Text

Annual Report of Changes in Peak Cladding Temperature
	ML16097A415
Person / Time
Site:	Comanche Peak
Issue date:	03/31/2016
From:	Hope T, Peters K; Luminant Generation Co, Luminant Power
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	CP-201600195, TXX-16037
	Download: ML16097A415 (13)
	v • d • e

Kenneth J. Peters Luminant Power II Senior Vice President

& Chief Nuclear Officer Kenneth.Peters@Luminant.com P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 Luminant T 254 897 6565 c 817 776 0037 F 254 897 6652 CP-201600195 Ref. # 10CFR50.46 TXX-16037 March 31, 2016 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 REF: 1. Letter logged TXX-12146, dated October 18, 2012, from Rafael Flores of Luminant Power to the NRC regarding "30-Day Report for Significant Change in Peak Clad Temperature"

2. Letter logged TXX-14058, dated April 22, 2014, from Rafael Flores of Luminant Power to the NRC. regarding "30-Day Report for Significant Change in Peak Clad 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 1and2. The Large-Break Loss-of-Coolant-Accident (LBLOCA) and Small-Break Loss-of-Coolant Accident (SBLOCA) analyses for Units 1 and 2 were performed for Luminant Power with the approved Westinghouse methodologies listed in Technical Specification 5.6.5. Per Reference 1, Luminant Power previously submitted information regarding fuel pellet thermal conductivity with fuel burnup in the Westinghouse Best Estimate LBLOCA analysis methodology for CPNPP Units 1and2. Also, per Reference 2, Luminant Power submitted information regarding an evaluation of revised Heat Transfer Multiplier Distributions, changes to Grid Blockage Ratio and Porosity, and application of a corrected Burst Strain in the Westinghouse Best Estimate LBLOCA analysis methodology for CPNPP Unit 2 and its effect on Peak Cladding Temperature (PCT).

Luminant Power has reviewed the notification of 10CFR50.46 reporting information pertaining to the Emergency Core Cooling System (ECCS) Evaluation Model changes that were implemented by Westinghouse for 2015. The review concludes that the effect of additional changes to, or errors in, the Evaluation Models on the limiting transient PCT were not significant for 2015.

This report of the ECCS Evaluation Model changes provides an update on an annual basis. Attachment 1 provides an assessment of the specific changes and enhancements to the Westinghouse Evaluation Models for 2015.

U.S. Nuclear Regulatory Commission TXX-16037 Page 2 of 2 03/3112016 provides the calculated LBLOCA and SBLOCA PCT margin allocations in effect for the 2015 Comanche Peak Units 1 and 2 Evaluation Models. There were no changes, error corrections, or enhancements to the 1985 Westinghouse Small Break Loss-of-Coolant Accident Evaluation Model with NOTRUMP. The PCT values determined in the LBLOCA 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 other action is required.

This communication contains no new commitments regarding CPNPP Units 1 and 2.

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

Sincerely, Luminant Generation Company LLC Kenneth J. Peters By~~ Timothy A. Hope Manager, Regulatory Affairs Attachments - 1. Assessment of Specific Changes and Enhancements to the Westinghouse Evaluation Models for 2015

2. CPNPP Units 1 and 2 Peak Cladding Temperatures c- Marc L. Dapas, Region IV Margaret M. Watford, NRR Resident Inspectors, Comanche Peak to TXX-16037 Page 1of4 Assessment of Specific Changes and Enhancements to the Westinghouse Evaluation Models for 2015 LOWER SUPPORT PLATE, CORE BARREL, AND VESSEL WALL UNHEATED CONDUCTOR ERRORS

Background

Modeling errors were discovered in the lower support plate, core barrel, and vessel cladding unheated conductors in the Best-Estimate Large Break Loss-of-Coolant Accident (BE LBLOCA) analysis-of-record.

The modeling errors impacted the volume and surface area of the core barrel, the surface area and thermal resistance of the lower support plate, and the thermal resistance of the vessel wall.

