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A REVIEW OF THE CURRENT STATUS OF NUCLEAR DATA FORMAJOR AND MINOR ISOTOPES OF THORIUM FUEL CYCLE

byS. Ganesan

Theoretical Physics Division

2000

BARC/2000/E/005

GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION

A REVIEW OF THE CURRENT STATUS OF NUCLEAR DATA FOR

MAJOR AND MINOR ISOTOPES OF THORIUM FUEL CYCLE

byS. Ganesan

Theoretical Physics Division

BHABHA ATOMIC RESEARCH CENTREMUMBAI, INDIA

2000

BARC/2000/E/005

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Technical Report

BARC/2000 /E/005

A review of the current status of nuclear data for major andminor isotopes of thorium fuel cycle

141 p., 104 figs., 2 tabs., 2 ills.

S. Ganesan

Theoretical Physics Division, Bhabha Atomic Research Centre,Mumbai

Bhabha Atomic Research Centre, Mumbai - 400 085

Theoretical Physics Division,BARC, Mumbai

Department of Atomic Energy

Government

Contd... (ii)-i-

BARC/2000/E/005

30 Date of submission : February 2000

31 Publication/Issue date: March 2000

40 Publisher/Distributor: Head, Library and Information Services Division,Bhabha Atomic Research Centre, Mumbai

42 Form of distribution : Hard copy

50 Language of text: English

51 Language of summary: English

52 No. of references: 49 refs.

53 Gives data on :

60 Abstract: In this paper, we present a critical overview of the status of the available nuclear data of isotopes of

thorium fiie] cycle, viz., 230Th, 232Th, "'Pa, 2MPa, 232U, 233U, and ̂ U. Included in the main body of the paper is a critical

analysis of information contained in the two basic evaluated nuclear data files JENDL-3.2 and ENDF/B-VI (Rev. 5)

recently released by the IAEA/NDS as a result of truly international efforts. In some of the cases, the information and

data given in EXFOR is examined to get an idea of the status of measured nuclear data of these isotopes. Some

comments regarding gaps in experimental data as of 1999 are included in the discussion. Most of these experimental

data were those generated two decades ago. In addition, generally, these experimental data are very limited in comparison

to the voluminous nuclear data generated for the uranium-plutonium cycle. Experimental data is absent in most of the

cases, and, in such cases, evaluated cross sections in the two basic evaluated nuclear data files JENDL-3.2 and

ENDF/B-VI (Rev. 5) are based upon theoretical models and nuclear systematics. Some of these differences between

JEF-2.2 and its source ENDF/B-V that were carried over to ENDF/B-VI (Rev.5) are explained. The role and the

importance of M' Pa and ̂ 'Pa in the thorium fuel cycle in advanced concepts such as the Energy Amplifier are mentioned.

New calculations of criticality property of "'Pa and "'Pa are presented using the neutron reaction data of JENDL-3.2

and ENDF/B-VI (Rev. 5). The possible influence of 230Th is examined with respect to its cross sections and production

of a i Pa in a typical Indian PHWR environment.The discrepancies in several neutron cross section data are illustrated

in the paper with a number of graphical inter-comparisons of JENDL-3.2 and ENDF/B-VI (Rev. 5) performed using

the PREPRO code system. The quality assurance in design and safety studies in nuclear energy in the next few

decades and centuries require new and improved data with high accuracy and energy resolution. The recent proposal

by CERN to use a high-resolution spallation driven facility at the CERN-PS to measure neutron cross sections in the

interval from 1 eV to 250 MeV deserves special mention. By such measurements, it is very likely that many new and

interesting results will come out. In addition, it is also useful to draw lessons from the international co-ordination

efforts that successfully created the FENDL file. There is a need to create a 'reactor FENDL' or a 'RENDL project'

that would achieve convergence of the various evaluated nuclear data files for reactor applications. As a starter, the

nuclear data of the set of isotopes of thorium fuel cycle discussed in this paper is a challenging sample for consideration

as a trial project.

70 Keywords/Descriptors : THORIUM CYCLE; THEORETICAL DATA; THORIUM 230;

THORIUM 232; PROTACTINIUM 231; PROTACTINIUM 233; URANIUM 232; URANIUM 233;

URANIUM 234; P CODES; VALIDATION; NEUTRON REACTIONS; NEUTRONS;

CROSS SECTIONS; PHWR TYPE REACTORS; REACTOR SAFETY

71 INIS Subject Category: S73

99 Supplementary elements:

-n-

A review of the current status of nuclear data for majorand minor isotopes of thorium fuel cycle.

ByS. Ganesan

AbstractIn this paper, we present a critical overview of the status of the available nuclear

data of isotopes of thorium fuel cycle, viz., 230Th, m T h , 23IPa, 233Pa, 232U, 233U, and 234U.Included in the main body of the paper is a critical analysis of information contained inthe two basic evaluated nuclear data files JENDL-3.2 and ENDF/B-VI (Rev. 5) recentlyreleased by the IAEA/NDS as a result of truly international efforts. In some of the cases,the information and data given in EXFOR is examined to get an idea of the status ofmeasured nuclear data of these isotopes. Some comments regarding gaps in experimentaldata as of 1999 are included in the discussion. Most of these experimental data werethose generated two decades ago. In addition, generally, these experimental data are verylimited in comparison to the voluminous nuclear data generated for the uranium-p-lutonium cycle. Experimental data is absent in most of the cases, and, in such cases,evaluated cross sections in the two basic evaluated nuclear data files JENDL-3.2 andENDF/B-VI (Rev. 5) are based upon theoretical models and nuclear systematics. Someof these differences between JEF-2.2 and its source ENDF/B-V that were carried over toENDF/B-VI (Rev.5) are explained. The role and the importance of 231Pa and 233Pa in thethorium fuel cycle in advanced concepts such as the Energy Amplifier are mentioned.New calculations of criticality property of 231Pa and 233Pa are presented using the neutronreaction data of JENDL-3.2 and ENDF/B-VI (Rev. 5). The possible influence of 230Th isexamined with respect to its cross sections and production of 23IPa in a typical IndianPHWR environment.

The discrepancies in several neutron cross section data are illustrated in the paperwith a number of graphical inter-comparisons of JENDL-3.2 and ENDF/B-VI (Rev. 5)performed using the PREPRO code system. The quality assurance in design and safetystudies in nuclear energy in the next few decades and centuries require new and improveddata with high accuracy and energy resolution. The recent proposal by CERN to use ahigh-resolution spallation driven facility at the CERN-PS to measure neutron crosssections in the interval from 1 eV to 250 MeV deserves special mention. By suchmeasurements, it is very likely that many new and interesting results will come out. Inaddition, it is also useful to draw lessons from the international co-ordination efforts thatsuccessfully created the FENDL file. There is a need to create a "reactor FENDL" or a"RENDL project" that would achieve convergence of the various evaluated nuclear datafiles for reactor applications. As a starter, the nuclear data of the set of isotopes ofthorium fuel cycle discussed in this paper is a challenging sample for consideration as atrial project.

A review of the current status of nuclear data for major andminor isotopes of thorium fuel cycle.

By

S. GanesanTheoretical Physics Division

Bhabha Atomic Research Centre,Mumbai - 400085,

India.Email at office: ganesan@magnum.barc.ernet.in

Email at home: s jmnesai»fl)vsnl.com

1. Introduction

India has considerable interest1 in developing thorium as a source of nuclearpower in the coming centuries. Using improved nuclear data and methods in simulationof nuclear systems is an important aspect of any serious nuclear program. The generationand use of accurate nuclear data are considered fundamentally important in any maturedprograms of nuclear energy, as accurate nuclear data are essential inputs to simulatephysics interactions to obtain engineering parameters. New concepts can be studied withgreater confidence if the scientific basis is sound.

Several Nuclear Reaction Data Centres co-operate2 in the creation and themaintenance of international databases of experimental and evaluated nuclear reactiondata for various incident particles such as neutrons, charged particles and photons. Thesenuclear data files have been under evolution in the last 40 years to satisfy the nuclear dataneeds in various fields of science and technology. Outstanding efforts by the nuclear datacommunity and by the nuclear data centres in the last four decades with their extremelylimited funding and resources have helped provide valuable nuclear data to the users allover the world. However, except for selected standard reference data, there is not yet one ,single universal nuclear data file with recommended best neutron cross section values.However all these libraries are in a single internationally recognized ENDF format3. TheEvaluated Nuclear data File version B (ENDF/B) format is being used throughout theworld by the nuclear data evaluators to define evaluated data. At the same time, ENDF/Bformatted files are used by the nuclear data users as a starting point from which evaluateddata is processed into the form in which it will be used in applications, e.g. multigroupcross sections in the 'MATXS' fonnat or continuous energy cross sections in 'ACompact ENDF/B' or 'ACE' format4. For the isotopes considered in this paper, the user(e.g., the author) has different nuclear data libraries originating from different countrieswith disagreeing numerical values. These are made available cost-free upon request bythe IAEA Nuclear Data Section (IAEA/NDS).

In this paper, we present a critical overview of the status of the available2 nucleardata of isotopes of thorium fuel cycle, viz., 2J0Th, 232Th, 23IPa, 233Pa, 232U, 2"U, and 234UNuclear data are available for all these seven isotopes in the three basic evaluated basic

data files: JENDL-3.25, ENDF/B-VI (Rev. 5)6 and JEF-2.27. The data of two isotopes,233U and 232Th are also provided in the Russian file BROND as well. The Joint Evaluateddata File7, JEF-2.2, for these isotopes has been essentially a carry-over from ENDF/Bdata, though some differences in the data of 232Th and 23 U are seen in comparison toENDF/B-VI (Rev. 5). Some of these differences between JEF-2.2 and its sourceENDF/B-V (which is carried over to ENDF/B-VI (Rev. 5) are explained separately inAppendix-A of the paper. Included in the main body of the paper is a critical analysis ofinformation contained in the two basic evaluated nuclear data files JENDL-3.2 andENDF/B-VI (Rev. 5) recently released5' 6 by the IAEA/NDS as a result of trulyinternational efforts.

2. General remarks on the status of nuclear data for the thorium fuel cycle

The quality of the basic data in the basic evaluated nuclear data files depend onthe amount and quality of the experimental information and, on the evaluation expertiseused in the evaluation. The availability of funding and the priorities in a country'sprogram generally influences the quality of the nuclear data. An attempt has also beenmade by the author to scan the information available in the experimental databaseEXFOR8 available on a CDROM, thanks to the IAEA/NDS. In some of the cases, theinformation and data given in EXFOR is examined to get an idea of the status ofmeasured nuclear data of isotopes of thorium fuel cycle, viz., 230Th, M2Th, ^'Pa, ^'Pa,

U, U, and HLJ. The author does not claim completeness of coverage of all theexperimental data for all the reaction channels. Note that the isotope 234U is common toboth the fuel cycles. Also the isotope236U which is relevant and plays a role similar to242Pu in the plutonium fuel cycle is not covered. Some comments regarding gaps inexperimental data as of 1999 are included in the discussion. Most of these experimentaldata were those generated two decades ago. In addition, generally, these experimentaldata are very limited in comparison to the voluminous nuclear data generated for theuranium-plutonium cycle. Experimental data is absent in most of the cases, and, in suchcases, evaluated cross sections in the two basic evaluated nuclear data files JENDL-3.2and ENDF/B-VI (Rev 5) are based upon theoretical models and nuclear systematics. Forinstance, retrieval and scan of EXFOR data reveals that there is no experimental data for(n, 2n) and (n, 3n) cross-sections for all the isotopes: 23OTh, 231Pa, 233Pa, 232U and 234U.One measurement in fission spectrum for (n, 2n) process 233U is found in the EXFOR andthe (n, 3n) cross section of 2 3U are based upon theoretical estimates. No experimentaldata exists for the inelastic cross sections except in a limited way for 232Th and 233U. Nodirect measurement of capture cross sections of 233U is available in the fast energy region.A relatively larger amount of measured data of fission cross sections of 234U and Thexist in the fast energy region relatively, though the knowledge above 6 MeV (needed foraccelerator coupled systems, for instance) is poor.

Seven years ago, a graphical inter-comparison of all the neutron reaction data ofJENDL-3 (Rev. 1) and ENDF/B-VI (Rev. 1) for all main isotopes of thorium fuel (230Th,232Th, 231Pa, 233Pa, 232U, 233U, and 234U) were made available in the handbook by Ganesanand MacLaughlin9.

In the present work, graphical inter-comparisons of all the neutron reaction data ofJENDL-3.2 and ENDF/B-VI (Rev. 5) were successfully performed using Red Cullen'sPREPRO code system10, LINEAR/RECENT/SIGMA1/GROUPIE, and over 200 graphsgenerated by the author of this paper are available separately11. Note that the generationof the cross section line shapes has been performed using the PREPRO code system witha specification of 0.1% in the LINEAR code and 0.1% in the RECENT code. Note thatthe input specification to the COMPLOT program has been made such that the ratio iscalculated with ENDF/B-VI (Rev. 5) in the denominator. The percentage discrepancy is(ratio-1) times 100. The inter-comparisons discussed in this paper give a generalimpression that the JENDL-3.2 is superior, with some exceptions, to ENDF/B-VI (Rev.5) for these isotopes. Generally, the Japanese data, JENDL-3.2, appears to be superior tothe author, for these isotopes, because the evaluations of nuclear data for these isotopeswere funded relatively better in Japan. As a result, generally, significant efforts weremade to incorporate the current status of theoretical predictions and availableexperiments in the creation of JENDL-3.2. On the other hand, as mentioned in thecomment section of the electronic file of ENDF/B-VI (Rev. 5) for these isotopes, theUSA database in ENDF/B-VI for these isotopes is essentially a carry over from theirearlier ENDF/B-V created around 1981.

It should be emphasized that any other team using any other processing codesystem such as the RECONR/BROADR/GROUPBE modules of the NJOY code system4

should arrive at essentially identical results in the inter-comparison graphs. Theinterested reader is encouraged to use the code system such as the NJOY code system forinstance to get inter-comparison graphs and verify that the results presented in this paperare essentially reproduced. This point is mentioned because the NJOY code isuniversally used for generating group constants and the author is using the PREPRO codesystem10 as a tool to get the discrepancies in the data. In the past, for instance, fairly anumber of quality assurance (QA) studies11"17 have been performed and processing codesimproved as a result of the IAEA cross-section code verification project a discussion ofwhich is outside the scope of this paper. The references11"17 are cited here to remind thereader that QA in nuclear data processing cannot be taken for granted as has beendemonstrated in the past.

A brief and interesting review paper by Kuzminov and Manokhin18 presents, fromthe point of view of nuclear data evaluators, an overview of an analysis of nuclear datafor. the thorium fuel cycle. The main conclusion of their study18 is that the existingnuclear database for the uranium-thorium fuel cycle is suitable only for preliminarydesign calculations.

3. Comparisons for 233U

The isotope ^ 'U is man-made. In the thorium fuel cycle it plays the importantrole of the main fissile fuel.

Ideally, the fission cross sections should be known in the energy region of interestto a very high accuracy, say, 0.5%. Generally, the fission cross sections of 235U and 239Pu

have been measured in very good experiments with a claimed accuracy of 2 to 3%.Except in the thermal region, the discrepancies seen in the case of 233U are very large.The uncertainty in the fission cross section data affects directly the uncertainty in thecalculated fission power, and influences criticality dimensions etc.

As illustrated in Fig. 1, the discrepancies between the JENDL-3.2 and theENDF/B-V1 (Rev. 5) in fission cross-sections at zero Kelvin for 233U range from -89.6 %to 1494 %. The comparison of fission cross sections of 233U, Doppler broadened totemperature of 296 Kelvin, shows differences of 88 % to 598% as illustrated in Fig. 2. Inthe 175 groups structure, the differences are -63 to +98% as demonstrated in Fig. 3.Presented in Fig. 4 are the discrepancies in the fission cross sections in the W1MS69group structure. As shown in Fig. 4, the 69 group fission cross sections are -4.735 to8.47% discrepant. Presented in Table 3 is a summary of discrepancies seen in Figs. 1-4in the comparisons of fission cross sections of U.

233 ,Table 1: Comparison of fission cross sections of U

DESCRIPTION

Zero Kelvin

296 K

175 groups

69 Groups

DISCREPANCY

-89.60 to 1495%

-88.44 to 597.9%

-63.34 to 97.35%.

4.735 to 8.470%.

REFERENCE

Fig. 1

Fig 2

Fig 3

Fig. 4

Table 1 should be viewed as an illustration. Such comparisons (for 0 K, 296 K,175 groups, 69 groups) or tables will not be repeated for each reaction and each nuclide.Note that as a result of significant "within-group" cancellation of discrepancies that arepresent in the positive and negative sides in Fig. 2, the discrepancies in the 69 broadgroups are now much smaller, in the range -4.735 to +8.470%. Generally, both theeffects of Doppler broadening and processing of the point cross sections into multi-groupvalues result in a reduction of the discrepancies observed in the cross section line shapesat the basic, zero Kelvin level. This is so in the resonance region unless a systematic biasis exhibited by the line shapes. It should be remembered that if there were a sharp, deltafunction like, mono-energetic neutron source at a given energy, the discrepancy at theconcerned point energy would dictate the discrepancy in the calculated reaction rate. Inthis sense, the sensitivity of an integral parameter in a specific design problem to aspecific cross section in a specific energy region will have to be calculated to conclude ifthe observed discrepancy is large enough to affect the integral results. Generally ourcomparisons will all be illustrated in the remainder of the paper at the zero Kelvin level.

With the general and specific remarks on the status of measurements on isotopesof the thorium fuel cycle, the significance of the large number of detailed inter-comparisons presented in this paper should be understood with proper perspective. If thecross section of two files completely agree with each other it does not necessarily meanthat there is no error in the data or that no further evaluations or validations throughintegral experiments are necessary. Under ideal conditions, the data in the two evaluateddata files may be considered to represent random samples from the infinite ensemble ofpossible evaluations. However, when the cross sections of two files agree with eachother, one should keep in mind the possibility of a systematic error that may make thetwo files differ from the true value by the some amount. An even more likelyexplanation of perfect agreement is that the data files are derived from a common(evaluated) data source. Improved differential measurements should be welcome toimprove the understanding of the differences in the cross sections in the two files andhelp eliminate them. More critical experiments to validate the cross sections are- highlydesirable in the case of the thorium cycle isotopes.

