

NOTICE

T h is report contains in fo rm a tio n o f a p re lim in a ry n a tu re a n d was p re p a re d p rim arily for in te rn a l use a t th e o r ig in a tin g in sta lla tio n . I t is subject to revision o r co rrec tio n an d th e re fo re does not rep re s e n t a fina l report. I t is passed to th e rec ip ien t in confidence a n d should not be a b s tra c te d o r fu r th e r d isclosed w ith o u t th e a p p ro v a l of th e o rig in a tin g in sta lla tio n o r U S D O E O ffic e of S c ie n tif ic and T echnical In fo rm a tio n , O a k R id g e , T N 37830. NUREG/CR-3770

ORNL/TM-9176 Distribution Category RG

Instrumentation and Controls Division

PRELIMINARY OEVELOFMENT OF AN INTEGRATED APPROACH TO THE EVALUATION OF PRESSURIZED THERMAL SHOCK AS APPLIED

TO THE O C W E E UNIT 1 NUCLEAR POWER PLANT

T. J. Burns*R. D. ChevertonG. F. Flanagan*J . D. White D. G. Ball+ ^L . B. Lamoni ca"R. Olsoni

Technical Monitor: Carl Johnson, NRC

MASe

Manuscript Completed: Date Published:

April 1984 May 1986

•Engineering Physics and Mathematics Division. j^Computing and Telecommunications Division. ^Science Applications International Corporation.

Prepared for the Division of Risk Analysis and Operations

Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission

Under DOE Interagency Agreement 40-550-75 NRC FIN No. B0468

Prepared by the Oak Ridge National Laboratory Oak Ridge, Tennessee 3 7831

operated by Martin Marietta Energy Systems, Inc.

for the U.S. DEPARTMENT OF ENERGY

under Contract No. DE-AC05-840R21400

P OF 7W3 OOCUMfJIlT IS UNUMIT9

PREFACE

This report snnmarizes the results of a plant-specific evaluation of pres­

surized thermal shock (PTS) based on the Oconee Unit 1 Nuclear Power Plant.

This evaluation was the first of three undertaken by ORNL for the Nuclear

Regulatory Commission. (The other two evaluations were for Calvert Cliffs

Unit 1 and H. B. Robinson Unit 2.)

Assessment of the PTS risk to the Oconee plant required the development of

a specialized methodology combining various elements of risk analysis,

thermal hydraulics, and fracture mechanics. Moreover, since the PTS

evaluation was carried out in terms of an overall risk analysis framework,

the supporting thermal-hydraulic and fracture-mechanics analyses were

required to be probabilistic in nature. The integration of these diverse

disciplines into a coherent whole was a major task of this first study. In

particular, the development of system state tree methodology, a probabilis­

tic fracture-mechanics model, a simplified thermal-hydraulics approach, and

sensitivity and uncertainty analyses as applied to PTS were all introduced

in the Oconee analysis (and later refined in the evaluations for Calvert

Cliffs and H. B. Robinson).

Development of a new methodology such as that used for the PTS evaluation

is evolutionary; that is, initially selected procedures may prove to be not

the optimum ones. The philosophy followed on the three PTS pilot studies

was to apply the lessons learned from each study to improve the next study,

and not go back and reanalyze the first study with improved methods. Since

this particular study represented the first attempt to combine both

ill

thermal-hydraulic and fracture-mechanics analysis into an integrated risk

analysis methodology, it is not surprising that the results of the

thermal-hydraulics and fracture-mechanics calculations are not as closely

integrated with each other and with the event-tree analyses as in the sub­

sequent two studies, as described below. As a result, this report should

be viewed as the documentation of the initial attempt to address the com­

plex phenomenon termed "pressurized thermal shock" as a coherent whole,

with the Oconee study serving as the springboard for the Calvert Cliffs and

H. B. Robinson studies in which the methodology was refined and improved.

Several examples of the evolution of the methodology can be given. One is

the selection of the cutoff frequency used to *^rune" the event trees. For

the Oconee Unit 1 study, a frequency value of 1 x 10~® events per reactor

year (1.0E-06/R7) was initially utilized, and all sequences falling below

this value were combined to yield a residual risk component. Using a value

of l.OE-06 resulted in the residual component dominating the overall risk

measure. Although an attempt to analyze some of the residual sequences was

performed (and is incorporated in this report), it is apparent that a smal­

ler value for the cutoff frequency is more appropriate. Therefore, a value

of l.OE-07 was utilized for the Calvert Cliffs and H. B. Robinson studies.

Another example of improvement in methodology is the calculation of the

likelihood of an individual sequence driving a crack through the wall. Due

to the potential initiation of PTS transients via secondary side upsets

(e.g., overcooling transients), much of the thermal-hydraulic efforts per­

taining to this study involved the detailed modeling of the secondary side

of the nuclear power plants studied. In fact, it is believed that this

iv

study marked the first large-scale application of the computer codes TRAC

and RELAP to the secondary side of nuclear steam supply systems. One of

the problems of this initial study was that the coolant temperature during

a postulated event sequence was calculated in detail only during the ini­

tial (rapidly moving) phase of the transient and the temperature/pressure

descriptions were then extrapolated to longer times (roughly two hours).

Hence, for those transients in which this procedure was utilized to deter­

mine the full two-hour transient, the longer term pressures and tempera­

tures are subject to an additional amount of uncertainty. Also a large

number of possible sequences were "binned" into relatively few categories

of thermal-hydraulic transients for estimating the conditional probability

of a through-the-wall crack. In general, this led to conservative estima­

tes of vessel failure for each transient considered. In the Calvert Cliffs

and H. B. Robinson studies, thermal-hydraulic and fracture-mechanics calcu­

lations were performed for a higher percentage of the transients and there

was less reliance on extrapolations.

Owing to the limited number of thermal-hydraulic transients available

(either calculated or estimated), the influence of the reactor operator as

modeled in the Oconee study by Operator Action Trees was often reduced to a

single action (e.g., isolating the feedwater systems), even though it was

understood that other actions would also influence the course of a given

transient. Due to the limitations, only the operator action regarded as

most significant was incorporated into the analysis. In the other two stu­

dies an alternate method (i.e.. influence diagrams) of accounting for the

operator during the course of a PTS transient was employed.

As part of the methodology development of this study, the sensitivity and

uncertainty analyses were approached from an analytical standpoint. The

use of analytical procedures to assess the uncertainty in the results for

the Oconee study necessitated the use of symmetric distributions to

represent the various components of the overall uncertainty (that is, the

uncertainty arising from the event tree analyses, the thermal-hydraulic

analyses, etc.). In retrospect, the assumption of symmetric uncertainty

distributions was not appropriate for many of the parameters addressed,

such as the coolant temperatures reached at the end of a two-hour tran­

sient. However, since the analytical procedure chosen for the Oconee sen­

sitivity and uncertainty analyses required the use of such distributions,

the (probably conservative) assumption that the actual distributions could

be approximated by symmetric ones was made. The methodology utilized in

the Calvert Cliffs and H. B. Robinson studies was changed to a stochastic

or Monte Carlo procedure.

In conclusion, it is the authors' and NRC program monitor's opinion that

this report is important because it presents the basic analysis methodology

that was later finalized in the later two studies. In addition, it provi­

des insight with respect to the PTS issue for the Oconee Unit 1 plant.

However, the reader should be cautioned in the use of the absolute numbers

presented in the report.

Authcir

NRC Technical Monitor

VI

CONTENTS

Page

ABSTRACT...................................................... xv

1.0 INTRODUCTION....................................... 1.1

1.1 Background........................................ 1.1

1.2 Overall Objectives of PTS Studies.................. 1.3

1.3 Limitations of the S t u d i e s ........................ 1.4

1.4 PTS Analysis for Oconee, Unit I .................... 1.4

1.5 Description of this R e p o r t ........................ 1.6

REFERENCES.................................................... 1,8

2.0 PLANT DESIGNS AND OPERATIONS PERTINENT TO PRESSURIZEDTHERMAL SHOCK ............................................ 2.1

2.1 Introduction...................................... 2.1

2.2 Systems............................................ 2.1

2.2.1 Reactor Cooling Systems (RCS) ................ 2.1

2.2.2 Feedwater and Steam Systems................. 2.14

2.2.3 Control Systems............................. 2.23

2.2.4 Support Systems............................. 2.32

2.3 Operations........................................ 2.35

2.3.1 Reactor T r i p .............................. 2.36

2.3.2 LOCA Events................................ 2.39

2.3.3 Secondary-Side Overcooling Events .......... 2.40

REFERENCES.................................................... 2.43

3.0 EVENT SEQUENCE ANALYSIS ................................... 3.1

3.1 Introduction...................................... 3.1

3.2 Methodology........................................ 3.2

Vll

Page

3.3 Construction of the Oconee-1 System State Trees . . . . 3.7

3.3.1 Secondary Pressure Control System State Trees . 3.7

3.3.2 Feedwater System State Trees ................ 3.12

3.3.3 Primary Loop Coolant Flow System State Trees . 3.22

3.3.4 Primary Pressure Control System State Tree . . 3.31

3.4 Quantification of the Functional System State Trees . . 3.35

3.4.1 Quantification of the Secondary Pressure-Control System State Tree .................... 3.38

3.4.2 Quantification of the Feedwater System StateTrees.......................................... 3.41

3.4.3 Probability Modifications Required for Off-Normal Situations.............................. 3.47

3.4.4 Quantification of the Primary Loop ECCS SystemState T r e e .................................... 3.51

3.5 Transient Categorization ............................ 3.57

3.5.1 Secondary Pressure-Control System (SPC) . . . . 3.57

3.5.2 Feedwater System (FWS) ...................... 3.59

3.5.3 Emergency Core Cooling System (ECCS) ......... 3.60

3.5.4 Primary Pressure Control System (PPC) ........ 3.60

3.6 Initiator-Specific System State Tree Construction . . . 3.61

3.6.1 Reactor/Turbine T r i p ........................... 3.63

3.6.2 Excessive MFW: Initial Conditions andConditioning Event Assumptions .............. 3.71

3.6.3 Large Steam Line Break (LSLB): InitialConditions and Conditioning Event Assumptions . 3.72

3.6.4 Small Steam Line B r e a k ......................... 3.73

3.6.5 Loss of MFW (LOMFW): Initial Conditions andConditioning Event Assumptions 3.74

Vlll

Page

3.6.6 Small-Break LOCA 1: Initial Conditions andConditioning Event Assumptions .............. 3.74

3.6.7 Small-Break LOCA 2: Initial Conditions andConditioning Event Assumptions .............. 3.75

3.6.8 Inadvertent Safety Injection (SI): InitialConditions and Conditioning Event Assumptions 3.76

3.6.9 Categorization of Initiator-SpecificAsymptotic Transients ...................... 3.76

3.7 Effect of Operator Actions .......................... 3.77

4.0 THERMAL-HYDRAULIC EVALUATION .............................. 4.1

4.1 Introduction........................................ 4.1

4.2 Detailed Thermal-Hydraulic Models .................. 4.6

4.2.1 RELAF5 Model Description .................... 4.6

4.2.2 TRAC Model Description...................... 4.18

4.3 Results of Detailed Calculations .................... 4.28

4.3.1 RELAP5 Calculations ........................ 4.28

4.3.2 TRAC Calculations.......................... 4.64

4.4 Evaluation of Flow Stratification Effects .......... 4.101

4.5 Extrapolated Sequences .............................. 4.107

4.5.1 Methodology................................ 4.107

4.5.2 Turbine Bypass Valve Failures at Full Power . 4.110

4.5.3 Turbine Bypass Valve Failures at Hot Standby . 4.113

4.5.4 PORV-Sized LOCA C a s e s ...................... 4.118

4.5.5 Feedwater Overfeed Cases .................... 4.126

4.5.6 Steam Generator Tube Rupture ................ 4.131

4.5.7 Main Steam Line Break C a s e s ............ .. . 4.131

4.6 Summary of Thermal-Hydraulic Evaluations ............ 4.138

REFERENCES.................................................... 4.143

IX

Page

5.0 CONDITIONAL PROBABILITY OF VESSEL FAILURE .................. 5.1

5.1 Introduction........................................ 5.1

5.2 Description of Basic P r o b l e m ........................ 5.1

5.3 Calculational Models ................................ 5.6

5.3.1 Fracture-Mechanics Model .................... 5.6

5.3.2 Stress Analysis Model ........................ 5.14

5.3.3 Thermal Analysis Model ...................... 5.16

5.3.4 Probabilistic Analysis Model ................ 5.17

5.4 Flaw-Related Data for the Oconee-1 Reactor PressureV e s s e l ................................................ 5.27

5.5 Results of Analysis.....................................5.31

5.5.1 Types of Analyses Conducted .................. 5.31

5.5.2 Conditional Probability of Vessel Failure . . . 5.31

5.5.3 Sensitivity Analysis ........................ 5.42

5.5.4 Effect of Including W P S .........................5.43

5.5.5 Effect of Proposed Remedial Measures on P(F/E) 5.45

REFERENCES...................................................... 5.50

6.0 PTS INTEGRATED RISK AND POTENTIAL MITIGATION MEASURES . . . . 6.1

6.1 Introduction.........................................6.1

6.2 Risk Integration.................................... 6.1

6.3 Potential Mitigation Measures ........................ 6.11

6.3.1 Limit Primary System Repressurization ........ 6.11

6.3.2 Effect of High SG Level Trip System............. 6.12

6.3.3 Neutron Fluence Rate Reduction................... 6.13

6.3.4 Effect of HPl Heating........................... 6.13

X

Page

6.3.5 In-Service Inspection ........................ 6.18

6.3.6 Vessel Annealing ............................ 6.18

6.3.7 Operator Training ............................ 6.19

7.0 SENSITIVITY AND UNCERTAINTY ANALYSES ...................... 7.1

7.1 Introduction........................................ 7.1

7.2 Uncertainty Analysis ................................ 7.1

7.3 Discussion of Assumptions .......................... 7.3

7.4 Transient Frequency Uncertainties .................... 7.5

7.5 Branch Point Uncertainties .......................... 7.6

7.6 Residual Branch Point Analysis ....................... 7.8

7.7 Human Factor Analysis ................................ 7.10

7.8 Fracture Mechanics Analysis.......................... 7.10

7.9 Thermal-Hydraulic Analysis .......................... 7.11

7.10 Summary and Discussion.................................7.11

8.0 CONCLUSIONS AND RECOMMENDATIONS.............................. 8.1

8.1 Introduction........................................ 8.1

8.2 Conclusions from the Oconee-1 Study....................8.1

8.2.1 Oconee-1 System Features and Proposed SystemChanges...................................... 8.1

8.2.2 Accident Sequence Analysis .................. 8.3

8.2.3 Fracture Mechanics Analysis .................. 8.4

8.2.4 Uncertainty and Sensitivity Analysis ........ 8.5

8.2.5 General Conclusions .......................... 8.6

8.3 Areas Requiring Further Study and Development ......... 8.7

8.3.1 Human Reliability ............................ 8.7

XI

Page

8.3.2 System Interactions.......................... 8.7

8.3.3 External Events.............................. 8.8

8.3.4 Flooding.................................... 8.8

8.3.5 Thermal-Hydraulic Modeling .................. 8.8

8.3.6 Decay Heat Assumptions...................... 8.9

8.3.7 Duration of Calculated Transients ............ 8.9

8.4 Summary................................................. 8.10

APPENDIX A - EVENT TREES........................................ A.l

A.l Sequences by Identification Number and Frequency,System State Tree Branch Points ...................... A.2

A.2 Sequences Summed by System State Category ........... A.24

A.3 General Table of Vessel Through-Wall Crack FrequencyResults.............................................. A.30

APPENDIX B - EVENT TREE QUANTIFICATION .......................... B.l

B.l Introduction.........................................B.l

B.2 System-Related Probability Values ..................... B.2

B.3 Human Error-Related Probability Values ............... B.2

B.4 Thermal-Hydraulic-Related Probability Values ......... B.IO

APPENDIX C - ESTIMATION OF PRESSURE, TEMPERATURE, AND HEATTRANSFER COEFFICIENT ...................................... C.l

C.l Introduction.........................................C.l

C.2 Methodology...........................................C.3

C.2.1 General Approach ............................. C.3

C.2.2 Sequence Grouping ............................. C.6

C.2.3 Cooldown M o d e l ...............................C.6

C.3 Main Steam Line Break................................... C.16

C.3.1 MSLBl........................................... C.18

Xll

Page

C.3.2 MSLB2..........................................C.25

C.3.3 MSLB3..........................................C.26

C.3.4 MSLB4..........................................C.28

C.3.5 MSLB5..........................................C.34

C.3.6 MSLB6..........................................C.37

C.3.7 MSLB7..........................................C.42

C.4 Turbine Bypass Failures at Full Power ............... C.43

C.4.1 ORNL-Defined TBV Cases (19 Total)..............C.43

C.4.2 Group 1 — Cases TBVl, TBV2, and T B V 9 .... C.49

C.4.3 Group 2 — Cases TBV3 and T B V 5 .......... C.54

C.4.4 Group 3 — Cases TBV4 and T B V 6 .......... C. )5

C.4.5 Group 4 — Case T B V 7 .................... C.58

C.4.6 Group 5 — Cases TBV8 and TBV16 . . . . . . . . C.63

C.4.7 Group 6 — Cases TBVIO, TBV13, and TBV15 . . . C.66

C.4.8 Group 7 — Case TBV12.................... C.69

C.4.9 Group 8 — Case TBVll.................... C.72

C.4.10 Group 9 -- Case TBV17.................... C.75

C.4.11 Group 10 — Cases TBV 18 and TBV 1 9 ............C.75

C.5 Turbine Bypass Valve Failures in Hot Standby ....... C.81

C.5.1 Basis..........................................C.81

C.5.2 Departures from B a s i s ........................C.81

C.5.3 Applicable Data from Other C a s e s ..............C.83

C.5.4 Extrapolation Assumptions, Procedures, andResults........................................ C.83

C.6 PORV-Sized LOCA Cases.................................. C.95

C.6.1 ORNL-Defined PORV-Sized LOCAs ............... C.95

xiix

Page

C.6.2 Group 1 -- Cases SBLOCAl and SBL0CA7........ C.98

C.6.3 Group 2 — Cases SBL0CA2, SBL0CA4, and SBL0CA8 C.lOl

C.6.4 Group 3 — SBL0CA3 and SBL0CA9.............. C.104

C.6.5 Group 4 — Case S B L 0 C A 5 .................... C.107

C.6.6 Group 5 — Case S B L 0 C A 6 .................... C.lll

C.l Feedwater Transient Cases ......................... C.115

C.7.1 ORNL-Defined Feedwater Transient Cases . . . . C.115

C.l.2 Cases FWl and F W 2 .......................... C.117

C.7.3 Case F W 3 .................................... C.118

C.7.4 Case F W 4 .................................... C.124

C.l.5 Case F W S ........................................... C.124

C.7.6 Case F W 6 .................................... C.127

C.7.7 Case F W 7 .................................... C.133

C.8 Steam Generator Tube Rupture....................... C.137

APPENDIX D - CONTRIBUTION TO P(F/E) OF FLAWS IN THE CIRCUMFERENTIALWELDS AND THE BASE MATERIAL.............................. D.I

REFERENCES.................................................... D.3

APPENDIX E - COMPILATION OF RESULTS OF OCNONEE-I PROBABILISTICFRACTURE-MECHANICS ANALYSIS .............................. E.I

APPENDIX F - ALTERNATIVE APPROACH TO SEQUENCE ASSIGNMENT........ F.I

APPENDIX G - RESPONSE TO UTILITY COMMENTS ..................... G.I

X I V

ABSTRACT

An evaluation of the risk to the Oconee-1 nuclear plant due to pressurized

thermal shock (PTS) has been completed by Oak Ridge National Laboratory

(ORNL). This evaluation was part of a Nuclear Regulatory Commission (NRC)

program designed to study the PTS risk to three nuclear plants: Oconee-1,

a Babcock and Wilcox reactor plant owned and operated by Duke Power Com­

pany; Calvert Cliffs-1, a Combustion Engineering reactor plant owned and

operated by Baltimore Gas and Electric Company; and H. B. Robinson-2, a

Westinghouse reactor plant owned and operated by Carolina Power and Light

Company. Studies of Calvert Cliffs—1 and H. B. Robinson-2 are still

underway.

The specific objectives of the Oconee-1 study were to: (1) provide a best

estimate of the probability of a through-the-wall crack (TWO occurring in

the reactor pressure vessel as a result of PTS; (2) determine dominant

accident sequences, plant features, operator and control actions and uncer­

tainty in the PTS risk; and (3) evaluate effectiveness of potential correc­

tive measures. To perform the studies, (®NL constructed millions of

hypothetical overcooling events (using computer-generated event trees) and

then estimated both the consequences and the probabilities of occurrence

for each of these events. A screening frequency of 10“^ per reactor year

was used to screen out those event tree branches (scenarios) whose frequen­

cies were below that value. All of the remaining scenarios were considered

explicitly. The scenarios initially screened out were not discarded but

rather were included in a residual category, and their probability contri­

butions were included in the study. Detailed thermal-hydraulic (T-H)

X V

analyses were performed on a few of the scenarios by Los Alamos National

Laboratory and Idaho National Engineering Laboratory and these were

reviewed by Brookhayen National Laboratory. For some transients, downcomer

mixing calculations were performed by Purdue University. Thermal-hydraulic

consequences of all remaining transients (including as one group all those

in the residual) were estimated by Science Applications, Inc. For all

transients, probabilistic fracture-mechanics calculations were performed by

ORNL. The results of all these analyses were integrated by ORNL to predict

the probability of TWC for Oconee-1.

Our best estimate of the frequency of a TWC at Oconee-1 due to PIS at 32

EFPY was 4.5 X 10~6/reactor year. However, an uncertainty analysis perfor­

med by ORNL for this best-estimate frequency indicates that a factor of

about 100 is an appropriate 95% confidence interval, assuming a log-normal

uncertainty distribution. Steamline breaks were the most significant con­

tributors to the TWC risk for the t3rpes of sequences considered. Uncer­

tainty in downcomer temperatures was the most important contributor to the

overall uncertainty in the risk. The most important plant features which

were determined to reduce PTS risk at Oconee-1 were: (1) internal vent val­

ves and (2) feedwater pump trip on high steam generator level. The most

iaqportant operator action for negating PTS was the isolation of a steam

generator during a steamline break.

Minimal systems interactions were considered in this study and no external

events (fire, floods, seismic events) were considered.

XVI

1. INTRODUCTION

I. D. White, Oak Ridge National Laboratory

1.1. Background

Before the late 1970s it vas postulated that the most severe thermal shock

a pressurized-vater reactor vessel would be required to withstand would

occur during a large-break loss-of-coolant accident (LOCA). In this type

of overcooling transient, room-temperature emergency core coolant would

flood the reactor vessel within a few minutes and rapidly cool the vessel

wall. The resulting temperature difference across the wall would cause

thermal stresses, with the inside surface of the wall in tension. However,

the addition of pressure stresses to the thermal stresses was not con­

sidered, since it was expected that during a large-break LOCA the system

would remain at low pressure.

In 1978, the occurrence of a non—LOCA—tj^pe event at the Rancho Seco Nuclear

Power Plant in California showed that during some types of overcooling

transients the rapid cooldown could be accompanied by repressurization of

the primary system, ^ i c h would compound the effects of the thermal

stresses. As long as the fracture resistance of the reactor vessel remains

relatively high, such transients are not expected to cause the reactor

vessel to fail. However, after the fracture toughness of the vessel is

gradually reduced by neutron irradiation, severe pressurized thermal shock

(PTS) might cause a small flaw already existing near the inner surface of

1.1

the wall to propagate throngh the wall. Depending on the progression of

the accident, such a through-the-wa11 crack (TWC) could lead to core mel­

ting.

Following the Rancho Seco incident, the Nuclear Regulatory Commission (NSC)

designated pressurized thermal shock as an unresolved safety issue (A-49),

and the effects of pressurized thermal shock at (^crating PWRs were

analyzed with input from the owner groups and from eight selected utili­ties. On the basis of these analyses, NRC concluded that no event having a

significant probability of occurring could cause a FWR vessel to fail today

or within the next few years. However, NRC projected that as FWR vessels

are irradiated, particularly those containing copper in their welds, a few

vessels could eventually become susceptible to pressurized thermal shock

(SECY-82-465, SECY-83-288, and SECY-83-443).

In order to address the PTS possibility, NRC published a proposed rule that

(1) establishes a screening criterion on the reference temperature for

nil-ductility transition (RTNDT), (2) requires licensees to accomplish

reasonably practicable flux reductions to avoid exceeding the screening

criterion, and (3) requires plants that cannot stay below the screening

criterion to submit a plant-specific safety analysis to determine what, if

any, modifications are necessary if continued operation beyond the screen­

ing limit is allowed.

In addition, NRC organized a PTS research project, described in part in

this report, to help confirm the technical bases for the proposed PTS rule

and to aid in the development of guidance for the licensee plant-specific

1.2

PTS analyses, as well as tlie development of acceptance criteria for pro­

posed corrective measures. The research project consisted of PTS pilot

analyses for three PWRs: Oconee Unit 1, designed by Babcock and Wilcox;

Calvert Cliffs Unit 1, designed by Combustion Engineering; and H. B. Robin­

son Unit 2, designed by Westinghouse. The study team consisted of Oak

Ridge National Laboratory (ORNL), Idaho National Engineering Laboratory

(INEL), Los Alamos National Laboratory (LANL), Brookhaven National Labora­

tory (BNL), and Purdue University, with the results being integrated by

ORNL. The results of the first of the three planned pilot analyses, that

for Oconee Unit 1, is described in this report. The second analysis, for

Calvert Cliffs Unit 1, and the third, for H. B. Robinson Unit 2, are

described in separate reports.

1.2. Overall Objectives of PTS Studies

The overall objectives of the PTS studies at ORNL are: (1) to provide for

each of the three plants an estimate of the probability of a crack propaga­

ting through the wall of a reactor pressure vessel due to pressurized ther­

mal shock, (2) to determine the dominant overcooling sequences, plant

features, and operator and control actions and the uncertainty in the plant

risk due to pressurized thermal shock; and (3) to evaluate the effec­

tiveness of potential corrective measures. (X^NL was also to determine what

parts of the studies might have generic applicability.

1.3

1.3. Limitations of the Studies

Determining the conseonences of a through-the-wall crack was not a part of

the program; that is, studies of the geometry of a through-the-wall crack,

missile formation, the means for cooling the core, the extent of radiation

releases, and risks to the public were not addressed. These consequences

are to be studied under other NRC-sponsored work.

Neither did the program consider the effects of external events, such as

earthquakes, fires, and floods (both external and internal to the contain­ment), and sabotage. ORNL suspects that the effect of excluding such

events is not serious because of (1) the low probabilities that the events

will occur and (2) the likelihood that failures of systems due to external

events would cause undercooling situations rather than overcooling situa­

tions.

1.4. PTS Analysis for Oconee Unit 1

This report describes the PTS analysis of Oconee Unit 1, a PWR designed by

Babcock and Wilcox (B&W). Xhe reactor is owned and operated by the Duke

Power Company.

The reactor coolant system of Oconee Unit 1 has two hot legs and four cold

legs and utilizes two B&W once-through steam generators. The PTS analysis

for the unit consisted of:

1.4

(1) gathering plant data,

(2) building event tree models and thermal-hydraulic models,

(3) quantifying frequencies of event tree end states,

(4) predicting thermal-hydraulic responses of the plant to the

events,

(5) calculating the conditional probability of a through-the-wall

crack (TWC) for each event,

(6) integrating steps 3 and 5 to produce an estimate of overall

through-the-wall crack frequency at Calvert Cliffs Unit 1 due to

all events considered,

(7) performing sensitivity and uncertainty analyses on the results,

and

(8) evaluating potential corrective measures.

In support of the program, Duke Power Canpany provided the research team

with copies of plant drawings, plant data and operating procedures for

Oconee Unit 1, Thermal-hydraulic analysis models were developed by Idaho

National ^gineering Laboratory (INEL), Los Alamos National Laboratory

(LANL), Science Applications Incorporated (SAI) under subcontract to ORNL,

and Purdue liiiversity under other NRC-funded programs supporting the ORNL

PTS studies.

1.5

The SAI models were used by OBNL to provide an early understanding of plant

behavior, which was useful in building event tree models. The models

developed by INEL and LANL, which became available later, were necessarily

very complicated and expensive to run, and because of funding limitations,

only a few overcooling scenarios (less than 20) could be calculated expli­

citly. The scenarios calculated were chosen carefully to provide a basis for estimating the results of the remaining thousands of potential

scenarios.

INEL and LANL calculations were reviewed by Brookhaven National Laboratory.

In addition, because the computer code used by INEL (the RQ,AP5 code) and

LANL (the TRAC code) could not perform detailed mixing calculations, addi­

tional thermal-hydraulic studies that included mixing were performed under

another NRC contract by Purdue University. These detailed analyses by

INEL, LANL and Purdue were then used by SAI as a basis for estimating the

Oconee Unit 1 thermal-hydraulic behavior during the remainder of the

hypothetical transients.

1.5. Description of This Report

This report presents the results of the specific study for Oconee Unit 1

and describes the methodology developed for performing the analysis. Chap­

ter 2 describes the plant's components and operational behavior character­

istics that are believed by (®NL to be pertinent to the PTS issue.

1.6

Hopefully, this chapter and the accompanying references could be used to

build other models of the unit. The reader is advised, however, that buil­

ding a model useful in PTS studies is a difficult process due to the many

complex systems interactions occurring in operational upsets and the model

may not be applicable to other types of transients.

Chapter 3 describes the h3rpothetical overcooling sequences considered in

the analysis. The methodology used to determine what sequences are possi­

ble and how frequencies for the sequences are estimated is discussed in

detail. An event tree approach was chosen; no fault trees were used in

this analysis.

Chapter 4 discusses the thermal-hydraulics models and summarizes the calcu­

lations from the INEL, LANL, SAI and Purdue analyses. From this chapter,

the reader can obtain a good understanding of how Oconee Ihiit 1 is

predicted to behave under hypothetical overcooling scenarios.

Chapter 5 describes the calculations of conditional TWC probabilities for

groups of thermal-hydraulic responses. This work, done at ORNL, utilized

probabilistic fracture-mechanics analytical methods in assessments of the

probability that cracks might propagate through the reactor vessel wall.

The chapter describes the vessel welds and their chemistries and gives

estimated fluences throughout the expected plant lifetime. The assumed

crack densities and distributions are also described.

The integration of the event sequences analysis, thermal-hydraulic analysis

and fracture-mechanics analysis to produce an overall best estimate of PTS

1.7

risk at Oconee Unit 1 is described in Chapter 6. In this chapter the dom­

inant contributions to the risk and effects of potential corrective

measures are discussed. Although a need for corrective measures at Oconee

Unit 1 has not been established, the effects of corrective measures were

studied to give the NRC or other future analysts an idea of the relative

in^ortance of different corrective actions. The overall effects of PTS

corrective measures on plant safety and their cost effectiveness have not

been examined.

An analysis of the uncertainties performed by SAI and ORNL is described in

Chapter 7, in which the major contributors to the uncertainty in overall

PTS risks are identified.

Conclusions of the study and recommendations are given in Chapter 8. It

should be noted that Appendix G is not referred to in the text but

represents a series of utility comments and the authors' responses to those

comments.

REFERENCES

1. D. L. Selby, fit al., Pressurized Thermal Shock Evaulation of Calvert

Cliffs Unit 1 Nuclear Power Plant. NUREG/CR-4022 (ORNL/TM-9408), Sep­

tember 1985.

2. D. L. Selby, fii j^l.. Pressurized Thermal Shock Evaulation of H. B.

Robinson Unit 2 Nuclear Power Plant. NUREG/CR-4183 (ORNL/TM-9567),

September 1985.

1.8

2.0 PLANT DESIGNS AND OPEBATIONS PERTINENT TO PRESSURIZED THERMAL SHOCK

L. B. LaMonica, Science Applications. Incorporated

2.1 Introduction

The elenents working together in PTS situations include the physical design

of plant systems, actions of automatic controls, and operator interwention.

These elements influence both thermal-hydraulic and probabilistic analyses

of overcooling events. This section describes only the hardware systems,

controls, and operations pertinent to PIS risk evaluation. A complete

description of the Oconee-1 plant is beyond the scope of this document.

This section includes summary descriptions of the reactor cooling system

(RCS) primary and the feedwater, steam generator, and steam distribution

(secondary) systems. The physical relationships of these systems as they

bear on PTS is addressed. More general discussions of Oconee-1 systems2 1 2 2 2 3may be obtained from the Oconee FSAR ' and other sources. * ' * The

instrumentation and controls influencing the response of the primary and

secondary loops and the plant auxiliaries are discussed in Section 2.2.

Section 2.3 addresses the intended operation of hardware and controls in

conjunction with operator actions as defined by plant procedures.

2.2 Svstems

2.2.1 Reactor Cooling Systems (RCS)

The Oconee-1 Nuclear Power Station employs a Babcock Si Wilcox (BSiW) designed

177 fuel assembly pressurized water reactor (PWR) rated at 2568 MWt. The

two cooling loops, A and B, consist of a hot leg, a once-through steam

2.1

generator (OTSG), two reactor coolant pnaps (RCP) per loop, and two cold

legs per loop. The unit is of lonered loop design, meaning the bases of

the steam generators lie below the horizontal plane through the top of the

reactor core. This arrangement is illustrated in Figure 2.1. The cold

legs discharge coolant into an annular downcomer between the vessel wall

and the thermal shield (Figure 2.2). The coolant flows down to the lower

plenum and then up through the core region to the upper plenum and into the

hot legs. The pressures, temperatures, and mass flows for this system at

hot standby and full power conditions are summarized in Table 2.1.

A pressurizer vessel connected to loop A provides pressure control for the

primary coolant system. The coolant inventory control system augments the

pressure control function by adding or withdrawing coolant based on indi­

cated inventory.

The emergency core cooling systems (ECCS) include high-pressure injection

(HPI), core flood tanks (CFT), and low-pressure injection systems (LPI).

These safety grade systems inject cool water into the primary to prevent

fuel overheating under accident conditions. The HPI system can also

repressurize the RCS for certain small-break loss-of-coolant accident

(LOCA) and overcooling events and so is an important factor in PTS evalua­

tion.

The features of the different reactor cooling system components are

described below.

2.2

COAfi P lO O O rANK 8

R 6 U E F V A L V e N O ZZ L E SC O flE ^L O O O

tA M K AV ENT LIN E

SP ttA V LINE

PR E SSU R E T A PPAESSUniZEK

PU M P A U X IL IA R Yp e e o w a t e r

IN L E TFLOWTA P

PR E SS U R E TAP

^M0T"T0

IN JEC T IO Nn o z z l e

SU R G E LIN E

FLOW T A PPU M P A l

A U X IL IA R Y

FEED W ATERinlet

‘COLO"^®EAM

G E N E R A T O RIN JE C T IO N

R E A C T O R V ESSEL \ STEA Mp v G E N E R A T O R

LP IN JEC T IO N N O ZZ L E

MAIN FE E D W A T E R H E A D E R

D ECA Y h e a t n o z z l e

.L P IN JE C T IO N

y N O ZZ L E

M AIN FE E D W A T E R H E A D E R

COLO ''’0H P IN JE C T IO N N O ZZ L E

Figure 2.1 Oconee—1 PWR coolant system.

2.3

Control Rod Drive

Closure Head

Control Rod Assembly ' ' Studs

Internals Vent Valve

PlenumAssembly Control Rod

Guide Tube

Core Support Shield

Inlet Nozzle (one of 4)

Outlet Nozzle ^ (one of 2 —rotated for illustration)

Fuel Assembly

Core Barrel

Reactor Vessel

Surveillance Specimen — Holder Tube

\ Core Thermal Shield

Guide LugsLower Grid rnrt?h h )Flow Distributor In-Core Instrument

Guide Tube

Figure 2.2 Detail of Oconee-1 PWR vessel.

2.4

Table 2,1 Oconee-I PWR steady state conditions2 .4 .2.5

Parameter Full Power Hot Zero Power

RCS Primarv

Power (MW) 2568.0 9.0Coolant flow rate, total (Eg/s) 17640.0Hot leg temperature (K) 589.3Cold leg temperature (E) 563.5 551.0Primary pressure (MPa) 14.96 14.8Core pressure drop (MPa) 0.11Vessel pressure drop (MPa) 0.41Pressurizer water level (m) 5.6HPI/LfI coolant temperature (E) 305.4 305.4Accumulator coolant temperature 305.4 305.4

Feedwater flow per loop (Eg/sec) 680.4Feedwater temperature (E) 511.0 305.4Steam generator outlet pressure (Mpa) 6.38 6.21Steam outlet superbeat (E) 33.3 0.0Steam generator secondary inventory (Eg) <1.77E4 <2.64E4Steam generator nominal level (m) 6.1 (operating) 9.1 (staiMFW pump inlet pressure (MPa) 2.77MFW pump inlet temperature (E) 461.0 305.4C.B. pump inlet pressure (MPa) 0.8C.B. pump inlet temperature (E) 308.3 305.4Hotwell pressure (MPa) 0.01 0.01Hotwell temperature (E) 305.4 305.4Hotwell inventory (Eg) 5.31E5 5.31E5Upper surge tank inventory (Eg) 2.69E5 2.69E5

2.5

2.2.1.1 Reactor Vessel

The reactor pressure vessel is illustrated in Figure 2.2. The core barrel

divides the voluae of the vessel into a core region and an annular region

called the downcomer. The core barrel provides structural support for

the core and defines the coolant flow path. Coolant enters the downcomer

annulus through the four cold leg nozzles located on an elevation above

the top of the core. The two hot leg nozzles pass through the downcomer

region and the core barrel and have the same center-line elevation as the

cold leg nozzles.

There are eight vent valves in the core barrel above the hot and cold

leg nozzles. The primary purpose of the vent valves is to facilitate

core reflooding following a postulated large-break LOCA in the reactor

cold leg piping by allowing flow of steam from the upper plenum to the

break. The vent valves also allow flow of hot water into the downcomer

region during PTS transients when natural circulation flow is restricted

or lost. The hot vent valve flow mixes with the HPI flow to moderate

downcomer temperatures.

Each vent valve consists of a hinged disc and valve body situated to remain

closed under normal operating conditions (i.e., with RCP running). When

natural circulation and/or flow stagnation is experienced, the differential

pressure drop between the downcomer and upper plenum reverses, causing the

valves to open. The valves begin to open on a differential pressure of

0.85 EPa (0.125 paid) and are fully open at 1.79 KPa (0.26 paid).

2.6

Besides these hydraulic characteristics, the vessel eabodies metallurgical

and neutron fluence factors important to PTS. These are discussed in

Chapter 5.

2.2.1.2 Steam Generators and Primary Piping

The configuration of the once-through steam generators is depicted in

Figure 2.3. In this configuration the primary coolant makes a single

pass from top to bottom through straight tubes. Steam generated outside

the tubes flows up the shell side of the steam generator, countercurrent

to primary coolant downward flow. This arrangement promotes superheating

of steam during normal operations. During transient operation, primary

reheating (reverse heat transfer) by steam condensation on the tubes may

contribute to loop flow stagnation. The secondary side of the steam

generators is discussed in Section 2.2.2.

The hot leg pipes connecting the vessel outlet to the upper plenum of each

steam generator are referred to as "candy canes" due to their appearance

(see Figure 2.1). Under natural circulation conditions, steam voids may

collect at the top of these pipes and block natural circulation flow in

the loop.

Coolant exits the tubes at the lower plenum of the steam generator. The

loop flow is split between the two cold legs at the lower plenum of the

steam generator (Figures 2.1 and 2.3). The piping forms a trap or loop

seal at its lowest point and then runs upward to the reactor coolant pumps

at the same level as the vessel inlet-outlet nozzles.

2.7

R eactor Coolant Inlet

M anw ayInspection P o rt

8 in. minT u b e sh e e t

Vent & Level S ensing

M anway

6 .6 2 5 in. min

Auxiliary Feedw ater Inlet

■Tube S u p p o rt P la te s

U pper Baffle H andhole

6 .6 2 5 in. minDrain

Steam O utlet

F eed w ater InletLevel Sensing

Level S ensingTtierm owell

4 .1 8 7 in. min 1 3 8 in. ID,=11Lower Baffle

Level S ensing

6 .6 2 5 in. min

M anwayDrain & S am ple

H andholeTherm ow ell

Level S ensing

T u b esh ee tDrain

R eactor C oolant O utlet

M anway

Inspection P o rtDrain

Figure 2.3 Detail of once through steam generator.

2 . 8

2.2.1.3 Reactor Coolant Pumps

Forced circulation is maintained by four reactor coolant pumps (RCP), tvo

on each loop. Each pnmp has a rated flow of 5.56 m /s (88,000 gpm) with

a developed head of 0.78 HPa (113 psid) . The rated maximum pump power

is 6.7 MV (9000 hp) per pump. The pnmp flywheel inertia is sufficient

to prolong pump spindown for about 100 s after trip, maintaining forced

circulation for the same period.

2.2.1.4 Pressurizer and Pressure Control

The pressurizer, depicted in Figure 2.4, serves as an expansion or surge

tank for controlling system pressure. A 0.254m (10-in.) i.d. pipe

connects the pressurizer to the loop A hot leg. During normal operation3 3 3 3the pressurizer contains 19.8m (700 ft ) of steam and 22.7m (800 ft ) of

water at saturation conditions. The pressurizer heater has a maximum input

capacity of 1.638 MW. Rapid overcooling incidents usually lower the water

level below the heater trip level, removing the heater from operation.

Unless it is manually reset, the heater has little influence on pressure

recovery for overcooling events.

The pressurizer is also equipped with one power-operated relief valve

(PORV) and two code safety relief valves. A motor-operated block valve can

be used to isolate the PORV. The PORV has an effective inside diameter of

2.77 cm (1.09 in.) and a design steam flow capacity of 13.51 kg/s (107,000

Ib/h) . The PORV is programmed to open at 16.9 MPa (2450 psig) and close

at 16.6 MPa (2400 psig). The two code safety relief valves each have an

effective inside diameter of 4.57 cm (1.8 in.) and together have a design

2.9

Vent Nozzle Relief Valve Nozzle (typical of 3)

Water Spray Nozzle

Vessel Supports

Rotated for Illustration

Water Spray CJonnection from Reactor Coolant

Inlet Line

Level Sensing Nozzle (typical of 3)

Steam Space

Normal Water Level

Thermowell (Sample Nozzle behind)

Electric Heater Bundle

Level Sensing Nozzle (typical of 3)

Surge Diffuser

Surge Line Nozzle from Reactor Coolant

Outlet Line

Figure 2.4 Detail of pressurizer. 2.10

steam flow capacity of 84.2 kg/s (667,000 Ib/h) . The code safety relief

valves begin opening at a system pressure of 17.2 MPa (2,500 psig).

2.2.1.5 Emergency Core Cooling Systems

High-Pressure Injection System

The high-pressure injection (HPI) system consists of three motor-driven

centrifugal pumps and a header system that can deliver flow to each of

the cold legs downstream of the respective reactor coolant pumps. During

normal operation, one pump in the HPI system runs continuously as part of

the inventory control system, injecting makeup water into the loop A cold

legs to counter the letdown flow.

When transient events cause depressurization of the primary system to

below 10.34 MPa (1500 psig), the safety injection actuation signal starts

the two remaining pumps and aligns valves to provide a path for pumping

borated water from the borated water storage tank into all four cold legs.

Approximately two-thirds of the total flow enters loop A and the remainder

enters loop B. Since the HPI system uses centrifugal pumps, the total

flow rate is a function of cooling system pressure. This relationship is

presented in Figure 2.5. The HPI system can repressurize an intact primary

coolant system up to the safety relief valve set point (2500 psig) and can

partially repressurize the system during certain small-break LOCA events.

After actuation by the safety injection signal, the HPI system remains in

operation until it is manually shut off.

2.11

PSIA

N5I—*ro

2800

2500

2100

1800

1500

T OTAL FLOW1200

A LOOP

8 LOOP900

600

3 00

100

200 4 0 0 500 60 00 100 3 00 7 00 8 0 0 9 0 0 1100 12001000

Figure 2.5 High pressure injection system flow capacity.

Core Flood Tanks

3The two core flood tanks (CFT) store a total of 59 m (15,560 gal) of

borated water under a nitrogen gas blanket at 4.14 MPa (600 psig). If

a LOCA or a severe overcooling incident reduces the RCS pressure below

the pressure in the core flood tanks, check valves in the 0.356n>- (14-in.)

i.d. CFT discharge lines will open and the cool, borated water will begin

flowing into the reactor vessel downcomer at the two core flood nozzles

located 2 ft above the plane of the reactor inlet-outlet nozzles and

diametrically opposed to each other (see Figure 2.1). Continued decreases

in RCS pressure are necessary to sustain flow from the CFTs into the

vessel.

Low-Pressure Injection

When the RCS pressure drops below 3.45 MPa (500 psig), the low-pressure

injection (LPI) pumps start and the pump suction and discharge valves are

realigned for injection of water from the borated water storage tank into

the reactor vessel downcomer at the core flood nozzles. There is no LPI

flow until the RCS pressure drops to 1.38 MPa (200 psig), the LPI pump3

shutoff pressure. At 0.69 MPa (100 psig), a total of 0.379 m /s (6,000

gpm) is delivered by LPI. By further realignment of pump suction and

discharge valves, the LPI system may also function in the residual heat

removal system and other functions not related to PTS. Due to the low

primary pressures present when the LPI system is operating, this system

will not make any significant contribution to PTS risk.

2.13

2.2.2 Feedwater and Steam Systems

The steam generators and their associated feedwater system and pressure

control systems play a pivotal role in PTS sequences. The steam generators

provide cooling to the reactor coolant system during both normal operations

and overcooling events. The performance of the various feedwater and steam

system components influences the rate of cooldown during an accident. The

feedwater and steam systems form a closed loop as illustrated in Figure

2.6. The portions of the loop most significant to PTS events are indicated

by bold flow lines. The main feedwater (HFW) train runs from the condenser

hotwell to the steam generators and supplies a regulated flow of preheated

water. The emergency feedwater (EFW) train (not depicted on Figure 2.6)

pumps cool water from the condenser hotwell and/or the upper (condensate)

surge tank directly to the steam generators without any preheating.

The two once-through steam generators are capable of generating 2.45 x 10^

kg/h (5.39 X 10^ Ib/h) of steam at 6.27 MPa (910 psia) and 572 K (570°F).

The once-through steam generator design yields steam superheats of 33.3

(60^F) to improve power cycle efficiency. Achievement of these steam

conditions requires precise control of feedwater flows via the integrated

control system (ICS).

The main steam lines connect the steam generators to the high-pressure

turbine header at the turbine stop valves. A scoping study of the steam2 6and power conversion systems * suggests that the turbine stop valves serve

as the boundary point for PTS modeling of the Oconee-1 plant. Failure of

a stop valve will yield no impact if the turbine control valves operate

properly or will yield conditions similar to a small or large steam

2.14

N3h-*Ui

C\ A

26 24 25l l23

Sica* Gcncr stor k $t«a« Gcnarator 0Hafn Steaalin* Saf«ty/fi«l(«f Valvct Main Sltanlinc Turbfr.i 9yp>«ss Va)v«s To Cona«ns«'STo Main Fc<!Owat«r Pump T'jrbfraiTo Concanscr Slaai Air ijactortTo Cm«rgcncy FccCwatar P*.»p TurbineHlg.b-prenurt Torplre SlcpHigb*pr«j»ure TorolnaR«h«atar/Moisturc Stparaicr Assemolltileheatcr Crain PumpMoisture Separator Drain PumpsLow-pressure TurbinesCondensersHotwc11sUpper Surge TanksKotwe11 PumpsPo I i sher/DemInera}TierCondensate CoolersGeneral Water CoolersHydrogen CoolersCondenser Steas Air EjectorsFrom Main SteamllnesSteam Seal CondensersFrom Turbine Steam SealsTo Condensate Storage TanksCondensate Booster Pumoslow-pressure F Condensate Heaterslow-pressure E Condensate HeatersLow-pressure E Condensate Heater Drain Pumpslow-pressu e 9 Condensate HeatersLow-pressure D Condensate Heater flash TanksLow-pressure D Condensate Heater Drain PumpsLow-pressure C Condensate HeatersLow-pressure C Ccnoensate Heater Flasn TanksLow-pressure C Conoensate Heater Drain CoolerfMain feedwater PlumpsMain Feedwater Pump TurbinesHigh-pressure 9 Fceowater HeaterfHigh-pressure A Feedwater HeatersMain Control Valves

Figure 2.6 Oconee-1 main feedwater, steam, and power systems.

line break if the turbine control valves fail. The operation of the

turbines, being dovnstreaai from the stop valves, bears no direct ia^act

on PIS. Feedvater heating steam from the nnmerons extraction lines is

lost immediately after tnrbine trip and does not require extensive modeling

other than to determine the temperature decay for the MFW flow. The

pertinent characteristics of the main feedwater, emergency feedwater, steam

generator, and main steam line systems are discussed in detail below.

2.2.2.1 Main Feedwater Train

The main feedwater train (MFW) or main condensate/feedwater train is

schematically illustrated in Figure 2.6. The prime function of the

main condensate/feedwater train is to transport subcooled water from the

hotwell outlets to the steam generator main feedwater inlets while both

pressurizing and heating it. A second obvious function of this train is to

control the quantity of feedwater reaching the secondary side of each steam

generator. The control function is implemented by the integrated control

system (ICS), which is described in Section 2.2.3.

The main condensate/feedwater train begins with low-pressure, low-

temperature subcooled condensate exiting the hotwells. The condensate

is immediately pressurized by three parallel motor-driven hotwell pumps.

These pumps together have a rated flow of 0.8 m /s (12,678 gpm) at a

differential pressure of 1.152 MPa (167 psi). The pressure rise across

the pumps at zero flow would be 1.42 MPa (206 psi). The hotwell pumps

will trip on low level in the hotwell and on loss of condenser vacuum.

2.16

The condensate then flovs through the polisher/demineralizers, resin trap,

and the tube sides of the condensate coolers, hydrogen coolers, general

water coolers (these coolers are known collectively as the plant heat dump),

condensate steam air ejector, and steam seal condensers. The slightly

warmer, low-pressure subcooled condensate leaving the steam seal condensers

is then pressurized by three parallel motor-driven condensate booster pumps

whose function is to provide adequate suction pressure to the main feedwater

pumps after the frictional losses of the low-pressure condensate heaters.

The differential pressure rise generated by the condensate booster pumps

is 2.94 MPa (426 psi) at rated flow. At zero flow the pressure rise across

these pumps would be 3.14 MPa (455 psi). The condensate booster pumps will

trip on sustained low suction pressure of 0.21 MPa (30.7 psi).

Departing from the condensate booster pumps, the condensate is heated

significantly by passage through the tube side of four stages of low-

pressure condensate heaters. The first stage consists of three parallel

low-pressure condensate heaters (F heaters): the second stage consists of

two parallel low-pressure condensate heaters (E heaters): the third stage

consists of two parallel low-pressure condensate heaters (D heaters) in

series with two parallel low-pressure condensate heaters (C heaters). The

condensate next travels to the two parallel turbine-driven main feedwater

pumps that provide final pressurization of the feedwater. Frictional los­

ses in the high-pressure A and B feedwater heaters and main control valves

reduce the feedwater pressure to the desired delivery pressure at the steam

generator main feedwater inlets. The integrated control system (ICS)

varies both the main feedwater pump speed and feedwater control valve posi­

tion to maintain optimum control of flow rate and pressure drop. The ICS

2.17

is discussed in Section 2.2.3. The main feedwater pumps will trip on high

discharge pressure of 8.89 MPa (1289.7 psi)» low suction pressure of 1.72

MPa (249.7 psia), and high steam generator level. Should the MFW pumps

trip, the hotwell and condensate booster pnmps would be capable of deliver­

ing flow to the steam generators at pressures up to about 3.80 MPa (550

psig). At higher pressures no flow would be delivered.

Upon exiting the common main feedwater pnmp discharge header, the subcooled

feedwater is further heated to the desired delivery temperature, 511 K

(460**F) by two banks of high-pressure feedwater heaters in series (B

heaters and A heaters). The feedwater recombines in the high-pressure A

feedwater heater outlet header before dividing into two lines containing

the main control valves and arriving at the steam generator main feedwater

headers. Each main control valve has a startup control valve in parallel

(Figure 2.7). The startup control valve is used for low-power conditions

until feedwater control can be accomplished with the main control valve.

At Oconee, there is no automatic feedwater isolation function separate from

the main and startup flow control valves. However, the operator can iso­

late feedwater using available block valves.

There is a cross-connect from the main feedwater train to the emergency

feedwater train. This cross-connect is activated by the feedwater

realignment trip which follows RCP trip and resetting of the steam generator

level controls. The feedwater realignment valves redirect the startup

control valve flow away from the main feedwater header to the emergency

feedwater header. Therefore, heated water is made available for filling

2.18

E ME RG E NC YF EE DWA T ER - [ X 3 ------- NORMALLY O P E N

E ME R GE N CYF EE DW A T E R

HE ADER

STEAMG E NE R A T O R

K) (— *

MAINF EE DW A T E R

H EADER

NORMALLY C L O SE DEFWV

X

S UF CV

i X }

MFCV

{XI—[X}6

F EE DW A T E RTRAIN

3

123

4.56

EFWVSUFCV

MFCV

EM E R GE N CY F E E D W A T E R C H E C K VALVE R E ALIGNMENT C H E C K VALVE MAIN F E E D W A T E R C H E C K VALVE F EE DW A T E R R E AL IGNMENT VALVES MAIN F E E D WA T ER BLOCK VALVES E M E R GE N CY F E E D WA T ER VALVE STAR TUP F L O W C O N T R O L VALVE MAIN F L O W CO N T R O L VALVE

Figure 2.7 Oconee-1 feedwater valve schematic.

tlie steam generator to the natural circulation set point level, or 60%

of the indicated range, thus enhancing natural circulation with less

overcooling of the primary.

2.2.2.2 Emergency Feedwater Train

The emergency feedwater (EFW) train consists of two motor-driven pumps

(one to each steam generator) and one turbine-driven pump whose discharge

is cross-connected to the discharges of both motor-driven pumps. The

motor-driven pumps draw low-pressure, low-temperature subcooled condensate

from the upper surge tanks and/or the hotwells. High-pressure subcooled

feedwater from the combined emergency turbine- and motor-driven pumps

continues to the secondary-side emergency feedwater inlet of each steam

generator through independent lines containing a steam generator level

control valve. The level control function is independent of the ICS. A

one-way cross-connect exists for each steam generator downstream of the

level control valve to allow main feedwater to enter the emergency feedwater

lines (Figure 2.7). Insignificant heating of the feedwater occurs in the

emergency feedwater train. Check valves throughout the emergency feedwater

train prevent improper reverse flows throughout the train.

The emergency feedwater pumps are activated when the main feedwater pumps

trip off or if MFW pressure drops below 750 psig. The emergency feedwater

pumps continue running until shut off manually or tripped because of

mechanical failure.

2.20

2.2.2.3 Steam Generators

The configuration of the once-through steam generators is depicted in

Figure 2.3. Subcooled main feedwater enters (vertically downward) the

secondary side of each once-through steam generator (labeled A and B)

through a spray header system, which is located approximately at the

midsection of the steam generator. Steam aspirated from the steam generator

shell region mixes with the feedwater as it travels through the steam

generator downcomer. The feedwater is close to saturation temperature as

it leaves the steam generator downcomer. Leaving the downcomer, the fluid

turns vertically upward in the secondary-side (shell) region of the tube

bundle where it is converted to saturated steam before reaching the level

of the aspirators (slightly below the level of the main feedwater spray

header) . It is superheated during the rest of its passage up the shell

side of the steam generator. Steam exits the steam generator by turning

downward into an annulus that leads to the main steam outlets (located

slightly above the main feedwater spray header). Emergency feedwater is

injected radially through a spray header directly into the secondary side

of the tube bundle at a level near the top of the tube bundle. The

emergency feedwater spray header is intended to provide adequate cooling

to assure natural circulation until the steam generator level reaches 50

% of the indicator range, corresponding to 6.1 m (20 ft) of water, at which

level natural circulation will continue.

Level in the steam generator is determined from differential pressure

measurements taken from taps, as indicated in Figure 2.3. The Oconee-1

plant is equipped with a main feedwater overfill protection feature. The

2.21

protection system monitors the steam generator differential taps and trips

the main feedwater pomps when either steam generator exceeds 90% of indica­

tor range.

2.2.2.4 Main Steam Lines

The main steam lines run from the steam generators to the main steam

line penetrations of the containment and into the tnrbine bnilding. Eight

safety/relief valves located on each main steam line limit steam line

pressure by venting to the atmosphere excess main steam line mass flow that

cannot be accommodated by the tnrbine bypass steam lines. The relief valve

set points range from 7.24 MPa (1050 psig) to 7.61 MPa (1104 psig). With

all 16 valves open, 114% of the design steam flow may be vented to the

atmosphere.

Unlike many other plants, Oconee-1 has no main steam isolation valves.

Down-stream from the safety valve taps, there are branches to several

possible destinations; the condenser via the tnrbine bypass steam lines, the

steam turbines that drive both main feedwater pnmps and the tnrbine-driven

emergency feedwater pnmp, the reheater/moistnre separator assemblies, the

condenser air ejector assembly, and the tnrbine stop valves. The tnrbine

governor valves and the high-pressure tnrbine are downstream of the tnrbine

stop valves.

A manually actuated atmospheric dump valve is provided on each main steam

line. Because of the large time lag expected for manual operation of

these valves, it is unlikely that they could contribute significantly to

the progress or control of an overcooling event.

2.22

The turbine bypass valves are used to control steam system and RCS

temperature during lov-pover and transient conditions. There are two of

these valves on each steam line, making a total of four valves. The

turbine bypass valve system can vent 25% of full-power steam flow to the

condensers. The control of these valves is discussed in Section 2.2.3.

2,2.3 Control Systems

The integrated control system (ICS) is a comprehensive system that

controls all power generation operations of the plant. Separate safety

instrumentation and controls are provided for mitigation of and recovery

from transient conditions. Nevertheless, the scope of the ICS is such that

it can significantly influence the course of an overcooling event. Figure

2.8 diagrams the Oconee-1 control system hierarchy. The higher-order

segments such as the auto dispatch system and unit load demand generate

a power demand signal that serves as a set point for the lower control

systems. The integrated master system coordinates the activities of the

reactor control, feedwater control, and (secondary steam) pressure control

systems to compensate for upsets in any of the lower-order systems and to

satisfy the demands of the higher-level systems.

The contributions of the ICS to PTS risk are twofold. First, failures

in the ICS can initiate reactor trip and such overcooling events as steam

generator overfeed and turbine bypass valve control failure. Therefore,

the ICS can influence the frequency and, to an extent, the type of event

initiators. Second, after the initiation of an overcooling event, portions

of the ICS (namely, feedwater control and pressure control) can influence

the response of the plant to the initiator. The structure of the ICS

2.23

F E E D WA T ERC O N T R O L

P R E S S U R EC O N T R O L

T URBI NEB YP AS SVALVES

S T G E N B VALVES

MF WP U M P S

S T G E N A VALVES

TURBI NEVALVES

C O N T R O LROD

DRIVES

R E AC T ORC O N T R O L

I NTEGRATED MA ST ER

UNIT LOAD DEMAND

AUTO D I SPA TC H SYS TE M

Figure 2.8 Oconee-1 control systems hierarchy.

2.24

pertaining to feedwater control and pressure control is important to the2 7thermal-hydraulic analysis of the plant. * These systems are described in

the following sections.

2.2.3.1 ICS Feedwater Control Logic

This section briefly summarizes the control algorithm implemented in the

ICS for feedwater control. The discussion includes the necessary signals

from the unit load demand and reactor control systems and describes the

feedwater control logic concisely without detailing other ICS functions

not directly related to PTS. The different elements of the ICS feedwater

control system are diagrammed in Figure 2.9.

Unit Load/Reactor/Feedwater Demand Characterization

The unit load demand subsystem (ULD) establishes the demand for megawatt

generation of the unit. Many conditions within the unit can result in

preventing the unit from generating the requested megawatts. In this

case, the unit must follow the limiting variable in order to maintain

coordination of all the control variables. This mode of operation is

termed "traching," and the generated power signal is used as the indication

of the limited variable. Although several conditions cause a transfer

to the tracking mode, only reactor trip is pertinent in the transients

to be considered. Since a turbine trip also produces an anticipatory

reactor trip, this condition is included. On reactor trip, ULD tracks

generated megawatts at a maximum rate of 20% full power per minute (FP/min).

Since the generated megawatts will fall off much faster than 20% FP/min,

the ULD can be modeled effectively with a 20% FP/min ramp initiated at

2.25

N5K>

FeedwaterFlow

LevelLimiters

BTU Limiter

MFW Pump Speed Control

Feedwater Valves Control

Neutron Power Cross Limiter

MFCV Pressure Drop

Figure 2.9 ICS feedwater control scheme.

reactor trip. If one or more reactor coolant pumps or main feeduater pumps

are tripped before ULD runback is complete, then the runback rate becomes

50% FP/min instead of 20% FP/min. Since the primary runback signal to

feedwater control is the neutron cross-limit and the Btu limit, this is not

considered significant. If operational transients were to be considered,

the additional detail would be required.

Reactor demand is scaled from ULD to provide the required reactor power at

steady state. This scaling is necessary since full-scale ranges of reactor

power, feedwater flow, and generated megawatts are somewhat different. The

reactor demand signal is then limited between 10% and 103%. The neutron

power signal is compared with the reactor demand signal to develop the

neutron power error. The resultant signal is sent to the feedwater control

subsystem for cross-limiting feedwater demand.

Feedwater demand is characterized from the ULD to provide the required

steam flow for a given power level at steady state. This characterization

is such that the nominal feedwater flow rate is requested at full-power

conditions.

Compensated Feedwater Demand

The steam generator demand is characterized to represent the expected

feedwater temperature. This signal is compared to the actual feedwater

temperature to produce a feedwater temperature error signal that compensates

the feedwater demand.

The neutron error signal from the reactor control subsystem can also modify

the total feedwater demand. If the neutron error becomes greater than

2.27

± 5%, the total feedwater demand will be modified to maintain the proper

ratio between feedwater flow and reactor power. If this signal is greater

than + 5%, the nnit is said to be operating under "cross limits." Note that

after a reactor trip, it is the cross-limit signal that initiates rapid

runback of feedwater flow since the ULD ramp rate is merely 20% FP/min.

Feedwater Loop A and B Demand

Separate feedwater flow demands are developed for loop A and B. In the ICS,

these demands are characterized to meet the requirements of total feedwater

demand and to maintain a set point temperature differential (normally zero)

between the two reactor cold legs. Since this ratio controller output

is blocked when either steam generator is on a level limit or during a

transient, it is not important. Consequently, the total feedwater demand

signal can be sent unmodified to each loop in the model used for FTS

studies.

BTU Limited Feedwater (FW) Demand

The outlet steam pressure of each steam generator is characterized to

produce a signal equivalent to the FW flow limit for that pressure.

Likewise, the FW temperature, the selected reactor outlet temperature, and

primary loop flow are conditioned to produce equivalent FW flow limit

signals. These signals are then used to develop a Btu availability

limit signal, which limits the feedwater demand for the steam generator

to prevent a reduction in steam temperature. The Btu signal is then

auctioneered against the loop demand signal. The limiting signal (lower

2.28

FW demand) is used to develop the loop demand for MFW pnmp control and

in the development of the FW flov error signal.

Feedwater Flow Error

The loop FW flow signal is compared with the FW flow demand to produce

the loop FW flow error. The total FW flow in the loop is obtained from

the sum of the startup and main feedwater flows. The measured flow is

fed through a lag unit to produce a more stable control signal.

High and Low Steam Generator Downcomer Level Limits

The FW flow error signal is compared with high- and low-level error

signals. Thus, if the FW flow error demands an increase in FW flow and

the downcomer level is at the maximum allowable, the level error signal

will assume control to prevent flooding of the aspirating steam ports.

Similarly, if the FW flow error tries to reduce the FW flow to a point

where the downcomer level drops below the minimum allowable value, the low-

level error signal will take control.

Feedwater Valve Control

The level-limited FW demand error is used for control of the main and

startup FW valves. Proportional plus integral (P + I) action is applied

to the error signal from two different controllers. During level control

at the low-level limit, one of the controllers is used while the output

of the other controller is blocked. When not on low-level control, the

level controller is blocked and the other controller provides the control

2.29

signal to the valves. Smooth transfer is provided when snitching from one

control signal to the other.

Feedwater Pnmp Control

Loop A and B FW valve differential pressure signals are auctioneered to

select the signal representing the smaller differential pressure. The

selected signal is then compared with the minimum differential pressure set

point to produce an error signal. This error signal is modified with a

gaining factor, which increases as the error increases. Proportional and

integral action is applied to this error signal. The resultant signal is

used to modify the total pump demand signal.

The modified FW demand signals from loop A and loop B are summed to produce

a total FW demand signal used as the demand signal for the FW pumps. On a

load change, this signal will anticipate a change in differential pressure

and cause the pump speed to change, thus minimizing the error.

Feedwater Control System Set Points

The set points used in modeling the Oconee feedwater control system are

given below.

2.30

Limit or Set Points

Expected FW temperature

Btu limits

High level limit

Low level limit

Low level limit

FW valve AP

Value

Function developed by ICS

Function developed by ICS

8.14 m (344 in.) H^O

0.64 m (25 in.) H^o

6.1 m (240 in.) H^O

0.24 MPa (35 PSID)

Remarks

RC pump(s) operating

RC pump(s) tripped

2.2 .3.2 Description of Turbine Bypass Valve Control

Turbine control is a portion of the integrated master subsystem of the

ICS. Since the simulation models do not include the turbine, modeling the

turbine control valve is not necessary. Thus, the turbine header pressure

is a boundary condition for the ICS model.

Turbine bypass control provides high-pressure relief if the turbine header

pressure exceeds its set point by 0.34 MPa (50 psi) under noirmal conditions

or by 0.86 MPa (125 psi) if the reactor is tripped. The turbine header

pressure error is applied through proportional plus integral control.

Independent pressure relief is provided if the outlet pressure of either

steam generator exceeds its set point. This relief is direct, proportional

control action. The turbine bypass control system selects whichever

control signal requires more bypass steam flow around the turbine.

On loss of condenser vacuum, the turbine bypass valves are shut to avoid

sending further steam to the condenser.

2.31

2.2.3.3 Description of Emergency Feednater Valve Control Logic

Emergency feedwater control systems manipnlate a control valve to maintain

level in the steam generator. The startup level is maintained if the

reactor coolant pnmps are operating, and a 6.1-m (20-ft) level is maintained

if they are tripped. This is to encourage natural circulation during

conditions when the reactor coolant pumps are tripped. The actual steam

generator level (as determined for MFW control) is compared with the level

set point, and EFW flow to the steam generator is adjusted accordingly.

There is no automatic isolation of feedwater to a steam generator with a

steam line break or similar depressurization event.

2.2.4 Support Systems

Support systems supply power or cooling to many of the major systems and

components described in Sections 2.2.1 to 2.2.3. These support systems

were considered because of the potential of single failures of support sys­

tems to lead to overcooling transients in nuclear power plants. The prin­

cipal support systems in the Oconee—1 plant are

Cooling water systems (CWS),

Instrument air systems (IAS), and

Electrical and instrumentation power systems (EPS).

Each of these systems has redundant busses or trains or alternate backup

systems. The detailed description of these systems is beyond the scope

of this section. An interaction evaluation of the support systems was

2.32

performed to determine which failures would initiate or influence FTS2 8sequences. Six "systems" were identified as main candidates, namely:

(1) PORV

(2) HPI/reactor coolant makeup and purification (MD&P)

(3) Turbine bypass valves (TBV)

(4) Turbine trip

(5) Main feedwater

(6) Emergency feedwater

The PORV (and its controls) was selected since its failure in the open

position is a small LOCA, one of the PTS initiating transients of concern.

The HPI/NU&P system is required to operate to repressurize the RCS in

almost all PTS transients considered. In addition, the HPI/MD&P provides

RC pump seal injection, which is ia^ortant to the prevention of RC pump

seal failure. The turbine trip function and the IBV were selected since

untripped or open failures could result in steam generator depressurization

and RCS cooldown. The main or emergency feedwater systems' function

is required in all non-LOCA PTS transients to cause the RCS overcooling

condition.

The results of the interaction study are summarized in Table 2.2. The PORV

and its control circuitry do not depend on the the CWS directly or on the

IAS. The valve will be closed in the event of associated EPS failures.

The HPI/MU&P systems require cooling water, but a single failure is

overcome by manual changeover from low-pressure service water (LPSW) to

high-pressure service water (HPSW). Instrument air failures will cause the

2.33

Table 2.2 Failure nodes of systens in response to support*systens single failures

Systen CVS Failure IAS Failure EPS Failure

PORV Operable Operable •*ClosedHPI/MD P

o HPI Operable/off Operable Operable/offo Makeup control valve Operable Closed Manually/o RCP Seal Inj. control operable

valve Operable Open ThrottledTBV Operable/closed Closed Closed */

nanuallyoperable

Turbine trip Tripped Tripped TrippedMain feedwater Tripped As is ThrottledEnergency feedwater Operable/off Operable Operable

•Letter fron R.L. Gill, Jr. 19, 1982.

(Duke Power) to R.C. Kryter (ORNL), October

••Telecon with D.V. Henneke (Duke Power), Novenber 11, 1982. Source:Reference 2.8,

2.34

nakenp control valve to fail closed and the RCP seal injection valve to

fail open. EPS failure will, depending on which supply is lost, throttle

the valves and affect HPI motor control (i.e., start or stop motors already

running).

The turbine bypass valves will fail closed or be manually operable for any

single support system failure. Multiple failures causing erroneous signals

from the ICS may cause the valves to fail 50% open.

A disabling failure of any of these support systems will result in turbine

trip. Main feedwater will trip on loss of cooling to the feedwater pumps.

Loss of IAS will freeze the feedwater regulating valves in position. The

valves will throttle on EPS failure-related loss of control signal.

Because of backup electrical and air systems, the emergency feedwater

systems will initially function. Loss of backup pressurized-nitrogen

systems would cause the EFW control valves to fail open. Loss of cooling

could cause eventual failure or trip of the EFW pnmps.

2.3 Operations

The Oconee-1 plant systems and operating procedures are intended to provide

sufficient cooling to prevent core damage for sequences up to the design

basis accidents. Likewise, the design and operations also seek to limit RCS

cooldown rates to 55.56 K (100^F)/h, the design cooldown rate for reactor

vessel protection. RCS temperature and pressure response to overcooling

events are influenced by three main mechanisms:

(1) Automatic system responses.

2.35

(2) Operator intervention, and

(3) Passive features.

Antovatic responses include reactor and tnrbine trips, feedwater runback by

ICS, tnrbine bypass valve and PORV operation, HPI initiation, EFW initiation

and control, and other assorted autoaiatic trips. Operator interventions

include tripping and starting of reactor coolant puaps, throttling of HPI,

and manual control or isolation of selected systems. Such actions are

governed by written procedures. Passive features include the safety relief

valves for RCS and steam system pressure control, reactor vessel internal

vent valves, and design-related pheuimiena such as RCS natural circulation.

The normal interplay of these actors for overcooling sequences is discussed

below.

2.3.1 Reactor Trip

The normal reactor trip sequence represents the baseline against which

other more severe transients may be compared. Prior to the reactor trip,

the core power level is steady, the reactor coolant pumps are operating,

and the ICS is maintaining a constant steam flow corresponding to system

power output. The normal primary (RCS) flow paths are diagrammed in Figure

2.10. The initiating event is assumed to be external to the nuclear and

steam-generating systems. A turbine trip satisfies this assumption. The

turbine trip simultaneously triggers the reactor trip and begins closure of

the turbine stop valves in each main steam line. The ICS commences runback

of main feedwater by closing the main flow control valves (Figure 2.7),

throttling the startup flow control valves, and reducing main feedwater

pump speed. The ICS action is to track reactor power following the trip

2.36

H O T L E G P I P E

C O L D L E G P I P EP R E S S U R I Z E R

C O R ES U R G E L I N E

R E A C T O RV E S S E L

D O W N C O M E R

L H P I I N J E C T I O N N O Z Z L E

S T E A M G E N E R A T O R

Figure 2.10 RCS flow during normal operation.

2.37

and naintain atean generator water inventory without overfeeding the steaa

generators.

After the turbine stop valves close, the pressure in each steaa line

rises and the ICS opens the turbine bypass valves to relieve the pressure

and coaaence cooldown of the plant. Several of the steaa safety relief

valves aay also open aoaentarily after turbine stop valve closure. As

the RCS heat inventory and reactor power continue to decrease, the steaa

generation rate falls and the ICS sK>dulates the IBVs to aaintain constant

steaa generator pressure 6.97 MPa ClOlO psig) and. indirectly, constant

RCS teaperature. Therefore, the plant is brought to a steady condition

with the average RCS teaperature dropping to about 560 K (549^F) froa 577

K (579°F). Operator-ii^leaented cooldown procedures are then used to bring

the plant to shutdown condition.

The RCS also undergoes a pressure response related to its teaperature

response. Following reactor trip, heat transfer to the secondary side

causes reduction in coolant teaperature and specific voluae. Tliis coolant

shrinkage results in liquid flow out of the pressurizer. which in turn

leads to steaa expansion in the pressurizer doae and a drop in RCS

pressure. The pressurizer design voluae is saall relative to the rest of

the RCS so that coolant shrinkage froa aild transients can lead to loss of

pressurizer water level indication and tripping of the pressurizer heaters.

To aaintain pressurizer water level, the operator aay aanually start a

second HPI puap to coapleaent the noraal aakeup flow. (This operator

action was not aodeled in the transient analyses for this study.) The

aakeup flow stabilizes the RCS pressure and will cause repressurization

2.38

once the systea cooldown rate decreases. If the operator does not throttle

the HPI/makenp systea at soae lower pressnre, the RCS will reach the PORV

set point pressnre 16.9 MPa (2450 psig) where it will be regulated by the

action of the PORV. Written procedure specifies that the operator throttle

the aakeup systea on attainaent of 27.8 K (SO^F) subcooling in the RCS.

The flow regiae in the RCS is unaffected in this transient since the

reactor coolant puaps are not tripped.

2.3.2 LOCA Events

Loss-of-coolant accidents (LOCA) have the potential to generate stagnated

flow regiaes that can contribute to localized rapid cooldown of the reactor vessel. Depending on break size, the RCS aay reaain at high pressure

(saall breaks) or drop to low pressures (intermediate and large breaks).

The location of the break can also influence system flows and cooldown

rates. The general system responses to this type of event are described

below.

Prior to initiation of the break, the noraal circulation of the coolant is

as shown in Figure 2.10. After the break opens, the loss of coolant causes

a drop in pressure, which will cause reactor trip on P-T relationship or

low-pressure 12.41 MPa (1800 psig) and initiate HPI at 10.34 MPa (1500

psig). Operating procedures require the operator to trip all four reactor

coolant puaps following actuation of HPI. For very saall breaks, the HPI

system capacity is greater than the break flow, giving the operator control

over systea pressure and allowing orderly cooldown. For saall breaks

where the HPI capacity matches the break flow, the pressure will seek the

value dictated by the HPI pump head-capacity curves (Figure 2.5). Such

2.39

transients are characterized by a senisteady flov and pressure conditions

with teaiperature slowly declining as decay heat decreases. Beyond a

certain break size, the HPI cannot maintain pressure, so RCS pressure may

drop to 4.14 MPa (600 psig) where CFT flow begins or to 1.38 MPa (200 psig)

where LPI flow begins.

With the reactor coolant pumps tripped, continued heat transfer from the

primary to the secondary through the steam generators will induce coolant

density differences around the cooling loops and cause natural circulation

flow. This condition will continue until either steam voids collect in the

candy cane(s) interrupting flow or the RCS becomes cooler than the steam

generators, setting up opposing density gradients that result in a zero

net driving force for natural circulation flow. Despite the stagnation of

loop flows, the differences in downcomer and core region coolant density

are sufficient to yield circulation through the vent valves (see Figure 2.2

and Section 2.2.1). There is also a net flow towards the location of the

break. Figure 2.11 depicts the flow regime for a break at the top of the

pressurizer. The vent valves are designed to promote continued circulation

of coolant through the core region as well as provide warm water to mix

with HPI flows entering the downcomer region.

2.3.3 Secondary^Side Overcooling Events

Secondary^side overcooling events include steam line breaks and feedwater

overfeed events. Steam line breaks include stuck-open valves as well as

pipe breaks. The initial response of the RCS to a significant overfeed or

steam line break is similar to the response to a small-break LOCA; that is,

RCS pressure drops below the HPI initiation pressure and temperature

2.40

V A L V E

H O T L E G P I P

C O L O L E G P I P E

V E N T V A L V E

R E A C T O RV E S S E L

D O W N C O M E R

T O Q U E N C H T A N K

■ H P I I N J E C T I O N F R O M B W S T

S T E A MG E N E R A T O R

P R E S S U R I Z E R

S U R G E L I N E

Figure 2.11 RCS flows during SBLOCA at the top of the pressurizer.

2 . 4 1

declines rapidly. For this reason, the operator will handle the sequence

as a LOCA (i.e., trip the RCPs) until continued monitoring of the RCS and

steam generators allows elimination of LOCA concerns and confirmation of an

overfeed or steam line break.

Since the Oconee-1 plant is not equipped with main steam isolation valves

or main feedwater and EFW isolation systems and supporting logic systems,

feedwater isolation and TBV isolation, are accomplished by manual control.

The flow regime behavior is similar to that of the small-break LOCA

described above. The reactor coolant pumps, are tripped following actuation

of HPI. Natural circulation is initially established in both cooling loops.

This circulation will be for "symmetric" conditions such as overfeeds

to both steam generators or breaks affecting both steam lines. If only

one steam generator is subject to overcooling, natural circulation flows

will be nonsymmetric. The loop containing the intact steam generator may

stagnate if the RCS is cooled below the intact steam generator temperature,

causing cancelation of flow-driving potential for the loop. For severe

cooldown and primary depressurization events, voiding of the candy cane may

physically block flow of liquids. With the loss of loop flow, the vent

valves will allow continued core region to downcomer flow as in the LOCA

case, although flow rates will vary.

If the affected loop secondary dries out or is isolated, the system will

reheat until natural circulation is reestablished in the intact loop. The

intact loop then can be used for system heat removal during final shutdown.

2.42

REFERENCES

2.1. Duke Pover Company. "Oconee Nuclear Station Final Safety Analysis

Report," Chapters 4, 6, 7, 8, 9, 10.

2.2. Babcock & Wilcox. "Steam. Its Generation and Use." The

Babcock & Wilcox Company. New York. 1978. Chapters 21, 23. 35.

2.3. Duke Power Company. "Reactor Vessel Pressurized Thermal Shock

Evaluation." DPC-RS-1001. January 1982.

2.4. J. Ireland, et. al.. "TRAC Analyses of Severe Overcooling Transients

for the Oconee-1 PWR." LA-DR-83-3182 (no date), pp. 33. 34.

2.5. C.D. Fletcher. et. al.. "RELAP5 Thermal Hydraulic Analysis of

Pressurized Thermal Shock Sequences for the Oconee-1 Pressurized Water

Reactor." EGG-NSMD-6343, July 1983. p. 97.

2.6. "A Pressurized Thermal Shock Scenario Compatible RELAP5 Thermal-

Hydraulic Model of the Oconee-1 Steam and Power Conversion System

Main/Emergency Feedwater Trains." SAI #1-245-08-388-01, prepared for

Instrumentation and Controls Division. ORNL by Science Applications.

Incorporated. Oak Ridge. Tennessee. December 1982.

2.7. "Overview of Integrated Control System Modeling for the Pressurized

Thermal Shock Study." prepared for ORNL by Science Applications.

Incorporated. Oak Ridge. Tennessee. October 13. 1982.

2.8. A.F. McBride, letter to J.D. White. ORNL. "Oconee Interaction Analysis

- Incorporation of Duke Power Comments." May 10. 1983.

2.43

3.0 EVENT SEQUENCE ANALYSIS

T. J. Burns, Oak Ridge National Laboratory

R. Olson, Science Applications, Inc.

3.1 Introdnction

Tbe purpose of the event sequence development and analysis in this project

was to document the event sequences that could involve significant potential

for pressurized thermal shock (PTS), to select sequences with a range

of severities for detailed thermal-hydraulic analysis, and to estimate the

probability of occurrence of all sequences.

A straightforward application of event tree methods to the PTS problem

would result in an entirely unmanageable number of sequences, far more than

would result if core damage were being investigated, and far more than

could be studied with thermal-hydraulic analysis at any reasonable cost.

The event tree task thus used a modular approach. System state trees

were developed for the major plant systems independently of the transient

initiating events. These event trees were made to be applicable to

the various initiating events by incorporating "conditioning events," that

contain the proper system configuration (i.e., pressure, temperature) for

each initiating event. Human error or actions were coded into "operator

action trees" separately from the system state trees, and these trees were

used to modify the outcomes of the system state trees for each initiating

event, as appropriate.

The methodology is described in Section 3.2, the construction of the system

state trees is discussed in Section 3.3, and the quantification of the

3.1

trees is discussed in Section 3.4. The way in which the transients

were categorized for consideration of operator action is shown in Section

3.5, and the construction of the initiator-specific system state trees

is described in Section 3.6. The construction and quantification of the

operator action trees are described in Section 3.7.

3.2 Methodology

The representation of FTS transients using the "standard" event tree

formalism is extremely difficult because of the complexity inherent in

the PTS phenomena. The principal reason for this complexity is the

dependence of the consequences of PTS transients (the failure/non failure

of the pressure vessel) on the temperature history of the near-wall

primary coolant as well as the pressure. Thus, the timing of various

system actions during a transient can have a significant impact on the

consequences of the transient. A second complexity is related to the fact

that for FTS transients, the consequences may not be monotonic functions

of the principal transient parameters. Thus, intermediate values of the

parameters (e.g., valve positions) may result in more severe consequences

then either of the two extreme positions (i.e., fully open or fully

closed). Additionally, PTS transients are usually characterized by strong

interactions among thermal-hydraulic parameters, and these interactions

must be properly accounted for in any tree-type representation. Finally,

there is the question of operator actions and, more specifically, the

timing of operator actions. For some FTS-related transients, mitigating

actions by the operator are the only mechanism for preventing challenges

to the pressure vessel. However, successful mitigative action is dependent

3.2

on the time available for such action, which is, of course, dependent on

the specific transient.

Rather than try to incorporate all of the above effects into standard event

tree formalism, an alternate methodology was developed and used for this.

Two sets of trees were developed to represent FTS-related transients, a

group of system state trees and a set of operator action trees. The system

state trees were designed to permit the ready identification of the possible

system configurations and to assist in the specification of the transient

sequences to be subjected to detailed thermal-hydraulic moduling and

calculation. The rationale for separate operator action trees (as opposed

to incorporating operator actions into an event tree) is two fold; (1) the

need to consider various timing options for specified operator actions,

and (2) the recognition that operator action under FTS conditions may

require cognitive processes in addition to purely mechanistic actions.

The separation of the operator actions analysis from the system response

analysis facilitates both objectives. It should be emphasized that the use

of separate trees for the system and operator responses does not imply that

they are independent conceptually. They should be viewed as parallel trees

(in time) with a high level of interaction.

The system state trees were developed on a functional basis. Since

FTS transients typically involve a significant number of systems and

subsystems, it was felt that a functional level approach would serve to

clarify both the reasons for the modeling as well as the interrelationship

between the systems. The four functional groupings used in this study

were:

3.3

1. Secondary pressnre control (steam lines, tnrbine stop valves, tnrbine

bypass valves, and steam relief valves),

2. Steam generator feedwater snpply (main feedwater and emergency feedwater

systems),

3. Primary loop coolant flow (reactor coolant pnmps, bigb-pressnre

injection, core flood tanks, low-pressnre injection, and vent valves),

and

4. Primary loop pressnre control (PORV, safety relief valves, pressnrizer

sprays and beaters).

Tbese fonr fnnctional gronpings were fonnd to be inclnsive enongb to

encompass tbe transients tbat resnlt in low flnid temperatnres conpled witb

(or followed by) bigb primary system pressnre.

To facilitate tbe initial representation of PTS-related transients on

tbe system state trees, two distinct types of events are considered:

system response events, and conditioning events. Tbe majority of tbe

events represent system responses to tbe transient in qnestion. In many

cases tbe system response events include representation beyond tbe binary

success and failure branches found on most standard event trees. Sucb

a representation was felt to be necessary to distinguish between system

states sucb as "one of two valves fails" and "two of two valves fail."

Tbe conditioning events represent tbermal-bydraulic states and serve a

dual purpose; they restrict tbe number of potential end-states for a

given system state tree, and they permit tbe coupling between tbe various

functional system state trees (due to tbe tbermal-bydraulic interactions)

3.4

to be represented. An example of a conditioning event is the turbine

stop valve status (open or closed) dependent on the plant status (at power

or at hot standby). The conditioning event terminology is used since

subsequent system responses are considered conditional on the thermal-

hydraulic parameters that comprise the conditioning event description.

Initially, the system state trees are considered to be time-independent.

From such a perspective, the end-states can be viewed as an asymptotic

distribution of possible system configuration. It must be noted that such

an interpretation implicitly contains three assumptions:

1. No operator action to mitigate (or exacerbate) the transient,

2. Infinite capacities for reservoirs involved in the transient (e.g., the

borated water storage tank), and

3. No thermal-hydraulic limitations to the proper functioning of operating

systems (e.g., the RC pumps do not cavitate under low pressure or two-

phase flow conditions).

In spite of the unrealistic nature of these assumptions, the system state

trees represent an extremely useful and instructive initial categorization

of the extent of FTS challenge inherent in the systems. In particular,

the subsequent interpretation of the trees as time-dependent, coupled

with thermal-hydraulic analysis, permits the identification of inherent

system limitations that serve to mitigate the severity of FTS transients.

Moreover, analysis of a few of the asymptotic cases from both a thermal-

hydraulic and fracture mechanics perspective allowed the estimation of

reference time frames within which operator action is effective. This

3.5

information is necessary to quantify the operator action trees for each

transient because the probability of operator error is related to the time

available for the action. The use of the asymptotic end-state perspective

also permits a unique interpretation of the operator actions. The actions

of the reactor operator(s) can be viewed as "switching" a transient from

"on track" to an alternate asymptotic configuration. And, for most of the

envisioned PTS transients, the end-state ultimately switched to does not

require the assumptions listed above.

In general, an operator action tree must be constructed for each unique

asymptotic end-state. The operator action trees are based on the premise

that the transient is proceeding towards the specified asymptotic end-

state, and they detail the significant action/non action available to the

operator. In reality, some operator actions, particularly those involving

long time displays, may be precluded by the failure to hold of one of

the other two thermal-hydraulic assumptions. However, the initial operator

action trees were constructed without regard to this effect.

The overall system state tree/operator action tree methodology can be

suaimarized as a seven-step procedure:

1. The identification of the relevant conditioning events for each of

the four functional groupings (secondary pressure control, feedwater,

primary coolant flow, and primary pressure control);

2. The construction of generic system state trees for each functional

group that incorporate the conditioning events and their appropriate

system/subsystem responses;

3.6

3. The merging of the system state trees for each of the four functional

groupings into a single system state tree for a specific transient

initiator:

4. The quantification of the branch probabilities based on the appropriate

conditioning events;

5. The pruning of the overall system state tree based on frequency (this

study utilized l.OE-06 as a ncminal cutoff), physical impossibility,

and engineering judgment regarding the conditioning event;

6. The construction of an operator action tree for the remaining

significant end-states;

7. The quantification of each operator action tree to determine the

overall frequency of the various end-states including the effects of

operator actions.

3.3 Construction of the Oconee-1 Svstem State Trees

3.3.1 Secondary Pressure Control System State Trees

Since an excessive steam demand can result in a potential over cooling

transient, the secondary-side pressure-control system is a requisite part

of any PTS analysis. The mechanisms for control of the secondary-side

pressure for the Oconee-1 plant include the turbine stop valves, the turbine

governing valves, the secondary steam relief valves, and the turbine bypass

system. The Oconee-1 plant has four turbine stop valves (TSVs) (two on

each steam line) linked to a common header upstream of the four governing

3.7

valves. Each steam line has four pairs of safety valves which open sequen­

tially. Finally, two pairs of turbine b3rpass valves (one pair per steam

line) permit the dumping of steam directly to the condenser and serve as a

pressure-control mechanism for each steam line.

In constructing the secondary-side system state trees, it is necessary to

develop the state tree for each steam line separately so that possible

interactions can be accommodated. For the purposes of this discussion,

the response of steam line B is assumed to be conditioned on the system

state of steam line A. Since the Oconee-1 plant is symmetrical in this

regard, the corollary description is straightforward. Additionally, in

constructing the system state tree for steam line A, an attempt has been

made to order the events to maintain chronological order where possible.

The status of the turbine stop valves and their response to a control

signal are the most important considerations in describing the response

of the secondary pressure-control system. For most areas of PTS concern

(i.e., steam line breaks upstream of the TSV), the relevant question is

whether the TSVs on steam line A close in response to a turbine trip

signal, thereby isolating steam line A from both the turbine and steam

line B, preventing a blowdown of both steam generators. To model this

response, a binary event branch is assumed, with the success branch defined

as the closure of both TSVs. Additionally, this event branch point also

serves as a convenient means for treating the status of the TSVs where

it is specified by the initial conditions (e.g., closed at hot standby).

This knowledge is incorporated into the quantification process by setting

the success branch probability equal to 1. Finally, transients can be

3.8

postnlated wherein the relevant PTS question is not whether steam line A is

isolated from steam line B but whether either one or both are isolated

from the turbine itself. For this case, the relevant failure branch is

interpreted as the failure of at least one TSV to close on demand and

the failure of at least one turbine governing valve to close on a turbine

trip. However, unless specifically noted in the discussion, the initial

definition of this event will be used.

If the turbine stop valves on steam line A successfully close (or are

closed), the response of the remaining pressure control subsystems becomes

relevant to the FTS problem. It is assumed that if the TSVs do not meet

the success criterion, there will be no demand for any additional secondary

pressure relief.

Given success of the TSV branch, a conditioning event based on the

maximum steam line pressure occurring in steam line A is introduced. This

conditioning event is used as a demand switch to identify which of the

remaining two secondary pressure control systems are demanded, the safety

relief valves (SBYs) or the turbine bypass valves (TBVs). Three relevant

states are employed: State 0 - maximum steam line pressure greater than

1050 psi (both SRVs and TBVs demanded); State 1 - pressure between 935 and

1050 psi (only TBVs) demanded); and State 2 - maximum pressure is less than

935 psi (neither demanded). Generally, only one branch is applicable to

a given transient, and the appropriate branch is determined from thermal-

hydraulic analyses. However, as will be apparent in the discussion of

the initiator-specific event trees, using such conditioning event switches

greatly facilitates the construction of the initiator-specific event trees.

3.9

The operability of the turbine bypass systeai is the next event considered

in developing the secondary pressure control system state tree. Given

a demand signal, three TBV response states are defined. For the first

(State 0), the TBVs on steam line A function as designed to control the

secondary pressure, opening on high pressure and modulating to maintain

desired pressure. The first failure branch (State 1) is defined as at

least one TBV's failure to modulate back from its maximum ojwn position.

For this state the possibility of the stuck-open TBV's reclosing at some

point later in the transient is neglected. State 2 is defined as a failure

of both TBVs to open on demand.

The next response of concern to the FTS analysis is whether, given that at

least one SRV is demanded, the valve opens. For this analysis, it is assumed

that if the SKVs are demanded, they will open as designed, hence a specific

branch relative to the opening of the SRVs is not employed. The subsidary

question of whether the SRVs, having opened as designed reseat when the

steam line pressure is reduced, is represented by a separate event, which

can be integrated as an induced steam line break. For the purposes of this

analysis, the success branch is defined as all SRVs, which have opened on

demand, reseating at pressures greater than 1000 psi. The failure branch

is defined as at least one S R V s failure to reseat at a pressure > 1000

psi. Although the possibility exists that the malfunctioning valve may

reseat at a lower pressure than the design value, it is assumed that the

failure is in effect for the length of the transient.

Figure 3.1 depicts the system state tree that results from combining the

four secondary-side pressure-control events outlined above. Additionally,

3.10

TSVS fl MRX SL R RLL TBV RLL SSRV SEQUENCECLOSE PRESSURE MODULRTE? RESERT NUMBER

YES

YES

P > 1050

JES.NO

FAIL OPEN

FAIL CLOSED

955 < P < 1050

P < 955

SPflOl

SPfl02

SPR03

SPR04

SPR05

SPR06

SPR07

SPR08

SPR09

SPRIO

SPRll

SPR12'

Figure 3.1 Secondary pressure control (SL A) system state tree; initiator: unspecified.

for convenience. Table 3.1 presents an abbreviated version of the

success/failure criteria for each branch.

The system state tree for steam line B is constructed in an analogous

fashion to that of A with one notable exception, that of the conditional

probability of failure of the pressure-control components of steam line

B given the failure of the same or related components of steam line A.

Structurally, the system state tree for steam line B is identical to that

for steam line A. Hovever, as vill be discussed in the following section,

the assumption of a degree of commonality between components actually

results in multiple system state trees for B conditioned on the system

state of steam line A. At least five distinct categories of end-states

can be distinguished: nominal operation (sequences SPAOl, OS, 07, 09, 11),

open TBVs (SPA 03. 08), SKV failures (SPA02, 06, 10), TSV failures (SPA12),

and multiple failures (SPA04). Each requires that the generic steam line

B system state tree be quantified using conditional probabilities. The

generic secondary pressure control system state tree for steam line B is

given as Figure 3.2.

3.3.2 Feedwater System State Trees

A second potential contributor to a PTS transient is the overall feedwater

supply system. Excessive feedwater (via either the main feedwater supply

system, the emergency feedwater supply system, or both) can result in a

rapid cooldown of the primary system and lead to a potential PTS condition.

The main feedwater system of the Oconee-1 plant consists of two main

feedwater pumps, three condensate booster pumps, and three hotwell pumps.

Main feedwater (MFW) flow is typically controlled via a feedwater control

3 . 1 2

Table 3.1. Secondary pressure control system states

1. A. EVENT/STATE - Turbine stop valves on steam line A close.B. ABBREV - TSVS A CLOSEC. EVENT TTFG: System ResponseD. m N C H DESCRIPTION:

STATE 0: Botb turbine stop valves on steam line A close.STATE 1: At least one TSV on steam line A fails to close.

2. A. EVENT/STATE - Maximum steam line pressure is vitbin designatedlimits.

B. ABBREV - MAX SL PRESSUREC. EVENT ITPE: ConditioningD. BRANCH DESCRIPTION:

STATE 0: Maximum secondary steam line pressure is 2 lOSO psi.(Demand to botb TBVs and SSRVs.)

STATE 1: Maximum secondary steam line pressure 2 935 Psi but^ 1050 psi. (Only TBVs demanded.)

STATE 2: Maximum secondary steam line pressure 2 935 psi.(No pressure relief demand.)

3. A. EVENT/STATE - Turbine bypass valves on steam line A modulate tomaintain steam line pressure.

B. ABBREV - ALL TBV MODULATEC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: Botb turbine bypass valves on steam line A modulate tomaintain proper steam line pressure.

STATE 1: At least one TBV fails to function properly resultingin a steam line pressure less tban tbe set point.

STATE 2: Botb TBVs fail to open on demand.4. A. EVENT/STATE - Secondary side relief valves reseat given pressure

reduction below tbeir reseat point.B. ABBREV - ALL SSRV RESEATC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: All secondary side relief valves on steam line A reseatgiven pressure reduction.

STATE 1: At least one SSRV fails to reseat.

3-13

RLL SPfl TSVS B MAX SL RLL TBV RLL SSRV SEQUENCESEQ CLOSE PRESSURE MODULRTE? RESERT NUMBER

U )

SBlOl

SB102

SB 103

SB 104

SB 105

SB 106

SB 107

SB 108

SB109

SBllO

SBlll

SB112

Figure 3.2 Secondary pressure control (SL B) system state tree; initiator: SPA sequence.

valve, although manual control is possible. The MFW pumps are in turn

controlled via the differential pressure across the MFW control valves.

The emergency feedwater (EFW) pumps (two motor-driven and one turbine-

driven) start on low-MFW pump discharge pressure. Emergency feedwater

flow, however, is controlled by the emergency feedwater control valves,

which respond to the steam generator (S6) level-sensing system.

Unlike the case for the secondary-side pressure-control state tree, no

single conditioning event can be used to simplify the feedwater system state

tree. For the feedwater system, three conditioning events are employed,

leading to a conditioning event tree. As in the previous section, the

conditioning events are included to permit the consideration of both normal

and off-normal responses. The relevent conditioning events used consist of

the availability of the main feedwater supply system, the transient-induced

MFW pump discharge pressure, and the response of the SG level control

system to the transient-induced thermal-hydraulic conditions.

The availability of the MFW system is included as a conditioning event to

account for those transients whose initiators disable the MFW system and

hence preclude any automatic response by the system. The principal example

of this type of event is a transient initiated by loss of MFW. The success

branch for this conditioning event is defined to be the normal operation

of the MFW system immediately following an initiating event. Failure is

defined as no MFW flow. This conditioning event also serves to screen

transients that begin from initial conditions where the MFW system is not

functioning or in operation.

3.15

Hie second conditioning event employed is a binary branch based on the MFW

pnmp discharge pressure. As noted above, the magnitude of the MFW pump

discharge pressure determines the demand for EFW pump actuation. Thus,

the second feedwater conditioning event is defined as the minimum MFW pump

discharge pressure induced by the transient. State 0 is defined as MFW

pump discharge pressure greater than 725 psi (no EFW demand signal), while

State 1 is taken to be a pressure less than 725 psi (EFW demanded).

The final conditioning event includes the response of the steam generator

level control system. Recognizing the fact that certain transients have

the potential for creating false signals in the SG level control system,

three relevant branches are defined. The first state (State 0) is one

in which the SG level control signals indicate a high-level condition in

at least one SG due to transient-induced phenomena. The second state

(State 1) is defined as the nominal response of the level control system

(i.e., the control signals accurately reflect the condition of the steam

generators). The remaining state (State 2) is defined as an indication

of a low-level condition in at least one SG due to the transient-induced

phenomena.

Combining these three conditioning events results in the feedwater

conditioning event tree depicted by Figure 3.3. It should be noted that the

high-MFW-pressure case with MFW unavailable has been eliminated because,

without the MFW pumps, the discharge pressure is limited by the shutoff

head of the condensate booster pumps.

The conditioning event branches give rise to nine feedwater system state

trees. However, since the nine trees have many events in common (differing

3.16

MFW SYS. flVfllLflBLE?

MFW LINE PRESSURE?

SG LEVEL SIGNRLS

SEQUENCENUMBER

HIGH FCEGI

> 725 NOMINAL FCEG2

LOW FCEG3YES

FCEG4

< 725 FCEG5

FCEG6

FCEG7

NO FCEG8

FCEG9

Figure 3.3 Feedwater conditioning event tree; initiator: unspecified.

only in the probability of individual branches), only the significant

differences will be called ont explicitly in this discussion.

Because the primary concern regarding the feedwater supply is that of

excessive feedwater relative to the heat source, the feedwater system trees

are constructed on the basis of an implied reduction of the heat source

(i.e., a reactor trip). The case of a malfunction resulting in excessive

feedwater for a constant heat source will be treated on an exceptional

basis later in the discussion. Within this context, the primary event of

concern is the success of MFW runback on demand. Four PTS-relevant runback

states are of concern: the runback is successful; it is unsuccessful in

a single SG resulting in excessive MFW to the SG; it is unsuccessful with

regard to both SGs (i.e., a double overfeed); and lastly, the attempted

runback results in the trip of the MFW pumps, which for most transients

is equivalent to the loss of MFW flow. State 0 is defined as a successful

runback wherein the MFW flow to each SG is modulated to maintain the

correct SG levels. State 1 is defined as an unsuccessful runback for a

single SG with an uncontrolled level increase. State 2 is defined as an

unsuccessful runback to each SG resulting in increasing levels, and State

3 is defined as the loss of both MFW pumps as a result of an attempted

runback.

The second system of interest concerns the steam generator protection

system installed at the Oconee-1 plant. This system is designed to trip

the MFW pumps if the level in either SG reaches 90% of the operating range.

This level is inferred from Ap sensors in each steam generator. Since

the 90% level is beyond the normal operational range, this event is only

3.18

relevant for those branches indicative of overfeeds. The success branch

is defined as the trip of both liFW pumps, given that the 90% level has

been reached, and the failure branch is defined as the failure to trip at

least one MFW pump, given that the 90% level has been reached.

In addition to the response of the system, the response of the

emergency feedwater system is also relevant to the PTS analyses. The first

response of interest is whether the EFW pumps start, given a demand for

EFW. The success branch, denoted by State 0, is defined as the start

of at least one (of three) EFW pumps. Two different failure states are

distinguished: State 1, failure of a manual start of the EFW pumps; and

State 2, failure of all EFW pumps to start due to the unavailability of

their emergency feedwater system. This distinction is made because the EFW

system can be manually restored, which will be considered in the operator

action trees.

The final system response concerns the potential for EFW overfeeds, given

the success of EFW pump actuation. Three possible flow-control branches

are distinguished. State 0 describes the condition whereby EFW flow to

both SGs is modulated to maintain the correct SG water level. For State 1,

the EFW flow to a single SG is greater than that required to maintain the

appropriate water level, and for State 2, the EFW flow is greater than that

required for water level maintenance to both SGs. Table 3.2 summarizes

the branch definition for all FW events.

Combining these four system responses under the assumptions of the

first feedwater conditioning event end-state (FCEOl)— i.e., MFW system

operational, MFW pump discharge pressure > 725 psia, and high SG level

3.19

Table 3.2. Feedwater system states

1. A. EVENT/STATE - MFW system is functioning.B. ABBREV - MFWS AVAILABLE?C. EVENT TTFE: ConditioningD. BRANCH DESCRIPTION:

STATE 0: At least one MFW pump remains in operation given tbeinitiator.

STATE 1: Neither MFWP is available. [Condensate system remainsavailable however.]

2. A. EVENT/STATE - Main feedwater line pressure within specified limits.B. ABBREV - MFW LINE PRESSURE?C. EVENT TYPE: ConditioningD. BRANCH DESCRIPTION:

STATE 0: MFW line pressure >. 725 psi.STATE 1: MFW line pressure ^ 725 psi.

3. A. EVENT/STATE - Apparent GS level signals induced by transients.B. ABBREV - SG LEVEL SIGNALSC. EVENT TYPE: ConditioningD. BRANCH DESCRIPTIONS:

STATE 0: SG level signals indicate high level (trip level) in atleast one SG due to transients-induced phenomena.

STATE 1: SG level signals accurately reflect the condition of theSGs.

STATE 2: SG level signals indicate low-level (override) in atleast one SG due to transient-induced phenomena.

4. A. EVENT/STATE - Main feedwater system runback state followinginitiator.

B. ABBREV - MFWS RUNBACE?C. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: BIFW system runback is successful, and the MFW flow to theSG is modulated to maintain the appropriate levels.

STATE 1: Runback is unsuccessful and results in an overfeed to 1flow to the other is modulated to maintain the SG. MFW maintains appropriate level in the unaffected SG.

STATE 2: Runback is unsuccessful and results in an overfeed toboth SGs.

STATE 3: Runback is unsuccessful and results in the MFW/condensatesystems being rendered inoperable temporarily.

5. A. EVENT/STATE - Main feedwater pumps trip on high steam generatorlevel.

B. ABBREV - MFW PUMPS HLSG TRIPC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: System trips both MFWP; given level set point is reachedin at least one SG.

STATE 1: System fails to trip; at least one MFWP given level setpoint is reached in at least one SG.

3.20

6. A. EVENT/STATE - Emergency feedvater pnmps start.B. ABBREV - EFVPs STARTC. EVENT TTFE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: At least one EFWP (of the two MDEFWP and 1 IDEFWP) startsupon demand.

STATE 1: No EFW pnmp starts dne to EFW pnmp controls being inmanna1.

STATE 2: No EFW pnmp starts dne to EFW system nnavailability.7. A. EVENT/STATE - Emergency feedwater flow to steam generators

controlled or SG level set point.B. ABBREV - EFW FLW CNTRL/LEVELC. EVENT TTFE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: EFW flow to botb SGs is nominal. Tbe EFW flow to eachSG is modnlated to maintain tbe appropriate SG level.

STATE 1: EFW flow to 1 SG is greater tban that required to maintainSG level. Flow to unaffected SG is modnlated to maintain tbe appropriate level.

STATE 2: EFW flow to botb SGs is no greater tban that required tomaintain SG level.

3 . 2 1

signals— ^yields tlie systeai state tree given in Figure 3.4. For this

system state tree, the EFW system is only demanded if the MFW pumps are

tripiied (either dne to high SG level or rnnbach difficulties). Similarly,

using the assumption of FC!E02, Figure 3.5 can be constructed. The major

differences in structure involve the EFW pump activation event of the

successful MFW runback branch. Figures 3.6 through 3.10 depict the system

state trees resulting from the remaining conditioning event assumptions.

3.3.3 Primary Loop Coolant Flow System State Trees

Whereas both the secondary'side pressure-control systems and the feedwater

supply systems influence the fluid conditions seen by the pressure vessel

indirectly (via the steam generator), the coolant flow patterns in the

primary loops directly impact pressure and temperature. Of concern to

the PTS analysis are both the normal primary coolant flow systems (i.e.,

the status of the reactor coolant pumps and the core vent valves) and the

emergency core cooling systems (ECCS). For the Oconee-1 plant, however,

the status of the reactor coolant pumps (RCPs) is governed by operator

action, so discussion of possible changes of state of the RCPs will be

deferred to the section on operator actions. Similarly, because of the

intimate connection between the status of the RCPs and the functioning

of the vent valves, discussion of the vent valve operation will also be

deferred. The remaining systems of concern are the ECC systems [the high-

pressure injection system (HPI), the core flood tanks, and the low-pressure

injection system (LPI)].

The HPI system is of concern primarily because of the system capability

to maintain a high RCS pressure or subsequently to repressurize to a

3.22

FW CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 1 RUN3RGK HLSG TRIP START CNTL/LEVEL NUMBER

su c cess fu l

K)U>

overfeed (J.SCi)

overfeed (2SG)

LOMFW

FSlOlFS102FS103FS104FS105FS106FS107FS108FS109FsnoFsniFS112FS113FSIHFS115FS116FS117FS118FS119FS12QFS121FS122FS123

Figure 3.4 Feedwater system state tree; initiator: FCE sequence 1.

FW CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 2 RUNBRCK HLSG TRIP STRRT CNTL/LEVEL NUMBER

N5

FS201FS202FS203FS204FS205FS206FS207FS208FS209FS210FS211FS212FS213FS214FS215FS216FS217FS218

Figure 3.5 Feedwater system state tree; initiator: FCE sequence 2.

FW CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 3 RUNBRCK HLSG TRIP START CNTL/LEVEL NUMBER

roU i

FS301PS302FS303FS304FS305FS306FS307FS308FS309FS310FS311FS312FS313FS314FS315FS316FS317FS318

Figure 3.6 Feedwater system state tree; initiator: FCE sequence 3.

rw CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 4 RUNBACK HLSG TRIP START CNTL/LEVEL NUMBER

N5O'

F 3 « l PS 402 FS403 PS 404 PS 405 F5406 PS 407 P3408 PS 409 FS410 FS411 PS412 PS413 PS414 F3415 PS416 P3417 PS418 FS419 PS420 PS 421 P 3422 PS423 PS 424 P3425 PS 426 PS 427 PS 428 FS429 PS430 PS431 PS 432 PS 433 PS434 FS435

Figure 3.7 Feedwater system state tree; initiator: FCE sequence 4,

FW CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 5 RUNBRCK HLSG TRIP STRRT CNTL/LEVEL NUMBER

U)

FS50]F3502F5503PS504FS505FS506F3507FS508FS509F551DFS511FS512FS513FS514FS515FS516FS517FS518F5519F5520FS521FS522FS523FS524FS525F352B

Figure 3.8 Feedwater system state tree; initiator: FCE sequence 5.

FW CE MFWS MFW PUMPS EFWPS EFW FLOW SEQUENCESEQ 6 RUNBRCK HLSG TRIP STRRT CNTL/LEVEL NUMBER

tsj00

FS601FS602FS603FS604FS605FS606F3607FS608FS609FS61QFS611FS612FS613FS614FS615FS616FS617FS618F5619FS620FS621FS622FS623F5624FS625F362B

Figure 3.9 Feedwater system state tree; initiator: FCE sequence 6.

ho

PW CE SEQ 7 - 9

EFWPSSTART

EPW PLOW C N TL /LE V E L

SEQUENCENUMBER

Fszni

F9,7n2

F9>7m

FS7H4

............. .... FS705

Figure 3.10 Feedwater system state tree; initiator: FCE sequences7, 8, and 9.

higli pressure. However, for certain transients (i.e., those with low RC

pressure), the temperature effects of the cold HPI fluid may also be an

important factor. The core flood tanks and LPI system are of concern for

the inverse reason. Although the pressure effect is inherently limited,

these systems have the capacity for replacing a large fraction of the

primary coolant inventory with "cold" fluid. Moreover, both of these

systems inject fluid directly into the downcomer, whereas the HP injection

point is 16 ft upstream from the cold leg nozzle.

Since the demand signals for the various ECC systems are based on primary

system pressure, the appropriate conditioning parameter is the minimum

reactor coolant system pressure reached during the transient. Four possible

discriminants are used: State 0 - minimum RC pressure > 1500 psi (no

ECCS demand); State 1 - RCS pressure between 610 and 1500 psi (only HPI

demanded); State 2 - RCS pressure between 200 and 610 psi (both HPI and CFT

demanded); and lastly. State 3 - RCS pressure less than 200 psi (all three

systems, HPI, LPI, and CFT, demanded). This conditioning event serves to

simplify the construction of the initiator trees by restricting the number

of event branches that must be considered.

Given a demand for the HPI system, the next system response of interest

is whether the system functions as designed. A binary branch is defined

for this event. The success state is defined as transfer of all three HPI

pumps to the injection mode and coolant delivery to the RCS. The failure

branch is defined as failure of all HPI pumps to deliver coolant, given a

demand. As noted in the above discussion, the principal PTS concern in the

ECC systems is the success state (i.e., the system functions as designed).

3.30

The failure of these systems to operate properly upon demand generally

reduces the severity of PTS phenomena. However, the failure branches are

included to account for the potential of operator error upon restoration

(i.e., overcompensation) because of the generally high reliability of these

systems.

The branch point regarding the core flood tanks is defined similarly. The

success state is defined as the discharge of at least one core flood tank

into the downcomer upon demand. The failure state is the failure of both

flood tanks to discharge. The LPI branch is also defined similarly to

the previous two branches. The success state is defined as at least one

LPI pump's operating and coolant being delivered to the downcomer. The

corresponding failure state is that no low-pressure injection occurs.

The system state tree comprising these four events is depicted in Figure

3.11. Table 3.3 summarizes the definitions of the four events.

3.3.4 Primary Pressure Control System State Tree

The PTS concern with the primary-system pressure-control systems (PORV and

RVs) is centered on the potential for the creation of loss-of-coolant

situations and hence the triggering of ECC systems (if not already running).

In particular, the relief valves serve as a mechanism for the removal of

heat energy directly from the primary loop.

The appropriate conditioning event for the primary pressure-control system

state tree is the extent of the demand for pressure relief as indicated

by the maximum RCS pressure attained in the primary loop during the course

of the transient. Three states are categorized. State 0 is defined as the

3 . 3 1

MINIMUM HP I CFT LPI SEQUENCERCS PRESS INITIflTED DISCHflRQE INITIRTED NUMBER

U5N5

P > 1500

610 < p < 1500

200 610

p < 200

ECCOl ECC02 ECC03 ECC04 ECC05 ECC06 ECC07 ECC08 ECC09 ECC 10 ECC 11 ECC 12 ECC 13 ECC 14 ECC 15 ECC 16 ECC 17 ECC 18 ECC 19

Figure 3.11 Primary loop ECCS system state tree; initiator: unspecified.

Table 3.3. Primary ECCS system state tree

1. A. EVENT/STATE - Minimxim reactor coolant system pressure is within specified limits.

B. ABBREV - MININDM RCS PRESSC. EVENT ITPE: ConditioningD. BRANCH DESCRIPTION:

STATE 0 STATE 1 STATE 2 STATE 3

Minimum RCS pressure 2. 1500 psiaMinimum RCS pressure 610 psiaMinimum RCS pressure 200 psiaMinimum RCS pressure 200 psia

2. A. EVENT/STATE - High-pressure injection system activates upondemand.

B. ABBREV - HPI INITIATEDC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTION:

STATE 0: High-pressure injection system injects into reactorcoolant system (at least one HPI pump transfers to injection mode).

STATE 1: No high-pressure injection.3. A. EVENT/STATE - Core flood tanks discharge inventory to reactor

coolant system.B. ABBREV - CFT DISCHARGEC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: Core flood tanks discharge upon demand.STATE 1: Core flood tanks fail to discharge upon demand.

4. A. EVENT/STATE - Low-pressure safety injection into reactor coolantsystem initiated.

B. ABBREV - LPI INITIATEDC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: Low-pressure injection occurs (at least one LP pumpoperates).

STATE 1: Low-pressure injection system fails to deliver coolingwater.

3.33

condition in which the mazimnm RCS pressure remains less than 2450 psi (the

nominal PORV set point) and hence there is no demand for pressure relief.

State 1 is defined as the condition in wich reactor coolant pressure is

between 2450 psi and 2500 psi (the SRV set point), so that only the PORV is

demanded. Finally. State 2 is defined as the maximum RCS pressure's being

greater than or equal to 2500 psi, so that both PORV and SRVs are demanded.

For those conditioning states wherein the PORV is demanded, the next

relevant event is the operability of the PORV. This is, in effect, a two

part event. The first is the actual functioning of the PORV represented

by a binary event in which the success state is that the PORV lifts upon

demand and the failure state is the failure of the PORV to open upon

demand. The second part of this event is a conditioning event related to

the status of the block valve downstream of the POV. This is included

as part of the system state tree, because, if closed, operation of the PORV

upon demand will not provide any pressure relief. Again, a binary branch

is used, with success defined as the block valve's being open and failure

by its being closed.

Given a sufficient pressure relief demand, the next event is the operation

of the safety relief valves. The relevent question is whether the relief

valves, having opened on demand, reseat when the primary pressure is

reduced. If this fails to occur, the plant experiences a transient-induced

loss-of-coolant event. The first reseat question concerns the SRVs, and

success is defined as the closure, upon pressure reduction, of all the SRVs

that have opened. Failure is defined as the failure of at least one SRV

3 . 3 4

to reseat. The implicit assumption contained in this analysis is that if

the SRVs are demanded, they mill open with a probability of 1.

The rationale for discriminating between a stnch-open PORV and a stnck-open

SRV is linked to the possible corrective operator actions. The former is

an isolable loss-of-coolant accident (LOCA), whereas the later is not.

These five events comprise the primary pressure control system state tree

depicted by Figure 3.12. Table 3.4 summarizes the branch definitions

specified in the above discussion.

3.4 Quantification of the Functional Svstem State Trees

One of the primary purposes for introducing the concept of a conditioning

event was to permit the quantification of each of the four functional

system state trees (secondary pressure control, feedwater supply, primary

ECC systems, and primary pressure control) separately. Once each is

quantified, the initiator-specific event trees are constructed by combining

the four functional trees into an overall system state tree and by selecting

the appropriate set of conditioning events for the given initiator. This

section discusses the numerical values used to quantify each of the four

functional system state trees.

Probability values were estimated, when possible, from operational

information, which was as close to Oconee-specific as possible. If Oconee-

specific information was available, then it was used. If this was not

the case, B&V-specific and finally PWR-specific operational information was

employed. Additional information was obtained from lEEE-SOO, the NREP

Generic Data Base screening values, as well as from other sources.

3.35

MAXIMUM PORV OPENS BLOK VALVE SRV PORV SEQUENCERCS PRESS OPEN RESEATS RESEATS NUMBER

COCTn

p < 2450

2^50 < D < 25 00

p > 2500

PPCOl PPC02 PPC03 PPC04 PPC05 PPC06 PPC07 PPC08 PPC09 PPCIO PPG 11 PPG 12 PPG 13 PPG 14 PPG15

Figure 3.12 Primary pressure control system state tree; initiator;unspecified.

Table 3.4. Prinary pressure control systen state tree

1. A. EVENT/STATE - Maximum reactor coolant system pressure is within specified limits.

B. ABBREV - MAXIMDM RCS PRESSC. EVENT TYPE: ConditioningD. BRANCH DESCRIPTION:

STATE 0 STATE 1 STATE 2

Maximum RCS pressure < 2450 psiaMaximum RCS pressure > 2450 psiaMaximum RCS pressure > 2500 psia

2. A. EVENT/STATE - Power operated relief valve opens, given RCS pressure> 2450 psi.

B. ABBREV - PORV OPENSC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTION:

STATE 0: PORV opens at 2450 psi to relief RCS pressure.STATE 1: PORV fails to open (fails closed).

3. A. EVENT/STATE - Block valve downstream of PORV is open.B. ABBREV - BLCK VALVE OPENC. EVENT TYPE: ConditioningD. BRANCH DESCRIPTIONS:

STATE 0: Block valve is initially open.STATE 1: Block valve is initially closed (PROV disabled).

4. A. EVENT/STATE - Safety relief valve reseats, given pressure reductionbelow reseat pressure.

B. ABBREV - SRV RESEATSC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: Safety relief valve reseats, given pressure reduction. STATE 1: Safety relief valve fails to reseat, given pressure

reduction.5. A. EVSn'/STATE - Powex^generated relief valve reseats, given pressure

reduction.B. ABBREV - PORV RESATSC. EVENT TYPE: System ResponseD. BRANCH DESCRIPTIONS:

STATE 0: Power operated relief valve reseats, given a sufficientpressure reduction.

STATE 1: PORV fails to reseat, given pressure reduction.

3,37

3.4.1 Qaantlfication of the Secondary Pressnre-Control System State Tree

3.4.1.1 Turbine Stop Valves on Main Steam Line (SL) A Close/Demand (TSVs

A Close)

STATE 0: P = 1.0 - 9.5E - 0.4 = 0.999 (l-P(State D )

STATE 1: Vith regard to the TSVs, all PVR licenses event reports

(LERs) were reviewed for turbine stop valve failures. In

only one event (NSIC 092449 at Turkey Point 3) was a total

failure of all turbine stop valves identified. However,

several instances of individual TSV failures to close on

turbine trip signal were identified. Based on these data,

an estimate for State 1 (at least one TSV fails to close)

of 9.5E-04 was used.

'3.4.1.2 All IBVs Modulate (Demand for Pressure Relief to Turbine Bypass

System Results in the Appropriate Configuration)

STATE 0: All IBVs on SL A modulate to maintain proper steam line

pressure.2

P = 1.0 - 5 P(STATE .) = .999 i=l ^

STATE 1: At least one TBV fails to modulate from its maximum open

position. Oconee Units 1 through 3 have never had an

individual failure of these valves to close during a general

shutdown (including non specific reactor trip) or startup.

Based on 1978-1980 operating experience, there have been

3.38

approximately 10 shutdowns and startups per plant year.

Assuming a bypass valve failure on the next shutdown, one

can calculate a bounding failure probability as:

1/[no. of observed demands + 11= l/[4 valves/plant) x (10 shutdowns + 10

startups/plant year) x (Oconee 1, 2, 3, lifetime through 1981) + 1]

= l/[4 X 20 X 24.2 yrs + 1]—4= 5 X 10 /demand/valve

Thus the probability of failure to open either of the two valves on steam_3line A is taken as 10 /Demand.

STATE 2: Both IBVs on steam line A fail to modulate on demand. The

analysis for State 1 is applicable to the first valve, and

the conditional probability of the second valve failure,

given that the first valve failed is taken to be 0.1, is -41.0 X 10 /Demand.

3.4.1.3 All SSSV Reseat (At Least One Secondary^Side Safety Valve Fails

to Reseat, Given All Eight Open and Subsequent Pressure Reduction)

STATE 0: [All SSSVs reseat on pressure reduction]

P = 1.0 - P(State j) = .92

STATE 1: [At least one SSRV fails to reseat upon pressure reduction

below the set point.] The probability of a single passive

safety valve failing to reseat is assumed to be 1.0 x _210 . Since each steam line has eight safety valves, the

_2probability is just 8 x 10

3.39

3.4.1.4 Modifications of Secondary Pressnre-Control Branches for SL B Due

to Conditioning Events/Steam Line A Events

Turbine Stop Valves on SL A Fail To Close

The only event relative to SL B assumed to be conditional on the closure

of the TSVs on SL A is the closure of the TSVs on SL B. A conditional

probability of failure of 0.1 is assumed in this case to include potential

common-course failure coupling.

STATE 0; P = 0.9

STATE 1: P = 0.1

Turbine Bypass Valves on SL A Fails to Modulate (Fails Open)

A conditional probability of 0.1 for the same failure mode on SL B is

assumed. The failure probability for the alternate failure mode is assumed

unaffected.2

STATE 0: P = 1- ^ P(State - 0 . 9i=l

STATE 1: P = 1.0 x lO"^

STATE 2: P = 1.0 x 10“^

Turbine Bypass Valves on SL A Fail Closed

A conditional probability of 0.1 for the same failure mode on SL B is

assumed. The failure probability for the alternate failure mode is assumed

unaffected.

3.40

2STATE 0: P = 1- J P(State - 0 . 9

i=l

STATE 1: P = 1.0 x 10“^

STATE 2: P = 1.0 x 10 ^

Secondary Side Safety Valves on SL A Fail to Reseat

A conditional probability (attributable to identical valves, maintenance

operations, calibration, etc.) of 0.1 is assumed.

STATE 0: P = 9.0 x lO"^

STATE 1; P = 1.0 x 10“^

Using these assumptions, the overall secondary pressure control system

state tree given by Figure 3.13 was constructed.

3.4.2 Quantification of the Feedwater System State Trees

The quantification of the feedwater system state trees will be discussed

relative to the following set of conditioning parameters:

a. MFW pumps are running,

b. MFW line pressure remains greater than 725 psia as long as

the MFW pumps operate, and

c. The apparent SG level signals are nominally correct.

This set of conditions corresponds to feedwater conditioning event end-

state FOS 02 on Figure 3.3.

3 . 4 1

3.4.2.1 NFWS Runback (Main Feedwater Systea Rnnback Results in a Given

Configuration)

STATE 0: Rnnback of MFW is successful.3

P = 1.0 - 5 State . i=l

STATE 1: Rnnback is unsuccessful; overfeed to either SG. "The

Oconee Pressurized Thermal Shock Evaluation" (DPC-RS-lOGl,

January 1982) identifies four failures to rnnback following

a reactor trip:

Unit 2, September 17, 1974

Unit 2, April 30. 1974

Unit 2, January 30, 1980

Unit 3, March 14, 1980

During the time period considered in the Oconee study

(24 plant-years), approximately 144 reactor trips occurred.

This results in a failure to rnnback of roughly 4/144 >= 2.8_2- 10 /demand.

STATE 2: Rnnback is unsuccessful, resulting in an overfeed to both

SGs. Since a detailed failure analysis was not done for

this branch, it is calculated by assuming a conditional

probability of 0.1 for the second SG. That is, the

probability of an overfeed in the second steam generator

given an overfeed in the first *= 0.1. Thus, the probability

3.42

" w rCLOSE m SLAPFESBURE rsrwMOXtflrE? ncrswfESEftt TsrrCLOSE IHRKILSI PWSSURE McxxiLfrrE?icrm— \mmttBSERT I (/RY) SMUEf g "NUdGER

_ 8.5X10'' SPCOOOl6.5K10‘’ SPC00027.7* 10’’ SPC00035.9x10'’ SPC0004

_ 7.7x10'’ SPC00055.9x10'' SPC00069.2x10'' SPC00078.3x10'* SPC00087.7x10'* SPC00095.9x10'* SPCOOlO9.2x10'' SPCOOl17.9x10'* SPC00126.5x10'' SPCOOl3l.-txlO'* SPCOOl45.9x10'* SPCOOl51.3x10'* SPCOOl65.9x10'* SPCOOl71.3x10'* SPCOOl88.0X10'* SPCOOl97.2x10'* SPC00205.9x10'* SPC00211.3x10'* SPC00228.0x10'' SPC0023B.OxlO"* SPC00247.7x10'* SPC00255.9x10'* SPC00268.5x10'* SPC00276.5x10'* SPC00288.5x10'* SPC00296.5x10'* SPC00308.3x10'* SPC00319.2x10'* SPC00328.5X10'* SPC00336.3x10'* SPCC0349.2x10'* SPC00357.9x10'’ SPC003B5.9x10'* SPC00371.3x10"* SPC00386.5x10'* SPC00391.4x10'* SPC00406.5x10'* SPC00411.4x10"* SPC00427.2x10"* SPC00438.0x10"* SPC00446.5x10"* SPC00451.4x10"* SPC00468.0x10"* SPC00476.8x10"* SPC00487.7x10"* SPC00495.9x10"* SPCOQ508.5X10'* SPC00516.5x10'* SPC00528.5x10"* SPC00536.5x10"' SPC00548.3x10'* SPCD0559.2x10"* SPC00568.5x10'* SPC00576.5x10"' SPC00589.2x10"* SPC00597.9x10"* SPC00605.9x10"* SPC00611.3x10'* SPC00626.5x10"* SPC00631.4x10"* SPC00646.5x10"' SPC00651.4xl0' SPC00667.2x10"* SPC00678.0x10"* SPC00686.5x10"' SPC00691.4x10"' SPC00708.0x10'* SPC00716.8x10'* SPC00729.3x10 ‘ SPC00737.1X10"' SPC00748.3x10"* SPC00756.4x10"* SPC007B8.3x10"* SPC00776.4x10"* SPC007810.0x10 'SPC00799.0x10"* SPC00808.3x10"* SPC00816.4x10"* SPC008210.0X10 'SPC00838.5x10"* SPC00848.3x10"* SPC00856.4x10"* SPC00869.3x10"* SPC00877.1x10"* SPC00889.3x10"* SFC00897.1x10"* SPC00909.0x10'* SPC0091lO.OxlO*’SPC0092

_ 9.3x10"* SPC00937.1x10'* SPC009410.OHIO 'SPC00958.5x10^ SPC00967.7»10 SPC00975.9x10"* SPC0098

_ 8.5x10"* SPC0099_ 6.5x10"* SPCOlOO

8.5x10"* SPCOlOl6.5x10"' SPC01028.3x10"* SPC01039.2x10"* SPC01048.5x10"* SPC01056.5x10"' SPCOlOB9.2x10"* SPC01077.9x10"* SPCOlOB5.9x10"* SPC01091.3x10"* SPCOllO6.5x10"* SPCOlll1.4x10"* SPC01126.5x10"' SPC0U31.4x10"' SPC01147.2x10"* SPC01I58.0x10"* SPC01166.5x10"' SPC01171.4x10"' SPC0U88.0x10"* SPC01196.8X10"* SPC01209.3x10"' SPC01217.1x10"' SPC01228.3x10"* SPC01236.4x10"* SPC01248.3x10"* SPCD1256.4x10"* SPC0126

_ 10.0x10 'SPC01279.0x10"* SPC01288.3x10"* SPC01296.4x10"* SPC013010.0x10 '5PC01318.5x10"* SPC0132

_ 7.9x10"’ SPC01336.1x10"' SPC01347.1x10"' SPC01355.5x10"* SPC013B7.1x10"* SPC01375.5x10"* SFC01388.5x10"* SPC01397.7x10"' SPC01407.1x10"* SPC01415.5x10"' SPC01428.5x10 * SPC01439.5x10"* SPC0144

Figure 3.13 Secondary pressure control system state tree.

-2of this branch is given by 1.4 z 10 x 0.1 x 2 conbination

= 2.8 X 10"^.

STATE 3: Rnnback is nnsnccessfnl, resulting in a trip of the MFW

pumps. NDREG-0560 identifies five events at B6W plants

(through April 4, 1979, the date of IE Bulletin 79-05A) in

which feedwater was lost subsequent to a reactor trip. If

the Oconee-1 trip rate is assumed to be a typical value

for B6W plants (6 trips/year x 30.18 years of operation =

181 trips), this results in a probability of 5/181 = 2.8

This estimate does not include instrument bus failures that

result in a simultaneous reactor trip and a loss of MFW. P

= 2.8 X 10"^.

3.4.2.2 MFW Pumps HL6S Trip (Failure of the High Steam Generator Signal

to Trip Both MFW Pumps Given on Overfeed)

This trip circuit is tested yearly. Assuming a general instrumentation

failure rate of l.OE - 06/h (lEEE-SOO) results in a failure probability of-3l.OE - 06 X 8760 x 0.5 = 4.4 x 10 for the SG experiencing the overfeed.

This estimate is appropriate for those branches involving overfeeds to a

single SG. For the case of a high-level trip failure, given a double

overfeed, an alternate estimate must be made. Each SG has a separate

trip system; however, all signals (from either generator) use a common

relay. Thus, for branches involving a double overfeed, a value of 1.0 x—410 /demand (NPRDS value for relays) is assumed.

STATE 0: [High level protection system trips both MFW pumps]

3.44

P = 1 - P(State = .996

STATE 1: [High level protection system fails to trip at least 1 MFW

pump]

Pj = 4 X 10~^

3.4.2.3 EFW Pumps Start (Failure of All EFW Pumps to Start on Demand)

STATE 0: [At least one EFW pump starts on demand.]2

= 1 - 3 P(State .) = .993i=l

STATE 1: [Failure of EFW pumps to start on demand - system in manual

control.] The EFW system is assumed to be in manual control

(i.e., for testing maintenance, etc.) approximately 4 h/mo.

This results in a probability to start automatically on

demand of 4/(30 x 24) = 5.6 x IC"^ P = 5.6 x 10“^.

STATE 2: [Failure of EFW pumps to start on demand - system is

unavailable.] NDRE6/CR-2497 identified emergency feedwater-3failures on demand. This value was 1.1 x 10 , but it

included credit for short-term rectification. Excluding the

possibility of rectification (to be included in the operator_3action trees), the observed value was 1.4 x 10 /demand.

Oconee observed EFW unavailabilities at the pump level (in

1980 and 1981) are

Oconee Unavailabilitv Date

1 turbine pump 5/80

3.45

2 turbine pump 4/81

3 turbine pump 11/80

1 turbine pump 6/81

3 motor-driven pump 5/81

2 motor-driven pump 3/81

2 turbine pump 5/81

For the 17-mo period between May 1980 and September 1981,

there were seven unavailabilities, which results in an

unavailability per pump of 7/(1 test [demand]/mo x 17 mo

X 3 pumps/plant x 3 plants) = 0.05/demand. With only

one pump required for success, one can derive a system

failure probability of 0.05 (failure of first pump) X 0.3

(failure of third, given failure of first and second) = 1.5_3

X 10 /demand. This is consistent with the NDREG/CR-2497_3value of 1.4 X 10 /demand.

3.4.2.4 EFW Flow Q4TL/Level (Failure to Modulate EFW Flow to the SGs to

Maintain SG Water Level)

STATE 0: [EFW flow is modulated to maintain appropriate levels in

both SGs.)

P = 1.0 - 5 P(State .)i=l ‘

STATE 1: [EFW flow is excessive to 1 SG.] The EFW level circuit

consists of a level transmitter on each steam generator, an

associated E/P converter, and flow control valve. Additional

3.46

instrumentation is provided to change the SG level based

on whether or not the RCPs are operating. An alternate

level control channel is provided in the event power is lost

to the operating channel. It is assnmed that accessible

instrumentation is tested monthly and that the level changes

during operation can be cross-checked among the SG operating

and startup range level indications. Based on this, one can

roughly estimate the probability of overfill on initiation

as the probability of tranmitter failure or converter

failure or valve failure (10 ^/h x 720 h (level controllers,

IEEE-500) + 1 X 10 ^/demand (valve failure, WASH-1400) =_31.7 X 10 /demand for a specified generator. This gives an

estimate for either steam generator of 3.4E-03.

3.4.3 Probability Modifications Required for Off-Normal Situations

3.4.3.1 Apparent SG Level Signals Indicate High Level

HFWS Runback: No modification

For a normal runback (e.g., following reactor trip close to full power),

the SGs initially contain more inventory than is required. Thus, it is

assumed that the integrated control system (ICS) perceives this situation

as normal.

MFW Pumps EQ.SG Trip: No Modification

The probability of the SG protection system functioning is assumed

independent of the reading. The net effect of these two assumptions

3.47

however is that trip of the MFW ptimps becomes the most likely branch given

the conditioning event.

EFW Pnmps Start: No Modification

EFW Flow CNTL/Level: No Modifications

Although the same phenomena which produce the apparent high SG level

signals provided to the ICS will likely affect the EFW flow control system,

the phenomena are assumed to he of short duration. Since this system does

not involve trips, normal operation will be recovered when the phenomenon

ceases.

3.4.3.2 Apparent SG Level Signals Indicate Low Level

MFWS Runback

The assumption inherent in this conditioning event is that the SG phenomena

will result in a low-level that will which will override the runback to

the affected steam generator and will, in effect, overfeed the generator.

STATE 0: Given a low SG level control signal in the affected SG, it

is assumed that the probability of a normal runback is 0.0.3

STATE 1: P = 1.0 - J P(State .) = 0.96i=l ^

STATE 2: The probability of an overfeed to a second generator is

assumed to be the probability of a single SG overfeed on_2attempted runback, which is equal to 1.4 x 10

3.48

STATE 3: The probability of a loss of the MFWP on the attempted

rnnback is assnmed to be nnchanged by this conditioning_2event and thns eqnals 2.8 x 10

MFW Pnmps HLSG Trip

Since the SG high-level (HL) protection signals are based on the same type

of sensors as the rnnback signals (Ap sensors), it is likely that, at least

for the dnration of the apparent low-level signals, the HL trip system

will be inoperative. Thns, for the branch involving a single overfeed,

the failnre probability of the HL trip system is assnmed to be 1. However,

for the case of a donble overfeed, the nnaffected SGs protection system_3will fnnction. For this case, a failnre probability of 4.4 x 10 (the

same valne nsed for a single protection circnit) is assnmed.

EFW Pnmps Start (No Modifications)

EFW Flow (!NTL/Level

Again, the same phenomena which affect the MFW control system will affect

the EFW flow control system. Thns, the EFW to the affected SG will

likely be excessive for the dnration of the phenomenon. It is assnmed that

this is of short dnration, and since no trips are involved, continned EFW

overfeed wonld reqnire a system failnre. Hence, the branch probabilities

assigned in the reference case are nsed.

Using these assnmptions, the overall feedwater snpply system state tree

given by Fignre 3.14 was constrncted.

3.49

■'tnmr g .....

u io

...................... S.'i-JO’’ fri 8051Tii 805S........... ..........

