ML021550310

Submittal of Emergency Core Cooling System Codes and Methods Report

ML021550310
Person / Time
Site:	Calvert Cliffs
Issue date:	05/29/2002
From:	Cruse C Constellation Nuclear
To:	Office of Nuclear Reactor Regulation
References
Download: ML021550310 (19)

Text

Charles H. Cruse 1650 Calvert Cliffs Parkway Vice President Lusby, Maryland 20657 Nuclear Energy 410 495-4455 0 Nuclear Constellation Calvert Cliffs Nuclear Power Plant A Member of the Constellation Energy Group May 29, 2002 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos. 1 & 2; Docket Nos. 50-3 17 & 50-3 18 Submittal of Emergency Core Cooling System Codes and Methods Report As required by 10 CFR 50.46(a)(3)(ii), the Emergency Core Cooling System Codes and Methods Report is provided in Attachment (1). The annual report provided in Attachment (1) corrects the applicable time period for the report in the Abstract to be calendar year 2001, corrects the information for Palisades in Appendix D, and contains minor editorial changes to clarify the report. Only Appendix B of the Annual Report, which is pertinent to Calvert Cliffs Nuclear Power Plant, is included in our submittal. In addition to the final report, a summary of computer code errors resolved in calendar year 2001 that do not impact the peak cladding temperature or other Emergency Core Cooling System Acceptance Criteria is provided in Attachment (2).

Should you have questions regarding this matter, we will be pleased to discuss them with you.

Very truly yours, CHC/DJM/bjd Attachments (1) CENPD-279, Supplement 13, Revision 1, "Annual Report on Combustion Engineering ECCS Performance Evaluation Models for PWRs," Westinghouse Electric Company LLC, April 2002 (2) Errors in Codes Used for PWR ECCS Performance Analysis cc: D. M. Skay, NRC (Without Attachments)

R. S. Fleishman, Esquire H. J. Miller, NRC J. E. Silberg, Esquire Resident Inspector, NRC Director, Project Directorate I-1, NRC R. I. McLean, DNR

ATTACHMENT (1)

CENPD-279, Supplement 13, Revision 1 "ANNUAL REPORT ON COMBUSTION ENGINEERING ECCS PERFORMANCE EVALUATION MODELS for PWRs,"

Westinghouse Electric Company LLC, April 2002 Calvert Cliffs Nuclear Power Plant, Inc.

May 29,2002

CENPD-279 Supplement 13, Rev. 1 ANNUAL REPORT ON COMBUSTION ENGINEERING ECCS PERFORMANCE EVALUATION MODELS for PWRs April 2002

§ Copyright 2002, Westinghouse Electric Company LLC. All rights reserved.

Westinghouse Electric Company LLC

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 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.

Westinghouse Electric Company LLC

ABSTRACT This report describes changes and errors in the ECCS performance analysis models for PWRs developed by Combustion Engineering in calendar year (CY) 2001 per the requirements of IOCFR50.46. For this reporting period, there were four changes and one error in the evaluation models or application of the models that affect the cladding temperature calculation.

1. The 1999 Evaluation Model (EM) for LBLOCA was accepted by the NRC at the end of CY 2000 and introduced for licensing analyses in CY year 2001. Introduction of the new models and methodology for the 1999 EM has no effect on ECCS performance analysis results for the other LBLOCA and SBLOCA evaluation models.

2. The hot rod heat-up codes HCROSS, PARCH, and STRIKIN-II were combined into an Integrated STRIKIN-II code to support the 1999 EM. This has no effect on the PCT for the other LBLOCA and SBLOCA evaluation models.

3. Properties for ZIRLOTM cladding were introduced into the computer codes used for the 1999 EM for LBLOCA and the S2M for SBLOCA and NRC accepted in CY 2001. This has no effect on the PCT for licensing analyses with Zircaloy-4 cladding.

