ML063560065

CENPD-279, Supplement 17, Annual Report on Combustion Engineering ECCS Performance Evaluation Models for Pwrs.

ML063560065
Person / Time
Site:	San Onofre
Issue date:	03/31/2006
From:	Westinghouse
To:	Office of Nuclear Reactor Regulation
References
CENPD-279, Suppl 17
Download: ML063560065 (19)

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Enclosure 1 (14 pages including this page)

Westinghouse Non-Proprietary Class 3 CENPD-279, Supplement 17 March 2006 Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs (OWestinghouse

CENPD-279, Supplement 17 March 2006 LEGAL NOTICE This report was prepared as an account of work performed by Westinghouse Electric Company LLC. Neither Westinghouse Electric Company LLC nor any person acting on its behalf:

A.. Makes any warranty or representation, express or implied including the warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of, any information, apparatus, method or process disclosed in this report.

COPYRIGHT NOTICE This report has been prepared by Westinghouse Electric Company LLC (WEC) and bears a Westinghouse Electric Company LLC copyright notice. Information in this report is the property of.and contains copyright information owned by WEC and/or its subcontractors and suppliers. It is transmitted to you in confidence and trust, and you agree to treat this document and the information contained therein in strict accordance with the terms and conditions of the agreement under which it was provided to you.

You are permitted to make the number of copies of the information contained in this report which are necessary for your internal use in connection with your implementation of the report results for your plant(s) in your normal conduct of business. Should implementation of this report involve a third party, you are permitted to make the number of copies of the information contained in this report which are necessary for the third party's use in supporting your implementation at your plant(s) in your normal conduct of business if you have received the prior, written consent of WEC to transmit this information to a third party or parties. All copies made by you must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.

The NRC is permitted to make the number of copies beyond those necessary for its internal use that are necessary in order to have one copy available for public viewing in the appropriate docket files in the NRC public document room in Washington, DC if the number of copies submitted is insufficient for this purpose, subject to the applicable federal regulations regarding restrictions on public disclosure to the extent such information has been identified as proprietary.

Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.

( Copyright 2006, Westinghouse Electric Company LLC. All rights reserved.

CENPD-279, Supplement 17 March 2006 ABSTRACT This report describes changes to and errors in the Westinghouse Electric Company LLC (Westinghouse) Emergency Core Cooling System (ECCS) performance evaluation models (EMs) for Combustion Engineering (CE) PWRs in calendar year (CY) 2005 per the requirements- of 10CFR50.46. For this reporting period, an error in the Large Break LOCA 1999 EM steam cooling model was identified and corrected. The maximum plant specific impact of this error correction is an increase in the peak cladding temperature (PCT) of 2 OF. Other changes to LOCA analysis methods in CY 2005 did not have an impact on PCT.

The sum of the absolute magnitudes of the generic PCT changes for the large break LOCA 1985 EM from all reports to date continues to be less than I OF excluding plant specific effects. The generic impact on the PCT for the large break LOCA 1999 EM is less than 1.2 OF for plants analyzed with the Automated/Integrated Code System (AICS) and less than 3 OF for plants analyzed with the Advanced AICS (AAICS). There is no generic accumulated change in PCT for the small break LOCA S2M evaluation model. No change occurred in the PCT due to post-LOCA long term cooling issues. The total effect relative to the 50 OF definition of a significant change in PCT for each evaluation model is the sum of the generic effects for that model and plant specific effects, if any, described in Appendices A through F.