The magnitude of percentage differences for point cross sections and group crosssections presented in this report for various reactions should be interpreted andunderstood in proper perspective. The real significance of differences that are seen in thecomparison tables and the plots can be qualitatively appreciated with a proper perspectivewith regard to their possible impact on the application calculations. For instance, largedifferences of several tens of percent in the point cross sections in some cases can just bedue to slightly different resonance energies of sharp resonances in the two files.Similarly large differences will be seen in the plots of inter-comparisons if the thresholdenergies of a reaction, for example, the inelastic level excitation cross sections aredifferent in the two files. Many such differences essentially disappear when averaging isperformed over broad energy regions to obtain multi-group constants. The designersusing the multi-group approach, see multi-group cross sections such as those in Fig. 4 as"NUCLEAR DATA" which are input to reactor design codes to describe the basicneutron-nuclear interactions. Ideally, the fission cross sections, which directly dictate thecalculated fission power, should be known to a very high accuracy of one percent in theenergy region of interest. Note that the full set of multi-group constants used inapplications include4, in addition to the infinite dilution cross sections mentioned above,self-shielding factors in the resolved and the unresolved resonance region, Legendrecomponents of cross sections to account for anisotropy, inclusion of thermalizationeffects, neutron emission in fission, description of fission spectra etc.

Note the relatively good agreement at thermal energies in Figs. 1-4. Coming backto the Fig. 1, we find that the graph of inter-comparison covers several decades on alogarithmic scale on both the cross section and energy axis. The large differences in oneregion, due to the plotting scale, mask the proper exhibition of discrepancies in otherimportant regions. The only way to have an idea of the discrepancies clearly as afunction of energy is to zoom the Fig. 1 into several graphs for each of the smaller energyregions. This type of zoomed graphs comparing the fission cross sections of 231U havebeen generated and are presented in Fig. 5 (10'5 to 3 eV), Fig. 6 (3 - 5eV), Fig. 7 (5 to 60eV), Fig. 8 (60 - 150 eV), Fig. 9 (150 eV to 3.0 x 10*eV) and Fig. 10 (3.0 x 105 - 20

MeV). Large differences are strikingly seen in 60 to 150 eV energy in the comparisongraphs for U total, elastic, fission and capture cross sections as the resolved resonanceregion extends only up to 60 eV in the ENDF/B-VI (Rev 5) as compared to 150 eV in theJENDL-3 2 file

The unresolved resonance region for which average resonance parameters areprovided in ENDF/B-VI (Rev. 5) are 60-10 keV and 150 eV to 30 keV in the JENDL-3 2file. From the point of view of reactor physics, this essentially means that resonance self-shielding effects can be accounted up to an energy of 30 keV as a function of dilutioncross section and temperature using the JENDL-3.2 data as compared to 10 keV using theENDF/B-VI (Rev. 5).

A radiative capture process in 233U leads to a loss of a neutron. The (n, y) reactionleads to the formation of the 234U isotope, which is similar to the 240Pu isotope in the Pufuel cycle. Figs 11-20 present inter-comparison graphs for (n, y) cross section of 233U indetail. These graphs are specified in the same pattern as was shown for the fission crosssections in Figs. 1-10. The graphs are self-explanatory and the descriptions mentionedfor the fission cross sections similarly can be stated but will not be repeated to save

Til

space. A 600% discrepancy is seen for the capture cross section of U around 3 MeV asshown in Figs 11-13 and in the zoomed graph, Fig. 20. In the thermal region ( ~ 0.025eV) the discrepancy is about 1% as shown in Fig. 15 but increases to nearly 20% or morein the epithermal energy region at 0.8 eV (Fig. 16). The discrepancies in the resonanceregion (Fig. 17 and Fig. 18) are much larger. Figure 19 presents the inter-comparison inthe fast energy region, 150 eV to 300 keV. The small shift in resonance energies in thetwo files and the presence of additional resonances in the Japanese file in the energyregion under consideration lead to large discrepancies in the point cross sections that areshown in the inter-comparison graphs. This point is illustrated in the energy region 9 to16 eV by inter-comparison graphs presented in Figs. 21-24 for total, elastic, capture and,fission cross sections of 233U.

Figure 25 presents the inter-comparison graph for the total nubar of 233U, Fig. 26for the delayed nubar, Fig. 27 for the prompt nubar. A comparison of the total number ofneutrons released per fission shows that the files differ by -3.5 to + 3.7 %. The actualimpact of such differences depends on the neutron spectrum of the system underconsideration. The values of nubar in the thermal region (~ 0.025 eV) are relatively ingood agreement. The comparison for the total inelastic cross section is presented in Fig.28. The (n, 2n) cross sections of 233U are inter-compared in Fig. 29. This (n, 2n)reaction in 233U is one of the important routes for the formation of U, the daughters ofwhich are hard-gamma emitters. The evaluations of (n, 2n) reaction cross section of 233Uare based upon theoretical estimates. The EXFOR is found to contain one entry (No.20625) giving the measured value in a fission spectrum of average energy of 1.5 MeV as3.85 ± 0.45 mb. According to EXFOR8, it is based on the thesis work of T. Gryntakisperformed in March 1976 at the Technical University of Munich. The (n, 3n) crosssections of 233U are inter-compared in Fig. 30. The evaluations of (n, 3n) cross sectionsare based on theoretical estimates as a search in EXFOR indicated that no measurementsof this quantity have been made. Fig. 31 presents the inter-comparison of total cross

sections for the entire energy region (105 eV to 20 MeV) for the total cross section of233U. A zoom of Fig. 31, for the energy region 9-16 eV, has been given in Fig. 21 toillustrate the impact of slight shift in resonance energies in the two data files. Figure 32is again a zoom of Fig. 31 but in the fast energy region showing that the discrepancy iswithin -6.32 to +12.84 %. Ideally one would like to bring down the discrepancy close toachievable uncertainty in the state-of-art measurements of total cross sections. It isgenerally acknowledged that total cross sections can be measured to better than 1%accuracy in a good experiment.

4. Comparisons for 232Th

The main fertile isotope 232Th has an extensive experimental database of crosssections. However, the discrepancies between the evaluated data files are much larger ascompared to 238U, the equivalent and major fertile isotope in the uranium-plutonium fuelcycle.

Figures 33-53 present several inter-comparison graphs for the most importantfertile isotope 232Th of the thorium fuel cycle. As seen in Fig. 33, the thermal (n, y) crosssection are essentially in agreement. However, as we approach 5 eV, the (n, y) crosssection reconstructed at zero Kelvin using the JENDL-3.2 file is significantly lower thanthe ENDF/B-VI (Rev. 5) by over 37%. The capture process in thorium directly dictatesthe breeding of the 233U fuel. In some designs such as in the Molten Salt BreederReactor, the inaccuracy in the capture cross section of 232Th is not primarily a question ofbreeding feasibility since any inaccuracy in the capture cross section of 232Th can becompensated by a corresponding change in the concentration. In principle, it is possibleto arrange to capture all the neutrons that are available for breeding. Nevertheless aproper design of a reactor requires accurate capture cross sections of 232Th. The crosssection line shapes in the resonance region should be known accurately to predict the-Doppler reactivity effect. The cross section line shapes corresponding to the low energyresonances reconstructed using JENDL-3 2 and ENDF/B-VI (Rev. 5) produce differentline shapes as shown in Figs. 33-36 The differences are quite of concern as the effectivecapture reaction rates in some of the groups in the resolved region are discrepant by afactor of two. The discrepancies in Figs. 35 are in both directions arising from a slightshift in the resonance energies. For instance, the JENDL-3.2 file for 232Th has aresonance at 21.78 eV having a peak value of the capture cross section of 8529.666 barnswhere as in ENDF/B-VI (Rev. 5), the resonance is at 21.806 eV having a peak value of8444.237 barns. In Fig. 34 and Fig. 37, the area under the respective line shapes isinfluenced by the discrepancies in the line shapes, as there is not an effectivecancellation. In Fig. 34, a comparison of the capture cross section in the 5 -22 eV energyregion is presented. It is interesting to note that the resolved resonance region ends at 3.5keV in the JENDL-3.2 file but goes up to 4 keV in the ENDF/B-VI (Rev. 5) file as shownin Fig. 38. In Figs. 39 and 40, the fast energy regions are covered to illustrate that thediscrepancies are in the range of 10 to 15% in the capture cross section of 232Th. Above10 MeV, the discrepancies are strikingly large as illustrated in Fig. 40.

In Figs 41-43, the inter-comparison of total nubar, delayed nubar and promptnubar of 232Th are presented. In Fig. 44, presented is an inter-comparison for the fissioncross sections of 2 2Th. Except near the threshold, the fission cross sections are wellwithin a band of 5-10%. In view of the importance and the need to get a clear picture ofthe discrepancies, the graph of fission cross sections of 232Th presented in Fig. 44 weregenerated in zoomed form and presented in Figs. 45-50. Figure 51 presents an inter-comparison of inelastic cross sections for 232Th. The experimental database is sparse.Inter-comparison of (n, 2n) cross sections is shown in Fig. 52. Note that in 8 to 14 MeVenergy region, the agreement is within 10%. The formation of 232U is dominated by theroute 232Th (n, 2n) 231Th (pdecay) 231Pa(n, y) 232Pa (0-decay) 232U. The 232Th (n, 2n) crosssection data has a discrepancy of around 16% below 8 MeV and is 5 to 10% discrepant inthe 8-11 MeV region. Since this is a threshold reaction (6.34 MeV) more 2U isproduced as the spectrum is hardened. The production of 232U leads to problems due tohard gamma-rays emanating from its daughter products, in particular, 2l2Bi (gamma-raysof energy 0 4 to 2.1 MeV) and 2O8T1 (gamma-rays of 2.6 MeV). Inter-comparison of (n,3n) cross sections is shown in Fig. 53.

5. Comparisons of nuclear data for 231Pa

In this Section, we first briefly discuss the role and the importance of 231Pa in thethorium fuel cycle. Later in this Section, the inter-comparison graphs of cross sections of23lPa are discussed.

5.1 On the role and the importance of 231Pa in the thorium fuel cycle

The isotope 231Pa occurs in nature due to decay of 235U actinide (4n+3) series witha natural total world inventory of about 120 gm. In thorium fuelled reactors, productionof23 Pa takes place at several hundred grams per year per GWe of installed capacity19.The isotope 231Pa has a long half-life of 32760 +110 years for alpha activity. It isproduced primarily by fast neutrons through the (n, 2n) reaction on the main element32Th followed by beta decay. It constitutes a considerable source of radio-toxicity. In

advanced concepts such as the Energy Amplifier (EA) proposed by Carlo Rubbia20,production of 231Pa takes place in significant quantities and a net stockpile of the order of5 kg of 231Pa will persist during the whole life time of an EA plant.

Presented below are a few statements to understand the role of 23lPa in the long-term nuclear waste disposal of uranium-plutonium fuel cycle. It should be stressed that2JlPa does get produced over geological time scales in the uranium-plutonium fuel cycleas well. A detailed review was recently conducted21 under the Chairmanship of NormanJ. Rasmussen, Committee on separation Technology and Transmutation Systems. Basedupon this review an excellent book has been published by the National Research Councilof the USA. On p.386 of this book, (within quotes): "The depleted uranium tails canproduce a continuous source of radon if reasonable disposal methods are not employed.In the long run the main concerns are 226Ra, 210Pb (from the decay of 2'XU) and 3lPa, adaughter product of 235U." On Page 33 one finds (within quotes): "Calculations for agranite repository indicate that the main actinide contributor is not 237Np but rather 2JIPa

which grows in spent fiiel from the decay of its precursors ^'U, 239Pu, and 243Am. 23lPa islikely to be the radionuclide of significance for the dissolution and migration scenario ifthe long-lived fission products were greatly reduced. Long term build up of 231Pa in thedepleted uranium would continue as a significant source of environmental issue. In thetime scale of a few 100,000 years or larger, it could present more significant hazardsfrom surface or near surface dissolution and transport than is expected from the milltailings from producing new uranium fuel for LWRs." On p. 333 it is mentioned (withinquotes): "There would not be enough 231Pa in spent fuel to justify its transmutation, buttransmutation of its precursors U, 239Pu, and 243Am would remove the potentialproblem of 231Pa."

5.2 Results of inter-comparison of cross sections of " 'Pa

The nuclear data of 231Pa are inter-compared in Figs. 54-62. Figure 54 presentsthe inter-comparison of capture cross sections in the 10"5 eV to 20 MeV energy region.Fig. 55 and Fig. 56 are zoomed versions of Fig. 54 respectively for the lower and theupper energy regions. The capture cross section in the JENDL-3.2 file is a factor of twolower as shown in Fig. 56 in the 10 to 100 keV energy region of importance to fastreactors. Note that in the resolved resonance region, the evaluation in JENDL-3.2 followsthe 1981 data published by Abdel-Razik Z. Hussein et. al22., as compared to the use of1962 data of F. B. Simpson et al23., used in ENDF/B-VI (Rev. 5). The resolved resonacerange extends up to 115 eV in JENDL-3.2 file. The unresolved resonance parameters arespecified in the 115 eV to - 40 keV energy region in the JENDL-3.2 file. In ENDF/B-VI(Rev. 5) the unresolved resonance region covers the energy region 14.3 eV to 1 keV.These remarks confirm the general impression of the author that the nuclear data inJENDL-3.2 is in a sense superior to ENDF/B-VI (Rev. 5) for "'Pa, though this is not thesame impression for every reaction in every nuclide considered in this paper.

Significant differences in the 231Pa(n, f) in the two evaluated data files exist'though the absolute value of the 23lPa (n f) cross sections are small. An interestingmeasurement of fission cross sections of 3lPa in 0.1 eV to 10 keV has been reportedrecently by Prof. Katsuhei Kobayashi et al24., using a lead slowing down spectrometer atKyoto University, Japan. Such new measurements significantly help in improving thedata. The 2200 m/sec value is reported to be 25.0 ± 0.82 mb as compared to 19.66 mb inthe JENDL-3.2 file and 10.384 mb in the ENDF/B-VI (Rev. 5) file. The values of231Pa(n, f) in ENDF/B-VI (Rev. 5) in the 1 keV to 10 keV energy region are a factor of 20to 60 larger than in JENDL-3.2 file. The new experimental results of Kobayashi et al24.,are only about 3 times larger than the values in the JENDL-3.2 file. Figure 57 presentsan inter-comparison of fission cross sections of 231Pa. Fig. 58 presents the sameinformation as Fig. 57 but in 69 energy groups form. Incidentally, the normalization usedin Fig. 57 and Fig. 58 are different to show that while and if the reader would attempt toreproduce the COMPLOT runs presented in this paper, this factor should be taken intoaccount. Figs. 60-62 present the inter-comparison of total nubar, delayed nubar andprompt nubar respectively of ^ '

10

5.3 Comments on capture cross sections of 231Pa based upon the Russian integralexperiment.

A recent Russian study25 presents the following conclusion, based on comparisonof measured and calculated 2 2U production in thorium (within quotes; not edited): "Thecomparison of the calculation with the measurement results of uranium-232 content in theaccumulated fuel demonstrated a significant calculation overestimation. The mentioneddiscrepancy is connected with the inadequacy of capture reaction cross section atprotactinium-231 The present experiments demonstrates a necessity to decrease thatcross section by approximately 50%." Such experiments are highly desirable. In thiscase, at this time, it is not possible for the author to critically evaluate this statement asthe details of basic data, data processing to generate effective cross sections, spectrumcalculations, irradiation conditions, exact composition etc are not available in the paper.Compilation of such integral experiments in detail and analysis by independent teams arestrongly recommended

5.4. A new calculation of the criticality property of M1Pa.

The purpose of this section is to point out that there is a change in the assessmentof critical radius due to the use of improved input nuclear data of 23IPa in the calculationof criticality property of " 'Pa. In reference , (page 299, Table 2) provided are thecriticality data for bare fast assemblies of actinide nuclides. For H1Pa, a value of 162.31kg corresponding to a calculated critical radius of 13.61 cm (density= 15.37 g/cm3) ispresented 9.

Our calculations26 show that 231Pa can not be made critical. The infinite mediummultiplication factor is 0.9729 with the use of the latest basic neutron cross section data,JENDL-3.2. With this new data, our26 calculated kdj for a 13.61-cm sphere is 0.6029 forwhich the earlier study19 gave a value of unity.

Table 2: Summary of results of criticality property of z91Pa.

Description

keff of a sphere of radius of 13.61 cmusing Monte Carlo method (MCNP)

Infinite medium multiplication factor,k»

EarlierBARCStudy

1.000(DTF)

2.199(DTF)

Present Study(MCNP).based onJENDL-3.2.

0.6014 ±0.0034

0.9727 ±0.00114

The reason why 23TPa criticality studies are in error in Ref. 19 is not far to seek.The JENDL-3.2, which supercedes the JENDL-2 version, has been used in our study. OnP. 298 of reference19 it is stated that the data of 231Pa above 1 MeV was based on owncalculations of theoretical nuclear models and a complete file for 23IPa was assembledartificially by taking the data of 233Pa from JENDL-2 below 1 MeV. The use of the

11

JENDL-2 data, including nubar, of 233Pa below 1 MeV in constructing a complete datafile for 231Pa by merging model based data of 231Pa above 1 MeV is fundamentallyunacceptable. The ANSI critical mass value is 750 kg for 23IPa based on three-groupdiffusion theory calculation28. The assertion of the author is indeed limited to theconclusion that the value of 0.9727 obtained by processing the JENDL-3.2 file for k«, of231 Pa is a true reflection of the nuclear data contained in the JENDL-3.2 evaluation. Inother words, any other team in the world, starting from the JENDL-3.2 file should getessentially the same result. Recently Jung-Do Kim29 and Wienke30 found that theirindependently calculated values of lc*. for 231Pa using the JENDL-3.2 are essentially inagreement with our result. The ANSI value of the critical mass of 231Pa is not based uponany ENDF/B file. Use of ENDF/B-VI (Rev. 5) indicated26'30 a value of k« of 23IPa closeto 0.94. In other words, implicit is the conclusion that based on a future update, sayJENDL-4 or ENDF/B-VII in 10 years from now, based on improved differentialmeasurements, a k«, of slightly greater than unity may not ruled out. It is very unlikelythat the earlier published value that the k« was close to 2.199 for 231Pa could ever bereached by the uncertainties that we mention. Of course, a 5% uncertainty, for instance,in the calculated k«, arising from the uncertainties in capture and fission cross sections,nubar and fission spectra could take the present value of 0.97 to any where in the band of-0.92 to 1.02. One needs a measurement, of nu-bar, fission and capture cross sectionswith good accuracy in 0.1-3 MeV energy region.

6. Comparisons of nuclear data for 233Pa

In this Section, we first briefly discuss the role and the importance of 233Pa in thethorium fuel cycle. Later in this Section, the inter-comparison graphs of cross sections of233Pa are discussed.

6.1 Role and the importance of ^ P a in thorium fueled nuclear systems.

The role and the importance of 233Pa in emerging and advanced thorium fuelednuclear systems is briefly reviewed below to stress the relevance of this study.

