CP-201800310, Annual Report of Changes in Peak Cladding Temperature

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Annual Report of Changes in Peak Cladding Temperature
ML18172A130
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 06/19/2018
From: Hope T
Vistra Operations Company
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201800310, TXX-18034
Download: ML18172A130 (17)
v • d • e


Text

ENERGY

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Luminant Timothy A. Hope Manager, Regulatory Affairs Luminant P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043 o 254.897.6370 CP-201800310 TXX-18034 U.S. Nuclear Regulatory Commission Ref 10 CFR 50.46(a)(3)(ii)

ATIN: Document Control Desk Washington, DC 20555-0001 6/19/2018

SUBJECT:

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

REFERENCES:

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), Vistra Operations Company LLC (Vistra OpCo) 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 (LBLOCA) and Small-Break Loss-of-Coolant Accident (SBLOCA) analyses for Units 1 and 2 were performed for CPNPP with the approved Westinghouse methodologies listed in Technical Specification 5.6.5. Per Reference 1, Vistra Op Co previously submitted information regarding fuel pellet thermal conductivity with fuel burn up in the Westinghouse Best Estimate LBLOCA analysis methodology for CPNPP Units 1 and 2. Also, per Reference 2, Vistra OpCo 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).

Vistra OpCo 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 2017. 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 2017. fllO C----

1Jf rf._

6555 SIERRA DRIVE IRVING, TEXAS 75039 0214-812-4600 VISTRAENERGY.COM

TXX-18034 Page 2 of 2 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 2017. provides the calculated LBLOCA and SBLOCA PCT margin allocations in effect for the 2017 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 Ken Vehstedt at (254} 897-6296.

Sincerely, Attachments 1. Assessments of Specific Changes and Enhancements to the Westinghouse Evaluation Models

2. CPNPP Units 1 and 2 Peak Cladding Temperatures c- Kriss Kennedy, Region IV Margaret M. O'Banion, NRR Resident Inspectors, Comanche Peak to TXX-18034 Assessments of Specific Changes and Enhancements Page 1 of 7 to the Westinghouse Evaluation Models 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 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM 1981 Westinghouse Large Break LOCA Evaluation Model with BASH 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-18034 Assessments of Specific Changes and Enhancements Page 2 of 7 to the Westinghouse Evaluation Models COMANCHE PEAK UNIT 2 CYCLE 17 PBOT/PMID VIOLATIONS

Background

The Comanche Peak Unit 2 Cycle 17 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 17 operation.

This item represents a change in plant configuration or associated set points, distinguished from an evaluation model change in Section 4 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 violations for Comanche Peak Unit 2 Cycle 17 was determined via a plant-specific evaluation to be 0°F.

to TXX-18034 Assessments of Specific Changes and Enhancements Page 3 of 7 to the Westinghouse Evaluation Models ERROR IN THE UPPER PLENUM FLUID VOLUME CALCULATION

Background

An error was found in the fluid volume calculation in the upper plenum where the support column outer diameter was being used instead of the inner diameter. The correction of this error lead to a reduction in the upper plenum fluid volume used in the Appendix K Large Break LOCA and Small Break LOCA analyses. The corrected values represent a less than 1 % change in the total RCS fluid volume and will be incorporated on a forward-fit basis, based on the evaluated impact on the current licensing basis analysis results.

These changes represent a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 1981 Westinghouse Large Break LOCA Evaluation Model with BASH.

1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect The differences in the upper plenum fluid volume are relatively minor and have been evaluated to have a negligible effect on large and small break LOCA analysis results, leading to an estimated PCT impact of 0°F.

to TXX-18034 Assessments of Specific Changes and Enhancements Page 4 of 7 to the Westinghouse Evaluation Models COMANCHE PEAK UNIT 1 CYCLE 20 PBOT/PMID VIOLATION

Background

The Comanche Peak Unit 1 Cycle 20 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 20 operation.

This item represents a change in plant configuration or associated set point, distinguished from an evaluation model change in Section 4 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 20 was determined via a plant-specific evaluation to be 0°F.

to TXX-18034 Assessments of Specific Changes and Enhancements Page 5 of 7 to the Westinghouse Evaluation Models INCONSISTENT APPLICATION OF NUMERICAL RAMP APPLIED TO THE ENTRAINED LIQUID/VAPOR INTERFACIAL DRAG COEFFICIENT

Background

A numerical ramp which was used to account for the disappearance of the entrained liquid phase was applied to the entrained liquid / vapor interfacial drag coefficient. The numerical ramp was applied such that the interfacial drag coefficient used in the solution of the entrained liquid and vapor momentum equations was not consistent. WCOBRA/TRAC was updated to apply the numerical ramp prior to usage of the interfacial drag coefficient in the momentum equations, such that a consistent interfacial drag coefficient was used in the entrained liquid and vapor momentum equations.

This item represents a Non-Discretionary Change in accordance with 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 Based on the code validation results, the impact of correcting the error is estimated to have a 0°F impact on PCT.

to TXX-18034 Assessments of Specific Changes and Enhancements Page 6 of 7 to the Westinghouse Evaluation Models INAPPROPRIATE RESETTING OF TRANSVERSE LIQUID MASS FLOW

Background

In the WCOBRA/TRAC routine which evaluates the mass and energy residual error of the time step solution, the transverse liquid mass flow is reset as the liquid phase disappears. The routine is updated to remove the resetting of the transverse liquid mass flow since the routine is to only evaluate the residual error based on the time step solution values.