.............. a.S-K:'’ >'fi 0053in"’ Hi 80331

i.rivjo'* FB 80S3S<;.!><! o'’ F'3 ooirn0. a«:o'’ m 80333'

............... < .7k:o'’ Fil 80333;................ 3,3xiCj'* PW 5033S

PW 5038............. .............. ........ :l :)x yn 0031.. ......... i r yn 5032

7. iix-iO'* •'■■4 0033............ r'H 5038

0, axis'’ !'« 5038uaxiB '’ r« 003 S

axis'* •■11 5;317................... 0 ,»x i3 '’ m O’Oia

................. ixSxiO'* r,i d s is.................. . a. /'xia"' r,1 8820

a .a x o i’’ fH ••821l.SxiO'’3. SaiJO'’ n'i ■ias:5

..................... S.-ixjO'’ 2034

................ . 3 .sx te '' 5335:

..................... Oi-; 5335

..................... 2 ,«xi0 '’ m 5337

..................... '.QXiO'’ ri'i 5333

..................... ■.S.'jxJB'’ m 0333

...................... i.iixJC'’ rw 00^3S.XMlii’’ • m 0331

....... mO.'ixin'’ ■ r'K' S3:i 1i.P.-xtc'’ C3Ho.sxiO''' 33;«i.O.ilxiC'’ fu ?3;;3

............. ,.,,.. S,5xJij'* rw'3337...................... x, 7x (f)'* m Q30S..........:.......... ii.SxjC’' fvi 3303........... :......... n>i 33'13

... x.Sxif!"’ m 33^1CiS

.......... 0,0 m 03^5. ■

........... ..........;: 0 ,0 m "03-<4 ■0.0 rw 03' 5' '

......... ......:... 0 .0 m- 53 * 30 ,0 m 33^7

................ . SiOxse"’ rn 03-J3 ■I....,...,:.!....:. i,0i><3o'’ i ■■'W ■03• 3 :^......,....... . 0,0i*30'* m OOS3':'............. . i i ix jo '’ rw oos-i.................. 0’ ,S"30'’ 7W'035a'.. i,sx)i5'* rw;''s353. '..........OiOXJO'’ •rw 033i, ..... . .iOSOjcd' m 33S5

....... 0,0x30'’SiJixJO'’'- m 3357i.BMtO'O 'm'.C303'

................ 3,SxiQ'* Bi . 0353

..................... s . rwiO'’ B 3303

................ l.gx iii'’ B ' 1535!0. Ox'-!"’ f'w ■S.O xii:’ fw 535;5i.S x tn ’’ B 53&a. i Kin"’ rw 53$57,0x10'' fw 53S3

i 4 . (K10' fw QG&7i . . ...................... ^.Ox;,!' fW' 03SS ■U - .... 5.9»3£i*

.................... o.oxm'*B 03S3

0373..................... ■3,;'x33:'’ f'3 0371

O.S.xiO'’ i'U 0373...................... i.i-x io '’ l'3 0377

................... ;?.,3-xi!3'’ IB 03741.7x13'* B Q373 ■

o. ix'iOi'’ B •1375..................... ) . ox.i.a’' f'rt UCJ77

fi. SkTO'' B; 5373t . 7x:n'' B; 53?3■7. 0x10"’ m 03S3

B 03-21a.oxoi"*■7.0X10'* B 0335

..................... I.RX’O'’ B 0335

..................... 3> ■ixis'' rB 3-:?3-37. axis'’ IB 3I1334. 7X113'” ■B 35S3

] 3,0x10'“ B 3037] 1,0x10'’ P4 3-388[ •,.0x10'” TH 3333

3. OXIO’ rn 35S30,7x;0'' B 3031

.................... .ii,8»;ct'* Yri im 2...................... !,ti»:o'’ I'li 0333'

...... 0,»"3C'’0.7-xlf!'*

03:HB 0053

I>6x'i0'’ B ' 0003! ................... 9,3x:sfi'' B 00071 ...................... S.3*7!i''’ B U0S3: B 5330

.3.0x10'** B 5300__ _____ 8,7x30'’ 7H 0101

• ...................... 0,x»3C'’ m 0103i .................... 1,H»iO'* B 0153: ,O..Sxifl'’ B 0154

..................... 1, axis'* B 0103B - 0:105

i B 5307Bl 530>3

..................... i,;'»30'* rn 0103, .................. ,. a.swiij** IB 0110

0.7x10'’ IB 0113:.......... _ XvOxiCi'’. . . . . . . .. .. •l.ixICl” ■B Oil 1:

1 ............. .. 8<oci' •B 01121 ................ . . s'. OxlCi'’* Bi 5315j ____ 2.3X10'’ BJ 5314

..................... 2. RxiO'* B CHS

..................... 0<?x;t3'” B 0110

..................... 2.Sxi!3'" IB 0117t.Sxin '’ B 01133,.sxin'*“ B 0U 3

................. . ;:,8xiCi'’ B 0330

..................... 8 .7«lCi'* B 3131

i........................................ 3.8X10'’..................... 1 .8X10'’..................... O.lixiiS'*

B G132 B 0123 IB 0157

fl.i! B 015Sfi, n B 015S0. n B 0337

B 01300. 0..................... Ci, 0 .B £1330

...............0 .0 B £13'.}il0.11 7>3 3-3 310.11 ryS 03 330 .0 B 03350 .0 B 0:34

.,,................. 5,Sxi.3'* B 0135

..................... I.Sxir.l'’ B 0136

..................... i3,Sx1:3” B 013^

..................... 0,4X10'’ IB 0-!,361 ,ax is'’ B 0130i.axirt'* B 014:3

...................... i!,'JX3Cl'* IB OHl •

...................... ;,1>x30'' B £l:4:i7 . Ox 10'* B 0343

..... .............. 1,8x10'' B 0144..................... B, ixKi” IB 0140..................... i.ttxin'' IB 33146

B, ■ xin B 01-4? rn 0148.2 . xxio"*

.................... .0 . fixio'’ m 0143................. a.SKic'* B OBI

X. 7x10'’ B 01013.0x10'’ B oio:i1 .0x10'* B 0353'3,8x10'’ B 0354

..................... if, 8x11! ' B 0365

..................... 5. jxlli "* B 0366....... 3, ixlG * B 03 6 7

0,0x10'’ B ' QiiS: ,x x ir ” B QiZS

.................3,3x30'’ m 5100

...................... .3,x»30'’ B ClOl

.............. 3.8x30'’ B Cl Oil0.P,X'30'’ B 0153

_______ l . ix lS '” B 5364O.SXII:'* B 53662. axlfi"’ B 51863.1X30'’ B 5157

..................... 5. Sxii3’’ l'« 0156

............ ........ 1,1x113'’ I*i4 0150

Figure 3<14 Feedwater system <state tree.

3.4.4 Quantification of the Primary Loop ECCS System State Tree

3.4.4.1 High-Pressure Injection System Activates on Demand

STATE 0: P = 1.0 - P(State

STATE 1: NHREG/CR-2497 provides a probability for HPI system failures_3

on demand of 1.3 z 10 /demand. HPI unavailabilities at the

pump/train level observed at Oconee between April 1978 and

September 1981 (41 plant-montbs) include:

Oconee Unavailabilitv Date

3 train B 11/78

3 train A 4/78

2 pump A 2/81

2 pump B 1/81

2 pump B 11/80

2 pump B 7/80

2 pump B 7/80

Assuming these seven failures to be unconnected (this is.

in actuality. probably not so with the four Oconee 2 pump

B failures) on both a train and pump basis results in the

following unavailability estimates:

7/(41 mo z 2 trains/plant z 3 plants) == 0.028

and

7/(41 mo z 3 pumps/plant z 3 plants) = 0.019

3 . 5 1

With only one train or pump required for success, one can

derive system failure probabilities of 0.028 (first train)

X 0.1 (second train x failure given failure of the first

train) = 2.8 x 10 /demand

and

0.019 (first pump) x 0.1 (second pump x failure given

failure of the first) x 0.3 (third pump x failure given—4

failure of the first and second) = 6 x 10 /demand. These

values are consistent vith the NUREG/CR-2497 value of 1.3 x-310 /demand, which was used in this analysis.

3.4.4.2 Core Flood Tanks Discharge upon Demand

STATE 0: P = 1.0 - P(State ^)

STATE 1: Since the CFT system is a passive one, the failure

probability is assumed to be dominated by the failure of

either check valve connecting the CFTs to the downcomer to

open on demand. This is assumed to be 4.0 x 10 ^ for at

least one check valve in each line.

3.4.4.3 Low-Pressure Safety Injection into Downcomer Initiated

STATE 0: P = 1.0 - P(State ^)

STATE 1: A value of 4.5 x 10 ^ for the unavailability of the LPI

system (given CFT successful operation) is assumed.

3.52

3.4.4.4 Modifications of Primary Loop ECCS Probabilities Due to

Conditioning Events and/or Previous Failures

The only system assumed to be affected by either conditioning events or

previous failures is the LPI system whose operation is assumed conditional

on the success or failure of the core flood tanks. This interdependence

arises because both systems flow through a common check valve. Thus, for

those branches involving failure of the CFT to inject given a demand, the

corresponding LPI probabilities are assumed to be:

STATE 0: 0.75

STATE 1: 0.25

Using these assumptions, the overall primary loop ECCS system state tree

given by Figure 3.15 was constructed.

3.4.5 Quantification of the Primary Loop Pressure Control System State

Tree

3.4.5.1 PORV Opens on Demand

STATE 0: 1 - P(State ,) ~ 1.01 ~

STATE 1: A value of 1.0 z 10 ^ (WASH-1400) was assumed.

3.4.5.2 SRV Reseats upon Demand

STATE 0: 1 - P(State

STATE 1: The probability of a single SRV failing to reseat is assumed

3.53

MINIMUn HPI CFT LPI FREOUENCT SEQUENCERCS PRESS INITinTED DISCHflRQE INITIflTED (/RY) NUMBER

I.OhIo”10.0m10‘‘

CCCOlECC02EG003

3.9x10"' EC0041.3h10"'lO.Oxlo"'

ECC05ECC06

3.0x10'' EC007lO.Oxlo'® E0C081.3x10"' ECC093.9x10'® ECO 101.3x10'® ECCll10.0x10' ECC 124.5x10' ECC 133.0x10'® ECC 14lO.Oxlo'® ECC 151.3x10'® ECC 165.8x10'' ECC 173.9x10'® ECC 181.3x10'® ECC 19

Figure 3.15 Primary loop ECCS system state tree; initiator;unspecified.

—2to be 1.0 X 10 /demand. Since tbe Oconee 1 plant has two-2SRVs, a probability of 2.9 x 10 is used.

3.4.5.3 PORV Reseats upon Demand

STATE 0: 1 - P(State = .973

STATE 1: NIJREG-0560 reports four failures of the PORV to close when

expected, once it had opened, in approximately 150 demands._2This results in a failure probability of 4/15 = 2.7 x 10

Using these assumptions, the overall primary pressure control system state

tree given by Figure 3.16 was constructed.

3.55

mXIMUMR c s p r e :s s

PCRV OPENS BLOK VRLVE OPEN

SRVRESEATS

PORVRESEPTS

FREQUENCYt/R Y )

SEQUENCENUMBER

Ln0\

PPCOl8.8xl0"‘ PPC022.4h10'' PPC039.4k10‘" PPC046.0x10"" PPCG52.8x10"* PPC061.8x10'' PPC078.3x10'* PPC082.3x10'" PPC095.3x10'" PPG 101.5x10'' PPCll9.4x10'" PPG 126.0x10'' PPC132.8x10"* PPG 141.8x10'' PPC15

Figure 3.16 Primary pressure control system state tree; initiator:unspecified.

3.5 TRANSIENT CATEGORIZATION

To reduce tEe potentially large nnmber of end-states (6,9335,760) that

result from the combination of the four system state trees (SPG, FWS,

ECC, and PPG), it is useful to group transients with similar thermal-

hydraulic behavior into categories. The individual end state frequencies

can be summed to give a category frequency and a representative transient

selected to estimate the conditional probability of vessel failure, given

the occurrence of the transient. The categories were chosen largely on

the basis of the operator action involved, but all were not monotonically

increasing in PTS severity. The following categories have therefore been

defined:

3.5.1 Secondary Pressure-Gontrol System (SPG)

GATEGORY 0: No significant thermal-hydraulic effect. This category

accounts for those transients in which either no

malfunctions take place or in which a malfunction does

occur but does not affect the course of the transient.

An example of the latter case is that of a 16V failure

to open on demand, but where the SSRVs operate to limit

the secondary side pressure.

CATEGORY 1: This category is appropriate for those transients

involving a nonisolable break in a single steam line.

Typically, breaks in the steam line upstream of the TSVs,

or stuck-open SSRVs, fall in this category.

3.57

CATEGORY 2: Tliis category involves those transients in which an

isolable break is present in a single steam line. This

category is typified by a stnck open TBV (isolable by the

turbine block valves) or a steam line break downstream of

the TSVs.

CATEGORY 3: This category involves those transients in which both

steam lines are subject to depressurization due to a

secondary pressure-control malfunction and neither steam

line can be isolated from the break(s). An example of

this category is a transient involving a stuck open SSRV

on each steam line (perhaps because of a common-cause

effect).

CATEGORY 4: This category accounts for those transients in which both

steam lines are involved but in which one can be isolated

from the break(s). It thus combines malfunctions of

Categories 1 and 2.

CATEGORY 5: This category accounts for those transients in which both

steam lines are involved and in which both steam lines

can be isolated from the break(s). An example of this

category is a transient involving a stuck-open TBV on

each steam line.

CATEGORY 6: This category is a catchall to account for those

transients (end-states) that cannot be characterized

3.58

by Categories 0 tbrongb 5 and that mnst be examined

individually to determine the thermal-hydraulic response.

3.5.2 Feedwater System (FWS)

CATEGORY 0: No significant thermal-hydraulic effect. An example of

this category would be a transient in which the HFW

system is lost on an attempted runback together with the

operation of the EFW system as designed.

CATEGORY 1: This category accounts for those transients that involve

an unsustained NFW overfeed. That is> an MFW overfeed

is terminated by the high SG level trip system.

CATEGORY 2: This category accounts for those transients that involve

a sustained HFW overfeed, typically because of a failure

of the high-level trip system.

CATEGORY 3: This category accounts for those transients that involve

an overfeed by the EFW system. Thus, it also includes

those transients in which a MFW overfeed has taken place

(either sustained or unsustained) together with an EFW

overfeed.

CATEGORY 4: This category accounts for those transients in which all

feedwater (HFW and EFW) is lost to the steam generators.

An example transient in this category is one in which the

HFW system is lost on an attempted runback and the EFW

system fails to initiate.

3.59

3.5.3 Emergency Core Cooling System (ECCS)

CATEGORY 0: This category accounts for the transients in which no

ECCS failures occur. An example of this category is one

in which no demand for the ECCS function is made (i.e.,

primary system pressure remains above the HPI set point

of 1500 psi).

CATEGORY 1: This category is comprised of those transients in

which the HPI system fails to initiate upon demand.

Although HPI failure effectively prohibits system repres-

surization, the HPI failure can cause a demand for the

CFT and LPI systems (which inject directly into the

downcomer), which is a potential PTS concern. Moreover,

the possibility of operator action to restore the HPI

function must be addressed.

CATEGORY 2: This category accounts for multiple failures within the

ECC system, such as HPI and CFT failures.

3.5.4 Primary Pressure (k>ntrol System (PPC)

CATEGORY 0: This category is characterized by no failures within

the primary pressure control system (i.e., the PORV and

SRYs).

CATEGORY 1: This category involves those breaks in the primary

coolant system which can be isolated. An example of this

3.60

is a stnck-open PORV that can be isolated by the block

valve dovnstream.

CATEGORY 2: This category involves those primary system break that

are not isolable, such as a stnck-open SRV or a small

break in one of the coolant legs.

As a notational convenience, transients are identified by four category

numbers, ordered as follows: SPG, FWS, ECC, and PPC. Thus, a transient

designated as (1,3,0,1) indicates SPC Category 1, FWS Category 3, ECC

Category 0, and PPC Category 1, and can be described as a nonisolable break

in one steam line coupled with an EFW overfeed and a failure of the PORV.

3.6 Initiator-Specific System State Tree Construction

To employ the methodology outlined in the previous sections, a initiator-

specific system state tree must be constructed for each initiator of

interest. This construction consists of specifying conditioning event

states appropriate for the initiator for each of the four system state

trees, combining the four system state trees into an overall system state

tree that describes the asymptotic end-states that remain possible, pruning

those end states whose frequency is below the cutoff value (taken as

l.Oe-06/RY in this study) from the overall tree, and finally evaluating

the effect of operator actions by which the frequency (and in some cases,

the possibility) of various end states can be altered. The initiators

considered in this study are listed in Table 3.5. For each initiator

listed, an overall system state tree was constructed and evaluated, and

this procedure will be discussed in the following sections.

3 . 6 1

Table 3.5. Initiating events and frequencies utilized in PTS study

Initiating Event Assumed Frequency (/HI)

Reactor/Turbine Trip 6.0E+00Excessive MFW l.OE-01LSLB l.OE-03SSLB l.OE-02Loss of MFW 5.0E-01SB LOCAl l.OE-01SB L0CA2 l.OE-02Inadvertent SI l.OE-02S6TR l.OE-02

3.62

3.6.1 Re act or/Turbine Trip

3.6.1.1 Initial Coxiditions and Conditioning Event Assumptions

The initial conditions for this initiator assianed that reactor power is

greater than 45% and that the decay heat capability of the core was

approximately the ANS standard. Based on the specified initial conditions,

the following conditioning event assumptions were made:

1. Following the trip, the steam line pressure in both steam

lines will be sufficient to challenge both the turbine

bypass system and the secondary-side relief valves (at least

momentarily). Thus, the high SL pressure branches for both

steam lines on the SPC system state tree are activated.

2. The HFW system is operating with both HFW pumps on-line,

and in the absence of any secondary side pressure control

difficulty, the HFW line pressure will remain above the EFW

initiation set point. If any secondary pressure-control

valve fails to reseat (either a TBV or a SSRV), it is

assumed that the MFW line pressure will decrease below

the EFW set point (725 psi). Further, should a secondary

side depressurization take place, it is assumed that such a

depressurization will not be rapid enough to induce a false

high-level signal from the instruments. Therefore, it is

assumed that the SG level signals are nominally correct for

all cases.

3.63

3. With regard to the ECC system, it is assumed that, if

no secondary~side depressurization or overfeed occurs, no

demand for an ECCS response vill be made. If either a

depressurization or an overfeed takes place, it is further

assumed that only the HPI system will be demanded.

4. It is assumed that the PORV block valve is closed 50% of the

time. This assumption is conservative in that it forces the

safety valves to open more frequently. The safety valves

cannot have block valves, and thus a failed-open safety

valve is a nonisolable break.

Since this is the first initiator to be discussed, it is useful to observe

the effect of these conditioning event assumptions on the four system

state trees. The four trees are given by Figures 3.17 through 3.20. As

indicated in assumption 2 above, two FW system state trees result from the

depressurization/no-depressurization cases.

3.6.1.2 Reactor/Turbine Trip System State Tree

Combining the four system state trees given by Figures 3.17 through 3.20

results in an overall reactor trip system state tree comprised of 448 end-

states with frequencies greater than l.OE-06. Additionally, the end states

eliminated in the pruning process represent an additional frequency of

1.9E-04. As an alternate perspective, the surviving end-states have been

grouped according to the system (or systems) that malfunctioned during the

transient. These results are presented in Table 3.6. As expected, the case

of no malfunctions clearly dominates in terms of frequency of occurrence.

3.64

nira'WKI KWH LBC cuac n trw"'I ngm jrt? ■ a r s R — “ T3«T--- IMIJL8 “ STTB?— i m a j —ftCSCRTKSEX oasc 1 piEsajRC nouuinr TBBBS"i/»n

8. Sal o'* SPCOOOl6.5*10'' SPC00027.7*10'* SPC00035.9*10'* SPCOOOl7.7*10'* SPC0Q055.9*10'* SPC00060.07.9*10"* 5PC00126.5*10" SPC0013l.'talO" SPCOOH5.9*10" 5PC00151.5*10" SPC00165.9*10" SPC00171.3*10" SPC0Q180.06.8*10" SPC00217.7*10" SPC0Q255.9*10" SPC00268.5*10" SPC00276.5*10" 5PC00289.2*10"0.07.9*1 O'* SPC00365.9*10" SPC00371.3»10" SPC00386.5*10" SPC0039i.-t*io" SPCOO-tO8.0*10"0.06.8»10"7.7*10" spcoo-tg5.9*10" SPCOQSO8.5*10" 5PC00S36.5*10'' SPCOQSO9.2*10"0.07.9*10"5.9*1Q" SPC00611.3*10" SPC00625.5*10" SPC0Q65l.t*10" SPC0Q668.0»10"0.06.8*10"0.07.9*10" SPCG1336.1*10" SPC01347.1»10" 5PC01355.5*10"7.7*10"0.09.5»10" spcom

Figure 3.17 Secondary pressure control system state tree; initiator: unspecified.

3.65

HFHS HFW PUMPS EFHPS EFW FLOW FREQUENCY SEQUENCERUNBRCK HLSQ TRIP STRRX CNTL/LEVEL t/RY) NUMBER

ONCT

HFH SYS. RVfllLflBLE?

MFH ON, HI ,NWlNfi MFH LINE PRESSURE?

SG LEVEL S19NHLS

_ 9.4h 10‘V w 0024_ 2.8xlO'Vw 0025_ 4.7xlO'VW 0026_ 2.8xlO’Vw 0027_ 1.6> 10‘Vw 0028. 3.9x10 rw 0029

1.2xlO‘Vw 00302.8xl0'i^W 00314.7’kIO'Vn 00322.8k 10>W 0033l.BxlO’Vw00343.9x10* ^ 00352.8xlO'^rW 00362.8xlO''rW 00374.7xlG'^W 0038

. 2.8xlo1^W 0039

. i.exio’Vw 0040

. B.QxlO'Vw 0041. 0*0. 0.0

0.0

Figure 3.18a Feedwater system state tree; initiator: unspecified.

MFH ON.LOH .NOHlNflL

MFH SYS. HFH LINE S0 LEVEL HFHS MFH PUMPS EFHPS EFH FLOH FREQUENCIfiVfllLflBLE? PRESSURE? SI6NRLS RUNBfICK HLS8 TRIP SIRRT CNTL/LEVEL (/Rt) SEQUENCENUMBER

O'

9.3h]0''

e.SHio"*5.3»<1Q^1.3«10'^2.8x10'*'4.7x10'®2.8x10'®i.exio"®3.9x10'®1.axio"®2. Ix'lO'® i.axio"®6.9x10'®1.7x10"®2.8x10^'4.7x10'*2.8x10"®1.6x10'®3.9x10'®2.8x10"®5 .0 x 1 0 '”2.0x10"®a.exio"®4.7x10"®2.8x10'®i.exio"*3.9x10"*0.00.00 . 0

FW 0095FW 0096FW 0097FW 0098FW 0099FW 0100FW 0101FW 0102FW 0103FW 0104FW 0105FW 0106

FW 0108FW 0109FW 0110FW 0111FW 0112FW 0113FW 0114FW 0115

FW 0120FW 0121FW 0122FW 0123FW 0124

Figure 3.18b Feedwater system state tree; initiator: unspecified.

LOW RCS MINIMUM HPI CPI LPI FREDUENCy SEQUENCEPRESSURE RCS PRESS INITIATED DISCHARGE INITIATED (/RY) NUMBER

ON00

10.0><i0"‘ ECC0002

ECC0003

3.9k10'® ECC0004

1.3K10 ECC0005

0.0

Figure 3.19 Primary loop ECCS system state tree; initiator: low RCS pressure.

PORVDEMRND

mXIMUM RCS PRESS

PORV OPENS BLCK VRLVE OPEN

SRVRESERTS

PORVRESERTS

FREQUENCYl/R Y )

SEQUENCENUMBER

VD

4.9x10 PPCGGG2

,-21.3x10 PPCGGG3

4.7x10 PPCGGG4

3.0x10"" PPC0005

2.8x10"* PPC0006

1.8x10"' PPC0007

0.0

Figure 3.20 Primary pressure control system state tree.

Table 3.6 Reactor trip transient snmmary

System Number of Transients Frequency (/RY)

None 12 5.0+0SPC 79 7.8-1FWC 43 1.6-1SPC + FWS 114 3.0-2SPC + ECC 13 1.0-3SPC + PPC 73 7.0-2FWS + ECC — —FWS + PPC 27 2.7-4SPC + FWS + ECC 9 3.5-5SPC + FWS + PPC 70 2.8-3SPC + ECC + PPC 8 8.6-5

448 6.0+0

Residual 1.9-4

3.70

In terms of nnmber of end-states, the transients involving malfunctions

of both the secondary pressnre control and feedwater systems are the most

numerons. Further, the transients which involve only a SPC malfunction are

the most likely of those transients that involve malfunctions. A complete

list of all transients for this initiator is given in Appendix A, Table

A.l together with the classification of each transient into an appropriate

category.

3.6.2 Excessive EFW: Initial Conditions and Conditioning Event Assumptions

The initial conditions assumed for this initiator are reactor power greater

than 45% and the ANS standard decay heat. Based on the initial conditions,

the following conditioning event assumptions were made:

1. Eventual reactor trip on either low RCS pressure or

unbalanced primary thermal-hydraulic parameters.

2. Following the reactor trip, assumption that the pressure in

both steam lines is sufficient to challenge the secondary

side relief valves.

3. MFW system operating with both MFW pumps on line. In the

absence of a secondary side depressurization due to a stuck-

open valve, it is assumed that the MFW line pressure remains

above the EFW initiation setpoint.

4. The primary-side pressure, assumed to decrease (due to the

MFW overfeed) to below the HPI set point, but to remain

above the CFT set point.

3 . 7 1

s . Assumption that the PORV block valve is closed 50% of the

time.

3.6.3 Large Steam Line Break (LSLB): Initial Conditions and Conditioning

Event Assnmptions

The assumed initial conditions are reactor power greater than 45% power

and ANS standard decay heat. The size of the large steam line break is

assumed to he sufficient to depressurize the steam generator to below the

EFW initiation point. Based on these initial conditions, the following

conditioning events were selected:

1. Low SL pressure in the broken steam line to the extent that

neither the relief valves nor the IBVs are challenged. It

is assumed that the pressure in the unaffected steam line

following the reactor trip is sufficient to challenge both

the secondary relief valves and the turbine bypass valves.

2. NFW system is on, but MFW line pressnre decreases to below

the ERW initiation point.

3. Minimum primary system pressure between 610 and 1500 psi.

4. PORV block valve closed 50% of the time.

3.72

3.6.4 Small Steam Line Break

Initial Conditions and Conditioning Event Assnmptions

The initial conditions assumed are reactor power greater than 45% and

ANS standard decay heat. The size of the steam line break is assnmed

to be insufficient to depressurize the steam generator to the EFW

initiation point. Given these assumptions, the following conditioning

event assumptions were made:

1. Steam line pressure in the affected steam line is low enough

not to challenge either SSRVs or IBVs. Pressure in the

unaffected steam line is sufficient (following reactor trip)

to challenge both the SSRVs and the IBVs.

2. MFW system is initially on line; the depressurization caused

by the steam line break is not sufficient to initiate the

EFW.

3. Minimum RCS pressure reached is between 610 and 1500 psi

(only HPI system demanded).

4. Maximum RCS pressure is sufficient to challenge both the

PORV and the SRVs.

5. PORV block valve is closed 50% of the time.

3.73

3.6.5 Loss of MFW (LOHFW): Initial Conditions and Conditioning Event

Assnmptions

The initial conditions for the LOMFW initiator are reactor power greater

than 45% and the ANS standard decay heat. A trip of the NFW pnmps at the

start of the transient is assnmed. Based on the initial conditions, the

following conditioning event assnmptions were made:

1. Steam line pressure in both steam lines (following reactor

trip) sufficient to challenge both the relief valves and

turbine bypass system.

2. MFW system is unavailable.

3. Primary-side pressure is assumed to be sufficient (given a

failure of the EFW system to initiate) to challenge both the

PORV and the code safety valves.

4. No ECCS demand is assumed if a secondary-side overfeed does

not occur. Given an overfeed, it is assumed that only the

HPI system is demanded.

5. The PORV block valve is closed 50% of the time.

3.6.6 Small Break LOCA 1: Initial Conditions and Conditioning Event

Assumptions

The initial conditions assumed for this initiator are reactor power greater

than 45% and ANS standard decay heat. The size of the break is assumed to

be large enough to depressurize the primary system below the HPI set-point.

3.74

Additionally, it is assumed the break is small enough that the HPI system

is capable of repressnrizing to the PORV/SRV set-points. Based on these

specifications, the following conditioning event assnmptions were made:

1. Reactor trip on low RCS pressnre.

2. High steam line pressnre in both steam lines following the

reactor trip. Both SSRVs and TBVs are challenged.

3. MFW system operating. MFW line pressnre greater than 725 psi

for cases with no secondary pressure control malfunctions;

less than 725 psi for any secondary pressnre control

malfunction (TBVs or SSRVs).

4. Only the HPI system will be demanded.

5. PORV block valve closed 50% of the time.

3.6.7 Small Break LOCA 2: Initial Conditions and Conditioning Event

Assnmptions

The initial conditions assnmed for this initiator are the same as for the

smal 1-break LOCA 1 case. However, the size of this break is asstuaed to

be large enough to prevent the HPI system from repressnrizing the primary

to either the PORV or SRV set points. The following conditioning event

assnmptions were made:

1. Reactor trip on low RCS pressnre.

2. High steam line pressnre in both steam lines following the

reactor trip challenging both the TBVs and the SSRVs.

3.75

3. NFW system operating. NFW line pressnre remains greater

than 725 psi if no secondary depressurization occnrs.

4. Only the HPI system is demanded.

3.6.8 Inadvertent Safety Injection (SI): Initial Conditions and

Conditioning Event Assumptions

The initial conditions assumed are reactor power greater than 45% and ANS

standard decay heat. The following conditioning event assumptions were

made:

1. Reactor trip on high RCS pressure.

2. Nazimum steam line pressure in both steam lines. Both TBVs

and SSRVs are challenged.

3. NFW system operating. NFW line pressure greater than 725

psi for no secondary-side depressurization.

4. Nazimum primary-system pressure— both PORV and SRVs chal­

lenged.

5. PORV block valve closed 50% of the time.

3.6.9 Categorization of Initiator-Specific Asymptotic Transients

Table A.l (Appendiz A) summarizes the relevant information for the 1013

initiator-specific asymptotic end-states that survive the pruning process.

In particular, each transient is described by a sequence number (which

is the position of the particular transient in the set of 6,935,760

3.76

possible transients) and four system state branch descriptors that delineate

the particular system state tree end-states reached for the transient.

Additionally, the estimated asymptotic event frequencies are tabulated.

Finally, the system state categories appropriate for each transient (based

on the particular system state end-states) are listed. Examination of

all the transients vill reveal that certain category groupings occur more

than once. Hence, in order to reduce the number of transients to a more

manageable level, transients with identical categorizations were combined.

The transients thus obtained are given in Table A.2.

3.7 Effect of Operator Actions

As discussed previously, it is necessary to construct an operator action

tree detailing those operator actions that significantly affect the thermal-

hydraulic behavior of the system for each unique end-state. Hovever, in

keeping with the categorization of the end-states, it is assumed that an

operator action tree constructed for a representative transient in the

category can be applied to all transients in the category.

As noted in the discussion of conditioning events, it is assumed that any

secondary-side depressurization or overfeed vill lead to a demand for the

HPI system because of lov primary system pressure. Thus, for SPC Category

1 transients, the first relevant operator action is the trip of the reactor

coolant pumps on the valid ECCS demand signal. This action is particularly

important on B6W plants because the trip of the RC pumps permits the vent

valves to function in a manner to mitigate the cooldovn of the vessel.

On diagnosing the problem as a secondary— side rupture or excessive steam

demand, the next relevant step is the isolation of both S6s as called for

3.77

in the procedure. Once the broken secondary loop has been identified, the

next action is the restoration of feedwater to the unaffected loop (and

hence the restoration of the secondary heat sink). The remaining relevant

operator actions consist of throttling the HPI system and the restart of

one RC pump per loop when a SO^’f snbcooling margin has been attained.

Since a detailed task analysis of the relevant procedure was not performed,

generic human error probabilities (HEPs) were used to estimate the

mitigative potential of the generator. For most actions a HEP value of 1.0-2X 10 was employed for the first error in a sequence. The HEP for each

succeeding error was obtained by doubling the previous value. For certain

specific actions for which extensive training had been accomplished (such

as the trip of the RC pumps on a valid ECC signal), a HEP value of 5.0-3X 10 was employed. It should be noted that each operator action requires

that a time interval be associated with it. The generic probabilities

discussed above are based on operator action within a 10-min time frame

except for the RC pump trip in which it is assumed that a 30-s time frame

was sufficient for operator action, if it was to be taken at all.

The operator action tree, constructed using the above assTimptions, is

depicted by Figure 3.21 and is strictly appropriate to only Category

(1,0,0,0) transients. However, it is observed that PSC02 transients differ

only in the fact that the break can be isolated (e.g., a stuck-open TBV

versus a SSRV). It should be noted, however, that a successful isolation

of SGs will result in similar conditions in both steam lines (due to the

closure of the turbine bypass valves), which will make the diagnosis of

3.78

SPCO l RC P U IF S S O 'S IS O L . SECOND HS HP IN JE C T RC PUMPS FREQUENCY SEQUENCENFF T R IP B r OPER RESTORED THROTTLED RESTARTED (/R Y ) NUMBER

•vj

9.2><10'‘ on 00012.8x10'" on 00022.8xl0‘" on 00031.8xlG‘' on 00048.7x10'' on 0005S.BxlO"* on 00065.2x10“ on 00077.1x10“' on 00088.8xl0‘' on 00095.6x10“* on 00105.3x10'* on 00117.2x10'' on 00124.5x10'" on 00132.9x10'* on 00148.6x10'" on 00151.2x10'" on 00168.8x10'" on 00171.2x10'" on 0018

Figure 3.21 SPCOl operator action tree; initiator: SPCOl.

COo

SPC03 RC PUMPS SG*S ISOL. FEED/BLEED FREQUENCY SEQUENCENFF TRIP BY OPER CONTROLLED (/RY) NUMBER

9.8k 10"' on 00019.9h 10'' on 00029.8k 10‘" on 00032.0k 10' on 00044. 8 10'' on 00059.8x10“' on 00069.6x10'® on 00074.0x10“' on 0008

Figure 3.22 SPC03 operator action tree; initiator: SPC03.

the affected steam line more difficnlt. Attempted restoration of the

secondary heat sink, however, will indicate the affected steam line.

For an SPC Category 3 transient, isolation of the steam generators will not

isolate the break, resulting in a depressnrization of both S6s. Because

neither 6S can be restored as a heat sink, it is assumed the reactor

operators will provide cooling to the core via the HPI system (i.e., a

feed/bleed mode). The operator action tree for this case is given by

Figure 3.22.

For SPC Category 4, one steam generator will appear to be unaffected.

However, attempted restoration will indicate that one or more TBVs are

stuck open. It is assumed that the steam generator can be restored as

a viable secondary heat sink by limiting the steam flow through the turbine

bypass block valves. Thus, the appropriate operator action tree for the

case is given by Figure 3.22. In an analogous fashion, this same operator

action tree can also be used for SPC Category 5 transients.

As noted above, SPC Category 6 transients principally account for failures

of the TSVs to close on both lines. If the turbine governing valves close,

these transients can be categorized as SPC Category 0. However, a failure

to trip the turbine, given a reactor trip, will result in an excessive

steam demand relative to the power output of the reactor. Assuming—4a turbine trip failure probability of 2 z 10 /demand yields a revised

-3frequency for SPC Category 6 transients of 1.2 z 10 . In this case,

manual tripping of the turbine, or failing that, manual closure of the

turbine stop valves and/or the turbine governing valves will effectively

isolate the break. It is assumed that, should the manual isolation of the

3 . 8 1

turbine not be accomplished, the transient will be treated as a "double"

steam line rupture (SPC Category 3) with similar operator actions. The

operator action tree for this case is given by Figure 3.23.

For those actions involving only malfunctions of the feedwater system

[Category (0,N,0,0)], a different set of operator action trees is

appropriate. The first nontrivial Category (0,1,0,0) involves unsustained

MFW overfeeds to one or both of the S6s. It is assumed that the time frame

of this overfeed is short enough to preclude any operator action before

the high-level 86 trip system terminates the transient itself.

For FWS Categories 2 and 3, which involve sustained overfeeds by the MFW

and EPV systems respectively, the operator action tree given by Figure

3.24 was constructed. An implicit assumption inherent in his tree is

the initiation of he HPI system on low RCS pressure, thereby requiring a

trip of the RC pumps. The FWS Category, however, is characterized by a

very different thermal-hydraulic behavior. Since this category represents

a loss of both the MW and EFW systems on reactor trips, an automatic

HPI initiation on low RCS pressure is not expected, and the RC pump trip

will not be procedurally required. Additionally, one reason for the non­

initiation of the EFW system is that the system was originally in a manual

mode of operation, requiring only a switch bach to automatic mode to effect

EFW supply. The HEP assigned to this branch was 0.01. Alternatively

the EFW system may be unavailable for other reasons. However, because of

the interconnections possible between the EFW system of the three Oconee

units, a 0.98 probability of success of EFW restoration was assumed for

this branch. Also, a potential operator error of commission, restoration

3.82

SPC06NTF TURBINE RC PUMPS SB'S ISOL. SECOND HS HP INJECT RC PUMPS FREQUENCYI30LBIED TRIP BY OPER RESTORED THROTTLED RE5TRRTE0 C/RY)SEQUENCENUMBER

00

9 . 3 h 10’’ 08 00012 .9 x 1 0 ^ OR 00022 . 6 h 10'* 08 00031 .8 h 1D^ on 00044.-1X10'' OR 00052.8x10'^ OR 00062 .6 x 1 0 ' ' OR 00073 .6 x 1 0 ^ on 00089.2x10 '" on 00092 .0 x 1 0 ' ' OR 00102 .8 x 1 0 ' ' OR 00111 .8 x 1 0 ’’ OR 0012S./xlO"® on 00135.6x10'® on 00145 .2 x 1 0 ’* OR 00157. I x io ' ' OR 00168 .0x10 '* OR 00175.6x10'® on 00185.3x10'® on 00197 .2 x 1 0 ' ' on 00204 .5x10 '* OR 00212 .9 x 1 0 '“ OR 00228 .6 x 1 0 ' ' on 00231 .2x10 '' on 00248 .8 x 1 0 ' ' OR 00251 .2 x 1 0 ’' OR 0026

Figure 3.23 SPC06 operator action tree; initiator: SPC06.

00

FWS04NFF

EFW SYSTEM IN MRNURL

EFWRESTORED

MFWRESTORED

FREQUENCYI/RY)

SEQUENCENUMBER

2.9k 10‘‘ on OGGI

2.9k 10‘" on GGG27.0m 10"‘ on GGG37. iHlO'" on GGG4

3.5><10''’ on GGG57. iHlO'" GR GGG6

3.6k 10'' GR GGG7

Figure 3.24 FWS04 operator action tree; initiator: FWS04,

of EFW in an uncontrolled manner (ERW overfeed), was also included with

a HEP of 0.01. Should EFW restoration not be possible, a probability of

0.5 of MFW restoration in an uncontrolled manner was employed.

For most of the transients involving both SPC and FWS malfunctions,

isolation of the steam generators mitigates the FWS malfunction. Therefore,

the appropriate operator action trees for categories designated (N,N,0,0)

are the same trees as discussed above for Categories (N,0,0,0). It should

be emphasized, however, that a SPC malfunction coupled with an overfeed

results in more severe thermal-hydraulic behavior even though the operator

actions necessary to mitigate the transient remain the same. For those

combined transients involving FWS Category 4 (loss of all FW), however,

a modified form of the SPC operator action trees is employed. The

modification consists of changing the probability of heat sink restoration

to agree with that indicated by Figure 3.24 to account for the possibility

of uncontrolled EFW or MFW restoration (l.OE-02 and 7.1E-05, respectively).

For those transients involving a failure of the HPI to initiate, a

conservative approximation is made. Because the HPI system will exacerbate

a PTS transient (higher pressure and lower temperature in the downcomer),

those transients that involve HPI failure are included in the category

representing HPI success.

For those transients in which the pressure in the RC system reaches

the PORV/SRV set points, the operator actions necessary to deal with a

potential LOCA situation must be addressed. Two types of potential LOCAs

are represented by the categorization process— LOCAs isolable via the PORV

block valve and non-isolable LOCAs involving the SRVs. It should be noted

3.85

that the LOCA situation may not be initially apparent in many of the tran­

sients because the effects may be masked by the overcooling of the primary

system. Hence in this study, the conservative assumption was made that for

those transients involving secondary-side depressnrization or excessive

feedwater. the LOCA situation will only be dealt with following correction

of the secondary side malfunction. For PORV LOCAs. the system can be sta­

bilized by closing the PORV block valve and throttling back the HPI, given

that the secondary heat sink has been restored. Thus, an additional opera­

tor action, closing the PORV block valve, should be incorporated into the

operator action tree. For the nonisolable LOCA. the ECCS flow rate will

match the break flow at a pressure lower than operating pressure. In both

cases, however, the appropriate operator action depends on the availability

of the secondary heat sink. If it is available. it is assumed that no

operator action is taken to alter the feed/bleed mode in the RCS. If the

SGs are not (or cannot be) restored, an operator action to depressurize the

primary system to utilize the LPI system, is appropriate and is included on

those branches for which secondary side cooling is not restored. Figure

3.25 depicts the operator action tree for Category (1.0.0.1) as an example.

The above discussion is intended to serve as background for the discussion

of initiator-specific transients. In many cases, the operator action

trees postulated are directly applicable to the transients involved. In

certain cases, however, the initiators themselves require modification

of the generic operator action trees postulated based on the transient

categorization. The necessary modifications will be indicated in the

discussion of each specific initiator where appropriate.

3.86

00

SPCOlLOCfl

RC PUMPS TRIP

SG'S ISOL. BY OPER

SECOND HS RESTORED

RCSDEPRESS

FREQUENCY1/RY)

SEQUENCENUMBER

9.8k 10'* on 00019.3h 10'' on 0002

on 00039.4h 10'' on 00046.0x10"* on 00054.8x10' on 00068 . 6 x 1 0 ' ' on 0007

on 00088 . 8 x 1 0 ' ' on 00091 . 2 x 1 0 " ' on 0010

Figure 3.25 SPCOl/LOCA operator action tree; initiator: SPCOl/LOCA.

4.0 THERMAL-HTDRAULIC EVALUATION

L. B. LaMonica, Science Applications, Inc.

4.1

The role of thermal-hydraulic analysis in the probabilistic evaluation of

PTS risks is to couple event tree analysis to the fracture nechanics (FN)

analysis. Each end-state on an event tree defines a series of actions

and/or failures that detemines the response of the plant to the initiating

event. The thermal-hydraulic response— measured as downcomer pressure,

liquid temperature, and heat transfer coefficient— becomes the boundary

condition used in the fracture mechanics calculation of crack propagation

probability.

A thoroughly rigorous evaluation of PTS risk would require precise

calculation of downcomer pressure, temperature, and heat transfer

coefficient over the entire downcomer region for every event tree end-

state. Since there are over 9.6 million end-states on the Oconee-1

event trees and detailed thermal-hydraulic simulation costs are great, a

completely rigorous approach is not practical.

A first simplification of the scope of the analysis may be achieved by the

use of a lower limit (10 V yt) on event frequency to screen out a very

large number of events which individually would not measurably contribute

to overall risk. This screening process is described in Chapter 3.0.

The remaining sequences are still too numerous for individual detailed

evaluation. Furthermore, the development of pressure, temperature, and

heat transfer conditions over the entier downcomer region (i.e., azimuthal

4.1

and axial variations in the bonndary conditions) vonld necessitate the nse

of TRAC or a revised RELAP5 model including multiple downcomer regions.

Therefore, a combination of detailed calculations and engineering estimates

was employed to define "single point" pressure, temperature, and heat

transfer coefficient boundary conditions for all of the sequences. These

single point profiles assume a uniform temperature, pressure, and heat

transfer coefficient throughout the downcomer region. Where a range of

temperatures could be predicated by TRAC or by extrapolation, the downcomer

sector with the lowest temperature profile was used for the FM analysis.

The detailed calculations were performed by Fletcher, et al., at the4 1Idaho National Engineering Laboratory (INEL) using the RELAPS code ' and

by Ireland, et al., at Los Alamos National Laboratory (LAND using the 4 2TRAC-PPl code. ‘ The models developed at INEL and LANL included the

primary and secondary portions of the nuclear steam supply system, main and

emergency feedwater trains, and certain control functions of the ICS. At

the time of their creation, these Oconee-1 plant models were the largest

and most complex models ever applied to the RELAP5 and TRAC-PFl codes. The

characteristics of these models are summarized in Section 4.2.

Oak Ridge National Laboratory identified 14 transient sequences for detailed

evaluation. Tables 4.1 and 4.2 contain a brief description of each

sequence simulated using RELAP5 and TRAC respectively. For purposes of

comparison, the Oconee-3 turbine trip (revised), aiain steamline break, and

pressurizer surge line small-break events were calculated using both RELAP5

and TRAC. More detailed descriptions of the sequences are provided in

Section 4.3. The transient sequences were selected to include 1) major

4.2

Table 4.1 INEL Oconee-1 PTS oyercooling transient calculations

Transient Description

1. Oconee-3 turbine trip Siainlation of actual plant tran­sient of Marcb 14, 1980

2. Main steaa line break

3. Steam generator overfeed

4. Hot leg small break (PORV)

34-in. steam line break; all sys­tems operate as designed: steamgenerators isolated at 10 min; un­affected steam generator refilled at 15 min; restart 1 RCP per loop 10 min after attainment of snbcooling margin

Failure of feedwater pump trip on high steam generator level; all other systems opcrmte as designed

Pressurizer relief valve sticks open; ICS fails to run back main feedwater; primary coolant pumps remain on

5. Revised main steam line break

6. Maximum sustainable steam generator overfeed

7. Turbine bypass failure at hot standby

34-in. steam line break; all sys­tems operate as designed; steam generators isolated at 10 min; un­affected steam generator refilled at 15 min; restart 1 RCP per loop immediately upon attainment of subcooling margin

Reduced main feedwater pump speed to avoid pressure trips: feedwater pump trip on low steam line steam quality; all other systems function as designed

Four turbine bypass valves fail open at hot standby; turbine bypass block valves closed at 10 min

8. Pressurizer surge line small (2.5-in.-diam.) break

All systems operate as designed

9. Reactor coolant pump suction small (2.5-in.-diam.) break

10. Steam generator tube rupture

All systems operate as designed

Affected steam generator isolated after 20 min

4.3

Table 4.2 Los Alamos Oconee-1 PTS oyercooling transient calcnlations

Transient Description

1. Oconee-3 turbine trip Simulation of actual plant tran­sient of Marcb 14, 1980

2. Main steam line break 34-in. steam line break; all sys­tems operate as designed: steamgenerators isolated at 10 min; un­affected steam generator refilled at 15 min

Small-break LOCA (PORV stuck open)

Turbine-bypass valve failure (one bank of two valves)

Pressurizer relief valve sticks open; ICS fails to run back main feeduater; primary coolant pump trip

One bank of TBVs fails to reseat after openinga. SG level control failsb. SO level control does not failc. RCP restart; HPI trottled

5. Turbine bypass valve failure (two bank of two valves)

6. Small-break LOCA(2-in. hot leg break)

7. Small-break LOCA(4-in. hot leg break)

8. Rancho Seco-t3rpe transient

Two banks of TBVs fail to reseat after opening.a. SG level control failsb. SG level control does not failc. RCP restart; HPI trottled

2-in.-diam hole in pressurizer surge line; RCP trip; all systems operate as designed

4-in.-diam hole in pressurizer surge line; RCP trip; all systems operate as designed.

Initial loss of feedwater followed by runaway emergency feedwater to both steam generators

4.4

oyercooling initiators snch as steaa line breaks, feedwater overfeeds,

steaa generator tube rnptnres. and LOCA events and 2) assnaed failures

of controls and operator interventions that vonld otherwise liait systea

cooldown and repressnrization. The intent of this selection process was to

obtain accurate calculation of soae bounding cooldown events. The results

of the detailed calculations are suaaarized in Section 4.3.

The RELAP5 and TRAC codes do not predict the phenoaena of teaperature

pluaes and other related effects. These effects are iaportant because

they can yield downcomer temperatures significantly lower than the values

predicted by RELAPS or TRAC, which both assume perfect mixing. To address

this question, the predicted cold leg and downcomer flows and temperatures4 3were evaluated by T.G. Theophanous of Purdue ’ for potential of flow

stratification effects. These results are suaaarized in Section 4.4.

Section 4.5 deals with the evaluation of pressure, teaperature. and heat

transfer coefficient profiles for PTS sequences retained following the

event tree evaluation and screening process. The methods and criteria used

to screen the set of remaining events for similarity grouping are addressed.

The use of the detailed TRAC and RELAP5 data for direct extrapolation and

in a simple energy balance cooldown aodel is also discussed. The results

are presented for each major cooldown initiator, including turbine bypass

valve failure at full power and at hot standby. PORV-sized LOCA events,

main and emergency feedwater overfeed events, and steam generator tube

rupture events. The summary of the detailed TRAC and RELAPS calculations

and the extrapolated sequences in Section 4.6 provides a key for connecting

4.S

event tree results of Clispter 3.0 to the fracture mechanics results of

Chapter 5.0.

4.2 Detailed Thermal-Hydraulic Models

4.2.1 RELAP5 Model Description

This section provides a summary of the RELAP5 model of the Oconee-1 PWR

prepared at INEL. A detailed description may be found in Reference 4.1.

The RELAP5 Oconee-1 PWR steady state model is a detailed siodel of the

Oconee-1 PWR power plant describing all the major flow paths for both

primary and secondary systems, including the aiain feed train. Power-

operated relief vales (PORV). safety valves, and the emergency core cooling

system (ECCS) also are modeled. Secondary side features include turbine

bypass and turbine stop valves, safety valves, and the emergency feedwater

(EFW) system. The integrated control system (ICS) was another feature

modeled. The model contained 220 volumes, 232 junctions, and 208 heat

structures. The configurations of the full power and hot standby versions

of the model were modified as necessary to match the specifications of the

transient cases. A description of the primary system, secondary system,

feed train, and the control system are presented in the following sections.

4.2.1.1 Primary System

The noding diagrams for the RCS primary are presented in Figures 4.1, 4.2,

and 4.3.

The Oconee-1 PWR plant is a *'2-by-4 configuration," i.e., two loops each

containing one hot leg and two cold legs. The loops were designated as

4.6

-6

U1

U5 -I109

TO S U R Q f LIIfB

1 0 9

1 00

1 9 0 im17 0 176 -3

t 6 9

1 5 0

1401 -3-I711

VESSELDOWNCOMER

VESSELUPPERPLENUM710 71$

I 80 I 30

HIGH PRESSURE INJECTION

Figure 4.1 RELAP5 Oconee-1 model; primary Loop A.

4.7

SAFETY VALVES POWER OPERATED RELIEF VALVES803 801

{XI—

-2

820

800 -4

803 BOO

-S

'--- FROM 1NL2T170

Figure 4.2 RELAP5 Oconee—1 model; pressurizer system.

4.8

550

iec(rKui.AToi700 530

1.0TI X i l C T I O N 540500 530

- 200I a LOOP

COLO L z o ai LOOP COLO L > 0 251161

SOS

520CORE515-0

510-5 516-5

510-4 515-4

670-6

510-2 815-2

570-7 61 0-1 515-1

570-8505

570-9

575

Figure 4.3 RELAP5 Oconee-1 model; vessel, core flood tank and LPI system.

4.9

loop A and loop B. Each loop contained one hot leg, one steaa generator,

two pnap snction legs, two reactor coolant pnaps, and two cold legs (refer

to Figure 4.1). Loop B does not have the pressurizer surge and spray line

connections, the only difference from loop A. The pressurizer surge line

and pressurizer were attached to the hot leg in loop A (see Figure 4.2).

Each cold leg contained a high-pressure injection (HPI) port.

The RELAP5 vessel model shown in Figure 4.3 consisted of several components

describing the various vessel flow paths. The RELAP5 vessel included an

inlet annulus, downcomer, lower plenum, core, core bypass, upper plenum,

upper head, and a vent valve. The use of a single downcomer region

prevented prediction of nonsymmetric temperature or flow effects due to the

resultant mixing of the four cold leg streams.

The eight reactor vessel internal vent valves between the upper plenum and

downcomer inlet annulus were modeled with a single RELAPS servo valve. A

servo valve uses the output of a RELAP5 control variable to determine the

open area of the valve. The control variable was designed to calculate

a valve flow area as a function of the differential pressure across the

valve. Because the range of differential pressures over which the valve

position changes is small, it was necessary to smooth the calculated

differential pressure to prevent valve chattering. Without smoothing,

the valve position responded instantaneously to the differential pressure

across it. With smoothing, the change in valve position in a time step

was limited, thus preventing excessively quick opening and closing of

the valve and qualitatively simulating the response time of the flapper

valves. Within the limitations of the thermal hydraulic models, the model

4.10

of the vent valve used in the RELAP5 model is the best representation of

the Oconee-1 reactor vessel vent valve presently available.

Also included in the primary system were the low-pressure injection (LPI)

system, the core flood system, PORV, and safety valves. The LPI and core

flood systems were connected to the vessel inlet annulus. The PORV and

safety valves were connected to the top of the pressurizer. Table 4.2

summarizes the relationship between the physical components of the Oconee-1

LPI, core flood systems, PORV, and safety valves and the corresponding

mathematical components of the RELAP5 model.

The RELAP5 nonequilibrium model was applied to all volumes in the

primary system except for the accumulator where the accumulator model was

applied. The wall friction model was applied in all primary volumes.

Centrally located junctions for horizontal stratification were applied to

all horizontal junctions. The choking and two-velocity models were applied

at all primary junctions and an inertial solution was calculated at all

junctions.

Heat structures were used to represent heat transfer and stored energy

from fuel rods, steam generator tubes, loop piping, vessel wall, vessel

internals, pressurizer wall, pressurizer surge line, and pressurizer

heaters.

4.2.1.2 Secondary System

The RELAPS model of the loop A steam generator secondary is shown

schematically in Figure 4.4. Loop B has an identical noding structure.

4.11

Ufl

EFW Train ess

SRV SOT

TBV

TSVesi — OF L*n.Tij

SSO-2 ) 3SS-1 ' ' 8 4 6 *zzzzkzzzz iZZ2j‘

SSO-l

MFW Train TTS-a

S 0-4■tv LT1.T4F

ao-t

ISS

Figure 4.4 Loop A steam generator and steam line.

4.12

Originally the startup and operating levels were calculated based on the

collapsed downcomer liquid level. Some early calculations were performed

using this approach. For calculations presented in this report, the levels

were based on calculated static pressures and fluid temperatures at the

locations corresponding to pressure and temperature taps in the Oconee-1

steam generators. The calculated temperatures and differential pressures

were smoothed in a manner consistent with the actual instrumentation

system. The improved method of level calculation significantly affected

the sequence of events in the INEL revised main steam line break transient,

as discussed further in Section 4.3, and, in general, improved the behavior

of emergency feedwater injection, which is controlled on level. The RELAPS

options used in the secondary system follow. The nonequilibrium option

was applied to all volumes in the secondary system, a change from the

equilibrium option used to perform the initial calculations with this

model. Difficulties encountered with secondary behavior during the initial

portion of the main steam line break calculation were overcome, allowing

the nonequilibrium option to be used.

This change resulted in a more satisfactory behavior of the secondary

system during periods of emergency feedwater injection. The wall friction

model was applied to all secondary volumes. Centrally located junctions

for horizontal stratification were applied to all horizontal junctions.

The choking and two-velocity models were applied to all junctions, and an

inertial solution was calculated at all junctions.

Heat structures were used to simulate the stored energy contained in the

secondary shell wall, piping, and internals.

4.13

4.2.1.3 Feedwater System

The purpose of the feedwater system is to supply demineralized/deaerated

snbcooled water to the A and B steam generator secondary inlets. The water

is heated and pressurized from 305 K (SK)°F) and 0.01 MPa (14.5 psia) to

511 K (460°F) and 6.55 MPa (950 psia). Figures 4.5 and 4.6 and Table 4.3

show the modeling arrangement of the feedwater trains.

The RELAP5 options used in describing the feedwater system include the

nonequilibrium and wall friction models. Centrally located junctions were

applied to all horizontal junctions* and choking and two-velocity models

were also applied at all junctions.

Heat structures were used to represent the high- and low-pressure heaters

and the piping wall metal masses. The feedwater heaters were modeled

using the appropriate tube bundle surface areas. The energy contributed

to the feedwater from the heater secondaries was modeled using the heat

structure energy source option in RELAP5. The piping was modeled by first

calculating the applicable metal volume, then adding the equivalent metal

thickness to the appropriate heat structure. Heat structures representing

several components were combined and added to selected components to reduce

the computer storage requirements.

4.2.1.4 Control System

The Babcock & Wilcox integrated control system (ICS) is a comprehensive

system that controls all power generation operations of the Oconee-1

plant. The models developed for the pressurized thermal shock program

study of the Oconee-1 plant comprise only three portions of the overall

4.14

E H E A T E R D R A I H D H E A T E R D R A I N

744 750

734 730:730

748743

746,Ly 7 y 7 j / /

740736

/ 7 / f J-T

752

H O T A T E L LP U M P

B O O S T E RP U M P

-e-H-•tn

M A I N F E E D W A T E R P U M P A

M a i n f e e d w a t e rP U M P B

757-Kl- STARTUP

ANDMAINFEEDVALVES

754

762760

756

761756

/ 7 7 7 / X / / / 7 7L

764

//7//y////7

766 i

763 760

Figure 4.5 RELAP5 Oconee-1 model; feedtrain from hotwell to startup and main feed valves.

U O T O R D H I T S H E M E X Q S H C T E E E D T J I T E R

T I T R B I H E D H I V J j : E M E R Q E H C T E E E O T A T C R

<S3-Tn M

S T E A U G E X E S A T O R K S E C O N D A X r U P P E R S T E A M D O M E

77 < 774

7 77

774

S T E A M O S K E R A T O R A D O R N C O M S R

/ / yy-r-ry-.\ 744

— J X . !

3 T S A K G B K C S A T O R1

7 f 0 ~ t 1 7 S 0 > S

................. — , - t II 1L.

B D O l T N C O M Z f t

M O T O R D R I V E N E M E R G E H C T r C S D V A T E R

954904

909 90S — f \ j --- *94

99 a

S T E A M 3 I H E R A T 0 R a S E C O N D A R Y U P P E R S T E A M D O M E

T U R B I N E D R I V E N S M S R O E N C T P E E D V A T E R

Figure 4.6 RELAP5 Oconee—1 model; feedtrain from startup and main feed valves to steam generator, crossover, and emergency feedwater system.

4 . 1 6

Table 4.3 Correspondence betveen physical components and the RELAP5 mathematical components in the Oconoee-1 feedtrain model

Physical Component RELAP5 Component

HotwellHotwellDemineralizer and deaerator system Booster pxunpLow-pressure F and E heaters

E heater drain Low-pressure D heaters D heater drain Low-pressure C heaters A main feedwater pump

A main feedwater piuap discharge line B main feedwater pump inlet line B main feedwater pump Main feedwater pump discharge line Main feedwater pump header

A and B heater train number 1 A and B heater train number 2 High-pressure heater header A and B startup and main feedwater

control valves Steam Generator A control valve header

730734736

738740

742,744746748, 750752ISA

156. 757758760761, 762763

764 766 768770, 771, 772, 773

774, 775

Steam generator B control valve header Steam generator A feedwater header Steam generator B feedwater header Steam generator A feedwater crossover Steam generator B feedwater crossover

776, 777 778, 782 780, 784850, 851, 852, 853, 854 950, 951, 952, 953, 954

4 . 1 7

control system: 1) turbine bypass control, 2) feedwater control, and

3) emergency feedwater control, the EFW control being separate from the ICS.

The model follows the description of the ICS given in Chapter 2.0, Section

2.2.3. The full complement of reactor protection trips and safety system

actuation signals was included in the model.

4.2.2 TRAC Model Description

This section provides a summary of the TRAC model of the Oconee-1 PWR

prepared at LANL. A detailed description may be found in Reference 4.2.

The Oconee-1 model developed for the PIS study represented the most

comprehensive nuclear power plant modeling assembled to date for use with

the TRAC code. The model contains a primary side, a secondary side, and

a complex control system consisting of both trips and controllers.

4.2.2.1 Primary System

The noding diagram is presented in Figure 4.7, the primary side of the

Oconee-1 model. It consists of the three-dimensional vessel, two hot legs,

two once-through steam generators, four cold legs, and soae parts of the

emergency core cooling system (the low-pressure injection system was not

modeled).

The volumes, elevations, and pipe lengths from the Oconee-1 plant are

closely matched in the model. The wall areas and thicknesses of the

primary piping also are modeled so that the thermal response of the piping

is predicted. Heat transfer from the pipe walls to the environment also

is allowed.

4.18

ACCUMJLATOa ACCUMULATOD

ntlUR

VESSEL »9J5L_J

LOOP B LOOP A

figure 4.7 TRAC Primary-side model for Oconee-1.

4 . 1 9

The thxee-diBensionel vessel is nade vp of 96 cells arranged so that

the vessel is divided into eight axial levels, tvo radial rings, and six

azimuthal segments. The lower plenum is made up of one level, the core

of four levels, the upper plenum of two levels, and the upper head region

of one level. The two radial rings are divided so that the core region

is bounded by the inner ring and the downcomer annulus is modeled in the

outer ring.

The vessel metal structures and wall laasses are modeled by assigning a

representative thickness and area of a heat slab to each three-dimensional

cell. Using these heat slabs, the stored energy of the vessel structure

is approximated. The thermal conductivity for each heat slab is calculated

by assigning five nodes across each slab thickness. These nodes are spaced

so that they are closer together on the fluid side of the slab. There

is no heat transfer through heat slabs between cells; that is, each cell's

heat slab is isolated from any other cell's heat slab except through the

fluid-dynamic coupling.

The six azimuthal divisions were chosen to allow for the angle and

separation of the penetration of the hot and cold legs. Also, the

accumulator injection ports were modeled close to their exact positions

(both axially and azimuthally) in the vessel downcomer region.

With only one radial division for the inner portion of the vessel modeled,

the circulation of hot water rising from the core into the upper head and

descending out the hot legs is lost. Without finer noding of the vessel,

the upper head is effectively isolated from the rest of the vessel in

many circumstances. To alleviate this problem, a connection was assumed

4.20

between the npper head and the hot legs so that about one-third of the

nornal steady state flow passes through the upper head. This upper-head

tee connection influenced the movements of steam voids between the upper

head and the candy canes of the hot legs. This behavior is most evident

in the main steam line break sequence suauaarized in Section 4.3.

The vessel includes vent valves that are modeled to allow flow from the

upper plenum directly to the downcomer. This flow path is only available

when the upper plenum pressure is higher than the downcomer pressure. A

composite vent valve made up of one-sixth the total vent-valve area is

modeled in each azimuthal cell of the inner radius of axial level 7. The

vent valves are fully open when the pressure drop between the upper plenum

and downcomer exceeds 0.12 psi.

The loop A and loop B hot legs are modeled symmetrically except for the

surge line connection to the loop A candy cane. The candy canes represent

the highest elevation in the system. The surge line includes a "small-

break" that is activated for the small hot leg break transients.

The pressurizer is modeled with a very small cell at the bottom and two

small cells at the top. This is necessary to allow correct fluid conditions

either to enter or leave the pressurizer.

Pressure relief for the primary system is provided by a single PORV at the

top of the pressurizer. This valve supplies adequate relief for the cases

in which secondary cooling is provided and the reactor has tripped.

A complete model was developed for BSW once-through steam generators. The

primary side of the steam generator is made up of 12 cells, whereas the

4.21

secondary side nses 26. Heat transfer from the priaary occurs through

the steaa generator tubes to the secondary coolant. Cells 2 through 11

(Figure 4.7) represent a coaposite of the voluae inside and wall area of

all tubes, and it is in these cells that heat transfer froa the coolant

to the walls of the tubes occurs. Cells 1 and 12 aodel the upper and

lower plenuas. The wall area and thickness of the plenuas are aodeled so

that the heat capacitance and heat transfer of the external wall can be

calculated.

The secondary of the steaa generator is divided into four coaponents

(Figure 4.8); two aodel the tube-bundle region, one aodels the downcoaer,

and the final one aodels the steaa-outlet annulus. The tube bundle region

is aade up of 10 cells (SG coaponents 12-1 and 12-2 for loop A and 2-1 and

2-2 for loop B in Figure 4.8). These cells aodel the total voluae and the

tube wall area for the region between all the steaa generator tubes, but

aodel the heat transfer characteristics of a unit cell of tubes. The top 4

of these 10 cells coaprise the superheated-steaa region of the aodel during

noraal full-power operation. The connection at the top cell of the tube

bundle region is for the eaergency feedwater (EFW) flow and the realigned

aain feedwater flow. This connection closely aiodels the correct plant

geoaetry so that any flow froa the ''upper header" is correctly injected

into the tube bundle.

The steaa generator downcoaer consists of seven cells (SG coaponents 12-3

and 2-3 of Figure 4.8) plus one cell for the aain feedwater injection and

one cell for the aspirator port. During noraal operation, the downcoaer

condenses enough superheated steaa drawn through the aspirator port to heat

4.22

Sleain Line A

hOOJ

- a i - iz o z r ~ i z i . u : i t ^ i l j t i ■«m y < k>i [ 3 0

B l i e n 'f i I 3 ( Z I T 7 924 E O 920 ^

10 & rfsJ .

e^cnsi aooTD V

©

Sticn

ffiDC o n d a n a o r 8 3 0

surcv1910 l2Xtl312 CJaoeBJO] soa:3 57M PCVXr]504tIXIl«HI 1902

32) 6i) (20

, Slaam Lin* B //0 T 3 :i. o 41 r r .T~E~ r ~ iz iz i : :r ! 0

■ ' U fR)4 C C X 2 B 0 3 C ® ]

TSVH otw tll

: 88CrS]B7lTDV

CPW PumpEPW LineI S38 m B 1 T \ 6 l ~ 5 1 r - f 3 ~ l Z I 1/1 937 t Z

I4 7 l« IE K * rV

JO; (85rT~r~iB03 7(1 (470ifTT5T~

B" HP

H3923A " H P

H i a l e rsuix:v131 I907I7 YT1909 Heeler Pumpe:3 47

MFcv n5 0 3 \ i ^ l \ 0 0 2 \ ] flO I

XT’ l PHntar «S. lUalar ,Z5,Hlr U*Drain QS Dr HIrV L P

690 -* T ’ L P — -l l a a l a r ^ 0 . P u m p a H o l w e l l P u m p a

Figure 4.8 TRAC Secondary-side model for Oconee-1.

the main feedwater to saturation tenperature prior to entry into the tube-

hnndle region. The final six stean generator secondary cells model the

steaa exit annulus. The outlet froa this annulus is near the midpoint of

the steaa generator, close to the actual location in the plant.

The SG water levels were modeled using the best available methodology, a

collapsed liquid level calculation. This method is adequate for transients

in which relatively slow changes in the secondary side occur, but it can

generate wide discrepancies relative to the pressure tap calculation used

in the RELAP5 model for rapid changes, such as in a MSLB transient.

All four cold legs of the plant were aodeled. These legs each consist

of a loop seal (lowest priaary-loop point), a reactor coolant pump (RCP),

and the HPI connection. The HPl nozzles are positioned closely to their

correct height and distance froa the vessel entrance. The RCPs are speed

controlled during steady state operation to obtain the required mass flow,

but their steady state speed is maintained fixed while they are running

during a transient. During noraal operation, the four cold legs of this

model have symmetric flows.

Two major coaponents of the ECCS included in this aodel were the HPI system

and the accumulators (core flood tanks) . If a transient were to be run

that caused the primary pressure to fall below the loir*pressnre injection

system (LPIS) set point, then the LPIS also would have to be added to the

mode1.

The HPI system was modeled as four boundary conditions that can inject

283 K (50^F) water into the priaary through the four side nozzles of the

4.24

cold legs. These nozzles are located so they enter the main cold legs

from the side at an elevation somewhat higher than the centerline of the

cold/hot legs. The pressure-dependent flow rate of the two loop B ports

is identical, as is also the case for loop A, but the loop A capacity is

greater than that of loop B.

There is an accumulator tank for each loop that allows emergency coolant

to flow directly into the downcomer region in axial level 7 of the vessel

(Figure 4.7). The accumulator flow is controlled by check valves so that

when the primary pressure falls below the accumulator-tank pressure, the

check valves open. The initial accumulator pressure was ~4.2 MPa (~610

psia) with a coolant temperature of 305.4 K (90°F).

4.2.2.2 Secondary Side

All major components of the secondary side are modeled except for the

turbine generator equipment and various valves that were not necessary for

any transients of immediate interest. With the exception of the vessel,

the secondary side required much more modeling detail than was necessary

when only the primary system was modeled.

In this discussion, the feedwater train describes the secondary-side

modeling from the condenser to the tee, where the feedwater is divided

between the two steam generators. This section of the modeling takes the

fluid discharge from the turbines and raises it to the temperature and

pressure at which it is delivered to the steam generators.

The condenser is modeled as a large tank with a very large wall area. The

thin walls have a high thermal conductivity and a constant temperature heat

4.25

sink on the outside surface. This aodel fully condenses the incoming steaa

from either the turbine exhaust or the turbine bypass system.

The hotvell is an even larger tank used for the collection and storage

of the condensate. The lowest system pressure and temperature occur in

this component. Cell 1 of the hotwell actually represents the volume and

coolant inventory of the upper surge tank. It is included to reduce the

complexity of the model while still providing an estimate of the available

hotwell inventory. The coolant supplied to the emergency feedwater system

is taken from the hotwel1/upper surge tank combination.

The hotwell pump (component 51) includes the demineralizer/aerator section

of the feedwater train. The model accounts for the effects of this section

by including additional frictional losses and heat addition to the coolant.

Each feedwater heater is modeled to achieve a feedwater temperature rise

close to the design value for that heater. In addition, the model includes

a time-dependent estimate of the feedwater-heater heat capacitance.

The two parallel MFW pumps of the actual plant are combined into a single

pump for this model. This is a variable speed pump with the speed

determined by the ICS.

The coolant flow from the feedwater train splits to provide flow to the

steam generator-control valve section of each major loop. The loop A and

loop B flow-control valves are identical. The ICS varies both NFV pump

speed and feedwater control valve position to optimize control. Additional

details of the model are available in Reference 4.2.

4.26

The EF¥ system is modeled so that it takes water from the hotwell and

delivers it to the E F W s of both steam generators. The EFW pnmp is modeled

as a composite of the tnrbine-driven and motor-driven pnmps in the actual

plant and therefore, has a large capacity. The EFW is delivered to a

tee (component 152, Figure 4.8) that splits the flow between the two steam

generators. If both EFWVs are open, the EFW flow is symmetrically split

as long as the secondary pressure of the two steam generators is equal. If

only one EFWV is open, the full flow available is delivered to that steam

generator. The EFW flow stops if the hotwell inventory has been depleted.

The steam line for steam generator B is longer than that of steam generator

A. Other than this difference, the steam lines and their valves are

identical. A pressure boundary condition models the steam flow existing

the secondary into the turbine inlet. During steady state operation, the

steam mass flow is modeled to reenter the secondary as boundary condition

inlets to the condenser and the two heaters drain. Following a turbine

trip, the turbine stop valves (TSVs) close the steam lines. If any pressure

relief from the closed steam lines is necessary, steam is released through

the turbine bypass valves into the condenser. For a normal reactor/turbine

trip transient, the steam relief from the turbine bypass valves is adequate

so that modeling the main steam safety valves is not necessary.

4.2.2.3 Control Systems

The TRAC model included the integrated control system (ICS) functions

discussed in Chapter 2.0, Section 2.2.3, namely, turbine bypass valve

control, feedwater valve control, and main feedwater pump control. The

4.27

full coBpleBent of reactor protection trips and safety systeB actuation

signals was included in the Bodels as described in Reference 4.2.

4.3 Results of Detailed Calculations

4.3.1 RELAP5 Calculations

The sequences siBulated by the RELAP5 Bodel are listed in Table 4.1.

Detailed discussion of the transients and the results are available in

Reference 4.1. Suaawry descriptions of the transients are provided here to

provide a context for discussion of sequence extrapolation in Section 4.5.

The results for the Oconee-3 feedwater transient are oaitted in reference

4.1 and are likewise not included here. A suaaary of all transients

discussed here and in Sections 4.3.2 and 4.5 is provided in Section 4.6

and Table 4.25.

4.3.1.1 INEL Original Main Steaa Line Break

A description of the transient appears in Table 4.4. The sequence is

identical to that for the revised aain steaa line break presented in Section

4.3.1.4 except for the reactor coolant (RCP) restart and high-pressure

injection (HPI) throttling criteria. For this sequence, one RCP per loop

is to be restarted 10 ain after attainaent of 28 K (50°F) subcooling in

both hot legs, and HPI is not throttled. In the revised sequence, the

RCP restart is iaaediate upon attaining 42 K (75°F) subcooling, and HPI

is to be throttled to aaintain 28 to 56 K (50** to lOO^F) subcooling.

Results of the calculation and extrapolations to 2 h are shown in Figures

4.9 through 4.11. Figure 4.9 shows the reactor vessel downcoaer pressure

4.28

Table 4.4 INEL original main steam line break transient scenario

1. Reactor trips, coincident vith break of 0.86 m (34 in) steam line

2. Turbine trips; TSVs close

3. ICS functions as designed

4. Protection systems on hotwell, condensate booster; NEW pumps function as designed

5. HPI actuates at set point of 10.34 MPa (1500 psig)

6. Operator trips RC pumps 30 s after HPI actuation

7. EFV pumps start when low MFW pump discharge pressure is sensed

8. MFW/E^ system attempts to maintain 6.1 m (240 in.) steam generator level

*9. Core flood tanks actuate at set point

10. LPI actuates at set point•a

11. Operator isolates feedwater to affected steam generator 10 min into the transient

*•*12. Operator restarts one RC piunp in each loop 10 min after attaining28 K (50^F) subcooling in the hot legs

13. PORV opens at set point of 16.9 MPa (2450 psig)*14. SRVs open at set point of 17.2 MPa (2500 psig)

15. PORV/SRVs reseat at their set points of 16.5 MPa (2400 psig)

16. Pressurizer goes water-solid

17. EFW surge tank capacity of 272544 liters (72,00 gal) is exhausted; the two motor-driven EFW pumps trip

*18. Turbine-driven EFW continues to draw from hotwell

* Event is phenomenologically dependent.• a Five times a typical time for operator action, based on simulator

experience.

Two times a typical time for operator action, based on simulator experence.

4.29

20— CALCULATED- • EXTRAPOLATED

-2300

UiCKZ3(A(OLUqe:a.

-1500Ui3_iO>

-1000

1000 2000 3000 4000 5000Time (s)

6000 7000 8000

(DQ.

3O)v>o

9£3o>

Figure 4.9 Main steam line break, RV downcomer pressure.

580CALCULATEDEXTRAPOLATED

--550

-500

520cr

500

4800 2000 3000 4000 5000 7000 80006000

9u.3o«a.£0>

3cr

£3O>

T im e (s)

Figure 4.10 Main steam line break, RV downcomer fluid temperature.

4.30

30

20 ■<u Oo I u Etn V C Vw/o

— CALCULATED h - - - EXTRAPOLATED

-5000

-4.000 ^

10 ■■

a49X

o a y -u_LU I O cm'

-3000 O

-2000

iLto \ X 3

-1000LU X

1000 2000 3000 4000 5000Time (s)

6000 7000 8000

Figure 4.11 Main steam line break, RV downcomer inside surface beat transfer coefficient.

4 . 3 1

response. The minimniD pressure calculated vas 5.02 MPa (728 psia) and

the maximum was 16.99 MPa (2465 psia), the opening set point of the power-

operated relief valve. Figure 4.10 shows the reactor vessel downcomer

fluid temperature. The minimum temperature calculated was 482 K (407*^ F).

The reactor vessel wall inside surface heat transfer coefficient is shown

in Figure 4.11. The low values (for example, at 500 s) correspond to

periods of natural circulation flow, and high values correspond to periods

when reactor coolant pumps are operating.

4.3.1.2 Steam Generator Overfeed

A description of the transient is in Table 4.5. This sequence is transient

number 53 (INEL3) in Table 4.25. The scenario differs from that of the

maximum sustainable overfeed transient (presented in Section 4.3.1.5) in

the availability of feed train protection functions. For this sequence,

the protection functions, primarily low suction pressure trips on the feed

train pumps, were available, and as a result the main feedwater pumps were

tripped shortly after the transient was initiated. This sequence further

differs from the sequence in Section 4.3.1.5 in that reactor coolant pump

power is not tripped off by the operator.

Results of the calculation and extrapolations to 2 h are shown in Figures

4.12 through 4.14. Figure 4.12 shows the reactor vessel downcomer fluid

pressure response; the minimum pressure calculated was 8.92 MPa (1293

psia). The maximum pressure calculated was 16.99 MPa (2465 psia), which

corresponds to the power-operated relief valve opening set point pressure.

The minimum calculated downcomer fluid tmaperature was 505 K (450*’F), as

shown in Figure 4.13. The reactor vessel wall inside surface heat transfer

4.32

Table 4.5 Stean generator overfeed transient scenario

#

1. Reactor trip, tnrbine trip. TSVs close

2. TBVs open and safety valves open and reseat at set points

3. Full MFW flow continues

4. HPI actuates at set point of 10.34 MPa (1500 psig). but operator doesnot trip RCPs

5. MFW pump trip on steam generator high level fails to occur

6. Steam generators fill*7. Core flood tanks actuate at set point

8. IPI actuates at set point

9. Protection systems on hotwell, condensate booster, and MRW/EFW pumps function as designed

10. Main steam lines fill with water

11. TBV closed at its set point on loss of condenser vacuum

12. EFW pumps start per low MFW pump discharge pressure set point

13. EFW flow controlled at steam generator level set point of 0.61 m (24 in)

14. PORV opens at set point of 16.9 MPa (2450 psig)

15. SRVs open at set point of 17.2 MPa (2500 psig)

16. Pressurizer relief valves reseat at set point of 16.5 MPa (2400 psig)

17. Pressurizer goes water-solid

*Event is phenomenologically dependent.

4.33

20000 CALCULATTO EXTRAPOLATED

^ 18000•2500Q.

16000LUcr

-2000

12000

-150010000

800072003600 54000 1800

Time (s)

Figure 4.12 S.G. overfeed, RV downcomer pressure.

xnO.

3nm9

580— CALCULATED- - EXTRAPOLATED

k.3 -550560 ■ak.oa.Eo> 540

•5003cr

5209E3O>

5000 1800 3600 7200

Time (s)

Figure 4.13 SG overfeed, RV downcomer fluid temperature.

«k-3Oi-oa.Eo

3O'

«£_3O>

4.34

F7000 CALCULATTD EXTRAPOLATED

■6500

35-6000

NE

-550030

■500C

-4.500251800 3600

TFme (s)5400 7200

® 1o I

x: a

• E CD

oa>

Figure 4.14 SG overfeed, RV dovmcomer inside surface heat transfer coefficient.

4.35

coefficient, shown in Figure 4.14, represents forced convection conditions

throughout the calculation. The variations observed in the coefficient are

prinarily due to changing fluid densities and pressures as the transient

proceeded.

4.3 .1.3 Hot Leg Snal1-Break Transient

The sequence is initiated by a stuck-open power-operated relief valve. The

operator is assuned not to trip power to the reactor coolant pumps. The

transient is described in Table 4.6. This sequence is transient number

52 (INEL2) in Table 4.25.

Results of the calculation and an extrapolation to 2 h are shown in Figures

4.15 through 4.17. Figure 4.15 shows the reactor vessel downcomer fluid

pressure response. The minimum calculated pressure was 8.68 MPa (1259

psia). As shown in Figure 4.8, the minimum downcomer fluid temperature

was 545 K (521*’f ) and occurred at 2 h the end of the extrapolation. The

extrapolated primary pressure at 2 h is 11.38 MPa (1650 psia). The heat

transfer coefficient on the inside surface of the reactor vessel downcomer

wall is extrapolated to drift downward as fluid properties change, as shown

in Figure 4.17. The coefficient represents forced-convection conditions

throughout the calculation.

4.3.1.4 Revised Main Steam Line Break

The revised main steam line break has the same specification as the LANL

main steam line break base case (Section 4.3.2.1). This sequence is

transient 51 (INELl) in Table 4.25. The revised case differs from the

original INEL case in the reactor coolant pump (RCP) restart and the high-

4.36

Table 4.6 Hot leg small-break transient scenario

1. Small-break loss-o£-coolant accident

2. Keactor trips; tnrbine trips; TSVs close

3. HPI actuates at set point of 10.34 MPa (ISOO psi)

4. IBVs/SRVs in secondary function as designed

5. ICS fails to run back MFW

6. NFV pumps trip on high steam generator level

7. EFW system functions as designed

8. Core flood tanks dump; LPI system actuates

*•

Size: 2.1368 z 10 ^ m^ (0.023 ft^); location: pressurizerrelief valve

Event is contingent on size of break

4.37

16000

Ojst UOOO

Uicr3t/y(/y 12000Uicrcu

O10000

8000

— CALCULATED EXTRAPOLATED

| X _ ..........................

2200

2000

-1800

na.

3-

1600 *» V u a.

huoo

h120O1000 2000 3000 AOOO 5000

Time (s)6000 7000 SOOQ

Figure 4.15 Hot leg small break, RV downcomer pressure.

580

cr3H-<01 Uicr2

570

560

3O

Ui23_lO>

550

540

— CALCULATED EXTRAPOLATED

580 ^

560

540

520

UIQC3I—<cruia.2Uia3a

23-JO>

1000 2000 3000 4000 5000Time (s)

6000 7000 8000

Figure 4,16 Hot leg small break RV downcomer fluid temperature.

4.38

CALCULATED- - EXTRAPOLATED ■5000

28

s> ^ O I

l- -4000

206000 7000 8000tooo 3000 4000 50000 2000

c(D

•*- •® IO Io*V

•*- XO X ^ ffl

ooX

Time (s)

Figure 4.17 Hot leg small break, RV downcomer inside surface-heat transfer coefficient.

4.39

pressure injection (HPI) throttling criteria. In this case, the restart

of one RCP per loop is iamediate upon attaining 42^C (7S^F) snbcooling,

and HPI is throttled to aaintain snhcooling of 42 - 14*^0 (75 - 25^F).

The sequence is initiated by a 200% double-ended rupture of a aain steaa

line on one steaa generator. All autcaatic plant functions are assuaed

to be operative. Operator actions are assuaed to trip reactor coolant

puap power 30 s after initiation of high-pressure injection, terainate

all feedwater and turbine bypass on both steaa generators at 10 ain, and

reactivate eaergency feedwater and turbine bypass to the unaffected steaa

generator at 15 ain.

Table 4.7 gives the sequence of events for the calculation. Figures 4.18

through 4.20 susuaarize the results of the calculation and extrapolation to

7200 s.

As shown in Figures 4.18 and 4.19, the calculated ainiaua reactor vessel

downcoaer aixed fluid teaperature was 494 K (429°F) and the calculated

aaxiaua subsequent fluid pressure was 16.99 MPa (2465 psia). The downcoaer

heat transfer coefficient is given in Figure 4.20.

The calculation of downcoaer fluid teaperature was particularly sensitive

to the requireaent in the scenario to restart reactor coolant puaps upon

attaining 42 K (75°F) subcooling in both hot legs. This requireaent was

aet 300 s into the transient, and the restarting of the puaps caused the

ainiaua downcoaer teaperature to be much warmer than if the puaps had not

been restarted. Since the attainaent of subcooling is sensitive to hot leg

asyaaietry and because a one-diaensional coaputer aodel such as RELAP5 will

4.40

Table 4.7 Revised MSLB sequence of events

Event

Time from Start of Transient

(s)

Reactor trip; tnrbine trip break opens 0

Main feedwater pnmps tripped on high level in affected steam 0.3generator

Emergency feedwater tripped on, based on low main feedwater pnmp 4.4discharge pressure

HPI tripped on, based on low hot leg pressure 5.3

RC pnmps tripped (30 s after HPI initiation) and main feedwater 35.3rerouted to emergency feedwater header

75°F snhcooling attained in both hot legs, 2 RC pnmps restarted, 300 and HPI throttled to maintain 50-100°F snhcooling

Unaffected steam generator level recovered to 240 in; main 320feedwater to this steam generator is terminated and emergency feedwater is throttled to maintain 240-in. level

Restarted RC pnmps are up to full speed 360

Hotwell surge tank is empty: motor-driven emergency feedwater 513is terminated to both steam generators

Per scenario, all main and emergency feedwater and tnrbine 600bypass capability is terminated

Per scenario, tnrbine bypass and tnrbine-driven emergency 900feedwater is made available to the unaffected steam generator

Last time HPI is injected because snhcooling is greater 1992than lOO^F after this time

Pressurizer level reaches top 2354

PORV opening set point pressure reached 2432

Calculation terminated 2697

4 . 4 1

20000— CALCULATED - - EXTRAPOLATED

■2500

P 15000•2000

■1500k. 10000O.

■1000

50006000 8000400020000

tnQ.

3tntnVu0.

Figure 4.18 Revised MSLR, extrapolated pressure in RV downcomer.

600- CALCULATED- EXTRAPOLATED

-600» 580

■550

■500

cr 520

500

480800060002000 40000

«k.3Ok.oaEo

3tr

E_3O>

Figure 4.19 Revised MSLB, extrapolated fluid temperature in RV downcomer.

4.42

not predict this asymmetry, the timing of the pump restart is uncertain.

The effect of this and other specific uncertainties on minimum downcomer

fluid temperature has been estimated to reduce the best estimate minimum

downcomer fluid temperature to 462 K (372°F) with a lower uncertainty bound

of 415 K (287°F).e See Reference 4.1 for further details.

4.3 .1.5 Maximum Sustainable Overfeed Transient

The maximum sustainable overfeed transient employed a reduced MFW pump

speed to circumvent the automatic feedwater system protection features

(i.e., NFV pump trip on low suction pressure) that tripped the feedwater

system early in the steam generator overfeed transient (Section 4.3.1.2).

The maximum sustainable overfeed sequence is transient 56 (INEL6) in Table

4.25.

The transient was initiated from full-power steady state conditions (nominal

temperature and pressure). The pressurizer heaters and spray operate as

designed. The transient was initiated by a turbine trip that tripped

the reactor and closed the turbine stop valves. Decay heat was assumed

to be at the ANS standard rate. Instead of running back flow, the main

feedwater system continued to supply the maximum sustainable flow to both

steam generators without a trip from the component protection feature to

the main feedwater pumps. It was assumed the main feedwater pump trip on

steam generator high level failed to occur, allowing both steam generators

to fill completely. The main feedwater pumps were eventually tripped on

low steam quality in the main steam lines.

*It should be noted that the adjustment of the downcomer temperature to reflect the uncertainty is inconsistent with the uncertainty analyses de­scribed later in this report.

4.43

Table 4.8 gives tbe sequence of events calculated for the transient. At

the teraiination of the calculation, systea behavior had been established

such that extrapolation of the dovnconer pressure, temperature, and vessel

inside wall heat transfer coefficient to 7200 s was possible, as shown in

Figures 4.21 through 4.23. The lowest downcomer liquid temperature in this

time frame was 500 K (440^F). Subsequent to this minimum temperature, the

maximum downcomer pressure was 16.99 MPa (2465 psia).

4.3.1.6 Turbine Bypass Valve Failure at Reactor Hot Standby

The turbine bypass valve failure at reactor hot standby is listed as

transient 57 (LANL7) in Table 4.25. The RELAP5 full-power model was

converted to hot standby conditions by the changes listed in Reference 4.1.

As specified, the realignment of MFW to the emergency feedwater headers was

locked out for this calculation.

The transient was initiated with the reactor at hot standby conditions.

At zero time, all four turbine bypass valves (two on each steam line) are

assumed to fail open, and all automatic plant systems are assumed to be

operative. Operator actions are assumed for tripping reactor coolant pump

power 30 s after high-pressure injection begins and closing turbine bypass

block valves at 10 min.

Table 4.9 gives the sequence of events for the calculation. Figures 4.24

through 4.26 summarize the results of the calculation.

As shown in Figure 4.25, the minimum calculated reactor vessel downcomer

fluid temperature was 387 K (237°F) near the end of the transient. The

maximum calculated reactor vessel downcomer pressure was 16.99 MPa (2465

4.44

Table 4.8 Mazimim sustainable overfeed transient sequence of events

TimeEvent (s)

Turbine trip, reactor trip, turbine stop valves close, main 0.0feedwater pumps run back to 490 rad/s (4675 rpm); secondary pressure increased to turbine bypass and; safety relief valve set points. Feed train beater drains begin to close; pressurizer begins to drain

Heater drains closed 5.0

Steam generator 6 secondary pressure dropped below safety relief 25.0valve set point; valves close

Steam generator A secondary pressure dropped below safety relief 28.0valve set point; valves close

Pressurizer liquid level dropped below beater cutoff set point; 35.0beaters latcbed off

Steam generator B secondary completely liquid-full and steam line 240.0commenced to fill

Steam generator A secondary completely liquid-full and steam line 250.0commenced to fill

Primary pressure dropped below bigb-pressure injection set point 269.0and bigb-pressure injection flow was initiated

Vessel upper bead began to void 275.0

Reactor coolant pumps trip; feed flow realigned to EFW header; 299.0main feed valves close

Steam generator B turbine bypass valves close 341.0

Steam generator A turbine bypass valves close 350.0

Void in steam line B dropped below 20%; main feedwater pumps 417.0trip off

Void in vessel upper bead collapsed 434.0

Pressurizer began to refill 448.0

Primary system began to repressurize 524.0

4.45

Table 4.8 (continned)

TimeEvent (s)

Steam generator A secondary pressure reached turbine bypass 930.0valve set point and valves crach open

Primary pressure reached power-operated relief valve opening 1054.0set point and cycles around set point

Pressurizer becomes liquid-solid 1079.0

Steam generator B secondary pressure reached turbine bypass 1424.0valve set point and valves crack open

Transient terminated; system pressure stabilized at power- 1695.0operated relief valve opening set point; primary temperature was slowly increasing

4.46

■5000 CALCULATED EXTRAPOLATED

25

20-3000

« VC O -2000

-1000

2000 4000 Time (s)

6000 8000

co

® IO I o'!.

» I-x:

o<D

Figure 4,20 Revised MSLB-, extrapolated heat transfer coefficient inside surface of reactor vessel downcomer wall.

4.47

18-2500

18 CALCULATED— - e x t r a p o l a t e d

CL

U -2000

12

-150010

a1200 2400 3600 4800

T im e (s)8000 7200

mCL

3n(Oo

oE3O>

Figure 4.21 Maximum sustainable overfeed, reactor vessel downcomer fluid pressure.

580 CALCULATED— - EXTRAPOLATED

-550

•500

*o520

O"

500

7200600036000 1200

«i-3a«a.Eo

3cr

«E3O>

T im e (s)

Figure 4.22 Maximum sustainable overfeed, reactor vessel downcomerfluid temperature.

4.48

Table 4.9. Turbine bypass valve failure at reactor bot standby transientsequence of events

EventTime(s)

Turbine bypass valves fail open 0MFW pump discharge pressure decreases to 765 psia 27.3HPI initiated 125.1RCPs tripped— steam generator low-level limit changed from relative to SU level taps to 240 in. relative to operating taps

24 in. level

155.1

EFW initiated in steam generator A and steam generator B because of change in low-level set pointCondensate booster pump trips on low suction pressure 163.4MFW pump trips on low suction pressure 168.5MFW train isolated from steam generators after feedwater flow decreases to zero

228.6

Core flood tank injection initiated 383.5Core flood tank injection ends 391.6Turbine bypass valves closed 600.0Pressurizer filled 900.0PORV set point reached 949.6Steam generator operating level at 240 in. 1010.2Steam generator EFW sources tripped off for last time 1030.4Steam generator A operating level at 240 in. 1070.5Steam generator A EFW sources tripped off for last time 1074.6Primary loop B cold leg suction temperature exceeds loop B leg temperature

hot 1620.5

Primary loop A cold leg suction temperature exceeds loop A leg temperature

hot 1892.2

Downcomer wall temperature reaches 265^F 4600.0Transient terminated 7200.0

4.49

CALCULATEDEXTRAPOLATED -6000

30

” IIE 20

-2000

«•X

1200 2400 3600 4800Time (s)

6000 7200

c<DO,

® 1 o 1

o Lc > a ^-Jrxia(S

X

Figure 4.23 Maximum sustainable overfeed, reactor vessel downcomer inside surface heat transfer coefficient.

4.50

20000

■2500

-2000O'w3«»S 10000 ■wa.o£— 5000O >

.-1500

-1000

-500

tna.4)U.3tntno>

oE3

O>

1000 2000 3000 4000 5000TIME (»)

6000 7000 8000

Figure 4.24 TBV failure at HSB, reactor vessel downcomer pressure.

600-600

i: 550-500

9- 500-400

450

-300400

-200350

»u3

9Q.£

3cr

9E3O>

1000 2000 3000 4000 5000TIME (s)

6000 7000 8000

Figure 4.25 TBV failure at HSB, reactor vessel downcomerfluid temperature.

4.51

psia), tlie opening set point pressure for the power-operated relief valve

(see Figure 4.24).

The uncertainty in the calculated downconer fluid teaperature, expressed

as error bars in Figure 4.2S, was assessed. This uncertainty was due

to startup valve operation, code-calculated condensation effects, and low

level limit determination method. The uncertainty was found to be minor,

and the conclusion is that the calculated temperature represents the lower

temperature limit of the uncertainty band.

4.3.1.7 Pressurizer Surge Line Small-Break Transient

The pressurizer surge line small-break transient was calculated using both

RELAP5 and T8AC (see Section 4.3.2.5). The INEL calculation is transient

55 (INEL5) in Table 4.25.

The transient was initiated by a 0 .0508-m-(2-in.) diam break in the

horizontal section of the pressurizer surge line with the reactor at full

power conditions. Operator action is assumed to trip power to the reactor

coolant pumps (RCPs) 30 s after initiation of high-pressure injection

(HPI). This scenario is similar to that discussed in Section 4.3.1.3

except that the break is larger and has been relocated from the PORV to

the surge line. Operator action to trip RCPs is assumed.

Table 4.10 gives the sequence of events for the calculation. Figures 4.27

through 4.29 suamarize the results of the calculation and extrapolation to

7200 s. Error bars indicate the uncertainty limits for this calculation.

4.52

Table 4.10 Pressnxizer surge line break transient sequence of events

TimeEvent (s)

Open break in pressurizer surge line 0.0

Reactor scrams on P versus T relationship: turbine 45.2stop valves close; heater drains to feed train begin to close; MFW pumps begin to run back

TBV open on high steam generator pressure 47.0

SRV open on high steam generator pressure 50.0

Pressurizer heaters turn off on lov-pressurizer 55.3liquid level

SRV close as steam generator pressure drops 69.0

MFW pumps trip on high pump discharge pressure 70.0

HPIS injection begins on low primary pressure 78.5

Upper head begins to void 86.0

RCP trip 30 s after HPI initiation; realign main 108.5feedwater to emergency feed headers; emergency feed begins on low steam generator level

TBV closes as steam generator pressure drops 117.0

Upper head volume completely drained of liquid; top 300.0volume of downcomer begins to void

Feed to steam generator B stopped as low liquid level 500.0limit is exceeded

Emergency feed to steam generator A stopped as low 503.0liquid level limit is exceeded

Vent valves open 554.0

Bubble forms in tubes of steam generator A; bubble 768.0starts to move to top of candy cane

Flow stagnates in loop A as bubble fills top of 815.0candy cane

Circular flow between cold legs of loop A 872.0

4.53

Table 4.10 (continued)

EventTime(s)

Bubble formed in tubes of steam generator B; bubble 892.0starts to move to top of candy cane

Flow stagnates in loop B as bubble fills top of 1020.0candy cane

Bubble in top volume of downcomer collapses 1383.0

Partial collapse of bubble in upper head: liquid drawn 1400.0up is heated and vaporized by hot metal; primary pressure momentarily raises

Bubble in upper head collapses, volume refills with 1488.0liquid; large flows throughout primary system as liquid moves toward upper head

Core flood tank begins injection on low primary pressure 2215.0

Circular flow between cold legs of loop B starts 2378.0

Circular flow between cold legs of loop B reverses 2443.0direction

Pressurizer begins to refill with liquid 5064.0

LPIS injection begins on low primary pressure 5124.0

Calculation terminated 6200.0

4.54

30-5000

-4000u. 20

-3000

-2000

-1000Ui

2000 3000 5000 SOOO 7000 SOOO1000 40000

zUi

CJti. tZ"Ui •O I

Q£ I ui ^ Li- JZ

Q1 CQ t—

<UJ

TIME (s)

Figure 4.26 TBV failure at HSB, reactor vessel inside surface heat transfer coefficient.

4.55

oa.2

ocz>tninU ioca.U i2Z>_ (o>

20 CALCULATED EXTRAPOLATED -2500

15 -2000

-150010

-1000

5-500

01000 2000 3000 4000 5000 SOOO 7000 8000

Time (s)0

Figure 4.27 Pressurizer surge line bxeak, extrapolated RV downcomer pressure.

-600 CALCULATED EXTRAPOLATED

b 550-500

-400

450

-300

400

-200350

ou3

001£9

3O'

9E3O>

1000 2000 3000 4000 SOOOTime (s)

6000 7000 8000

Figure 4.28 Pressurizer surge line break, extrapolated RV downcomerfluid temperature.

4.56

As shovn in Figure 4.28, the BiniauB downcoBer fluid teaperature calculated

vas 380 K (22S°F) and occurred at the end of the calculation, 6200 s. By

extrapolating trends evident near the end of the calculation, the downcoaer

teaperature would drop to 355 K (180*^F) by 7200 s. The ainiaua cold leg

teaperature calculated (adjacent to the reactor vessel) was 333 K (140*^F),

which occurred at 1130 s when the priaary systea pressure was 6.1 MPa (740

psia). At the end of the calculation, the priaary systea pressure was at

the LPI shutoff head, 1.48 MPa (214 psia). Since LPI injection was holding

priaary pressure at this point, it would be expected to stay very close

to that pressure through 7200 s.

4.3 .1.8 Reactor Coolant Puap Suction Saall-Break Transient

The reactor coolant puap suction saall-breah sequence is transient 58

(INEL8) in Table 4.25.

The transient is initiated froa full power steady state (noainal teaperature

and pressure). The pressurizer heaters and spray operate as designed. The

transient is begun by a break downstreaa of a valve in the letdown line

connected to the bottoa of the A-1 puap suction leg.

The letdown line is 0.0635 a (2-1/2 in) in diaaeter. The break was assuaed

to occur downstreaa of a aotor valve that could be isolated. Closure

of this block valve was si>ecified to occur only after core flood tank

injection. The distance froa the priaary piping to the valve in the line

was approxiaately 15.24 a (50 ft). The valve throat was assuaed to have

the saae inside diaaeter as the pipe.

4.57

Folloving reactor scraa, the decay heat ia assumed to be the ANS standard.

The tnrbine stop valves close, and it is assnmed the integrated control

system operates as designed. After the core flood tanks empty, the break

is isolated and high-pressnre injection flow is throttled when 28 K (50°F)

snbcooling is attained, bnt only if the primary system has repressnrized

to the power-operated relief valve (PORV) set point.

Table 4.11 gives the sequence of events for the calculation. Figures

4.30 through 4.32 summarize the calculation and extrapolation to 7200 s for

downcomer temperature and pressure. Error bars in the figures identify the

uncertainty limits. Calculated oscillations of cold leg flow contributed

to the uncertainty and caused early termination of the calculation.

For the reactor coolant pump suction break sequence, the downcomer fluid

temperature was 470 E (38d^F) at the end of the calculation (4900 s). The

transient was extrapolated to 7200 s (2 h), and at that time, the downcomer

temperature was estimated to be 446 K (343^F) at a pressure of 5.1 NPa

(740 psia).

The major uncertainty in the calculation is related to the existence

of loop flow oscillations. Had these oscillations not been present in

the calculation, the downcomer fluid temperature at 2 h would have been

estiaiated to be 390 K (242°F) .

The sequence requirement to isolate the break (by closing the motor block

valve in the letdown) was not encountered because core flood tank injection

did not occur. Had this isolation occurred, the subsequent maximum primary

4.58

Table 4.11 Pnaip suction bxeak transient sequence of events

EventTime(s)

Break in loop A-1 pump suction leg occurs 0.0

Reactor scrams on (P, T) relationship; turbine 48.60stop valves close: heater drains begin to close; turbine bypass and steam generator secondary safety valves operate as designed

Pressurizer heaters latched off due to low level in 60.92pressurizer

Main feedwater pumps trip on high discharge pressure 75.88

Primary pressure dropped below high-pressure injection 94.32set point and injection began

Upper head began to void 100.0

Reactor coolant pumps trip 30 s after high pressure 124.0injection initiation; main feedwater flow realigned to the EFW headers

Motor- and turbine-driven emergency feedwater systems 124.36initiated because of low level limit in the steam generator secondaries

Steam generator A and B turbine bypass valves close 135.0

Upper head completely voided 424.0

Steam generator B secondary pressure dropped below the 500.0booster pump head in the main feedline and main feed­water commenced to flow into A generator secondary, via the startup valves and crossover

Steam generator A secondary pressure dropped below the 545.0booster pump head in the main feedline and main feedwater commenced to flow into A generator secondary via the startup valves and crossover

Steam generator B emergency feedwater flow stopped because 573.71of liquid level above the low-level signal

4.59

Table 4.11 (continued)

EventTiine(s)

High level U n i t signal in steam generator B reached due 596.97to flow through startup valves

Loop natural circulation established 600.0

Steam generator A emergency feedwater flow stopped due to 631.90liquid level above the low-level signal

High-pressure injection volumetric flow rate exceeds the 650.0break volumetric flow rate and primary system depressurization essentially stopped

High level limit signal in steam generator A reached due 660.80to flow through startup valve

ICS ramped B startup valve closed, isolating steam generator 675.0 B secondary

Vent valve flow commenced 680.0

Level in pressurizer began to recover; void in upper head 700.0began to collapse

ICS ramped A startup valve closed, isolating steam generator 731.0 A secondary

Primary mass lost out the break regained by high-pressure 900.0injection mass

Upper head became liquid solid: primary system began to 1350.0repressurize

Natural circulation lost in loop B 2000.0

Primary pressure turned over; volumetric break flow 2200.0exceeded volumetric HPI flow

Flow in loop B reversed 2380.0

Flow reversal in loop B recovered 2800.0

Series of flow reversals in loop B mixed cold BPI water 2800.0with warm primary liquid in the loop B cold legs to

4900.0

4.60

Table 4.11 (continued)

TimeEvent (s)

Transient terminated pattern established in transient to 4900.0enable extrapolation of downcomer pressure and temperature to 7200 s; downcomer pressure and temperature at termination of transient were 6.0 MPa (870 psia) and 470 K (386*^F), respectively

Extrapolated downcomer pressure and fluid temperature are 7200.05.1 MPa (740 psia) and 446 K (343°F) respectively

4 . 6 1

I

<Rc-a

30 -5000• CALCULATED - EXTRAPOLATED

20-3000

-200010

-1000

0 7000 3000600050002000 3000 40000 1000

ca>

® I° J

a ^ m

a9

X

Figure 4.29 Pressurizer surge line break, extrapolated RVdowncomer inside surface heat transfer coefficient.

4.62

600-600

• DOWNCOMER - EXTRAPOLATED

-500

« 500 Q.

-300CT400

-200

-1003000 1000 30002000 4000 5000 6000 7000 8000

o>k.3

9aEo

3or

(0£3O>

Time (s)

Figure 4.30 Pump suction Loreak, reactor vessel downcomer fluid temperature.

20CALCULATEDEXTRAPOLATED

-2500CL

LJ□C -2000toUIQCQ.

-1500Ui

-1000

SOOO7000SOOO 60003000 40000 1000 2000

0)Ol

3nn9

9E3O>

Time (s)Figure 4.31 Pump suction tireak, reactor vessel downcomer fluid

pressure.

4.63

pressure vould have bees ~16.99 MPa (2465 psia)< tbe opening pressure set

point of tbe power-operated relief valve.

4.3 .1.9 Steam Generator Tube Rupture Transient

Tbe steam generator tube rupture sequence is transient 59 (INEL9) in Table

4.25. Tbe transient is initiated from full power steady state conditions

(nominal temperature and pressure). Tbe pressurizer beaters and spray

operate as designed. Tbe transient begins witb a rupture of a single steam

generator tube (double-ended break) in tbe A loop steam generator. It is

assumed tbe ICS operates as designed. Tbe reactor scrams and tbe turbine

stop valves close. Emergency feedwater starts on low-level limit signal

and secondary safety relief and turbine bypass valves operate as designed.

Table 4.12 gives tbe sequence of events for tbe calculation. Figures 4.33

tbrougb 4.35 summarize tbe calculation and extrapolation to 7200 s. At tbe

termination of tbe transient, tbe primary system pressure was oscillating

around tbe PORV set point pressure of 17.0 MPa (2465 psia). Tbe reactor

vessel downcomer liquid temperature, wbicb is of PIS concern, was at 517

K (470°F) and increasing slightly. As sbown in Figures 4.33 and 4.34,

tbe extrapolated values of pressure and temperature to 7200 s are 17.0 MPa

(2465 psia) and 544 K (520°F) respectively. Tbe lowest vessel downcomer

liquid temperature was 505 K (450°F), wbicb occurred at 1700 s.

4.3.2 TRAC Calculations

Tbe sequences simulated by tbe TRAC model are listed in Table 4.2. Detailed

discussion of tbe transients and tbe results are available in Reference

4.2. A summary of all transients discussed bere and in Sections 4.3.1

4.64

Table 4.12 Steam generator tube rupture transient sequence of events

EventTime(s)

Steam generator tube rupture in steam generator A occurs: ICS adjusts MFW valves to compensate for perturbation in steam generator A secondary system

Reactor scram (P/ T) relationship turbine trip, turbine stop valve closes, heater drains close over 5-s period;ICS runs back MFW pumps and MFW valves

Pressurizer heaters come on because of low primary pressure

Pressurizer level drops belov 220 in. and makeup flow increases

Pressurizer levels drops below 127.6 in. the pressurizer heater power

cutting off

Main feedwater pumps trip on high discharge pressure because of ICS running back the startup valves

Primary pressure increased because of reduction in primary to secondary heat transfer

Level in steam generator B secondary oscillates around low level set point, allowing periodic flow of emergency feedwater into secondary system: periodic flow of emer­gency feedwater enhances primary to secondary heat trans­fer, and primary pressure turns over

Primary pressure dropped below HPI set point, HPI flow initiated, makeup and letdown flow stopped

RCPs trip 30 s after HPI initiation: steam generator low-level set point increased and motor- and turbine- driven emergency feedwater system turned on; increased primary to secondary heat transfer enhances primary fluid cooldown

0.0

319.2

321.6

325.4

336.3

349.0

650.0

775.0

942.4

972.4

Liquid in the main feedline commenced to flow into steam generator B through the startup valve and crossover due to the secondary pressure dropping below the booster pump head

1280.0

Liquid in the main feedline commenced to flow into steam generator A through the startup valve and crossover because the secondary pressure dropped below the booster pump head

1300.0

4.65

Table 4.12 (continued)

EventTime(s)

Liquid level in steam generator A rose above the level limit 1396.6set point and EFW into the secondary uas terminated

Liquid level in steam generator B rose above the low level 1415.5limit set point and EFW into the secondary was terminated

Liquid level in steam generator A rose above the high-level 1426.0limit set point and ICS closed the startup valve, isolating steam generator A

Liquid level in steam generator B rose above the high-level 1437.6limit set point and ICS closed the startup valve, isolating steam generator B

Steam generators become heat sources; primary temperatures 1600.0begin to increase

Primary pressure reached PORV set point; the valves 2200.0oscillate around the set point, maintaining primarypressure

Pressurizer becomes liquid-solid 2450.0

Transient terminated; vessel downcomer liquid temperature 2800.0at 517 E (471°F) and increasing; pressure at the PORV set point

4.66

c

« > •** ><2C '«w'ou

ooX

30 p

t

20 H§Y

10 -

I — ' ■CALCULATED

•EXTRAPOLATED

2000J ______________________ L

60004000 Time (s)

5000

-4000

-3000

-2000

-1000

SOOO

o i Z ^<^o UJ Io j

q: IUI ^ u. ^ to Z 3^ m

Figure 4.32 Pump suction hreak, reactor vessel downcomer inside surface heat transfer coefficient.

4.67

1 - 2 6 0 018

-24.00

-2200UJoc2D</)CO -2000U i

CALCULATED EXTRAPOLATED

O>-tsoo

8000700060003000 4000 5000Time (s)

20001000

<oQ.

3nV)9k.Q.OE3O>

Figure 4.33 SG tube rupture, extrapolated RV downcomer fluid pressure.

580 CALCULATED EXTRAPOLATED

-550a9Q.E9 540

-5003CT

5209E3O>

5000 1000 30002000 4000 5000 6000 7000 8000

Figure 4.34

Time (s)

SG tube rupture, extrapolated RV downcomer fluidtemperature.

9u3Ok.oa.Ee

3CT

9E_3O>

4.68

co

co

o«X

30

10 -

CALCULATEDEXTRAPOLATED

-5000

1800 3600Ti me (s)

5A00 7200

zUI

O n3000 O C

q: I

2000

woo <utX

Figure 4.35 SG tube rupture, extrapolated RV downcomer inside surface heat transfer coefficient.

4.69

and 4.5 is provided in Section 4.6 and Table 4.25. The Oconee-3 feedvater

transient was a benchaark case of no direct iaportance to this study and

is oaiitted here. Reference 4.2 contains a discussion of that calculation.

4.3 .2.1 Main Steaai Line Break

The LANL aiain steaa line break (MSLR) base case is the TRAC model

calculation (Section 4.3.1.4). Three parametric cases (cases 2, 3 and

4) reflecting different feedvater system responses were also performed.

The MS LB base case and parametric cases 2 and 3 appear in Table 4.25 as

transients 35 (LANLl), 37 (LANL3)< and 38 (LANL4) respectively. Parametric

case 4 was provided too late for inclusion in all phases of this study, but

would significantly impact the extrapolation of steam line break sequences

(see Appendix C, Section C.3.) The present discussion centers on the MS LB

base case calculation.

The transient is initiated by a double ended 34-in.-diam break in Steam

Line A. In the unaffected steamline (SG B) the TSV was closed, and the

TBV system operated as designed. All of the other systems also operated

as designed except for the parametric cases. The significant features

and initial conditions for the MS IB calculations were: (1). Full reactor

power. (2). Nominal temperatures and pressures in primary/secondary.

(3). Decay heat - 1.0 times ANS standard. (4). Reactor and turbine trips

coincident with ISLB. (5). Operator fails to isolate feedvater to both

SGs until 600 s. (6). Operator restores unaffected SG (SG B) at 900 s.

(7). RCPs restarted after 42 K subcooling reached. (8) . HPI throttled

to maintain 42 +12.5 K snbcooling.

A. 70

Cas« 2 v « t id o B t io a l t o th e base case excep t th e EFf system d id n o t a c tu a te

as d e s ig n ed because o f a m odeling e x ro r in tb e in p u t deck . In case 3 , in

a d d i t i o n t o the EFW s y s te m 's f a i l i n g to a c tu a te as d e s ig n ed , th e RCPs never

r e s t a r t e d a f t e r the su b co o lin g margin was reached because o f inpu t deck

e r r o r s . In case A, th e MFW pump was t r i p p e d a t 0 .5 s and th e subcoo ling

m on ito r f o r r e s t a r t i n g th e RCPs was moved from the h o t le g to the top

o f the c o re , th e p ro p e r l o c a t i o n . A lthough th e se p a ra m e tr ic ca se s were

n o t s p e c i f i e d , th ey a re s t i l l u s e f u l c a l c u l a t i o n s because they g ive o th e r

p o s s i b l e s c e n a r io s t h a t p o s s i b ly cou ld occur du r in g a NSLB t r a n s i e n t and

a r e u s e f u l f o r e x t r a p o l a t i o n a c t i v i t i e s .

T ab le 4 .13 g iv e s th e sequence o f e v en ts f o r the base case c a l c u l a t i o n .

F ig u re s 4 .3 6 th ro u g h 4 .3 8 summarize the r e s u l t s o f th e base case

c a l c u l a t i o n . The main fo r c in g f u n c t io n f o r the o v e rco o l in g was a s p e c i f i e d

d e la y o f th e o p e r a to r in i s o l a t i n g the a f f e c t e d steam g e n e ra to r coupled w ith

a d e la y in t h r o t t l i n g th e HPI f l o u . The base case ana lyzed had a l l p la n t

p r o t e c t i o n and c o n t r o l system s o p e ra te as d e s ig n e d . The minimum dovncomer

f l u i d te m p e ra tu re c a l c u l a t e d f o r the base case was 405 K. R e p r e s s u r iz a t io n

o f the p rim ary system to th e PORV s e t p o in t was c a l c u l a t e d f o r the base

case fo llo w in g an i n i t i a l d e p r e s s u r i z a t i o n to 3 .5 MPa.

In th e f i r s t two p a ra m e tr ic c a se s ( c a s e s 2 and 3 ) , in p u t and modeling

e r r o r s p re v e n te d th e EFW system from o p e ra t in g as d e s ig n ed . Case 3

had an a d d i t i o n a l in p u t e r r o r t h a t p re v e n te d th e RCPs from r e s t a r t i n g

once adequa te su b co o lin g was ach iev ed . For th e se p a ra m e tr ic c a s e s , th e

downcomer f l u i d te m p e ra tu re s were c o n s id e ra b ly h ig h e r than th e base case

4 . 7 1

Table 4 .1 3 Main s te a m lin e b re a k (base ca se ) sequence o f ev en ts

Event Time(s)

MSLB loop A s t e a a l i n e 0 .0

T urb ine and r e a c t o r t r i p : TSV loop B c lo s e s 0 .5

TBV loop B opens ( s e t p o in t 7 .063 MPa) 5 .0

HPI i n i t i a t i o n ( s e t p o in t 10 .44 MPa) 21 .2

SG A lo w - le v e l l i m i t r e a c h e d ; loop A SG EFf flow i n i t i a t e d 29 .4

TBV loop B c lo s e s 39 .9

NFV pump t r i p on low s u c t io n p r e s s u r e 4 7 .8

SG B lo w - le v e l l i m i t reach ed : loop B EFf flow i n i t i a t e d 48 .8

SCPs t r i p (30 s a f t e r HPI i n i t i a t i o n ) 51.2

Condensate b o o s t e r pump t r i p (low s u c t io n p r e s s u r e ) 53 .9

SG B l e v e l a t 50%: loop B EFf v a lv e c lo se d 346.7

RCPs (A l, B l) r e s t a r t (42 E subcoo ling ) 526.0

Loop A, B accum ula to r s e t p o in t s reached ( s e t p o in t 4 .17 MPa) 530.9

Loop k , B acc u m u la to rs o f f 537.9

SG A, B i s o l a t e d EFf pump and h o tw e l l pump t r i p p e d o f f 600.0

SG B r e s to r e d 900.0

PORV s e t p o in t reached ( s e t p o in t 1 6 .9 MPa) PORV opens and c lo s e s f o r rem ainder o f c a l c u l a t i o n 4678-7200.0

TBV loop B opens ( s e t p o in t 7 .063 MPa) TBV opens and c lo s e s f o r rem a inder o f c a l c u l a t i o n t o m a in ta in s e t p o i n t p r e s s u r e 5462-7200.0

SG B le v e l d rops below 50% o p e ra t in g range EFf i n i t i a t e d EFf pump o n / o f f f o r rem ainder of c a l c u l a t i o n to m a in ta in l e v e l a t 50% 6121-7200.0

C a lc u la t io n te rm in a te d 7200.0

4 . 7 2

•0-2900

«0-2290

MO- -2000

1790no

-000

■0 -

-1000

• 0 --790

-900

•0007000•0001000 90000 2000 3000 4000

T»C(»)F ig u re 4 .3 6 P r e s s u r iz e r p r e s s u r e , main steam l i n e break — b a se c a s e .

940

9«0-

TVIZ820-

900

490-

400«00 2000 9000 4000 9000 *000 7000

m c (s )

F ig u re 4 .3 7 Downcomer l iq u id te m p e r a tu r e s , main steam l i n e break - b a se c a s e .

4.73

10000-

14000-z

12000-t -z u— 20000

(ZCuu aooo-4 8 zU. 6000-u,V3z^ 40004

■

2 X

MOO aoQo aooo 40oo TIME (a)

•000 7000

F ig u re 4 .3 8 H e a t - t r a n s f e r c o e f f i c i e n t s , m ain s team l i n e b r e a k b a s e c a s e .

4 . 7 4

(c a se 2 475 K; case 3 450 K ); th u s g r e a t e r m argins a g a in s t PTS were

c a l c u l a t e d .

In th e l a s t p a ra m e tr ic case (ca se 4 ) , o th e r changes were made to the model

t o r e f l e c t in fo rm a t io n p ro v id e d by Duke Power a f t e r the base case was ru n .

I n t h i s c a s e , th e su b co o lin g m on ito r was c o r r e c te d and the MFW pump was

t r i p p e d a t 0 .5 s . T h is case was run to 2100 s . and the minimum downcomer

f l u i d te m p e ra tu re was 420 K. None of th e changes in c o rp o ra te d in to case

4 r e s u l t e d in s i g n i f i c a n t d i f f e r e n c e s from the base c a s e .

4 .3 .2 .2 PORV LOCA T r a n s ie n t

The PORV LOCA sequence c a l c u l a t e d by LANL i s t r a n s i e n t 39 (LANL5) in Table

4 .2 5 . T h is case i s th e same as th e INEL PORV sm all ho t leg b re a k , excep t

f o r th e t r i p p i n g o f th e RCPs by th e o p e r a to r in th e LANL c a se .

The PORV was assumed to open a t t r a n s i e n t i n i t i a t i o n and rem ain s tu c k open

f o r th e rem ainder o f th e a c c id e n t sequence . T h is even t was fo llow ed by

th e r e a c t o r and tu r b in e t r i p s from f u l l power. I n a d d i t i o n to the PORV

f a i l u r e , th e ICS f a i l e d to run back th e main fe e d w a te r . As a r e s u l t ,

th e steam g e n e ra to r s c o n t in u e d to f i l l u n t i l the NFV pumps were t r i p p e d on

h ig h SG l e v e l s i g n a l . To ac h ie v e t h i s o v e r f i l l , th e h igh d is c h a rg e and low

s u c t i o n p r e s s u r e t r i p s o f th e NFV pumps were o v e r r id d e n . The PORV f a i l u r e ,

NFV t r i p o v e r r id e , and th e ICS f a i l u r e were th e on ly assumed s y s te m - re la te d

f a i l u r e s . The RCPs t r i p p e d 30 s a f t e r HPI i n i t i a t i o n , and t h i s was th e

o n ly s p e c i f i e d o p e r a to r a c t i o n .

Table 4 .1 4 g iv e s th e sequence of e v e n ts f o r the c a l c u l a t i o n . F ig u re s 4 .39

4 . 7 5

Table 4 .1 4 PORV LOCA Sequence o f Events

Event T ime(s)

PORV opens 0 .0

T urb ine and r e a c t o r t r i p 0 .5

T urb ine s to p v a lv e s c lo s e 0 .5

S eco n d a ry -s id e b e a t e r and b e a t e r d r a in t r i p 1 .1

Condenser feed from tu r b i n e t r i p 1 .6

TBV-loop A opens f o r f i r s t time 4 .4

TBV-loop B opens f o r f i r s t time 4 .7

C o n d e n s a te -b o o s te r pump t r i p s on low s u c t i o n p r e s s u r e 1 1 .0

TBV-loops A and B o p e n /c lo s e 16.2

HPI a c t u a t i o n on low p rim ary system p r e s s u r e 70.3

TBV-loops A and B o p e n /c lo se 71 .1

RCPs t r i p 30 s a f t e r HPI a c t u a t i o n 100.3

MFW r e a l ig n e d t o SG upper h ead e rs 100.3

MFCV o v e r r id e t r i p 100.3

MFW pump t r i p on b ig b SG le v e l ( lo o p A) 250.3

TBV-loop B opens f o r l a s t t isw 330 .0

Minimum p rim ary p r e s s u r e ( 7 . 2 MPa) a t t a i n e d 550.0

P r e s s u r i z e r v a t e r - s o l i d 600 .0

Maximum p rim ary r e p r e s s u r i z a t i o n ( 11 .5 MPa) 850 .0

End o f c a l c u l a t i o n 1000.0

4 . 7 6

thTOOgb 4 .41 s u a n a r iz e th e r e s u l t s o f th e c a l c u l a t i o n and e x t r a p o l a t i o n to

7200 s .

TRAC c a l c u l a t e d a minimua v e s s e l dovncomer l i q u id te m p era tu re of 528 K

between 600 s and 700 s i n t o th e t r a n s i e n t . The prim ary system was

c a l c u l a t e d to r e p r e s s u r i z e to 11 .5 MPa a f t e r 800 s . A f te r re c o v e r in g

b r i e f l y betw een 800 s and 1000 s , th e downcomer tem pera tu re was e x t r a p o la t e d

to 527 (489°F) a t 7200 s . P r e s s u r e remained a t 11 .5 MPa to the end of

the t r a n s i e n t .

4 . 3 .2 . 3 F a i l u r e of Two T urb ine Bypass V alves a t F u l l Power

The LANL c a l c u l a t i o n s o f two tu r b i n e bypass v a lve (TBV) f a i l u r e s a t f u l l

power in c lu d e a base case (5A) and two p a ra m e tr ic cases (5B and 5 0 . These

sequences appea r in Table 4 .2 5 as t r a n s i e n t s 40 (LANL6), 41 (LANL7), and

42 (LANL8).

The s i g n i f i c a n t f e a t u r e s o f th e 2-TBV f a i l u r e t r a n s i e n t base case (5A) a r e :

( 1 ) . R eac to r and tu r b in e t r i p s cause th e IBVs to open.

( 2 ) . F a i l u r e o f one bank o f TBVs t o c lo s e causes a sec o n d a ry -s id e

d e p r e s s u r i z a t i o n th ro u g h th e a f f e c t e d loop .

( 3 ) . The ICS f a i l s to runback to th e a f f e c t e d steam g e n e ra to r .

( 4 ) . F a i l u r e o f th e SG l i q u i d l e v e l c o n t r o l in the a f f e c t e d loop

fo l lo w s i n i t i a t i o n o f EFW.

( 5 ) . The o p e r a to r does n o t r e s t a r t the RCPs.

( 6 ) . The o p e r a to r does n o t t h r o t t l e the HPI.

( 7 ) . The o p e r a to r does n o t i s o l a t e / c o n t r o l feed w ate r .

Two p a ra m e tr ic ca se s were a l s o c a l c u l a t e d . The steam g e n e ra to r l i q u i d -

l e v e l c o n t r o l in the a f f e c t e d loop o p e r a t e s c o r r e c t l y in case 1 (5 B ) .

4 .7 7

EXTRAPOLATED

•00

•00070000 noo iooo •000aooo 4000

71M£(*)

F ig u re 4 , 3 9 PORV LOCA e x tr a p o la te d system p r e s s u r e .

•70

-sso••0EXTRAPOLATED

•60

-SM636-

-600

926-

120«XW 2000 9000 9000 7000•000

Q5s

F ig u re 4 .4 0 PORV LOCA e x tr a p o la te d downcomer l iq u id tem p era tu re .

4. 78

IflOOO

^ MOOO

^ 12000EXTRAPOLATED

BOOO

6000

4000

2000

7000fiOOO1000 aoooTIM£ (s)

^»41 PORV LOCA e x t r a p o l a t e d downconier h e a t —t r a n s f e r c o e f f i c i e n t .

4 . 7 9

The s t e a a g e n e ra to r l i q u i d l e v e l c o n t r o l a l s o o p e r a te s c o r r e c t l y in case

2 (SC), and o p e r a to r a c t io n s to r e s t a r t th e RCPs and t h r o t t l e th e HPI

a re p e rm i t t e d i f the p r im ary system s n b co o lin g -m o n ito r t r i p p o in t s a re

exceeded .

Table 4 .1 5 g iv e s th e sequence of e v en ts f o r the base c a s e . The p a ra m e tr ic

c a s e s fo llo w t h i s ex a c t sequence to the s t a r t i n g o f the EFW pump a t 209

s . In p a ra m e tr ic case 1 , th e c lo s u re o f th e EFW c o n t r o l v a lv e on SGA (290

s) speeds th e c lo s u r e o f the EFW v a lve to SGB (460 s) and opening o f th e

PORV (975 s ) . In p a ra m e tr ic case 2 , th e c lo s u r e of the EFW v a lve to SGA

(290 s) b r in g s about RCP r e s t a r t a t 383 s , c lo s u r e of th e EFW v a lv e to

SGB (395 s ) , and t h r o t t l i n g o f HPI (485 s ) .

F ig u re 4 .42 g iv e s th e c a l c u l a t e d and e x t r a p o la t e d p r e s s u r e s f o r th e b ase

and p a ra m e tr ic c a s e s . F ig u re s 4 .43 th ro u g h 4 .4 5 g iv e s th e c a l c u l a t e d and

e x t r a p o la t e d te m p e ra tu re s f o r the base and p a ra m e tr ic c a s e s . F ig u re 4 .46

g iv e s the c a l c u l a t e d and e x t r a p o la t e d h e a t t r a n s f e r c o e f f i c i e n t f o r th e

base case and p a r a m e tr i c Case 1 . A f te r r e s t a r t o f 1 RCP/loop in p a ra m e tr ic2

case 2 , a f i n a l h e a t t r a n s f e r c o e f f i c i e n t of 7500 w/m K i s o b ta in e d .

The f a i l u r e to i s o l a t e main and emergency feed w a te r to th e a f f e c t e d steam

g e n e r a to r r e s u l t e d in v e ry low te m p e ra tu re s f o r a l l th r e e cases a t 7200

s . The base case was e x t r a p o la t e d to 365 K. P a ra m e tr ic cases 1 and 2

were e x t r a p o la t e d to 440 K and 430 K r e s p e c t i v e l y .

4 . 3 . 2 . 4 F a i l u r e o f Four T urb ine Bypass V alves a t F u l l Power

The LANL c a l c u l a t i o n s o f fo u r tu r b in e bypass v a lv e s (TBV) a t f u l l power,

l i k e the two-TBV f a i l u r e c a s e s (S e c t io n 4 . 3 . 2 . 3 ) , a l s o in c lu d e a b ase case

4 . 8 0

Table 4 .1 5 2-IBV f a i l u r e f u l l power sequence o f ewents (base case)

Event Time(s)

T urb ine and r e a c t o r t r i p 0 .5

T urb ine s to p v a lv e s c lo se 0 .5

IBV loop A opens ( f a i l s t o r e s e a t t h e r e a f t e r ) 4 .1

TBV loop B opens 4.3

NFV pump t r i p on h ig h SG A l i q u i d l e v e l 60.7

HPI s t a r t e d fo l lo w in g t r i p on low p r e s s u r e 153.1

RCPs t r i p on 3 0 -s d e la y a f t e r HPI a c t u a t i o n 183.0

Feedw ater r e a l ig n m e n t 183.0

Main flow c o n t r o l v a lv e s o v e r r id in g t r i p s 183.0

EFW flow i n i t i a t e d 209.1

Loop-B EFW v a lv e shu t on h ig h SG l i q u i d l e v e l 460.8

PORV opens 1036.7

4 . 8 1

lao-2535

!S6 2235

-1835f 130.

1*0 ltd) BASE(dash) PARAMETRIC 1• chndah) PARAMETRIC 2

106

66 --735

90 4350 1000 2000 70003000 60004000 5000

F ig u r e 4 .4 2 P r e s s u r i z e r p r e s s u r e h i s t o r i e s f o r 2 TBV f a i l u r e s ( c a s e 5A -base ; c a s e 5 B - p a r a m e t r i c ; c a s e S C -p a ra ­m e t r i c 2) .

4 . 8 2

• THETA « 1• THETA * 2 •THETA - 3 ■ THETA • 4 •THETA « 5 •THETA - e

S40

^ 510

ua 480

^ 450-

u420-

248.3360-

188.33006000 700050002000 3000 400010000

P ig u re 4 . 4 3 Downcomer l iq u id tem p eratu res fo r c a se 5A.

500 684J3

- 539.3

•THETA - 1 • THETA ■ 2 •THETA - 3

THETA « 4 •THETA - 5 •THETA - 6

U 480

- 359.3

F ig u re 4 . 4 4 Downcomer l iq u id tem p eratu res fo r c a se 5B.

4. 83

• THETA• THETA •THETA •THEEA -THETA •THETA

870

545

520

uH 470

445-

42070000 1000 2000 3000 5000 60004000

F i g u r e 4 ,4 5 Downcomer l i q u i d t e m p e r a t u r e s f o r c a s e 5C.

4 . 8 4

12000

u i a rn o 8U 6000 fa.

g 4000

8000-X

m o TOGOaooo aooo aooo4000TIME (•)

F ig u r e 4 ,4 6 H e a t - t r a n s f e r c o e f f i c i e n t s f o r c a s e 5A.

4 . 8 5

(6A) and tv o p a r a a e t r i o c a se s (6B and 6 0 . These sequences ap p ea r in Table

4 .2 5 as t r a n s i e n t s 43 (LANL9). 44 (LANLIO), and 45 (LANUl) r e s p e c t i v e l y .

The base and p a r a a e t r i c case d e s c r i p t i o n s a re th e saae as f o r th e tvo-TBV

f a i l u r e c a se s ex cep t t h a t a l l fo u r TBVs ( tv o on each s t e a a l i n e ) f a i l to

r e s e a t a f t e r open ing .

T ab le 4 .1 6 g iv e s th e sequence o f e v e n ts f o r the base c a s e . P a r a a e t r i c

case 1 b e h a v io r d i f f e r s f r o a th e b ase case on ly in th e p ro p e r o p e r a t io n

o f th e EFV c o n t r o l s . P a r a a e t r i c case 2 i s a l s o s i a i l a r to th e b ase case

u n t i l th e HPI i s t h r o t t l e d (421 s) and 1 RCP/loop i s r e s t a r t e d (517 s ) .

The in c re a s e d c o o l in g due to RCP o p e r a t io n red u ces p r i a a r y p r e s s u r e so t h a t

a c c u a u la to r i n j e c t i o n occu rs a t 566 s . F ig u re 4 .47 g iv e s th e c a l c u la te d

and e x t r a p o la t e d p r e s s u r e s f o r th e base and p a r a a e t r i c c a s e s . F ig u re s

4 .4 8 th ro u g h 4 .5 0 l ik e w is e g ive c a l c u l a t e d and e x t r a p o la t e d t e a p e r a t u r e s .

F ig u re 4 .5 1 g iv e s th e h e a t t r a n s f e r c o e f f i c i e n t f o r the b ase case and

p a r a a e t r i c c a se 1 . A f te r r e s t a r t o f th e RCPs, th e h e a t t r a n s f e r c o e f f i c i e n t2

f o r p a r a a e t r i c case 2 a s su a e s a f i n a l v a lu e of 7500 v / a K. As in the

tvo-TBV f a i l u r e c a s e , th e f a i l u r e to i s o l a t e main and eae rgency feed w ate r

t o b o th s t e a a g e n e ra to r s r e s u l t e d in v e ry low t e a p e r a t u r e s . M iniaua

t e a p e r a t u r e s o f 350 K, 465 E, and 350 K r e s p e c t i v e l y were e x t r a p o la t e d f o r

th e base and p a r a a e t r i c c a s e s .

4 .3 .2 .5 Small Break LOCA Two-In. Hot Leg Break

The 2 - i n . - d i a a ho t le g b re a k LOCA c a l c u l a t e d by LANL a o d e l s th e saae

c o n d i t io n s as th e INEL p r e s s u r i z e r surge l i n e sm all ( 2 - i n . - d i a a ) b re a k

t r a n s i e n t . The LANL c a l c u l a t i o n i s t r a n s i e n t 47 (LANL 13) in T ab le 4 .2 5 .

4 . 8 6

Table 4 .1 6 4-TBV f a i l u r e f n l l - p o w e r sequence o f e v en ts (base case)

EventTime

(s )

T urb ine and r e a c t o r t r i p 0 .5

T urb ine s to p v a lv e s c lo s e 0 .5

Loop A TBV opens ( f a i l s t o r e s e a t t h e r e a f t e r ) 4 .1

Loop B TBV opens ( f a i l s t o r e s e a t t h e r e a f t e r ) 4 .3

HPI b e g in s fo l lo w in g t r i p on low sy s te n p r e s s u r e 87.5

MFV pump t r i p o f f fo l lo w in g h ig h SG B l i q u i d l e v e l 91.2

RCPs t r i p on 3 0 -s d e la y a f t e r HPI a c t u a t i o n 117.4

F eedw ater re a l ig n m e n t t r i p 117.4

Main flow c o n t r o l v a lv e s t r i p 117.4

l^ e rg e n c y fe ed w a te r t r i p 117.4

PORV opens 1175.7

4 . 8 7

sao2535

156--2185

8 -1B35[aoUd) BASEdash) PARAyiTRIC 1chndsh) PARAMmiC Z

106 -1485

ao- -1135 C-

-785

ao 435700060001000 2000 50003000 4000

F ig u r e 4 .4 7 P r e s s u r i z e r p r e s s u r e h i s t o r i e s f o r 4 TBV f a i l u r e s ( c a s e 6 A -b ase ; c a s e 6 B -p a ra m e t i r c 1; c a s e 6 C -p a ra - m e t r i c 2 ) .

4 . 8 8

500THETA « 1 THETA - 2 THETA - 3 THETA - 4 THETA « 6 THETA - 6 4323L

U 43}

0 1000 2000 9000 4000 5000 0000 TVOO

F igu re 4 . 4 8 Downcomer l iq u id tem p eratu res fo r c a se 6A.

500-

500-

y 540-

U3ee

<0£UCL

520-

500-

400-

•THETA - 1 •THETA » 2 •THETA - 3 ■THETA - 4 •THETA « 5 •THET4 - 6

400-

-5 7 a3

-5403

s o a s tuD

4 7 3 3 ^ceuCL2

4 3 a3 S

-4003

1000 2000 3000 4000 5000 6000 7000

F ig u re 4 . 49 Downcomer l iq u id tem p eratu res fo r c a se 6B.

3683

4.89

600-57Z3■THCTA « 1

• THCTA « 2 THETA - 3

•THETA « 4 •THETA « 6 •THETA - 6

U 420

1000 2000 3000 4000 5000 0000

F ig u re 4 .5 0 Downcomer l i q u i d t e m p e r a t u r e s f o r c a s e 6C.

4 . 9 0

14000-

^ , £3000-

u*** 10000* O WWWbZSbU 8000- 8u aooo- u .«0 22 4000-1 t -H ____< 2000-£

— r - - r - '■■■ “-I—8000

TIME (s)•000 TOOO 8000

F i g u r e 4 .5 1 H e a t - t r a n s f e r c o e f f i c i e n t s f c r c a s e 6A.

4 . 9 1

The sequence i s i n i t i a t e d by a 2 - in . - d i a m b re a k in th e snrge l i n e midway

betw een th e p r e s s u r i z e r and r i s e r o f th e h o t l e g .

F o llow ing th e i n i t i a t i o n o f the b re a k , th e r e a c t o r and tu r b in e t r i p from

f u l l power. R eac to r decay h e a t was s p e c i f i e d as 1 .0 t im es th e ANS

s ta n d a r d . For t h i s t r a n s i e n t c a l c u l a t i o n , th e ICS and a l l key system

components were assumed to f u n c t i o n c o r r e c t l y . The on ly s p e c i f i e d o p e r a to r

a c t i o n was th e RCP t r i p 30 s a f t e r HPI a c t u a t i o n . Two c a se s in v o lv in g

HPI t h r o t t l i n g to system su b co o lin g were i n v e s t i g a t e d . One c a l c u l a t i o n

i n v e s t i g a t e d th e e f f e c t s o f HPI t h r o t t l i n g to 42 + 1 2 .5 K su b co o lin g and

th e o th e r i n v e s t ig a t e d th e e f f e c t s o f no HPI t h r o t t l i n g . The t h r o t t l e d

HPI case was n o t run because th e su b co o lin g m argin was n e v e r a c h ie v e d .

Table 4 .1 7 g iv e s th e sequence o f e v e n ts f o r the c a l c u l a t i o n . F ig u re s 4 .52

th ro u g h 4 .5 4 p r e s e n t th e r e s u l t s of th e c a l c u l a t i o n and e x t r a p o l a t i o n s w ith

and w ith o u t LPI o p e r a t io n assumed.

TRAC c a l c u l a t e d a r e l a t i v e minimum in te m p era tu re a t ap p ro x im a te ly 1000 s

i n t o th e t r a n s i e n t : th e p r e s s u r e a t 1000 s was 6 .2 MPa. The te m p era tu re

and p r e s s u r e were b o th d e c re a s in g a t the end o f the c a l c u l a t i o n a t 3760

s and had v a lu e s o f 450 K and 2 .1 MPa r e s p e c t i v e l y .

The c a l c u l a t e d minimum downcomer l i q u i d te m p e ra tu re s n e v e r approached the

c u r r e n t NOT v a lu e o f Oconee-1 f o r two re a s o n s : (a ) v e n t v a lv e flow mixing

w i th the f l u i d in th e downcomer r e g io n and (b) c a l c u l a t e d loop o s c i l l a t i o n s .

However, i f th e c a l c u l a t i o n were c o n t in u e d , th e LPI system would a c t u a t e as

a r e s u l t o f th e d e p r e s s u r i z a t i o n . The a d d i t i o n o f LPI would p ro b a b ly r e s u l t

i n downcomer l i q u i d te m p e ra tu re s approach ing o r exceed ing th e c u r r e n t NDT

4 . 9 2

Table 4 .1 7 Hot le g b re a k LOCA — 2 - i n . b re a k sequence o f e v en ts

EventTime

(s)

Break opens 0 .0

R eac to r and tu r b i n e t r i p s 0 .5

TSVs c lo s e (b o th loops) 0 .5

TBVs open (b o th loops) 4 .2

HPI a c t u a t i o n 43.1

TBVs o p e n /c lo s e (b o th loops) 51.0

RCPs t r i p 71.0

MFV rea l ig n m e n t 73.1

TBVs o p e n /c lo s e (b o th loops) 75.7

Vent v a lv e s open 100

ICS c lo s e s SHFCVs 300

Candy canes rem ain vo ided 500

Minimum downcomer te m p e ra tu re ( 470 K; 6 .2 MPa) 750

Loop flow o s c i l l a t i o n s b e g in 1200

Accumulator i n j e c t i o n b e g in s 1750

End o f c a l c u l a t i o n 3670

4 . 9 3

-MOO

EXTRAPOLATED (NO L P I)-OOG

•»00EXTRAPOLATED (L P I)

-soo

-•00

0 1000 •000 woo3000 woo 4000 •ooom c(«)

F igure 4 . 5 2 2 -in ..-d la m SBLOCA e x tr a p o la te d system p r e s su r e .

•00

au-

500-

4M-

400-EXTRAPOLATED (NO L P I)

S7S--300

335-EXTRAPOLATED (L P I)

275-7000•000woo40003000

M

in

TlM CCs)

F igure 4 . 5 3 2 - in .-d ia m SBLOCA e x tr a p o la te d downcomer l iq u id tem p eratu re .

4.94

18000

p 16000- 2

^ 14000-

12000-

10000-Cbblo

0000-

q:bl^ 0000- Z

« 4000-

U 2000- X

EXTRAPOLATED (NO L P I)^ ------ Ik

EXTRAPOLATED (L P I)A-' -' A.

n i l ii Ji>l

1000 aooo aooo 40oo w oo aooo tooo TIME (a)

F ig u r e 4 .5 4 2 - i n . - d i a m SBLOCA e x t r a p o l a t e d downcomer h e a t - t r a n s f e r c o e f f i c i e n t .

4 . 9 5

o f the Oconee-1 p l a n t . Hovevex, t h i s t r a n s i e n t may no t be i a ^ o r t a n t in

te rm s o f PIS because th e p rim ary system p r e s s u r e w i l l be q u i t e low when

th e downcomer l i q u i d te m p e ra tu re f a l l s below th e NOT l i m i t .

4 . 3 . 2 . 6 Small B reak LOCA 4 - I n . Hot Leg Break

The 4 - in . - d i a m h o t leg b re a k LOCA c a l c u l a t e d by LANL i s t r a n s i e n t 48 (LANL

14) in Tab le 4 .2 5 . T h is t r a n s i e n t i s i n i t i a t e d by a 4 - in . - d i a m b re a k in

th e surge l i n e midway between th e p r e s s u r i z e r and the r i s e r p o r t i o n o f the

h o t l e g .