The protactinium isotope, 233Pa, plays an important role as an intermediate isotopein the formation of the fuel 2 U in the thorium fuel cycle. A neutron capture in 232Thleads to 233Th which decays with a half-life of 22.3 + 0.1 minutes through beta emissionto 233Pa. The isotope a 3Pa decays with a half-life of 26.967 + 0.002 days leading to theformation of the nuclear fuel 233U. The isotope ^ P a is thus not a "long-lived" isotopebut its 27 days half-life requires careful attention in the design and operation of nuclearreactors using thorium fuel. The build-up and decay of M3Pa affect both the breeding andreactivity behavior. It is interesting to note that the equivalent of "protactinium effect" ofthe thorium fuel cycle is not of that much concern in the well studied 238U - M9Pu fuelcycle as the equivalent intermediate isotope 239Np has relatively a shorter, i.e., 2.3565 ±0.0004 days half-life.

12

Each capture in 233Pa not only causes a neutron to be lost, but also causes a 233Uatom to be lost as well (that is the 233U into which the 233Pa would have decayed). Thismechanism is proportional to the power level.

It may be noted that experience with experimental reactors using thorium in alarge scale is extremely limited in the world. A Light Water Breeder Reactor (LWBR) of90 MWe capacity was successfully demonstrated31 at Shippingport, Pennsylvania, USA.It operated for five years between from 1977 to 1982, using 501 kg of23 U inventory atthe beginning of life (BOL). According to Freeman et al31, p. 347, the experimentalobservations included measurements relating to the important role of 233Pa in a thoriumfueled reactor We quote: 'Time at zero power is important for a core with thorium fuelbecause 233Pa builds up to an equilibrium value while at power, and is reduced by decayto 233U with a half life of 27 days while at zero power. The decay of 233Pa removes aneutron absorber from the core and increases the fissile content; both reactivity andbreeding performance are affected. While near 100% power, ~ 2% 231Pa was lost byneutron absorption in the LWBR. The reactivity worth of 233Pa was measured to be 2.45± 0.10% Ap at -11000 Effective Full Power Hours The worth depends on core agebecause of the competition from fission products and changing worth of U comingfrom the 233Pa. Calculations have indicated that for the LWBR, about two-thirds of the233Pa reactivity effect was due to 233Pa absorption, and about one-third was due to the233U produced. Since 233Pa is primarily an epithermal absorber, the relatively hard fluxspectrum tended to increase its absorption rate."

In the case of Fast Breeder Reactors employing thorium, the transient reactivityeffects arising due to the "protactinium effect" should be carefully evaluated and takeninto account in design and operation. The first one month of operation will see a fall inreactivity due to build up of 233Pa and its delayed (27 days half-life) decay to 233IJ Thereactivity effect of 233Pa is less if thorium is used only in the blanket region, as leactivityworth is lower in the periphery as compared to the central region.

To appreciate the role played by 233Pa in the Energy Amplifier concept of CarloRubbia32 it is interesting to take note of some numbers. According to the calculationsperformed by Carlo Rubbia et al., (page. 211 of Reference32), the ratio of number ofatoms of 233Pa to that of 233U in the 600 MWe fast energy amplifier has an equilibriumvalue of 0.0208. The breeding gain due to premature capture in 233Pa is reduced by0.00480. The criticality rise after 10 days shut down due to the decay of 233Pa into 233U is+0.00413. The criticality rise after infinite shut down due to the decay of 233Pa is+0.0203. The operation and safety considerations of thorium fueled reactors shouldadequately take into account the neutronic characteristics of Pa. The significance ofthe magnitude of the reactivity numbers can be appreciated by noting that typically forthorium systems the effective delayed neutron fraction is about 0.003 which means that acritical reactor would go prompt critical on the addition of a reactivity of about 0.003.

The role of 233Pa will depend on tHe history and the flux level of the acceleratorcoupled sub-critical reactor system. In one design32, the flux level is low enough (--2 x10* ) to be dominated by "decay" where the rate of neutron captures by 233Pa competing

13

with natural decay is kept negligible In the other design, the high flux ( ~1016) leads to a"capture dominated" regime studied by Bowman et al3., where the 233Pa formed shouldbe removed as quickly as possible to avoid capture. To save space, the interested reader

1 1 1 1

may consult the references ' for more details.

Interestingly, the m P a isotope has raised34 some weapon-proliferation concerns aswell. Generally, it has been assumed that the thorium fuel cycle is proliferation resistantwith the formation of the 232 U whose daughter products after five successive alpha daysare hard-gamma emitters. The isotope 23 U, formed by (n, 2n) reactions in 2 2Th and233U leads to hard-gamma emitting daughter products and thus makes 233U handlingextremely difficult. In a recent study by Bowman34 on the Accelerator DrivenTransmutation Technology (ADTT) Project, it is mentioned that, in theory, a sizable (11kg) fraction of the estimated inventory of 22 kg of 233Pa could be extracted from themolten salt blanket of thorium, using heroic measures, to produce pure weapon grade213U. In the ADTT concept, (page. 149, Reference34) it is interesting to note (withinquotes): "With the removal of 11 kg of 233Pa, the thermal power level would havedecreased by a factor of three and the net electric power into the commercial grid by afactor of about five while the accelerator power would have remained the same. Thepower level would recover over a period of several months but the inconsistency betweenthe accelerator power and the electric power output would be readily observed byinfrared mapping from satellites or by other means".

The reactivity effect 233Pa on the shut-down margin has also been calculated byPelloni, Youinou and Wydler35 for a model used in the "Accelerator Driven Systems(ADS) neutronic benchmark calculations" carried out in the framework of the IAEA Co-ordinated Research Programme entitled: "On the use of thorium based fuel cycles in ADSto incinerate plutonium and to reduce long-term waste toxities". It was found35 that theEnd-Of-Life (EOL) "Pa effect" is 1495 pern with the use of JEF-2.2 file and 1674 pem,with the use of JENDL-3.2. In the latter case, the EOL "Pa effect" is thus 1% too highand a global reactivity adjustment of 1% by means of a change in the core geometry isindicated" as a result of the use of nuclear data in JENDL-3.2 for 233Pa.

6.2 Inter-comparison of cross sections of "'Pa

Presented in Fig. 63 and Fig. 64 are the inter-comparisons of fission cross sectionsof 233Pa: It is seen that the values of fission cross sections in JENDL-3.2 are a factor oftwo lower than in the ENDF/B-VI (Rev. 5) in the 2-6 MeV energy region. In Figs. 65-70, presented are the inter-comparisons of capture cross sections of 23 Pa. As shown inFig. 66, the agreement in the thermal and the low energy region is within -4.29 to +5.07%. For 233Pa, the resolved resonance region extends up to 16.5 eV in JENDL-3.2 ascompared to 17 eV in ENDF/B-VI (Rev. 5). The upper limit of the unresolved resonanceregion is 40 keV in JENDL-3.2 and is 10 keV in ENDF/B-VI (Rev. 5). Fig. 67 illustratesthe discrepancies in the resolved resonance range that is up to 16. 5 eV in the JENDL-3 2file and 38.5 eV in the ENDF/B-V1 (Rev. 5) file. The unresolved resonance range covers38.5 to 10 keV in the ENDF/B-VI (Rev. 5) file and 16.5 eV to 40 keV in the JENDL-3.2file. Seen in Fig. 68 is a discontinuity while joining the end of unresolved resonance

14

region to smooth cross sections above 10 keV in the case of ENDF/B-VI (Rev. 5). In thecase of 233Pa there is only one measurement of fission cross section in a fission spectrum.The capture data is based on theoretical estimates. Each capture in 233Pa not only causesa neutron to be lost, but also causes a 233U atom to be lost as well (that is the 233U intowhich the 233Pa would have decayed). This mechanism is proportional to the powerlevel. As illustrated in Fig. 69, the capture cross section in JENDL-3.2 is larger by afactor of over 2.5 in the 100-700 keV energy region. The values of total nubar arecompared in Fig. 71 which illustrates that the JENDL-3.2 evaluation is about five percentlower than the values in the ENDF/B-VI (Rev. 5) file in the lower energy region below 4MeV. Fig. 72 shows that the (n, 2n) cross sections of 233Pa are 2.7 times larger in theJENDL-3.2 file. The (n, 3n) cross sections of 233Pa are 20-30 % discrepant except nearthe threshold as shown in Fig. 73.

6.3 Use of new nuclear data in the calculation of criticality property of 233Pa.

Calculations performed in collaboration with H. Wienke36 shows that the qualityassurance (QA) in nuclear data and in processing can not be taken for granted. A valueof ketrof 0.85 was mentioned by late Prof. PA. Landeyro37, Italy for a 23 Pa sphere with aradius of 17.72 cm, in his letter dated 15 Dec. 1995 on the basis of the use of "ENDL-85", asking the opinion of the author. The drastically different revision of the infinitemedium multiplication factor, k«r of the ANS result27 (-0.5) to 1.811 for M3Pa by anearlier report3 based on JENDL-2 in 1990 is not substantiated by our improved andrigorous investigations36 based on JENDL-3.2. Our improved processing and analysisemploying the NJOY97.95 and the MCNP-4B codes and using the JENDL-2 dataresulted36 in a value for k«, of 1.45172 ± 0.00146 which differs from the earlier value of1.811 showing QA problems in nuclear data processing in the earlier38 study. Thepresent calculations performed by Wienke and the author36 give a k« = 0.36853 ±0.00063 with the use of JENDL-3.2, and a value of 0.46033 ± 0.00111 with the use ofENDF/B-VI (Rev. 5). Complete details and analysis of this investigation including theuse of other available files such as JEF-2.2 will be published elsewhere36.

7. Comparisons of nuclear data for 234U

The 234U isotope formed by neutron capture in 233U. It decays by alpha emissionwith a half-life of 2.4 105 years. In thorium reactors, the formation of 235U by neutroncapture in 234U helps to reduce the burnup swing in long life cores. Since 234U also getsformed by (n, 2n) reactions in 235U, the 234U isotope is common to both uranium andthorium fuel cycles. The 234U isotope plays a role in thorium fuel cycle similar to the240Pu isotope in the Pu fuel cycle. The 23 U isotope plays a role in thorium fuel cyclesimilar to the role played by the isotope 241Pu in the Pu fuel cycle. The isotope 236U notcovered in this report corresponds to 2Pu.

7.1 Inter-comparison of cross sections for 234U

Presented are the inter-comparison graphs for the isotope 234U in Figs. 74-91. Asseen in Fig. 74, the values of capture cross sections at the thermal energy in ENDF/B-VI

15

(Rev. 5) is 3.2% larger than in JENDL-3.2. In the resonance region and beyond, till 1MeV (Figs. 75-79), the capture cross sections in ENDF/B-VI (Rev. 5) are larger generallyby about 15-20% Around 3 MeV, the opposite trend is seen (Fig. 80). In Fig. 81depicting the inter-comparison of capture cross sections of 234U in the 10-20 MeV energyregion, the values differ by factors of several hundreds.

One of the interesting discrepancies is that seen in Fig. 82 for the value of thermalfission cross section of 234U in the JENDL-3.2 file. Note that the value of fission crosssection (6.22 mb) at the thermal energy in the JENDL-3.2 is ~ 75 times smaller than thevalue in the ENDF/B-VI (Rev. 5) file. A recent measurement by C. Wagemans et al.,yielded39 for the thermal fission cross section of 234U, a value of (300 ± 20) mb. Thisvalue in ENDF/B-VI (Rev. 5) is closer (464 mb), showing that the value of the thermalfission cross section of 234U in the JENDL-3.2 is rather too small

In both the data files, the resolved resonance region extends up to 1.5 keV but theunresolved resonance region extends up to 100 keV in ENDF/B-VI (Rev. 5) as comparedto 50 keV in JENDL-3.2 The energy region 2 eV to 1 MeV is covered in Figs. 83-86,which are self-explanatory. In the 1-10 MeV region, the fission cross sections are withina band of -4.6 to +3.8% as illustrated in Fig. 87. In Figs. 89-91 the prompt nubar,delayed nubar and the total nubar parameters of 234U are inter-compared. The smalldiscrepancy in total nubar of 234U between the two data files is impressive.

8. Comparisons of nuclear data for 232U

The formation of 232U in the thorium fuel system mainly takes place by thefollowing reactions: 233U(n, 2n) 232U, 232Th(n, 2n) 231Th (P decay) 231Pa(n, y) 232Pa (pdecay) 2 2U. The isotope 232U has daughter products that are strong gamma emittersThe fabrication of 233U fuel having more than a few ppm of 23 U require remotefabrication and handling. The presence of considerable amount of 232U is viewed asproviding increased security and non-proliferation. Similar to 238Pu of the plutonium fuelcycle, the isotope 232U is characterized, as pointed by Gennady et al,40 by intense heatgeneration caused by radioactive decay (Tin — 68.9 ± 0.4 years) and has a specific heatgeneration of 740 Watts per kg without accounting for the contribution to the decay heatfrom the daughter isotopes. Besides hard gamma radiation, the intense heat removalmust be provided40 for in handling 233U fuel with significant fraction of 232U. Accordingto an estimate by Zaristskaya et al l, the maximal exposure dose rate at 1 m distance from1 mg 232U point source in equilibrium state with its daughter products is equal to12.9mR/h. For amount of 1 kg of 232U, the dose rate exceeds 10000 R/h. Such dose rateprovides an effective protection of the fuel. The study by Gennady et al.,40 employing532^23ipa/^y M ^ e x o t i c feed ^ j w J t h p e r c e n t a g e s o f 232u and «»pa exceeding 30%

or more is theoretically interesting. Such conceptual studies obviously need betternuclear data for the isotopes 232U and 231Pa in order to have a sound scientific basis.

16

8.1 Inter-comparison of cross sections for U

As shown in Fig. 92, the discrepancy in prompt nubar of 232U is significant. TheJENDL-3.2 file has a prompt nubar value of 2.456 based on systematics. This is 21.6%lower than the value given in the ENDF/B-VI (Rev. 5), 3.126, that is based upon the onlyone measurement of the quantity reported by J A. Farrell42 It is recognized by theENDF/B evaluators-A comment to this effect has been recorded in the electronic file-that this value obtained in the measurement is larger than the value obtainable from theuse of systematics. In special conceptual studies where 232U criticality is analyzed, thisdiscrepancy will have a significant impact on the results of calculations. Othercomparison graphs are presented in Figs 93-97. Fig. 93 provides an inter-comparison ofdelayed nubar parameter, Fig. 94 those of fission cross sections, Fig. 95 those of capture,Fig. 96 that of (n, 2n) and Fig. 97 that of (n, 3n). As seen in Fig. 96, the (n, 2n) crosssections of 232U are low in JENDL-3.2 by an order of magnitude in comparison to thevalues based on systematics generally for the actinides. In Fig. 95, it is clearlydemonstrated that the line shapes of the capture cross sections in the 1 keV to 20 MeVenergy region are in disagreement. As seen in Fig. 97, the (n, 3n) cross sections of 232Uare 10 to 30 times discrepant.

9. Comparisons of nuclear data for 230Th

Figures 98-104 present inter-comparison graphs for ""Th. Fig. 98 inter-comparesthe capture cross section of 230Th in the entire energy region. There are large differencesin the resonance cross sections and the line shapes of the capture cross sections in theMeV energy region are in disagreement. As illustrated in Fig. 99, the thermal capturecross section is 6% larger in the ENDF/B-VI (Rev. 5) file but about a factor of twosmaller as we go through the first resonance. The inter-comparison of capture crosssections of 230Th in 100 eV to 2 keV energy region presented in Fig. 100 illustrates thatthe resonance regions are having different limits in the two files. The JENDL-3.2 hasresonances described in terms of multi-level Breit Wigner resonance formalism up to564.26 based upon the measurements of Kalebin et al43. The resolved resonance region isdescribed by Single Level Breit Wigner parameters adopted from the "barn book" BNL-325 and extends up to 251 eV in ENDF/B-VI (Rev. 5). In the resonance reconstiuctedcross section data file, scattering cross sections are unphysical negative values in someenergy regions in the ENDF/B-VI (Rev. 5) file. This is explained in some detail inAppendix-A. In Fig. 101 the fission cross sections of 230Th are inter-compared. In theregion 1-20 MeV, the discrepancies are seen to be within a band of -35% to +44% asseen in the zoomed plot shown in Fig. 102. In Fig. 103, a comparison of (n, 2n) crosssections are presented showing good agreement between the two files. Both evaluationsuse an evaporation model. The comparisons in Fig. 104 illustrate the presence of adiscrepancy of a factor of 3 in the (n, 3n) cross section.

17

9.1 Calculations of Production of M1Pa arising from "°Th

In the case of thorium fuel, only the 232Th isotope is considered to be naturallypresent and assumed to be 100% abundant. However, it has been stated in the literaturethat the isotopic composition of thorium ores varies considerably, depending on theamount of associated uranium and its effect in producing an admixture of 230Th daughter.A survey by P. E Figgins and H. W. Kirby44, indicated that the ionium content ofthorium ores can vary from almost zero up to as much as 11.6%.

Some general remarks are made taking the numerical values of cross sections for230Th. The 2 Th isotope, if present in thorium fuel pins, will go to 23ITh by neutroncapture. The 231Th has a beta half-life of 25.52 ± 0.01 hrs leading to the formation of23lPa which is a source of high radiotoxity with a half-life of 32760 + 110 years and isthus a real long-term radioactive waste. The ^'Pa is considered as a serious radioactivewaste. One may have to isotopically purify thorium to remove 230Th before putting it forirradiation in a nuclear reactor. Also as far as design studies of thorium reactors areconcerned, in a thorium fueled thermal reactor, the 230Th isotope will compete with 232Thin capturing neutrons. The numerical values for 23OTh isotope recommended by theJENDL-3.2 file are used to make the following remarks. At thermal energies, the neutroncapture cross section is 22.5 barns which is about 3 times that of 232Th that has a capturecross section at 2200 meter/sec velocity of the neutron, a value of 7.4. barns. Theresonance integral of 230Th is 1040 barns which is 12 times that of W2Th which has acapture resonance integral of 84.4 barns. Thus 230Th captures by an order of magnitudemore in the resonance region in comparison to 232Th. In the fast energy region 23 Th hasabout twice the fission cross section of 232Th. For instance, the fission spectrum averagedneutron induced fission cross section is 163.1 millibarns as compared to 78.48 millibarnsfor 232Th. This fact represents indirectly a positive bonus for increasing slightly thepower of the reactor coming from thorium in the fast energy region and also helps inbreeding 233U fuel by contributing to increase of fission source neutrons that may beultimately captured in 232Th to breed 233U.

It is of interest to estimate the possible influence of the 230Th isotope if thisisotope is present. The formation of 23lPa by neutron absoiption in 230Th in a typicalIndian PHWR spectrum, for instance, is discussed in reference45. Corresponding to0.025% by weight of 232Th of loading of 400 kg in KAPP-1, i.e. per 0.1 kg of 2™Thpresent, the amount of 231Pa produced in 300 days turns out to be about 4.6 gm This isfor an assumed total flux of l.OE+14 in the thorium region and a density of 9 gm/cc ofthorium. The details are presented in Appendix B.

