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Westinghouse, 10 CFR 50.46 Annual Report for the AP1000 Plant Design
	ML23090A166
Person / Time
Site:	05200006
Issue date:	03/28/2023
From:	Harper Z; Westinghouse, Westinghouse
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	DCP_NRC_003347
	Download: ML23090A166 (1)
	v • d • e

Westinghouse Non-Proprietary Class 3

Westinghouse Electric Company 1000 Westinghouse Drive Cranberry Township, Pennsylvania, 16066 USA

U.S. Nuclear Regulatory Commission Direct tel: 412-374-5093 Document Control Desk Direct fax: 724-940-8505 11555 Rockville Pike e-mail: harperzs@westinghouse.com Rockville, MD 20852

Your Ref: Docket No.52-006 Our Ref: DCP_NR C_003347

March 28, 2023

Subject:

10 CFR 50.46 Annual Report for the AP1000 Plant Design

Pursuant to 10 CFR 50.46, Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors, Westinghouse Electric Company, LLC is submitting th is report to document emergency core cooling system (ECCS) evaluation model changes or errors for the 2022 Model Year (i.e., 01/01/2022 - 12/31/2022) that affect the peak cladding temperature (PCT) calculations for the AP1000 plant design.

As described below, two AP1000 analyses of record (AORs) are reported:

AP1000 Design Certification AOR:

On December 30th, 2011, the U.S. Nuclear Regulatory Commission certified an amendment to the Design Certification Rule for the AP1000 plant. As such, AP1000 Design Control Document (DCD) Revision 19 documents the AOR for th e AP1000 Design Certification. Th e limiting transient for the AP1000 Design Certification is the Best Estimate Large Break Loss-of-Coolant Accident (LBLOCA). Westingho use last provided an annual reporting letter to th e NRC in March 2022 (DCP_NRC_003346) which presented an estimated PCT of 2010°F for the LBLOCA evaluation. There are no new ECCS model changes that impact PCT for the 2022 model year.

The estimated PCT for LBLOCA remains at 2010°F and does not exceed the 10 CFR 50.46 (b)(1) acceptance criterion of 2200°F.

The summary of the PCT margin allocations and their bases for the AP1000 Design Certification AOR are provided in the Attachment 1.

AP1000 Vogtle Units 3 & 4 AOR:

In addition to the AOR for the AP1000 Design Ce rtification, the NRC has approved the AP1000 Core Reference Report (WCAP-17524-P-A), a generic topical which includes an ECCS reanalysis in the context of 10 CFR 50.46. The AOR contained in the Core Reference Report (CRR) has also been approved for incorporation into the Vogtle Units 3 & 4 licenses via NRC License Amendment 52. Westinghouse last provided an annual reporting letter to the NRC in March 2022 (DCP_NRC_003346) which presented an estimated PCT of 2046°F for the LBLOCA evaluation. There are no new ECCS model changes that impact the limiting LBLOCA PCT for AP1000 is a trademark or registered trademark of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved.

Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners

the 2022 model year. As such, the estimated PCT for LBLOCA is 2046°F and does not exceed the 10 CFR 50.46 (b)(1) acceptance criterion of 2200°F.

Additionally, changes as part of the Automatic Depressurization System (ADS) and Core Makeup Tank (CMT) design parameters changes included in LAR-19-009 constitute a reanalysis in the context of 10 CFR 50.46 for the small break loss of coolant accident (SBLOCA) analysis and have been approved for incorporation into the Vogtle Units 3&4 licenses via NRC License Amendments 176 (Unit 3) and 175 (Unit 4). Ther e are no new ECCS model changes that impact the limiting SBLOCA PCT for the 2022 model year. The estimated LBLOCA PCT continues to be the limiting estimated PCT following the SBLOCA reanalysis.

The summary of the PCT margin allocations and their bases for the AP1000 Vogtle Units 3 & 4 AOR are provided in the Attachment 2.

By copy of this letter, COL Holders and COL Applicants are hereby notif ied of any changes or errors in the AP1000 standard plant design PCT calculations as required by 10 CFR 50.46(a)(3)(iii). This letter contains site-specific evaluations for Vogtle Units 3 & 4.

