RC-07-0081, ECCS Evaluation Model Revisions Annual Report

ECCS Evaluation Model Revisions Annual Report

ML071550417
Person / Time
Site:	Summer
Issue date:	06/01/2007
From:	Archie J South Carolina Electric & Gas Co
To:	Document Control Desk, NRC/NRR/ADRO
References
LTD 321, RC-07-0081
Download: ML071550417 (14)

Text

Jeffrey B. Archie Vice President, Nuclear Operations 803.345.4214 A SCANA COMPANY June 1, 2007 RC-07-0081 Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

VIRGIL C. SUMMER NUCLEAR STATION DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 ECCS EVALUATION MODEL REVISIONS ANNUAL REPORT

References:

1. Westinghouse Letter, LTR-LIS-07-149, "10 CFR 50.46 Annual Notification and Reporting for 2006 NOTRUMP-EM," (Non-Proprietary), dated March 7, 2007.

2. Westinghouse Letter, LTR-LIS-07-248, "10 CFR 50.46 Report for Best Estimate WCOBRA/TRAC Large Break LOCA EM General Code Maintenance,"

(Non-Proprietary), dated April 17, 2007.

3. Westinghouse Letter, LTR-LIS-06-662, "Transmittal of V. C. Summer SBLOCA PCT Rackup Sheets for HHSI Throttle Valve Replacement," (Non-Proprietary), dated November 10, 2006.

4. Westinghouse Letter, LTR-LIS-06-726, "Notification of Updated Virgil C. Summer LBLOCA PCT Summaries," (Non-Proprietary), dated December 1, 2006.

5. SCE&G Letter, RC-06-0202, J. B. Archie to NRC Document Control Desk, "ECCS Evaluation Model Revisions Report," dated November 15, 2006.

6. SCE&G Letter, RC-06-0205, J. B. Archie to NRC Document Control Desk, "ECCS Evaluation Model Revisions Report," dated December 4, 2006.

7. SCE&G Letter, RC-05-0097, J. B. Archie to NRC Document Control Desk, "License Amendment Request LAR 04-3385, Core Operating Limits Report - Reference for Best Estimate Loss of Coolant Accident (BELOCA)," dated June 30, 2005.

8. NRC Letter, R. E. Martin to J. B. Archie, "Virgil C. Summer Nuclear Station, Issuance of Amendment Regarding Best Estimate Loss-Of-Coolant Accident Analyses Methodology (TAC No. MC8262)," dated September 7, 2006.

Attached is the 2006 Emergency Core Cooling System (ECCS) Evaluation Model Revisions Annual Report for the Virgil C. Summer Nuclear Station (VCSNS). This report is being submitted pursuant to 10 CFR 50.46, which requires licensees to notify the NRC on at least an annual basis of corrections to or changes in the ECCS evaluation models.

SCE&G I Virgil C.Summer Nuclear Station

• P.O.Box 88. Jenkinsville, South Carolina 29065 .T (803) 345.5209. www.sceg.com A '0 2_

Document Control Desk LTD 321 RC-07-0081 Page 2 of 2 Summary sheets describing changes and enhancements to the ECCS evaluation models for 2006 are included in Attachment I. These summary sheets were addressed in Reference 1 for the Small Break Loss of Coolant Accident (SBLOCA) model and in Reference 2 for the Large Break Loss of Coolant Accident (LBLOCA) model.

Summary sheets describing changes to Peak Clad Temperature (PCT) are included in Attachment I1. All necessary revisions for any non-zero, non-discretionary, PCT change to Section C have been included. Any plant specific errors in the application of the model for 2006 are also provided in Section C with discussion enclosed or cited. These summary sheets were addressed in Reference 3 for the SBLOCA PCT and in Reference 4 for the LBLOCA PCT.

VCSNS previously submitted ECCS Evaluation Model Revisions reports for changes to the SBLOCA model that were initiated during 2006. The effect of using a finer break spectrum was addressed in Reference 5. The effect of replacing twelve existing high head safety injection valves was addressed in Reference 6.

It is important to note that VCSNS submitted License Amendment Request, LAR 04-3385, in Reference 7 for the use of the Westinghouse BELOCA methodology. The License Amendment request was granted in Reference 8. The LBLOCA summary sheets in Attachment II are now based on the BELOCA methodology.

If you have any questions, please call Mr. Bruce Thompson at (803) 931-5042.