10. Concluding remarks

The quality assurance in design and safety studies in nuclear energy in the nextfew decades and centuries require new and improved data with high accuracy and energyresolution. The recent proposal by Carlo Rubbia46'47 to use a high-resolution spallationdriven facility at the CERN-PS to measure neutron cross sections in the interval from 1eV to 250 MeV deserves special mention. Their scheme proposes to use the CERN

18

facility that is expected to provide 3 orders more fluxes of neutrons or 1000 times smallertargets for equivalent neutron induced reaction rates. New experimental measurements ofneutron cross sections for isotopes of thorium fuel cycle will help resolve the existingdiscrepancies between JENDL-3.2 and ENDF/B-VI (Rev. 5). By such measurements, itis very likely that many new and interesting results will come out.

It is useful to draw lessons from the international co-ordination efforts thatsuccessfully created the FENDL file. FENDL stands for Fusion Evaluated nuclear datafile2' 48 '49 By a series of QA studies, integral benchmarking, improved measurements,analysis and improved nuclear model based calculations, the best of the availableevaluated data files were assembled for isotopes and elements of interest to fusion reactorapplications under this project The FENDL project of the IAEA had a comprehensiveapproach including QA assured nuclear data processing that lead to the production ofworking libraries for integral validation studies. There is a need to create a "reactorFENDL" or a "RENDL project" that would achieve convergence of the various evaluatednuclear data files for reactor applications. As a starter, the nuclear data of the set ofisotopes of thorium fuel cycle discussed in this paper is a suitable sample forconsideration as a trial project.

References

1. See the articles in the web-site of Bhabha Atomic Research Centre at: http://www-barc^rnetin

2. For more details, visit the web-site of the IAEA-NDS at: httpV/vv wvwids iaea org

3. ENDF-102 "Data Formats and Procedures for the Evaluated Nuclear Data FileENDF-6", Cross Section Evaluation Working Group, February 1997, BNL-NCS-44945, Rev.2/97, Brookhaven National Laboratory.

4. R. E. MacFarlane, 'The NJOY Nuclear Data Processing Code System, Version 91,LA-12740-M (1994). This code is referred to only for the purpose of reference to thereader on formats of "MATXS" and "ACE". Note that the linearization, resonancereconstruction and Doppler broadening calculations presented in this paper were allperformed using the PREPRO code system cited in Ref. 10 below.

5. "JENDL-3.2, The Japanese Evaluated Nuclear data Library by the JAERI Nucleardata Centre and the Japanese Nuclear Data Committee," Summary of Contents, H. D.Lemmel (Editor), IAEA-NDS-110, IAEA Nuclear Data Section, Vienna, Austria,Europe. Data obtained on CDROM from the IAEA Nuclear Data Section, 1999.

6. P.F. Rose (Editor), "ENDF/B-VI Summary Documentation," Report BNL-NCS-17541 (ENDF-201), Brookhaven National laboratory 1991, Data Library ENDF/B-VI, Rev. 5, Update 1998, Data obtained on CDROM from the IAEA Nuclear DataSection, 1999.

19

7. JEF2.2, CDROM IAEA-NDS-CD-04, data obtained on CDROM from the IAEANuclear Data Section, 1999

8. EXFOR, database of experimental nuclear reaction cross sections, Version January1999, Data obtained on CDROM from the IAEA Nuclear Data Section, 1999

9. S. Ganesan and P. K. MacLaughlin, "Status of Thorium Cycle Nuclear DataEvaluations: Comparison of Cross Section Line Shapes of JENDL-3 and ENDF/B-VIFiles for 230Th, 232Th, 23IPa, 233Pa, 232U, 233U, and "4U," Report INDC (NDS)-256,(1992) Nuclear Data Section, International Atomic Energy Agency, Vienna, Austria.

10. Dermott E. Cullen, "PREPRO96: ENDF/B Pre-processing Codes," University ofCalifornia, Lawrence Livermore National Laboratory, IAEA-NDS-39, obtained fromthe IAEA Nuclear Data Section (1996)

11. D. E. Cullen, "Verification of the Nuclear Cross Section Processing Codes,"INDC(NDS)-134, IAEA Nuclear Data Section, Vienna, Austria, 1982.

12. D. E. Cullen, "The Accuracy of Processed Nuclear Data," Nucl. Sci. Engg., 99, 172-181 (1988).

13. S. Ganesan, V. Gopalakrishnan, M. M. Ramanadhan and D. E. Cullen, "Verificationof the Accuracy of Doppler Broadened, Self-Shielded Multigroup Cross Sections forFast Power Reactor Applications," Annals of Nucl Energy, 15, pp.113-140 (1988).

14. S. Ganesan and D.W. Muir, "IAEA Activities in Nuclear Data Processing forThermal, Fast and Fusion Reactor Applications using the NJOY System," pp. 145-170, in Proceedings of the OECD / NEA Seminar on NJOY-91 and THEMIS,OECD/NEA Data Bank, Saclay, 7- 9 April 1992 (1994), OECD, Paris.

15. S.Ganesan, V. Gopalakrishnan and M. M. Ramanadhan, "Problems and Experiencesin Nuclear Data Processing in Developing Countries" Progress in Nuclear Energy, 14,pp. 301-311 (1984)

16. Papers presented in the NJOY user Group Meetings 1992-1995, Contact person. E.Sartori, NEA Data Bank, and Paris. The details are given in the NEA web-site:hitp;//wwwjieaifr

17. S. Ganesan, "Experiences in processing of basic evaluated nuclear data files:Linearization, Resonance Reconstruction, Doppler Broadening and Cross SectionAveraging," p. 568-588, in Proceedings of the Workshop "NUCLEAR REACTIONDATA AND NUCLEAR REACTORS, Physics, Design and safety," ICTP, Trieste,Italy, 15 April-17 May 1996, World Scientific Publishing Company (1998)

18. B D. Kuzminov and V. N. Manokhin, "Analysis of Nuclear Data for the ThoriumFuel Cycle," p. 1167-1171, CONFERENCE PROCEEDINGS, Volume 59, Part II,

20

Internationa! Conference on Nuclear data for Science and Technology, Edited by G.Reffo, A. Ventura and C. Giandi, Italian Physical Society, Bologna, Italy (1997).

19. M Srinivasan, K. Subba Rao, S. B. Garg and G. V. Acharya, "Systematics ofcriticality properties of special actinide nuclides deduced through the Trombaycriticality formula," Nucl. Sci. and Eng., 102, 295-309 (1989).

20. C. Rubbia, S. Buono, Y. Kadi and J. A. Rubio, "Fast Neutron Incineration in theEnergy Amplifier as Alternative to Geologic Storage: The Case of Spain" " ReportNo. CERN/LHC/97-01 (EET), February 17, 1997.

21. Committee on Separation Technology and Transmutation Systems, Book publishedby the National Research Council of the USA (1996).

22. Abdel-Razik Z. Hussein et. al., Nucl. Sci. Eng., 78, pp. 370-376 (1981). The JENDL-3.2 evaluation uses this resonance data for 231Pa.

23. F. B. Simpson et al., Nucl. Sci. Eng., 12r pp.243-249 (1962). The ENDF/B-VI (Rev.5) evaluation uses this resonance data for 3 Pa.

24. K. Kobayashi, "Measurements of Neutron-Induced Fission Cross Section ofProtactinium-231 from 0.1 eV to 10 keV with Lead Slowing-down Spectrometer andat 0.0253 eV with Thermal Neutron facility," J. Nucl. Sci. Tech. 36, 549 (1999)

25. A. V. Zvonarev et al.,"The Research of Thorium Samples Irradiated in the FastNeutron Reactor Radial Blanket and in the Graphite Type Reactor ThermalSpectrum," presented at the 1998 "RUSSIAN-INDIAN WORKSHOP ONTHORIUM FUEL." (1998)

26. S. Ganesan, Umashankari, P. D. Krishnani, V. Jagannathan, R. P. Jain and R.Karthikeyan. "A Re-calculation of Criticality Property of 23lPa Using New Nuclear 'Data," Current Science, Vol. 77, No. 5, pp. 667-670, 10 Sep. 1999, Indian Academyof Sciences, Bangalore.

27. AMERICAN NUCLEAR SOCIETY, "Nuclear Criticality Control of SpecialActinide Elements," An American National Standard, Report ANSI/ANS-8.15-1981(1982).

28. George C. Wu and Lawrence Ruby, "Possible Criticality of Protactinium-231,"Nuclear Science and Engineering, 68,349-368 (1978)

29. Jung-Do KIM, Private communication (1999).

30. H. Wienke, Private communication (1999)

21

31. L. B. Freemnan et al., "Physics Experiments and Lifetime Performance of the LightWater Breeder Reactor," Nucl. Sci Eng. 102, 341-364 (1989)

32. C. Rubbia et al., "CERN-GROUP Conceptual Design of a fast Neutron operated HighPower Energy Amplifier" Section D 3, pp. 187-312, in Report IAEA-TECDOC-985,ACCELERATOR DRIVEN SYSTEMS: ENERGY GENERATION ANDTRANSMUTATION OF NUCLEAR WASTE, Status Report, November 1997,International Atomic Energy agency, Vienna, Austria, Europe.

33. C. Bowman et al., Nucl. Inst. Methods A320, 336 (1992).

34 C. Bowman, "Basis and Objectives of the Los Alamos Accelerator DrivenTransmutation Technology Project" Section D. 2.1, pp. 135-153, in Report cited inRef.6 above.

35. S. Pelloni, G. Youinou and P. Wydler "Impact of different nuclear data on theperformance of fast spectrum systems based on the thorium-uranium fuel cycle,"p. 1172-1176 in CONFERENCE PROCEEDINGS, Vol. 59, PART II, InternationalConference on Nuclear data for Science and Technology, Edited by G. Reffo, A.Ventura and C. Grandi, Trieste 19-24 May 1997, Italian Physical Society, Bologna,Italy (1997)

36. S. Ganesan and H. Wienke, "On the criticality property of 233Pa derived from variousnuclear data files using the NJOY and the MCNP codes (Under preparation)

37. Prof. PA Landeyro, Italy, Letter dated 15 Dec. 1995 and addressed to S. Ganesan

38. S. B Garg, "Criticality Configuration Studies Using Pa-231, Pa-233, U-233 and \J-234 Actinides", p. 117-118 in T. K. Basu and M. Srinivasan (Editors) in THORIUMFUEL CYCLE DEVELOPMENT ACTIVITIES IN INDIA (A Decade of Progress1981-1990) Report B ARC-1532, Bhabha Atomic Research Centre, (1990).

39. C Wagemans et al., Nucl. Sci. Eng. 132, 308 (1999)

40. K. Gennady et al., "Equilibrium Th-U Fuel Cycle of LWRs with elements ofProtection Against Fissile materials Proliferation," p. 331-335, Volume 1,Proceedings of the International Conference on The Physics of Nuclear Science andTechnology, Oct. 5-8, 1998, Islandia Mariott Long Island, New York.

41. T. S. Zaristskaya et al., Atomnaya Energia, 48, No. 2, 67-70 (1980)

42. J. A. Farrell, Report: LA-4420 (1970)

43. Kalebin et al., Soviet Atomic Energy 26, 588 (1969).

22

44. P. E Figgtns and H. W. Kirby "A survey of sources of ionium (Thorium-230),"USAEC report MLM-1349, Oct. 1966

45. S. Ganesan, V. Jagannathan, P. D. Krishnani and DC. Sahni, "Estimation ofproduction of 23lPa from 230Th in PHWRs," Unpublished (1998)

46. C. Rubbia et al., "A High Resolution Spallation Driven facility at the CERN-PS toMeasure Neutron Cross sections in the Interval from 1 eV to 250 MeV " Report No.CERN/LHC/98-02 (EET), May 30, 1998

47. C. Rubbia et al., "A High Resolution Spallation Driven facility at the CERN-PS toMeasure Neutron Cross sections in the Interval from 1 eV to 250 MeV: A RelativePerformance Assessment" Report No. CERN/LHC/98-02 (EET)- Add-1, June 15,1998

48. A. B. Pashchenko, H. Wienke and S. Ganesan, "FENDL: International referencenuclear data library for fusion applications," Journal of Nuclear Materials 233-237(1996) and references cited there.

49. A. B Pashchenko, H. Wienke and D. W. Muir, B FENDL-2 An improved nuclear datalibrary for fusion applications," p. 1150-1154, CONFERENCE PROCEEDINGS,Volume 59, Part II, International Conference on Nuclear data for Science andTechnology, Edited by G. Reffo, A. Ventura and C. Grandi, Italian Physical Society,Bologna, Italy (1997).

Acknowledgement:

The author gratefully acknowledges with thanks the encouragement and keen interestshown in this work by Dr. A. Kakodkar, Director, BARC, Dr. S. S. Kapoor, Director,Physics Group and Dr. D. C. Sahni, Head, Th. P. D., BARC. Fruitful professionalinteractions in terms of nuclear data services with members of the IAEA Nuclear DataSection are gratefully acknowledged. The author sincerely thanks his colleagues DC.Sahni, V. Jagannathan, P. D. Krishnani, R. P. Jain, Umasankari Kannan, R. Karthikeyan,and Usha Pal for many fruitful discussions.

MAT 8228 rianlonCRMB Section

02-0-233-BB.BO To 1406. %

10*

§ 10°10°

10I 1 0

O I BTOP/fe-ri (fel . B) B-233

o10

,0°

0 C JSNDL-3.8 0-233/0 C BBF/&-7I (Bel. S) U-233 j

105 103 1 10* O6105 10* 103 1 ^ 10* 10° 101 10? 103 10* 105 tO6 107

Iocidrat Energy («T) « -U -233

Fig. 1: Comparison of resonance-reconstructed point fission cross-sectionsof 233U at zero Kelvin temperature. This plot has been derived from JENDL-3.2 and ENDF/B-VI (Rev. 5) using the LINEAR/RECENT/COMPLGTcodes of the PREPRO system. A reconstruction tolerance of 0.1 was used inLINEAR and in RECENT. Note that the large discrepancies -89.60 to1495% seen in 60 to 150 eV energy regions are easily explained by the factthat the resolved resonance range extends up to 150 eV in JENDL-3.2 ascompared to only 60 eV in ENDF/B-VI (Rev. 5). However this masks theexhibition of discrepancies in other regions where the discrepancies appearillusively low. Zoomed portions of this plot are therefore presented in Figs. 6t o l l .

24

MAT 8222

3

10*

10°

10*

102

10°

ID1

10°

101

BHJF/B-VI (HOT. 6) 296 I

FissionCram Ssction

WHJ -233-88.44 He 887 8 X

i•«•»! i . I . I < ^ i M I I H ) i • i i i«j i '1 ' iy ) i ' i ' i « [ i I H | I >

JBfBL-3.3 (CDHOi) 2B6 K

4 H < H < I • • • • N ' I \ ' • > " » < • • • • ' « <

JHTOL-3.2 208 VfflDF/B-VI (BOT. fi) 206 K

io^ i ? iff5 IO1 iou IO1 lor 10 10 10 ioB 10

Incident Energy (e7) 92-D -233

Fig. 2: This figure inter-compares the point fission cross sections of 2J3U at296 degree Kelvin. These curves were obtained by Doppler broadening thezero Kelvin cross section line shapes of Fig. 1 using the SIGMA1 code.Note that, as compared to Fig. 1, the effect of Doppler broadening results inreducing the values of fission cross section at the resonance peaks andincreasing the values at the wings of the resonances. The spread ofdiscrepancy between the two data files JENDL-3.2 and ENDF/B-VI.5 forthe fission cross section of 233U is thus reduced to -88.44 to 597.9% ascompared to the value of 89.6 to 1494% seen in Fig. 1 at zero Kelvin.

25

MAT9E22 FlSBlObCrow Sectiao

-233-€3.34 To 97.35 X

f rf

«.o°

10

101

10°

2.0

i"" 1.0

0.5

lwplwi

M i *

Omwlwl

Mlo

296 E D-233 EHV/B-VI 5 175 6

»•'>«!' «>-i»H i

l

396 K D-233 JHOJL^.2 175 G

I • M'»|—I >Mi|'|—t

D-233 JQiDL^.S 175 G/2flfi K U-233 Bflff/B-VI.5 ITS C

-jUjhi

** to io° IO 1 itr io3 io4 to5 to6 io7

Incident Energy («T) 92-0 -233

Fig. 3: The "point" fission cross sections at 296 K were multi-grouped usingthe GROUPIE code of the PREPRO system into 175 values in the TART 175group energy structure. Note that as result of some cancellation ofdiscrepancies that are seen in the positive and negative sides in Fig. 2, thediscrepancies in the 175 broad groups are now -63.34 to 97.35%.

26

HAT 8322 fissionCrass Section

82-0-333-4.735 To B.470 S

Z96KU-Z33 EMff/H-VI.5

I . ) • ! • > ) i i l i l i l ^ I i l i l ' H I . I « t » y |

80S i D-333 jnmir3.a I

E V-833 ENDF/B-VI.5

* 1Q1 4 10° * 101 * 10Z * rf * 10* + 105 * 108 4

Incident laecgj (eT) 9S-U -233

Fig. 4: The "point" fission cross sections at 296 K were multi-grouped usingthe GROUPIE code of the PREPRO system into 69 values in the WIMS69group energy structure. Note that as result of significant "within-group"cancellation of discrepancies that are seen in the positive and negative sidesin Fig. 2, the discrepancies in the 69 broad groups are now in the range4.735 to 8.470%. Note the good agreement at thermal energies.

27

MAT 9222

10

I03

o

I •°.o3

1.02

8ICO

FlsslocCross Section

-233-0 523 To 1.452 5

Km

0 E HIDF/B-VI (Hel. 5} P-Z33

0 E JiNDL-3.2 I> 233/0 I ENEP/B-71 (Rel. S) U-233

Incident Energy («?) 9S-C-233

Fig. 5: Comparison of resonance-reconstructed point fission cross-sectionsof U at zero Kelvin temperature. Fig. 1 zoomed using the COMPLOTcode of the PREPRO system to show the discrepancies in 10~5 to 0.3 eVenergy region.

28

MAT8E2 PinionGran Section

92-U-233-14.90 To 39 3B 2

0 I HIW/B-f 1 (Bel. 5) 0-233

0 I JIMDL-3.S 0-233

0 I JHDL-3.2 0-233/0 E BTOF/&-7I (Rel. S) 0-233

'-I' I

Fig. 6: Companson of resonance-reconstructed point fission cross-sectionsof 233U at zero Kelvin temperature. Fig. 1 was zoomed to show thediscrepancies in 0.3 - 5 eV energy region.

29

MAT 92-D -233-78.39 To Zfb.fi

FlSfllOBCross Section

0 I HTOT/B-VI {Re]. 5) U-233

0 I JIiDL-3.2 U-233

0 E JBfflL-3.2 U-233/0 K ENDT/&-VI (Rel. ft) U-233

Incident Energy

Fig. 7: Comparison of resonance-reconstructed point fission cross-sectionsof U at zero Kelvin temperature. Fig. 1 was zoomed to show thediscrepancies in 5 - 60 eV energy regions. Note that the resolved resonancerange extends up to only 60 eV in ENDF/B-VI.5.

