ML24157A054

Audit Summary in Support of License Amendment Request for Proposed Reclassification of Low Head Safety Injection Flow Instrumentation Related to Regulatory Guide 1.97

ML24157A054
Person / Time
Site:	Surry
Issue date:	06/13/2024
From:	Klos L Plant Licensing Branch II
To:	Carr E Virginia Electric & Power Co (VEPCO)
Klos, J
References
EPID L-2023-LLA-0115
Download: ML24157A054 (7)

Text

June 13, 2024

Eric S. Carr President - Nuclear Operations and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

SURRY POWER STATION, UNIT NOS. 1 AND 2 - AUDIT

SUMMARY

IN SUPPORT OF LICENSE AMENDMENT REQUEST FOR PROPOSED RECLASSIFICATION OF LOW HEAD SAFETY INJECTION FLOW INSTRUMENTATION RELATED TO REGULATORY GUIDE 1.97 (EPID L-2023-LLA-0115)

Dear Eric S. Carr:

By letter dated August 10, 2023, and as supplemented by letters dated April 15 and May 20, 2024 Agencywide Documents Access and Management System (ADAMS), Accession No. ML23226A186, ML24108A181, and ML24141A251, respectively, Virginia Electric and Power Company (Dominion Energy Virginia) submitt ed a license amendment request (LAR) to amend the license and technical specifications (TSs) for Surry Power Station (Surry), Units 1 and 2, Renewed Facility Operating License No. DPR-32 and DPR-37, respectively. The proposed amendments would revise the Surry TS to reclassify Low Head Safety Injection (LHSI) flow instrumentation and accident monitoring instrument ation related to Regulatory Guide (RG) 1.97, Revision 3 (ML003740282), Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants variable from a Type D category variable to a Type 1 variable.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the licensee's submittal and determined that a regulatory audit would assist in the timely completion of the licensing review process. The NRC staff issued a regulatory audit plan on March 21, 2024 (ML24078A264).

The NRC staff conducted the regulatory audit from April 3, 2024 to May 31, 2024. The results of the regulatory audit will be used by the NRC staff to finalize requests for additional information.

The audit summary report is provided as an enclosure to this letter.

E. Carr

If you have any questions, please contact me by telephone at 301-415-5136 or by email to John.Klos@nrc.gov.

Sincerely,

/RA/

L. John Klos, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos. 50-280 and 50-281

Enclosure:

Audit Summary

cc: Listserv

AUDIT

SUMMARY

LICENSE AMENDMENT REQUEST FOR RECLASSIFICATION

OF LOW HEAD SAFETY INJECTION FLOW INSTRUMENTATION

RELATED TO REGULATORY GUIDE 1.97

DOMINION ENERGY VIRGINIA

SURRY POWER STATION, UNITS 1 AND 2

DOCKET NOS. 50-280 AND 50-281

1.0 BACKGROUND

By letter dated August 10, 2023, and as supplemented by letters dated April 15 and May 20, 2024 Agencywide Documents Access and Management System (ADAMS), Accession No. ML23226A186, ML24108A181, and ML24141A251, respectively, Virginia Electric and Power Company (Dominion Energy Virginia) submi tted a license amendment request (LAR) to amend the license and technical specifications (TSs) for Surry Power Station (Surry), Units 1 and 2, Renewed Facility Operating License No. DPR-32 and DPR-37, respectively. The proposed amendments would revise the Surry TS to reclassify Low Head Safety Injection (LHSI) flow instrumentation and accident m onitoring instrumentation related to Regulatory Guide (RG) 1.97, Revision 3 (ML003740282), Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants variable from a Type D category variable to a Type 1 variable.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the licensee's submittal and determined that a regulatory audit would assist in the timely completion of the licensing review process. The NRC staff issued the regulatory audit plan on March 21, 2024 (ML24078A264) which detailed the logistics, scheduling and audit request items in the plans attachment.

The NRC staff conducted the regulatory audit from April 3, 2024 to May 31, 2024. The results of the regulatory audit will be used by the NRC staff to finalize requests for additional information (RAls), as necessary.

The regulatory audit was performed consistent with NRC Office of Nuclear Reactor Regulation (NRR) Office Instruction LIC-111, Revision 1, "Regulatory Audits" (ML19226A274).

Enclosure

2.0 AUDIT ACTIVITIES AND OBSERVATIONS

The NRC audit team consisted of NRC staff and Section 3.0 of this audit summary lists the individuals that took part in or attended the audit.

The regulatory audit was conducted from April 3, 2024 to May 31, 2024. The NRC audit team used an internet-based portal provided by the licensee to review non-docketed information related to the application. Audit meetings via Teams with the licensee were held on April 18, and May 9, 2024 to facilitate technical discussions of audit questions and items that may require submission on the docket.