4. The computer system state was changed for the ECCS performance analysis computer codes. The changes include use of a new version of the FORTRAN 77 compiler, new compiler and loader options for codes that were compiled in calendar year 2001 (CEFLASH-4A, COMPERC-ll, HCROSS, PARCH, STRIKIN-il, COMZIRC, CEFLASH-4AS and some of the related utility codes), and operation under a new version of the computer operating system. These changes had a negligible effect on the PCT (< 0. VF) for each of the evaluation models - 1985 EM and 1999 EM for LBLOCA and the SIM and S2M for SBLOCA.

5. An error in the CEFLASH-4AS code for SBLOCA blowdown analysis was found and corrected. The effect on the SBLOCA PCT is different for each plant or related set of plants. Plant specific results are given in Appendices A-G.

The sum of the absolute magnitude of the peak cladding temperature (PCT) changes for the large break LOCA June 1985 EM from all reports to date continues to be less than 1°F excluding plant specific effects. The total effect relative to the 50°F definition of a significant change in PCT is the sum of <I°F and plant specific effects, if any, described in Appendices A-G. The accumulated change in cladding temperature for the large break LOCA 1999 EM is 00 F. The sum of the absolute magnitude of the maximum cladding temperature changes for the small break LOCA SIM evaluation model from all reports to date is < 3F plus the plant specific results in Appendices A-G. The accumulated change in cladding temperature for the small break LOCA S2M evaluation model is limited to plant specific effects given in Appendices A-G. No change occurred in the PCT due to post-LOCA long term cooling issues.

Revision 1 corrects the applicable time period for the report in the Abstract to be CY 2001, corrects the SBLOCA results for Palisades in Appendix D, and makes minor editorial changes.

Westinghouse Electric Company LLC i

TABLE OF CONTENTS Section Title PagE

1.0 INTRODUCTION

1 2.0 COMBUSTION ENGINEERING ECCS EVALUATION MODELS AND CODES 3 3.0 EVALUATION MODEL CHANGES AND ERROR CORRECTIONS 4 3.1 1999 Evaluation Model for LBLOCA 4 3.2 Integrated STRIKIN-i1 Rod Temperature Code 4 3.3 ZIRLO TM Cladding Properties 4 3.4 Change in Computer System State 5 3.5 Code Error in CEFLASH-4AS 6

4.0 CONCLUSION

S 7

5.0 REFERENCES

8 APPENDICES (Plant Specific Considerations)

A. ARIZONA PUBLIC SERVICE COMPANY (PVNGS Units 1-3)

B. CALVERT CLIFFS NUCLEAR POWER PLANT INCORPORATED (Calvert Cliffs Units I & 2)

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

D. CONSUMER ENERGY COMPANY (Palisades)

E. ENTERGY OPERATIONS, INCORPORATED

1. Arkansas Nuclear One Unit 2

2. Waterford Unit 3 F. FLORIDA POWER AND LIGHT COMPANY (St. Lucie Unit 2)

G. DOMINION RESOURCES (Millstone Unit 2)

Westinghouse Electric Company LLC ii

1.0 INTRODUCTION

This report addresses the NRC requirement to report changes or 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 50T.

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 10CFR50.46 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 LOCFR50.46 requirements.

Westinghouse Electric Company LLC I

This report documents all 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 provided to satisfy the reporting requirements of the second item above. Reports for earlier years are given in References 2-14.

Westinghouse Electric Company LLC 2

2.0 COMBUSTION ENGINEERING ECCS EVALUATION MODELS AND CODES Five evaluation models (EM) for ECCS performance analysis of PWRs developed by Combustion Engineering 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 June 1985 EM and the 1999 EM accepted by the NRC in 2000. There are two evaluation models for small break LOCA (SBLOCA): the SBLOCA Evaluation Model (SIM) and the S2M SBLOCA EM accepted by the NRC in 1997. Post-LOCA long term cooling (LTC) analyses are performed with the LTC evaluation model.

Several digital computer codes developed by Combustion Engineering 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-ll, HCROSS, PARCH, STRIKIN-fi, and COMZIRC. CEFLASH-4AS is used in conjunction with COMPERC-II, STRIKIN-II, and PARCH for SBLOCA calculations. The codes for post-LOCA LTC analysis are BORON, CEPAC, NATFLOW, and CELDA.