30

MAT 8 3 2

10

i 10

S *to

10

10

10°

10

60

FissionCross Section

9B-U-233-B9.GD To 1496. %

Iwi

fetteUsfctla.

0 K Efflff/B-?! (Bel. 5) D-233

| .e| i l i j ' l i I i t • > • I ' I ' I ' I ' I • I •> • >• I • M l • I I H • I »t

Q K JIHDL-3.& IHS31

mill:

0 E JEHDL-3.S D ^ / 0 E EMTf/B-VI (Rel. 5) D-S33

100 120 140

(«Y)

Fig. 8: Comparison of resonance-reconstructed point fission cross-sectionsof 233U at zero Kelvin temperature. Fig. 1 was zoomed to show thediscrepancies in 60-150 eV energy region. Note that the large discrepanciesin point cross sections are due to the fact that the ENDF/B-VI (Rev. 5) endsits resolved resonance range at 60 eV.

31

MAT9EK2 FiasionCrews Seotic

93-0-233-14.68 To 24.88 %

0 K Hng/B-VI (Rel. 5) 0-833 |

I - I • < ) > • > < I ' M - I ' | • 1

0 I JXMDL-3.Z D-233

0 I JBTOL-3.2 D-233/0 t Bflg/ft-7I (Rel. S) D-233

iff toIncident Energy («7) 93-0-233

Fig. 9: Comparison of resonance-reconstructed point fission cross-sectionsof 233U at zero Kelvin temperature. Fig. I was zoomed to show thediscrepancies in 150eV to 300 keV energy regions. The unresolvedresonance region covers 150 eV to 30 keV in JENDL-3.2 and 60 eV to 10keV in ENDF/B-VI (Rev. 5).

32

MAT 032

n

1.00

FissionCross Scctioo

92-0 -233-l.flTB To 10.75 S

0 I HUff/B-VI (Rel. S) P-Z33 |

0 I JEfflJL-3.2 U-233

0-233/0 K ENET/B-7I (Rel. S) U-233

Incident Energy (e?) «0-U-233

Fig. 10: Comparison of fission cross-sections of 233U at zero Kelvintemperature. Fig. 1 was zoomed in the 300 keV - 20 MeV energy region toillustrate that the discrepancies are from -1.876% to +10.75%.

33

MAT 8 8 2 (n.7)Cross Section

92-0-2337749. 5

KEHDP/&-VI (Sel . 5) tf-333

il !..,.J I ...i.J I.J..J .....J .....J

10* 10" 10 10 10 10 10

Incident Energy (eV) 98-0 -833

Fig. 11: Comparison of resonance-reconstructed point capture cross-sectionsof 233U at zero Kelvin temperature. Zoomed portions of this plot arepresented in Figs. 15 to 20.

34

HATBB2

10

10

10

ID1

o 10

Croaa Section

296 I SfUF/fr-YI (Sel. 5) D-Z33

Mlfj >-Ht»| I ' l l * ) Hl»l»t I 'UN

286 E JENDL-3.2 U-233

Sttl K IENDL-a.2 U-^33/206 K HTDr/R-Vl (Bel 5} U-233

i i

10* * Iff1 ' i f rf' 10°Incident Energy (e7) -233

Fig. 12:Inter-comparison of the Doppler broadened point capture crosssections of 233U at 296 degree Kelvin.

35

MAT 8222 fn.7)Cross Soction

86-9-233-lOO.OOIb SB4.0

296 K U-233 HKff/B-YI.6 175 G

2QSKP-333 JBfflL-3.a ITS G j

175 0/286 K g-833 iMff>B-Vl .5 ITS 6 [

iocideai Energy («Y)

Fig. 13: The "point" capture cross sections at 296 K were multi-grouped using theGROUPIE code of the PREPRO system into 175 values in the TART175 group energystructure.

MAT a s s (n.r)Croas Seotlcn

9&-UH333-4».61 Tb 906.3

296 K D-233 EKff/B-YI .5

104 10" 10* 10Z It? * 10* * iO5 106 107

Incident Energy 92-U -233

Fig. 14: Inter-comparison of the capture cross sections at 296 K in 69 groups in theWIMS69 group energy structure.

37

MAT 9222

k

t

5 «

1.04

1.00

Cross Section -2.6B3DTO 4.635 5

Ha

0 S HRF/B-VI (8el. 5) 0-233

i)—i t • i inimmiii)—i—i • i • i miitumf—• i • i n.nm'in^—• > • t •lO'imMil

0 E JHJD1-3.Z tt-233

| • i . < in>mniii| i t i i • i I I I H I I I » ( — • i • t iiiniiti<i4<|—» t » i '

0 1 JEHDL-3.2 1^233/0 E Effif/B-VI (Rel. 5) U-233

run1

104

Incidrat Energy («V) 92HJ-233

Fig. 15: Note that the discrepancy in the thennal region (0.025eV) is around2%.

MAT 8222

if?

to1

t

1.4

1.3

1.0

OB

Crun SeotiOB92-U-233

-84.860% 8B.94 K

J o K Hmr/B-vi (nei. s) g-aaa

o i JEffli-a.g p-gqyo K EMEP/B-VI (a«i. s) o-saa |

Incident Energy («T) «2-U -833

Fig. 16: This plot illustrates the discrepancies in the energy region, just above the thermalenergies for the (n,y) cross sections of M3U. These energy regions are important in tightlattice reactors.

39

1AT8222 0>.r)Cross SoctiQB aw .7 %

a 10o

I10

10

olmi

0 I g » / a - Y I (ttol. B) D-233

'•I »!•«»

0 I JEMDL-3 Z D-233

I I|II»IIIII|IIIIIIII|I»II»I

0 E JSMDL-3.2 D-233/0 K EO'/B-VI (Rel. S)

Incident

KM.

• I >•

-233

Fig. 17: Inter-comparison of capture cross section of 233U in the resolvedresonance region, 5 to 60 eV.

40

MAT 9222Cross SBOUQB

93-0-233-B0.63ITO 7749. 3

I-110

10

.rf*

•o1

Mi*lit

OKHfU/B-VI (Bel 6} 0-233

« i • i • i » | • i • i • t • i • i • i • i • i > i » | • i • t • i • i • > » i • t • i • i • | • i • i « t • i •

0 I JENBL-3.2 &-233/0 C EMV/fr-71 (Rel. 5) 0 233

Fig. 18: Inter-comparison of capture cross section of 233U in the resolvedresonance region for JENDL-3.2, 60 to 150 eV.

41

MAT 822 (n.7)Cross Sactian

92-0-33317 .SB X

!

1

10*

0

4?0.8

ViaMlo

{- Q E BCT/a-TI (fttl- S)

0 I JSSEL-3.2 U-233/0 E BffiP/B-VI (Bel, 5) P-233»-+

i a i B i 'a 1 1 . k i 4 t l I «iflT

Incident Energy («V) -233

Fig. 19: Inter-comparison of capture cross section of 233U in the energyregion, 2 to 300 keV.

42

MAT 9222

10

I ifG0

• 10°

\ *

IB2

04J

10*

(n.r)Craes Section

92-5-2336M.9 z

o i s) n-233 {

. ! « • • • • • <

0 I JXHDL-3.2 U-233

• i . •••i....i....i~..t...i».

0 £ JSffiL^.2 U-233/0 E MW/&-VI (Rel. 5j U-233

10

Incident Energy

Fig. 20: Inter-comparison of capture cross section of 233U in the energyregion, 5 to 60 eV.

43

MAT 9£22 TotalCram Section

92-fl -233-49.B2 To 66.82 X

i A

01}

2.0

1.6

1-2

o.e

beBatlo

0 I raw/B-VI {Bel. 5) D-SS30 E JENEL-3.2 0-333

| I I « I » > I I I ) I I I I I I I I I [ I I 1 I M I I I [ I I I I I I t I I | I I I I > I M ) [ I I I I i I I I I | I I I M H M •}

0 I JSNDL-3.8 U-S33/0 K EHDF/B-YI (Rel. 6) tt-233

10 11 IS 13

Incident Energy (

14 15 16

9B-D -233

Fig. 21: Comparison of total cross sections of 233U in 9~16eVenergy region.

44

MAT 9222 ElasticCross Section

93-D -233-Z7.ZQ To 5.313 %

I130

ie3 14

" 12

O 10

8

1.1

0 1.0

i °-B

OB

LBibl«

0 t BnV/B-7I (Re] 5} U-Z330 E JMDL-^.2 U-233

| I I I I I I I t I { I M »• I » I I I \ ) I I I I t I I I | I I I I I I I I I | I I M I I I I I I I I I I I I I I I I I I I M I I > I \

0 I JSHDL^.3 ^233/0 K EHDP/&-7I (Rel. S) 0-233

in 11 is 13 u is LG

Incident Energy (eY) 0B-U -239

Fig. 22: Comparison of elastic cross sections of 233U in 9-16eVenergy region.

45

MAT 9322 Flaslo*Cross Section

-233-53.66 To 59.15 %

10

i

101

l.B

1.8

0.8

0.4

tariwd

ktlo

0 I EHDr/O-VI (Rel. 5) 0-2330 E JBtDL-3.2 D-233

,| I I > I I II I I | H I I M ) I I | I I I I I t I I I | I I I I I t I H | I I I I I M I I I I I I I I M I I | I I I t I I I I I |

0 1 JHDL-3.8 &-233/0 K BTOF/B-?! (Rel. S) U-833

LQ LI \Z 13 14 15 16

Incident Energf (e?) 92-0 -233

Fig. 23: Comparison of fission cross sections of 233U in 9-16eVenergy region.

46

MAT 8322 (n.r)Cress Section

93-0 -£33-4B.E3 To H» 9 5

00

10'

3.0

2.0

1.0

Miafctla

0 I BTOF/&-YI {Re]. 5) D-E330 1 JBDDL-a.2 3

11111 1111 1111 M M 111) 1111 !• M 11 11111 11111111 i H i i 111 111111 n i 111 n 11 i i 1

\ 0 I JBiDL-a.8 P-833/0 K EHOP/B-FI (Rel. 5) U-g33

/

LQ 11 1 2 1 3

Incident Energy («?)

14 IS IB

-233

Fig. 24: This comparison illustrates that the discrepancies arise dueto slightly different peak energies of the resonances and presenceof additional small resonances in the JENDL-3.2 file.

47

MAT 9222 Total 9

1

0

I

5.5

90

4.0

3.5

3.0

2.6

1.0*

1.00

OSS

hilt

HOT/B-TI (Bel. 5) D-233JHBL-a.2 0-333

92-0-233-4.2TO 1b a.SBG %

fcttol

in • i • i • i • n | inm n m m i - m <t«i u • ••>•! n • i • i

JiHDL-a.2 D-S33/ KNDf/B-YI (Bel. S) U-233

10 15

Incident (M)

80

-233

Fig. 25: Comparison of "total nubar," the total number of neutrons emittedin fission as a function of incident energy of the neutron.

48

BAT 822 Delayed vParameter

OHI-233-90.77 to 10.64 2

J

0

i

fetln

ER1F/B-7I {Rel. 5) D-233JSSDL-3.2 D-233

IEKDL-3.2 D-233/ EHDF/B-YI (Rel. S) U-233

Incident Energy (Me?)

SQ

9B-II-Z33

Fig. 26: Comparison of "delayed nubar," the number of delayed neutronsemitted in fission as a function of incident energy of the neutron.

49

5.0

4.6

4.0

3.5

3.0

2.5

1 fU

1 f»

0 96

HAT 9 3 2

'

*

•

BW/B-VlJ5MDL-a.2

• H f H | i | i | ' l i

J2JDL-3.2

0-233

1 » > • 1 H

D-S33/

ProqitVParameter

anMl*

5) D-233

| ' i i i n

ENDF/B-VI (Bal .

^ ^

. . . . . . i . . . . . . . .

92-D-Z33-3.S70 IV) 3.740 %

•in

-

•

n i ii m 11 • i ii. 11 n i . f i ' i • 1.1

9) 0-233 |

10 IS

(fc?)

SO

92-5-233

Fig. 27: Comparison of "prompt nubar," the number of prompt neutronsemitted in fission as a function of incident energy of the neutron.

50

MAT 8622 InelasticCroes Sactitn

83-D -233-30.01 To 6&.M. X

K

i •0 -1

o IO1

0

I

Ifi8

1.6

1.2

0 8

KBLMto kilo

0 K HOT/B-VI (Bel 5) D-Z33 TTireahold 4O.5ED keV0 1 JBffiL-3.2 D-«33 Ansbold 40.575 I ?

0 E JEK&L-a.e D-233/0 I EMDP/B-7I (Rel. 5) U-233

TTttt10

-|—* - i i a - v r J10

Incideat Energy -233

Fig. 28: Comparison of the first inelastic level excitation cross section. Notethat the threshold energies specified in the two files are slightly different.

51

HAT 9222 «HJ -233-69.B? To 460.2 %

10

KiaLMLI*

0 I HTOF/B-VI (Rel. &) H-233 Threshold 5.7BB9 KeVQ E JBiDL-a.S VS3B ^reabold 5.7786 fcV

0 C JBfDL-3.8 U-233/0 E IHEf/B-VI (Rel. fl) D-233

Incident Energy (MeT)

Fig 29: Comparison of (n, 2n) cross sections.

52

MAT 9222Cram Section

W-0-233-34.88 TO 18.17 %

.010

iio1

0

I04

to8

1.2

0.8

0.4

HiaJKIo M i a

0 E HTOT/B-VI {Rel. 5) B-233 Tbreahold 13.066 Me?0 K JMDL-3.2 U-J233 *Rireshold 13.066 MeV

0 E JEHB1.-3 E U-233/0 K tm/BhVl (Re!. P) 0-233

13 14 IS 16 17 IB 19 20

Incident Energy (Me?) 9HJ -233

Fig 30: There are no measurements on (n, 3n) cross sections forU. The curves are based on theoretical estimates.

53

mms

10

03-0 -233-72.77 To 1634. S

BJDT/B- VI (Rel S) U-Z33JBBBL-3.2 D-233

0 I J i m 3.8 D 3̂33/0 I ggy/B-YI (Bel. S) P-233]

-4 ? _V4 - * _|~4~ „ 4 | T - 4 * 4 4"T s~T~ R T 7

io* ior iff5 IO1 io° IO1 ior JO3 10* ioa ioB io7

Incident Energy («?) «2S7 -233

Fig . 3 1 : The inter-comparison of total cross sections of 233U in the 10"5 eV to 20 MeVenergy shows a spread of -1211 to + 1634%. The different resolved ranges in the twofiles lead to the large discrepancies in the inter-comparison. See the comparison in Fig.32 for a zoom of the energy region above 150 eV.

54

HAT 8222

ao

J

TotalCross Section.

KHH233-6.315 1b 12.84 X

04*

45

40

35

3D

25

Z0

15

10

5

1.1

1.0

Mid t

ftwwlwi

LM1«__L

0 I Bnv/S-TI (Rel. 5) B-2330 I JIHDL-3.2 D-233

0 E JISSL-3.2 U-233/0 E ENCP/&-7I (Rel. S) B-233

it i'i'i\ ii'i'fVio5 ioB

Iocident Energy «g-fl-Z33

Fig. 32: The inter-comparison of total cross sections of U in the 150 eV to20 MeV energy shows a spread of-6.315 to + 12.84%.

55

MAT 8040

10

(n.y)Crises Section

0 K HTW/B-VI {Bel. 5)Th-23Z0 S IENDL-3.2 Tb-23S

«>-Th-232-37 BB To O.CES 2

•in

— • i • i.i.in'H»i—• i 11 I IUHIM

0 I ISSDL-a.Z lh-238/O K

B 7 r, £ 6 B ? ,10 - =

Incident Energy (c7)

10"

90-Tli-232

Fig. 33: Inter-comparison of capture cross sections of 232Th in the thermal and lowenergy regions.

56

HAT 9040

10

id"

ID1

8.0o

•—H

(n.r)Crass Section

W-TIl-232-64.Bl To U2.0 X

l ia

0 K HTW/B-YI (Re]. 5)Tb-2320 E JEfflL-3.2 Tb-233

I i • I • • • •

0 I JEMDL-3.8 Th-238/D I EHPF/fr-VI (Bel. S)Th-83g |

6 6 10 12 14 16 IB 20

Incident Energy («Y) W-TIr-232

Fig. 34: Inter-comparison of capture cross sections of 232Th in the 5 to 22 eV energyregion to illustrated that the resonance cross sections are discrepant by over a factorof two.

57

MAT 9040 (n.y)Crews Section -BO.46 To S05.2

lrtto•ia

Lfctt*

0 K ESW/B-VI {Rel. 5)Th~Z3zl0 E JENDL-3.2 fh-838 J

10

102

10

10

[ • » • ! i | • ! i t i l i | i t H • | • > • • » > » I - t i » • « » i | - I i l i l i | i t i | i n | i | i ! < ! < ! • l l > • | i l - n | < t i H H H I H « t » t • ! •

0 I JEMDL-a.2 Th-g3a/0 K SNDP/B-VI (Bel.

22.0 ZZ.5 Z3.0

Incident Energy (e?)

235 Z4.U

90-TIr-232

Fig. 35: Inter-comparison of capture cross sections of Th in the 21.5 to 24 eVenergy regions to illustrate that the resonance cross sections are discrepant because ofa slight shift in the resonance energies. The peak values do not agree.

58

HAT 8040 (n.r)Cross Section

9CH1HS38-96 SO To 4646. 5

I'"3w *

Q 10

10

to1

0 I01

to1

ftot Ilia

Q I EHIV/B-TI (Rel. 5)TIh-23S0 t JEJDL-̂ 3.2 Th-233

0 E JENBL-3.2 1^238/0 K EMSF/B-VI (Bel. 6)Th-23&

•232nFig. 36: Inter-comparison of capture cross sections of Th in the 25-100 eV energyregion.

59

i? $ 11 it i if

MAT 55040 (ii.r)Cran Station

10

]5 ID?

§ to1

10I

o i mv/B-vi (Bel. 5)Th-aae0 E JBDL-a.2 Tb-B33

I, • • i i l i n i H n . t m . l )

-ioa.ocm>

Bstla•til

0 I JH0>L-a.8 thr8aa/Q K EHDF/B-VI (Bel. 5)Tt-83g

10

Incident EnergF

Fig. 37: Inter-comparison of capture cross sections of 232Th in the 100 eV to 3.5 keVenergy regions to illustrate that the resonance cross sections in the JENDL-3.2 fileare clearly lower on the average.

