L-PI-22-032, CFR 50.46 LOCA Annual Report

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CFR 50.46 LOCA Annual Report
ML22167A178
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 06/16/2022
From: Hanson H
Northern States Power Company, Minnesota, Xcel Energy
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-22-032
Download: ML22167A178 (13)
v • d • e


Text

1717 Wakonade Drive Welch, MN 55089 L-PI-22-032 10 CFR 50.46 June 16, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Units 1 and 2 Docket Nos. 50-282 and 50-306 Renewed Facility Operating License Nos. DPR-42 and DPR-60 2021 10 CFR 50.46 LOCA Annual Report

References:

1) Westinghouse Letter NSPM-LOCA-TM-A5-000001 Prairie Island Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2021, dated February 7, 2022 Pursuant to 10 CFR 50.46(a)(3)(ii), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter NSPM), hereby submits the 2021 annual report of changes and errors associated with the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2 Emergency Core Cooling System (ECCS) analyses (Enclosure 1).

PINGP has reviewed the above Reference, which addresses 10 CFR 50.46 reporting information pertaining to the Emergency Core Cooling System (ECCS) Evaluation Model changes that were implemented by Westinghouse for 2021. The review concludes that the effect of changes to, or errors in, the Evaluation Models on the limiting transient peak cladding temperature (PCT) is not significant for 2021 and remains unchanged from the 2020 annual report. pages 3 through 4 provides an assessment of the specific changes and enhancements to the Westinghouse Evaluation Models for 2021. These model changes and enhancements do not have impacts on the PCT and, generally, will not be presented on the PCT rack-up forms. pages 5 through 10 provides PCT rack-up forms for the calculated Large Break Loss-of-Coolant Accident (LOCA) and Small Break LOCA PCT margin allocations in effect for the 2021 PINGP Evaluation Models. The PCT values determined in the Large Break and Small Break LOCA analysis of record, combined with all of the PCT allocations, remain below the 10 CFR 50.46(b)(1) regulatory limit of 2200°F. Therefore, PINGP is in compliance with 10 CFR 50.46 requirements and no reanalysis or other action is required.

fl Xcel Energy

L-Pl-22-032 Page 2 If you have any questions about this submittal, please contact Carrie Seipp, Senior Regulatory Engineer, at 612-330-5576.

Summary of Commitments This letter makes no new commitments and no revisions to existing commitments.

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I Plant Manager, Prairie Island Nuclear Ile! ting Plant Northern States Power Company - Minnesota Enclosure (1) cc:

Administrator, Region 111, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

ENCLOSURE 1 Westinghouse Letter NSPM-LOCA-TM-A5-000001 Prairie Island Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2021 Page 1 of 11

Westinghouse Non-Proprietary Class 3 Westinghouse Electric Company 1000 Westinghouse Drive Cranberry Township, Pennsylvania 16066 USA Direct tel: (412) 374-5598 e-mail: mcmillh@westinghouse.com Our ref: NSPM-LOCA-TM-A5-000001 Prairie Island Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2021

Dear Sir or Madam:

This is a notification of 10 CFR 50.46 reporting information pertaining to the Westinghouse Electric Company Evaluation Models/analyses. As committed to in WCAP-13451, Westinghouse Methodology for Implementation of 10 CFR 50.46 Reporting, Westinghouse is providing an Annual Report for Emergency Core Cooling System (ECCS) Evaluation Model changes and errors for the 2021 model year. All necessary standardized reporting pages for any changes and errors for the Evaluation Models utilized for your plant(s) are enclosed, consistent with the commitment following the NUPIC audit in early 1999. Peak Clad Temperature (PCT) summary sheets are enclosed. All necessary revisions for any non-zero, non-discretionary PCT changes have been included. Changes with estimated PCT impacts of 0°F may not be presented on the PCT summary sheet. The Evaluation Model changes and errors (except any plant-specific errors in the application of the model) have been provided to the NRC via Westinghouse letter.