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CENPD-279, Supplement 17 March 2006 TABLE OF CONTENTS SectionTitle Page

1.0 INTRODUCTION

1 2.0 COMBUSTION ENGINEERING ECCS EVALUATION MODELS AND CODES 3 3.0 EVALUATION MODEL CHANGES AND ERROR CORRECTIONS 4

4.0 CONCLUSION

S 6

5.0 REFERENCES

7 APPENDICES (Plant Specific Considerations)

A. ARIZONA PUBLIC SERVICE COMPANY (PVNGS Units 1, 2 & 3)

B. CONSTELLATION GENERATION GROUP, LLC (Calvert Cliffs Units 1 & 2)

C. SOUTHERN CALIFORNIA EDISON COMPANY (SONGS Units 2 & 3)

D. DOMINION RESOURCES (Millstone Unit 2)

E. ENTERGY OPERATIONS, INCORPORATED

1. Plant Specific Considerations for Arkansas Nuclear One Unit 2

2. Plant Specific Considerations for Waterford Unit 3 F. FLORIDA POWER AND LIGHT COMPANY (St. Lucie Unit 2)

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CENPD-279, Supplement 17 March 2006

1.0 INTRODUCTION

This report addresses the Nuclear Regulatory Commission (NRC) requirement to report changes and errors in ECCS performance evaluation models. The ECCS Acceptance Criteria, Reference 1, spell out reporting requirements and actions required when errors are corrected or changes are made in an evaluation model or in the application of a model for an operating licensee or construction permittee of a nuclear power plant.

The action requirements in 10CFR50.46(a)(3) are:

1. Each applicant for or holder of an operating license or construction permit shall estimate the effect of any change to or error in an acceptable evaluation model or in the application of such a model to determine if the change or error is significant. For this purpose, a significant change or error is one which results in a calculated peak fuel cladding temperature (PCT) different by more than 50'F from the temperature calculated for the limiting transient using the last acceptable model, or is a cumulation of changes and errors such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50'F.

2. For each change to or error discovered in an acceptable evaluation model or in the application of such a model that affects the temperature calculation, the applicant or licensee shall report the nature of the change or error and its estimated effect on the limiting ECCS analysis to the Commission at least annually as specified in 10CFR50.4.

3. If the change or error is significant, the applicant or licensee shall provide this report within 30 days and include with the report a proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with 10CFR50.46 requirements. This schedule may be developed using an integrated scheduling system previously approved for the facility by the NRC. For those facilities not using an NRC approved integrated scheduling system, a schedule will be established by the NRC staff within 60 days of receipt of the proposed schedule.

4. Any change or error correction that results in a calculated ECCS performance that does not conform to the criteria set forth in paragraph (b) of IOCFR50.46 is a reportable event as described in 10CFR50.55(e), 50.72 and 50.73. The affected applicant or licensee shall propose immediate steps to demonstrate compliance or bring plant design or operation into compliance with 10CFR50.46 requirements.

This report documents the errors corrected in and/or changes to the presently licensed ECCS performance evaluation models for PWRs developed by Combustion Engineering, made in the year covered by this report, which have not been reviewed by the NRC staff. This document is Westinghouse Electric Company LLC 1

CENPD-279, Supplement 17 March 2006 provided to satisfy the reporting requirements of the second item above. Reports for earlier years are given in References 2-18.

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CENPD-279, Supplement 17 March-2006 2.0 COMBUSTION ENGINEERING ECCS EVALUATION MODELS AND CODES Four evaluation models (EM) for ECCS performance analysis of Combustion Engineering (CE) designed PWRs are described in topical reports, are licensed by the NRC, and are covered by the provisions of 10CFR50.46. The evaluation models for large break LOCA (LBLOCA) are the 1985 EM and the 1999 EM. For the small break LOCA, the evaluation model is the S2M EM.

Post-LOCA long term cooling (LTC) analyses use the LTC evaluation model.

Several digital computer codes are used to do ECCS performance analyses of PWRs for the evaluation models described above that are covered by the provisions of 10CFR50.46. Those for LBLOCA calculations are CEFLASH-4A, COMPERC-Il, HCROSS, PARCH, STRIKIN-II, and COMZIRC. CEFLASH-4AS is used in conjunction with COMPERC-II, STRIKIN-JI, and PARCH for SBLOCA calculations. The codes for post-LOCA LTC analyses are BORON, CEPAC, NATFLOW, and CELDA.