The resolution of these issues represents a closely-related group of Non-Discretionary Changes in the application of the Evaluation Model as described in Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A qualitative evaluation was completed concluding that the modeled net stored energy and heat transfer rate of the vessel wall, core barrel, and lower support plate unheated conductors were adequate. This error is estimated to have a Peak Cladding Temperature (PCT) impact of 0°F.

to TXX-16037 Page 2 of 4 Assessment of Specific Changes and Enhancements to the Westinghouse Evaluation Models for 2015 CORE CHANNEL GAP ERROR

Background

A modeling error was discovered in the Best-Estimate Large Break Loss-of-Coolant Accident (BE LBLOCA) analysis-of-record. The modeling error over-represented the flow area between the guide tube and non-guide tube core average channels.

The resolution of this issue represents a Non-Discretionary Change in the application of the Evaluation Model as described in Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A qualitative evaluation was completed concluding the magnitude of the error is negligible. The error is estimated to have a Peak Cladding Temperature (PCT) impact of 0°F.

to TXX-16037 Page 3 of 4 Assessment of Specific Changes and Enhancements to the Westinghouse Evaluation Models for 2015 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) 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect The nature of these changes leads to an estimated Peak Cladding Temperature (PCT) impact of 0°F.

to TXX-16037 Page 4 of4 Assessment of Specific Changes and Enhancements to the Westinghouse Evaluation Models for 2015 COMANCHE PEAK UNIT 2 EVALUATION OF LEAKING SPLIT FLOW BYPASS VALVES

Background

Comanche Peak Unit 2 identified that the split flow bypass valve (SFBV) was leaking which results in some portion of the auxiliary feedwater (AFW) flow being delivered to the steam generator via the main feedwater (lower) nozzle instead of the AFW (upper) nozzle. This scenario was evaluated against the Comanche Peak small-break loss-of-coolant accident (SBLOCA) analysis of record. The scenario is characterized as a change in a plant configuration, distinguished from an evaluation model change in Section 4 of WCAP-13451.

Affected Evaluation Model(s) 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect A qualitative evaluation was performed and concluded that this scenario will not challenge the heat removal capability of the steam generators during a SBLOCA transient. As such, this change has a negligible impact on the SBLOCA transient results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

to TXX-16037 Page 1of7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 2/1/2016 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 1 PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Evaluation of Fuel Pellet Thermal Conductivity 122 2 (a)

Degradation and Peaking Factor Bumdown

2. Revised Heat Transfer Multiplier Distributions -6 3

3. Error in Burst Strain Application 21 4 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2015 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 1629

References:

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

2. LTR-LIS-12-410, "Comanche Peak Units 1and2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdown," September 20, 2012.

3. LTR-LIS-13-359, "Comanche Peak Units 1 and 2 10CFRS0.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.

4. LTR-LIS-14-43, "Comanche Peak Units 1 and 2 10CFR50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

(a) This evaluation credits peaking factor bumdown, see Reference 2.

to TXX-16037 Page 2 of 7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name:

Revision Date:

Luminant 2/1/2016 Cycle 18 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 1 PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. Evaluation of Fuel Pellet Thermal Conductivity 122 3 (a)

Degradation and Peaking Factor Bumdown

2. Revised Heat Transfer Multiplier Distributions -6 4

3. Error in Burst Strain Application 21 5 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. PBOT/PMID Violation 0 2 C. 2015 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT= 1629

References:

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

2. LTR-LIS-14-414, "LBLOCA PCT Rackup Shet:L Update for the Evaluation of the ComRnche Peak Unit I Cycle 18 PBOT/PMID Violations," September 2014.

3. LTR-LIS-12-410, "Comanche Peak Units I and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdown," September 20, 2012.

4. LTR-LIS-13-359, "Comanche Peak Units I and 2 I OCFR50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.

5. LTR-LIS-14-43, "Comanche Peak Units I and 2 IOCFR50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

(a) This evaluation credits peaking factor bumdown, see Reference 3.

to TXX-16037 Page 3 of 7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 211/2016 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 1013 1 PCT Assessments (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS

1. None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2015 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 1and2 Large and Small Break LOCA Analyses," July 31, 2007.)