Questions or requests for additional information related to content and preparation of this information should be directed to Westinghouse. Pl ease send copies of such questions or requests to the respective COL Holders and COL Applicants referencing the amended AP1000 Design Certification Rule for the AP1000 nuclear power plant. A representative for each COL Holder and COL Applicant is included on the cc: list of this letter.

Sincerely,

Zachary S. Harper Manager, Licensing Engineering

/Attachments

1. 10 CFR 50.46 Annual Report for the AP1000 Design Certification AOR, 2022 Model Year

2. 10 CFR 50.46 Annual Report for the AP1000 Vogtle Units 3 & 4 AOR, 2022 Model Year

Cc:

M. Dudek - U.S. NRCA. Zaremba - Duke/ProgressD. McDevitt - Westinghouse B. Smith - U.S. NRCS. Franzone - FPLM. Sheaffer - Westinghouse A. Chamberlain - SNC M. Yuan - WestinghouseM. Barca - Westinghouse J. Baker - SNCC. Zozula - WestinghouseM. Patterson - Westinghouse E. Grant - SNCM. Arnold - Westinghouse J. Douglass - SNCA. Schoedel - Westinghouse

10 CFR 50.46 Annual Report for the AP1000 Design Certification AOR, 2022 Model Year

Background

The Generalized Energy Deposition Model (GEDM) used within WCOBRA/TRAC is described in Section 8-6-2 of WCAP-12945-P-A [1] and Section 8 2 of WCAP-16009-P-A [2]. Non-conservation of the deposited energy was discovered to exist, whereby a very small fract ion of the redistributed energy was not being included in the core balance rods. The energy deposited to the hot rod and hot assembly was confirmed to be conserved and correct.

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 The error was qualitatively evaluated, and the nature of the error leads to an estimated peak cladding temperature impact of 0°F.

Reference(s)

1) WCAP-12945-P-A, Revision 2 Volume 1, and Revision 1 Volumes 2 - 5, Code Qualification Document for Best Estimate LOCA Analysis, March 199 8.

2) WCAP-16009-P-A, Revision 0, Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM), January 2005.

AOR

Description:

Best Estimate Large Break Summary Sheet Status: DCD

AP1000 AP1K_LOCA -50.46_AP1K_DCD_ASTRUM - 1.1 V.V

PCT (°F) Reference # Note #

ANALYSIS-OF-RECORD 1837 1

Delta PCT Reporting ASSESSMENTS* (°F) Reference # Note # Year**

1. Evaluation of Pellet Thermal 2012 Conductivity Degradation and 139 2 Peaking Factor Burndown

2. Revised Heat Transfer 2013 Multiplier Distributions 11 3

3. Error in Burst Strain Application 23 4 2013

AOR + ASSESSMENTS PCT = 2010.0 °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 APP-GW-GL-700, Revision 19, AP1000 Design Control Document, June 2011.

2 LTR-LIS 288, Inform ation Regarding the Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown Including Analysis Input Changes for AP1000 Large Break LOCA Analysis, June 2012.

3 LTR-LIS 357, AP1000 Plant 10 CFR 50.46 Report for Revised He at Transfer Multiplier Distributions, July 2013.

4 LTR-LIS 41, AP1000 Plant 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction, January 2014.

NOTES:

(a) None

Description:

Appendix K Small Break Summary Sheet Status: DCD

AP1000 AP1K_LOCA -50.46_AP1K_DCD_Appendix_K_SBLOCA - 1.1 V.V

PCT (°F) Reference # Note #

ANALYSIS-OF-RECORD 1370 1 (a)

Delta PCT Reporting ASSESSMENTS* (°F) Reference # Note # Year**

1. Adiabatic Heat-up Calculation 264 2 (a) 2010

AOR + ASSESSMENTS PCT = 1634.0 °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 APP-GW-GL-700, Revision 19, AP1000 Design Control Document, June 2011.

2 LTR-LIS 373, 10 CFR 50.46 Report for the Evaluation of AP1000 SBLOCA 10- inch Transient Adiabatic Heat-up Calculation, June 2010.

NOTES:

(a) This is an adiabatic heat-up calculated PCT.

10 CFR 50.46 Annual Report for the AP1000 Vogtle Units 3 & 4 AOR, 2022 Model Year

Background

The Generalized Energy Deposition Model (GEDM) used within WCOBRA/TRAC is described in Section 8-6-2 of WCAP-12945-P-A [1] and Section 8 2 of WCAP-16009-P-A [2]. Non-conservation of the deposited energy was discovered to exist, whereby a very small fract ion of the redistributed energy was not being included in the core balance rods. The energy deposited to the hot rod and hot assembly was confirmed to be conserved and correct.