MWD/JBA/dr Attachments c: K. B. Marsh S. A. Byrne N. S. Carns J. H. Hamilton R. J. White W. D. Travers R. E. Martin K. M. Sutton NRC Resident Inspector NSRC RTS (LTD 321)

File (818.02-17, RR 8375)

DMS (RC-07-0081)

Document Control Desk Attachment I LTD 321 RC-07-0081 Page 1 of 5 Attachment 1 10 CFR 50.46 Reporting Text

Document Control Desk Attachment I LTD 321 RC-07-0081 Page 2 of 5 Best Estimate Large Break - WCOBRA/TRAC Items

Document Control Desk Attachment I LTD 321 RC-07-0081 Page 3 of 5 GENERAL CODE MAINTENANCE (Discretionary Change - No PCT Impact)

Background

A number of coding changes were made as part of normal code maintenance. Examples include additional information in code outputs, improved automation in the ASTRUM codes, increased WCOBRA/TRAC code dimensions, and general code cleanup. All of these changes are considered to be discretionary changes in accordance with Section 4.1.1 of WCAP-1 3451.

Affected Evaluation Models 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model, Application to PWRs with Upper Plenum Injection 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect The nature of these changes leads to an estimated PCT impact of 0°F.

Document Control Desk Attachment I LTD 321 RC-07-0081 Page 4 of 5 Appendix K Small Break - NOTRUMP Related Items

Document Control Desk Attachment I LTD 321 RC-07-0081 Page 5 of 5 GENERAL CODE MAINTENANCE (Enhancements/Forward-Fit Discretionary Change)

Backqround Various changes in code input and output format have been made to enhance usability and help preclude errors in analyses. This includes both input changes (e.g., more relevant input variables defined and more common input values used as defaults) and input diagnostics designed to preclude unreasonable values from being used, as well as various changes to code output which have no effect on calculated results. In addition, various updates were made to eliminate inactive coding, improve active coding, and enhance commenting, both for enhanced usability and to facilitate code debugging when necessary. These changes represent Discretionary Changes that will be implemented on a forward-fit basis in accordance with Section 4.1.1 of WCAP-1 3451.

Affected Evaluation Models 1985 Westinghouse Appendix K Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect The nature of these changes leads to an estimated PCT impact of 0°F.

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 1 of 7 Attachment 2 PCT Rackup Sheets

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 2 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Best Estimate Large Break Plant Name: V. C. Summer Utility Name: South Carolina Electric & Gas Revision Date: 11/30/06 Composite Analysis Information EM: CQD (1996) Analysis Date: 2/3/03 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.7 Fuel: Vantage + SGTP (%): 10 Notes: Delta 75 Replacement Steam Generator Uprate Core Power 2900 MWt

( lad Temp (IF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1988 1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Backfit Through 2001 Reporting Year 0 2

2. Revised Blowdown Heatup Uncertainty Distribution 5 3 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. Fan Cooler Performance Increase 2 2 C. 2006 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT +PCT ASSESSMENTS I PCT = 1995

References:

1. WCAP-16043, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Virgil C. Summer Nuclear Station,"

June 2003.

2. CGE-03-12, "10 CFR 50.46 Annual Notification and Reporting for 2002," March 2003.

3. CGE-05-20, "10 CFR 50.46 Annual Notification and Reporting for 2004," April 2005.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 3 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Best Estimate Large Break Plant Name: V. C. Summer Utility Name: South Carolina Electric & Gas Revision Date: 11/30/06 Blowdown Analysis Information EM: CQD (1996) Analysis Date: 2/3/03 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.7 Fuel: Vantage + SGTP (%): 10 Notes: Delta 75 Replacement Steam Generator Uprate Core Power 2900 MWt

( lad Temp (IF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1860 1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Backfit Through 2001 Reporting Year 0 2

2. Revised Blowdown Heatup Uncertainty Distribution 49 3 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. Fan Cooler Performance Increase 0 2 C. 2006 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT +PCT ASSESSMENTS PCT = 1909

References:

1. WCAP-16043, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Virgil C. Summer Nuclear Station,"

June 2003.

2. CGE-03-12, "10 CFR 50.46 Annual Notification and Reporting for 2002," March 2003.

3. CGE-05-20, "10 CFR 50.46 Annual Notification and Reporting for 2004," April 2005.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 4 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Best Estimate Large Break Plant Name: V. C. Summer Utility Name: South Carolina Electric & Gas Revision Date: 11/30/06 Reflood 1 Analysis Information EM: CQD (1996) Analysis Date: 2/3/03 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.7 Fuel: Vantage + SGTP (%): 10 Notes: Delta 75 Replacement Steam Generator Uprate Core Power 2900 MWt Clad Temp (OF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1808 1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Backfit Through 2001 Reporting Year 0 2

2. Revised Blowdown Heatup Uncertainty Distribution 5 3 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. Fan Cooler Performance Increase 1 2 C. 2006 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT +PCT ASSESSMENTS  ?CT = 1814

References:

1. WCAP-16043, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Virgil C. Summer Nuclear Station,"

June 2003.