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CENPD-279, Supplement 17 March 2006 3.0 EVALUATION MODEL CHANGES AND ERROR CORRECTIONS This section discusses all changes and error corrections implemented in calendar year (CY) 2005 in the ECCS performance evaluation models identified in Section 2.0 that may affect the calculated peak cladding temperature (PCT).

1. LBLOCA Steam Cooling Model Error Correction The LBLOCA Evaluation Model, 1999 EM, has an NRC imposed Safety Evaluation Report (SER) constraint. The constraint stipulates that the steam cooling model in the PARCH module of the STRIKIN-I1 program can be used for calculating the hot rod PCT provided the resulting heat transfer coefficients are no better than those calculated using the FLECHT heat transfer correlation. An error in the implementation of this constraint in the 1999 EM was discovered in calendar year 2005 and was corrected. The error pertains to the STRIKIN-I1 main program not providing the correct limiting FLECHT heat transfer coefficient value to the PARCH module for use in checking thej SER constraint. It was determined that the STRIKIN-I1 program was providing the steam cooling model heat transfer coefficient value from the previous time step for this check.

The error in the STRIKIN-il program was corrected by a coding change to ensure the use of the FLECHT heat transfer coefficient for confirming that the SER constraint was met. The maximum plant specific impact on PCT due to correcting the steam cooling model was an increase of 2 'F. The impact of the correction on PCT for each applicable CE fleet plant is shown in the relevant appendices of this report.

2. Component Model Improvement to Include Effect of Spacer Grids for LBLOCA Analysis The implementation of an Advanced Automated/Integrated Code System (AAICS) was previously identified as a change in the implementation of the 1999 EM LOCA Evaluation Model in the Annual 10 CFR 50.46 Report for calendar year 2004 (Reference 18). A change to the 1999 EM has been implemented since last year's report. This change pertains to the PARCH module of the STRIKIN-II program and was implemented via a component model improvement to include the effects of spacer grids. The improved component model is the 1999 EM steam cooling model for less than 1 in/sec core reflood flow rate. This improvement to the existing 1999 EM component model is intended to be an optional feature of the LBLOCA 1999 EM that is applicable to the CE 16x16 Next Generation Fuel (NGF) design as well as to any other CE fuel design for future applications; The improved model is described in Reference 19 which has been submitted to the NRC for review and approval.

There is no change in PCT with regard to the current analyses of record for the CE fleet plants since the component model improvement mentioned above is not used in these analyses.

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CENPD-279, Supplement 17 March 2006

3. Additional Automation of LOCA Analysis Methods Automation of the LBLOCA and SBLOCA analysis methods using AAICS had been previously reported in last year's 10 CFR 50.46 report (Reference 18). Additional automation of methods was implemented for both the LBLOCA and SBLOCA analyses. For both analyses, the case inputs for various computer case runs were automatically generated using case matrix generation programs. The case inputs refer to input values for simulating a specific LOCA scenario for a specific plant using the EM. The case matrix refers to a set of parametric cases with differing break sizes and/or plant operating conditions.. The utility program CMG99A was used for LBLOCA 1999 EM case matrix generation, while, program CMGS2M was used to create the case matrix for the SBLOCA S2M EM. These programs eliminated much of the manual effort required in setting up LOCA case runs and reduced the potential for errors.

The use of these utility programs did not result in any changes to the EM or any of its components including those controlled by Appendix K. The use of the case matrix generation programs, CMG99A and CMGS2M, for automating the LOCA analyses has no impact on the analysis results, including the PCT.

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CENPD-279, Supplement 17 March 2006

4.0 CONCLUSION

S The correction of errors in LOCA analysis models and/or changes to LOCA analysis methods during CY 2005 had the following impact on LOCA analysis results.