MT 8040

!>o'

010

to

u

163

Mi*

VM7)CRIBS SuuLian

HFm-232-B9.77Cnb 375.5 3

0 I HOT/B-7I {Bel. 5)Ti-2320 I JBiDL-3.2 e&

-*-8—» t » I » I « | I i » I » ) • I • ( < I I I « I • t • | • I I I >• » I « i

0 E J2NDL-3.S fh-232/0 K ENDF/B-VI (Bel. 5)11-332

Rfff3.6 3.8

Incident Energj

4.0

W-Tlr-232

Fig. 38: Inter-comparison of capture cross sections of 232Th in the 3.5-4.0 keV energyregion to illustrate that the resolved region in ENDF/B-VI (Rev. 5) extends up to 4keV. In the JENDL-3.2 file the average cross sections are obtained treating thisregion as unresolved.

61

MAT 9040 (n.r)Cross Section

«J-T_-Z32-13.760TO 2B1 0 X

•?io°

o

la1

T36w

Mia

feramlwdi i a

0 E HQF/B-VI {Rel. 5)T_-23Z0 K JSNDL-a.2 Tit-ZX

OK JEMBL-3.2 Ik-23S/0 E

fAy*1"^—*—*rr*

(Hel. 5)11i-232

10 io5

Incident Energj («Y)

tr 10

W-Tbt-238

• 232-Fig. 39: Inter-comparison of capture cross sections of Th in the 4 keV to 3 MeVenergy region

62

BAT 9040Section -300.00TO 15.00 X

1.2

0.4

0.0

0 Z WW/B-VI (Rel. 5)Th-Z3Z0 I JSNDL-3.2 Rj-233

Jitto

I » I » I • I • H I • > • I» I » I I I 4 | . | I I t | I | \ | I | • 1 I | H • | i ni«i 4t i in . i l t. i.l.i .1 n m

0 I JBTOL-3.8 R-33a/0 i EHDF/6-VI (Bel. 5)7*1-332 |

B 10 12 14

Incident Energy (Mrf)

16 IB m

flO-Th-232

Fig. 40: Inter-comparison of (n, y) cross sections of 232Th in the 3.5 to 20 MeVenergy regions.

63

MAT 9040 Totel 9nuraeter

90-T1H332-1.733 1b 64.79 3

6.5

6.0

4.5

J < • <3.5

3.0

£.5

2.0

i.e

12

IGm

HfW/tt-71 (Rel. S) D-233J1HDL-3.2 U-233 Thnshold 400.00 keT

. \

. t . i • i . i • i • i • t • t • i • ( • » > t • 111 • t « t • i « i » i • | » i • t> i • i » i • i • i • > •< • ) • i » < . i . > •« • i • t • i • i

| jsroL-a.e nsa3/ Bny/B-vi (Bel, S)

5 10 IB

Incident EEBTOT (Msf) 90-T1HZ32

232nFig. 4]: Inter-comparison of total nubar of Th

64

Delayed 9Fteraaeber

90 T-1O.91 TO 0.798 X

fe&laSia

BTDT/B-?! (Rsil. ft) 0-S33JiMDL-3.8 D-£33 Ibresbold 400.00 IBB?

43

) = I • t .̂ t • 1 • ) ' C • I < I • ) • I • I • I ' I • 0 ' I • I • • : 1 • j i ) • I ' I • I • I • I • I • I • I • f ' I • t • I • I ' I • 4 - H

jaa>L-a.a a)s.oo

0-86

to

Enwrgy (JfaY)

IB SO

S0-Tlr-Z32

232-1Fig. 42: Inter-comparison of delayed nubar of Th

65

I

ft.O

4.6

4.0

3.S

3.0

8.6

8.0

1.8

MAT 8040

Urn

A\ ..

• * > *

.

i

i

EHV/B-flJBffiL-3.2

• i > i 1 1 • ! < | < 1 1

JSNDL-3.8

i . . .

(Bel B)D-433HL

i n i in it

0^833/

Praqpt vnuraaBter

D-Z2HrtBbold400.

I

EWF/B-VI

. . . . . . i

OOteV

W-TtHKK-1.7B7 To GB.SE %

•

H • t • | i 1 .i K | i | • | 11 • > • | . | . I • 1.

(BBI. B) 0-333 1

•

1 |

S 10 15

Incidwt Energy (1M) 90-Th-832

232rFig. 43: Inter-comparison of prompt nubar of Th

66

HT9D40 FlBBlOBGran Station -5.321 1b 8D9.1 %

8

0 I HIW/B-Vl (Hel. 5) D-233 nmahoM 900.00 taeV0 1 JBffiL-^.2 1HB33 AradMld 400.00 krt

J o i mipi-a.8 m a y o t EMEF/B-YI (Bet, a) o-aaa

IHi ' t 1—i i

Iacidrot Energy («T)

10

90-TiH332

232rFig. 44: Inter-comparison of fission cross sections for Th.

67

1 1 IMi HII

MAT 9010

o

3B

rimtctCrtwaaaotic 13.64 To BOB.I X

0 I BlOr/B-VI (Bel 6)Th-Z32 Tluraahold 500.00 laeVo t JBmL-a.2 Th-aae Tinshoid 400.00 i«y

I ., I . > . I . I • I . , I I I I • ) . I . I • I . ( . I t • I • I • I • I « I • « • I • I « I •• >"•"< • >

j 0 K JlMPL-a.8 Tb-238/0 K EMDF/B-V1 (Bal. 5)Th-g3a |

0.4 0.6

Incident

Fig. 45: Inter-comparison of fission cross sections near threshold for 232Th.Nearly an order of magnitude difference is common near threshold for nayreaction in view of the small magnitude of the cross section. Note furtherthat the threshold in the JENDL-3.2 file is lower at 400 keV compared to500 keV in the ENDF/B-VI (Rev. 5). The JEND1-3.2 values are largerthan those in ENDF/B-VI (Rev. 5) are.

68

MAT 0040 FiselooCRIMES Section

90-T1H332- 5 321 To 74.S8 S

Mit •ttlftjf

0 I HfDT/B-TI (Itol. 5)l1t-232 Itoseliold 500.00 keV0 I JEHDL-3.2 ih-233 Tbnahold 400.00 keV

0 E JINfiL-3.2 !b-232/0 K ENDP/B-VI (Bel. 8)11-832

1.2 1.4 1.6

Incident Energy (tel)

l.B 2 0

•O-Th-232

Fig. 46: Inter-comparison of fission cross sections just above threshold for232Th. Note that the cross sections in the JENDL-3.2 values are larger thanthose in ENDF/B-VI (Rev. 5) by 10 to 20% in 1.4 to 2 MeV regions.

69

MF 8040

* 145

- 140s>

w 135

5 iso0

! 120

115

1.10

o£ 1.05

i.oo

FiaslocCroBStSficti en -1 37H! To B.EB1

K i

2 0

0 I HKHP/B-VI (Rel. 5)nt-23S THreahold 500.00 be?0 E JSNBL-3.2 fh 232 Thrahold 400.00 keY

0 t JEM>L-<?g Th-S38/(> K EHDP/B-VI (Bel

2 .5 3 .0

Incident Energy

3.5 4 0

«O-TlH33e

Fig. 47: Inter-comparison of fission cross sections in the 2-4 MeV energyregion for 232Th. Note that the cross sections in the JENDL-3.2 values aregenerally larger by about 5% than the values provided in ENDF/B-VI(Rev. 5).

70

MAT 9040

I 18S

«•« 1 6 0

5 155

150

148

140

4.0

FlSfliCross L.aBGS Do B.S63 X

•inLktle - I

0 E HIIV/B-VI (Bel. 5)Th-232 Hireshold 3X3.00 teV0 K JINDL-a.2 Th-233 Threshold 400.00 keV

t • | i I < I • I • I « t • t ' I • 4 • I • j ' I i I • I i I i I • I

0 I JEIDL-3.8 Th-238/0 K EW/B-VI (Bel

Incident Qiergy (MeT)

Fig. 48: Inter-comparison of fission cross sections in the 4-6 MeV energyregion for 232Th. Note that the fission cross sections in the JENDL-3.2values are generally larger by about 5% than the values provided inENDF/B-VI (Rev. 5).

71

MAT 9040 FissionGran Section -1 863 To 9.2B3 %

409

~ 380a

8 300

| 250

I| am

160

1.10

1.00

MBfetlft

Emlatlfl

0 E HIW/BMn (Rel. B)Th-232 Threshold 500.0G kfiV0 K JHfflL-S.2 Th-233 Threshold 400.00 keV

I I I-1 t I t I I I t t I I t I I t I I I I I I I I I I t I I I I I I I I I I I t ) * I M t I I I I I I I I I I

0 E JENDL-a.8 Tk-232/0 E SNDP/B-VI (Bel. 5)111-232

6 B 11 IS

Incident Energy (MeY)

Fig. 49: Inter-comparison of fission cross sections in the 6-12 MeV energyregion for 232Th. Note that the fission cross sections in the JENDL-3.2values are generally larger than the values provided in ENDF/B-VI (Rev.5).

72

MOT SOW FiMlonGran Section

90-T1H392- 3 57L To 5 135 S

4*^

560

- 500

360

3D0

0 1.04

« 1.00

0.96

Ml*Kia

— Q I BnV/B-VI (Rel. 5)Tb-Z32 Tbresbold 900.00 leer~ 0 t JHBL-3.2 Th-Z32 Tkreahold 400.00 keV

0 t JBffiL-a.g B»-g38/P I ENDF/S-YI (Bel. 5)1t-g3g |

f

V14 16 IB

Incident E B T O (ifeT)

2Q

90-TtHZ32

Fig. 50: Inter-comparison of fission cross sections in the 12-20 MeVenergy region for Th.

73

InelasticCross Section

90-TiH333-11.17 Ito 459.0 %

MiaIQa

Q E W / ^ H {Bel. 5) B-233 'Ilireshold 49.71C keV0 1 JSHDL-3.2 U-£33 Itasbold 49.213 keV

0 I JSHBL-3.S D-233/0 I EKDF/B-VI (Rel. 5) 0-233

10 10Incidsat

232rFig. 51: Inter-comparison of inelastic cross sections for Th.

74

MAT 6040Cross Station

WJ-Th-232-74.87 To S7.D0 %

*

J

2.0o

I 1.0

M l *Kin

0 K H1OP/B-YI {Rel. 5) U-233 nu-tshold 8.3700 MeV— 0 I JEMDL-3.2 B-833 -RireHhold 6.464? MeV

i I I I I I I I | I ) I I I I I t I | I I I I I t M I | I I I I I I I I I | I I I I I I t I I | I I i I I I M I | I I I I I I I I I |

- O K JENDL-3.2 U-233/0 E EHDF/B-YI (Rel. 5) 0-223

a 10 12 L4 16

Incident Energy (fe?)

ia

W-Th-232

Fig. 52: Inter-comparison of (n, 2n) cross sections. The experimental uncertainty ofthe "raw" data not shown in the figure is generally quoted in the literature (EXFOR)as 10 to 15%. A total of 20 entries in EXFOR exist. The integral measurement [Ref:K. Kobayashi, T.Hashimoto, and I. Kimura, J. Nucl. Sci. Tech, 8, 492, (1971)], forinstance, states an error of 6.7% for the fission spectrum average.

75

MAT 8040Sectio

WJ-T1H332- 6 595 To 83.60 %

10°

101

I '1.4

5 1.8

i1.0

O X MOT/a-VI {Hal. 8) 0-233 Itooaliold 11.4E0 MeV0 K JSHfiL-3.2 D-«33 Thrnsbold 11.60B MeV

o i p-aayo K EHEP/B-YI a) u-a331

14 lfl IB enIneldvni (jfeV)

Fig. 53: Inter-comparison of (n, 3n) cross sections. The EXFOR database containsan entry "SUBENT 21750001 860121" giving a value of 0.85+ 0.15 barns basedon a measurement at 14 MEV following the reference: M.H.McTaggart andH.Goodfellow, Journal of Nuclear Eneregy/AB, 17,437 (1963).

76

MAT9L31 (a.T)Crara Section

91-Pa-Sl100.0 to 5004 %

QE BQV/B-TI {Rel 5)Pa-Z3L

0 S JEHDL-3 2 Pa-231/0 K IKDP/B-VI (Bel. 5)Pa-231

Incident Energy (eT)

231,Fig. 54 Inter-comparison of capture cross sections of Pa

77

HAT 9131 (n.7)CFQBB SsotioD -99.15 To 8004. Z

10

102

ur

if

,0°

I I mn| i i i IIIMJ—i i mint { i i n

Sio"

0 E JEUL-3.2 Pfr-231/0 I EMDF/B-7I (flel. 5)Pb-231

. . . . I . • • . . . . . II r l l qf .

10*' 10*' VIncident

IQ 10 10

«1-Pa-231

Fig. 55: Inter-comparison of capture cross sections of 23lPa in the low energyregion

78

VAT 9131Cross Section

91-P&-231-10Q.0 To ff?.4Z 52

c0

nfn

uto2

2.0

+J 1 .0

0.0

laxtitle ftitlo

0 I HOT/B-T1 (Rel. 5)Pa~Z3L

I » I « I H M ' I ' W •—I • M ) «>• )'*•>•>•) 1—I • I > I < t ' I 'H' I ' l 1 1 « I i | i | I|.|.|I|I

0 E JENDL-3.2 Pa 231

0 E JHfl)L-3.2 P&-231/0 E EHBF/B-VI (Bel. 5)PtH831

10 10

Incident Energy

10 10

Fig. 56: Inter-comparison of capture cross sections of 23lPa in the 1 keV to20 MeV energy region

79

MAT 9131 FissioaCrass Section

«l-Pa-231-99.48 To 47B1 S

to

Ivc .0 *

10*

bits

0 K HTIF/B-VI (Rel. B)Pa-Z3t0 E JB35L-3.2 PkHS31

BU

0 E JKHBL 3 2 Pa^31/0 K EHDF/B-VI (Bel. 5)Pa-K31

Incideot Energy (eV)

Fig. 57: Inter-comparison of fission cross sections of 23lPa. It is interestingto note that, among all actinides 23lPa has the lowest s wave level spacing<D>OBS = 0.47eV.

MAT 9131 FiaslooCrass Seetioo

91-Pa-Z3136 To 9DB0. X

PB231 flttS 89 HKTOP IEN0L-3.Z

PBZ31 TiyS B9 tSOUF afCF/fi-?I

P B 2 3 1 WI1IS 69 GftOUP IIM9 8 8 C9CDP JBIDL-3.S

10Z * 1Q3 * 10* 106 * 1Q7

Incident Energy (e?)

Fig. 58: Inter-comparison of fission cross sections of 231Pa in "WIMS" 69energy group structure. Note that the normalization in Fig. 57 and Fig. 58are different to show that while reproducing the COMPLOT runs presentedin this paper, this factor should be taken into account.

81

MAT 9131 HastenCran Section -9B.S7 To SE33. X

,0°

li?

10'

-ito

Va.fctU

0 I HW/B-V1 (Bel. 5)Pft-23i

i • i iiniMmii|—• i • nnnim»H • i • i

0 I JIMDL-3.Z FVZ31

0 1 JBffiL-3.2 Ph-231/D K EHSF/fr-VI (Bel

rf* *"'*"'* io8 w6

Iocidrat Energy («?}

10

91-Pa-Sl

Fig. 59: Inter-comparison of fission cross sections of 231Pa in the 1 keV-to 20MeV energy region

82

MAT 9131 Total P 91-Pa-231-fl 915 1b 4.969 %

6.0

40

3.0

80

5.0

4.0

3.0

2.0

Mio

JEKDL-3.Z PA-HI

' | i | ihi'iii i i i i i i i i i | i iH'iii ' i ' i 'Hi'i ' '[iii| i i i imi innn

ffllV/B-Vl PA-Z31

lin.fctloj,!

1.5

0.910 15

Incident Encrgj- (]feT)

00

231iFig. 60: Inter-comparison of total nubar of Pa.

83

MIT 9131 Delayed 91-F&-231-36.36 To -16.53K

0 08

•in InJHtto fctto

0 I RDT/B-VI (Del 5)Pa-Z3l0 I JJTOL-3.2 3

!• I . | • «., | i t i > . | M • » »| •> • ) • ! • I ' I i I i I i K f | • I H« I ' I i | i ! • I > I H l I • I • ! « I » I • ! • I • I •!

IV-231/0 I SKDP/B-VI (BBI .

Fig. 61: Inter-comparison of delayed nubar of Pa.

84

JUT 9131 Proipt vRunoster -4.SB3 TO 9.779 %

6.0

4.6

4.0

3.5

3.0

8.5

1.10

1.06

1.00

D.tf

XisElo|

0 I HDT/B-V! {Rel. 6)P«e23L0 K JBDI^a.2 FW-S31

I • I i I • I • > • I • I H • > • | • I • | • I • I • I • I • | • I . I » | • I • I • I • t • I • I i I » I • I • | i 1 • I • I • I • I • I • t • t • I '

0 1 JBffiL-3.8 P&-231/0 E DJBP/E-VI ( S B I . 5)Pb-23J

10

Incident Ecerey (feY)

15 20

231nFig. 62: Inter-comparison of prompt nubar of Pa.

85

MAT 9137 FiMlflBCraai 8iiotiaD

91-FHB3-9B ee To H7 a z

w 10*

i.!

0°

10*

tfi*

10

iom

Kia

0 I JHM.-3.Z Plt-Zn Thraaholi 400.00 to?)

{ 0 I BTOT/B-VI Pfc-233 ITirertoM 400.00 teY |

7

Incident Know

233,Fig. 63: Inter-comparison of fission cross sections for Pa

86

MAT 8137Gran Sectiaa

Bl-Pa-2333.BBS To U7.9 %

1.2

OB

g 0.4

I 0.8

0.4

2.4

0 2.0

1.2

Ml* Mtoj0 K JIB9L-3.Z IV4233 Threshold 400.00 keT

0 E BIOF/B-TI Fk-2B3 Tfcnahold 4flD.flO teT

IH.Iil.nln.tilHH.timn.l.t-hl.iil.M.lifl'tH.tiHf »Hit»l'|'l-|.HI-ff)-t-l<|i>«|i|iH>i«<l'l-n|.

0 K BW/B-TI Po-233/0

• r *~r - '

3 4 S

Iacident ^er^j («eT)

a ?