This information is for your use in making a determination relative to the reporting requirements of 10 CFR 50.46. The information that is provided in this letter was prepared in accordance with Westinghouse's Quality Management System (QMS). Please contact your LOCA plant cognizant engineer (PCE), Julie L. Hartz (412-374-2321), if there are any questions concerning this information.

Author:

(Electronically Approved)*

Heather McMillen Verified:

(Electronically Approved)*

Approved:

(Electronically Approved)*

Julie L. Hartz Amy J. Colussy

Attachment:

10 CFR 50.46 Reporting Text and PCT Summary Sheets (9 Pages)

  • Electronically approved records are authenticated in the electronic document management system.

© 2022 Westinghouse Electric Company LLC All Rights Reserved Page 2 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 1 of 9 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 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 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect The nature of these changes leads to an estimated peak cladding temperature impact of 0°F.

Page 3 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 2 of 9 REDUCTION IN FLOW AREA TO THE BOTTOM OF THE BARREL/BAFFLE REGION

Background

For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt. The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated.

This item 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 The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.

Page 4 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 3 of 9 LOCA Peak Cladding Temperature (PCT) Summary Plant Name:

PRAIRIE ISLAND 1 EM:

NOTRUMP AOR

Description:

Appendix K Small Break Summary Sheet Status: Current PRAIRIE ISLAND 1 NSP_LOCA-50.46_NSP_Base_Appendix_K_SBLOCA - 1.2 V.V PCT (°F)

Reference #

Note #

ANALYSIS-OF-RECORD 959 1

AOR + ASSESSMENTS PCT =

959.0 °F REFERENCES 1 LTR-LIS-08-158, Transmittal of Future Prairie Island Units 1 and 2 PCT Summaries, February 2008.

NOTES:

(a) None Version: PRAIRIE ISLAND 1 NSP_LOCA-50.46_NSP_Base_Appendix_K_SBLOCA - 1.2 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved Page 5 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 4 of 9 LOCA Peak Cladding Temperature (PCT) Summary Plant Name:

PRAIRIE ISLAND 1 EM:

ASTRUM (2004)

AOR

Description:

Best Estimate Large Break Summary Sheet Status: IFBA/Gad PRAIRIE ISLAND 1 NSP_LOCA-50.46_NSP_IFBA_GAD_ASTRUM - 1.3 V.V PCT (°F)

Reference #

Note #

ANALYSIS-OF-RECORD 1765 1

ASSESSMENTS*

Delta PCT

(°F)

Reference #

Note #

Reporting Year**

1.

Revised Heat Transfer Multiplier Distributions

-2 3

2013 2.

Error in Burst Strain Application 25 4

2013 3.

Evaluation of the Introduction of IFBA Fuel 0

2 2018 4.

Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown 227 5

(a) 2012 AOR + ASSESSMENTS PCT =

2015.0 °F The licensee should determine the reportability of these assessments pursuant to 10 CFR 50.46.

    • The Reporting Year refers to the annual reporting year in which this assessment was included.

REFERENCES 1

WCAP-17783-P, Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Prairie Island Units 1 and 2 with Replacement Steam Generators Using ASTRUM Methodology, June 2013.

2 LTR-LIS-15-287, Rev. 1, Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting for the Revised Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown Evaluation and the Introduction of IFBA Fuel, September 2015.

3 LTR-LIS-13-366, Revision 1, Prairie Island Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions, August 2013.

4 LTR-LIS-14-50, Prairie Island Units 1 and 2 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction, January 2014.

5 LTR-LIS-12-414, Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown, September 2012.

Version: PRAIRIE ISLAND 1 NSP_LOCA-50.46_NSP_IFBA_GAD_ASTRUM - 1.3 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved Page 6 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 5 of 9 NOTES:

(a) This evaluation credits peaking factor burndown, see Reference 5.