(1) The correction of the steam cooling model in the STRIKIN-Il program of the 1999 EM for LBLOCA results in a maximum plant specific impact on PCT of 2 'F.

(2) The component model improvement to include the effects of spacer grid has no impact on the current analyses of record for CE fleet plants since this improvement is not used in these analyses.

(3) The automation of the LBLOCA and SBLOCA analysis methods for the 1999 EM and S2M EM using the case matrix generation programs, CMG99A and CMGS2M, respectively, has no impact on analysis results, including the PCT.

The sum of the absolute magnitude of the changes in PCT calculated using the 1985 EM for LBLOCA, including those from previous annual reports, References 2-18, remains less than I°F.

The maximum generic impact on PCT calculated with the 1999 EM is less than 3°F (from Reference 18). There are no additional generic PCT changes for the Year 2005 for the 1985 EM and the 1999 EM models. Plant specific LBLOCA considerations for each plant in the CE fleet including the application of the corrected steam cooling model are discussed in Appendices A through F.

Previous plant specific PCT effects for the S2M SBLOCA evaluation model' are discussed in Appendices A through F of Reference 15. There is no previous generic accumulated change in cladding temperature for the S2M EM. There are no additional PCT changes for calendar year 2005 for the S2M evaluation model. Plant specific SBLOCA considerations for each plant in the CE fleet are discussed in Appendices A through F, as applicable.

There is no PCT effect for the post-LOCA long term cooling evaluation model.

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CENPD-279, Supplement 17 .Ma~rch 2006

5.0 REFERENCES

1. "Acceptance Criteria for Emergency Core Cooling Systems for Light Water Nuclear Power Reactors," Code of Federal Regulations, Title 10, Part 50, Section 50.46.

2. "Annual Report on C-E ECCS Codes and Methods for 10CFR50.46," CENPD-279, April, 1989.

3. "Annual Report on C-E ECCS Codes and Methods for 10CFR50.46," CENPD-279, Supplement 1, February, 1990.

4. "Annual Report on C-E ECCS Codes and Methods for 10CFR50.46," CENTpD-279, Supplement 2, April, 1991.

5. "Annual Report on C-E ECCS Codes and Methods for 10CFR50.46," CENPD-279, Supplement 3, April, 1992.

6. "Annual Report on C-E ECCS Codes and Methods for 10CFR5O.46," CENPD-279, Supplement 4, April, 1993.

7. "Annual Report on C-E ECCS Codes and Methods for 10CFR50.46," CENPD-279, Supplement 5, February, 1994.

8. "Annual Report on ABB C-E ECCS Performance Evaluation Models," CENPD-279, Supplement 6, February, 1995.

9. "Annual Report on ABB C-E ECCS Performance Evaluation Models," CENPD-279, Supplement 7, February, 1996.

10. "Annual Report on ABB CE ECCS Performance Evaluation Models," CENPD-279, Supplement 8, February, 1997.

11. "Annual Report on ABB CE ECCS Performance Evaluation Models," CENPD-279, Supplement 9, March, 1998.

12. "Annual Report on ABB CE ECCS Performance Evaluation Models," CENPD-279, Supplement 10, February, 1999.

13. "Annual Report on ABB CE ECCS Performance Evaluation Models," CENPD-279, Supplement 11, March, 2000.

14. "Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs," CENPD-279, Supplement 12, April, 2001.

15. "Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs," CENPD-279, Supplement 13, Rev. 1, April, 2002.

16. "Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs," CENPD-279, Supplement 14, Rev. 1, April, 2003.

17. "Annual Report on Combustion Engineering ECCS. Performance Evaluation Models for PWRs," CENPD-279, Supplement 15, March 2004.

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CENPD-279, Supplement 17 March 2006

18. "Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs," CENTD-279, Supplement 16, March 2005.

19. "CE 16x16 Next Generation Fuel Core Reference Report", WCAP-16500-P, Rev. 0, February 2006.