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 The error was qualitatively evaluated, and the nature of the error leads to an estimated peak cladding temperature impact of 0°F.

Reference(s)

1) WCAP-12945-P-A, Revision 2 Volume 1, and Revision 1 Volumes 2 - 5, Code Qualification Document for Best Estimate LOCA Analysis, March 199 8.

2) WCAP-16009-P-A, Revision 0, Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM), January 2005.

© 2023 Westinghouse Electric Company LLC All Rights Reserved LOCA Peak Cladding Temperature (PCT) Summary Plant Name: Vogtle Unit 3 and Unit 4 Utility Name: Southern Nuclear Operating Company EM: ASTRUM (2004)

AOR

Description:

Best Estimate Large Break Summary Sheet Status: Current

Vogtle Unit 3 SV3_LOCA -50.46_SV3_Base_ASTRUM - 1.3 V.V

PCT (°F) Reference # Note #

ANALYSIS-OF-RECORD 1936 1 (a)

Delta PCT Reporting ASSESSMENTS* (°F) Reference # Note # Year**

1. Revised Heat Transfer 2 2013 Multiplier Distributions 11

2. Error in Burst Strain 3 2013 Application 23

3. Design Change Rebaseline 4,5 (b) 2018 Evaluation 54

AOR + ASSESSMENTS PCT = 2046.0 °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-17524-P-A, Revision 1, AP1000 Core Reference Report, May 2015.

2 LTR-LIS 357, AP1000 Plant 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions, July 2013.

3 LTR-LIS 41, AP1000 Plant 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction, January 2014.

4 LTR-LIS 393, Update to the Vogtle Units 3 & 4 LBLOCA and SBLOCA 10 CFR 50.46 PCT Summary Sheets for LAR -

79, November 2018.

5 ND-17-2074 (ML18029A243), Containment Pressure Analysis (LAR 043), December 2017. Approved by NRC November 7, 2018 as Amendments 147 (VEGP Unit 3) and 146 (VEGP Unit 4) (ML18289A742).

6 LTR-LIS 39, AP1000 Plant Suggested 10 CFR 50.46 Reporting Text and Updated LBLOCA PCT Summary Sheet for Evaluation of Reactor Coolant Pump (RCP) Design Changes, January 2017.

7 ND-18-1147 (ML18243A459), Reactor Coolant System (RCS) Flow Coastdown (LAR 025), August 2018. Approved by NRC February 25, 2019 as Amendments 155 (VEGP Unit 3) and 154 (VEGP Unit 4) (ML19038A450 ).

(a) Value contains 2°F bias for PCT sensitivity to PRHR isolation, per Reference 1 response to CRR -008, Table 2 and Table 15.6.5-8.

(b) The design change rebaseline evaluation used current code versions and accounts for design changes up to May 5, 2014 and plant model error corrections.

(c) The RCP design changes evaluation assesses the impact of DCP 5338 (APP -GW-GEE-5338), which is tied to DCP 4880 (APP-GW-GEE-4880). The evaluated changes include updated homologous curves and small changes to the pump rated conditions and rotor inertia.

© 2023 Westinghouse Electric Company LLC All Rights Reserved LOCA Peak Cladding Temperature (PCT) Summary Plant Name: Vogtle Unit 3 and Unit 4 Utility Name: Southern Nuclear Operating Company EM: NOTRUMP-AP AOR

Description:

Appendix K Small Break Summary Sheet Status: Current

Vogtle Unit 3 SV3_LOCA -50.46_SV3_Future_Appendix_K_SBLOCA - 1.3 V.V

PCT (°F) Reference # Note #

ANALYSIS-OF-RECORD 1099 1

AOR + ASSESSMENTS PCT = 1099.0 °F

REFERENCES 1 ND-19-1142 (ML19273A953), Automatic Depressurization System (ADS) and Core Makeup Tank (CMT) Design Parameters (LAR 009), September 2019. Approved by NRC March 11, 2020 as Amendments 176 (VEGP Unit 3) and 175 (VEGP Unit 4) (ML20049A721/ML20049A808).

NOTES:

(a) None

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