Westinghouse Electric Company LLC 3

3.0 EVALUATION MODEL CHANGES AND ERROR CORRECTIONS This section discusses all error corrections and model changes to the ECCS performance evaluation models for PWRs developed by Combustion Engineering that may affect the calculated PCT.

3.1 1999 Evaluation Model for LBLOCA A revised Appendix K model for LBLOCA called the 1999 EM was NRC accepted at the end of calendar year 2000 per Reference 15 and introduced for licensing analysis in calendar year 2001.

Implementation of the 1999 EM methodology included changes to the following codes:

CEFLASH-4A, COMPERC-II, HCROSS, PARCH, STRIKIN-il, and COMZIRC as well as some supporting utility codes. The new models and methodology for the 1999 EM are added as an option to the existing codes that support the 1985 EM for LBLOCA and the SBLOCA models.

These changes have no effect on results produced for the June 1985 EM, SIM or S2M.

3.2 Integrated STRIKIN-Il Rod Temperature Code The codes used for rod temperature calculations for all LBLOCA and SBLOCA methodologies (HCROSS, PARCH, and STRIKIN-il) have been integrated into a single code to accommodate data flow requirements between them for the 1999 EM methodology. Each code is incorporated as a module that can perform all of its previous functions as a stand-alone code or can be used in a linked mode for the 1999 EM. The combined tool is called the Integrated STRIKIN-I1 code. It supports the 1985 and 1999 EM for LBLOCA licensing analyses, the SIM and S2M for SBLOCA licensing analyses, and a realistic evaluation model used for non-licensing calculations. Testing has demonstrated that all previous functions of the stand-alone codes are supported and the modules of the Integrated STRIKIN-I1 code give the same results as the stand alone codes.

3.3 ZIPLO TM Cladding Properties Physical properties for ZIRLOTM cladding were added to the following codes for use in the 1999 EM and the S2M: CEFLASH-4A, COMPERC-ll, PARCH, STRIKIN-Il, COMZIRC, and CEFLASH-4AS. They are a new option in addition to the Zircaloy-4 cladding properties that continue to be supported in these codes. These changes have no effect on results produced for Westinghouse Electric Company LLC 4

Zircaloy-4 cladding. NRC acceptance of the models and methodology for ZIRLO M T

cladding is documented in Reference 16.

3.4 Change in Computer System State Changes to the version of the FORTRAN 77 compiler, the operating system (OS), and the computer hardware are accommodated as part of the code changes summarized in Sections 3.1, 3.2, and 3.3. In addition, the coding for CEFLASH-4A, COMPERC-ll, HCROSS, PARCH, STRIKIN-iI, COMZIRC, CEFLASH-4AS and some of the related utility codes were revised to address three issues related to portability and stability of the codes. The codes were tested for occurrence of out-of-range subscripts and corrected as needed. The compilation options were changed to stop execution when a floating-point arithmetic exception occurs and coding was revised as necessary to avoid floating-point arithmetic exceptions. Finally, the linking options for the loader were changed to statically link the FORTRAN libraries to the executables which makes the coding insensitive to changes in the OS version (changes in the FORTRAN library routines).

The revised codes were tested to evaluate the effect of these changes and introduction of the new models described in Sections 3.1, 3.2, and 3.3 on the existing methodologies for LBLOCA and SBLOCA. The effect of correcting out-of-range subscripts for the SBLOCA PCT is documented on a plant specific basis as discussed in Section 3.5 and Appendices A-G. The effect of the other changes on PCT for SBLOCA is discussed here. Test results for PCT are summarized in the table below.

Model PCT Change (OF) 1985 EM for LBLOCA None 1999 EM for LBLOCA < 0.1 SIM for SBLOCA < 0.1 S2M for SBLOCA < 0.1 The PCT for the 1985 EM is not affected by the changes in the computer system state described above. The PCT effect for the 1999 EM is less that 0. I°F which is negligible. The PCT effects for the SIM and S2M are also less than 0.1°F. Their effect is included in the plant specific SBLOCA results discussed in Appendices A-G.