Fig. 64: Inter-comparison of fission cross sections in the 1-7 MeV energyregion for 233Pa

87

MIT 9197Cran Bestial

W-ft-233-100.0 To 9999 X

i

no#4

•mM -*

o x amfo-n Pfc-Z33^ 1 " " "---'T • • " " | • " - " " I * I " • " t

fc*l"^Mlft

Km

M »l '•'•»< 4 L L H • H t ' - H *l

•H *i H *i ' " H »•'•»<< ' " " H «-fw4 »

0 1 JSMDL-3 2 IV233/0 IEHDP/B-YIT

. ..I . . .J

4 _ , 4 «

•••Hi I » I H H

Incidrai Zoergy («7) 91-AH833

233TFig. 65: Inter-comparison of capture cross sections for Pa

MAT 8137 (n.7)Cran Section

100 I BTOF/b-VI FH233

ao

104

0

4>

1.06

1.00

0.95

0 I JHfflL-3-Z Fa-233

0 1 JlMDL-3.g Pfr-233/D I Bflff/B-Vl fa-233

91-P&-233-4.290 To 6.0B7 S

Mio

H

-rrt ,-M.^MI » . M . - . - , - l . J -„ I . . . . . ..J

• i t i » 4 n I T - t i J T , t i 5 7 . a s I T n s a i r ,ir if iS3 if le1 iou

IO1

Incident Energf («Y)

Fig. 66: Inter-comparison of capture cross sections in the low energy regionfor233Pa

89

MAT 9137

10

10*

tf

0

+1

10

91-F&-233-98.47 To 9999. 2

0 1 JBffiL-3.2 P^-233/O K

10

Fig. 67: Inter-comparison of capture cross sections in the resolved-unresolved energy region for Pa

90

wmr ei-Pa-233-11 . B9 To ffl.12 %

0 E JHJDL-3.2 Pa-233/0 E ENDT/B-VI Pa-233

Energy (eT)

Fig. 68: Inter-comparison of capture cross sections in the 1-20 keV energyregion for 233Pa

91

ureiar MCxttB SBCtlQB

9l-fa-233-19.B3 To 106 2 2

0 I JBtoL-3.2 Pn-233/ft K EWDF/B-V1 fti-333

Fig. 69: Inter-comparison of capture cross sections in the 20 keV -1 MeVenergy region for 33Pa

92

MAT 9137 (n.7>

10

u•o1

,o8

-100.0 To 47.7L Z

Mitt

0 I HTiy/B-71 Pa-B33

> ' ' • ' ! • I0 I JBBDL-a.g Rt-g33J

I 0 E JIMa,-a.8 Pa-g33/0 K 8MDF/B-YI fa-233 [

Incident Energjr (e?) 91-AH333

Fig. 70: Inter-comparison of capture cross sections in the 1-20 MeV energyregion for 233Pa

93

MAT 9131 Total 9Runuetor

WHPa-233-8 834 To 6.236 X

9.5

5.0

4,5

4.0

3.5

3.0

25

1.19

1.05

g l . O I

0 85

0 K HraP/B-VI {Bel 5)Pa-Z330 E JBEL-3.2 IV-233

0 K JBfl)L-3.g Pa-233/0 K HOff/B-il (Bel. 5)Pa-333 |

15

Incident (fcY)

aa91-Pa-233

Fig. 71: Inter-comparison of total nubar values of 233Pa

94

•AT 8131Gran SBctian -40.14 ID 1740. X

i «?

IO1

0 to1

i •

0 I BlflT/H-VI (RBl. 6)Pa-Z33 Thiwhold B.6B44 IBV

I I I I I I I I t t M I I I I I | I I I I I > > t I | I I I I I I I t I | I I I I I I I > > { M I I M I I I | I I I I I I I I I |

0 I JMPL-a.8 Pa-233/D I Bflff/B-YI (Bal. 5)Pa-833 |

10 1Z 14 16 16

Ineidmt

Fig. 72: Inter-comparison of (n, 2n) cross sections of 233Pa

95

MAT 9131 (n.SB)Cross Station

91-ftrZ33-2D.S6 To 114.6 %

10

2 4

0 , a•* 1 .8

1.8

feiio•is

Q K Om/B-n {Hel. 5)Pa-a3 Ttrffsbold 1Z.232 KeV0 E JSHDL-3.2 h-233 Thnshold 12.130 MeV

4 ' I • I • I • \ > I • > • I • I • | • I • I • > » I • | • I • ) • I • I • | • I • I • I • I • | • I • I • I • t • | • I • I • I • I • \ • I • I • I i

0 K JSHDL-a.8 Ph-233/0 E SKDF/B-VI (Bel. 5)Pa-333

13 14 15 16 17 IB 19 20

Incident Energy (feY) 91-P&-233

Fig. 73: Inter-comparison of capture cross sections in the 1-20 MeV energyregion for 233Pa

96

MAT 9226 (n.r)Crora Section

92-U-2343.222 To 83 84 5

o

!

0

5

D-S34/G E JIM3IX3.2 D-234

^ , , . , . , , . r ^ , . ^..yylI • J A...4.Y.I , ^ ^ . t T . l

1.1

Energy («T)

Fig. 74: Inter-comparison of capture cross sections of 234U in the low energyregion up to 2 eV.

97

MAT9S6 (n.r)Crass Section

«B-ff -234-56.73 To 62.01 %

Incident Energy (e?) -234

Fig. 75: Inter-comparison of capture cross sections of 234U in the energyregion in the 2-40 eV energy region.

98

MAT 8306-53.63 To 37.10 S

10

10*

i.s

e 1.2

I O.g

0.4

Ea fafetie

0 K JSHSL-3.!! 0-234

• I « ! • I • ! • ! • ) • ! i > • ) • 8« > • 8 • I • K H I ' H I • | • I H H « I • I • >t« l« H I • H l» H t • H | »l »l • ) •« H

0 E BRIV/EhVI 11-334

| . ! • ! • ! ' ! • I i I • I t | r | I M i l l ' I • ! i | l | < | l | » | ' | i | « i ' l i | » 4 » a . { . . ) . } t « . [ . j . ) . | g

0 E ETOF/B-VI B-&4/Q K JBNDLr-3.8 D-234]i '

• • • ' « t i ' - ' - i > ^ . f . • . i i . • . • . > . . ̂ . . a- JUJL

89 60

Incident

100

» « « >

B . h . » - » • « . H . l ^ B . t » . » - . t . . . . I , . ,. f . 1 • . . . .

IS)

-Z34

Fig. 76: Inter-comparison of capture cross sections of 234U in the energyregion in the 40-130 eV energy region.

99

Cross Ssction-234

-S0.B9 To 842 B X

Incident Energy (eT) «3-0 -834

Fig. 77: Inter-comparison of capture cross sections of 234U in the energyregion in the 120 eV - 1.5 keV energy region.

100

M4TS226Cms Ss&im

92HJ-234-4.8119 TD ZD.90 %

3.0

eo

§ 1.0

3.0

8.0

1.0

120

ftr—hsivu

0 I JBffil-3.2 D-234

> < ! • ! « > • I l l ' ! • H»|'f n u m . mi|i.)i

0 I Enff/B-YI 0-234

* » > ' ! » ! « ! • > • l » l » l » H I ' | I | I | I | •! i H t ' l • ! • { > t > \ . | . | » H 1 • » ° l ° I H i l « | « I ' I ' ! • ! • > • H I ' » <

0 E HIDF/fr-YI IH234/0 C JBNDL-3.S

B 10

92-0-234

Fig. 78: Inter-comparison of capture cross sections of 234U in the energyregion in the 1.5 -10 keV energy region.

101

MAT 9226 (n.r)CRMB Section 4.6EQ9 To 83.63

Incident Energy (eY)

10

920-234

Fig. 79: Tnter-comparison of capture cross sections of 234U in the energyregion in the 10 keV - 1 MeV energy region.

102

MAT 9226 Guy)Cross

n

jj 104

to

10

ID1

10

Q I JIXDL- .̂g U-234

i ! •

0 E EBW/B VI V-8M/Q K JHfDL 3.2 D-234

10

lacitoi Enacr («T)

W-5-E34-66 19 To 9BBB. X

• I H I >

to

Fig. 80: Inter-comparison of capture cross sections of 234U in the energyregion in the 1-10 MeV energy region.

103

MAT 9228 (H.T)Crews Section

.6*

eoo0

aoo

Jail* Mlfl

10

0 I JHDL-3.2 D-234

0 E BTOP/B-7I D-234/0 E

14

incident

m

18

9999.9 To 9999. 1

Q I ffllf/B-Vl D-fiat |

ia 20

92-U-234

Fig. 81: Inter-comparison of capture cross sections of 234U in the energyregion in the 10 -20 MeV energy region. The discrepancy is a factor ofseveral hundreds.

104

799.9 !fo 7B13. X

jjIO*

10

u

30

o

I 40

Mi*

0 E JSHEL-a.Z D-234

o s ranr/s-vi D-SU

I • I ililO'1'H

0 E HfflF/B-YI D-S54/0 t JM)L-3 8 D-234 j

a j ' i ' f ' i ki'h'i"

Incident Energy (e?)

tin

Fig. 82: Inter-comparison of fission cross sections of 234U in the energyregion in the 10'5 to -2 eV energy region. Note that the value of fission crosssection (6.22mb) at the thermal energy in the JENDL-3.2 is ~ 75 timessmaller than the value in the ENDF/B-VI (Rev. 5) file. A recentmeasurement by C. Wagemans et al., yielded39 a value of (300 ± 20) mb towhich the value in ENDF/B-VI (Rev. 5) is closer (464 mb).

105

FissionCroaa Section

Iwrtwd-72. OE To 795.9

UMtoJ,

.24

0 I <JBDL-3.E 0-234

• — I ) • . . - . »

10*

0 I 0-S34

.(....HnHIMUI...^ H . 1 1 . » « . . . |

0 1 EHST/B-VI D-834/0 K JENDL-3.2 D-234

T T10"

Incifcai Enesf7 (eT)

a 4

82-^-4234

Fig. 83: Inter-comparison of fission cross sections of 234U in the energyregion in the 2 to 40 eV energy regions.

106

•AT 8335

10

!

10

.010

id*

10

o 10°

16*

Croaa Soetlan

0 E HfDf/B-YI 0-834/0 K JBiDL-a.8 D-334

IT

-90.71 To 837.0 *

tetloUs

'in i r

t—r

Incidmt Energy («?)

ioa

QSt-Q -834

Fig. 84: Inter-comparison of fission cross sections of 234U in the energyregion in the 0.1 to 1.5 keV energy region.

107

SAT FlasJoeCrass Section

90-0-234-66.41 to K1.B2 %

~ IB

ie

6

8•rl

3

1.8

i.e

0.6

Hafctlftl

•I 0 I JIMBL-3.g D-234}

H'|.|i|il'« I l l l I • I ' I ' • ' • ! •

0 I HW/B-TI U-ZM

H i >i !• l i H l i 11 l« I ' [ ' I I t i | «t K ' l i ) ' H I > } i | » l i f I l l i l H 11 H i 11 11 | i H H I •

0 E HW/&-VI D-234/0 S JEHS/-3.2 0-234

Incident Energj (KieY)

10

Fig. 85: Inter-comparison of fission cross sections of 234U in the energyregion in the 1.5 -10 keV energy region.

108

FlsslcaCraaa SeeUoi

-234-40.14 TD 103 i

0 1 HTOP/fr-VI B-234/0 I JENDL-3.8 D-SS4

10

Fig. 86: Inter-comparison of fission cross sections of 234U in the energyregion in the 10 keV - 1 MeV energy region.

109

W9S&

2.4

~ 2.0

I "0

ea

0

i

1.8

3.0

1.6

1.8

1.06

S 00

0.96 I

10

FisBloeCram Sectim

0 E imL-3.2 D-Z34

0 K BRW/B-VI 0-234

0 1 HW/B-VI D-234/0 S JEW3K3.2 D-234

92-U-234- 4 579 To 3 78fl X

linmiMl |n.mi|iiw|;

T ~t—"i—r

Incident Knergy («?}

10

Fig. 87: Inter-comparison of fission cross sections of 234U in the energyregion in the 1-10 MeV energy region.

FISBiOB

2.4

I6C 80c0

8.0

1.05

•j 100

0 96

ID

E i

0 I JHDL-3.2 D-Z3i

Q t HCT/B-TI P-834

14 16

Incident Brav (feY)

- 6 915 1b 4.B13

- I

Q g BOT/B-VI 0-234/0 K

18 S3

Fig. 88: Inter-comparison of fission cross sections of 234U in the energyregion in the 10 to 20 MeV energy regions.

i n

MAT 8235 Proipt Pflunuwter

i

5.0

4.0

3.0

5.0

4.0

3.0

1.01

1.00

O.ffi

l u

0 E JQIDL-3.2 0-Z34

m i . i m n i»i• 11n}»n n i • i• 11ni • i»i• j»n11 n m ' tn»

Q K mtjW-Hl 0-234

og aw/B-yi D-234/Q g

-0 633 3b 0.204 1

MUe

1111 • m i n i •

i l l . l . l . l

5 10

Incident Ener£f (le?)

15 30

SHJ -€34

Fig. 89: Inter-comparison of prompt nubar of U.

112

o

14

12

10

B

14

IS

10

8

1.8

1 n

0.6

HAT

Urn

tat

• —

•

•

• 1 '

-

8326

4*

01

i i i i i,,,,_,, fi m

1 1 I I I

01

iufell*

Delayed?Fternster

JHDL-3.2 U-234

\BOT/B-FI D-S14

\ \

i i i i i i • i i i i

' ' ' ' I 'fflW/B-71 D-234/0 E JEWa^3.2 D-234

\

\ /

V

-17.B8 to 23.21 X

•

• i • r

•

• • I

-

5 10

Iscident •Bmergf (ifeT) ^-9-234

234TFig. 90: Inter-comparison of delayed nubar of U.

113

HAT 3226 Total vVarmeter

S0-U-234527 To 0.148 %

6.0

4.0

{ < • » » j i . j i | i | • ( i | » | < | « [ i 1 i | 1 1 i ( i ( • u i • I > t » | ' I ' « ' I t | • [ i I i < i H I ' ( t I i [ i | • » ••* ' ) H ' «

5.0

4.0

3.0

I 01

0

5 1.00

0 89

fasMlo

0 E JXNDL-3.2 U-234

Q K BTOF/B-?!

I ! ' • > ' I • I » l » I • I • ! < I » I e | ) . I i ) . ) . I . | •••• ( < ) • < I H « I ' l » l • I » I • ! * < • I • « • I '

0 E BTOF/B-?! D-334/0 K JEHPL^.g 0-834]

10

Energy (leY)

15 20

92-U -234

234,Fig. 91: Inter-comparison of prompt nubar of U.

114

MM1 8219 ProiptUFtameter

0

i

6.0

5,0

4.0

3.0

60

6.0

4.0

3.0

1.0

0.9

0.B

f . | » f

0 I JINDL-3.2 U-233/0 K ENDF/B-TI D-232

i.

10

Incident Energy OfeT)

-8L.&B To -G.18TC

15 m

232TFig. 92: Inter-comparison of prompt nubar of U.

115

Delayed 9ftrasster

6.0

4.0

3.0

Mia Mte

aa §.0

* 4.0

3.0

2.0

o5 1.6

1.2

0 E HOT/EH?! B-23Z

0 E JHBL-3.B U-238

) . I • [ i

0 E JEKDL-3.2 U-232/0 E EKDF/B-7I 0-232

f

5 10

Inci&nt Biergy (HeT)

82-D-25214.42 To 90.68 5

!•

15 20

92-fl -£32

Fig. 93: Inter-comparison of delayed nubar of U.

116

MAT 8219

JS 10°

o

10

FiasJeaCras Section

I ' I 1 » ^ M t ' l ^ I HMHJ <i«iWJ I ' I f ' t j l ' ) i | »

Q E JSHDL-3.2 D-232/Q C BJQF/B-71 D-233

92-^-232-59.90 To 9999. 5

l)i|«j I il'lilj I 'l'l«j

Incident Energy (e?) 82-9 -838

232TFig. 94: Inier-comparison of fission cross sections of U.

117

MAT 8319 (n.7)Croaa Section -39 EE To 9399.

Q 10°

•o4

IP8

10

f

T J • - -'••»-5Mto

0 E JUDL-a.Z V-22EOIBW/B-VI {Rel. 5} U-838

(fel. 5J D-23S/0 I JESBL-3,2 U-23S

Incident Energy («?) 90-9 -232

232TFig. 95: Inter-comparison of capture cross sections of U.

118

MT 8319Crofls SoctioB -99.B2 Tb - ® 9K

15'

C0

10

0 1 HOT/B-7I D-23Z Ifarodnld 7 .316 IeV

« t « M > I M | I I I « t I I I > j I I I I I I I I I \ M I t I I I I I | I I I I M I > > | t I I I I I I I

o E JHBL-3.2 7.

| I I I !> I I I I | I I I M I I I I | t r I I I I I I I | I I ) t I I I I I | I I I I I I I I » j I I I I I I I I I |

0 I JHiBL-a.8 &-23B/0 K Bffif/B-7I

a 10 IS 14 16 18

Incideat Ecer£7 (JfeY)

2X3

tg-Q -232

Fig. 96: Inter-comparison of (n, 2n) cross sections of 232U. The values inJENDL-3.2 are not in tune with systematics and are too low by nearly afactor of 10.

119

(a.Sn)Crass Section -99.85 7b -SB.7S8

10

0

0.04

0.03

0.01

Misl i s

0 I BTCT/R-?! D-23E Ttansdnld 13 210 HeV

) ) M HI | I I M II I I I | H I I I I I I l|)l I I I H ) I | I I I I I I I II [ I I I H I I I I | I U I IH I I f

Q E JEMDL-3.2 0-232 ttireatold 13.210 He?

I ( M I H I | I I I I I I M I 11 M I I I I I I | I H I H I I I 11 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 |

0 E JSHDL-3.8 P-232/0 S ENLP/B-VI 0-232

Fig. 97: Inter-comparison of (n, 3n) cross sections of U

120

SAT 9034 (n.7)Cross Section

W-T1H33O-93.99 1b 9999. %

! w1

to

fo1 0

tuintj i mm) i •t.i'nj i mt»| i itiutj >'t<t»i i mnH »| «inwl I IUMJ imiiij I I | I I«{ i

D ( B(Df/B-VI n-230/D I JESBL-3.2 Th2»

* 10* ' IS3 ' 1? 'Incident Energy (cY)

ft* 1 * 9 ' 1 • A * » 5 * fi» 7

10° 101 10Z iO3 104 105 IO6 107

9O-T1H330

230nFig. 98: Inter-comparison of capture cross sections of Th.

121

MAT 9004

10

n 4- 10

1.2

OB

0.0

Croes Section90-T1H230

-43.B3 Ib 6.047 2

ftwhrt

* " T-WTl-J

o i JBIDL-3.2 nzao

0 I HUff/B-VI Th-23D

Incident Energy (e?)

101

fell*

0 K Hlff/MI ib-230/0 I MDL-3.2 ThSSQ

r.

Fig. 99: Inter-comparison of capture cross sections of 230Th in the lowenergy region.

122

MAT 9034

? l^* 1 0 °

IS2

. I O 3

rf

0 I Bfig/B-YI ft-290/D K

mmfpIncident Energy («T) tO-Th-230

Fig. 100: inter-comparison of capture cross sections of Th in 100 eV to 2keV energy region.

123

MAT 9034 FiaslOBCrass Section

W-T1H230-69.05 to 245 9 2

0 X JEBBL-3.E n s a o ftreslwld 400.00 be?

Q I BUff/H-lTI ThrZ3D Threahold 246.00 e7

1V230/D E JHTCL-3.2 T12M

10 105 ' * " 10"

Incident Energy

2.10nFig. 101: Inter-comparison of fission cross sections of Th

124

HAT 8034 fission-34.OT % 43.84 %

800

TOO

600

500

400

300

200

1.8

e•M 1 ?