F o llow ing th e i n i t i a t i o n o f th e b re a k , th e r e a c to r and tu r b i n e t r i p from

f u l l power. R eac to r decay h e a t was s p e c i f i e d as 1 .0 t im es th e ANS s ta n d a rd .

In t h i s t r a n s i e n t , th e ICS and a l l key components a re assumed to fu n c t io n

c o r r e c t l y . The o n ly s p e c i f i e d o p e r a to r a c t i o n was th e RCP t r i p 30 s a f t e r

HPI a c t u a t i o n .

Table 4 .1 8 g iv e s th e sequence o f e v e n ts f o r th e c a l c u l a t i o n . F ig u re s 4 .55

th ro u g h 4 .57 suounarize th e r e s u l t s o f th e c a l c u l a t i o n and e x t r a p o l a t i o n to

7200 seco n d s . TRAC c a l c u l a t e d a minimum downcomer l i q u i d te m p e ra tu re of

350 K; th e system p r e s s u r e a t t h i s minimum te m p e ra tu re was 1 .0 MPa.

Adequate f l u i d mixing betw een th e v e n t -v a lv e f l u i d and th e c o ld le g (HPI)

f l u i d in th e downcomer a t the c o ld le g ju n c t i o n m a in ta in e d th e downcomer

l i q u i d te m p e ra tu re s above 450 K. However, th e a c t u a t i o n o f the LPI

system a t 1240 s dropped th e downcomer te m p e ra tu re s v ery r a p i d l y and below

th e c u r r e n t NDT v a lue (365 K) f o r th e Oconee-1 p l a n t . Even though the

downcomer l i q u i d te m p e ra tu re s were c a l c u l a t e d to be below th e c u r r e n t

4 . 9 6

Table 4 .1 8 Small-break LOCA — 4 - in . Hot Leg Break

TimeEvent (s )

Break opens 0 .0

T urb ine and r e a c t o r t r i p 0 .5

T nrb ine s to p v a lv e s c lo se 0 .5

Secondary s id e b e a t e r and b e a t e r d r a in t r i p 1 .0

Condenser feed from tu r b in e t r i p 1 .5

TBV loop A opens f o r f i r s t time 4 .4

TBV loop B opens f o r f i r s t time 4 .8

HPI system a c t u a t i o n on low p rim ary system p r e s s u r e 16 .8

TBV loops A and B o p e n /c lo s e 117.4

RCPs t r i p 30 s a f t e r HPI a c t u a t i o n 4 6 .8

MFW is r e a l ig n e d t o SGs upper h e a d e r 46 .8

MFCV o v e r r id e t r i p 46 .8

TBV loops A and B o p e n /c lo se 92.1

Candy canes v o id 125.0

ICS c lo s e s SUFCVs 300.0

Accumulator i n j e c t i o n loop A ( f i r s t tim e) 540.7

Accumulator i n j e c t i o n loop B ( f i r s t tim e) 541.0

Accumulator i n j e c t i o n s c e a se s 678.6

Accumulator i n j e c t i o n loop A 726.1

Accumulator i n j e c t i o n loop B 784.5

A ccumulator i n j e c t i o n c e a se s 828.7

Accumulator i n j e c t i o n loop A 921.4

A ccumulator i n j e c t i o n loop B 925.7

4 . 9 7

Table 4 .1 8 (continued)

TimeEvent ( s)

Accumulator i n j e c t i o n c e a se s loop B 947.5

Accumulator i n j e c t i o n c e a se s loop A 947.7

A ccum ulator i n j e c t i o n s (b o th lo o p s ) 1100.0

LPI system a c t u a t i o n on low p r im ary system p r e s s u r e 1236.0

End o f c a l c u l a t i o n 1400.0

4 . 9 8

e x t r a p o l a t e d

. -too

-400

-aoo

7000 MOO0 MOO MOO1000 2000 MOO 4000

5• I

TlME(s)

F ig u re 4 . 5 5 4 - in .-d ia m SBLOCA e x tr a p o la te d system p r e s su r e .

-M O

9 M -

-M O

EXTRAPOLATEDsoo-

-400

-ttOaeo-

«oo 2000 MOO 7000

F ig u re 4 . 5 6 4 - in .-d ia m SBLOCA e x tr a p o la te d downcomer l iq u id tem p eratu re .

4.99

IBOOO

^ 14000-EXTRAPOLATED

12000

U 6000-

•0000 1000 •000 7000•000 6000 •0004000TIME (i)

F ig u r e 4 .5 7 4 - i n . - d i a m SBLOCA e x t r a p o l a t e d downcomerh e a t - t r a n s f e r c o e f f i c i e n t .

4 . 1 0 0

NDT Oconee-1, t h i s c a l c n l a t i o n cou ld n o t be c o n s id e re d a s i g n i f i c a n t PTS

t r a n s i e n t because r e p r e s s u r i z a t i o n d id n o t o ccu r .

4 .3 .2 .7 S tea n G en e ra to r Dryout Follow ed by EFW Overfeed

The t r a n s i e n t f e a t u r e s s te a n g e n e r a to r d ryou t fo llow ed by emergency

feed w ate r o v e r fe e d modeling the Rancho Seco t r a n s i e n t s as c l o s e l y as

p o s s i b le on th e Oconee-1 p l a n t system . T h is sequence i s t r a n s i e n t 49 (LANL

15) on T ab le 4 .2 5 . The a c c id e n t sequence began as a lo s s -o f -m a in feed w ate r

t r a n s i e n t (MFW pumps t r i p ) . The EFW-control v a lv es f a i l e d to open on

demand bu t were s u b se q u e n t ly m anually opened by the o p e r a to r . A lso , th e

RCPs rem ained on d u r in g th e t r a n s i e n t , and th e EFW to th e SGs was no t

t e rm in a te d u n t i l 4200 s . The p rim ary system r e p r e s s u r i z a t i o n was l im i te d

to 1 3 .8 NPa as a r e s u l t o f th e o p e r a t o r ' s t h r o t t l i n g the HPI system.

Table 4 .19 g iv e s th e sequence o f e v e n ts f o r the c a l c u l a t i o n . F ig u re s 4 .5 8

th rough 4 . ( 0 summarize th e c a l c u l a t i o n and e x t r a p o la t io n s to 7200 s . At

4200 s th e minimum downcomer f l u i d te m p e ra tu re o f 452 K was r e p o r te d . At

th e same i n s t a n t , system p r e s s u r e was 1 3 .8 MPh. Both tem pera tu re and p r e s ­

su re were assumed to in c re a s e over the e x t r a p o l a t i o n p e r io d .

4 .4 E v a lu a t io n o f Flow S t r a t i f i c a t i o n E f f e c t s

The TRAC and RELAP5 codes cannot p r e d i c t th e fo rm a t io n o f co ld w a te r plumes

and s i m i l a r flow s t r a t i f i c a t i o n e f f e c t s . S t r a t i f i c a t i o n occu rs when co ld

and h o t s tream s a re b ro u g h t to g e th e r w i th o u t s u f f i c i e n t tu rb u le n c e to mix

them. Cold HPI f l u i d , b e in g d e n s e r , may form a l a y e r a t the bottom of

th e co ld le g p ip in g below th e b u lk o f th e warmer f l u i d in the c o ld le g .

T h is l a y e r o r plume cou ld run a long th e co ld le g to th e v e s s e l and s p i l l

4 . 1 0 1

Table 4 .1 9 S te a a g e n e r a to r d ryon t f o l lo v e d by EFW o y erfeed (Ranobo S eeo - ty p e ) t r a n s i e n t sequence o f e v en ts

EventTiae

(s )

MFW pnaps t r i p , IffCVs and SUFCVs c lo s e 0 .0

TSVs c lo s e (b o tb loops) 0 .0

R eac to r t r i p s on h ig b p r e s s n r e 4 .4

TBYs a c tu a te d 4.6

PORV a c tu a te d 226.4

EFW i n i t i a t e d t o b o tb SGs 540.0

HPI a c tu a te d on low p r e s s u r e 738.0

HPI t h r o t t l e d t o l i a i t r e p r e s s u r i z a t i o n 1255.0

EFW t e r a i n a t e d t o b o tb SGs 4200.0

M iniaua v e s s e l douncoaer l i q u i d t e a p e r a t u r e ( 452 K) c a l c u l a t e d

4200.0

C a l c u l a t i o n t e r a i n a t e d 4300.0

4 . 1 0 2

MOOSCO «ooe

F igu re 4 .5 8 Rancho S e c o -ty p e t r a n s ie n t e x tr a p o la te d system p r e s su r e .

COO-coo

SCO

-M2

•00-

JCO

440 - I -c ■000•0004000

F ig u re 4 . 5 9 Rancho S e c o -ty p e t r a n s ie n t e x tr a p o la te d downcomer l iq u id tem p era tu re .

4.103

16000

14000

t 12000

11000•0001000 6000

F ig u r e 4 .6 0 Rancho S e c o - ty p e t r a n s i e n t e x t r a p o l a t e d downcomer h e a t - t r a n s f e r c o e f f i c i e n t s .

4 . 1 0 4

down along th e downcoaer w a l l , p ro d u c in g lo c a l i z e d c o ld t e a p e r a tn r e s on

th e downcoaer which cou ld g r e a t l y i a p a c t th e f r a c t u r e p r o b a b i l i t y fo r the

v e s s e l . F a c to r s a f f e c t i n g p lu a e d e v e lo p a e n t in c lu d e HPI no zz le and co ld

leg g e o a e t r y , c o ld le g b u lk flow and t e a p e r a t u r e c o n d i t io n s , ven t v a lve

flow r a t e s and t e a p e r a t u r e s , and downcoaer g e o a e try .

4 3This s e c t i o n s u a a a r i z e s a rev iew by T.G. Theophanous, ’ Purdue U n iv e r s i t y ,

o f th e INEL- and LA N L-ealculated t r a n s i e n t s f o r flow s t r a t i f i c a t i o n e f f e c t s .

The approach o f th e rev iew in c lu d ed th e use o f s c reen in g c r i t e r i a based

on e a p i r i c a l and t h e o r e t i c a l a i z in g a o d e l s to i d e n t i f y th e c a se s where flow

s t r a t i f i c a t i o n aay o c c u r . Suspect c a se s were su b je c te d t o d e t a i l e d a i z in g

c a l c u l a t i o n s to d e t e r a in e p luae e z t e n t and t e a p e r a t u r e . The a i z in g a o d e l

was henchaarked a g a i n s t e z p e r i a e n t s in a h a l f - s c a l e t e s t f a c i l i t y s e t up

fo r th e Oconee-1 g e o a e t ry .

The s c re e n in g c r i t e r i a e l i a i n a t e d a l l b u t seven o f th e d e t a i l e d c a l c u l a t i o n s

f r o a c o n s id e r a t io n o f s t r a t i f i e d flow . The INEL cases f o r which no

s t r a t i f i c a t i o n was p r e d i c t e d w ere: r e v i s e d a a i n s t e a a l i n e b re a k , s tu c k

open PORV, s t e a a g e n e r a to r o v e r fe e d , a a z ia u a s u s t a in a b le o v e r fe e d , and

s t e a a g e n e r a to r tube r u p tu r e . LANL c a s e s in c lu d e d TBV c a se s SB, 5C, 6A,

6b, and 6C; th e a a i n s t e a a l i n e b re a k c a s e s ; PORV LOCA; and the s te a a

g e n e r a to r d ry o u t fo llow ed by EFV o v e r f i l l c a s e s .

For th e seven r e a a in in g t r a n s i e n t s , i t was d e te r a in e d t h a t the TRAC

and RELAP c a l c u l a t e d b u lk t e a p e r a tu r e s were ad eq u a te . The rea so n s a re

s u a a a r iz e d below .

4 . 1 0 5

The LANL 4 - l n . h o t leg b re a k t r a n s i e n t e x h ib i te d v e ry low p r e s s n r e when

s t r a t i f i c a t i o n wonld p r e v a i l ( a f t e r 300 s) . With t h i s low p r e s s n r e and

tw o-phase flow c o n d i t io n s in th e downcomer, th e t r a n s i e n t was n o t a PIS

co n ce rn .

The INEL RC pnmp s n c t io n b re a k a l s o had v e ry r a p id d e p r e s s n r i z a t i o n . An

asjrmmetric s t a g n a t io n c o n d i t io n p r e v a i l e d w i th v en t v a lv e f low s eqnal to

o r g r e a t e r than th e n n s ta g n a te d loop f lo w s . C a lc n la te d plnme te m p era tn re s

s ta y e d w i th in 10 °C o f th e b n lk te m p e ra tn re of th e flow ing lo o p . The

s t ro n g v e n t v a lv e flow w i l l a l s o b re a k np th e plnm es.

The INEL p r e s s n r i z e r sn rge l i n e b re a k shows s t a g n a t io n in loop A between 750

and 1250 s and in loop B betw een 1000 and 2500 s i n t o th e t r a n s i e n t . S trong

v e n t v a lv e flow d u r in g th e s e p e r io d s broke np th e p lnm es. A lso , p la n a r

plnme m ixing c a l c n l a t i o n s showed r e s t r i c t i o n s to plnme l a t e r a l growth snch

t h a t th e l o n g i tu d in a l w elds were n o t a f f e c t e d .

The LANL two-lBV f a i l u r e case (5A) i s a h ig h - p r e s s u r e t r a n s i e n t w ith one

f low ing loop (A) and one s ta g n a n t loop (B ) . Vent v a lv e flow i s s t ro n g ,

and i s e f f e c t i v e a t m ixing th e downcomer. The plnmes f o r th e s ta g n a n t loop

were found to be on ly 10 c o ld e r th a n th e flow ing lo o p .

The INEL o r i g i n a l main s te a m lin e b reak case i s a l s o a h ig h - p r e s s u r e

t r a n s i e n t . Loop B s t a g n a t e s betw een 250 and 950 s . Loop A s ta g n a te s

betw een 200 and 350 s and a g a in betw een 650 and 950 s . Vent v a lv e flow i s

s t r o n g o v e r th e se p e r io d s . T em peratures o f 450 K (350°F) were c a l c u l a t e d

a t th e s ta g n a te d c o ld le g n o z z l e s . The s tro n g v en t v a lv e f low s p rev en ted

th e growth o f th e plumes o ver th e l o n g i tu d in a l w elds .

4 . 1 0 6

The INEL four-TBV f a i l u r e a t h o t s tandby case i s a h ig h -p re s s u re t r a n s i e n t

in which th e re was n o t s t a g n a t io n o r v en t v a lv e f low . However, th e low loop

f low s n e r i t e d concern f o r plume developm ent. The RELAP5 model p r e d ic te d

o s c i l l a t i n g f low s , w hich, i f a c t u a l l y en co u n te re d , would g e n e ra te e x c e l l e n t

m ix ing . Even i f plume development were s i g n i f i c a n t , th e e x c e l l e n t co ld

le g mixing c h a r a c t e r i s t i c s and th e g e n e ra l cooldown o f the system would

m inim ize th e d i f f e r e n c e betw een b u lk and plume te m p e ra tu re s .

The LANL 2 - i n . h o t le g b re a k case i s a lo w -p re s su re t r a n s i e n t . This case

i s s i m i l a r to th e co rre sp o n d in g INEL c a s e .

In summary, th e mixing geom etry o f the co ld le g s and th e s t ro n g v en t va lve

flow s m i t ig a t e d bo th th e r e l a t i v e te m p era tu re d ec re ase and the spread of

plumes in h ig h - p r e s s u r e t r a n s i e n t s . I n lo w -p re s s u re t r a n s i e n t s th e plumes

cou ld be c o ld e r , b u t th e low p r e s s u r e s n u l l i f i e d the impact to r i s k of

v e s s e l f a i l u r e .

4 .5 E ^ trgpg jlg tpd Segppncgs

4 .5 .1 Methodology

4 . 5 .1 . 1 G eneral Approach

A f te r an i n i t i a l su rvey o f th e da ta re s o u rc e s and of the sequences

i d e n t i f i e d f o r e s t i m a t io n , a f i v e - s t e p p ro c e s s was developed f o r the

e s t i m a t io n o f Oconee-1 p r e s s u r e , te m p e ra tu re , and h e a t t r a n s f e r c o e f f i c i e n t

p r o f i l e s . T h is approach a llow ed lo g i c a l r e d u c t io n of the number of cases

t o be e v a lu a te d and d e r iv e d th e g r e a t e s t b e n e f i t from the in fo rm a tio n in

4 . 1 0 7

th e TRAC and RELAP c a l c n l a t i o n s . The approach i s d is c u s s e d f u r t h e r in

Appendix C.

The f i r s t s te p in v o lv ed th e g roup ing o f s i m i l a r sequences . An e v a l u a t i o n

o f th e TRAC and RELAP c a l c u l a t i o n s f o r th e e f f e c t s from d i f f e r e n t o p e ra t in g

s t a t e s p ro v id e d th e c r i t e r i a f o r ass ignm ent o f sequences i n t o g roups .

B es id es p ro v id in g g roup ing c r i t e r i a , s te p 2 developed th e p a ram e te rs f o r

th e cooldown model used on o c c a s io n f o r t h i s s tu d y . To a s s u re c o r r e c t

i n t e r p r e t a t i o n o f c o n d i t io n s du r in g seq u en ces , th e a p p ro p r ia te p a ram e te rs

would he a p p l ie d t o th e cooldown model to d u p l i c a t e p o r t i o n s o f sequences

c a l c u l a t e d by TRAC o r RELAP. T his v a l i d a t i o n e f f o r t took p la c e i n s te p 3 .

I n s te p 4 , th e p r e s s u r e , te m p e ra tu re , and h e a t t r a n s f e r c o e f f i c i e n t s were

e s t im a te d . T em perature cou ld be e s t im a te d e i t h e r by p ie cew ise a p p l i c a t i o n

o f TRAC and RELAP r e s u l t s o r by c a l c u l a t i o n u s in g th e cooldown model.

The method s e l e c t i o n depended on th e com p lex ity of the sequence and the

a v a i l a b i l i t y o r absence o f d i r e c t l y a p p l i c a b l e d a ta from the TRAC o r

RELAP c a l c u l a t i o n s . E a r ly p o r t i o n s of sequences where HPI, fe e d w a te r ,

and p r im ary loop f low s and downcomer te m p e ra tu re s v a ry r a p id l y were no t

d i r e c t l y a p p l i c a b le to th e cooldown model, so p ie cew ise use o f TRAC and

RELAP d a ta was a p p l i e d . L ate in t r a n s i e n t s when th e loop f low s a re more

s t a b l e , a cooldown model was a p p l ie d to p r e d i c t the te m p e ra tu re s t r e n d s .

The cooldown model i s an energy b a la n c e which acco u n ts f o r th e h e a t in g

and cooldown mechanisms p r e s e n t in th e Oconee-1 system . The cooldown

model was most u s e f u l where th e e n d - s t a t e c o n f ig u r a t io n s in th e r e q u e s te d

sequence e v a lu a t io n s d e v ia te d s i g n i f i c a n t l y from those in th e TRAC and

4 . 1 0 8

RELAP c a l c u l a t i o n s . The d e r i y a t i o n o f th e cooldown model i s a l s o in c lu d ed

in Appendix C.

P re s s u re e s t im a te s were d e r iv e d s o l e l y from o b s e r v a t io n o f p r e s s u re t r e n d s

in th e TRAC and RELAP c a l c u l a t i o n s . The a b i l i t y o f th e h ig h -h ead HPI system

in th e Oconee-1 p l a n t to q u ic k ly r e p r e s s u r i z e th e p rim ary was r e f l e c t e d by

th e TRAC and RELAPS c a l c u l a t i o n s . The p r e s s u r e b e h a v io r of the v a r io u s

c a l c u l a t i o n s was s u f f i c i e n t l y un ifo rm to su g g es t t h a t p ie cew ise s e l e c t i o n

o f TRAC and RELAP p r e s s u r e c u rv e s was v a l i d .

Heat t r a n s f e r c o e f f i c i e n t s were based on p ie cew ise s e l e c t i o n of TRAC d a ta .

In g e n e r a l , th e c a l c u l a t i o n s p r e d ic te d r e l a t i v e l y c o n s ta n t v a lu e s w hile

th e r e a c t o r c o o l in g pumps (RCP) a re runn ing and s te p down to a lower bu t

c o n s ta n t v a lu e a f t e r RCP t r i p and e s ta b l i s h m e n t o f n a t u r a l c i r c u l a t i o n .

The h e a t t r a n s f e r c o e f f i c i e n t s p r e d ic te d by TRAC d id n o t in c lu d e c o r r e c t io n

f o r f r e e c o n v e c t io n e f f e c t s . T h e re fo re , th e v a lu e s were u n d e rp re d ic te d f o r

n a t u r a l c i r c u l a t i o n flow c o n d i t i o n s . T h is e f f e c t was compensated f o r in

th e f r a c t u r e m echanics c a l c u l a t i o n s by s p e c i fy in g a minimum h e a t t r a n s f e r0 r\

c o e f f i c i e n t o f 600 B tu /h f t F (3400 W/m^K). Any lower v a lu e s re p o r te d

in t h i s s e c t i o n o r th e appendix were superceded by th e s p e c i f i e d l i m i t .

The com pleted e s t im a t io n s were documented in s te p 5 . T h is docum entation

com prises S e c t io n s C.3 th ro u g h C.8 o f Appendix C.

4 . 5 . 1 . 2 Sequence Grouping

The o v e rc o o l in g sequence ev en t t r e e s fo rm u la ted by ORNL p o sse ssed over

6 .7 m i l l i o n e n d - s t a t e s . A p p l ic a t io n of a 10 ^ / y r s c re e n in g l i m i t on even t

f requency reduced th e number o f sequences r e q u i r i n g s p e c i f i c e s t im a te to

4 . 1 0 9

u n d er 100. These were grouped in t o sm all s e t s by i n i t i a t o r , t h a t i s

tu r b i n e bypass v a lv e f a i l u r e s a t f u l l power, tu r b i n e bypass v a lv e f a i l u r e s

a t h o t s ta n d b y , POBY-sized LOCA, feed w ate r o v e r fe e d s , steam g e n e r a to r tube

r u p t u r e s , and main steam l i n e b r e a k s .

Some a d d i t i o n a l g rouping o f sequences b ased on component s t a t e s '

s i m i l a r i t i e s f u r t h e r reduced th e number o f e s t im a te s to 97 . However,

g rouping by component s t a t e s ( i . e . , v a lv e s t i c k s open, ICS f a i l s t o runback

fe e d w a te r , e t c . ) does n o t accoun t f o r th e th e rm a l -h y d ra u l ic impact o f such

s t a t e s . The a c t u a l iaq>act w i l l a l s o depend on the f u n c t io n o r f a i l u r e

o f o th e r system s and on feedback from th e rm a l -h y d ra u l ic impact o f such

s t a t e s . By o b s e r v a t io n and e v a lu a t io n o f s i m i l a r e v en ts in the THAC and

RELAP c a l c u l a t i o n s , th e c o n t r i b u t i n g e v e n ts in a sequence were c l a s s i f i e d

as dom inant, m inor , o r in c o n s e q u e n t i a l . Sequences w ith the same dominant

e v e n ts were grouped t o g e th e r f o r a n a l y s i s . I n l a t e r s t e p s , th e in f lu e n c e

o f minor e v e n ts was e v a lu a te d where p o s s i b l e t o check th e c o n s is te n c y of

th e g ro u p in g s . Some sequences were r e a s s ig n e d to o th e r groups based on

th o se ch eck s .

The sequence g roup ings and th e r e s u l t s o f sequence e x t r a p o l a t i o n a re

p r e s e n te d by i n i t i a t o r in th e fo l lo w in g s e c t i o n s .

4 . 5 .2 T u rb ine Bypass Valve F a i l u r e s a t F u l l Power

E v a lu a t io n o f t u r b i n e bypass f a i l u r e s a t f u l l power concerned th e 19

c a s e s i d e n t i f i e d in Tab le 4 .2 0 . The t a b l e l i s t s th e s p e c i f i e d c o n d i t io n s ,

which in c lu d e v a r io u s com binations o f f a i l e d TBYs, feed w ate r system

perfo rm ance , p r im ary p r e s s u r e c o n t r o l s , and o p e r a to r a c t i o n s . These cases

4 . 1 1 0

Table 4.20 Fnll-power TBV failure case groupings

ConditionCase (TBV-)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Secondary Pressure Controls

1 TBV open SGA1 TBV open SGA, SGB1 TBV open SGA, 1 SBV open SGA

Feedwater

MFW runback as designed MFW overfeed SGA, high level trip MFW overfeed both SGs, HL trip MFWP trip at time =0.0 EFW control to level

X X Z Z X X X X X

X

X X XX X X X

X X

X X X X X X X X X X

X X X

X X

X X X X

X X X X X X X X X X X X X X X X X X X

Table 4.20 (continued)

ConditionCase (TBV-)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

E£iffiS^X_E£es&Mfc„Cgat£ols

POSV block valve closedPORV operates properly

e«PORF fails to reseat eeSRV fails to reseat

x z x x x x z z X X X X

X X X

Operator Actions

RCP tripped at HPI + 30 s No other actionsSG isolation at 20 min, SGB restored at 21 min HPI throttled later of 22 min or 50^F subcooling 1 RCP/loop restart later of 22 min or 50^F

subcooling

X X X X X X X X X X

X X X X XX X X X

X X X X

X X X X

X

XX

X

X

X

X

X

X X

X X

X

X

X

X

X

X

Group number (TBVG-) 1 1 2 3 2 3 4 5 1 6 8 7 6 4 6 5 9 10 10

Other conditions common to all cases: full power« decay heat 1.0 times ANS, all ECCS components operate as designed

If challenged

were c o n s o l id a te d i n t o th e 10 groups in d i c a te d a t the bottoai of Table

4 .2 0 . These groups r e p r e s e n t t r a n s i e n t s 1 (IBVGl) th rough 10 (TBVGIO) on

Table 4 .2 5 . F ig u re s 4 .5 1 th rough 4 .53 g iv e the e x t r a p o la te d p r e s s u r e s ,

te m p e ra tu re s , and h e a t t r a n s f e r c o e f f i c i e n t s f o r groups 1 , 2 , 4 , 5 , and

7 . These groups a re r e p r e s e n t a t i v e of a l l groups as a w hole. Groups 3

and 8 co rresp o n d c l o s e l y to group 2 , which i s in th e f i g u r e . L ikew ise ,

group 9 i s s i m i l a r to group 4 , and groups 4 and 10 a re s im i l a r to group 5

in t h e i r r e s p o n s e s . S e c t io n C.4 o f Appendix C p ro v id e s d e t a i l e d in d iv id u a l

e v a lu a t io n s o f th e se g ro u p s . The u n i fo rm i ty of te m p era tu re t r e n d s i s in

keeping w ith the mechanisms d r iv in g the cooldown. Group 2 , th e on ly group

to ex p e r ie n c e r e h e a t in g , does so upon th e d ryou t of the a f f e c t e d steam

g e n e ra to r a f t e r fee d w a te r i s o l a t i o n . Groups 1 , 5 and 7 a l l f e a t u r e p ro p e r

ICS feed w ate r c o n t r o l so t h a t th e steam g e n e ra to r s a re no t f looded o u t .

T h e re fo re , th e s e groups c l u s t e r t o g e th e r l a t e in th e sequences, a l th o u g h

th e e q u iv a le n t of two s tu ck -o p en TBVs a r e in groups 5 and 7 vs on ly one

in group 1 . In TBV group 4 , an ICS f a i l u r e a l low s con tin u ed flow of main

feed w a te r (from the h o tw e l l and condensa te pumps) t o f lo o d the a f f e c t e d

steam g e n e r a to r ( s ) . T h is i s the case a l s o f o r the LANL two-TBV f a i l u r e

and four-TBV f a i l u r e c a s e s . (The two-TBV b ase case (5A) v a lu e s were

th e r e f o r e g iv e n to TBVG4.) T h is f lo o d in g produces th e low est e x t r a p o la t e d

te m p e ra tu re s . The minimum te m p e ra tu re s f o r TBV groups 1 , 2 , 4 , 5 , and 7

a re 420 K, 471 K, 355 K, 398 K, and 405 K r e s p e c t i v e l y .

4 .5 .3 T u rb ine Bypass Valve F a i l u r e s a t Hot Standby

E v a lu a t io n o f t u r b i n e bypass v a lve f a i l u r e s a t h o t s tandby invo lved th e fo u r

ca se s i d e n t i f i e d in T ab le 4 .2 1 . The t a b l e l i s t s th e c o n d i t io n s modeled.

4 . 1 1 3

O TBVGl.PA TBVG2.P + ”TBVG4P‘‘ 'x^ T B V G ey o TBVG7N.P

80006000 6000 70001000 2000 3000 40000TIME ( seconds )

Figure 4.61 Extrapolated downcomer pressures for Oconee-1TBV - full power cases.

O TBVGl.TA TBVG2.T + "TBVG4!f‘' x~TBVG6.T~' O TBVG7N.T

eooo6000 70004000TIME ( seconds )

600030001000 2000

Figure 4.62 Extrapolated downcomer temperatures for Oconee-1TBV - full power cases-

O TBVG1.HA TBVG2.H + "TBVG4!h '

'x ‘ TBVG6.H'o TBVG7N.H

ooE-» 1

w'

&oot - 4

K

1000 0000 4000 5000TIME ( seconds )

6000 7000 6000

Figure 4.63 Extrapolated dovmcomer heat transfer coefficientsfor Oconee-1 TBV - full power cases.

Table 4 .2 1 Hot standby TBV f a i lu r e cases

C o n d it io n s

Case

ITBV 2TBV ITBV

(12 h r ) (12 h r) (1 wk)

2TBV

(1 wk)

I n i t i a l C o n d it io n s

Hot s tandby

Decay h e a t l e v e l s

a . 12 h r s = 15 .75 MW

b . 1 wk = 7 .5 MW

Secondary P re s s n re C on tro l

1 TBV opens SGA

2 TBVs open SGA

SGB TBV's o p e r a te as des igned

SSRVs o p e ra te as des ig n ed

X

X

X

X

X

X

X

X

X

X

Feedw ater c o n t r o l l e d to

a p p r o p r ia t e l e v e l

re C on tro l

PORV o p e r a t e s as des ig n ed

RCPs t r i p p e d a t HPI + 30 s

Assumes p o s t RCP t r i p SG l e v e l m a in ta in e d by w hatever feed w ate r source a v a i l a b l e .

4 . 1 1 7

v h ic h in c lu d e d one and two v a lv e f a i l u r e s a t power l e v e l s co rre sp o n d in g to

12 h and 1 wk a f t e r shutdown. These c a se s co rresp o n d to t r a n s i e n t s 24

(ZPITBV). 25 (ZP2TBV). 33 (WITBV), and 34 (VZTBV) on T able 4 .2 5 . F ig u re s

4 .6 4 th ro u g h 4 .6 6 g ive th e e x t r a p o la t e d p r e s s u r e s , te m p e ra tu r e s , and h e a t

t r a n s f e r c o e f f i c i e n t s f o r the c a s e s . The t e a p e r a t u r e t r e n d s show t h a t

decay h e a t e f f e c t s a re a o s t n o ta b le a t the end o f the sequences where

an o f f s e t of 14^C s e p a r a t e s th e co r re sp o n d in g o n e -v a lv e and tw o-valve

f a i l u r e s . The a i n i a u a t e a p e r a t u r e s f o r ZPllBV, ZP2TBV, ZWITBV, and ZW2IBV

a re 385 K, 371 K, and 358 K. The f a i l u r e to i s o l a t e the s t e a a g e n e ra to r s

and t h r o t t l e HPI le d to low er t e a p e r a tu r e s th an were o b ta in e d f o r the INEL

four-TBV f a i l u r e a t h o t s tan d b y c a l c u l a t i o n .

4 . 5 .4 POBV-Sized LOCA Cases

Nine PORV-sized LOCA sequences i d e n t i f i e d f o r e v a l u a t i o n a re l i s t e d in

T ab le 4 .2 2 . These a re reduced to f i v e g roups , as i n d i c a te d a t th e bottom o f

Tab le 4 .2 2 . These groups a re t r a n s i e n t s 11 (PSBGl) th ro u g h 15 (PSBG5) in

T ab le 4 .2 5 . F ig u re s 4 .6 7 , 4 .6 8 , and 4 .69 g ive th e e x t r a p o la t e d p r e s s u r e s ,

t e a p e r a t u r e s , and h e a t t r a n s f e r c o e f f i c i e n t s f o r g roups 1 , 3 , 4 , and 5 .

Group 2 i s v e ry s i m i l a r t o group 1 . D e ta i l e d d e s c r i p t i o n s o f th e groups and

th e e x t r a p o l a t i o n p ro c e d u re a re a v a i l a b l e in Appendix C, S e c t io n C .6 . The

main d i f f e r e n c e s between th e sequences a re due to th e feed w a te r s i t u a t i o n

accompanying the p r im ary b r e a k . The PORV-sized LOCA r e s u l t s in s u f f i c i e n t

HPI flow so t h a t n e a r l y a l l o f the decay h e a t can be absorbed by the

p r im a ry , even e a r l y in th e t r a n s i e n t . L a t e r , a f t e r th e decay h e a t has d ied

down, th e HPI i s ab le t o coo l th e system somewhat. In t h i s s i t u a t i o n ,

l i t t l e o r no steam i s g e n e ra te d in th e s e c o n d a r i e s . T h e re fo re , b o th normal

4 . 1 1 8

VO

Q ZP1TBV.PA ZW1TBV.P + ‘*ZP2TBV.P x"ZW2TBV‘P

< §

1000 2000 3000 iOOO

TIME ( seconds )5000 6000 7000 6000

Figure 4*64 Extrapolated downcomer pressures for Oconee-1TBV failure at hot stand-by cases.

N5O

§O ZPITBV.T

§

I

— ©

§

870004000 5000 6000 60000 1000 2000 3000

TIME ( seconds )

Figure 4,65 Extrapolated downcomer temperatures for Oconee—1TBV failure at hot stand-by cases.

4>*h-»ho

csiHU-t

&oot~* I a '

O ZP1TBV.HA ZW1TBV.H + ' ZP2TBV.H

‘x'ZWBTBVii

aOJa

wou

■■4000

■ r ■" 50002000 7000 6000

TIME ( seconds )

Figure 4.66 Extrapolated downcomer heat transfer coefficientsfor Oconee-1 TBV failure at hot stand-by cases.

Table 4 .2 2 POKV-sized LOCA cases and groupings

Case SBLOCA-*

C o n d it io n 1 2 3 4 5 6 7 8 9

Secondary P r e s s u r e C o n tro ls

O p era te s as d es igned X z z z X z z z

2 TBVs f a i l open loop A z

FpotfwutorMFl runback as d es igned z z z

SGA runback f a i l u r e z z z

LOMFW a t t i n e » 0 .0 z z z

EFV o p e r a te s as d es igned z z z z z z z

EFW in manual z z

P rim ary P r e s s u r e C o n tro ls

PORV b lo c k y a ly e open z z z z z z z z z* * * * *

PORV o p e ra te s as des ig n ed z z z z z z z z z**

SRV f a i l s t o r e s e a t z z z

O p era to r A c tio n s

RCP t r i p p e d a t HPI -i- 30 s z z z z z z z z z

F u l l EFV flow a f t e r SG d ry o u t z z

I s o l a t e s SGs a t 20 min z

Group number (PSBG-) 1 2 3 2 4 5 1 2 3

*O ther c o n d i t io n s coauion to a l l c a s e s : f u l l power , decay h e a t 1 .0 tim es

• •

• • •

ANS, a l l ECCS coaiponents o p e r a te as d es igned

I f c h a l le n g e d»Break i s POKV-sized and may o ccu r anyvhere

4 . 1 2 2

N>LO

O PSBGl.P

« 8 -

1000 2000 3000 4000TIME ( seconds )

5000 6000 7000 eooo

w

w

Figure 4.67 Extrapolated downcomer pressures for Oconee-1 PORV-sized LOCA cases.

ho

O PSBGl.TA PSBG3.T + ‘pSBG4‘t X~PSBG5.T

----------

60007000600050003000 4000TIME ( seconds )

j20001000

Figure 4.68 Extrapolated downcomer temperatures for Oconee-1 PORV-sized LOCA cases.

N>Ln

C\JHOi,XXHOQ

OO

O PSB G 1.H A PSB G 3 .H

’ + " P S B G 4 .H ’x 'P S B G 5 -H

Wcv}X

4UooHw

4000TIMK ( s e c o n d s )

7000

Figure 4.69 Extrapolated downcomer heat transfer coefficientsfor Oconee-1 PORV—sized LOCA cases.

f e e d v a te r o p e r a t io n (PSBGl) and NFW o v e rfeed w ith t r i p on SG l e v e l (PSBG2)

have th e sane in f lu e n c e s in c e th e steam g e n e ra to r s a r e f i l l e d once and o n ly

once . Group 3 s t a r t s ou t c o o l e r i n i t i a l l y becau se of th e e x c lu s iv e use of

c o ld EFW to f i l l th e steam g e n e r a to r s to th e l e v e l f o r n a t u r a l c i r c u l a t i o n .

The steam g e n e ra to r s are> in e f f e c t , t o t a l l y i s o l a t e d and do n o t c o n t r i b u t e

f u r t h e r to system cooldown. In group 4 , th e EFW le v e l c o n t r o l f a i l s and

th e steam g e n e ra to r s f lo o d o u t , a l lo w in g th e steam g e n e r a to r s t o work w ith

th e HPI to coo l th e system to v ery low te m p e ra tu r e s . In group 5 , th e

i s o l a t i o n o f th e s tu c k -o p e n TBVs a l lo w s a te m p e ra tu re reco v e ry upon lo s s o f

t h i s cooldown mechanism. The minimum te m p e ra tu re s f o r c a se s PSBGl th rough

PSBG5 a re 472 K, 474 K, 459 K, 350 K, and 436 K. The f i n a l downcomer

p r e s s u r e in each case i s 11 .5 MPA.

4 . 5 .5 F eedw ater O verfeed Cases

Seven feed w a te r o v e r fe e d c a s e s were o r i g i n a l l y i d e n t i f i e d f o r e v a lu a t io n .

L a t e r , a v e ry m ild e ig h th case was added. The seven ca se s appear as

t r a n s i e n t s 16 (FWl o r OVRFDl) th ro u g h 22 (FW7 o r 0VRFD7) in Table 4 .2 5 .

Tab le 4 .23 p r e s e n t s th e c o n d i t io n s f o r th e se c a s e s . F ig u re s 4 .7 0 th rough

4 .7 2 g iv e th e e x t r a p o la t e d p r e s s u r e s , te m p e ra tu r e s , and h e a t t r a n s f e r

c o e f f i c i e n t s f o r c a s e s 1 , 3 , 6 , 7 , and the new case number 8 ( l o s s of main

fe e d w a te r w ith subsequen t r e f i l l w ith EFW c o n t r o l l e d to l e v e l ) . With the

e x c e p t io n o f case 6 , a l l o f the t r a n s i e n t s a re v e ry m ild . Cases 2 and

4 a r e s i m i l a r to case 1 . Case 6 a c h iev es low te m p e ra tu re s because of an

e x t e n s iv e EFW o v e rfe e d s i m i l a r to th e Rancho S eco -type t r a n s i e n t . Minimum

te m p e ra tu re s f o r c a se s FWl th rough FW8 a re 560 K, 560 K, 530 K,- 550 E,

560 E, 419 E, 537 E, and 560 E.

4 . 1 2 6

Table 4 .23 Feedwater tr a n s ie n t cases

*C o n d it io n 1 2

Case FW- (o r

3 4

OVRFD-)

5 6 7

Main Feedw ater

SGA runback f a i l u r e X X X

Both SG runback f a i l u r e X X

LOMFW a t time - 0 .0 X X

MFWP t r i p h ig h SG l e v e l z X X X

MFWP h ig h SG l e v e l t r i p f a i l u r e X

Emeraencv Feedw ater

EFW works as des igned X X X X X

EFW on manual X X

O n era to r A c tio n s

RCP t r i p a t HPI + 30 s X X X X X

F a i l to t r i p RCP X X

EFW r e s t o r e d f u l l flow a t 20 min X

NFW r e s t o r e d f u l l flow a t 20 min X

•C o n d i t io n s common to a l l c a s e s : f u l l power. decay h e a t 1 .0 tim es ANS,secondary p r e s s u r e c o n t ro l system s o p e ra te as d e s ig n ed , p r im ary p r e s s u re c o n t r o l system o p e ra te as d e s ig n e d , a l l ECCS components o p e ra te as des igned

4 . 1 2 7

< I1—4 ,S '

77- 7 7

/ /

7/ “

O FW1.P A FW3.P + ''f W6.P

"x ' fwY po FW8.P

— o

N500

wPi

a.

2000 3000 4000TIME ( seconds )

5000 7000

Figure 4.70 Extrapolated downcomer pressures for Oconee-1feedwater transient cases.

6000

roVO

UOi

I ' I ■■'■ ■ ■” 'r3000 4000 5000

TIME ( seconds )

o FWl.TA FW3.T+ FW6.TX FW7.T0 FW8.T

>

•“H—K A

’ ■ ■ ' I ' " ' "7000 aooo

Figure 4.71 Extrapolated downcomer temperatures for Oconee-1feedwater transient cases.

U)o

OFWl.H

o

1000 2000 3000 6000 60004000TIME ( seconds )

7000 eooo

Figure 4,72 Extrapolated downcomer heat transfer coefficientsfor Oconee-1 feedwater transient cases.

4 . 5 .6 S te a a G en e ra to r Tube R upture

Tbe steam g e n e ra to r tube r u p tu r e I s e s s e n t i a l l y a sm a l l -b re a k LOCA t h a t

dumps th e l o s t p r im ary c o o la n t i n t o th e steam g e n e r a to r . For a s in g le tube

r u p t u r e , th e INEL SGTR c a l c u l a t i o n in S e c t io n 4 . 3 . 1 . 9 a p p l i e s d i r e c t l y . For

m u l t i p l e tube r u p t u r e s , th e PORV-sized LOCA e x t r a p o la t i o n s would g e n e r a l ly

be r e p r e s e n t a t i v e . In e i t h e r e v e n t , th e te m p era tu re and p r e s s u r e response

o f th e Oconee-1 p l a n t shou ld be m i ld as f a r as FTS i s concerned .

4 . 5 .7 Main Steam L ine Break Cases

Seven main steam l i n e b re a k c a s e s were e v a lu a te d . Table 4 .2 4 l i s t s th e

c o n d i t io n s f o r th e se c a s e s . The sequences com prise t r a n s i e n t s 26 (MSLBl)

th ro u g h 32 (MSLB7) r e s p e c t i v e l y in Tab le 4 .2 5 . F ig u re s 4 .73 th rough

4 .75 p r e s e n t the e x t r a p o la t e d p r e s s u r e s , te m p e ra tu re s , and h e a t t r a n s f e r

c o e f f i c i e n t s f o r c a se s HSLBl, MSLB3, NSLB4, and HSLB6. Cases HSLB2 and

7 co rre sp o n d c l o s e l y t o NSLBl. L ikew ise , MSLB5 i s v e ry s im i l a r to MSLB3.

E x t r a p o la t io n o f th e se sequences was p ro b le m a tic because of th e d i s p a r i t y

o f s p e c i f i c a t i o n s between th e RELAP5 and TRAC d e t a i l e d c a l c u l a t i o n s and

th e s e e x t r a p o la t e d c a s e s .

Most n o ta b ly , th e 20-min d e la y o f fe e d w a te r i s o l a t i o n , RCP r e s t a r t , and HPI

f o r the e x t r a p o la t e d c a se s r e p r e s e n te d a v e ry long d e la y r e l a t i v e to the

e a r l y RCP r e s t a r t s and i s o l a t i o n o f feed w a te r a t 10 min in th e LANL and

INEL main steam l i n e b re a k c a l c u l a t i o n s . The r a p id cooldown r a t e s in the

d e t a i l e d c a l c u l a t i o n s ( se e S e c t io n s 4 . 3 . 1 . 4 and 4 . 3 .2 . 1 ) cou ld n o t p o s s ib ly

be s u s t a in e d f o r 20 min. The cooldown model in Appendix C cou ld no t be

a p p l i e d because th e complex tw o-phase h e a t t r a n s f e r regime in th e a f f e c t e d

4 . 1 3 1

Table 4 .2 4 Main steaai l in e break stndy cases

C o n d it io n

Case MSLB-

1 2 3 4 5

Secondary P r e s s u r e C o n tro l

TSVs c lo s e on tu r b i n e t r i p s ig n a l X X X X X X X

TBVs o p e r a te as d e s ig n ed X X X X X X X

SSBVs o p e ra te as d e s ig n ed ( i f c b a l le n g e d ) X X X X X X X

NFV runback c o n t r o l l e d by ICS X X X

NFV o v e r fe e d b o th s t e a a g e n e ra to r s X

NFV o v e rfe e d to b ro k en s t e a a g e n e ra to r X

NFV puBp t r i p on b ig b s t e a a g e n e ra to r X X

le v e l (HV puaps , CB puaps c o n t in u e to

o p e ra te )

NFV puaps t r i p a t t i a e = 0 .0 0 X X

EFV i n i t i a t e s on s e t p o in t X X X X X X

EFV f a i l s t o i n i t i a t e a u t o a a t i c a l l y X

EFV c o n t r o l l e d t o l e v e l X X X X X

EFV o v e r fe e d t o b ro k en s t e a a g e n e r a to r X

f i i w r y cp .p trp i

PORV b lo c k v a lv e open X X X X X X X**

PORV o p e r a t e s as des ig n ed X X X X X X• *

PORV f a i l s t o r e s e a t X• •

SRVs o p e ra te d as des ig n ed X X X X X X X

4 . 1 3 2

Table 4 .2 4 (oontinned)

C o n d i t io n

Case MSLB-

3 4 5

O pera to r A c tio n s

RCPs t r i p p e d a t HPI + 30 s

Both SGs i s o l a t e d a t 20 min

Both SG's i s o l a t e d a t 5 min

EFW and TBVs r e s t o r e d t o i n t a c t SG

a t 21 min

EFW and TBVs r e s t o r e d t o i n t a c t SG

a t 6 min

HPI t h r o t t l e d a t l a t e r o f 22 min

o r 50**F snbcoo ling

1 RCP/loop r e s t a r t e d a t l a t e r o f 22

min o r 50°F sn b co o lin g

F a i l e d PORV i s o l a t e d when system

p r e s s u r e d rops below 2400 p s i

X X X X X X X

X X X X X X

X

X X X X X X

X

X X X X X X X

X X X X X X X

X

*O ther c o n d i t io n s common to a l l c a s e s : f u l l power, decay h e a t 1 .0 t im es ANS, ECCS system s o p e ra te as des igned

*•I f c h a l le n g e d

4 . 1 3 3

u>■p-

O MSLB1.P-a

<I

§

§

o6000 7000 90001000 4000 50000 2000 3000

TIME ( seconds )

Figure 4.73 Extrapolated downcomer pressures for Oconee-1main steam line break cases.

LOUi

§O MSLBl.T

§

%

§

§

§

87000 eooo2000 60000 1000 3000 4000 5000

TIME ( seconds )

Figure 4.74 Extrapolated downcomer temperatures for Oconee-1main steam line break cases.

O MSLB1.HA MSLB3.H + "msLB41h

"x "MSLB6.H

cvja

OJON

pq

&ouH JK '

' Pm Oof-K

rr

1000 2000 3000 4000 5000TIME ( seconds )

6000 7000 8000

Figure 4.75 Extrapolated downcomer heat transfer coefficientsfor Oconee-1 main steam line break cases.

s t e a a g e n e ra to r v i o l a t e s th e m o d e l 's s i a p l i f y i n g a s s n a p t io n s ( see Appendix

C, S e c t io n C .2 .3 ) . A lso , th e n a t u r a l c i r c u l a t i o n flow d a ta n e c e s sa ry to

s e t up th e model were c u t s h o r t by the e a r l y r e s t a r t o f th e r e a c t o r co o l in g

puaps .

As a r e s u l t , a v e ry sia ip le approach was ta k e n to e x t r a p o la t e th e se c a s e s .

F i r s t , th e LANL a a i n s t e a a l i n e b reak ca se s were s e l e c t e d as th e base s

f o r e x t r a p o l a t i o n , as th e y p r e d ic t e d th e most severe cooldown r a t e s . Next,

the downcomer te m p e ra tu re re sponse of th e e x t r a p o la t e d ca se s was ta k en to

be s i m i l a r to th e p o r t i o n o f th e LANL case p r i o r to the r e s t a r t o f the

RCPs a t 526 s . C on tinu ing on th e same s lo p e , th e downcomer tem p era tu re

was e x t r a p o la t e d to a minimum te m p e ra tu re o f 373 K (212*^F). This minimum

te m p e ra tu re i s c o n s id e re d a c o n s e r v a t iv e p h y s ic a l l i m i t .

The te m p e ra tu re rem ains a t t h i s minimum l i m i t u n t i l the steam g e n e ra to r

d r i e s o u t . The en tra in m e n t of l i q u i d s from the b roken steam g e n e ra to r

i s assumed to a b a te a t low te m p e ra tu re s , a l low ing th e steam g e n e ra to r to

r e f i l l . The time to steam g e n e ra to r d ry o u t r e f l e c t s th e time needed to

accum ula te s u f f i c i e n t decay h e a t and RCP power d i s s i p a t i o n to complete

th e steam g e n e ra to r d ry o u t . R ehea ting and r e p r e s s u r i z a t i o n t r e n d s from

th e LANL c a se s were employed to com plete th e e x t r a p o la t i o n a f t e r steam

g e n e r a to r d r y o u t .

The te m p e ra tu re e x t r a p o l a t i o n s f o r MSLBl, MSLB3, and MSLB4 in F ig u re 4 .74

were b ased on th e above a s su m p tio n s . The d i f f e r e n c e s in th e se cu rves can be

a s c r ib e d to th e q u a n t i t y o f w a te r accum ula ted in th e b roken steam g e n e ra to r s

p r i o r to i s o l a t i o n . The NSLB6 c ase does n o t ex p e r ien ce o v e rco o l in g due to

th e l o s s o f a l l feed w ate r fo llow ed by e a r l y i s o l a t i o n o f the b roken steam

4 . 1 3 7

g e n e r a to r and c o n t r o l l e d cooldown u s in g th e i n t a c t s t e a a g e n e r a to r . See

Appendix C, S e c t io n C .3 , f o r d e t a i l e d d i s c u s s io n o f th e s e t r a n s i e n t s .

4 .6 Suaaary o f T h e ra a l-H y d ra u l ic E v a lu a t io n s

P r e s s u r e , t e a p e r a t u r e , and h e a t t r a n s f e r c o e f f i c i e n t re sp o n se p r o f i l e s were

c a l c u l a t e d and a s s ig n e d f o r eve ry ev en t t r e e e n d - s t a t e hav ing a frequency

o f o ccu rre n c e g r e a t e r than 10 ^ p e r y e a r . The use of sequence s i a i l a r i t y

g roup ings f u r t h e r reduced th e nuaber o f sequences e v a lu a te d .

D e ta i l e d c a l c u l a t i o n s u s in g th e RELAPS and TRAC a o d e l s p ro v id ed the

d a ta upon which sequence e x t r a p o l a t i o n s were d eve loped . The d e t a i l e d

c a l c u l a t i o n s in c lu d ed even t i n i t i a t o r s known o r s u sp e c te d to r e s u l t in

s i g n i f i c a n t o v e rc o o l in g r e s p o n s e s . These i n i t i a t o r s in c lu d e d s t e a a l i n e

b r e a k s , t u r b i n e bypass v a lv e f a i l u r e s , feed w ate r o v e r f e e d s , s t e a a g e n e ra to r

tube r u p t u r e s , and sm all p r im ary b r e a k s . The RELAPS and TRAC models

developed f o r t h i s s tudy w ere , a t the t i a e , th e most complex a p p l i c a t i o n s

o f th e codes t o d a t e .

E x t r a p o la t io n s were based on th e r e s u l t s o f th e d e t a i l e d c a l c u l a t i o n s .

Where s p e c i f i e d c o n d i t io n s o f an e x t r a p o la t e d t r a n s i e n t c l o s e l y laatched

th o se of a c a l c u l a t e d sequence , th e c a l c u l a t e d r e s u l t s ( i . e . , p r e s s u r e

and t e a p e r a t u r e t r e n d s ) were used o v er the a p p l i c a b l e p o r t i o n o f the

e x t r a p o l a t i o n . T e a p e ra tu re e x t r a p o l a t i o n s were f a c i l i t a t e d by the use

o f a cooldown model, which accoun ted f o r a l l major h e a t in g and c o o lin g

mechanisms and the system mass and loop mass f low s d e te rm in in g th e time

c o n s ta n t s on th e r e sp o n s e .

4 . 1 3 8

The r e s u l t s o f th e e z t r a p o l s t i o n s and d e t a i l e d c a l c u l a t i o n s a re su a n a r iz e d

on T ab le 4 .2 5 . The t r a n s i e n t nnmbers and i d e n t i f i c a t i o n s c o r r e l a t e to

th e noaiencla tn re used in th e f r a c t u r e aiechanics (C hap te r 5 .0 ) and r e s u l t s

(C h ap te r 6 .0 ) s e c t i o n s . The minimuai downcomer te m p era tu re s and e x te n t of

p r im ary r e p r e s s u r i z a t i o n f a c i l i t a t e r e f e r e n c e s to the f r a c t u r e mechanics

c a l c u l a t i o n .

4 . 1 3 9

Table 4 .2 5 Sunmary o f Oconee-1 PTS therm al-hdran lic an a lyses

T r a n s ie n t T r a n s ie n t D e s c r ip t io n / Nnnber Nane A l t e r n a t e Naae

Minimnm S e c t io n Tem perature

R eference T min (K)

Maximum P r e s s u r e a t

o r a f t e r T min (MPA)

1 TBVGl C .4 .1 420 16 .8

2 TBVG2 C .4 .2 471 16 .8

3 TBVG3 C .4 .3 462 16 .8

4 TBVG4 C .4 .4 365 16 .8

5 TBVG5 C .4 .5 402 1 6 .8

6 TBVG6 C .4 .6 398 11 .5

7 TBVG7 C .4 .7 406 16 .8

8 TBVG8 C .4 .8 449 16 .8

9 TBVG9 C .4 .9 365 16 .8

10 TBVGl0 C .4 .10 386 11 .5

11 PSBGl C .6 .1 472 11.5

12 PSBG2 C .6 .2 473 11.5

13 PSBG3 C .6 ,3 459 11.5

14 PSBG4 C .6 .4 350 11 .5

15 PSBG5 C .6 .5 436 11 .5

16 OVRFDl FWl C .7 .1 562 15 .0

17 0VRFD2 FW2 C .7 .1 562 15 .0

18 0VRFD3 FW3 C .7 .2 530 16 .8

19 0VRFD4 FW4 C .7 .3 550 1 6 .8

20 0VRFD5 FW5 C .7 .4 562 1 5 .0

21 0VRFD6 FW6 C .7 .5 419 1 6 .8

22 0VRFD7 FW7 C .7 .6 536 16 .8

23 SGTR C .8 .0 505 17 .0

24 ZPITBV C .5 .0 385 16 .8

25 ZP2TBV C .5 .0 371 16.5

26 MSLBl C .3 .1 373 1 6 .8

4 . 1 4 0

Table 4 . 25 (ContinTied)

T r a n s ie n tNumber

T r a n s ie n tName

D e s c r ip t io n / A l t e r n a t e Name

Minimum S e c t io n Tem perature

R eference T min (K)

Maximum P re s su re a t

o r a f t e r T min (MPA)

27 MSLB2 C .3 .2 373 16 .8

28 MSLB3 C .3 .3 373 16.8

29 MSLB4 C.3 .4 373 16.8

30 MSLB5 C .3 .5 373 16 .8

31 MSLB6 C .3 .6 541 16 .8

32 MSLB7 C .3 .7 373 16.8

33 WITBV ZWITBV C .5 .0 370 16 .8

34 W2TBV ZW2TBV C .5 .0 358 16 .8

35 LANU MSLE (b ase ) 4 .3 .2 .1 405 17 .0

36 LANLZ (vo id )

37 LANU MSLB (P a ra 2) 4 .3 .2 .1 475 7 .7

38 LANU MSLB (P a ra 3) 4 .3 .2 .1 450 12 .8

39 LANU PORV LOCA 4 .3 .2 .2 528 11.5

40 LANU Oconee-3

41 LANL7 TBV (5A) 4 .3 .2 .3 365 17 .0

42 LANL8 TBV (5B) 4 .3 .2 .3 440 17 .0

43 LANL9 TBV ( 5 0 4 .3 .2 .2 430 4 .0

44 LANUO TBV (6A) 4 . 3 .2 . 4 350 17 .0

45 LANLll TBV (6B) 4 .3 .2 .4 465 17 .0

46 LANL12 TBV ( 6 0 4 . 3 .2 . 4 350 4 .0

47 LANU3 LOCA 2 ” 4 . 3 .2 . 5 425 2 .8

48 LANL14 LOCA 4" 4 .3 .2 .6 320 0.3

49 LANL15 Rancho Seco 4 .3 .2 .7 452 17 .0

50 LANL16 (vo id )

51 INEU MSLB (R evised) 4.3 .1 .4 494 17 .0

52 INEU PORV LOCA 4 .3 .1 .3 545 11.4

4 . 1 4 1

Table 4 . 25 (Continued)

T r a n s ie n tNumber

T r a n s ie n tName

D e s c r ip t i o n / A l t e r n a t e Name

S e c t io nR eference

Minimum Tem perature

T min (K)

Maximum P re s s u re a

o r a f t e r T min (MPA

53 INEL3 O verfeed 4 .3 .1 .2 505 17 .0

54 INEL4 Oconee-3

55 INEL5 LOCA 2" 4 . 3 .1 . 7 355 1 .5

56 INEL6 Max. Sus. NFV 4 . 3 .1 . 5 500 17 .0

57 INEL7 4TBV-HS 4 . 3 .1 . 6 387 17 .0

58 INEL8 Pump S u c t io n 2 .5 " 4 . 3 . 1 . 8 446 5 .2

59 INEL9 SGTR 4 . 3 . 1 . 9 505 17 .0

4 . 1 4 2

REFERENCES

4 .1 C. D. F l e t c h e r and o t h e r s , "RELAPS T herm al-H ydrau lic A n a ly s is of

P r e s s n r i z e d Thermal Shock Sequences f o r the Oconee-1 P r e s s u r i z e d Water

R e a c to r , " E6G-NSMD-63343, J u ly 1983.

4 .2 J . I r e l a n d and o t h e r s , "TRAC A n a ly s is o f Severe O vercooling T r a n s ie n t s

f o r the Oconee-1 PWR," LA-UR-83-3182, (no d a t e ) .

4 .3 T. G. Theophanous, Purdue U n iv e r s i t y , l e t t e r to J . D. White, ORNL,

December 22 , 1983.

4 . 1 4 3

5.0 CONDITIONAL PROBABILITY OF VESSEL FAILURE

R. D. C h e v e r to n , Oak R id g e N a t io n a l L a b o r a to ry

5.1 Introduction

The c o n d i t i o n a l p r o b a b i l i t y o f v e s s e l f a i l u r e ( t h r o u g h - w a l l c r a c k in g )

w as c a l c u l a t e d f o r th e O conee-1 r e a c t o r p r e s s u r e v e s s e l . The n e c e s s a r y

m o d e ls f o r p e r f o r m in g a p r o b a b i l i s t i c f r a c t u r e - m e c h a n i c s a n a l y s i s f o r

t h e O c o n e e -1 r e a c t o r p r e s s u r e v e s s e l an d t h e r e s u l t s o f th e a n a l y s i s a r e

d i s c u s s e d .

5 .2 D e s c r i p t i o n o f B a s ic P ro b lem

D u rin g a n o v e r c o o l i n g t r a n s i e n t i n a p r e s s u r i z e d - w a t e r r e a c t o r (PWR),

t h e r e a c t o r p r e s s u r e v e s s e l i s s u b j e c t e d t o th e rm a il sh o c k i n t h e s e n s e

t h a t th e r m a l s t r e s s e s a r e c r e a t e d i n t h e v e s s e l w a l l a s a r e s u l t o f

r a p i d re m o v a l o f h e a t fro m i t s i n n e r s u r f a c e . The th e rm a l s t r e s s e s a r e

s u p e r im p o s e d o n t h e p r e s s u r e s t r e s s e s w i t h t h e r e s u l t t h a t t h e n e t

s t r e s s e s a r e p o s i t i v e ( t e n s i l e ) a t and n e a r t h e i n n e r s u r f a c e o f t h e

w a l l and a r e s u b s t a n t i a l l y lo w e r an d p e r h a p s n e g a t i v e e l s e w h e r e , d e p e n d ­

in g o n th e m a g n i tu d e o f t h e p r e s s u r e s t r e s s . The c o n c e r n o v e r t h e h ig h

t e n s i l e s t r e s s e s n e a r t h e i n n e r s u r f a c e i s t h a t th e y r e s u l t i n h ig h

s t r e s s i n t e n s i t y f a c t o r s (K ^) f o r i n n e r - s u r f a c e f l a w s t h a t may be

p r e s e n t . To com pound t h e m a t t e r , t h e r e d u c e d t e m p e r a tu r e a s s o c i a t e d

w i t h t h e th e r m a l s h o c k an d r a d i a t i o n dam age r e s u l t i n r e l a t i v e l y low

f r a c t u r e to u g h n e s s v a l u e s f o r t h e v e s s e l m a t e r i a l , p a r t i c u l a r l y n e a r t h e

5.1

i n n e r s u r f a c e . T h u s , t h e r e i s a p o s s i b i l i t y o f p r o p a g a t i o n o f i n i t i a l l y

v e r y s h a l lo w a s w e l l a s d e e p e r f l a w s , an d t h e p r o b a b i l i t y i n c r e a s e s w i th

t im e b e c a u s e o f t h e t im e d e p e n d e n c e o f r a d i a t i o n d am ag e .

The p o s i t i v e g r a d i e n t i n t e m p e r a t u r e an d t h e n e g a t i v e g r a d i e n t s i n

s t r e s s an d f l u e n c e th r o u g h t h e w a l l t e n d t o p r o v id e a m ech an ism f o r

c r a c k a r r e s t . E ven s o , i f t h e c r a c k i s v e r y lo n g o n t h e s u r f a c e and

p r o p a g a t e s d e e p e n o u g h , t h e r e m a in in g v e s s e l l i g a m e n t w i l l becom e p l a s ­

t i c , an d t h e v e s s e l i n t e r n a l p r e s s u r e w i l l u l t i m a t e l y r e s u l t i n r u p t u r e

o f t h e v e s s e l . T h u s , f o r e a c h th e r m a l t r a n s i e n t t h e r e w i l l b e a maximum

p e r m i s s i b l e p r e s s u r e t h a t i s a f u n c t i o n o f t h e t im e t h a t t h e v e s s e l h a s

b e e n i n o p e r a t i o n .

C ra c k p r o p a g a t io n may a l s o b e l i m i t e d by a phenom enon r e f e r r e d t o a s

warm p r e s t r e s s i n g (W PS), w h ic h h a s b e e n d e m o n s t r a te d i n t h e l a b o r a t o r y

w i t h s m a l l sp e c im e n s^ an d a l s o i n a r a t h e r l a r g e , t h i c k - w a l l e d c y l i n d e r

2d u r i n g a th e r m a l - s h o c k e x p e r im e n t . I n s u c h c a s e s , WPS s im p ly r e f e r s t o

t h e i n a b i l i t y o f a c r a c k t o i n i t i a t e w h i l e i s d e c r e a s i n g w i th t im e ,

t h a t i s , w h i l e t h e c r a c k i s c l o s i n g . W h ile t h i s s p e c i a l s i t u a t i o n i s

e n c o u n te r e d d u r in g som e s p e c i f i c o v e r c o o l i n g a c c i d e n t s , c a u t i o n m u s t be

e x e r c i s e d i n t a k i n g c r e d i t f o r WPS b e c a u s e c h a n g e s i n t h e p r e s s u r e t h a t

a f f e c t l i t t l e e l s e c a n d e l a y o r e l i m i n a t e t h e r e q u i s i t e c o n d i t i o n s f o r

WPS.

The a r e a o f th e v e s s e l o f p a r t i c u l a r c o n c e rn i n t h e e v e n t o f a n o v e r ­

c o o l i n g a c c i d e n t (OCA) i s t h e s o - c a l l e d b e l t l i n e r e g i o n , t h a t i s , t h e

5.2

a r e a d i r e c t l y a c r o s s f r c a i t h e c o r e w h e re (1 ) t h e r a d i a t i o n dam age i s t h e

g r e a t e s t , ( 2 ) t h e th e r m a l s h o c k c o u ld b e s e v e r e , an d (3 ) a r u p t u r e o f

t h e v e s s e l c o u ld p r e c lu d e f l o o d i n g o f t h e c o r e . W h e th e r o r n o t a p a r ­

t i c u l a r d e g r e e o f r u p t u r e a s s o c i a t e d w i t h a p a r t i c u l a r t r a n s i e n t c o u ld

i n f a c t p r e c lu d e f l o o d i n g o f t h e c o r e h a s n o t b e e n d e te r m in e d . F o r th e

p u rp o s e o f t h i s r e p o r t , i t i s s u f f i c i e n t t o p r e d i c t w h e th e r a f l a w w i l l

p r o p a g a t e c o m p le te ly th r o u g h t h e w a l l o f t h e v e s s e l .

The r a d i a t i o n - i n d u c e d r e d u c t i o n i n f r a c t u r e to u g h n e s s o f t h e v e s s e l

m a t e r i a l i s p r i m a r i l y a f u n c t i o n o f t h e f a s t - n e u t r o n f l u e n c e an d th e

c o n c e n t r a t i o n s o f c o p p e r ( a c o n ta m in a n t ) and n i c k e l ( a n a l l o y i n g e l e ­

m e n t ) . I n m o s t PWR v e s s e l s t h e h i g h e s t c o n c e n t r a t i o n s o f c o p p e r a r e

fo u n d i n t h e w e ld s t h a t j o i n t h e s e g m e n ts o f t h e v e s s e l , and many o f

t h e s e w e ld s h a v e h ig h c o n c e n t r a t i o n s o f n i c k e l a s w e l l . T h u s , f o r some

PWR v e s s e l s t h e w e ld s a r e o f p r im a r y c o n c e r n , an d t h e O c o n e e -1 r e a c t o r

p r e s s u r e v e s s e l f a l l s i n t h i s c a t e g o r y .

The b e l t l i n e r e g i o n o f r e a c t o r p r e s s u r e v e s s e l s i s f a b r i c a t e d u s in g

e i t h e r f o r g e d - r i n g s e g m e n ts o r r o l l e d - p l a t e s e g m e n ts . V e s s e l s made w i th

f o r g i n g s h a v e o n ly c i r c u m f e r e n t i a l w e ld s , w h i le p l a t e - t y p e v e s s e l s h av e

b o th c i r c u m f e r e n t i a l an d a x i a l w e ld s , a s show n i n F ig u r e 5 . 1 . F o r

p l a t e - t y p e v e s s e l s w i th s t a g g e r e d a x ie i l w e ld s an d f o r w h ic h r a d i a t i o n

deimage i s m uch m ore s e v e r e i n t h e w e ld s t h a n i n t h e b a s e m a t e r i a l , t h e

f i n a l s u r f a c e l e n g t h o f a p r o p a g a t i n g i n n e r - s u r f a c e a x i a l f la w t e n d s t o

b e l i m i t e d t o t h e l e n g t h o f t h e a x ie i l w e ld i n w h ic h i t r e s i d e s , t h a t i s ,

5.3

t h e h e i ^ t o f t h e s h e l l c o u r s e . F u r th e r m o r e , o n ly t h a t p o r t i o n o f a

w e ld t h a t i s w i t h i n t h e a x i a l b o u n d s o f t h e c o r e n ee d b e c o n s id e r e d

b e c a u s e o f t h e s t e e p a t t e n u a t i o n o f t h e f a s t - n e u t r o n f l u x b ey o n d t h e

f u e l r e g i o n .

The e x te n d e d l e n g t h o f a n i n i t i a l l y s h o r t , c i r c u m f e r e n t i a l l y o r i e n t e d

f l a w l o c a t e d i n a c i r c u m f e r e n t i a l w e ld a l s o t e n d s t o be l i m i t e d b e c a u s e

o f a n a z im u th a l v a r i a t i o n i n t h e f a s t - n e u t r o n f l u x ( s e e F ig u r e 5 . 1 ) .

The b e h a v io r o f an assu m ed f la w c a n b e p r e d i c t e d f o r a g i v e n t r a n s i e n t

u s i n g f r a c t u r e - m e c h a n i c s m e th o d s o f a n a l y s i s . I n s u c h a n a n a l y s i s t h e

p a r a m e te r s an d c o n s i d e r a t i o n s i n v o l v e d a r e t h e s i z e , s h a p e , an d o r i e n t a ­

t i o n o f t h e f l a w ; t h e th e r m a l an d p r e s s u r e s t r e s s e s r e s u l t i n g fro m a

s p e c i f i c t r a n s i e n t ; t h e t e m p e r a t u r e an d f a s t - n e u t r o n f l u e n c e d i s t r i b u ­

t i o n s th r o u g h o u t t h e v e s s e l w a l l ; t h e e f f e c t o f f l u e n c e a n d m a t e r i a l

c h e m is t r y on r a d i a t i o n dameige; a v a r i e t y o f m a t e r i a l p r o p e r t i e s ; an d a

c o m p a r is o n o f t h e s t r e s s i n t e n s i t y f a c t o r (K ^) a s s o c i a t e d w i th t h e t i p

o f t h e f l a w w i th t h e m a t e r i a l ’ s s t a t i c c r a c k - i n i t i a t i o n an d c r a c k - a r r e s t

f r a c t u r e - t o u g h n e s s v a l u e s an d . E ach o f t h e s e f a c t o r s m u s t be

c o n s i d e r e d i n t h e d e v e lo p m e n t o f a n a p p r o p r i a t e a n a l y t i c a l m odel f o r

e v a l u a t i n g t h e i n t e g r i t y o f a PWR v e s s e l w hen s u b j e c t e d t o OCA l o a d i n g

c o n d i t i o n s . The n e c e s s a r y m o d e ls f o r p e r fo rm in g a p r o b a b i l i s t i c

f r a c t u r e - m e c h a n i c s a n a l y s i s f o r t h e O c o n e e -1 r e a c t o r p r e s s u r e v e s s e l and

t h e r e s u l t s o f t h e a n a l y s i s a r e d i s c u s s e d i n t h e r e m a in d e r o f t h i s

c h a p t e r .

5.4

O R N L - D W G 8 2 - 5 1 6 2 A ETD

F L U E N C ED I S T R I B U T I O N

A X I A L W E L D

O U T L I N E O F C O R E

C R O S S S E C T I O N O F R P V T H R O U G H C O R E

A X I A L W E L D

C I R . W E L D

D E V E L O P E D V I E W O F B E L T L I N E R E G I O N O F R P V

F ig u r e 5 . 1 . C ro s s s e c t i o n an d d e v e lo p e d v ie w o f p l a t e - t y p e PWR p r e s s u r e v e s s e l .

5.5

5 .3 C a l o u l a t l o n a l M o d els

The c o n d i t i o n a l p r o b a b i l i t y o f v e s s e l f a i l u r e ( t h r o u g h - w a l l c r a c k i n g )

w as c a l c u l a t e d f o r t h e O co n ee-1 r e a c t o r p r e s s u r e v e s s e l u s i n g t h e OCA-P

3c o d e . OCA-P a c c e p t s a s i n p u t t h e p r im a ry s y s te m p r e s s u r e , t h e te m p e ra ­

t u r e o f t h e c o o l a n t i n t h e r e a c t o r v e s s e l dow ncom er, a n d t h e f l u i d - f i l m

h e a t t r a n s f e r c o e f f i c i e n t a d j a c e n t t o t h e v e s s e l w a l l , a l l a s a f u n c t i o n

o f t im e i n a s p e c i f i e d OCA t r a n s i e n t . The co d e t h e n p e r fo rm s o n e ­

d im e n s io n a l th e r m a l an d s t r e s s a n a l y s e s f o r t h e v e s s e l w a l l an d f i n a l l y

a p r o b a b i l i s t i c f r a c t u r e - m e c h a n i c s a n a l y s i s . D e t a i l s o f OCA-P n e c e s s a r y

f o r a n u n d e r s t a n d in g o f t h e O c o n e e -1 v e s s e l a n a l y s i s a r e d i s c u s s e d

b e lo w .

5 . 3 .1 F r a c tu r e - M e c h a n ic s M odel

The f r a c t u r e - m e c h a n i c s (FM) m o d el i n OCA-P i s b a s e d o n l i n e a r e l a s t i c

f r a c t u r e m e c h a n ic s (LEFM) an d u s e s a s p e c i f i e d maximum v a lu e o f K_ t ol a

a c c o u n t f o r u p p e r - s h e l f b e h a v i o r . The s t r e s s i n t e n s i t y f a c t o r (K ^) i s

c a l c u l a t e d u s i n g s u p e r p o s i t i o n t e c h n i q u e s i n c o n j u n c t i o n w i t h i n f l u e n c e

c o e f f i c i e n t s t h a t w e re c a l c u l a t e d u s i n g f i n i t e - e l e m e n t t e c h n i q u e s . The

a p p l i c a t i o n o f t h i s p r o c e d u r e m ak es i t p o s s i b l e t o p e r fo rm a l a r g e

num ber o f d e t e r m i n i s t i c FM c a l c u l a t i o n s a t r e a s o n a b l e c o s t , a n e c e s s a r y

c o n d i t i o n f o r p e r f o r m in g t h e p r o b a b i l i s t i c a n a l y s i s .

The O conee-1 v e s s e l w as f a b r i c a t e d fro m s e c t i o n s o f p l a t e an d h a s b o th

a x i a l an d c i r c u m f e r e n t i a l w e ld s i n t h e b e l t l i n e r e g i o n , a s show n i n F ig ­

u r e 5 . 2 . S e v e re d o f t h e w e ld s h a v e r a t h e r h ig h c o n c e n t r a t i o n s o f c o p p e r

an d n i c k e l w h i l e t h e c o n c e n t r a t i o n o f c o p p e r i n t h e b a s e m a t e r i a l i s

5.6

A P P R O X

L O C A T I O N

O F

A C T I V E

F U E L

ZV2861 (Nozzle Belt) SA1526] Outlet

SA1494/ Nozzles Only

SA1135

C2197-2 (Inter­mediate Shell)

SA1229 - 61Z (ID) MF 25 - 39Z (OD)C3265-1 C3278-1 Upper Shell

SA1585

C2800-11 Lower Shell C2800-2J

o

WF112

122S34VA1 Dutchman

F ig u r e 5 . 2 . L o c a t io n and i d e n t i f i c a t i o n o f m a t e r i a l s u s e d i ni n f a b r i c a t i o n o f O conee-1 r e a c t o r p r e s s u r e v e s s e l ,

5.7

s i g n i f i c a n t l y lo w e r . F u r th e r m o r e , v a l u e s o f K j fo p ^ e e p a x i a l f l a w s a r e

much g r e a t e r t h a n f o r d e e p c i r c u m f e r e n t i a l f l a w s . T hus a s d i s c u s s e d i n

S e c t i o n 5 .4 an d A p p e n d ix D i n g r e a t e r d e t a i l , t h e f l a w s o f i n t e r e s t a r e

r e s t r i c t e d t o th e a x i a l l y o r i e n t e d w e ld s .

The l e n g t h o f f l a w s i n t h e a x i a l w e ld s w i t h d e p th s g r e a t e r t h a n mm

w as assu m ed t o b e 1 .8 m, w h ich i s a p p r o x im a te ly t h e h e i g h t o f a s h e l l

c o u r s e , an d t h e s h a p e w as a ssu m ed t o be s e m i e l l i p t i c a l ( t h i s f l a w i s

r e f e r r e d t o a s t h e 2-m f l a w ) . S in c e t h e e n d s o f t h i s f l a w a r e f i x e d ,

p r o p a g a t i o n w as ju d g e d o n t h e b a s i s o f t h e K r a t i o s (K _/K .. , K -/K .. ) a tI 1C 1 l a

t h e d e e p e s t p o i n t o f t h e f l a w .

S h a l lo w e r f l a w s w e re assu m ed to b e tw o -d im e n s io n a l ( te r m e d 2-D f l a w s ) ,

s i n c e lo n g s h s d lo w f l a w s a r e e s s e n t i a l l y tw o - d im e n s io n a l , and s h o r t f l a w s

t e n d t o g ro w on th e s u r f a c e t o becom e lo n g f l a w s ,^ a t l e a s t i n t h e a b s e n c e

o f c l a d d i n g . B e c a u se t h e e f f e c t o f c l a d d i n g on t h e s u r f a c e e x t e n s i o n o f

s h o r t f l a w s i s n o t known a t t h i s t im e , an y p o s s i b l e b e n e f i c i a l e f f e c t h a s

b e e n d i s c o u n t e d .

C la d d in g o n t h e i n n e r s u r f a c e o f PWR p r e s s u r e v e s s e l s w as i n c l u d e d i n

t h e OCA-P a n a l y s i s a s a d i s c r e t e r e g i o n t o t h e e x t e n t t h a t t h e th e rm e il

an d s t r e s s e f f e c t s w e re a c c o u n te d f o r . As m e n t io n e d a b o v e , t h e e f f e c t

o f c l a d d i n g o n t h e s u r f a c e e x t e n s i o n o f f i n i t e - l e n g t h f l a w s w as n o t c o n ­

s i d e r e d .

5.8

B e c a u se o f t h e d i f f e r e n c e i n t h e c o e f f i c i e n t o f th e r m a l e x p a n s io n

b e tw e e n th e c l a d d i n g a n d b a s e m a t e r i a l , t h e c a l c u l a t e d s t r e s s e s i n t h e

c l a d d i n g e x c e e d t h e y i e l d s t r e n g t h o f t h e c l a d d i n g by a n a p p r e c i a b l e

a m o u n t, and t h i s r e s u l t s i n a n o v e r e s t i m a t i o n o f t h e v a l u e s f o r th e

f l a w s , w h ic h w e re assu m ed t o t e r m i n a t e i n t h e c l a d d i n g o r e x te n d th ro u g h

t h e c l a d d i n g i n t o t h e b a s e m a t e r i a l . An a l t e r n a t i v e a p p ro a c h w ou ld be

t o l i m i t t h e s t r e s s i n t h e c l a d d i n g t o t h e y i e l d s t r e s s , b u t t h i s

u n d e r e s t im a te s b e c a u s e K . i s s e n s i t i v e t o t h e s t r a i n , w h ich i s n o t

l i m i t e d by t h e y i e l d i n g phen o m en o n . The d i f f e r e n c e i n b e tw e e n t h e s e

tw o e x t r e m e s i s n o t l a r g e * t h u s t h e c o n s e r v a t i v e e x tre m e w as s e l e c t e d .

M a t e r i a l p r o p e r t i e s r e q u i r e d f o r t h e f r a c t u r e - m e c h a n ic s a n a l y s i s i n c l u d e

t h e s t a t i c c r a c k i n i t i a t i o n an d a r r e s t to u g h n e s s v s i lu e s and

a n d t h e n i l - d u c t i l i t y r e f e r e n c e t e m p e r a tu r e (RTNDT). F o r t h e p ro b a ­

b i l i s t i c f r a c t u r e - m e c h a n i c s a n a l y s i s , m ean v e ilu e s o f t h e s e p a r a m e te r s

a r e r e q u i r e d , an d th e y w e re o b t a i n e d f o r t h e v e s s e l w e ld m a t e r i a l a s

f o l l o w s :

K jc = 1 .4 3 {36 .5 + 3 .0 8 4 exp [ 0 .0 3 6 (T - RTNDT + 5 6 ) ] } , MPa /m ( 5 .1 )

= 1 .2 5 {29 .5 + 1.344 exp [0 .0 2 6 1 (T - RTNDT + 89) ] } , MPa ( 5 .2 )

5w h e re t h e q u a n t i t y i n b r a c e s r e p r e s e n t s t h e ASME S e c t i o n XI lo w e r-b o u n d

to u g h n e s s v a lu e an d T i s t h e t e m p e r a tu r e a t t h e t i p o f t h e f la w i n °C.

T h ese e x p r e s s i o n s w e re o b t a i n e d by l e t t i n g t h e ASME lo w e r bound c u r v e s

r e p r e s e n t th e m ean v a l u e s m in u s tw o s t a n d a r d d e v i a t i o n s (2a) and by l e t ­

t i n g . = 0 .15 K . a n d a . „ . = 0 .1 0 K_ .( K j^ ) I c ( K j^ ) l a

5.9

I n m any o a s e s , i f c r a c k a r r e s t t a k e s p l a c e , i t m u s t do s o a t u p p e r - s h e l f

t e m p e r a t u r e s , t h a t I s , a t t e m p e r a t u r e s t h a t , u n d e r s t a t i c l o a d i n g c o n d i ­

t i o n s , r e s u l t I n d u c t i l e r a t h e r th a n b r i t t l e b e h a v io r o f t h e m a t e r i a l .

C ra c k a r r e s t u n d e r t h e s e c o n d i t i o n s I s n o t w e l l u n d e r s to o d b u t h a s b e e n

I n c lu d e d I n a n a p p r o x im a te m an n er by s p e c i f y i n g a maximum v a lu e o f

t h a t c o r r e s p o n d s t o t h e u p p e r p o r t i o n o f a n u p p e r - s h e l f t e a r i n g r e s i s ­

t a n c e c u r v e . As I l l u s t r a t e d I n F ig u r e 5 . 3 , w h ic h I s a p l o t o f K v s

c r a c k d e p th ( a ) an d t a n p e r a t u r e (T ) a t a s p e c i f i c t im e I n a t r a n s i e n t .

I f t h e l o a d l i n e (K_ v s a , T) I n t e r s e c t s t h e K . c u r v e a t K_ <X x a Xa

(K ia)m ax» u p p e r - s h e l f t o n p e r a t u r e s a r e n o t e n c o u n te r e d . I f , on t h e

o t h e r h a n d , t h e l o a d l i n e m i s s e s t h e r i s i n g p o r t i o n o f t h e c u r v e an d

t h e n d e c r e a s e s , a s I t d o e s f o r scmie t r a n s i e n t s , t h e r e I s , a c c o r d in g t o

t h e m o d e l , a p o s s i b i l i t y o f c r a c k a r r e s t a t u p p e r - s h e l f t e m p e r a t u r e s .

The t e a r i n g r e s i s t a n c e c u r v e s e l e c t e d f o r t h i s s t u d y r e p r e s e n t s a

s p e c i f i c h ig h c o p p e r , l o w - u p p e r - s h e l f w e ld m a t e r i a l t h a t had b e e n I r r a -

19 2d l a t e d t o a f l u e n c e o f '^"1.2 x 10 n e u t r o n s /c m a t a t e m p e r a tu r e o f

''^300°C an d t e s t e d a t 2 0 0 °C .^ The u p p e r , n e a r l y f l a t p o r t i o n o f t h i s

c u r v e c o r r e s p o n d s t o a K j v a lu e o f " ^ 2 0 MPa an d t h i s v a lu e w as u s e d

f o r (K - ) i K t w as o b t a i n e d u s i n g t h e r e l a t i o n l a max J

K j = / J E ( 5 .3 )

w h e re J = s t r a i n e n e rg y r e l e a s e r a t e

E = Y o u n g 's m o d u lu s

T h e t e a r i n g r e s i s t a n c e o f PWR v e s s e l m a t e r i a l s t e n d s t o d e c r e a s e w i th

I n c r e a s i n g t e m p e r a tu r e and f l u e n c e , £Uid t h u s t h e e f f e c t s o f t e m p e r a tu r e and

5.10

la ^max

arrest

mat' 1

ar res t

T,

a , T

F ig u r e 5 . 3 . I l l u s t r a t i o n o f a m e th o d o f s e l e c t i n g (K )XSl lUcLX

5.11

f l u e n c e t e n d t o c o m p e n s a te f o r e a c h o t h e r th ro u g h t h e w a l l o f t h e

v e s s e l . B e c a u se o f t h i s an d t h e v e r y a p p ro x im a te n a t u r e o f t h e t r e a t ­

m en t o f a r r e s t o n t h e u p p e r s h e l f , no a t t e m p t w as m ade t o a c c o u n t m ore

a c c u r a t e l y f o r t h e e f f e c t s o f t e m p e r a t u r e an d f l u e n c e o n (K_ )l a max

The n i l - d u c t i l i t y r e f e r e n c e t e m p e r a t u r e (RTNDT) i s e q u a l t o t h e sum o f

a n i n i t i a l ( z e r o f l u e n c e ) v a lu e (RTNDT ) an d a n i n c r e a s e d u e t o r a d i a -o

t i o n dam age (ARTNDT)j t h a t i s ,

RTNDT = RTNDT + ARTNDT ( 5 .4 )o

The c o r r e l a t i o n f o r ARTNDT u s e d i n t h e s e s t u d i e s w as r e c e n t l y p ro p o s e d

7by R a n d a l l an d i s

ARTNDT = 0 .5 6 [ - 1 0 + 4 70 Cu + 350 Cu N i] (F x 1 0 " ' '^ ) ° ’ ^'^ , °C ( 5 .5 )

o r

- 19^ 0.194ARTNDT = 0 .5 6 [2 8 3 (F x 1 0 " ^ ) ^ - 4 8 ] , °C ( 5 .6 )

w h ic h e v e r i s s m e i l le r , w h e re

Cu, N i = c o n c e n t r a t i o n s o f c o p p e r an d n i c k e l , w t $ ,

F = f a s t - n e u t r o n f l u e n c e ( n e u t r o n e n e rg y > 1 MeV), n e u t r o n s /c m2

T he a t t e n u a t i o n o f t h e f l u e n c e th r o u g h t h e w a d i o f t h e v e s s e l i s a p p ro x ­

im a te d w i th

F , F e-O-OO S'' “ ( 5 .7 )o

w h e re F i s t h e f l u e n c e a t t h e i n n e r s u r f a c e o f t h e v e s s e l an d a i s t h e o

c r a c k d e p th i n m i l l i m e t e r s . The s p e c i f i c v a lu e o f t h e c o e f f i c i e n t i n

t h e e x p o n e n t a c c o u n t s t o som e e x t e n t f o r t h e e f f e c t o f s p a c e - w is e s p e c -

7t r a l c h a n g e s o n r a d i a t i o n d am ag e .

5.12

I f t h e a s s u m p t io n i s m ade t h a t a s h o r t a n d s h a l lo w s u r f a c e f la w c a n

e x te n d o n th e s u r f a c e th ro u g h t h e c l a d d i n g t o becom e a lo n g f la w (a n d

t h i s a s s u m p t io n i s made f o r t h e s e s t u d i e s ) , t h e n i t m u s t b e assu m ed t h a t

u n d e r t h e p r o p e r c i r c u m s ta n c e s a v e r y sh e illo w f la w t h a t i n i t i a l l y

r e s i d e s e n t i r e l y w i t h i n t h e c l a d d i n g c a n p r o p a g a te r a d i a l l y . U n fo r­

t u n a t e l y , t h e f r a c t u r e - t o u g h n e s s p r o p e r t i e s o f t h e c l a d d in g m a t e r i a l a r e

v e r y u n c e r t a i n , an d t h e few e x p e r im e n ta l d a t a t h a t a r e a v a i l a b l e i n d i ­

c a t e a r a d i a t i o n - i n d u c e d r e d u c t i o n i n f r a c t u r e to u g h n e s s s i m i l a r t o t h a t

f o r th e b a s e m a t e r i a l . As a n e x p e d ie n c y , w h ich may o r may n o t be co n ­

s e r v a t i v e , i t w as assu m ed t h a t t h e c l a d d i n g h a s t h e sam e f r a c t u r e -

to u g h n e s s p r o p e r t i e s a s t h e b a s e m a t e r i a l (E q s . 5 . 1 , 5 . 2 , 5 . 5 , an d 5 . 6 ) .

I n t h e OCA-P a n a l y s i s , a s s u m p t io n s r e g a r d i n g t h e f r a c t u r e b e h a v io r o f th e

c l a d d i n g i n f l u e n c e o n ly t h e i n i t i a t i o n o f v e r y s h a l lo w f la w s t h a t i n i ­

t i a l l y t e r m i n a t e i n t h e c l a d d i n g . U nder som e c i r c u m s t a n c e s , i n c l u d i n g

t h e ab o v e a s s u m p t io n r e g a r d i n g t h e f r a c t u r e to u g h n e s s o f t h e c l a d d i n g ,

t h e s e s h a l lo w f l a w s w i l l i n i t i a t e an d r e s u l t i n v e s s e l f a i l u r e . T h e re ­

f o r e i t w as n e c e s s a r y t o i n c l u d e t h e f r a c t u r e p r o p e r t i e s o f t h e c l a d ­

d in g .

The d e t e r m i n i s t i c f r a c t u r e - m e c h a n i c s m odel d e s c r i b e d a b o v e i s u s e d i n

OCA-P t o p r e d i c t t h e b e h a v io r o f a f la w d u r in g a s p e c i f i e d OCA a t a

s p e c i f i e d t im e i n t h e l i f e o f t h e v e s s e l , an d t h e c a l c u l a t e d b e h a v io r

c a n b e i l l u s t r a t e d w i th a s e t o f c r i t i c a l - c r a c k - d e p t h c u r v e s s i m i l a r t o

t h o s e show n i n F ig u r e 5 . 4 . The f i g u r e c o n s i s t s o f a p l o t o f c r a c k

d e p th s c o r r e s p o n d in g t o v a r i o u s e v e n t s a n d c o n d i t i o n s a s a f u n c t i o n o f

t h e t im e i n t h e t r a n s i e n t a t w h ic h t h e e v e n t s o r c o n d i t i o n s t a k e p l a c e o r

5.13

e x i s t . F ig u r e 5 .4 i n c l u d e s ( f o r 2-D f l a w s o n ly ) t h e l o c u s o f p o i n t s f o r

K j = ( c r a c k - i n i t i a t i o n c u r v e ) , ( c r a c k - a r r e s t c u r v e ) , K j =s

(K ) (warm p r e s t r e s s c u r v e w i t h = 0 ) , an d = c o n s t a n t ( i s o K_X l Qo 2 X X X

c u r v e s ) . F o r t im e s l e s s t h a n t h o s e i n d i c a t e d by t h e WPS c u r v e , c r a c k

i n i t i a t i o n w i l l t a k e p l a c e , b u t f o r g r e a t e r t im e s i n i t i a t i o n w i l l n o t

t a k e p l a c e u n l e s s p e r h a p s t h e r e i s a p e r t u r b a t i o n i n t h a t n e g a te s t h e

r e q u i s i t e c o n d i t i o n s f o r WPS.

The d a s h e d l i n e s i n F ig u r e 5 .4 i n d i c a t e t h e b e h a v io r o f tw o i n i t i a l l y

s h a l lo w f l a w s , i g n o r i n g t h e e f f e c t s o f WPS. The d e e p e r f la w w ou ld i n i ­

t i a t e a t a t im e o f 42 m in i n t o t h e t r a n s i e n t an d w o u ld e x te n d th ro u g h

t h e w a l l w i th o u t a r r e s t i n g . The o t h e r f l a w w o u ld i n i t i a t e a t a n e a r l i e r

t i m e , w o u ld a r r e s t a t a p o i n t 36$ o f t h e way th r o u g h t h e w a l l , an d th e n

w o u ld r e i n i t i a t e a t a t im e o f '^^8 m in an d p e n e t r a t e t h e w a l l . E a r l i e r

i n t h e l i f e o f t h e v e s s e l t h e te n d e n c y f o r c o m p le te p e n e t r a t i o n o f t h e

w a l l i s l e s s .

5 . 3 . 2 S t r e s s A n a ly s i s M odel

U s in g t h e s u p e r p o s i t i o n t e c h n iq u e i n c o m b in a t io n w i t h i n f l u e n c e c o e f f i ­

c i e n t s , t h e s t r e s s e s r e q u i r e d f o r t h e c a l c u l a t i o n o f a r e t h o s e a t t h e

c r a c k p la n e c a l c u l a t e d i n t h e a b s e n c e o f t h e c r a c k a n d w i th no v a r i a t i o n

i n th e d i r e c t i o n o f t h e l e n g t h o f t h e c r a c k . F o r t h e O c o n e e -1 a n a l y s i s ,

i t w as assu m ed t h a t t h e r e w as no a z im u th a l v a r i a t i o n a s w e l l , an d th u s

t h e o n e - d im e n s io n a l s t r e s s a n a l y s i s m odel i n c o r p o r a t e d i n OCA-P w as a d e ­

q u a t e .

5.14

CRITICAL CRACK DEPTH CURVES FOR TEMP - ISO + 400 EXP(-0.1SOT) iRTNOTO - 40.0 OEGF XCU - 0.35 FO - 0.2SE19 PR- 1.00 KSI LONGIT

o>d

WP S(Dd

2CX7(OdFLAWP A T H

3 «I S O K

.oo 100

d

C ld

dm

o IX noso X 70 X X0 10 X X X TIME(MINUTES)

F ig u r e 5 * 4 . C r i t i c a l - c r a c k - d e p t h c u r v e s f o r a t y p i c a l p o s t u l a t e d o v e r c o o l i n g a c c i d e n t .

5.15

M a t e r i a l p r o p e r t i e s r e q u i r e d f o r t h e s t r e s s a n a l y s i s i n c l u d e d t h e c o e f ­

f i c i e n t o f th e r m a l e x p a n s io n ( c t) , Y oung’ s m o d u lu s ( E ) , and P o i s s o n ’ s

r a t i o ( v ) . A lth o u g h t h e s e p r o p e r t i e s h a v e som e t e m p e r a tu r e d e p e n d e n c e ,O

i t w as d e te r m in e d t h a t t h e u s e o f a p p r o p r i a t e a v e r a g e v a l u e s r e s u l t s i n

a n e r r o r i n t h e c a l c u l a t e d v a l u e o f o f l e s s t h a n 1 0 $ , T h u s , a v e r a g e

v a l u e s w e re u s e d b a s e d o n t h e d a t a i n R e fe r e n c e 9* The v a l u e s u s e d f o r

t h e O conee-1 a n a l y s i s a r e a s f o l l o w s :

P r o p e r ty B ase M a t e r i a l C la d d in g

a , °C "'' 1.M5 X 10"^ 1 .7 9 x 10"^

E , MPa 1 .9 3 X 10^ 1 .8 6 x 10^

V 0 .3 0 0 .3 0

5 . 3 . 3 T h erm a l A n a ly s i s M odel

T e m p e ra tu re s i n t h e w a l l o f t h e v e s s e l a r e r e q u i r e d f o r tw o p u r p o s e s : t o

c a l c u l a t e t h e th e r m a l s t r e s s e s an d t o c a l c u l a t e t h e f r a c t u r e t o u g h n e s s .

T he t e m p e r a t u r e s r e q u i r e d f o r d e t e r m in in g t h e f r a c t u r e to u g h n e s s a r e

t h o s e i n t h e p l a n e o f t h e f l a w , w h i l e t h o s e u s e d i n t h e o n e - d im e n s io n a l

a n a l y s i s o f t h e th e r m a l s t r e s s e s m u s t r e p r e s e n t som e ty p e o f a v e r a g e

d i s t r i b u t i o n th r o u g h t h e w a l l . The th e r m a l s t r e s s e s i n t h e v i c i n i t y o f

t h e c r a c k p l a n e a r e m ore s e n s i t i v e t o t h e r a d i a l t e m p e r a t u r e d i s t r i b u ­

t i o n a t t h e c r a c k p l a n e th a n e l s e w h e r e . S in c e t h e s e t e m p e r a t u r e s a r e

t h e ssune a s t h o s e n e e d e d f o r t h e f r a c t u r e - t o u g h n e s s d e t e r m i n a t i o n s , an d

s i n c e o n ly o n e s e t o f t e m p e r a t u r e s w as t o be u s e d f o r b o th t h e s t r e s s

a n d to u g h n e s s c a l c u l a t i o n s , t h e l o c a l t e m p e r a t u r e s w o u ld b e t h e c h o i c e .

T h e se p a r t i c u l a r t e m p e r a t u r e s w e re n o t a v a i l a b l e , b u t f o r t u n a t e l y t h e

5.16

r e s u l t s o f t h e t h e n n a l - h y d r a u l l c a n a l y s i s i n d i c a t e d t h a t f o r t h e t r a n ­

s i e n t s o f I n t e r e s t t h e r e w as n o t much a z im u th a l v a r i a t i o n I n t h e dow nco­

m er c o o l a n t t a i p e r a t u r e . T h u s , t h e t im e - d e p e n d e n t t e m p e r a tu r e d i s t r i b u ­

t i o n s I n t h e w a l l o f t h e v e s s e l w e re c a l c u l a t e d w i th t h e o n e - d lm e n s lo n a l

t h e r m a l - a n a l y s l s m o d e l I n OCA-P u s i n g a v e r a g e dow ncom er c o o l a n t te m p e ra ­

t u r e s an d h e a t t r a n s f e r c o e f f i c i e n t s .

M a t e r i a l p r o p e r t i e s r e q u i r e d f o r t h e th e r m a l a n a l y s i s I n c lu d e th e t h e r ­

m al c o n d u c t i v i t y ( k ) , s p e c i f i c h e a t ( c ^ ) , and d e n s i t y (p) o f th e v e s s e l

m a t e r i a l . The v a l u e s u s e d a r e a s f o l l o w s :

Property Base Material Cladding k , W /m-°C M l.5 1 7 .3

c , J /k g * ° C 502 502P

P , Kg/m^ 7830 78 3 0

5 .3 .M P r o b a b i l i s t i c A n a ly s i s M odel

The OCA-P p r o b a b i l i s t i c m o d e l , w h ic h I s s i m i l a r t o t h a t d e v e lo p e d by

G am ble an d S t r o s n l d e r , ^ ^ I s b a s e d o n M onte C a r lo t e c h n i q u e s ; t h a t I s , a

l a r g e num ber o f v e s s e l s I s g e n e r a t e d , and e a c h v e s s e l I s th e n s u b j e c t e d

t o a f r a c t u r e - m e c h a n i c s a n a l y s i s t o d e te r m in e w h e th e r t h e v e s s e l w i l l

f a l l . E ach v e s s e l I s d e f in e d by ra n d o m ly s e l e c t e d v a l u e s o f s e v e r a l

p a r a m e te r s t h a t a r e ju d g e d t o h a v e s i g n i f i c a n t u n c e r t a i n t i e s a s s o c i a t e d

w i th th em . The c a l c u l a t e d p r o b a b i l i t y o f v e s s e l f a i l u r e I s s im p ly th e

num ber o f v e s s e l s t h a t f a l l d i v i d e d by t h e t o t a l num ber o f v e s s e l s g en ­

e r a t e d . I t c o n s t i t u t e s a c o n d i t i o n a l p r o b a b i l i t y o f f a i l u r e , P ( f 1e ) ,

b e c a u s e t h e a s s u m p t io n I s m ade t h a t t h e OCA ( e v e n t ) t a k e s p l a c e . A

5.17

l o g i c d ia g ra m s u m m a r iz in g t h e v a r i o u s s t e p s i n t h e OCA-P p r o b a b i l i s t i c

a n a l y s i s i s show n i n F ig u r e 5 . 5 .

The p a r a m e te r s s i m u la te d f o r t h e O conee-1 a n a l y s i s a r e c r a c k d e p th ( a ) ,

F , RTNDT, Cu, N i , K,. , an d K,. . N orm al d i s t r i b u t i o n s w e re assu m ed f o rO J J W

a l l o f t h e s e p a r a m e te r s e x c e p t t h e c r a c k d e p t h ; t h e s t a n d a r d d e v i a t i o n s

an d t r u n c a t i o n v a l u e s u s e d i n t h e a n a l y s i s a r e i n c l u d e d i n T a b le 5 . 1 .

The p r o b a b i l i t y o f h a v in g a f l a w i n a s p e c i f i c w e ld w i t h a d e p th i n a

s p e c i f i c r a n g e o f c r a c k d e p t h s Aa^ i s g iv e n by

P (A a ,) = NV / f ( a ) B ( a ) d a ( 5 .8 )

w h e re

N = f l a w s o f a l l d e p t h s p e r u n i t v o lu m e o f t h e s p e c i f i c w e ld

V = v o lum e o f t h e s p e c i f i c w e ld

f ( a ) = f l a w - d e p t h d e n s i t y f u n c t i o n

B (a ) = p r o b a b i l i t y o f n o n d e t e c t io n

The p a r a m e te r s N an d f ( a ) p e r t a i n t o v e s s e l c o n d i t i o n s p r i o r t o p r e s e r ­

v i c e i n s p e c t i o n an d r e p a i r , an d B (a ) i s d e r iv e d o n t h e b a s i s o f r e p a i r ­

i n g o r o th e r w is e d i s p o s i n g o f a l l d e t e c t e d f l a w s .

The v a lu e o f N an d t h e f u n c t i o n s f ( a ) an d B (a ) a r e n o t w e l l known

b e c a u s e m o s t o f t h e a v a i l a b l e i n s p e c t i o n d a t a do n o t p e r t a i n t o s u r f a c e

f l a w s t h a t e x te n d i n t o an d th r o u g h t h e c l a d d i n g o f a PWR p r e s s u r e

v e s s e l . F o r t h e O co n ee-1 a n a l y s i s , t h e f u n c t i o n s f ( a ) an d B (a ) w e re

t h o s e s u g g e s te d i n t h e M a r s h a l l R e p o r t^ ^ and a r e a s f o l l o w s :

5.18

O R N L - D W G 8 4 - 4 1 7 4 E T D

S I M U L A T E K E R R O R

A D V A N C E T I M E

N O

N O

Y E SY E S

Y E S

N O

C A L C U L A T E R T N D T

K / K ,

Y E S

N O

N U M B E R O F ^ C R A C K D E P T H S

E X H A U S T E D ’N O

[ y e s

N O

[ y e s

P E R F O R M E D E N O U G H

_ T R I A L S ’

P L A S T I CI N S T A B I L I T Y ’

"- IS THE T R A N S I E N T

OVER?

C A L C U L A T E R T N D T

S I M U L A T E K

A D D O N E T O N U M B E R O F F A I L U R E S

A D D O N E T O N U M B E R O F N O N F A I L U R E S

C A L C U L A T E C O N D I T I O N A L P R O B A B I L I T Y O F F A I L U R E

A D O O N E T O N U M B E R O F T R I A L S

S E T C R A C K D E P T H T O A R R E S T D E P T H

A D V A N C E C R A C K D E P T H

D E F I N E T R A N S I E N T A N D

C A L C U L A T E T v s ( a / w , t )K v s ( a / w . t )

C A L C U L A T E K | ^

= f ( R T N D T ( a / w l .

T l a / w . t )

K , E R R O R )

S E L E C T M E A N V A L U E S O F

F L U E N C EN I C K E LC O P P E RR T N D T

C R E A T E A V E S S E L B Y S I M U L A T I N G

C R A C K D E P T H A R T N D T E R R O R W E L D

F L U E N C EN I C K E LC O P P E RR T N D T ^

F ig u r e 5 . 5 . OCA-P p ro g ram l o g i c .

5.19

Table 5.1. Parameters simulated in OCA-P

P aram eterS tan d ard *D e v ia tio n

( a )T ru n c a tio n

F luence (F) 0 .3 y (F ) F = 0

Copper 0.025$ —

N ick e l 0 .0 —

RTNDTo9°C»« « *

ARTNDT 13°C»« » *

KtIc 0 .1 5 y (K jc ) ±3a

Kt— la ------------------ 0 .1 0 ±30

•N o rm al d i s t r i b u t i o n u s e d f o r e a c h p aram e­t e r .

r 2 2 11/2(RTNDT) = [^(RTNDT^) ^(ARTNDT^ '

t r u n c a t e d a t ± 3 a .

5.20

f(a) = 0.16 ® (5.9)

B (a ) = 0 .0 0 5 + 0 .9 9 5 ^ ( 5 .1 0 )

w h e re

a = c r a c k d e p t h , mm

00

/ f ( a ) d a = 1

F o r t h e O conee-1 v e s s e l t h e p r o b a b i l i t y o f n o n d e t e c t io n , B ( a ) , s h o u ld

p r o b a b ly b e s e t e q u a l t o u n i t y , in d e p e n d e n t o f a , b e c a u s e i t i s n o t

l i k e l y t h a t a r e l i a b l e i n s p e c t i o n w as m ade f o r f l a w s i n an d e x te n d in g a

s h o r t d i s t a n c e b ey o n d t h e c l a d d i n g . F u r th e r m o r e , i t i s n o t l i k e l y t h a t

a n y d e t e c t e d f l a w s o f t h i s ty p e w e re r e p a i r e d . E ven s o , E q . 5 .1 was

u s e d i n t h e O conee-1 a n a l y s i s . I f B (a ) = 1 w e re u s e d i n s t e a d , P (F |E)

w o u ld b e a b o u t tw ic e a s m uch . T hus t h e r e s u l t s o f t h i s s tu d y c a n be

i n t e r p r e t e d a c c o r d i n g l y .

A f t e r O conee-1 h ad b e e n i n o p e r a t i o n f o r '^lO y e a r s , an i n - s e r v i c e

i n s p e c t i o n o f t h e r e a c t o r p r e s s u r e v e s s e l w as p e r fo rm e d . No f l a w s w e re

fo u n d } h o w e v e r, t h e s i g n i f i c a n c e o f t h i s i n s p e c t i o n i n te rm s o f d i f f e r ­

e n c e s b e tw e e n th e assu m ed a n d a c t u a l f l a w - d e p th d e n s i t y f u n c t i o n and

f l a w d e n s i t y was n o t a p p a r e n t a t t h e t im e o f t h i s w r i t i n g .

The v a lu e o f N u s e d i n t h e O co n ee-1 a n a l y s i s w as 1 f la w /m o f w e ld

m a t e r i a l , an d i t w as assu m ed t h a t a l l f l a w s w e re i n n e r - s u r f a c e f la w s

n o rm a l t o t h e s u r f a c e an d o r i e n t e d i n t h e l e n g t h - d i r e c t i o n o f t h e w e ld .

5.21

T h is v a l u e o f t h e f l a w d e n s i t y a g r e e s w i t h t h a t s u g g e s te d i n t h e

M a r s h a l l R e p o r t , b u t t h e u n c e r t a i n t y i s c o n s i d e r e d t o b e v e r y l a r g e ( a iv

1 0 ^ ).

The v o lu m e (V) o f a w e ld u s e d f o r c a l c u l a t i n g t h e num ber o f s u r f a c e

f l a w s i n a w e ld w as t h e t o t a l v o lu m e o f t h a t p o r t i o n o f t h e w e ld t h a t

w as n e a r l y w i t h i n t h e a x i a l c o n f i n e s c o r r e s p o n d in g t o t h e a c t i v e l e n g t h

o f t h e c o r e .

As m e n t io n e d a b o v e , t h e c a l c u l a t e d p r o b a b i l i t y o f v e s s e l f a i l u r e f o r

t h i s s tu d y i s t h e num ber o f s im u la te d v e s s e l s c a l c u l a t e d t o f a i l d i v i d e d

by t h e t o t a l num ber o f v e s s e l s s i m u la te d o r o t h e r w is e a c c o u n te d f o r .

T h u s ,w

P ( F |E ) = E - j 7 r ^ V N / * f ( a ) B ( a ) d a ( 5 .1 1 )j v j J •()

w h e re

= num ber o f v e s s e l s w i t h a f l a w i n t h e j t h w e ld t h a t f a i l

= num ber o f v e s s e l s s i m u la te d w i t h a f la w i n t h e j t h w e ld

V j = v o lu m e o f j t h w e ld

The i n t e g r a l i n E q , 5 .1 1 a c c o u n t s f o r t h e v e s s e l s t h a t h a v e no f l a w s

w h a ts o e v e r , an d e a c h te rm i n E q . 5 .1 1 r e p r e s e n t s t h e c o n t r i b u t i o n t o

P ( F |E ) o f e a c h w e ld .

F o r v e r y s m a l l v a l u e s o f P ( F |E ) , t h e v a l u e o f r e q u i r e d t o a c h ie v e

r e a s o n a b l e a c c u r a c y b eco m es q u i t e l a r g e . U nder s a n e c i r c u m s ta n c e s t h e

5.22

v a l u e o f N’ y j c a n b e r e d u c e d by u s i n g s t r a t i f i e d s a m p lin g o f one o r m ore

o f t h e p a r a m e te r s s i m u la t e d . T h is w as d o n e f o r t h e f la w d e p th , a s s u m in g

a u n i fo rm d i s t r i b u t i o n o f d e p t h s . T h is p r o c e d u r e a l lo w s a m ore f r e q u e n t

s a m p l in g o f t h e l e s s p r o b a b le d e e p f l a w s , w h ic h , f o r l o w - p r o b a b i l i t y

t r a n s i e n t s t h a t a r e c h a r a c t e r i z e d by h ig h p r e s s u r e an d a m ild th e rm a l

s h o c k , a r e r e s p o n s i b l e f o r m o s t o f t h e i n i t i a t i o n e v e n t s t h a t l e a d t o

f a i l u r e . The r e s u l t s a r e t h e n w e ig h te d by t h e a c t u a l f l a w - d e p th d e n s i t y

t o o b t a i n

P (F |E ) = L E

w h e re

/ f ( a ) B ( a ) d a

w

j" f ( a ) B ( a ) d a

r R 1NV / f ( a ) B ( a ) d a

0

* * * fij “ num ber o f v e s s e l s t h a t f a i l w i th a f la w i n t h e j t h w e ld

w i t h d e p th i n Aa^

= num ber o f v e s s e l s s i m u la te d w i th a f la w i n t h e j t h w e ld

w i t h d e p th i n Aa^

A d e t e r m i n i s t i c a n a l y s i s i s made f o r e a c h o f t h e s im u la te d v e s s e l s t o

d e te r m in e i f f a i l u r e w i l l o c c u r d u r i n g a p a r t i c u l a r t r a n s i e n t a t a

s p e c i f i e d t im e i n t h e l i f e o f t h e p l a n t . The c r i t e r i o n by w h ich f a i l u r e

i s ju d g e d i s a s f o l l o w s ; i f , f o l l o w i n g a n i n i t i a t i o n e v e n t , r e m a in s

g r e a t e r t h a n u p t o o r b ey o n d t h e p o i n t a t w h ich p l a s t i c i n s t a b i l i t y

o c c u r s i n t h e r e m a in in g l i g a m e n t , f a i l u r e i s a s su m e d . The o n s e t o f

p l a s t i c i n s t a b i l i t y i s e v a lu a t e d o n t h e b a s i s o f a c h ie v in g a n a v e ra g e

p r e s s u r e s t r e s s i n t h e r e m a in in g l i g a m e n t e q u a l t o t h e f lo w s t r e s s . The

f lo w s t r e s s i s a ssu m ed t o be i n d e p e n d e n t o f t e m p e r a tu r e and f l u e n c e and

i s s p e c i f i e d a s 550 MPa.

5.23

T he num ber o f v e s s e l s t h a t m u s t b e s im u la te d d e p e n d s u p o n t h e a c c u r a c y

r e q u i r e d f o r t h e c a l c u l a t e d v a l u e o f P ( F |E ) , an d a s s m a l l a num ber a s

p r a c t i c a l I s u s e d t o m in im iz e ccm ip u te r c o s t s . The minimum num ber o f

s i m u la t e d v e s s e l s r e q u i r e d t o s a t i s f y a s p e c i f i e d a c c u r a c y I s e s t i m a t e d

12b y a p p l y i n g t h e c e n t r a l l i m i t th e o re m ,

f y l n g a 95$ c o n f id e n c e l e v e l y i e l d s

U s in g t h i s a p p r o a c h an d s p e c l -

P ( F |E ) j = P j NV^y* f ( a ) B ( a ) d a ± 1 .9 6 ( 5 .1 3 )

w h e re

P ( F |E ) j = t r u e v a l u e o f t h e c o n d i t i o n a l p r o b a b i l i t y o f v e s s e l f a i l u r e

f o r t h o s e v e s s e l s h a v in g f l a w s I n t h e j t h w e ld o n ly

= o n e s t a n d a r d d e v i a t i o n

N*P = —

j N»v j

F o r t h e d i r e c t a p p ro a c h ( n o t u s i n g s t r a t i f i e d s a m p l in g ) ,

N»vJ

1/2NVj /* f ( a ) B ( a ) d a'/

( 5 .1 4 )

When s t r a t i f i e d s a m p l in g I s u s e d ,

■/ f ( a ) B ( a ) d a

Vf

i/f ( a ) B ( a ) d a

w h e re

N'

I j ■ N*mv l j

N'v l j

1/2( 5 .1 5 )

NVj / * f ( a ) B ( a ) d a

‘I

5.24

The v a l u e o f a c o r r e s p o n d in g t o a l l o f t h e v e s s e l s s im u la te d i s

^ p ( f | e ) ” ( 5. 16) J

an d t h e e r r o r , a s s o c i a t e d w i t h t h e j t h w e ld i s

_ ( 5 .1 7 )j " ^

P j NV i f f ( a ) B ( a ) d a■/0

The t o t a l e r r o r , e , c o n s i d e r i n g a l l w e ld s o f i n t e r e s t i s

£ 1 .9 6 g p ( p |E ) ( 5 ,1 8 )

2 ^ P . NV. / f ( a ) B ( a ) d a3 J jy

0T h re e s p e c i f i c c r i t e r i a w e re u s e d i n s e l e c t i n g t h e num ber o f v e s s e l s t o

b e s i m u la t e d :

<’ > ' “ ' v j W ' 5 0 0 .0 0 0

<2) < " V j > m l n ' ’ “ -O"'’

(3 ) e , = 10*

The a p p l i c a t i o n o f t h e s e c r i t e r i a i n te rm s o f £ j v s P j i s show n i n F ig ­

u r e 5 .6 f o r t h e d i r e c t ( n o n s t r a t i f i e d ) s a m p l in g m e th o d .

f ( a ) B ( a ) d a v a r i e s fro m 0 .6 x 10 to

- 2 ® I2 .3 X 10 . T h u s , w i t h i n a f a c t o r o f a b o u t 2 , P ( F |E ) j i s tw o o r d e r s o f

m a g n itu d e l e s s t h a n P j , an d t h e i n f o r m a t i o n i n F ig u r e 5 .6 c a n be i n t e r ­

p r e t e d a c c o r d i n g l y . F o r i n s t a n c e , s u p p o s e (1 ) t h e r e i s a n eed t o c a l c u l a t e

v a l u e s o f P (F |e ) a s lo w a s 3 x 10“ "^, ( 2 ) t h e r e a r e t h r e e w e ld s o f c o n c e r n ,

an d (3 ) a c o r r e s p o n d in g v a lu e o f P ( f 1 e ) j i s 1 x 10“ "^. T h u s , P j ^ 1 x 10“ ^ ,

an d fro m th e c u r v e i n F ig u r e 5 . 6 , lii 8 0 $ . The . e r r o r i n P ( f | e ) w ould

b e a p p r o x im a te ly 8 0 $ / ✓J 2 5 0 $ .

5.25

0Od01

10

10

10

F ig u r e 5 . 6 . G ra p h ic i l l u s t r a t i o n o f t h e e r r o r i n P . , c o n s i s t e n t w i th t h e c r i t e r i a u s e d f o r e s t a b l i s h i n g th e ^ n u m b e r o f v e s s e l s s im u la te d

5.26

F o r t h e p u rp o s e o f e s t i m a t i n g t h e a b s o l u t e f r e q u e n c y o f v e s s e l f a i l u r e

o r i d e n t i f y i n g d o m in a n t t r a n s i e n t s , t h e m a g n itu d e o f t h e e r r o r s i n d i ­

c a t e d i n F ig u r e 5 .6 i s a c c e p t a b l e . H ow ever, f o r t h e s e n s i t i v i t y s t u ­

d i e s , l a r g e r v a l u e s o f w e re u s e d w h e re a p p r o p r i a t e t o r e d u c e th e

e r r o r .

5 .4 F la w - R e la te d D a ta f o r t h e O co n ee-1 R e a c to r Pr e s s u r e V e s s e l

As a l r e a d y m e n t io n e d , t h e a r e a s o f t h e v e s s e l o f p a r t i c u l a r c o n c e r n w i th

r e g a r d t o f l a w p r o p a g a t i o n a r e t h e o n e s t h a t a r e m o s t l i k e l y t o h av e

f l a w s an d r e l a t i v e l y h ig h v a l u e s o f F ^ , RTNDT^, Cu, and N i. The r e g io n

d i r e c t l y o p p o s i t e t h e a c t i v e p o r t i o n o f t h e c o r e i s e x p o s e d t o th e

h i g h e s t n e u t r o n f l u x e s , an d t h e a t t e n u a t i o n b ey o n d t h e a c t i v e l e n g t h o f

t h e c o r e i s v e r y s t e e p . T h u s , o n ly t h i s b e l t l i n e r e g i o n o f t h e v e s s e l

w as c o n s i d e r e d .

W i th in th e b e l t l i n e r e g i o n t h e c o n c e n t r a t i o n o f c o p p e r i s s i g n i f i c a n t l y

l e s s i n t h e b a s e m a t e r i a l t h a n i n t h e w e ld s , a s i n d i c a t e d by t h e d a t a i n

T a b le 5 .2 an d F ig u r e s 5 . 2 , 5 . 7 , an d 5 . 8 . P r e l im in a r y OCA-P c a l c u l a t i o n s

( s e e A p p e n d ix D) i n d i c a t e d t h a t b e c a u s e o f i t s lo w e r c o p p e r c o n c e n t r a ­

t i o n th e b a s e m a te r i s i l c o n t r i b u t e d r e l a t i v e l y l i t t l e t o v e s s e l f a i l u r e ,

a s s u m in g t h e sam e f l a w d e n s i t y i n b o th t h e b a s e m a t e r i a l and w e ld s .

T h e se p r e l i m i n a r y c a l c u l a t i o n s a l s o i n d i c a t e d t h a t w e ld s SA1073> 1 4 3 0 ,

an d 1 4 9 3 , e a c h o f w h ic h i s o r i e n t e d i n a n a x i a l d i r e c t i o n , c o n t r i b u t e d

f a r m ore t h a n a l l t h e o t h e r w e ld s . F u r th e r m o r e , t h e s t a g g e r e d a r r a n g e ­

m en t o f t h e s e s i x w e ld s ( tw o e a c h ) an d t h e r e l a t i v e l y low c o n c e n t r a t i o n

o f c o p p e r i n t h e b a s e m a t e r i a l t e n d t o p r e v e n t s u r f a c e e x t e n s i o n o f a

5.27

T able 5 .2 . M a te r ia l p r o p e r t ie s used i n th e LEFM a n a ly s i s o f th e Oconee-1 r e a c to r v e s s e l

ro00

M a te r ia l I d e n t i f i c a t io n ^C hem istry^^

(wt %)

N eutron F lu e n ce , In s id e S u rface

(n/cm )I n i t i a l ^ ^ ^

RTNDTr o

Weld o r Heat Number Type Cu Ni 5 EFPY 32 EFPT

Volume(m ^

AHR-54 SA508, 0L2 0.16 NA 1.97E18 (+16)

SA1135 C irc u m fe re n tia lweld

0 .25 0 .54 1.97E18 ( -7 )

02197 SA302B 0.15 NA 9.35E18 (+4)

SA1073 L o n g itu d in a lweld

0.31 0 .64 1.43E18 7.38E18 ( -7 ) 0.01

SA1229 C irc u m fe re n tia lweld

0.26 0.61 9.35E18 (-7 )

SA1493 L o n g itu d in a lweld

0 .29 0 .55 1.74E18 8.98E18 ( -7 ) 0 .04

03278-1 SA302B 0 .1 2 NA 1.23E19 (+4)

SA1585 C irc u m fe re n tia lweld

0.21 0 .59 1.23E19 (-7 )

02800-1 SA302B 0.11 NA 1.23E19 (+4)SA1430 L o n g itu d in a l

weld0 .29 0 .55 2.11E18 1.09E19 ( -7 ) 0 .04

•S o u rce : BAW-1436, Septem ber 1977.

• •C h em is try so u rc e : BAW-1511Pf O ctober 1980.

• • •E s tim a te d RTNDT v a lu e s so u rc e : BAW-10046A, Rev. 1 , March 1976.

NA — Not a v a i l a b le .

FLUENCE NORMALIZED

NOZZLE VESSEL

INLET NOZZLE

TO PEAK FLUENCE LOCATION 12" —

19" SA-I>I30 WELD22" SA-1073 WELD

.77.70

COREREGION

t~cF ig u r e 5 . 7 . L o n g i t u d in a l w e ld l o c a t i o n s t o a z im u th a l f l u e n c e

p r o f i l e . 13

5.29

90

Y

II BO

Z

I270

«I

360

li.V. FLANGE

MATING

S U R F A C E

223.5“ REF.C.F. NOZZLE

O U TOUT

56.9

166.719'433.992'

SA-122920.53'202.971SAI493

471.105'

63.3' SA-I5B5162.186" -

SA-1430428.554'

536.4'

F i g u r e 5 . 8 D e v e l o p e d v i e w o f i n n e r s u r f a c e o f O c o n e e - 1r e a c t o r v e s s e l s h o w i n g w e l d l o c a t i o n s . 1 3

5.30

f l a w b ey o n d t h e e n d s o f t h e w e ld s . T h u s , t h e o n ly r e g i o n s o f t h e v e s s e l

c o n s i d e r e d i n t h e f i n a l a n a l y s i s w e re t h e s e s i x w e ld s .

V a lu e s o f Cu, N i, F , RTNDT , an d V f o r t h e s i x w e ld s o f c o n c e r n a r eo o

i n c l u d e d i n T a b le 5 . 2 . The f l u e n c e r a t e , F/EFPY , w as assu m ed t o be co n ­

s t a n t b e f o r e and a f t e r 5 EFPY, a t w h ic h t im e th e f l u e n c e r a t e a t O conee was

r e d u c e d . The w e ld v o lu m e s a r e b a s e d o n t h e t o t a l l e n g t h s o f t h e w e ld s

b e c a u s e , a s show n i n F ig u r e 5 . 2 , t h e u p p e rm o s t w e ld (SA 1073) i s f u l l y

w i t h i n t h e a c t i v e l e n g t h o f t h e c o r e and t h e lo w e r w e ld (SA 1430) e x te n d s

o n ly a s h o r t d i s t a n c e b ey o n d t h e a c t i v e l e n g t h .

5 .5 R e s u l t s o f A n a lv s i s

5 . 5 .1 T y p es o f A n a ly s e s C o n d u c ted

P r o b a b i l i s t i c f r a c t u r e - m e c h a n i c s c a l c u l a t i o n s w e re p e r fo rm e d t o d e t e r ­

m in e (1 ) t h e c o n d i t i o n a l p r o b a b i l i t y o f v e s s e l f a i l u r e [ P ( f | e ) ] f o r a

num ber o f p o s t u l a t e d O conee-1 t r a n s i e n t s , ( 2 ) t h e s e n s i t i v i t y o f P ( f | e )

t o s m a l l c h a n g e s i n t h e m ean v e d u e s o f c e r t a i n p a r a m e t e r s , (3 ) th e

e f f e c t o f i n c l u d i n g WPS, a n d (4 ) t h e e f f e c t on P (F |e ) o f c e r t a i n p ro ­

p o s e d re m e d ie d m e a s u r e s . The r e s u l t s o f t h e s e e f f o r t s a r e p r e s e n t e d

b e lo w .

5 . 5 . 2 C o n d i t i o n a l P r o b a b i l i t y o f V e s s e l F a i l u r e

The s p e c i f i c t r a n s i e n t s c o n s i d e r e d f o r a d e t a i l e d OCA-P a n a l y s i s a r e

d e s c r i b e d i n C h a p te r 3 , an d t h e o n e s a c t u a l l y c a l c u l a t e d a r e i n d i c a t e d

5.31

i n T a b le 5 . 3 . T h o se t r a n s i e n t s n o t c a l c u l a t e d w e re Ju d g e d t o h a v e

v a l u e s o f P ( f | e ) a t 32 EFPY l e s s t h a n 10’*'^.

F o r t h o s e t r a n s i e n t s c a l c u l a t e d , v a l u e s o f P ( F |e ) w e re d e te r m in e d f o r

s e v e r a l t im e s (EFPY s) i n t h e e x p e c te d l i f e o f t h e v e s s e l . The r e s u l t s

a r e su m m arize d i n T a b le 5 .3 an d a r e p r e s e n t e d g r a p h i c a l l y i n F ig u r e 5 .9

a s P (F |E ) v s EFPY. A lso i n c l u d e d o n t h e a b s c i s s a o f F ig u r e 5 .9 a r e t h e

m ean v a l u e s o f RTNDT an d F a t t h ^ i n n e r s u r f a c e o f t h e v e s s e l f o r w e ld

SA 1430.

A sum m ary o f m ore d e t a i l e d r e s u l t s f o r e a c h t r a n s i e n t c a l c u l a t e d i s

p r e s e n t e d i n d i g i t a l fo rm i n A p p e n d ix E . An ex a m p le i s shown i n T a b le

5 .4 f o r t r a n s i e n t No. 4 4 . The sum m ary s h e e t i n c l u d e s t h e d a t a f o r a

v a r i e t y o f h i s t o g r a m s ; a s e t o f f o u r h i s to g r a m s f o r t r a n s i e n t No. 44 i s

show n i n F ig u r e s 5 .1 0 — 5 . 1 3 .

A p p e n d ix E a l s o i n c l u d e s f o r e a c h t r a n s i e n t c a l c u l a t e d a d e f i n i t i o n o f

t h e t r a n s i e n t i n p u t t o OCA-P (dow ncom er c o o l a n t t e m p e r a tu r e v s t im e ,

p r im a r y - s y s te m p r e s s u r e v s t im e , a n d f l u i d - f i l m h e a t t r a n s f e r c o e f f i ­

c i e n t a t t h e v e s s e l i n n e r s u r f a c e v s t i m e ) , t e m p e r a tu r e d i s t r i b u t i o n s i n

t h e w a l l , an d a s e t o f c r i t i c a l - c r a c k - d e p t h c u r v e s f o r w e ld SA1430 b a s e d

o n m ean v a l u e s o f a l l p a r a m e te r s e x c e p t an d w h ic h a r e - 2 a

v a l u e s . E x am p les o f t h e s e g r a p h i c a l o u t p u t s a r e show n i n F ig u r e s 5 .1 4 —

5 .1 7 f o r t r a n s i e n t No. 4 4 .

5.32

Table 5 . 3 . Summary o f c a l c u la t e d values o f P(F|E) for theOconee-1 p o s tu la ted t r a n s ie n t s

Condi t iona l P r o b a b i l i t y o f F a i l u r e , P(FlE)

EFPY

1.9 6.9 15 .3 23.6 32.0 42.0T ran s i en t* 10^® neutrons/cm’

0 . 164 0.273 0 .,545 0 ,.818 1.,090 1 ,,417

RTNDT** °C

55 65 79 89 97 104

1 2 X 10" ® 3 X 10- ’ 1.7 X 10"®

l A , 5 , 7 1.1 X 10- ® 5.2 X 10" ® 1.6 X 10- ®

4 , 9 1.2 X 10- ® 6.0 X 10- ® 4.0 X 10- “ 1.1 X 10- ® 2.0 X 10- ® 3.4 X 10- ®

6 3 X 10- ’ 1.7 X 10- ® 4.9 X 10- ®

10 3.1 X 10- ® 9.8 X 10- ® 3.1 X 10- ®

14 1.2 X 10- ® 4.8 X 10' ® 2.8 X 10- “ 7.0 X 10" “ 1.3 X 10" ® 2.0 X 10- ®

21 1 X 10- ’ 9 X 10- ’ 5.2 X 10- ®

24 4 X 10- ’ 8.8 X 10- ® 3.8 X 10"® 1.0 X 10- “ 2,2 X 10- “

25 8.4 X 10- ® 7.8 X 10- ® 2.4 X 10” “ 5.2 X 10" “ 9.8 X 10- “

26 , 27 , 32 2.2 X 10- ® 5.0 X 10- ® 2.4 X 10- “ 6.2 X 10- “ 1.3 X 10- ®

28 , 30 2.4 X 10- ® 4.2 X 10" ® 1.6 X 10- “ 4.0 X 10- “ 8.6 X 10- “

29 4.2 X 10- ® 3.8 X 10- ® 4.2 X 10- “ 1.4 X 10" ® 3.0 X 10- ® 5.4 X 10- ®

33 1.2 X 10- ® 1.0 X 10- “ 3.2 X 10- “ 6.5 X 10- “ 1.2 X 10- ®

34 8.3 X 10‘ ® 4.4 X 10- “ 1.1 X 10- ® 1.8 X 10- ® 2.9 X 10- ®

41 7.4 X 10- ® 4.2 X 10- ® 3.2 X 10- “ 9.0 X 10- “ 1.8 X 10- ® 3.0 X 10- ®

44 1.3 X 10- “ 4.0 X 10- “ 1.7 X 10" ® 3.6 X 10- ® 5.4 X 10" ® 8.0 X 10" ®

46 1 X 10- ’ 1.0 X 10- ® 4.4 X 10- ®

57 6.1 X 10- ® 4.5 X 10- ® 1.5 X 10- “ 4.1 X 10- “

♦Refer to Table 6.1 f o r c o r r e l a t i o n of t r a n s i e n t number with d e f i n i t i o n of t r a n s i e n t .

**Mean va lues f o r weld SA1430.

5.33

ORNL-DW G 8 4 -4 4 0 2 ETD

EFPY30 40

1 - 2

4,944

1-3

34

28,301 - 4

UJIL

a.

1-5

1A,5,7 H25

26,27,3246

1 -6

RTNDT (SA 1430) (°F)

180 200 220160

0 0.2 0.4 0.8 1.0 1.40.6 1.2FLUENCE (SA 1430) (10’® neutrons/cm^)

Figure 5.9. P(F 1e ) v s EFPY for Oconee-1 postulated OCAs.

5.34

Table 5 . 4 . Summary s h ee t o f OCA-P output for Oconee-1pos tu la ted t r a n s i e n t No. 44

IPTS OCONEE CLAD 6A 1 0 / 2 0 / 8 3

WELD P ( F / E )-UNADJUSTED--------------------------95%CI SERR P( I NI TI A) N»V

1. FLAWS/M»»3

ADJUSTED-------P ( F / E ) tERR

FO = 1.090D+19

NTRIALS

1 6 . 7 4 D - 0 2 3 . 6 7 D - 0 3 5 . 9 5 6 . 7 5 D - 0 2 0 . 0 9 0 2 . 6 9 D - 0 3 100002 5 . 0 9 D - 0 2 3 . 2 9 D - 0 3 6 . 3 7 5 . 11D-02 0 . 0 9 0 2 . 03D-Q3 100003 7 . 5 6 D - 0 2 3 . 8 6 D - 0 3 5 . 10 7 . 6 1 D - 0 2 0 . 0 1 0 7 . 5 6 D - 0 9 10000

VESSEL 5 . 9 9 D - 0 3 3 . 5 9

DEPTHS FOR INITIAL INITIATION (MM)3. 2 6 . 3 1 2 . 7 1 9 . 0 2 5 . 9 38. 1 5 0 . 8

NUMBER 1033 1619 501 137 26 3 0PERCENT 3 1 . 2 9 8 . 7 15. 1 9. 1 0 . 8 0 . 1 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 10 . 0 2 0 . 0 3 0 . 0 9 0 . 0 5 0 . 0 6 0 . 0 7 0 . 0 8 0 . 0 9 0 . 0 1 0 0 . 0 1 1 0 . 0 1 2 0 . 0

NUMBER 0 0 0 0 2 17 99 1 19 282 535 1006 1296PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 1 0 , 5 1 . 5 3 . 5 8 . 5 1 6 . 2 3 0 , 5 3 9 . 3

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 . 9 2 7 . 8 9 1 . 7 5 5 . 6 6 9 . 9 83. 3 9 7 . 2 11 1.1

NUMBER 79 289 969 1252 699 83 3 0 0 0 0 0PERCENT 2 . 2 8 . 6 2 9 . 2 3 7 . 8 1 9 . 6 2 . 5 0 . 1 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 1 3 . 9 2 7 . 8 91.

NUMBER 0 0 6 7 0PERCENT 0 . 0 0 . 0 9 6 . 2 5 3 . 8 0 . 0

7 5 5 . 6 6 9 . 9 83 . 3 9 7 . 2 1 11. 1 1 2 5 . 0 1 3 8 . 90

0 . 0

0

0 . 0

0

0 . 0

0

0 . 0

0

0 . 0

0

0 . 0

0

0 . 0

5 .35

OCft-P IPTS OCONEE CLflO 6R 10/20/83INITIflTION CRflCK DEPTHS PO- 1.090E19

COS! g .o ■MEh< R-MEh

a. 2 ■

8-<HM 9- 2

3.a C.3 U.7 ia.0 3>.lCfWCK DEPTH, ttl

90.*

Figure 5.10 Histogram of percent initiations vs crack depth for first initiation event (Oconee-1 postulated transient No. 44; at 32 EFPY).

OCn-P IPTS OCONEE CliO 8R 10/20/83TIME OF FfllUJRE FO- 1.090E19

TIME, MIN.

Figure 5 .11. Histogram o f pe rcen t f a i lu r e s vs tim e of f a i lu r e (Oconee-1 p o s tu la te d t r a n s ie n t No. a t 32 EFPY).

5.36

OCn-P IPTS OCONEE CLfO 8fl 10/20/83INITinilON T-RTNDT FO- 1.090E19

o

7 ^ jy V .y ^ ^ 4'r - RTNDT, DEC.C

Figure 5.12 Histogram of percent initiations vs T - RTNDT (weld SA1430) at tip of flaw for all initiation events (Oconee-1 postulated transient No. 44; 32 EFPY).

OCn-P IPTS OCONEE CLflO 6fl 10/^83FO- 1.090E19ARREST T-RTNDT

m

a

7 A* O- ^ 4 -T - RTNDT, DE8.C

Figure 5 .1 3 . Histogram of percen t a r r e s ts vs T - RTNDT (weld SA1430) a t t ip of flaw fo r a l l a r r e s t even ts (Oconee-1 p o stu la ted t r a n s ie n t No. 44; 32 EFPY).

5.37

tD oX R

rrvjr : o

oh-*X ,

IPTS OCONr:^ CLSD 6R 10/20/33

oCD of . ) .

° 8

cna.ECDO)UJ010-

u .EI- o

□ PRISSS. (MPR)o TEMP,(PEG.C.)A HTC( /M?xx2?<K)

0.0 10.0 20.0 30 .0 40.0 50.0 60 .0 80 .0 90 .0 100.0 110.0 120.0

F ig u r e 5 .1 4 . P , T, an d h v s t f o r O oonee-1 p o s t u l a t e d t r a n s i e n t No. 4 4 .

5.38

6£'s

®9tlO0,0 5 ,

Ve S4 *°^?^®Tsue

TIb/j .- ^

^/OZ/Ql“"»a«noSiJI

IPTS OCONEE CLflO 6fl 10/20/83

a/w = 1

a/w = 0 .006

F ig u r e 5 . 1 6 , W a ll t e m p e r a tu r e v s t , a /w f o r O conee-1 p o s t u l a t e d t r a n s i e n t No. 4 4 .

5.40

CRITICflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLRO 6R 1 0 /2 0 /8 3RTNDTO — 6 .7 DE6C ZCU - 0 .2 9 ZNI - 0 .5 5 PO - 1.09E19 L0N8IT

t •

ci -

’‘* * ^ 2 - 0 f l a w * o - » z _ 2_D f l a w

X ♦ O

X

♦

2-m f l a w2-m f l a w<

-WPS

a

o

«

, 2 - m f l a w♦ ♦ V

♦ “ * , ■

..................................... y. • • + ’ * Kt = 220 MPa

X . - < *

• • X *

a «D ♦

2-D f l a w

Xx ^ *>#

Bp

Ba

I ■ ■ I I 1 . . . - . - I . .. . 1 I **^?????y??xxyxx°gg8S g8 iS 88B B B B 8B B H «aiU) 80 ao 70

TIME(MINUTES)too lie K

F ig u r e 5 . 1 7 . C r i t i c a l - c r a c k - d e p t h c u r v e s f o r O conee-1 p o s t u l a t e d t r a n s i e n t No. 4 4 , 32 EFPY, w e ld SA 1430.

5.41

5 . 5 . 3 S e n s i t i v i t y A n a ly s i s

The s e n s i t i v i t y a n a l y s i s w as c o n d u c te d by d e t e r m in in g t h e c h a n g e i n

P (F |E ) c o r r e s p o n d in g t o a ch a n g e i n t h e m ean v a l u e o f e a c h o f s e v e r a l

p a r a m e t e r s . The m ean v a l u e o f o n ly o n e p a r a m e te r w as c h a n g ed a t a t im e

w h i l e a l l o t h e r p a r a m e te r s r e t a i n e d t h e i r o r i g i n a l m ean v a l u e s . The

p a r a m e te r s c h a n g e d w e re RTNDT, Cu, F , f l u i d - f i l m h e a t t r a n s f e r

c o e f f i c i e n t , dow ncom er c o o l a n t t a n p e r a t u r e , p r im a r y - s y s te m p r e s s u r e , an d

f l a w d e n s i t y . The am o u n t o f t h e c h a n g e f o r e a c h p a r a m e te r w as o n e s t a n ­

d a r d d e v i a t i o n , £ind f o r s a n e p a r a m e te r s b o th p l u s a n d m in u s c h a n g e s w e re

m ade b e c a u s e o f a s u s p e c te d s t r o n g n o n l i n e a r i t y .

The v e d u e s o f a u s e d i n t h e s e n s i t i v i t y a n a l y s i s f o r RTNDT,

Cu, and F a r e l i s t e d i n T a b le 5 . 1 , a n d t h e v a l u e s o f t h e f la w d e n s i t y ,

2 -2N, c o r r e s p o n d in g t o t h e a p p l i c a t i o n o f ± 1 a w e re 10 and 10 t im e s t h e

o r i g i n a l m ean v a l u e . The l a ch a n g e i n t h e dow ncom er c o o l a n t t e m p e r a tu r e

c o n s t i t u t e d a l i n e a r c h a n g e i n t e m p e r a tu r e f r a n z e r o a t t im e z e r o t o

28 °C a t a t im e c o r r e s p o n d in g t o t h e minimum p o i n t i n t h e t e m p e r a tu r e v s

t im e c u r v e . From th e n o n , t h e c h a n g e i n t e m p e r a t u r e w as a c o n s t a n t

v a l u e o f 2 8 °C. The l a c h a n g e i n t h e h e a t t r a n s f e r c o e f f i c i e n t , h , w as

0 .2 5 h an d f o r t h e p r e s s u r e , 0 .3 4 MPa.