Version: PRAIRIE ISLAND 1 NSP_LOCA-50.46_NSP_IFBA_GAD_ASTRUM - 1.3 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved Page 7 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 6 of 9 LOCA Peak Cladding Temperature (PCT) Summary Plant Name:

PRAIRIE ISLAND 2 EM:

NOTRUMP AOR

Description:

Appendix K Small Break Summary Sheet Status: Current PRAIRIE ISLAND 2 NRP_LOCA-50.46_NRP_Base_Appendix_K_SBLOCA - 1.2 V.V PCT (°F)

Reference #

Note #

ANALYSIS-OF-RECORD 959 1,2 a

AOR + ASSESSMENTS PCT =

959.0 °F REFERENCES 1 LTR-LIS-08-158, Transmittal of Future Prairie Island Units 1 and 2 PCT Summaries, February 2008.

2 LTR-LIS-13-274, Prairie Island Units 1 and 2, 10 CFR 50.46 Summary Sheets for the Evaluation to Support the Unit 2 Installation of AREVA Model 56/19 Replacement Steam Generators (RSGs), June 2013.

NOTES:

(a) The Unit 1 AOR is applicable to Unit 2 with the RSGs installed.

Version: PRAIRIE ISLAND 2 NRP_LOCA-50.46_NRP_Base_Appendix_K_SBLOCA - 1.2 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved Page 8 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 7 of 9 LOCA Peak Cladding Temperature (PCT) Summary Plant Name:

PRAIRIE ISLAND 2 EM:

ASTRUM (2004)

AOR

Description:

Best Estimate Large Break Summary Sheet Status:

IFBA/Gad PRAIRIE ISLAND 2 NRP_LOCA-50.46_NRP_IFBA_GAD_ASTRUM - 1.5 V.V PCT (°F)

Reference #

Note #

ANALYSIS-OF-RECORD 1765 1

ASSESSMENTS*

Delta PCT

(°F)

Reference #

Note #

Reporting Year**

1.

Revised Heat Transfer Multiplier Distributions

-2 3

2013 2.

Error in Burst Strain Application 25 4

2013 3.

Evaluation of the Introduction of IFBA Fuel 0

2 2019 4.

Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown 227 5

(a),(b) 2012 AOR + ASSESSMENTS PCT =

2015 °F The licensee should determine the reportability of these assessments pursuant to 10 CFR 50.46.

    • The Reporting Year refers to the annual reporting year in which this assessment was included.

REFERENCES 1

WCAP-17783-P, Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Prairie Island Units 1 and 2 with Replacement Steam Generators Using ASTRUM Methodology, June 2013.

2 LTR-LIS-15-287, Rev. 1, Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting for the Revised Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown Evaluation and the Introduction of IFBA Fuel, September 2015.

3 LTR-LIS-13-366, Revision 1, Prairie Island Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions, August 2013.

4 LTR-LIS-14-50, Prairie Island Units 1 and 2 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction, January 2014.

5 LTR-LIS-12-414, Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown, September 2012.

Version: PRAIRIE ISLAND 2 NRP_LOCA-50.46_NRP_IFBA_GAD_ASTRUM - 1.5 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved Page 9 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Attachment to NSPM-LOCA-TM-A5-000001 Page 8 of 9 Version: PRAIRIE ISLAND 2 NRP_LOCA-50.46_NRP_IFBA_GAD_ASTRUM - 1.5 V.V 2022 Westinghouse Electric Company LLC All Rights Reserved NOTES:

(a) This evaluation credits peaking factor burndown, see Reference 5.

(b) The reporting text and line item originally identified for Unit 1 in Reference 5 is applicable to Unit 2 with RSGs.

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)

Page 10 of 11

Attachment to NSPM-LOCA-TM-A5-000001 Page 9 of 9 10 CFR 50.46 Reporting SharePoint Site Check:

EMs applicable to Prairie Island:

Realistic Large Break - ASTRUM (2004)

Appendix K Small Break - NOTRUMP 2021 Issues Transmittal Letter Issue Description None None Page 11 of 11

      • This record was final approved on 2/7/2022, 3:49:15 PM. (This statement was added by the PRIME system upon its validation)
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