Westinghouse Electric Company LLC 5

3.5 Code Error in CEFLASH-4AS The testing for out-of-range subscripts described in Section 3.4 identified one important subscripting error in CEFLASH-4AS that affects the leak flow rate and PCT results for both the SIM and S2M SBLOCA. A couple of additional subscripting errors had a minor effect (< iF) on the PCT results. Two additional code problems were discovered during the code testing process with the new compiler options enabled that stop the code from completing the transient calculation. These problems were addressed and the effects of the necessary coding changes were evaluated. Only the out-of range subscript error for the leak flow rate affected the PCT.

Addressing the other problems allowed CEFLASH-4AS to run to the end of the transient but had no PCT consequences. The SBLOCA PCT effect of the out-of-range subscripts is plant specific and is discussed in Appendices A-G.

Westinghouse Electric Company LLC 6

4.0 CONCLUSION

S There were four changes to and one error in the ECCS evaluation models for PWRs developed by Combustion Engineering for LBLOCA, SBLOCA, or post-LOCA long term cooling in CY 2001. Two of the changes are implementation of the 1999 EM for LBLOCA and incorporation of ZIRLOTM properties in the LBLOCA and SBLOCA codes which were accepted by the NRC per References 15 and 16; therefore, they have no effect on the results for this report. The third change is integration of PARCH and HCROSS as modules of the Integrated STRIKIN-Il code.

This has no effect on results for the 1985 EM for LBLOCA or the SBLOCA SIM and S2M. It was done to support creation of the 1999 EM. The fourth change is installation of the computer codes on a new computer system state including coding changes to address out-of-range subscripts and floating point arithmetic exceptions. This has a negligible effect on the PCT

-results except as discussed below for SBLOCA. The sum of the absolute magnitude of the changes in PCT calculated using the June 1985 EM for LBLOCA, including those from previous annual reports, References 2-14, remains less than IF relative to the 50°F criterion for a significant change in PCT. The total 1985 EM LBLOCA impact on PCT for a given plant is

<I°F plus the plant specific effects, if any, described in Appendices A through G. There is no accumulated PCT error for the 1999 EM for LBLOCA.

Out-of-range subscripts in CEFLASH-4AS affected the PCT results for both SLM and S2M SBLOCA evaluation modes in a plant specific way as discussed in Appendices A through G. In addition, there is an effect on maximum cladding temperature for the SBLOCA SIM (due to the change in application of the SBLOCA SIM described in Reference 11) that is less than 3°F.

There is no previous accumulated change in cladding temperature for the S2M. Plant specific SBLOCA considerations for each plant are discussed in Appendices A through G.

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

Westinghouse Electric Company LLC 7

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," CENPD-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 l1OCFR50.46," 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, March, 1997.

11. "Annual Report on ABB CE ECCS Performance Evaluation Models," CENPD-279, Supplement 9, February, 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. "Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model,"

CENPD-132, Supplement 4-P-A, March 2001.

Westinghouse Electric Company LLC 8

M Cladding Material in CE Nuclear Power Fuel Assembly

16. "Implementation of ZIRLOQ Designs," CENPD-404-P-A, Revision 0, November, 2001.

Westinghouse Electric Company LLC 9

APPENDIX B CALVERT CLIFFS NUCLEAR POWER PLANT INCORPORATED Plant Specific Considerations for Calvert Cliffs Units 1 and 2 Introduction As described in Section 3.5, an error in the leak flow rate for the CEFLASH-4AS code due to out-of-range subscripts produced a plant specific impact on cladding temperature for SBLOCA.

A 10 CFR 21 evaluation was performed. Based on the results of sensitivity analyses, as well as known results from improved Appendix K and best estimate SBLOCA methodologies for CENP plant designs, it was determined that the error was not capable of creating a substantial safety hazard, as defined in 10 CFR 21 (Reference 1); therefore, it was not reportable.

Effect Plant specific sensitivity studies for Calvert Cliffs Units 1 and 2 were transmitted to Calvert Cliffs Nuclear Power Plant Company by Reference 2. The results of those sensitivity studies are summarized in the table below.