The r e s u l t s o f t h e s e n s i t i v i t y s tu d y a r e p r e s e n t e d i n T a b le 5 .5 f o r 32

EFPY. T a b le 5 .5 i n c l u d e s t h e v a l u e s o f P ( f | e ) c o r r e s p o n d in g t o t h e o r i ­

g i n a l m ean v a l u e s o f t h e p a r a m e te r s an d t h e c h a n g e s i n P (F |E )

c o r r e s p o n d in g t o e a c h o f t h e l a c h a n g e s .

5.42

I t i s o f i n t e r e s t t o n o t e (b o tto m o f T a b le 5 .5 ) t h a t a s i d e f r o n t h e s e n ­

s i t i v i t y t o N, P (F |E ) i s m o s t s e n s i t i v e by f a r t o t h e r e d u c t i o n i n down­

com er c o o l a n t t a n p e r a t u r e an d i s a b o u t a f a c t o r o f 6 l e s s s e n s i t i v e t o a

r e d u c t i o n i n an d a n i n c r e a s e i n RTNDT. The p r o b a b i l i t y o f f a i l u r e

i s l e a s t s e n s i t i v e t o v a r i a t i o n s i n t h e h e a t t r a n s f e r c o e f f i c i e n t and

t h e p r im a ry s y s te m p r e s s u r e .

5 . 5 .4 E f f e c t o f I n c l u d i n g WPS

D u rin g m any o f t h e p o s t u l a t e d OCAs, t h e s t r e s s i n t e n s i t y f a c t o r , K^, f o r

a l l c r a c k d e p th s f i r s t i n c r e a s e s w i t h t im e , r e a c h e s a meiximum, an d th e n

d e c r e a s e s . F o r t h e s h a l lo w f l a w s t h a t a r e g e n e r a l l y r e s p o n s i b l e f o r t h e

i n i t i a l c r a c k i n i t i a t i o n e v e n t , o n c e b e g in s t o d e c r e a s e i t d o e s so

th r o u g h o u t t h e r e m a in d e r o f t h e t r a n s i e n t . T h is t im e - d e p e n d e n t b e h a v io r

o f K j may p r e v e n t f a i l u r e o f a v e s s e l b e c a u s e a f la w c a n n o t i n i t i a t e

w h i l e K j i s d e c r e a s i n g , e v e n th o u g h 2. 1 . T h is p h e n a n e n o n , w h ic h ,

a s n o te d e a r l i e r , i s r e f e r r e d t o a s w ann p r e s t r e s s i n g (W PS), an d th e

t im e o f i n c i p i e n t WPS i s t h e t im e a t w h ic h becom es e q u a l t o z e r o .

F o r m o s t o f t h e O co n ee-1 p o s t u l a t e d t r a n s i e n t s , WPS c o u ld b e a f a c t o r

b e c a u s e t h e c a l c u l a t i o n s i n d i c a t e t h a t d o e s n o t becom e e q u a l t o

u n t i l a f t e r t h e t im e o f WPS. A t y p i c a l c a s e i s i l l u s t r a t e d i n F ig u r e s

5 .4 and 5 .1 1 . The r e a s o n f o r n o t i n c l u d i n g WPS i n m o s t o f t h e c a l c u l a ­

t i o n s i s t h a t t h e v s t c u r v e s f o r t h e s h a l lo w f l a w s a r e v e r y f l a t ,

m ak in g i t d i f f i c u l t t o d e te r m in e w h e re t h e mciximvun i s . F u r th e r m o r e ,

u n f o r e s e e n p e r t u r b a t i o n s i n p r e s s u r e and c o o l a n t t e m p e r a tu r e m ig h t e x i s t

an d d e f e a t WPS. E ven s o , i t i s o f i n t e r e s t t o s e e w h a t t h e e f f e c t i s

5.43

Table 5 .5 . S en sitiv ity of P(F|E) to 1o ohanges In the mean values of several of the simulated parameters a t 32 EFPY

T ransien tP(FlE)

o r ig in a l mean values

aP(F|E)

Simulated Parameter

RTNOT fo Cu h P

+0 -o +0 +0 -0 +0 ♦o —tJ + 0 —0 +o —0

1 3 % 10-’ *

lA, 5 , 7 5 .2 « 10-‘ *

4 . 9 2.0 X 10-’ -1 .3 X 10-* 3.6 X 10-* -5 .4 X 10-’ 3 .4 X 10- -1 .5 X 10-’ 1.4 X 10-’ 1.0 X 10-’ 1.6 X 10-' 9 .9 X 10"* -1 .9 X 10'* *

6 1.7 X 10 -' *

10 9 .8 X 10 - ' *

14 1.3 X 10-’ -9 .2 X 10-" 3.1 X 10'* -1 .4 X 10-' 2 .2 X 10- -9 .2 X 10 - ' 7.4 X 10-' 9 .7 X 10 -' 5 .4 X 10-' 7 .6 X 10-* -1 .2 X 10’ * -2 X 10-"21 9 X 10-’ *24 1.0 X 10 - ' *25 5.2 X 10 - ' -3 .8 X 10-" 1.4 X 10-* -2 .8 X 10-’ 1.3 X 10- -4 .1 X 10-' 4 .6 X 1 0-' 5 .4 X 10 - ' 2 .8 X 10 - ' 5 .2 X 10‘ * -4 .8 X 10'" *26. 27. 32 6.2 X 10 - ' -4 .1 X 10-" 1.1 X 10-* -2 .2 X 10 - ' 2 .7 X 10- -5 .6 X 10-' 7.0 X 1 0-' 9 .0 X 1 0 - ' -4 .1 X 10-' 9 .0 X 10-' 1.3 X 10‘ * -6 .2 X 10'" -1 .5 X 10-"28. 30 4 .0 X 10 - ' -2 .0 X 10-" 4 .8 X 10-" -7 .0 X 10-’ 1.7 X 10- -3 .5 X 10-' 4 .6 X 10 - ' 5.1 X 10 -' 8 .8 X 10-' 1.0 X 10'* -4 .0 X 10-" -1 .4 X 1Q-"29 3.0 X 10-’ -1 .8 X 10-* 4.1 X 10-* -4 .0 X 10 - ' 7 .0 X 10- -2 .4 X 10-’ 2 .4 X 10-’ 2 .9 X 10-’ 3 .6 X 10 - ' 2 .1 X 10'* -2 .9 X 10'* *

33 6.5 X 10-' -4 .8 X 10-" 1.6 X 10-* -5 .0 X 10 - ' 1.3 X 10- -5 .1 X 10 - ' 5 .5 X 10 -' 6 .5 X 1 0 - ' 2 .0 X 10-' 5.1 X 1Q-* -6 .3 X 10'" *34 1.8 X 10-’ -1 .3 X 10-* 3.8 X 10-* -8 .2 X 1 0-' 2 .7 X 10- -1 .3 X 10-’ 1.1 X 10-’ 1.3 X 10-’ 5 .0 X 10 - ' 9 .9 X 10"* -1 .7 X 10'* *41 1.8 X 10-’ -1 .2 X 10-* 3.2 X 10-* -6 .2 X 1 0 - ' 3 .2 X 10- -1 .3 X 10-’ 1.2 X 10-’ 1.5 X 10-’ -9 .5 X 10-' 1.1 X 10 -' 1.1 X 10'* -1 .7 X 10-* *44 5.4 X 10-’ -3 .4 X 10-* 7.6 X 10-* -2 .0 X 10 - ' 5 .9 X 10- -3 .5 X 10-’ 2.6 X 10-’ 3.1 X 10-’ -2 .2 X 10-’ 3 .6 X 10 -' 1 .8 X 10'* -5 .1 X IQ-* *46 1.0 X 10-' -8 X 10-’57 1.5 X 10-' *

2 « io - ’ 4 X 10-’ 1.0 X 10'* ♦

18 « io - ’

aP (F |E )/P (F |E ) {range fo r a l l tr a n s ie n ts evaluated)

Allevaluated -0 .6 to -0 .7 1 to 3 -0 .01 to -0 .2 1 to 4 -0 .7 to -0 .9 0 .5 to 1.1 0 .5 to 1.5 0.02 to 0 .2 5 to 25 0 .9 to -1 <-0.1 to -0 .8

‘ Decrease in P(F|E) < lOX.

f o r t h e i d e a l i z e d t r a n s i e n t s , an d t h e r e s u l t s o f su o h a s tu d y a r e

p r e s e n t e d i n T a b le 5 . 6 .

T a b le 5 .6 show s t h e t im e o f WPS f o r e a c h o f t h e t r a n s i e n t s c o n s id e r e d

an d t h e c a l c u l a t e d v a l u e s o f P ( F |e ) w i th an d w i t h o u t WPS in c lu d e d i n t h e

a n a l y s i s . I t i s a p p a r e n t t h a t f o r t h e s e i d e a l i z e d t r a n s i e n t s WPS h a s a

v e r y s i g n i f i c a n t e f f e c t .

5 . 5 . 5 E f f e c t o f P ro p o s e d R em e d ia l M e a s u re s on P ( F [ e )

The p ro p o s e d r e m e d ia l m e a s u re s c o n s id e r e d i n t h e f r a c t u r e - m e c h a n ic s s t u ­

d i e s w e re (1 ) r e d u c t i o n i n t h e f l u e n c e r a t e , (2 ) i n - s e r v i c e i n s p e c t i o n

f o r f l a w s i n t h e v e s s e l , ( 3 ) a l i m i t o n r e p r e s s u r i z a t i o n , an d (4 )

a n n e a l i n g o f t h e v e s s e l .

5 . 5 . 5 . 1 R e d u c t io n i n F lu e n c e R a te

The r e d u c t i o n i n f l u e n c e r a t e w as a ssu m ed t o t a k e p l a c e o n J a n u a ry 1 ,

1 9 8 5 , an d i t w as assu m ed t o b e t h e sam e a t a l l c r i t i c a l l o c a t i o n s i n t h e

v e s s e l w a l l . The e f f e c t w as s im p ly t o c h a n g e t h e p r o p o r t i o n a l i t y co n ­

s t a n t b e tw e e n F^ an d EFPY b ey o n d J a n u a r y 1 , 1 9 8 5 . A t t h i s t im e th e

v e s s e l w i l l h a v e b e e n i n s e r v i c e f o r '^7 EFPY, an d t h e f l u e n c e f o r w e ld

SA1430 w i l l be 2 .7 6 x 10^® n e u t r o n s /c m ^ . The i n f o r m a t i o n i n F ig u r e 5 .9

17i s b a s e d o n a f l u e n c e r a t e f o r w e ld SA1430 o f 3 .2 6 x 10

2n e u t r o n s / ( c m *EFPY) f o r t h e p e r io d 5 EFPY t o 32 EFPY. The num ber o f

EFPY c o r r e s p o n d in g t o t h e f l u e n c e i n F ig u r e 5 .9 a f t e r J a n u a r y 1 , 1985 ,

i s

EFPY = 7 + 3 .0 7 xIO "^® f ( F - 2 .7 6 x 10^®) ( 5 .1 9 )o

5.45

T a b le 5 . 6 . E f f e c t o f i n c l u d i n g WPS i n c a l c u l a t i o n o f P ( f 1e ) a t 32 EFPY

T r a n s i e n tP (F lE )

w /oWPS

Tim e o f WPS

(m in )

p ( f ] e )w ithWPS

1 3 X 1 0 "J 27 <10"'^

1A, 5 , 7 5 .2 X 1 0 "° 18

4 , 9 2 .0 X 10"^ 22 <10"^6 1 .7 X 10"^ 28 <10""^10 9 .8 X 10"^ 28 <10"'^14 1 .3 X 10"^ 36 <10"^21 9 X 10""^ 40 <10""^24 1 .0 X 10 18 9 X lO""^25 5 .2 X 10"^ 17 3 X 10"^2 6 , 2 7 , 32 6 .2 X 10"^ 28 3 X 10"^2 8 , 30 4 .0 X 10"^ 18 4 X 10"^

29 3 .0 X 10"^ 20 <2 X 10"®

33 6 .5 X 10"^ 18 3 X 10"®34 1 .8 X 10"^ 18 5 X 10"^41 1 .8 X 10"^ 30 <10"®44 5 .4 X 10"^ 22 <10"®46 1 .0 X 10"^ 20 <10""^

57 1 .5 X 10"^ 20 1 X 10"^

5.46

where

f = f a c to r by which f lu en ce r a t e i s reduced on January 1, 1985

F = in n e r-su rfa c e f lu e n c e fo r weld SA1430 o

For t h i s p a r t ic u la r s tudy , f lu en ce re d u c tio n f a c to rs of 2 , 4 , and 8 were

examined. Using th ese f a c to r s in Eq. 5 .19 r e s u l t s in F^ (32 EFPY) = 6.84 x

I 0 I8 , 4 .80 X 10^®, and 3 .78 x 10 ® neu trons/cm ^, re s p e c tiv e ly , compared to

10.9 X IQI® neutrons/cm 2 fo r f = 1. The corresponding v a lu es o f P(F|E) fo r

the t r a n s ie n t s included in F igu re 5 .9 can be estim ated by e n te r in g these

f lu e n c e s on the a b sc is sa o f F igu re 5 .9 . (The EFPY sc a le i s , o f course ,

in c o r r e c t except fo r f = 1 .) These r e s u l t s a re summarized in Table 5 .7 .

5 .5 .5 .2 In -s e rv ic e In sp e c tio n

In -s e rv ic e in sp e c tio n was assumed to have a c a p a b i l i ty o f f in d in g e i th e r

90? o r 99? o f the su rfa c e flaw s w ith dep ths equal to o r g r e a te r than 6 mm and

none o f the flaw s w ith dep ths l e s s than 6 mm. I t was f u r th e r assumed th a t

a l l flaw s found would be re p a ire d . I f b e fo re th e in -s e rv ic e in sp e c tio n ,

no c a lc u la te d f a i l u r e s were a t t r ib u te d to i n i t i a l flaw s w ith depths l e s s

than 6 mm, then th e 90$ and 99$ in sp e c tio n would reduce P ( f |e ) by fa c ­

to r s o f 0.1 and 0 .0 1 , r e s p e c t iv e ly . However, in most cases th e very

shallow flaw s do r e s u l t in f a i l u r e . The c a lc u la te d e f f e c t of in -s e rv ic e

in sp e c tio n under th ese c o n d itio n s i s in d ic a te d in Table 5 .7 fo r a tim e

in the l i f e o f the v e sse l o f 32 EFPY.

5 .5 .5 .3 L im it on R e p re ssu riz a tio n

The e f f e c t on P (F |e ) o f a l im i t on r e p r e s s u r iz a t io n was in v e s tig a te d by

sp e c ify in g a s in g le l im i t o f 6 .9 MPa. The b e n e f i t o f th i s l im i t i s

5.47

Table 5.7. Benefit of remedial measures,

Transient

Reduction In Fluence In-service Rate on Jan. 1. 1985 Inspection

P(F|e ) InspectionOriginal Rate Reduction Factor Capability**

Mean Values ------------------------------------at 32 EFPT 2 4 8 90J 99>

Limit on Repressurization

P(f 1e ) P„: conditional probability of failure with remedial measure. P(F|e )

Annealing at 9 EFPy

1 3 X 1 0 “ ^ * • 1 • » §

1A , 5 , 7 5 . 2 X 10"® 0 . 0 8 • • • • • • 0 . 1 3 0 . 0 4 0 . 1 9

2 « 1 0 " ^ < • « « « • • • •

4 , 9 2 . 0 X 1 0 "® 0 . 4 0 . 2 0 . 0 3 0 . 2 9 0 . 2 2 0 . 5 0

6 1 . 7 X 10"® • • • 0 . 1 0

1 0 9 . 8 X 10"® 0 . 2 • • • • • • 0 . 0 3 0 . 3 0

14 1 . 3 X 1 0 " ^ 0 . 4 0 . 2 0 . 0 8 0 . 2 8 0 . 2 1 0 . 1 3 0 . 5 4

1 8 « 1 0 " ^ flC*

21 9 X 1 0 " ^ • • •

2 4 1 . 0 X 10"** 0 . 2 0 . 0 5 0 . 0 2 0 . 1 5 0 . 0 6 0 . 3 7

2 5 5 . 2 X 10"^* 0 . 4 0 . 1 0 .06 0 . 2 1 0 . 1 3 0 . 4 2

2 6 , 2 7 , 3 2 6 . 2 X 1 0 " ^ 0 . 2 0 . 0 5 0 . 0 2 0 . 5 5 0 . 5 1 0 . 3 5

2 8 , 30 4 . 0 X lO""* 0 . 2 0 . 0 8 0 . 0 3 0 . 5 0 0 . 4 5 • • • 0 . 3 8

2 9 3 . 0 X 1 0 " ^ 0 . 3 0 . 1 0 . 0 3 0 . 5 6 0 . 5 1 0 . 0 7 0 . 4 3

3 3 6 . 5 X 10"^* 0 . 3 0 . 1 0 . 0 5 0 . 4 6

3 4 1 . 8 X 1 0 " ^ 0 . 4 0 . 2 0 . 1 0 . 6 1

41 1 . 8 X 1 0 " ^ 0 . 3 0 . 1 0 . 0 5 0 . 3 1 0 . 2 4 0 . 5 6

4 4 5 . 4 X 1 0 " ^ 0 . 6 0 . 2 0 . 1 0 . 3 8 0 . 3 1 0 . 0 2 0 . 6 5

4 6 1 . 0 X 1 0 ' ® • • • 0 . 2 8

5 7• l l

1 . 5 X 10 0 . 1 0 . 0 2 • • • 0 . 0 1

•'wRMtlonal proballlty of failure without remedial measure. w/oRM' condl-

**Refer to text for an explanation of Inspection capability and assumption regarding of flaws.

repair

***P(F|E) <10“'.

5.48

p r e s e n t e d i n T a b le 5 .7 f o r 32 EFPY, F o r s e v e r a l o f t h e t r a n s i e n t s t h e

p r e s s u r e d o e s n o t d ro p b e lo w 6 .9 MPa, a n d f o r t h e s e t r a n s i e n t s t h e l i m i t

o n r e p r e s s u r i z a t i o n d o e s n o t a p p l y .

5 . 5 . 5 . 4 A n n e a l in g

A n n e a l in g o f t h e p r e s s u r e v e s s e l w i l l i n c r e a s e t h e f r a c t u r e to u g h n e s s o f

t h e v e s s e l m a t e r i a l , an d t h e am o u n t o f t h e i n c r e a s e w i l l d e p e n d o n th e

a n n e a l i n g t e m p e r a t u r e an d t im e , t h e c h e m is t r y o f t h e m a t e r i a l , an d t h e

num ber o f t im e s t h e v e s s e l i s a n n e a l e d . T e s t r e s u l t s frcmi s m a l l s p e c i ­

m ens i n d i c a t e t h a t e s s e n t i a l l y f u l l r e c o v e r y o f t h e i n i t i a l f r a c t u r e

to u g h n e s s m ig h t b e a c h ie v e d by a n n e a l i n g i n t h e te m p e r a tu r e r a n g e 4 0 0 -

o 14450 C f o r '^200 h . A lth o u g h p r e l i m i n a r y s t u d i e s i n d i c a t e t h a t s u c h a

p r o c e s s w o u ld p r o b a b ly b e f e a s i b l e i n som e PWR p l a n t s , t h e f e a s i b i l i t y

o f a n n e a l i n g t h e O co n ee-1 v e s s e l u n d e r t h e s e c o n d i t i o n s h a s n o t b e e n

e s t a b l i s h e d . N e v e r t h e l e s s , f o r t h e p u rp o s e o f t h i s s t u d y i t w as assu m ed

t h a t th e O c o n e e -1 v e s s e l w o u ld b e a n n e a le d w hen t h e p l a n t a c h ie v e d ' 9

EFPY ( '^ J a n u a ry 1 9 8 7 ) . I n e f f e c t , 9 y r w o u ld b e s u b t r a c t e d frcm i t h e EFPY

s c a l e i n F ig u r e 5 .9 f o r EFPY 2. 9 . The b e n e f i t a t 32 EFPY o f t h i s

assu m ed a n n e a l i n g s i t u a t i o n i s i n d i c a t e d i n T a b le 5 . 7 .

5.49

REFERENCES

1 . F . J . L o s s , R. A. G ra y , J r . , an d J . R. H a w th o rn e , ’’ S i g n i f i c a n c e o f Warm

P r e s t r e s s t o C rac k I n i t i a t i o n D u r in g T h erm al S h o c k ,” R e p o r t NRL/NGREG-8165,

N a v a l R e s e a r c h L a b o r a to r y , N TIS, S e p te m b e r 2 9 , 1 9 7 7 .

2 . R. D. C h e v e r to n an d S . K. I s k a n d e r , ’’ T h e rm a l-S h o c k I n v e s t i g a t i o n s , "

i n " H e a v y -S e c t io n S t e e l T e c h n o lo g y P ro g ram Q u a r t e r l y P r o g r e s s R e p o r t

O c to b e r-D e c e m b e r 1 9 8 0 ," NUREG/CR-1941 (ORNL/NDREG/TM-437), p p . 3 7 -5 4 , U nion

C a rb id e C o r p o r a t io n - N u c le a r D i v i s i o n , Oak R id g e N a t i o n a l L a b o r a to r y .

3 . R. D. C h e v e r to n an d D. G. B a l l , ’’ OCA-P, A P r o b a b i l i s t i c F r a c tu r e - M e c h a n ic s

Code f o r A p p l i c a t i o n t o P r e s s u r e V e s s e l s , " NUREG/CR-3618 (O R N L -5991), U nion

C a rb id e C o r p o r a t io n - N u c le a r D i v i s i o n , Oak R id g e N a t i o n a l L a b o r a to r y ( i n

p r e p a r a t i o n ) .

4 . R. D. C h e v e r to n , D. G. B a l l , an d S . E . B o l t , ’’ T h e rm a l-S h o c k I n v e s t i g a ­

t i o n s , " i n ’’H e a v y -S e c t io n S t e e l T e c h n o lo g y P ro g ram Q u a r t e r l y P r o g r e s s R e p o r t

A p r i l - J u n e 1 9 8 3 ," NUREG/CR-3334, V o l. 2 (0R N L /T M -8787/V 2), p p . 5 7 -7 4 , U nion

C a rb id e C o r p o r a t io n - N u c le a r D i v i s i o n , Oak R id g e N a t i o n a l L a b o r a to r y .

5 . T . U. M a rs to n ( E d . ) , " F la w E v a l u a t i o n P r o c e d u r e s , ASME S e c t i o n X I,

B a ck g ro u n d an d A p p l i c a t i o n o f ASME S e c t i o n X I, A p p e n d ix A, S p e c i a l R e p o r t , "

EPRI N P -719-S R , A m erican S o c i e t y o f M e c h a n ic a l E n g in e e r s , E l e c t r i c Pow er

R e s e a rc h I n s t i t u t e , A u g u st 1 9 7 8 .

6 . L e t t e r fro m F . J . L o ss (NRL) t o R. H. B ry an (ORNL), M arch 3 1 , 1 9 8 1 .

5.50

7 . NRC s t a f f e v a l u a t i o n o f P r e s s u r i z e d T h erm a l S h o ck , S e p t . 1 3 , 1982

d r a f t , a t t a c h m e n t t o t r a n s m i t t a l d o c u m e n t. S ecy 8 2 -4 6 5 , Nov. 2 3 , 1 9 8 2 .

(A v s d .la b le i n NRC p u b l i c d o cu m en t ro o m .)

8 . R. D. C h e v e r to n an d D. G. B a l l , ” T h e rm a l-S h o c k I n v e s t i g a t i o n s , " i n

" H e a v y - S e c t io n S t e e l T e c h n o lo g y P ro g ram Q u a r t e r l y P r o g r e s s R e p o r t

O c to b e r-D e c e m b e r 1 9 8 2 ," NDREG/CR-2751, V o l. 4 (O R N L/TM -8369/V 4), p . 6 8 , O n ion

C a rb id e C o r p o r a t i o n - N u c l e a r D i v i s i o n , Oak R id g e N a t io n a l L a b o r a to r y .

9 . ASME B o i l e r an d P r e s s u r e V e s s e l C ode. S e c t i o n I I I , D i v i s i o n I , Sub­

s e c t i o n NA, A p p en d ix I , A m eric an S o c i e t y o f M e c h a n ic a l E n g in e e r s , New Y o rk ,

1 9 7 4 .

1 0 . R. M. G am ble and J . S t r o s n i d e r , J r . , "A n A ss e s s m e n t o f t h e F a i l u r e R a te

f o r th e B e l t l i n e R e g io n o f PWR P r e s s u r e V e s s e l s D u r in g N orm al O p e r a t io n and

C e r t a i n T r a n s i e n t C o n d i t i o n s , " NDREG-0778, J u n e 1 9 8 1 .

1 1 . W. M a r s h a l l , "A n A s s e s s m e n t o f t h e I n t e g r i t y o f PWR P r e s s u r e V e s s e l s , "

U n i te d K ingdom A to m ic E n e rg y A u t h o r i t y , S eco n d R e p o r t , M arch 1 9 8 2 .

1 2 . R. Y, R u b i n s t e in , " S i m u l a t io n an d t h e M onte C a r lo M e th o d ," I s r a e l

I n s t i t u t e o f T e c h n o lo g y , J o h n W iley & S o n s , New Y o rk , 1 9 8 1 , p p . 1 1 5 -1 1 7 .

1 3 . " R e a c t o r V e s s e l P r e s s u r i z e d T h erm a l S h o ck E v a l u a t i o n , " D PC -R S-1001,

Duke Pow er Company O conee N u c le a r S t a t i o n , J a n u a r y 1 9 8 2 .

1 4 . J . R. H a w th o rn e , N a v a l R e s e a rc h L a b o r a to r y , p e r s o n a l c o m m u n ic a tio n t o

R. D. C h e v e r to n , Oak R id g e N a t io n a l L a b o r a to r y .

5.51

6 .0 PTS INTEGRATED RISK AND POTENTIAL MITIGATION MEASURES

T . J . Burns, Oak Ridge N a t io n a l L a b o ra to ry .

6 .1 I n t r o d u c t io n

The p rec e d in g t h r e e c h a p te r s have o u t l in e d th e p ro ced u res and te ch n iq u es

enployed to e s t im a te th e th r e e fundam ental p a ra m e te rs ( t r a n s i e n t f req u en cy ,

th e rm a l -h y d ra u l ic h i s t o r y , and th e c o n d i t io n a l p r o b a b i l i t y of v e s s e l

f a i l u r e ) r e q u i r e d to q u a n t i f y the r i s k in h e re n t in a PTS t r a n s i e n t .

T h is c h a p te r d i s c u s s e s the means by which th e se th re e in f lu e n c e s a re

i n t e g r a t e d t o y i e l d an e s t im a te d freq u en cy o f v e s s e l f a i l u r e ( th ro u g h -w a l l

c ra c k p e n e t r a t i o n ) , th e r e s u l t s o f t h i s i n t e g r a t i o n p ro c e s s , and, b r i e f l y ,

the impact o f p o t e n t i a l m i t i g a t in g a c t io n s which c o u ld be a p p l ie d to an

Oconee type p l a n t .

6 .2 R isk I n t e g r a t i o n

In o rd e r to q u a n t i f y th e c o n d i t io n a l p r o b a b i l i t y of v e s s e l f a i l u r e fo r

each e n d s ta t e o f the i n i t i a t o r - s p e c i f i c as jrm pto tic even t t r e e s ( i . e . .

Table A.2 ) , two f u r t h e r e s t im a t io n s a re r e q u i r e d . F i r s t , th e in f lu e n c e

o f o p e r a to r a c t io n s in m odify ing the co u rse of a p a r t i c u l a r a sym pto tic

t r a n s i e n t on th e t r a n s i e n t f requency must be q u a n t i t a t i v e l y e s t im a te d , and

second, a th e rm a l - h y d r a u l ic h i s t o r y r e f l e c t i n g the o p e ra to r a c t io n s must

be a s s ig n e d to each o f th e t r a n s i e n t s . The th e rm a l-h y d ra u l ic h i s t o r y

w i l l d i r e c t l y r e l a t e a t r a n s i e n t t o f r a c t u r e m echanics c a l c u l a t i o n s o f the

v e s s e l f a i l u r e p r o b a b i l i t y , g iven th e o ccu rre n c e o f th e t r a n s i e n t .

While t h i s approach i s t h e o r e t i c a l l y a p p e a l in g , th e r e a re s i g n i f i c a n t

o p e r a t io n a l and re s o u rc e problem s a s s o c i a t e d w ith i t . In th e f i r s t p la c e ,

th e th e rm a l -h y d ra u l ic h i s t o r i e s o f a p p ro x im a te ly 6000 t r a n s i e n t s (248

6 . 1

a s y n p to t i c t r a n s i e n t s x ~20 o p e r a to r a c t i o n co m b in a tio n s ) vou ld bave to be

c a l c u l a t e d o r e s t im a te d . M oreover, tb e c o n d i t i o n a l f a i l u r e p r o b a b i l i t y f o r

each t r a n s i e n t mould bave t o be c a l c u l a t e d u s in g tb e f r a c tu re -m e c b a n ic s

t e c h n iq u e s o u t l in e d p r e v io u s l y . Sucb an e f f o r t was c l e a r l y beyond tbe

r e s o u rc e s a v a i l a b l e to t b i s p r o j e c t , and an a l t e r n a t e , a l b e i t l e s s p r e c i s e ,

p ro ced u re was employed.

As n o te d in C hapter 4 . 0 , a l i m i t e d number o f ev e n t sequences mere c a l c u l a t e d

in d e t a i l u s in g tb e TRAC and RELAP codes . These sequences se rved as a b a s i s

f o r tbe e s t im a t io n o f a p p ro x im a te ly 30 a d d i t i o n a l sequences . F r a c tu r e

m echanics c a l c u l a t i o n s ( S e c t io n 5 .0 ) v e re th e n perfo rm ed on a s u b se t of

tb e t o t a l o f a p p ro x im a te ly 60 c a l c u l a t e d and e s t im a te d th e rm a l-h y d ra u l ic

h i s t o r i e s as a f u n c t i o n o f tb e f lu e n c e s u s t a in e d by tb e v e s s e l . Tbe r e s u l t s

o f tb e FM c a l c u l a t i o n s se rv e as tb e b a s i s f o r e s t im a t in g tb e r e q u i re d

P(TWC/E^) f o r tbe t r a n s i e n t s . Table 6 .1 summarizes tb e s e t o f tb e rm a l-

b y d r a u l i c / f r a c t u r e m echanics d a ta a v a i l a b l e f o r use in tb e r i s k i n t e g r a t i o n

p ro c e d u re .

One consequence o f tb e l i m i t e d number o f t r a n s i e n t s t h a t v e re ana ly zed i s a

s e v e re l i m i t a t i o n on tb e number o f o p e r a to r a c t io n s t h a t could be modeled.

I n most c a s e s , tb e o p e r a to r a c t i o n t r e e s d e s c r ib e d in O ia p te r 3 .0 v e re

c o l l a p s e d to accoun t on ly f o r tb e most s i g n i f i c a n t a c t i o n o f th o se p o s s ib le

(b ased on e n g in e e r in g ju d g m en t) . F or most PTS t r a n s i e n t s , t b i s co rre sponds

t o tb e i s o l a t i o n o f a f f e c t e d steam g e n e r a to r . Tbe f a i l u r e b ran ch i s th e n

d e f in e d as tbe la c k o f i s o l a t i o n on tb e p a r t o f tb e o p e r a to r . I n c e r t a i n

c a s e s ( s p e c i f i c a l l y th o se in v o lv in g a l o s s o f a l l f e e d v a t e r ) , tb e p o t e n t i a l

f o r o p e r a to r e r r o r s o f coaunission vas in c o rp o r a te d . An example of t b i s

6 . 2

(fl■u

^

oTJ

(V,

C <

5

CO

s-

cd uCOHCL,

rHI

0)so>4-((1)oc0

) (1)

s ^

oooVO0)

1-HcdH

M-l

CO>

J

Iin

I <r

I I I<i

I H

1

<I 1

Q

I

UJ<tU

2 Z

U »-i n

ar

c

2\-42

Z 2

Z 2

2 2

2 2

2

►-»2

22

2

22

22

22

2

W (-4

2 2

(D>CQ

21Q ^

cn Qc <i <r m

a.tn m

j

J

0) U)2

2

Q.

M

zz

z

z

z10

fiC »>( M »~t

MI-4<l <r

<11- T z z

EEo

cflcu

.-

I

0. CL _i z

111 a u

-0 ffi o N

^ tD

«^10 1il''4I— U)

ttica>o>

>'^''>

''><

r<i .

J_

liEC

C(n

>>

CB

>(

D(

JU

Z

03

(no

Di-<

D(D

i-mi-o

o<

iE

EC

LI-

h-H

I-

J_IO

CI

O >0 N

N

I'l m -0

m N

M m

N

N K

lO

N

N N

N

N N

-O N

N ■4-

^

M

11 •»■ t'l ’4- tv I'l M

M N

I |v

O

O O

O

O •■'• O

O

O O

O O

O

O

O

O O

O O

O

O O

O O

O

O

O

O O

O

'“v o o

oI

-> +

I

I I

I I

I I

I I

I. I

I I

I I

I I

I I

I I

I I

I I

I 1

I I

I I

I I

I I

I ^ quiqiijquiqujuiiijqiijiijiiiuitjuiuiuitijujujiijuiujujqijquitijuiiijuiquj

I ■

o «t

M rf vo '0 -o ^

o -•-* -r4

T-» -.-I *-4 ^0 ri N

fo to <1 't' '0 o (0 n

0^I

ist o

r-i r i n t > -4 to ^

n ro ci n

v\ cj rJ N

ci n r*3 f-i ^ r3 r i ri ( 3

m m

uj u-J aJ ro -3 J r3 r3

I II o I

o

I •

I ^I mIIlUU

COztii 0) D

.

J o

u. ®»

I N

O N

S N

n <t >0 >0 N

h ) in N N

K ro N

N h. s

N N

'O N

«4^ ^

^

to N

«t to

•0

*^

0*

'^

O O

^

'*• O

O

O

r, n>

^ r't

Q> ^

r\ r*t

+

1 I

II

.

ii

T:

Ti

I

iT

iT

iT

iT

i

ii

TT

Ti

Ti

Ti

Ti

Ti

T

UJlU

UJU

UtliJU

lUJU

JUJU

JUJlliL

iJUJL

UU

JLu

UJU

JIlJlxllJiU

JUJU

JUJU

lUlU

IUL

iJUJliiU

tUt

O

O O

O

O

f>l N fv|

O o

o

O O

O 10 O

O O

O O

O ^

O O

O

H f >1 M

O

o O

f I f >1 10 03

O

O

‘d’ M

r "I bT lO

^ t-4 »-l M

T-l M »H M

M «H M

M M

t-4 n|J «Q ^

f^

^ -43

^

O 00 ©

CD hO >0 N >0 ro to >0 GO 03 to «t 00 ro CD 0) CO 00 t^ 00 CO 10 ^

<r ^

10 ^

to CDo

o

o o

o o

o o

o o

o o

o o

o o

o o

o o

o o

o o

o o

c o

o o

o o

o o

o o

-1 I I

I I

1 I

I f

I I

I I

I I

I I

I I

I I

I I

I I

I I

I I

I I

I I

I I

TU

JUIU

JUIU

IUIU

JlilUJtiJlJJtlJlilL

UU

JUJU

JUJU

iuiU

JUJU

JUlU

JUIU

IUIU

lUJU

IUJtJJU

JIlJLlJ

O O

N N

M

fA| M N

M

N N

fv o r . N

N N

N

H N

N ro «t ^

^ -O

«0 O

' -t N

O

10 3 r? -<

M >0 M

to

M 13

to to 13 N

13 tO 10

tO tO

m 13 tO

tO

N f'J f 1

m w

J

N tO

10

O

O O

O O

O O

O

O O

O

O C' o

o o

o o

o o

o o

o o

o o

o o

o o

o o

o o

o+

I I

I I

I i

I I

I I

I I

I I

I I

I I

I I

I I

I I

I f

I I

! I

I I

I I

Iu

JU

JiiJ

uitiJ

tiJiu

uju

ttiiuiiiJ

ijJu

iiiJu

iuJ

iiJiiiu

JU

iiJiiJ

UJ

iiJu

iLiJ

UJ

UiiiiU

JiiitiJ

mu

ibj

o O

' 10 n o

'0 b

i nO b) o

lo

vj \n

bi oi bi

bi in m

b3 ii) to

lo n

co cd o

o

c-i u

f-i to o o

't m

O -O

CD to *t f J

r>l 0) CO CD 0)

00 N 03

05 CO 0) CO

OJ f 3 DO 00 (D

h! 10 b

W

^

0 hi M

rt 03

oo

oo

in

oj

(>

a3

0i

no

3o

oo

in

oo

oo

oo

oo

oN

<i

>o

*c

oi

O'

jo

o'

<j

io

tf

3o

Q^

Mr

-«

00

0 0

'-^

0 0

M-

4M

0'

^-

<M

M^

MQ

Mi

,-

4Q

r^

00

Q0

0'

^0

0 0

’-* t

I I

I I

I I

I <

I I

I 1

I I

I i

I I

I I

I I

I I

I I

I T

I

I I

I I

1 I

UlllliJtiJU

IlilUJL

LlU

iUlU

JliJlitUIU

JliJUJU

JUJljJIiJU

JUJljJIiiliiU

JUlL

illJiUlU

JUlL

iJUJU

J1

.Q

CO 10lO

Q,O

'o

bl•3»

10bl

lO hi

CObl

blbl to

bl10

nbl

tt)>0

^ rj N

VO 'ts

CJ Cl

H10

Nf j to

lo o

blN

lOto

N1

o■»

• •

■•

•t

i■

••

••

4•

••

■ •

■•

••

«•

• •

••

•t

•t

•a

aa

■ a

a J

aa

i■

aa

,1

<5» I

1^N

toto

▼ 4bl

M13

sOto

toto 13

•t13

13to

n to

Mto

to00 N

r Ito

n<r

C'"! M03

'0^

to to ^

toCD

^3t o

sO

niM

ri1-3 •t

m'J3

NCO

O'

o1-4

n 1)

blO

N (D

O'o

iHri

tob

l '0 h-

00Q

^4M

M10 *0 t^ CO cr

oM

C il M

bl'0

N©

#1-4

-4 T-lvt-4

^4 1—4 1-4Cil

Cl

NN

f'lf t C

t MNn

toto

11 Mto

to to to to

to<|-

m<LX

2.1Q 0.

UJ M

Z

UJ DC W <I IL I-

2

u

q: I

COO

Ul tlJ :

3 1

J >

z ri ij. o

O

n

E tn

m >

o

j <i >

-I o

: 3 IX

u X

0) c

cu

ioiL

oo

ai-

O E

a. Ill I- J

E

u z30) E

!CL IX E

I- 3

UJ (L 01

N H N h. 1-1 S O N N tv

0

OO

OO

OO

OO

O1

I 1

I I,

I I

I I

I ui

uiiiiiiiuJiiJUJm

uJuiC

' ^

to M

^4■

■•

••

••

«•

•00

t o U N

03 N 10 f t N

00

N t'3t^N

tOf^'O

Nt'-N

0 O O O O O O O O

1 I

I I

I I

I I

I

IU

I U

JUIU

JUIU

JUJU

JUJU

Jn

00 o

o

o 10 o

o r-i

■4"

4 M b"3

f''! M M

^

t^ «

rC

OQ

3lO

OD

NO

O0

N^ r*.

r> r\T

i

I T

I I

I T

I T

UI

UJllJU

lUIU

JUlU

IUJU

JO'

Ot'-N

Ot^-^N

NO

'-3

O' to to

to

■3 O'

to to M

OO <

^•O

'O'^

OO

'NC

^O

'05

0 O

OO

OO

OO

OO

1 T

I

I I

I I

I I

IU

I U

JU

lUJU

lUiU

IUJ

UJ

Ul

r 3 f t 10 UI t bo

m 10 13

^0 t'*!

CD CD

to

f t CD 03 'O

a iooo«toO

'OoO

'i^t 1-4 T"l

--4 13

C*I

I I

I I

I I

I I

I U

I lilU

lUlU

IUJU

IliJliJUf

N N

0 o

1 I

UI U

I O

’-t

00 O'

/-» r%1

I U

J UI

to b)

O' ooill t!iN

lo

t^ N ^

fv .0 N

to0 •''' •'*'1

I I T

T

T

[UJ

UI U

I UI U

I UI U

IO

O CO M o

oj r-i M

(D rt 00 (1

r 100t' tv r% .-VI

I U

J UJ

M O

tv 0)0 o1

I U

J q(h

IV

N N

tv -0 tv M

* V

n,

i i-k

Q

I I

I I

I T

I

UJ

q U

J UI q

U

I UJo f j in r i o

o >t

-< rt -I rf f J J

in

01 S 111 N |V 00 H

0 o o o o

o1

I I

I I

I I

q UI q q q q qI' um

i> ri IV -o-• tl

I I n T

t n (t

10 10

0- ro -0

oo Jv

O' MO

O

O

<-ii

I I T

I

T

Tq q q

q q

q qIII I I

n

10 O

111 N

'0 ro

01 0 -o -0 to ® -I

0

O' N O' m

o ^n o O O O n O1

I I

I I

I I

q

q q

q q

q

q111

tv 111 iv r I 111 o-0 J l

I I 1 N ^ U to to->f'itotn<ii^a)C

ha)0'111 m

111 Id bi 111 b

i bi 111 b

l O' O

'

<ri

VO

til*-• T'i to ^

bl>0N

© O'

a-4C ii t o ^ blt o ^

bl vft N>

>-• C J t o

10>0 N

> >

f 1 t o bl >0

N ©

O' O—4

N 11

in2

UI 0 ©

© ©

©©

© ©

©©

© ©

© ©

pa

OO

Pu

aft

toto

to to toto

toto to to to

J -J J J JJ

1-41-4 1-4

n2

> > > >

>>

> > >

©to

to to to to u.u. Ll Ll U.Ll Llh*- 1“

HJ

-J t-“ I-*z

t: Z

Z z

22

22 -J

-12

o to ©

(XI ©to

toto to to

>©

© ©

© ©

ccCL

XX

X(jc er

©»4

f'l© ©

© UI ©

© ©<c <t <r <r <t<tct «t<r z

zz z

zz

t-2 H

I- t- 1-1”

1-H t- t-

to1-ft.0_ CL CL CL > O

>O> >

> o

o o

> > o

o©

ft.tsl 0.M

2 2 2

22

2 2 3 3J

J J J JJ

_l JJ

J3

33

J<I_l

■T ri n

( I M "»• b

l -O t- m

O'

-v*

4n

.|ii j

ll

lj

iz

qjjq

jujq

qq

qq

qq

q^

aZ

ZZ

ZZ

ZZ

ZZ

ZZ

ZZ

EO

type of e r r o r i s th e r e s t o r a t i o n o f EFW in an n n c o n t ro l le d manner. I t

must be n o te d , however, t h a t c e r t a i n o p e r a to r a c t io n s , in p a r t i c u l a r the

t r i p / n o t r i p o f th e RCPs on a v a l i d ECCS demand, were n e g le c te d .

By examining th e system s t a t e c a t e g o r i e s f o r each t r a n s i e n t l i s t e d in Table

A.2 to g e th e r w i th the t r a n s i e n t i n i t i a t o r , th e most s i g n i f i c a n t o p e ra to r

a c t i o n ( s ) were d e te rm in e d , and th e p r o b a b i l i t y o f each e n d - s t a t e on the

c o l l a p s e d o p e r a to r a c t io n y i e l d s an e s t im a te o f a t r a n s i e n t frequency

t h a t acc o u n ts f o r o p e r a to r i n t e r v e n t i o n . Then, from the s e t o f a v a i l a b l e

t r a n s i e n t s , th e co r resp o n d in g th e rm a l - h y d r a u l ic h i s t o r y was a s s ig n e d to

each of the t r a n s i e n t s . For th o se t r a n s i e n t s f o r which a d e t a i l e d

even t d e s c r i p t i o n was u n a v a i la b l e ( i . e . , th o se t r a n s i e n t s whose in d iv id u a l

a sy m p to t ic f r e q u e n c ie s were l e s s th a n l .O E -0 6 ) , a d e f a u l t t r a n s i e n t was

a s s ig n e d . T h is d e f a u l t t r a n s i e n t r e p re s e n te d th e h ig h e s t c o n d i t io n a l

p r o b a b i l i t y of f a i l u r e o b ta in e d o f a l l the t r a n s i e n t s c a l c u l a t e d . The

d e f a u l t t r a n s i e n t i s LANLIO in T ab le 6 . 1 , th e LANL c a l c u l a t i o n o f 4

TBVs f a i l e d open a f t e r r e a c t o r t r i p from f u l l power ( see C hap ter 4 . 0 ,

S e c t io n 4 . 3 . 2 . 4 f o r a d e s c r i p t i o n o f t h i s s eq u en ce ) . Table A.3 summarizes

th e r e s u l t s o f th e t r a n s i e n t a ss ignm ent p ro ced u re f o r the 498 t r a n s i e n t s

o b ta in e d by in c o rp o r a t in g o p e r a to r a c t io n s i n t o th e 295 t r a n s i e n t s l i s t e d

in Table A.2 . A lso l i s t e d in Table A.3 a re the c o n d i t io n a l p r o b a b i l i t y

o f f a i l u r e , g iv e n the o ccu rren c e o f th e t r a n s i e n t P(f|E^> ( a t a f lu e n c e

e q u iv a le n t to 32 EFPT), and th e c o n t r i b u t i o n to th e o v e r a l l frequency o f

v e s s e l f a i l u r e jXTWC). By suaiming o v e r a l l t r a n s i e n t s in T ab le A.3 , an

e s t im a te d freq u en cy o f v e s s e l f a i l u r e , f o r the i n i t i a t o r s c o n s id e re d , o f

4 .5 E-06/RY i s o b ta in e d .

6 . 4

In o r d e r to summarize th e r e s u l t s , each t r a n s i e n t l i s t e d in Table A.3

was a l s o c l a s s i f i e d by type o f m a lfu n c t io n in v o lv ed . F or example, a FW

( fe e d w a te r ) t r a n s i e n t in c o rp o r a te s some m a lfu n c t io n o f the feed w a te r system,

an SL (s team l i n e ) t r a n s i e n t in v o lv e s a p r e s s u r e c o n t r o l m a lfu n c t io n , e t c .

A lso , a combined t r a n s i e n t type (SS f o r secondary s id e ) vas used to d e s c r ib e

th o se t r a n s i e n t s t h a t in v o lv e bo th feed w ate r and steam l i n e problem s.

Tab le 6 .2 suaimarizes th e f req u en cy o f v e s s e l f a i l u r e (as a fu n c t io n of

f lu e n c e ) fo r each t r a n s i e n t ty p e . As i n d i c a te d , th e dominant t r a n s i e n t

type i s l a b e le d RES ( i . e . , r e s i d u a l ) and accoun ts f o r those t r a n s i e n t s

whose in d iv id u a l f r e q u e n c ie s were l e s s than l.O E-06 b u t whose cum ulative

f r e q u e n c ie s a r e s i g n i f i c a n t . The t o t a l frequency o f v e s s e l f a i l u r e and the

i n d i v id u a l c o n t r i b u t i o n s o f th e v a r io u s i d e n t i f i e d i n i t i a t o r s as a f u n c t io n

o f EFPT f lu e n c e , and RTNDT a re d e p ic te d g r a p h ic a l l y on F ig u re s 6 .1 a , 6 .1 b ,

and 6 .1 c .

F i n a l l y , i t i s i n s t r u c t i v e to examine those t r a n s i e n t s t h a t dominate the

e s t im a te d f requency o f v e s s e l f a i l u r e . Table 6 .3 l i s t s th o se t r a n s i e n t s

whose c o n t r i b u t i o n t o th e o v e r a l l f requency of v e s s e l f a i l u r e a re >1.0E-08.

These 21 t r a n s i e n t s accoun t f o r ap p ro x im ate ly 95% of the o v e r a l l frequency

and, as can be seen by i n s p e c t i o n , a r e dominated by th e r e s i d u a l components

(59% o f th e t o t a l ) , p a r t i c u l a r l y th o se o r i g i n a t i n g from the r e a c to r t r i p

i n i t i a t o r (21% o f th e t o t a l ) .

6 . 5

Table 6 . 2 . Breakdown o f t(TWC) by tr a n s ie n t type

TYPE TFRE©Fluence for Weld SA1340 (10^® neutrons/cm^)

0.273 0 .595 0 .818 1 .09 1.417

FW 2 .6 -0 1 4 .3 -1 0 4 .1 -0 9 1 .4 -0 8 3 .4 -0 8 6 .7 -0 8

SL 9 .8 -0 1 1 .8 -0 8 1 .8 -0 7 6 .7 -07 1 .6 -0 6 3 .1 -0 6

SS 2 .7 -0 2 2 .9 -0 9 2 .1 -0 8 5 .8 -0 8 1 .1 -07 2 .0 -0 7

LOCA 1 .6 -0 1 6 .1 -1 0 4 .3 -0 9 1 .3 -0 8 3 .0 -0 8 5 .8 -0 8

SGTR 9 .9 -0 3 1 .3 -1 0 8 .1 -1 0 2 .2 -0 9 4 .3 -0 9 7 .3 -0 9

RES 5 .0 -0 4 2 .0 -0 7 8 .5 -0 7 1 .8 -0 6 2 .7 -0 6 4 .0 -0 6

TOTAL 2 .2 -0 7 1 .1 -0 6 2 .6 -0 6 4 .5 -0 6 7 .5 -0 6

6 . 6

> -cc

o

O

ORNL-DWG 84-9482

TOTAL

RESIDUAL “

,-6SL

r 7

SS

FW

LOCA8

SGTR

9

rIO

0 2 5 3520 3 0E F F E C T IV E FULL POWER YEARS (E FPY )

F ig u re 6 .1 a T o ta l and com ponent f r e q u e n c ie s o f v e s s e l th ro u g h w a l l c r a c k as a f u n c t io n o f e f f e c t i v e f u i l power y e a r s .

6.7

ORNL-OWG 84-9481

TOTAL

RESIDUAL SL H

r 6

S3

FWLOCA

>IT

O

I -

O

SGTR

1.750 1.250 . 2 5 0 . 5 0 0 .7 5

FLUENCE FOR WELD SA1430 (lo"'^ NEUTRONS/CM^ )

F ig u re 6 .1 b T o ta l and com ponent f r e q u e n c ie s o f v e s s e l th ro u g h w a l l c ra c k a s a f u n c t io n o f f lu e n c e .

6.8

ORNL-OWG 84-9483

TOTAL

RESIDUAL

SL,-6

SS

>q:

FWLOCACJ

$

O

SGTR

riO

7 0 80 1006 0 9 04 0 5 0

RT^ j3T f o r w e l d SA 1 43 0 ( ° C)

F i g u r e 6 . 1 c T o t a l and c o m p o n en t f r e q u e n c i e s o f v e s s e l th r o u g h w a l l c r a c ka s a f u n c t i o n o f R T „ „ .

NDT

6.9

Table 6.3 Dominant sequences contributing to Oconee-1 PTS risk

REC XIPK DOT SPC FWS ECC rpc EFBBQ XB8NS 3BP TBANS# 1FBBQ P(F/T) P(TWC)

3 FW BT 0 1 0 0 1.6B-01 0VBFO3 9.9B-01 18 1.6B-01 l.O B-07 1.6B -08

24 SL BX 1 0 0 0 6.9BH)1 IBVIEB 9.9B-01 2 6.8B -01 l.O B-07 6.8B-08

53 SL BT 1 1 0 0 2.2B -02 TBVG4 l.O B-02 4 2.2BHM 2.0B-03 4.4B -07

116 SS BT 3 1 0 0 2.4B-03 1BWS9 l.O B-02 9 2.4B-03 2.0B-03 4 .3S -08

147 SL BT 6 0 0 0 5.0BH)4 B S U l 9.9B-01 26 5.0B -04 6.2B-04 3.1E -07

14« SL BT 6 0 0 0 S.OB-04 1BVQ9 l.O B -02 9 5.0B-06 2.0B-03 l.O B -08

151 SL BT 6 0 0 2 3.1B-05 HSLB7 9.9B-01 32 3.1B-0S 6 .28-04 1 .9 B -.815S IBS BT 99 99 99 99 1 . 9 » ^ DBF l.OBHM) 99 1.9B -04 5.4B-03 l.OBHM

208 SS EMFW 3 1 0 0 1 .31-03 1BVS9 l.O B -02 9 1.3B-09 2.0B-03 2.6B -08

228 BBS m m 99 99 99 99 7.2B-05 DBF 1.0E4K)0 99 7.2B-05 5.4B-03 3.9B -07

229 SL LSLB 0 0 0 0 9.6B-04 NSLBl 9.9B-01 26 9.5B -04 6.2B-04 5.9B-07

230 SL LSU 0 0 0 0 9 .6» -04 1BWS9 l.O B -02 9 9.6B -06 2.0B-03 1.9B -08

231 SL TiW P 1 1 0 0 3.0B-09 MSIB3 9 .9 B ^ 1 28 3.0B-OS 4 .0S -04 1.2B -08

233 BBS LSLB 99 99 99 99 5.3H-0< DBF l.OBHM 99 '5.3B-06 5.4B-03 2.9B -08

255 BBS SSU 99 99 99 99 1.4B-05 DBF 1.0B400 99 1.4B-05 5.4B-03 7.6B-08

343 SL LOWW 6 0 0 0 6.1B-0S ta u t 9.9B -01 26 6.0B-05 6.2B-04 3.7B -08

344 SL LOWW 6 0 0 0 6.1B-05 H SU l 9.9B-01 26 6.0B-05 6.2B-04 3.7B -08330 P M LOWW 99 99 99 99 5.9B-0S jta l.OBHM 99 5.9B -05 5.4B-03 3.2BHI7

418 BBS S8U 99 99 99 99 7.8B-03 DBF l.OBHM 99 7.8B-OS 5.4B-03 4.2E-07

442 P M S8L2 99 99 99 99 1.8B-0S DBF l.OBHM 99 1.8B-03 5.4B-03 9.9B-08

467 P M SBIB 99 99 99 99 1.8B-03 DBF l.OBHM 99 1.8B-0S 5.4B-03 9.9B-08

500 BBS SI 99 99 99 99 3.9B-03 DBF l.OBHM 99 3.9B -05 5.4B-03 2 .1» -07

6.10

6.3 P o te n t ia l M it ig a t io n Measures

The e f f e c t s o f p o t e n t i a l m i t i g a t i n g a c t i o n s were examined as a p a r t of t h i s

s tu d y . This s e c t i o n i s n o t in te n d e d as a l i s t o f recommendations b u t i s

p ro v id ed to g iv e in fo rm a t io n on th e r e l a t i v e v a lu e o f a c t io n s which could

be taken p ro v id e d a need to reduce th e i n t e g r a t e d r i s k o f a th ro u g h - th e -

w a ll c ra c k due to PTS i s i d e n t i f i e d . I n a d d i t i o n , i t should be n o ted t h a t

the s a f e ty impact o f m i t i g a t in g a c t i o n s on o th e r types o f ev en ts has no t

been perfo rm ed and th e c o s t b e n e f i t o f th e se a c t io n s has n o t been e v a lu a te d

a t t h i s t im e .

6 .3 .1 L im it P rim ary System R e p r e s s u r i z a t io n

The v e s s e l f a i l u r e p r o b a b i l i t y i s v e ry s e n s i t i v e to p rim ary p r e s s u r e during

th e p o r t i o n o f an o v e rc o o l in g t r a n s i e n t in which th e v e s s e l becomes v u ln e r ­

ab le to b r i t t l e f r a c t u r e . The a c t i o n o f th e h ig h head HPI system i s to

r a p i d l y r e p r e s s u r i z e th e p r im ary system . I f l e f t u n t h r o t t l e d , th e system

may r e p r e s s u r i z e to th e PORV s e t p o in t p r e s s u r e in l e s s th an 20 min.

However, p l a n t p ro c e d u re s c a l l f o r t h r o t t l i n g o f HPI so t h a t the p l a n t P-T

s p e c i f i c a t i o n i s n o t v i o l a t e d .

A p o t e n t i a l m i t i g a t in g measure fo r red u c in g PTS r i s k would be to a s s u re

t h a t the p r im ary r e p r e s s u r i z a t i o n be l i m i t e d to 1000 p s i a . The e f f e c t of

such a l i m i t on r e p r e s s u r i z a t i o n was e v a lu a te d and i t was found t h a t the

f requency of v e s s e l th r o u g h - th e - w a l l c ra c k in g was reduced to 3 .2 x 10“ ^/RY

from the c u r r e n t e s t im a te of 4 .5 x 10 ^/RY f o r 32 EFPY.

6.11

6 .3 .2 E f f e c t o f High SG Level T r ip System

As in d ic a te d in th e system d e s c r i p t i o n , th e SGs a t th e Oconee-1 p l a n t a re

equ ipped w ith in s t r u m e n ta t io n des ig n ed to t r i p th e MFW pumps, shou ld th e SG

l e v e l r e a c h 90%. A lthough th e frequency of v e s s e l f a i l u r e of 4 .5 x 10 ^/RY

in c lu d e s the in f lu e n c e o f t h i s system , i t i s d e s i r a b l e to a s s e s s th e p o ten ­

t i a l m i t i g a t i v e v a lu e o f t h i s system f o r p l a n t s which do n o t in c o rp o ra te a

h ig h SG l e v e l p r o t e c t i o n system .

R a th e r than r e a n a ly z e a l l th e sequences f o r the case o f no-SG p r o t e c t i o n

system , th e e f f e c t of t h i s system was ro u g h ly e s t im a te d . The p r i n c i p a l

e f f e c t of the p ro p e r o p e r a t io n o f the system i s to te rm in a te an MFW

o v e rfe e d t r a n s i e n t . I n th e te rm ino logy of the even t t r e e c h a p te r , t h i s

s w itc h e s a p o t e n t i a l s u s t a in e d MFW ov erfeed t r a n s i e n t (FW c a te g o ry 2) to

an u n s u s ta in e d MFW o v e rfe e d t r a n s i e n t . Thus, one e f f e c t o f the e l im in a t io n

o f the SG p r o t e c t i o n system i s t h a t a l l FW c a te g o ry 1 t r a n s i e n t s become FW

c a te g o ry 2 t r a n s i e n t s . A d d i t i o n a l l y , th e e l im i n a t io n o f th e system reduces

th e f req u en cy o f EFW o v e r fe e d s because the p r i n c i p a l means by which the EFW

system i s i n i t i a t e d ( i . e . , t r i p o f th e MFW pumps) i s no lo n g e r p o s s i b l e .

In e s t i i a a t in g th e v a lu e o f th e SG p r o t e c t i o n system , o n ly the change in

th e f r e q u e n c ie s o f FW c a t e g o r i e s 1 and 2 a re c o n s id e re d . The s l i g h t

o f f s e t t i n g change due to th e r e d u c t io n o f EFW o v e r fe e d s i s n e g le c te d ,

changing a l l p re v io u s FW c a te g o ry 1 t r a n s i e n t s t o FW c a te g o ry 2 t r a n s i e n t s .

T oge ther w ith th e a p p r o p r i a t e , b u t more sev e re t r a n s i e n t d e s c r i p t i o n s ,

t h i s r e s u l t s i n an o v e r a l l f req u en cy o f v e s s e l f a i l u r e o f 6 .1 x 10 ^/RY.

T h is r e p r e s e n t s a 35% in c re a s e in th e o v e r a l l f a i l u r e frequency and i s

i n d i c a t i v e o f th e inq>ortance o f t h i s p a r t i c u l a r sy stem . I t shou ld be n o te d ,

however, t h a t t h i s i s o n ly a rough e s t im a te of th e v a lu e o f th e system .

6.12

A d e t a i l e d r e a n a l y s i s o f th e s e t o f t r a n s i e n t s would be r e q u i re d f o r a

■ore p r e c i s e v a lu e . A d d i t i o n a l l y , i t should be no ted t h a t the p h y s ic a l

l i m i t a t i o n s o f the system v e re e s s e n t i a l l y ignored in a r r i v i n g a t t h i s

e s t i m a t e . I n p a r t i c u l a r , th e p o t e n t i a l fo r s e l f - m i t i g a t i o n of an MFW

o v e rfe e d ( i . e . , th e MFW pump t u r b i n e s t r i p p i n g because o f low steam q u a l i t y

caused by th e o v erfeed ) has been ig n o re d .

6 .3 .3 N eutron F luence Rate R educ tion

The b e n e f i t from red u c in g th e n e u t ro n f lu e n c e r a t e in th e v e s s e l w a l l by

f a c t o r s o f 2 , 4 , and 8 were e v a lu a te d . S ince f lu e n c e w ie ld s a cum ula tive

im pact on v e s s e l RTNDT, th e r e d u c t io n in f lu e n c e r a t e w i l l r e t a r d the

e f f e c t i v e r a t e o f a g in g . F lu e n c e - r a te r e d u c t io n f a c t o r s o f 2 , 4 , and 8

would r e s u l t in PTS r i s k r e d u c t io n s by f a c t o r s o f ap p ro x im ate ly 2 , 6 , and

14 r e s p e c t i v e l y a t 32 EFPY.

6 . 3 .4 E f f e c t o f HPI H ea ting

The h ig h - p r e s s u r e i n j e c t i o n system i s o f concern in PTS e v a lu a t io n because

i t in t ro d u c e s c o ld (50^F) l i q u i d i n t o th e co ld le g s of the RCS prim ary

c lo s e to th e v e s s e l downcomer. V arious lo c a l i z e d phenomena such as plume

fo rm a t io n , m e ta l -w a te r h e a t t r a n s f e r , f l u i d mixing in the co ld l e g , and

f l u i d m ixing in th e downcomer r e g io n w i l l de te rm ine w hether th e v e s s e l w a ll

w i l l be s u b je c te d to te m p e ra tu re s s i g n i f i c a n t l y lower th an th e c o o la n t bu lk

average te m p e ra tu re . As d i s c u s s e d in C hap te r 4 . 0 , S e c t io n 4 . 4 , th e rm a l-

h y d r a u l i c a n a ly se s by Theophanous have de te rm ined t h a t plume fo rm a tio n i s

n o t im p o rtan t f o r th e LANL- and IN E L -ca lcu la ted c a se s where b o th h igh p r i ­

mary p r e s s u re and loop flow s ta g n a t io n o c c u r . T h e re fo re , b u lk mixing may

6 . 13

be r e a s o n a b ly assumed f o r s i t u a t i o n s s i m i l a r to th o se e v a lu a te d by Theo­

phanous .

When in j e c t e d in l a rg e q u a n t i t y , HPI f lo v can cause s i g n i f i c a n t c o o l in g .

Houever, th e concep t of h e a t in g the HPI to 90°F o r 100®F w i l l no t g r e a t l y

in f lu e n c e th e te m p e ra tu re response o f the Oconee-1 p l a n t to o v e rco o l in g

e v e n t s . The amount of system c o o l in g due to HPI i s a s t ro n g f u n c t io n of

system te m p e ra tu re . T h is i s i l l u s t r a t e d by F ig u re 6 . 2 . Simply s t a t e d ,

th e g r e a t e r th e te m p e ra tu re d i f f e r e n c e between th e HPI f l u i d and i t s f i n a l

maximum te m p e ra tu re ( say a t th e co re e x i t ) , th e g r e a t e r the h e a t abso rbed .

As th e maximum system te m p e ra tu re d e c l in e s tow ard th e HPI te m p e ra tu re , the

c o o l in g r a t e w i l l approach z e ro . T h is b e h a v io r i s ex p ressed in F ig u re 6 . 2 .

H eating HPI to 90°F cau ses an o f f s e t of 2 .9 MW ( a t HPI flow co rresp o n d in g

t o o p e ra t io n a t PORV s e t p o in t p r e s s u r e ) . Assuming a b a la n c e between h e a t

in p u t and c o o l in g , a f i n a l te m p era tu re in c re a s e o f c lo se to SO^F cou ld

be r e a l i z e d . I f a n o th e r te m p era tu re -d e p e n d e n t cooldown mechanism, such

as steam g e n e r a to r o v e r fe e d s o r blowdown, i s o c c u r r in g , th e te m p era tu re

b e n e f i t of HPI h e a t in g w i l l be reduced . F or example, a t r a n s i e n t w ith

one TBV s tu c k open w ith f a i l u r e s to i s o l a t e feed w a te r and to t h r o t t l e

HPI w i l l y i e l d l e s s than a lO^F b e n e f i t from r a i s i n g HPI te m p e ra tu re to

90*^F. L a rg e r s e c o n d a ry -s id e cooldown mechanisms would f u r t h e r reduce the

b e n e f i t : i n c r e a s e s in HPI flow r e l a t i v e to th e o th e r cooldown mechanisms

would in c re a s e th e b e n e f i t .

The o th e r a s p e c t of HPI h e a t in g i s the e f f e c t on l o c a l i z e d c o o l in g

phenomena. Loop flow and v e n t v a lv e flow combine w ith HPI flow to y i e l d

a w eigh ted ave rage te m p e ra tu re f o r the m ix tu re . The r e l a t i o n s h i p between

6 . 14

50

HPI a t 50 F

40

HPI a t 90 F30

soc•HrHoouOJ>•H4-1 20u0)

10

600500400300200

System Maximum T e m p e ra tu re ( F)

F ig u re 6 .2 P r im a ry c o o l in g due to HPI flo w a t f u l l r e p r e s s u r i z a t i o n (70 I b / s f lo w , 2450 p s i a ) .

6 . 15

m ix tu re te m p e ra tu re and flow r a t i o o f loop and v e n tv a lv e flow to HPI flow

i s d e p ic te d in F ig u re 6 . 3 . The f i g u r e c o n ta in s s e t s o f c u rv es f o r mixing of

550°F loop flow w ith e i t h e r 50®F o r 90°F HPI and 300®F loop flow w ith 50°F

o r 90°F HPI f low . The loop te m p e ra tu re dom inates th e average te m p era tu re

f o r flow r a t i o s g r e a t e r than 10 ( l o o p ) : l (H PI) . HPI te m p e ra tu re dom inates

f o r r a t i o s l e s s th a n 0 . 1 . At a f low r a t i o o f 1 . 0 , th e b e n e f i t o f HPI

h e a t in g i s o n e - h a l f the HPI te m p e ra tu re d i f f e r e n c e , o r 20^F. The b e n e f i t

d e c re a s e s f o r h ig h e r flow r a t i o s and in c r e a s e s to th e f u l l 40^F v a lu e only

f o r v e ry low flow r a t i o s . A lso in d i c a te d on F ig u re 6 .3 a re th e c a l c u l a t e d

flow r a t i o s f o r s e v e r a l o f the TRAC c a l c u l a t i o n s perform ed by LANL marked

loops A and B r e s p e c t i v e l y . The s o l i d m arkers i n d i c a t e r a t i o s based on

loop flow s a lo n e . The dashed m arkers in c lu d e b o th s ta g n a te d loop and

v e n t v a lv e flow in th e c a l c u l a t i o n s o f flow r a t i o . For some c a se s the

o bserved range i s a l s o n o te d . These cases su g g es t t h a t the flow ing loop

in a t r a n s i e n t w i l l have a f low r a t i o on th e o rd e r o f 10 w h ile a s ta g n a te d

loop w i l l have a r a t i o o f about 1 . 0 . Such c o n d i t io n s m inim ize th e b e n e f i t s

t o be ga ined from h e a t in g th e HPI. Measures to r e s t o r e loop flow would

be o f g r e a t e r b e n e f i t in p r e v e n t in g l o c a l i z e d cooldown s i t u a t i o n s .

O v e r a l l , HPI h e a t in g cou ld p ro v id e s<ne sm all b u t v a r i a b l e b e n e f i t in

te rm s o f downcomer te m p e ra tu re re s p o n s e . The s e n s i t i v i t y o f th e f r a c t u r e

m echanics c a l c u l a t i o n to low downcomer te m p era tu re may t r a n s l a t e th e very

sm a ll te m p e ra tu re b e n e f i t i n t o a m easu rab le r e d u c t io n o f r i s k . However,

o th e r methods w i th g r e a t e r p o t e n t i a l f o r te m p era tu re improvement (such as

loop f low au g m en ta t io n , e t c . ) shou ld be i n v e s t i g a t e d f i r s t .

6 . 16

- LANL 2 " LOCA

B - LANL 6A (4TBV Open)F lo w in g Loop

- LANL 5A (2TBV Open)S ta g n a n t Loop

Loop A, Loop B

O b se rv e d R ange

- LANL PORV LOCA600

— LANL MSLB (B a s e Casc^550.

500 -- SG

3 350--

300—

300 FSG

200 - .

90 Fiiriion_.

so-so FHPI

10(1100 .0 0 1 0 . 0 1

Flow R a t io (in,

Figure 6.3 Downcomer temperature vs loop/HPI flow ratio and comparison with THAC results

6 . 3 .5 I n - S e r v ic e I n s p e c t io n

Improved i n - s e r v i c e in s p e c t io n te c h n iq u e s hav ing th e c a p a b i l i t y of

d e t e c t i n g e i t h e r 90% o r 99% o f th e s u r f a c e f law s w i th d ep th s eq u a l to or

g r e a t e r th a n 6 mm were e v a lu a te d . I t was f u r t h e r assumed t h a t a l l

f la w s found would be r e p a i r e d . I f . b e fo re the i n - s e r v i c e i n s p e c t io n , no

c a l c u l a t e d f a i l u r e s were a t t r i b u t e d t o i n i t i a l f law s w ith d ep ths l e s s than

6 mm. th e n th e 90% and 99% i n s p e c t io n would reduce P(F/E) by f a c t o r s of

0 .1 and 0 .01 r e s p e c t i v e l y . However, in most ca se s th e v e ry sha llow flaw s

w hich would n o t be d e te c te d o r r e p a i r e d make a s i g n i f i c a n t c o n t r i b u t i o n

to f a i l u r e . The c a l c u l a t e d e f f e c t of i n - s e r v i c e i n s p e c t io n under th e se

c o n d i t io n s i s in d i c a te d in Tab le 5 .7 f o r an e f f e c t i v e v e s s e l age of 32

EFPY. For many s ev e re t r a n s i e n t s , th e d e t e c t i o n and r e p a i r o f 90% o r 99%

o f a l l l a rg e f law s would reduce the p r o b a b i l i t y o f v e s s e l f a i l u r e by one-

h a l f . The r e d u c t io n f a c t o r was l i m i t e d by th e f a c t t h a t th e v e ry sha llow

flaw s which would n o t be d e t e c te d o r r e p a i r e d a c t u a l l y make a s i g n i f i c a n t

c o n t r i b u t i o n to th e t o t a l p r o b a b i l i t y o f v e s s e l f a i l u r e .

6 . 3 .6 V esse l A nnealing

A nnealing o f the v e s s e l i s presumed to r e s t o r e th e f r a c t u r e thoughness o f

th e v e s s e l m a te r i a l to i t s p r e - i r r a d i a t e d v a lu e e f f e c t i v e l y c a n c e l l in g th e

e f f e c t s o f n e u t ro n f lu e n c e . The e x t e n t o f reco v e ry w i l l depend on the

c h e m is t ry o f th e v e s s e l m a t e r i a l , th e t im e - te m p e ra tu re c h a r a c t e r i s t i c s o f

th e a n n e a l in g p ro c e d u re , and th e number o f t im es the v e s s e l i s an n ea led .

Assuming f u l l r e c o v e ry , r i s k r e d u c t io n by 1 t o 2 o rd e r s o f magnitude r e l a ­

t i v e to th e r i s k a t 32 EFPY may be a c h ie v e d . However. in some in s ta n c e s

a n n e a l in g may be r e q u i r e d on some p e r io d i c b a s i s i f t h i s measure i s to

6 . 1 8

p re v e n t reg row th of th e r i s k . The f e a s i b i l i t y of in - p la c e v e s s e l an n ea lin g

has n o t been a d d re s s e d in s u f f i c i e n t d e t a i l to a s s u re th e e f f e c t i v e n e s s and

p r a c t i c a l i t y o f t h i s m easu re .

6 .3 .7 O pera to r T ra in in g

O pera to r t r a i n i n g v as n o t a d d re s se d s i> e c i f i c a l ly in t h i s s tn d y . However,

the b e n e f i t s o f v ery e a r l y a c t io n to i s o l a t e a broken steam g e n e ra to r

o r t h r o t t l e HPI to l i m i t r e p r e s s u r i z a t i o n o f the p rim ary were reco g n ized .

W r i t te n p ro ced u re s d i r e c t th e o p e ra to r s to make such b e n e f i c i a l a c t io n

where a p p l ic a b le and c o u ld s i g n i f i c a n t l y m i t ig a te many t r a n s i e n t s . The

time r e q u i r e d f o r the o p e r a to r s to an a ly ze the s i t u a t i o n and app ly the

s p e c i f i e d c o r r e c t i v e a c t io n s w i l l t h e r e f o r e de te rm ine to a g r e a t e x te n t

th e s e v e r i t y o f a t r a n s i e n t .

In th e u n c e r t a i n t y a n a l y s i s (C hap te r 7) , th e s e n s i t i v i t y of the r i s k to

o p e r a to r a c t i o n in th e p e r io d o f 10 to 20 min i n t o a t r a n s i e n t was observed

to be s m a l l . For s e v e re t r a n s i e n t s , a c t i o n s ta k e n in t h i s p e r io d were too

l a t e t o m i t i g a t e the a c c id e n t s . For m ild t r a n s i e n t s , th e o p e ra to r a c t io n s

made l i t t l e d i f f e r e n c e in what were a l r e a d y low PTS r i s k t r a n s i e n t s .

Thus, o p e ra to r t r a i n i n g may be o f s i g n i f i c a n t b e n e f i t i f the response time

to a sev e re o v e rc o o l in g t r a n s i e n t can be reduced to under 10 m in u te s .

O p e ra to r t r a i n i n g may a l s o be b e n e f i c i a l in red u c in g e r r o r r a t e s below

th o se assumed in t h i s a n a l y s i s and th u s r e s u l t i n low er f r e q u e n c ie s f o r

some o f the more s ev e re t r a n s i e n t s .

6.19

7 .0 SENSITIVITY AND UNCERTAINTY ANALYSES

T. J . B u rns« Oak Ridge N a t io n a l L abo ra to ry

7 .1 I n t r o d n c t io n

In a d d i t i o n to tbe e s t im a te o f th e ex pec ted frequency o f v e s s e l f a i l u r e ,

a complementary (and p e rh ap s even more s i g n i f i c a n t ) a n a l y s i s o f the degree

of u n c e r t a i n t y a s s o c i a t e d w ith th e e s t im a te i s r e q u i r e d . In f a c t , g iven some

o f th e p a ra m e te r e s t i m a t io n p ro c e d u re s used in t h i s s tu d y , th e expec ted

f req u en cy o f v e s s e l f a i l u r e d e r iv e d p r e v io u s ly can on ly be reg a rd ed as

a c rude e s t i m a t e . The purpose o f t h i s c h a p te r i s to a s s e s s the degree

o f co n f id e n ce t h a t can be a s s o c ia t e d w ith th e e s t im a te . T h is i s done by

c o n s id e r in g most of th e p a ra m e te rs used in t h i s s tudy as random v a r i a b l e s

and by e s t im a t in g th e in f lu e n c e o f p a ram e te r v a r i a t i o n on th e f i n a l r e s u l t ,

the p r o b a b i l i t y o f a th ro u g h -w a l l v e s s e l f a i l u r e p e r r e a c t o r - y e a r .

7 .2 U n c e r ta in tv A n a lv s is

In o rd e r to a s s e s s the u n c e r t a i n t y in r i s k o f v e s s e l f a i l u r e , the

f requency o f f a i l u r e i s expanded about i t s e s t im a te d v a lue u s ing a T ay lo r

s e r i e s . V esse l f a i l u r e i s a f u n c t i o n o f ev en t f req u en cy , th e rm a l-h y d ra u l ic

c o n d i t io n s , and m e t a l l u r g i c a l s t a t e of th e w a l l . The frequency of f a i l u r e

i s expanded in term s o f i t s independen t v a r i a b l e s as

7.1

8*(TffC) ^ 8<»(TWC)♦ ( n r c ) - ♦(TVC) ----------------- (M-M) + > ------------------- [ T ( E . ) - T ( E . ) ]

8M 7 6T(E.)

+ } 6*(TWC) - (7 .1 )[ ♦ ( E J - ♦ ( E , ) ]

8<>(Ep+ h ig h e r o r d e r term s

where {>(TVC) = f requency o f v e s s e l f a i l u r e ( th ro u g h -w a l l c rac k )

H » m e t a l l u r g i c a l p a ra m e te rs r e p r e s e n t in g the s t a t e of the

p r e s s u r e v e s s e l a t th e time even t E , occu rs

T(E^) » th e rm a l - h y d r a u l ic c o n d i t io n s ( p r e s s u r e , te m p e ra tu re , h e a t

t r a n s f e r c o e f f i c i e n t ) used t o d e s c r ib e ev en t E^

t (E ^ ) = f requency o f o ccu rre n c e of even t E ^

The e x p re s s io n in Eq. 7 .1 i s used i n f in d in g th e v a r ia n c e o f th e e s t im a te dA

f re q u e n c y o f f a i l u r e , o [^(TWC)]. The v a r ia n c e i s th e ex p ec ted v a lu e o f

[♦(TffC) - 4(TWC)] . S quaring th e r ig h t - h a n d s id e of Eq. 7 .1 and expanding ,

<t [*(TVC)] = s V + J J cov[M ,T (E j)] + J V * ( E . ) co v [M ,|) (E p ]i ^ i ^

+ ^ ^m^T(E.) ®®''^tM,T(Ej^) ] + 5 5 ®T(e ) ®T(E.) » T(Ej )1i i j ^ ^

■*■1 I ®T(E.) ®<>(E.) ® ov[T (E j) , ♦< E j) li j ^

'*’ 5 ®m®^(E.) covIM ,I(E j ) ] +5 5 St (E .) ®^(E.) ® °^ tT (E j) , ♦(E^^)]i i j J ‘

H(E. ) i j •*+ h ig h e r o r d e r term s (7 .2 )

7 .2

Where d en o tes the p a r t i a l d e r i v a t i v e w ith r e s p e c t to the v a r i a b l e x,

th e v a r ia n c e s a re d e f in e d by

2 r /Ni (7 .3 )= Ix -x l p (x )d x

and the c o v a r ia n c e s by

c o v [x ,y l = [ y - ^ Ix- 'x1p(x ,y)dxdy (7 .4 )

I f i t i s assumed t h a t

(1) N and T(E^) a re independen t v a r i a b l e s ,

(2) M and 4>(Ej,) a r e independen t v a r i a b l e s ,

(3) T(E^) and independen t f o r i j ,

(4) T(E^) and independen t v a r i a b l e s ,

(5) {>(E^) and independen t f o r i ^ j ,

and i t i s f u r t h e r assumed t h a t h ig h e r o rd e r term s can be ig n o red , th e

v a r ia n c e o f the r e s u l t i s g iv e n by

."(Kno) - sV ♦ } . } s% „ 5 ,

1 1 , 1 1 1 i

Each o f the components M, T (E ^ ) , and 4>(E^) o f Eq. 7 .5 a c t u a l l y r e p r e s e n t

a s e t of p a ra m e te rs , and each i s c o n s id e re d s e p a r a t e ly when perfo rm ing the

c a l c u l a t i o n s . F i r s t , a d i s c u s s i o n of the assum ptions n e c e s s a ry to g e t to

th e form o f Eq. 7 .5 i s r e q u i r e d .

7 .3 D is c u s s ion o f AssumBt i q a s

Most of the assum ptions r e q u i r e d to g e t to the form o f Eq. 7 .5 a re

re a so n a b ly a c c u r a te . For i n s t a n c e , i t i s l i k e l y t h a t the m e ta l l u r g i c a l

c o n d i t io n o f the v e s s e l w a l l a t the b e g in n in g of a t r a n s i e n t w i l l be

7.3

independen t o f th e t r a n s i e n t . O ther assnm ptions a re n o t as a c c n ra te«

however. F o r i n s t a n c e , an im p lied assnm ption in th e development has been

t h a t the e r r o r s a s s o c i a t e d w i th each v a r i a b l e a re u n b ia se d . T h is i s

o b v io n s l j n o t th e c a s e .

One source of b i a s i s the e r r o r a s s o c i a t e d w i th th e rm a l -h y d ra u l ic m ode ling .

When u n c e r t a i n t i e s a re p r e s e n t , the tendency i s t o e r r on th e s id e of

c o n s e rv a t is m . Hie many c o n s e rv a t iv e a ssu m p tio n s p r e s e n t in th e computer

models tend to b i a s th e p r e s s u r e s , t e m p e ra tu re s , and h e a t t r a n s f e r

c o e f f i c i e n t s r e s u l t i n g from t r a n s i e n t c a l c u l a t i o n s .

The same type o f b i a s i s p r e s e n t in th e m e t a l l u r g i c a l c a l c u l a t i o n s . Where

r e a l i s t i c numbers can n o t be p r e c i s e l y o b ta in e d , c o n s e rv a t iv e assum ptions

a r e made.

A t h i r d , and p o s s i b ly th e most s i g n i f i c a n t , sou rce o f b i a s in th e e r r o r s

comes from th e lumping o f a l a rg e c l a s s o f t r a n s i e n t s . F or a g iven

i n i t i a t o r , many d i f f e r e n t e v e n ts a re p o s s i b l e , depending on th e o p e r a to r

a c t i o n . Of th e s e many e v e n t s , o n ly two ( o r sometimes th r e e ) a re a n a ly z e d ,

and th e p r o b a b i l i t y a s s o c i a t e d w ith a l l the e v e n ts i s d i s t r i b u t e d to th o s e .

The e v e n ts examined a r e the most " s i g n i f i c a n t " in term s o f p r e s s u r i z e d

the rm al shock. This te n d s t o b i a s th e r e s u l t s toward th e se s i g n i f i c a n t

e v e n t s .

A nother r e q u i r e d assum ption i s t h a t the c o v a r ia n c e between a l l v a r i ­

a b le s ( th e r m a l - h y d r a u l i c c o n d i t i o n s , m e t a l l u r g i c a l p a ra m e te r s , and even t

f r e q u e n c ie s ) be z e r o . As m en tioned , t h i s i s p ro b a b ly a c c u r a te f o r most

v a r i a b l e s . F o r some, however, th e c o v a r ia n c e may be s i g n i f i c a n t .

7 .4

Tliis s i g n i f i c a n t c o v a r i a n c e , to g e th e r w ith the b ia s d is c u s s e d above, i s

enough to make the r e s u l t s o f c a l c u l a t i o n s us ing Eq. 7 .5 l i t t l e b e t t e r

th a n o rd e r^ o f-m ag n itu d e d e t e r m in a t io n . Once t h i s hand icap i s r e a l i z e d , the

c a l c u l a t i o n s may p roceed as d e s c r ib e d in the fo llo w in g s e c t i o n s .

7 .4 T r a n s ie n t Freouencv U n c e r t a i n t i e s

The f req u en cy o f a p a r t i c u l a r t r a n s i e n t , depends on the i n i t i a t o r

f r e q u e n c i e s , the b ra n c h p o in t p r o b a b i l i t i e s , and the human e r r o r

p r o b a b i l i t i e s used in th e o p e r a t o r a c t i o n t r e e s . These com prise the

independen t v a r i a b l e s deno ted by . The c o n d i t io n a l frequency of a

p a r t i c u l a r t r a n s i e n t r e s u l t i n g from a s p e c i f i c i n i t i a t o r , , can be

e x p re s se d as

♦ ( E . / I . ) = ♦ ( ! . ) I I P (BPp ) H P ( H P . ) (7 .6 )" J J ksE . ® keE. ^

The r e q u i r e d p a r t i a l d e r i v a t i v e s a r e th en g iv e n by

6*(TffC) P(F/M,T(E^> nP (B P ^) I lP (H F j ,)keEj kaEj

= P ( F / I ) (7 .7 )

8*(TffC) 5 5 P(F/M, T (E .) r iP (B P-) riP(HF. = , , ksE. ksE.8*P(PBj) J ^

)

= P (F /B P j) , and (7 .8 )

8*(TffC) 5 ♦ d j ) 5 P(F/M. T (E .) r iP (B P .) riP(HF,-------------------- 38*P(HFj) kjtl

)

= P(F/HFj) (7 .9 )

As n o ted in Eq. 7 .7 th ro u g h 7 . 9 , th e p a r t i a l d e r i v a t i v e s r e q u i r e d in the

u n c e r t a i n t y a n a l y s i s co rresp o n d to s p e c i f i c c o n d i t io n a l p r o b a b i l i t i e s , a

7 .5

f a c t t h a t f a c i l i t a t e s b o th t h e i r c a l c u l a t i o n and t h e i r i n t e r p r e t a t i o n . For

exam ple, Eq. 7 .7 i n d i c a t e s t h a t th e r e q u i r e d c o n s ta n t f o r each i n i t i a t o r

examined i s j u s t the c o n d i t io n a l p r o b a b i l i t y o f v e s s e l f a i l u r e , g iv e n the

o ccu r re n c e o f th e i n i t i a t o r . S i m i l a r l y , the p a r t i a l d e r i v a t i v e r e q u i r e d

f o r the b ra n c h p o in t c o n t r i b u t i o n to the v a r ia n c e i s j u s t th e c o n d i t io n a l

p r o b a b i l i t y of f a i l u r e g iv e n t h a t b ran ch p o in t BP^ i s p r e s e n t in the

d e s c r i p t i o n of the t r a n s i e n t f o r each i n i t i a t o r summed over a l l

i n i t i a t o r s and E . .1

Table 7 .1 c o n ta in s the i n i t i a t o r f r e q u e n c ie s and m u l t i p l i c a t i v e u n c e r t a i n t y

f a c t o r s used in t h i s s tu d y . These in c lu d e the v a r ia n c e in th e e s t im a te

o f each i n i t i a t o r f requency and a p a r t i a l d e r i v a t i v e r e l a t i n g t h i s v a r ia n c e

to the v a r i a n c e in ^(TWC).

7 .5 Branch P o in t U n c e r t a in t i e s

Due to th e t r a n s i e n t c a t e g o r i z a t i o n p ro c e s s employed in e s t im a t in g the

th e rm a l - h y d r a u l ic and f r a c t u r e mechanic p a ra m e te r s , the a n a l y s i s o f the

e f f e c t o f b ra n c h p o in t p r o b a b i l i t y u n c e r t a i n t i e s on the f req u en cy o f v e s s e l

f a i l u r e r e q u i r e s a ts ro -s tep p ro c e d u re . The b ra n c h p o in t c o e f f i c i e n t s

a r e e s t im a te d by f i r s t d e te rm in in g the c o n d i t io n a l p r o b a b i l i t y of v e s s e l

f a i l u r e g iv e n o c c u rre n c e o f a c e r t a i n c a te g o ry t r a n s i e n t . Then the

c o n d i t i o n a l p r o b a b i l i t y o f t h a t c a te g o ry t r a n s i e n t g iven a s p e c i f i c b ran ch

p r o b a b i l i t y i s c a l c u l a t e d , i . e . ,

P[*(E^) BPj] = J p [* (E ^ ) /C a t^ ]P [C a t^ /B P j] (7 .10 )h

A su pp lem en ta l b e n e f i t o f t h i s tw o -s ta g e p ro c e s s i s t h a t th e c o n d i t io n a l

p r o b a b i l i t i e s o f v e s s e l f a i l u r e , g iv e n s p e c i f i c t r a n s i e n t c a t e g o r i e s , a re

7 .6

Table 7 .1 I n i t i a t o r frequency a n a ly s i s

P aram ter Frequency P a r i t a l Hu V ariance C o n tr ib u t io n

RT 6.0E+00 3.4E-07 6.2E+00 2.1E+00 2.4E-13

EMFW l.O E-01 4 .4E-06 1.3E-01 1.4E-02 2.3E-13

LSLB l.O E-03 6.6E-04 1.2E-03 4.4E-07 1.9E-13

SSLB l.O E-02 7.8E-06 1 .3E-02 1.4E-04 8.7E-15

LOMFW 5.0E-01 8.5E-07 6.7E-01 3.6E-01 2.6E-13

SBLl l.O E-01 8.4E-06 1.3E-01 1.4E-02 l.O E-12

SBL2 l.O E-02 l . l E - 0 5 1 .3E-02 1.4E-04 1.7E-14

SGTR l.O E -02 l.O E-05 1.3E-02 1.4E-04 1.6E-14

SI l.O E -02 2.1E-05 1 .3E-02 1.4E-04 6.5E-14

7.7

o b ta in e d and can be used to e s t im a te the PTS c h a l le n g e on a system -

f u n c t i o n a l b a s i s .

Once the c o n d i t i o n a l p r o b a b i l i t i e s of v e s s e l f a i l u r e f o r s p e c i f i c c a t e g o r i e s

have been o b ta in e d , i t i s r e l a t i v e l y s t r a i g h t f o n r a r d to sum those end-

s t a t e s (Ej^) t h a t a r e c l a s s i f i e d as be ing in a s p e c i f i c c a te g o ry and t h a t

in v o lv e th e b ran ch p o in t in q u e s t io n . The c o n d i t i o n a l p r o b a b i l i t i e s o f

a s p e c i f i c c a te g o ry b e in g s e l e c t e d can th e n be d e te rm in e d . I n c o rp o ra t in g

th e se v a lu e s i n t o Eq. 7 .1 0 and u s in g Eq. 7 .7 and 7 .9 p e rm i ts the r e q u i r e d

p a r t i a l d e r i v a t i v e s to be d e te rm in e d .

T able 7 .2 summarizes the r e s u l t s o f the b ran ch p o i n t s e n s i t i v i t y / u n c e r t a i n t y

a n a l y s i s f o r those e n d - s t a t e s t h a t meet th e i n i t i a l c r i t e r i o n of t (E ^ ) >

l .O E -0 6 . The a n a l y s i s f o r the u n c e r t a i n t y a t t r i b u t a b l e to th o se e n d - s t a t e s

n o t s p e c i f i c a l l y i d e n t i f i e d ( i . e . , the r e s i d u a l u n c e r t a in t y ) i s d e s c r ib e d

b e lo v .

7 .6 R es id u a l Branch P o in t A n a lv s is

Since th e t r a n s i e n t s w i th e s t im a te d f r e q u e n c ie s below l.O E -6 were n o t

examined, i d e n t i f i c a t i o n o f a s p e c i f i c s e t o f b ra n c h p o i n t s com pris ing each

t r a n s i e n t i s n o t p o s s i b l e . However, i t i s known t h a t a l l th e r e s i d u a l

t r a n s i e n t s in v o lv e one b ran ch p o in t f o r each systma s t a t e e v e n t . Thus,

as an upper bound on u n c e r t a i n t y f o r th e r e s i d u a l t r a n s i e n t s , i t i s assumed

t h a t the b ran ch p o in t having th e l a r g e s t u n c e r t a i n t y f o r a g iven system

s t a t e even t was s e l e c t e d . T r a n s ie n ts d e f in e d by t h i s s e l e c t i o n of b ran ch

p o i n t s do n o t n e c e s s a r i l y co rrespond to e i t h e r the s p e c i f i c t r a n s i e n t s

o b ta in a b le u s in g th e system s t a t e t r e e s o r even p h y s i c a l l y p o s s i b le

7 .8

Table 7 . 2 Branch po in t a n a ly s i s snamary

Type Mu V ariance P a r t i a l C o n t r ib u t io n Branch: #

SPC 9.5E-04 7.2E-07 3.5E-07 8.8E-20 TSV5-1 1

SPC l.O E-03 8.0E-07 5.3E-06 2.3E-17 TBV5-01 1

SPC l.O E-04 8 .0E-09 1.2E-06 l . l E - 2 0 TBV5-01 2

SPC 8.0E-02 5.1E-03 3.8E-06 7.3E-14 SSRV-01 1

SPC l.O E-01 6 .0E-03 2.2E-06 3.9E-14 TSVS-2 1

SPC l.O E-01 8.0E-03 2.5E-09 5.0E-20 TBV8-02 1

SPC l.O E-01 8.0E-03 4.6E-11 1.7E-23 TBV6-02 1

SPC l.O E-01 8.0E-03 4.8E-07 1.8E-15 SERV-02 1

FWS 9.4E-01 7 .2E-01 4.3E-09 1.3E-17 MFWRB 0

FWS 2.8E-02 6 .3E-01 1.5E-05 1.4E-13 MFWRB 1

FWS l.O E-01 8.0E-03 4.1E-07 1.4E-15 MFWRB 2

FWS 2.8E-02 6 .3E -04 5.2E-08 1.7E-18 MFWRB 3

FWS 4.4E-03 1.6E -05 9.6E-07 1.4E-17 HLTRIP 1

FWS 5.6E-03 2 .5E -05 1.2E-06 3.4E-17 EFW IN 1

FWS 1.4E-03 1.6E -06 1.2E-06 2.2E-18 EFW IN 2

FWS 3.4E-03 9.3E -06 3.6E-06 1.2E-16 EFW CONTL 1

FWS l.O E-01 8.0E-03 9.4E-09 7.0E-19 EFW CONTL 2

ECC 1.3E-03 1.4E -06 2.9E-07 l . l E - 1 9 HPI FAIL 1

ECC 4.0E-05 1 .3E-09 O.OE+00 O.OE+00 HPI FAIL 1

PPC l.O E-05 8 .0E-11 5.7E-07 2.6E-23 PORV CLSD 1

PPC 5.0E-01 2 .0E-01 4.2E-09 3.5E-18 BLCK VLVE 1

PPC 2.0E-02 3.2E -04 l . l E - 0 6 3.5E-16 SRV RE 1

PPC 2.7E-02 5 .8 3 -0 4 4.6E-07 1.2E-16 PORV RE 1

7 .9

t r a n s i e n t s . R a th e r t h i s p ro ced u re s e rv e s as a means o f e s t im a t in g an upper

bound on the u n c e r t a i n t y a t t r i b u t a b l e to b ran ch p o i n t s of sm all p r o b a b i l i t y

t r a n s i e n t s . The e f f e c t o f i n i t i a t o r f req u en cy u n c e r t a i n t y r e l a t i v e to

th e se same t r a n s i e n t s has a l r e a d y been accoun ted f o r in th e v a lu e s f o r

th e i n i t i a t o r f req u en cy c o n t r i b u t i o n . S ince no o p e r a t o r i n t e r v e n t i o n vas

assumed f o r the r e s i d u a l t r a n s i e n t s , no u n c e r t a i n t y because of th e human

f a c t o r component i s a p p r o p r i a t e .

7 .7 Human F a c to r A n a lv s is

Because of th e t r a n s i e n t assigxunent p ro ced u re u sed , i t v as n e c e s s a ry

to reduce th e o p e r a to r a c t io n t r e e s down to the s in g le o p e r a to r a c t io n

most s i g n i f i c a n t to the t r a n s i e n t . T h is r e d u c t io n p r e v e n ts a d e t a i l e d

e s t i m a t io n of th e in d iv id u a l o p e r a to r a c t i o n com pris ing th e v a r io u s a c t io n

t r e e s . However, i t i s p o s s ib le to o b ta in an e s t im a te o f th e u n c e r t a i n t y in

exp ec ted o p e r a to r a c t i o n . The human f a c t o r p r o b a b i l i t i e s f o r th e se a c t io n s

a r e 1 .2 E -2 . Using t h i s as a mean, and an u n c e r t a i n t y f a c t o r of 30,

produced a c o n t r i b u t i o n to the v a r ia n c e in ^(XVC) o f 5.2E-13/RY^.

7 .8 F r a c tu r e M echanics A n a lv s is

The s e n s i t i v i t y c o e f f i c i e n t s and p a r t i a l d e r i v a t i v e s f o r the v a r io u s

f r a c t u r e m echanics p a ram e te rs were o b ta in e d by re ru n n in g th e f r a c t u r e

m echanics c a l c u l a t i o n w i th on ly a s in g le p a ra m e te r change. A l l p a ra m e te rs

a n a ly z e d , w ith th e e x c e p t io n o f the f law d e n s i t y , were assumed to be

r e p r e s e n t a b l e by normal d i s t r i b u t i o n s . The f law d e n s i t y was assumed to be

log-norm al w ith a mean o f 1 .0 and a m u l t i p l i c a t i v e f a c t o r o f 300.

7 .1 0

7.9 Therm al- H y d ra u l ic s A n a lv s is

The p a r t i a l d e r i v a t i v e r e q u i r e d by the u n c e r t a i n t y a n a ly s i s f o r the th r e e

p r i n c i p a l th e rm a l—h y d r a u l i c v a r i a b l e s (p» T, and h) was o b ta in e d i n an

analogous manner to t h a t u sed f o r th e f r a c t u r e mechanics v a r i a b l e s . Even

though i t ap p ea rs t h a t c o n se rv a t is m s were in c lu d e d i n th e th e rm a l-h y d ra u l ic

a n a ly s e s , i t was n e c e s s a r y to assume a normal d i s t r i b u t i o n f o r a l l th r e e

th e rm a l—h y d r a u l i c v a r i a b l e s , s in c e on ly l i m i t e d in fo rm a t io n was a v a i l a b l e .

7.10 Snmmarv and D is c u s s io n

T able 7 .3 summarizes the r e s u l t s f o r a l l p a ram e te rs examined as p a r t of

the u n c e r t a in t y a n a l y s i s . The e s t im a te d s ta n d a rd d e v ia t io n in th e f r e ­

quency o f v e s s e l f a i l u r e . er[d (TWC)] i s 5E-5/RT. The expec ted v a lu e of

i (TWC) o b ta in e d i n t h i s s tu d y was 4 .5E-6/R T, and to g e th e r th e se two

p a ra m e te rs c h a r a c t e r i z e th e d i s p e r s io n and c e n t r a l tendency o f the f i n a l

d i s t r i b u t i o n . They do n o t , however, i d e n t i f y th e type o f d i s t r i b u t i o n . I t

i s e v id e n t t h a t th e f req u en cy o f f a i l u r e w i l l be n o n n e g a t iv e . The s ta n d a rd

d e v i a t i o n , however, i s 10 tim es th e e s t im a te d v a lu e . T h is would su g g es t a

lo g —normal d i s t r i b u t i o n , r e s u l t i n g i n th e co n f id en ce i n t e r v a l s l i s t e d in

Tab le 7 .4 .

The amount o f d i s p e r s i o n in th e r e s u l t a t t r i b u t a b l e to the v a r ia n c e o f each

p a ra m e te r has been c a l c u l a t e d and i s t a b u l a t e d in Table 7 . 3 . As in d i c a te d ,

th e m a jo r i t y of u n c e r t a i n t i e s (60%) can be a t t r i b u t e d to the u n c e r t a in t y

in h e re n t in th e te m p e ra tu re h i s t o r i e s used to c h a r a c t e r i z e the t r a n s i e n t s .

T h is i s due to th e l a rg e p a r t i a l d e r i v a t i v e d e r iv e d f o r t h i s pa ram ete r

(1 .4E —6/RY p e r C ) . coup led w ith the la rg e assumed p a ram ete r u n c e r t a in t y

(<y = 2 8 °C ) .

7.11

Table 7 .3 S e n s i t i v i t y / u n c e r t a i n t y r e s u l t s suausary

C la ss P a r a a e t e r Type Mn V ariance P a r t i a l C o n t r ib u t io n Branch: #

FREQ RT INIT 6.0E+00 2.0E+00 3 .43 -07 2.3E-13 TSVS 1

FREQ EMFW INIT l.O E -01 8.0E-03 4.4E -06 1.5E-13 TBVS-01 1

FREQ LSLB INIT l.O E -03 3.3E-07 6 .6E-04 1.4E-13 TBVS-Cl 2

FREQ SSLB INIT l.O E -02 8.0E-05 7 .8E-06 4.8E-15 SSRV-01 1

FREQ LOMFW INIT 5.0E-01 2.0E-01 8.5E-07 1.5E-13 TSVS-2 1

FREQ SBLl INIT l.O E -01 8.0E-03 8.4E-06 5.7E-13 TBVS-02 1

FREQ SBL2 INIT l.O E -02 8.0E-05 l . l E - 0 5 9.7E-15 TBVS-C2 1

FREQ SGTR INIT l.O E -02 8.0E-05 l.O E-05 8.7E-15 SSRV-02 1

FREQ SI INIT l.O E -02 8.0E-05 2.1E-05 3.6E-14 MFWRB 0

FREQ BP SPC 9.5E -04 2.4E-06 3.5E-07 2.9E-19 MFWRB 1

FREQ BP SPC l.O E-03 2.6E-06 5.3E-06 7.4E-17 MFWRB 2

FREQ BP SPC l.O E-04 2.6E-08 1 .2E-06 3.6E-20 MFWRB 3

FREQ BP SPC 8.0E -02 1 .7E-02 3.8E-06 2.4E-13 HLTRIP 1

FREQ BP SPC l.O E-01 2 .6E-02 2.2E -06 1.3E-13 EFW IN 1

FREQ BP SPC l.O E-01 2.6E-02 2.5E-09 1.6E-19 EFW IN 2

FREQ BP SPC l.O E-01 2.6E-02 4.6E-11 5.5E-23 EFW CONTL 1

FREQ BP SPC l.O E-01 2.6E-02 4.8E-07 6.0E-15 EFW CONTL 2

FREQ BP FWS 9.4E-01 2.3E+00 4.3E-09 4.2E-17 HPI FAIL 1

FREQ BP FWS 2.8E -02 2.1E-03 1.5E-05 4.6E-13 CFT FAIL 1

FREQ BP FWS l.O E-01 2.6E-02 4.1E-07 4 .5E-15 PORV CLSD 1

FREQ BP FWS 2.8E -02 2.1E-03 S.2E-08 5.6E-18 BLCK VLVE 1

FREQ BP FWS 4.4E-03 5.1E-05 9.6E-07 4.6E-17 SRV RE 1

FREQ BP FWS 5.6E-03 8.2E-05 1.2E-06 l . l E - 1 6 PORV RE 1

7 .12

Table 7 .3 S e n s i t i v i t y / U n c e r t a i n t y R esul t s S u u a ry (continued)

C la ss P a ra n e te x Type Nu V ariance P a r t i a l C o n tr ib u t io n Branch: #

FREQ BP FWS 1 .4E-03 5.1E-06 1.2E-06 7.3E-18

FREQ BP FWS 3 .4E-03 3.0E-05 3.6E-06 4.0E-16

FREQ BP FWS l.O E-01 2.6E-02 9.4E-09 2.3E-18

FREQ BP ECC 1.3E-03 4.4E-06 2.9E-07 3.7E-19

FREQ BP ECC 4 .OE-05 4.2E-09 O.OE+OO O.OE+OO

FREQ BP PPC 1 .OE-05 2.6E-10 5.7E-07 8.4E-23

FREQ BP PPC 5.0E-01 6.5E-01 4.2E-09 1 .2E-17

FREQ BP PPC 2.0E -02 l.OE-03 l . l E - 0 6 1.2E-15

FREQ BP PPC 2.7E -02 1.9E-03 4.6E-07 4.0E-16

FREQ BP RES 3.2E+00 1.2E-05 4.6E-10

FREQ BP WF l.O E-02 2.6E-04 6.0E-05 9.4E-13

FH RHOFLAW 1 .OE+00 3 .6E+01 4.5E-06 7.3E-10

FH FLIJENCE I.IE+OO l . l E - 0 1 l . l E - 0 5 1.3E-11

FN CD% 2.9E-01 6.3E-04 1.7E-04 1.8E-11

FH NI% 5.5E-01 O.OE+OO O.OE+OO O.OE+OO

FH RTNDTO -7.0E+00 8.1E+01 4.7E-07 1.8E-11

FH DELRTNDT 9.0E+01 8.8E+01 4.7E-07 1.9E-11

FH KIC NA 2.3E -02 5.6E-05 7.1E-11

FH KIA NA l.O E-02 9.9E-07 9.8E-15

IB HTCOEFF NA 6.3E-02 1.8E-06 2.0E-13

TH TEHP NA 7.8E+02 1.4E-06 1.5E-09

TH PRESS NA 1.2E-01 7.7E-07 6.9E-14

TOTAL = 2 . 5 X 10,-9

7 . 13

Table 7 .4 C onfidence i n t e r v a l s f o r a lognorm al assnm ption

Confidence Level F a c to r Lover Bound Upper Bound

68% 9 .0 5.0E-07 4.1E-05

95% 82 5.5E-08 3.7E-04

99.7% 737 6.1E-09 3.3E-03

7 .14

The second l a r g e s t c o n t r i b u t i o n (29%) to the o y e r a l l u n c e r t a in t y i s t h a t

a t t r i b u t a b l e to th e f law d e n s i t y in th e w eld . Once a g a in , th e magnitude o f

the c o n t r i b u t i o n i s due t o a la rg e p a r t i a l d e r i v a t i v e coupled w ith a la rg e

p a ram e te r u n c e r t a i n t y .

Ranking t h i r d (18%) as a sou rce o f u n c e r t a i n t y i s th e c o n t r i b u t i o n due to

th e r e s i d u a l t r a n s i e n t u n c e r t a i n t i e s . T h is c o n t r i b u t i o n i s a t t r i b u t a b l e

t o two f a c t o r s . F i r s t , th e v a r ia n c e e s t im a te d f o r the b ranch p o in t s i s

l a rg e as a r e s u l t o f th e c o n s e rv a t iv e p rocedu re u t i l i z e d to o b ta in i t .

Second, th e p a r t i a l d e r i v a t i v e c a l c u l a t e d f o r t h i s p a ram e te r in c o rp o ra te s

th e c o n d i t i o n a l p r o b a b i l i t y of f a i l u r e [P (F /E ^)] c a l c u l a t e d f o r th e d e f a u l t

t r a n s i e n t ( the h ig h e s t c o n d i t io n a l f a i l u r e p r o b a b i l i t y o b ta in e d f o r any of

the t r a n s i e n t s ) .

F i n a l l y , i t i s u s e f u l t o sum th e c o n t r i b u t i o n s o f th e v a r io u s p a ram e te rs

i n t o t h r e e c l a s s e s r e p r e s e n t in g th e th r e e m ajor in f lu e n c e s on f requency o f

v e s s e l f a i l u r e (ev en t f req u e n c y , f r a c t u r e m echan ics , or the rm al hydrau­

l i c s ) . This breakdown i s g iven in Tab le 7 .5 .

7 .15

Table 7 .5 Uncerta in ty co n tr ib u t io n by major parameter c l a s s i f i c a t i o n

C l a s s i f i c a t i o n C o n t r ib u t io n C o r r e la t io n s

Event frequency 1.4E-10 0.056

F r a c tu r e m echanics 8.7E-10 0.34

Thermal h y d r a u l i c s 1.5E-09 0 .60

T o ta l 2 .5E -9 1 .00

7 .16

8 .0 CONCLUSIONS AND RECOMMENDATIONS

6 . F. F lanagan , Oak Ridge N a t io n a l L ab o ra to ry

8 .1 I n t r o d u c t io n

T his c h a p te r c o n s i s t s o f s p e c i f i c and g e n e ra l c o n c lu s io n s which were drawn

from the r e s u l t s o f th e r e p o r t and a l s o from v a r io u s a s p e c t s o f the

a n a l y s i s . In a d d i t i o n . S e c t io n 8 .3 d i s c u s s e s a re a s o f the r e p o r t t h a t

r e q u i r e f u r t h e r s tudy and developm ent i f a s im i l a r P r e s s u r i z e d Thermal

Shock (PTS) a n a l y s i s were to be perfo rm ed on o th e r n u c le a r p l a n t s .

8 .2 C onc lus ions from t he Oconee-1 S tudv

8 .2 .1 Oconee-1 System F e a tu re s and P roposed System CSianges

Major system s r e l a t e d to th e Oconee-1 PTS a n a l y s i s were d e s c r ib e d in (3iap-

t e r 2 . From th e a n a l y s i s i t became a p p a re n t t h a t two of th e Oconee-1 sy s­

tem f e a t u r e s p la y major r o l e s i n re d u c in g th e th ro u g h - th e -w a l l c ra c k (TVC)

r i s k :

(1) The v e n t v a lv e s i n th e B&V r e a c t o r v e s s e l minimize therm al s t r a t i ­

f i c a t i o n in the downcomer r e g io n when p r im ary loop flow s t a g n a t e s .

(2) The steam g e n e ra to r a t Oconee-1 has a h ig h l e v e l t r i p f e a t u r e

( i n s t a l l e d by Duke Power) which p re v e n t s o v e r f i l l on MFW. W ithout such a

f e a t u r e , the o v e r a l l r i s k o f a TWC in c r e a s e s by 35%. T his in c re a s e was

based on the assum ption t h a t main fee d w a te r flow cou ld be s u s ta in e d a f t e r

8.1

the steam g e n e r a to r f i l l e d w i th w a te r . I t ap p ea rs t h a t t h e r e a re some

a s p e c t s o f th e d es ig n o f th e system t h a t m ight i n v a l i d a t e t h i s assnm ption

and th u s reduce the in c re a s e in TWC r i s k . One o f th e se a s p e c t s i s t h a t the

main fe e d w a te r pnmps a re d r iv e n by steam tu r b in e s which e x t r a c t t h e i r steam

from the lo w es t p o in t a t th e end o f th e steam l i n e . Water e n t r a in e d in the

steam would r e s u l t in l o s s o f t u r b i n e power to th e fe ed w a te r pumps and sub­

s e q u e n t ly r e s u l t in a t e rm in a t io n o f th e feed w ate r e v e n t . Secondly , the

w a te r dynamics i n th e steam l i n e m ight le a d to f a i l u r e i n th e steam l i n e

w hich would p ro b a b ly r e s u l t in a blowdown in s t e a d o f an o v e r fe e d . These

e f f e c t s were n o t an a ly zed i n t h i s s tu d y and th u s canno t be q u a n t i f i e d .

Two system changes have been examined which cou ld le a d to a d d i t i o n a l red u c ­

t i o n o f th e r i s k o f TWC:

(1) The f i r s t change in v o lv e s th e h e a t in g o f the h ig h - p r e s s u r e i n j e c ­

t i o n (HPI) w a te r by SO°F. S ince com plete mixing o ccu rs d u r in g most o f the

t r a n s i e n t s i n O conee-1, th e a c t u a l downcomer w a te r te m p e ra tu re i s e s t im a te d

t o in c r e a s e l e s s th an lO^^F (w e ll w i th in th e e s t im a te d te m p e ra tu re u n ce r­

t a i n t y o f t h i s s tu d y ) , th e re b y p ro v id in g n e g l i g i b l e b e n e f i t .

(2) A second system change i s a m o d i f ic a t io n o f th e c o n t ro l o r opera ­

t i o n a l p ro c e d u re s so as t o l i m i t th e r e p r e s s u r i z a t i o n o f th e p r im ary system

d u r in g an o v e rc o o l in g t r a n s i e n t . I f such a system were 100% e f f e c t i v e , the _»T

r i s k o f a TWC would d e c re a se a t l e a s t a f a c t o r o f 14 to 3 .2 x 10 /RY.

T h is cou ld most e a s i l y be accom plished by a p p r o p r ia te t h r o t t l i n g o f the

HPI. (T h is t h r o t t l i n g was n o t ta k e n in t o accoun t i n th e Oconee-1 s tu d y . )

I t shou ld be n o te d t h a t Duke Power i s c u r r e n t l y im plem enting the

8.2

a n t i c i p a t e d t r a n s i e n t o p e r a t in g g u id e l in e (ATOG) program which in c lu d e s

o p e r a to r a c t io n to l i m i t r e p r e s s u r i z a t i o n as p a r t o f the response to o v e r -

c o o l in g e v e n t s .

8 . 2 .2 A cciden t Sequence A n a ly s is

The a c c id e n t sequence a n a l y s i s i s d is c u s s e d in C hap te rs 3 and 6 o f t h i s

r e p o r t and s e v e r a l s i g n i f i c a n t c o n c lu s io n s can be drawn:

(1) The r e s u l t s show t h a t th e r i s k p r o f i l e i s dom inated by the “r e s i ­

dua l r i s k . " * The t h r e e r e a so n s f o r t h i s la rg e r e s i d u a l r i s k a re as f o l ­

lows: (a) No o p e r a to r a c t i o n t r e e s were a s s ig n e d to any sequence in th e

“r e s i d u a l r i s k " c a te g o ry ; th u s th e human e r r o r p r o b a b i l i t y was 1 .0 . (b) A

s in g le seve re th e rm a l - h y d r a u l ic t r a n s i e n t was a s s ig n e d to each even t

sequence in the r e s i d u a l c a te g o ry , which r e s u l t e d in a c o n s ta n t c o n d i t io n a l —3

p r o b a b i l i t y o f TWC o f 5 .4 x 10 . (c ) There was a l a rg e number o f even t

sequences ( s e v e r a l m i l l i o n ) which were lumped i n t o th e " r e s id u a l r i s k "

c a te g o r y . T h e re fo re , i t i s ou r o p in io n t h a t more s e l e c t i v e te ch n iq u es

sh o u ld be c o n s id e re d f o r a s s ig n in g t r a n s i e n t s to the r e s i d u a l r i s k c a te g o ry

i n f u tu r e s t u d i e s .

(2) In a s s e s s in g th e o v e r a l l r i s k o f TWC i n Oconee-1, no in d iv id u a l

sequence , when combined w i th th e c o n d i t io n a l p r o b a b i l i t y o f a TWC, had a

f req u en cy l a r g e r than 6 x 10 /RT.

(3) The steam l i n e b re a k i n i t i a t o r s were found to be the most impor­

t a n t c o n t r i b u t o r s to r i s k (second o n ly to the r e s i d u a l in t o t a l r i s k

c o n t r i b u t i o n s ) .

*A11 even t sequences whose f r e q u e n c ie s were l e s s th a n 10 ^/RY were lumped i n t o a c a te g o ry c a l l e d " r e s id u a l r i s k . "

8.3

(4) Of the sequences analyzed* th o se v i t h h ig h f requency o f o ccu rren c e

have low TWC c o n d i t i o n a l p r o b a b i l i t y . Conversely* e v e n ts which have h igh

TWC c o n d i t i o n a l p r o b a b i l i t y have low f req u en cy o f o c c u rre n c e .

8 .2 .3 F r a c tu r e Mechanics A n a ly s is

From the f r a c t u r e m echanics a n a l y s i s in C hap ter 5* s e v e r a l c o n c lu s io n s can

be drawn:

(1) The a x i a l welds (Weld Numbers SA1073* SA1430* and SA1493) dominate

the c o n t r i b u t i o n to th e TWC c o n d i t i o n a l p r o b a b i l i t y . Assuming th e same

flaw d e n s i t y th ro u g h o u t th e b e l t l i n e r e g io n o f the v e s se l* th e c i rc u m fe re n ­

t i a l welds would add ap p ro x im a te ly 5% to P (F /E ) and the base m a te r i a l

a p p ro x im a te ly 30%.

(2) Aside from the f law d e n s i ty * P (F /E ) i s by f a r most s e n s i t i v e to

u n c e r t a i n t i e s in th e te m p era tu re o f th e c o o la n t i n th e downcomer and l e a s t

s e n s i t i v e to the f l u i d - f i l m h e a t t r a n s f e r c o e f f i c i e n t a t the v e s s e l in n e r

s u r f a c e and the p rim arjr-system p r e s s u r e .

(3) A r e d u c t io n in the f lu e n c e r a t e cou ld have a s i g n i f i c a n t im pact on

th e r i s k o f a TWC* b u t a c o s t / b e n e f i t a n a l y s i s i s needed .

(4) Improved i n - s e r v i c e in s p e c t io n fo llo w ed by r e p a i r o f a l l f law s

t h a t a re found cou ld reduce the PTS r i s k s i g n i f i c a n t l y * b u t com plete r e p a i r

and p r e c i s e d e t e c t i o n o f f law s a re d i f f i c u l t w i th t o d a y 's te ch n o lo g y .

8.4

(5) A nnealing the p r e s s u r e v e s s e l would s i g n i f i c a n t l y reduce the PTS

r i s k , b u t the c o s t and u n c e r t a i n t y re g a rd in g t e c h n ic a l f e a s i b i l i t y p rob ab ly

r e n d e r t h i s a l a s t r e s o r t f i x t o th e PTS problem .

(6) The in c lu s io n o f WPS in th e FM a n a l y s i s reduces P(F /E) by s e v e ra l

o rd e r s o f m agnitude fo r many, b u t n o t a l l , o f the id e a l i z e d t r a n s i e n t s .

Because of concerns over th e a p p l i c a b i l i t y o f WPS under a c tu a l t r a n s i e n t

c o n d i t io n s , i t was n o t in c lu d e d i n th e e s t im a te o f (TWC), b u t t h i s does

n o t mean t h a t c o n d i t io n s f o r which WPS would be e f f e c t i v e cannot be expec­

te d t o o c c u r .

(7) L im it in g th e p r im ary -sy s te m p r e s s u r e to app ro x im ate ly 7 MPa (1000

p s i ) d u r in g r e p r e s s u r i z a t i o n f o r th o se t r a n s i e n t s t h a t would o th e rw ise

ex p e r ie n c e h ig h e r p r e s s u r e s reduced P (F /E ) by as much as two o rd e rs o f mag­

n i tu d e f o r i n d i v id u a l t r a n s i e n t s .

(8) For many o f the t r a n s i e n t s , th e p r e d i c t e d f a i l u r e s o cc u r re d n ea r

the end o f th e assumed 2-h d u r a t i o n (see Appendix E ) . This i s approach ing

a c o ld o v e r p r e s s u r i z a t i o n s i t u a t i o n , and th u s ex ten d in g th e d u r a t io n o f the

t r a n s i e n t c o u ld s u b s t a n t i a l l y in c re a s e P (F /E ) . C onverse ly , i f th e d u r a t io n

were d e c re a se d , P (F /E) would be d e c re a se d .

8 .2 .4 U n c e r ta in ty and S e n s i t i v i t y A n a ly s is

The u n c e r t a i n t y and s e n s i t i v i t y a n a l y s i s r e p o r t e d in C hapter 7 i n d i c a te s

the fo l lo w in g :

8.5

(1) The im c e r t a i n t y in th e te m p e ra tu re o f th e downcomer f l u i d (±28^C)

dom inates the u n c e r t a i n t y in f re q u e n c y o f a TVC.

(2) The u n c e r t a i n t y in th e f law d e n s i t y i s th e l a r g e s t u n c e r t a i n t y of

any f a c t o r c o n s id e re d and r e s u l t s i n th e second l a r g e s t u n c e r t a i n t y c o n t r i ­

b u t i o n to th e TWC f req u en cy .

(3) The f a i l u r e o f the o p e r a to r to i s o l a t e th e steam g e n e r a to r du r in g

a steam l i n e b re a k r e p r e s e n t s , w ith th e e x c e p t io n o f th e f a i l u r e to

t h r o t t l e HPI, the l a r g e s t human e r r o r c o n t r i b u t i o n to th e f req u en cy o f a

TWC.

8 .2 .5 G eneral C onclusions

In a d d i t i o n to the s p e c i f i c c o n c lu s io n s drawn from the s p e c i f i c c h a p te r s o f

th e s tu d y , th e fo l lo w in g g e n e ra l s ta t e m e n t s can be made:

(1) Only minimal system i n t e r a c t i o n s , no e x t e r n a l e v e n ts ( f i r e s ,

f l o o d s , e a r th q u a k e s , o r s ab o tag e ) and no in a d v e r te n t o p e r a to r a c t io n s were

c o n s id e re d i n the Oconee-1 s tu d y . The impact o f th e se e f f e c t s on th e f r e ­

quency of a TWC cannot be e s t im a te d e i t h e r q u a l i t a t i v e l y o r q u a n t i t a t i v e l y

w i th o u t f u r t h e r a n a l y s i s .

(2) The b e s t e s t im a te o f th e f req u en cy o f a TWC (4 .5 x 10~^/RY) i s

sm all* when compared to th e p roposed s a f e t y g o a l . T h is number i s about a

*This assumes t h a t th e c o n d i t io n a l p r o b a b i l i t y o f co re m e l t , g iv e n a TWC, i s 1 .

8.6

f a c t o r of 10 l e s s th an th e dominant core m e l t p r o b a b i l i t i e s c a l c n l a t e d in

p l a n t - s p e c i f i c PRAs, which im p l ie s t h a t PTS i s a sm all c o n t r i b u to r to

o y e r a l l r i s k o f co re m e l t .

(3) The b e s t e s t im a te o f th e f req u en cy o f a IVC based on in fo rm a tio n

u t i l i z e d in t h i s r e p o r t i s n e a r l y s ix t im es l a r g e r than th e upper l i m i t

(8 .5 X 10 ^/RY) r e p o r t e d i n the B&V Owners Group S tudy .*

8 .3 Areas R eq u ir in g F u r th e r Studv and Development

8 .3 .1 Human R e l i a b i l i t y

The method used f o r q u a n t i f i c a t i o n o f human e r r o r in th e Oconee-1 s tu d y

c l e a r l y needs improvement. A more s o p h i s t i c a t e d te ch n iq u e was adopted f o r

l a t e r s tu d i e s perform ed f o r the C a lv e r t C l i f f s - 1 and H. B. Robinson-2

p l a n t s . As in a l l PRAs. t h i s s u b je c t d e se rv e s c o n s id e ra b le a t t e n t i o n . The

o p e r a to r o b v io u s ly p la y s a s i g n i f i c a n t r o l e i n th e p ro g re s s o f a PTS

sequence , b u t because o f th e s i m p l i s t i c t r e a tm e n t in t h i s s tu d y , th e c a lc u ­

l a t e d s e n s i t i v i t y o f th e TWC to o p e ra to r a c t i o n i s p ro b ab ly n o t as l a rg e as

would occur i f a more s o p h i s t i c a t e d approach to htiman a c t i o n were to be

im plem ented.

8 . 3 .2 System I n t e r a c t i o n s

The approach used to e v a lu a te system i n t e r a c t i o n s f o r t h i s s tu d y was a l s o

s i m p l i s t i c and no system i n t e r a c t i o n s were i d e n t i f i e d in the Oconee-1

•B&W Owners Group, 'P r o b a b i l i t y E v a lu a t io n o f P r e s s u r i z e d Thermal Shock Phase I , " p p . 2 -3 , BAW-1791 (June 1983).

8.7

a n a l y s i s . More in - d e p th a n a ly se s f o r th e C a lv e r t C l i f f s - 1 and H. B.

Robinson-2 s tu d ie s d id i n d i c a t e the e x i s t e n c e o f system i n t e r a c t i o n s , which

cou ld prove im p o r tan t to PTS sequences i n th e s e p l a n t s .

8 .3 .3 E x te rn a l E vents

The freq u en cy o f e x t e r n a l e v e n ts and t h e i r im pact on PTS was exc luded from

th e Oconee-1 s tu d y and from the C a lv e r t C l i f f s - 1 and H. B. Robinson-2 s tu ­

d i e s as w e l l . S ince many o f th e s i g n i f i c a n t sequences i n Oconee-1 in v o lv e

m u l t i p l e f a i l u r e s , i t i s p o s s i b l e t h a t an e x t e r n a l even t cou ld in c re a s e the

f req u en cy o f the dominant sequences by e l im i n a t in g th e randomness o f the

f a i l u r e s . However, most e x t e r n a l even t a n a ly s e s a r e found to a f f e c t the

c o o l in g system s and c o n t r o l system s o f r e a c t o r s and one m ight ex p ec t an

u n d e rc o o l in g even t due to a e x t e r n a l h a z a rd to be more p r e v a l e n t th a n an

o v e rc o o l in g e v e n t .

8 .3 .4 F lood ing

L ate in the s tu d y , the s u b je c t o f f lo o d in g o f th e r e a c t o r c a v i ty su r ro u n ­

d ing the v e s s e l was d i s c u s s e d ; however, n e i t h e r time n o r money was a v a i l a ­

b l e to an a ly ze t h i s s c e n a r io .

8 .3 .5 T herm al-H ydrau lic Modeling

I t i s c l e a r t h a t the th e rm a l -h y d ra u l ic (T-H) m odeling r e q u i r e s c o n s id e ra b le

e f f o r t in b u i ld in g and v a l i d a t i n g th e p r im ary and secondary m odels , e s p e c i ­

a l l y in c o n ju n c t io n w i th an i n t e g r a t e d c o n t r o l system such as ap p ea rs in

th e Oconee-1 r e a c t o r . Even when th e p l a n t system s a re p u rp o r te d to he

8.8

c o r r e c t l y modeled, the RELAP and TRAC codes do no t g ive i d e n t i c a l answ ers,

and in one c a s e , the p r e d i c t e d downcomer te m p era tu re s d i f f e r e d by more than

140°F. xhe e f f e c t o f modeling shou ld be c a r e f u l l y ad d re s se d whenever a PTS

s tudy i s done .

8 . 3 .6 Decay Heat Assumptions

Because o f the v en t v a lv e s in O conee-1, loop s t a g n a t io n does n o t appear to

be a problem f o r l o s s - o f - c o o l a n t a c c id e n t s (LOCA). However, shou ld a LOCA

occur a t h o t s tandby fo l lo w in g an ex ten d ed shutdown, s t a g n a t io n i s l i k e l y

to o ccu r and m ight l e a d to low downcomer te m p e ra tu re s . A lso , w ith o u t a

sou rce o f decay h e a t , a steam l i n e b re a k a t ho t s tandby cou ld cause s i g n i ­

f i c a n t l y lower downcomer te m p e ra tu r e s . On the o th e r hand, the frequency of

th e s e e v e n ts i s lower than s i m i l a r e v e n ts a t f u l l power, so th e e f f e c t on

th e t o t a l r i s k shou ld be examined in f u t u r e s t u d i e s .

8 .3 .7 D u ra t io n o f C a lc u la te d T r a n s ie n t s

Throughout the s tu d y the T-H a n a l y s i s was a r b i t r a r i l y te rm in a te d a f t e r two

h o u rs , the u n d e r ly in g assum ption be ing t h a t some o p e r a to r a c t io n would be

ta k e n by t h a t time to m i t i g a t e th e e v e n t . However, fo r n o n - i s o l a t a b l e

e v e n ts (LOCAs and steam l i n e b r e a k s ) , t h i s may n o t be a r e a l i s t i c assump­

t i o n . F u r th e rm o re , i t ap p ea rs t h a t f o r s e v e r a l t r a n s i e n t s a l a rg e p e rcen ­

tag e o f TWCs occu r a t the two hour l i m i t . The e f f e c t o f th e two hour l im i ­

t a t i o n m e r i t s f u r t h e r a n a l y s i s i n l i g h t o f the r e l a t i v e im portance of the

cho ice o f t h i s time p e r io d .

8.9

8 . 4 S n m n m r v

A lthough t h i s s tu d y does n o t co m p le te ly e l im in a te p r e s s u r i z e d the rm al shock

as an u n re s o lv e d s a f e ty i s s u e f o r th e Oconee-1 p l a n t , i t does p ro v id e a

tho rough s tu d y o f the e f f e c t o f v a r io u s p o t e n t i a l o v e rc o o l in g t r a n s i e n t s on

th e r e a c t o r v e s s e l . I t i s r e a l i z e d t h a t much o f what i s s t a t e d i n t h i s

r e p o r t was known to some e x te n t and i n p iecem eal f a s h io n by v a r io u s t e c h n i ­

c a l s p e c i a l i s t s p r i o r to th e s tu d y . However, by i n t e g r a t i n g th e d i s c i ­

p l i n e s o f p r o b a b i l i s t i c r i s k a n a l y s i s , th e rm a l-h y d ra u l ic a n a l y s i s , and

f r a c t u r e m echan ics , and by a d o p t in g a c o n s i s t e n t te ch n iq u e o f a s s e s s in g

u n c e r t a i n t i e s and s e n s i t i v i t i e s a c r o s s th e s e d i s c i p l i n e s , a c l e a r e r under­

s ta n d in g o f the t o t a l a s p e c t o f th e p r e s s u r i z e d the rm al shock problem has

r e s u l t e d . In p a r t i c u l a r , the u n c e r t a i n t y a n a l y s i s , a l th o u g h f a r from p e r ­

f e c t , r e p r e s e n t s an a t te m p t to adop t a c o n s i s t e n t and m a th e m a t ic a l ly sound

a n a l y s i s o f the problem . Such an a n a l y s i s shou ld be a r e q u i s i t e f o r any

f u tu r e p r e s s u r i z e d the rm al shock s tu d y perfo rm ed by NRC or a u t i l i t y . Even

w i th the d e f i c i e n c i e s o u t l i n e d i n S e c t io n 8 .3 , th e r e s u l t s o f t h i s s tudy

sh o u ld be o f use to b o th NRC and Duke Power Company in r e s o lv i n g the

p l a n t - s p e c i f i c a s p e c t s o f p r e s s u r i z e d the rm al shock. The approach ta k e n in

th e Oconee-1 s tu d y (w ith m o d i f i c a t io n s ) shou ld p ro v id e a b a s i s f o r f u tu r e

p l a n t - s p e c i f i c p r o b a b i l i s t i c r i s k a s se s sm e n ts o f p r e s s u r i z e d the rm al shock.

8.10

APPENDIX A

EVENT TREES

The o o a p n te r iz e d even t t r e e s a re e x te n s iv e and to o la rg e to be in c lu d ed in

t h i s r e p o r t . They a re a v a i l a b l e from George Flanagan* E n g in ee r in g P h y s ic s

and M athem atics D iv is io n , B u ild in g 6025, Oak Ridge N a tio n a l L ab o ra to ry ,

P .O. Box X, Oak R idge , TN 37831.

Three s e t s o f d a ta a re p r e s e n te d in t h i s appendix ; S e c t io n A .l i s a

log o f sequences by i d e n t i f i c a t i o n number and frequency f o r system s t a t e

t r e e b ran ch p o i n t s . S e c t io n A.2 i s a log of sequences summed by system

s t a t e c a te g o ry , and S e c t io n A.3 r e l a t e s th e com bination o f end s t a t e

f r e q u e n c ie s o f S e c t io n A.2 o p e r a to r a c t i o n p r o b a b i l i t i e s and f r a c t u r e ^

m echanics p r o b a b i l i t i e s o f Table 6 . 1 .

A .l

A .l Sequence* by I d c a t i f i c t t i o n Nuabor »n4 Frequ^pcy^ System S U t e Tree

Bynncb Pc iit*

A.2

-SYSTEH STftTE BRflNCHES- -CATE60RIES-REC IN IT SEQ* SPC FNS ECC PPC EFRE8 SPC FHS ECC PPC

1 RT 6556 I 24 1 1 4 .8E + 00 0 0 0 02 RT 6841 1 25 1 1 1 .4 E -0 1 0 1 0 0

RT 7148 1 26 2 8 2 .0 E -0 4 0 •J 0 0RT 7149 1 26 n 9 5 .5 E -0 6 0 •i 0 1

5 RT 7150 I 26 nL 10 1 .3 E -0 5 0 3 0 ■-!

6 RT 7152 1 26 ■•y 12 2 .3 E -0 5 0 3 0 07 RT 7153 1 26 •7i. 13 1 .4E -C 6 0 •3 0 2a RT 7433 1 27 3 1 .2 E -0 5 0 7-j 0 09 RT 7437 1 n - T 2 12 1 .3 E -0 6 0 3 0 0

10 RT 7703 1 23 1 8 6 .6 E -0 4 0 4 0 011 RT 7704 1 28 1 9 1 .8 E -0 5 0 4 0 112 RT 7705 1 28 1 10 4 .2 E -0 5 0 4 0 213 RT 7706 1 23 1 11 1 .2 E -0 6 0 4 0 n

14 RT 7707 1 28 1 12 7 .5 E -0 5 0 4 0 015 RT 7708 1 23 1 13 4 .S E -0 6 0 4 0 n

L

16 RT 7988 I 29 1 8 1 .7 E -0 4 0 4 0 017 RT 7989 1 29 )i 9 4 .6 E -0 6 n 4 0 1l a RT 7990 1 29 1 10 l . l E - 0 5 0 4 0 z

19 RT 7992 1 29 1 12 1 .9 E -0 5 0 4 0 020 RT 7993 1 29 1 13 1 .2 E -0 6 0 4 0 221 RT 8238 1 30 n 8 5 .2 E -0 4 0 9 0 022 RT 8289 1 30 n

L 9 1 .4 E -0 5 AV

•-) 0 i23 RT 8290 1 30 z 10 3 .3 E -0 5 (I T

L, 024 RT 8 2 9 2 1 30 2 12 5 .9 E -0 5 0 9 0 025 RT 3293 1 30 n

L 13 3 .8 E -0 6 0 0 n

26 RT 8551 1 71•J I 1 1 1 .4 E -0 2 0 I 0 0

27 RT 8858 1 32 2 8 2 .0 E -0 5 0 ■j 0 023 RT 3360 1 t n

■JL. 2 10 1 .3 E -0 6 0 ■j 0 £.

29 RT 8362 1 32 L 12 2 .3 E -0 6 0 ■j 0 030 RT 9143 1 33 3 1 .2 E -0 6 0 A 0 031 RT 9413 1 34 1 B 6 .6 E -0 5 0 4 0 032 RT 9414 1 34 i 9 1 .3 E -0 6 0 4 0 4

33 RT 9415 I 34 1 10 4 .2 E -0 6 f*t 4 0 nL

34 RT 9417 1 34 4i 12 7 .5 E -0 6 0 4 0 0

35 RT 9698 1 7 5 4I 8 1 .7 E -0 5 A 4 0A

36 RT 9700 1 35 1 10 1 .1E-Q 6 'v 4 nV ni .

37 RT 9702 1 35 1 12 1 .9 E -0 6 0 4 i) 038 RT 9998 1 36 2 3 1 .2 E -0 6 0 •T ( j 039 RT 10261 1 j / 1 1 1 .4 E -0 1 0 0 040 RT 10568 1 38 n

L 8 2 .0 E -0 4 0 • j 0 041 RT 10569 1 38 9 5 .5 E -0 6 0 • j 0 142 RT 10570 1 33 n, 10 1 .3 E -0 5 0 3 0 243 RT 10572 1 38 12 2 .3 E -0 5 0 3 0 044 RT 10573 1 38 n

L 13 1 .4 E -0 6 0 7 0 245 RT 10853 1 39 1 8 1 .2 E -0 5 0 3 0 046 RT 10857 1 39 1 12 1 .3 E -0 6 0 7 0 047 RT 11123 1 40 1 8 6 .6 E -0 4 0 4 0 048 RT 11124 1 40 I 9 1 .8 E -0 5 0 4 0 147 RT 11125 1 40 1 1 0 .4 .2 E -0 5 0 4 0 n

L

A.3

-3YSTEH STATE 8RANCHES- --CATEGQRIES-REC IMIT SE8* SPC FRS ECC PPC EFRES SPC F»S ECC PPC

50 RT 11126 1 40 I 11 1 .2 E -0 6 0 4 0 n

5 i RT 11127 1 40 1 12 7 .5 E -0 5 0 4 0 05 2 RT 11123 1 40 1 13 4 .8 E -0 6 0 4 0 n

5 3 RT 11408 1 41 1 8 1 .7 E -0 4 0 4 0 054 RT 11409 1 41 1 9 4 .6 E -0 6 0 4 0 L55 RT 11410 1 41 1 10 l . l E - 0 5 0 4 0 256 RT 11412 1 41 1 12 1 .9 E -0 5 0 4 0 057 RT 11413 1 41 <i 13 1 .2 E -0 6 0 4 0 T

58 RT 74973 2 95 nL. 3 3 .0 E -0 1 1 0 0 0

59 RT 74979 n 95 0L. 9 8 .3 E -0 3 1 0 0 1

60 RT 74930 2 95 0 10 1 .9 E -0 2 1 0 0 261 RT 74981 n

L 95 nL 11 5 .3 E -0 4 1 0 0 2

6 2 RT 74982 L 95 0 12 3 .4 E -0 2 1 0 0 06 3 RT 74983 1 95 n 13 2 .2 E -0 3 1 0 0 T4k

64 RT 74984 2 95 2 14 l .O E -0 4 I 0 0 065 RT 74985 2 95 15 6 .5 E -0 6 1 A 0 n

L

66 RT 74993 r\ 95 3 3 3 .9 E -0 4 1 0 1 0

67 RT 74994 nL 95 3 9 l . l E - 0 5 I 0 1 1

68 RT 74995 «/ 95 • j 10 2 .5 E -0 5 f

i 0 1 TL.