This item represents a Non-Discretionary Change in accordance with 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 Based on the code validation results and limited applicability of the logic removed, correcting the error is estimated to have a 0°F impact on PCT.

to TXX-18034 Assessments of Specific Changes and Enhancements Page 7 of 7 to the Westinghouse Evaluation Models STEADY-STATE FUEL TEMPERATURE CALIBRATION METHOD

Background

In the Automated Statistical Treatment of Uncertainty Method (ASTRUM) Best-Estimate (BE) Large-Break Loss-of-Coolant Accident (LBLOCA) Evaluation Model (EM), the steady-state fuel pellet temperature calibration method involves solving for the hot gap width (AGFACT) to calibrate the fuel temperature for each fuel rod. In some infrequent situations, small non-conservatisms can occur in the calibration process such that the resulting fuel pellet temperature will be slightly lower than intended and outside the acceptable range defined by Table 12-6 of WCAP-16009-P /NP-A [1].

This issue has been evaluated to estimate the impact on ASTRUM BE LBLOCA analysis results. The resolution of this issue represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.

Affected Evaluation Model(s) 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A review of licensing basis analyses concluded that the potential non-conservatisms in the fuel pellet temperature calibration did not occur for the limiting analysis cases. Therefore, an estimated PCT impact of 0°F is assigned for 10 CFR 50.46 reporting purposes.

Reference(s)

1) WCAP-16009-P /NP-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM)," January 2005.

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 1 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING 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 Burndown

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. 2017 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 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown," September 20, 2012.
3. LTR-LIS-13-359, "Comanche Peak Units 1 and 210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
4. LTR-LIS-14-43, "Comanche Peak Units 1 and 210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 2 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Cycle 20 Revision Date: 2/1/2018 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 LICENSING 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 Burndown

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. 2017 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-17-322, "10 CFR 50.46 Reporting Text and LBLOCA PCT Rackup Update for the Evaluation of the Comanche Peak Unit 1 Cycle 20 PBOT/PMID Violations," September 2017.
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 Burndown," September 20, 2012.
4. LTR-LIS-13-359, "Comanche Peak Units 1 and 210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
5. LTR-LIS-14-43, "Comanche Peak Units 1 and 210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 3 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Cycle 19 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING 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 Burndown

2. Revised Heat Transfer Multiplier Distributions -6 4
3. Error in Burst Strain Application 21 5 B. PLANNED PLANT MODIFICATION EVALUATIONS
1. PBOT /PMlD Violation 0 2 C. 2017 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-16-170, "LBLOCA 10 CFR 50.46 Reporting Text and PCT Rackup Sheet Update for the Evaluation of the Comanche Peak Unit 1 Cycle 19 PBOT/PMID Violations," April 2016.
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 Burndown," September 20, 2012.
4. LTR-LIS-13-359, "Comanche Peak Units 1 and 210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
5. LTR-LIS-14-43, "Comanche Peak Units 1 and 210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 4 of 8 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING 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. 2017 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 1 and 2 Large and Small Break LOCA Analyses," July 31, 2007.)

Notes:

None to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 5 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING 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 Burndown

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. 2017 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-12-410, "Comanche Peak Units 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown," September 20, 2012.
3. LTR-LIS-13-359, "Comanche Peak Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
4. LTR-LIS-13-472, "Comanche Peak Units 1 and 210 CFR 50.46 Reports for Changes to Grid Blockage Ratio and Porosity," October 2013.
5. LTR-LIS-14-43, "Comanche Peak Units 1 and 210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 6 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Cycle 16 Revision Date: 2/1/2018 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 LICENSING 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 & PMlD Evaluation 0 2 C. 2017 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 210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
5. LTR-LIS-13-472, "Comanche Peak Units 1 and 210 CFR 50.46 Reports for Changes to Grid Blockage Ratio and Porosity," September 2013.
6. LTR-LIS-14-43, "Comanche Peak Units 1and210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 7 of 8 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Cycle17 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING BASIS Analysis-Of-Record PCT 632 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 Violation 0 2 C. 2017 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-17-124, "10 CFR 50.46 Reporting Text and LBLOCA PCT Rackup Update for the Evaluation of the Comanche Peak Unit 2 Cycle 17 PBOT /PMlD Violations," March 2017.
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 Burndown," September 20, 2012.
4. LTR-LIS-13-359, "Comanche Peak Units 1 and 210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
5. LTR-LIS-13-472, "Comanche Peak Units 1and210 CFR 50.46 Reports for Changes to Grid Blockage Ratio and Porosity," September 2013.
6. LTR-LIS-14-43, "Comanche Peak Units 1 and 210 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.

Notes:

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

to TXX-18034 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 8 of 8 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/1/2018 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 LICENSING 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. 2017 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 1 and 2 Large and Small Break LOCA Analyses," July 31, 2007.)

Notes:

None

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