Technical discussions were focused on the following major areas:

Gain a better understanding of the detailed calculations, analyses, and bases underlying the LARs and confirm the staffs understanding of the LARs.

Gain a better understanding of plant design features and implications for the LAR request.

Identify any information needed to enable the staffs evaluation of whether the proposed changes challenge design-basis functions or adversely affect the capability or capacity of plant equipment to perform design-basis functions.

Identify the NRC-approved methodologies used for the analyses of loss-of-coolant accident (LOCA), material & equipment (M&E) release in containment, LOCA containment response (i.e., transient containment pressure, vapor temperature, and sump water temperature).

Identify the key inputs and assumptions used in the analyses, confirming the inputs are sufficient for determining the limiting transient net positive suction head (NPSH), and understanding the justification for any conservatisms applied.

Determine the output results of the analyses and to specifically evaluate containment pressure, vapor temperature, and sump water temperature responses, including their peak values calculated.

Identify the available NPSH and required NPSH values with single LHSI pump operating at high (unthrottled) flow and at the proposed design (throttled) flow.

Identify the values of containment accident pressure (CAP), if used, in determining the available NPSH at various flows conditions to understand indicating parameters that may be below, or above, the vapor pressure at the corresponding sump water temperature.

Provide the impact of the lesser flow, due to the proposed lowered flow from the single LHSI pump, on the long-term decay heat removal and the containment cooling temperature and pressure profile.

There were no open items from audit discussions and no deviations from the audit plan.

Documents that were provided as part of the audit that were reviewed by the NRC staff are listed in Section 4.0 of this audit summary.

By letter dated May 20, 2024, (ML24141A251) the licensee provided a supplement that details the technical discussion related to the audit questions/discussions that were held on April 18, and May 9, 2024. At the teleconferences the audit questions/discussions points - which were addressed by the licensees docketed supplement-were;

Discuss identify the NRC-approved methodologies used for the analyses of LOCA M&E release in containment, LOCA containment response, i.e., transient containment pressure, vapor temperature, and sump water temperature.

Identify the key inputs and assumptions used in the analyses, confirm that the inputs are conservatively biased for determining the limiting transient NPSH. Justify any conservatisms applied to this analysis.

Document the results of the analyses, specifically the containment pressure, vapor temperature, and sump water temperature responses, including their peak values.

Identify the available NPSH and required NPSH values associated with single LHSI pump operating at high (unthrottled) flow and at the proposed design (throttled) flow.

Identify the values of CAP, if used, in determining the available NPSH at the flows in item (d) stating if it is below or above the vapor pressure at the sump water temperature.

Discuss the impact of the lesser flow on the long-term decay heat removal and the containment cooling temperature and pressure profile.

The NRC staff reviewed the licensees supplement to assess if any additional information was needed and determined that no additional information would be needed to complete its review of the subject LAR.

3.0 AUDIT PARTICIPANTS

The following table identifies the NRC audit team members

Name E-mail Review Area (Organization)

John Klos John.Klos@nrc.gov Plant Licensing Branch LPL II-1 (LPL2-1)

Ahsan Sallman Ahsan.Sallman@nrc.gov Nuclear Systems Performance Branch (SNSB)

4.0 DOCUMENTS REVIEWED

The licensee provided an extensive list of supporting documents (e.g., analyses, calculations, reports, drawings, and procedures) on the Surry document portal available during the audit period. Below lists the documents available on the portal that the NRC audit team reviewed during the audit.

WCAP-14083, Westinghouse LOCA M&E release, May 1994 LTR-CRA-07-88, Final Surry LOCA M&E reanalysis to address issues, Dec 7, 2007 ETE-NAF-2020-0105, Implementation of PWROG-17034-P-A for Surry, Rev 0, July 29, 2021 Calculation SM-1474-0-B, GOTHIC Input for Containment Analysis, Rev 0, Aug 29, 2013 Calculation SM-1475-0-I, Containment Analysi s for LHSI Throttling, Rev 0, May 20, 2021 Calculation SM-1475-0-J, Containment Analysis for TCOA on LHSI Unthrottling, Rev 0, Aug 25, 2022 Calculation SM-1476-1-J, Revised LHSI and RS NPSH Analysis Supporting Recapture of LHSI NPSH Margin, Rev 1, October 14, 2021

ML24157A054 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DSS/SNSB/(A)BC NAME JKlos KGoldstein RBeaton for PSahd DATE 6/4/2024 06/05/2024 06/06/2024 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL2-1/PM NAME MMarkley JKlos DATE 6/13/2024 6/13/2024