69 RT 74997 2 95 3 12 4 .4 E -0 5 51 0

70 RT 74998 / 95 3 13 2 .S E -0 6 1i

A 4i

■7

71 RT 75263 2 96 2 3 5 .1 E -0 4 1 0 0

72 RT 75264 2 96 nL 9 1 .4 E -0 5 1 • j 0 1

73 RT 75265 •y 96 n 10 3 .3 E -0 5 I 3 0 2

74 RT 75267 L 96 2 12 5 .3 E -0 5 I ‘j 0 0

75 RT 75268 n 96 nL 13 3 .7 E -0 6 1 0 L

76 RT 75548 2 97 1 8 3 .0 E -0 5 I 0 077 RT 75550 97 •) 10 1 .9 E -0 6 1 i

ClV

nL

78 RT 75552 2 97 2 12 3 .4 E -0 6 1L 0 0

79 RT 75833 98 2 8 1 .7 E -0 3 I 4 0 080 RT 75834 2 98 2 9 4 .7 E -0 5 { 4 0 181 RT 75835 z 98 2 10 l . l E - 0 4 1 4 0

7

82 RT 75836 2 93 2 11 3 .0 E -0 6 1 0 L

83 RT 75337 98 2 12 1 .9 E -0 4 1 4 04*1

84 RT 75838 2 93 2 13 1 .2 E -0 5 I 0 2

85 RT 75848 L 98 3 8 2 .2 E -0 6 1 1 036 RT 76113 2 99 2 a 4 .3 E -0 4 1 4 0 087 RT 76119 n

L 99 nL 9 1 .2 E -0 5 i

I 0 188 RT 76120 2 99 0 10 2 .7 E -0 5 I 0

•y

89 RT 76122 •) 99 2 12 4 .8 E -0 5 1 4 0 0

90 RT 76123 2 99 2 13 3 .1 E -0 6 1 4 0 291 RT 76403 L 100 2 8 8 .9 E -0 3 1 1 0 092 RT 76404 1 100 2 9 2 .5 E -0 4 1 0 193 RT 76405 2 100 2 10 5 .7 E -0 4 1 1 0 294 RT 76406 2 100 2 11 1 .6 E -0 5 1 1 0 u

95 RT 76407 n 100 nL 12 l .O E -0 3 1 1 0 0

96 RT 76408 2 100 1 13 6 .5 E -0 5 1 1 0 297 RT 76409 L 100 2 14 3 .0 E -0 6 1 I 0 098 RT 76 4 1 8 1 100 3 8 1 .2 E -0 5 1 1 I 0

A .4

:c IN IT SE St--SYSTEtt STATE BRANCHES

SPC FHS ECC PPC EFRE8 SPC--CflTEBQRIES

FilS ECC PPC

393 RT 1760755 TTit 95 n

i. 10 1 .7 E -0 5 1 0 0 23 94 RT 1760757 37 95 2 12 3 .1 E -0 5 L 0 0 0395 RT 1760758 37 95 13 2 .0 E -0 6 ti 0 0 7396 RT 1761608 37 98 n 8 1 .5 E -0 6 I 4 0 0397 RT 1762173 37 100 n

L 8 a . lE - 0 6 I I 0 0398 RT 1767373 37 120 2 3 8 .1 E -0 6 1 0 0 0399 RT 1808918 38 95 2 8 6 .0 E -0 5 3 0 0 0400 RT 1808919 38 95 2 9 1 .6 E -0 6 0 0 0 1401 RT 1808920 38 95 n

L 10 3 .8 E -0 6 T■i 0 0 •T

402 RT 1308922 38 95 'y 12 6 .3 E -0 6 3 0 0 0403 RT 1810343 38 100 8 1 .8 E -0 6 1 0 0404 RT 1816043 38 120 8 1 .8 E -0 6 •j 0 0 0405 RT 1857083 39 95 n 8 3 .0 E -0 5 4 0 0 0406 RT 1357085 39 95 2 10 1 .9 E -0 6 4 0 0 T

407 RT 1857037 39 95 12 3 .4 E -0 6 4 0 0 0408 RT 1905248 40 95 3 6 .7 E -0 6 T 0 0 040? RT 2318476 49 24 1 1 4 .3 E -0 4 (S 0 0 0410 RT 2318761 49 25 1 1 1 .3 E -0 5 0 1 0 0411 RT 2320471 49 31 1 1 1 .3 E -0 6 0 1 0 0412 RT 2322131 4 ? 37 iL 1 1 .3 E -0 5 V G V 0i l 3 RT 2336393 50 95 i* 8 2 .7 E -0 5 1 0 0 0414 RT 2386900 50 95 "J 10 1 .7 E -0 6 1 0 0 2415 RT 2 366902 50 95 n 12 3 . lE -0 6 1 0 0 0416 RT 2511136 53 24 1 1 4 .3 E '0 5 0 0 0 0417 RT 2511421 53 25 I 1 1 .4 E -0 6 0 1 0 Au

418 RT 2514841 uO 37 1 1 1 .4 E -0 6 0 0 0 0419 RT 2579553 54 95 3 3 .0E -0-6 1 0 0 0420 RT 2916713 61 95* z. 3 -Z.TE-OS 11. 0 0 nV421 RT 2916715 61 95 n

L 10 1 .7 E -0 6 1 0 0TL

422 RT 2916717 61 95 'y 12 3 .1 E -0 6 1 0 0 0423 RT 2964878 62 95 ly 8 6 .0 E -0 6 0 0 0

424 RT 3109373 65 95 2 3 i .0 E " 0 6 1 0 0 0425 RT 6364336 133 24 1 1 4 .5 E -0 3 0 0 0426 RT 6364621 133 25 1 1 1 .3 E -0 4 0 1 0 0427 RT 6366331 133 31 1 1 1 .3 E '0 5 1 0 0428 RT 6363041 1 37 1 1 1 .3 E -0 4 0 0 0 0429 RT 6432758 134 95 -T

L 3 2 .8 E -0 4 1 ) 0 0430 RT 6432759 134 95 2 9 7 .7 E -0 6 1 0 0 1431 RT 6432760 134 95 10 l .B E -0 5 0 0 2432 RT 6 432762 134 95 2 12 3 .2 E -0 5 I 0 0 0433 RT 6432763 134 95 2 13 2 .0 E -0 6 1 0 0 7434 RT 6433613 134 98 2 8 1 .6 E -0 6 1 4 0 0435 RT 6434183 134 100 n

L 8 3 .3 E -0 6 1 1 0 0436 RT 6439883 134 120 2 3 8 .4 E -0 6 1 0 0 0437 RT 6480923 135 95 •y

L 3 3 .3 E -0 6 2 0 0 0438 RT 6914408 144 95 n

L 8 4 .4 E -0 4 6 0 0 0439 RT 6 914409 144 95 2 9 1 .2 E -0 5 6 0 0 1440 RT 6914410 144 95 2 10 2 .8 E -0 5 6 0 0 2441 RT 691 44 12 144 95 2 12 5 .0 E -0 5 6 0 0 0

A.5

--SYSTEM STATE BRANCHES— -CATE50RIES-EC INIT SEQt SPC FHS ECC PPC EFREB SPC FHS ECC PPC

99 RT 76422 2 100 3 12 1 .3 E -0 6 1 1 1 0100 RT 76638 2 101 2 8 1 .5 E -0 5 1 3 0 0101 RT 76692 n 101 2 12 1 .7 E -0 6 1 3 0 0102 RT 77258 n

L 103 2 8 5 .0 E - 0 5 1 0 0103 RT 77259 2 103 2 9 1 .4 E -0 6 4 0 1104 RT 77260 103 2 10 3 .2 E -0 6 1 4 0 2105 RT 77262 n

L 103 2 12 5 .7 E -0 6 1 4 0 0104 RT 77543 n

L 104 2 8 1 .3 E -0 5 1 4 0 0107 RT 77547 1 104 n 12 1 .4 E -0 4 1 4 0 0108 RT 77328 n 105 n

C 8 3 .9 E -0 5 f\L 0 0

109 RT 77829 n 105 n 9 l . l E - 0 6 1 2 0 I110 RT 77830 2 105 10 2 .5 E -0 6 1 n

L 0 Tu

111 RT 77832 2 105 12 4 .5 E -0 6 tyL 0 0

112 RT 792 53 / IU 110 ' I 8 9 .0 E -0 4 1 1 0 0

113 RT 79254 1 110 9 2 .5 E -0 5 1 1 0 1114 RT 79255 n

L 110 nC 10 5 *7 E -05 1 1 0 2

115 RT 79256 n 110 nL 11 1 .6 E -0 6 1 i

I 0 Tu

114 RT 79257 L, 110 nL 12 l .O E -0 4 1 1 0 0

117 RT 79258 n 110 •yL 13 4 .5 E -0 6 1 1 0 2

l i e RT 79268 2 110 3 1 .2 E -0 4 1 I 1 0119 RT 79538 n 111 1 8 1 .5 E -0 6 I • J 0 0120 RT 30108 n 113 A

L 8 5 .1 E -0 4 1 4 0 0121 RT 80393 n

L 114 •yL 8 1 .3 E -0 6 1 4 0 0

122 RT 32103 nL 120 L 8 9 .0 E -0 3 1 0 0 0

123 RT 82104 120 •y 9 2 .5 E -0 4 1 0 0 1124 RT 82105 n

L 120 2 10 5 .7 E -0 4 1 0 0 nL

125 RT 82104 120 11 1 .6 E -0 5 1 0 0 0

126 RT 32107 nL 120 *y

L 12 l.O E -0 3 1 0 0 0127 RT 82108 0 120 ry 13 4 .5 E -0 5 I 0 0 TL.

128 RT 32109 120 nL 14 3 .1 E -0 6 0 0 0

129 RT 82113 2 120 3 3 U 2 E -0 5 0 1 0130 RT 32122 n 120 T 12 1 .3 E -0 6 1 0 1 0131 RT 82388 o

L 121 0u 8 1 .5 E -0 5 1 •) 0 0132 RT 32392 •1 121 n

L 12 1 .7 E -0 4 1 3 0 0133 RT 82958 n 123 J 8 5 .1 E -0 5 1 4 0 0134 RT 32959 n

L 123 2 9 1 .4 E -0 6 1 4 0 I135 RT 32940 L

n ? >y 10 3 .2 E -0 4 1 4 0 2134 RT 32942 2 123 i. 12 5 .7 E -0 6 1 4 0 0137 RT 83243 fy 124 8 1 .3 E -0 5 1 4 0 0138 RT 83247 n

L 124 n 12 1 .4 E -0 6 1 4 0 0139 RT 123143 3 95 •J 3 3 .5 E -0 3 0 0 0 0140 RT 123144 3 95 'J 9 9 .3 E -0 5 n 0 0 1141 RT 123145 ■j 95 »y 10 2 .3 3 - 0 4 2 0 0 •y

L

142 RT 123146 3 95 2 11 6 .2 E -0 6 2 0 0 2143 RT 123147 3 95 L 1 2 4 .0 E -0 4 2 0 0 0144 RT 123148 3 95 2 13 2 .6 E -0 5 2 0 0 2145 RT 123149 3 95 n

L 14 1 .2 E -0 6 2 0 0 0144 RT 123158 3 95 3 8 4 .6 E -0 4 2 0 1 0147 RT 123428 J 96 2 8 6 .0 E -0 6 2 3 0 0

A. 6

--SYSTEH STATE BRANGHES- -CATEGQRIES-c INIT SEQt SPC FNS ECC PPC EFREQ SPC FWS ECC PPC

148 RT 123998 3 98 2 8 2 .0 E -0 5 2 4 0 0149 RT 124000 3 98 n

L 10 1 .3 E -0 6 4 0 nL

150 RT 124002 3 98 2 12 2 .3 E -0 6 2 4 0 0151 RT 124283 3 99 n

L 8 5 .0 E -0 6 2 0 0152 RT 124568 •J 100 7 3 l . l E - 0 4 n

L I 0 0153 RT 124569 3 100 L 9 2 .9 E -0 6 n

L 1 0 1154 RT 124570 3 100 •y 10 6 .7 E -0 6 n 1 0 2155 RT 124572 0 100 n

L 12 1 .2 E -0 5 2 1 0 0156 RT 127418 7■J 110 n

L 8 l . l E - 0 5 2 1 0 0157 RT 127422 3 110 L 12 1 .2 E -0 6 2 1 c 0158 RT 130268 3 120 2 8 l . l E - 0 4 0 0 0 0159 RT 130269 3 120 2 9 2 .9 E -0 6 2 0 1160 RT 130270 120 2 10 6 .7 E -0 6 0 A

L

161 RT 130272 7■j 120 a

L 12 1 .2 E -0 5 2 0 0 0162 RT 171308 4 95 8 2 .7 E - 0 4 1 0 0 0163 RT 171309 4 95 f\ 9 7 .5 E -0 6 I 0 0 I164 RT 171310 4 95 1 10 1 .7 E -0 5 1 0 0 2165 RT 171312 4 95 2 12 3 .1 E -0 5 1 0 0 0166 RT 171313 4 95 2 13 2 .0 E -0 6 1 0 0 A

L

167 RT 172163 4 98 n 8 1 .5 E -0 6 1 4 0 0168 RT 172733 4 100 n

L 8 8 .0 E -0 6 [ 1 0 0169 RT 178433 4 120 2 8 8 .1 E -0 6 I 0 0 0

170 RT 199216 5 24 1 1 4 .3 E -0 4 0 0 0 0171 RT 199501 5 25 1 1 1 .3 E -0 5 !) i

i 0 0172 RT 201211 5 31 1 I 1 .3 E -0 6 0 1 0 0173 RT 202921 5 37 1 1 1 .3 E -0 5 0 0 0 0174 RT 267638 6 95 2 8 2 .7 E -0 5 1 0 0 0175 RT 267640 6 95 n

L 10 1 .7 E -0 6 1 0 0 •7i.

176 RT 267642 6 95 nL 12 3 .1 E -0 6 1 0 A'.} 0

177 RT 536371 12 24 1 1 4 .4 E -0 3 0 c 0 0178 RT 536656 12 25 1 1 1 .3 E -0 4 0 1 0 0179 RT 538366 12 31 I 1 1 .3 E -0 5 0 1 0 n

V

180 RT 540076 12 37 1 1 1 .3 E -0 4 0 0 0 0181 RT 604793 13 95 L 8 3 .0 E -0 1 1 0 0 0182 RT 604794 13 95 n

L 9 3 .3 E -0 3 1 0 0 i

183 RT 604795 13 95 L 10 1 .9 E -0 2 1 0 0 0u184 RT 604796 13 95 n

L 11 5 .3 E -0 4 1 AV 0 T

L

185 RT 604797 95 n 12 3 .4 E -0 2 1 0 A 0136 RT 604798 13 95 n

L. 13 2 .2 E -0 3 1 0 0 • TL

187 RT 604799 13 95 L 14 l.O E -0 4 1 0 0 0188 RT 604300 13 95 2 15 6 .6 E -0 6 I 0 0 2189 RT 604808 13 95 3 3 3 .9 E -0 4 1 0 1 0190 RT 604809 13 95 ■ J 9 l . l E - 0 5 1 1 1191 RT 604810 13 95 3 10 2 .5 E -0 5 1 I 2192 RT 6 04 81 2 13 95 3 12 4 .5 E -0 5 1 1 0193 RT 604813 13 95 3 13 2 .8 E -0 6 1 1 2194 RT 6 05 07 3 13 96 2 8 5 .2 E -0 4 1 70 0 0195 RT 605079 13 96 L 9 1 .4 E -0 5 1 3 0 1196 RT 6 05080 13 96 2 10- 3 .3 E -0 5 L 3 0 2

A.7

--SYSTEM STATE BRANCHES- -CATESORIES-EC INIT SE St SPC FHS ECC PPC EFREQ SPC FHS ECC PPC

197 RT 605082 13 96 2 12 5 .B E -0 5 1 3 0 0198 RT 605083 13 96 2 13 3 .7 E -0 6 1 3 0 2199 RT 605363 13 97 2 a 3 .0 E -0 5 1 a 0 0200 RT 605365 13 97 2 10 1 .9 E -0 6 1 3 0 2201 RT 605367 13 97 n

L 12 3 .4 E -0 6 1 3 0 0202 RT 605648 13 98 2 a 1 .7 E -0 3 1 4 0 0203 RT 605649 13 98 L 9 4 .7 E -0 5 1 4 0 t1204 RT 605650 13 98 n 10 l . l E - 0 4 1 4 0 2205 RT 605651 13 96 i. 11 3 .0 E -0 6 1 4 0 n

L

206 RT 605652 13 98 12 1 .9 E -0 4 4 0 0207 RT 605653 13 98 2 13 1 .2 E -0 5 1 4 0 2208 RT 605663 13 98 7w a 2 .2 E -0 6 I 4 1 0209 RT 605933 13 99 2 8 4 .3 E -0 4 I 4 0 0210 RT 605934 13 99 9 1 .2 E -0 5 \i 4 0 1211 RT 605935 13 99 7

i . 10 2 .7 E -0 5 I 4 0 n

212 RT 605937 13 99 7 12 4 .8 E -0 5 4 0 0213 RT 605938 13 99 n

L 13 3 .1 E -0 6 [ 4 0 jL

214 RT 606213 13 100 2 3 9 .0 E -0 3 I 1 0 0215 RT 606219 13 100 n

L 9 2 .5 E -0 4 1 [ 0 1216 RT 606220 f 7

L -J 100 nL 10 5 .7 E -0 4 1 1 A T

RT 606221 13 100 r\ 11 1 .6 E -0 5 1i 1 0218 RT 606222 13 100 n 12 l.O E -0 3 i 1 0 0219 RT 606223 13 100 n

L 13 6 .5 E -0 5 1 I 0 L

220 RT 606224 13 100 2 14 3 . lE -0 6 4 1 0 0221 RT 606233 13 100 •J a 1 .2 E -0 5 <L 1 1 02 22 RT 606237 13 100 7 12 1 .3 E -0 6 I 1 1 0223 RT 606503 13 101 8 1 .5 E -0 5 1 3 0 0224 RT 606507 13 101 •*> 12 1 .7 E -0 6 i

L•y•J 0 0

225 RT 607073 13 103 2 8 5 .1 E -0 5 1 4 AV 0226 RT 607074 13 103 2 9 1 .4 E -0 6 1 4 0 1

RT 607075 13 103 2 10 3 .2 E -0 6 1 4 0 L

223 RT 607077 13 103 L 12 5 .7 E -0 6 1i 4 0 0229 RT 607358 13 104 n

L 8 1 .3 E -0 5 1 4 0 0230 RT 607362 13 104 2 12 1 .4 E -0 6 I 4 0 0231 RT 607643 13 105 2 8 4 .0 E -0 5 L 0 0232 RT 607644 13 105 n 9 U lE - 0 6 i

i•T 0 1

233 RT 607645 13 105 10 2 .5 E -0 6 \ 2 0 9

RT 607647 13 105 n 12 4 .5 E -0 6 \i 2 0 0235 RT 609068 13 110 n 3 9 .0 E -0 4 1 1 0 0236 RT 609069 13 110 2 9 2 .5 E -0 5 1 1 0 1237 RT 609070 13 110 n

L 10 5 .7 E -0 5 1 1 0 2238 RT 609071 13 110 2 11 1 .6 E -0 6 1 t 0 9

239 RT 6 09072 13 110 n 12 l .O E -0 4 1 1 0 0240 RT 609073 13 l i e n

L 13 6 .5 E -0 6 1 I 0 2241 RT 609083 13 110 3 8 1 .2 E -0 6 1 1 1 0242 RT 609353 13 111 3 1 .5 E -0 6 1 3 0 0243 RT 609923 13 113 n

L 8 5 .1 E -0 6 1 4 0 0244 RT 610208 13 114 n

L 3 1 .3 E -0 6 i 4 0 0245 RT 611918 13 120 2 a 9 .0 E -0 3 iL 0 0 0

A.8

--SYSTEH STATE BRANCHE3-- -CATESQRIES-:c IN IT s e a * SPC FNS ECC PPC EFRES SPC FNS ECC PPC

2 4 i RT 611919 13 120 2 9 2 .5 E - 0 4 1 0 0 1247 RT 611920 13 120 L 10 5 .7 E -0 4 1 0 0 n

L

248 RT 611921 13 120 2 11 1 .6 E -0 5 (I 0 0 n

L

249 RT 6 11922 13 120 L 12 l .O E -0 3 I 0 0 0

250 RT 611923 13 120 2 13 6 .5 E -0 5 1 0 0 2251 RT 611924 13 120 TL. 14 3 .1 E -C 6 4

i 0 0 02 52 RT 611933 13 120 7 a 1 .2 E -0 5 1 0 1 0253 RT 611937 13 120 3 12 1 .3 E -0 6 1 0 0254 RT 612203 13 121 n 8 U 5 E -0 5 1 3 0 0255 RT 6122Q7 13 121 7 12 U 7 E -0 6 1 • J

A•J 0256 RT 612773 13 123 n

L 8 5 .1 E -0 5 1 4 0 0257 RT 612774 13 123 9 1 .4 E -0 6 1 4 0 1258 RT 612775 13 123 £ 10 3 .2 E -0 6 1 4 0 2259 RT 612777 13 123 L 12 5 .8 E -0 6 1 4 0 0260 RT {>lo058 13 124 1 a 1 .3 E -0 5 1 4 A

y 0261 RT 613062 13 124 1 12 1 .4 E -0 6 4

i 4 ') 0262 RT 652958 14 95 L 3 6 .6 E -0 2 0 0 0263 RT 652959 14 95 n 9 1 .3 E -0 3 0 0

1L

264 RT 652960 14 95 n 10 4 .2 E -0 3 0 0 0 *7

265 RT 652961 14 95 2 11 1 .2 E -0 4 • i i j 0nL

266 RT 652962 14 95 2 12 7 .5 E -0 3 • j 0 V 0

267 RT 652963 14 95 7 13 4 .3 E -0 4 3 0 Q •7L,

268 RT 652964 14 95 2 14 2 .3 E -0 5 • J 0 0 0269 RT 652965 14 95 L 15 1 .4 E -0 6 0 0 7

270 RT 652973 14 95 3 3 8 .6 E - 0 5 •J 0 1 0271 RT 652974 14 95 T 9 2 .4 E -0 6 ■'j 0 L

<

272 RT 652975 14 95 T• J 10 5 .5 E -0 6 3 0 1

i i

273 RT 652977 14 95 3 12 9 .S E -0 6 • J 0 1 V

274 RT 653243 14 96 2 a l . l E - 0 4 T AV 0

275 RT 653244 14 96 0 9 3 . lE -0 6 • JA 1

276 RT 653245 14 96 n 10 7 .2 E -0 6 ■J •jt ( j i

277 RT 653247 14 96 0 12 1 .3 E -0 5 ■j i ) A

278 RT 653523 14 97 2 a 6 .7 E -0 6 T 70 0

279 RT 653813 14 93 L 8 3 .8 E -0 4 »0 0

280 RT 653814 14 98 ' ) 9 l .O E -0 5 i 0 12 8 1 RT i r T " i s

i - J 14 98 n 10 2 .4 E -0 5 3 4 0 L

282 RT 653317 14 98 / 12 4 .3 E -0 5 T 4 0 0

283 RT 653818 14 93 / 13 2 .7 E -0 6 3 4 0 2284 RT 654098 14 99 3 9 .4 E -0 5 3 4 0 0285 RT 654099 14 99 • n

L 9 2 -6 E -0 6 J 4 0 I

286 RT 654100 14 99 n 10 6 .0 E -0 6 3 4 0 2237 RT 654102 14 99 i 12 l . l E - 0 5 3 4 0 0

288 RT 654383 14 to o £ 3 2 .0 E -0 3 7 1 0 0289 RT 654384 14 100 2 9 5 .4 E -0 5 3 1 ( 1 I

290 RT 654385 14 100 2 10 1 .3 E -0 4 7W 1 0 2

291 RT 654386 14 100 L 11 3 .5 E -0 6 J 1 0 7u

2 92 RT 654387 14 100 n 12 2 .2 E -0 4 7•i 1 0 0

293 RT 654388 14 100 13 1 .4 E -0 5 7• J 1 0 7

2 9 4 RT 6 5 4 3 9 8 14 100 3 a 2 .6 E -0 6 3 1 1 0

A.9

-SYSTEM SlftTE BRANCHES- -CATEGORIES-;c IK IT SE 8I SPC FMS ECC PPC EFRES SPC FHS ECC PPC

295 RT 454448 14 101 2 8 3 .4 E -0 4 3 3 0 0m RT 455238 14 103 2 3 l . l E - 0 5 3 4 0 02 9 7 RT 435242 14 103 2 12 1 .3 E -0 4 3 4 0 0298 RT 455523 14 104 n

L 3 2 .8 E -0 4 T 4 0 0299 RT 453808 14 105 1 8 8 .7 E -0 4 3 2 0 0300 RT 457233 14 110 2 8 2 .0 E -0 4 T

•J 1 0 0301 RT 457234 14 110 2 9 5 .4 E -0 4 3 I 0 1302 RT 457235 14 110 2 10 1 .3 E -0 5 •J 1 0 23 03 RT 457237 14 110 2 12 2 .2 E -0 5 7

•J 1 0 0304 RT 457238 14 110 Z 13 1 .4 E -0 4 ■J

»i 0 2305 RT 458038 14 113 2 8 l . l E - 0 4 3 4 0 0304 RT 440083 14 120 2 8 2 .0 E -0 3 7

0 0 0307 RT 440084 14 120 n-

L 9 5 .4 E -0 5 3 0 0 (i

308 RT 440085 14 120 2 10 1 .3 E -0 4 3 0 0309 RT 440084 14 120 2 11 3 .5 E -0 4 C l 0 0310 RT 440087 14 120 • ■ J 12 2 .2 E -0 4 ‘j 0 0311 RT 440088 14 120 L 13 1 .4 E -0 5 ■J 0 0 2312 RT 440093 14 120 3 e 2 .6 E -0 4 7

•J 0 I 0313 RT 640348 14 121 L 3 3 .4 E -0 4 •'j

7 0 0314 RT 440938 14 123 1 3 1 .1E -C 5 7 4 0 0315 RT 440942 14 123 2 12 1 .3 E -0 6 J 4 0 n

314 RT 441223 14 124 0L, 3 2 .8 E -0 6 7 4 0 0

317 RT 701123 15 95 f\L, 8 2 .7 E -0 4 4 0 0 0

318 RT 701124 15 95 1 9 7 .5 E -0 6 4 0 0 1319 RT 701125 15 95 2 10 1 .7 E -0 5 4 0 i ) 2320 RT 701127 15 95 2 12 3 .1 E -0 5 4 0 0 0321 RT 701128 15 95 2 13 2 .0 E -0 6 4 0 0 £

3 22 RT 701973 15 98 nL 3 1 .5 E -0 6 4 4

'J 0323 RT 702548 15 100 i. 8 8 .1 E -0 4 4 [ 0 0

324 RT 708243 15 120 nL 3 8 .1 E -0 6 4 0 0 0

325 RT 749288 14 95 nL 8 6 .0 E -0 5 3 0 A A

324 RT 749289 16 95 u 9 1 .6 E -0 4 j 0 0 i

327 RT 749290 14 95 2 10 3 .8 E -0 4 3 0 0 i.

328 RT 749292 14 95 12 4 .8 E -0 6 ;j 0 0329 RT 750713 16 ^ ICO ? 8 1 .8 E -0 4 7 1 u 0330 RT 754413 16 120 Z 8 1 .3 E -0 6 0 0

331 RT 797453 i * T1 / 95 nL 8 2 .7 E -0 5 1 0 0 0

RT 797455 17 95 2 10 1 .7 E -0 6 1 0 0333 RT 797457 17 95 n

L 12 3 .1 E -0 4 1 0 0 0334 RT 845418 18 95 n

L 8 4 .0 E -0 4 3 0 0 03 35 RT 1134408 24 95 2 8 3 .2 E -0 4 1 0 0 0334 RT 1134409 24 95 z 9 3 .7 E -0 4 1 0 ■ } 1337 RT 1134410 24 95 L 10 2 .0 E -0 5 1 0 0 n

L

338 RT 1134412 24 95 2 12 3 .4 E -0 5 1 0 0 0339 RT 1134413 24 95 2 13 2 .3 E - 0 4 1 0 0 2340 RT 1135443 24 98 n

L a 1 .8 E -0 4 1 4 0 0341 RT 1134033 24 100 2 8 9 .4 E -0 4 1 1 0 03 4 2 RT 1134037 2 4 to o 2 12 l . l E - 0 4 1 1 0 03 43 RT 1141733 24 120 2 8 9 .4 E -0 4 1 0 0 0

A.IO

-SYSTEH STATE 8RAHCHES- -CATESQRIE3-:c INIT SEQ4 SPC FNS ECC PPC EFREa SPC FNS ECC PPC

344- RT 1141737 24 120 n{. 12 U lE -0 6 1 0 0 0

345 RT 1182773 25 95 L 8 3 .6 E -0 3 TL 0 0 0346 RT 1182774 25 95 •T

L 9 9 .8 E -0 5 nL 0 0 1L

347 RT 1182775 25 95 •TL 10 2 .3 E -0 4 1 0 0 0

L

348 RT 1182776 25 95 n U 6 .2 E -0 6 2 0 u nL

349 RT 1182777 25 95 nL 12 4 .0 E -0 4 TI, 0 0 0

350 RT 1182773 25 95 rSL 13 2 .6E -05 i. 0 0 2

351 RT 1182779 25 95 L 14 1 .2E -06 nL 0 0 0

352 RT 1132783 25 95 8 4 .6 E -0 6 L 0 I 0353 RT 1183058 25 96 L 8 6 . 1E“ 06 L 0 0354 RT 1183628 25 98 n

L 3 2 .0E -05 nL 4 0 0

355 RT 1183630 25 98 2 10 1 .3E -06 1 4 0 2356 RT 1183632 25 93 1 12 2 .3E -06 4 Ai 0357 RT 1183913 25 99 L 8 5 .0 E -0 6 n

L 4 0 0358 RT 1184198 25 too n

L 3 l .L E -0 4 Tu 1 0 0359 RT 1184199 25 100 0 9 2 .9 E -0 6 2 1 0 [

360 RT 1184200 25 100 ni. 10 6 .7 E -0 6 2 1i 0 • T

I.

361 RT 1184202 n e1-J 100 L 12 1 .2E -05 n

I 1 0 0362 RT 1187043 25 110 n

L a l . lE - 0 5 7 1 0 0363 RT 1187052 25 l i e n

L 12 1 .2E -06 7 1 0 0364 RT 1189898 25 120 • 7 a l . lE - 0 4 0 0 0365 RT 1139899 n c 120 9 2 .9E-C 6 0

& 0 I j 1366 RT 1189900 L-J 120 • T

L 10 6 .3 E -0 6 2 0 0 7

367 RT 1189902 120 2 12 1 .2E -05 nL 0 0 0

363 RT 1230938 26 95 0L. 8 2 .7E -04 4 0 0 0369 RT 1230939 26 95 n

L 9 7 .5E -06 4 0 0 1370 RT 1230940 26 95 n

L 10 1 .7E -05 4 0 0 n

371 RT 1230942 26 95 L 12 3 .1 E -0 5 4 0 n 0372 RT 1230943 26 95 2 13 2 .0 E -0 6 4 0 0 2V I • j RT 1231793 26 98 3 1 .5E -06 4 4 0 0374 RT 1232363 26 100 2 3 3 .1 E -0 6 4 i 0 0375 RT 1238063 26 120 / 3 3 . 1E“ 06 4 V 0 A

V

376 RT 1279103 27 95 a 3 .9 E -0 4 r• J 0 0 0

377 RT 1279104 27 95 9 l . lE - 0 5 5 0 0 1378 RT 1279105 27 95 7 10 2 .5E -05 J 0 0 7

379 RT 1279107 27 95 L 12 4 .5E -05 c■ J 0 I ' l 0

380 RT 1279108 0 7 95 nu 13 2 .9E -06 5 0 0 n

38! RT 1279958 • ■ V Tt ! 98 L 3 2 .2E -06 r. 4 0 0

332 RT 1280523 27 100 2 8 1 .2E -05 5 1 0 0383 RT 1280532 27 100 n

L 12 1 .3E -06 5 1 0 0384 RT 1283378 27 110 L a 1 .2E -06 5 1 0 0385 RT 1286228 27 120 2 8 1 .2E -05 5 0 0 0386 RT 1286232 27 120 2 12 1 .3E-06 5 0 0 0387 RT 1327268 28 95 n

L 3 3 .0 E -0 5 4 0 0 0388 RT 1327270 28 95 1 10 1 .9E -06 4 0 0 2389 RT 1327272 28 95 1 12 3 .4 E -0 6 4 0 0 0390 RT 1712588 36 95 2 8 3 .6 E -0 6 2 0 0 0391 RT 1760753 37 95 2 a 2 .7E -04 i 0 0 0392 RT 1760754 37 95 2 9 7 .5 E -0 6 1 0 0 1

A . l l

•C IHIT SEQt-SYSTEM STATE BRANCHES

SPC FWS ECC PPC EFREQ SPC-CATEBQRIES

FWS ECC PPC

491 EilFH 7 7 8 2 8 nL. 105 L 8 2 .1 E -0 5 1 n

L 0 0492 ENF« 77830 1 105 2 10 1 .3 E -0 6 I

0i. 0 2495 EHFH 778 32 1 105 2 12 2 .4 E -0 6 1 fy

L 0 0494 EHFW 79253 2 110 2 3 5 .3 E -0 4 1 1 0 0495 EMFM 7 9254 2 110 2 9 U 5 E -0 5 1 1 0 1496 EMFW 7 92 55 2 110 2 10 3 .4 E -0 5 1 1 0 2

497 EHFH 7 92 57 2 110 nL 12 6 .1 E -0 5 1 t 0 0

498 EflF« 79258 z 110 L 13 3 .9 E -0 6 1 1 0 nL

499 EHF« 80108 2 113 2 8 3 .0 E -0 6 - 1 4 0 0

500 EI1FH 124563 7 100 n a 5 .6 E -0 5 2 i 0 0501 EHFW 124569 3 100 L 9 1 .6 E -0 6 2 1 0 1502 EMFW 124570 7

J 100 U 10 3 .6 E -0 6 nL 1 0 2

503 EMFW 124572 100 2 12 6 .4 E - 0 6 nL 1 0 0

504 EMFW 127418 C p 110 2 8 6 .3 E -0 6 7 1i 0 0

505 EMFW 172733 4 100 i. 8 4 .3 E -0 6 1 i 0 0506 EMFW 199501 C

- J 23 1 1 6 .8 E -0 6 0 1 0 0507 EMFW 536656 12 •nc.:j 1 1 7 .0 E -0 5 0 i 0 0508 EMFW 538366 12 31 1 1 7 .8 E -0 6 1 0 0509 EMFW 606218 13 100 0L. 8 4 .0 E -0 3 1 L 0 0510 EMFW 606219 13 100 2 9 1 .3 E -0 4 1 i 0 1511 EMFW 606220 13 100 2 10 3 .1 E -0 4 1 0 n

512 EMFW 606221 13 100 2 11 8 .5 E -0 6 I 1 0 L

513 EMFW 606222 13 100 L 12 5 .4 E -0 4 1 1 0 0514 EMFW 606223 13 100 13 3 .5 E -0 5 1 1 0 n

L

515 EMFW 606224 13 100 14 1 .6 E -0 6 1 1 0 0516 EMFW 606233 13 100 8 6 .3 E -0 6 1 1 1 0517 EMFW 606503 13 101 2 8 8 .2 E -0 6 I 3 0 0518 EMFW 607073 13 103 3 2 .7 E -0 5 I 4 0 0519 EMFW 607075 13 103 2 10 1 .7 E -0 6 1 4 0 L

520 EMFW 607077 13 103 2 12 3 .1 E -0 6 1 4 0 0521 EMFW 607358 13 104 8 6 .8 E -0 6 1 4 0 0522 EMFW 607643 13 105 2 a 2 .1 E -0 5 a 0523 EMFW 607645 13 105 2 10 1 .4 E -0 6 1 2 0 i

524 EMFW 607647 13 105 n 12 2 .4 E -0 6 1 2 0 0525 EMFW 609068 13 110 2 3 5 .4 E -0 4 1 1 0 0526 EMFW 609069 13 110 9 1 .5 E -0 5 1 1 0 J

k

527 EMFW 609070 13 110 ni . 10 3 .4 E -0 5 1 1 0 n

L

523 EMFW 609072 13 110 nL 12 6 . lE -0 5 1 1 0 0

529 EMFW 609073 13 110 nL 13 3 .9 E -0 6 1 1 0 7im.

530 EMFW 609923 13 113 1 3 3 .0 E -0 6 1 4 0 0531 EMFW 6 54383 14 100 2 8 l . l E - 0 3 0 1 0 0532 EMFW 654384 14 100 n

L 9 2 .9 E -0 5 3 1 0 1533 EMFW 654385 14 too 2 10 6 .7 E -0 5 • J 1 0 2

534 EMFW 654386 14 100 2 11 1 .9 E -0 6 7• J I 0 2

535 EMFW 654387 14 100 nL 1 2 1 .2 E -0 4 3 1 0 0

536 EMFW 654388 14 100 0L. 13 7 .6 E -0 6 3 1 0 2537 EMFW 654398 14 100 3 8 1 .4 E -0 6 3 1 1 0538 EMFW 654668 14 101 n

L 8 1 .8 E -0 6 7- J 3 0 0

539 EMFW 6 55 23 8 14 103 1 8 6 . 0 8 - 0 6 3 4 0 0

A.12

-SYSTEK STATE SftANCHES- -CATESQRIES-—.c INIT SE St SPC FWS ECC PPC EFREQ SPC FWS ECC PPC

442 RT 6914413 144 95 2 13 3 .2 E -0 6 6 0 0 2443 RT 6915263 144 98 2 8 2 .5 E -0 6 6 4 0 0444 RT 6 91 58 33 144 100 2 8 1 .3 E -0 5 6 I 0 0445 RT 6 915837 144 100 2 12 1 .5 E -0 6 6 1 0 0446 RT 691 86 83 144 110 2 8 1 .3 E "0 6 6 1 0 0447 RT 6 921533 144 120 n

L 8 1 .3 E -0 5 6 0 0448 RT 6 921537 144 120 2 12 1 .5 E -0 6 a 0 0449 ENFN 6841 1 25 1 1 7 .6 E -0 2 1 0 0450 ENFW 7148 1 26 n 3 l . l E - 0 4 0 • j 0 0451 EHFjf 714? 1 26 n

L 9 2 .9 E -0 6 0 • J 0 I4 52 EHFH 7150 1 26 n

L 10 6 .8 E -0 6 0 V 0 2453 ERFN 7152 1 26 2 12 1 .2 E -0 5 0 7

• J 0 0

454 ERFW 7433 1 27 n 3 6 .3 E -0 6 0 0 0455 EHF« 7703 1i 28 1 8 3 .5 E - 0 4 0 4 0 0456 EHFN 7704 1 28 1 9 9 .8 E -0 6 0 4 0 I457 E m 7705 1 28 1

X 10 2 .3 E -0 5 0 4 0nL

458 EHF« 7707 1 23 iX 12 4 .0 E -0 5 0 4 0 0

459 ENFK 7708 1i 28 1 13 2 .6 E -0 6 0 4 0

ni.

460 EKFN 7988 1 29 1 8 3 .9 E -0 5 0 4 0 0461 ERFN 7989 I 29 I 9 2 .4 E -0 6 0 4 0 I

462 E m 7990 ii 29 1 10 5 .7 E -0 6 0 4 0 2463 EMFW 7992 1 29 1 12 1 .0 E -0 5 4 0 0

464 E m 8288 1 30 nL 3 2 .8 E -0 4 z 0 0

465 EMFH 3289 i 30 •TL 9 7 .7 E -0 6 n

L 0 1466 ENFN 3290 1

i 30 2 10 1 .3 E -0 5 00L. 0 2

467 E m 3292 1 30 2 12 3 .2 E -0 3 0 2 0 0

468 EMFW 8293 1 30 2 13 2 .0 E -0 6 0 0i. 0 2469 EMFW 8551 1 31 1 1 S .4 E -0 3 0 [ 0 0470 EMFW 8853 1 T T L 8 1 .2 E -0 5 0 • j 0 0471 EMFW 3862 1 32 7 12 1 .3 E -0 6 0 j 0 0472 EMFs 9413 1 34 1 3 4 .0 E -0 5 0 4 0 0473 EMFW 9414 1 34 1 9 l . l E - 0 6 0 4 0 I474 EMFW 9415 1 34 1 10 2 .5 E -0 6 0 4 0 n

L

475 EMFW 9417 1 34 1 12 4 .5 E -0 6 0 4 0 0476 EMFW 9698 1 35 1 8 9 .9 E -0 6 0 4 0 A

V

477 EMFW 9702 1 35 1 12 l . l E - 0 6 0 4 0 0478 EMFW 76403 n

L LOO L 3 4 .3 E -0 3 1 I 0 0479 EMFW 76404 9 100 9 1 .3 E -0 4 1 1 0 \

480 EMFW 76405 L 100 10 3 .1 E -0 4 I 1 0 1

481 EMFW 76406 •■J 100 L 11 8 .4 E -0 6 1 I 0 1

482 EMFW 76407 nL 100 7 12 5 .4 E -0 4 1 1 0 0

483 EMFW 76408 •yL too 7 13 3 .5 E -0 5 I 1 0 1

L.

484 EMFW 76409 L 100 7 14 1 .6 E -0 6 I 1 0 0485 EMFW 76418 L 100 3 8 6 .2 E -0 6 1 1 I 0486 EMFW 76688 2 101 2 3 8 .2 E -0 6 I 0 0487 EMFW 77258 n

L 103 2 8 2 .7 E -0 5 1 4 0488 EMFW 77260 2 103 2 10 1 .7 E -0 6 L 4 0489 EMFW 7 7 2 6 2 2 103 2 12 3 .1 E -0 6 1 4 0490 EMFW 7 75 43 2 104 2 8 6 .8 E -0 6 t 4 0 0

A.13

"SYSTEtl STATE 8RANCHES- -CATESORIES-c INIT SEQt SPC FWS ECC PPC EFREQ SPC FWS ECC PPC

540 EHFW 655523 14 104 n 8 1 .5 E -0 6 3 4 0 0541 ENFN 655808 14 105 I. 3 4 .7 E -0 6 3 2 0 0542 ENFW 657233 14 110 1 8 1 .2 E -0 4 1 0 0543 EMFN 657234 14 110 i. 9 3 .2 E -0 6 3 1 0 1544 EMFW 657235 14 110 2 10 7 .5 E -0 6 3 1 0 ' I

L

5 45 EMFW 657237 14 110 TL 12 1 .3 E -0 5 3 1 0 0

546 EMFW 702548 15 100 2 a 4 .3 E -0 6 4 1 0 0547 EMFW 1136033 24 100 2 a 5 .0 E -0 6 I 1 0 0548 EMFW 1184198 25 100 L 8 5 .6 E -0 5 ■1 0 0549 EMFW 1184199 25 100 L 9 1 .6 E -0 6 2 1 0 1550 EMFW 1184200 25 100 n

L 10 3 .6 E -0 6 04. 1 0 2551 EMFW 1184202 4. J 100 L 12 6 .4 E -0 6 n

L I 0 0552 EMFW 1187048 25 110 2 3 6 .3 E -0 6 L I 0 0553 EMFW 1232363 26 100 n

L a 4 .3 E -0 6 4 1 0 0554 EMFW 1280528 27 100 2 3 6 .3 E -0 6 5 1 0 0555 EMFW 1762178 3 7 100 2 8 4 .3 E -0 6 I 1 0 0556 EMFW 2318761 49 25 1 I 6 .8 E -0 6 0 I 0 0557 EMFW 6364621 133 25 1 1 7 .0 E -0 5 0 1 0 0558 EMFW 6366331 133 31 1 1 7 .9 E -0 6 0 I 0 0559 EMFW 6434183 134 100 L 8 4 .5 E -0 6 1 I 0 0560 EMFW 6915833 144 100 9 8 7 .0 E -0 6 6 i 0 0561 L3LB 5786356 121 24 1( 1 8 .7 E -0 5 0 0 05 62 L3LB 5786641 121 25 1 I 2 .6 E -0 6 0 1 0 0563 L3L3 5790061 121 37 1 I 2 .6 E -0 6 0 0 0 1 )

564 LSLB 5854778 122 95 n 8 5 .5 E -0 6 I 0 0 0565 L3LB 6075346 127 24 1 I 3 .4 E -0 4 0 0 0566 LSLB 6075631 127 25 1 1 2 .5 E -0 5 0 0 0567 LSLB 6077341 127 31 1 1 2 .5 E -0 6 0 1 AKJ 0568 LSLB 6079051 127 37 1 1 2 .5 E -0 5 0 0 0 0569 S3L6 5786356 121 24 1 1 6 .7 E -0 3 0 0 0 0570 33LB 5786641 121 25 1 t 2 .6 E -0 4 0 0 0571 SSLB 5787503 121 28 1 3 U 2 E -0 6 0 0 0572 SSLB 5788351 121 31 1 1 2 .6 E -0 5 0 1 0 0573 SSLB 5790061 121 37 1 I 2 .6 E -0 4 0 0 0 0574 SSLB 5790923 121 40 1 8 L .2E -06 0 4 0 0575 SSLB 5834543 122 24 • J 8 5 .5 E -0 4 1 0 0576 SSLB 5834544 122 24 L 9 1 .5 E -0 5 1 0 0 1577 SSLB 5834545 122 24 n

L 10 3 .5 E -0 5 1 0 0 nL

578 SSLB 5834547 122 24 nL 12 6 .2 E -0 5 1 0 0

579 SSLB 5834548 122 24 L 13 4 .0 E -0 6 1 0 0 Ti.

580 SSLB 5834823 122 25 2 3 1 .6 E -0 5 1 1 0 0581 SSLB 5834830 122 25 n 10 l.O E -0 6 1 1 0 2582 SSLB 5834832 122 25 12 1 .8 E -0 6 1 1 0 0583 SSLB 5836538 122 31 2 8 1 .6 E -0 6 1 1 0 0584 SSLB 5838248 122 37 2 8 1 .6 E -0 5 1 0 0 0585 SSLB 5838250 122 37 2 10 l .O E -0 6 1 0 0 2586 SSLB 583 82 52 122 37 n

L 12 1 .8 E -0 6 1 0 0 0587 SSLB 5882708 123 24 1 3 6 .5 E -0 6 2 0 0 05 88 SSLB 6316171 132 24 1 I 8 .0 E -0 6 0 0 0 0

A . I A

REC INIT SE 9I-SYSTEN- STATE BRANCHES

SPC FMS ECC PPC EFRES SPC--CATEBQRIES

FMS ECC PPC

589 SSLB 6 364336 133 24 1 1 7 .5 E -0 6 0 0 0 0590 LQNFN 45323 I 160 1 3 4 .9 E -0 1 0 0 0 0591 LQNFN 45324 1 160 1 9 1 .3 E -0 2 0 0 0 1592 LONFN 4 53 25 1 160 1 10 3 .1 E - 0 2 0 0 0 2593 LQNFN 45326 1 160 1 11 8 .6 E -0 4 0 0 0 2594 LO«F« 45327 1 160 I 12 5 .5 E -0 2 0 0 0 0595 LONFH 45328 1 160 1 13 3 .5 E -0 3 0 0 0 Ti .596 LQMFW 45329 1 160 1 14 1 .7 E -0 4 0 0 0 0597 LOMFW 45330 1 160 1 15 l . l E - 0 5 0 0 0 2598 LQMFH 45608 1 161 1 3 1 .7 E -0 3 0 j 0 0599 LQHFN 45609 I 161 1 9 4 .6 E -0 5 0 3 0 »i

600 LQHFN 45610 1 161 1 10 l . l E - 0 4 0 T'J 0 2601 LQNFM 45611 I 161 1 11 2 .9 E -0 6 0 j 0 n

L

602 LQHFK 45612 1 161 I 12 U 9 E -0 4 0 3 0 0603 LQNFM 45613 1 161 1 13 1 .2 E -0 5 0 3 0 2604 LQNFM 4 58 93 i 162 1 3 1 .7 E -0 4 0 •i 0 0605 LQNFM 45894 1 162 1 9 4 .6 E -0 6 0 7•J 0 1

606 LQNFM 45895 4i 162 1 10 l . l E - 0 5 0 3 0 nL

607 LQNFM 45897 1 162 1 12 1 .9 E -0 5 0 ■j 0 0

608 LQNFM 45898 1 162 1 13 1 .2 E -0 6 0 3 0 2609 LQNFM 46178 1 163 1 8 2 .8 E -0 3 0 4 0 V

610 LQNFM 46179 1 l6 o 1 9 7 .6 E -0 5 0 4 0 1611 LQNFM 4 6 1 BO ii 163 1 10 1 .3 E -0 4 0 4 0 •7

612 LQNFM 46181 1 163 i1 11 4 .9 E -0 6 0 4 0 2613 LQNFM 46132 4I 163 4

i 12 3 . lE -0 4 0 4 0 0614 LQNFM 46183 4

I 163 1 13 2 .0 E -0 5 0 4 0 2615 LQNFM 46463 1 164 ii 8 6 .9 E -0 4 0 4 0 0616 LQNFM 46464 1 164 1I 9 1 .9 E -0 5 0 4 0 1617 LQNFM 46465 1 164 I 10 4 .4 E " 0 5 0 4 0 ■)L.

618 LQNFM 46466 i 164 I 11 1 .2 E -0 6 0 4 0 7i.619 LQNFM 46467 4 164 1 12 7 .8 E -0 5 0 4 0 0620 LQNFM 46468 1 164 i

4 13 5 .0 E -0 6 0 4 0 2

621 LQNFM 93503 •T 160 8 3 .7 E -0 2 1 0 0 0622 LQNFM 93504 2 160 9 l .O E -0 3 1 0 0 1623 LQNFM 93505 2 160 L 10 2 .4 E -0 3 1 0 0 2

624 LQNFM 93506 160 nL 11 6 .6 E -0 5 1 0 0 2

625 LQNFM 935C7 2 160 nL 12 4 .2 E -0 3 1 0 0 0

626 LQNFM 93508 2 160 9 13 2 .7 E -0 4 1 0 0627 LQNFM 93509 Hi 160 L 14 1 .3 E -0 5 I 0 0 0628 LQNFM 93518 2 160 3 3 4 .9 E -0 5 1 0 1 0629 LQNFM 93519 2 160 3 9 1 .3 E -0 6 1 0 1 1630 LQNFM 93520 2 160 7■■i 10 3 . lE -0 6 1 0 I 2631 LQNFM 9 35 22 n 160 3 12 5 .5 E -0 6 I 0 1 0632 LQNFM 93788 2 161 ') 3 1 .3 E -0 4 1 3 0 0633 LQNFM 93789 2 161 2 9 3 .5 E -0 6 1 3 0 1634 LQNFM 93790 2 161 2 10 8 .1 E -0 6 1 3 0 2635 LQNFM 9 3792 L 161 2 12 1 .4 E -0 5 1 3 0 0636 LQNFM 94073 1 162 2 8 1 .3 E -0 5 1 3 0 0637 LQNFM 9 40 77 2 162 2 12 1 .4 E -0 6 1 3 0 0

A. 15

-SYSTEM STATE BRANCHES- -CATESQRIES-c INIT SEQt SPC FMS ECC PPC EFREQ SPC FMS ECC PPC

&3S LQNFN 943 58 2 163 2 3 2 .1 E -0 4 k 4 0 0639 LONFN 94359 2 163 2 9 5 .3 E -0 6 I 4 0 I640 LQNFM 94360 2 163 2 10 1 .3 E -0 5 1 4 0 2641 LQNFM 943 62 2 163 2 12 2 .4 E -0 5 1 4 0 0642 LQNFM 943 63 2 163 2 13 1 .5 E -0 6 I 4 0 i.

643 LQNFM 94643 9 164 2 8 5 .3 E -0 5 4 0 0644 LQNFM 946 44 n

L 164 nL 9 1 .5 E -0 6 I 4 0 I

645 LQNFM 94645 n 164 2 10 3 .4 E -0 6 1 4 0 2

646 LQNFM 94647 n 164 ni. 12 6 .0 E -0 6 1 4 0 0

647 LQNFM 141668 T•J 160 ni. 8 4 .4 E -0 4 2 0 0 0

648 LQNFM 141669 T• j 160 2 9 1 .2 E -0 5 2 0 0 1

649 LQNFM 141670 7■J 160 n 10 2 .8 E -0 5 2 0 0 2650 LQNFM 141672 7 160 9 12 5 .C E -0 5 n 0 0 0

651 LQNFM 141673 3 160 z 13 3 .2 E -0 6 n 0 0 *5

652 LQNFM 141953 161 nL a 1 .5 E -0 6 nL 3 0 0

653 LQNFM 142523 7•J 163 n 8 2 .5 E -0 6 7i. 4 0 0654 LQNFM 139833 i 160 2 8 3 .4 E -0 5 ik 0 0 0655 LQNFM 189335 4 160 n

L 10 2 . lE -0 6 1 0 0 L

656 LQNFM 139837 4 160 1 12 3 .8 E -0 6 1 0 0 0657 LQNFM 237983 c 160 f

i 8 4 .4 E -0 5 0 0 0 0653 LQNFM 237984 w 160 1 9 1 .2 E -0 6 0 0 1I659 LQNFM 237935 c

J 160 1 10 2 .8 E -0 6 0 0 0 2660 LQNFM 237987 e

J 160 1 12 5 .0 E -0 6 0 0 0661 LQNFM 286163 6 160 9 8 3 .4 E -0 6 1 0 0 0662 LQNFM 575133 \k i L 160 1 3 4 .5 E -0 4 0 0 0 0663 LQNFM 575139 12 160 tk 9 1 .2 E -0 5 0 0 0 1664 LQNFM 575140 12 160 1 10 2 .9 E -0 5 0 0 2

665 LQNFM 575142 1 2 160 1 12 5 .1 E -0 5 0 0 0666 LQNFM 575143 12 160 1t 13 3 .3 E -0 6 0 0 0 2667 LOHFM 575423 *7 161 41 8 1 .5 E -0 6 T■J 0 0663 LQNFM 575993 12 163 1 3 2 .6 E -0 6 0 4 0 066? LQNFM 623318 13 160 n 8 3 .7 E -0 2 1 0 0 0670 LQNFM 623319 13 160 n

i. 9 l .O E -0 3 I 0 0 1671 LQNFM 623320 T 7l-j 160 n 10 2 .4 E -0 3 1 0 0 n£

672 LQNFM 623321 13 160 nL 11 6 .6 E -0 5 0 0

673 LQNFM 6 23322 13 160 12 4 .3 E -0 3 0 0 0674 LQNFM 623323 13 160 L 13 2 .7 E -0 4 1 0 0 2675 LOHFM 623324 13 160 n

L 14 1 .3 E -0 5 I 0 0 0676 LQNFM 623333 13 160 7 3 4 .9 E -0 5 1 0 1 0677 LQNFM 623334 13 160 7•J 9 1 .3 E -0 6 1 0 1 1678 LQNFM 623335 13 160 J 10 3 .1 E -0 6 1 0 1 2679 LQNFM 623337 13 160 7 12 5 .5 E -0 6 1 0 I 0680 LQNFM 6 23603 13 161 n

L 8 1 .3 E -0 4 1 • j 0 0681 LQNFM 623604 13 161 L 9 3 .5 E -0 6 1 3 0 1682 LQNFM 623605 13 161 2 10 8 .2 E -0 6 I 3 0 2683 LQNFM 623607 13 161 2 12 1 .4 E -0 5 1 3 0 0

684 LQNFM 623888 13 162 2 8 1 .3 E -0 5 1 j 0 0

685 LQNFM 623892 13 162 2 12 1 .4 E -0 6 I 3 0 0

68& LOHFM 6 2 4 1 7 3 13 163 2 8 2 . 1 E - 0 4 1 4 0 0

A. 16

-SYSTEM STATE BRANCHES- -CATE6QRIE5-:c INIT SEQt SPC FHS ECC PPC EFREQ SPC FHS ECC PPC

687 LOKFH 624174 13 163 2 9 5 .8 E -0 6 1 4 0 I688 LQMFH 624175 13 163 2 10 1 .4 E -0 5 1 4 0 2689 LQMFH 624177 13 163 O

L 12 2 .4 E -0 5 1 0 0690 LQMFH 624178 13 163 2 13 1 .5 E -0 6 1 4 0 2691 LQMFH 624458 13 164 n

L 8 5 .3 E -0 5 1 4 0 06 92 LQMFH 624459 13 164 2 9 1 .5 E -0 6 0 1693 LQMFH 624460 13 164 n 10 3 .4 E -0 6 1 4 0 2694 LQMFH 6 2 4 4 6 2 13 164 n 12 6 .0 E -0 6 I 0 0695 LQMFH 671483 14 160 2 8 8 .2 E -0 3 ■j 0 0696 LQMFH 671484 14 160 2 9 2 .3 E -0 4 0 0 0 1697 LQMFH 671485 14 160 2 10 5 .3 E -0 4 3 0 0 2698 LQMFH 671486 14 160 2 11 1 .4 E -0 5 3 0 0 2699 LQMFH 6 71487 14 160 12 9 .3 E -0 4 ■j 0 0 0700 LQMFH 671488 14 160 2 13 6 .0 E -0 5 0 0 TL.701 LQMFH 671489 14 160 2 14 2 .8 E -0 6 3 0 0 07 02 LQMFH 671498 14 160 3 8 l . l E - 0 5 3 0 1 0703 LQMFH 671502 14 160 12 1 .2 E -0 6 3 0 1 0704 LQMFH 671768 14 161 n

L 3 2 .8 E -0 5 70 3 0 0705 LQMFH 671770 14 161 n

L 10 1 .8 E -0 6 3 •j 0 2706 LQMFH 671772 14 161 12 3 .2 E -0 6 3 0 0707 LQMFH 672053 14 162 L 3 2 .8 E -0 6 3 3 0 0708 LQMFH 672333 14 163 L 8 4 .7 E -0 5 -J 4 0 0709 LQMFH 672339 14 163 n 9 1 .3 E -0 6 3 4 0 1710 LQMFH 6 72340 14 163 •T 10 3 .0 E -0 6 ■j 4 n

V 2711 LQMFH 672342 14 163 12 5 .3 E -0 6 3 4 0 07 12 LQMFH 672623 14 164 2 8 1 .2 E -0 5 3 4 0 0713 LQMFH 672627 14 164 n 12 1 .3 E -0 6 3 4 0 0714 LQMFH 719648 15 160 n

L 3 3 .4 E -0 5 4 0 0 0715 LQMFH 719650 15 160 n 10 2 .2 E -0 6 4 0 c 7

716 LQMFH 719652 15 160 nu 12 3 .8 E -0 6 4 0 0 0

717 LQMFH 767813 16 160 2 a 7 .4 E -0 6 ■J 0 0 0718 LQMFH 815973 17 160 3 3 .4 E -0 6 1 0 0 AV719 LQMFH 1153133 24 160 3 3 .9 E - 0 5 1 r

V 0 0720 LQMFH 1153134 24 160 2 9 l . l E - 0 6 1 0 0 i721 LQMFH 1153135 24 160 n

L 10 2 .5 E -0 6 1 0 0 nL

7 22 LQMFH 1153137 24 160 nL 12 4 .4 E -0 6 1 0 0 0

723 LQMFH 1201298 •ncL J 160 n 8 4 .4 E -0 4 i. 0 0 0

724 LQMFH 1201299 2 j 160 9 1 .2 E -0 5 2 0 0 1725 LQMFH 1201300 25 160 2 10 2 .8 E -0 5 9 0 c 2726 LQMFH 1201302 25 160 n

L 12 5 .0 E -0 5 2 0 c 0727 LQMFH 1201303 25 160 2 13 3 .2 E -0 6 2 0 0 2728 LQMFH 1201583 25 161 2 3 1 .5 E -0 6 i . 3 0 0729 LQMFH 1202153 25 163 2 8 2 .5 E -0 6 n

i . 4 0 0730 LQMFH 1249463 26 160 2 8 3 .4 E -0 5 4 0 0 0731 LQMFH 1249465 26 160 2 10 2 .1 E -0 6 4 0 0 n

L

7 32 LQMFH 1249467 26 160 2 12 3 .8 E -0 6 4 0 0 0733 LQMFH 1297628 27 160 n

L 8 4 .9 E -0 5 5 0 0 0734 LQMFH 1297629 27 160 2 9 1 .3 E -0 6 5 0 0 1735 LQMFH 1297630 2 7 160 2 10 3 .1 E -0 6 5 0 0 2

A.17

-SYSTEH STATE BRANCHES- -CATESQRIE5-.c IN IT SEB4 SPC FMS ECC PPC EFRE8 SPC FMS ECC PPC

736 LQHFN 1 297632 2 7 160 2 1 2 5 .5 E -0 6 5 0 0 0737 LQHFH 1345793 28 160 2 8 3 .7 E - 0 6 4 0 0 0

738 LQHFN 1779278 37 160 2 8 3 .4 E - 0 5 1 0 0 0

739 LOHFM 1779280 37 160 2 10 2 .2 E -0 6 1 0 0 2740 LOHFM 1779282 3 7 160 2 12 3 .8 E -0 6 1 0 0 0

741 LOHFM 1827443 38 160 2 8 7 .4 E -0 6 3 0 0 0

742 LOHFM 1875608 39 160 2 3 3 .8 E -0 6 4 0 0 0

743 LOHFM 2357243 49 160 1 8 4 .4 E -0 5 0 0 0 0

744 LOHFM 2357244 49 160 1 9 1 .2 E -0 6 0 0 0 1745 LOHFM 2357245 49 160 1 10 2 .8 E -0 6 A'1 0 0 2746 LOHFM 2357247 49 160 I 12 5 .0 E -0 6 0 0 0 0

747 LOHFM 2405423 50 160 2 3 3 .4 E -0 6 1 0 0 0

748 LOHFM 2549903 53 160 1 a 4 .9 E -0 6 0 0 0 0

749 LOHFM 2935238 61 160 nL 8 3 .4 E -0 6 1 0 0 0

750 LOHFM 6403103 133 160 1 8 4 .6 E -0 4 0 0 0 0

751 LOHFM 6403104 133 160 1 9 1 .3 E -0 5 0 0 0 1752 LOHFM 6403105 133 160 ) 10 2 .9 E -0 5 0 0 0 2

753 LOHFM 6403107 133 160 1 12 5 .2 E -0 5 0 0 0 0

754 LOHFM 6403108 133 160 1 13 3 i3 E * 0 6 0 0 0 2

755 LOHFM 6403388 133 161 1 8 1 .6 E -0 6 0 •i 0 0

756 LOHFM 6403958 133 163 1 0 2 .6 E -0 6 0 4 0 0

757 LOHFM 6451283 134 160 nL a 3 .5 E -0 5 1 0 0 0

758 LOHFM 6451285 134 160 2 10 2 .2 E -0 6 1 0 0 2759 LOHFM 6451287 134 160 I, 12 3 .9 E -0 6 1 0 0 0

760 LOHFM 6932933 144 160 2 a 5 .4 E -0 5 6 0 0 0

761 LOHFM 6932934 144 160 nL 9 1 .5 E -0 6 6 0 0 1

762 LOHFM 6932935 144 160 1 10 3 .5 E -C 6 A 0 0nL

763 LOHFM 6932937 144 160 nL 12 6 .2 E -0 6 6 0 0 0

764 SSL! 6578 1 24 2 S 6 .6 E -0 2 0 0 0 0

765 SBLl 6579 1 24 L 9 1 .8 E -0 3 0 0 0 1766 SBLl 6580 24 2 10 4 .2 E -0 3 0 0 0 2767 SBLl 6531 I 24 2 11 1 .2 E -0 4 0 0 0 0

768 SBLl 6582 1 24 n 12 7 .5 E -0 3 0 0 0 0

769 SBLl 6583 1 24 2 13 4 .8 E -0 4 0 0 0 2770 SBLl 6584 1 24 14 2 .3 E -0 5 0 0 0 0

771 SBLl 6585 1 24 2 15 1 .4 E -0 6 0 0 0 2

772 SBLl 6593 1 24 V 8 3 .6 E -0 5 0 0 1 0

773 SBLl 6594 24 T‘J 9 2 .4 E -0 6 0 0 1 1774 SBLl 6595 1 24 3 10 5 .5 E -0 6 0 0 1 2

775 SBLl 6597 1 24 3 12 9 .8 E -0 6 0 0 1 0

776 SBLl 6863 1 25 2 3 1 .9 E -0 3 0 1 0 0

777 SBLl 6364 1 25 2 9 5 .4 E -0 5 0 I 0 1778 SBLl 6865 25 n

L 10 1 .2 E -0 4 0 \I 0 2779 SBLl 6866 1 25 n

L l l 3 .4 E -0 6 0 1 0 2780 SBLl 6867 1 25 2 12 2 ,2 E - 0 4 0 I 0 0781 SBLl 6868 1 25 2 13 U 4 E -0 5 0 1 0 2782 SBLl 6878 I 25 3 8 2 .5 E -0 6 0 1 I 0

783 SBLl 7148 1 26 2 a 3 .3 E -0 6 0 3 0 0

7 8 4 SBLL 7718 1 28 2 8 l . l E - 0 5 0 4 0 0

A.18

REC IN IT SEQ i--SYSTEH STATE BRANCHES

SPC FNS ECC PPC EFRES SPC--CATE60RIES

FNS ECC PPC

7 85 SBLl 7722 I 28 L 12 1 .2 E -0 6 0 4 0 0786 SBLl 8003 I 29 1 8 2 .8 E -0 6 0 4 0 0787 SBLl 3283 I 30 n

L 8 8 .7 E -0 6 0 2 0 0788 SBLl 8 573 I 31 1 8 2 .0 E - 0 4 0 1 0 0789 SBLl 8574 1 31 2 9 5 .4 E -0 6 0 I 0 1790 SBLl 8575 1 31 2 10 1 .2 E -0 5 0 I 0

791 SBLl 6577 1 31 12 2 .2 E - 0 5 0 1 0 0792 SBLl 8578 I 31 i, 13 1 .4 E -0 6 0 I 0 2793 SBLl 9428 1 34 8 l . l E - 0 6 0 4 0 0

794 SBLl 10283 1 37 3 2 .0 E -0 3 0 0 0 0

795 SBLl 10284 1 37 9 5 .4 E -0 5 0 0 0 I796 SBLl 10235 1 37 10 L 2 E - 0 4 0 0 0 L

797 SBLl 10286 1 37 2 11 3 .4 E - 0 6 0 0 0 1

798 SBLl 10287 1 37 2 12 2 .2 E -0 4 0 0 0 0799 SBLl 10288 1 3 7 n

L 13 1 .4 E -0 5 0 0 0 9

300 SBLl 10298 1 37 7•J 8 2 .5 E -0 6 0 0 1i 0

301 SBLl 10568 I 38 •T 8 3 .3 E -0 6 (\V 3 0 0

3 0 2 SBLl 11133 1 40 3 l . l E - 0 5 0 4 0 0803 SBLl 11142 I 40 2 12 1 .3 E -0 6 0 4 0 0804 SBLl 11423 1 41 a 2 .0 E -0 6 0 4 0 0

805 SBLl 74978 n 95 L 8 5 .0 E -0 3 I 0 0 0

806 SBLl 74979 95 7 9 1 .4 E -0 4 I 0 0 1807 SBLl 74980 95 2 10 3 .2 E - 0 4 1 0 0 9

i .

808 SBLl 74981 •*5 95 nL 11 3 .8 E -0 6 I 0 0 n

L

809 SBLl 74982 L 95 nL, 12 5 .7 E -0 4 K 0 0 0

810 SBLl 74983 n 95 • TL 13 3 .6 E -0 5 I 0 0 2

811 SBLl 74984 n 95 2 14 1 .7 E -0 6 I 0 0 0812 SBLl 74993 2 95 • J 8 6 .5 E -0 6 I 0 I 0

313 SBLl 75263 L 96 2 8 3 .5 E -0 6 I 3 0 0

814 SBLl 75833 98 0i. 8 2 .8 E -0 5 1 4 0 0815 SBLl 75335 2 98 n 10 1 .8 E -0 6 I 4 0

7

8 16 SBLl 75837 n 98 2 12 3 .2 E -0 6 iL 4 0 0

817 SBLl 76118 nL 99 i, 8 7 .1 E -0 6 4

i 4 0 0

313 SBLl 76403 • nL 1 0 0 n

L 8 1 .5 E -0 4 f I 0 0

819 SBLl 76404 2 100 2 9 4 .1 E -0 6 I I 0 I820 SBLl 76405 o

L 1 0 0 L 10 9 .5 E -0 6 I I 0

821 SBLl 76407 L 100 n/ 12 1 .7 E -0 5 I I 0 0

3 22 SBLl 76403 n 100 7 13 l . l E - 0 6 1 t 0 2823 SBLl 79253 n 1 10 n

L 3 1 .5 E -0 5 I I 0 0824 SBLl 79257 n

i. 110 2 12 1 .7 E -0 6 I 1 0 08 25 SBLl 82103 1 120 2 3 1 .5 E -0 4 I 0 0 0826 SBLl 82104 2 120 7 9 4 .1 E -0 6 I 0 0 1827 SBLl 82105 n 120 n

L. 10 9 .5 E -0 6 I 0 0 9u

828 SBLl 32107 nL 120 n

L 12 1 .7 E -0 5 I 0 0 08 29 SBLl 82108 2 120 2 13 l . l E - 0 6 I 0 0 28 30 SBLl 123143 T•J 95 2 8 5 .9 E -0 5 2 0 0 0831 SBLl 123144 3 95 2 9 1 .6 E -0 6 2 0 0 18 32 SBLl 123145 W 95 2 10 3 .8 E -0 6 2 0 0 2833 SBLl 123147 3 95 2 12 6 .7 E -0 6 2 0 0 0

A. 19

o-o

oo

*—

C'l <o C-J o

<3. —

H o

C--4

<*:? *0 o

—

• CM

.0

c*4 o

—

« c *i c-^

o

r^l c>

o

o

o

C2*

O'

o

I O

i a

c/9tx»Q£OU9 to

O

O*

<2* o

O

*0

'w* "O'

O’

'O

0» O

O

o

O

* -i—•

O

-S* •■"J?

0* O

' 'O

' o

0»

O

' o

0

»

'S*

O

O'

CS* O

' O

' O

' -O

O

' O

’ 'O

’ o

•—

O*

O’

o

o o*

C o

O’

•o

o

"O’

-O’

o

o

ro

*nf "'t*

t-9o

.C

O

rMrM

«-*'0''0.0'0’oh-7 ro h*7 I’O

■? r--?

Q<Ulce:

ac

L

J ■cc CJ oe LuG

O

*0

-0

0

'O-0<3

.•«0

inO’

■<1o

>-0O

’M

3O

’M

3O

’M

30

M0•«r0

O’

M3

•00

InO'

M3

•O-00

inO’

-00-0•0

M3

0-0

-a0*

1/3O

’M

3'O

030

-0O'

•M"

M3

0m•0

M3

t'3•0

in010

•OM

3O

’•O

’-0•01

-00-00

M?

0M

O0

inO'

M3

O'

-000

Jj

UJ

CO

C

Oill10

UJ

O’*

-0

tlir-“

lliO

'

M*

1U

JO

'

M3

ui

03

til0

3U

J0m

1U

JU

JCMM

UJ

cr-

03

tijr«»

tn

1U

l-oftM

»

tiltil-43

-0

til-00

3

UJ

00

r-4

UJ

03

lilCM^'3

UJ

r-^

UJ

mU

J

■It*

tilinO

'

UJ

r''U

lIjJ1/3

Ul

r—til0

3til

«sf

liiM

3

0“

UJ

1—iL

UJ

0t-3

lit

r--

til0

-U

lr-3

UJ

003

Ul

’"♦'U

JO

'mm«M

Ul

1-3M

3

til-0

lilt'3

mCM

liif

-*r-3

UJ

1-3

b3

CO

C

OC

OC

DC

OO

'O

' ■■ 4

cM0

3tm

03

a-

O'

CMM

■tf-C

O0

30

3O

’CM

CO

CO

O'

'Ot'T

03

CM0

3C

r-«

oCM

1-3C

OO

's

-CM

r-3C

OCXI

CO

03

CXI0

CMC

D

CM

cMCM

CMCM

CMCM

C'J

CMCM

CMc-»

CMCM

c-JCM

r-Jr-o

CMCM

CMCM

CMC

-4CM

CMCM

CMCM

CMCM

CMCM

CMC--4

C-4

04

CMCM

C-4CM

h3

CMCM

CMC

4CM

CMCM

OCN

<r COC

O

Ul.

lT5

««

i-«^

'rf-"«

r^in

»h

~-ln

toir?

iolrJ

io«

r?io

-oc

ac

pc

i:io-o

-0’

oO

'0'0

O

- CM

CM

CM

CM

C

-'l O

- t>~

O-

Cr-

0~

O

- cr-

Cr-

0~

O

' o

- O

- O

- -O

O

' O

-O

O

' ■’“

»■O’

o

O'

O' >0

UT tr»

m

IT9 10

in 10

-o

COCM

CM

CM

CM

CM

o

- 0

~

!>• O

* o

- O

- O

' O

- O

-

co

o

>- Ou C

O

CO

I

H?

|v^ tn

CM

C"j

CM

C-4

r-J C

M

1-0 K

» K

» ^

0

fo

t-Tt h*9

r-7 fO

*'">

K9

K9

K«

hO

h-'S h-"*

r-O

f-O

fO

f-O

CD

CO

CD

CD

■«rin

K.

03

CO

1-3in

Ml

I''0

3O

'0

3C

DC

D<31

C-4

h3

03

O'

r-4h

30

3CM

03

Cr-

C3

CMl'-3

CD

et"'S

’CM

tnt"3

r-3m

03

tntn

f-

M3

M3

0h*3

O'

O'

O'

O'

r"O

'O

'O

'0

-O

'O

'O

'O

'0

r*'.in

U3

1-3fM

CMCM

CMM

3f"-

CMC

-4CM

min

M3

-0•M

3•M

lr-—

•ifO

'C

DC

D00

inCM

h3

CMh

3b

3t'7

r*3•M

?<

or

-r—

r-

r-*.r-'

r-

CO

<0

M3

-oM

3cr-

CMCM

CMCM

CM0

0cr-

O"

O'

O'

O'

0-

O'

O'

O-'

O'

O'

CMC

D0

mto

to0

O'

M3

MCIM

3•-0

M3

0•Bt-

-If■If

inU

3in

U3

inM

3M

3-D

-D-0

0-

O'

f-4CM

CMCM

CMCM

CMt-3

1-0CM

f'3r

-O

'1-3

t-3h

3t-3

00

00

0<S’

00

0'w

'0

•S’

00

«C3•S

’•S

’0

0-S

’in

tnU

Tin

inin

inin

tntn

tntn

inm

inin

inin

tnM

3M

3-D

M3

M3

M3

M3

-0•D

m3

•M3

•DM

3M

3M

3-0

M3

M3

M3

M3

M3

M3

-43-43

-DM

3-43

M3

M3

•m3-0

-43-D

•Ml

•M3

•M3

<M3•D

—4, .

, tf

—4

,,

,<■ 4

^4

—4

, (

■ 4w

—4,

. ■ *•1 4

, .

p‘i 4..M

n-4■—

1—

4•.4

•«4-J

—J

-JU

l-J

u_J

—1-J

—J

..J«J

U-J

-J-J

—1

.Ju

_J—

J.-1

.J_

lU

—1

—I

«-Ju

u_J

-_JU

-Ju

IXi

CO

CD

COC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DC

DCO

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CD

CO

CD

03

CD

CD

CD

CD

CD

CD

CD

CD

paC

DC

DC

DC

Dto

totn

toC

Oto

toto

cnto

toto

tnto

toto

toto

toto

toto

toto

toto

C/3

toC

Oto

CO

toto

toto

03

toto

C/3

CO

CO

toto

CO

toto

toto

CO

oa^

u-9

m9

h’«

CXI O

'foi

Ml r-o

CMin

M3

r***.00

O'

0,

,CM

K*

inM

3h—

CD

O'

0CM

1-0•M*

inM

3I"

.00

O'

0CM

K>

•BhliO

•M3

h-

CD

O'

0CM

•tfU

'7in

Inin

Inm

inin

inin

-M»M

3-D

•M3

-0-0

M3

-O-O

-0r--

r-~f'.

1"

f"^'-.

r-

r-

r-'f"

CD

09

09

CD

03

CD

03

03

CD

09

CO

OE3o

a0

3C

D0

300

CD

CD

03

CD

CD

03

CD

CD

CD

00

CD

03

03

CO

133C

DC

OC

DC

DC

DC

Dco

03

CD

CD

CD

CD

-o>

o-o

•o-n

-o-o

-o-o

•>o

-o-4:4

>0

-0•n

-0-0

-0-0

-a

-0-0

-0-0

>40

-a

>0

>0

>0

>0

CO

cn

03

CO

00

CO

00

cu

CO

CO

00

CO

00

mC

Ocx

aC

Oc-

4r

oro

roro

hOro

ror-

Jro

ro»—

>O

'0

«o

00

00

00

•>0

>40

•>o

•>0

-JD

-n>4

0>0

-0C

OC

O00

CO

CO

CO

00

O>4

0C

O-o

!>-

cn

-f»>

c-4

rof—

o>•J

O00

•0cr

-c

n•4

k>t-

4ro

0-0

CO

•—4

0c

no»

-C

-4ro

»—0

-43

CO

-0o

>t/

iC

-lro

0•0

CO

-00

-t/

l-r

>

toto

toto

toto

toto

totn

tntn

tnto

UJ

tntn

cnt/

3U

Jcn

tncn

cnc/

acn

tner

aer

atn

tntn

tntn

tnto

tncn

tntn

tnto

totn

tncn

cncn

03

CO

03

oo

ea0

3C

OC

O0

30

30

3C

O0

30

30

30

3C

OC

OC

Oto

03

CO

CO

toC

OC

OC

O0

3C

OC

OC

O0

3C

O0

300

03C

O0

30

3D

30

3C

OC

OC

O03

CO

03

r-

r"

r~r*

r"r“

f—r-

r”

r~r*

f“r~

r~r~

r~r~

l“-

r"

r*"

r~*

r~r—

r~r*

r~r“

r-

r~r~

r~r"

r~r—

r*r~

r“

r~r~

r'

r“

r"r—

r“

Mr

oh

Jro

ro

roro

ror-J

roro

roro

roro

roro

hJro

roro

roro

h-j

rot—

r»►—

r->*—

r—e»

1—“

r->

►—>

r-*

r3

»>•*

Cr-

O'

O'

O'

O'

O'

O'

O'

r-J

*—1 -

r->

r->

•—>

I—>

*—>

o>n>

er'

o>

cr-

ca~cr

-Cr>

O'cn

-OC-4

c-4C-4

c-4c-4

t-4

c-4

•->-4

rj

ro»—

r»>

►—>

~ocr>

O'

O'

9Tc

nc

n0

00

0t-4

r>3

00

'>4

—-1

>»l

-J

'-J•■**

>►—

c-4

O'O'

o>

Cr>

O'O

'O'

"4c-

4CO

COCO

COCO

COC-4

0O'

0-

O'ro

ro>0

cr-

cn

cn

O'c-

4r-

J-0

O'c

nc

n•0

COCO

->j

Cr~

O'

O'r-

JCO

-»h.

CO0

>0

0-0

ror-

Jro

ro0

00

-0c-

4>0

>0

0ro

O'0

»jt-4

r-J

c-4

COr'

J-o

roc

nr-

J-0

00

cn

cn

o*

O't-4

C-4

c-4

c-4

-x4

>0

03

-'.4

•x4

•x4

->-i

0-

00

0<a-

•xj

*0

cn

O'-

—1

CO0

3t-

4-0

-Or-

Jc

n»4

c-4-o

O'to

cn

CO•x

4•0

c/t

o-

O'

O'

cn

cn

>0

cn

0c-

4-0

-0•'

J•x

40

roCO

000

30

-Cr>

O'­

•—>

r—r—

►—O

'0

-O

'0

-0

-O

'cr

-O

'►—

►->

O'

O'

»—>

O'

O'

CO0

3c-

4t-4

^J

0-4

3CO

oo

C>l

C4

cnCO

CO-4

tn■*

»C4

COc-4

-0cn

C-4

to m fO

c>i

t-4

cx4

r--:*

c-4

r-J

i-j

h-j

r-J

ro

r.j

*—■

C-4

C-4

C-4

C-4

C--4

C4

C-4

C-4

C-4

C-s

|C

-4C

-4

o

-o

*oO

-t

J -O

-o

o*

i»

•>

- t.r

iCH

c-

4 cH

r

j r-

j *o

-a

c-

4 m

r-

j ro

r-

J r*

Jo

-o

^ «

o CO

lui

<p

cn

cfl

-J c

n

c-4

^s>

ro

r

o

r-si

^•

J ^

o

ro

|v

j r

o

^

•^'o

cr-c

ncnc

ncnc

ncn-

r^cn

-o

-<

3-

or

oo

'-<

‘'4

:i~

o-

<3

>-

o-

^r

'Jr

or

oc

Tic

nt

Ji

c^

^c

ji

cr

ic

nc

nc

nc

n«

oo

o>

to

to

"O -

< ra

CO —H s

2 ^

«n

=2

ts3

ror-

jr-

jro

roro

r-J

ror>

Jr-

Jr>

jrs

>r-

Jr-

Jr>

jro

r-J

r-J

r>J

ror-

Jr-

Jr-

JI

JC

-4r-

Jro

r-J

r-J

hJ

r-J

roro

roro

r-J

r-j

r'j

ror-

Jr-

Jro

^J

ror-

Jro

^J

r-J

r-J

•“►—

»—•—

'—►—

►—►—

►—

1—k—

CO

CO

00

roro

0>0

00

CO

CO

03

CO

CO

CO

ro0

>0

03

CD

00

roC

O0

3

-x|

AO

ht—

'*—

c-4

»—O

'—4

1—>

c-4

►-->

O'

ror-

3,—

■r-

>ro

,—C

Ox

j~|a

>►

->•x

ic-

4•—

cr-

O'

•4*

0-

O'

c-4

•—c

nc

n-«

»t-

4ro

c-4

«•

m•

■•

«m

00

c-4

cza

CO

CO

•4^

0.C

k.»—

>0

30

30

3-o

•—>

c-4

■pm>/

4»<3

>•>

4•0

o>

c-4

—>J

roC

O0

>43

xj

^J

•0c

no

>c

n0

3C

O•'-4

CCl

cr>

>0

c-4

cn

-xl

C-4

Tm

mT

mm

mm 1

mm

mm

mrn

rnm

mm

mm

mm

mm

mm

Tm

mm

rnT

Tm

mrr

i01

T*m

Tm

Tm

*0

0O

'•0

<0

•00

*O

'O

'O

'•0

0-O

•0-C

3•0

0•z

>O

'•0

-o-

•s>

•c>

O'

O'

o>

•00

O'

0•0

1•0

•00

•0<0

00

•00

-o

-O

'c

nO

'c

nO

'o

>O

'O

'c

nO

'c

nO

'O

'O

'tj

nO

'o

>-4

»*c

nC>

-4cr

-O

'O

'O

'Cr

>O

'c

nO

'o

~O

'O

'O

'O

'O

'O

'tn

O'

Cr^

O'

O'tn

m 3

0 ac

m

tn

“tj

I “O

I

"

1 m "T1 so m fo

ro

t-

4

c-4

c-

4r

o

ro

rs

j r

o

foto "O o

c-4 O

-4«- Oi

hO

r--

O

o.

0> t

o O

O'

o o

o* •=

> o*

•£>0

<0<5

>0<0

><^0

0O

' o

>

o>

o

>

O'*

m cn I I I

C> 0

> lO

ojoo

>o>

ro»—

‘0>o

>0'0

>o»0

'0>o

*ro

o o

o o

> ro

o“O

-SYSTEH STATE BRANCHES- -CATEGQRIES-c INIT SEQt SPC FNS ECC PPC EFREQ SPC FNS ECC PPC

9 32 SBL2 6364351 133 24 2 1 7 .5 E -0 6 0 0 0 0933 S6TR 6571 1 24 2 1 8 .0 E -0 3 0 0 0 093* SGTR 6586 1 24 3 1 l.O E -0 5 0 0 1 0935 SGTR 6856 1 25 n

L 1 2 .4 E -0 4 0 1 0 0936 SGTR 7711 1 23 2 1 1 .3 E -0 6 0 4 0 0937 SGTR 8281 1 30 2 1 1 .0 E -0 6 0 2 0 0938 SGTR 8566 1 31 2 1 2 .4 E -0 5 0 I 0 0939 SGTR 10276 1 37 2 1 2 .4 E -0 4 0 0 0 0940 SGTR 11131 1 40 2 1 1 .3 E -0 6 0 4 0 0941 SGTR 74971 2 95 1 6 .1 E -0 4 1 0 0 09 42 SGTR 75256 •J 96 2 1 l.O E -0 6 I 0 0 0943 SGTR 75826 98 2 1 3 .4 E -0 6 1 4 0 0944 SGTR 76396 'I

L. 100 nL 1 1 .3 E -0 5 i 1 0 0

945 SGTR 79246 110 i 1 1 .3 E -0 6 I 4I 0 0

946 SGTR 82096 2 120 2 1 1 .8 E -0 5 1 0 0 0947 SGTR 123136 3 95 2 1 7 .1 E -0 6 L 0 0 0948 SGTR 536386 12 24 n

L I 7 .4 E -0 6 0 0 0 0949 SGTR 604786 13 95 2 1 6 .1 E -0 4 4

i 0 0 0950 SGTR 605071 13 96 n

L 1 l.O E -0 6 fL 3 0 0951 SGTR 605641 1 3 98 n

L 1 3 .4 E -0 6 1 4 0 0952 SGTR 606211 13 100 n

L I 1 .8 E -0 5 1 I 0 0953 SGTR 609061 13 110 •T

L 1 I t E E - 0 6 41 0 0

954 SGTR 611911 13 120 2 I 1 .8 E -0 5 1 0 0 0955 SGTR 652951 14 95 n 1 1 .3 E -0 4 0 0 0956 SGTR 654376 14 100 I 4 .0 E -0 6 3 1 0 0957 SGTR 660076 14 120 L 1 4 .0 E -0 6 3 0 0 0958 SGTR 1182766 25 95 n

L 1 7 .1 E -0 6 0 0 0 0959 SGTR 6364351 133 24 A

L 1 7 .5 E -0 6 0 0 0 0960 S I 6573 1 24 n 8 6 .6 E -0 3 0 0 0 0961 SI 6579 1 24 n

L 9 1 .8 E -0 4 0 0 0 1962 SI 6580 1 24 2 10 4 .2 E -0 4 0 0 0 L

963 SI 6581 1 24 11 1 .2 E -0 5 0 0 • n

964 SI 6582 1 24 1 12 7 .5 E -0 4 0 0 0965 31 6533 1 24 L 13 4 .8 E -0 5 0 0 0 n

L

966 S I 6584 1 24 14 2 .3 E -0 6 c 0 0 0967 S I 6363 1 25 2 8 2 .0 E -0 4 0 1 0 0968 SI 6364 1 25 o

L 9 5 .4 E -0 6 0 1 0 1969 SI 6365 4i 25 n 10 1 .2 E -0 5 0 1 0 n

L

970 SI 6867 1 25 L 12 2 .2 E -0 5 0 4I 0 0

971 SI 6868 1 25 13 1 .4 E -0 6 0 1 0 2972 S I 7718 1 28 n 8 l . l E - 0 6 0 4 0 0973 SI 8573 1 31 n 8 2 .0 E -0 5 0 1 0 0974 SI 8575 1 31 T 10 1 .2 E -0 6 0 I 0 2975 S I B577 1 31 2 12 2 .2 E -0 6 0 1 0 0976 SI 10283 1 37 2 8 2 .0 E -0 4 0 0 0 0977 S I 10284 1 37 O

L 9 5 .4 E -0 6 0 0 0 1978 S I 10285 I 37 2 10 1 .3 E -0 5 0 0 0 2979 S I 10287 1 37 2 12 2 .2 E -0 5 0 0 0 09 80 S I 10288 1 37 2 13 1 .4 E -0 6 0 0 0 2

A.22

--SYSTEtt STATE BRANCHES- -CATEBORIES-REC IN IT SEQ« SPC FNS ECC PPC EFREa SPC FNS ECC PPC

981 S I 11138 1 40 2 8 l . l E - 0 6 0 4 0 09 8 2 S I 74978 2 95 2 8 5 .0 E -0 4 1 0 0 09 8 J S I 74979 2 95 2 9 1 .4 E -0 5 1 0 0 1984 SI 74980 2 95 2 10 3 .2 E -0 5 I 0 0 2985 S I 7 49 82 I, 95 12 5 .7 E -0 5 I 0 0 0986 S I 74983 1 95 n

L 13 3 .6 E -0 6 I 0 2987 S I 75833 2 98 2 8 2 .8 E -0 6 1 4 0 0988 SI 76403 2 100 2 3 L 5 E - 0 5 1 1 0 0989 SI 76407 r\

L 100 L 12 1 .7 E -0 6 1 1 0 0990 S I 79253 2 110 1 8 1 .5 E -0 6 1 1 0 0991 31 82103 n 120 n

L 8 1 .5 E -0 5 I 0 0 0992 S I 82 1 0 7 2 120 n

L 12 1 .7 E -0 6 1 0 0 0993 S I 123143 3 95 n 8 5 .9 E -0 6 T

i. 0 0 0994 31 536393 12 24 2 8 6 .1 E -0 6 0 0 0 0995 S I 604793 13 95 2 8 5 .0 E -0 4 I 0 0 0996 S I 604794 13 95 n 9 1 .4 E -0 5 I 0 0 1997 S I 604795 13 95 10 3 .2 E -0 5 1 0 0 n

L

998 SI 604797 13 95 nL 12 5 .7 E -0 5 1 0 0 0

999 S I 604798 13 95 L 13 3 .7 E -0 6 1 0 0 n

1000 S I 605648 13 98 2 3 2 .9 E -0 6 I I 0 01001 SI 606213 13 100 L 8 1 .5 E -0 5 I 4

i 0 ()

1002 31 6 06222 13 100 L 12 1 .7 E -0 6 >i 1 0 0

1003 31 609068 13 n o 2 8 1 .5 E -0 6 1 1 0 Ay

1004 SI 611918 13 120 0 3 1 .5 E -0 5 si 0 0 0

1005 S I 6 11922 13 120 nL 12 1 .7 E -0 6 1 0 .■j 0

1006 S I 652958 14 95 2 3 l . l E - 0 4 3 0 0 01007 S I 652959 14 95 n

L 9 3 . lE -0 6 3 0 0 I1008 SI 652960 14 95 n

L 10 7 .1 E -0 6 3 0 01009 S I 652962 14 95 12 1 .3 E -0 5 3 'J 01010 S I 654383 14 100 2 8 3 .3 E -0 6 ■j 1 01011 S I 6 60083 14 120 7 8 3 .3 E -0 6 3 0 01012 S i 1182773 25 95 n

L 3 5 .9 E -0 6 0 01013 S I 6364358 133 24 •y

L 3 6 .2 E -0 6 0 0 0 0

A.23

A . 2 S e a u e a c o h v S v « t M i S t a t e C a t e g o r y

A.24

SYSTEM STATE CATEGORIESR E C T Y P E I N I T S P C F W S E C C P P C E F R E Q

1 N O R M R T 0 0 O (IJ 5 « o E " * " 0 0

2 F W . R T 0 1 0 0 1 . 6 E - 0 1

O F W R T C) y 0 1 4 . 9 E - 0 4

4 F W . R T 0 0 o 3 . O E - 0 5

5 ” F W R T 0 4 0 0 1 . 9 E - 0 3

<b F W R T 0 4 0 1 4 . 7 E - 0 5

7 F W R T 0 4 0o

1 . 3 E - 0 4

8 F W R T 0 0 0 5 . 8 E - 0 4

9 F W R T 0 0 1 1 . 4 E - 0 5

1 0 F W R T 0 0 2 3 . 7 E - 0 5

1 1 S L R T 1 0 0 0 6 . 9 E - 0 1

1 2 S L R T 1 0 (I) 1 1 . 7 E - 0 2

1 3 S L R T 1 0 0 y 4 . 5 E - 0 2

1 4 S L R T 1 0 1 0 9 4 0 E ~ 0 4

1 5 S L R T 1 0 1 1 2 * 2 E - 0 5

1 6 S L R T •1 0 1 2 5 . 6 E - 0 5

1 7 S S R T 1 0 1 2 . 3 E - 0 5

1 8 S S R T 1J. "T 0 7 u 7 E - 0 5

1 9 S S R T 1 4 0 Cs 5 « O E - 0 3

2 0 S S R T 1 4 0 1 1 4 2 E - 0 4

2 1 S S R T 4 0 'y3 - 2 E - 0 4

S S R T 1 4 1 0 4 . 4 E - 0 6O ' ? S L R T 1 1 (15 0 2 . 2 E - 0 2

2 4 S S R T 1 1 (Jf 1 5 . 4 E - 0 4

2 5 S S R T 1 1 0 1 4 4 E - 0 3

2 6 S S R T i. 1i. 1 0 2 4 S E - 0 5

2 7 S S R T4X O 0 0 S . B E - 0 5

2 8 S S R T 1 O 0 1•L 2 > 2 E - 0 6

2 9 S S R T 1 !Z (1) 5 . 0 E - - 0 6

3 0 S L R T o 0 0 0 a . 2 E - 0 3

3 1 S L R To 0 0 1 2 . O E - 0 4

S L R T jX 0 <1) '•y5 . 3 E - 0 4

S L R T o 0 1 0 9 . 2 E - - 0 6

3 4 S S R T o y 0 <1) 1 4 2 E - 0 5

3 5 S S R T 4 0 0 5 . 5 E - 0 5

3 6 S S R T 4 0 2 4 6 E " " 0 6^**T

/ S S R T 1 (l! (1) 2 4 6 E ” D 4

3 8 S S R T 1 0 1 5 . 8 E - 0 6

3 9 S S R T uZ 1 0 1 4 3 E - 0 5

4 0 S L R T y, (1) 0 / 4 6 E ~ 0 2

4 1 S L R T 0 1 1 4 9 E - 0 3

4 2 S L R T (1) 5 4 O E - 0 3

4 3 S L R T 1 0 9 4 9 E - 0 5

4 4 S L R T 1 1X 2 4 4 E - 0 6

4 5 S L R T y 1'y 5 . 5 E “ 0 6

4 6 S S R T y (1) 0 1 4 4 E - 0 4

4 7 S S R T y 0 1 3 . l E - 0 6

4 8 S S R T . 1 0 7 . 2 E - 0 6

4 9 S S R T 4 0 0 5 . 5 E - 0 4

5 . 0 S S R T 4 0 1 1 4 3 E - 0 5

5 1 S S R T 4 0 yy 3 . 3 E - 0 5

A.25

SYSTEM STATE CATEGORIESREC TY P E I N I T S P C FWS ECC PPC EFREQ

5 2 S S RT 3 1 0 0 2 . 4 E - 0 35 3 S S RT 1 0 1 6 . O E - 0 55 4 S S RT 1 0 y 1 . 6 E - 0 45 5 S S RT 77 1 1 0 2 . 6 E - 0 65 6 S S RT 0 0 8 . 7 E - 0 65 7 S L RT 4 0 0 0 6 . 9 E —0 45 3 S L RT 4 0 0 1 1 . 5 E - 0 55 9 S L RT 4 0 0 2 4 . 3 E —0 56 0 S S RT 4 4 0 0 3 . l E - 0 66 1 S S RT 4 1 0 0 1 . 6 E - 0 56 2 S L RT 5 Ci 0 C) 4 . 5 E - 0 46 3 S L RT 5 0 0 1 1 . l E - 0 56 4 S L RT 5 0 0 2 . S E - 0 56 5 S S RT 5 4 0 0 2 . 2 E - 0 66 6 S S RT 5 1 0 0 1 . 4 E - 0 56 7 S L RT 6 0 0 0 5 . O E - 0 46 3 S L RT 6 0 0 1 1 . 2 E - 0 56 9 S L RT 6 0 0 2 3 . l E - 0 57 0 S S RT 6 4 0 0 2 . 5 E - 0 67 1 S S RT 6 1 0 0 1 . 6 E —0 57 2 RES RT 9 9 9 9 9 9 9 9 1 . 9 E - 0 47 3 FW EMFW 0 1 0 0 S . 4 E - 0 27 4 FW EMFW 0 0 C) 1 , 4 E - 0 47 5 FW EMFW 0 y 0 1 2 . 9 E - 0 67 6 FW EMFW 0 y 0 2 6 . 3 E - 0 67 7 FW EMFW 0 4 (I) 0 5 . 5 E - 0 47 3 FW EMFW 0 4 0 1 1 . 3 E - 0 57 9 FW EMFW 0 4 0 3 . 3 E - 0 5SO FW EMFW 0 0 0 3 . l E - 0 48 1 FW EMFW 0 0 1 7 . 7 E - 0 63 2 FW EMFW 0 0 2 * 0 E - 0 5S 3 S S EMFW 1 1 0 0 1 . 2 E - 0 23 4 S S EMFW 1 1 0 1 2 . 9 E - 0 43 5 S S EMFW 1 1 0 /< 7 E ~ 0 43 6 S S EMFW 1 1 1 0 1 . 2 E - 0 58 7 S S EMFW 1 0 0 1 . 6 E - 0 58 3 S S EMFW I 4 0 0 3 . O E - 0 58 9 S S EMFW 1 4 0 3 . 5 E - 0 69C) S S EMFW 1 0 0 4 . 7 E - 0 59 1 S S EMFW 1 2 0 2 . 7 E - 0 69 2 S S EMFW 1 0 0 1 . 4 E - 0 49 3 S S EMFW 1 0 1 3 » I E —0 69 4 S S EMFW 1 0 7 . 2 E - 0 69 5 S 3 EMFW 77 1 0 0 1 . 3 E - 0 39 6 S S EMFW 0 1 0 1 3 . 2 E - 0 59 7 S S EMFW 1 0 y S . 4 E - 0 59 8 S S EMFW 0 1 1 0 1 . 4 E - 0 69 9 S S EMFW 7y 0 0 1 . 8 E - 0 6

1 0 0 S S EMFW 4 0 0 7 . 5 E - 0 61 0 1 S S EMFW 0 0 4 . 7 E - 0 61 0 2 S S EMFW 4 1 0 0 8 . 6 E - 0 6

A.26

SYSTEM STATE CATEGORIESREC T Y P E I N I T S P C FWS ECC PPC EFREQ

1 0 3 S S EMFW b 1 0 (1) 6 . 3 E - 0 6104- S S EMFW 6 1 0 0 7» 0E~( . )61 0 5 R ES EMFW 9 9 9 9 9 9 9 9 7 . 2 E - 0 51 0 6 S L L S L B 1 0 0 0 9 . 6 E - 0 41 0 7 S L L S L B 1 1 0 0 3 . O E - 0 51 0 8 S L L S L B 0 0 0 5 . 5 E - 0 61 0 9 RES L S L B 9 9 9 9 9 9 9 9 5 . 3 E - 0 61 1 0 S L S S L B 1 0 0 0 9 . O E - 0 31 1 1 S L S S L B 1 1 (I) 0 2 . 8 E - 0 41 1 2 S S S S L B 1 4 0 0 2 . 4 E - 0 61 1 3 S L S S L B 3T 0 0 0 6 * 3 E - 0 41 1 4 S L S S L B 0 0 1 1 . 5 E - 0 51 1 5 S L S S L B 0 0 4 . O E - 0 51 1 6 S L S S L B y 1 0 0 2 . 0 E - 0 51 1 7 S L S S L B y 1 0 1 . O E - 0 61 1 3 S L S S L B 4 0 0 0 6 . 5 E —0 61 1 9 RES S S L B 9 9 9 9 9 9 9 9 1 . 4 E - 0 51 2 0 NORM LOMFW (I) 0 0 (") 5 . 5 E - 0 11 2 1 LOCA LOMFW 0 0 0 1 1 . 4 E - 0 2

LOCA LOMFW 0 0 3 . 6 E - 0 21 2 3 FW LOMFW 0 “T (I) 0 2 . O E - 0 31 2 4 FW LOMFW 0 <;) 1 5 . l E - 0 51 2 5 FW LOMFW 0 0 o 1 . 3 E - 0 41 2 6 FW LOMFW 0 4 0 0 3 . 9 E - 0 31 2 7 FW LOMFW 0 4 0 1 9 . 5 E - 0 51 2 3 FW LOMFW 0 4 0 2 2 . 5 E - 0 41 2 9 S L LOMFW 1 0 0 (■; 8 . 4 E - 0 21 3 0 S L LOMFW 1 0 0 1 2 . l E - 0 31 3 1 S L LOMFW 1 0 0 5 . 5 E - 0 31 ^2. S L LOMFW 1 0 1 0 1 . I E - 0 41 S L LOMFW 1 o 1 1 2 . 7 E ~ 0 61 3 4 S L LOMFW 1 0 2 6 . 2 E - 0 61 3 5 s s LOMFW •i

J .T 0 0 3 , l E - 0 4

1 3 6 S S LOMFW 1 (I) 1 7 . 0 E - 0 61 3 7 S S LOMFW 1 ( j 1 . 6 E - 0 51 3 8 S S LOMFW 1 4 t j 0 5 , 9 E - 0 41 3 9 S S LOMFW 1 4 0 1 1 . 5 E - 0 51 4 0 S 3 LOMFW 1 4 (j 3 . 7 E - 0 51 4 1 S L LOMFW 0 0 0 9 . 8 E - 0 41 4 2 S L LOMFW 0 0 i 2 . 4 E - 0 51 4 3 SL LOMFW !Z 0 0 6 . 3 E - 0 51 4 4 S 3 LOMFW 2 0 0 3 . O E - 0 61 4 5 S S LOMFW 4 0 (Ij 5 . OE—0 61 4 6 S L LOMFW y 0 0 0 9 . 2 E - 0 31 4 7 S L LOMFW y 0 (j 1 2 . 3 E - 0 41 4 8 S L LOMFW y 0 0 6 . O E - 0 41 4 9 S L LOMFW y 0 1 0 1 . 2 E - 0 51 5 0 S S LOMFW y 0 0 3 . 4 E - 0 51 5 1 S S LOMFW y 0 1 . 8 E - 0 61 5 2 S S LOMFW 4 0 0 6 . 5 E - 0 51 5 3 S S LOMFW y 4 0 1 1 . 3 E - 0 6

A.27

SYSTEM STATE CATEGORIESREC T Y P E I N I T S P C FWS ECC PPC EFREQ

1 5 4 S S LOMFW 4 0 o 3 OE—0 61 5 5 S L LOMFW 4 0 0 0 8 . 3 E - 0 515ci S L LOMFW 4 0 0 4 , 3 E - 0 61 5 7 S L LOMFW 5 0 0 0 5 . 4 E - 0 51 5 8 S L LOMFW 5 0 (D 1 1 . 3 E - 0 61 5 9 S L LOMFW 5 0 o 3 . I E —Ci61 6 0 S L LOMFW 6 0 0 0 6 . l E - 0 51 6 1 S L LOMFW 6 0 0 1 1 . 5 E - 0 61 6 2 S L LOMFW 6 0 <l! 7* 3 . 5 E —Ci61 6 3 RES LOMFW 9 9 9 9 9 9 9 9 5 . 9 E - 0 51 6 4 LOCA S B L l o 0 0 0 7 . 6 E - 0 21 6 5 LOCA S B L l 0 0 0 1 1 . 9 E - 0 31 6 6 LOCA S B L l 0 0 0 5 . O E - 0 31 6 7 LOCA S B L l 0 (l! 1 0 9 . 9 E - 0 51 6 8 LOCA S B L l <;> 0 1 H

J. 2 . 4 E - 0 61 6 9 LOCA S B L l 0 0 1 5 . 5 E - 0 61 7 0 LOCA S B L l (I) 1 0 0 2 . 4 E - 0 31 7 1 LOCA S B L l 0 1 0 1 5 . 9 E “ 0 51 7 2 LOCA S B L l 0 0 o 1 , 6 E - 0 41 7 3 LOCA S B L l 0 1 1 0 2 . 5h.—0 61 7 4 LOCA S B L l X 0 0 6 . 6 E - 0 61 7 5 LOCA S B L l 0 4 C) 0 3 . l E - 0 51 7 6 LOCA S B L l Cj 0 Ci 8 , 7 E - 0 61 7 7 LOCA S B L l 1 0 0 0 1 . 2 E - 0 21 7 8 LOCA S B L l 1 0 0 1 2 . 9 E - 0 41 7 9 LOCA S B L l 1 C) 0 7 . 5 E - 0 41 3 0 LOCA S B L l 1 0 1 0 1 . 3 E - 0 51 8 1 LOCA S B L l 1 0 C) 1 . 7 E - 0 51 8 2 LOCA S B L l 1 4 0 0 7 . 7 E - 0 51 8 3 LOCA S B L l 1 4 0 2 3 . 6 E - 0 61 8 4 LOCA S B L l 1 1 0 C) 3 . 7 E - 0 41 8 5 LOCA S B L l 1 1 0 1 8 . 2 E - 0 61 3 6 LOCA S B L l 1 1 0 •-y 2 . l E - 0 54i G / LOCA S B L l 0 0 0 1 , 4 E - 0 41 8 8 LOCA S B L l 0 0 '•y, ■ / . 6 E - 0 61 8 9 LOCA S B L l lil 1 0 0 3 . 5 E - 0 61 9 0 LOCA S B L l 0 (I) 0 1 w 3 E - 0 31 9 1 LOCA S B L l 71 0 0 1 3 . O E - 0 51 9 2 LOCA S B L l “T 0 0 2 a . 3 E - 0 51 9 3 LOCA S B L l 0 i. (I) 1 . 4 E - 0 61 9 4 LOCA S B L l 17 3 0 Ci 1 . 9 E - 0 61 9 5 LOCA S B L l 4 0 Ci 7 . 8 E —Ci61 9 6 LOCA S B L l "T 1 0 0 4 . O E - 0 51 9 7 LOCA S B L l [T] 1 0 o 2 . l E - 0 61 9 3 LOCA S B L l 4 0 0 Ci 9 . l E - 0 6199 LOCA S B L l 5 0 0 C) 6 . 6 E - 0 62 0 0 LOCA S B L l 6 0 0 Cl 7 . 3 E - 0 62 0 1 RES S B L l 9 9 9 9 9 9 9 9 7 . 8 E - 0 52 0 2 LOCA S B L 2 <I) 0 0 C) 8 . 2 E - 0 32 0 3 LOCA S B L 2 0 0 1 C) i . O E - 0 52 0 4 LOCA S B L 2 0 1 0 0 2 . 6 E - 0 4

A.28

SYSTEM STATE CATESQRIESREC TYP E I N I T S P C FWS ECC PPG EF REQ

2 0 5 LOCA S B L 2 0 4 0 0 2 . 7 E —0 62 0 6 LQCA S B L 2 0 0 0 1 . O E - 0 62 0 7 LOCA S B L 2 1 0 0 0 1 . 2 E - 0 32 0 8 LQCA S B L 2 1 y 0 0 2 . l E - 0 62 0 9 LGCA> S B L 2 1 4 0 0 6 . 9 E - 0 62 1 0 LQCA S B L 2 1 i

J . 0 0 4 . O E - 0 5 -2 1 1 LQCA S B L 2 i iU 0 0 0 1 . 4 E - 0 52 1 2 LQCA S B L 2 r r (I) 0 0 1 . 4 E - 0 42 1 3 LOCA S B L 2 X 1 0 0 4 . O E - 0 62 1 4 RES S B L 2 9 9 9 9 9 9 9 9 1.. 8 E - 0 52 1 5 SGTR SGTR Cj 0 0 0 8 . 2 E - 0 32 1 6 SGTR SGTR 0 0 i

4 . 0 1 . O E - 0 52 1 7 SGTR SGTR 0 j . 0 0 2 , 6 E —0 42 1 8 SGTR SGTR 0 4 0 0 2 - 7 E - 0 62 1 9 SGTR SGTR 0 2 C) 0 1 . O E - 0 62 2 0 SGTR SGTR 1 <j 0 0 1 . 2 E - 0 3

1 SGTR SGTR 1 0 0 2 . l E - 0 6SGTR SGTR 1 4 0 0 6 . 9 E - 0 6SGTR SGTR 1 1 0 0 4 . O E - 0 5

2 2 4 SGTR SGTR 0 0 0 14 4 E - 0 52 2 5 SGTR SGTF'! 0 0 0 1 . 4 E - - 0 42 2 6 SGTR SGTR MT 1 0 44 O E - 0 6

RES SGTR 9 9 9 9 QQ 9 9 14 S E - 0 5NORM s r 0 0 0 0 7-4 6 E - 0 3LQCA S I 0 (I) 0 1 14 9 E - 0 4

2 3 0 LQCA S I ( I '■J 0 5 . : 0 E - 0 42 3 1 F W S I 0 1 0 0 2 . 4 E - 0 44^32 LQCA 3 1 0 .L 0 1 5 . 4 E - 0 62 3 3 LQCA 3 1 0 1 0 •■n 1 . 5 E - 0 52 3 4 F W 3 1 0 4 0 0 2 4 2 E - 0 62 3 5 S L S I 1 0 0 0 14 2 E - 0 32 3 6 S L 3 1 J . 0 0 1 24 3 E - 0 52 3 7 S L S I 1 0 - -r __r> cr

2 3 3 S S S I i. 4 0 i j 5 . 7 E - 0 62 3 9 S S S I 1 1 0 0 3 . 6 E - 0 52 4 0 S L S I 0 0 ( j 14 2 E - 0 52 4 1 S L S I 0 0 0 14 3 E - 0 42 4 2 S L S I 0 0 1 3 4 1 E —0 62 4 3 SL S I 0 0 2 7 4 i ' c . ~ 0 62 4 4 S S S I y 1 0 0 3 . 3 E - 0 62 4 5 RES S I 9 9 9 9 99 9 9 3 4 9 E - 0 5

A.29

A.3 General Tab l e o f Vo s e l ThronKh-W>ll Crack F r e qpcncv Rest t l t$

I t s h o u l d b e n o t e d t h a t a r e v i e w o f t h e a s s i g n m e n t o f r e p r e s e n t a t i v e f r a c t u r e - m e c h a n l c s c a s e s t o e a c h s e q u e n c e r e v e a l e d b o t h c o n s e r v a t i v e an d n o n - c o n s e r v a t i v e a s s i g n m e n t s . I t was t h e o p i n i o n o f t h e a n a l y s t s t h a t I n g e n e r a l c o n s e r v a t i v e an d s o m e t im e s o v e r l y c o n s e r v a t i v e a s s i g n m e n t s w e re m ade. T h i s was p a r t i c u l a r l y t r u e f o r t h e a s s i g n m e n t o f a f r a c t u r e m e c h a n ic s c a s e t o t h e r e s i d u a l c a s e s . An a t t e m p t was made t o r e c o n s t r u c t t h e t a b l e a n d t h u s r e d u c e t h e l e v e l o f c o n s e r v a t i s m I n v o l v e d I n t h i s p o r t i o n o f t h e a n a l y s i s . U n f o r t u n a t e l y , t h e r e was l i t t l e t h a t c o u l d b e d o n e w i t h o u t p e r f o r m i n g a d d i t i o n a l t h e r m a l - h y d r a u l i c a n d / o r f r a c t u r e - m e c h a n l c s c a l c u l a ­t i o n s . I n a d d i t i o n t h e r e s o l u t i o n o f t h e few n o n - c o n s e r v a t i v e a s s i g n m e n t s l e d t o a h i g h e r o v e r a l l v e s s e l f a i l u r e v a l u e . Thus I n t r y i n g t o r e d u c e b o t h t h e c o n s e r v a t i v e an d n o n - c o n s e r v a t i v e b i a s e s I n t r o d u c e d by t h e a s s i g n ­m e n t o f f r a c t u r e - m e c h a n l c s c a s e s , we p r o d u c e d a s e t o f d a t a w h ic h was c l e a r l y b i a s e d I n t h e c o n s e r v a t i v e d i r e c t i o n . T h i s d a t a c a n b e fo u n d In A p p e n d ix F a n d I s p r e s e n t e d s i n c e I t I n c l u d e s t h e e l i m i n a t i o n o f some o f t h e n o n - c o n s e r v a t i v e b i a s e s fo u n d I n t h e a n a l y s i s e v e n th o u g h I t f a l l s t o a d d r e s s t h e l a r g e r c a t e g o r y o f c o n s e r v a t i v e b i a s e s .

A.30

REC TYPE INIT SPC FWS ECC RFC EFREQ TRANS HF TRANS* TFREC P (F ;T ) P(TWC)1 NORN RT 0 0 0 0 5 .0£t0C i NONE l.O E+00 0 5.0E+00 O.OE+OO O.OE+OO2 FH RT 0 1 0 0 1 .6 E -0 1 QVRFD3 l.O E +00 16 1 .6 E -0 1 l.O E -0 7 1.6E-0B3 FW RT 0 3 0 I 4 .9 E -0 4 FSE35 9 .9 E -0 1 15 4 .9 E -0 4 l.O E -0 7 4 .9 E -1 14 FW RT 0 3 0 1 4 .9 E -0 4 P5BG4 l.O E -0 2 14 4 .9 E -0 6 1 .3 E -0 3 6 .2 E -0 95 FW RT 0 3 0 1L 3 .0 E -0 5 P3BG5 9 .9 E -0 1 15 3 .0 E -0 5 l.O E -0 7 3 .0 E -1 26 FW RT ■1 ’ . 'J 0 J. 3 .0 E -0 5 FSB84 l .O E -0 2 14 3 .0 E -0 7 1 .3 E -0 3 3 .3 E -1 07 FW RT 0 4 0 0 1 .9 E -0 3 NQNE 9 .9 E - 0 I 0 1 .5 E -0 3 O.OE+OO O.OE+OO8 FW RT 0 4 0 0 1 .9 E -0 3 QVRFDE l.O E -0 2 21 1 .9 E -0 5 1 .4 E -0 6 2 .7 E -1 19 FW RT 0 4 0 0 1 .9 E -0 3 GVRFBT 3 .6 E -0 3 22 6 .8 E -0 6 l.O E -0 7 6 . B E-13

10 FW RT 0 4 0 1 4 .7 E -0 5 NONE 9 .9 E -C 1 0 4 .7 E -C 5 O.OE+OO O.OE+OO11 FW RT 0 4 0 1 4 .7 E -0 5 00RFD6 1 .0 E -0 2 21 4 .7 E -0 7 1 .4 E -0 6 6 .6 E -1 312 FW RT 0 4 0 i 4 .7 E -0 5 QVRFD7 3 .6 E -0 3 LL 1 .7 E -0 7 l.O E -0 7 1 .7 E -1 413 FW RT 0 4 0 ni. 1 .3 E -0 4 NONE 9 .9 E -0 1 0 1 .3 E -0 4 O.OE+OO O.OE+OO14 FW RT 0 4 0 - 1 .3 E -0 4 OVRFQt. l .O E -0 2 21 1 .3 E -0 6 1 .4 E -0 6 l .S E -1 215 FW RT 0 4 0 V 1 .3 E -0 4 OOR:FB7 3 .6 E -0 3 22 4 .7 E -0 7 l.O E -0 7 4 .7 E -1 416 FW RT 0 2 0 0 5 .3 E -0 4 NIN 9 .9 E -0 1 98 5 .7 E -0 4 l.O E -0 7 5 .7 E -1 117 FW RT 0 2 0 0 5 .0 E -0 4 INEL6 l.O E -0 2 56 S .S E -O i 4 .2 E -0 7 2 .4 E -1 218 FW RT y L 0 i 1 .4 E -0 5 TBVG2 9 .9 E -0 1 2 1 .4 E -0 5 l.O E -0 7 1 .4 E -1 219 FW RT 0 2 0 I 1 .4 E -0 5 TBV66 l .O E -0 2 6 1 .4 E -0 7 1 .7 E -0 6 2 .4 E -1 320 FW RT 0 2 0 2 3 .7 E -0 5 TBVG2 9 .9 E -0 1 nL 3 .7 E -0 5 l.O E -0 7 3 .7 E -1 221 FW RT 0 2 0 nL. 3 .7 E -0 5 TBOGE l,C E -0 2 6 3 .7 E -0 7 I .7 E -0 6 6 .3 E -1 322 SL RT i 0 0 0 6 .9 E -0 1 TBVG2 9 .9 E -0 1 ni. 6 .3 E -0 1 l.O E -0 7 6 .B E -0823 SL RT 0 0 0 6 .9 E -0 1 TBVGl l .O E -0 2 1 6 .9 E -0 3 4 .0 E -C 7 2 .8 E -0 924 SL RT 1 0 0 1 1 .7 E -0 2 PSBG5 9 .9 E -0 1 15 1 .7 E -0 2 l.O E -0 7 1 .7 E -0 925 5L RT 1 0 0 1 1 .7 E -0 2 TBV66 l .O E -0 2 6 1 .7 E -0 4 1 .7 E -0 6 2 .9 E -1 026 EL RT 1 0 0 nL 4 .5 E -0 2 P3BG5 9 .9 E -0 1 15 4 .5 E -0 2 l.O E -0 7 4 .5 E -0 927 SL RT 1 0 0 4 .5 E -0 2 TBVG6 l.O E -0 2 6 4 .5 E -0 4 1 .7 E -0 6 7 .7 E -1 028 SL RT 1 0 1 0 9 .0 E -0 4 TB'v'G2 9 .9 E -0 1 2 3 .9 E -0 4 l.C E -0 7 8 .9 E -1 129 SL RT 1 0 i 0 9 .0 E -0 4 TBVSl l .O E -0 2 1 9 .0 E -0 6 4 .0 E -0 7 3 .6 E -1 230 SL RT ! 0 1 1 2 .2 E -0 5 FSBG5 9 .9 E -0 1 15 2 .2 E -0 5 i.G E -0 7 2 .2 E -1 231 SL RT i 0 1 1 2 .2 E -0 5 TSVG6 l.O E -0 2 6 2 .2 E -0 7 1 .7 E -0 6 3 .7 E -1 332 SL RT 1 0 1 nL 5 .6 E -0 5 PSSG5 9 .9 E -0 1 15 5 .5 E -0 5 l.O E -0 7 5 .5 E -1 233 SL R' 1 (I 1 ni. 5 .6 E -0 5 TBVG6 l.O E -0 2 6 5 .6 E -0 7 1 .7 E -0 6 9 .5 E -1 334 SS R;T 1 3 0 1 2 . SE -05 PSBG5 9 .9 E -0 1 15 2.,SE-05 l.O E -0 7 2 .8 E -1 235 S3 RT 1 3 0 1 2 .8 E -0 5 TBVG6 l.O E -0 2 2 .3 E -0 7 1 .7 E -0 6 4 .S E -1 336 SS RT 1 3 c 2 7 .7 E -0 5 PSBG5 9 .9 E -0 1 15 7 .6 E -0 5 l.O E -0 7 7 .6 E -1 237 S3 RT 3 2 7 .7 E -0 5 TBV66 l .O E -0 2 e 7 .7 E -0 7 1 .7 E -0 6 1 .3 E -1 238 SS RT 1 4 (! 5 .0 E -0 3 TEvG2 9 .9 E -0 1 'NL 5 .0 E -0 3 l.O E-O T 5 .0 E -1 039 SS RT 1 4 0 5 .0 E -0 3 0VRFD4 l.O E -0 2 21 5 .0 E -0 5 1 .4 E -0 6 7 .0 E -1 140 SS RT 1 4 0 0 5 .0 E -0 3 CVRFD7 3 .6 E -0 3 ■”.nLL l .B E -0 5 1 .OE-07 l .S E -1 241 SS RT 1 4 fl 1 1 .2 E -0 4 PSBG5 9 .9 E -0 1 15 1 .2 E -0 4 l.O E -0 7 1 .2 E -1 142 SS RT 1 4 c 1 1 .2 E -0 4 0VRFD6 l.O E -0 2 21 1 .2 E -0 6 1 .4 E -0 6 1 .7 E -1 243 SS RT 1 4 0 1 i .2 E - 0 4 0VRFD7 3 .6 E -0 3 nnLL 4 .3 E -0 7 l.O E -0 7 4 .3 E -1 444 SS RT 4 0 2 3 .2 E -0 4 PSB85 9 .9 E -0 1 15 3 .2 E -0 4 l.O E -0 7 3 .2 E -1 145 SS RT 1 4 0 L 3 .2 E -0 4 0VRFD6 l.O E -0 2 21 3 .2 E -0 6 1 .4 E -0 6 4 .5 E -1 246 SS RT 1 4 0 nL 3 .2 E -0 4 0VRFD7 3 .6 E -0 3 22 1 .2 E -0 6 l.O E -0 7 1 .2 E -1 347 SS RT 1 4 1 0 4 .4 E -0 6 TBVG2 9 .9 E -0 1 2 4 .4E -C 6 l.O E -0 7 4 .4 E -1 348 SS RT 1 4 1 0 4 .4 E -0 6 0VRTD6 l.O E -0 2 21 4 .4 E -0 B 1 .4 E -0 6 6 .2 E -1 449 SS RT 1 4 1 0 4 .4 E -0 6 QVRFD7 3 .6 E -0 3 22 1 .6 E -0 8 l.O E -0 7 1 .6 E -1 550 SL RT 1 1 0 2 .2 E -0 2 TBVG3 9 .S E -0 1 3 2 .2 E -0 2 l.O E -0 7 2 .2 E -0 951 SL RT 1 0 2 .2 E -0 2 TSVG4 l.O E -0 2 4 2 .2 E -0 4 2 .0 E -0 3 4 .4 E -0 752 SS RT 1 1 0 1 5 .4 E -0 4 PSB65 P .9 E -0 1 15 5 .3 E -0 4 1 .0 E -0 7 5 .3 E -1 153 SS RT 1 1 0 I 5 .4 E -0 4 T3VG6 l.O E -0 2 6 5 .4 E -0 6 1 .7 E -0 6 9 .2 E -1 2 .

