ML25076A659
| ML25076A659 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 03/21/2025 |
| From: | Walter Kirchner Advisory Committee on Reactor Safeguards |
| To: | David Wright NRC/Chairman |
| Howard K | |
| Shared Package | |
| ML25084A182 | List: |
| References | |
| Download: ML25076A659 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 Honorable David A. Wright Chairman U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
REPORT ON THE SAFETY ASPECTS OF THE SUBSEQUENT LICENSE RENEWAL APPLICATION REVIEW FOR THE VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1
Dear Chairman Wright:
During the 723rd meeting of the Advisory Committee on Reactor Safeguards (ACRS), March 5 through March 6, 2025, we completed our review of the subsequent license renewal (SLR) application for the Virgil C. Summer Nuclear Station, Unit 1 (VCSNS), and the associated safety evaluation report prepared by NRC staff. Our review considered actions by the Dominion Energy South Carolina, Inc. (DESC), to extend the license for VCSNS by a subsequent period of 20 years beyond the currently approved 60 years of licensed operation. During this review, we had the benefit of discussions with representatives of the NRC staff and DESC. We also had the benefit of the referenced documents. This report fulfills the requirement of Title 10 of the Code of Federal Regulations (10 CFR) Section 54.25 that the ACRS review and report on all license renewal applications.
CONCLUSION AND RECOMMENDATION 1.
The programs and commitments made by DESC to manage age-related degradation provide confidence that the VCSNS can be operated in accordance with its current licensing basis for the subsequent period of extended operation (SPEO) without undue risk to the health and safety of the public.
2.
The DESC application for the SLR of the operating license for VCSNS should be approved.
BACKGROUND The VCSNS, a single unit generating station in Jenkinsville, South Carolina, is a pressurized water reactor with licensed output of 2,900 megawatts thermal (MWt). The Nuclear Regulatory Commission (NRC) issued the initial operating license on November 12, 1982. In this application, DESC requests renewal of the operating license for an additional 20 years beyond the expiration of their current license in 2042. The license would be extended to August 6, 2062.
March 21, 2025
David A. Wright DISCUSSION The DESC submitted an SLR application for VCSNS in August 2023. The DESC applied lessons learned from previous applications, requests for additional information, and internal aging management program (AMP) experience in preparation of their application. An experienced multidisciplinary team of corporate, site, and consultant personnel were assembled to develop the SLR application. The DESC followed the guidance in Generic Aging Lessons Learned Report for Subsequent License Renewal (GALL-SLR), and the Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants (SRP-SLR),
resulting in a thorough SLR application. It is worth noting that this is the third SLR application developed by Dominion Energy Inc, the parent company of DESC.
The DESC has been making improvements in the VCSNS facility informed by equipment performance monitoring. The following describes significant modifications and upgrades that have been made to VCSNS since initial license renewal. Mechanical fluid system modifications include: an ongoing fire protection piping and valve replacement campaign; service water chemical treatment was optimized to improve management of corrosion; a cured-in-place liner was installed in the emergency feedwater/service water system; and the emergency diesel generator fuel oil piping was upgraded. Electrical and instrument and controls modifications include replacement of the main transformer and installation of digital electro-hydraulic controls.
Other operational modifications and improvements include mitigation of cavitation in the service water system and replacement of safety-related chillers. These improvements to VCSNS provide evidence of a strong commitment by DESC to maintain the safe and reliable operation of the station.
One of the most notable technical issues that DESC has addressed for SLR involves primary shield wall fluence levels. The DESC has committed to more frequent inspections of reactor vessel supports based on conservative estimates of fluence and gamma dose values for portions of the primary shield wall structural concrete supporting the reactor vessel and associated nuclear steam supply system supports. Although no consequential degradation has been detected, these more frequent inspections will enhance monitoring for adverse conditions in this area.
Another important technical issue involves reliability of the emergency diesel generators. In 2022, the A emergency diesel generator failed during surveillance testing. The direct cause of the failure was a circumferential crack on a portion of the fuel oil piping. A root cause evaluation revealed other organizational and equipment issues. The DESC made changes to their corrective action program and plant health process to implement a corporate Preventive Culture Model. This was in addition to improvements in the fuel oil piping configuration. Since the implementation of corrective actions, all monthly and periodic emergency diesel generator surveillance tests have been satisfactory.
The DESC will implement 49 AMPs for SLR, comprised of 40 existing programs and 9 new programs. Of the new programs, all are consistent with the GALL-SLR report. Of the 40 existing programs, 13 are consistent with the GALL-SLR report, 27 have enhancements and/or allowed exceptions, and none are plant specific. The NRC staff found the programs, including those with enhancements and exceptions, to be acceptable.
The DESC has demonstrated the effectiveness of their programs to maintain material condition, sustain system and equipment performance, and identify and implement improvements to ensure facility safety and reliability. Commitments within the SLR application and in DESCs
David A. Wright responses to the NRC staff audits and inspections provide confidence that these programs will be implemented effectively throughout the SPEO. The detailed elements of the AMPs and related commitments are documented in the proposed Updated Final Safety Analysis Report supplement and will be managed through DESCs commitment tracking program.