2. CGE-03-12, "10 CFR 50.46 Annual Notification and Reporting for 2002," March 2003.

3. CGE-05-20, "10 CFR 50.46 Annual Notification and Reporting for 2004," April 2005.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 5 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Best Estimate Large Break Plant Name: V. C. Summer Utility Name: South Carolina Electric & Gas Revision Date: 11/30/06 Reflood 2 Analysis Information EM: CQD (1996) Analysis Date: 2/3/03 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.7 Fuel: Vantage + SGTP (%): 10 Notes: Delta 75 Replacement Steam Generator Uprate Core Power 2900 MWt

( lad Temp (0F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1988 1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Backfit Through 2001 Reporting Year 0 2

2. Revised Blowdown Heatup Uncertainty Distribution 5 3 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. Fan Cooler Performance Increase 2 2 C. 2006 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER I None 0 LICENSING BASIS PCT +PCT ASSESSMENTS PCT = 1995

References:

1. WCAP-16043, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Virgil C. Summer Nuclear Station,"

June 2003.

2. CGE-03-12, "10 CFR 50.46 Annual Notification and Reporting for 2002," March 2003.

3. CGE-05-20, "10 CFR 50.46 Annual Notification and Reporting for 2004," April 2005.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 6 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: V. C. Summer Utility Name: South Carolina Electric & Gas Revision Date: 2/23/06 Analysis Information EM: NOTRUMP Analysis Date: 9/12/06 Limiting Break Size: 3 inch FQ: 2.4 FdH: 1.62 Fuel: Vantage + SGTP (%): 10 Notes:

Clad Temp (IF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1775 9 (a)

PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2005 ECCS MODEL ASSESSMENTS I. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS I PCT = 1775

References:

1. CGE-94-205, "South Carolina Electric and Gas Company, Virgil C. Summer Station, 10 CFR 50.46 Notification and Reporting Information," February 8, 1994.

2. CGE-94-228, "South Carolina Electric and Gas Company, Virgil C. Summer Station, SBLOCTA Axial Nodalization,"

October 27, 1994.

3. CGE-95-201, "South Carolina Electric and Gas Company, Virgil C. Summer Station, 10 CFR 50.46 Notification and Reporting Information," February 3, 1995.

4. CGE-96-202, "South Carolina Electric and Gas Company, Virgil C. Summer Station, 10 CFR 50.46 Annual Notification and Reporting," February 9, 1996.

5. CGE-96-213, "South Carolina Electric and Gas Company, Virgil C. Summer Station, 10 CFR 50.46 Small Break LOCA Notification and Reporting," July 8, 1996.

6. CGE-00-044, "South Carolina Electric and Gas Company, Virgil C. Summer Nuclear Station, 10 CFR 50.46 Appendix K (BART / BASH / NOTRUMP) Evaluation Model, Mid-Year Notification and Reporting for 2000," June 30, 2000.

7. CGE-03-80, "10 CFR 50.46 Mid-Year Notification and Reporting for 2003," January 2004.

8. LTR-LIS-06-344, "Transmittal of Updated V. C. Summer SBLOCA PCT Rackup Sheets," November 2006.

Document Control Desk Attachment II LTD 321 RC-07-0081 Page 7 of 7

9. LTR-Lis-06-662, "Transmittal of V. C. Summer SBLOCA PCT Rackup Sheets for HHSI Throttle Valve Replacement," November 2006.

Notes:

(a) The Rebaseline Analysis includes the impacts of the following model assessments:

1-LUCIFER Error Corrections (Ref. 1) 2-Effect of SI in Broken Loop (Ref. 1) 3-Effect of Improved Condensation Model (Ref. 1) 4-Axial Nodalization, RIP Model Revision and SBLOCA Error Corrections Analysis (Ref. 2) 5-Boiling Heat Transfer Error (Ref. 3) 6-Steam Line Isolation Logic Error (Ref. 3) 7-NOTRUMP Specific Enthalpy Error (Ref. 4) 8-SALIBRARY Double Precision Error (Ref. 4) 9-SBLOCA Fuel Rod Initialization Error (Ref. 5) 10-NOTRUMP Mixture Level Tracking / Region Depletion Errors (Ref. 6) 11 -NOTRUMP Bubble Rise / Drift Flux Model Inconsistency Corrections (Ref. 7) 12-Refined Break Spectrum (Ref. 8) 13-High Head Safety Injection (HHSI) flow increase (Ref. 9)