A.31

REC TYPE !NIT SPC FWS ECC PPC EFREQ TRAfiS HF TRAN.SI TFREQ PIFIT) P(TKC)54 SS RT I 1 0 2 1.4E-03 PSBG5 9.9E-01 15 1.4E-03 l.OE-07 1.4E-1055 ES RT 1 1 0 L 1.4E-03 TBVG6 l.OE-02 6 1.4E-C5 1.7E-06 2.4E-1156 SS RT I 1 <

i 0 2.8E-V5 TBVG3 9.9E-01 >7L 2.8E-05 I.OE-07 2.8E-1257 ES RT 1 1 1 0 2.eE-05 TBVS4 l.OE-02 4 2.8E-C7 2.CE-03 5.6E-1058 SS RT 1 nL 0 0 3.8E-05 TBVG3 9.9E-01 3 3.7E-05 l.OE-07 8.7E-1259 BS RT 1 L 0 0 8.8E-05 T8VE4 1.0E-C2 4 5.FF-07 2.0E-03 1.8E-0960 S3 RT 1 nL 0 1 2.2E-06 P3BG5 9.9E-01 15 2.2E-06 l.OE-07 2.2E-i361 SS RT 1 r*

L 0 1 2.2E-06 TBv'G6 l.OE-02 6 2.2E-08 1.7E-06 3.7E-1462 S3 RT 1 2 0 ' ) 5.0E-06 PSBG5 9.9E-01 15 5.0E-06 l.OE-07 5.0E-1363 SS RT ; L 0 nL 5.0E-06 TBVG6 l.OE-02 6 5.0E-0E 1.7E-06 3.5E-1464 SL RT nL 0 0 0 8.2E-03 TBVG2 9.9E-01 •7 8.1E-03 l.OE-07 8.1E-1065 SL RT nL 0 0 0 S.2E-03 TB9G1 l.OF-02 1 8.2E-C5 4.0E-07 3.3E-1166 SL RT <*i

L. 0 0 1 2.0E-04 PSBG5 9.9E-01 15 2.0E-04 l.OE-07 2.0E-1167 SL RT I 0 0 I 2.0E-04 TB7G6 l.OE-02 6 2.0F-06 1.7E-06 3.4E-1268 SL RT L 0 0 ■J

i . 5.3E-04 PSBG5 9.9E-01 15 5.2E-04 l.OE-07 5.2E-1169 SL RT >-y 0 0 nL 5.3E-04 TBVGA l.OE-02 6 5.3E-06 1.7E-06 9.0E-1270 SL RT nL 0 1 0 9.2E-06 TBVG2 9.9E-0i 2 9.1E-06 l.OE-07 9 . IE-1371 EL RT nL 0 1 0 9.2E-04 TBVGI l.OE-02 1 9.2£-oe 4.0E-07 3.7E-1472 SS RT 2 3 0 0 1.2E-05 TBVG2 9.9E-01 2 1.2E-05 l.OE-07 1.2E-1273 SS RT n 0 0 1.2E-05 LANL7 l.OE-02 41 1.2E-07 1.8E-03 2.2E-1074 SS RT nL 4 0 0 5.5E-05 TBVG2 9.9E-01 7L 5.4E-05 l,0E-07 5.4E-1275 SS RT •TI 4 0 0 5.5E-05 QVRFD6 l.OE-02 21 5.5E-07 1.4E-06 7.7E-1376 SS RT n 4 0 0 5.5E-05 QVRFD7 3.6E-03 22 2.0E-07 l.OE-07 2.0E-1477 SS RT -Ii 4 0 n

L 2.6E-06 PSBG5 9.9E-01 15 2,6E-06 1.0E-C7 2.6E-1373 S3 RT ni 4 0 n 2.6E-06 0VRFD6 l.OE-02 21 2.6E-03 1.4E-06 3.6E-1479 SS RT 4 0 L 2=6£-06 OVRFDT 3.6E-03 22 5.4E-09 l.OE-07 9.4E-1680 SS RT nL 1 '■) 0 2.6E-04 T3VG3 9,9E-0i 3 2.6E-04 l.OE-07 2.6E-1181 SS RT '*1 1 0 0 2,6£-04 TBVG4 i.OE-02 4 2.6E-06 2.0E-03 5.2E-0982 SS RT -7 1 0 1 5.8E-0.fi P3SG5 9.9E-0i 15 5.7E-06 l.OE-07 5.7E-1383 SS RT n 1 0 I 5.EE-06 TBV66 l.OE-02 6 5.3E-CS 1.7E-06 9.9E-I484 SS RT T I 0 nL 1.3E-05 P3B65 9.9E-01 15 1.3E-05 l.OE-07 1.3E-1285 SS RT 7 1 0 2 1.3E-05 TBVG6 l.OE-02 6 1.3E-07 1.7E-06 2.2E-1386 SL RT 7 0 0 0 7.6E-02 TBVG3 9.9E-C1 3 7.5E-02 1.0E-07 7.5E-0987 SL RT 0 0 0 7=6E-02 TBVG5 l.OE-02 5 7.6E-04 5.2E-06 4.0E-0983 SL RT 7 0 0 1 1.9E-03 TBV68 9.9E-01 3 1.9E-03 l.OE-07 1.9E-1089 SL RT 7 0 0 I 1.9E-03 TEVGIO 1.0E-C2 10 1.9E-05 l.OE-05 1.9E-1090 SL RT 7■J 0 0 5.0E-03 TBVG8 9.9E-C1 8 5.0E-03 .l.OE-07 5.0E-1091 SL RT T 0 0 2 5.0E-03 TBVGIO l.OE-02 10 5.0E-05 l.OE-05 5.0E-1092 SL RT 7 0 1 0 9.9E-05 TEV6S 9.9E-0I a 9.3E-05 i.OE-07 9.3E-1293 SL RT 7 0 1 0 9.9E-05 TBVG5 l.OE-02 5 9.9E-07 5.2E-06 5.1£-1294 SL RT 7

•J 0 1 1 2.4E-06 TBVG8 9.9E-01 8 2.4E-06 l.OE-07 2.4E-1395 SL RT 3 0 1 1 2.4E-06 TSVGIO l.OE-02 10 2.4E-08 l.OE-05 2.4E-1396 SL RT 7 0 1 nL 5.5E-06 TBVG8 9.9E-01 8 5.4E-06 l.OE-07 5.4E-1397 SL RT 3 0 1 2 5.5E-06 TBVGIO l.OE-02 10 5.5E-08 l.OE-05 5.5E-1398 S3 RT 3 3 0 0 1.4E-04 TBV62 9.9E-01 7i. 1.4E-04 l.OE-07 1.4E-1199 SS RT 7 3 0 0 1.4E-04 LANL7 l.OE-02 41 1.4E-06 1.3E-03 2.5E-09

100 SS RT 3 3 0 1 3 . lE-06 PSBG5 9.9E-01 15 Z, lE-Oi l.OE-07 3.1E-13101 SS RT 3 3 c I 3.1E-06 TEVE6 1.OE-02 6 3.1E-03 1.7E-06 5.3E-14102 S3 RT 7

■J 3 0 nL 7.2F-06 PSBGS 9.9E-01 15 7.1E-06 l.OE-OT 7.1E-13103 S3 RT 7 7

• J 0 nL 7.2E-06 TBVG6 l.OE-02 6 7.2E-08 1.7E-06 1.2E-13

104 SS RT 7 4 0 0 5.5E-04 TBVG2 9.9E-01 7L 5.4E-04 l.OE-07 5.4E-11105 SS RT 7

•J 4 0 0 5.5E-04 QVRF06 l.OE-02 21 3.5E-06 1.4E-06 7.7E-12106 SS RT 1 4 0 0 5.5E-04 0VRFD7

A . 32

3.6E-03 22 2.0E-06 l.OE-07 2.0E-13

REC TYPE INIT SRC FHS ECC PPC EFREQ TRANS HF TRftNSi TFREQ P(FIT) P(THC)107 SS RT 3 4 0 1 1.3E-05 PSBS5 9.9E-01 15 U3E-05 l.OE-07 1.3E-12i08 ccuo RT 3 4 0 1 1.3E-05 QVRFD6 l.OE-02 21 1.3E-07 1.4E-06 1.8E-13109 SS RT 3 4 0 1 1.3E-05 OVRFDT 3.4E-03 22 4.7E-03 l.OE-07 4.7E-15110 SS RT T■J 0 TL 3.3E-05 FSEG5 9.9E-01 15 3.3E-05 l.OE-07 3.3E-12111 SS RT 3 4 0 nto 3.3E-05 0VRFD6 l.OE-02 21 3.3E-07 1.4E-06 4.4E-13112 SS RT 3 4 0 n

i. 3.3E-05 0VRFD7 3.4E-03 22 1.2E-07 l.OE-07 1.2E-14113 SS RT T•J 1 0 0 2.4E-03 TBVG3 9.9E-01 8 2.4E-03 l.OE-OT 2.4E-10114 SS RT 3 0 0 2.4E-03 TBVG9 l.OE-02 9 2.4E-05 2.0E-03 4.EE-08115 SS RT 3 1 0 1 6.0E-05 TBVG8 9.9E-01 e 5.9E-05 l.OE-07 5.9E-12116 SS RT 7 1 0 1 4.0E*05 TBVGIO l.OE-02 10 6.0E-07 l.OE-05 6.0E-12117 SS RT 7 1 0 2 1.4E-04 TBVG8 9.9E-01 3 1.4E-C4 l.OE-07 1.6E-11118 SS RT 7, 1 0 n 1.4E-04 TBVGIO l.OE-02 10 1.6E"04 l.GE-05 1.6E-11119 SS RT 7

■J 1 1 0 2.4E-04 TBVG9 9.9E-0! 3 2.4E-06 i.OE-07 2.6E-13120 ecij-j RT 3 1 1 0 2.4E-04 TBVG5 l.OE-02 5 2.6E-08 5.2E-06 l.«E-13121 SS RT 7 2 0 0 3.7E-04 TBVG3 9.9E-01 3 3.4E-06 l.OE-07 3.6E-13122 SS RT 7, 0 0 e.7E-04 TBVG4 l.OE-02 4 8.7E-0G 2.0E-03 1.7E-10123 SL RT 4 0 0 4.9E-04 TBVG2 9.9E-01 -“tto 4.3E-U4 l.OE-07 4.8E-11124 SL RT 4 0 0 0 4.9E-04 TBVGl l.OE-02 1 6.9E-06 4.0E-07 2.BE-12125 SL RT 4 0 0 ! 1.5E-05 TBVG2 9.9E-01 2 1.5E-05 l.OE-07 1.5E-12126 SL RT 4 0 I) 1 1.5E-05 TBVGIO l.OE-02 10 1.5E-07 l.OE-05 1.5E-12127 SL RT 4 0 0 2 4.3E-05 TBVG2 9.9E-01 n 4.3E-05 l.OE-07 4.3E-12128 SL RT 4 0 2 4.3E-05 TBVGIO i.OE-02 10 4.3E-07 l.OE-05 4.3E-12129 S3 RT i 4 0 0 3 . lE-06 TBVG2 9.9E-01 2 3.iE-06 l.OE-07 3.1E-13130 SS RT 4 0 0 3.1E-04 QVRFB4 l.CE-02 21 3.1E-08 1.4E-06 4.3E-14131 S3 RT 4 4 0 0 3.1E-06 QVRFD7 3.4E-03 22 l.lE-03 l.OE-07 l.lE-15132 SS RT 4 1 0 0 1.4E-05 TBVG2 9.9E-01 nL 1.6E-05 l.OE-07 1.4E-12133 SS RT 4 1 0 0 1.4E-05 TBVG9 l.OE-02 9 1.6E-07 2.0E-03 3.2E-10134 SL RT D (I 0 0 4.5E-04 TBVG2 9.9E-01 2 4.5E-04 i.OE-07 4.5E-11135 SL RT C

J 0 0 0 4.5E-04 TBVG5 l.OE-02 5 4.5E-06 5.2E-06 2.3E-U136 SL RT r

J 0 0 1 l.lE-05 TBVG2 9.9E-01 nL l.lE-05 l.OE-0’ l.lE-12137 SL RT 5 0 0 1 l.lE-05 TBVGIO l.OE-02 10 l.lE-07 l,0E-05 l.lE-12138 SL RT r•J 0 0 Tto 2;,BE-05 TBVG2 9.9E-0! 2 2.SE-05 l.OE-07 2.8E-12139 SL RT c

•J 0 0 1 2.SE-05 TBVGIO l.OE-02 10 2.SE-07 l.OE-05 2.3E-12140 3E RT r•J 4 0 0 2.2E-04 TBVG2 9.9E-01 2 2.2E-04 l.OE-07 2.2E-13141 SS RT 5 4 0 0 2.2E-06 0VRFD4 l.OE-02 21 2.2E-03 1.4E-06 3.1E-14142 SS RT J 0 0 2.2E-04 OVRFB? 3.4E-03 22 7.9E-09 l.OE-07 7.9E-16143 SS RT r

w 1 fl 0 1.4E-05 TBVG2 9.9E-01 1.4E-05 l.OE-07 1.4E-12144 SS RT z

J 1 0 0 1.4E-05 TBVG9 l.OE-02 9 1.4E-07 2.0E-03 2.SE-10145 SL RT 0 0 0 5.0E-04 HSLEl 9.9E-01 26 5.0E-04 6.2E-04 3.1E-07146 SL RT 6 0 0 0 5.0E-04 T3VG9 l.OE-02' 9 5.CE-04 2.0E-03 1.0E-C8147 SL RT 4 0 (I 1 1.2E-05 I1SLB7 9.9E-01 32 1.2E-05 6.2E-0i 7.4E-09148 SL RT 4 0 0 1 1.2E-05 TBVG9 l.OE-02 9 1.2E-07 2.CE-03 2.4E-10149 SL RT 4 0 0 2 3.1E-05 NSLB7 9.9E-01 s / i 3.1E-05 4.2E-04 i.9E-08150 SL RT 4 0 0 n

ii. 3.1E-05 TBVG9 i.OE-02 9 3.1E-07 2.0E-03 6.2E-10151 SS RT s 4 0 0 2.5E-06 fISLBl 9.9E-01 26 2.5E-06 4.2E-04 1.5E-09152 SS RT 4 4 0 0 2.5E-04 GVRFD4 t.OE-02 21 2.5E-03 1.4E-04 3.5E-14153 SS RT 4 4 0 0 2.5E-04 OVRFDT 3.4E-03 22 9.0E-09 l.OE-07 9.0E-14154 SS RT 4 1 0 0 1.4E-05 MSLS7 9,9E-0! •yn

• J i 1.4E-05 4.2E-04 9.GE-09155 SS RT 4 1 0 0 1.4E-05 TBVG9 1.OE-02 9 1.6E-07 2.0E-03 3.2E-10156 RES RT 9R 99 99 99 1.9E-04 DEF I. OE+OO 99 1.9E-04 S.4E-03 l.OE-06157 FH EflFH 0 1 0 0 3.4E-02 0VRFD3 l.OE^O 13 8.4E-02 l.OE-07 6.4E-09158 FH ENFH 0 3 0 0 1.4E-04 NIN 9.9E-01 98 1.4E-04 1.0E-C7 l.JE-11159 FH ELIFH 0 T

•J 0 0 1.4E-04 INEL3

A . 33

l.OE-02 53 1.4E-06 l.OE-07 1.4E-13

REC TYPE INIT SPC FWS ECC PPG EFRE3 TRANS HF TRANSit TFREQ P(F!T! P(TWC)160 FW ENFW 0 3 0 1 2.9E-06 PSBGS 9.9E-01 IS 2.9E-06 1.Ct-07 2.9E-13161 FW ENFH 0 3 0 1 2.9E-06 PSBG4 l.OE-02 14 2.9E-08 1.3E-03 3.7E-11'62 FW EHFH 0 3 0 2 6.St-06 PSBGS 9.9E-01 IS 6.7E-06 l.OE-07 6.7E-13163 FW EHFW 0 3 0 2 6.8E-06 PSBG4 l.OE-02 14 6.8E-08 1.3E-03 3.6E-11164 FW EflFW **» 4 0 0 5.5E-04 T3VG2 9.9E-01 n

L 5.4E-04 l.OE-07 5.4E-11165 FH EMFW 0 4 0 0 J.5E-04 0ORFD6 l.OE-02 21 5.SE-06 1.4E-06 7.7E-12166 FW EHFW 0 4 0 0 5.5E-04 OVRFDT 3.6E-03 n n 2.0E-06 1. 0E.-07 2.0E-13167 FW EHFW 0 4 0 1 1.3E-05 PSBG5 9.9E-01 15 1.3E-05 1..0E-07 1.3E-1216S FW EHFW 0 4 0 1 1.3E-05 QVRFD6 l.OE-02 21 1.3E-07 1.4E-06 1.8E-13169 FW EHFW 0 4 0 1 1.3E-05 QVRFD7 3.6E-03 22 4.7E-08 l.OE-07 4.7E-15170 FW EHFW 0 4 0 2 3.3E-05 PSBGS 9.9E-01 15 3.3E-05 l.OE-07 3.3E-12171 FW EHFW 0 4 0 2 3.3E-05 0VRFD6 l.OE-02 21 3.3E-07 1.4E-06 4.6E-13172 FW EHFW 0 4 0 2 3.3E-05 OVRFDT 3.6E-03 1.2E-07 l.OE-OT I.2E-14173 FH EHFW 0 2 0 0 3.1E-04 TBVG2 9.9E-01 2 3.1E-04 l.OE-07 3,1E-11174 FH EHFW 2 0 0 3 . lE-04 TBVGl l.OE-02 1 3.1E-06 4.0E-07 1.2E-12175 FW EHFW 2 0 1 7.7E-06 TBV32 9.9E-01 *5 7.6E-06 l.OE-07 7.6E-13176 FH EHFW 0 2 0 1 7.7E-06 TBVG6 l.OE-02 6 7.7E-03 1.7E-06 1.3E-13177 FH EHFW 2 0 2 2.0E-05 TBVG2 9.9E-01 n 2.0E-OS l.OE-07 2.0E-12178 FW EHFW 2 0 2 2.0E-05 TBVG6 l.OE-02 6 2.0E-07 1.7E-06 3.4E-13179 SS EHFW 1 1 0 0 1.2E-02 TBVG2 9.9E-01 2 1.2E-02 l.OE-07 1.2E-09180 SS EHFW 1 1 0 0 1.2E-02 TBVGl l.OE-02 1 1.2E-04 4.0E-07 4.8E-11181 SS EHFW 1 0 1 2.9E-04 PSBGS 9.9E-01 IS 2.9E-04 l.OE-07 2.9E-11182 SS EHFW 1 1 0 1 2.9E-04 TBVG6 l.OE-02 6 2.9E-06 1.7E-06 4.9E-12183 SS EHFW I 1 0 2 7.7E-04 PSBGS 9.9E-01 15 7.6E-04 1.0E-07 7.6E-11184 SS EHFW 1 0 2 7.7E-04 TBV66 l.OE-02 6 7.7E-06 1.7E-06 1.3E-U185 SS EHFW 1 1 1 0 1.2E-05 TBVG2 9.9E-01 L 1.2E-05 l.OE-07 1.2E-12186 SS EHFW 1 1 1 0 1.2E-05 TBVGl l.OE-02 fi 1.2E-07 4.0E-07 4.8E-14187 SS EHFW 1 3 0 0 1.6E-05 TBVG2 9.9E-01 L 1.6E-0S l.OE-07 1.6E-12IBB SS EHFW 1 3 0 0 1.6E-05 LANL7 l.OE-02 41 1.6E-07 1.8E-03 2.9E-10189 SS EHFW 1 4 0 0 e.OE-05 TBV62 9.9E-01 2 7.9E-05 l.Ot-07 7.9E-12190 SS EHFW 1 4 0 0 8.0E-05 QVRFD6 l.OE-02 21 3.0E-07 1.4E-06 l.lE-12191 SS EHFW 1 4 0 0 8.0E-05 0VRFD7 3.6E-03 22 2.9E-07 l.OE-07 2.9E-14192 SS EHFW 1 4 0 2 3.5E-06 PSBGS 9.9E-01 IS 3.SE-06 l.OE-07 3.5E-13193 SS EHFW 1 4 0 2 3.5E-06 0VRFB6 l.OE-02 21 3.5E-08 1.4E-06 4.9E-14194 SS EHFW 1 4 0 2 3.5E-06 OVRFDT 3.6E-03 22 1.3E-03 l.OE-07 1.3E-15195 SS EHFW 1 2 0 0 4.7E-05 TBVG3 9.9E-01 3 4.7E-05 l.OE-07 4.7E-12196 SS EHFW 1 2 0 0 4.7E-05 TBVS4 l.OE-02 4 4.7E-07 2.CE-03 9.4E-10197 SS EHFW 1 2 0 2 2.7E-06 PSBGS 9.9E-01 15 2.7E-06 l.OE-07 2.7E-13198 SS EHFW 1 2 0 2 2.7E-06 TBVG6 l.OE-02 6 2.7E-C8 1.7E-06 4.6E-14199 SS EHFW 2 1 0 0 1.4E-04 TSVG3 9.9E-01 T 1.4E-04 l.OE-07 1.4E-11200 SS EHFW 2 1 0 0 1.4E-04 TEVG4 1.0E-02 4 1.4E-06 2.0E-03 2.8E-09201 SS EHFW n ■

L 1 0 1 3.1E-06 PSBGS 9.9E-01 15 3.1E-06 l.OE-07 3.1E-13202 cc EHFW 2 1 0 1 3 . lE-06 TBVG6 l.OE-02 6 3.1E-03 1.7E-06 5.3E-14203 SS EHFW o

L 1 0 2 7.2E-06 PSB65 9.9E-01 15 7 . lE-06 l.OE-07 7.1E-13204 SS EHFW n

L 1 0 2 7.2E-06 TBVG6 l.OE-02 6 7.2E-08 1.7E-06 1.2E-13205 SS EHFW 7 1 0 0 1.3E-03 TBV68 9.9E-01 3 1.3E-03 l.OE-07 1.3E-10206 SS EHFW 3 1 0 0 1.3E-03 TBVG9 l.OE-02 9 1.3E-05 2.0E-03 2.6E-08207 SS EHFW T 1 0 1 3.2E-05 TEOGS 9.9E-01 8 3.2E-05 l.OE-07 3.2E-12203 SS EHFW 7 1 0 I 3.2E-05 TBVGIO l.OE-02 10 3.2E-07 l.OE-05 3.2E-12209 £5 EHFW 7 1 0 2 S.4E-C5 TBVG8 9.9E-01 8 8.3E-05 l.OE-07 8.3E-12210 SS EHFW 7

•J 1 0 2 8.4E-05 TBVGIO l.OE-02 10 8.4E-07 l.OE-05 S.4E-12211 SS EHFW ,S 1 1 0 1.4E-06 TBVG8 9.9E-01 8 1.4E-06 l.OE-07 1.4E-13212 SS EHFW 7 1 1 0 1.4E-06 TBVG9

A. 34

l.OE-02 9 1.4E-08 2.0E-03 2.8E-11

REC TYPE INIT SPC FHS ECC PPC EFRES TRANS HF TRANS4 TFREQ PIF T) P(THC)213 SS EftFH 3 3 0 0 l.BE-06 TBVG2 9.9E-01 n i.BE-04 l.CE-07 1.8E-13214 SS EJ1FH T

■J 3 0 0 1.8E-06 LANL7 l.OE-02 41 1.8E-08 l.BE-03 3.2E-11215 S3 EI1FH 3 4 0 0 7.5E-06 TBVG2 9.9E-01 7.4E-04 l.OE-07 7.4E-13216 SS EMFH 3 4 0 0 7.5E-04 OVRF06 l.OE-02 21 7.5E-08 1.4E-04 l.lE-13217 SS EKFH T 4 0 0 7.5E-Q6 0VRFD7 3.4E-03 22 2.7E-03 l.OE-07 2.7E-1521B SS EMFH 3 n

L 0 1) 4.7E-04 TBVG3 9.9E-01 T 4.7E-04 l.OE-07 4.7E-13219 S.S EMFH T n 0 0 4.7E-04 TB'/G4 l.OE-02 4.7E-03 2.0E-03 9.4E-1L220 SS EMFH 4 1 0 0 8,4E-04 TBVG2 9.9E-01 •n

L 8.5E-04 l.OE-07 S.5E-13221 SS EMFH 4 1 0 0 8.6E-06 TBV6? l.OE-02 9 8.4E-03 2.0E-03 1.7E-10222 SS EMFH 5 I 0 0 6. 3E"'.‘6 TBV62 9.9E-01 6.2E-06 l.OE-07 4.2E-13223 SS EMFH 5 I 0 0 6.3E-06 T3VG9 l.OE-02 9 4.3E-08 2.0E-03 1.3E-10224 SS EMFH 6 I 0 0 7.0E-04 MSLB7 9.9E-01 •■iL 4.9E-06 4 .2E-04 4.3E-09225 S3 EMFH 4 1 0 0 7.0E-04 TEVG9 l.OE-02 9 7.0E-08 2.0E-03 1.4E-10226 RES EMFH 99 99 99 99 7.2E-05 DEF 1.OE+OO 99 7.2E-05 5.4E-03 3.9E-07227 SL LSLE I 0 0 9.6E-04 MSLBl 9.9E-01 24 9.5E-04 4.2E-04 5.9E-07228 SL LSLB 1 0 0 9,6E-04 TEVB9 l.OE-02 9 9.4E-06 2.0E-03 1.9E-08229 SL LSLB 1 1 V 0 3.0E-05 MSLB3 9.9E-01 28 3.0E-05 4.0E-04 1.2E-03230 SL LSLB 1 1 0 0 3.0E-05 TBV69 l.OE-02 9 3.0E-07 2.0E-03 4.0E-10231 SL LSLB T 0 0 0 5.5E-06 MSLBl 9.9E-01 26 5.4E-06 4.2E-04 3.4E-09232 SL LSLE 7 0 0 0 5.5E-04 TBVB9 l.OE-02 9 5.5E-08 2.0E-C3 l.lE-10233 RES LSLB 99 99 99 99 5.3E-04 DEF 1.OE+OO 99 5.3E-06 5.4E-03 2.9E-08234 SL SSLB 1 0 0 0 9.0E-03 TBVG2 9.9E-01 ■*k

L 8.9E-03 l.OE-07 S.9E-10235 SL SSLB 1 0 0 0 9.0E-03 TBvGl 1.0E-02 S

i 9.0E-05 4.CE-07 3.4E-11236 SL SSLE 1 1 0 0 2.8E-04 TBV62 9.9E-01 2 2.8E-04 l.OE-07 2.8E-11237 SL SSLB 1 I 0 0 2.8E-04 TBVGi l.OE-02 1

i 2.3E-04 4.0E-07 l.lE-12238 SS SSLB I 4 0 0 2.4E-06 TBVG2 9.9E-01 n

L 2.4E-06 l.OE-07 2.4E-13239 SS SSLB 1 4 0 0 2.4E-04 0VRFD6 l.OE-02 21 2.4E-03 1.4E-04 3.4E-14240 SS uSub 1 4 0 0 2.4E-04 0VRFD7 3.6E-03 8.6E-09 l.OE-07 8.4E-16241 SL SSLB 3 0 0 0 6.3E-04 TB'vSS 9.9E-01 8 4.2E-04 1.CE-07 4.2E-11242 SL SSLB 3 0 0 0 4.3E-04 TBVG5 l.OE-02 c

J 4.3E-04 5.2E-06 3.3E-11243 SL SSLB J 0 0 1 1.5E-05 TBVGB 9.9E-01 8 1.5E-C5 l.OE-07 1.5E-12244 SL SSLB 7 0 0 1 1.5E-05 TBVGIO l.OE-02 10 1.5E-07 l.OE-05 I.5E-12245 SL SSLB 7 0 0 7I. 4.0E-05 TBVG8 9.9E-01 3 4.0E-05 l.OE-07 4.0E-12246 SL SSLB 7 0 0 -*4

L 4.OE-05 TBVGIO 1.0E-02 10 4.0E-07 l.OE-05 4.CE-12247 SL SSLB 7

J 1 0 0 2.0E-05 TBVG8 9.9E-01 8 2.0E-05 l.OE-07 2.0E-12248 EL SSLB 7, I 0 0 2.0E-05 TBVG9 l.OE-02 n

7 2.0E-07 2.0E-03 4.0E-10249 SL SSLB 7 1 0 n

L l.OE-06 TBV6S 9.9E-01 e 9.9E-07 l.CE-07 9.9E-14250 SL SSLB 7 1 0 n l.OE-06 TBVSIO i.OE-02 10 l.OE-08 l.OE-05 1.0E-13251 SL SSLB 4 0 0 0 4.5E-04 TBVGI l.OE-02 1 4.5E-08 4.0E-07 2.4E-14252 SL SSLB 4 0 0 0 6.5E-04 TBVG2 9.9E-01 L 4.4E-04 l.OE-07 4.4E-13253 RES SSLB 99 99 99 99 1.4E-05 DEF 1.OE+OO 99 1.4E-05 5.4E-03 7.4E-03254 HuRft LOMFH 0 0 0 0 5.5E-01 NONE 1.OE+OO 0 5.5E-01 O.OE+OO 0.OE+OO255 LGCh LOMFH 0 0 0 1 1.4E-02 PSBGl 1.OE+OO 11 1.4E-02 l.OE-07 1.4E-09256 LOCA LOMFH 0 0 0 7L. 3.4E-02 PSBGi 1.OE+OO 11 3.6E-02 l.OE-07 3.4E-09257 F« LOMFH 0 7 0 0 2.0E-03 MIN 9.75E-01 98 2.0E-03 1.0E-07 2.0E-10258 FM LOMFH 0 7

■j 0 0 2.0E-03 INEL3 l.OE-02 53 2.0E-05 l.OE-07 2.0E-12259 FH LOMFH 0 ■j 0 I 5.1E-05 PSBGS 9.9E-01 15 5.0E-05 1.OE-07 5.0E-12260 FH LOMFH 0 ■J 0 1 5.1E-05 PSSG4 l.OE-02 14 5.1E-07 1.3E-03 4.4E-10261 FH LOMFH 0 3 0 2 1.3E-04 F'SBG5 9.9E-01 15 1.3E-04 l.OE-07 1.3E-11262 FH LOMFH 0 7 () 7L. 1.3E-04 PSBG4 l.OE-02 14 1.3E-06 1.3E-03 1.4E-09263 FH LOMFH 0 4 0 0 3.9E-03 NONE 9.9E701 0 3.9E-03 O.OE+OO O.OE+OO264 FH LOMFH 0 4 0 0 3.9E-03 0VRFQ6 l.OE-02 21 3.9E-05 1.4E-04 5.5E-11265 FH LOMFH 0 4 0 0 3.9E-03 0VRFD7 3.6E-03 L L 1.4E-05 l.OE-07 1.4E-12

A.35

REC TYPE INIT SPC FHS ECC PPC EFREQ TRANS HF TRANS# TFREQ P(FIT) P(THC)266 F« LOMFH 0 4 0 1 9.5E-05 NQNE 9.9E-01 0 9.4E-05 0 .OE+OO O.OE+OO267 F« LOMFH 0 4 0 1 9.5E-05 0VRFD6 l.OE-02 21 9.5E-07 l.4E-0i 1.3E-12268 FH LOMFH 0 4 0 1 9.5E-05 0VRFD7 3.6E-03 22 3.4E-07 1.0E-C7 3.4E-14269 FH LOMFH 0 4 0 T

L 2.5E-04 NONE 9.9E-01 0 2.5E-04 0.OE+OO O.OE+OO270 FH LOMFH 0 4 0 n

L 2.5E-04 0VRFD6 l.OE-02 21 2.5E-0i 1.4E-06 3.5E-L2271 FH LOMFH 0 4 0 9 2.5F-04 OVRFDT 3. iE"'.i3 22 9.0E~i)7 l.OE-OT 9.0E-14272 SL LOMFH 1 0 0 0 3.4E-02 TBVG2 9.9E-01 n

L 3.3E-02 l.OE-07 S.3E-09273 SL LOMFH t

iAV 0 0 8.4E-02 TEVGl 1. OE-02 1 8.4E-04 4.0E-07 3.4E-10

274 SL LOMFH 1 0 0 I 2 . lE-03 TBVG2 9.9E-01 nL 2.1E-03 l.OE-07 2.1E-10

275 BL LOMFH 1 0 0 I 2 . lE-03 TBVG6 l.OE-02 i 2.1E-05 1.7E-06 3 .i£ - l l276 SL LOMFH 1 0 0 n 5.5E-03 TEVG2 9.9E-01 9 5.4E-03 l.OE-07 5.4E-10277 BL LOMFH 1 0 0 L 5.5E-03 TBVG6 l.OE-02 t 5.5E-05 1.7E-0i 9.4E-11278 SL LOMFH 1 0 <i 0 l.lE-04 TBVG2 9.9E-01 2 l.lE-04 l.OE-07 l.lE-11279 SL LOMFH 1 0 1 I ) i.lE-04 TBv'Gl l.OE-02 1 l.lE-06 4.0E-07 4.4E-13280 SL LOMFH 1 0 1 1 2.7E-06 TBVG2 9.9E-01 n 2.7E-06 l.OE-OT 2.7E-13281 SL LOMFH 1 0 1 I 2.7E-06 TBV66 l.CE-02 6 2.7E-08 1.7E-06 4.iE-14282 SL LOMFH I c 1 n 6.2E-06 T3VG2 9.9E-01 9

s . i.lE-Oi l.OE-07 6.LE-13283 SL LOMFH 1 0 1 n

I 6.2E-06 TBVG6 l.OE-02 6 6.2E-08 1.7E-0i l.lE-13284 SS LOMFH 1 3 0 0 3.1E-04 TBV32 9.9E-01 9 3.1E-04 l.OE-07 3.1E-11285 SS LOMFH 1 3 0 0 3.1E-04 LANL7 l.OE-02 41 3.1E-04 l.BE-03 J . 6E-09286 SS LOMFH 1 j 0 1 7.0E-06 P3S55 9.9E-01 15 6.9E-06 l.OE-07 4.9E-13287 SS LOMFH 1 ■J 0 1 7.0E-06 TBVGi l.OE-02 i 7.0E-03 1.7E-0i 1.2E-13238 SS LOMFH 1 T 0 9 1.6E-05 P3BS5 9.9E-01 15 1.6E-05 l.OE-07 l.iE-12289 SS LOMFH 1 ■J 0 9 1.6E-05 TBVGi l.OE-02 i l.iE-07 1.7E-0i 2.7E-13290 S3 LOMFH 1 4 0 0 5.9E-04 TBVG2 9.9E-0i I 5.3E-04 l.OE-OT 5.SE-11291 SS LOMFH 1 4 0 0 5.9E-04 OVRFDi l.OE-02 9 4

L 1 J.9E-06 1.4E-0i 8.3E-12292 SS LOMFH I 4 0 0 5.9E-04 OVRFDT 3.6E-03 n n

i . L 2.1E-06 l.OE-07 2.1E-13293 cc

■J\J LOMFH I 4 0 1 I. 5E-05 PSBGS 9.9E-01 15 1.5E-05 1.OE-07 1.5E-12294 SS LOMFH 1 4 0 i 1.5E-05 QVRFD6 l.OE-02 21 1.5E-07 1.4E-06 2.1E-13295 SS LOMFH 1 4 0 1 1.5E-05 OVRFDT 3.tE-03 22 5.4E-08 l.OE-07 5.4E-15296 SS LOMFH 1 4 fl 1 3.7E-05 PSEG5 9,9E-01 15 3.7E-05 l.OE-07 3.7E-12297 SS LOMFH 1 4 0 n

L 3.7E-05 OVRFDi l.OE-02 21 3.7E-07 1.4E-06 5.2E-13298 SS LOMFH 1 4 0 n

t . 3.7E-05 OVRFDT 3.6E-03 22 1.3E-07 l.OE-07 1.3E-14299 SL LOMFH '■ 0 0 ■') 9.BE-04 TBVG2 9.9E-01 0 9.7E-04 0.OE+OO O.OE+OO300 SL LOMFH n 0 0 0 9.8E-04 TBVGI l.OE-02 0 9.8E-06 O.OE+OO O.OE+OO301 SL LOMFH 9 0 1 2.4E-03 PSEG5 9.9E-01 1 - 2.4E-05 l.OE-07 2.4E-12302 SL LOMFH n

L 0 '■} I 2.4E-05 TBVGi l.OE-02 6 2.4E-D7 1.7E-06 4.1E-13303 SL LOMFH I A 9 6.3E-05 PSBGS 9.9E-0! 15 6.2E-05 l.OE-07 6.2E-12304 SL LOMFH n 0 0 0 4.3E*iJ5 TBVGi l.OE-02 6 6.3E-07 1.7E-06 l.iE-12305 SS LOMFH 2 ' j 0 0 3.0E-06 TBVG2 9.9E-01 n

L 3.0E-06 l.OE-07 3.0E-13306 SS LOMFH • j 0 3.0E-06 LANL7 l.OE-02 41 3.0E-03 1.8E-03 5.4E-11307 SS LOMFH 9 4 0 5.0E-06 TBVG2 9.9E-01 2 5.0E-06 1.OE-07 5.0E-13308 SS LOMFH 2 4 0 j.OE-06 OVRFDi l.OE-02 21 5.0E-08 1.4E-06 7.0E-14309 SS LOMFH 2 4 0 5.0E-06 OVRFDT 3.iE-03 22 1.8E-06 l.OE-07 1.8E-15310 SL LOMFH 3 0 (3 0 9.2E-03 TBVGB 9.9E-01 3 9.1E-03 i.OE-07 9.1E-10311 SL LOMFH 7 0 0 0 9.2E-03 T B v e s l.OE-02 5 9.2E-05 5,2E-0i 4.SE-10312 SL LOMFH 3 0 0 »1. 2.3E-04 TBVG8 9.9E-01 8 2.3E-04 l.OE-07 2.3E-11313 SL LOMFH 3 0 0 1 2.3E-04 TBVGIO I.OE-02 10 2.3E-0i l.OE-05 2.3E-11314 SL LOMFH 7 0 0 9

L. 6.0E-C4 TBVG8 9.9E-01 a 5.9E-04 1.OE-07 5.9E-11315 SL LOMFH 7 0 0 ■n

i . 6.0E-04 TBVGIO 1.OE-02 10 i.OE-06 l.OE-05 i.OE-11316 SL LOMFH 7

•J 0 1 (I 1.2E-05 TBVGB 9.9E-01 8 1.2E-C5 l.OE-07 ' .2E-12317 SL LOMFH 1 0 1 0 1.2E-05 TBVG5 l.OE-02 5 1.2E-07 5.2E-04 4.2E-I3318 SS LOMFH 7

V 3 0 0 3.4E-05 TBVG2 9.9E-01 n 3.4E-C5 1.OE-07 3.4E-12

A . 3 6

REC TYPE INIT SPC FHS ECC PPC EFRES TRANS HF TRAHS# TFREQ PIFITI PITHC)319 S3 LOttFH 7

■J -J 0 0 3.4E-05 LANL7 l.OE-02 41 3.4E-07 1.8E-03 6.1E-10320 SS LOMFH 3 3 0 2 1.8E-06 PSB65 9.9E-01 15 1.8E-06 l.OE-07 l.OE-13321 S3 LOMFH 3 3 0 2 l.SE-06 TBVQ6 l.OE-02 6 1.3E-03 1.7E-06 3.1E-14322 SS LOMFH 3 4 0 0 6.5E-05 TBVB2 9.9E-01 L 6.4E-05 l.OE-07 6.4E-12323 SS LOMFH T 4 0 0 6.5E-05 QVRF06 l.OE-02 21 6.5E-C7 1.4E-06 9.1E-13324 SS LOMFH y

0 4 0 0 6.5E-05 QVRFD7 3.6E-03 2.3E-07 l.OE-07 2.3E-14325 SS LOMFH t; 4 0 1 1.3E-06 PSBGS 9.9E-01 15 1.3E-06 l.OE-07 U3E-13326 S3 LOMFH 3 4 0 1 1.3E-06 QVRFD6 1.0E-U2 21 1.3E-08 1.4E-06 t.8E-14327 SS LOMFH 7

•J 4 0 1 1.3E-06 0VRFD7 3.6E-03 22 4.7E-09 l.OE-07 4.7E-16328 SS LOMFH 7 4 0 nL 3.0E-06 PSBG5 9.9E-01 15 3.0E-06 l.OE-07 3.0E-13329 SS LOMFH 4 0 ')

J . 3.0E-06 0VRF06 l.OE-02 21 3.0E-09 1.4E-C6 4.2E-14330 SS LOMFH 3 4 0 3.0E-06 0VRFD7 3.6E-03 nnLL l.lE-08 l.OE'07 l.lE-15331 SL LOMFH 4 0 0 0 8.3E-05 TBVG2 9.9E-01 2 3.2E-05 l.OE-07 3.2E-12332 SL LOMFH 4 0 0 (I 8.3E-05 TBVGI l.OE-02 1 S.3E-07 4.0E'07 3.3E-13333 SL LOMFH 4 0 0 nL 4.3E-06 TSVG2 9.9E-01 2 4.3E-04 l.OE-07 4.3E-13334 SL LOMFH 4 0 0 4.3E-06 TBVSIO l.OE-02 10 4.3E-0S l.OE-05 4.3E-13335 SL LOMFH 5 0 0 0 5.4E-05 TBV32 9.9E-01 TL 5.3E-05 i.OE-07 5.3E-12336 SL LOMFH r

J 0 0 0 5.4E-05 TBVG5 1.OE-02 CJ 5.4E-07 5 ,ZE'Oi 3.8E-12

337 SL LOMFH 5 0 0 1 1.3E-06 TBVG2 9.9E-01 nL 1.3E-06 l.OE-07 1.3E-13338 SL LOMFH 5 0 0 1i 1.3E-06 TBVGIO 1.0E-02 10 1.3E-03 l.OE-05 1.3E-13339 SL LOMFH c 0 0 nL 3.1E-06 TBVG2 9.9E-01 2 3 . lE-06 1.0E'07 3.1E-13340 SL LOMFH rJ 0 0 n 3.1E-06 TBVGIO l.OE-02 10 3 . lE-08 l.Ot'Oj 3 .IE-13341 SL LOMFH 6 0 0 6.1E-05 MSLBl 9.9E-01 26 6.0E-05 6.2E-04 3.7E-u3342 LOMFH 6 0 0 0 6.1E-05 MSLBl 9.9E-01 26 6.0E-05 6.2E-04 3.7E-0B343 LOMFH 6 0 0 0 6.1E-05 TBVS9 l.OE-02 9 6.1E-07 2.0E-03 1.2E-09344 BL LOMFH 6 Q 0 1 1.5E-06 MSLB7 9.9E-01 32 1.5E-04 6,2E"04 9.2E-10345 SL LOMFH 6 0 0 I 1.5E-06 TBVG9 l.OE-02 9 1.5E-0B LtOE'Oj 3.GE-11346 SL LOMFH 6 0 0 ■T

i . 3-;5E-06 MSlB7 9.9E-01 32 3.5E-06 6.2E-04 2.1E-C9347 SL LOMFH 6 0 0 3.5E-06 T6VG9 l.OE-02 9 3.5E-08 2.0E-03 7.0E-U348 RES LQMFM 99 99 99 99 5.9E-05 OEF 1.OE+OO 99 5.9E-05 5.4E-03 3.2E-07349 LQCA SBLt 0 0 0 0 7.6E-02 PSBGl 1.OE+OO 11 7.6E-02 l.OE-07 7.6E-09350 LOCA SBLl 0 0 0 1 1.9E-03 PSBGl 1.OE+OO 11 1.9E-03 l.OE-07 1.9E-10351 LQCA SBLl 0 0 0 i. 5.0E-03 PSBGl 1.OE+OO 11 5.0E-03 l.OE-07 5.0E-10352 LOCA SBLl 0 0 1 0 9.9E-05 PSBGl 1.OE+OO 11 9.9E-05 I.OE-07 9.9E-12353 LOCA SBLl 0 0 1 I 2.4E-06 PSBGl 1.OE+OO 11 2.4E-06 l.OE-07 2.4E-13354 LOCA SBLl 0 0 1 n 5.5E-06 PSBGl i.OE+OO 11 5.5F-06 l.OE-07 5.5E-13355 LOCA SBLl U 1 0 2.4E-03 PSBGl 1.OE+OO 11 2.4E-03 1.OE-07 2.4E-I0356 LOCA SBLl 0 1 1 5.9E-05 PSBGl 1.OE+OO 11 5.9E-05 1.0E-07 5.9E-12357 LOCA SBLl 0 1 0 9 1.6E-04 PSBG5 1,OE+OO 15 1.6E-04 l.OE-07 1.6E-11358 LOCA SBLl A 1 1 0 2.5E-06 PSBGS 1.OE+OO 15 2.5E-06 l.OE-07 2.5E-13359 LOCA SBLl 0 3 0 0 6.6E-06 PSBGS 9.9E-01 15 4.5E-06 l.OE-07 6.5E-13360 LOCA SBLl 0 0 0 6.6E-06 PSBG4 l.OE-02 14 6.6E-08 1.3E-03 e.3E-ll361 LQCA SBLl 0 4 0 0 3:lE-05 NQNE 9.9E-01 0 3.1E-05 O.OE+OO O.OE+OO362 LQCA SBLl 0 4 0 0 3.1E-05 OVRFDi l.OE-02 21 3.1E-07 1.4E-04 4.3E-13363 LOCA SBLl 0 4 0 3.1E-05 QVRF&7 3.6E-03 •TOLL. l.lE-07 l.OE-07 l.lE-14364 LOCA SBLl 0 0

i . 0 0 B.7E-06 TBVG2 9.9E-01 nL B.6E-06 1.OE-07 8,6E-13365 LOCA SBLl 0 nL 0 c 3.7E-06 TBVG6 l.OE-02 6 3.7E-03 1.7E-06 1.5E-13366 LOCA SBLl i

I 0 0 0 1.2E-02 TBVG2 9.9E-01 nL 1.2E-02 l.CE-07 l,2E-09367 LOCA SBLl 1 0 0 0 1.2E-02 TBVGi l.OE-02 6 1.2E-04 1.7E-0i 2.0E-10363 LOCA SBLl \i 0 0 I 2.9E-04 r» #“■ Cl n «

r a b a - j 9.9E-01 15 2.9E-04 l.OE-07 2.9E-!I369 LQCA SBLl 1 0 0 [ 2.9E-04 TFVG6 l.OE-02 6 2.9E-06 1.7E-06 4.9E-12370 LQCA 3BL1 1 0 0 £ 7;5E-i)4 PS3S‘> 9.9E-01 15 7.4E-04 l.OE-07 7.4E-11371 LQCA SBLl 1 0 0 n

i . 7.5E-04 TBVGi 1.0E-02 6 7.5E-06 1.7E-0t 1.3E-H

A.37

REC TYPE INIT SPC FNS ECC PPC EFREQ TRANS- HF TRANS* TFREQ PlFlTl Pi.INCl372 LGCA SBLl I 0 1 0 1.3E-C5 T3VG2 V.9E-01 2 1.3E-05 1.0E-C7 1.3E-12373 LOCA SBLl 1 0 1 0 1.3E-05 TBVS6 I.OE-02 6 1.3E-07 1.7E-06 2.2E-13374 LQCA SBLl 1 7

■J 0 0 1.7E-05 PS3G5 9.9E-01 15 1.7E-05 l.OE-07 1.7E-12375 LOCA SBLl 1 rj 0 0 117E"Cd TBVG6 l.OE-02 6 1.7E-07 1.7E-06 2.9E-13376 LOCA SBLl I 4 0 0 7.7E-05 PSBG5 9.9E-01 15 7 .SE-05 l.OE-07 7.6E-12377 LOCA SBLl 1 4 0 0 7.7E-05 QVRFD6 l.OE-02 21 7.7E-07 1.4E-06 l.lE-12378 LOCA SBLl 1 4 0 •7

L 3.6E-06 P3065 9.9E-01 15 3.6E-0S l.OE-07 3.4E-13379 LOCA SBLl 1 4 0 i 3.6E-06 QVRFD6 l.CE-02 21 3.6E-08 U4E-06 5.CE-14380 LQCA SSL! 1 4 0 2 3.6E-06 QVRF117 3.6E-03 22 1.3E-03 l.OE-07 1.3E-15381 LOCA SBLl 1 I 0 0 3.7E-04 PSBG5 9.9E-01 15 3.7E-04 l.OE-07 3.7E-11382 LOCA SBLl 1 1 0 0 3.7E-04 TBVG6 l.OE-02 6 3.7E-06 1.7E-06 6.3E-12383 LGCA SBLl 1 1 0 1 8.2E-06 PSBG5 9.9E-01 15 3.1E-C6 l.OE-07 B.lE-13384 LOCA SBLl 1 1 0 I 8.2E-06 TBVG6 l.OE-02 6 3.2E-08 1.7E-06 1.4E-13385 LOCA SELl 1 1 0 2 2.1E-05 FSBG5 9.9E-01 15 2.1E-05 l.OE-07 2.1E-12386 LOCA SBLl 1 1 0 2 2.1E-05 TEV66 l.OE-02 6 2.1E-07 1.7E-06 3.6E-13387 LOCA SBLl L 0 0 0 1.4E-04 P3BQ5 9.9E-01 15 1.4E-C4 l.OE-07 1.4E-11388 LOCA SBLl *

i . 0 0 1.4E-04 TBVG6 l.OE-02 6 1.4E-06 1.7E-06 2.4E-12389 LOCA SBLl L 0 2 7.6E-06 P3BG5 9.9E-0T 15 7.5E-06 l.OE-07 7.5E-13390 LOCA SBLl nt. 0 0 2 7.dE-06 TBVG6 l.OE-02 6 7.4E-0a 1.7E-06 1.3E-13391 LOCA SBLl 2 1 0 0 3.5E-06 78963 9.9E-01 3 3.5E-06 i.OE-07 3.5E-13392 LOCA SBLl 2 1 0 0 3.5E-06 TBVG4 l.OE-02 4 3.5E-08 2.0E-03 7.0E-11393 LOCA SBLl 3 0 0 0 1.3E-03 TBVG8 9.9E-01 8 1.3E-03 l.OE-07 1.3E-10394 LOCA SBLl 7 ’ 0 0 0 1.3E-C3 TBVGIO l.CE-02 10 1.3E-05 l.OE-05 1.3E-10395 LQCA SBLl 7J 0 0 1 3.0E-05 T8VG3 9.9E-01 8 3.0E-05 l.OE-07 3.0E-12396 LQCA SBLl 3 0 0 I 3.0E-05 TBVGIO l.OE-02 10 3.0E-0; l.OE-05 3.0E-12397 LOCA S3L1 7

■J 0 0 L 8.3E-05 TSVG8 9.9E-01 e 3.2E-05 l.OE-07 8.2E-12398 LOCA SELl 3 0 0 2 8.3E-05 TBVGIO l.OE-02 10 S.3E-07 l.OE-05 8.3E-12399 LOCA SBLl 7 0 1 0 1.4E-06 TBV68 9.9E-01 8 1.4E-06 l.OE-07 1.4E-13400 LOCA SBLt j 0 1 0 1.4E-06 TBVGIO l.OE-02 10 i.4E-03 l.OE-05 1.4E-13401 LOCA SBLl 7 3 0 0 1.9E-06 TBVG2 9.9E-01 n

L 1.9E-06 1.0E-C7 1.9E-13402 LOCA SsLl 7

•J 3 0 0 1.9E-04 LANL7 l.OE-02 41 1.9E-03 1.8E-03 3.4E-11403 LOCA SBLl 7 4 0 0 7.8E-06 TBV62 9.9E-01 -n

L 7.7E-06 1.0E-C7 7.7E-13404 LQCA SBLl 7■J 4 0 0 7,8E-06 0VRFD6 l.OE-02 21 7.BE-08 1.4E-06 l.lE-13405 LOCA SELl 7 4 0 0 7.BE-06 0VSFD7 3.6E-03 22 2.3E-C8 l.OE-07 2.8E-15406 LOCA SELl 3 1 0 0 4.0E-05 TBVG3 9.9E-01 8 4.0E-05 l.OE-07 4.0E-12407 LQCA SBLl 3 1 0 0 4.0E-05 TBVGIO l.OE-02 10 4.0E-07 1.0E-C5 4.0E-12403 LCCA SELl 7■J 1 0 2 2.1E-06 TBVGB 9.9E-01 3 2.1E-04 l.OE-07 2.1E-13409 LOCA SBLl 7 I 0 n

i . 2. lE-Ofc TBVGIO l.OE-02 10 2.1E-08 l.OE-05 2.1E-I3410 LOCA SBLl 4 0 0 0 ?.lE-Oi TBVGB 9.9E-01 2 9.0E-06 l.OE-07 9.0E-13411 LQCA SBLl 4 0 0 0 9.(£-06 TBVGIO l.OE-02 10 9.1E-08 l.OE-05 9.1E-13412 LQCA SBLl 5 0 0 0 4.6E-06 TBVGB 9.9E-01 2 6.5E-06 l.OE-07 6.5E-13413 LOCA SBLl 5 0 I) 0 6.6E-06 TBVGIO l.OE-02 10 6.6E-08 i.OE-05 6.6E-13414 LOCA SELl 6 0 0 0 7.3E-04 NSLB7 9.9E-01 32 7.2E-06 6.2E-C4 4.5E-09415 LOCA SSLl 6 0 0 0 7.3E-06 TBVE? l.OE-02 9 7.3E-08 2.0E-03 1.5E-10416 RES SBLl 99 99 99 9? 7.BE-05 DEF 1.OE+OO 99 7.8E-05 5.4E-03 4.2E-07417 LQCA SEL2 0 0 0 0 S.2E-03 PSBGl 1.OE+OO 11 8.2E-03 l.OE-07 8.2E-10418 LQCA SBL2 0 0 1 0 l.OE-05 PSBGl 1.OE+OO 11 l.OE-05 l.OE-07 l.OE-12419 LOCA SBL2 0 I 0 0 2.6E-04 PSBGS 9.9E-01 15 2.6E-04 l.OE-07 2.6E-11420 LQCA SEL2 0 1 e 0 2.6E-04 P38G4 l.OE-02 14 2.6E-06 1.3E-03 3.3E-C9421 LOCA SBL2 0 4 0 0 2.7E-0& NQNE 9.9E-C1 0 2.7E-0i O.OE+OO 0.OE+OO422 LOCA SBL2 0 4 0 0 2.7E-0S 0VRFQ4 l.OE-02 21 2.7E-03 1.4E-06 3.3E-14423 LOCA SBL2 0 4 0 0 2.7E-06 0VRF07 3.6E-03 22 9.7E-09 1.0E-C7 9.7E-14424 LOCA SBL2 0 n

i . 0 0 l.OE-06 DEF

A . 38

1.OE+OO 99 l.OE-06 5.4E-03 5.4E-09

REC TYPE INIT SPC FHS ECC PRC EFREQ TRANS HF TRANSI TFREQ PIFITI P(THC)425 LOCft SBL2 1 0 0 0 1.2E-03 TBVS2 9.9E-01 2 1.2E-03 l.OE-07 1.2E-10424 LQCA SBL2 1 0 0 0 1.2E-03 TSVG4 l.OE-02 4 1.2E-05 1.7E-04 2.0E-11427 LQCA SBL2 1 3 0 0 2.1E-04 PSB65 9.9E-01 15 2. lE-04 1.0E-07 2.1E-13428 LOCA SBL2 1 3 0 0 2.1E-04 TBVG4 l.OE-02 4 2.1E-08 1.7E-04 3.6E-14429 LQCA SBL2 I 4 0 0 4.9E-04 F3BG5 9.9E-01 15 4.BE-04 l.OE-07 4.SE-13430 LGCA SBL2 1 4 0 0 4.9E-04 QVRFG4 l.OE-02 21 4.9E-C3 1.4E-04 9.7E-14431 LQCA SBL2 1 4 0 0 4.9E-04 QVRF37 3.4E-03 L L 2.5E-0S l.OE-07 2.5E-15432 LQCA 3BL2 1 1 0 0 4.0E-05 RSBG5 9.9E-01 15 4.0E-05 l.OE-07 4.0E-12433 LOCA SBL2 1 1 0 0 4.0E-03 TBVG4 l.OE-02 4 4.0E-07 1.7E-04 4.BE-i3434 LQCA SBL2 0 0 1.4E-05 P5BG5 9.9E-01 15 1.4E-05 l.OE-07 1.4E-12435 LOCA S8L2 0 0 0 1.4E-05 TEVG6 l.OE-02 4 1.4E-07 1.7E-04 2.4E-13434 LQCA SEL2 T 0 (l- 1.4E-04 TB0S6 9.9E-01 8 1.4E-04 l.OE-07 1.4E-11437 LQCA SBL2 T 0 0 1.4E-04 TBVGIO l.OE-02 10 1.4E-04 l.OE-05 I.4E-11438 LQCA EBL2 7 0 0 4.0E-04 TEVSB 9.9E-01 3 4.0E-04 l.OE-07 4.0E-I3439 LOCA SBL2 1 0 0 4.0E-04 TBVGIO l.CE-02 10 4.0E-08 l.OE-05 l.OE-13440 RES SBL2 99 99 99 99 1.SE-05 BEF i.Ot+00 99 1.8E-05 5.4E-03 9.9E-0S441 SSTR SSTR 0 0 0 S.2E-03 SGTR 1.OE+OO 23 S.2E-03 l.OE-07 8.2E-10442 SGTR SGTR 0 1 0 l.OE-05 SGTR I.OE+OO 23 l.OE-05 l.OE-07 l.CE-12443 SGTR SGTR 0 1 0 0 2.4E-04 P3EG5 9.9E-01 15 2.4E-04 l.OE-07 2.4E-1I444 SSTR SSTR 0 I 0 0 2.4E-04 PSBG4 l.OE-02 14 2.4E-04 1.3E-03 3.3E-09445 SSTR SGTR 0 4 0 0 2.7E-06 NONE 9.7E-01 0 2.7E-04 O.OE+OO O.OE+OO444 SSTR SGTR 0 4 0 0 2.7E-06 Ov'RFCG l.OE-02 21 2JE-08 1.4E-04 3.BE-14447 SSTR SSTR 0 4 0 0 2.7E-(f4 QVRFD7 3.4E-03 22 9.7E-09 1.0E-07 9.7E-14443 SSTR SGTR ;) 0 hOE-06 TBVG2 9.9E-0i n

L 9.9E-07 l.OE-07 9.9E-14449 SGTR SSTR 0 0 0 l.OE-06 TBVG4 l.OE-02 4 l.OE-OS 1.7E-04 1.7E-14150 SGTR SGTR 1 0 0 1.2E-03 TBVe2 9.9E-01 L 1.2E-03 l.OE-07 1.2E-10451 SGTR SSTR 1 0 0 1.2E-03 TB0G4 l.OE-02 4 I.2E-C5 1.7E-04 2.0E-1I452 SGTR SGTR 1 0 0 2.1E-0fc P3BG5 9.9E-0! 15 2.1E-04 l.OE-07 2.1E-13453 SGTR SGTR 1 3 0 0 2 . IE-04 TBVG6 l.OE-02 4 2.1E-08 1.7E-04 3.4E-14454 SGTR SSTR 1 4 0 0 4.9E-04 PSES5 9.9E-01 15 4.SE-C4 l.OE-07 4.SE-13455 SGTR SGTR 1 4 0 0 4.9E-04 QVRFD4 r.OE-02 21 4.9E-03 1.4E-04 9.7E-14454 SG'R SSTR 1 4 0 0 6.9E-06 QVRFD7 3.4E-03 22 2.5E-08 l.OE-07 2.5E-15457 SGTR SGTR I 1 0 0 4.0E-05 PSBG5 9.9E-01 15 4.0E-05 i.OE-07 4.0E-12458 SGTR SGTR i 1 0 0 4.0E-05 TBVG4 l.OE-02 4 4.0E-07 1.7E-04 4.8E-13459 SGTR SSTR n

i. 0 0 0 l.lE-05 P3SG5 9.9E-0! 15 t.4E-05 l.OE-07 1.4E-12440 SGTR SGTR 0 0 0 1.4E-05 TBV64 l.OE-02 4 1.4E-07 1.7E-C4 2.4E-13441 SGTR iSTR ? 0 0 0 1.4E-04 Tsves 9.9E-01 a 1.4E-04 l.OE-07 1.4E-11442 SSTR SoTR T 0 0 0 1.4E-04 TBVGIO l.OE-02 10 1.4E-04 l.OE-05 1.4E-11443 SG R SG'R T L 0 0 4.0E-04 TBVGB 9.9E-01 s 4.0E-04 l.OE-07 4.0E-13444 SGTR SGTR 7 1 0 f! 4.0E-0& TBVSIO l.OE-02 10 4.0E-06 l.OE-05 i.CE-13445 RES SGTR 9? 99 99 99 I.SE-05 DEF 1.OE+OO 99 l.BE-05 5.4E-03 9.9E-08444-NORN SI 0 0 0 0 7.4E-03 NONE i.CE+00 0 7.4E-03 O.OE+OO O.OE+OO447 LQCA SI 0 0 0 I 1.9E-H PSBGl 1.OE+OO 11 1.9E-04 1.0E-07 1.9E-11448 LOCA SI 0 0 0 i . 5.0E-04 PSBGl ! . OE+OO 11 5.CE-04 l.OE-07 5.0E-11449 FH SI 0 1 0 0 2.4E-04 QVRFB3 1.OE+OO 18 2.4E-04 l.OE-07 2.4E-11470 LGC.A SI 0 1. 0 1 5.4E-04 TEVG2 9.9E-01 2 5..3E-C4 l.OE-07 5.3E-13471 LQCA SI 0 1 0 I 5.4E-04 TBVG4 t.OE-02 4 5.4E-08 1.7E-04 9.2E-14472 LOCA SI 0 I 0 ■1

u 1.5E-05 TBVG2 9.9E-01 2 1.5E-05 l.OE-07 1.5E-12473 LQCA SI 0 1 0 r-i. 1.5E-05 TBVG6 l.OE-02 4 1.5E-07 1.7E-04 2.4E-13474 FH SI I) 4 0 0 2.2E-C6 NONE 9.9E-0i 0 2.2E-04 O.OE+OO 0:OE+OO475 FH SI 0 4 0 0 2.2E-04 QVRFD4 i.OE-02 21 2.2E-08 1.4E-04 3.1E-14474 FH SI (i 4 (1 0 2.2E-06 OVRFDT 3.4E-03 22 7.9E-09 l.CE-07 7.9E-14477 SL 51 1 0 0 0 1.2E-03 TBV82 9.9E-01 2 1.2E-C3 i.OE-07 1.2E-10

A. 39

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TRANS4 TFREQ P(FIT) P(TWC)478 SL SI 1 0 0 0 1.2E-03 TBVGI l.OE-02 1

i 1.2E-05 4.0E-07 4.3E-12479 SL SI 1 0 0 1 2.BE-05 T3VG2 9.9E-01 2 2.6E-05 l.CE-07 2 . e £ - 1 2

4 80C} 31 1 0 0 1 2.3E-05 TBvG6 1.0E-02 6 2.8E-07 1.7E-06 4.3E-13

481 SL SI 1 0 0 ni . 7.2E-05 TBVG2 9.9E-01 2 7.1E-05 l.OE-07 7.1E-12

482 SL 31 1 0 0 0 7.2E-C5 TEVG6 l.OE-02 6 7.2E-07 1.7E-06 1.2E-12483 ES SI f

1 4 0 1) 5.7E-06 T3VS2 9.9E-01 i 5.6E-06 l.OE-07 5.4E-13484 S3 SI I 4 0 0 5.7E-06 QVRFD6 l.OE-02 21 5.7E-03 1.4E-06 3.0E-14485 S3 CT

J L 1 4 1) 0 5.7E-06 0VRFD7 3 ,6E-03 •nn 2.1E-08 l.DE-07 2.1E-15486 SS 51 1 1 0 0 3.6E-05 T3VG2 9.9E-01 2 3.6E-C5 l.OE-07 3.6E-12487 SS SI 1

X 1 0 0 3.6E'i35 'BVGl l.CE-02 1 3.6E-07 4.0E-07 1.4E-13488 SL SI n 0 0 0 1.2E-05 T3VG2 9.9E-01 2 1.2E-C5 l.OE-07 1.2E-12489 SL SI 2 0 0 0 1.2E-05 TBVGI l.OE-02 1 1.2E-C7 l.OE-07 4.0E-14490 SL SI T 0 0 0 1.3E-04 TBVGB 9.9E-01 8 1.3E-04 l.OE-07 1.3E-11491 SL SI 7 0 0 0 1.3E-04 TEVG5 l.OE-02 -J 1.3E-C6 5.2E-06 6.8E-12492 SL SI 3 0 0 I 3 . lE-06 TBV68 9.9E-01 8 3.1E-06 l.OE-07 3.1E-I3493 EL SI 7 0 c

♦i 3.1E-06 TBVGIO l.OE-02 10 3.1E-C8 1.0E-C5 3 . lE-13

494 SL SI t; 0 e A 7.1E-04 TBVGS 9.9E-C1 8 7.0E-06 l.OE-07 7.0E-13495 SL SI T 0 0 n

L 7.1E-06 TBVSIO 1.0E-C2 10 7.1E-08 l.OE-05 7.1E-13496 S3 SI 3 1 0 0 3.3E-06 TBVG3 9.9E-01 8 3.3E-06 l.OE-07 3.3E-13497 SS SI 7 1 0 0 3.3E-06 TBVGS l.OE-02 9 3.3E-08 2.0E-03 4.6E-11498 RES SI 99 99 99 99 3.9E-05 DEF 1.OE+OO 99 3.9E-05 5.4E-03 2.1E-07

A.40

APPENDIX B

EVENT TKEE QUANTIFICATION

B . l I n t r o d u c t io n

T his appendix p r e s e n t s th e i n i t i a l p r o b a b i l i t y in fo rm a t io n used in the

Oconee PIS s tu d y . While n o t a l l of th e in fo rm a tio n in t h i s appendix was

used in th e s tu d y , i t i s in c lu d e d f o r com ple teness .

To d e te rm in e bounding v a lu e s f o r sequence f r e q u e n c ie s , b ranch p r o b a b i l i t i e s

were e s t im a te d f o r each b ran ch on th e ev en t t r e e s . I t must be emphasized

t h a t imposed c o n s t r a i n t s p e r m i t t e d o n ly s im p l i f i e d approaches to f requency

and p r o b a b i l i t y e s t im a t io n , in c lu d in g , in s e v e ra l c a s e s , th e use o f g e n e r ic

d a t a . As w ith a l l even t t r e e s , th e p r o b a b i l i t y of b e ing on a p a r t i c u l a r

b ran ch i s c o n d i t io n a l on th e p r i o r b ran ch e s in th e sequence. In most

c a s e s , however, b ran ch e s were s u f f i c i e n t l y independent to pe rm it th e use

of common p r o b a b i l i t y v a lu e s in th e sequence q u a n t i f i c a t i o n s .

P r o b a b i l i t y v a lu e s were e s t im a te d , when p o s s i b l e , from o p e r a t io n a l

in fo rm a t io n which was as c lo s e t o O c o n e e -s p e c i f ic as p o s s i b l e . I f Oconee-

s p e c i f i c in fo rm a t io n was a v a i l a b l e , th e n i t was u sed . I f t h i s was no t

th e c a s e , B&W-specific and f i n a l l y PW R-specifled o p e r a t io n a l in fo rm a tio n

was employed. A d d i t io n a l in fo rm a t io n was o b ta in e d from sc re e n in g v a lu e s

from "IEEE Guide to th e C o l l e c t io n and P r e s e n t a t i o n o f E l e c t r i c a l ,

E l e c t r o n i c , and Sensing Component R e l i a b i l i t y Data fo r N uclear-Pow er

G en e ra t in g S t a t i o n , " IEEE S td 500-1977, sponsored by th e N uclear Power

E n g in ee r in g Committee o f th e IEEE Power E ng ineer ing S o c ie ty , as w e l l as

o th e r s o u rc e s .

B . l

S e c t io n B.2 p ro v id e s development in fo rm a t io n and f i n a l p r o b a b i l i t y and

f req u en cy v a lu e s f o r s y s t e m - r e l a t e d f a i l u r e s in c lu d e d in tb e even t t r e e s .

A p p lic a b le so u rces o f f a i l u r e in fo rm a t io n a re i d e n t i f i e d . S e c t io n B.3

d e s c r ib e s th e human r e l i a b i l i t y numbers employed on th e t r e e s . P r o b a b i l i t y

v a lu e s s t r o n g ly iaq>acted by th e rm a l -h y d ra u l ic c o n s id e r a t io n s a re d is c u s s e d

in S e c t io n B .4 .

B.2 S ys tem -R e la ted P ro b a b i l i tY _ V a lu e s

The b a s e s f o r th e s y s t e m - r e l a t e d p r o b a b i l i t y v a lu es used on th e even t t r e e

b ran ch e s a re p ro v id e d in T ab le B . l .

B.3 Human E r r o r - R e la te d P r o b a b i l i t v Values

Branch p r o b a b i l i t y v a lu e s dom inated by human perform ance were developed

b ased on th e "Handbook o f Human R e l i a b i l i t y A n a ly s is " (NDRE6/CR-127S), th e

"G eneric D ata Base f o r Data and Models C hap ter of th e NREP Guide" (EGG-

EA-5887, June 1982 ) , p a s t B&V p l a n t o p e r a t io n a l e x p e r ie n c e w ith steam

g e n e r a to r o v e r f i l l ("AEOD O b se rv a t io n s and Recommendations Concerning the

Problem o f Steam G en e ra to r O v e r f i l l and Combined P rim ary and Secondary Side

Blowdown," December 17 , 1 9 8 0 ) , as w e l l as re q u ire m e n ts f o r o p e r a to r a c t io n

as d e s c r ib e d in a p p l i c a b l e Oconee p ro c e d u re s .

I n g e n e r a l , b ran ch p r o b a b i l i t i e s u t i l i z e d on even t t r e e b ran ch e s dominated

by human e r r o r were c o n s i s t e n t w ith NUREG/CR-1278. Human e r r o r v a lu e s used

w ere:

a . For w e l l d e f in e d ta s k s under l i t t l e p r e s s u r e t h a t r e q u i r e d s p e c i f i c_3

a c t i o n , 5 z 10 /D was a s s ig n e d . T h is v a lu e was employed, f o r

B.2

Table B .l S y e tea -R e la ted Event Tree F reqnenoies And B ranch P r o b a b i l l t i e a

Fnnction Diacnaaion Valne Baed

I n i t i a t o r s

R eac to r T rip

Small Break LOCA

Steam Line Break

During 1978 and 1979, Oconee 1 , 2 , and3 ex p erien ced 36 laannal o r antom atic scrams d a rin g fo rced shutdowns (see NDREG 0618 and NnRE6/C3rl496). T his r e s u l t s in a n o n -s p e c if ic r e a c to r t r i p e s tim a te o f 6 /y e a r . A pproxim ately 61% were th e r e s u l t o f e l e c t r i c a l o r steam 6 power co n v ers io n system problem s w hich, in some c a se s , may have im pacted subsequen t p la n t re sp o n se .

The NREP sc reen in g (EG6-EA-5887) fo r a sm allb reak LOCA, 1 x 10 , was used in th i s s tu d y . T hisva ln e i s j x n s i s t e n t w ith th e NDRE6/CR-2497 value o f 8 .3 X 10 /y r f o r PVRs. I t should be no ted th a t t h i s v a lu e may be somewhat h ig h , s ince t r a n s ie n t induced LOCAs a re co n sid e red on the n o n sp e c if ic r e a c to r t r i p even t t r e e .

A viQue equal to the sm all b reak LOCA frequency (10 /y r ) was assumed. T h is va lu e i s a p p lic a b le to a sm all o r m oderate s iz e d steam l in e b re a k . Large steam l in e b reak s would be ex f^ c ted to occur w ith fre q u e n c ie s no g r e a te r th a n 10 /y r .

6 /y r

10 ^ /yr

1 0 "* /y r

Branch P r o b a b i l i t i e s

R eac to r Trip/Demand

T urbine T r ip / R eacto r T rip

A va lne e q u iv a le n t to th e f a i lu r e to t r i p p r o b a b i l i ty developed in WASH- 1400^(3 .6 x 10 /D was employed. Because o f th e 10 /y r frequency c u to f f u sed , sm all v a r i a t io n s in the assumed r e a c to r t r i p p r o b a b i l i ty have no e f f e c t on the sequences id e n t i f i e d in th e s tu d y .

A ll PWR LERs were review ed fo r tu rb in e t r i p , tu rb in e sto p v a lv e , e t c . , f a i l u r e s . While th e re have been s e v e ra l f a i l u r e s o f in d iv id u a l stop v a lv e s ( s in g le steam l in e s ) to c lo s e , only one even t (NSIC 092449 a t Turkey P o in t 3 , 4 ) id e n t i f ie d a t o t a l f a i l u r e of tu rb in e s to p v a lv e s . Assuming ~12 sh u td o w n s/p ian t y e a r (s e e NDREG/CR-1496) and ~350 PWR y e a r s , the number o f tu rb in e s top valve demands i s -4 2 0 0 . One f a i lu r e in th i s number o fd e m a n d s r e s u l t s in a f a i l u r e e s tim a te o f ~2 x 10 /Demand.

3.5xlO~®/d

2 X 10” '*/D

Main F eedw ater R esponse/R eactor T rip

F a ilu r e to Run Back (O verfeed)

Shock E v a lu a tio n id e n t i f i e s fou r

r e a c to r t r i p :

The Oconee P re s su r iz e d Thermal (DPC-RS-1001, January 1982) f a i l u r e s to run back fo llo w in g a

U n it 2 , Septem ber 17 , 1974 U nit 3 , A p ril 30 , 1978 D n it 2 , Jan u a ry 30 , 1980 U n it 3 , March 14, 1980

D uring th e tim e p e rio d co n sid ered in the Oconee study (24 p la n t y e a r s ) , approx im ate ly 144 re a c to r t r i p s o cc u rre d . T his r e s u l t s in a f a i lu r e to run back o f 4 /144 = 0.03/dem and.

0.03/D

B.3

Table B.l (Continned)

Function Discnssion Valne Used

F a i ln r e o f MFW Fnmp Txip C ircu itry /M F ¥ O verfeed

T his t r i p c i r c n i t i s te s te d y e a r ly . A ssn a ii^ a g en e ra l in s t r n a e n ta t io n f a i ln r e r a t e o f 10 /h r (1 ^ -5 0 0 ) r e s n l t s in a f a i l n r e p ro b a b i l i ty o f 4 z 10 "/D .

4 z 10 ^/D

o Loss o f Main Feedw ater

Emergency Feedw ater

NUREG-0560 id e n t i f i e s 5 ev en ts a t B6V p la n ts np to ~4/S /79 ( th e d a te o f IE B n l le t in 79-05A) in w hich feed w ate r was l o s t snbseqnent to a r e a c to r t r i p . I f Oconee has a ty p ic a l r e a c to r t r i p r a t e , then th e ' t o t a l nnaber o f nnschadnled r e a c to r t r i p s on th e se p la n t s np to th a t d a te i s 6 t r i p s / y e a r z 30 .18 y e a rs s in ce c r i t i c a l i t y “ 181 t r i p s . T his r e s n l t s in a lo s s o f feed w ater g iven r e a c to r t r i p p r o b a b i l i ty o f 5/181 “ 0 .0 3 . T his nnmber does n o t in c ln d e in s tm n e n t bns f a i ln r e s which r e s n l te d s im n ltan eo n s ly in r e a c to r t r i p and lo s s o f main feed w a te r .

The emergency feed w ate r system was assnmed to r e q n ire mannal i n i t i a t i o n (becanse of te s t in g o r aw in tenance) ap p rox im ate ly 4 h rs /s io n th . T his r e s n l t s in a p r o b a b i l i ty o f being in . mannal o f 4 hrs/C 30 days z 24 h rs /d a y ) « 5 .6 z 10 /D.

EFT I n i t i a t e d P r io r to Steam G enera to r D ryont

EFW O verfeed (One G e n e ra to r) / I n i t i a t o r

5 .6 z 10"^/D

The EFW le v e l c o n tro l c i r c n i t c o n s is ts o f a le v e l t r a n s m i t t e r on each steam g e n e ra to r , an a s s o c ia te d E/P c o n v e r te r , and flow c o n tro l v a lv e . A d d itio n a l in s tm m e n ta tio n i s p rov ided to change SO le v e l based on w hether o r n o t th e RCPs a re o p e ra t in g . An a l t e r n a t e le v e l c o n tro l channel i s p rov ided in th e even t power i s l o s t to the o p e ra tin g ch an n e l. I t i s assnmed th a t a c c e s s ib le in s tm m e n ta tio n is te s te d m onth ly , and th a t th e le v e l t r a n s m i t t e r s a re e f f e c t i v e ly te s te d m onthly becanse le v e l changes dn ring o p e ra t io n can be c ro ss-cheched among th e S.G. o p e ra tin g and s t a r tn p range le v e l in d ic a t io n s . Based on t h i s , one can ronghly e s tim a te the p r o b a b i l i ty o f o v e r f i l l on i n i t i a t i o n as the p r o b a b i l i ty o f t r a n s m i t t e r f a i ln r e o r c o n v e r te r f a i l n r e o f va lv e f a i l n r e ( ~ 1 0 /^ z 720 h rs ( le v e l c o n t r o l l e r s , IEEB-500),+ 1 z 10 /D (va lve f a i l n r e , WAS-1400)) - 1 ,7 z 10"^/D .

1 .7 z 10 ’ /1>

EFW O verfeed Not T h ro ttle d /O v e rfe e d

I t i s assnmed th a t the EFW system can be p lace d in mannal and e f f e c t iv e ly c o n tro lle d n n le s s the c o n tro l va lv e f a i l s open. Valve f a i ln r e s con- t r i b n t e ~60 p e rc e n t o f th e EFW o v erfeed p ro b a b i l i ty developed above. T h e re fo re , th e p r o b a b i l i ty of f a i l i n g to e f f e c t iv e ly t h r o t t l e an ove rfeed was ass ig n ed a p r o b a b i l i ty o f 0.6/dem and.

0 .6 /D

B.4

Table B.l (Contlaned)

Fimetioii Diioneaioii Value Uied

F a ilu r e o f EFW to I n i t 1a te / Deaand

NnK£G/CBr2497 id e n t i f i e d Emergency Feedw ater S y s |ea f a i l n r e s on deaand. I b i s w alne was 1 .1 z 10 /D in o ln d in g c r e d i t f o r p o te n t ia l r e c t i f i c a t i o n . E zclnd ing the p o s s i b i l i t y of r e c t i f i c a t i o n (as wonld be the case im M d ia te ly a f t e r i n i t i a t i o n and p r io r to any a t t o u t to r e s t a r t ) the observed va ln e was 1 .4 z 10 /D . Oconee observed EFWn n a v a l l a b i l i t i e s a t th e pnap le v e l and in 1980 and 1980 in c ln d e :

1 .4 z 10“ ^ /D

jt£e Date

1 tu rb in e pnap 5/802 tu rb in e pnap 4/813 tu rb in e pump 11/801 tu rb in e pump 6/813 m otor d r iv e n pump 5/802 m otor d r iv e n pnap 3/812 tu rb in e pump 5/81

F o r th e 17 iw nth p e r io d betw een 5 /80 and 9 /8 1 , th e re have been 7 n n a v a i l a b i l i t i e s , which r e s n l t s in an n n a v a i l a b i l i t y p e r pnaip of 7 /(1 t e s t (d eaan d )/ao z 17 aos z 3 p n a p s /p la n t z 3 p la n ts ) ” O.OS/D. With on ly one pnap re q u ire d f o r su ccess , one can d e riv e a system f a i l n r e p ro b a b i l i ty of 0 .0 5 ( f a i l n r e of f i r s t pnaq?) z 0 .1 ( f a i ln r e of s e c o n d / f i r s t ) z 0 .3 , ( f a i l n r e of t h i r d / f i r s t and second) > 1 .5 z 10 /D . T h is i s i n s i s t e n t w ithth e NDEEB/CK-2497 valne o f 1 .4 z 10 /D .

POKV l i f t / n o z a a l NFW o r EFW response

A dequate o p e ra t io n a l d a ta does n o t e z i s t tod e te ia in e th e l i f t p r o b a b i l i ty o f the p re s s n r iz e rPOEV d n ring a n o n -s p e c if ic r e a c to r t r i p s in ce the POBV l i f t s e tp o in t was re v is e d fo llow ing th e m - 2 a c c id e n t . Such l i f t s depend on SCS c o n d itio n sa t th e tim e o f th e t r i p as w e ll as p o te n t ia lv a r ia t io n s in secondary s id e re sp o n se . In l i e n of s p e c i f ic o p e ra t io n a l d a ta , a va lne of 0 .03 /deaand was assumed.

0.03/D

Main Feedw ater R e c o v e re d /In i t ia l Loss o f MFW

A valne o f 0 .5 was assum ed. T his i s c o n s is te n t 0 .5 /D w ith Oconee MFW reco v ery expe rien ce dnring non­s t r e s s s i tu a t io n s (EFW i n i t i a t e d ) o f a p p ro z isu te ly 0 .7 /D (P.M. A brahaason, 1 0 /2 0 /8 2 ) .

EFW I n i t i a t e d A f te r As d e sc rib ed under "EFW I n i t i a t e d P r io r to Steam G enera to r D ryont - F a i ln re o f Q rf to In itia te /D e m a n d ," c o n s id e ra t io n of th e p o te n t ia l f o r sh o r t- te rm r e c t i f i c a t i o n fo llow ing EFW/AFW i n i t i a t i o n f a i l n r e s in PWRs r e s n l t s in a d ecrease in th e p r o b a b i l i ^ o f f a i l i n g to I n U ia t e on demand from 1 .4 z 10 VD to 1 .1 z 10"^/D . T his i s e q u iv a le n t to a g e n e r ic p r o b a b i l i ty o f i n i t i a t i n g EFW/An g iven i n i t i a l f a i l n r e o f 1 - 1 .1 z 10 / 1 . 4z 10 o r 0 .2 4 /demand.

0.24/D

B.5

Table B.l (Continned)

Fnnction Dieonstion Valne Deed

POKV/POBV I s o la t io n ValTe F a i ln r e to Close

NUSEG-0560 r e p o r ts 4 f a i l u r e s o f tbe POKV to c lo se when expec ted once i t had opened o u t of a p p ro x isu te ly 150 a c tu a t io n s . T his r e s n l t s in a f a i l n r e p r o b a b i l i ty o f 4 /150 » 0.027 exc lud ing o p e ra to r a c t io n to c lo se th e b lo ck ^ 01x0 wonld be expected g iv en th e f a i le d -o p e n v a lv e was d e te c te d , a p r o b a b i l i ty o f f a l l i n g to t e r a in a t e POEV flow g iv en th e va lv e was d e te c te d open can be c a lc n la te d as the p r o b a b i l i ty o f va lv e f a i l i n g to r e s e a t t i a e s th e p r o b a b i l i ty o f f a i l i n g to c lo se the POEV b lo ck va lv e due to < ^ r a t o r e r r o r m b lo ck r§Xv» f a i l n r e (0 .027 X (5x10 * + 1 + IxlO"®) - 1 .6xlO ~*/D ).

2 .2 X 10~^/D

However, becanse o f th e o lo sen ess o f th e POEV l i f t p re s s u re to the s a f e ty valve l i f t p re s s u re , soae s i tu a t io n s w hich l i f t th e POEV are expected to a ls o l i f t th e s a f e ty v a lv e s . A ssnaing t h i s o ccu rs 10% of th e t i a e . th a t b o th s a f e ty v a lv e s w i l l l i f t i f c h a lle n g e d , and th a t the j v o b a b i l i t y o f s a f e ty v a lv e f a i l n r e to r e s e a t i s 10 /deaand (VASH-1400), th en th e a d d it io n a l c o n tr ib u t io n f ro a th e se v a lv e s i s 0 .1 X 2 X 0 .0 1 - 2 X 10 /d eaan d . T h is r e s n l t s in a t o t a l f a i l n r e to r e s e a t p r o b a b i l i ty o f 2 .2 x 10“^/D .

Secondary EV F a iln re to Close on Deaand

o F a i ln r e o f Any One Valve to C lose on Deaand

o F a i ln r e o f Any One V alve to Close on Deaand ( I n ta c t S teaa L ine dnring S teaa L ine Break H it ig a t io n )

Based on in fo x a a tio n p rov ided a t th e 10 /20 /82 review a e e t in g , Oconee 1~3 has never had an in d iv id u a l f a i l n r e o f th e se v a lv e s to c lo s e dnring a g e n e ra l shutdown ( in c lu d in g n o n -s p e c if ic r e a c to r t r i p ) o r s t a r tn p . (There have been s e v e ra l a n l t i p l e f a i l n r e s becanse of o th e r i n i t i a t o r s . ) Based on 1978-1980 o p e ra tin g ex p e rie n c e , th e re have been ~10 shutdowns and s t a r tu p s p e r p la n t y e a r . A ssnaing a bypass va lve f a i l n r e on then ex t shutdown, one can c a lc u la te a bonnding f a i l n r e p r o b a b i l i ty a s :l / [ n o . o f observed deaands 1]<• l / [ 4 v a lv e s /p la n t) x (10 shutdowns

+■ 10 s t a r tu p s /p l a n t y e a r) x (Oconee 1 , 2 , 3 , l i f e t i a e th rough 1981) + 1]

- l / [ 4 X 20 X 24 .2 y rs + 1]« 5 X 10 ./D /v a lv e “ 2 X 10~ /D (any o f 4 v a lv e s )The above a n a ly s is a p p l i e s , b u t on ly th e two v a lv e s on th e in t a c t s te a a l in e need to be c o n s id e re d . T h ^ r e s u l t s in a f a i l n r e p ro b a b i l i ty o f 5 x 10 /D /v a lv e x 2 v a lv e s - 1 x 10 /d eaan d .

2 X 10“^/D

1 X 3 “ * /D

B.6

Table B.l (Continiwd)

Fanotlon Diaonsiloa Valne Beed

o F a i ln r e o f Two Valve on the Sane Line to C lose on Deaand

0 F a i ln re o f Two V alves to Close on Deaand ( I n ta c t S teaa L ine Dnring S teaa L ine Break M itig a tio n )

F a i ln r e to I n i t i a t e HPI/Low RCS P re s sn re

While th e re have been fo n r in c id e n ts in which s y s te a f a n l t s have r e s n l te d in tn rb in e bypass v a lv e s f a i l i n g open (U n it 1 . 5 /4 /8 1 ; U nit 2 ,9 /1 0 /7 4 ; U n it 3 . 5 /2 5 /7 5 ; and D n it 3 . 7 /1 3 /7 5 ) , none o f th e se have o ccn rred dnring a shntdown seqnence . The chance o f snch a f a n l t oecn rrin g fo llo w in g a r e a c to r t r i p can be bonnded as fo llo w s: A ssnaing each r e a c to r t r i p in v o lv es a s ix hour p e r io d w hich th e tn rb in e bypass v a lv e s oonld f a i l open and th a t a p p ro x ia a te ly 144 t r i p s have occnrred th rongh 1982 (24 p la n t y e a rs x 6 t r i p s / y e a r ) , the p r o b a b i l i ty o f any of th e fo n r observed f a i ln r e s o e c n rr in g fo llo w in g a r e a c to r t r i p i s (4) x (144 t r i p s ) X (0 .2 5 d a y s / t r i p ) / (24 p ls n t y ea rs ) X _(365 d a y s /y e s r) “ 0 .016 f ro a l l t r i p s o r ~1 x 10 /d eaa n d .

The above a n a ly a is a p p l i e s , b n t on ly th e v a lv e s on th e in t a c t s te a a l in e need be co n s id e re d . This red n ess th e donble va lv e f a i l n r e valne by a f a c to r o f 0 .5 , to 5 X 10 /d eaa n d .

Oconee

1 X lo'^/D

5 X 5~*/D

NUKEG/CR-2497 id e n t i f i e d HPI s y s te a i

deaand. T his v a ln e was 1 .3 X 10"*/observed BPI u n a v a i l a b i l i t i e s a t thele v e l betw een 4 /7 8 and 9/81 (41 p liin c lu d e :

Oconee U n a v a i ls b i l i tv Date3 t r a i n B 11/783 t r a i n A 4/782 pnap A 2/812 pnap B 1/812 pnap B 11/802 pnap B 7/802 pnap B 7/80

1 .3 X 10“^ /D

C onsidering th ese seven f a i l n r e s to be unconnected ( t h i s i s , in a c tu a l i t y , p ro b ab ly n o t so w ith the fo n r Ooonee 2 , pnsQ B f a i ln r e s ) and on b o th a t r a i n and pna^ b a s i s r e s n l t s in the fo llow ing n n a v a i l a b i l i t y e s t i a a t e s :

7 /(4 1 ao s X 2 t r a i n s / p l a n t x 3 p la n t s - 0 .028 and

7 /(4 1 aoa x 3 p n a p s /p la n t x 3 p la n t s - 0 .019With o n ly one t r a i n o r pnap re q u ire d o r sn co ess , one can d e r iv e s y s ta a f a i l u r e p r o b a b i l i t i e s o f

0 .028 ( f i r s t t r a in ) x 0 .1 (second t r a i n / f a i l u r e o f f i r s t t r a in ) - 2 .8 x 10"^/D

and0 .019 ( f i r s t pnap) x 0 .1 (second p n a p /f a i ln re o f f i r s t ) X 0 .3 ( t h i r d p n a p /f a i ln r e o f f i r s t and second) - 6 x 10 /D

These v a lu e s a re c g n a is te n t w ith th e N0KE8/CK-2 va ln e o f 1 .3 x 10 /D , w hich was u sed .

B.7

Table B.l (Contianad)

Fanetion Dlteaesion Value Used

F a i lu r e to S ev ise S6 Level/KCP T rip

F a i lu r e to P royide SG Cooling Steam G enera to r D e p re a a u riz a tio n and Uae o f H o tv e ll and Condenaate B ooa te r Pum pa/Failure o f MFW and EFT Syatema

F a i lu r e to P royide SG C ooling by F u r th e r Steam G enera to r D e p re a a u riz a tio n and Dae of AST Syatem/ F a i lu r e o f HFT and EFT Syatema and F a i lu r e to P roy ide C ooling Uaing th e H otw ell and Condenaate B ooater Pomp

The ateam g e n e ra to r le y e l a e tp o in t ia re y ia e d baaed on a ig n a la from the fo u r RCPa when theae pnatpa a re t r ip p e d . Theae a ig n a la a la o r e a u l t in the re a lig n m en t o f feed w ater flow to th e emergency h e a d e r . F a i lu r e to rew iae th i a le y e l waa aaaumed to be ^dominated by ya lye f a i lu r e a , and a y a lu e of 1 z 10~ /D waa aaaumed.

A y a lu e o f 0 .1 waa aaaumed in th e a tu d y . Ih ia ya lue on ly im pacta f a u l t a on th e n o n -a p e o ifio r e a c to r t r i p aupplem ental reaponae ey en t t r e e .

1 z

A ya lu e of 0 .5 waa aaaumed in th e a tu d y . Thia ya lu e on ly im pacta f a u l t a on th e n o n -a p e c if ic r e a c to r t r i p aupplem ental reaponae eyen t t r e e .

0 .1 /D

0.5/D

B . 8

exunp le , f o r f a i l u r e to t r i p th e RCPs on HPI i n j e c t i o n caused by

a t u r b i n e bypass v a lv e s t i c k i n g open a f t e r a n o n s p e c i f ic r e a c t o r

t r i p o r f a i l u r e to i s o l a t e a s tu c k -o p e n tu r b in e bypass va lve under

s i m i l a r c i rc u m s ta n c e s (sequences S14, SIS , S17, S31, S32, and

S33) .

b . For v e i l d e f in e d ta s k s v b ic b r e q u i r e d s p e c i f i c a c t i o n and w ith_2

m oderate p r e s s u r e on tb e o p e r a t o r , 1 z 10 /D was a s s ig n e d . This

v a lue was u se d , f o r example, f o r f a i l u r e to t r i p tbe RCPs a f t e r

HPI i n j e c t i o n d u r in g a sm a l l -b re a k LOCA. With tbe e x c e p t io n of

tbe sequences i d e n t i f i e d in tb e above p a ra g ra p h , a l l sequences

were c o n s id e re d "m oderate p r e s s u r e " sequences .

c . For dynamic t a s k s , such as t h r o t t l i n g HPI to m a in ta in p r e s c r ib e d

p re s s u r e / t e m p e r a tu r e c o n d i t io n s o r r e i n i t i a t i n g c o o l in g to an

i n t a c t steam g e n e r a to r based on p r e s s u r e and l e v e l i n d i c a t i o n s , 3 —2

X 10 /D was u sed .

d . In a d d i t i o n , i f a p re v io u s o p e r a to r e r r o r bad o c c u rre d , tb e

a p p l i c a b l e e r r o r r a t e f o r tb e b ranch under c o n s id e r a t io n vas

doub led . T h is vas tb e c a s e , f o r example, f o r f a i l u r e to e f f e c t

secondary i s o l a t i o n on a steam l i n e b re a k , g iv e n t h a t tbe o p e ra to r

bad f a i l e d t o t r i p tb e RCPs on HPI i n i t i a t i o n .

Tvo o p e ra to r re sp o n se s i t u a t i o n s in c lu d e d on tb e i n i t i a t o r even t t r e e s

a re no t d i r e c t l y a d d re s sed in NUREG/CR-1278; r a p id o p e ra to r response

r e q u i r e d to m i t i g a t e a steam g e n e ra to r o v e r fe e d and a p l a n t c o n d i t io n t h a t

appeared to be beyond tb e a n a l y s i s a ssum ptions fo r a p a r t i c u l a r i n i t i a t o r .

B.9

in p a r t i c u l a r , a f a i l u r e of a tu r b in e to t r i p , which would r e s u l t in th e

d e p r e s s u r i z a t i o n o f b o th steam g e n e ra to r s fo l lo w in g secondary i s o l a t i o n .

In th e s e c a s e s , th e fo l lo w in g o p e r a to r e r r o r assum ptions were made:

a . For steam g e n e r a to r i s o l a t i o n on main o r a u x i l i a r y feed w ate r

o v e r fe e d (which r e q u i r e s o p e r a to r re sponse on the o rd e r of

m in u te s ) , a v a lue o f 0 .1 was u se d . T h is v a lu e i s lower than

th e NREP sc re e n in g guide v a lue o f ~ 0 .6 f o r t h i s time p e r io d .

However, b a sed on th e s u c c e s s f u l manual t e rm in a t io n o f 10 observed

o v e r fe e d s a t B&W u n i t s w ith o u t main feed pump h ig h l e v e l t r i p s (as

d e s c r ib e d in th e December 17 , 1980 AEOD steam g e n e ra to r o v e r f i l l

o b s e r v a t io n s r e p o r t ) , a v a lu e o f 0 .1 i s c o n s id e re d d e f e n s ib l e .

b . For a s i t u a t i o n i n which th e tu r b in e f a i l s t o t r i p , th e p r o b a b i l i t y

o f an o p e r a t o r ' s a t te m p t in g to r e s t o r e secondary c o o l in g a f t e r

i s o l a t i o n was assumed to be 0 . 5 .

As d is c u s s e d p r e v io u s l y , b ran ch es on the i n i t i a t o r t r e e s dominated by

o p e r a to r a c t io n a r e i d e n t i f i e d w ith th e symbol 0 .

B.4 T h e rm a l-H v d ra u l ic -R e la te d P r o b a b i l i t y V alues

P r o b a b i l i t y v a lu e s d e s ig n a te d 'T /H " on th e e v e n t t r e e s a r e e s t im a te s dom inated

by th e rm al—h y d r a u l i c c o n d i t io n s in th e p l a n t . These e s t im a te s have been

deve loped based on r e s u l t s t o d a te in th e Oconee PTS a n a ly se s and S A I 's

e x p e r ie n c e in p r i o r r e a c t o r p l a n t th e rm a l - h y d r a u l ic a n a ly s e s . In g e n e r a l ,

t h r e e v a lu e s were a p p l i e d : 0 .1 i f th e s t a t e was c o n s id e re d u n l i k e l y , 0 .9

i f th e s t a t e was c o n s id e re d q u i t e l i k e l y , and 0 .5 f o r s i t u a t i o n s in between

t h e s e s . Because of th e s o f tn e s s in th e se numbers, sequences in v o lv in g T/H

B.IO

vftlnes were n o t t r u n c a te d a t 10 ^ / y r n n le s s th e sequence frequency*

assuming a T/H p r o b a b i l i t y o f one, was below 10~ ^ /y r .

B . l l

APPENDIX C

ESTIMATION OF PRESSURE, TEMPERATURE,

AND HEAT TRANSFER COEFFICIENT

c .i iatre.jlBg.liea

The e v a l u a t i o n o f th e r i s k s o f p r e s s u r i z e d t h e m a l shock (PTS) e n t a i l s

th e c o u p l in g o f o v e rc o o l in g in c id e n t even t t r e e s to f r a c t u r e aiechanics

c a l c u l a t i o n o f the p r o b a b i l i t y of v e s s e l c ra c k p ro p a g a t io n . The l in k

between an ev en t t r e e and s t a t e and th e f r a c t u r e a e c h a n ic s c a l c u l a t i o n i s

th e t r a n s i e n t b e h a v io r o f p r e s s u r e ( P ) , te m p era tu re ( T ) , and h e a t t r a n s f e r

c o e f f i c i e n t ( h ) , in th e r e a c t o r v e s s e l downcomer re g io n . That i s , th e P,

T, h t r a n s i e n t p r o f i l e s from the sequence d e f in e d by an even t t r e e end-

s t a t e become in p u ts f o r th e f r a c t u r e mechanics c a l c u l a t i o n . There are

te n s o f m i l l i o n s o f e n d - s t a t e s on o v e rc o o l in g t r a n s i e n t even t t r e e s . Due

to th e c o s t and com plex ity of therm al h y d ra u l i c s and f r a c t u r e mechanics

c a l c u l a t i o n s , i t i s n o t p r a c t i c a l t o e v a lu a te every e n d - s t a t e s e p a r a t e ly .

T h e re fo re , i t becomes n e c e s s a ry to a) reduce the number of e n d - s ta t e s

by s i m i l a r i t y g rouping and b) reduce the number o f th e rm a l-h y d ra u l ic

c a l c u l a t i o n s th rough th e use o f l e s s r ig o r o u s e s t im a t io n te c h n iq u e s .

This appendix summarizes th e approach used to group sequences and e s t im a te

P, T, h p r o f i l e s f o r the Oconee-1 PTS s tu d y . S e c t io n C.2 d e s c r ib e s

the e s t i m a t io n methodology deve loped f o r t h i s s tudy and the approach and

r a t i o n a l e f o r sequence g ro u p in g . S e c t io n s C.3 th rough C.8 p r e s e n t the

r e s u l t s o f e v a lu a t io n s f o r each o f th e major i n i t i a t i n g e v e n t s . These

in c lu d e , main steam l i n e b re a k s (MSLB), tu r b in e bypass v a lve f a i l u r e s (TBV)

C.I

a t f u l l power and a t h o t ze ro power, p o w er-o p era ted r e l i e f v a lve s iz e d

p r im ary b re a k s (PORV LOCA), fe e d w a te r t r a n s i e n t s (FV), and s te a n g e n e ra to r

tu b e r u p tu r e (SGTR). O ther i n i t i a t o r s such as l a rg e - b r e a k LOCAs, l a rg e

main s te a m lin e b reak s a t h o t ze ro power, and s m a l l -b re a k LOCAs a t ho t zero

power were n o t ad d re s se d s p e c i f i c a l l y .

The e s t im a te s a re based on TRAC c a l c u l a t i o n s r e p o r te d by Los Alamos

N a t io n a l L ab o ra to ry ( J . I r e l a n d , e t a l . , "TRAC A nalyses o f Severe

O vercoo ling T r a n s ie n t s f o r the Oconee-1 PVR," LA-UR-83-3182, no d a t e ) ,

RELAF5 c a l c u l a t i o n s r e p o r te d by Idaho N a t io n a l E ng in ee r in g L a b o ra to ry (C.

D. F l e t c h e r , e t . a l . , "RELAPS T herm al-H ydrau lic A n a ly s is o f P r e s s u r i z e d

Thermal Shock Sequences f o r th e Oconee-1 P r e s s u r i z e d Water R e a c to r , " EGG-

NSMD-6343, J u l y 1983), and p l a n t - s p e c i f i c in fo rm a t io n a v a i l a b l e to ORNL.

These so u rc e s were the d a ta base used in the developm ent of th e P,

T, h e s t im a te s in t h i s append ix . Term inology from th e se r e f e r e n c e s i s

u se d e x t e n s i v e ly in t h i s append ix . The w r i t t e n d e s c r i p t i o n s assume r e a d e r

f a m i l i a r i t y w ith th e above named r e p o r t s as w e l l as a v a i l a b i l i t y o f the

r e p o r t s f o r r e f e r e n c e to c o n d i t io n s n o te d in t h i s append ix .

C.2

c.2. Methodology

C .2 .1 G enera l Approach

A f te r an i n i t i a l su rvey o f the d a ta re s o u rc e s and th e sequences i d e n t i f i e d

f o r e s t im a t io n , th e f i v e - s t e p p ro c e s s d e p ic te d in F ig u re C .l was employed

in the development of Oconee-1 p r e s s u r e , te m p e ra tu re , and h e a t t r a n s f e r

c o e f f i c i e n t e s t i m a t e s . T h is approach a llow ed lo g i c a l r e d u c t io n of the

number of c a s e s t o be e v a lu a te d and d e r iv e d the g r e a t e s t b e n e f i t from the

in fo rm a t io n in the TRAC and RELAP c a l c u l a t i o n s .

The f i r s t s te p in v o lv e d th e g roup ing o f s i m i l a r sequences. An e v a lu a t io n

o f th e TRAC and RELAP c a l c u l a t i o n s f o r th e e f f e c t s from d i f f e r e n t o p e ra t in g

s t a t e s p ro v id e d th e c r i t e r i a f o r ass ignm ent of sequences i n t o groups.

B es ides p ro v id in g group ing c r i t e r i a , s t e p 2 developed th e p a ram e te rs f o r

th e cooldown model used on o c c a s io n f o r t h i s s tu d y . To a s s u re c o r r e c t

i n t e r p r e t a t i o n o f c o n d i t io n s d u r in g sequences, the a p p ro p r ia te p a ram ete rs

were a p p l ie d t o th e cooldown model t o d u p l i c a te p o r t i o n s of sequences

c a l c u l a t e d by ISAC o r RELAP. T h is v a l i d a t i o n e f f o r t took p la ce in s te p 3 .

In s te p 4 , the p r e s s u r e , te m p e ra tu re , and h e a t t r a n s f e r c o e f f i c i e n t s were

e s t im a te d . Tem perature c o u ld be e s t im a te d e i t h e r by p iecew ise a p p l i c a t i o n

o f TRAC and RELAP r e s u l t s o r by c a l c u l a t i o n u s in g the cooldown model.

The method s e l e c t i o n depended on the com plex ity of the sequence and th e

a v a i l a b i l i t y o r absence o f d i r e c t l y a p p l ic a b le d a ta from the TRAC o r RELAP

c a l c u l a t i o n s . E a r ly p o r t i o n s of sequences where HPI, f e ed w a te r , p rim ary

loop f lo w s , and downcomer te m p e ra tu re s v a ry r a p id l y were no t d i r e c t l y

a p p l ic a b l e to the cooldown model, so p ie cew ise use o f TEtAC and RELAP

C.3

Resource Data

n

ORNL Specified S eq u en ces

Main s t e a m line b reak s TBV la i iures PORV sized 1.0CAS F e e d w a te r t r a n s ie n ts ~ 130 c a s e s c o n d e n s e d to 97 c a s e s

18 ca lc u la t io n s by INEL (RELAP)

S te p 2 S te p 3

and LANL (TRAC) D eterm ine Applicable C heck c o n s i s t e n c yinclude ____ ► TRAC an d RELAP ^ ^ ol p a r a m e te r s

s te a m line b re a k s c a s e s , ex t rac t by d u p l ica t ing TRACTBV lai iures re levant p a r a m e te r s an d RELAP r e su l t s inPORV, 2", 4” SBLOCAs co o ld o w n m odelSGTR, ove r fe eds

S te p 1 S te p 4 S te p 5

G roup spe c if ied s e q u e n c e s by similarity

EvaluateA. T e m p e ra tu re s by

p ie c e w is e s e lec t io n ol TRAC/RELAP cu rves

D o cu m en t

a n d u s e of c o o ldow n m odel

B. P re s s u re s by p ie c e w ise se le c t io n of TRAC/RELAPcurves

C. H e a t T ransfe r Coeff ic ient by p ie c e w ise s e lec t io n of TRAC/RELAP cu rves

F i g u r e C . l P , T, h e s t i m a t i o n a p p r o a c h .

d a ta vas a p p l i e d . Late in t r a n s i e n t s where the loop flow s a re more

s t a b l e , th e cooldown model was a p p l ie d to p r e d i c t the te m p era tu re s t r e n d s .

The cooldown model was most u s e f u l when the c o n d i t io n s in the re q u e s te d

sequence e v a lu a t io n s d e v ia te d s i g n i f i c a n t l y from those in the TRAC and

RELAP c a l c u l a t i o n s .

P r e s s u r e e s t im a te s were d e r iv e d s o l e l y from o b s e rv a t io n o f p r e s s u r e t r e n d s

in th e TRAC and RELAP c a l c u l a t i o n s . The a b i l i t y of the h ig h head HPI system

in th e Oconee-1 p l a n t to r e p r e s s u r i z e the p r im ary q u ic k ly was r e f l e c t e d by

th e TRAC and RELAP5 c a l c u l a t i o n s . The p re s s u re b e h a v io r of the v a r io u s

c a l c u l a t i o n s was s u f f i c i e n t l y un ifo rm to sugges t t h a t p ie cew ise s e l e c t i o n

o f TRAC and RELAP p r e s s u r e cu rv es was v a l i d .

Heat t r a n s f e r c o e f f i c i e n t s were b ased on p ie cew ise s e l e c t i o n o f TRAC d a ta .

I n g e n e r a l , th e c a l c u l a t i o n s p r e d i c t e d r e l a t i v e l y c o n s ta n t v a lu e s w hile

th e r e a c t o r c o o l in g pumps (RCP) a r e runn ing and s te p down to a lower but

c o n s ta n t v a lu e a f t e r RCP t r i p and e s ta b l i s h m e n t o f n a t u r a l c i r c u l a t i o n .

The h e a t t r a n s f e r c o e f f i c i e n t s p r e d i c t e d by TRAC d id n o t in c lu d e c o r r e c t io n

f o r f r e e c o n v e c t io n e f f e c t s . T h e re fo re , th e v a lu e s were u n d e rp re d ic te d fo r

n a t u r a l - c i r c u l a t i o n flow c o n d i t i o n s . T h is e f f e c t was compensated f o r in

th e f r a c t u r e m echanics c a l c u l a t i o n s by s p e c i fy in g a minimum h e a t t r a n s f e r

c o e f f i c i e n t o f 600 B tu /h f t ^ ° F (3400 W/m^K). Any lower v a lu e s re p o r te d

in t h i s appendix were superceded by th e s p e c i f i e d l i m i t .

The com pleted e s t im a t io n s were documented in s tep 5 . T h is docum entation

com prises S e c t io n s C.3 th ro u g h C.8 o f t h i s appendix .

C.5

C .2 .2 Sequence Grouping

The o v e rc o o l in g sequence ev en t t r e e s fo rm u la ted by ORNL p o sse s s e d over

6 .7 m i l l i o n e n d - s t a t e s . A p p l i c a t io n o f a 10 ^ / y r s c re e n in g l i m i t on even t

f req u en cy reduced th e number o f sequences r e q u i r i n g s p e c i f i c e s t im a t io n to

u n d e r 200.

Some a d d i t i o n a l grouping o f sequences based on component s t a t e s '

s i m i l a r i t i e s f u r t h e r reduced the number of e s t im a te s to 9 7 . However,

g roup ing by component s t a t e s ( i . e . . v a lve s t i c k s open. ICS f a i l s t o run

b ack fe e d w a te r . e t c . ) does n o t accoun t f o r th e th e rm a l -h y d ra u l ic impact of

such s t a t e s . The a c t u a l impact w i l l a l s o depend on th e f u n c t io n o r f a i l u r e

of o th e r system s and on feedback from th e rm a l -h y d ra u l ic impact of such

s t a t e s . By o b s e r v a t io n and e v a l u a t i o n o f s i m i l a r e v en ts in th e TRAC and

RELAP c a l c u l a t i o n s , th e c o n t r i b u t i n g e v e n ts in a sequence were c l a s s i f i e d

as dom inant, m inor, o r in c o n s e q u e n t i a l . Sequences w ith the same dominant

e v e n ts were grouped to g e th e r f o r a n a l y s i s . In l a t e r s t e p s , th e in f lu e n c e

o f minor e v e n ts was e v a lu a te d where p o s s ib le to check th e c o n s i s te n c y of

th e g ro u p in g s . Some sequences were r e a s s ig n e d to o th e r g roups based on

th o se ch eck s .

The g ro u p in g s f o r each of th e i n i t i a t o r s a re d is c u s s e d in S e c t io n s C.3

th ro u g h C .8 .

C .2 .3 Cooldown Model

Most o f the o v e rc o o l in g sequences d e f in e d by th e even t t r e e sc re e n in g

p ro c e s s f e a t u r e e v e n ts t h a t v a ry from th e c o n d i t io n s modeled by Idaho

C.6

N a tio n a l E n g in ee r in g L ab o ra to ry (INEL) and Los Alamos N a tio n a l L abo ra to ry

(LAND. In some i n s t a n c e s , th e d i f f e r e n c e s a re n o t g r e a t , so the TRAC and

RELAP5 c a l c u l a t i o n s a re r e p r e s e n t a t i v e . In o th e r c a s e s , the d i f f e r e n c e s

a re very g r e a t , so t h a t the c a l c u l a t i o n s a re no t r e p r e s e n t a t i v e a t a l l .

To p ro v id e sound e s t im a te s o f te m p e ra tu re in cases where TRAC and RELAP5

c a l c u l a t e d c o n d i t io n s may ap p ly , th e cooldown model was developed . The

cooldown model i s a sim ple therm al model; no h y d ra u l ic c a l c u l a t i o n s a re

perfo rm ed . The model r e q u i r e s mass flow r a t e in fo rm a t io n t h a t i s o b ta in e d

from TRAC and RELAPS r e s u l t s and i s t h e r e f o r e no t a s e l f - c o n t a in e d th e rm a l-

h y d r a u l i c s code. The model i s in te n d e d to be a simple " f i r s t p r i n c i p l e s "

to o l to e v a lu a te the impact of h e a t in g and cooldown mechanisms on system

the rm al re sp o n se w ith a minimum of time and expense.

The assum ptions made to s im p l i fy th e system a re summarized in Table

C . l . The assum ptions o f no h e a t t r a n s f e r l i m i t a t i o n , therm al e q u i l ib r iu m ,

and uniform d i s t r i b u t i o n o f energy s im p l i f y the system to a one-node model,

as shown in F ig u re C .2 . The e r r o r s due to h e a t t r a n s f e r r e s i s t a n c e and

sp ace - t im e e f f e c t s a re most n o t i c e a b l e when th e system i s changing r a p id l y ,

i . e . , a t the b eg in n in g o f most sequences (t<1000 s ) .

The lumped system in F ig u re C.2 may be d e s c r ib e d m a th e m a tic a l ly as an energy

b a l a n c e :

d(MU)

d t

where

d(HU)

“ ^t) + Qjjcp + “ hPI^HPI “ fW®FW “ l®L “ “ ST®ST

svs = r a t e o f change in t o t a l system energyd t

C.7

Table C . l Cooldown model assum ptions

Assnmption J u s t i f i c a t i o n s L im i t a t i o n s Model L im its

1 . No b e a t t r a n s f e r (HT) r e s i s t a n c e between p rim ary and secondary

Large HT a re aLarge HT c o e f f i c i e n t f o rb o i l i n g , c o n d e n sa t io n

Loss o f b e a t flow la g s and d i s e q u i l ib r iu m in fo rm a t io n

Allows lumping o f s e c ­o n d a ry -s id e and p r im a ry - s id e b e a t c a p a c i t i e s

o00

2 . S6 s e c o n d a r ie s in therm al e q u i l ib r iu m

Assumption 1Good app ro x im atio n f o rcboked flow c o n d i t io n s

Not a good ap p ro x im atio n wbere o v e r fe e d i s com pressing steam

Allows use of e n th a lp y t r a n s p o r t model based on cboked flow p r e s s u r e , e n th a lp y c o n d i t io n s

3 . Water in v e n to ry i s w e l l mixed (energy i s un ifo rm ly d i s ­t r i b u t e d )

Assumption 1 N a tu ra l c i r c u l a t i o n flow i s g e n e r a l ly much l a r g e r th a n HPI and secondary f low s , a l low ing e q u i l i b r a t i o n o r approach th e r e t o

E l im in a te s sp ace - t im e e f f e c t sD i f f i c u l t to q u a n t i f y flow s t a g n a t io n e f f e c t s

Allows use o f 1-node m ass-energy b a lan ce

sys

QDecay HeatQpump power

F ig u re C.2 In p u ts and O utpu ts of system h e a t b a la n c e .

C.9

Qjj(t) = decay h e a t in p u t as a f u n c t i o n o f time

(ANS decay h e a t f u n c t io n )

*RCP = Pumping power d e p o s i te d in c o o la n t

~ P roduc t of HPI mass flow and s p e c i f i c e n th a lp y a t HPI nominal te m p e ra tu re vs thermodynamicr e f e r e n c e te m p e ra tu re

" “ hPI ^p ^^HPI " ^ re f^

= p ro d u c t o f feed w a te r mass flow and s p e c i f i c e n th a lp y a t feed w a te r te m p e ra tu re

" ^p ~ ^ re f^

A^H^ = p ro d u c t o f p r im ary le a k flow ( p r e s s u r i z e r su rge l i n e o r b reak ) and s p e c i f i c e n th a lp y o f the l i q u i d a t the h o t te m p e ra tu re (Th)

= *L S -^ re f>

"ST^ST ~ secondary steam flow and s p e c i f i c e n th a lp y f o rs a tu a r a te d steam a t steam g e n e ra to r c o n d i t io n s (T„_)su

- 's r <“ v < SG> S ' SG -

The d e r i v a t i v e of the t o t a l energy may he expanded u s in g th e ch a in ru le

and s i m p l i f i e d as fo l lo w s .

d(MU) dU dN----------S i s ^ — + U — S i s ^^ 2 )

d t d t d t

where

and

M = t o t a l system masssys •’

D = s p e c i f i c energy a t system te m p e ra tu re , p r e s s u r e

= " v <^H - ^ref>

dU dX„— = c --Sd t ^ d t

dMsvs t"= 2 m = “ g p j + ~ “ sT ~ mass c r o s s in g system

d t boundary

C.IO

Substitntion into the expansion of the derivative yields

d(MU) dT„

“ " sy s ^v ~ * ^v^^H “ "^ref^ ^“ hPI “ fW “ “ l " “ ST d t d t

For l i q u i d s , may be assnmed to be equa l to C^. Then s u b s t i t u t i n g the

expanded d e r i v a t i v e i n t o th e energy b a la n c e

dTfl

and th e n c o l l e c t i n g common term s y i e l d s

"«y» S ■ ®D**’ * ®ECP ' ” hP I *BW ’ P**

- t - T j ) )

Note: M = m (t) = M + (iUroT “ « t ■*■ “ m “ )sys syso m ' l L FW ST o

T h is e q u a t io n g iv e s th e change in h o t le g tem p era tu re f o r the combined

a c t io n o f the h e a t in g /c o o ld o w n mechanisms in the model. I f a l l mechanisms

excep t HPI flow a re ta k e n to have ze ro c o n t r i b u t i o n ( i . e . , a re no t a c t i v e ) ,

th e e q u a t io n may be s o lv ed to y i e l d

-mHPIin

“ ^HPIin ^^o ” ^HPIin^sys

which i s the f a m i l i a r e x p o n e n t ia l cooldown model, which form i s v a l i d f o r

feed w ate r o v e r fe e d s and HPI i n j e c t i o n a t ze ro decay h e a t .

To model a sm all steam l i n e b re a k such as an open IBV, i t i s n e c e ss a ry

to s p e c i fy the steam flow r a t e , Such v a lu e s a re no t known a p r i o r i .

To avo id a r b i t r a r y s e l e c t i o n o f such an inqportant p a ra m e te r , a r e l a t i o n s h i p

C . l l

betw een steam flow and b e t le g te m p era tu re was deve lo p ed . For i s e n t r o p ic

cboked f low , tb e steam flow r a t e i s g iven by

= f(P .H ) A P

2wbere f(P .H ) = mass flow ( I b / b / i n . p s i a (ups tream p r e s s u r e ) ) as a

f u n c t io n o f p r e s s u r e , and m ix tu re e n th a lp y . See ASME

steam t a b l e s , f o u r th e d i t i o n . F ig u re 14 .

2A = b re a k (v a lv e ) s i z e ( i n . )

P = upstream p r e s s u r e (p s ia )

By e v a lu a t in g t h i s e x p r e s s io n f o r s a tu r a t e d steam e n th a lp y a t v a r io u s

p r e s s u r e s and ta k in g a power curve f i t a g a in s t co r re sp o n d in g s a t u r a t i o n

te m p e ra tu r e s , tb e e x p re s s io n was co n v e r ted to

Ag^ = A X 1.87045 x lO"^^ j 4 . 32991

which has an accu racy b e t t e r than +3% between 200^F and 500^F upstream

steam te m p e ra tu re . T h is steam r a t e i s r e l a t e d to ho t leg te m p era tu re

th ro u g h an energy b a la n c e around th e steam g e n e r a to r , which in t ro d u c e s a

te rm f o r h o t leg mass flow (m ^).

(C.8)

Given A^ and T^, Tg^ and Ag^ may be c a l c u l a t e d by i t e r a t i o n . The p h y s ic a l

meaning o f t h i s e x p re s s io n i s t h a t the energy t r a n s p o r t e d in by th e loop

flow ( o r h o t leg mass flow) e q u a ls th e h e a t abso rbed by th e secondary .

With s u b s t i t u t i o n of th e e q u iv a le n t term m^ (Tg cooldown,

Eq. C.8 becomes

C.12

^ ^ S c p _ ” hP I^ i)^^H~^HPI^ _

d t CM CM CM CM (C.9)p sys p sys p sys p sys

Rate o f h e a t in g r a t e h e a t in g r a t e cooldown r a t e cooldown r a t esystem = doe to decay + dne to pnmp - dne to HPI - due to h e a tte m p e ra tu re h e a t power flow t r a n s f e r tochange steam g e n e ra to r

where

M = M + (m„DT* - m, + m™ - m„.p) ( t - t ) sys syso TLPIin L ST o

T his e q u a t io n may he so lv ed u s in g Runge-K utta methods to y i e l d T as aJa

f u n c t io n o f t im e . However, im p o rtan t p a ram e te rs such as m^, nip^,

m^ and an i n i t i a l v a lue o f T^ a re r e q u i r e d as in p u t and must be e x t r a c te d

o r e s t im a te d from th e LANL- and IN E L -ca lcu la ted c a s e s .

With Tg and T ^ known, downcomer te m p e ra tu re may be c a l c u l a t e d by s im u la t in g

stream mixing around th e loop d e p ic te d in F ig u re C .3 . S t a r t i n g a t the ho t

l e g , th e f l u i d p a s s e s th rough th e steam g e n e ra to r where i t i s coo led to

te m p e ra tu re as c a l c u l a t e d above. The f l u i d e n t e r s the co ld leg where

i t i s coo led by mixing w i th HPI (and i s h ea te d by the c o o la n t pumps i f

ru n n in g ) , and i t assumes th e minimum c o o la n t te m p e ra tu re . On e n te r in g the

v e s s e l , th e c o o la n t mixes w ith th e v en t v a lv e flow ( a t T^) to y i e l d the

downcomer te m p e ra tu re . Vent v a lv e flow i s a l s o e x t r a c t e d from the LANL-

and IN E L -ca lcu la ted c a s e s . The downcomer tem p era tu re i s d e f in e d by the

fo l lo w in g e q u a t io n

„ _ “ h^SG “ hP I ^H PI ®V ^H ^®RCP^^p^ipC " ----------------- r— —T------------------------

“ h p i “ vwhere

m^ = v e n t v a lv e flow

T|^^ = downcomer te m p e ra tu re

A l l o th e r term s a re as d e f in e d above.

C.13

I^HL- ’’’h

FW-

FW

H b SG VV ' H

’ HPIHP!

DC- ' DC

CoreD ow ncom er

Pum p

G e n e ra to r

S te a m

F i g u r e C.3 S imple l o o p model f o r downcomer t e m p e r a t u r e e v a l u a t i o n .

C.14

This e q u a t io n y i e l d s mass flow w eigh ted average l i q u i d te m p e ra tu re . Because

o f the mass flow w e ig h t in g , th e r e s u l t i n g te m p era tu re approaches t h a t of

th e dom inating f low , which i s th e loop flow (A^) when n a t u r a l c i r c u l a t i o n

i s s t ro n g o r the RCPs a re ru n n in g . The downcomer te m p era tu re would

approach th e HPI te m p e ra tu re on ly i f th e HPI flow were la rg e r e l a t i v e to

th e loop and v e n t v a lv e f low .

C.15

C•3 Main Steam Line Break

The main steam l i n e b re a k sequences were th e s e v e r e s t c a se s from a cooldown

mechanism s t a n d p o in t . The cooldown model i s no t a p p l i c a b l e because o f the

s e v e r i t y . A l l seven of th e OSNL-defined sequences r e q u i r e d steam g e n e ra to r

i s o l a t i o n a f t e r 20 min (1200 s) and r e s t a r t of the r e a c t o r c o o la n t pumps

a f t e r 22 min (1320 s) . For th e TRAC and RELAPS c a l c u l a t i o n s o f th e se

e v e n t s , steam g e n e ra to r i s o l a t i o n was s p e c i f i e d a t 10 min (600 s ) , and

RCP r e s t a r t was r e q u i r e d on a t ta in m e n t of su b co o lin g m argin (300 s fo r

RELAPS and S26 s f o r TRAC). The r e s u l t o f th e se d i f f e r i n g s p e c i f i c a t i o n s

i s a gap o f 800 t o 1000 s (betw een time = 300 and time = 1320 s in the

sequences) where th e re i s n o t s u f f i c i e n t r e p r e s e n t a t i v e d a ta f o r use in

d e t a i l e d e x t r a p o l a t i o n . The TRAC and RELAPS c a l c u l a t i o n s o f th e main steam

l i n e b re a k t r a n s i e n t show r a p id cooldown t r e n d s e a r l y in the sequence,

p r i o r to r e s t a r t of the RCPs. The cooldown r a t e in the downcomer i s a

c o m p lica ted f u n c t io n o f ho t le g te m p e ra tu re p r im ary loop f low , prim ary^

to - s te a m g e n e r a to r secondary h e a t t r a n s f e r (which in t u r n i s a com plica ted

f u n c t io n o f p r e s s u r e , f e e d w a te r f low , en tra in m e n t l o s s e s , e t c . ) , HPI flow ,

v e n t v a lv e f low , and downcomer w a l l - t o - c o o l a n t h e a t t r a n s f e r . A l l o f th e se

p a ra m e te rs w i l l vary to some e x t e n t as the t r a n s i e n t p r o g r e s s e s . The

l i k e l y re sponse would be t h a t th e i n i t i a l h igh cooldown r a t e s w i l l no t

be s u s t a in e d . I n the absence o f o th e r means o f e s t i m a t io n , th e approach

u sed in th e e v a lu a t io n o f th e main steam l i n e b re a k c a se s was to use a

l i n e a r e x te n s io n o f the e a r l y cooldown t r e n d s . T h is assum ption i s c l e a r l y

c o n s e r v a t iv e . A nother c o n s e r v a t iv e assum ption covers th e use o f 212°F as

th e minimum downcomer te m p e ra tu re . Steam g e n e ra to r b o i l i n g h e a t t r a n s f e r

C.16

would d i c t a t e t h i s v a lu e as a mininuai p h y s ic a l l i m i t . HPI and ven t va lve

flow mixing cou ld e i t h e r r a i s e o r lower the te m p era tu re from t h i s assumed

l i m i t . The main steam l i n e b re a h e s t im a te s r e p o r te d in t h i s s e c t i o n are

a l l s u b je c t to th e s e c o n s e r v a t iv e a ssu m p tio n s . The sequences e s t im a te d fo r

o th e r i n i t i a t o r s a re n o t s u b je c t to th e se assum ptions excep t where n o te d .

A f te r the main steam l i n e b re a k e s t im a te s were in c o rp o ra te d in to the

f r a c t u r e m echanics and r i s k assessm en t p o r t i o n s of t h i s FTS s tu d y , an

a d d i t i o n a l d e t a i l e d c a l c u l a t i o n (MSLB p a ra m e tr ic case 4) was perform ed by

Los Alamos u s in g TBAC. In t h i s r e c a l c u l a t i o n , th e model was changed to

p r o p e r ly p r e d i c t an e a r l y t r i p o f the main feed w ate r pumps and improve

measurement o f th e p a ra m e te rs d i c t a t i n g th e manual t h r o t t l i n g o f HPI and

manual r e s t a r t o f one RCP p e r loop . These changes led to t h r o t t l i n g of

HPI a t 302 s and no r e s t a r t o f the RCPs in p a ra m e tr ic case 4 compared to

HPI t h r o t t l i n g and RCP r e s t a r t a t 526 s f o r the base c a s e .

These changes r e s u l t in a d e c l in in g cooldown r a t e in the downcomer,

su g g e s t in g an a sy m p to tic approach to a te m p era tu re h ig h e r than 212°F.

Between the LANL MSLB b ase case and p a ra m e tr ic case 4 , s u f f i c i e n t

in fo rm a t io n on cooldown mechanisms cou ld be e x t r a c t e d to a llow use of

th e cooldown model to g ive a b e t t e r e s t im a te of the sequences examined

in t h i s s e c t i o n . S ince the e s t im a te s g iven in t h i s s e c t io n f e a t u r e

c o n s e r v a t iv e l y low downcomer te m p e ra tu re s , r e v i s i o n would p ro b ab ly y i e l d

h ig h e r te m p e ra tu re s . However, h ig h e r minimum te m p era tu re s may a l s o mean

l a t e r steam g e n e ra to r d ry o u t t im es because h e a t i s r e t a i n e d by th e system

t h a t would o th e rw ise b o i l away th e w a te r in v e n to ry of the broken steam

C.17

g e n e r a to r . F r a c tn r e m echanics c a l c u l a t i o n s would th e r e f o r e be n e c e s s a ry to

a s s e s s th e impact o f P, T, and h r e v i s i o n on v e s s e l f a i l u r e p r o b a b i l i t y .

The seven sequences d e f in e d by ORNL a re d e s c r ib e d in Table C.2 and in the

fo l lo w in g s e c t i o n s . T ab le C.3 d e s c r ib e s th e p e r t i n e n t f e a t u r e s d r iv in g

th e th e rm o h y d rau lic re sponse o f the system . O v e r s p e c i f i c a t io n e x i s t s in

some of the ca se s because o th e r p l a n t p r o t e c t i o n equipment o r th e rm a l-

h y d r a u l i c phenomena p re v e n t the r e a l i z a t i o n o f the s p e c i f i e d c o n d i t io n .

The b a s i s f o r th e e s t i m a t io n and th e e s t i m a t io n p ro ced u re a re p r e s e n te d , as

a r e t a b u l a r d a ta and p l o t s o f p r e s s u r e s and te m p e ra tu re s f o r th e sequences .

C .3 .1 MSLB 1

C .3 .1 .1 B a s is

Use LANL MSLB base case t o de te rm ine cooldown and r e h e a t in g r a t e s .

C . 3 .1 .2 D e p a r tu re s from B as is

a . SG i s o l a t i o n a t 20 min in s te a d o f 10 min in LANL MSLB base c a s e .

b . HPI t h r o t t l i n g and RCP r e s t a r t a t 22 min in s t e a d o f a t a t ta in m e n t o f

su b co o lin g m arg in , as in LANL MSLB b ase c a s e .

C . 3 .1 .3 A p p lic a b le D ata From O ther Cases

a . One-bank IBV f a i l u r e LANL c a se s 5A, SB, SC, show s i m i l a r n a t u r a l

c i r c u l a t i o n d ( te m p ) /d ( t im e ) s lo p e s (~ 0 .3S ^F /s) t o t h a t found in the

MSLB b ase c a s e . F u r th e r , th e s e ca se s have no RCP r e s t a r t and

downcomer te m p e ra tu re s t h a t a s y m p to t i c a l ly approach co r re sp o n d in g loop

SG te m p e ra tu re s . Tem pera tures in SGA d e c re a se , as d e c re a s in g steam

C.18

Table C.2 Main steaai l i n e b re ak s tudy cases

C o n d i tio n

Case MSLS-

3 4 5

Secondary P re s s u re C o n tro l

TSVs c lo s e on t u r b in e t r i p s i g n a l X X X X X X X

TBVs o p e r a t e as d es ig n ed X X X X X X X

SSRVs o p e r a te as des igned ( i f c h a l le n g e d ) X X X X X X X

F eedw ater

NFW runback c o n t r o l l e d by ICS X X X

MFV o v e r fe e d b o th s t e a a g e n e r a to r s X

NFW o v e r fee d t o b roken steam g e n e ra to r X

NFW pump t r i p on h ig h steam g e n e r a to r X X

l e v e l (HW pumps, CB pumps co n t in u e to

o p e r a te )

NFW pumps t r i p a t time 0 .00 X X

EFW i n i t i a t e s on s e t p o in t X X X X X X

EFW f a i l s t o i n i t i a t e a u to m a t i c a l ly X

EFW c o n t r o l l e d t o l e v e l X X X X X

EFW o v e r fee d t o b roken steam g e n e r a to r X

P rim ary P re s s u re C o n tro l

PORV b lo c k v a lv e open X X X X X X X• e

PORV o p e r a t e s as designed X X X X X X**

PORV f a i l s to r e s e a t Xe*

SRVs o p e r a te d as des igned X X X X X X X

C.19

T able C.2 (c o n tin u e d )

C o n d i tio n

Case HSLB-

3 4 5

RCPs t r i p p e d a t HPI + 30 s

Both SGs i s o l a t e d a t 20 min

Both SGs i s o l a t e d a t 5 min

EFW and TBVs r e s t o r e d to i n t a c t SG

a t 21 min

EFW and TBVs r e s t o r e d t o i n t a c t SG

a t 6 min

HPI t h r o t t l e d a t l a t e r o f 22 min

o r 50*’f sn b co o l in g

1 RCP/loop r e s t a r t e d a t l a t e r o f 22

min o r 50°F subcoo ling

F a i l e d PORV i s o l a t e d when system

p r e s s u r e d ro p s below 2400 p s i

X X XX X

X

X

X

X

X X X X X X X

X X X X X X X

O ther c o n d i t i o n s common to a l l c a s e s : f u l l power, decay h e a t 1 .0 t im es ANS. ECCS system s o p e ra te as des igned

I f c h a l le n g e d

C.20

Table C.3 P, T, and h p r o f i l e s f o r MSLBl, MSLB2. and MSLB7

MSLBl .X MSLBl . ? MSLBl .h

Time(s) T(F) Time(s) P (p s ia ) Time( s) H (Btn/h)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2640.050 .0 487.5 50 .0 1000.0 50.0 2640.0

100.0 420.0 100.0 750.0 100.0 285.0200 .0 384.0 200.0 700.0 1320.0 285.0300 .0 348.2 300.0 700.0 1321.0 1160.0400 .0 315.6 360.0 700.0 7200.0 1160.0500.0 293.0 400.0 750.0520.0 286 .0 500.0 854.2870.0 214 .0 520.0 875.0

1200.0 214.0 1200.0 1582.21320.0 214 .0 1320.0 1707.01321.0 296 .0 1650.0 1707.01650.0 214 .0 3750.0 2430.07200.0 484.0 7200.0 2430.0

C.21

g e n e r a t io n r a t e a l lo w s secondary p r e s s n r e and s a t u r a t i o n t e a p e r a t n r e to

d rop . Tbe saae b e h a v io r i s a ssnaed in tbe MSLB sequence .

b . SGB p r i a a r y flow s t a g n a t e s in c a se s SA, 5B, and 5C, p r e v e n t in g SGB

f r o a supp ly ing b e a t t o tb e p r i a a r y . v b ic b would a i t i g a t e downcoaer

cooldown c o n d i t io n s . Flow s t a g n a t io n in MSLB e x t r a p o l a t i o n i s assuaed

to p r e v a i l u n t i l r e s t a r t o f RCPs (one in each lo o p ) .

C . 3 . 1 .4 E x t r a p o la t io n A ssu a p t io n s and P rocedure

a . T e a p e ra tu re — LANL MSLB base case was used to 520 s w ith low est

t e a p e r a t u r e downcoaer c e l l d a ta be ing i n t e r p o l a t e d by s t r a i g b t - l i n e

s e g a e n t s . T h e r e a f t e r , e x t r a p o l a t i o n co n t in u ed on tb e saae l i n e a r t r e n d

to 870 s when c o l d e s t downcoaer r e g io n reached 212°F. This lower

t e a p e r a tu r e l i a i t was c o n s i s t e n t w ith noncboked flow of s t e a a and

fee d w a te r out tbe b roken s t e a a l i n e , as observed in b o th tbe LANL

and INEL c a l c u l a t i o n s . E x t r a p o la t io n o f tbe loop B v o id c o l la p s e

r a t e p r i o r to 520 s s u g g e s ts t h a t tbe v o id s in tb e loop B candy cane

w i l l a l s o c o l la p s e by 870 s . S ince loop B cou ld supp ly b e a t to tbe

p r i a a r y a f t e r c o l l a p s e , tb e e f f e c t o f c o l la p s e w i l l be t o l i a i t f u r t h e r

t e a p e r a t u r e d e c r e a s e s .

Downcoaer t e a p e r a tu r e d rops to n e a r tbe c o ld le g A t e a p e r a t u r e . which

in tu r n i s i n e q u i l i b r i u a w ith tb e secondary o f SGA. A f te r tb e s y s te a

c o o ls enough so t h a t e n t r a i n a e n t l o s s e s d e c l i n e . SGA b e g in s to f i l l .

EFW flow i s c o n t r o l l e d on l e v e l and cea se s p r i o r to i s o l a t i o n a t 1200

s . Tbe SGA w a te r in v e n to ry o f (0 .0 0 0 lb i s b o i l e d ou t by 1360 s

by decay b e a t . RCP d i s s i p a t i o n , and p r i a a r y b e a t in g by SGB. These

C .2 2

e f f e c t s would i n i t i a l l y r a i s e downconer te m p era tu re to 296°F because of

tb e mixing o f warmer w a te rs from SGB w ith tbe downcomer. This e f f e c t

i s a l s o observed in tbe LANL b ase c a s e . Steam g e n e ra to r A d ryou t a t

1360 s would r e s u l t in a downcomer te m p era tu re of 220°F. I f tb e steam

g e n e r a to r d ry o u t p e r io d were ex ten d ed , tbe te m p era tu re s would remain

h ig h e r . A f t e r 1360 s , tb e system r e h e a t s to 50S^F a t 7200 s because

of decay b e a t and RCP power in p u t . T ab le C.3 and F ig u re C.4 summarize

tb e r e s u l t s f o r t h i s c a se .

b . P r e s s u r e — MSLB base case d a ta were used t o 520 s . Tbe system p r e s s u r e

d rops t o 700 p s i a by 200 s . HPI b e g in s to o f f s e t c o o la n t sh r in k ag e by

400 s and in c r e a s e s p r e s s u r e by 1 .04 p s i / s between 400 and 520 s . T h is

r a t e i s assumed to c o n t in u e u n t i l HPI t h r o t t l i n g a t 1320 s (22 min) ,

a f t e r which p r e s s u r e i s assumed c o n s ta n t a t 1707 p s i a (may a c t u a l l y

drop) betw een 1320 s and SGA d ry o u t a t 1360 s . Then r e p r e s s u r i z a t i o n

o ccu rs a t a r a t e o f 0 .3446 p s i / s to tb e PORV s e t p o in t , 2430 p s i a a t

3460 s , fo l lo w in g which th e p r e s s u r e rem ains c o n s ta n t u n t i l th e end o f

the sequence (7200 s ) . Tab le C.3 and F ig u re C.4 summarize the r e s u l t s

f o r t h i s c a s e .

c . Heat T r a n s f e r C o e f f i c i e n t — H eat t r a n s f e r c o e f f i c i e n t s f o r the MSLB

TRAC base case were o b ta in e d from Appendix A of the LANL Oconee-1

r e p o r t . The i n i t i a l v a lue of 2640 B tu /h f t F (15000 w/m k) p e r s i s t s

u n t i l th e RCPs t r i p a t ~50 s . The h e a t t r a n s f e r c o e f f i c i e n t th e n ramps

down w ith loop flow to 285 B tu /h f t ^ ° F (1620 w/m^k) a t 100 s and i s

assumed to rem ain a t t h i s v a lu e u n t i l r e s t a r t o f two RCPs a t 1320 s .

T h is v a lu e n e g l e c t s d e c re a s e s due to r e d u c t io n of n a t u r a l c i r c u l a t i o n

C .2 3

P S r R T ( F )MSLB L

B S00

2200

1 3 0 0

I 4 0 0

1000

3 0 0 0T I M E ( S E C ;

F i g u r e C.4 P r e s s u r e s and t e m p e r a t u r e s f o r MSLBl, MSLB2, and MSLB7,

C.2 4

f l o v s and e l im i n a t io n o f v e n t v a lv e f lo w s . A f te r RCP r e s t a r t , a v a lue

o f 1160 B tu /h f t ^ ° F (6600 W/m^K) was o b ta in e d fo r the rem ainder o f the

t r a n s i e n t . The r e s u l t s a r e summarized in Table C .3 .

C .3 .2 MSLB2

C .3 .2 .1 B as is

LANL MSLB base case to d e te rm in e cooldown and r e h e a t in g r a t e s .

C .3 .2 .2 D ep a r tu re from B a s is

a . MFW o v e rfeed to SGA w ith MFf t r i p on l e v e l .

b . EFW c o n t r o l s t o l e v e l .

C .3 .2 .3 A p p lic ab le D ata From O ther Cases

LANL MSLB case 3 f e a t u r e s NFW pump f a i l u r e s t o t r i p , b u t the r e s u l t i s

o v e r f i l l o f SGB, which t r i p s NFW. L ikew ise , th e MSLB b ase case s u f f e r s

a MFW pump t r i p (low s u c t io n P) when th e ICS i s runn ing back th e fe e d w a te r .

An o v e r fe e d where th e r e i s no v a lv e runback would r e s u l t in MFW pump t r i p

un d er th e s e c o n d i t io n s o r m a lfu n c t io n i f i t rem ained on.

C .3 .2 .4 E x t r a p o la t io n A ssum ptions , P ro c e d u re s , and R e s u l t s

a . T em perature — At th e time of NFW t r i p (45 s) in th e MSLB base

c a s e , th e NFW te m p e ra tu re has s t a r t e d d ropping r a p id l y , i n d i c a t in g

f l a s h i n g to s a t u r a t i o n c o n d i t io n s in th e feed w ate r l i n e s . Heat lo s s

th ro u g h SGA would be l i m i t e d by n a t u r a l c i r c u l a t i o n to app rox im ate ly

370 l b / s e q u iv a le n t in steam w ith an a d d i t i o n a l amount of steam l o s t

C.25

in fe e d w a te r f l a s h i n g . With a nominal SGA feed w ate r r a t e o f 1500

l b / s and assuming no l i q u i d l o s s e s to e n tra in m e n t from the b r e a k , a

n e t in f low o f 1230 l b / s would f i l l the steam g e n e ra to r to 120,000

lb w i th i n 100 s a f t e r RCP t r i p . Downcomer te m p era tu re re sp o n se would

show an e a r l y approach to 212°F b u t p ro b a b ly would n o t drop below

t h a t v a lu e because o f v en t v a lv e f lo w . The case may be approx im ated

by MSLBl and MSLB4. These ca se s p ro v id e the bounds f o r SGA d ry o u t

time a l th o u g h downcomer te m p e ra tu re s may be lower betw een 50-870 s .

MSLBl i s a re a s o n a b le ap p ro x im atio n because the accum ula ted decay h e a t

and p r im ary h e a t in v e n to ry would be cap a b le of e v a p o ra t in g th e excess

w a te r 0 6 0 ,0 0 0 lb ) in SGA p lu s an a d d i t i o n a l 100-200 I b / s o f EFW

and t h e r e f o r e would be a t the same s t a t e as MSLBl a t i s o l a t i o n (1200

s) . Table C.3 and F ig u re C.4 summarize th e r e s u l t s f o r the ro ugh ly

e q u iv a le n t MSLBl c a s e .

b . P r e s s n r e — P r e s s u r e s f o r p o r t i o n s o f th e t r a n s i e n t w i l l be l e s s th an

th o se f o r f i l e MSLBl. Use o f MSLBl would th e r e f o r e be c o n s e r v a t iv e .

c . Heat T r a n s f e r C o e f f i c i e n t — Used same v a lu e s f o r f i l e MSLBl.H.

C .3 .3 MSLB3

C .3 .3 .1 B a s is

LANL MSLB p a ra m e tr i c case 3 (s team l i n e b re a k w i th runaway f e e d w a te r ) .

C .3 .3 .2 D e p a r tu re s from B as is

a . EFW a c t u a t e s and c o n t r o l s on l e v e l .

C .2 6

#

b . I s o l a t i o n o f SGA a t 1200.

c . R e s t a r t 1 RCP/loop and t b r o t t l e HPI a t 1320 s .

C .3 .3 .3 A p p lic a b le Data from O ther Cases

I n LANL MSLB b ase c a s e , t o t a l EFW and HWP/CBP flow r a t e to SGA i s 400 I b / s ;

one-bank TBV f a i l u r e cases LANL SA, SB, SC show downcomer te m p e ra tu re s ;

a s y m p to t ic a ly approach ing r e s p e c t iv e SG te m p e ra tu re s .

C .3 .3 .4 E x t r a p o la t io n A ssum ptions, P ro ced u re s and R e s u l t s

a . T em pera tu res — In MSLB p a ra m e tr i c case 3 , the MFW pumps do no t t r i p

u n t i l h ig h l e v e l in SGB i s e n co u n te red a t 331 s . T h e re fo re , th e minimum

downcomer te m p era tu re p r o f i l e f o r p a ra m e tr ic case 3 was employed to

330 s . A te m p era tu re o f 310**F i s o b ta in e d a t t h i s p o in t . P r i o r

t o NFW pump t r i p , a fe ed w a te r flow r a t e o f ap p ro x im ate ly 440 l b / s

t o SGA i s o b ta in e d . The flow r a t e a f te rw a rd s i s 330 l b / s . These

v a lu e s compare w i th 400 I b / s f o r EFW and HW/CB pump t o t a l flow r a t e

f o r th e LANL MSLB base c a s e . Pump head cu rves and flow r e s i s t a n c e in

th e EFW sp ray r in g may accoun t f o r th e s i m i l a r i t i e s . The e f f e c t of

f e e d w a te r e n tra in m e n t l o s s e s from SGA cou ld n o t be p ro p e r ly e v a lu a te d .

For e x t r a p o l a t i o n p u rp o s e s , an EFW-HW/CB pump t o t a l flow o f 440 l b / s

was assumed. T h e re fo re , th e c o o l in g t r e n d i s co n tin u ed u n t i l th e A-

loop c o ld le g s re a c h 212^F a t 904 s . T h is te m p era tu re w i l l p e r s i s t

u n t i l r e s t a r t o f the RCPs a t 1320 s . Water s t a r t s t o accum ulate in SGA

due to th e n a t u r a l c i r c u l a t i o n mass flow l i m i t a t i o n on h e a t t r a n s f e r .

A pprox im ate ly 60 ,000 lb o f w a te r w i l l be on hand in SGA a t i s o l a t i o n .

At th e r e s t a r t o f th e RCPs (1320 s ) , downcomer te m p era tu re w i l l jump

C.27

to th e p rim ary av e ra g e , 270°F, and drop to 228^F a t 1350 s as the

SGA secondary d r i e s o u t . T h e r e a f t e r , th e system r e h e a t s a t 0 .0 4 8 9 °F /s

u n t i l 7200 s when i t re a c h e s S ld ’ F ( se e Table C.4 and F ig u re C .S ) .

b . P r e s s u r e — System p r e s s u r e d rops t o 800 p s i a t 125 s and th e n in c re a s e s

a t 0 .7 7 p s i / s u n t i l HPI t h r o t t l i n g a t 1320 s . P r e s s u r e i s 1722 p s i

a t t h a t p o i n t . T h e r e a f t e r , system r e h e a t in c r e a s e s p r e s s u r e by 0.3446

p s i / s u n t i l th e PORV s e t p o in t i s reached a t 3375 s and rem ains

c o n s ta n t th rough 7200 s ( s e e Table C.4 and F ig u re C .5 ) .

c . Heat T r a n s f e r C o e f f i c i e n t — While RCPs a re ru n n in g , th e h e a t t r a n s f e r

c o e f f i c i e n t s a re th e same as f o r co r resp o n d in g p o r t i o n s o f MSLBl. The

s i m i l a r n a t u r a l c i r c u l a t i o n r a t e s of MSLBl w i l l cause s i m i l a r v a lu e s

o f h . T h e re fo re , th e h v a lu e s p r e d i c t e d f o r MSLBl app ly to t h i s case

a l s o ( s e e Table C .4 ) .

C .3 .4 MSLB4

C.3 .4 .1 B as is

LANL MSLB b a se c a s e .

C.3 .4 .2 D e p a r tu re s from B as is

Same as MSLBl excep t EFW le v e l c o n t r o l f a i l s , le a d in g to o v e r fe e d o f SGA.

C .3 .4 .3 A p p lic a b le Data From O ther Cases

See MSLBl.

C.3 .4 .4 E x t r a p o la t i o n A ssum ptions and P rocedu res

C .2 8

#

Tab le C.4 P, T, and b p r o f i l e s f o r MSLB3

MSLB3 .T MSLB3 . ? NSLB3 .b

Tiffle(s) T(F) Time(s) P (p s ia ) Time(s) H(Btu/b)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2640.050 .0 477 .0 50 .0 1000.0 50.0 2640.0

330.0 390.0 125.0 800.0 100.0 285.0904.0 212 .0 1320.0 1722.0 1320.0 285 .0

1320.0 212 .0 3375.0 2430.0 1321.0 1160.01321.0 270.0 7200.0 2430.0 7200.0 1160.01350.0 228 .07200.0 514.0

#C .2 9

PSIf l - T ( DMSLB3

2 S 0 0 S 5 0 r

^ 2 0 0 5 5 0

1 8 0 0 4 5 0

1 4 0 0 3 5 0

r\

1 0 0 0 2 5 0

6 0 0 1.50

I ' V1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 S 0 0 0 7 0 0 0

TIME(SEC)

F i g u r e C.5 P r e s s u r e s and t e m p e r a t u r e s f o r MSLB3.

C .3 0

a . T e n p e ra tu re — Case i s tb e same as NSLBl to 1320 s . Minimum te m p era tu re

o f 212°F i s reached a t 870 s , as in HSLfil, E n tra inm en t lo s s e s cou ld

n o t be e v a lu a te d and were c o n s e r v a t iv e ly ig n o red . SGA and steam

l i n e A w a te r in v e n to ry a t i s o l a t i o n (1200 s) i s 150,000 lb compared

t o 60,000 lb f o r MSLBl a t same i n s t a n t . N a tu ra l c i r c u l a t i o n flow s

l i m i t e d cooldown r a t e p r i o r t o i s o l a t i o n . A f te r RCP r e s t a r t a t 1320 s ,

downcomer te m p e ra tu re r i s e s t o 296°F due to mixing o f downcomer and SGB

w a te r s , as d e s c r ib e d in MSLSl. Downcomer te m p era tu re r e t u r n s t o 212°F

a t 1380 s as SGB and p r im ary system h e a t in v e n to r i e s a re ex h au s ted ,

b o i l i n g 70 ,000 lb o f w a te r from SGA in the p ro c e s s . Decay h e a t and

RCP h e a t in p u t (12725 B tu /s f o r two pumps) b o i l d ry th e rem aining w a te r

(80 ,000 lb ) by 4090 s . System h e a t a t 0 .0 4 8 9 °F /s r e tu r n s the system

to 364^F a t 7200 s ( s e e Tab le C.5 and F ig u re C . 6 ) .

b . P r e s s u r e — P re s s u re behaves s i m i l a r l y to MSLBl to 1320 s , t h a t i s ,

d e p r e s s u r i z a t i o n to 700 p s i by 200 s , r e p r e s s u r i z a t i o n to 1707 p s i a t

1320 s . P r e s s u r e i s assumed to h o ld c o n s ta n t (would p ro b ab ly drop

siMBewhat in s te a d ) a t 1707 p s i a u n t i l SGA dryou t a t 4010 s , s in c e HPI

has been t h r o t t l e d and th e r e i s no system r e h e a t du r in g t h i s p e r io d .

A f te rw a rd s , p r e s s u r e c lim bs a t .33446 p s i / s t o PORV s e t p o in t (2430

p s i a ) a t 6190 s and rem ains u n t i l 7200 s ( see Table C.5 and F ig u re

C.6) .

c . Heat T r a n s f e r C o e f f i c i e n t — Case i s i d e n t i c a l to NSLBl (see Table

C.5) .

C.31

T able C.S P, T, and h p r o f i l e s f o r MSL£4

MSLB4 .T NSLB4 . ? NSLB4 .h

TineCs) T(F) Tiaie( s) P (p s ia ) XiBe(s) H(Btn/b)( f t* * 2 F )

5 0 .0 487.5 50 .0 1000.0 50.0 2640.0100 .0 420 .0 100.0 750 .0 100.0 285 .0200 .0 384 .0 200.0 700 .0 1320.0 285 .0300 .0 348.2 300.0 700 .0 1321.0 1160.0400 .0 315.6 360.0 700 .0 7200.0 1160.0500.0 293 .0 400.0 750 .0520 .0 286 .0 500.0 854.2870.0 212 .0 520.0 875.0

1200.0 212 .0 1200.0 1582.21320.0 212 .0 1320.0 1707.01321.0 296 .0 3430.0 1707.01380.0 212 .0 5530.0 2430.04090.0 212 .0 7200.0 2430.07200.0 364 .0

C.3 2

P S I f t TCF)MSLB4

1 8 0 0 4 5 0

1 4 0 0 3 5 0

1 0 0 0 2 5 0

6 0 0 1506 0 0 010000

TIM E(SE C)

F i g u r e C.6 P r e s s u r e s and t e m p e r a t u r e s f o r MSLB4.

C.33

C .S .5 NSLBS

C.S .5 .1 B as is

LANL MSLB base c a s e .

C .S .5 .2 D e p a r tu re s from B a s is

Main f e e d v a te r pumps t r i p a t time 0 . 0 . HW/CB pumps and EFW fu n c t io n

p r o p e r ly .

C .S .5 .S A p p lic a b le Data from O ther Cases

See NSLBl.

C .S .5 .4 E x t r a p o la t i o n A ssum ptions . P ro c e d u re s , and R e s u l t s

a . Tem perature — Loss o f MFW a t time o f 'b r e a k would reduce w a te r a v a i l a b l e

f o r b o i l i n g in SGA o ver f i r s t 50 s o f t r a n s i e n t from 71,500 lb t o

o n ly 25 ,000 lb . As a r e s u l t , te m p e ra tu re d rops to 492**F r a t h e r than

487°F in MSUBl. T h e r e a f t e r , th e same cooldown s lo p e s from MSLBl a re

used to p r o j e c t te m p e ra tu re s a t S50 s (S88^F) and 1150 s (212^F).

An accum ula ted in v e n to ry o f 60 ,000 lb o f w a te r in SGA i s ex pec ted a t

i s o l a t i o n . From 1S20 s on, th e b e h a v io r i s ta k e n to be th e same as

NSLBS (s e e Table C.6 and F ig u re C . 7 ) .

b . P r e s s u re — Since th e i n i t i a l c o o lo f f w i l l be l e s s s ev e re than the

base c a s e , d e p r e s s u r i z a t i o n to th e HPI s e t p o in t would be s l i g h t l y

d e la y e d . The h e a t c o n t r i b u t i o n o f SGB to th e p r im ary i s expec ted t o

s u s t a i n p r im ary p r e s s u r e , as o ccu rred in NSLBS. In th e absence o f

any re a s o n a b le way to p r e d i c t th e d e la y o r e x t e n t o f d e p r e s s u r i z a t i o n .

C.34

Table C.6 P, T, and h p r o f i l e s f o r MSLB5

MSLBS .T NSLB5 .? NSLB5; .h

Time(s) T(F) Time( s) P (p s ia ) Time(s) H(Btu/h)(f t**2F)

0 .0 555.0 0 .0 2180.0 0 .0 2640.050 .0 493 .0 50 .0 1000.0 50.0 2640.0

350 .0 388.0 125 .0 800.0 100.0 285.01150.0 212 .0 1320.0 1722.0 1320.0 285.01320.0 212 .0 3375.0 2430.0 1321.0 1160.01321.0 270.0 7200.0 2430.0 7200.0 1160.01350.0 228.07200.0 514.0

C.3 5

PSIR- T(F) MSLBS2 6 0 0

2200

1 8 0 0

1 4 0 0

1000

6 0 07 0 0 04 0 0 02000 3 0 0 00 1000

TIME(SEC)

F i g u r e C.7 P r e s s u r e s and t e m p e r a t u r e s f o r MSLBS.

C .3 6

th e use o f th e p r e s s u r e curve f o r NSLBS would r e p r e s e n t a c o n s e rv a t iv e

e s t i n a t e ( s e e Table C.6 and F ig u re C .7 ) .

c . Heat T r a n s f e r C o e f f i c i e n t — Case i s i d e n t i c a l to MSLBl (see Table

C.6) .

C .S .6 MSLB6

C .S .6 .1 B as is

LANL MSLB b ase case f o r i n i t i a l response of system fo r t r a n s i e n t , LANL

Rancho S eco -type t r a n s i e n t f o r response o f system to r e f i l l of dry SGB.

C .S .6 .2 D e p a r tu re s From Base Cases

a . Loss o f a l l main feed w a te r flow time 0 . 0 .

b . EFW in manual c o n t r o l .

c . SGs i s o l a t e d a t 5 min.

d. SGB r e s t o r e d a t 6 min w ith f u l l EFW flow .

C .S .6 .S A p p lic a b le D ata from O ther Sources

Not a p p l i c a b l e .

C .S .6 .4 E x t r a p o la t io n A ssum ptions, P ro c e d u re , and R e s u l t s

a . Tem perature — Along w ith th e l o s s o f main feedw ate r a t the beg inn ing

o f th e sequence , i t i s assumed t h a t the h o tw e l l /c o n d e n sa te b o o s te r

pumps a re a l s o u n ab le to d e l i v e r flow to the a f f e c t e d steam g e n e ra to r .

As a r e s u l t , SGA d r i e s ou t v e ry q u ic k ly (p ro b ab ly l e s s th an 20 s)

C.37

because of th e l i q u i d e n t ra in m e n t du r in g the i n i t i a l blowdown. From

th e LANL MSLB c a l c u l a t i o n , th e loop A downcomer r e g io n reac h es SIO^F

a t t h i s moment and th e loop B downcomer rem ains n e a r S70*’f . Having

l o s t a l l o f i t s w a te r in v e n to ry , SGA no lo n g e r c o n t r i b u t e s t o system

cooldown, and the downcomer te m p era tu re soon r e t u r n s to the ho t leg

te m p e ra tu re , > S70^F. SGB d r i e s ou t by about SO s i n t o th e t r a n s i e n t .

