ML11159A210

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ECCS Evaluation Model Revisions Report
ML11159A210
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 06/06/2011
From: Gatlin T
South Carolina Electric & Gas Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML11159A210 (11)
v • d • e


Text

Thomas D. Gatlin Vice President,Nuclear Operations 803.345.4342 June 6, 2011 A SCANA COMPANY Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555

Dear Sir / Madam:

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 DOCKET NO. 50/395 OPERATING LICENSE NO. NPF-12 ECCS EVALUATION MODEL REVISIONS REPORT South Carolina Electric & Gas Company (SCE&G), hereby submits the 2010 Emergency Core Cooling System (ECCS) Evaluation Model Revisions Annual Report for 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.

Summary sheets describing changes and enhancements to the ECCS Evaluation Models for 2010 are included in Attachment I. Peak Clad Temperature (PCT) sheets are included in Attachment I1.

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

Very truly yours, Thomas D. Gatlin GAR/TDG/jw Attachments c: K. B. Marsh R. E. Martin S. A. Byrne NRC Resident Inspector J. B. Archie K. M. Sutton N. S. Cams NSRC J. H. Hamilton RTS (LTD 321, RR 8375)

R. J. White File (818.02-17)

W. M. Cherry PRSF (RC-11-0080)

V. M. McCree Virgil C.Summer Station. Post Office Box 88 . Jenkinsville, SC

  • 29065 *T (803) 345-5209

Document Control Desk Attachment I LTD 321 RC-1 1-0080 Page 1 of 3 Attachment I Changes and Enhancements to the ECCS Evaluation Models for 2010

Document Control Desk Attachment I LTD 321 RC-1 1-0080 Page 2 of 3 GENERAL CODE MAINTENANCE (Discretionary Change)

Background

Various changes have been made to enhance the usability of the codes and to help preclude errors in analyses. This includes items such as modifying input variable definitions, units, and defaults; improving the input diagnostic checks; enhancing the code output; optimizing active coding; and, eliminating inactive coding. These changes represent Discretionary Changes that will be implemented on a forward-fit basis in accordance with Section 4.1.1 of WCAP-13451,

'Westinghouse Methodology for Implementation of 10 CFR 50.46 Reporting."

Affected Evaluation Model 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model Estimated Effect The nature of these changes leads to an estimated PCT impact of 0°F.

PELLET CRACK AND DISH VOLUME CALCULATION (Non-Discretionary Change)

Background

Two errors were discovered in the calculation of the normalized pellet crack and dish volumes in the SBLOCTA code. First, an incorrect operator was used to select between two tables of normalized volume vs. linear heat generation rate. Second, the normalized volume at 18 kW/ft was incorrectly programmed in one of the tables as 1.58 instead of 1.59. These errors have been corrected in the SBLOCTA code and will be corrected (where applicable) in future versions of the BASH and LOCBART codes. These changes represent a closely-related group of Non-Discretionary Changes in accordance with Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect A combination of SBLOCTA sensitivity calculations and engineering judgment led to an estimated PCT effect of 0°F for existing Large and Small Break LOCA analysis results.

Document Control Desk Attachment I LTD 321 RC-1 1-0080 Page 3 of 3 TREATMENT OF VESSEL AVERAGE TEMPERATURE UNCERTAINTY (Non-Discretionary Change)

Background

Historically, the overall vessel average temperature uncertainty calculated by Westinghouse considered only "-"instrument uncertainties, corresponding to the indicated temperature being lower than the actual temperature. This uncertainty was then applied as a "+/-" uncertainty in some LOCA analyses, rather than using specific "+" and "-"uncertainties. This discrepancy has been evaluated for impact on existing Large and Small Break LOCA analysis results, and its resolution represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model Estimated Effect This issue was judged to have a negligible impact on existing Large and Small Break LOCA analysis results, leading to an estimated PCT impact of 0°F.

