CP-201200315, Annual Report of Changes in Peak Cladding Temperature

Annual Report of Changes in Peak Cladding Temperature

ML12128A055
Person / Time
Site:	Comanche Peak
Issue date:	04/17/2012
From:	Flores R Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201200315, TXX-12053
Download: ML12128A055 (12)

Text

Rafael Flores Luminant Power Senior Vice President P 0 Box 1002 MIN & Chief Nuclear Officer 6322 North FM 56 rafael.flores@Luminant.com Glen Rose, TX 76043 Lum inant T254 897 5550 C 817 559 0403 F 254 897 6652 CP-201200315 Ref. # 10CFR50.46 Log # TXX-12053 April 17, 2012 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT (CPNPP)

DOCKET NOS. 50-445 AND 50-446 ANNUAL REPORT OF CHANGES IN PEAK CLADDING TEMPERATURE

Dear Sir or Madam:

Pursuant to 10CFR50.46(a)(3)(ii), Luminant Generation Company LLC (Luminant Power) hereby submits the attached peak cladding temperatures (PCT) for Comanche Peak Nuclear Power Plant (CPNPP), Units 1 and 2. The Large-Break Loss-of-Coolant-Accident and Small-Break Loss-of-Coolant Accident analysis for Units I and 2 were performed for Luminant Power with the approved Westinghouse methodologies listed in Technical Specification 5.6.5.

Luminant Power has reviewed the notification of 10CFR50.46 reporting information pertaining to the ECCS Evaluation Model changes that were implemented by Westinghouse for 2011. The review concludes that the effect of changes to, or errors in, the Evaluation Models on the limiting transient PCT is not significant for 2011.

Therefore, the report of the ECCS Evaluation Model changes is provided on an annual basis.

Attachment I provides an assessment of the specific changes and enhancements to the Westinghouse Evaluation Models for 2011. These model changes and enhancements do not have impacts on the PCT.

Attachment 2 provides the calculated Large-Break Loss-of-Coolant Accident (LOCA) and Small Break LOCA PCT margin allocations in effect for the 2011 Comanche Peak Units 1 and 2 Evaluation Models.

There were no changes, error corrections, or enhancements to the 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP. The PCT values determined in the Large Break LOCA analysis of record, combined with all of the PCT allocations, remain well below the 10CFR50.46 regulatory limit of 2200 degrees Fahrenheit. Therefore, CPNPP Units 1 and 2 are in compliance with 10CFR50.46 requirements and no reanalysis or other action is required.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance CO0 Callaway - Comanche Peak - Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project

• Wolf Creek

U. S. Nuclear Regulatory Commission TXX-12053 Page 2 April 17, 2012 This communication contains no new licensing basis commitments regarding CPNPP Units 1 and 2.

Should you have any questions, please contact Mr. J. D. Seawright at (254) 897-0140.

Sincerely, Luminant Generation Company LLC Rafael Flores By:

. Fred W.YMadden Director, Oversight & Regulatory Affairs Attachments - 1. Assessment of specific changes and enhancements to the Westinghouse Evaluation Models for 2011

2. CPNPP Units 1 and 2 Peak Cladding Temperatures c- E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak of TXX-12053 Page 1 of6 GENERAL CODE MAINTENANCE

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-13451.

Affected Evaluation Model(s) 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 00 F.

of TXX-12053 Page 2 of 6 RADIATION HEAT TRANSFER LOGIC

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 I 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.

of TXX-12053 Page 3 of 6 MAXIMUM FUEL ROD TIME STEP LOGIC

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 0°F for existing Small Break LOCA analysis results.

of TXX-12053 Page 4 of 6 GENERAL CODE MAINTENANCE

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.

of TXX-12053 Page 5 of 6 COMANCHE PEAK UNIT 2 CYCLE 13 PBOT/PMID VIOLATION

Background

The Comanche Peak Unit 2 Cycle 13 reload core design resulted in several violations of the PBOT/PMID box used in the Large Break LOCA Analysis. These violations were evaluated for Comanche Peak Unit 2 Cycle 13 operation. This change represents a Discretionary Change in accordance with Section 4.1.1 of WCAP-13451.