I0.8

0911

InMl*

tiafctift,,

Q I BTOF/B-VI (Bel. 5)th-«3Q ThresboM 24800 eV0 1 JHIDL-3.2 th-230 Threshold 400.00 ke?

J&

(Bel.

•vm10

Energy (eY)

Fig. 102: Inter-comparison of fission cross sections of 230Th in ! to 20 MeVenergy region.

125

HAT 8034 (Cross Section 9B1 To 1318. %

^ 10

u

ao

I

IUktlo

Q E JSHDL-3.2 TbZaQ Threabold 6.6211 Ue?

I I M I I | I I 1 II I I II j M I I I I I e I | I I I I I i I I if-H-H-i i I I I | I I M I I I It | M I M I I I I )

0 E Bnv/B-TI Th-Z8 Threshold 6.82L1

I I I I I [ I M M M I I j I I I I I I I I I | I I I t M I 1 I } H-+-H-H-) I | I I I I M M I [ I I I I I I I i I |

0 E BTCF/B-VI n-230/0 K JBiDL-3.2 Tfa23Q

B 10 12 14 l€ IB m

Incident Eaergy (M) 90-Ttr230

230nFig. 103: Inter-comparison of (n, 2n) cross sections of Th

126

HAT9KHCross Section

9O-TIH23O-91.18 3b -00 9BK

10sc

I

0 *°

10

l 0

-3tir0.8

0 0.4

I.

Viatetla

12

Q I JXHI&-3.8 TliZ30 Ibreahnld 12 033 JteV

l . f l > l • I . I • > « » • | t ( • I • ; • i » I • I • « « • » ! ' I ' | I |HIM'HI'M'IH

0 I EKDP/B-VI Th-230 Threshold 13.0B3 VcT

0 E

. I i ) < I < | . l i » • I ' < • ! • « i » • > • > • > • < | . i I • I i I • I t I . i . t . ) •

14 16

Incited

18 3D

W-Th-230

230nFig. 104: Inter-comparison of (n, 3n) cross sections of Th

127

APPENDIX A

The material presented in this Appendix is rather a well known "solved" problem. Theelastic and the total cross sections turned out to be negative in the reconstructed resonance crosssection line shapes in the case of several isotopes in the case of earlier versions of the ENDF/Bfile. Nevertheless the data of the isotopes of the thorium fuel cycle in ENDF/B-VI (Rev. 5) is acarry over from earlier versions and JEF-2.2 is also a carry over from ENDF/B-V. The problemof presence of negative elastic cross sections persists. This Appendix discusses this problem as atutorial for those who are not familiar. This problem is well known.x'6 Since negative values ofcross sections are by definition unpfiysical, this problem was solved in ENDF/B-VI by usingReich Moore formalism in many of important isotopes. The problem of appearance of negativecross sections is still present for some isotopes in ENDF/B-VI (Rev. 5). For instance, in the caseof 230Th the resolved resonance region is described by Single Level Breit Wigner parametersadopted from the "Barn book" BNL-325 and extends up to 251 eV in ENDF/B-VI (Rev. 5). Inthe reconstructed point cross section file, i.e., the output file of the RECENT code, the scatteringcross sections are unphysical negative values in some energy regions in the ENDF/B-VI (Rev.5)file. Since the RECENT code correctly reflects the quality of the evaluated data file, theevaluated file needs improvement. See Fig. A.I for an inter-comparison of ENDF/B-VI (Rev. 5)with JEF-2.2

EXTRACT FROM THE JEF-2.2 File:

90

----

**

**

*** *

-TH-230 NEA

—JEF-2INCIDENT

RCOM-JUN82 SCIENTIFIC CO-ORDINATION GROUP 9034DIST-JAN92MATERIAL 9034

NEUTRON DATAENDF-6 FORMAT

JEF-2

920101 9034903490349034

I .1. .1. .I. . • . » • ! .1. _l. • I •. 1. ^ s r* ^ ^ m

DATA WERE TAKEN FROM ENDF/B-V(MAT=8030).

17-DEC-8426-DEC-843-JAN-85:

31-MAR-88:

************

RADIOACTIVE DECAY DATA DELETED.Q-VALUE FOR MT=iO2 CORRECTEDRESONANCE PARAM. CHANGED TO ORIGINALCHANGE OF THE FLAG FROM SINGLE LEVELBREIT-WIGNER RESONANCE PARAMETERS

*9034*9034

90349034

SINGLE-LEVEL. 9034TO MULTI LEVEL9034

9034****************************************** **********go34

HEDL EVAL-NOV77 MANNDIST-DEC78

90349034

790307 90349034

14511451145114511451

145114S11451

14511451145114511451145114511451145114511451

56789

101112

1314151617181920212223

As mentioned in the above comments in the electronic file of 230Th in JEF-2.2, change ofthe flag from single level to multi level Breit-Wigner resonance parameters was effected whileadopting the data of ENDF/B-V. The impact of this change is shown in the comparison graphspresented in Figs. A.I to A. 3. While the capture is unaffected, the elastic cross sections are allnon-negative in the reconstructed line shapes of the JEF-2.2 file. However there are significantdiscrepancies in the total and elastic cross sections between ENDF/B-VI (Rev. 5) and JEF-2.2.

128

Whether the intent of the experimentally measured values/evaluator has been unaffected or not isa question for examination.

BAT 9034

10

a\ 10IHo3

o

i

10

1.0.1

1 00

0.89

(n.7)Cross Section

W-Tfe-230-O.09B Tte 0.GS8 %

I • l«l*4 ' ' " H ' ' " H '< * "H I'IH»|

BfflF/B-VI Bel 5 Tb-aaO/jeffl.2 Ih-230

J . J

10* V * IS8 * 101 ^ 10°Incideat Energy (e?)

Fig. A. 1 Comparison of capture cross sections showing essential agreement betweenJEF-2.2 and ENDF/B-VI (Rev. 5).

129

MAT 9034

10

c0

!

10*

10

10

10°

OB

i ••*

0 0

ElasticCran Section

WO-Th-230-100.0 Tto 9B89. X

EMPF/̂ B-VI Rel S Th-230

iSOOF/B-VI Bel 5 Tb-230/jofg 2

. .1 . . . .

to4 IO1 4 io° io l * ioa 4 io3 to4 * io5 4 i

Incident Energy

1090-TLHOO

Fig. A. 2: This figure illustrates that though both the data files use the same resonanceparameters, the problem of negative elastic cross sections at some energies is eliminated in JEF-2 2 by interpreting the resonance parameters as Multi-Level Breit Wigner parameters. Theoriginal intent of the transmission experiment may not however be preserved.

130

HAT £034 TotalCrass Section

80-T1H330-30.78 To 5*.36 %

EMPT/B-VI Bel 5 Th-g3Dj

Incident Enere/ «0-Th-230

Fig. A. 3. Discrepancies in the total cross sections in the resonance region are significantthrough the basic evaluated data in JEF-2.2 is taken from ENDF/B-V file. The possiblereason for this is the interpretation of SLBW resonance parameters as MLBW parametersto avoid the occurrence of negative elastic cross sections.

131

IEFE.2 D-S34 aoro Kelvin

10

10*

BiCi'/B-VI B-f3t/Jffl8.g D-aa4 saero Kelvin 1

. , <^ J ,

to3 ' i io3 l to4 ' ioB ' io6

Incidrat «2-D -234

Fig. A 4 This comparison confirms that the ENDF/B-VI (Rev. 5) and the JEF-2.2 areessentially identical except for a problem at the boundary of the resolved resonanceregion. (See text)

132

84T9236 GUT) .Section

S3-P-Z34Tto 0.044 S

0

10°

is2

10o *5 IO1

EWDF/B-VI P-334 |

EKEF/B-VI U-234/JBPg.e D-234 zero

1.S0

Incident Energf

1.51

98-0

Fig. A. 5: This figure illustrates the reason for the discrepancy shown on the right side onthe top of Fig. A. 4. The upper end of resolved resonance region is 1.499 keV in JEF-2.2which is formed from ENDF/B-VI but which has 1.500 keV as the upper end of resolvedresonance region.

133

JEF-2INCIDENTENDF-6

*************

* JEF-2

MATERIAL 9040NEUTRON DATAFORMAT***************************************

* DATA WERE TAKEN FROM ENDF/B-IV(MAT=1296) , AND* TO ENDF/B-V FORMAT AT THE NEA DATA BANK.*************

* 17-AUG-84* 17-DEC-84* 3-JAN-85* 31-MAR-88*

**************************************>

: INEL. THRESH. ENERGIES CORRECTED.: FISSION YIELD DATA DELETED.: RESONANCE PARAM. CHANGED TO ORIGINAL: CHANGE OF THE FLAG FROM SINGLE LEVELBREIT-WIGNER RESONANCE PARAMETERS

90409040904 C

********* ****** 9040

*9040TRANSLATED *9040

*9040t******+**+*+**904Q

90409040

SINGLE-LEVEL. 904 0TO MULTI LEVEL9040

9040

t**************90409040

1451145114511451145114511451145114511451145114511451

14511451

789

10111213141516171819

2021

The data of 232Th in JEF-2.2 basically follows ENDF/B-IV as shown above in the extractfrom the comment Section. There are significant differences between JEF-2.2 and ENDF/B-VIin various cross sections. These comparison graphs are available with the authors for theinterested reader.

For the non- familiar reader, we state some basic remarks below:

Relationship between File 2 and File 3 ofENDF/B

The- purpose of this section is to briefly recall the ENDF/B conventions for therepresentation of cross sections in the resonance ranges For the convenience of readers, who arenot familiar with the ENDF/B conventions, the roles of Files 2 and 3 of ENDF/B are brieflyrecalled. The appearance of negative values of the resonance reconstructed elastic cross sectionsin the resonance region is mentioned. For more details, the interested reader may refer to theliterature1 "3 on ENDF/B system.

The ENDF/B "tapes' are subdivided internally into "materials, (MAT), "file' (MF) and"sections" (MT). A MAT contains all data for a particular evaluation for an element or isotope[for example, MAT 9222 is an evaluation for 233U in ENDF/B-VI (Rev 5)]. A "file" contains aparticular type of data for that MAT: MF = 2 contains resonance parameters; MF = 3 containscross section vs. energy data. A "section" refers to a particular reaction for example, MT = 2represents elastic scattering cross section data and MT = 102 the neutron-induced capture crosssection. In File 2, the resonance data is contained in the form of resolved and/or unresolvedresonance parameters. In order to obtain the total cross section (MT - 1), the radiative capturecross section (MT = 102), fission cross section (MT ~ 18) and elastic-scattering cross sections(MT = 2) and the cross sections which are calculated from these parameters using the

134

recommended formalism must be added to the background cross sections given in File 3. Thecontributions from Files 2 and 3 must be summed to define the correct cross sections for neutronenergies within the energy ranges specified for the resolved and/or unresolved resonanceparameters. When single-level resonance parameters are used, the cross sections given in File 3may contain, for example, corrections (background cross section) to account for multilevelinterference effects that were apparent in the experimental data but could not be reproduced by aset of single-level resonance parameters. This procedure defeats the very purposes of theresonance parameterization, as pointed out4 by Poenitz and De Saussure. Derrien6 hasrecommended that multilevel formalisms be used to represent measured data if the single-levelformalism cannot reproduce the measured data without a nonsmooth background. The crosssections in File 3 to be added to the resonance contribution in File 2 are specified at 0 K, and areintended to be combined with File 2 data calculated at 0 K.

The Single Level Breit-Wigner (SLBW) formalism as defined in ENDF/B does not leadto nonnegative cross sections when contributions from different individual levels aresuperimposed by addition. The problem arises in many nuclei; it is particularly severe in thecase of even-even nuclei, with spin 1 = 0, for which interference between the resonance andpotential scattering can lead to very low (positive) cross-section minima for elastic scattering forpronounced individual s-wave resonances. If the interference minima of two close lyingresonances of this type overlap just below their peak energies, the addition of their resonance andinterference cross sections and the cross section for potential scattering using the ENDF/Bsingle-level formalism can lead to unrealistic negative values of the scattering and total crosssections, even after Doppler broadening has been applied. The superposition of separate SLBWcontributions by addition is clearly incorrect. In cross section theory, scattering amplitude mustbe added for the individual levels, before the cross section is calculated as the absolute square ofthe total amplitude. This is done in the multilevel resonance formalism, but the order of the twooperations is reversed (incorrectly) in the SLBW for in the form, which is recommended for usein the ENDFIB formalism1.

When negative cross sections result from the use of the single level formalism, theproblem can be mechanically avoided by interpreting the parameters as multilevel. However,generally, the resulting cross sections will not reproduce the intent of the evaluator and mayresult in poorer agreement with experimental measurements. A change of formalism mayrequire re-evaluation of the resonance parameters to obtain the best agreement with experimentaldata. It was the intention to eliminate all problems connected with negative cross sections inENDF/B-V by not using the single-level formalism in any evaluations as pointed out2'3< 5^ in theliterature.

The JEF-2.2 is a carry over from ENDF/B-V but with the employment of the resonanceparameters in Multi-Level Breit Wigner formalism. This approach avoids the occurrence ofnegative cross sections.

It is interesting to note that there are discrepancies between ENDF/B-VI (Rev. 5) and theJEF-2.2 file purely because of a minor coding difference. For instance in Fig. A.4, presented is agraph inter-comparing the capture cross section of 234U in the two files. The ratio is unity everywhere showing that the two curves are visibly identical but the COMPLOT program shows, on

135

the top of the right hand side, a discrepancy of -99.48% which is larger than the 0.1% toleranceused in the resonance reconstruction process. This can be understood by zooming the portion ofthe graph as in Fig. A. 5 near the resolved resonance region. The ENDF/B-VI uses an upper limitof 1.5 keV whereas the JEFF-2.2 file uses 1.499 keV. This results in the discrepancy that we areseeing in capture, total, fission and elastic cross sections. Note that both ENDF/B-VT (Rev. 5)and JEF-2.2 use MLBW parameters for 234U.

References to Appendix-A

1 D. Garber, C. Dunford, S. Pearlstein, Report BNL-NCS-50496 (1975), Brookhaven NationalLaboratory

2 R. Kinsey, Report BNL-NCS-50496 (1979) Brookhaven National Laboratory3 Magurno, Report BNL-NCS-50496 (1983), Brookhaven National Laboratory4. W. P. Poenitz and DeSaussure G. (1984) Prog. Nucl. Energy 13, 129 (1984)5. DeSaussure G et al., Olsen D. K., and Perez R.B., Nucl. Sci. Eng., 61, 496 (1976)6. H Derrien, Proceedings on the Conference on Uranium and Plutonium resonance parameters

(D. E Cullen Editor), p. 13, INDC (NDS)-129/GJ (1981), IAEA, Vienna

136

APPENDIX B

Calculations of Production of231 Pa arising from 230Th

In the case of thorium fuel, only the ^ T h isotope is considered to be naturallypresent and assumed to be 100% abundant. However, it has been stated in the literaturethat the isotopic composition of thorium ores varies considerably, depending on theamount of associated uranium and its effect in producing an admixture of 230Th daughter.A survey by P. E. Figgins and H. W. Kirby1, indicated that the ionium content of thoriumores can vary from almost zero up to as much as 11.6%. This report is referred to on p.87 in a book.2 Whether the Indian ores contain similar amount of ionium needs to beassessed. In theory, if a uranium ore has an extremely high U/Th atom ratio (on the orderof 10,000) and is old enough (more than 350,000 years), the isotopic abundance of 230Thcould be greater than 10% as mentioned by Prof Chih-An Huh3

We proceed further in this paper assuming that ionium may be present in the oresin some parts of the country. We make a first assessment of production of ^ P a , takinginto account the destruction of 231Pa and 230Th by fission and capture, ignoring the effectsof (n, 2n) processes and half-lives for decay.

The 69 group cross sections for 230Th were generated as indicated in the flowchartusing LINEAR/ RECENT/ SIGMA1/ GROUPIE code system4. These are infinitedilution cross sections and thus no self-shielding effects are taken into account. Withthese cross sections and group fluxes, the effective one group capture and fission crosssections in the thorium fuel respectively turned out to be 18.13 and 0.03 barns. For " 'Pa,the effective one group capture cross section is 96.40 bams and for fission 0.218 barns.To save space, the 69 group values fluxes, cross sections and reaction rates are nottabulated here but are available separately3. Assuming that 230Th is present with anabundance of 0.025% by weight of Th, the loading of 400 kg in the Indian PHWR 220Mwe reactor (KAPP-1) then gives a 0.1 kg of 230Th as initial inventory. The energygroup containing the first resonance (1.427 eV) in 230Th contributes —50 % and theenergy group containing the second resonance at 17.27 eV ~ 10% to the capture reactionrate leading to the formation of ^'Pa. Our results show that if we assume, for instance,just 0.025% of 230Th in the thorium bundles (400 kg) loaded in 220 MWe PHWRs, weget a net production of ^ 'Pa of about 4.1 grams in 300 days. . This is for an assumedtotal flux of 1 OE+14 in the thorium region. The details of this study are presentedseparately5. The calculations presented here are preliminary in the sense that the 230Thcontent in thorium is arbitrarily assumed to be 0.025% (as compared to the value of zeroto 11.6% in the literature). Further, the calculations, though detailed and from detailedbasic data, do not take into account the effect of self-shielding in 230Th, effects of ""Thon criticality, flux calculations, effects of " 'Pa etc which will become influential athigher abundance of 230Th especially due to the first two resonances ( 1.427 eV and 17.27eV)in230Th.

137

The production is not linear in time due to destruction of 231Pa by absorption ofneutrons. The results for 30 days and 300 days are given Table B. 1

Table B. 1

Days

30

300

Net 231Pa produced in grams.

0.46

4.1

References for Appendix-B

1. P. E. Figgins and H. W. Kirby, "A survey of sources of ionium (230Th )," USAECreport MLM-1349 (1966)

2. Donald C. Stewart, "Data for Radioactive Waste management and NuclearApplications" Wiley-InterScience Publication, John Wiley and Sons (1985).

3. Prof. Chih-An Huh. Taipei, Taiwan, R O C (Email to S. Ganesan, 12 Dec. 99).4. Dermott E. Cullen, 'TREPRO96: ENDF/B Pre-processing Codes", University of

California, Lawrence Livermore National Laboratory, IAEA-NDS-39, obtained fromthe IAEA Nuclear Data Section (1996)

5. S. Ganesan, V. Jagannathan, P. D. Krishnani and DC. Sahni, "Estimation ofproduction of 231Pa from 230Th in PHWRs," Unpublished (1998)

Published by : Dr. Vijai Kumar, Head Library & Information Services DivisionBhabha Atomic Research Centre, Mumbai - 400 085, India.