The cooldown model was used t o e x t r a p o la t e a system te m p e ra tu re r i s e

to SSS^’f by 6 min (360 s) when EFW is r e s t o r e d to SGB. With EFW

r e s t r i c t e d to SGB o n ly and th e IBVs on SGB c o n t r o l l i n g to p r e s s u r e ,

th e system (h o t le g ) te m p e ra tu re s low ly d e c re a s e s t o 548°F. Downcomer

te m p e ra tu re d e c re a se s t o 534°F a t 460 s because o f mixing o f co ld HPI

w i th e v e r - r e d u c in g amounts o f loop flow , more than o f f s e t t i n g system

h e a tu p . However, as HPI flow d e c re a s e s as th e system re a c h e s PORV s e t

p o in t p r e s s u r e a t 200 s , some mixing e f f e c t s and in c re a s e d loop flow

t o HPI flow r a t i o cause th e downcomer te m p e ra tu re to r i s e to 546°F and

t o co n t in u e to r i s e t o SS6°F a t i n i t i a t i o n of EFW a t 360 s . Assuming

a n a t u r a l c i r c u l a t i o n flow o f 900 I b / s in loop B, m ain tenance o f the SG

e x i t te m p era tu re a t S48°F, 70 l b / s o f HPI flow , and a v e n t v a lv e flow

o f 45 I b / s , th e average downcomer te m p era tu re would f a l l from S56°F a t

360 s t o Sld^’p b e f o r e 460 s because of EFW i n i t i a t i o n . The cooldown

i s n o t as d ram a tic as in th e Rancho S eco-type o f even t b e c a u se , in t h i s

c a s e , o n ly one SG i s in v o lv ed and EFW is c o n t r o l l e d t o l e v e l . A f te r

th e SG f i l l s t o l e v e l , th e downcomer te m p era tu re h o ld s s te a d y a t around

515°F because of th e TBV o p e r a t io n on SGB and c o n t in u e d HPI flow .

At 1200 s th e HPI i s t h r o t t l e d and one RCP p e r loop i s r e s t a r t e d .

T h is r e s u l t s in e x c e l l e n t mixing in the downcomer w i th a te m p era tu re

C .3 8

equa l to th e mean o f th e ho t leg and SGA e x i t te m p e ra tu re s . Downcomer

te m p era tu re r i s e s to 564^F soon a f t e r RCP r e s t a r t and decays to 548°F

by 1420 s , a f t e r which SGB r e g u l a t i o n keeps the system a t 548°F f o r

th e rem ainder o f th e sequence ( s e e Table C.7 and F ig u re C .8 ) .

b . P r e s s u r e — The com bina tion o f main steam l i n e b reak and r e a c to r t r i p

cau ses HPI i n i t i a t i o n ( s e t p o in t 1500 p s ia ) a t 20 s . However, th e

prompt b o i l - d r y of SGA because of th e b reak and SGB because o f lo s s

o f b o th MFW and EFW cau ses r a p id system r e h e a t , which, a long w ith HPI

flow , r e s u l t s in an e q u a l ly r a p id r e p r e s s u r i z a t i o n . The PORV s e t p o in t

p r e s s u r e , 2430 p s i a , i s reached a t 200 s (compare w ith 226 s f o r the

Rancho S eco -type seq u e n c e ) . P r e s s u r e d e c re a se s upon r e s t a r t of the

RCPs because o f enhanced cooldown and c o o la n t s h r in k a g e . LANL cases

5A and 5B c a l c u l a t e d p r e s s u r e r e d u c t io n s on the o rd e r of 500 p s i on

RCP r e s t a r t : a s i m i l a r t r e n d was assumed h e re . A f te r reac h in g 1900

p s i a a t 1300 s , th e p r e s s u r e i s assumed to in c re a s e a t 0 .34 p s i / s , as

in th e LANL MSLB c a l c u l a t i o n . However, p r e s s u r e reco v e ry may no t be

s i g n i f i c a n t because th e system te m p e ra tu re s a re n e a r the ho t s tandby

l e v e l so t h a t r e h e a t in g and expans ion w i l l be minimal ( s e e Table C.7

and F ig u re C . 8 ) .

c . Heat T r a n s f e r C o e f f i c i e n t — Heat t r a n s f e r c o e f f i c i e n t d rops from 28200 i\ 0 i\

B tu /h f t F a t 50 s t o 285 B tu /h f t F a t 100 s because of t r i p and

spindown o f th e RCPs. The n a t u r a l c i r c u l a t i o n va lue p e r s i s t s u n t i l

r e s t a r t of one RCP p e r loop a t 1200 s , whereon th e va lue clim bs to

2o1160 B tu /h f t F f o r th e rem ainder of th e sequence ( s e e Table C .7 ) .

C.39

Tab le C.7 P, T, and h p r o f i l e s f o r MSLB6

MSLB6 .T MSLB6 . ? HSLB6 .h

Time( s) T(F) Time(s) P (p s ia ) Time(s) H (Btn/h)(f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2640.020 .0 510.0 20 .0 1500.0 50.0 2640.050.0 566.0 200.0 2430.0 100.0 285 .0

160.0 534.0 1200.0 2430.0 1200.0 285 .0200.0 546.0 1300.0 1900.0 1201.0 1160.0260.0 550.0 2850.0 2430.0 7200.0 1160.0360.0 556.1 7200.0 2430.0460.0 515.0600.0 514.0

1200.0 514.01201.0 564.01240.0 561.01300.0 555.01360.0 550.01400.0 548.07200.0 548.0

C.4 0

P S I f l TCP)MSLBG

2 6 0 0 6 5 0

-T

1 8 0 0

1 4 0 0

1000

6 0 0 0 2 0 001 7 0 0 0

T I M E ( S E C )

F i g u r e C.S P r e s s u r e s and t e m p e r a t u r e s f o r MSLB6.

C.4 1

C .3 .7 MSLB7

T h is case f e a t u r e s th e same sequence as MSLBl excep t t h a t th e PORV i s

assumed t o f a i l open when c h a l le n g e d and i s i s o l a t e d when p r im ary p r e s s u r e

d rops bach below 2400 p s i . I n MSLBl, th e PORV i s no t c h a l le n g e d u n t i l

3460 s and th e r e i s no m ajor h e a t source to keep th e system p r e s s u r e up.

T h e re fo re , th e b lo c k v a lv e co u ld he c lo s e d p ro m p tly . T h is case would th en

be a s u b s e t o f MSLBl ( s e e Table C.3 and F ig u re C .4 ) .

C .4 2

c.4 Tttrb ine Bypa»g F » il i i re$ > t F u l l Power

C .4 .1 ORNL-Defined TBV Cases (19 T o ta l )

ORNL d e f in e d 19 tu r b i n e bypass v a lv e f a i l u r e ca se s f o r f u l l pover

o p e r a t io n s . These were s o r te d in t o 10 groups d es igned to have s i n i l a r

t r a n s i e n t r e s p o n s e s , e s p e c i a l l y in the l a t e r s ta g e s when te m p era tu re s are

lo w e s t . T ab le C.S d e s c r ib e s th e c h a r a c t e r i s t i c s o f the sequences and l i s t s

group a s s ig n m e n ts . The t r a n s i e n t s a re e v a lu a te d by groups below.

C .4 .1 .1 Base

TBV f a i l u r e s in one loop — LANL 5A, 5B, 5C.

TBV f a i l u r e s in two loops — LANL 6 k , 6B, 6C.

C .4 .1 .2 D e p a r tu re s from Bases

a . A l l s tudy c a se s f a i l , on ly one TBV in a bank. LANL cases f a i l , bo th

TBVs in a bank .

b . A l l s tudy c a s e s have EFW o p e ra te as d es igned and c o n t r o l SG in v e n to ry

to l e v e l . A l l LANL cases f e a t u r e runaway feed w a te r .

c . The s tudy c a se s f e a t u r e a v a r i e t y o f MFW b eh a v io rs (o v e r fe e d s t o one or

b o th SGs, normal runback , and t r i p s c o in c id e n t w ith tu r b in e t r i p an d /o r

r e a c t o r t r i p ) . The LANL cases a l l f e a t u r e o v e rfeed s to SGA or bo th

SGs.

C.43

Table C.S F u l l power TBV f a i l u r e c a se s g ro u p in g s

C o n d itio n

Case (TBV-)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Secondary P re s s u re C o n tro ls

1 TBV open SGA

1 IBV open SGA, SGB

1 IBV open SGA, 1 SRV open SGA

X X Z Z X X Z X X

X

X X XX X X X

MFW runback as d esig n ed

MFW o v e rfee d SGA, h ig h le v e l t r i p

MFW o v e rfee d b o th SGs, HL t r i p

MFWP t r i p a t tim e = 0 ,0

EFW c o n tro l to le v e l

X X X X X X X X X X

X X

X X

X X X X X X X X X X X X X X X X X X X

T able C.8 (c o n tin u e d )

oLn

Case (TBV-)*

C o n d itio n 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 13 14 15 16 17 18 19

P rim ary P re s s u re C o n tro ls

PORV b lo c k v a lv e c lo se d X

PORV o p e ra te s p ro p e r ly X X X X X X X X X X X X X Xee

PORF f a i l s to r e s e a t X X Xee

SRV f a i l s to r e s e a t X X X X

O o era to r A c tio n s

RCP t r ip p e d a t HPI + 30 s X X X X X X X X X X X X X X X X X X X

No o th e r a c t io n s X X X X X X X X X X X X X X

SG i s o l a t i o n a t 20 m in, SGB re s to r e d a t 2 1 min X X X X X

HPI t h r o t t l e d l a t e r o f 22 min o r 50°F su b co o lin g X X X X X

1 RCP/loop r e s t a r t l a t e r o f 22 min o r 50°F X X X X X

su b co o lin g

Group number (IBVG—) 1 1 2 3 2 3 4 5 1 6 8 7 6 4 6 5 9 1 0 1 0

O tber c o n d it io n s common to a l l c a s e s : f u l l pow er, decay b e a t 1 .0 tim es ANS, a l l ECCS com ponents o p e ra te as d esig n ed

I f ch a lle n g ed

c . 4 . 1.3 A p p lic a b le Data froai O ther Cases

E a r ly b e h a v io r of system w ith MFW t r i p a t time = 0 .0 i s a v a i l a b l e from

LANL Rancho S eco -type t r a n s i e n t . The LANL and INEL c a se s on PORV f a i l u r e s

and PORV-sized h o t le g LOCAs a re o f some l i m i t e d use f o r the s tudy cases

in c lu d in g such f a i l u r e . The l i m i t a t i o n s stem from u a t e i r - s o l id c o n d i t io n s

i n the s tudy c a se s compared t o normal p r e s s u r i z e r c o n d i t io n s a t the s t a r t

o f th e LANL and INEL c a s e s .

C .4 .1 .4 E x t r a p o la t i o n A ssumptions

a . T em perature

One-Loop TBV F a i l u r e — A p p l ic a t io n o f the cooldown model to a one loop

TBV f a i l u r e r e q u i r e s knowledge o f n a t u r a l c i r c u l a t i o n and v e n t v a lv e flow

r a t e s and o f th e e f f e c t s o f HPI i n j e c t i o n on s ta g n a te d loop co ld leg

te m p e ra tu r e . LANL cases 5A and 5B were examined w i th re g a rd to th e se

r e q u i r e m e n ts . The r e s u l t i n g d a ta and assum ptions a r e : ( 1 ) . Loop A n a t u r a l

c i r c u l a t i o n rem ains s tead y a t about 1023 l b / s from 400 s u n t i l 1500 s

and i s assumed t o co n t in u e u n t i l 7200 s . Loop B s t a g n a te s a t about 600

s and i s assumed to rem ain so u n t i l 7200 s . The s t a g n a t io n of loop B

i s due to SGBs be ing warmer than th e p r im ary . The d e n s i t y d i f f e r e n c e s

and c o r re sp o n d in g buoyancy e f f e c t s from h ig h e r loop te m p e ra tu re c a n c e l the

f o r c e s in th e v e s s e l t h a t would d r iv e c i r c u l a t i o n in th e loop . ( 2 ) . Vent

va lve mass flow r a t e s co r resp o n d in g to 264 I b / s (120 k g / s ) commence a t 600

s and h o ld s te a d y th rough 1500 s and a r e assumed to c o n t in u e to 7200 s

( v a l i d a s long as SGB rem ains s t a g n a n t ) . ( 3 ) . U n th r o t t l e d HPI f low s t o t a l

40 I b / s (18 K g/s) in loop A and 30 I b / s (14 k g / s ) in loop B a t th e PORV s e t

C.46

p o in t p r e s s u r e (2450 p s i a ) . Loop A HPI flow th o ro u g h ly mixes i n the co ld

l e g . Loop B HPI i s n o t mixed because o f s t a g n a t io n . At 1500 s th e tem­

p e r a t u r e i s 134®F a t the loop B HPI i n j e c t i o n p o in t s and 207°F a t th e loop

B c o ld le g n o z z le s a t the v e s s e l . Both te m p era tu re s a re d e c l in in g a t a

r a t e o f 0 .23 ° F /s because c o n t in u e d HPI flow mixing w ith the c o o la n t in th e

c o ld l e g s , the g ra d u a l d isp la cem e n t o f w a te r from th e co ld l e g s , and f l u i d

h e a t in g by the p ip e w a l l s o f th e co ld l e g s . I f th e se t re n d s c o n t in u e , 50°p

( i . e . , the HPI i n j e c t i o n te m p e ra tu re ) w a te r would be enco u n te red a t 1860 s

and 2175 s a t th e se r e s p e c t iv e l o c a t i o n s o f loop B. ( 4 ) . The tu rb in e

bypass v a lv e a re a of 0 .1 6 f t as ta k e n from the LANL model was ha lv ed in

the c a l c u l a t i o n s to s im u la te f a i l u r e o f o n ly one TBV in th e bank. ( 5 ) . In

some c a s e s , a q u a s i - s t a t i c te m p e ra tu re was c a l c u l a t e d a t 1500 s to p ro v id e

a p o in t f o r l i n e a r e x t r a p o l a t i o n to a r e g io n where the cooldown model cou ld

be e a s i l y a p p l i e d . The q u a s i - s t a t i c te m p e ra tu re c a l c u l a t i o n assumes t h a t

the energy lo s s r a t e in th e steam le a v in g th e s tuck -open TBV eq u a ls the

decay h e a t r a t e . A un ique steam g e n e r a to r tem p era tu re i s o b ta in e d f o r t h i s

q u a s i - s t a t i c ene rgy b a la n c e . The downcomer te m p era tu re i s o b ta in e d from a

m ixing c a l c u l a t i o n c o n s id e r in g t h i s steam g e n e ra to r c o n d i t io n and HPI and

v e n t v a lv e flow r a t e s and te m p e ra tu re s .

Two-Loop TBV F a i l u r e — To app ly the cooldown model to the tw o-loop TBV

f a i l u r e , th e fo l lo w in g in fo rm a t io n from LANL case 6A, 6B and assum ptions

a re r e q u i r e d : ( 1 ) . Balanced loop n a t u r a l c i r c u l a t i o n f low s o f 842 l b / s fo r

each loop a re assumed to p e r s i s t to 7200 s . ( 2 ) . Vent v a lv e v e l o c i t i e s

a f t e r 250 s approach v a lu e s c o r re sp o n d in g to 44 I b / s (20 k g / s ) . I t i s

assumed t h a t t h i s v a lue h o ld s to 7200s. ( 3 ) . D n th ro t t l e d HPI flow s t o t a l

40 I b / s (18 k g /s ) in loop A and 30 I b / s (14 k g /s ) in loop B a t th e PORV s e t

C.47

p o in t p r e s s u r e . ( 4 ) . The tu r b in e bypass v a lve a re a of 0.16 f t from

th e LANL model vas h a lv e d in th e c a l c u l a t i o n s to s im u la te f a i l u r e of only

one TBV p e r loop . ( 5 ) . Where a p p l i c a b l e , th e q u a s i - s t a t i c te m p era tu re

(a s d is c u s s e d above) i s used f o r e x t r a p o l a t i o n o f th e i n i t i a l 1500 s of

a sequence .

b . P r e s s u re

P r e s s u r e i s de te rm ined on a c a s e -b y -c a se b a s i s and w i l l depend on i n t i a l

cooldown mechanism. R e p r e s s u r i z a t io n r a t e s observed in LANL c a se s 5A, 5B,

and SC and 6A, 6B. and 60 a re a p p l ie d as e n g in e e r in g judgment s u g g e s ts .

c . Heat T r a n s f e r C o e f f i c i e n t

Heat t r a n s f e r c o e f f i c i e n t s a r e p r i m a r i l y a f u n c t io n o f f l u i d v e l o c i t y . Four

reg im es e x i t i n th e s tudy c a s e s : fo u r RCPs o p e r a t in g , n a t u r a l c i r c u l a t i o n

(tw o - lo o p IBV f a i l u r e ) , n a t u r a l c i r c u l a t i o n w ith one loop s ta g n a n t (one-

loop IBV f a i l u r e ) , and two RCPs (one p e r loop) o p e r a t in g . LANL e s t ia ia te d

2 2 oh e a t t r a n s f e r c o e f f i c i e n t s o f 16000 W/m K (2820 B tu /h f t F) f o r fo u r -

RCP o p e r a t io n , 1200 W/m^K (210 B tu /h f t^ ° F ) f o r b o th n a t u r a l c i r c u l a t i o nfy

c a s e s , and 7500 W/m E (1320 B tu /h f t F) f o r the v e s s e l c e l l s r e c e iv in g

f u l l flow ( a l s o th e c o o l e s t w a te r) from the o p e ra t in g RCP in 1 RCP/loop

o p e r a t io n . These v a lu e s a re a p p l ie d as th e t r a n s i e n t sequence d i c t a t e s .

C.48

c . 4 . 2 Group 1 — Cases TBVl, TBV2, and TBV9

a. Tem perature

PIS concerns w i l l be most e v id e n t l a t e in th e se t r a n s i e n t s . Main

feed w ate r d i s tu r b a n c e s e a r l y in th e se sequences w i l l no t g r e a t l y in f lu e n c e

f i n a l te m p e ra tu re a l th o u g h e a r l y cooldown s lo p e s w i l l be d i f f e r e n t . The

te m p era tu re curve ( f i l e TBVGl.T) was c o n s t r u c te d u s in g the f i r s t 60 s of

LANL case 5B ( v a l i d to t h a t p o i n t ) , s t r a i g h t - l i n e e x t r a p o la t io n to the

q u a s i - s t a t i c te m p e ra tu re o f 366^F a t 1500 s , and fo llow ed by e x t r a p o la t i n g

w i th th e cooldown model t o 297°F a t 7200 s ( see Table C.9 and F ig u re C .9 ) .

Because of s ta g n a te d c o n d i t io n s in loop B, lo c a l tem p era tu res may be

d e p re s se d because o f th e absence of o th e r flow to mix w ith HPI. This

e f f e c t was e s t im a te d u s in g d a ta from th e cooldown model to c a l c u l a t e the

te m p era tu re o b ta in e d from mixing th e loop B HPI flow (30 I b / s ) and one-

h a l f of the t o t a l v en t v a lv e flow (132 I b / s ) . A minimum te m p era tu re of

270^F was o b ta in e d a t 7200 s . T h is minimum should be reexamined should

v en t v a lv e flow be red u ce d , as much low er te m p era tu re s would r e s u l t (see

Table C.IO and F ig u re C.IO)

b . P r e s s u re

P re s s u re was ta k en to fo l lo w the same p r o f i l e as LANL case 5B. T h is i s

c o n s e r v a t iv e , s in c e th e low er cooldown r a t e s w i l l ex tend th e p e r io d o f time

b e fo re HPI comes on and reduce th e time f o r HPI to re c o v e r system p re s s u re

to th e PORV s e t p o i n t , 2430 p s i . As modeled, th e p r e s s u r e drops to 1500

p s i a a t 150 s and rem ains t h e r e u n t i l 320 s , a f t e r which th e p r e s s u re

r i s e s t o i t s f i n a l v a lu e , 2430 p s i a t 975 s . Case IBV9 w i l l e x h ib i t

C.49

Table C.9 Nominal P, T, and b profiles for 16V group 1

TBVGl • T TBVGl .P TBVGl .b

Time(s) T(F) Time(s) P (p s ia ) Time(s) H(Btu/b)(f t**2F )

0 .0 555 .0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

60 .0 552.0 150.0 1500.0 233.0 210.01500.0 366 .0 320.0 1500.0 7200.0 210.02500.0 352.6 710.0 2000.03500.0 339 .8 975.0 2430.04500.0 327 .6 7200.0 2430.05500.0 315 .86500.0 304.67200.0 297 .0

C.50

p s r f t T C F )TBVGt

2 6 0 0

2200

1 8 0 0

1 4 0 0

1 0 0 0

6 0 00 1 0 0 0 2 0 0 0 5 0 0 0 7 0 0 0

T I M E ( S E C )

F i g u r e C.9 N o m i n a l p r e s s u r e s and t e m p e r a t u r e s f o r TBVg r o u p 1 s e q u e n c e s .

C .51

Table C.IO P, T, and b profiles for stagnated loop sideof TBV group 1 sequences

TBVGIA .T TBVGIA .P TBVGIA .b

Time(s) T(F) Time(s) P (p s ia ) Time(s) H(Btu/b)(f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 6 0 .0 1740.0 183.0 2820.0

6 0 .0 552 .0 150.0 1500.0 233 .0 210 .01500.0 366 .0 320.0 1500.0 7200.0 210.02500.0 346.5 710.0 2000.03500.0 328.3 975.0 2430.04500.0 311.2 7200.0 2430.05500.0 295.16500.0 280 .07200.0 270 .0

€.52

PSIF^ T C F )T B V G m

2 S 0 0 6 5 0

2 2 0 0 5 5 0

1 4 0 0 3 5 0

1 0 0 0 2 5 0

6 0 0 150.0 1000 20 00 4 0 0 0 7 0 0 0

TIMECSEC)

F i g u r e C.IO P r e s s u r e s and t e m p e r a t u r e s f o r s t a g n a t e d l o o ps i d e o f TBV g r o u p 1 s e q u e n c e s .

C .5 3

s l i g h t l y d i f f e r e n t b e h a v io r because o f PORV b lo c h v a lv e c l o s u r e . A f i n a l

p r e s s u r e o f 2500 p s i i s a t t a i n e d a t 1025 s when th e s a f e t y r e l i e f v a lv e s

a r e a c tu a te d . Note t h a t the h ig h e r p r e s s u r e would reduce HPI flow and

cooldown because o f t h a t flow (s e e T ab les C.9 and € .1 0 and F ig u re s C.9 and

C .IO ) .

o . Heat T r a n s f e r C o e f f i c i e n t

The h e a t t r a n s f e r c o e f f i c i e n t i s 2820 B tu /h f t F u n t i l th e RCPs t r i p a t2 ft

183 s . The c o e f f i c i e n t th e n d rops a t 210 B tu /h f t F f o r th e rem ainder

o f th e t r a n s i e n t ( s e e T ab les C.9 and C.IO)

C .4 .3 GROUP 2 — Cases TBV3 and TBV5

a . Tem perature

T h is group i s ta k e n to be i d e n t i c a l to TBVGl up th rough 22 min (1320 s)

when one RCP/loop i s r e s t a r t e d . SGB w i l l supp ly h e a t to the p r im ary to

r a i s e the downcomer te m p e ra tu re by an average o f lO^’P. Tem perature w i l l

l i n e a r l y d e c re a se to 328°F a t 2500 s as th e 6 0 ,0 0 0 - lb w a te r in v e n to ry in

SGA d r i e s o u t . Steam flow r e s t r i c t i o n may in c re a s e the d ry o u t p e r io d bu t

would a l s o r e s u l t in h ig h e r f i n a l te m p e ra tu r e s . A f te r steam g e n e r a to r A

d r y o u t , th e system w i l l r e h e a t a t 0 .0 4 8 9 ^ F /s t o re a c h 547^F a t 6980 s , and

i t would be l i m i t e d a t t h a t p o in t by au to m atic a c t i o n o f th e TBVs in steam

g e n e ra to r B ( s e e Table C . l l and F ig u re C . l l ) .

C.54

b . P re s sn re

Tbe p r e s s u r e curve of TBV group 1 (F ig u re C.9) was used to 1320 s . System

sh r in k ag e due to in c re a s e d h e a t t r a n s f e r caused p r e s s u r e d ec re ase on the

o rd e r of 500 p s i a t th e s t a r t u p of the RCPs in LANL case SC. F u r th e r

d rops were c o n t r o l l e d by HPI i n j e c t i o n . S im i la r b e h a v io r i s assumed h e re ,

r e s u l t i n g in a p r e s s u r e change from 2430 p s i a t 1320 s to 1930 p s i a t

1450 s t h a t w i l l c o n t in u e a t t h i s va lue u n t i l SGA dryou t a t 2500 s . Then

p r e s s u r e i s assumed to in c re a s e a t 0 .34 p s i / s (ob se rv ed va lue in LANL MSLB

base case) because of system r e h e a t in g u n t i l reac h in g PORV s e t p o in t 2430

p s i a t 3950 s ( s e e Table C . l l and F ig u re C . l l ) .

c . Heat T r a n s f e r C o e f f i c i e n t

H eat t r a n s f e r i s th e same as fo r TBV group 1 t o 1320 s . With 1 RCP/loop

2 Aflow e s t a b l i s h e d , th e h e a t t r a n s f e r c o e f f i c i e n t becomes 1320 B tu /h f t F

th rough the rem ainder o f th e t r a n s i e n t ( s e e Table C . l l )

C .4 .4 Group 3 — Cases TBV4 and TBV6

a. Tem perature

The m assive HFW o v e r fe e d s in th e se s c e n a r io s w i l l cause the t r a n s i e n t s to

c l o s e l y resem ble LANL c a se s 5A and 5B to 1320 s (372°F) when 1 RCP/loop

i s r e s t a r t e d a f t e r fee d w a te r i s o l a t i o n . A w a te r in v e n to ry of 140.000 lb

i s p r e d i c t e d by LANL c a se s 5A and 5B a t t h i s p o in t in the t r a n s i e n t . The

te m p e ra tu re would th e n d e c re a se to 407°F a t 3520 s when the 1 4 0 ,0 0 0 - lb

w a te r in v e n to ry of SGA i s f i n a l l y e x h au s te d . The system w i l l th en r e h e a t

a t 0 .0 4 8 9 ^F /sec u n t i l re a c h in g 547^F a t 6380 s . Steam v e n t in g by the

C.55

Table C.ll P, T, and h profiles for TBV group 2 sequences

TBVG2 .T TBVG2 .? TBVG2 .b

Tiaie(s) T(F) Tis>e( s) P ( p s i a ) Time(s) H (Btu/b)( f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

6 0 .0 552.0 150.0 1500.0 233 .0 210 .01320.0 389.3 320.0 1500.0 1320.0 210 .01321.0 409.3 710.0 2000.0 1321.0 1320.02500.0 328 .0 975.0 2430.0 7200.0 1320.069 80.0 547.0 1320.0 2430.07200.0 547.0 1450.0 1930.0

2500.0 1930.03950.0 2430.07200.0 2430.0

C.56

PSIf l T ( F)TBVG2

6 0 0 £50.

1 4 0 0 3 5 0

1 0 0 0 2 5 0

6 0 0 1500 1000 3 0 0 0 5 0 0 0 7 0 0 0

TIMECSEC)

F i g u r e C . l l P r e s s u r e s an d t e m p e r a t u r e s f o r TBV g r o u p 2 s e q u e n c e s .

C.57

SGB tu r b i n e bypass v a lv e s w i l l keep tb e system a t t b i s te m p e ra tu re f o r tbe

rem ainder o f tb e t r a n s i e n t ( see Table C.12 and F ig u re C .1 2 ) .

b . P r e s s u re

Tbe p r e s s u r e w i l l fo l low a s i m i l a r t r e n d as t b a t of TBV group 2 excep t

t b a t r e p r e s s u r i z a t i o n a f t e r RCP s t a r t u p w i l l be de layed to 3520 s and f i n a l

system p r e s s u r e , 2430 p s i , i s r e g a in e d a t 4970 s (see Table C.12 and F ig u re

C .1 2 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

T bis case i s e x a c t ly tbe same as TBV group 2 ( s e e Table C12).

C .4 .5 Group 4 — Case TBV7

a. T em perature

Because of tb e m assive o v e rfeed o f co o l w a te r to bo tb SGs, s a t u r a t e d b e a t

t r a n s f e r c o n d i t io n s a re no t expec ted and tb e case w i l l c l o s e l y resem ble

LANL case 5A, wbicb i s dominated by a s u s t a in e d main and emergency feedw ater

o v e r fe e d tb ro u g b mucb of tb e sequence . Tbe LANL-supplied v a lu e s f o r LANL

case 5A, in c lu d in g e x t r a p o l a t i o n to 7200 s , were a p p l ie d to t b i s case (see

Table C.13 and F ig u re C .1 3 ) .

I f tb e HW/CB pump system does n o t s u s t a i n flow to tbe d e p r e s s u r iz e d SGA,

tbe open TBV would in s t e a d c o n t r o l tb e cooldown r a t e . However, b ig b e r

te m p e ra tu re s ( t . = 300^F a t 7200 s) would r e s u l t ,min

C.58

# Table C.12 P, T, and b profiles for JBV group 3 sequences

TBVG3 .T TBVG3 .? TBVG3 .h

Time( s ) T(F) Tim e(s) P (p s ia ) Time(s) H( B tu /h ) (f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

6 0 .0 552.0 150.0 1500.0 233.0 210.0158 .0 531.0 320 .0 1500.0 1320.0 210.0316 .0 470.0 710 .0 2000.0 1321.0 1320.0552.0 422 .0 975.0 2430.0 7200.0 1320.0

1030.0 387 .0 1320.0 2430.01320.0 372.0 1450.0 1930.01321.0 433.0 3520.0 1930.03520.0 407.0 4970.0 2430.06380.0 547.0 7200.0 2430.07200.0 547.0

C.59

P S I f t T ( F )TBVG3

2 6 0 0

2200

1 8 0 0

1 4 0 0

1000

6 0 06 0 0 0 7 0 0 00 1000 4 0 0 0

T I M E (S E C )

F i g u r e C.12 P r e s s u r e s and t e m p e r a t u r e s f o r TBV group 3 s e q u e n c e s .

C.60

Table C.13 P, T, and h profiles for TBV group 4 sequences

TBVG4 .T TBVG4 .? TBVG4 .b

Time(s) T(F) Time(s) P (p s ia ) Time(s) H(Btu/h)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

60 .0 552.0 150.0 1500.0 233.0 210.0158 .0 531.0 400.0 1500.0 7200.0 210.0316 .0 470 .0 600 .0 1750.0552.0 422 .0 1036.0 2430.0

1030.0 387 .0 7200.0 2430.01320.0 372 .01500.0 365 .07200.0 197.6

C.6 1

P S I f t TCP)TBVG4

5 6 0 0

2200

1 8 0 0

1 4 0 0

1000

6 0 05 0 0 0 7 0 0 00 1000 2000 4 0 0 0 6 0 0 0

TIMECSEC)

F i g u r e C .1 3 P r e s s u r e s an d t e m p e r a t u r e s f o r TBV g r o u p 4 s e q u e n c e s .

C .62

b . P r e s s a r e

LANL case SA as e x t r a p o la t e d was used f o r t b i s case ( see Table C.13 and

F ig u re C .1 3 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

This case i s i d e n t i c a l t o TBV group 1 ( s e e Table C .13 ) .

C .4 .6 Group 5 — Cases TBV8 and TBV16

a . T em perature

Group 5 fo l lo w s LANL c a se s 6A, 6B, and 6C th rough the f i r s t 60 s .

A f te rw a rd s , s t r a i g h t - l i n e e x t r a p o l a t i o n i s fo llow ed a t the q u a s i - s t a t i c

te m p e ra tu re o f 320°F a t 1500 s . The cooldown model i s fo llow ed to 265°F

a t 7200 8. N e i th e r loop s t a g n a t e s , so HPI mixing i s n o t seen as a problem

(s e e Table C.14 and F ig u re C.14)

b . P r e s s u r e

The p r e s s u r e i s assumed to drop to 1000 p s i a a t 200 s where HPI l i m i t s

f u r t h e r r e d u c t io n s . P r e s s u re rem ains f l a t ou t to 500 s and th e n in c re a s e s

to th e PORV s e t p o in t (2430 p s i a ) a t 1175 s . P r e s s u re rem ains a t PORV

l i m i t f o r th e rem ainder o f th e sequence ( s e e Table C.14 and F ig u re C .14 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

No d i s t i n c t i o n i s made between th e one- lo o p TBV f a i l u r e s and the tw o-loop

TBV f a i l u r e s . T h e re fo re , t h i s case i s i d e n t i c a l to TBV group 1 ( se e Table

C .1 4 ) .

C.63

Table C.14 P, T, and b profiles for TBV gronp 5 sequences

TBVG5 .T TBVG5 .? TBVG5 .b

Tiaie(s) T(F) Time(s) P (p s ia ) T in e ( s ) H(Btn/b)(f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 200.0 1000.0 183.0 2820.0

6 0 .0 552.0 500.0 1000.0 233 .0 210 .01500.0 320.0 1175.0 2430.0 7200.0 210.02500.0 309.4 7200.0 2430.03500.0 299.34500.0 289.55500.0 280.16500.0 271.07200.0 265.0

C .6 4

TBVG5

2 6 0 0

£200

1 8 0 0

1 4 0 0

1000

6 0 0 0 1000 2000 7 0 0 03 0 0 0 6 0 005 0 0 0

T I M E ( S E C )

F i g u r e C.14 P r e s s u r e s and t e m p e r a t u r e s f o r TBV group 5 s e q u e n c e s .

C .6 5

C.4.7 Group 6 -- Cases TBVIO, TBV13, and TBV15

a . T e n p e ra tu re

Tbese ca se s a re s i m i l a r to TBV group 1 to 975 s when the PORV a c tu a te s

and s t i c k s open. (TBV13 s p e c i f i e s f a i l u r e o f the PORV and a s a f e ty

r e l i e f v a lv e to c l o s e . Houever, th e SRV would n ever be c h a l le n g e d and

i s t h e r e f o r e no t assumed to f a i l . ) HPI flow in c re a s e s because o f reduced

p r im ary p r e s s u r e . The in c re a s e in flow w i l l cause HPI flow to dominate

o v e r steam flow th rough the open TBV as th e main h e a t removal mechanism

l a t e in th e sequence . Based on lo o p , HPI, and v en t v a lv e f low s from the

LANL PORV-LDCA case 2A and TBV a re a and c o n d i t io n s d e s c r ib e d in S e c t io n

C .4 , a minimum te m p era tu re of 257°F was o b ta in e d a t 7200 s u s in g the

cooldown model ( s e e Table C.15 and F ig u re € .1 5 ) .

b . P r e s s u r e

T h is group i s s i m i l a r to TBV group 1 to 975 s when the PORV i s f i r s t

a c t u a t e d . The p r e s s u r i z e r i s l i q u i d - s o l i d a t t h i s p o in t . F a i l u r e of

th e PORV to c lo se r e s u l t s in w a te r flow th rough the v a lve and a drop in

p r e s s u r e , which prom otes more flow . The p r e s s u r e d e c re a se s and th e flow

in c re a s e s u n t i l an e q u i l ib r iu m i s s t r u c k between PORV flow r e s i s t a n c e and

HPI head c a p a c i t y c h a r a c t e r i s t i c s . T h is e q u i l ib r iu m p o in t i s a t a system

p r e s s u r e o f 1670 p s i a , as o b ta in e d from LANL case 2A. No v o id in g i s

ex p ec ted as a r e s u l t o f t h i s d e p r e s s u r i z a t i o n . The system re a c h e s t h i s

f i n a l p r e s s u r e q u ic k ly (assume 25 s) and rem ains th e r e f o r th e r e s t o f the

t r a n s i e n t ( s e e T ab le € .15 and F ig u re € .1 5 ) .

€.66

Table C.15 P, T, and b profiles for TBV gronp 6 sequences

IBVG6 .T IBVG6 .? TBVG6 .h

Tim e(s) T(F) Tiaie(s) P ( p s i a ) Tiaie( s) H( B tu /h ) ( f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

6 0 .0 552.0 150.0 1500.0 233 .0 210.0975 .0 433.0 320.0 1500.0 7200.0 210.0

1500.0 373 .0 710 .0 2000.02500.0 335.1 975.0 2430.03500.0 308.7 1000.0 1670.04500.0 289.4 7200.0 1670.05500.0 274 .86500.0 263.67200.0 257 .0

C.67

PSIf l TCP)TBVGS

2 8 0 0

2200

1 8 0 0

1 4 0 0

1000

6 0 07 0 0 06 0 0 05 0 0 03 0 0 010000

T I M E ( S E C )

F i g u r e C .15 P r e s s u r e s a n d t e m p e r a t u r e s f o r TBV g r o u p 6 s e q u e n c e s ,

C .6 8

c . Heat T r a n s f e r C o e f f i c i e n t

T h is gronp i s i d e n t i c a l to f i l e TBV gronp 1 ( se e Table € .1 5 ) .

C .4 .8 Gronp 7 — Case TBV12

a. T esiperatnre

The coa ib ina tion o f a s in g l e TBV f a i l n r e and a s in g le steam s a f e ty r e l i e f

v a lv e on loop A makes gronp 7 s i m i l a r to a TBV bank f a i l n r e , as in LANL

cases SA, SB, and SC. However, th e p ro p e r o p e r a t io n o f the NFV system

von ld p re c ln d e th e sev e re o v e r fe e d in g l a t e in LANL cases SA, SB, and SC.

T h e re fo re , cooldown r a t e s c a l c n l a t e d from the expanded cooldown model were

nsed t o p r e d i c t th e system re s p o n s e . LANL case SA was nsed to 60 s (SS2°F).

E x t r a p o la t i o n by the cooldown model y ie ld e d a minimnm te m p era tn re of 272°F

a t 7200 s . T h is te m p e ra tn re re sp o n se i s v e ry s im i l a r to t h a t o f TBV gronp

S, which f e a t n r e s th e same t o t a l b re a k a re a a p p o r t io n e d between b o th lo o p s .

The main d i f f e r e n c e s betw een th e two gronps a re dne to d i f f e r e n t loop flow

and v e n t v a lv e flow r a t e s ( s e e Table C.16 and F ig n re C .1 6 ) .

b . P r e s s n r e

The gronp i s ta k e n to be i d e n t i c a l to TBV gronp 1 ( s e e Table C.16 and

F ig n re C .1 6 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

The gronp i s ta k e n to be i d e n t i c a l to TBV gronp 1 ( se e Table C .16 ) .

C.69

Table C.16 P, T, and b profiles for TBV gronp 7 sequences

TBVG7N ,T 1BVG7N.P TBVG7N.h

T io e ( s ) T(F) Tiaie(s) P ( p s i a ) Tim e(s) H (Btu/h)( f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

6 0 .0 552.0 150.0 1500.0 233.0 210.0400 .0 392 .9 320 .0 1500.0 7200.0 210.0500.0 386.2 710.0 2000.0600 .0 380 .0 975.0 2430.0700 .0 376.5 7200.0 2430.0800.0 371 .4900 .0 368.3

1000.0 364 .81500.0 353 .92500 .0 330.03500.0 311.54500.0 297.25500.0 286 .06500 .0 277.27200.0 272.2

C .7 0

PSri=f T ( F )TBVG7N

as 00

2200

1 8 0 0

1 4 0 0

1000

S 0 0 0 2000 3 0 0 0 7 0 0 05 0 0 0

T I M E (S E C )

F i g u r e C .1 6 P r e s s u r e s an d t e m p e r a t u r e s f o r TBV g r o u p 7 s e q u e n c e s .

C .7 1

c . 4 .9 Group 8 — Case TBVll

a . Tem perature

T h is group d i f f e r s from IBV group 7 in t h a t th e fe e d w a te r i s i s o l a t e d a t

20 min and 1 RCP/loop i s r e s t a r t e d a t 22 min (1320 s ) . T h e re fo re , the

case u se s th e e x t r a p o l a t i o n f o r IBV group 7 ou t t o 1320 s . The r e s t a r t

o f th e RCPs cau ses m ixing o f ho t w a te r from SGB w ith th e o th e r w a te r in the

system to r a i s e th e downcomer te m p era tu re to 433°F. Flow choking l i m i t s

th e steam lo s s r a t e in SGA to about 100 I b / s . SGA d ry o u t i s accom plished

a t 1820 s , a t which time system te m p e ra tu re i s 423°F , th e l e v e l n e c e ssa ry

to m a in ta in th e steam lo s s r a t e in SGA. A f te r SGA d ry o u t , th e system

r e h e a t s a t 0.0489*^F/s t o re a c h 547°F a t 4360 s , where i t rem ains f o r the

r e s t o f the sequence (s e e Table C.17 and F ig u re C .1 7 ) .

b . P r e s s u re

This case i s ta k e n to be i d e n t i c a l t o TBV group 3 t o 1450 s . The p r e s s u re

to t h i s p o in t has f a l l e n from 2180 to 1500 p s i a a t 150 s , r i s e n to 2430

p s i a a t 975 s , and dropped to 1930 p s i a a t 1450 s because of mixing of

h o t and coo l l i q u i d s in th e p r im ary a f t e r RCP s t a r t u p . The p r e s s u r e i s

assumed c o n s ta n t t o 1820 s and th e n in c r e a s e s a t 0 .3446 p s i / s to 2430 p s i a

a t 3270 s , where i t rem ains f o r th e r e s t of th e sequence ( see Table C.17

and F ig u re C .1 7 ) .

c . Heat T ra n s f e r C o e f f i c i e n t

T h is group i s ta k e n to be i d e n t i c a l to TBV group 2 ( s e e Table C .1 7 ) .

C.72

Table C.17 P, T, and h profiles for TBV group 8 sequences

TBVGS .T TBVGS .P TBVGS .b

Tim e(s) T(F) Tim e(s) P (p s ia ) Time( s) H(Btu/b)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1740.0 183.0 2820.0

6 0 .0 552.0 150.0 1500.0 233.0 210.01320.0 348.7 320.0 1500.0 1320.0 210.01321.0 433.0 710 .0 2000.0 1321.0 1320.01820.0 423.0 975.0 2430.0 7200.0 1320.04360.0 547.0 1320.0 2430.07200.0 547.0 1450.0 1930.0

1820.0 1930.03270.0 2430.07200.0 2430.0

C.73

P S I f t TCF)TBVG3

2S00

2200

1 3 0 0

1 4 0 0

1000

6 0 00 1000 3 0 0 0 5 0 0 0 7000 .6 0 0 0

TIMECSCCl

F i g u r e C .17 P r e s s u r e s a n d t e m p e r a t u r e s f o r TBV g r o u p 8 s e q u e n c e s .

C.74

c . 4 .10 Group 9 — Case TBV17

a . T e n p e ra tu re

V ith tlie MFl o v e r fe e d and subsequen t f lo o d in g o f SGA w ith flow f ro o tbe

HW/CB punps v ia the s t a r t u p flow c o n t r o l v a lv e s , th e case should c l o s e l y

resem ble LANL case 5B. A f te r SGA i s co m p le te ly f u l l , feedw ate r w i l l flow

from the feed w a te r r in g to the SG o u t l e t w ith a sm all b u t undeterm ined

amount o f h e a t b e in g abso rbed from th e p r im a ry . For t h i s a n a l y s i s , i t i s

assumed t h a t t h i s fo l lo w s a s in g le loop TBV f a i l u r e response i d e n t i c a l to

LANL case SA, as e x t r a p o la t e d ( s e e Tab le C.18 and F ig u re C .1 8 ) .

b . P r e s s u re

This group i s assumed to be i d e n t i c a l t o TBV group 5 because of e a r l y

e f f e c t s o f system cooldown (s e e Table C.18 and F ig u re C .1 8 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

T his group i s ta k e n to be i d e n t i c a l to TBV group 1 ( s e e Table C .18 ) .

C .4 .11 Group 10 — Cases TBV18 and TBV19

a . Tem perature

T h is group in c lu d e s the e q u iv a le n t o f s in g l e TBV f a i l u r e s in each loop

and a POKV-sized LO(A. The case i s s i m i l a r to TBV group 6 excep t t h a t

b o th loops a re a f f e c t e d . LANL case 5A was used t o 60 s (SST^^F), th e n the

cooldown model was used t o e x t r a p o la t e t o a minimnm te m p era tu re o f 2 3 6 .7^F

a t 7200 s ( s e e Table C.19 and F ig u re C .1 9 ) .

C.75

Table C.18 P , T. and h p r o f i l e s f o r TBV gronp 9 sequences

XBVG9 .T TBVG9 .P TBVG9 .h

Time(s) T(F) Time(s) P (p s ia ) T ime(s) H(Btu/h)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 200.0 1000.0 183.0 2820.0

60 .0 552.0 500.0 1000.0 233.0 210.0158 .0 531.0 1175.0 2430.0 7200.0 210.0316 .0 470.0 7200.0 2430.0552.0 422.0

1030.0 387 .01320.0 372.01500.0 365 .07200.0 197.6

c .16

psrfl- TCF) TBVG9L600

2 2 0 0

1 8 0 0

1 4 0 0

1 0 0 0

8 0 00 d 000 5 0 0 0

TIME(SEC)

F i g u r e C .1 8 P r e s s u r e s an d t e m p e r a t u r e s f o r TBV g r o u p 9 s e q u e n c e s .

C .7 7

T able C.19 P. T. and b p r o f i l e s f o r TBV group 10 sequences

TBVGIO.T TBVGIO .P TBVGIO .b

Tim e(s) T(F) TiaieCs) P (p s ia ) Tiaie(s) H (Btu/b)(f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 200.0 1000.0 183.0 2820.0

6 0 .0 552.0 500.0 1000.0 233 .0 210 .01500.0 331.1 1175.0 2430.0 7200.0 210.02500.0 296.6 1200.0 1670.03500 .0 275.2 7200.0 1670.04500.0 260.45500.0 249 .56500.0 241.37200.0 236.7

C.78

PSIR TCF) TBVG10

2 6 0 0

2 2 0 0

1 8 0 0

1 4 0 0

1000

6 0 0 1000 7 0 0 06 0 00TIME(SEC)

F i g u r e C.19 P r e s s u r e s an d t e m p e r a t u r e s f o r TBV g r o u p 10 s e q u e n c e s .

C.79

b . P r e s s u re

T h is group r e s e n b le s TBV group 5 ou t t o 1175 s . The p r e s s u r e bas dropped

from 2180 p s i a to 1000 p s i a a t 200 s under the in f lu e n c e o f o v e rco o l in g

b o th lo o p s . At 500 s , p r e s s u r e b e g in s to in c re a s e from 1000 p s i a to 2430

p s i a a t 1175 s . PORV s t i c k s open a t t h i s p o i n t , and p r e s s u r e d rops to

1670 p s i a a t 1200 s as HPI flow in c re a s e s t o s u s t a i n p r e s s u r e a t t h i s l e v e l

f o r the rem a inder o f th e sequence ( s e e Table C.19 and F ig u re C .19 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

T h is group i s i d e n t i c a l to TBV group 1 ( s e e Table C .1 9 ) .

C.80

c .5 T u rb ine B y p x t Valve Fn i l n r e s in H ot,S tandby

O vercoo ling e v e n ts a t h o t s tandby can y i e l d sev e re cooldown r a t e s because

o f th e absence of s i g n i f i c a n t decay h e a t in p u t to th e system. INEL

perform ed a c a l c u l a t i o n o f a sequence where a l l fo u r IBVs f a i l open

(because o f a c o n t ro l - s y s te m f a u l t ) and a re i s o l a t e d 10 min l a t e r . ORNL

s p e c i f i e d c a se s where one TBV and two TBVs in one loop f a i l open w ithou t

su bsequen t i s o l a t i o n o f th e TBV(s) o r t h r o t t l i n g o f HPI. To i n v e s t i g a t e

th e s e n s i t i v i t y of th e sequences to decay h e a t l e v e l , decay h e a t r a t e s

c o r re sp o n d in g t o 12 h and 1 wk r e s p e c t i v e l y s in c e shutdown from f u l l power.

Table C.20 d e s c r ib e s th e sequences . The cooldown model p r e d ic te d very

r a p id cooldown r a t e s , l a r g e l y because o f poor acco u n tin g of p ipe and v e s s e l

w a l l - t o - w a t e r h e a t t r a n s f e r . The e r r o r i s l e s s pronounced f o r t r a n s i e n t s

from f u l l power where decay h e a t - in d u c e d n a t u r a l c i r c u l a t i o n and ven t v a lve

f low s swamp any m e ta l - t o - w a te r h e a t in g e f f e c t s .

C .S . l B as is

INEL — 4TBV f a i l u r e a t h o t s tan d b y .

C .S .2 D e p a r tu re s from B a s is

a . One- and two-TBV f a i l u r e s were e v a lu a te d .

b . TBVs in b ase case were i s o l a t e d a t 10 min.

Study ca se s have no TBV i s o l a t i o n .

C .8 1

Table C.20 Hot standby TBV failure cases

C o n d it io n s

ZP ITBV

(12 h)

ZP 2TBV

(12 h)

Case

ZW IIBV

(1 wk)

ZW 2TBV

(1 wk)

Hot s tandby z X X X

Decay h e a t l e v e l s

a . 12 h r = 15.75 MW X X

b . 1 wk = 7 .5 MW X X

Cspi£Ol

1 IBV opens SGA X X

2 TBVs open SGA X X

SGB TBVs o p e ra te as d es igned X X X X

SSKVs o p e r a te as d e s ig n ed X X X X

F eedw ate r Suunlv

Feedw ater c o n t r o l l e d to X X X X*

a p p r o p r ia t e l e v e l

Poptiro i

PORV o p e r a te s as des ig n ed X X X X

O u era to r A c tio n s

RCPs t r i p p e d a t HPI + 30 s X X X X

Assumes post-RCP t r i p SG l e v e l m a in ta in e d by w hatever feed w a te r source a v a i l a b l e

C.8 2

C .5 .3 A p p lic a b le Data from O tber Cases

None.

C .S .4 E x t r a p o la t io n A ssum ptions. P ro c e d u re s , and R e s u l t s

a . T em perature

The cooldown model was employed to e v a lu a te s i n g l e - and double-TBV

f a i l u r e s a t h o t s ta n d b y . T o ta l loop flows o f 40 ,000 I b / s were used

p r i o r t o RCP t r i p , and a t o t a l n a t u r a l c i r c u l a t i o n r a t e of 700 I b / s

was used in l a t e r s ta g e s o f th e t r a n s i e n t s . These v a lu e s were o b ta in e d

from th e INEL base case c a l c u l a t i o n . Two power l e v e l s were examined.

The f i r s t l e v e l used a c o n s ta n t r e s i d u a l decay h e a t of 15 .7 MW,

c o rre sp o n d in g to about 12-14 h a f t e r t r i p from fu l l -p o w e r o p e ra t io n .

The second l e v e l used a v a lu e o f 8 .5 NW, co rresp o n d in g to a shutdown

p e r io d o f 1 wk. A sm all v en t v a lv e flow of 45 I b / s was ta k en from

th e LANL PORV LOCA c a s e . I n i t i a l p r im ary te m p era tu re s o f 548°F and

fe e d w a te r te m p e ra tu re s o f 90°F were assumed f o r bo th th e NFV and EFV

s y s te m s .

For one IBV f a i l u r e a t 12 h a f t e r shutdown, downcomer te m p era tu re

d e c re a s e s to 498^F a t 250 s when HPI comes on, t o 328°F a t 480 s when

SG f i l l s to 20 f t o f w a te r a f t e r RCP t r i p i s com pleted , and th en to

303°F a t 1000 s when th e p r im ary system goes w a t e r - s o l i d and HPI flow

d e c r e a s e s . The downcomer te m p e ra tu re r i s e s t o 307^F a t 1500 s because

o f th e HPI flow d e c re a se r e l a t i v e to the warmer loop f lo w s , bu t then

i t resumes d e c l in e , r e a c h in g 300°F a t 2000 s and 234*^F a t 7200 s ( see

T ab le C.21 and F ig u re C .2 0 ) .

C.83

T ab le C.21 P> T, and b p r o f i l e s (12 h a f t e r shntdovn)

f o r 1 TBV f a i l u r e a t h o t s tandby

ZPITBV.T ZPITBV.P ZPlTBV.h

Tim e(s) T(F) Tim e(s) P (p s ia ) Time(s) H (Btu/h)(f t* * 2 F )

0 .0 548.0 0 .0 2180.0 0 .0 2820.0150 .0 513.1 250 .0 1500.0 280.0 2820.0250 .0 497.6 700 .0 1500.0 330 .0 300.0280 .0 490.3 1000.0 2430.0 2000.0 300.0480 .0 328.0 7200.0 2430.0 7200.0 147.0

1000.0 302.81500.0 306.82000.0 299.72500.0 285.63000.0 276.94000.0 262.65000.0 251.56000.0 242.67200.0 234.3

C.8A

PSIft T(.F)Z P IT B V

PC6 0 0

2200

1 8 0 0

1 4 0 0

1000

6 005 0 0 010000

TIMECSEC)

F i g u r e C.20 P r e s s u r e s and t e m p e r a t u r e s f o r 1 TBV f a i l u r e a t h o t s t a n d b y (12 h r s . a f t e r shu tdow n) .

C.85

For one IBV f a i l e d open 1 vk a f t e r skntdown, te m p e ra tn re d e c re a se s

t o 501°F a t 200 s when HPI comes on, t o 327*^F a t 460 s when th e

SGs f i l l to 20 f t of w a te r a f t e r RCP t r i p , and th e n to 298^F a t

1000 s when th e p r im ary goes w a t e r - s o l i d and HPI flow d e c r e a s e s . The

downcomer te m p e ra tn re r i s e s t o 300°F a t 1500 s hecanse of reduced HPI

flow ( te m p e ra tu re d i l u t i o n ) , h u t th e n i t resumes d e c l in e as th e system

cooldown o v e r ta k e s the HPI mixing as th e dominant mechanism. The

downcomer te m p e ra tu re d rops t o 2 8 6 .4^F a t 2000 s and 2 0 7 .2°F a t 7200

s . The d i f f e r e n c e in decay h e a t in p u t i s most n o t i c e a b l e l a t e in th e

sequence (s e e Tab le C.22 and F ig u re C .2 1 ) .

With two TBVs f a i l open 12 h a f t e r shutdown, te m p e ra tu re d e c l in e s to

490°F a t 120 s when th e HPI comes on, to 303**F a t 350 s when SGs f i l l

t o 20 f t o f w a te r a f t e r RCP t r i p i s com ple te , and to 277^F a t 900 s

when th e p r im ary system goes w a t e r - s o l i d . The downcomer te m p era tu re i s

assumed t o s ta y e s s e n t i a l l y c o n s ta n t to 1500 s in re sponse to reduced

HPI flow . Then te m p e ra tu re d e c l in e resum es, and a f i n a l v a lu e o f 209^F

i s reac h ed a t 7200 s ( s e e Table C.23 and F ig u re C .2 2 ) .

For two IBVs f a i l e d open 1 wk a f t e r shutdown, te m p e ra tu re d e c l in e s

t o 4 8 6 .8°F a t 120 s when SG f i l l i s com pleted a f t e r RCP t r i p and

t o 269°F a t 1000 s when th e p rim ary goes w a t e r - s o l i d and HPI flow s

d e c r e a s e . T em perature rem ains r e l a t i v e l y c o n s ta n t to 1500 s because

o f th e r e d u c t io n in HPI flow . Then the te m p e ra tu re d e c l in e resum es,

w ith a f i n a l v a lu e of 185°F reached a t 7200 s . A gain , th e d i f f e r e n c e

in decay in p u t i s o n ly d i s c e r n a b le l a t e in th e sequence ( s e e Table C.24

and F ig u re C .2 3 ) .

C .8 6

Table C.22 P. T. and h profiles for 1 TBV failure at hot standby(1 vk after shutdown)

ZWITBV.T ZWITBV.P ZWlTBV.h

Time(s) T(F) Time(s) P (p s ia ) Time(s) H(Btu/h)(f t**2F)

0 .0 548.0 0 .0 2180.0 0 .0 2820.050 .0 530.1 230 .0 1500.0 260.0 2820.0

100.0 518.4 700 .0 1500.0 310.0 300.0200 .0 501.2 1000.0 2430.0 2000.0 300.0230 .0 496.7 7200.0 2430.0 7200.0 147.0260 .0 488.4360 .0 346.6460 .0 327.6600 .0 319.3800.0 308.5

1000.0 298.71500.0 300.02000.0 286.42500 .0 274.43000.0 263.73500.0 254.24000.0 245.74500.0 238.05000.0 231.15500.0 224.86000.0 219.06500.0 213.87000.0 209.07200.0 207.2

C.87

P S I R TCP)ZW1TBV

2 6 0 0

2200

1 3 0 0

1 4 0 0

I 0 0 0

6 0 07 0 0 06 0 0 04 0 0 0 5 0 0 00 1000

TIMECSEC)

F i g u r e C.21 P r e s s u r e s and t e m p e r a t u r e s f o r 1 TBV f a i l u r e a t ho t s t a n d b y (1 wk a f t e r s h u t d o w n ) .

C.88

Table C.23 P, T, and h profiles for 2-TBV failure at bot standby(12 b after sbntdovn)

ZP2TBV.T ZP2TBV.P ZP2TBV.b

Time(s) T(F) Time(s) P ( p s i a ) Time(s) H(Btu/b)(f t* * 2 F )

0 .0 548.0 0 .0 2180.0 0 .0 2820.0120 .0 490.7 120.0 1500.0 150.0 2820.0150 .0 478.5 600.0 1500.0 200.0 300.0350 .0 303.1 900.0 2430.0 2000.0 300.0900.0 276.7 7200.0 2430.0 7200.0 147.0

1500.0 275 .82000.0 264 .52500.0 255 .03000.0 246.74000.0 233.55000.0 223.4dOOO.O 215.87200.0 208.7

C.89

P S l P t T(F) ZP2TBV

2 6 0 0

2200

1 8 0 0

1 4 0 0

1000

6 0 06 0 0 0 7 0 0 02 0 0 00 1000 3 0 0 0

TIMECSEC)

F i g u r e C .2 2 P r e s s u r e s and t e m p e r a t u r e s f o r 2 TBV f a i l u r e a t h o ts t a n d b y ( 1 2 h r s . a f t e r s h u t d o w n ) .

C .90

Table C.24 P(1

, T, and b p r o f i l e s f o r 2 - TBV wk a f t e r shutdown)

f a i l u r e a t ho t standby

ZW2TBV.T ZW2TBV.P ZW2TBV.h

T ia e ( s ) T(F) Tim e(s) P (p s ia ) Time(s) H(Btu/h) (f t**2F )

0 .0 548.0 0 .0 2180.0 0 .0 2820.060 .0 507.1 120 .0 1500.0 150.0 2820.0

120.0 486 .8 700 .0 1500.0 200.0 300.0150.0 474.5 1000.0 2430.0 2000.0 300 .0200.0 328 .9 7200.0 2430.0 7200.0 147.0250.0 319.5300 .0 310.7350.0 302.6500.0 293 .9700 .0 283.1850.0 275 .9

1000.0 269.21500.0 268 .92000.0 256 .02500.0 244.73000.0 234 .83500.0 226 .24000.0 218 .54500.0 211.65000.0 205.55500.0 200 .06000.0 195.16500.0 190.77000.0 186.67200.0 185 .0

C .9 1

psrfl TCP) ZW2TBV

2 6 0 0

2200

1 3 0 0

1 4 0 0

1000

6 0 07 0 0 03 0 0 0 4 0 0 020000 1 0 0 0

TIMECSEC)

F i g u r e C.23 P r e s s u r e s and t e m p e r a t u r e s f o r 2 TBV f a i l u r e a t h o t s t a n d b y (1 wk a f t e r s h u t d o w n ) .

C.92

N ln ia iw t e a p e r s t u r e s lo v e r th an the b ase case were o b ta in e d f o r th e se

s tu d y c a se s because the TBVs v e re no t i s o l a t e d a t 600 s , as in the

INEL base c a s e .

b . P r e s s u re

The time to reac h HPI s e t p o in t was assumed to be a f u n c t io n of average

c o o la n t te m p e ra tu re . However, th e a c t i o n o f p r e s s u r i z e r h e a t e r s and

m akeup/le tdow n system s g r e a t l y c o m p lic a te s th e s i t u a t i o n . S t a r t i n g

from h o t s tandby c o n d i t i o n s , th e p r e s s u r i z e r should empty when the

average te m p e ra tu re d rops below SOO ’f . I t i s assumed t h a t the p r e s s u r e

i s n e a r the HPI s e t p o in t when th e p r e s s u r i z e r em p tie s . With one TBV

open, th e system d e p r e s s u r i z e s ( c o o ls ) to th e HPI s e t p o in t (1500 p s ia )

a t 230 s (1-wk shutdown) o r 250 s (12 -h shutdow n). HPI i s assumed

to m a in ta in p r e s s u r e a t t h i s l e v e l u n t i l 700 s , whereon p r e s s u r e b eg in s

t o r i s e to the PORV s e t p o i n t , 2 4 3 0 p s i , a t 1000 s where i t rem ains

th ro u g h o u t th e sequence ( s e e T ab les C.21 and € .22 and F ig u re s € .20 and

€ . 21) .

With two TBVs open, th e system re a c h e s HPI s e t p o in t a t 120 s ( s i m i l a r

to base c a s e ) . I n s t e a d o f d e c re a s in g f u r t h e r , i t i s assumed t h a t

p r e s s u r e rem ains a t 1500 p s i a u n t i l 600 s (12-h shutdown) o r 700 s (1 -

wk shutdow n), when i t b e g in s to r i s e to i t s f i n a l v a lue o f 2430 p s i a

a t 900 s (12 -h shutdown) o r 1000 s (1-wk shutdow n). (See T ab les €.23

and €.24 and Figures €.22 and €.23.)

C .9 3

c . Heat T r a n s f e r C o e f f i c i e n t

fS _For b o th c a s e s , an i n i t i a l v a lu e o f 2820 ( B t u / h / f t F) was a p p l ie d

from th e LANL c a l c n l a t i o n s . A f te r RCP t r i p , INEL g iv e s v a lu e s o f 300

( B tu / h / f t ^ ° F ) t o 2000 8, which th e n d e c re a se to 147 (B tu/h/ft^*^F) a t

7200 s . T h is type o f g ra d u a l d e c re a se was expec ted b u t n o t observed

in any o th e r sequences . No c o r r e c t i o n f o r f r e e c o n v e c t io n e f f e c t s i s

in c lu d e d in th e s e v a lu e s ( s e e T ab le s C.21 th ro u g h C .2 4 ) .

C.94

C.6 PORV-Sized LOCA Ca«es

C .6 .1 ORNl>Defined PORV-Sized LOCAs

ORNL d e f in e d n in e PORV-sized LOCA c a s e s . These were s o r te d in to f iv e

groups based on case s i a i l a r i t i e s . The c h a r a c t e r i s t i c s o f th e n in e cases

and t h e i r r e s p e c t iv e g roup ings a r e d i s p la y e d in Table C .25. The t r a n s i e n t s

a re e v a lu a te d by groups below.

€ . 6 .1 . 1 Bases

LANL PORV LOCA case 2A

LANL Rancho Seco-type t r a n s i e n t

LANL TBV f a i l u r e case 5B

C .b .1 .2 D ep a r tu re s from Bases

a . A l l c a se s have a FORV-sized b re a k , b u t not n e c e s s a r i l y a f a i l e d PORV.

L o c a t io n o f the b re a k in the p r e s s u r i z e r surge l i n e ( f o r exam ple),

r a t h e r th an a t th e top o f th e p r e s s u r i z e r , would change system response

s in c e th e system may n o t go w a t e r - s o l i d . However, a s tu ck -o p en PORV

o r an e q u iv a le n t b re a k a t the to p o f th e p r e s s u r i z e r would r e s u l t in

l a r g e r cum ula tive HPI f low s and hence g r e a t e r cooldown th an a s i m i l a r -

s i z e b re a k e lsew h ere .

b . F eedw ate r p e r t u r b a t i o n s such as normal runback , SGA o v e r fe e d s , and lo s s

o f MFV w ith EFW f a i l u r e a re examined. Normal runback i s no t covered

in any o f th e b a s e s .

C .95

Table C.2S PORV-sized LX)CA cases and groupings

C o n d itio n 1 2 3

Case SBLOCA-

4 5 6 7 8 9

Secondary P re s s u re C o n tro ls

O p era tes as d es ig n ed X X X X X X X X

2 TBVs f a i l open loop A X

MFW runback as d es ig n ed X X X

SGA runback f a i l u r e X X X

LOMFW a t tim e = 0 . 0 X X X

EFW o p e ra te s a s d es ig n ed X X X X X X X

EFW in manual X X

P rim ary P re s s u re C o n tro ls

PORV b lo c k y a ly e open X X X X X X X X X** ***

PORV o p e ra te s as d es ig n ed X X X X X X X X X• *

SRV f a i l s to r e s e a t X X X

OpsrwtOf A pfjpppRCP t r ip p e d a t HPI + 30 s X X X X X X X X X

F u l l EFW flow a f t e r SG d ry o n t X X

I s o l a t e s SGs a t 20 min X

Group nnatber (PSBG-) 1 2 3 2 4 5 1 2 3

«O th er c o n d i t io n s common to a l l c a s e s ; f u l l power* decay h e a t 1 .0 tim esANS, a l l ECCS com ponents o p e ra te as d es ig n ed

«*I f c h a lle n g e d

B reak i s POBV-sized and may o ccu r anywhere

C.96

c . 6 . 1 .3 A p p lic a b le Data froat O ther Cases

The INEL 2 - i n . h o t le g and 2 . 5 - i n . c o ld le g LOCA cases show t r e n d s in

system p re s s u re * b re a k flows* downcomer tem pera tu res* and steam g e n e ra to r

secondary re sp o n se s i m i l a r to the LANL PORV LOCA. This su g g es ts a

c o n s i s t e n t cooldown mechanism over a l l the modeled s t a t e s r a t h e r than

sequence s p e c i f i c cooldown mechanisms f o r each c a se .

C .6 .1 .4 E x t r a p o la t io n Assumptions

A sm al1 -b reak LOCA in v o lv e s a l o s s o f h o t p r im ary c o o la n t th rough the b reak

w ith rep lacem en t o f mass in th e form o f c o ld HPI f l u i d . This mechanism

w i l l g r a d u a l ly coo l o f f the p r im ary w h ile m a in ta in in g h ig h p r e s s u r e .

C o n d it io n s p r e v a i l i n g in the p r im ary system during a PORV LOCA in c lu d e

r e l a t i v e l y c o n s ta n t n a t u r a l c i r c u l a t i o n th ro u g h bo th loops* v en t v a lve flow

( a l s o r e l a t i v e l y c o n s ta n t )* and HPI flow s t h a t b a lan ce b reak flow s on a

v o lu m e tr ic b a s i s and ap p ro x im a te ly match on a mass flow b a s i s .

Cold leg* c o ld leg-H PI m ixture* and downcomer te m p era tu re s may be o b ta in e d

from the h o t le g te m p e ra tu re i f the loop flow s and ven t v a lve f low s are

known. In t h i s study* in d iv id u a l loop f low s o f 450 Ib /s* t o t a l v en t v a lve

flow s o f 150 Ib /s* and HPI flows o f 118 l b / s were employed f o r the PORV-

s iz e d LOCA c a s e s . These loop and v en t v a lv e f low s were m a in ta in ed f o r over

700 s i n th e LANL PORV LOCA c a s e . I t i s assumed t h a t th e se c o n d i t io n s

w i l l p r e v a i l th roughou t th e sequences b e in g e v a lu a te d .

C .97

c . 6 . 2 Group 1 — Cases SBLOCAl and SBL0CA7

a . T e a p e ra tn re

These ca se s f e a t u r e n o m a l m nback o f a a i n feed w a te r and p ro p e r

o p e r a t io n of eae rgency fe e d w a te r . Upon opening o f the b re a k a t the

FORV» th e r e a c t o r w i l l t r i p and th e downcomer te m p e ra tn re w i l l i n i t i a l l y

r i s e to 572^F a t 5 s , becanse o f reduced h e a t t r a n s f e r th rough the

steam g e n e ra to r s and th e n s low ly d e c l in e because o f the r e l e a s e of

steam th rough th e TBVs and SSKVs. At 70 s HPI i n j e c t i o n b eg in s and

system cooldown commences, a t f i r s t r a t h e r r a p i d l y due to th e la rg e HPI

f low . The p ro p e r o p e r a t io n o f the main fe ed w a te r system w i l l r e s u l t

in te m p e ra tu re s ro u g h ly 86^F h ig h e r than was c a l c u l a t e d by LANL in the

PORV LOCA w ith o v e r fe e d . T h e re fo re , a downcomer te m p e ra tu re of 500°F

i s a t t a i n e d a t 550 s and rem ains c o n s ta n t to 1000 s .

T h is momentary pause i n cooldown i s due to sharp d e c re a se s in HPI

f low s in the same p e r io d . The c o n t in u in g d e c re a se in steam g e n e ra to r

e x i t te m p e ra tu re s i s masked by t h i s s ia iu lta n eo u s r e d u c t io n in HPI flow .

A f te r 1000 s , th e cooldown model was used to e x t r a p o la t e te m p era tu re s

down t o 390^F a t 7200 s ( s e e Table C.26 and F ig u re C .2 4 ) .

b . P r e s s u re

The LANL PORV LOCA case has HPI i n j e c t i o n s t a r t a t 70 s . L ikew ise , th e

INEL 2 - i n h o t l e g -b re a k LOCA case has HPI b e g in a t 78 s . T h e re fo re ,

i t i s assumed t h a t th e p r im ary d e p r e s s u r iz e s from 2180 p s i a to th e HPI

s e t p o i n t , 1500 p s i a , by 70 s . The system re a c h e s 1000 p s i a a t 550

s . I t i s assumed t h a t th e b re a k i s lo c a te d in th e vapor r e g io n of

C .98

Table C.26 P, T, and h profiles for POKV-sized LOCA group 1 sequences

PSBGl .T PSBGl .P PSBGl .h

Time(s) T(F) T ia e ( s ) P (p s ia ) Time(s) H(Btn/h) ( f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 7 0 .0 1500.0 100.0 2820.0

6 0 .0 552 .0 550.0 1000.0 150.0 210.0550.0 500.0 850.0 1670.0 7200.0 210.0

1000.0 498 .0 7200.0 1670.01500.0 494.32000.0 488.22500.0 480 .43000.0 471.53500.0 461 .94000.0 451 .94500.0 441.75000.0 431.65500.0 421.76000.0 412 .06500.0 402.67000.0 393.67200 .0 390.1

C .99

PSIfl- T(D PSBGl2 6 0 0

2200

1 8 0 0

1 4 0 0

1 0 0 0

6 0 07 m e5 0 0 02000

TIMECSEC)

F i g u r e C .24 P r e s s u r e s and t e m p e r a t u r e s f o r PO R V -sized LOCAg ro u p 1 s e q u e n c e s .

C.lOO

th e p r e s s u r i z e r . T h e re fo re , i t i s n e c e s s a ry to go w a t e r - s o l i d in the

p r e s s u r i z e r to re a c h the f i n a l p r e s s u r e of 1670 p s i a observed a t 850

s in th e LANL PORV-size IX)CA. P r e s s u r e i s assuned to remain a t t h i s

v a lu e th roughou t th e rem ainder o f th e sequence. The p r im ary s a f e ty

r e l i e f v a lv e s a re n o t c h a l le n g e d in t h i s sequence ( se e Table C.26 and

F ig u re C.24)

c . Heat T r a n s f e r C o e f f i c i e n t

2LANL e s t im a te d the downcomer h e a t t r a n s f e r c o e f f i c i e n t to 16000w/m K

(2820 B tu /h f t^ ^F ) f o r four-RCP o p e r a t io n and 1200 w/m^K (210 B tu /h

2 of t F) f o r n a t u r a l c i r c u l a t i o n . The change between th e se v a lu e s occurs

a t RCP t r i p a t 100 s ( s e e Table C .2 6 ) .

C .6 .3 Group 2 — Cases SBL0CA2, SBL0CA4, and SBL0CA8

a. T em perature

I n t h i s g roup , th e b re a k i s ta k e n to be a t o r n ea r the PORV in the

vapor r e g io n o f the p r e s s u r i z e r . T h is case fo llo w s th e LANL PORV LOCA

ou t to 1000 s because th e s p e c i f i e d o v e r fe e d resem bles the o v erfeed in

th e LANL c a l c u l a t i o n . Case SBL0CA4 i s in c lu d ed because th e s p e c i f i e d

SG d ry o u t w i l l no t o c c u r . T h e r e a f t e r , th e case fo l lo w s th e cooldown

model fo r the rem ainder o f th e t r a n s i e n t . A te m p era tu re of 3 9 2 .9°F

i s p r o j e c t e d a t 7200 s ( s e e Table C.27 and F ig u re C .25 ) .

C . l O l

Table C.27 P« X, and b profiles for PORV-sized LOCA group 2 sequences

PSBG2 .X PSBG2 .P PSBG2 .b

Tiaie(s) X(F) Xime(s) P ( p s i a ) Xime(s) H(Btu/b) (f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 70 .0 1500.0 100 .0 2820.0

6 0 .0 552.0 550.0 1000.0 150 .0 210 .0550.0 492.5 850.0 1670.0 7200.0 210 .0

1000.0 490.5 7200.0 1670.01500.0 487.62000.0 482.52500.0 475.73000.0 467 .83500 .0 459.24000.0 450.24500.0 441.05000.0 431.75500.0 422.56000 .0 413.56500 .0 404.77000 .0 396.27200.0 392.9

C.102

psrfl- rcF) PSBGaa s 0 0

2 2 0 0

1 8 0 0

1 4 0 0

1000

5 0 06 0 0 05 0 0 01 000 2 0 000

TIMECSEC)

F i g u r e C.25 P r e s s u r e s a n d t e m p e r a t u r e s f o r PO R V -sized LOCA g r o u p 2 s e q u e n c e s .

C .103

b . P r e s s u re

The p r e s s u r e b e h a v io r i s ta k e n to be i d e n t i c a l w ith the LANL PORV LOCA

c a l c u l a t i o n ( s e e Table C.27 and F ig u re C .2 5 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

The h e a t t r a n s f e r c o e f f i c i e n t s f o r t h i s group a re ta k en to be i d e n t i c a l

to group 1 ( s e e Table C .2 7 ) .

C .6 .4 Group 3 — Cases SBL0CA3 and SBL0CA9

a . Tem perature

T h is group f e a t u r e s l o s s o f main fe ed w a te r a t th e same time the PORV-

s iz e d b re a k opens . EFW comes on j u s t b e fo r e d ry o u t a t 50 s . T h e re fo re ,

th e steam g e n e r a to r s a re r e f i l l e d w i th c o ld (90^F) EFW r a t h e r than

warm (460^F) NFW. Assuming a t o t a l flow o f 120,000 lb t o f i l l b o th

SGs h a l f f u l l , th e p r im ary te m p era tu re w i l l be d ep re s se d from the LANL

te m p e ra tu re s by an average of 65^F. At a r a t e o f about 160 I b / s

p e r loop , r e f i l l would be com pleted around 425 s i n t o th e sequence .

The downcomer te m p e ra tu re would be ap p ro x im a te ly 427°F a t 550 s . The

te m p e ra tu re w i l l r i s e s l i g h t l y th rough 1500 s because of th e changeover

from SG feed t o b re a k flow as the p r i n c i p a l cooldown mechanism. Then

th e system w i l l coo l down to 3670°F by 7200 s ( see Table C.28 and

F ig u re C .2 6 ) .

C.104

Table C.28 P, T, and b profiles for PORV-sized LOCA group 3 sequences

PSBG3 .T PSBG3 .P PSBG3 .h

Time( s) T(F) Time(s) P (p s ia ) Time(s) H(Btn/h) (f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 70 .0 1500.0 100.0 2820.0

6 0 .0 552.0 550.0 1000.0 150.0 210.0550.0 427.0 850.0 1670.0 7200.0 210.0

1000.0 431.6 7200.0 1670.01500.0 433.42000.0 432.22500.0 429.03000.0 424.33500.0 418.54000.0 412.14500.0 405.25000.0 398.15500.0 390 .96000.0 383.76500.0 376.77000.0 369 .87200.0 367.0

C .1 0 5

PSIf t TCP)PSBG3

2 6 0 0 6 5 0

1 3 0 0 4 5 0

1 4 0 0 3 5 0 j-'

6 0 0 1507 0 0 00 2 0 0 0 5 0 0 0 6 0 0 01000

T I M E C S e C )

F i g u r e C .2 6 P r e s s u r e s a n d t e m p e r a t u r e s f o r P O R V -s ized LOCAg ro u p 3 s e q u e n c e s .

C .1 0 6

b . P r e s s u r e

T b is case i s ta k e n to be i d e n t i c a l to th e LANL PORV IDCA c a l c u la t io n ^

In a c t u a l p r a c t i c e , th e o v e rc o o l in g o f the systesi by EFW w i l l

t e a ip o ra r i ly reduce systesi p r e s s u r e s . However, HPI flow would in c re a s e

and s u s t a i n p r e s s u r e re c o v e ry u n t i l w a t e r - s o l i d c o n d i t io n s occu r in the

p r e s s u r i z e r and l i q u i d flow choking o c c u rs in the b re a k ( s e e Table C.28

and F ig u re C .2 6 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

T h is case i s ta k e n to be i d e n t i c a l to group 1 ( s e e Table C .2 8 ) .

C .6 .5 Group 4 — Case SBL0CA5

a. Tem perature

T h is case i s c h a r a c t e r i z e d by a l o s s o f main feed w ate r a t the time

th e POKV-sized b re a k opens. The steam g e n e ra to r s b o i l d ry and th en

a re f lo o d ed by c o ld EFW, which i s n o t c o n t r o l l e d to l e v e l . C e r t a in

e lem en ts of t h i s sequence have s i m i l a r i t i e s to th e Rancho Seco-type

e v e n t . A p p lic a b le in fo rm a t io n in c lu d e s EFW flow s o f 160 I b / s i n t o each

loop u n t i l b o th steam g e n e r a to r s and steam l i n e s a re f u l l , time of 3000

s to f i l l secondary system s w ith EFW, and d e c l in e of EFW flow r a t e to

120 I b / s i n t o each loop w ith l i q u i d flow th rough TBVs.

The te m p e ra tu re re sponse o f th e system was p r o je c te d on a p ie cew ise

b a s i s . Through 60 s , system resp o n se i s ta k en to be normal w ith the

downcomer te m p e ra tu re a t S52*^F a t th e end o f t h i s i n t e r v a l .

C .107

Between 60 s and 800 s , th e EFW s t a r t s t o overwhelm th e system , and th e

steam g e n e ra to r s co m p le te ly f i l l by the end o f t h i s p e r io d (downcomer

te m p e ra tu re = 3 8 4 .2 ^ F ) . O v e r f i l l c o n t in n e s a t 160 I b / s p e r steam

g e n e r a to r u n t i l 3000 s i n t o th e t r a n s i e n t when th e s e c o n d a r ie s become

w a t e r - s o l i d and l i q u i d flow r e s t r i c t i o n in c re a s e s p r e s s u r e and reduces

flow to 120 I b / s p e r steam g e n e r a to r . (The sequence may n o t p ro g re s s

t h i s f a r i f th e EFW tu r b i n e pump t r i p s due to low steam q u a l i t y . ) The

te m p e ra tu re a t 3000 s i s 2 3 9 .3°F . T h is assumes t h a t th e EFW is h ea te d

from 90°F to the c u r r e n t steam g e n e ra to r p r im ary e x i t a s i t p a sse s

th rough th e steam g e n e r a to r s . The LANL Rancho S eco -type t r a n s i e n t

c a l c u l a t i o n b e a r s t h i s assum ption o u t , b u t i t i s s t i l l p o s s i b le t h a t

much o f the feed w ate r w i l l bypass d i r e c t l y to th e steam l i n e s and

n o t coo l th e system down. In th e f i n a l mode (120 I b / s ) , te m p era tu re

re a c h e s 171.3*^F a t 7200 s . This seve re o v e rc o o l in g i s due to the

compounding o f HPI i n j e c t i o n and SG o v e rfeed cooldown mechanisms (see

Table C.29 and F ig u re C .2 7 ) .

b . P r e s s u re

The m assive o v e rc o o l in g w i l l d e c re a se system p r e s s u r e below the v a lu e s

used p r e v io u s l y . I t i s assumed t h a t the HPI f a i l s to " g a in " on the

system u n t i l the steam g e n e ra to r s a re r e f i l l e d w ith EFW, o r fo r 800

s . T h is w i l l d e lay th e a t ta in m e n t o f f i n a l system p r e s s u r e (1670 p s ia )

to 1650 s ( s e e Table C.29 and F ig u re € .2 7 ) .

C .108

Table C.29 P. T, and h profiles for PORV-sized LOCA group 4 sequences

PSBG4 .T PSBG4 .P PSBG4 .b

Time(s) T(F) Time(s) P (p s ia ) Time(s) H(Btn/b) (f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 570.0 70 .0 1500.0 100.0 2820.0

6 0 .0 552.0 550.0 1000.0 150.0 210.0500.0 430.9 1350.0 1000.0 7200.0 210.0800.0 394.2 1650.0 1670.0

1000.0 373.5 7200.0 1670.01500.0 328.72000.0 292.52500.0 263.13000.0 239.33500.0 226 .44000.0 215.24500.0 205 .45000.0 196.95500.0 189.56000.0 183.26500.0 177.77000.0 173.07200.0 171.3

C .109

psifi rcF) PSBG4

2 6 0 0

2200

1 3 0 0

1 4 0 0

1000

6 0 04 0 0 00 1000 3 0 0 0

TIMECSEC)

F i g u r e C.27 P r e s s u r e s and t e m p e r a t u r e s f o r PORV-sized LOCA group 4 s e q u e n c e s .

C . l lO

c . Heat T r a n s f e r C o e f f i c i e n t

T h is case i s i d e n t i c a l t o gronp 1 ( s e e Table C .29 ) .

C .6 .6 Gronp 5 — Case SBL0CA6

a. Tem peratnre

In t h i s c a s e , th e POKV-sized b reak i s c o n p l ic a te d by f a i l u r e o f two

TBVs in th e open p o s i t i o n on SGA. Main feed w ate r a t 400^F i s assnmed

a v a i l a b l e o n t i l s te a n g e n e ra to r A feed w a te r i s i s o l a t e d a t 20 s i n .

The te m p era tn re i s assnmed to r i s e from 5 S 5 ° F to 572°F a t 5 s and

th e n drop to SS2°F as a r e s u l t o f IBV o p e r a t io n . T h e r e a f t e r , the

TBVs ro n a in open, and th e system te m p e ra tn re d rops m ain ly because of

h e a t l o s s as steam th rough the open TBVs. The downcomer te m p era tn re

f a l l s t o SSI.S'^F a t 1200 s where feed w a te r i s o l a t i o n o c c u rs . Steam

lo s s c o n t in n e s u n t i l a f f e c t e d SGs d ry out a t 2500 s where a minimum

te m p era tu re of S II .T^’f (av e rag e ) o c c u r s . I f th e TBVs were a l s o

i s o l a t e d a t 1200 s , t h i s a d d i t i o n a l c o o l in g would no t o ccu r . I f loop

B has s ta g n a t e d , th e n minimum te m p e ra tu re s around 250^F w i l l occur a t

t h i s p o i n t .

With steam g e n e r a to r A removed as a h e a t s in k , th e system e q u i l i b r a t e s ,

and downcomer te m p e ra tu re s r i s e as h o t leg te m p era tu re s remain s tead y

u n t i l HPI f low th rough becomes th e p r i n c i p a l h e a t removal mechanism.

A f te r r i s i n g t o 342°F between 3500 and 4000 s , downcomer tem p era tu re

d e c l in e s to 3 2 5 .6^F a t 7200 s . (See Table C.30 and F ig u re C .28 .)

C . l l l

Table C.30 P, T, and h profiles for PORV-sized LOCA gronp S sequences

PSBGS .T PSBG5 .P PSBG5 .H

Tiaie ( s ) T(F) T iD e(s) P (p s ia ) Tim e(s) H(Btn/h) (f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 70 .0 1500.0 100 .0 2820.0

6 0 .0 552.0 550.0 1000.0 150 .0 210 .0200.0 423.9 1200.0 1000.0 7200.0 210.0800.0 368.8 1500.0 1670.0

1200.0 351 .8 7200.0 1670.01600.0 338 .02000.0 325.62200.0 319 .82500.0 311.73000.0 341.23500.0 342.44000.0 342.14500.0 340 .95000.0 338 .95500.0 336.46000.0 333.56500.0 330.37000.0 326 .97200.0 325.6

C .112

P S I R TCP)PSBGS

2 S 0 0

2200

1 8 0 0

14 0 0

1000

B000 1000 3 0 0 0 7 0 0 04 0 0 0

TIME(SEC)

F i g u r e C .28 P r e s s u r e s a n d t e m p e r a t u r e s f o r P O R V -sized LOCAg r o u p 5 s e q u e n c e s .

C .1 1 3

b . P r e s s u re

Response i s assoaed to be s i a i l a r to t h a t o f gronp 4 excep t t h a t

p r e s s u r e b e g in s t o r i s e a t SGA i s o l a t i o n (1200 s ) . (See Table C.30

and F ig u re C .2 8 .)

c . Heat T r a n s f e r C o e f f i c i e n t

T h is case i s i d e n t i c a l to group 1 ( s e e Table C .3 0 ) .

C .114

C.7 Feedwatex Txansient Cases

C .7 .1 ORNL-Defined F eedw ate r T r a n s ie n t Cases

The c o n d i t io n s f o r th e seven OBNL-defined feed w ate r t r a n s i e n t ca se s a re

d e s c r ib e d in Table C .31 . Dne to th e v a r i a t i o n s in most of th e sequences,

on ly c a s e s 1 and 2 were grouped f o r e v a lu a t io n . The cases a re d e sc r ib e d

in d e t a i l below.

C .7 .1 .1 Bases

INEL maximum s u s t a in a b le o v e r fe e d

LANL Rancho S eco-type t r a n s i e n t

C .7 .2 .1 D e p a r tu re s from Bases

a . Most c a se s a llow main fe e d w a te r t r i p and EFW c o n t r o l on l e v e l w hile

b ase c a s e s do n o t .

b . SG d ry o u t ca se s f e a t u r e ex tended d e la y s in feed w ate r r e s t o r a t i o n (20

min) t o a l lo w h ea tu p o f v e s s e l .

C .7 .1 .3 A p p lic a b le Data from O ther Cases

LANL TBV c a s e s 5A, SC, 6 k , 6C a l s o f e a t u r e o v e rfeed s and p ro v id e feed w ate r

te m p e ra tu re t r e n d in fo rm a t io n and system b e h a v io r w ith RCPs o p e r a t in g .

C .7 .1 .4 E x t r a p o la t io n A ssum ptions, P ro c e d u re s , and R e s u l t s

Steam g e n e r a to r o v e r fe e d s a re so u rces o f co o l in g t h a t a l s o in c re a s e the

t o t a l system h e a t c a p a c i ty (m a s s ) . The system th e r e f o r e becomes more

r e s i s t a n t to f u r t h e r te m p e ra tu re changes u n le s s o th e r cooldown mechanisms,

C.115

Table C.31 Feedwater tr a n s ie n t cases

Case FW- (o r OVRFD-)

C o n d itio n * 1 2 3 4 5 6 7

Main F eedw ater

SGA runback f a i l u r e X X X

Both SG runback f a i l u r e X X

LOMFV a t tim e = 0 .0 X X

MFWP t r i p h ig h SG le v e l X X X X

MFWP h ig h SG le v e l t r i p f a i l u r e X

Emeraencv F eedw ater

EFW works as d es ig n ed X X X X X

EFW on manual X X

O n era to r A c tio n s

RCP t r i p a t HPI + 30 s X X X X X

F a i l to t r i p RCP X X

EFW r e s to r e d f u l l flow a t 20 min X

MFW r e s to r e d f u l l flow a t 20 min X

* C o n d itio n s common to a l l c a s e s : secondary p re s s u re c o n tro l system s

f u l l power, o p e ra te as

decay h e a t 1 .0 tim es ANS, d e s ig n e d , p rim ary p re s s u re

c o n tro l system o p e ra te as d e s ig n e d , a l l ECCS components o p e ra te a s d esig n ed

C.116

such as HPI f l o v , a re a c t i v a t e d . F o llow ing r e a c to r t r i p , main feedw ate r

te m p era tn re s t a r t s t o d e c l in e because of lo s s o f h e a t e r steam. For

sequences where l e v e l t r i p s o f MFW o ccu r , main feed w ate r te m p era tu re s s ta y

above 350 to 400°F. R e s u l t in g system te m p e ra tu re s a re bounded by normal

o p e ra t in g te m p e ra tu re s and t h i s feed te m p e ra tu re . I f the ov erfeed uses

90*^F EFW, th e r e s u l t i n g te m p e ra tu re s can be much low er.

In most c a s e s , t r a n s i e n t e v a l u a t i o n w i l l siiiq>ly use the a p p l ic a b le p o r t i o n s

o f th e base case c a l c u l a t i o n s . Where e x t r a p o l a t i o n i s n e c e s s a ry , the

cooldown model i s u sed .

C .7 .2 Cases FWl and FW2

a. Tem perature

I n t h i s c a s e , MFW runback f a i l u r e o ccu rs in SGA w hile SGB runback

succeeds MFW pump t r i p on h ig h SG l e v e l . EFW and a l l o th e r systems

o p e ra te as d e s ig n e d . E a r ly in th e t r a n s i e n t , SSRV and TBV steam

r e l e a s e s accoun t f o r a la rg e p o r t i o n of the c o o l in g . A l l of th e se

c o n d i t io n s fo l lo w LANL TBV case SA ou t to 6 0 s when the MFW pump t r i p s

on h igh l e v e l . High p r e s s u r e in SGA p re v e n ts f u r t h e r flow in t o the

SG from HW/CB pump a c t i o n . The downcomer te m p era tu re a t t h i s p o in t

i s 552°F. HPI does n o t come on and th e RCPs rem ain on. The system

i s coo led t o 548^F by c o n t in u in g o p e r a t io n o f th e TBVs w ith o c c a s s io n a l

EFW flow to SGB. T h is f i n a l te m p e ra tu re i s assumed to be reached by

200 s . T em peratu res a re documented in f i l e s FWl.T and FW2 .T. This

case i s ve ry s i m i l a r to FW4 in which HPI comes on bu t the RCPs a re

l e f t ru n n in g . T h e re fo re , HPI does n o t s i g n i f i c a n t l y a f f e c t downcomer

C.117

t e n p e r a tn r e because o f e x c e l l e n t m ix ing . I f HPI comes on and th e RCPs

a re t r i p p e d , as in case FW2, th e te m p e ra tu re s and p r e s s u r e s r e p o r te d in

case r e q u i r e d FW3 would be o b ta in e d ( s e e Table C.32 and F ig u re € .2 9 ) .

b . P r e s s u re

P re s s u re i s assumed to fo l lo w LANL IBV case SA out to 60 s . The

p r e s s u r e d e c l in e s from 2180 p s i a to 1760 p s i a over t h i s p e r io d . With

the c o o l in g mechanism c u r t a i l e d , r e d u c t io n to HPI s e t p o in t does n o t

o c c u r . With oyer 6 f t o f w a te r s t i l l in th e p r e s s u r i z e r , i t i s assumed

t h a t th e h e a t e r s a r e a c t i v a t e d and accom plish r e p r e s s u r i z a t i o n to 2180

p s i a by 200 s ( s e e T ab le € .32 and F ig u re € .2 9 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

S ince th e r e a c t o r c o o la n t pumps rem ain o f f th roughou t the t r a n s i e n t ,

th e h e a t t r a n s f e r c o e f f i c i e n t i s c o n s ta n t a t 2820 B tu /h f t F ( s e e

Table € .3 2 ) .

€ .7 .3 Case FW3

a . Tem perature

In t h i s case th e s t a r t u p flow c o n t r o l v a lv e s rem ain open to b o th steam

g e n e r a to r s , c au s in g main feed w a te r o v e r fe e d to b o th steam g e n e r a to r s .

Both steam g e n e r a to r s reac h the MFW t r i p l e v e l a t about 250 s (LANL

case 6A ). Downcomer te m p era tu re i s abou t 530°F a t t h i s p o in t (from

INEL o v e r f e e d ) . HPI t r i p has n o t y e t o ccu rre d and does n o t occur f o r

an o th e r 20 s in th e INEL o v e r fe e d . I f HPI does n o t come on, th e

system te m p e ra tu re s w i l l b eg in t o r e c o v e r . To s a t i s f y th e s c e n a r io

€.118

Table C.32 P, T, and h profiles for feedwater sequences 1 and 2

FWl .T FWl .? FWl .h

Time( s) T(F) T in e ( s ) P (p s ia ) Time(s) H(Btu/h)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 6 0 .0 1760.0 7200.0 2820.0

6 0 .0 552.0 200 .0 2180.0200 .0 548.0 7200.0 2180.0

7200.0 548.0

C .119

P S I f t T C P

2800- 6 5 0

2 2 0 0 5 5 0

1 8 0 0 4 5 0

1 4 0 0 3 5 0

1 0 0 0 2 5 0

8 0 0 1 5 0

FW-L

J ________________ I________________ I________________L J_________ L.0 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 6 0 0 0 7 0 0 0

T I M E (S E C )

F i g u r e C.29 P r e s s u r e s and t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e s 1 and 2,

C .120

r e q u i re m e n ts , i t i s assumed t h a t the HPI s e t p o in t (1500 p s i ) i s

reached a t 250 s and t h a t th e RCPs a re t r i p p e d 30 s l a t e r . Downcomer

te m p e ra tu re s s ta y around 5 3 2 .7^F a t 280 s , when the RCPs a re t r i p p e d

and th e n drop to 493 . 8°F a t 350 s where n a t u r a l c i r c u l a t i o n flow i s

e s t a b l i s h e d . Upon re a c h in g th e PORV s e t p o in t p r e s s u r e a t 550 s , flow

d rops from an average 100 I b / s t o a f i n a l va lue of 70 I b / s f o r the

rem ainder o f th e t r a n s i e n t . The r e d u c t io n in c o o lin g coupled t o decay

h e a t in p u t r a i s e s th e h o t le g te m p e ra tu re u n t i l th e TBVs a c tu a te and

the c o n t r o l steam g e n e ra to r te m p e ra tu re goes to 547°F. A f te r 5000 s ,

decay h e a t has reduced to th e p o in t t h a t the TBVs rem ain c lo se d and

the system c o o ls down, because o f HPI f low , t o a f i n a l va lue o f 5 1 0 .2°F

a t 7200 8 ( s e e Table C.33 and F ig u re C .3 0 ) .

b . P r e s s u re

P re s s u re i s assumed to drop to 1500 p s i a a t 250 s to b r in g about HPI

i n j e c t i o n . The HPI i s assumed to r e s t o r e the system to the PORV s e t

p o in t p r e s s u r e 2430 p s i a a t 550 s . P r e s s u re rem ains a t t h i s va lue f o r

the r e s t o f th e sequence ( s e e Table C.33 and F ig u re C .30 ) .

Heat T r a n s f e r C o e f f i c i e n t

Heat t r a n s f e r c o e f f i c i e n t d rops from 2180 B tu / h / f t^ ° F a t RCP t r i p (250

s) to 210 B t u / h / f t ^ ° F a f t e r pump rundown a t 300 s and rem ains a t t h i s

v a lue f o r th e rem a inder o f th e sequence ( s e e Table C .3 3 ) .

C.121

Table C.,33 P. T, and h p r o f i l e s f o r feed w a te r sequence 3

FW3 .T FW3 .P FW3 .b

Tiflw(s) T(F) T ia e ( s ) P (p s ia ) T ia e ( s ) H (Btn/h)(f t* * 2 F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 250 .0 1500.0 250.0 2820.0

60 .0 552.0 550.0 2430.0 300 .0 210.0250.0 531.1 7200.0 2430.0 7200.0 210.0280.0 532.7350 .0 493.8500.0 496.9750.0 515.7

5000.0 515.77200.0 510.2

C.122

p s r f f TCP)PW3

IS 0 a

3 2 0 0

1 8 0 0

1 4 0 0

1000

S 0 02 0 0 0 4 0 0 00 1000 000d

T I M E (S E C )

F i g u r e C .3 0 P r e s s u r e s a n d t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e 3.

C .1 2 3

c . 7 .4 Case FW4

a . Tem perature

T his case i s s i m i l a r to case FW3 ex cep t t h a t th e o p e r a to r f a i l s to t r i p

th e RCPs a f t e r HPI i n i t i a t i o n . The e x te n s iv e mixing and a d d i t i o n a l

h e a t in p u t w i l l cause th e te m p era tu re to re c o v e r from 532°F a t 280 s

to 547°F a t about 400 s where i t i s c o n t r o l l e d by TBV a c t io n f o r the

r e s t o f th e sequence (s e e Table C.34 and F ig u re C .3 1 ) .

b . P r e s s u re

T h is case i s ta k e n to be i d e n t i c a l to case FW3 (s e e Table C.34 and

F ig u re C .3 1 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

S ince th e RCPs a re n o t t r i p p e d , t h i s case i s ta k e n to be i d e n t i c a l to

case FWl ( s e e Table C .3 4 ) .

C .7 .5 Case FW5

a . Tem perature

This case f e a t u r e s an o v e r fe e d to SGA where the h ig h SG l e v e l MFW

pump t r i p a l s o f a i l s . SGB feed w ate r i s p r o p e r ly c o n t r o l l e d by ICS.

SGA r e c e iv e s a p p ro x im a te ly 1500 I b / s o f MFW in t h i s c a se , compared to

th e 300 I b / s when b o th SGs a r e b e ing o v e r fe d . T h e re fo re , th e time

to MFW t r i p on low steam q u a l i t y in the steam l i n e w i l l be dropped

from 417 s in th e INEL o v e r fe e d case to a p p ro x im a te ly 85 s . The

te m p e ra tu re re sponse i s assumed to be s i m i l a r to case FWl b e c a u se .

C .1 2 4

T able C. 34 P. T. and h p r o f i l e s fox feedw ater sequence 4

FW3 .T FW3 .? FW3 .h

Tim e(s) T(F) T in e ( s ) P ( p s i a ) Time(s) H(Btu/li)( f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 250.0 1500.0 7200.0 2820.0

60 .0 552.0 600.0 2430.0250.0 530.0 7200.0 2430.0280 .0 535.6600 .0 548.0

7200.0 548.0

C.125

PSIR- TCP)

2 6 0 0

FW4

2 2 0 0

1 3 0 0

1 4 0 0

1000

6 0 07 0 0 00 1000 3 0 0 0

TIMECSEC)

F i g u r e C .3 1 P r e s s u r e s an d t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e 4,

C.126

a f t e r the steam g e n e ra to r i s f u l l , a d d i t i o n a l feedw ater w i l l on ly

d i s p la c e o th e r fee d w a te r t h a t has n o t had time to absorb h e a t . The

minimum te m p e ra tn re i s 548°F a t 85 s . The HPI system does n o t come

on and t h e r e f o r e th e RCPs a re no t t r i p p e d . Even i f th e se t r i p s had

o c c u r re d , th e te m p e ra tu re s would rem ain a t or above the f i n a l va lue of

510^F o b ta in e d f o r case FW3 ( s e e Table € .35 and F ig u re € .3 2 ) .

b . P r e s s u re

P re s s u re i s assumed t o d e c l in e a t the same r a t e as observed in case

FWl. At 85 s , th e p r e s s u r e would be 1585.0 p s i a . This i s q u i t e c lo se

to th e HPI s e t p o in t and may p o s s i b ly be reached in a t r a n s i e n t of

t h i s ty p e . However, i t i s assumed t h a t the HPI does no t come on and

t h a t the p r e s s u r i z e r h e a t e r s a re a b le to r e s t o r e the system to 2180

p s i a by 285 s ( s e e Table € .35 and F ig u re € .3 2 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

S ince the RCPs a re n o t t r i p p e d , th e h e a t t r a n s f e r c o e f f i c i e n t rem ains0 A

a t i t s i n i t i a l v a lue o f 2180 B t u / h / f t F th roughou t the t r a n s i e n t in

case FWl ( s e e Table € .3 5 ) .

€ .7 .6 Case FW6

a . Tem perature

This case f e a t u r e s steam g e n e ra to r d ry o u t w ith a 20-min d e la y u n t i l EFW

i s r e s t o r e d a t f u l l f low . EFW i s n o t c o n t r o l l e d to l e v e l . HPI comes

on as d e s ig n e d , and th e RCPs a re t r i p p e d 30 s a f t e r HPI i n i t i a t i o n .

The e a r l y p o r t i o n s o f t h i s t r a n s i e n t a re v ery s im i l a r to the Rancho

C.127

Table C..35 P, T, and b p r o f i l e s f o r fe e d w a te r sequence 5

FW5 .X FW5 .? FW5 .b

TimeCs) T(F) Time(s) P (p s ia ) Time( s) H(Btu/b)(f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.05 .0 572.0 60 .0 1760.0 7200.0 2820.0

60 .0 552.0 85.0 1585.085 .0 548.0 285.0 2180.0

7200.0 548.0 7200.0 2180.0

C.128

p s r f i T (F )rw 5

2 S 0 0 G50

1 8 0 0 4 5 0

1 4 0 0 350-

1502 0 0 0 5 0 0 00 1000 4 0 0 0

T I M E ( S E C )

F i g u r e C .32 P r e s s u r e s an d t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e 5 .

C.129

Seco -type e v e n t . In fo l lo w in g t h i s sequence , th e downcomer te m p era tu re

would r i s e from i t s i n i t i a l v a lue of S55^F to 581^F a t 8 s and

th e n to 644°F a t 1200 s (d T /d t= + 0 .0524°F /s ) T h is te m p e ra tu re i s 20°F

below the s a t u r a t i o n te m p e ra tu re f o r the PORV s e t p o in t p r e s s u r e .

The i n t r o d u c t i o n o f c o ld (90°F) EFW a t 1200 s w i l l cause a d e c l in e

(d T /d t= 0 .2 2 8 °F /s ) t o 548°F a t 1535 s when th e RCPs a re t r i p p e d . ( In

th e LANL Rancho S eco -type t r a n s i e n t , th e te m p e ra tu re a t HPI = 30 s i s

548°F. I t i s assumed t h a t c o o l in g th e system to t h i s s t a t e w i l l y i e l d

com parable HPI r e s p o n s e . ) A f te r th e pumps s p in down, th e system i s

assumed to a t t a i n n a t u r a l c i r c u l a t i o n flow s on th e o rd e r of 820 l b / s

p e r loop and t o t a l v e n t v a lv e f low s o f 45 I b / s , as o bserved in LANL TBV

c a s e s 6A, 6B, and 6C under s im i l a r h ig h cooldown r a t e c i rc u m s ta n c e s .

In t h i s reg im e, th e downcomer te m p era tu re d e c re a s e s to 424*^F a t 2200

s when th e steam g e n e ra to r s a r e l i q u i d f u l l , and th e HPI flow d e c re a se s

as th e p rim ary i s n e a r in g th e PORV s e t p o in t p r e s s u r e . The te m p era tu re

a t 7200 s i s 295°F, i f a l l flow s co n t in u e as s t a t e d . However, i t i s

l i k e l y t h a t EFW w i l l be l o s t a t some e a r l i e r p o in t because of low steam

q u a l i t y in th e seco n d a ry , im pacting th e o p e r a t io n o f th e t u r b i n e - d r iv e n

pump. As a r e s u l t , th e te m p e ra tu re s a f t e r th e l o s s o f EFW would be

h ig h e r th an th e v a lu e s p r e s e n te d h e re ( see Table C.36 and F ig u re C .3 3 ) .

b . P r e s s u re

P r e s s u r e i s g e n e r a l l y ta k e n to mimic th e Rancho S eco-type even t

c a l c u l a t e d by LANL. From an i n i t i a l va lue o f 2180 p s i a , th e p re s s u re

in c re a s e s to th e PORV s e t p o i n t , 2430 p s i a , a t 226 s and rem ains

u n t i l EFW a c t i v a t i o n a t 1200 s . (E a r ly d ip s and peaks in th e LANL

C.130

T ab le C..36 P, T. and b p r o f i l e s f o r feed w ate r sequence 6

FW6 .1 FW6 .P FW6 .b

Tiaie(s) T(F) Time(s) P ( p s i a ) Time(s) H(Btu/b)(f t**2F)

0 .0 555.0 0 .0 2180.0 0 .0 2820.08 .0 581.0 226 .0 2430.0 1540.0 2820.0

1320.0 644.0 1320.0 2430.0 1590.0 210.01540.0 548.0 1510.0 1500.0 7200.0 210.02200.0 423.7 2300.0 2430.03000.0 398.5 7200.0 2430.04000.0 369.55000.0 343.36000.0 319 .97000.0 299.17200.0 295.2

C.131

PSIfl TCD FWSa S 0 0

2 2 0 0

1 9 0 0

I 4 0 0

1000

6 0 03 0 0 0 6 0 0 0 7 0 0 00 1000 4 0 0 0 5 0 0 0

TIME(SEC)

F i g u r e C.33 P r e s s u r e s and t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e 6.

C.132

c a l c u l a t i o n were no t in c ln d e d because o f the h ig h system te m p e ra tu r e s . )

P r e s s u r e d rops t o 1500 p s i a a t 1510 s u h e re HPI comes on to r e s e rv e

th e t r e n d . R e p r e s s u r iz a t io n to th e f i n a l p r e s s u r e , 2430 p s i a . occurs

a t 2300 s ( s e e Table C.36 and F ig u re C .3 3 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

The downcomer h e a t t r a n s f e r c o e f f i c i e n t r e t a i n s i t s i n i t i a l v a lu e , 2820

B t u / h / f t F , t o 1540 s when th e RCPs a r e t r i p p e d . A f te r a 5 0 -s c o a s t

down p e r io d , th e h e a t t r a n s f e r c o e f f i c i e n t o b ta in s i t s f i n a l va lue of

210 B t u / h / f t ^ ° F ( s e e Table C . 3 6 ) .

€ . 7 . 7 Case FW7

a. Tem perature

This ca se i s s i m i l a r to FW6 ex cep t t h a t the steam g e n e ra to r s a re

r e f i l l e d w ith NFW a t f u l l flow s t a r t i n g a t 20 min. Tem perature

b e h a v io r to 1200 s i s th e same as case FW6. A flow o f 750 l b / s of

450°F w a te r t o each steam g e n e ra to r red u ce s downcomer te m p era tu re to

545^F a t 1280 s when th e RCPs a re assumed to be t r i p p e d . The flow

p a th sw i tch es o v e r to th e EFW h e a d e r s , and flow i s l im i te d to th e SUFCV

va lue o f 112 .5 I b / s p e r steam g e n e r a to r . The steam g e n e ra to r s f i l l ,

and th e MFW t r i p on low steam l i n e q u a l i t y i s assumed to occur a t 2100

s w ith a downcomer te m p era tu re o f 506°F. With HPI flow th rough as the

o n ly cooldown mechanism, th e te m p e ra tu re r i s e s to 528°F a t 5000 s and

d e c l in e s to 523^F a t 7200 s ( s e e Table C.37 and F ig u re C .34 ) .

C.133

Table C..37 P. T, and b p r o f i l e s f o r feed w a te r sequence 7

VWl .T FW7 .P FW7 .b

T in e ( s ) T(F) Tim e(s) P (p s ia ) T i i ie (s ) H(Btn/b)( f t**2F )

0 .0 555.0 0 .0 2180.0 0 .0 2820.08 .0 581.0 226 .0 2430.0 1280.0 2820.0

1200.0 644.0 1200.0 2430.0 1330.0 210.01280.0 545.0 1250.0 1500.0 7200.0 210.01900.0 510.3 2100.0 2430.02100.0 506.5 7200.0 2430.03000 .0 522.04000 .0 527.55000.0 528.86000.0 527.37000.0 524.27200 .0 523.4

C.13A

PSIfl- T ( DFw;

2 6 0 0 6 5 0

1 8 0 0 4 5 0

1 4 0 0 3 5 0

1 0 0 0 2 5 0

1 5 06 0 00 3 0 0 0 4 0 0 0 5 0 0 0 7 0 0 0

TIMECSEC)

F i g u r e C .34 P r e s s u r e s a n d t e m p e r a t u r e s f o r f e e d w a t e r s e q u e n c e 7,

C.135

b . P r e s s u r e

P r e s s u r e s f o l l o v case FW6 to 1200 s . The m assive in - r u s h of

and subsequen t p r im ary h e a t removal i s ta k e n to drop th e p r e s s u r e

to th e HPI s e t p o i n t , 1500 p s i a , a t 1250 s . The HPI i s assumed

to check f u r t h e r d e p r e s s u r i z a t i o n and b eg in r e p r e s s u r i z a t i o n , a l th o u g h

i t i s p o s s i b l e t h a t p r e s s u r e may y e t d e c re a se because of con t in u ed

o v e rc o o l in g . The PORV s e t p o in t p r e s s u r e i s assumed t o be reached a t

2100 s where i t rem ains f o r th e d u r a t i o n o f th e sequence ( s e e Table

C.37 and F ig u re C .3 4 ) .

c . Heat T r a n s f e r C o e f f i c i e n t

The h e a t t r a n s f e r c o e f f i c i e n t i s assumed to rem ain c o n s ta n t a t i t s

i n i t i a l v a lu e , 2820 B t u / h / f t ^ ° F , u n t i l RCP t r i p a t 1280 s , when i t

ramps down to i t s f i n a l v a lue o f 210 B t u / h / f t F by 1330 s ( s e e Table

C .3 7 ) .

C.136

C.8 Steam G enera to r Tnbe R upture

A steam g e n e ra to r tube r u p tu r e i s a form of smal 1 -b reak LOCA. The case

p re p a re d by INEL was d i g i t i z e d and ap p ea rs in Table C.38 and F ig u re C.35.

T h is case does no t appea r w orthy o f concern from FTS s t a n d p o in t , l a r g e ly

because of th e sm alln ess of th e b re a k , which w ithdraw s l e s s flow (40 I b / s )

th a n th e HPI i n j e c t s a t th e PORV s e t p o in t p r e s s u r e (70 I b / s ) . G u i l l o t in e

b re a k s o f two tu b e s would g ive a b re a k s i z e comparable to a s tuck -open PORV.

The te m p e ra tu re s , p r e s s u r e s , and h e a t t r a n s f e r c o e f f i c i e n t s f o r case PORV-

s iz e d LOCA group 11 may be r e p r e s e n t a t i v e of a tw o-tube ru p tu re i f flow

c o m p le x i t ie s do n o t g r e a t l y a l t e r the r e s u l t s . L a rg e r , m u l t i tu b e ru p tu re

i n c i d e n t s would ten d to resem ble l a r g e r LOCAs, a l th o u g h v o id fo rm a t io n in

th e upper hand and candy canes and s i m i l a r e f f e c t s would g r e a t l y co m plica te

th e sequence .

C.137

Table C.38 P, T, and h p r o f i l e s f o r s i n g l e - tu b e s t e a a g e n e ra to r tnbe ru p tu r e case

SGTR .T SGTR .? SGTR .h

Time ( s) T(F) Time(s) P (p s ia ) Time(s) H (Btu/b)( f t* * 2 F )

0 .0 557.0 0 .0 2180.0 0 .0 2820.0320 .0 563.0 160.0 2110.0 975.0 2820.0385 .0 552.7 320.0 2090.0 1025.0 210 .0625 .0 552.7 366.0 1640.0 7200.0 210 .0795 .0 557.0 410.0 1610.0940.0 552.7 650.0 1610.0

1040.0 458.0 720.0 1640.01760.0 450.0 925.0 1509.02240.0 469.0 1135.0 1610.07200.0 477.0 1350.0 1610.0

1550.0 1815.02200.0 2430.07200.0 2430.0

i

€.138

psrft rcF) SGTR

1 8 0 0 4 5 0

1 4 0 0 3 5 0

1 0 0 0 2 5 0

150.0 1 0 0 0 3 0 0 0 4 0 0 0

T I M E ( S E C )

F i g u r e C.35 P r e s s u r e s and t e m p e r a t u r e s f o r s i n g l e t u b e s team g e n e r a t o r t u b e r u p t u r e c a s e .

C.139

APPENDIX D

CONTRIBUTION TO P(F|E) OF FLAWS IN THE CIRCUMFERENTIAL

WELDS AND THE BASE MATERIAL

Flaws anywhere in the beltline region of the reactor vessel will contri­

bute to the probability of vessel failure. However, aside from the

effect of flaw depth, some contribute more than others because of

differences in orientation, length, local chemistry of the material, and

local fluence. Axial flaws have the highest values of K^, and in

Oconee-1 the axial welds have higher concentrations of copper than the

circumferential welds and the base material.

Because the difference in copper concentration between the axieil welds

and base material is rather large in terms of radiation damage, the

extended surface length of an axial flaw in a weld tends to be limited

to the height of a shell course, and for deep flaws this limit on sur­

face length results in significantly lower values than for much

longer flaws. The surface length of extended flaws in the circumferen­

tial welds and in the base material are not limited by this mechanism,

although the lengths of these flaws may be limited by gradients in flu­

ence and coolant temperature.

Thus far our fracture-mechanics model is not sufficiently sophisti­

cated to consider gradients in fluence and coolant temperature along the

specified surface flaw path. In lieu of considering this sort of

detail, all flaws in the circumferential welds and in the base material

were assumed to be two dimensional. It was believed that even under

D-1

these conservative conditions flaws in the circumferential welds and in

the base material would not be dominant in terms of the calculated pro­

bability of vessel failure.

To be certain that the above assumption was reasonable, a few comparison

calculations were made for circumferential flaws in the circumferential

welds, for axial flaws in the base material, and for axial flaws in the

axial welds. The flaw density was assumed to be the same for the three

categories of flaws considered, and since the volume of the base

material is much greater than that of the welds, the base material con­

tributed many more flaws than the welds.

The chemistry, maximum fluences, and initial values of RTNDT for each

distinct area of the vessel considered for the three categories of flaws

are given in Table 5.2. In an attempt to account for the azimuthal

variation in fluence in the base plate without dividing the plate region

into several zones, each with a different fluence, an average fluence

was used in accordance with the data in Table 5.2 and Reference 1.

Also, the initial values of RTNDT given in Table 5.2 for the base

material were reduced by 14°C to account for a lower radiation damage2rate in the base material than in the welds. The radiation-damage

trend curve [ARTNDT = f(F, Cu, Ni)] in the fracture-mechanics model

corresponds to weld material only.

The comparison calculations were made for transient No. 44 and for 32

EFPy. The results indicate that the circumferential flaws add '^ 5% to

P(f1e) and the base material ' 30$. Since the contributions were so

D-2

small, flaws In the base material and the circumferential welds were not

Included In the remainder of the studies.

References

1. "Reactor Vessel Pressurized Thermal Shock Evaluation," DPC-RS-1001,

Duke Power Company Oconee Nuclear Station, January 1982.

2. P. N. Randall, U.S. Nuclear Regulatory Commission, personal communi­

cation to R. D. Cheverton, Oak Ridge National Laboratory.

D -3

APPENDIX E

COMPILATION OF RESULTS OF OCONEE-1 PROBABILISTIC

FRACTURE-MECHANICS ANALYSIS

Detailed results of the Oconee-1 probabilistic fracture-mechanics

analysis are included in this appendix so that a more thorough under­

standing of the effect of the various assumptions used in the fracture-

mechanics model and as related to input to the fracture-mechanics

analysis can be obtained. For instance, the duration of all postulated

transients for this study was specified as two hours. In many cases

most of the failures do not occur until late in the transient. If the

duration of the transient were one instead of two hours, P(f |e ) would be

reduced substantially (' two orders of magnitude for transient No. 44).

Sets of data are included in this appendix for each of the transients

for which P(f |e ) > lO”". A set of data includes, in this order, (1) a

figure of primary-systan pressure, downcomer coolant temperature, and

fluid-film heat-transfer coefficient vs time in transientj (2) a summary

of digital output that includes P(f |e ) for each weld and the vessel, the

estimated error in P(FlE), and histogram data for crack depths, time of

failure (TWC propagation), times and values of T - RTNDT at the crack tip

corresponding to initiation, arrest and failure events; (3) a plot of

vessel wall temperature vs a/w, t; (4) a plot of vessel wall temperature vs

t, a/w; and (5) a set of critical-crack-depth curves obtained using -2a

values of and mean values of all other parameters, and fluences

corresponding to 32 EFPY. The various curves in the set of critical-

crack-depth curves are identified in Figure 5.17 (see Chapter 5).

E-1

TRANSIENT NO. 1 (TBVG1)

E -3

0.0 I _

4.0

6.0H

TC(W

/M«i

^2xK

)8.

0 10

.0

12.0

16.0

i6.0

20.0

>—

JTE

MP.

(DEG

.C.)

300.

033

0.0

270.

0IS

O.O

210.

090

.012

0.0

30.0

60.0

CO O O O z n n o r* o CU < 63 to O V 00 O)

z

“0rj

oC

OC

O

63 O

b 0

.020

.014

.016

.018

.06.0

6.010.

012.

02.0

4.0

PRES

S.(M

Pfl)

IPTS OCONEE CUD TBVG1 1 0 /2 0 /3 3

WELD P (F /E )-UNADJUSTED-------------------------95%CI *ERR P(INITIA) N»V

1. FLAWS/H»»3

ADJUSTED-------P (F /E ) 3ERR

FO 1.090D+19

NTRIALS

4 .70D -06 1. 17D-06 7 .05D -06

4 .60D -06 9 8 .0 02 .3 0 D -0 6 196 .00 5 .6UD-06 8 0 .0 2

U.70D-06 0 .0 9 0 1 . 88D-07 5000001 .17D-06 0 .0 9 0 9 .7 0 D -0 8 5000007.05D-06 0 .0 1 0 7 .05D -08 500000

VESSEL 3 .05D -07 69.91

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 .7 1 9 .0 2 5 .9 38. 1 5 0 .8

NUMBER 0 3 5 1 2 0 0PERCENT 0 . 0 2 7 .3 9 5 .5 9 .1 1 8 .2 0 . 0 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 .0 9 0 .0 5 0 . 0 6 0 .0 7 0 . 0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 12 0 .0

NUMBER 0 0 0 0 0 0 0 0 0 1 3 7PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 9. 1 2 7 .3 6 3 .6

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 9 1 . 7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.1

NUMBERPERCENT

00 . 0

00 . 0

1 7 38 .3 5 8 .3 2 5 .0

18 .3

00 . 0

00 . 0

00 . 0

00 . 0

00 . 0

00 . 0

ARREST T-RTNDT (DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 .8 9 1 . 7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111. 1 125 .0 13 8 .9

NUMBERPERCENT

0 1 0 . 0 10 0 . 0

00 . 0

00 . 0

00 . 0

00 . 0

00.0

00.0

00.0

00.0

00.0

00 . 0

E -5

IPTS OCONEE CLflO TBVBl 1 0 /2 0 /8 3

0 .J o.a 0.3 0.4 0.Sfl/W

0.0 0.7 0.0 0.8

E -6

IPTS OCONEZ; CLSO T8V61 1 0 /2 0 /8 3

E -7

CRlTICflL CRfWK DEPTH CURVES FOR IPTS OCONEE OLflD TBVBl 1 0 /2 0 /8 3RTNDTO — 6 .7 DE»0 ZOU - 0 .2 9 ZNl - 0 .5 5 FO - l.OSEllS L0N6IT

O

d “

m

n

o0 30 30 40 SO 0010 70 80 90 100 110 12

T lfC (MINUTES)

E -8

TRANSIENT NO. 4 (TBVG4)

E-9

•b«

V!T

CM

CJ X ,

IPTS OCON0E CLRD T3VG4 1 0 /20 /33

oCD o LJ •a 8

P PRESS.(MPfl)o TEnP.(DEG.C.)A hTCfH/hNx2xK)

c0 .

• <n(OuOf0 .

0.0 10.0 20.0 x .o SO.O 00.0 70.0TIMEI^IIN.)

m o 110.0 120.0

E-10

IPTS OCONEE CU D TBVG4 1 0 / ’ 0/B3

WELD P (F /E )-UNADJUSTED-------------------------9 5 tC I tERR P(INITIA) N»V

1. FLAWS/M»»3

ADJUSTED------P (F /E ) tERR

FO r I .O 9OD+I9

MTRIALS

1 2 .7 2 D -0 2 2.1t2D-03 8 .9 0 2 .75D -02 0 .0 9 0 1 .09D -03 100002 1 .6 2 D -0 2 I . 33D-O3 8 . 2 3 1 .63D -02 0 .0 9 0 6 .97D -09 200003 2 .6 3 D -0 2 2 .3 8 D -0 3 9 .0 6 2 .67D -02 0 .0 1 0 2 .63D -09 10000

VESSEL 2 .OOD-O3 5 .6 6

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 .7 1 9 . 0 2 5 .9 38. 1 5 0 .8

NUMBER 3*18 725 295 89 23 9 0PERCENT 2 3 . 5 9 9 . 0 1 9 . 9 5 . 7 1 .6 0 . 3 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 . 0 9 0 .0 5 0 .0 6 0 . 0 7 0 . 0 8 0 .0 9 0 .0 100 .0 1 1 0 .0 12 0 .0

NUMBER 0 0 0 0 0 0 2 8 96 1 19 310 976PERCENT 0 .0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 1 0 . 5 3. 1 8. 1 2 1 .2 6 6 .8

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8

NUMBER 20 1 13 370 580 3*15 51 1PERCENT 1 .9 7 . 6 2 5 . 0 3 9 .2 2 3 .3 3 . 9 0 .1

9 1 . 7 5 5 . 6 6 9 .9 8 3 .3 9 7 .2 111.10 0 0 0 0

0 . 0 0 . 0 0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 13 . 9 2 7 .8 9 1 . 7 5 5 . 6 6 9 .9 8 3 .3 9 7 .2 111. 1 12 5 .0 138 .9

NUMBERPERCENT

00.0

00.0

736.8

1263.2

00.0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

E -11

IPTS OOWEE CLflD TBV84 1 0 /2 0 /8 3

E -1 2

IPTS OCONEE CLND TBV64 1 0 /2 0 /8 3

100 110 IS

E -1 3

CRITICflL CRflCK DEPTH OKVES FOR IPTS OCONEE CLflD TBVC4 1 0 /2 0 /8 3RTNDTO — 6 .7 DECC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N8IT1 1 1 i-T r 1 1 1 1 1 r 1 1 1 » ^ r » 1 » 1 B 1 r 1 1 »-i »■ t p » ............ . i > i ■ i | i , i , | i i i i

X a

X * H ♦

• X ^ n 8 -

BS

X *

° •* - X + B ♦

0

BB

♦X * □ # .

BB

B

♦ 0

> B B B B

B ■ B «•b

X , f - “ □ ♦....................... B ■

B ■ • X ^♦X 4> D «

X □ 0X + ♦

X ♦ D O 4 DO

X

oX

X BN c O

Bo.X

. . . . . . . . . . . ’ ' * * ‘ * * ’‘ ? ’' * * X ¥ x x ^ 8 ! P g a 8 a B 8 H B !

0 to ao 30 « so ao 70 ao 90 100 110 i: TIME(MINUTES)

E - 1 4

d -

TRANSIENT NO. 6 (TBVC36)

E -1 5

IPTS OCONEE CLflO TBVC6 1 /3 /8 4

od a ^ 8

o

□ PRESS, ( y f l )o TSflP. (DEC.C.lA HTC(H/hw2xK)

cc0.

• <o <r>UJQCCL

0.0 ».o x . o 40.0 50.0 eo.o 70.0TIM EtniN.)

ao.o 90.0 100.0 a o .o i x . o

E -1 6

IPTS OCONEE CLAD TBVG6 W 3/SH

----------------------- UNADJUSTED-----WELD P (F /E ) 95<CI »ERR P(IN ITIA ) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) tERR

FO = 1.090D+19

NTRIALS

1 2 .23D -05 1 .00D -05 U4.96 9 .35D -05 O.QltO 8 .93D -07 5000002 1 .29D -05 7.6AD-06 59 . 10 1 .88D -05 O.OUO 5 . 17D-07 5000003 2 .5 8 0 -0 5 1 .08D -05 4 1 .7 9 3 .2 9 0 -0 5 0 .0 1 0 2 .5 8 0 -0 7 500000

VESSEL 1 .6 7 0 -0 6 30 .9 3

DEPTHS FOR INITIAL INITIATION (MM)3 .2 6 . 3 1 2 .7 1 9 .0 2 5 .4 3 8 .1 5 0 .8

NUMBER 2 43 17 10 7 2 0PERCENT 2 . 5 53. 1 3 1 .0 1 2 .3 8 .6 2 . 5 0 . 0

TIMES OF FAILURE(MINiriESI0 . 0 1 0 .0 2 0 .0 3 0 .0 4 0 .0 5 0 .0

NUMBER 0 0 0 0 0 0PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0

6 0 . 0 7 0 .0 8 0 .0 9 0 . 0 1 0 0 .0 110 .0 1 2 0 .0 0 3 10 7 14 18

0 . 0 5 . 8 1 9 .2 1 3 .5 2 6 .9 3 4 .6

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 4 1 .7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111.1

NUMBER 0 0 1 5 37 29 1 4 1 0 0 0 0PERCENT 0 . 0 0 . 0 1 7 .2 4 2 .5 3 3 .3 1. 1 4 . 6 1. 1 0 . 0 0 . 0 0 . 0 0 .0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 4 1 .7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111. 1 125 .0 138 .9

NUMBERPERCENT

25 .7

144 0 .0

1337 .1

00.0

00.0

00.0

00.0

41 1 .4

25 . 7

00.0

00.0

00.0

E -1 7

00

tem

p. DE

CC,

aoo

too13

5IT

S33

5ST

S30

033

5

o>

IPTS OCONEE CLflD TBV86 1 /3 /8 4

E -1 9

CRITICflL CRflCK DEPTH CUR'/E3 FOR IPTS OCOICE CLflD TBV06 1 /3 /8 4RTNDTO — 6 .7 KMC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 LONOIT

230

* 5 < X X X X X X X X X X X X X

ao too 110 i:60 70 600 20 30 so10TIME(MINUTES)

E -2 0

TRANSIENT NO. 7 (TBVG7)

E -21

IPTS OCONEE CLflO T3VQ7 1 0 /2 0 /8 3

Xa oa

o

n PRESS.(HPfl>o TEfip. (oec,c.)A HTC(H/Hx«2xK)

m .o 110.0 lao.o00.0 90.0S0.0 70.020.0 40.0 00.00.0 10.0

• <n(O

TIMEtMIN.)

E-22

IPTS OCONEE CUD TBVG7 1 0 /2 0 /8 3

WELD P (F /E )-UNAOJ'JSTED-------------------------9 5 tC I %ERR P(INITIA)

1. FLAWS/M' S ADJUSTED-------

P (F /E ) tERR

FO 1. 0900+19

NTRIALS

1 8 .1 ID-05 1 .91D-05 2 3 .5 9 9 .2 8 0 -0 5 0 .0 9 0 3 .29D-06 5000002 2 .9 9 0 - 0 5 1. 150-05 3 9 .2 0 3. 17D-05 0 .0 9 0 1. 170-06 5000003 8 .9 6 0 -0 5 1 .9 5 0 -0 5 23. 10 8 .6 9 0 -0 5 0 .0 1 0 8 .9 6 0 -0 7 500000

VESSEL 5 .2 6 0 -0 6 17 .3 7

DEPTHS FOR INITIAL INITIATION (MH)3 . 2 6 . 3 1 2 .7 1 9 .0 2 5 .9 38. 1 5 0 .8

NUMBER 6 82 93 31 15 3 0PERCENT 3 . 3 9 5 .6 2 3 .9 1 7 .2 8 .3 1 .7 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 .0 9 0 .0 5 0 . 0 6 0 . 0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 120 .0

NUMBER 0 0 0 0 1 9 8 18 23 30 39 98PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 6 2 . 9 9 . 8 1 0 .8 1 3 .9 18. 1 2 0 .5 2 8 .9

INITIATION T-RTNOT(OEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 9 1 . 7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.1

NUMBER 0 1 16 56 89 22 1 0 0 0 0 0PERCENT 0 . 0 0 . 6 8 . 9 31. 1 9 6 .7 1 2 .2 0 . 6 0 . 0 0 . 0 0 . 0 0 . 0 0 .0

ARREST T-RTNOT(OEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 13 .9 2 7 .3 9 1 . 7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111. 1 12 5 .0 138 .9

NU8BERPERCENT

00.0

21 9 .3

128 5 .7

00.0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

E-23

IPTS OCONEE CLflD TBV87 1 0 /2 0 /8 3

I : '

E -2 4

IPTS OCOfCE CLflD TBV87 1 0 /2 0 /8 3

E -2 5

CRITICflL CRflCK nEPTri Cl^VES FOR IPTS OCONEE CLfffl TB787 1 0 /2 0 /8 3RTNDTO — 6 .7 DEBC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N6IT

me

ma

Ke

«ee

ind

d

K)d

nd

d

oao 110 i:0 « so ao 70 8010 30 30

i:

T IfE (MINUTES)

E -26

TRANSIENT NO. 10 [TBVGIQ(TBVGO)]

E-27

*b ot S-

r j -

Sr.CM

E P-

OX I

IPTS OCONEE CLnO 13700 1 /3 /8 4

oCS o0 8a.EU1

D PRESS.(NPRlo TEnP.(DEG.C.lA HTCiy/>1i<*2*K)

100.0 liO.O 120.000.0 90.030.0 SO.O 70.00.0 20.0 40.0 60.010.0

Q-oE

TIME(MIN.]

E -2 8

IPTS OCONEE CLAD TBVGO 1 /3 /B 4

WELD P (F /E )-UNADJUSTED-------------------------95».CI tERR P(INITIA) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) tERR

FO = I .O 9OD+I9

NTRIALS

1 . 1I6D-09 6 . 96D-05 1. lt1D-09

2 .5 6 0 -0 5I . 7 ID-O52 .52D -05

17 .6026 .9 317 .89

2 .06D -099 .6 3 0 -0 51 .9 6 0 -0 4

0 .0 4 0 5 .8 3 0 -0 60 .0 4 0 2 .58D-060 .0 1 0 1 .4 1 0 -0 6

VESSEL 9 .8 2 0 -0 6 12.81

500000500000500000

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 . 0 2 5 .4 38. 1 5 0 .8

NUMBER 24 265 64 43 24 4 0PERCENT 5 . 7 6 2 .5 15. 1 10. 1 5 . 7 0 . 9 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 10 . 0 20 .

NUMBER 0 0PERCENT 0 .0 0 . 0

0 3 0 . 0 4 0 .0 5 0 .0 6 0 .0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 10 .0 120 .00 0 0 5 23 71 63 61 42 34

0 . 0 0 . 0 0 . 0 1 .7 7 . 7 2 3 .7 21 . 1 2 0 .4 1 4 .0 1 1 .4

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 .8 41,

NUMBER 0 0 30 180 172 63 106PERCENT 0 .0 0 . 0 5 . 1 3 0 .9 2 9 .5 1 0 .8 1 8 .2

7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111.132 0 0 0 0

5 .5 0 . 0 0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 13 .9 0 . 0 13 . 9 2 7 .8 4 1 . 7 5 5 .6 6 9 .4 83. 3 9 7 .2 111. 1 125 .0 138 .9

NUMBERPERCENT

10 .4

501 7 .6

451 5 . 8

6 2. 1

00.0

00.0

41 .4

842 9 . 6

9433.1

00.0

00.0

00.0

E-2 9

IPTS OCONEE CLfln TBVeO 1 /3 /8 4

E -3 0

IPTS OCONEE CLflD TBV60 1 /3 /8 4

E -31

CRITICflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLflO TBVBO 1 /3 /8 4RTNOTO — 6 .7 DECC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N6IT

md •fO

d

K.d

«od

if»a

d

r>d

rfd

d

^ X X X X X X X X X X X X X X X X M W X X X X X X X X X X X X Xa

100 110 i:00 70 00 90« so0 10 ao 30TIME(MINUTES)

E -3 2

TRANSIENT NO. 14 (PSBG4)

E -3 3

0.02.0

I

_4.

0^

I.

0.0

—L

-*.

0.0

10.0

12.0

14.0

10.010.

0»

-Ml

Cf20

.0

TEM

P.(D

EC.C

.)

U)

330.

030

0.0

240.

02T

0.021

0.0

ISD.

O10

0.0

00.0

00.0

».0

•-1 u> o

X

20.0

10.0

14.0

10.0

b 0

.012.

00.0

10.0

PRES

S. (M

PR)

0.02.0

4.0

IPTS OCONEE CUD PSBG4 1 0 /2 0 /8 3 1. FLAWS/M» *3 FO = 1.090D+19

WELD P (F /E )—UNADJUSTED-------------------------95*CI tERR P(INITIA) N«V

ADJUSTED-------P (F /E ) tERR NTRIALS

1.59D-02 1. 13D-02 1 .65D -02

1 .32D-03 9 . 12D-0a 1 .39D-03

8. 30 8 .0 9 8. 16

1 . 72D-02 1 . 25D-02 1 . 73D-02

0 .0 9 00 .0 9 00 . 0 1 0

6. 38D-09 9 .51D-09 1 .65D-09

200003000020000

VESSEL 1.25D-03 5 .2 9

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 .0 2 5 .9 38. 1 5 0 .8

NUMBER 376 1099 255 99 33 5 0PERCENT 2 0 .8 5 7 .9 19. 1 5 . 2 1 .8 0 . 3 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 .0 9 0 .0 5 0 .0 6 0 . 0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 1 2 0 .0

NUMBER 0 0 0 0 0 19 191 370 912 373 235 135PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 8 8 . 9 2 2 .0 2 9 .5 2 2 . 2 1 9 .0 8 .0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 9 1 .7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.1

NUMBER 0 28 929 783 996 172 507 175 3 0 0 0PERCENT 0 . 0 1. 1 1 6 .9 3 0 .3 1 9 .2 6 . 6 1 9 .6 6 . 8 0 . 1 0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 9 1 .7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111. 1 125 .0 138 .90 . 0 1 3 .9 2 7 .8

NUMBER 5 31 50 20 1 0 19 262 523 2 0 0PERCENT 0 . 6 3 . 9 5 . 5 2 . 2 0 .1 0 . 0 1 . 5 2 8 .9 5 7 . 6 0 . 2 0 . 0 0 . 0

E -3 5

IPTS OCONEE CLflO PSBC4 10/20/83

0.1 o.a 0.3 0.4 0.5n/u 0.0 0.7 0.8 0.S

E -3 6

IPTS OCONEE CLflO PSB84 10/20/83

E -3 7

CRITICflL CRflCK DEPTH 0«V E S FOR IPTS OCONEE CLfiO PS8C4 1 0 /2 0 /8 3RTNDTO — 6 .7 DEOC %CU - 0 .2 9 XNI - 0 .5 5 FO - 1.09E19 L0N6IT

■ P F f 1 1 0 1 0 1 1 0 » ■ 1 * '

X

r 1 F r F r 1 r F F F' r r > F r p p f r t y - f f ppp r p f | p » r

B

01e »2ao \ X

Xm «♦

X + B

md X # D «

X + «

+ ♦KO

X

♦

«»e

• • •r* • • • X

+

♦ a ♦ ♦

• ♦ ••

•* • * .

X+ 0

..........................« .......................

d•• X t ..............................

□ 0

r>e

♦□ «

a 0a

\ X *♦

nd

+!>

X 'D

a□

d X'X

’ □a

a ,0 fc h 0 1 i 1 1 1 1 i 1 1 0 1 . 7 y 7 c ” g ) n 8 S 8 S 5 a ! i ( S S 9 3 9 a B 9 B 9 a 9 S 8 9 a 8 B S 8 9 8 !

to so 00 70TIMEtMINUTESl

too ito

E—38

TRANSIENT NO. 21 [ FW6( 0VRFD6) ]

E -3 9

0.0I__ _

2.0 4.0- J _

6.0 I.

HTC(W/M><m2kK) 0 .0 10.0 12.0 14.0 16.0

I L_._10.0

I 1 i20.0

TE?1P. (DEG.C.)

r*O

330.0240.0 2ro.o 300.030.0 90.0 120.0 ISO.O 213.0po

oo

bb O

b8o

Om8oZ.

o

8b8b

•Hn8bpb O

5 1—b 0.0 0.0 10.02.0 4 .0 0.0 10.0 14.0PRESS. (flPR)

IPTS OCONEE CUD FW6 1 1 /1 0 /8 3

WELD P (F /E )-UNADJUSTED-------------------------95JC I %ERR P(INITIA) N»V

1 . FLAWS/M»«3

ADJUSTED-------P ( F /E ) %ERR

FO = I .O 9OD+I9

NTRIALS

1.53D-05 3 .52D-06 1 . 76D-D5

8 . 3OD-O6 5 9 .3 63 .99D -06 113. 16 8 .92D -06 50.61

1 .6 9 0 -0 5 0 .0 9 0 6. 1 ID- 0 7 5000003 .52D -06 0 .0 9 0 1 .9 1 0 -0 7 5000001 ,7 6 0 -0 5 0 .0 1 0 1 .7 6 0 -0 7 500000

VESSEL 9 .28D -07 90 .8 9

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 .7 1 9 . 0 2 5 .9 38. 1 5 0 .8

NUMBER 1 11 13 9 3 0 0PERCENT 3 . 1 3 9 . 9 9 0 .6 1 2 .5 9 . 9 0 . 0 0 , 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 . 0 9 0 .0 5 0 . 0 6 0 .0 7 0 . 0 8 0 ,0 9 0 .0 1 0 0 .0 11 0 .0 120 .0

NUMBER 0 0 0 0 0 0 0 0 0 0 5 26PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 16. 1 83 .9

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 .8 9 1 .7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.1

NUMBER 0 0 0 9 23 5 0 0 0 0 0 0PERCENT 0 . 0 0 . 0 0 . 0 1 2 .5 7 1 .9 1 5 .6 0 . 0 0 . 0 0 . 0 0 .0 0 . 0 0 .0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 13 . 9 2 7 . 8 9 1 .7 5 5 . 6 6 9 .9 8 3 .3 9 7 .2 111. 1 12 5 .0 13 8 .9

NUMBERPERCENT

00.0

0 1 0 . 0 10 0 . 0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

00.0

E -41

IPTS OCONEE CLflO FV» 1 1 /1 0 /8 3

H

.8

R

8

§

R0 0.1 0 .3 0 .3 0 .4 0 .5 0.6 0.7 0.6 0 .9 1n/w

E-M2

CLflD FM6 1 1 /1 0 /8 3

E -4 3

CRITICfiL CRflCK DEFTri CUR'/ES FOR IPTS OCONEE CLflD FW6 1 1 /1 0 /8 3RTNDTO — 6 .7 DECC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N6IT

n

100 n o i:70 00 9040 SO 000 ao 3010TIME(MINUTES)

E-4H

TRANSIENT NO. 24 [ZITBV(ZPITBV)]

E -4 5

•b o

XrgTE r \ ‘ 3O

IPTS OCONEE CLflD 21TBV 10/20 /33

C J

C9 o

5^8-

o PRESS.(MPfl)o TEMP.(PEG.0.1A HTCtW/N>o<2xK)

so.o0.0 10.0 20.0 30.0 10.0 60.0 70.0 80.0 90.0 i n . o ;;o .o i 20.o

cc0.