Affected Evaluation Model(s) 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect The impact of the PBOT/PMID violation for Comanche Peak Unit 2 Cycle 13 was determined via a plant specific evaluation to be O°F.

of TXX-12053 Page 6 of 6 COMANCHE PEAK UNIT 1 CYCLE 16 PBOT/PMID VIOLATION

Background

The Comanche Peak Unit I Cycle 16 reload core design resulted in several violations of the PBOT/PMID box used in the Large Break LOCA Analysis. These violations were evaluated for Comanche Peak Unit 1 Cycle 16 operation. This change represents a Discretionary Change in accordance with Section 4.1.1 of WCAP-13451.

Affected Evaluation Model(s) 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect The impact of the PBOT/PMID violation for Comanche Peak Unit 1 Cycle 16 was determined via a plant specific evaluation to be 00 F.

to TXX-12053 Page 1 of 4 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit I Utility Name: Luminant Revision Date: 2/22/2012 Analysis Information EM: ASTRUM (2004) Analysis Date: 7/27/2007 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.6 Fuel: OFA SGTP(%): 10 Notes:

Clad Temp(°F) Ref. Notes LICENSIS BASIS Analysis-Of-Record PCT 1492 I PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

2. None 0 C. 2011 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1492

References:

I. WCAP-16762-P, Revision 1, "Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Comanche Peak Nuclear Power Plant Unit 1Using the ASTRUM Methodology," March 2009.

Notes:

None to TXX-12053 Page 2 of 4 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit I Utility Name: Luminant Revision Date: 2/22/2012 Analysis Information EM: NOTRUMP Analysis Date: 6/8/2007 Limiting Break Size: 4 inch FQ: 2.5 FdH: 1.6 Fuel: OFA SGTP(%): 10 Notes:

Clad Temp( 0°) Ref. Notes LICENSIS BASIS Analysis-Of-Record PCT 1013 I PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2011 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1013

References:

1. WCAP-16840-P, "Comanche Peak Nuclear Power Plant Stretch Power Uprate Licensing Report," August 2007. (Results are included in TXX-07107, "Comanche Peak Steam Electric Station (CPSES), Docket Nos. 50-445 and 50-446, Submittal of the CPSES Units I and 2 Large and Small Break LOCA Analyses," July 31, 2007.)

Notes:

None to TXX-12053 Page 3 of 4 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/22/2012 Analysis Information EM: ASTRUM (2004) Analysis Date: 7/27/2007 Limiting Break Size: Guillotine FQ: 2.5 FdH: 1.6 Fuel: OFA SGTP(%): 10 Notes:

Clad Temp(°F) Ref Notes LICENSIS BASIS Analysis-Of-Record PCT 1632 1 PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. PBOT & PMID Evaluation for Cycle 12 0 2 C. 2011 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1632

References:

1. WCAP-16763-P, "Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Comanche Peak Unit 2 Nuclear Plant Using the ASTRUM Methodology," March 2009.

2. LTR-LIS-09-562, "Transmittal of Updated Comanche Peak PCT Summary Sheets," September 2009.

Notes:

None to TXX-1 2053 Page 4 of 4 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/22/2012 Analysis Information EM: NOTRUMP Analysis Date: 6/8/2007 Limiting Break Size: 4 inch FQ: 2.5 FdH: 1.6 Fuel: OFA SGTP(%): 10 Notes:

Clad Temp(°F) Ref. Notes LICENSIS BASIS Analysis-Of-Record PCT 1210 1 PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2011 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1210

References:

1. WCAP-16840-P, "Comanche Peak Nuclear Power Plant Stretch Power Uprate Licensing Report," August 2007. (Results are included in TXX-07107, "Comanche Peak Steam Electric Station (CPSES), Docket Nos. 50-445 and 50-446, Submittal of the CPSES Units I and 2 Large and Small Break LOCA Analyses," July 31, 2007.)

Notes:

None