CP-201100297, Annual Report of Changes in Peak Cladding Temperature

Annual Report of Changes in Peak Cladding Temperature

ML110740025
Person / Time
Site:	Comanche Peak
Issue date:	03/03/2011
From:	Madden F, Flores R Luminant Generation Co, Luminant Power
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CP-201100297, TXX-11035
Download: ML110740025 (10)

Text

Rafael Flores Luminant Power Senior Vice President P 0 Box 1002

& Chief Nuclear Officer 6322 North FM 56 rafael.flores@Luminant.com Glen Rose, TX 76043 Lum inant T 254 897 5550 C 817 559 0403 F 254 897 6652 CP-201100297 Ref. # 10CFR50.46 Log # TXX-11035 March 3, 2011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

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 1 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 2010. The review concludes that the effect of changes to, or errors in, the Evaluation Models on the limiting transient PCT is not significant for 2010.

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

Attachment 1 provides an assessment of the specific changes and enhancements to the Westinghouse Evaluation Models for 2010. 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 2010 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, Comanche Peak 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 Callaway Comanche Peak

• Diablo Canyon - Palo Verde

• San Onofre South Texas Project

• Wolf Creek

U. S. Nuclear Regulatory Commission TXX-1 1035 Page 2 March 3, 2011 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: AjW ý B:Fred W. Madden Director, Oversight & Regulatory Affairs Attachments - 1. Assessment of specific changes and enhancements to the Westinghouse Evaluation Models for 2010

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-11035 Page 1 of4 URANIA-GADOLINIA PELLET THERMAL CONDUCTIVITY CALCULATION

Background

Two errors were discovered in the pellet thermal conductivity calculation for urania-gadolinia pellets in the SBLOCTA code. First, the calculation did not include the terms required to adjust for pellet densities other than 95% of the theoretical density. Second, the conversion from Fahrenheit to Rankine used an adder of 459 instead of 459.67. These errors have been corrected and evaluated for impact on existing Small Break LOCA analysis results. 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 SBLOCTA sensitivity calculations led to an estimated PCT effect of 0°F for existing Small Break LOCA analysis results.

of TXX-1 1035 Page 2 of 4 PELLET CRACK AND DISH VOLUME CALCULATION

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 1981 Westinghouse Large Break LOCA Evaluation Model with BASH 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.

of TXX-11035 Page 3 of 4 TREATMENT OF VESSEL AVERAGE TEMPERATURE UNCERTAINTY

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 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 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 07F.

of TXX-11035 Page 4 of 4 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 forwardfit 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.

to TXX-11035 Page 1 of 4 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 1/14/11 Analysis Information EM: ASTRUM (2004) Analysis Date: 7/27/07 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

1. PBOT & PMID Evaluation for Cycle 15 32 2 C. 2010 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1524

References:

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

2. LTR-LIS-08-649, "Transmittal of Updated Comanche Peak Unit 1 (TBX) PCT Summary Sheets," March 2010.

Notes:

None to TXX-11035 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: 1/14/11 Analysis Information EM: NOTRUMP Analysis Date: 6/8/07 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 1013 I PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2010 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

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

References:

1. WCAP- I6840-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-11035 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: 1/14/11 Analysis Information EM: ASTRUM (2004) Analysis Date: 7/27/07 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 I 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. 2010 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

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

References:

1. WCAP-16762-P, "Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Comanche Peak Unit 2 Nuclear Plant Using the ASTRUM Methodology," July 2007.

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

Notes:

None to TXX-11035 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: 1/14/11 Analysis Information EM: NOTRUMP Analysis Date: 6/8/07 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 I PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2010 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