• (O<nuft:0.

TIME(MIN.)

E -4 6

IPTS OCONEE CLAD Z 1TBV 1 0 /2 0 /8 3

WELD P (F /E )-UNADJUSTED-------------------------95*CI %ERR P(INITIA) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) tERR

FO I .O 9OD+I9

NTRIALS

1 I . 5 ID-O3 1 .9 6 0 -0 4 9 .6 9 I . 6OD-O3 0 .0 9 0 6 .05D-05 1600002 6 .98D -09 6 . 9OD-O5 9 .8 9 7 .99D -09 0 .0 9 0 2 .79D-05 3300003 1 .65D -03 1 .63D-09 9 .8 7 1 .79D -03 0 .0 1 0 1 .65D-05 190000

VESSEL 1.05D-09 6 .3 5

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 . 0 2 5 .9 38. 1 5 0 .8

NUMBER 83 702 283 133 51 15 2PERCENT 6 . 5 5 5 .3 2 2 .3 1 0 .5 9 . 0 1 . 2 0 . 2

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 . 0 9 0 .0 5 0 . 0 6 0 .0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 110 .0 1 2 0 .0

NUMBER 0 9 2 31 116 1 12 165 135 159 180 126 167PERCENT 0 . 0 0 . 8 0 . 2 2 . 6 9 . 7 9 . 9 1 3 .8 1 1 .3 1 2 .9 1 5 .0 1 0 .5 1 9 .0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

00.0

20.2

1301 0 . 2

0 . 0 1 3 . 9 2 7 . 8 9 1 .7 55. 6 6 9 .9 83. 3 9 7 .2 111.1983

3 7 .8519

9 0 .3129

10. 117

1 .32

0.20

0.00

0.00

0.00

0.0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

22 .5

172 1 .3

0 . 0 1395

5 6 .3

9 2 7 . 8 9 1 .7 5 5 . 6 6 9 .9 8 3 .3 9 7 .2 111. 1 125 .0 138 .910

1 2 .51

1 .30

0.00

0.01

1 .39

5 .00

0.00

0.00

0.0

E-47

IPTS OCONEE CLflD 21TBV W / 2 0 /8 3

0.1 0.2 0 .3 0 .4 0 .Sfl/H 0.6 0 .7 0.8 0.6

E-i|8

IPTS OCONEE CLflO ZITBV 1 0 /2 0 /8 3

E -4 9

CRITICflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLflD ZITBV 1 0 /2 0 /8 3RTNDTO — 6 .7 DECC ZCU - 0 .2 9 ZNI - 0 .5 5 FO - 1 .09E 19 LONCIT

01d

md

Is.d

IDd

lAd

•0d

n O#d

d

• B D D O B O n o n O B O a D D«XScXXXXXXx

X X X X K X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

X ’ X '

o9030 40 so 90 70 80 100 110 IS0 10 ao

TIME(MINUTES)

E -5 0

TRANSIENT NO. 25 [Z2TBV(ZP2TBV)]

E -51

0.0I -

2.0 4.0■ i i

e .oHTC(W/Mn« 2 mK)

8.0 10.0 12.0 14.0 16.0I__

18.0I U-.-

Hicf20.0

TEflP. (DEQ.C.)

PKJ\ro

300.3 330.090.3 ISO.O 180.0 219.330.0 120.0

‘0O)oCD

PIPJo

PJCOCO

o P I

ap)

o

b 0.0 8.0 12.0 14.0 16.02.0 4.0 6.0 10.0PRESS.(MPfl)

IPTS OCONEE CLAD Z2TBV 10/?0/R3

WELD P (F /E )-UNADJUSTED-------------------------95%CI JERR P(INITIA) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) %ERR

FO I .O 9OD+I9

NTRIALS

6.84D-03 It. I 9D-O3 7 .55D -03

6. 180-04 3 .9 6 0 -0 4 6. 480-04

9 .0 3 9. 44 8 .5 9

6 .9 5 0 -0 34 . 3ID-037 .5 9 0 -0 3

0 .0 4 0 2 .74D-040 .0 4 0 1 .68D-040 .0 1 0 7 .55D-05

400006000040000

VESSEL 5. 170-04 5 .81

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 . 0 2 5 .4 38. 1 5 0 .8

NUMBER 187 751 319 129 34 10 0PERCENT 13.1 5 2 .5 2 2 .3 9 . 0 2 . 4 0 . 7 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 10 .0 2 0 .0 3 0 . 0 4 0 .0 5 0 .0 6 0 .0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 120 .0

NUMBER 0 78 23 171 228 187 205 146 124 98 63 85PERCENT 0 . 0 5 . 5 1 .6 12. 1 1 6 .2 1 3 .3 1 4 .6 1 0 .4 8 .8 7 . 0 4 .5 6 .0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 .8 - 1 3 . 9 0 . 0 1 3 . 9 2 7 . 8 4 1 .7 5 5 .6 6 9 .4 83. 3 9 7 .2 111.1

NUMBERPERCENT

00.0

30.2

117 8. 1

49534.1

5834 0 .2

219 15. 1

322.2

30.2

00.0

00.0

00.0

00.0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3. 9

NUMBERPERCENT

00.0

0 .0 13 . 9 2 7 .8 4 1 .7 5 5 .6 6 9 .4 83. 3 9 7 .2 111. 1 125 .0 138 .9

18.2 1431 . 8

36.8

00.0

00.0

12 . 3

613 . 6

122 7 .3

00.0

00.0

00.0

E-53

IPTS OCONEE CLflO Z2TBV 10/20/83

E-5H

IPTS OCONEE CLflD Z2TBV 1 0 /2 0 /8 3

E -5 5

CRITICflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLflD Z2TBV 1 0 /2 0 /8 3RTNDTO — 6 .7 DE6C XCU - 0 .2 9 XNI - 0 .5 5 FO - 1.09E19 LONCIT

• a

XX

XXX

10X C

XX

X

X B

D

++

0O

fa -

+ . • *

&

D d

x:yxxxxyxxxxyxxxxyxxx5ggS8gS8!j!gg8SgggSgggg8ggg!j!8gggg

• •••

>w

20 10 SO 60 70TIME(MINUTES)

80 100 110

E -56

TRANSIENT NO. 26 (MSLB1)

E -5 7

•boxS-1

XOJ X - X ‘

IPTS OCONEE CLflD fISLBl 1 0 /2 0 /8 3

oC9 a

^8-a.r.u

o PRESS.(NPfl)o TEMP.(PEG.C.)A HTC(i /MNi<2xK)

• <n <ohj£

0.0 iO.D 20.0 30.0 40.0 SO.O 60.0 70.0TIME(MIN.)

80.0 90.0 lOO.O 110.0 120.0

E-58

IPTS OCONEE CLAD MSLB1 1 0 /2 0 /8 3

WELD P (F /E )-UNADJUSTED-------------------------9 5 tC I *ERR P(INITIA) N»V

1 . FLAWS/M»»3

ADJUSTED-------P (F /E ) tERR

FO I . O 9 OD+I9

NTRIAU?

1 8 . 56D-O3 7 .9 6 0 -0 9 9 . 31 3. 160-02 0 .0 9 0 3 .92D -09 3OOOO2 9 . 7OD-O3 9 .59D -09 9 .7 6 2 . 03D- 0 2 0 .0 9 0 1 .8 8 0 -0 9 500003 8 .9 5 0 - 0 3 8. 190-09 9 .1 0 3 .3 6 0 -0 2 0 .0 1 0 8 .9 5 0 -0 5 30000

VESSEL 6 .2 0 0 -0 9 6 .0 8

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 .7 1 9 . 0 2 5 .9 38. 1 5 0 .8

NUMBER 2507 1817 605 120 19 1 0PERCENT 9 9 . 5 3 5 .9 1 1 .9 2 . 9 0 . 3 0 . 0 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 . 0 9 0 .0 5 0 .0 6 0 . 0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 120 .0

NUMBER 0 0 990 753 91 6 9 0 0 0 0 0PERCENT 0 . 0 0 . 0 3 7 .9 5 8 . 2 3 . 2 0 . 5 0 . 3 0 . 0 0 . 0 0 . 0 0 . 0 0 .0

INITIATION T-RTNOT(OEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

0 . 0 1 3 . 9 2 7 . 8 9 1 .7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.11

0.013

0.22839 .7

13892 2 .9

22003 6 .3

108517.9

6971 1 .5

3796.2

220 .9

00.0

00.0

00.0

ARREST T-RTNOT(OEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

00.0

0 . 0 13 . 9 0 0 1

0 . 0 0 . 0 0 . 0

2 7 .8 9 1 . 7 5 5 . 6 6 9 .9 8 3 .3 9 7 .2 111.1 125 .0 138 .92 1 97 1269 3295 176 0 29

0 . 0 0 . 0 1 .0 2 6 .6 6 8 .0 3 .7 0 . 0 0 .6

E-59

IPTS OCONEE CLflO MSLBl 10/20 /83

E -6 0

IPTS OCONEE CLflO 10/20/83

E -61

CRITICflL CRfWaC rePTH CURVES FW IPTS OCONEE CLflO HSLBl 1 0 /2 0 /8 3RTNDTO — 6 .7 DE8C XCU - 0 ,2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N6IT

^ • 1 • • '•

•

•

•

••

•

•

••

• ••

• • '

•

•

••

••

• •• •

-X X

X X

Xik > 4 * ^ X

+

¥* » •*c

XX $

$ XX O j XX iP t a X

...........................................................................................................................................................10 so 00 70

TIME(MINUTES)100 110 12

E -6 2

TRANSIENT NO. 28 (MSLB3)

E -6 3

IPTS OCONSE CLflD MSLB3 1 0 /2 0 /8 3

V.T OOJ* _ CS oxH' uj):•r: cj-j o 8-3 • .

Q_r:o“CD

a PRESS.(MPR)o TEflP. (DE6.C.)A hTC(W/Hx>«2xK)

<N“

CL.. r:

• CO<nCiJor.CL.

0 .0 10.0 20.0 30.0 40.0 50.0 60 .0 70.0TIME(MIN.)

80.0 90.0 100.0 110.0 120.0

E -6 4

IPTS OCONEE CLAD MSLB3 1 0 /2 0 /S 3

WELD P (F /E )-UNADJUSTED----9 5 tC I tERR P(IN ITIA ) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) <ERR

FO I .O 9OD+I9

NTRIALS

5. 3OD-O3 3. 17D-03 6 . 36D-O3

9.87D-0«2.98D-Olt5.96D-OU

9. 19 9 . 40 9 .3 7

3.28D -02 1 . 94D-02 3 .98D -02

0 .0 4 0 2 . 12D-040 .0 4 0 1 .27D-040 .0 1 0 6 .3 6 0 -0 5

VESSEL 4.02D-04 5 .8 7

500008000040000

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 .0 2 5 .4 38. 1 5 0 .8

NUMBER 4126 2668 847 143 14 1 0PERCENT 5 2 . 9 S'*.2 1 0 .9 1 .8 0 . 2 0 . 0 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 10 .0 2 0 .0 3 0 . 0 4 0 .0 5 0 .0

NUMBER 0 100 1051 156 7 1PERCENT 0 . 0 7 . 6 7 9 .9 1 1 .9 0 . 5 0 .1

6 0 . 0 7 0 . 0 8 0 . 0 9 0 . 0 1 0 0 . 0 110 .0 1 2 0 . 0 1 0 0 0 0 0

0 . 1 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 .9 0 . 0 1 3 . 9 2 7 . 8 4 1 .7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111.1

NUMBERPERCENT

10 . 0

390 .5

421 5. 1

21112 5 .4

33484 0 .3

16792 0 . 2

4004 . 8

3043 .7

130 . 2

00 . 0

00 . 0

00 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 13 . 9 0 . 0 13 . 9 2 7 . 8 4 1 . 7 5 5 . 6 6 9 .4 8 3 .3 9 7 .2 111. 1 125 .0 138 .9

NUMBERPERCENT

00.0

00.0

00.0

00.0

10.0

20.0

440.6

14402 0 . 6

51387 3 .4

3735 .3

00.0

20.0

E -6 5

IPTS OCONEE CLflO MSLB3 10/20/83

E -6 6

IPTS OCONEE CLflO MSLB3 10/20/83S

8

8

N9*

R0 10 ao 30 40 so 60 70 80 90 100 110 i:TIME

E -6 7

CRITICflL CRACK DEPTH CURVES FOR IPTS OCONEE CLflO MSLB3 lC /2 0 /8 3RTNDTO — 6 .7 DECC %CU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 L0N6IT

ata

d

INd

«0d

ind

d * *

• 5*d

+ 3? + Xnd

R o §

o 1!90 100 1X000 70 8030 40 SOao0 10TIME(MINUTES)

E -6 8

TRANSIENT NO. 29 (MSLBil)

E -6 9

om 8“

E o -V. ^

IPTS OCONEE CLAD MSLB4 1 0 /2 0 /8 3

C9 o LJ •5 8

□ PRESS.(hPfl)o TEHP.(DEG,C.)A HTC( /hxN2xK)

CL

(nuQ_

iO.O 20.0 30.0 40.0 50.0 60 .0 70.0TIME(MIN.)

90.0 loc.o n o .o 120.0

E-70

IPTS OCOMEE CLAD MSLBU 1 0 /2 0 /8 3

WELD P (F /E )— UNADJUSTED-------------------------

95*01 *ERR P(IN ITIA ) M»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) *ERR

FO = 1 . 0 9 0 D + 1 9

NTRIALS

1 3 .98D -02 2 .89D -03 7 .2 7 4 .7 9 D -0 2 0 .0 4 0 1 .59D -03 100002 2 .3 5 D -0 2 2 .26D -03 9 .6 0 3. 1 ID-02 0 .0 4 0 9 .40D-04 100003 4 .14D -02 2 .95D -03 7 . 12 5. 13D-02 0 .0 1 0 4 . 14D-04 10000

VESSEL 2 .95D -03 5 .0 8

DEPTHS FOR INITIAL INITIATION (MH)3 . 2 6 . 3 1 2 .7 1 9 .0 2 5 .4 38. 1 5 0 .8

NUMBER 1137 757 259 50 13 2 0PERCENT 5 1 .3 34. 1 1 1 .7 2 . 3 0 . 6 0 . 1 0 . 0

TIMES OF FAILURE(MINUTES)0 . 0 10 .0 2 0 .0 3 0 .0 4 0 .0 5 0 .0

NUMBER 0 0 536 421 183 211PERCENT 0 . 0 0 . 0 30. 1 2 3 .6 1 0 .3 1 1 .8

6 0 . 0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 1 1 0 .0 120 .0320 94 17 1 0 0

1 7 .9 5 . 3 1 . 0 0 . 1 0 . 0 0 .0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 41,

NUMBER 0 22 171 610 977 810 854PERCENT 0 . 0 0 . 6 4 . 6 1 6 .3 26. 1 2 1 .6 2 2 .8

7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111. 12927 .8

80 . 2

00 . 0

00 . 0

00 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 . 8 4 1 .7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111. 1 125 .0 138 .9

NUMBERPERCENT

00 . 0

00 . 0

00 . 0

00.0

00 . 0

11 0 . 6

4272 1 . 8

14517 4 .0

55 00 . 0

150 . 8

E -71

IPTS OCOKEE CLflD MSLB4 10/20/83

E-72

IPTS OCONEE CLflD MSLB4 1 0 /2 0 /8 3

E-73

CRITICflL CRflCK OCPTH CURVES FOR IPTS OCOCE CLflO NSLB4 lO m /8 3RTNDTO — 6 .7 OEOC ZCU - 0 .2 9 %NI - 0 .5 5 FO - 1.09E 19 LONBIT

9f •

I

n

+ •♦x«0

ao 30 « ao • 7D n0 10 n too 110 ISTINE(HINUTES)

E-74

TRANSIENT NO. 33 [W1TBV(ZW1TBV)]

E-75

'boIr.

r.(M

IPTS OCONEE CLFID WITBV U / 0 4 / 8 3

oC9 o

9 8r:

~iO□ PRESS. tMPR)o TEMP.(PEG.C.)A HTCrW/!i?<M2xK)

a:a.. x:* <n (o

LJa.

20.0 SO.O 60.0 70.0TIMECMIN.)

E -7 6

IPTS OCONEE CUD WITBV 1 1 /0 4 /3 3

WELD P (F /E )-UNADJUSTED-------------------------95SCI tERR P(INITIA) N»V

1. FLAWS/M»«3

ADJUSTED-------P (F /E ) tERR

FO = I .O 9OD+I9

NTRIALS

8.48D-035.44D-039 . 3OD-O3

4. 14D-04 2.67D-04 4 .54D-04

4 .8 8 4.934 .8 9

8 . 68D- 035.63D-039.48D-03

0 .0 4 0 3. 39D-040 .0 4 0 2 .18D-040 .0 1 0 9 .3 0 0 -0 8

110000 170000 100000

VESSEL 6 .50D -04 3. 11

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 12 .7 19 . 0 2 5 .4 38. 1

NUMBER 689 2571 994 440 150 21PERCENT 1 4 .2 5 2 .8 2 0 .4 9 .0 3. 1 0 .4

5 0 .82

0.0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 20

NUMBER 0 16 9PERCENT 0 . 0 0 . 3 0 . 2

3 0 . 0 4 0 .0 5 0 .0 6 0 .0 7 0 .0 8 0 .0 9 0 .0 100 .0 1 1 0 .0 1 2 0 .072 195 343 484 603 661 704 780 880

1 .5 4 .1 7 . 2 1 0 .2 1 2 .7 1 3 .9 1 4 .8 16 .4 1 8 .5

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 .8

NUMBER 2 155 988PERCENT 0 . 0 3 . 2 2 0 .2

- 1 3 . 9 0 . 0 13 . 9 2 7 .8 4 1 . 7 5 5 .6 6 9 .4 8 3 .3194839 .9

143329.3

3286 .7

240 .5

5 0. 1

00.0

00.0

00.0

9 7 .2 111.1 0

0.0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

10 .7

181 3 . 2

0 . 0 13 81

5 9 .6

9 2 7 .8 4 1 .7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111. 1 125 .0 138 .925

18 .40

0.00

0.00

0.00

0.011

?. 10

0.00

0 . 00

0.0

E-77

Co

100

13S

ISOIT

Saa

s30

0

at

IPTS OCONEE CLflD HITBV 11/04/83

E-79

CRITICflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLflD WITBV 1 1 /0 4 /8 3RTNDTO — 6 .7 DECC XCU - 0 .2 9 ZNI - 0 .5 5 FO - 1 .09E 19 LONCIT

X ’X

XX

X

X

++

□a

•f □

o

Q

□O

X

X

X

■ •fX

» • *

9

'

♦

XX-f

*»oBn' ^T’‘’‘’***?^’‘^?>‘=*>=’‘?i<yy>tyxxxxyxxgg§SS!jiB!i!gggg8gg!j!g8g8!j!!j!

10 ao 50 eo 70 TIME(MINUTES)

90 100 110

E -8 0

TRANSIENT NO. 34 [W2TBV(ZW2TBV)]

E -81

IPTS OCONEE CLRD H2T3V 11 /0 4 /8 3

oOJ

o .o cLJ

p PRESS.(HPfl)o TEHP.(DCG.C.)A HTC(W/Mx>* )

"cJ

• tn (nLJora.

0.0 ao.o 30.0 40.0 S0.0 60.0 70.0TIMEtfllN.)

80.0 90.0 ioo.o lio.o 120.0

E -8 2

IPTS OCONEE CLAD W2TBV 1 1 /0 4 /8 3

WELD P (F /E )-UNADJUSTED-------------------------95%CI %ERR P(IN ITIA ) N»V

1, FLAWS/H»»3

ADJUSTED-------P ( F /E ) tERR

FO = I .O 9OD+I9

NTRIALS

2 .35D -02 1 .53D -02 2 . 40D-02

2 . 26D-03I . 3OD-O32.28D -03

9 .6 08 .4 79 .5 0

2 . 37D-02 1 .54D -02 2 .46D -02

0 .0 4 0 9 .40D -040 .0 4 0 6 . 12D-040 .0 1 0 2 .40D -04

100002000010000

VESSEL 1 .7 9 0 -0 3 5 .9 5

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 .7 1 9 . 0 2 5 .4 38 . 1 5 0 .8

NUMBER 240 731 256 89 29 4 0PERCENT 1 7 .8 5 4 . 2 1 9 .0 6 . 6 2 . 1 0 . 3 0 . 0

TIMES OF FAILURE (MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 . 0 4 0 .0 5 0 . 0

NUMBER 0 31 25 90 138 146PERCENT 0 . 0 2 . 3 1 . 9 6 . 8 1 0 .4 1 1 .0

6 0 . 0 7 0 . 0 8 0 . 0 9 0 . 0 1 00 . 0 1 10 . 0 120 . 0 171 170 173 146 122 117

1 2 .9 1 2 .8 1 3 . 0 1 1 . 0 9 . 2 8 .8

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 .8

NUMBER 0 37 226 541 429 108 18PERCENT 0 . 0 2 . 7 1 6 .6 3 9 .7 3 1 .5 7 . 9 1 .3

4 1 . 7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111.12 1 0 0 0

0 . 1 0 . 1 0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

00.0

0 . 0 13 . 9 2 7 . 8 4 1 . 7 5 5 .6 6 9 .4 8 3 .3 9 7 .2 111. 1 125 .0 13 8 .91

3 . 015

4 5 .54

12. 11

3 .00

0.00

0.03

9.19

2 7 .30

0.00

0.00

0.0

E -8 3

IPTS OCONEE CLflD H2m/ 11/04/83

0.1 0.2 0 .3 0 .4 0 .5fl/W

0.0 0.7 0.0 0.0

E-8lf

IPTS OCONEE CLflD H2TBV 11/04/83

E-85

CRITlCflL CRflCK CCPTH CURVES FOR IPTS OCONEE CLRD U2TBV 1 1 /0 4 /8 3RTNDTO — 6 .7 OEOC m i - 0 .2 9 %NI - 0 .5 5 FO - 1 .09E 19 L0N6IT' ' ' ' 1 • • » ' 1 1 a 9 1 I a-fa- a y r-a» f t r i i t-1 a i i-t-| i i a-a , , r-f » | » -a i i | i- i i f ,■

’ X Dmd ■ a

OX a ♦♦

m

♦B ^

♦d a

a

X > O 0

* •

Kd a♦ PI ♦

♦ • «

40d » a

a

a

♦X ♦ D • -

0 .......................N a a ' X ♦ B

d

a

: •

* ♦ . • * »

* ♦ B ♦ ......................................................... a

aa

r*d

aa

« XX

f ...........•* *► « /1 • * a 0O0

rtd

09

X rf**4d

X

XX

sCL

e

X ’T3

‘**0...........................................................................................................................................................................................

to » 30 « 90 00 70TIME(MINUTES)

too Ito IS

E-86

TRANSIENT NO. 41 [5A(LANL7)]

E -8 7

0.0

2.06.0

—I

I.8.0 L

_10

.0 12

.014

.0__

l__

16.0

I-18

.0

L_

*_

Mlrf

20.0

00 00

30.0

60

.090

.012

0.0

TEM

P.(D

EG.C

.)15

0.0

180.

0 21

3.0

240.

027

0.0

300.

0o o p o o

O Z

8 bP

I

p o

no oo

S o b s o s o

n COo

8 oC

J nID

o bO

S 1— b 0.0

20.0

14.0

18.0

18.0

2.04.

06.

08.0

10.0

12.0

PRES

S.(M

PR)

IPTS OCONEE CLAD 5A 1 0 /2 0 /3 3

WELD P (F /E )-UNADJUSTED-------------------------95%CX %ERR P(TNITIA) N»V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) %ERR

FO = 1 .0 9 0 D + 1 9

NTRIALS

1 2 .39D -02 2 .27D -03 9 .5 2 2 .91D -02 0 .0 9 0 9 .56D -04 100002 1.9UD-02 1 .26D -03 3 .7 5 1 . 94D-02 0 .0 9 0 5 .79D -09 200003 2. 39D-02 2 .27D -03 9 .5 2 2 . 93D-02 0 .0 1 0 2 . 39D-09 10000

VESSEL 1.77D-03 6.01

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 .3 1 2 .7 1 9 .0 2 5 .9 38. 1 50 .3

NUMBER 333 653 235 70 21 2 0PERCENT 2 5 .3 9 9 .7 1 7 .9 5 . 3 1 .6 0 . 2 0 .0

TIMES OF FAILURE(MINUTES)0 . 0 10 .0 2 0 .0 3 0 .0 9 0 .0 5 0 .0

NUMBER 0 0 0 0 0PERCENT 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0.

6 0 .0 7 0 . 0 8 0 .0 9 0 .0 1 0 0 .0 1 10 .0 120 .01 3 19 50 135 392 7581 0 . 2 1. 1 3 .8 1 0 .9 2 6 .2 5 8 .2

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 .9 2 7 .8 9 1 . 7 5 5 .6 6 9 .9 8 3 .3 9 7 .2 111.1

NUMBER 13 76 293 519 363 56 1 0 0 0 0 0PERCENT 1 .0 5 . 8 2 2 .3 39. 1 2 7 .6 9 . 3 0. 1 0 . 0 0 . 0 0 . 0 0 . 0 0 .0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9 0 . 0 13 .9 2 7 .8 9 1 .7 5 5 .6 6 9 .9 83. 3 9 7 .2 111. 1 125.0 138 .9

NUMBERPERCENT

00.0

00 . 0

53 8 .5

75 3 .8

17 . 7

00 . 0

00 . 0

00 . 0

00 . 0

00 . 0

00 . 0

00 . 0

E -8 9

IPTS OCONEE CLfiO 5fl 10/20/83

E -9 0

IPTS OCONEE CLAD 5fi 10/20/83

E -91

CRITlCflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLAD Sfl 10/20/83RTNDTO —6.7 DEOO XOU - 0.29 XNI - 0.55 FO - 1.09E19 LONCIT

r X □XX + D

X + D♦ ‘

X ♦ D ♦ -X 0

+

■

•

• ••

• s

♦^ * D ^ .X ^

+ D ♦

+ ^X + D « -X P +

♦p • •

•

: • . ■ ............•

...............

X + D «

- $ * B *

X ♦ □ «

x .

X aX

^ %X «

. . ...................... ................ ’‘ ’' ’‘ ? * ’‘’‘ ’‘ ?*???¥xx58!R bS !?S S S 8g8 l10 so eo 70

TIME(MINUTES)90 100 110 i:

E -9 2

TRANSIENT NO. H6 [6C(LANL12)]

E -9 3

IPTS OCONEE CLRD 6C 1 0 /2 0 /8 3

oC9 o5 8

UJ

D PRESS.fMPR)o TEMP.(PEG.C.)A HTC(N/Mxn2xK)

* <n tn u QCa .

0 .0 io .o x . o 30.0 40.0 50.0 60.0 70.0TIRE(MIN.)

60.0 90.0 100.0 110.0 120.0

E-94

IPTS OCONEE CLAD 6C 1 0 /2 0 /3 3

WELD P (F /E )-UNADJUSTED-------------------------9 5 tC I %ERR P(INITIA) N*V

1. FLAWS/M»»3

ADJUSTED-------P (F /E ) 'JERR

FO = 1 .0 9 O D + 1 9

NTRIALS

1 . «1D-05 8 .22D-06 1. 69D-05

7 .9SD -066 .09D -068 .61D -06

5 6 .5 87 9 .0 85 2 .3 8

5 .62D -03 0 .0 9 0 5 .69D -07 5000003 .81D -03 0 .0 9 0 3 .29D -07 5000006 .11D -03 0 .0 1 0 1 .69D-07 500000

VESSEL 1.06D-06 38 .8 3

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6. 3 1 2 .7 1 9 .0 2 5 .9 38. 1 5 0 .8

NUMBER 3113 9092 683 292 86 15 2PERCENT 2 3 .5 68. 3 5 . 2 2 . 2 0 . 6 0 . 1 0 .0

TIMES OF FAILURE(MINUTES)0 . 0 1 0 .0 2 0 .0 3 0 .0 9 0 .0 5 0 .0

NUMBER 0 0 0 0 0 0PERCENT 0 .0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0

6 0 .0 7 0 .0 8 0 .0 9 0 .0 1 0 0 .0 11 0 .0 1 2 0 .00 0 0 0 0 33

0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 100.0

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 9 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 ,9 27 . 8 9 1 .7 5 5 .6

NUMBER 1250 3605 5619 2882 392 66 8 0 0PERCENT 9. 1 2 6 .2 9 0 .8 2 0 .9 2 . 5 0 . 5 0 .1 0 . 0 0 . 0

6 9 .9 8 3 .3 9 7 .2 1 1 1.10

0.00

0 . 00

0.0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

33662 6 .3

38793 0 .3

0 .0 1 3 .9 2 7 .8 9 1 .7 5 5 .6 69.991 172 2516 1898 07 . 7 - 1 . 3 1 9 .6 1 9 .8 0 . 0

9 83.0

0 . 0

3 9 7 .2 111. 1 125 .0 138 .90

0 . 00

0 . 00

0 . 00

0 . 0

E -9 5

IPTS OCONEE CLflD 60 10/20/83

0.S0.S0.70.60 .5fl/W

0 .40 .30.20.1

IE -96

CRITlCflL CRflCK OEPTH CURVES FOR IPTS OCONEE CLflD 6C 10/20/83RTNDTO —6.7 DE8C XCU - 0.29 XNI - 0.55 FO - 1.09E19 LONGIT

220

2»

d ■

90 too 1100 20 3010 SO 7080 80 i:TIME(MINUTES)

E -97

IPTS OCOrCE CLflD 60 10/20/63

E -9 8

TRANSIENT NO. 57 (INEL7)

E -9 9

•b o xsn

T(M

5<

IPTS OCONEE CLflD INEL7 1 2 /2 2 /8 3

oCS o

0 8

p PRESS.(MPfl)o TEflP, (DCe.C,)A HTC(^/Mxx2mK)

100.0 110.0 120.090.070.0 80.0SO.O 80.030.0 40.0».010.00 .0

cQ..3C• <ntnLi

0.

TIMEtMIN.)

E -1 0 0

IPTS OCONEE CLAD INEL7 1 2 / 2 2 / 8 3

WELD P(F /E )-UNADJUSTED-------------------------9 5 t C I ■tERR P(INITIA) N»V

1. FLAWS/M»»3

ADJUSTED------p ( F / E ) i;err

FO = I . O 9OD+ I 9

NTRIALS

1 2 .26 D- 03 2. 15D-0U 9 . 50 2. 29D-03 0 . 0 4 0 9 . 06D-05 1 100002 9 . 81D-OH 9 . 6OD-O5 9 . 7 8 9 .81D- 04 0 . 0 4 0 3 .9 3D- 05 2400003 2 . I 7D-O3 2 .10D- 04 9.71 2. I 8D-O3 0 . 0 1 0 2 . 17D- 05 1 10000

VESSEL 1 . 5 1 0- 0 4 6 . 3 7

DEPTHS FOR INITIAL INITIATION (MM)3 . 2 6 . 3 1 2 . 7 1 9 . 0 2 5 . 4 38 . 1 5 0 . !

NUMBER 346 536 275 58 18 4 1PERCENT 2 7 . 9 4 3 . 3 2 2 . 2 4 . 7 1 . 5 0 . 3 0 . 1

TIMES OF FAILURE(MINUTES)0 . 0 1 0 . 0 2 0 . 0 3 0 . 0 4 0 . 0 5 0 . 0 60.

NUMBER 0 93 727 357 8 10PERCENT 0 . 0 7 . 6 59. 1 2 9 . 0 0 . 6 0 . 8

0 7 0 . 0 8 0 . 0 9 0 . 0 100 . 0 110 .0 120 . 0 11 7 6 8 3 1

0. 9 0 . 6 0 . 5 0 . 6 0 . 2 0 .1

INITIATION T-RTNDT(DEG.C)- 5 5 . 6 - 4 1 . 7 - 2 7 . 8 - 1 3 . 9 0 . 0 1 3 . 9 27. 8 4 1 . 7 5 5 . 6 69.

NUMBER 0 0 23 184 526 446 99 8 0PERCENT 0 . 0 0 . 0 1 . 8 14. 3 4 0 . 9 3 4 . 7 7 . 7 0 . 6 0 . 0

4 83. 3 9 7 . 2 111.10 0 0

0 . 0 0 . 0 0 . 0

ARREST T-RTNDT(DEG.C)- 2 7 . 8 - 1 3 . 9

NUMBERPERCENT

00 . 0

0 . 0 13 . 9 0 0 0

0 . 0 0 . 0 0 . 0

2 7 . 8 4 1 . 7 5 5 . 6 6 9 . 4 8 3 . 3 9 7 . 2 111. 1 125 .0 138 .90 0 0 2 1 34 0 0 0

0 . 0 0 . 0 0 . 0 3 8 . 2 6 1 . 8 0 . 0 0 . 0 0 . 0

E -1 0 1

IF*TS OCONEE CLflD I EL7 12/22/83

E - 1 0 2

IPTS OCONEE CLflD INEL7 1 2 /2 2 /8 3

E -1 0 3

CRITlCflL CRflCK DEPTH CURVES FOR IPTS OCONEE CLflD INEL7 1 2 /2 2 /8 3RTNDTO — 6 .7 DECC XCU - 0 .2 9 XNI - 0 .5 5 FO - 1 .09E 19 LONCIT

XX

+

c

o

++

X -fX ♦

sJt +

□

□

0a

D O

® C n c Q o Q Q Q Q D o p D D O D D O Q O D D D n n n D D n n O D D D D 1

so eo 70 TIMEtniNUTES)

E -1 0 4

APPENDIX F

ALTERNATIVE APPROACH TO SEQUENCE ASSIGNMENT

A review o f th e ass ignm ent o f r e p r e s e n t a t i v e f ra c tu re -m e c h a n ic s c a se s to e a c h s e q u e n c e , a s p re s e n te d in Table A.3 o f Appendix A, re v e a le d bo th c o n s e rv a t iv e and n o n -c o n s e rv a t iv e a ss ig n m e n ts . I t was th e o p in io n o f th e a n a l y s t s t h a t in g e n e ra l c o n s e rv a t iv e and sometimes o v e r ly c o n s e rv a t iv e ass ignm en ts were made. T h is was p a r t i c u l a r l y t r u e f o r th e ass ignm ent o f a f r a c t u r e m echanics case t o th e r e s i d u a l c a s e s . An a t te m p t was made to r e c o n s t r u c t th e t a b l e and th u s reduce th e le v e l o f co n se rv a t ism Invo lved in t h i s p o r t i o n o f th e Oconee a n a l y s i s . U n fo r tu n a te ly , th e r e was l i t t l e t h a t c o u ld be done w i t h o u t p e r f o r m i n g a d d i t i o n a l t h e r m a l - h y d r a u l i c a n d /o r f r a c tu r e - m e c h a n ic s c a l c u l a t i o n s . In a d d i t i o n th e r e s o l u t i o n o f th e few n o n -c o n se rv a t iv e a ss ignm en ts le d to a h ig h e r o v e r a l l v e s s e l f a i l u r e v a lu e . Thus in t r y i n g to reduce bo th th e c o n s e rv a t iv e and n o n -c o n s e rv a t iv e b ia s e s in t ro d u ced by th e ass ignm ent o f f ra c tu re -m e c h a n ic s c a s e s , we produced a s e t o f d a ta which was c l e a r l y b ia se d in th e c o n s e rv a t iv e d i r e c t i o n . This d a ta i s p re s e n te d h e re a s a s e p a r a t e appendix s in c e i t in c lu d e s th e e l im in a t io n o f some o f th e n o n -c o n s e rv a t iv e b ia s e s found in th e a n a l y s i s even though i t f a i l s to a d d re s s th e l a r g e r c a te g o ry o f c o n s e rv a t iv e b i a s e s .

F . l

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T) P(TWC)1 NORM RT 0 0 0 0 5.0E+00 NONE l.OE+00 5.0E+00 O.OE+00 O.OE+002 FW RT 0 1 0 0 1.6E-01 0VRFD3 l.OE+00 1.6E-01 l.OE-07 1 . 6E-083 FW RT 0 3 0 1 4 . 9E-04 PSBG2 9.9E-01 4.9E-04 l.OE-07 4.9E-114 FW RT 0 3 0 1 4.9E-04 PSBG4 l.OE-02 4.9E-06 1.3E-03 6.4E-095 FW RT 0 3 0 2 3.0E-05 PSBG2 9.9E-01 3.0E-05 l.OE-07 3.0E-126 FW RT 0 3 0 2 3.0E-05 PSBG4 l.OE-02 3.0E-07 1.3E-03 3.9E-107 FW RT 0 4 0 0 1.9E-03 NONE 9.9E-01 1.9E-03 0 .0 0 .08 FW RT 0 4 0 0 1.9E-03 0VRFD6 l.OE-02 1 . 9E-05 1.4E-06 2.7E-119 FW RT 0 4 0 0 1.9E-03 0VRFD7 3 . 6E-03 6.8E-06 l.OE-07 6.8E-13

10 FW RT 0 4 0 1 4.7E-05 NONE 9.9E-01 4.7E-05 0 ,0 0 .011 FW RT 0 4 0 1 4.7E-05 PSBG4 l.OE-02 4.7E-07 1.3E-03 6.1E-1012 FW RT 0 4 0 1 4.7E-05 PSBG2 3.6E-03 1.7E-07 l.OE-07 1.7E-1413 FW RT 0 4 0 2 1.3E-04 NONE 9.9E-01 1.3E-04 0 .0 0 .014 FW RT 0 4 0 2 1 . 3E-04 PSBG4 l.OE-02 1.3E-06 1.3E-03 1 . 7E-0915 FW RT 0 4 0 2 1.3E-04 PSBG2 3.6E-03 4.7E-07 l.OE-07 4.7E-1416 FW RT 0 2 0 0 5.8E-04 MIN 9.9E-01 5.7E-04 l.OE-07 5.7E-1117 FW RT 0 2 0 0 5.8E-04 INEL6 l.OE-02 5.8E-06 4.2E-07 2.4E-1218 FW RT 0 2 0 1 1.4E-05 PSBG2 9 . 9E-01 1.4E-05 1 . OE-07 1.4E-1219 FW RT 0 2 0 1 1.4E-05 INEL6 l.OE-02 1.4E-07 4.2E-07 5.9E-1420 FW RT 0 2 0 2 3.7E-05 PSBG2 9.9E-01 3 . 7E-05 l.OE-07 3.7E-1221 FW RT 0 2 0 2 3.7E-05 INEL6 l.OE-02 3.7E-07 4.2E-07 1.6E-1322 SL RT 1 0 0 0 6.9E-01 TBVG2 9.9E-01 6.8E-01 1 . OE-07 6 . 8E-0823 SL RT 1 0 0 0 6.9E-01 TBV61 l.OE-02 6.9E-03 4.0E-07 2 . 8E-0924 SL RT 1 0 0 1 1 . 7E-02 PSBG5 9.9E-01 1 . 7E-02 l.OE-07 1 . 7E-0925 SL RT 1 0 0 1 1.7E-02 TBVG6 l.OE-02 1 . 7E-04 1 . 7E-06 2.9E-1026 SL RT 1 0 0 2 4.5E-02 PSBG5 9.9E-01 4.5E-02 l.OE-07 4 . 5E-0927 SL RT 1 0 0 2 4.5E-02 TBVG6 l.OE-02 4.5E-04 1.7E-06 7.7E-1028 SL RT 1 0 1 0 9.0E-04 TBVG2 9.9E-01 8.9E-04 l.OE-07 8.9E-1129 SL RT 1 0 1 0 9.0E-04 TBVGl l.OE-02 9.0E-06 4.0E-07 3.6E-1230 SL RT 1 0 1 1 2.2E-05 PSBG5 9.9E-01 2.2E-05 l.OE-07 2.2E-1231 SL RT 1 0 1 1 2.2E-05 TBVG6 l.OE-02 2.2E-07 1.7E-06 3.7E-1332 SL RT 1 0 1 2 5.6E-05 PSBG5 9.9E-01 5 . 5E-05 1 . OE-07 5.5E-1233 SL RT 1 0 1 2 5.6E-05 TBVG6 l.OE-02 5.6E-07 1.7E-06 9.5E-1334 SS RT 1 3 0 1 2 . 8E-05 PSBG5 9.9E-01 2.8E-05 l.OE-07 2.8E-1235 SS RT 1 3 0 1 2.8E-05 TBVG6 1.0E=02 2.8E-07 1.7E-06 4.8E-1336 SS RT 1 3 0 2 7 . 7E-05 PSBG5 9.9E-01 7.6E-05 1 . OE-07 7.6E-1237 SS RT 1 3 0 2 7.7E-05 TBVG6 l.OE-02 7.7E-07 1.7E-06 1.3E-1238 SS RT 1 4 0 0 5.0E-03 TBVG2 9.9E-01 5 . OE-03 l.OE-07 5.0E-1039 SS RT 1 4 0 0 5.0E-03 TBVGl l.OE-02 5.0E-05 4.0E-07 2.0E-1140 SS RT 1 4 0 0 5 . OE-03 TBVGl 3.6E-03 1.8E-06 4.0E-07 7.2E-1341 SS RT 1 4 0 1 1.2E-04 PSBG5 9.9E-01 1.2E-04 l.OE-07 1.2E-1142 SS RT 1 4 0 1 1.2E-04 TBVG6 1 . OE-02 1 . 2E-06 1.7E-06 2.0E-1243 SS RT 1 4 0 1 1 . 2E-04 TBVG6 3.6E-03 4.3E-07 1 . 7E-06 7.3E-1344 SS RT 1 4 0 2 3.2E-04 PSBG5 9.9E-01 3.2E-04 l.OE-07 3,2E-1145 SS RT 1 4 0 2 3.2E-04 TBVG6 l.OE-02 3.2E-06 1.7E-06 5.4E-1246 SS RT 1 4 0 2 3 . 2E-04 TBVG6 3.6E-03 1 . 2E-06 1 . 7E-06 2.0E-1247 SS RT 1 4 1 0 4.4E-06 TBVG2 9.9E-01 4.4E-06 l.OE-07 4.4E-1348 SS RT 1 4 1 0 4.4E-06 TBVGl l.OE-02 4.4E-08 4.0E-07 1.8E-1449 SS RT 1 4 1 0 4.4E-06 TBVGl 3.6E-03 1.6E-08 4.0E-07 6.4E-1550 SL RT 1 1 0 0 2.2E-02 TBVG3 9.9E-01 2.2E-02 1 . OE-07 2 . 2E-0951 SL RT 1 1 0 0 2.2E-02 TBVG4 1.0E-02 2.2E-04 2.0E-03 4.4E-0752 SS RT 1 1 0 1 5.4E-04 TBVG6 9.9E-01 5.3E-04 1 . 7E-06 9.0E-1053 SS RT 1 1 0 1 5.4E-04 TBVG6 l.OE-02 5.4E-06 1.7E-06 9.2E-12

F . 2

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)54 SS RT 1 1 0 2 1.4E-03 TBVG6 9.9E-01 1.4E-03 1 . 7E-06 2.4E-0955 SS RT 1 1 0 2 1.4E-03 TBVG6 l.OE-02 1.4E-05 1.7E-06 2.4E-1156 SS RT 1 1 1 0 2.8E-05 TBVG3 9.9E-01 2.8E-05 l.OE-07 2.8E-1257 SS RT 1 1 1 0 2.8E-05 TBVG4 l.OE-02 2.8E-07 2.0E-03 5.6E-1058 SS RT 1 2 0 0 8.8E-05 TBVG3 9.9E-01 8.7E-05 l.OE-07 8.7E-1259 SS RT 1 2 0 0 8.8E-05 TBVG4 1 . OE-02 8.8E-07 2.0E-03 1.9E-0960 SS RT 1 2 0 1 2.2E-06 TBVG4 9.9E-01 2.2E-06 2.0E-03 4.4E-0961 SS RT 1 2 0 1 2.2E-06 TBVG4 l.OE-02 2.2E-08 2.0E-03 4.4E-1162 SS RT 1 2 0 2 5.0E-06 TBVG4 9.9E-01 5.0E-06 2.0E-03 l.OE-0863 SS RT 1 2 0 2 5.0E-06 TBVG4 l.OE-02 5.0E-08 2.0E-03 l.OE-1064 SL RT 2 0 0 0 8.2E-03 TBVG2 9.9E-01 8.1E-03 l.OE-07 8.1E-1065 SL RT 2 0 0 0 8 .2E-03 TBVGl l.OE-02 8.2E-05 4.0E-07 3.3E-1166 SL RT 2 0 0 1 2.0E-04 PSBG5 9.9E-01 2.0E-04 l.OE-07 2.0E-1167 SL RT 2 0 0 1 2.0E-04 TBVG6 l.OE-02 2.0E-06 1.7E-06 3.4E-1268 SL RT 2 0 0 2 5 . 3E-04 PSBG5 9.9E-01 5.2E-04 l.OE-07 5.2E-1169 SL RT 2 0 0 2 5.3E-04 TBVG6 1 . OE-02 5.3E-06 1 . 7E-06 9.0E-1270 SL RT 2 0 1 0 9 .2E-06 TBVG2 9.9E-01 9.1E-06 l.OE-07 9.1E-1371 SL RT 2 0 1 0 9.2E-06 TBVGl l.OE-02 9.2E-08 4.0E-07 3.7E-1472 SS RT 2 3 0 0 1.2E-05 TBVG2 9.9E-01 1.2E-05 l.OE-07 1.2E-1273 SS RT 2 3 0 0 1.2E-05 LANL7 l.OE-02 1.2E-07 1.8E-03 2.2E-1074 SS RT 2 4 0 0 5.5E-05 TBVG2 9.9E-01 5.4E-05 l.OE-07 5.4E-1275 SS RT 2 4 0 0 5 .5E-05 0VRFD6 l.OE-02 5.5E-07 1.4E-06 7.7E-1376 SS RT 2 4 0 0 5 .5E-05 0VRFD7 3.6E-03 2.0E-07 l.OE-07 2.0E-1477 SS RT 2 4 0 2 2.6E-06 TBVGIO 9.9E-01 2.6E-06 l.OE-05 2.6E-1178 SS RT 2 4 0 2 2.6E-06 TBVGIO l.OE-02 2.6E-08 l.OE-05 2.6E-1379 SS RT 2 4 0 2 2 .6E-06 TBVG6 3.6E-03 9.4E-08 1.7E-06 1.6E-1380 SS RT 2 1 0 0 2.6E-04 TBVG3 9.9E-01 2.6E-04 l.OE-07 2.6E-1181 SS RT 2 1 0 0 2.6E-04 TBVG4 l.OE-02 2.6E-06 2.0E-03 5.2E-0982 SS RT 2 1 0 1 5.8E-06 TBVG6 9.9E-01 5.7E-06 1.7E-06 9.7E-1283 SS RT 2 1 0 1 5.8E-06 TBVG6 l.OE-02 5.8E-08 1.7E-06 9.9E-1484 SS RT 2 1 0 2 1.3E-05 TBVG6 9.9E-01 1.3E-05 1.7E-06 2.2E-1185 SS RT 2 1 0 2 1.3E-05 TBVG6 l.OE-02 1.3E-07 1.7E-06 2.2E-1386 SL RT 3 0 0 0 7.6E-02 TBVG5 9.9E-01 7.5E-02 5.2E-06 3.9E-0787 SL RT 3 0 0 0 7.6E-02 TBVG5 l.OE-02 7.6E-04 5.2E-06 4.0E-0988 SL RT 3 0 0 1 1.9E-03 TBVGIO 9.9E-01 1.9E-03 l.OE-05 1.9E-0889 SL RT 3 0 0 1 1.9E-03 TBVGIO l.OE-02 1 . 9E-05 l.OE-05 1.9E-1090 SL RT 3 0 0 2 5.0E-03 TBVGIO 9.9E-01 5.0E-03 l.OE-05 5.0E-0891 SL RT 3 0 0 2 5.0E-03 TBVGIO l.OE-02 5.0E-05 l.OE-05 5.0E-1092 SL RT 3 0 1 0 9.9E-05 TBVG5 9.9E-01 9.8E-05 5.2E-06 5.1E-1093 SL RT 3 0 1 0 9 .9E-05 TBVG5 1 . OE-02 9.9E-07 5.2E-06 5.1E-1294 SL RT 3 0 1 1 2.4E-06 TBVGIO 9.9E-01 2 . 4E-06 l.OE-05 2.4E-1195 SL RT 3 0 1 1 2.4E-06 TBVGIO l.OE-02 2.4E-08 l.OE-05 2.4E-1396 SL RT 3 0 1 2 5.5E-06 TBVGIO 9.9E-01 5.4E-06 l.OE-05 5.4E-1197 SL RT 3 0 1 2 5 .5E-06 TBVGIO l.OE-02 5.5E-08 l.OE-05 5.5E-1398 SS RT 3 3 0 0 1.4E-04 TBVG5 9.9E-01 1.4E-04 5.2E-06 7.3E-1099 SS RT 3 3 0 0 1.4E-04 LANL7 l.OE-02 1.4E-06 1.8E-03 2.5E-09100 SS RT 3 3 0 1 3.1E-06 TBVGIO 9.9E-01 3.1E-06 l.OE-05 3 . lE-11101 SS RT 3 3 0 1 3 .1E-06 TBVGIO 1 . OE-02 3.1E-08 1 . OE-05 3.1E-13102 SS RT 3 3 0 2 7.2E-06 TBVGIO 9.9E-01 7.1E-06 l.OE-05 7 . lE-11103 SS RT 3 3 0 2 7.2E-06 TBVGIO l.O E-02 7.1E-08 l.OE-05 7.1E-13104 SS RT 3 4 0 0 5.5E-04 TBVG5 9.9E-01 5.4E-04 5.2E-06 2.8E-09105 SS RT 3 4 0 0 5 .5E-04 TBVG9 l.OE-02 5.5E-06 2.0E-03 l . l E - 0 8106 SS RT 3 4 0 0 5.5E-04 TBVG9 3.6E-03 2.0E-06 2.0E-03 4.0E-09

F . 3

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)107 SS RT 3 4 0 1 1.3E-05 TBVGIO 9.9E-01 1 . 3E-05 l.OE-05 1.3E-10108 SS RT 3 4 0 1 1.3E-05 TBVGIO l.O E-02 1 . 3E-07 1 . OE-05 1.3E-12109 SS RT 3 4 0 1 1.3E-05 TBVGIO 3.6E-03 4 .7E-08 1 . OE-05 4.7E -13110 SS RT 3 4 0 2 3 . 3E-05 TBVGIO 9 . 9E-01 3 . 3E-05 l.OE-05 3 .3E-10111 SS RT 3 4 0 2 3 .3E-05 TBVGIO l.OE-02 3 .3E-07 l.OE-05 3 .3E-12112 SS RT 3 4 0 2 3 .3E-05 TBVGIO 3.6E-03 1 . 2E-07 1 . OE-05 1.2E-12113 SS RT 3 1 0 0 2 .4E-03 TBVG9 9.9E-01 2.4E-03 2 . OE-03 4 .8E-06114 SS RT 3 1 0 0 2 .4E-03 TBVG9 1 . OE-02 2.4E-05 2.0E-03 4 . 8E-08115 SS RT 3 1 0 1 6 .0E-05 TBVGIO 9.9E-01 5.9E-05 l.OE-05 5.9E -10116 SS RT 3 1 0 1 6 .0E-05 TBVGIO l.O E-02 5.9E-07 1 . OE-05 5.9E-12117 SS RT 3 1 0 2 1.6E-04 TBVGIO 9.9E-01 1.6E-04 l.OE-05 1.6E-09118 SS RT 3 1 0 2 1 . 6E-04 TBVGIO l.O E-02 1.6E-06 1 . OE-05 1.6E-11119 SS RT 3 1 1 0 2 . 6E-06 TBVG9 9.9E-01 2 . 6E-06 2.0E-03 5 . 2E-09120 SS RT 3 1 1 0 2 . 6E-06 TBVG9 l.O E-02 2 . 6E-08 2.0E-03 5.2E-11121 SS RT 3 2 0 0 8.7E-06 TBVG9 9.9E-01 8 . 6E-06 2.0E-03 1.7E-08122 SS RT 3 2 0 0 8 .7E-06 TBVG9 l.O E-02 8.6E-08 2 . OE-03 1.7E-10123 SL RT 4 0 0 0 6 . 9E-04 TBVG5 9.9E-01 6.8E-04 5 . 2E-06 3.5E -09124 SL RT 4 0 0 0 6 .9E-04 TBVG5 l.OE-02 6.9E-06 5.2E-06 3.6E-11125 SL RT 4 0 0 1 1 . 5E-05 TBVGIO 9.9E-01 1.5E-05 1 . OE-05 1.5E-10126 SL RT 4 0 0 1 1 . 5E-05 TBVGIO l.O E-02 1.5E-07 l.OE-05 1.5E-12127 SL RT 4 0 0 2 4 .3E-05 TBVGIO 9.9E-01 4.3E -05 l.OE-05 4.3E-10128 SL RT 4 0 0 2 4 .3E-05 TBVGIO l.O E-02 4.3E -07 l.OE-05 4.3E-12129 SS RT 4 4 0 0 3 .1E-06 TBVG5 9.9E-01 3.1E-06 5.2E-06 1.6E-11130 SS RT 4 4 0 0 3 .1E-06 TBVG9 1 . OE-02 3.1E -08 2 . OE-03 6.2E-11131 SS RT 4 4 0 0 3 .1E-06 TBVG9 3.6E-03 l . l E - 0 8 2.0E-03 2.2E-11132 SS RT 4 1 0 0 1.6E-05 TBVG9 9.9E-01 1.6E-05 2 . OE-03 3.2E-08133 SS RT 4 1 0 0 1.6E-05 TBVG9 l.OE-02 1.6E-07 2.0E-03 3.2E -10134 SL RT 5 0 0 0 4.5E-04 TBVG5 9.9E-01 4 . 5E-04 5 . 2E-06 2.3E-09135 SL RT 5 0 0 0 4.5E-04 TBVG5 l.OE-02 4.5E-06 5.2E-06 2,3E-11136 SL RT 5 0 0 1 1 . lE -05 TBVGIO 9.9E-01 1 . lE -0 5 l.OE-05 l . l E - 1 0137 SL RT 5 0 0 1 l . l E - 0 5 TBVGIO l.OE-02 1 . lE -07 l.OE-05 l . l E - 1 2138 SL RT 5 0 0 2 2 .8E-05 TBVGIO 9.9E-01 2 . 8E-05 1 . 0E-05 2.8E-10139 SL RT 5 0 0 2 2.8E-05 TBVGIO l.OE-02 2 .8E-07 l.OE-05 2.8E-12140 SS RT 5 4 0 0 2.2E-06 TBVG5 9.9E-01 2 .2E-06 5.2E-06 l . l E - 1 1141 SS RT 5 4 0 0 2.2E-06 TBVG9 l.O E-02 2 .2E-08 2.0E-03 4.4E-11142 SS RT 5 4 0 0 2 . 2E-06 TBVG9 3.6E -03 7 .9E-09 2 . OE-03 1.6E-11143 SS RT 5 1 0 0 1.4E-05 TBVG9 9.9E-01 1.4E-05 2 . OE-03 2 .8E-08144 SS RT 5 1 0 0 1.4E-05 TBVG9 l.O E-02 1.4E-07 2 . OE-03 2 .8E-10145 SL RT 6 0 0 0 5 .0E-04 MSLBl 9.9E-01 5.0E-04 6.2E-04 3 .1E-07146 SL RT 6 0 0 0 5 .0E-04 TBVG9 1 . OE-02 5 .0E-06 2.0E-03 l.O E-08147 SL RT 6 0 0 1 1 . 2E-05 MSLB7 9.9E-01 1 . 2E-05 6.2E-04 7 .4E-09148 SL RT 6 0 0 1 1 . 2E-05 TBVG9 l.O E-02 1 . 2E-07 2.0E-03 2 .4E-10149 SL RT 6 0 0 2 3 .1E-05 MSLB7 9.9E-01 3 .1E-05 6.2E-04 1 . 9E-08150 SL RT 6 0 0 2 3 .1E-05 TBVG9 l.O E-02 3 .1E-07 2.0E-03 6 .2E-10151 SS RT 6 4 0 0 2.5E-06 MSLBl 9.9E-01 2 . 5E-06 6.2E-04 1.6E-09152 SS RT 6 4 0 0 2 . 5E-06 TBVG9 l.O E-02 2.5E-08 2.0E-03 5.0E-11153 SS RT 6 4 0 0 2.5E-06 TBVG9 3.6E -03 9 .0E-09 2.0E-03 1.8E-11154 SS RT 6 1 0 0 1.6E-05 MSLB7 9.9E-01 1 . 6E-05 6.2E-04 9 .9E-09155 SS RT 6 1 0 0 1.6E-05 TBVG9 l.OE-02 1.6E-07 2.0E-03 3 .2E-10156 RES RT 1 . 9E-04 LANLIO 1 . OE+00 1 . 9E-04 5.4E-03 1 . OE-06157 FW EMFW 0 1 0 0 8 .4E-02 0VRFD3 l.OE+00 8 .4E-02 l.OE-07 8 .4E-09158 FW EMFW 0 3 0 0 1.4E-04 0VRFD6 9.9E-01 1.4E-04 1.4E-06 2 .0E-10159 FW EMFW 0 3 0 0 1.4E-04 0VRFD6 l.O E-02 1.4E-06 1.4E-06 2.0E-12

F . 4

■ REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(FIT) P(TWC)160 FW EMFW 0 3 0 1 2.9E-06 PSBG4 9.9E-01 2.9E-06 1.3E-03 3.8E-09161 FW EMFW 0 3 0 1 2.9E-06 PSBG4 l.OE-02 2.9E-08 1 . 3E-03 3.8E-11162 FW EMFW 0 3 0 2 6.8E-06 PSBG4 9.9E-01 6.7E-06 1.3E-03 8.7E-09163 FW EMFW 0 3 0 2 6.8E-06 PSBG4 l.OE-02 6.8E-08 1.3E-03 8.8E-11164 FW EMFW 0 4 0 0 5.5E-04 0VRFD6 9.9E-01 5.5E-04 1.4E-06 7.7E-10165 FW EMFW 0 4 0 0 5.5E-04 0VRFD6 l.OE-02 5.5E-06 1.4E-06 7.7E-12166 FW EMFW 0 4 0 0 5.5E-04 0VRFD7 3.6E-03 2.0E-06 l.OE-07 2.0E-13167 FW EMFW 0 4 0 1 1.3E-05 PSBG3 9.9E-01 1 . 3E-05 l.OE-07 1.3E-12168 FW EMFW 0 4 0 1 1.3E-05 PSBG4 l.OE-02 1.3E-07 1.3E-03 1.7E-10169 FW EMFW 0 4 0 1 1.3E-05 PSBG2 3.6E-03 4.7E-08 l.OE-07 4.7E-15170 FW EMFW 0 4 0 2 3.3E-05 PSBG3 9.9E-01 3.3E-05 l.OE-07 3.3E-12171 FW EMFW 0 4 0 2 3.3E-05 PSBG4 l.OE-02 3.3E-07 1.3E-03 4.3E-10172 FW EMFW 0 4 0 2 3.3E-05 PSBG2 3.6E-03 1.2E-07 l.OE-07 1.2E-14173 FW EMFW 0 2 0 0 3.1E-04 0VRFD5 9.9E-01 3.1E-04 l.OE-07 3,1E-11174 FW EMFW 0 2 0 0 3.1E-04 0VRFD5 l.OE-02 3.1E-06 l.OE-07 3.1E-12175 FW EMFW 0 2 0 1 7.7E-06 PSBG2 9.9E-01 7.6E-06 l.OE-07 7.6E-13176 FW EMFW 0 2 0 1 7.7E-06 PSBG2 l.OE-02 7.7E-08 l.OE-07 7.7E-15177 FW EMFW 0 2 0 2 2 . OE-05 PSBG2 9.9E-01 2.0E-05 l.OE-07 2.0E-12178 FW EMFW 0 2 0 2 2.0E-05 PSBG2 l.OE-02 2.0E-07 l.OE-07 2.0E-14179 SS EMFW 1 1 0 0 1.2E-02 TBVG3 9.9E-01 1.2E-02 l.OE-07 1.2E-09180 SS EMFW 1 1 0 0 1.2E-02 TBVG4 l.OE-02 1.2E-04 2.0E-03 2.4E-07181 SS EMFW 1 1 0 1 2.9E-04 TBVG6 9.9E-01 2.9E-04 1 . 7E-06 4.9E-10182 SS EMFW 1 1 0 1 2.9E-04 TBVG6 l.OE-02 2.9E-06 1.7E-06 4.9E-12183 SS EMFW 1 1 0 2 7.7E-04 TBVG6 9.9E-01 7 . 6E-04 1.7E-06 1.3E-09184 SS EMFW 1 1 0 2 7.7E-04 TBVG6 l.OE-02 7.7E-06 1 . 7E-06 1.3E-11185 SS EMFW 1 1 1 0 1.2E-05 TBVG3 9.9E-01 1 . 2E-05 l.OE-07 1.2E-12186 SS EMFW 1 1 1 0 1.2E-05 TBVG4 l.OE-02 1.2E-07 2.0E-03 2.4E-10187 SS EMFW 1 3 0 0 1.6E-05 TBVG2 9.9E-01 1.6E-05 l.OE-07 1.6E-12188 SS EMFW 1 3 0 0 1.6E-05 LANL7 l.OE-02 1.6E-07 1.8E-03 2.9E-10189 SS EMFW 1 4 0 0 8.0E-05 TBVG2 9.9E-01 7.9E-05 l.OE-07 7.9E-12190 SS EMFW 1 4 0 0 8.0E-05 TBVGl l.OE-02 8.0E-07 4.0E-07 3.2E-13191 SS EMFW 1 4 0 0 8.0E-05 TBVGl 3.6E-03 2 . 9E-07 4.0E-07 1.2E-13192 SS EMFW 1 4 0 2 3.5E-06 TBVGIO 9.9E-01 3.5E-06 l.OE-05 3.5E-11193 SS EMFW 1 4 0 2 3.5E-06 TBVGIO l.OE-02 3 .5E-08 1 . OE-05 3.5E-13194 SS EMFW 1 4 0 2 3.5E-06 TBVG4 3.6E-03 1.3E-08 2.0E-03 2.6E-11195 SS EMFW 1 2 0 0 4.7E-05 TBVG4 9.9E-01 4.7E-05 2.0E-03 9.4E-08196 SS EMFW 1 2 0 0 4.7E-05 TBVG4 l.OE-02 4.7E-07 2.0E-03 9.4E-10197 SS EMFW 1 2 0 2 2.7E-06 TBVG6 9.9E-01 2.7E-06 1.7E-06 4.6E-12198 SS EMFW 1 2 0 2 2.7E-06 TBVG6 l.OE-02 2 . 7E-08 1.7E-06 4.6E-14199 SS EMFW 2 1 0 0 1.4E-04 TBVG3 9.9E-01 1.4E-04 1 . OE-07 1.4E-11200 SS EMFW 2 1 0 0 1.4E-04 TBVG4 l.OE-02 1.4E-06 2.0E-03 2.8E-09201 SS EMFW 2 1 0 1 3.1E-06 TBVG6 9.9E-01 3.1E-06 1 . 7E-06 5.3E-12202 SS EMFW 2 1 0 1 3.1E-06 TBVG6 l.OE-02 3.1E-08 1.7E-06 5.3E-14203 SS EMFW 2 1 0 2 7.2E-06 TBVG6 9.9E-01 7.1E-06 1 . 7E-06 1.2E-11204 SS EMFW 2 1 0 2 7.2E-06 TBVG6 l.OE-02 7.2E-08 1.7E-06 1.2E-13205 SS EMFW 3 1 0 0 1.3E-03 TBVG5 9.9E-01 1 . 3E-03 5.2E-06 6.7E-09206 SS EFFW 3 1 0 0 1.3E-03 TBVG9 l.OE-02 1.3E-05 2.0E-03 2.6E-08207 SS EMFW 3 1 0 1 3.2E-05 TBVGIO 9.9E-01 3.2E-05 l.OE-05 3.2E-10208 SS EMFW 3 1 0 1 3.2E-05 TBVGIO l.OE-02 3 .2E-07 l.OE-05 3.2E-12209 SS EMFW 3 1 0 2 8.4E-05 TBVGIO 9.9E-01 8 .3E-05 l.OE-05 8.3E-10210 SS EMFW 3 1 0 2 8.4E-05 TBVGIO l.OE-02 8.4E-07 1 . OE-05 8.4E-12211 SS EMFW 3 1 1 0 1.4E-06 TBVG5 9.9E-01 1.4E-06 5.2E-06 7.3E-12212 SS EMFW 3 1 1 0 1.4E-06 TBVG9 l.OE-02 1.4E-08 2.0E-03 2.8E-11

F.5

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC) 1213 SS EMFW 3 3 0 0 1.8E-06 TBVG5 9.9E-01 1.8E-06 5.2E-06 9.4E-12*214 SS EMFW 3 3 0 0 1.8E-06 LANL7 l.OE-02 1. 8E-08 1.8E-03 3.2E-11215 SS EMFW 3 4 0 0 7.5E-06 TBVG5 9.9E-01 7.4E-06 5 . 2E-06 3.8E-11216 SS EMFW 3 4 0 0 7.5E-06 TBVG5 l.OE-02 7.5E-08 5 . 2E-06 3.9E-13217 SS EMFW 3 4 0 0 7.5E-06 TBVG9 3.6E-03 2.7E-08 2.0E-03 5.4E-11218 SS EMFW 3 2 0 0 4.7E-06 TBVG9 9.9E-01 4.7E-06 2.0E-03 9.4E-09219 SS EMFW 3 2 0 0 4.7E-06 TBVG9 l.OE-02 4.7E-08 2.0E-03 9.4E-11220 SS EMFW 4 1 0 0 8.6E-06 TBVG5 9.9E-01 8.5E-06 5.2E-06 4.4E-11221 SS EMFW 4 1 0 0 8.6E-06 TBVG9 l.OE-02 8.6E-08 2.0E-03 1.7E-10222 SS EMFW 5 1 0 0 6.3E-06 TBVG5 9.9E-01 6.2E-06 5.2E-06 3.2E-11223 SS EMFW 5 1 0 0 6.3E-06 TBVG9 l.OE-02 6.3E-08 2.0E-03 1.3E-10224 SS EMFW 6 1 0 0 7.0E-06 MSLB7 9.9E-01 6.9E-06 6.2E-04 4.3E-09225 SS EMFW 6 1 0 0 7.0E-06 TBVG9 l.OE-02 7.0E-08 2.0E-03 1.4E-10226 RES EMFW 7 . 2E-05 LANL7 l.OE+00 7.2E-05 1.8E-03 1.3E-07227 SL LSLB 1 0 0 0 9.6E-04 MSLBl 9.9E-01 9.5E-04 6.2E-04 5.9E-07228 SL LSLB 1 0 0 0 9.6E-04 MSLB4 l.OE-02 9.6E-06 3.0E-03 2.9E-08229 SL LSLB 1 1 0 0 3.0E-05 MSLB3 9.9E-01 3.0E-05 4.0E-04 1 . 2E-08230 SL LSLB 1 1 0 0 3.0E-05 TBVG9 l.OE-02 3.0E-07 2.0E-03 6.0E-10231 SL LSLB 3 0 0 0 5.5E-06 MSLBl 9.9E-01 5.4E-06 6.2E-04 3.3E-09232 SL LSLB 3 0 0 0 5.5E-06 TBVG9 l.OE-02 5.5E-08 2.0E-03 l . lE - 1 0233 RES LSLB 5.3E-06 MSLB4 l.OE+00 5.3E-06 3.0E-03 1.6E-08234 SL SSLB 1 0 0 0 9.0E-03 TBVG2 9.9E-01 8 . 9E-03 1 . OE-07 8.9E-10235 SL SSLB 1 0 0 0 9.0E-03 TBVGl l.OE-02 9.0E-05 4.0E-07 3.6E-11236 SL SSLB 1 1 0 0 2 . 8E-04 TBVG3 9.9E-01 2.8E-04 l.OE-07 2.8E-11237 SL SSLB 1 1 0 0 2.8E-04 TBVG4 l.OE-02 2 . 8E-06 2.0E-03 5.6E-09238 SS SSLB 1 4 0 0 2.4E-06 TBVG2 9.9E-01 2.4E-06 l.OE-07 2.4E-13239 SS SSLB 1 4 0 0 2.4E-06 TBVGl l.OE-02 2.4E-08 1.4E-06 3.4E-14240 SS SSLB 1 4 0 0 2.4E-06 TBVGl 3.6E-03 8.6E-09 4.0E-07 3.5E-15241 SL SSLB 3 0 0 0 6.3E-04 TBVG5 9.9E-01 6.2E-04 5.2E-06 3.2E-09242 SL SSLB 3 0 0 0 6.3E-04 TBVG5 l.OE-02 6.3E-06 5.2E-06 3.3E-11243 SL SSLB 3 0 0 1 1.5E-05 TBVGIO 9.9E-01 1.5E-05 l.OE-05 1.5E-10244 SL SSLB 3 0 0 1 1.5E-05 TBVGIO l.OE-02 1.5E-07 l.OE-05 1.5E-12245 SL SSLB 3 0 0 2 4.0E-05 TBVGIO 9.9E-01 4.0E-05 l.OE-05 4.0E-10246 SL SSLB 3 0 0 2 4.0E-05 TBVGIO l.OE-02 4.0E-07 l.OE-05 4.0E-12247 SL SSLB 3 1 0 0 2.0E-05 TBVG9 9.9E-01 2.0E-05 2.0E-03 4.0E-08248 SL SSLB 3 1 0 0 2.0E-05 TBVG9 l.OE-02 2.0E-07 2.0E-03 4.0E-10249 SL SSLB 3 1 0 2 l.OE-06 TBVGIO 9.9E-01 l.OE-06 l.OE-05 l.OE-11250 SL SSLB 3 1 0 2 l.OE-06 TBVGIO l.OE-02 l.OE-08 l.OE-05 l.OE-13251 SL SSLB 4 0 0 0 6.5E-06 TBVG2 9.9E-01 6.4E-06 l.OE-07 6.4E-13252 SL SSLB 4 0 0 0 6.5E-06 TBVGl l.OE-02 6.5E-08 4.0E-07 2.6E-14253 RES SSLB 1.4E-05 TBVG9 1 . OE+00 1.4E-05 2.0E-03 2.8E-08254 NORM LOMFW 0 0 0 0 5.5E-01 NONE 1 . OE+00 5.5E-01 O.OE+00 O.OE+00255 LOCA LOMFW 0 0 0 1 1.4E-02 PSBG3 l.OE+00 1.4E-02 l.OE-07 1.4E-09256 LOCA LOMFW 0 0 0 2 3.6E-02 PSBG3 l.OE+00 3.6E-02 l.OE-07 3 . 6E-09257 FW LOMFW 0 3 0 0 2.0E-03 INEL3 9.9E-01 2.0E-03 l.OE-07 2.0E-10258 FW LOMFW 0 3 0 0 2.0E-03 INEL3 l.OE-02 2.0E-05 l.OE-07 2.0E-12259 FW LOMFW 0 3 0 1 5 . lE-05 PSBG5 9.9E-01 5.1E-05 1.0E-07 5.1E-12260 FW LOMFW 0 3 0 1 5.1E-05 PSBG4 l.OE-02 5.1E-07 1.3E-03 6.6E-10261 FW LOMFW 0 3 0 2 1.3E-04 PSBG5 9.9E-01 1.3E-04 l.OE-07 1.3E-11262 FW LOMFW 0 3 0 2 1.3E-04 PSBG4 l.OE-02 1.3E-06 1 . 3E-03 1.7E-09263 FW LOMFW 0 4 0 0 3.9E-03 NONE 9.9E-01 3.9E-03 O.OE+00 O.OE+00264 FW LOMFW 0 4 0 0 3 . 9E-03 0VRFD6 1 . OE-02 3.9E-05 1.4E-06 5.5E-11265 FW LOMFW 0 4 0 0 3.9E-03 0VRFD7 3.6E-03 1.4E-05 l.OE-07 1.4E-12

F . 6

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)266 FW LOMFW 0 4 0 1 9.5E-05 PSBG3 9.9E-01 9.4E-05 l.OE-07 9.4E-12267 FW LOMFW 0 4 0 1 9.5E-05 PSBG4 l.OE-02 9.5E-07 1.3E-03 1.2E-09268 FW LOMFW 0 4 0 1 9.5E-05 PSBG2 3.6E-03 3.4E-07 l.OE-07 3.4E-14269 FW LOMFW 0 4 0 2 2.5E-04 PSBG3 9.9E-01 2.5E-04 l.OE-07 2.5E-11270 FW LOMFW 0 4 0 2 2.5E-04 PSBG4 1 . OE-02 2.5E-06 1.3E-03 3.3E-09271 FW LOMFW 0 4 0 2 2.5E-04 PSBG2 3.6E-03 9.0E-07 l.OE-07 9.0E-14272 SL LOMFW 1 0 0 0 8.4E-02 TBVG2 9.9E-01 8.3E-02 l.OE-07 8.3E-09273 SL LOMFW 1 0 0 0 8.4E-02 TBVGl l.OE-02 8.4E-04 4.0E-07 3.4E-1G274 SL LOMFW 1 0 0 1 2.1E-03 TBVG6 9.9E-01 2 . lE-03 1.7E-06 3.6E-09275 SL LOMFW 1 0 0 1 2.1E-03 TBVG6 l.OE-02 2.1E-05 1.7E-06 3.6E-11276 SL LOMFW 1 0 0 2 5.5E-03 TBVG6 9.9E-01 5.5E-03 1.7E-06 9.4E-09277 SL LOMFW 1 0 0 2 5.5E-03 TBVG6 l.OE-02 5.5E-05 1.7E-06 9.4E-11278 SL LOMFW 1 0 1 0 l . lE - 0 4 TBVG2 9.9E-01 l . lE - 0 4 l.OE-07 l . lE - 1 1279 SL LOMFW 1 0 1 0 1 . lE-04 TBVGl 1 .OE-02 l . l E - 0 6 4.0E-07 4.4E-13280 SL LOMFW 1 0 1 1 2.7E-06 TBVG6 9.9E-01 2 . 7E-06 1.7E-06 4.6E-12281 SL LOMFW 1 0 1 1 2 . 7E-06 TBVG6 l.OE-02 2.7E-08 1 . 7E-06 4.6E-14282 SL LOMFW 1 0 1 2 6.2E-06 TBVG6 9.9E-01 6.1E-06 1.7E-06 l.OE-11283 SL LOMFW 1 0 1 2 6.2E-06 TBVG6 l.OE-02 6.2E-08 1.7E-06 l . l E - 1 3284 SS LOMFW 1 3 0 0 3.1E-04 TBVG2 9.9E-01 3.1E-04 l.OE-07 3.1E-11285 SS LOMFW 1 3 0 0 3.1E-04 LANL7 l.OE-02 3 .1E-06 1.8E-03 5.6E-09286 SS LOMFW 1 3 0 1 7.0E-06 PSBG5 9.9E-01 6.9E-06 l.OE-07 6.9E-13287 SS LOMFW 1 3 0 1 7.0E-06 TBVG6 l.OE-02 7.0E-08 1.7E-06 1.2E-13288 SS LOMFW 1 3 0 2 1.6E-05 PSBG5 9.9E-01 1.6E-05 l.OE-07 1.6E-12289 SS LOMFW 1 3 0 2 1.6E-05 TBVG6 l.OE-02 1.6E-07 1.7E-06 2.7E-13290 SS LOMFW 1 4 0 0 5.9E-04 TBVG2 9.9E-01 5.8E-04 l.OE-07 5.8E-11291 SS LOMFW 1 4 0 0 5.9E-04 TBVGl l.OE-02 5.9E-06 4.0E-07 2.4E-12292 SS LOMFW 1 4 0 0 5.9E-04 TBVGl 3.6E-03 2.1E-06 4.0E-07 8.5E-13293 SS LOMFW 1 4 0 1 1.5E-05 PSBG5 9.9E-01 1 . 5E-05 l.OE-07 1.5E-12294 SS LOMFW 1 4 0 1 1.5E-05 TBVG6 l.OE-02 1.5E-07 1.7E-06 2.6E-13295 SS LOMFW 1 4 0 1 1.5E-05 TBVG6 3.6E-03 5.4E-08 1.7E-06 9.2E-14296 SS LOMFW 1 4 0 2 3.7E-05 PSBG5 9.9E-01 3.7E-05 l.OE-07 3.7E-12297 SS LOMFW 1 4 0 2 3.7E-05 TBVG6 l.OE-02 3.7E-07 1 . 7E-06 6.3E-13298 SS LOMFW 1 4 0 2 3.7E-05 TBVG6 3.6E-03 1.3E-07 1.7E-06 2.2E-13299 SL LOMFW 2 0 0 0 9.8E-04 TBVG2 9.9E-01 9.7E-04 l.OE-07 9.7E-11300 SL LOMFW 2 0 0 0 9.8E-04 TBVGl l.OE-02 9.8E-06 4.0E-07 3.9E-12301 SL LOMFW 2 0 0 1 2.4E-05 TBVG6 9.9E-01 2.4E-05 1.7E-06 4.1E-11302 SL LOMFW 2 0 0 1 2.4E-05 TBVG6 l.OE-02 2.4E-07 1.7E-06 4.1E-13303 SL LOMFW 2 0 0 2 6.3E-05 TBVG6 9.9E-01 6.2E-05 1.7E-06 l . l E - 1 0304 SL LOMFW 2 0 0 2 6.3E-05 TBVG6 l.OE-02 6.3E-07 1.7E-06 l . lE - 1 2305 SS LOMFW 2 3 0 0 3.0E-06 TBVG2 9.9E-01 3.0E-06 l.OE-07 3.0E-13306 SS LOMFW 2 3 0 0 3 .0E-06 LANL7 l.OE-02 3.0E-08 1.8E-03 5.4E-11307 SS LOMFW 2 4 0 0 5 .0E-06 TBVG2 9.9E-01 5.0E-06 l.OE-07 5.0E-13308 SS LOMFW 2 4 0 0 5 .0E-06 TBVGl l.OE-02 5.0E-08 4.0E-07 2.0E-14309 SS LOMFW 2 4 0 0 5 .0E-06 TBVGl 3 .6E-03 1.8E-08 4.0E-07 7.2E-15310 SL LOMFW 3 0 0 0 9 .2E-03 TBVG5 9.9E-01 9.1E-03 5.2E-06 4.7E-08311 SL LOMFW 3 0 0 0 9.2E-03 TBVG5 l.OE-02 9.2E-05 5.2E-06 4.8E-08312 SL LOMFW 3 0 0 1 2.3E-04 TBVGIO 9.9E-01 2.3E-04 l.OE-05 2.3E-09313 SL LOMFW 3 0 0 1 2.3E-04 TBVGIO l.O S-02 2.3E-06 l.OE-05 2.3E-11314 SL LOMFW 3 0 0 2 6.0E-04 TBVGIO 9.9E-01 5.9E-04 l.OE-05 5.9E-09315 SL LOMFW 3 0 0 2 6 .0E-04 TBVGIO l.OE-02 6.0E-06 l.OE-05 6.0E-11316 SL LOMFW 3 0 1 0 1.2E-05 TBVG5 9.9E-01 1.2E-05 5.2E-06 6.2E-11317 SL LOMFW 3 0 1 0 1.2E-05 TBVG5 l.OE-02 1.2E-07 5.2E-06 6.2E-13318 SS LOMFW 3 3 0 0 3 .4E-05 TBVG5 9.9E-01 3.4E-05 5.2E-06 1.8E-10

F. 7

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T) P(TWC)|319 SS LOMFW 3 3 0 0 3.4E-05 LANL7 l.OE-02 3.4R-07 1.8E-03 6.1E-1(P320 SS LOMFW 3 3 0 2 1 . 8E-06 TBVGIO 9.9E-01 1.8E-06 l.OE-05 1.8E-11321 SS LOMFW 3 3 0 2 1 . 8E-06 TBVGIO l.OE-02 1.8E-08 l.OE-05 1.8E-13322 SS LOMFW 3 4 0 0 6 . 5E-05 TBVG5 9.9E-01 6.4E-05 5.2E-06 3.3E -10323 SS LOMFW 3 4 0 0 6 .5E-05 TBVG9 l.OE-02 6.5E -07 2.0E-03 1.3E-09324 SS LOMFW 3 4 0 0 6 .5E-05 TBVG9 3.6E-03 2.3E-07 2 . OE-03 4.6E -10325 SS LOMFW 3 4 0 1 1.3E-06 TBVGIO 9.9E-01 1.3E-06 l.OE-05 1.3E-11326 SS LOMFW 3 4 0 1 1 . 3E-06 TBVGIO l.OE-02 1 . 3E-08 l.OE-05 1.3E-13327 SS LOMFW 3 4 0 1 1.3E-06 TBVGIO 3.6E-03 4 .7E-09 l.OE-05 4 .7E-14328 SS LOMFW 3 4 0 2 3.0E-06 TBVGIO 9.9E-01 3 .0E-06 l.OE-05 3.0E-11329 SS LOMFW 3 4 0 2 3.0E-06 TBVGIO l.OE-02 3 .0E-08 1 . OE-05 3 .0E-13330 SS LOMFW 3 4 0 2 3.0E-06 TBVGIO 3.6E-03 l . l E - 0 8 l.O E-05 l . l E - 1 3331 SL LOMFW 4 0 0 0 8.3E-05 TBVG5 9.9E-01 8 .2E-05 5.2E-06 4 .3E-10332 SL LOMFW 4 0 0 0 8 . 3E-05 TBVG5 1 . OE-02 8 .3E-07 5 . 2E-06 4 .3E-12333 SL LOMFW 4 0 0 2 4 .3E-06 TBVGIO 9.9E-01 4 . 3E-06 l.OE-05 4.3E-11334 SL LOMFW 4 0 0 2 4.3E -06 TBVGIO l.OE-02 4 .3E-08 1 . OE-05 4.3E -13335 SL LOMFW 5 0 0 0 5 .4E-05 TBVG5 9.9E-01 5 .3E-05 5.2E-06 2 .8E-10336 SL LOMFW 5 0 0 0 5.4E -05 TBVG6 l.O E-02 5 .4E-07 5.2E-06 2 .8E-12337 SL LOMFW 5 0 0 1 1.3E-06 TBVGIO 9.9E-01 1.3E-06 l.OE-05 1.3E-11338 SL LOMFW 5 0 0 1 1.3E-06 TBVGIO l.OE-02 1.3E-08 l.OE-05 1.3E-13339 SL LOMFW 5 0 0 2 3.1E-06 TBVGIO 9.9E-01 3 .1E-06 l.OE-05 3.1E-11340 SL LOMFW 5 0 0 2 3 .1E-06 TBVGIO l.OE-02 3 .1E-08 1 . OE-05 3 .1E-13341 SL LOMFW 6 0 0 0 6 .1E-05 MSLBl 9.9E-01 6 .0E-05 6.2E-04 3 .7E-08342 SL LOMFW 6 0 0 0 6 .1E-05 MSLBl 9.9E-01 6.0E-05 6 . 2E-04 3 . 7E-08343 SL LOMFW 6 0 0 0 6 .1E-05 TBVG9 l.OE-02 6.1E-07 2.0E-03 1.2E-09344 SL LOMFW 6 0 0 1 1 . 5E-06 MSLB7 9.9E-01 1.5E-06 6 . 2E-04 9 .3E-10345 SL LOMFW 6 0 0 1 1.5E-06 TBVG9 l.OE-02 1.5E-08 2.0E-03 3.0E-11346 SL LOMFW 6 0 0 2 3 .5E-06 MSLB7 9.9E-01 3 .5E-06 6.2E-04 2 . 2E-09347 SL LOMFW 6 0 0 2 3 .5E-06 TBVG9 l.OE-02 3.5E-08 2.0E-03 7.0E-11348 RES LOMFW 5.9E-05 TBVG9 l.OE+00 5.9E-05 2.0E-03 1.2E-07349 LOCA SBLl 0 0 0 0 7 .6E-02 PSBGl l.OE+00 7.6E-02 l.OE-07 7.6E-09350 LOCA SBLl 0 0 0 1 1 . 9E-03 PSBGl l.OE+00 1 . 9E-03 1 . OE-07 1.9E-10351 LOCA SBLl 0 0 0 2 5 .0E-03 PSBGl l.OE+00 5 .0E-03 l.OE-07 5 .0E-10352 LOCA SBLl 0 0 1 0 9 .9E-05 PSBGl l.OE+00 9 .9E-05 l.OE-07 9.9E-12353 LOCA SBLl 0 0 1 1 2 .4E-06 PSBGl l.OE+00 2.4E-06 l.OE-07 2.4E-13354 LOCA SBLl 0 0 1 2 5.5E-06 PSBGl l.OE+00 5 .5E-06 l.OE-07 5 .5E-13355 LOCA SBLl 0 1 0 0 2.4E-03 PSBG2 1 . OE+00 2.4E-03 l.OE-07 2.4E-10356 LOCA SBLl 0 1 0 1 5 .9E-05 PSBG2 1 . OE+00 5.9E-05 l.OE-07 5.9E-12357 LOCA SBLl 0 1 0 2 1.6E-04 PSBG2 l.OE+00 1.6E-04 l.OE-07 1.6E-11358 LOCA SBLl 0 1 1 0 2 .5E-06 PSBG2 1 . OE+00 2 . 5E-06 1 . OE-07 2 .5E-13359 LOCA SBLl 0 3 0 0 6 .6E-06 PSBG2 9.9E-01 6 .5E-06 l.OE-07 6 .5E-13360 LOCA SBLl 0 3 0 0 6 . 6E-06 PSBG4 l.OE-02 6 .6E-08 1 . 3E-03 8.6E-11361 LOCA SBLl 0 4 0 0 3 .1E-05 NONE 9.9E-01 3 .1E-05 O.OE+00 O.OE+00362 LOCA SBLl 0 4 0 0 3 .1E-05 0VRFD6 1 . OE-02 3 .1E-07 1.4E-06 4 .3E-13363 LOCA SBLl 0 4 0 0 3.1E-05 0VRFD7 3 .6E-03 l . l E - 0 7 l.OE-07 l . l E - 1 4364 LOCA SBLl 0 2 0 0 8 .7E-06 PSBG2 9.9E-01 8 .6E-06 l.OE-07 8.6E-13365 LOCA SBLl 0 2 0 0 8.7E-06 PSBG2 l.OE-02 8 .7E-08 l.OE-07 8.7E-15366 LOCA SBLl 1 0 0 0 1.2E-02 PSBG5 9 . 9E-01 1.2E-02 l.OE-07 1 . 2E-09367 LOCA SBLl 1 0 0 0 1 . 2E-02 TBVG6 l.OE-02 1.2E-04 1.7E-06 2.0E-10368 LOCA SBLl 1 0 0 1 2.9E-04 PSBG5 9.9E-01 2 . 9E-04 1 . OE-07 2.9E-11369 LOCA SBLl 1 0 0 1 2 .9E-04 TBVG6 l.OE-02 2.9E-06 1.7E-06 4 .9E-12370 LOCA SBLl 1 0 0 2 7.5E-04 PSBG5 9.9E-01 7.4E-04 1 . OE-07 7.4E-11371 LOCA SBLl 1 0 0 2 7.5E-04 TBVG6 l.OE-02 7.5E-06 1.7E-06 1.3E-11

F . 8

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)372 LOCA SBLl 1 0 1 0 1.3E-05 PSBG5 9.9E-01 1 . 3E-05 l.OE-07 1.3E-12373 LOCA SBLl 1 0 1 0 1.3E-05 TBV66 l.OE-02 1.3E-07 1.7E-06 2.2E-13374 LOCA SBLl 1 3 0 0 1.7E-05 PSBG5 9.9E-01 1 . 7E-05 l.OE-07 1.7E-12375 LOCA SBLl 1 3 0 0 1 . 7E-05 TBVG6 l.OE-02 1.7E-07 1 . 7E-06 2.9E-13376 LOCA SBLl 1 4 0 0 7.7E-05 PSBG5 9.9E-01 7.6E-05 l.OE-07 7.6E-12377 LOCA SBLl 1 4 0 0 7 . 7E-05 TBVG6 l.OE-02 7.7E-07 1 . 7E-06 1.3E-12378 LOCA SBLl 1 4 0 2 3.6E-06 PSBG5 9.9E-01 3.6E-06 l.OE-07 3.6E-13379 LOCA SBLl 1 4 0 2 3 . 6E-06 TBVG6 1 . OE-02 3.6E-08 1 . 7E-06 6.1E-14380 LOCA SBLl 1 4 0 2 3.6E-06 TBVG6 3.6E-03 1.3E-08 1.7E-06 2.2E-14381 LOCA SBLl 1 1 0 0 3 . 7E-04 TBVG6 9.9E-01 3.7E-04 1 . 7E-06 6.3E-10382 LOCA SBLl 1 1 0 0 3.7E-04 TBVG6 l.OE-02 3 .7E-06 1.7E-06 6.3E-12383 LOCA SBLl 1 1 0 1 8.2E-06 TBVG6 9.9E-01 8.1E-06 1 . 7E-06 1.4E-11384 LOCA SBLl 1 1 0 1 8.2E-06 TBVG6 l.OE-02 8 .2E-08 1.7E-06 1.4E-13385 LOCA SBLl 1 1 0 2 2 . lE-05 TBVG6 9.9E-01 2.1E-05 1 . 7E-06 3.6E-11386 LOCA SBLl 1 1 0 2 2.1E-05 TBVG6 l.OE-02 2 .1E-07 1.7E-06 3.6E-13387 LOCA SBLl 2 0 0 0 1 . 4E-04 PSBG5 9.9E-01 1.4E-04 l.OE-07 1.4E-11388 LOCA SBLl 2 0 0 0 1.4E-04 TBVG6 l.OE-02 1.4E-06 1.7E-06 2.4E-12389 LOCA SBLl 2 0 0 2 7 . 6E-06 PSBG5 9.9E-01 7 .5E-06 l.OE-07 7.5E-13390 LOCA SBLl 2 0 0 2 7.6E-06 TBVG6 l.OE-02 7.6E-08 1.7E-06 1.3E-13391 LOCA SBLl 2 1 0 0 3.5E-06 TBVG6 9.9E-01 3 .5E-06 1 . 7E-06 6.0E-12392 LOCA SBLl 2 1 0 0 3.5E-06 TBVG6 l.OE-02 3 .5E-08 1.7E-06 6.0E-14393 LOCA SBLl 3 0 0 0 1 . 3E-03 TBVGIO 9.9E-01 1.3E-03 l.OE-05 1.3E-08394 LOCA SBLl 3 0 0 0 1.3E-03 TBVGIO l.OE-02 1.3E-05 l.OE-05 1.3E-10395 LOCA SBLl 3 0 0 1 3.0E-05 TBVGIO 9.9E-01 3 .0E-05 l.OE-05 3.0E-10396 LOCA SBLl 3 0 0 1 3.0E-05 TBVGIO l.OE-02 3 .0E-07 l.OE-05 3.0E-12397 LOCA SBLl 3 0 0 2 8.3E-05 TBVGIO 9.9E-01 8 .2E-05 l.OE-05 8.2E-10398 LOCA SBLl 3 0 0 2 8.3E-05 TBVGIO l.OE-02 8 .3E-07 l.OE-05 8.3E-12399 LOCA SBLl 3 0 1 0 1.4E-06 TBVGIO 9.9E-01 1.4E-06 1 . OE-05 1.4E-11400 LOCA SBLl 3 0 1 0 1.4E-06 TBVGIO l.OE-02 1.4E-08 l.OE-05 1.4E-13401 LOCA SBLl 3 3 0 0 1.9E-06 TBVGIO 9.9E-01 1.9E-06 l.OE-05 1.9E-11402 LOCA SBLl 3 3 0 0 1 . 9E-06 TBVGIO l.OE-02 1.9E-08 l.OE-05 1.9E-13403 LOCA SBLl 3 4 0 0 7.8E-06 TBVGIO 9.9E-01 7.7E-06 1 . OE-05 7.7E-11404 LOCA SBLl 3 4 0 0 7.8E-06 TBVGIO l.OE-02 7.8E-08 l.OE-05 7.8E-13405 LOCA SBLl 3 4 0 0 7.8E-06 TBVGIO 3.6E-03 2.8E-08 l.OE-05 2.8E-13406 LOCA SBLl 3 1 0 0 4.0E-05 TBVGIO 9.9E-01 4.0E-05 l.OE-05 4.0E-10407 LOCA SBLl 3 1 0 0 4.0E-05 TBVGIO l.OE-02 4 .0E-07 l.OE-05 4.0E-12408 LOCA SBLl 3 1 0 2 2.1E-06 TBVGIO 9.9E-01 2.1E-06 l.OE-05 2,1E-11409 LOCA SBLl 3 1 0 2 2.1E-06 TBVGIO l.OE-02 2.1E-08 l.OE-05 2.1E-13410 LOCA SBLl 4 0 0 0 9.1E-06 TBVGIO 9.9E-01 9.0E-06 l.OE-05 9.0E-11411 LOCA SBLl 4 0 0 0 9.1E-06 TBVGIO l.OE-02 9.1E-08 1 . OE-05 9.1E-13412 LOCA SBLl 5 0 0 0 6.6E-06 TBVGIO 9.9E-01 6.5E-06 l.OE-05 6.5E-11413 LOCA SBLl 5 0 0 0 6.6E-06 TBVGIO l.OE-02 6 . 6E-08 l.OE-05 6.6E-13414 LOCA SBLl 6 0 0 0 7.3E-06 MSLB7 9.9E-01 7 .2E-06 6.2E-04 4.5E-09415 LOCA SBLl 6 0 0 0 7 . 3E-06 TBVG9 l.OE-02 7.3E-08 2 . OE-03 1.5E-10416 RES SBLl 7.8E-05 TBVG9 l.OE+00 7.8E-05 2.0E-03 1.6E-07417 LOCA SBL2 0 0 0 0 8 . 2E-03 PSBGl l.OE+00 8 .2E-03 l.OE-07 8.2E-10418 LOCA SBL2 0 0 1 0 l.OE-05 PSBGl l.OE+00 l.O E-05 l.OE-07 l.OE-12419 LOCA SBL2 0 1 0 0 2 . 6E-04 PSBG2 9.9E-01 2.6E-04 l.OE-07 2.6E-11420 LOCA SBL2 0 1 0 0 2.6E-04 PSBG4 l.OE-02 2 .6E-06 1.3E-03 3.4E-09421 LOCA SBL2 0 4 0 0 2 . 7E-06 NONE 9.9E-01 2.7E-06 O.OE+OO O.OE+OO422 LOCA SBL2 0 4 0 0 2.7E-06 0VRFD6 l.OE-02 2 . 7E-08 1.4E-06 3.8E-14423 LOCA SBL2 0 4 0 0 2.7E-06 0VRFD7 3.6E-03 9 .7E-09 l.OE-07 9.7E-16424 LOCA SBL2 0 2 0 0 1 . OE-06 PSBG2 l.OE+00 1 . OE-06 l.OE-07 l.OE-13

F . 9

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)|425 LOCA SBL2 1 0 0 0 1.2E-03 PSBG5 9.9E-01 1 . 2E-03 l.OE-07 1 . 2 E - l l426 LOCA SBL2 1 0 0 0 1 . 2E-03 TBVG6 l.OE-02 1.2E-05 1.7E-06 2.0E-11427 LOCA SBL2 1 3 0 0 2.1E-06 PSBG5 9.9E-01 2.1E-06 l.OE-07 2.1E-13428 LOCA SBL2 1 3 0 0 2.1E-06 TBVG6 l.OE-02 2 . lE-08 1 . 7E-06 3.6E-14429 LOCA SBL2 1 4 0 0 6.9E-06 PSBG5 9.9E-01 6.8E-06 l.OE-07 6.8E-13430 LOCA SBL2 1 4 0 0 6.9E-06 TBVG6 l.OE-02 6 . 9E-08 1 . 7E-06 1.2E-13431 LOCA SBL2 1 4 0 0 6.9E-06 TBVG6 3.6E-03 2 . 5E-08 1 . 7E-06 4.2E-14432 LOCA SBL2 1 1 0 0 4 . OE-05 TBVG6 9.9E-01 4 . OE-05 1 . 7E-06 6.8E-11433 LOCA SBL2 1 1 0 0 4.0E-05 TBVG6 l.OE-02 4.0E-07 1 . 7E-06 6.8E-13434 LOCA SBL2 2 0 0 0 1.4E-05 PSBG5 9.9E-01 1.4E-05 l.OE-07 1.4E-12435 LOCA SBL2 2 0 0 0 1.4E-05 TBVG6 l.OE-02 1.4E-07 1 . 7E-06 2.4E-13436 LOCA SBL2 3 0 0 0 1.4E-04 TBVGIO 9.9E-01 1.4E-04 l.O E-05 1.4E-09437 LOCA SBL2 3 0 0 0 1.4E-04 TBVGIO l.OE-02 1.4E-06 l.OE-05 1.4E-11438 LOCA SBL2 3 1 0 0 4 . OE-06 TBVGIO 9.9E-01 4.0E-06 l.OE-05 4.0E-11439 LOCA SBL2 3 1 0 0 4 . OE-06 TBVGIO l.OE-02 4.0E-08 l.OE-05 4.0E-13440 RES SBL2 1.8E-05 PSBG4 l.OE+00 1.8E-05 1.3E-03 2.3E-08441 SGTR SGTR 0 0 0 0 8.2E-03 SGTR l.OE+00 8.2E-03 l.O E-07 8.2E-10442 SGTR SGTR 0 0 1 0 l.OE-05 SGTR l.OE+00 l.OE-05 l.OE-07 l.OE-12443 SGTR SGTR 0 1 0 0 2.6E-04 PSBG2 9.9E-01 2 . 6E-04 l.OE-07 2.6E-11444 SGTR SGTR 0 1 0 0 2.6E-04 PSBG4 l.OE-02 2.6E-06 1 . 3E-03 3.4E-09445 SGTR SGTR 0 4 0 0 2 . 7E-06 NONE 9.9E-01 2.7E-06 O.OE+OO O.OE+OO446 SGTR SGTR 0 4 0 0 2 . 7E-06 0VRFD6 l.OE-02 2 . 7E-08 1.4E-06 3.8E-14447 SGTR SGTR 0 4 0 0 2.7E-06 0VRFD7 3.6E-03 9 . 7E-09 1 . OE-07 9.7E-16448 SGTR SGTR 0 2 0 0 l.O E-06 PSBG2 9.9E-01 1 .OE-06 l.OE-07 l.OE-13449 SGTR SGTR 0 2 0 0 l.OE-06 PSBG2 l.OE-02 l.OE-08 l.OE-07 l.OE-15450 SGTR SGTR 1 0 0 0 1 . 2E-03 PSBG5 9.9E-01 1 . 2E-03 l.O E-07 1.2E-10451 SGTR SGTR 1 0 0 0 1.2E-03 TBVG6 l.OE-02 1 . 2E-05 1.7E-06 2.0E-11452 SGTR SGTR 1 3 0 0 2.1E-06 PSBG5 9.9E-01 2.1E-06 l.OE-07 2.1E-13453 SGTR SGTR 1 3 0 0 2.1E-06 TBVG6 l.OE-02 2.1E-08 1 . 7E-06 3.6E-14454 SGTR SGTR 1 4 0 0 6 . 9E-06 PSBG5 9.9E-01 6.8E-06 l.OE-07 6.8E-13455 SGTR SGTR 1 4 0 0 6.9E-06 TBVG6 l.OE-02 6.9E-08 1.7E-06 1.2E-13456 SGTR SGTR 1 4 0 0 6.9E-06 TBVG4 3.6E-03 2.5E-08 2.0E-03 5.0E-11457 SGTR SGTR 1 1 0 0 4.0E-05 PSBG5 9.9E-01 4.0E-05 l.OE-07 4.0E-12458 SGTR SGTR 1 1 0 0 4.0E-05 TBVG6 1 . OE-02 4.0E-07 1 . 7E-06 6.8E-13459 SGTR SGTR 2 0 0 0 1.4E-05 PSBG5 9.9E-01 1.4E-05 l.OE-07 1.4E-12460 SGTR SGTR 2 0 0 0 1.4E-05 TBVG6 l.OE-02 1.4E-07 1 . 7E-06 2.4E-13461 SGTR SGTR 3 0 0 0 1.4E-04 TBVGIO 9.9E-01 1.4E-04 l.OE-05 1.4E-09462 SGTR SGTR 3 0 0 0 1.4E-04 TBVGIO 1 . OE-02 1 . 4E-06 1 . OE-05 1.4E-11463 SGTR SGTR 3 1 0 0 4.0E-06 TBVGIO 9.9E-01 4.0E-06 l.OE-05 4.0E-11464 SGTR SGTR 3 1 0 0 4 . OE-06 TBVGIO l.OE-02 4.0E-08 1 . OE-05 4.0E-13465 RES SGTR 1.8E-05 TBVG4 l.OE+00 1.8E-05 2.0E-03 3.6E-08466 NORM SI 0 0 0 0 7 . 6E-03 NONE l.OE+00 7.6E-03 O.OE+OO O.OE+OO467 LOCA SI 0 0 0 1 1.9E-04 PSBGl 1 . OE+00 1.9E-04 l.OE-07 1.9E-11468 LOCA SI 0 0 0 2 5 . OE-04 PSBGl l.OE+00 5.0E-04 l.OE-07 5.0E-11469 FW SI 0 1 0 0 2.4E-04 0VRFD3 l.OE+00 2.4E-04 l.OE-07 2.4E-11470 LOCA SI 0 1 0 1 5.4E-06 PSBG2 9.9E-01 5.3E-06 l.OE-07 5.3E-13471 LOCA SI 0 1 0 1 5.4E-06 PSBG2 l.OE-02 5.4E-08 l.OE-07 5.4E-15472 LOCA SI 0 1 0 2 1 . 5E-05 PSBG2 9.9E-01 1.5E-05 l.OE-07 1.5E-12473 LOCA SI 0 1 0 2 1.5E-05 PSBG2 l.OE-02 1.5E-07 l.OE-07 1.5E-14474 FW SI 0 4 0 0 2.2E-06 NONE 9.9E-01 2 . 2E-06 O.OE+OO O.OE+OO475 FW SI 0 4 0 0 2 . 2E-06 0VRFD6 l.OE-02 2.2E-08 1.4E-06 3.1E-14476 FW SI 0 4 0 0 2.2E-06 0VRFD7 3.6E-03 7.9E-09 l.OE-07 7.9E-16477 SL SI 1 0 0 0 1.2E-03 TBVG2 9.9E-01 1.2E-03 l.OE-07 1.2E-10

F. IO

REC TYPE INIT SPC FWS ECC PPC EFREQ TRANS HF TFREQ P(F |T ) P(TWC)478 SL SI 1 0 0 0 1.2E-03 TBVGl l.OE-02 1.2E-05 4.0E-07 4.8E-12479 SL SI 1 0 0 1 2 , 8E-05 PSBG5 9.9E-01 2.8E-05 l.OE-07 2.8E-12480 SL SI 1 0 0 1 2.8E-05 TBVG6 l.OE-02 2.8E-07 1.7E-06 4.8E-13481 SL SI 1 0 0 2 7 .2E-05 PSBG5 9.9E-01 7.1E-05 l.OE-07 7.1E-12482 SL SI 1 0 0 2 7 .2E-05 TBVG6 l.OE-02 7.2E-07 1.7E-06 1.2E-12483 SS SI 1 4 0 0 5 , 7E-06 TBVG2 9.9E-01 5.6E-06 l.OE-07 5.6E-13484 SS SI 1 4 0 0 5 . 7E-06 TBVGl l.OE-02 5.7E-08 4.0E-07 2.2E-14485 SS SI 1 4 0 0 5 .7E-06 TBVGl 3.6E-03 2.1E-08 4.0E-07 8.4E-15486 SS SI 1 1 0 0 3 .6E-05 TBVG3 9.9E-01 3.6E-05 l.OE-07 3.6E-12487 SS SI 1 1 0 0 3 , 6E-05 TBVG4 l.OE-02 3.6E-07 2.0E-03 7.2E-10488 SL SI 2 0 0 0 1 , 2E-05 TBVG2 9.9E-01 1.2E-05 l.OE-07 1.2E-12489 SL SI 2 0 0 0 1.2E-05 TBVGl l.OE-02 1.2E-07 4.0E-07 4.8E-14490 SL SI 3 0 0 0 1.3E-04 TBVG5 9.9E-01 1.3E-04 5.2E-06 6.8E-10491 SL SI 3 0 0 0 1 . 3E-04 TBVG5 l.O E-02 1.3E-06 5.2E-06 6.8E-12492 SL SI 3 0 0 1 3.1E -06 TBVGIO 9.9E-01 3.1E-06 l.OE-05 3.1E-11493 SL SI 3 0 0 1 3 .1E-06 TBVGIO l.O E-02 3.1E-08 l.OE-05 3.1E-13494 SL SI 3 0 0 2 7.1E-06 TBVGIO 9.9E-01 7.0E-06 l.OE-05 7.0E-11495 SL SI 3 0 0 2 7 , lE -06 TBVGIO l.OE-02 7.1E-08 l.OE-05 7.1E-13496 SS SI 3 1 0 0 3 .3E -06 TBVG9 9.9E-01 3.3E-06 2.0E-03 6.6E-09497 SS SI 3 1 0 0 3 . 3E-06 TBVG9 l.OE-02 3.3E-08 2.0E-03 6.6E-11498 RES SI 3 .9E-05 TBVG4 l.OE+00 3.9E-05 2.0E-03 7.8E-08

F . l l

APPENDIX G

RESPONSES TO UTILITY COMMENTS

The m a te r i a l p r e s e n te d in t h i s r e p o r t I s p a r t o f an e v a lu a t io n e f f o r t to p ro v id e In fo rm a t io n on th e u n re so lv e d s a f e t y I s s u e o f p r e s s u r i z e d therm al shock (PTS). Because PTS I s an u n re s o lv e d s a f e t y I s s u e , NRG r e q u i r e s t h a t a l i s t o f I n d u s t r y comments on th e r e p o r t and th e changes which were made as a r e s u l t o f th o s e comments be p ro v id ed a s an appendix to th e r e p o r t . The m a te r i a l p r e s e n te d In t h i s appendix responds to t h a t re q u ire m e n t . The comments a r e l i s t e d and d is c u s s e d by c h a p te r w ith comments on t h e a p p e n d i c e s d i s c u s s e d a lo n g w ith th e a p p r o p r ia te c h a p te r s . Only th o s e comments c o n s id e re d to be p e r t i n e n t to th e PTS s tu d y a re a d d re s se d ; t h a t I s , comments s im ply p o in t in g ou t gram m atical o r s p e l l i n g e r r o r s a r e n o t In c lu d e d .

G eneral Comments

1. T h is r e p o r t r e p r e s e n t s th e r e s u l t s o f a s u b s t a n t i a l l e v e l o f e f f o r t over th e p a s t th r e e y e a r s to e v a lu a te th e r i s k o f P r e s s u r i z e d Thermal Shock a t Oconee N uclea r S t a t i o n , U nit 1. As w r i t t e n th e r e p o r t la c k s c o n s i s te n c y and r e a d a b i l i t y . An enormous w e a l th o f In fo rm a t io n Is p ro v id e d , much o f which i s I n c o n s e q u e n t ia l t o th e f i n a l r e s u l t .

Response: We would ag re e t h a t th e r e p o r t te rm in o lo g y I s I n c o n s i s t e n t andth e r e a d a b i l i t y cou ld be g r e a t l y Improved. However, I t was de term ined t h a t our e f f o r t s would be more w is e ly s p e n t In com ple ting th e C a lv e r t C l i f f s and H. B. Robinson r e p o r t s s in c e th e s e s t u d i e s r e f l e c t a more r e f i n e d e v a lu a t io n p ro c e s s . Thus, v e ry l i t t l e e f f o r t was made to Improve th e r e a d a b i l i t y o f th e r e p o r t . We would ag re e t h a t much o f th e Inform a­t i o n p r e s e n t e d In t h e r e p o r t I s I n c o n s e q u e n t i a l t o t h e f i n a l r e s u l t . However, I t I s our o p in io n t h a t th e p ro c e s s used to perform th e e v a lu a t io n and a d e t a i l e d d i s c u s s io n o f th e assum ptions made In th e e v a l u a t i o n I s as Im p o r tan t I f n o t more so th a n th e a c t u a l f i n a l r e s u l t I t s e l f . The enormous amount o f In fo rm a t io n I s n e c e s s a ry to p ro v id e : th eapproach used to perform th e e v a l u a t i o n , th e d a ta used In th e e v a lu a t io n , assum ptions made In I d e n t i f y i n g seq u en ce s , and our u n d e rs ta n d in g o f howth e p l a n t responds to c e r t a i n e v e n t s . W ithout t h i s In fo rm a t io n th eq u a l i t y o f th e f i n a l r e s u l t can n o t be d e te rm in ed .

2. The c h a r a c t e r i z a t i o n o f th e f req u en cy (4.5E-6/RY) o f a TWC as a b e s t e s t im a te I s n o t a p p r o p r i a t e from two p e r s p e c t iv e s : (1) A rev iewo f th e r e p o r t I n d i c a t e s c o n se rv a t is m s t h a t on b a lan ce would b ia s th e c i t e d TWC freq u en cy v a lu e tow ards an upper bound and (2) th e l a rg e u n c e r t a i n t y o f a f a c t o r o f 100 and th e r e f o r e a range o f t e n thousand d i l u t e s th e co n f id e n ce o f 4.5E-6/RY as b e in g a b e s t e s t im a te .

Response: A f te r th e com ple tion o f th e C a lv e r t C l i f f s and H. B. Robinsona n a l y s i s , th e Oconee e v a l u a t i o n was rev iew ed In l i g h t of th e Improvements In th e e v a lu a t io n te c h n iq u e s . Both c o n s e rv a t iv e and n o n -c o n s e rv a t iv e f a c t o r s were I d e n t i f i e d In th e Oconee a n a l y s i s . As s t a t e d In th e comment. I t d id appea r t h a t th e b a la n c e o f th e s e f a c t o r s appeared to be In th e c o n s e r v a t iv e d i r e c t i o n . However, w i th o u t r e d o in g th e c a l c u l a t i o n s th e a c t u a l b e s t e s t im a te v a lu e cou ld n o t be d e te rm in ed . The f a c t o r of100 g iven f o r th e u n c e r t a i n t y v a lu e I s a 95% v a lu e . T h is v a lu e maybe somewhat h igh due to th e u n r e a l i s t i c u n c e r t a i n t i e s used In th e n e g a t iv e d i r e c t i o n o f th e te m p e ra tu re p r o f i l e s and th e double co u n t in g e f f e c t f o r v e ry h ig h f law d e n s i t y v a lu e s . However, In l i g h t o f o th e r

G.l

f a c t o r s , u se o f e r r o r f a c t o r s a s 99S5 v a lu e s r a t h e r th an 95* v a lu e s , e t c . , th e u n c e r t a i n t y v a lu e s a r e n o t u n r e a l i s t i c .

3. A ll r e f e r e n c e s o f th e d e s ig n o f o th e r B&W NSSS p l a n t d e s ig n s sh o u ld be d e l e t e d . We have no c u r r e n t knowledge o f th e p r e s e n t d e s ig n o f any o th e r p l a n t and to s t a t e t h a t a p a r t i c u l a r Oconee f e a t u r e I s o r I s n o t p a r t o f a n o th e r p l a n t ' s d e s ig n I s n o t a s ta te m e n t o f f a c t .

Response: We would ag re e t h a t th e c o n c lu s io n s , m i t i g a t in g a c t i o n s ,e t c . sh o u ld be d i s c u s s e d w ith r e s p e c t t o Oconee s in c e t h a t I s th e p l a n tfrom which th e d a t a was o b ta in e d . In fe re n c e o f c o n d i t io n s a t o th e r B&Wp l a n t s based on Oconee r e s u l t s w i th o u t a rev iew o f th e o th e r p l a n t s I s I n a p p r o p r ia te . R e fe re n ces to B&W p l a n t s In g e n e r a l used In t h i s c o n te x t were changed to r e f e r on ly to Oconee.

4 . R e p e a te d r e f e r e n c e I s made to th e b e s t e s t im a te TWC v a lu e o f4.5E-6/RY. I t sh o u ld be made c l e a r t h a t t h i s v a lu e on ly a p p l i e s a t 32 EFPY and t h a t p r i o r to t h a t tim e th e TWC p r o b a b i l i t y I s low er.

Response: We ag re e w i th th e comment. The 32 EFPY d e s ig n a t io n was addedto th e d i s c u s s io n s o f th e b e s t e s t im a te TWC v a lu e .

C hapter 1 .0 Comments

5. The s ta t e m e n t r e g a r d in g f u t u r e use o f th e Oconee PTS model Inth e f i r s t p a ra g ra p h I s I n a p p r o p r ia te . I t s e rv e s no u s e f u l p u rpose , and I s c o n t r a r y t o t h e Im p lied agreem ent we had. Duke r e q u e s t s t h a t I t be d e l e t e d .

Response: The s e n te n c e was d e l e te d from th e t e x t .

C hapter 2 .0 Comments

6. The v e s s e l downcomer I s between th e v e s s e l and th e the rm a l s h i e l d , n o t th e co re b a r r e l .

Response: We concu r . The change was made In th e t e x t .

7 . The c o o l a n t In v e n to ry c o n t r o l system adds o r w ithdraw s c o o la n tbased on I n d ic a t e d In v e n to ry , n o t r e a c t o r power.

Response: We co n cu r . The change was made In th e t e x t .

8. I t sh o u ld be made c l e a r t h a t s a f e t y I n j e c t i o n I s used t o p re v e n t f u e lo v e rh e a t in g o n ly under a c c id e n t c o n d i t io n s .

Response: We a g re e . The t e x t was changed to make t h i s p o in t .

9. The co n d en sa te t r a i n I s I n c o r r e c t l y d e s c r ib e d In th e second p a r a ­g rap h . The c o n d en sa te p a th I s F H e a te r s , E H e a te r s , D H e a te r s , C H ea te r D rain C o o le rs , and C H e a te r s . The D H ea te rs a r e n o t d r a in c o o l e r s .

Response: We co n cu r . Text was r e v i s e d t o r e f l e c t t h i s comment.

G.2

10. The condensa te b o o s te r pumps a r e cap a b le o f d e l i v e r i n g feed w ate r a t 550 p s lg . n o t 600 p s lg .

Response: We a g re e . The change was made In th e t e x t .

11. The EFW pumps a r e a c tu a te d I f th e MFW pumps t r i p o f f o r I f MFW p r e s s u r e d rops below 750 p s lg .

Response: We a g re e . The change was made In th e t e x t .

12. S e c t io n 2 . 2 .3 . 3 i s co m p le te ly e r ro n e o u s . ICS no lo n g e r c o n t r o l s EFW. EFW i s co m p le te ly s e p a r a t e from ICS and i s i n i t i a t e d and c o n t r o l l e d by a s a f e t y - r e l a t e d system .

Response: We a g re e . The r e f e r e n c e to th e ICS system was in e r r o r . Thisr e f e r e n c e was removed from th e t e x t .

13. In S e c t io n 2 . 2 .4 , no b a s i s has been p ro v id ed to su p p o r t th e s ta te m e n t t h a t t h e r e i s a h i s t o r i c a l r e c o rd o f s in g l e f a i l u r e s o f su p p o r t system s c a u s in g o v e rc o o l in g t r a n s i e n t s .

Response: We a g re e . The t e x t was changed to r e f l e c t th e p o t e n t i a lim portance o f su p p o r t system s r a t h e r th a n any h i s t o r i c a l d a ta .

14. Secondary s id e p r e s s u r e sh o u ld be 1010 n o t 1025 p s lg .

Response: We a g re e . Change in th e t e x t was made.

15 . I t i s a s s e r t e d t h a t LOCAs can g e n e ra te s ta g n a te d flow regim es t h a t can c o n t r i b u t e t o " l o c a l i z e d r a p i d cooldown o f th e r e a c t o r v e s s e l . " Y et, in th e l a s t s e n te n c e o f t h i s s e c t i o n i t i s s t a t e d " th e v en t v a lv e s , t h e r e f o r e , promote c o n t in u e d c i r c u l a t i o n o f c o o la n t th rough th e core re g io n a s w ell a s p ro v id e warm w a te r to mix w ith HPI flow s e n t e r i n g th e downcomer r e g io n . " T h is l a t t e r d i s c u s s io n i s r e p r e s e n t a t i v e o f th e t r u e s i t u a t i o n and would seem to c o n t r a d i c t th e f i r s t s e n te n c e .

Response: The f i r s t s e n te n c e was meant t o imply t h a t in g e n e ra l LOCAshave a p o t e n t i a l to g e n e ra te s t a g n a t e d flow regim es t h a t can c o n t r i b u t e t o l o c a l i z e d r a p id cooldown o f a r e a c t o r v e s s e l . The r e s t o f th e d i s c u s s io n goes on to show t h a t a t Oconee th e o p e ra t io n o f th e ven t v a lv e s prom otes c i r c u l a t i o n and t h e r e f o r e p re c lu d e s o r g r e a t l y l i m i t s th e p o t e n t i a l f o r s ta g n a te d flow reg im es . Some rew ord ing o f t h i s s e c t i o n was made to avo id m isu n d e rs ta n d in g s .

C hapter 3 Comments

16. There a r e two TSVs on each b ran ch , n o t fo u r .

Response: We a g re e . The change was made in th e t e x t .

17. The r e p o r t s t a t e s t h a t secondary u p s e t s w i l l te n d to mask a PORV LOCA, and goes on t o assume t h a t th e o p e r a to r s w i l l do n o th in g to m i t i g a t e such an ev en t u n t i l steam g e n e r a to r h e a t removal c a p a c i ty i s r e s t o r e d . T h is i s c l e a r l y i n c o n s i s t e n t w ith post-TMI o p e r a to r t r a i n i n g

G. 3

program s. We do n o t b e l i e v e t h i s t a k e s In to accoun t th e a d d i t i o n of su b c o o l in g m argin m o n ito rs and co re e x i t therm ocouples to th e c o n t ro l rooms.

Response: We concur t h a t th e assum ption made was a c o n s e rv a t iv e approachand th e r e p o r t was changed to make t h i s p o in t .

C hap ter 4 Comments

18. The emergency feed w ate r system c o n t ro l i s n o t p a r t o f th e ICS.

Response: The s ta te m e n t as p r e s e n te d in th e t e x t i s in r e f e r e n c eto th e o v e r a l l c o n t ro l system n o t j u s t th e ICS. However t o avo id c o n fu s io n a d d i t i o n a l w ording was added to c l e a r l y i n d i c a t e t h a t th e EFW i s no t p a r t o f th e ICS.

19. The l a r g e u n c e r t a i n t i e s shou ld have no e f f e c t on th e b e s t e s t im a te v a lu e . A ll th e y can do i s a f f e c t o v e r a l l u n c e r t a in t y .

Response: We a g re e . The b e s t e s t im a te v a lu e shou ld n o t have beenchanged. Thus, th e use o f th e a d ju s t e d th e rm a l -h y d ra u l ic t r a n s i e n t i s i n c o n s i s t e n t w i th th e t r e a tm e n t o f u n c e r t a i n t y l a t e r in th e r e p o r t . The r e s u l t o f t h i s in c o n s i s t e n c y i s a c o n s e r v a t iv e b ia s f o r t h i s t r a n s i e n t . A se n te n c e was added in th e t e x t t o make t h i s p o in t .

20. The sequence o f e v e n ts i n c o r r e c t l y i n d i c a t e s t h a t EFW i s be ing s t a r t e d on low SG l e v e l .

Response: We a g re e . The EFW flow i n i t i a t e s a t th e tim e in d i c a t e d . However, th e pumps had p r e v io u s ly s t a r t e d . R eference to th e pumps s t a r t i n g a t in d i c a t e d tim e was removed.

2 1 . F o r f a i l u r e o f two tu r b i n e bypass v a lv e s a t f u l l power o th e r s i g n i f i c a n t f e a t u r e s o f th e t r a n s i e n t in c lu d e : O p era to r does no t i s o l a t e / c o n t r o l fe e d w a te r , h ig h l e v e l t r i p f a i l s , MFW i s n o t r e a l ig n e d upon RCP t r i p .

R e s p o n s e : We would ag ree t h a t " o p e r a to r does n o t i s o l a t e / c o n t r o lfeed w ate r" i s a f e a t u r e which shou ld have been i d e n t i f i e d . T h is f e a t u r e was in c lu d e d in th e d i s c u s s io n o f th e t r a n s i e n t . The h igh l e v e l t r i p was n o t assumed to f a i l and in f a c t t r i p p e d th e pumps a t 6 0 .7 seconds as i n d i c a t e d in t a b l e 4 .1 5 . F u r th e rm o re , MFW was r e a l ig n e d upon RCP t r i p as i n d i c a te d in t a b l e 4 .1 5 .

22. The sequence o f e v e n ts shows MFW pump t r i p a t 61 seconds , b u t no EFW a c t u a t i o n u n t i l 210 seconds . T h is does n o t make s e n se .

Response: The r e f e r e n c e to pump a c t u a t i o n a t 209 seconds was meant tor e f e r to a c t u a l EFW flow w ith pumps hav ing been a c tu a te d fo l lo w in g MFW pump t r i p . The t e x t was changed to make t h i s p o in t .

23. The e x t r a p o l a t i o n s o f te m p e ra tu re f o r s e v e r a l o f th e sequences a re u n r e a l i s t i c in a p h y s ic a l sen se and a r e s u b s t a n t i a l l y c o n s e r v a t iv e .

G. 4

Response: We would ag re e t h a t th e e x t r a p o la t e d te m p e ra tu re s appea r to bec o n s e r v a t iv e . However, In l i g h t o f th e p o t e n t i a l c o o l in g o f th e HPI and EFW system s th e le v e l o f c o n se rv a t ism cou ld n o t be de term ined w ith o u t a th e rm a l - h y d r a u l ic c a l c u l a t i o n o f th e com plete two hour a n a l y s i s p e r io d . S ince t h i s was n o t done, th e cu rv es p r e s e n te d In th e r e p o r t do r e f l e c t our b e s t e s t im a te based on th e a v a i l a b l e d a ta and th u s no change was made In t h e d i s c u s s i o n o f th e th e rm a l - h y d r a u l ic s a s s o c ia t e d w ith th e se s e q u e n c e s .

24. There were s e v e r a l g e n e ra l comments made by Duke Power C o rpo ra tion co n ce rn in g what th e y p e rc e iv e d to be c o n s id e r a b le c o n se rv a t ism s used In th e e x t r a p o l a t i o n p ro c e s s .

Response: A lthough ORNL I n t u i t i v e l y ag reed w ith many o f th e s e comments,changes In th e r e p o r t cou ld n o t be made w i th o u t s p e c i f i c d a ta . This d a ta cou ld n o t be o b ta in e d w ith o u t a g r e a t d ea l o f f u r t h e r th e rm a l-h y d ra u l ic c a l c u l a t i o n s . As a r e s u l t , th e d a ta a s p re s e n te d In c h a p te r 4 r e p r e s e n t s th e o n ly d a t a a v a i l a b l e and th u s must be used as b e s t e s t im a te Inform a­t i o n .

25. R efe ren ce I s made to a s tu d y "under I n v e s t i g a t i o n " . The s p e c i f i c s shou ld be p ro v id e d as a fo o tn o te o r r e f e r e n c e .

Response: The r e f e r e n c e was made to r e s e a r c h be ing perform ed a t P a c i f i cN orthw est L a b o r a to r i e s . I t was d e c id e d , however, t h a t r e f e r e n c e to t h i s s tu d y d e t r a c t e d from th e p o in t b e in g made In th e t e x t and th u s th e r e f e r e n c e was d e l e te d .

26. I t seems t h a t s u b s t a n t i a l u n j u s t i f i e d u n c e r t a in t y I s b e in g a p p l ie d to f law d e n s i t y d i s t r i b u t i o n .

Response: The f law d e n s i t y d i s t r i b u t i o n I s based upon th e e n g in e e r in gjudgement o f our e x p e r t In f r a c t u r e m echan ics . The d i s t r i b u t i o n used was n o t In te n d e d a s a t y p i c a l d i s t r i b u t i o n f o r a p a r t i c u l a r r e a c t o r v e s s e l . I n s t e a d , I t sh o u ld be I n t e r p r e t e d as c o v e r in g th e p o p u la t io n o f a l l p o s s i b l e r e a c t o r v e s s e l s . However, th e f a c t t h a t a p a r t i c u l a r ISI d e t e c te d no n e a r s u r f a c e f law s o f conce rn to PTS does n o t n e c e s s a r i l y r e d u c e th e u n c e r t a i n t y In th e f law d e n s i t y d i s t r i b u t i o n . The ISI te c h n iq u e s used a re p ro b ab ly no t cap a b le o f d e t e c t i n g f law s In and ex te n d in g a s h o r t d i s t a n c e beyond th e c la d d in g . Thus no changes In th e t e x t were made.

27 . F o r t h e d a t a p ro v id e d In Appendix E. I n s u f f i c i e n t d e f i n i t i o n o f term s I s p ro v id ed .

Response: We ag re e t h a t In some I n s ta n c e s d e f i n i t i o n o f te rm s was no tp ro v id e d . In fo rm a t io n was added f o r th o s e term s no t p r e v io u s ly d e f in e d In th e t e x t .

28. Replacem ent o f th e c u r r e n t HPI system w ith a low head system I s d i s c u s s e d . T h is Item I n d i c a t e s a l i m i t e d knowledge o f th e b ig p i c t u r e o f p l a n t s a f e t y and sh o u ld be d e l e t e d .

Response: The comment was n o t meant to be I n t e r p r e t e d as a recommenda-

G.5

t l o n f o r a change in th e Oconee d e s ig n . The purpose o f th e d i s c u s s io n was to i n d i c a t e th e i a p o r t a n c e o f th e r e p r e s s u r i z a t i o n p ro c e s s t o th e PTS phenomenon. The t e x t was changed to make t h i s p o in t c l e a r .

2 9 . The d i s c u s s i o n o f IS I i n t h i s c h a p t e r co m p le te ly ig n o re s th ef a c t t h a t such in s p e c t io n s a r e r e g u la to r y r e q u ire m e n ts .

R e s p o n s e : The i n s e r v i c e i n s p e c t i o n s d is c u s s e d in t h i s c h a p te r a red i f f e r e n t th a n th e i n s e r v i c e i n s p e c t io n s p r e s e n t l y r e q u i r e d by NRC. I twas c l e a r t h a t t h i s d i s t i n c t i o n was n o t made. The t e x t was changed toc l e a r l y p o in t o u t t h a t we were r e f e r r i n g t o improved i n s e r v i c e in s p e c t io n t e c h n iq u e s .

30. T h e rm a l-h y d ra u l ic d i s t r i b u t i o n s were assumed to be norm al, y e t th e dominant c o n t r i b u t o r s , a s p r e v io u s ly n o te d , were c o n s e r v a t iv e l y p r e d i c t e d a s e i t h e r u p p e r p r e s s u r e o r low er te m p e ra tu re bound. I t i s s im ply in c r e d i b l e t h a t a t r a n s i e n t w i th an assumed T^ o f below 212° can have an u n c e r t a i n t y t h a t would p u t th e v a lu e even low er.

Response: Even though i t a p p e a rs t h a t c o n se rv a t ism s were in c lu d e d in th eth e rm a l h y d r a u l i c a n a ly s e s , i t was n e c e s s a ry to assume a normal d i s t r i b u ­t i o n f o r th e th e rm a l - h y d r a u l i c v a r i a b l e s s in c e o n ly l i m i t e d in fo rm a t io n was a v a i l a b l e . I t shou ld be n o te d t h a t a l th o u g h th e s e c o n se rv a t is m s may be l a r g e , th e y sh o u ld n o t be i n t e r p r e t e d as a b s o lu t e upper and lower bounds o f p r e s s u r e and te m p e ra tu re . F i n a l l y , a s i g n i f i c a n t im portance i s im p l ie d to th e 212° te m p e ra tu re . T h is does n o t r e p r e s e n t a bound f o r th e steeui l i n e b re a k e v e n ts e x c e p t in th e case where steam l i n e breedc occu rs w i th s h o r t d u r a t i o n o f HPI and EFW flow . However, we would a g re e t h a t as t h e s e lo w e r t e m p e r a t u r e v a l u e s a r e r e a c h e d th e u n c e r t a i n t y in th e te m p e ra tu re v a lu e s shou ld s i g n i f i c a n t l y d e c re a se .

31. I t i s i n c r e d i b l e t h a t in l i g h t o f th e ISI t h a t have been done, th e f l a w d e n s i t y c o u l d be s u b s t a n t i a l l y h ig h e r th a n t h a t c o n s e r v a t iv e ly assumed.

R e s p o n s e : The t e x t was c h a n g e d t o em phasize th e o p in io n t h a t th ep r e s e n t ISI te c h n iq u e s in use a r e n o t s u f f i c i e n t to d e t e c t th e ty p e s o f f law s which may be im p o r ta n t t o PTS.

C hap te r 8 Comments

32. The c o n c lu s io n s imply t h a t PTS i s a s a f e t y conce rn , t h a t t h e r e i s a h ig h d eg ree o f u n c e r t a i n t y in th e n o n -c o n s e rv a t iv e d i r e c t i o n and t h a t f u r t h e r s tu d y i s r e q u i r e d in s e v e r a l a r e a s .

Response: The c o n c lu s io n s were n o t meant to imply t h a t PTS i s a s a f e t yconcern a t Oconee. In f a c t t h e o p p o s i te i s s t a t e d in th e c o n c lu s io n s s e c i t i o n s . We would a g re e t h a t th e need f o r f u r t h e r s tu d y o f c e r t a i n a r e a s o f th e a n a l y s i s may have been o v e r s t a t e d . As a r e s u l t some o f th e r e f e r e n c e s to such s t u d i e s were removed. We would s t i l l imply t h a t th e r e a r e u n c e r t a i n t i e s in th e r e s u l t s . A lthough we would i n t u i t i v e l y ag ree t h a t t h e u n c e r t a i n t y may be som ew hat h ig h in th e n o n -c o n s e rv a t iv e d i r e c t i o n due to c o n s e r v a t iv e assum ptions made in th e a n a l y s i s , t h e r e i s

G.6

no t enough s u f f i c i e n t d a ta to imply th e le v e l o f co n se rv a t ism . In l i g h t o f t h i s , no changes were made in th e u n c e r t a i n t y v a lu e s .

33. The p ro p o sa l to h e a t HPI by 50Op c o n t r a d i c t s a s ta te m e n t made in S e c t io n 6 . 3 .4 : " O v e ra l l , HPI h e a t in g c o u ld p ro v id e some sm all bu tv a r i a b l e b e n e f i t i n te rm s o f downcomer te m p e ra tu re re sp o n se " .

Response: The wording in t h i s s e c t i o n was m is le a d in g . The t e x t was changed to make th e p o in t c l e a r e r . I t i s ou r o p in io n t h a t t h e r e i s no t a c o n t r a d i c t i o n .

34. The A n t ic ip a te d T ra n s ie n t O p e ra t in g G u id e l in e s (ATOG) program now be ing implemented a t B&W p la n t s in c lu d e s o p e r a to r a c t io n s to l i m i t p rim ary system r e p r e s s u r i z a t i o n as p a r t o f th e re sp o n se and m i t ig a t io n of o v e rc o o l in g e v e n t s . T h is shou ld be acknowledged in th e NUREG i f the recommendation i s to be r e t a i n e d .

Response: R efe rence to th e ATOG program was made.

35. S e c t io n 8 . 2 .5 item (4) p ro v id e s th e u n c e r t a i n t y d i s t r i b u t i o n and s t a t e s t h a t th e Oconee PTS r i s k i s fo u r t im es h ig h e r th an th e s a f e t y g o a l . T h is shou ld be r e v i s e d to show th e i n t e g r a l r e l a t i o n s h i p w ith th e s a f e t y goa l u s in g th e p o in t e s t im a te w ith and w ith o u t th e r e s i d u a l .

Response: A f te r c a r e f u l c o n s id e r a t i o n , i t was ORNL's d e c i s io n t o removeth e d i s c u s s io n o f th e com parison o f th e 95% v a lu e and th e s a f e t y g o a l . I t was our o p in io n t h a t t h e r e i s c o n s e rv a t is m in th e 95% con fidence l e v e l . T h e re fo re , a c t u a l com parisons o f th e 95% v a lu e and th e s a f e tygoal may be m is le a d in g . As a r e s u l t , i tem (4) was d e le te d from th eco n c lu s io n s s e c t i o n .

36. In th e summary s e c t i o n o f c h a p te r 8, th e f i r s t s en ten c e i s in a p p ro ­p r i a t e and sh o u ld be removed. I t was n o t th e s t a t e d purpose o f t h i s r e p o r t to judge th e f i n a l s t a t u s o f p r e s s u r i z e d the rm al shock as a s a f e ty i s s u e .

Response: A rev iew o f th e r e f e r e n c e d s e n te n c e , i n d i c a te d t h a t co n c lu ­s io n s were im p lie d which were n o t j u s t i f i e d . The s en ten c e was d e l e te d from th e t e x t .

G.7

NDREG/CR-3770 ORNL/TM-9176 D i s t r i b u t i o n C ategory RG

INTERNAL DISTRIBUTION1 . L. S. Abbott 15. D. L. Selby2 . D. G. B a l l 16 . H. T. Trammell3 . S. B a l l 17. J . D. White4 . B. R. Bass 18 . 6 . D. Whitman5 . T. J . Burns 19. A. Zucker6 . D. G. Cacuci 2 0 . P. W. Dickson, J r . (C o n su lta n t)7 . R. D. Cheverton 2 1 . G. H. Golub (C o n su l ta n t)8 . J . S. Crowell 2 2 . R. M. H a ra l ic k (C o n su l ta n t)9 . D. M. E issen b e rg 23. D. S te in e r (C o n su l ta n t)

1 0 . G. F. F lanagan 24. C e n tra l Research L ib ra ry1 1 . F. C. M aienschein 25. Y-12 Document R ef. S e c t io n1 2 . A. P. M alinauskas 26. L a b o ra to ry Records ORNL, RC13. F. R. Mynatt 27 . ORNL P a te n t O ff ice14 . R. T. San toro 28. EP§fMD R eports O f f ic e

EXTERNAL DISTRIBUTION

29. O f f ic e o f tbe A s s i s t a n t Manager f o r Energy Research and Development, DOE-ORO, Oak R idge, IN 37830.

30 . B. C hexal, E l e c t r i c Power R esearch I n s t i t u t e , 3412 H il lv ie w A ve.,P. 0 . Box 10412, P a lo A l to , CA 94303.

31 . S. Rosen, I n s t i t u t e o f N uc lea r Power O p e ra t io n s , 1820 Water P la c e , A t l a n t a , GA 30339.

3 2 . S. M. M irsky, B a l t im o re Gas ^ E l e c t r i c Company, P.O. Box 1475, B a l t im o re , MD 21203.

33 . C. D. F l e t c h e r , EG TG Idaho , I n c . , P.O. Box 1625, Idaho F a l l s ,ID 83415.

34 . C. B. D avis , EG TG Idaho , I n c . , P.O. Box 1625, Idaho F a l l s , ID 83415.35. L. P ed e rsen , P a c i f i c N orthw est L a b o ra to ry , B a t t e l l e B ld g . , R ich land ,

WA 99352.36 . B. Boyack, Los Alamos N a t io n a l L a b o ra to ry , P.O. Box 1663, Los Alamos,

MN 87545.3 7 . P. Saha, Brookhaven N a t io n a l L ab o ra to ry , Upton, NY 11973.38 . T. G. Theofanous, U n iv e r s i t y o f C a l i f o r n i a , Department of N uclear

and Chemical E n g in e e r in g , Santa B arb a ra , CA 93106.39 . R. O l iv e r , C o rpo ra te N uc lea r S a f e ty , C a ro l in a Power and L ig h t Co.,

F a y e t t v i l l e S t r e e t M all , R a le ig h , NC 27602.4 0 -4 1 . P. G u i l l , Duke Power Company, P .O . Box 33189, C h a r l o t t e , NC 28242.

42 . J . W. M in ar ick , Sc ience A p p l ic a t io n s I n t e r n a t i o n a l C o rp o ra t io n , Jackson P la z a Tower, 800 Oak Ridge T urnp ike , Oak R idge, TN 37830.

43 . R. O lson, Science A p p l ic a t io n s I n t e r n a t i o n a l C o rp o ra t io n ,Jackson P la z a Tower, 800 Oak Ridge T urnp ike , Oak Ridge, TN 37830.

U.S. N uc lea r R e g u la to ry Commission, W ashington, D.C.

44 . C. £ . Johnson4 5 . H. N ic o la r a s4 6 . J . N. Reyes47 . M. Vagins48 . R. H. Woods

20555;

49 -5 0 . T e c h n ic a l In fo rm a t io n C en ter

51-300 . Given d i s t r i b u t i o n as shomx in NRC C ategory RG, Systems and R e l i a b i l i t y R e p o r ts .

NOTICE

When you no lo n g e r need t h i s r e p o r t , p le a s e r e t u r n i t to D. L. S e lby , E n g in ee r in g P h y s ics and M athem atics D iv is io n , Bldg. 6025, MS 18W, Oak Ridge N a t io n a l L a b o ra to ry , P. 0 . Box X, Oak R idge , Tennessee 37831. Thank you.

i