Document Control Desk Attachment II LTD 321 RC-1 1-0080 Page 1 of 7 Attachment II PCT Rackup Sheets

Document Control Desk Attachment II LTD 321 RC-1 1-0080 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 Company Revision Date: 1/14/11 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 Clad Temp (OF) 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
3. Transverse Momentum Cells for Zero Cross-flow -14 4 Boundary Condition Error B. PLANNED PLANT MODIFICATION EVALUATIONS
1. Fan Cooler Performance Increase 2 2
2. Upflow Conversion Evaluation -29 4 C. 2010 ECCS MODEL ASSESSMENTS
1. None 0 D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1952

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.
4. LTR-LIS-08-578, Revision 2, "Large Break LOCA Evaluation for V. C. Summer (CGE)

Upflow Conversion and Assessment of Transverse Momentum Cells for Zero Cross-flow Boundary Condition Error," January 2009.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-1 1-0080 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 Company Revision Date: 1/14/11 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 Clad Temp (*F) 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
3. Transverse Momentum Cells for Zero Cross-flow Boundary Condition 1 4 B. PLANNED PLANT MODIFICATION EVALUATIONS
1. Fan Cooler Performance Increase 0 2
2. Upflow Conversion Evaluation -7 4 C. 2010 ECCS MODEL ASSESSMENTS
1. None D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1903

References:

1. WCAP-1 6043, "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.
4. LTR-LIS-08-578, Revision 2, "Large Break LOCA Evaluation for V. C. Summer (CGE)

Upflow Conversion and Assessment of Transverse Momentum Cells for Zero Cross-flow Boundary Condition Error," January 2009.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-1 1-0080 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 Company Revision Date: 1/14/11 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
3. Transverse Momentum Cells for Zero Cross-flow Boundary Condition -9 4 B. PLANNED PLANT MODIFICATION EVALUATIONS
1. Fan Cooler Performance Increase 1 2
2. Upflow Conversion Evaluation -44 4 C. 2010 ECCS MODEL ASSESSMENTS
1. None D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1761

References:

1. WCAP-1 6043, "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.
4. LTR-LIS-08-578, Revision 2, "Large Break LOCA Evaluation for V. C. Summer (CGE)

Upflow Conversion and Assessment of Transverse Momentum Cells for Zero Cross-flow Boundary Condition Error," January 2009.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-1 1-0080 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 Company Revision Date: 1/14/11 Reflood 2 Analysis Information EM: CQD (1996) Analysis Date: 2/1/03 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 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
3. Transverse Momentum Cells for Zero Cross-flow Boundary Condition Error -14 4 B. PLANNED PLANT MODIFICATION EVALUATIONS
1. Fan Cooler Performance Increase 2 2
2. Upflow Conversion Evaluation -29 4 C. 2010 ECCS MODEL ASSESSMENTS
1. None D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT= 1952

References:

1. WCAP-1 6043, "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.
4. LTR-LIS-08-578, Revision 2, "Large Break LOCA Evaluation for V. C. Summer (CGE)

Upflow Conversion and Assessment of Transverse Momentum Cells for Zero Cross-flow Boundary Condition Error," January 2009.

Notes:

None

Document Control Desk Attachment II LTD 321 RC-1 1-0080 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 Company Revision Date: 1/14/11 Analysis Information EM: NOTRUMP Analysis Date: 9/12/06 Limiting Break Size: 3 Inch FQ: 2.45 FdH: 1.62 Fuel: Vantage + SGTP (%): 10 Notes:

Clad Temp (°F) 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. Upflow Conversion 148 10,11 C. 2010 ECCS MODEL ASSESSMENTS
1. None 0 D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1923

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.

Document Control Desk Attachment II LTD 321 RC-1 1-0080 Page 7 of 7

8. LTR-LIS-06-344, "Transmittal of Updated V. C. Summer SBLOCA PCT Rackup Sheets," November 2006.
9. LTR-LIS-06-662, 'Transmittal of V. C. Summer SBLOCTA PCT Rackup Sheets for HHSI Throttle Valve Replacement," November 2006.
10. WCAP-16980-P, Revision 1, "Reactor Internals Upflow Conversion Program Engineering Report V. C. Summer Nuclear Station Unit 1," December 2008.
11. LTR-LIS-09-18, "10 CFR 50.46 Report for the V. C. Summer (CGE) Upflow Conversion Program Small Break LOCA Evaluation," January 2009.

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 SBLOCTA 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-SBLOCTA 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)

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