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CENPD-279, Supplement 17 March 2006 APPENDIX C SOUTHERN CALIFORNIA EDISON COMPANY Plant Specific Considerations for SONGS Units 2 and 3 The 1985 EM was used to perform the LBLOCA analysis for the fuel cycles in operation during 2005 (Cycle 13) for SONGS Units 2 and 3. The steam cooling model error correction in the STRIKIN-II program only applies to the 1999 EM and hence has no. impact on the LBLOCA analysis for SONGS Units 2 and 3. Thus the plant specific impact for the LBLOCA analysis remains the same as for the previous year report (Reference 18) at less than 1 OF.

The plant specific PCT impact for the SBLOCA analysis remains the same as for the previous year report (Reference 18) at 19TF.

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Enclosure 2 (5 pages including this page)

2005 REPORTING PERIOD LOSS OF COOLANT ACCIDENT (LOCA) MARGIN

SUMMARY

SAN ONOFRE NUCLEAR GENERATING STATION UNITS 2 AND 3 Larae Break LOCA Table 1 provides a time line of the items which could affect the Large Break LOCA peak cladding temperature (PCT) for this reporting period. The 10 CFR 50.46 PCT limit of 2,200°F was not exceeded.

Table I Limiting Large Break LOCA PCT Unit 2 Unit 3 Limiting Large Break LOCA PCT ir i End of 2004 2,170 °F 2,136 °F Changes in PCT during 2005 due to:

a ) Model changes or Model errors

• Cycle 13 0 OF 0 OF b ) Cycle Dependent Input Changes

• Cycle 13 0 OF 0 0F Limiting Large Break LOCA PCT End of 2005 2,170 OF 2,136 OF Page 1 of 4

The cumulative 10CFR50.46 model changes and model errors for the "Large Break LOCA June 1985 Evaluation Model" are shown in Table 2.

Table 2 Cumulative Large Break LOCA 10 CFR 50.46 Model Changes and Model Errors Y IA PCTI

• 11Unit 2TUnit3 Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors Priorto 2005 <I OF <I OF Changes in LBLOCA PCT due to Model Changes and Model Errors Discoveredin 2005

, Cycle 13 0 OF 0 OF Cumulative LBLOCA 10 CFR 50.46 Model Changes and Model Errors End of 2005 <I OF <I OF Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors.

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Small Break LOCA Table 3 provides a time line of the items which could affect the Small Break LOCA peak cladding temperature (PCT) for this reporting period. The SBLOCA 10 CFR 50.46 PCT limit of 2200 OF was not exceeded, and remained bounded by the LBLOCA.

Table 3 Limiting Small Break LOCA PCT IL___________________________________

ii ______________________________________

Unit 2 Unit 3 Limiting Small Break LOCA PCT End of 2004 1,903 OF 1,903 °F Changes in PCT during 2005 due to:

a) Model changes or Model errors

• Cycle 13 0 OF 0 OF b) Cycle Dependent Input Changes 0 Cycle 13 0 OF 0OF Limiting Small Break LOCA PCT End of 2005 1,903 OF 1,903 °F Page 3 of 4

The cumulative 10CFR50.46 model changes and model errors for the "Small Break LOCA S2M Evaluation Model" are shown in Table 4.

Table 4 Cumulative Small Break LOCA 10 CFR 50.46 Model Changes and Model Errors YI PCTIJ*

Unit 2 [Unit3 Cumulative SBLOCA 10 CFR 50.46 Model Changes and Model Errors Priorto 2005 19 OF 19 OF Changes in SBLOCA PCT due to Model Changes and Model Errors Discoveredin 2005

• Cycle 13 0°F 0°F Cumulative SBLOCA 10 CFR 50.46 Model Changes and Model Errors End of 2005 19 OF 19 OF

• Sum of the absolute magnitude of the 10 CFR 50.46 model changes and model errors.

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