8.1.2011 1

Methods of Czech VVER

Process Parameters Validation

Jindřich Machek, NRI Rež plc

VVER – 2010

EXPERIENCE AND PERSPECTIVES

01 – 03 November 2010, Prague, Czech Republic

AUTOCLUB CR, Opletalova street 29, Prague 1

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Methods used for validation

Simple physical models (e.g. P-T diagram,

conservation equations)

Special regression model (core exit

temperatures)

Neural network (PEANO)

Transparent network

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P-T diagram used for validation

(condenser of Temelin unit 2)

-97.0

-96.0

-95.0

-94.0

-93.0

-92.0

-91.0

29 30 31 32 33 34 35 36 37

2RM21,2,3T001

2S

D01,2

,3P

001 [

kP

a]

PT1

PT2

PT3

P-T teor

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P-T diagram with invalid measurement (unit 1)

-96.0

-95.5

-95.0

-94.5

-94.0

-93.5

-93.0

29 30 31 32 33 34 35 36 37 38

1RM21,2,3T001

1S

D01,2

,3P

001 [

kP

a]

PT1

PT2

PT3

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Reconstruction of invalid signal pressure calculated from temperature

-97

-97

-96

-96

-95

-95

-94

-94

07/03 06:00 07/03 18:00 08/03 06:00 08/03 18:00

time

1S

D0

1,2

,3P

00

1

1SD01P001_N1

1SD02P001_N2

1SD03P001_N1

1SD02P_calculated

1SD01P_calculated

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Core exit temperatures

Core exit temperatures validation using measurements in the

vicinity

– Specialized method for highly correlated homogenous measurements

only

– Uses 2 – 15 other thermocouple measurements in the vicinity

– Simple and relatively precise model

To = Σ ki Ti

under the condition Σ ki = 1 (isothermal condition).

– Good experience with extrapolation to unknown states (valid during

transients, only slightly increased deviations)

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Core exit temperatures validation – example 1Thermocouple drift 1°C/day

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Core exit temperature validation – example 2

Validation of the T147 measurement

260

265

270

275

280

285

290

295

300

305

14/12/2003 14:52 14/12/2003 15:07 14/12/2003 15:21 14/12/2003 15:36 14/12/2003 15:50 14/12/2003 16:04 14/12/2003 16:19 14/12/2003 16:33

Time

Te

mp

era

ture

[°C

]

T147

Rec_1

Rec_2

To

T144

T164

T165

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Implementation of PEANO at Temelin

Main goal – establish the model for the power production and

validate parameters used for the model

Parameter selection – 35 signals from Temelin Unit 1 and 2

(electric power + II. circuit characteristics),

data from Jan to Apr 2009

Pre-processing – data check using own conversion application

(*.csv →*.dat) . Elimination of gaps (missing data), deleting

records with too many gaps. No filtering, no denoising.

AANN training – all data used simultaneously for training and

validation

Validation using PEANO Batch Monitoring Module

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PEANO results

Frequent overcrossing of ±3σ and ±0.5% of the extent associated with fast transient and resulting in „check“ or „failed“ status of the signal:

Subsequent analyses show probably no serious problem with

measurement quality except following case.

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PEANO results

One systematically invalid measurement found – pressure in the

middle part of the condenser on unit 1

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Electric power validation

Transparent network– Specialised method for complex parameters like unit electric

power

– Easy reasoning

– Solves the problem of stand-by systems

– Precision competitive with AANN (PEANO)

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Transparent network for Temelin

electric output estimate

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Transparent network for Temelin

electric power – comparison with PEANO

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Transparent network for Temelin

electric power – comparison with PEANO (cont.)

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Conclusions

Validation is useful – capable to identify potentially dangerous errors in

the I&C system

PEANO – user friendly tool, enabling to validate the systems without

knowledge of physical relations between variables

PEANO estimates: high precision with known data, problems with

unknown data evaluation, namely during transients

PEANO disadvantages:

– Low capacity

– Frequent request to check validity – some guidance how to do it or coupled

diagnostic system would be welcome

Core exit temperatures validation – in some cases simple correlation is

powerful enough to give equivalent results

Transparent network:

– Easy reasoning

– Accuracy lower than PEANO on known data but reliable even in case of

unknown transients

– Overcomes the problem with stand-by parts

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Thank you for your attention

www.ujv.cz