CORRECTED SBLOCA RESULTS FOR CEFLASH-4AS COMPUTER CODE ERROR PEAK CLAD MAXIMUM CORE-WIDE RESULT / PARAMETER TEMPERATURE, CLADDING CLADDING OXIDATION, % OXIDATION, %

CORRECTED CODE VERSION LIMITING CASE 1914 4.04 0.59 AOR BENCHMARK UNCORRECTED CODE 1871 3.27 0.48 VERSION LIMITING CASE*

DIFFERENTIAL IMPACT +43 +0.77 +0.11 Note that the "benchmark" AOR case PCT and the previously reported licensing case AOR PCT may or may not be the same depending on the vintage of the licensing case AOR.

Westinghouse Electric Company LLC B.1

The analysis underlying these results has been independently reviewed pursuant to CE Nuclear Power LLC's (now WEC) quality procedures and the verification status is categorized as "COMPLETE".

Conclusion The effect of the CEFLASH-4AS code error on the SBLOCA PCT is 430 F based on calculations for 2500 plugged tubes in each steam generator with the SIM. This analysis predates the change in SLM methodology to automate data transfer between CEFLASH-4AS and PARCH; consequently, there is no accumulated PCT difference and the total effect is 43TF. WEC believes that the impact of this error does not exceed the 50 0 F reporting criterion for a significant error.

References:

1. NSAL-01-002, "Small Break LOCA ECCS Performance Computer Code Error," C. M.

Molnar, et al., April 4, 2001.

2. Letter from I. Pucak (WEC) to G. Pavis (CCNPPI), CC-FO-2001-0032, "CEFLASH-4AS Code Error," April 30, 2001.

Westinghouse Electric Company LLC B.2

ATTACHMENT (2)

ERRORS IN CODES USED FOR PWR ECCS PERFORMANCE ANALYSIS Calvert Cliffs Nuclear Power Plant, Inc.

May 29,2002

Attachment 2 Problems in Codes Used for PWR ECCS Performance Analysis The code problems described here were identified in calendar year 2001 during code maintenance activities done per the provisions of the computer software section, QP 3.13, of the WEC QMS. They have no impact on the peak cladding temperature (PCT); therefore, they are not reported under the provisions of 10CFR50.46. This information is provided for completeness in the reporting process.

PARCH Module of Integrated STRIKIN-II Code The PARCH module of the Integrated STRIKIN-11 code is part of the PWR ECCS analysis evaluation models developed by Combustion Engineering. It calculates steam-cooling heat transfer coefficients for the LBLOCA 1985 and 1999 evaluation models (85EM and 99EM),

performs SBLOCA rod temperature calculations for the SBLOCA S 1M and S2M and is part of the non-licensed realistic evaluation model (REM) for SBLOCA.

Preliminary use of the Integrated STRIKIN-II code revealed three problems with the PARCH module for LBLOCA analyses - power shape renormalization, temperature initialization of the rupture node at the one-inch per second time for steam heat transfer, and the 99EM automatic nodal mapping of steam cooling heat transfer data for rupture in STRIKIN-il Node 19. PARCH was modified to ensure that the power shape is renormalized to exactly 1.0 instead of a total slightly different than 1.0 when the 20 node axial shape is linearly interpolated to obtain values for 50 axial nodes. This affects both the 85EM and 99EM. Initialization of fuel and cladding temperature at the one-inch per second time was changed to improve consistency of the STRIKIN-II and PARCH temperatures for the 99EM. Mapping of the steam heat transfer coefficient node number interface between PARCH and STRIKIN-II for rupture in STRIKIN-11 Node 19 was corrected. Finally, an error message is provided and the calculation is stopped when the cladding temperature is increasing in an unbounded manner above 2200'F due to heat from the zirconium water reaction.

The impact of these changes on the 10CFR50.46 acceptance criteria results including PCT is negligible for LBLOCA based on testing of the PARCH module for 85EM and 99EM applications. SBLOCA results are not affected by these changes.