CP-201700193, Annual Report of Changes in Peak Cladding Temperature

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Annual Report of Changes in Peak Cladding Temperature
ML17111A866
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 04/12/2017
From: Hope T
TEX Operations Company, Vistra Operations Company
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201700193, TXX-17031
Download: ML17111A866 (13)
v • d • e


Text

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Luminant Timothy A. Hope Manager, Regulatory Affairs Luminant P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043 0 254.897.6370 m 817.360.6882 CP-201700193 TXX-17031 U.S. Nuclear Regulatory Commission Ref 10 CFR 50.46{a)(3)(ii)

ATIN: Document Control Desk Washington, DC 20555-0001 4/12/2017

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:

1 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, Luminant Power previously submitted information regarding fuel pellet thermal conductivity with fuel burnup in theWestinghouse Best Estimate LBLOCA analysis methodology for CPNPP Units 1 and 2. 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}.

1 TEX Operations Company LLC and Comanche Peak Power Company LLC are the current NRC licensees. On December 14, 2016, License Amendment Request 16-003 (ML16351A200) submitted an administrative change to change the licensee name "TEX Operations Company LLC" to "Vistra Operations Company LLC".

1601 BRYAN STREET DALLAS, TEXAS 75201 0 214-812-4600 VISTRAENERGY.COM

TXX-17031 Page 2 of 2 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 2016. 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 2016.

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 2016. provides the calculated LBLOCA and SBLOCA PCT margin allocations in effect for the 2016 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,

  • ~~

Timothy A. Hope 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. Watford, NRR Resident Inspectors, Comanche Peak to TXX-17031 Assessments of Specific Changes and Enhancements Page 1 of 4 _ 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 Estimated Effect The nature of these changes leads to an estimated Peak Cladding Temperature (PCT) impact of 0°F.

to TXX-17031 Assessments of Specific Changes and Enhancements Page 2 of 4 to the Westinghouse Evaluation Models ERROR IN OXIDATION CALCULATIONS

Background

A closely-related group of errors were discovered in the WCOBRA/TRAC software program. The errors are related to the calculation of high temperature oxidation within a realistic large break loss-of-coolant accident (LOCA) calculation. This issue has been evaluated to estimate the impact on the Automated Statistical Treatment of Uncertainty Method (ASTRUM) and the Best-Estimate (BE) Large-Break Loss of- Coolant Accident (LBLOCA) licensing-basis 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) 1996 Westinghouse Best-Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect It was determined that correcting the high temperature oxidation calculation in WCOBRA/TRAC is estimated to have a negligible impact on the BE LBLOCA peak cladding temperature (PCT) analysis results, leading to an estimated PCT impact of 0°F for 10 CFR 50.46 reporting purposes.

to TXX-17031 Assessments of Specific Changes and Enhancements Page 3 of 4 to the Westinghouse Evaluation Models ERROR IN USE OF ASME STEAM TABLES

Background

The American Society of Mechanical Engineers (ASME) steam tables are used to calculate the steady-state upper head liquid temperature as a function of the pressure and specific enthalpy in the ASTRUM software program.

The steam table applicable to steam/gas is used to determine the upper head fluid temperature. However, the water in the upper head is in the subcooled liquid state during normal operation (and the steady-state calculation). Therefore, the steam table applicable to liquid should be used to determine the upper head fluid temperature. This issue has been evaluated to estimate the impact on Automated Statistical Treatment of Uncertainty Method (ASTRUM) Best-Estimate (BE) Large-Break Loss-of-Coolant Accident (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 It was determined that the temperatures calculated by the ASME steam tables applicable to the steam/gas side and the liquid side are very similar within the typical upper head pressure and liquid specific enthalpy ranges.

Therefore, this error was evaluated to have a negligible impact on the ASTRUM BE LBLOCA analysis results, leading to an estimated PCT impact of 0°F for 10 CFR 50.46 reporting purposes.

to TXX-17031 Assessments of Specific Changes and Enhancements Page 4 of 4 to the Westinghouse Evaluation Models COMANCHE PEAK UNIT 1CYCLE19 PBOT/PMID VIOLATION

Background

The Comanche Peak Unit 1Cycle19 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 19 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 1Cycle19 was determined via a plant-specific evaluation to be O°F.

to TXX-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 1 of 7 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 2/8/2017 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. 2016 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 1and210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," July 2013.
4. 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 burndown, see Reference 2.

to TXX-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 2 of 7 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 1 RETIRED-Cycle 18 Utility Name: Luminant Revision Date: 2/8/2017 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 Degradation and Peaking 122 3 (a)

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. 2016 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-14-414, "LBLOCA PCT Rackup Sheet Update for the Evaluation of the Comanche Peak Unit 1 Cycle 18 PBOT/PMID Violations," September 2014.
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 1and210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions,"

July 2013.

5. 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 burndown, see Reference 3.

to TXX-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 3 of 7 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: 2/8/2017 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 Degradation and Peaking 122 3 (a)

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. 2016 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 1Cycle19 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 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions,"

July 2013. I

5. 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 burndown, see Reference 3.

to TXX-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 4 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 1 Utility Name: Luminant Revision Date: 2/8/2017 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. 2016 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-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 5 of 7 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/8/2017 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 Degradation 190 2 (a)

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. 2016 ECCS MODEL ASSESSMENTS
1. None 0 D.OTHER 1.None 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 1and210 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions,"

July 2013.

4. LTR-LIS-13-472, "Comanche Peak Units 1and210 CFR 50.46 Reports for Changes to Grid Blockage Ratio and Porosity,"

October 2013.

5. LTR-LIS-14-43, "Comanche Peak Units 1 and 2 10 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-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 6 of 7 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Comanche Peak Unit 2 Cycle 16 Utility Name: Luminant Revision Date: 2/8/2017 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 Degradation 190 3 (a)

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. 2016 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 Burndown," September 20, 2012.
4. LTR-LIS-13-359, "Comanche Peak Units 1and210 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 1and210 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-17031 CPNPP Units 1 and 2 Peak Cladding Temperatures Page 7 of 7 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Comanche Peak Unit 2 Utility Name: Luminant Revision Date: 2/8/2017 Analysis Information EM: NOTRUMP Analysis Date: 6/8/2007 Limiting Break Size: 4inch 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. 2016 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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