ML12160A354

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ECCS Evaluation Model Revisions Report
ML12160A354
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 06/06/2012
From: Gatlin T
South Carolina Electric & Gas Co, SCANA Corp
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12160A354 (13)
v • d • e


Text

Thomas D. Gatlin Vice President, NuclearOperations 803.345.4342 A SCANA COMPANY June 6,2012

\

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), acting for itself and as agent for South Carolina Public Service Authority, hereby submits the 2011 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 2011 are included in Attachment I. Peak Clad Temperature (PCT) sheets are included in Attachment II.

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. Carns NSRC J. H. Hamilton RTS (LTD 321, RR 8375)

R. J. White File (818.02-17)

W. M. Cherry PRSF (RC-12-0089)

V. M. McCree Virgil C.Summer Station

  • Post Office Box 88
  • Jenkinsville, SC -29065 . F(803) 345-5209 , , &, j'

Document Control Desk Attachment I LTD 321 RC-12-0089 Page 1 of 5 Attachment I Changes and Enhancements to the ECCS Evaluation Models for 2011

Document Control Desk Attachment I LTD 321 RC-12-0089 Page 2 of 5 GENERAL CODE MAINTENANCE (Discretionary Change)

Background

Various changes have been made to enhance the usability of codes and to streamline future analyses. Examples of these changes include 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-1 3451.

Affected Evaluation Model(s) 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.

Document Control Desk Attachment I LTD 321 RC-12-0089 Page 3 of 5 RADIATION HEAT TRANSFER LOGIC (Non-Discretionary Change)

Background

Two errors were discovered in the calculation of the radiation heat transfer coefficient in the SBLOCTA computer code. First, existing diagnostics did not preclude non-physical negative or large (negative or positive) radiation heat transfer coefficients from being calculated. These calculations occurred when the vapor temperature exceeded the cladding surface temperature or when the predicted temperature difference was less than 1 degree. Second, a temperature term incorrectly used degrees Fahrenheit instead of Rankine. These errors have been corrected in the SBLOCTA code and 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 Small Break LOCA analysis results.

Document Control Desk Attachment I LTD 321 RC-1 2-0089 Page 4 of 5 MAXIMUM FUEL ROD TIME STEP LOGIC (Non-Discretionary Change)

Background

An error was discovered in the SBLOCTA code that allowed the fuel rod time step to exceed the specified maximum allowable time step. The time step logic has been corrected in the SBLOCTA code. This change 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 Estimated Effect A combination of SBLOCTA sensitivity calculations and engineering judgment led to an estimated PCT effect of 00 F for existing Small Break LOCA analysis results.

Document Control Desk Attachment I LTD 321 RC-12-0089 Page 5 of 5 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.

Affected Evaluation Model(s) 1985 Westinghouse 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-12-0089 Page 1 of 7 Attachment II PCT Rackup Sheets I

Document Control Desk Attachment II LTD 321 RC-12-0089 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: 2/20/2012 Composite Analysis Information EM: CQD (1996) Analysis Date: 2/3/2003 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 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. 2011 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 2-0089 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: 2/20/2012 Blo wdown Analysis Information EM: CQD (1996) Analysis Date: 2/3/2003 Limiting Break Size: Guiillotine 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. 2011 ECCS MODEL ASSESSMENTS
1. None 0 D. OTHER
1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1903

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-12-0089 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: 2/20/2012 Reflood 1 Analysis Information EM: CQD (1996) Analysis Date: 2/3/2003 Limiting Break Size: G uillotine 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 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. 2011 ECCS MODEL ASSESSMENTS
1. None 0 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-12-0089 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: 2/20/2012 Re flood 2 Analysis Information EM: CQD (1996) Analysis Date: 2/3/2003 Limiting Break Size: Gui Ilotine 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 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. 2011 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-12-0089 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: 2/20/2012 Analysis Information EM: NOTRUMP Analysis Date: 9/12/2006 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. 2011 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-12-0089 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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