Notes:

None to TXX-16037 Page4 of7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/1/2016 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. Evaluation of Fuel Pellet Thermal Conductivity 190 2 (a)

Degradation and Peaking Factor Bumdown

2. Revised Heat Transfer Multiplier Distributions -17 3

3. Changes to Grid Blockage Ratio and Porosity 24 4

4. Error in Burst Strain Application 21 5 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. None 0 C. 2015 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 1850

References:

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

2. LTR-LIS-12-410, "Comanche Peak Units 1and2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdown," September 20, 2012.

3. LTR-LIS-13-359,"Comanche Peak Units 1 and 2 10CFR50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.

4. LTR-LIS-13-472, "Comanche Peak Units 1and2 10CFR50.46 Reports for Changes to Grid Blockage Ratio and Porosity," October 2013.

5. LTR-LIS-14-43, "Comanche Peak Units 1 and 2 10CFR50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

(a) This evaluation credits peaking factor bumdown, see Reference 2.

to TXX-16037 Page 5 of 7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name:

Revision Date:

Luminant 2/1/2016 Cycle 16 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. Evaluation of Fuel Pellet Thermal Conductivity 190 3 (a)

Degradation and Peaking Factor Bumdown

2. Revised Heat Transfer Multiplier Distributions -17 4

3. Changes to Grid Blockage Ratio and Porosity 24 5

4. Error in Burst Strain Application 21 6 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. PBOT/PMID Evaluation 0 2 C. 2015 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 1850

References:

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

2. LTR-LIS-15-317, "LBLOCA PCT Rackup Sheet Update for the Evaluation of the Comanche Peak Unit 2 Cycle 16 PBOT/PMID Violations" September 2015.

3. LTR-LIS-12-410, "Comanche Peak Units 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdown," September 20, 2012.

4. LTR-LIS-13-359, "Comanche Peak Units 1 and 2 10CFRS0.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.

5. LTR-LIS-13-472, "Comanche Peak Units 1and2 10CFR50.46 Reports for Changes to Grid Blockage Ratio and Porosity," October 2013.

6. LTR-LIS-14-43, "Comanche Peak Units 1 and 2 10CFRS0.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

(a) This evaluation credits peaking factor bumdown, see Reference 3.

to TXX-16037 Page 6 of 7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Cycle 15 Revision Date: 2/112016 Retired 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. Evaluation of Fuel Pellet Thermal Conductivity 190 3 (a)

Degradation and Peaking Factor Burndown

2. Revised Heat Transfer Multiplier Distributions -17 4

3. Changes to Grid Blockage Ratio and Porosity 24 5

4. Error in Burst Strain Application 21 6 B. PLANNED PLANT MODIFICATION EVALUATIONS

1. PBOT/PMID Evaluation 0 2 C. 2015 ECCS MODEL ASSESSMENTS

1. None 0 D. OTHER

1. None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 1850

References:

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

2. LTR-LIS-14-173, "LBLOCA PCT Rackup Sheet Update for the Evaluation of the Comanche Peak Unit 2 Cycle 15 PBOT/PMID Violations" March 2014.

3. LTR-LIS-12-410, "Comanche Peak Units 1and2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Bumdown," September 20, 2012.

4. LTR-LIS-13-359, "Comanche Peak Units 1and2 10CFR50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.

5. LTR-LIS-13-472, "Comanche Peak Units 1and2 10CFR50.46 Reports for Changes to Grid Blockage Ratio and Porosity," October 2013.

6. LTR-LIS-14-43, "Comanche Peak Units 1 and 2 10CFR50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

(b) This evaluation credits peaking factor bumdown, see Reference 3.

to TXX-16037 Page 7 of 7 CPNPP Units 1 and 2 Peak Cladding Temperatures Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/1/2016 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. 2015 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 1and2 Large and Small BreakLOCA Analyses," July 31, 2007.)

Notes:

None