The NRC staff reviewed DESCs application for SLR in accordance with the GALL-SLR and the SRP-SLR guidance documents. Conformance with this guidance provides the basis for a staff conclusion that an application for a subsequent license renewal of 20 additional years beyond the approved license for 60 years will afford no undue risk to the public throughout the SPEO.
In the safety evaluation report, NRC staff documented their review of the SLR application, additional information submitted by DESC, and information obtained through audits, inspections, and responses to requests for additional information. The NRC staff conducted two regulatory audits in 2023 and 2024 on the technical details of the SLR application. These audits included plant specific operating experience; irradiation of select structures and components; and electrical components. Phase I and Phase II inspections were completed in November 2021 and February 2022, respectively. These activities evaluated the completeness of the structures, systems, and components identified within the scope of the VCSNS SLR program, the suitability and adequacy of the aging management review, and the acceptability of the plant-specific time-limited aging analyses. There were no safety significant findings identified during the corresponding inspections and audits. The new programs incorporated in this application augment the current facility monitoring and maintenance processes in place at VCSNS. It is reasonable to conclude that the intended safety functions of the systems placed under the AMP programs will be maintained consistent with the VCSNS current licensing basis for the SPEO, as required by 10 CFR 54.21(a)(3). The NRC staff's extensive and detailed review of the SLR application, documented in the safety evaluation report, identified no open or confirmatory items. We concur with the NRC staffs safety evaluation.
SUMMARY
We conclude that the DESC application for the VCSNS subsequent license renewal meets the requirements described in 10 CFR 54.29(a)(1) and (a)(2). The programs and commitments made by DESC to manage age-related degradation provide confidence that VCSNS can be operated in accordance with its current licensing basis for the SPEO without undue risk to the health and safety of the public. The DESC application for the SLR of the operating license for VCSNS should be approved.
We are not requesting a formal response to this letter report.
Sincerely, Walter L. Kirchner Chairman Halnon, Gregory signing on behalf of Kirchner, Walter on 03/21/25
David A. Wright REFERENCES 1.
Dominion Energy South Carolina, Inc., Virgil C. Summer Nuclear Station Application for Subsequent License Renewal, August 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23233A172).
2.
U.S. Nuclear Regulatory Commission, Safety Evaluation Related to the Subsequent License Renewal of Virgil C. Summer Nuclear Station, Unit 1, January 2025 (ADAMS Accession No. ML25021A228).
3.
U.S. Nuclear Regulatory Commission, Virgil C. Summer Nuclear Station Unit 1 Report for the Aging Management Audit Regarding the Subsequent License Renewal Application Review (EPID No. L-2023-SLR-0003), June 25, 2024 (ADAMS Accession No. ML24177A138).
4.
U.S. Nuclear Regulatory Commission, Virgil C. Summer Nuclear Station Unit 1-Limited Scope Aging Management Audit Report Regarding the Subsequent License Renewal Application Review, January 17, 2025 (ADAMS Accession No. ML25007A234).
5.
U.S. Nuclear Regulatory Commission, NRC NUREG-2192, Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants, July 2017 (ADAMS Accession No. ML17188A158).
6.
U.S. Nuclear Regulatory Commission, Virgil C. Summer Nuclear Station Unit - NRC Inspection Report 05000395/2022010, March 10, 2022 (ADAMS Accession No. ML22069B079).
7.
U.S. Nuclear Regulatory Commission, NRC NUREG-1801, Generic Aging Lessons Learned (GALL) Report, Revision 2, December 2010 (ADAMS Accession No. ML103490041).
8.
U.S. Nuclear Regulatory Commission, NRC NUREG-2191, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, Volume 1, July 2017 (ADAMS Accession No. ML17187A031).
9.
U.S. Nuclear Regulatory Commission, NRC NUREG-2191, Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, Volume 2, July 2017 (ADAMS Accession No. ML17187A204).
- 10. U.S. Nuclear Regulatory Commission, NRC Regulatory Guide 1.188, Standard Format and Content for Application to Renew Nuclear Power Plant Operating Licenses, Revision 1, September 2005 (ADAMS Accession No. ML051920430).
- 11. U.S. Nuclear Regulatory Commission, NRC NUREG-2192, Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants, July 2017 (ADAMS Accession No. ML17188A158).
- 12. U.S. Nuclear Regulatory Commission, NRC NUREG-2221, Technical Bases for Changes in the Subsequent License Renewal Guidance Documents NUREG-2191 and NUREG-2192, December 2017 (ADAMS Accession No. ML17362A126).
David A. Wright 13. U.S. Nuclear Regulatory Commission, NRC NUREG-2222, Disposition of Public Comments on the Draft Subsequent License Renewal Guidance Documents NUREG-2191 and NUREG-2192, December 2017 (ADAMS Accession No. ML17362A143).
- 14. Nuclear Energy Institute, Industry Guideline for Implementing the Requirements of 10 CFR Part 54 for Subsequent License Renewal (NEI 17-01), March 2017 (ADAMS Accession No. ML17339A599).
- 15. Nuclear Energy Institute, NEI 14-12, Aging Management Program Effectiveness, December 31, 2014 (ADAMS Accession No. ML15090A665).
- 16. U.S. Nuclear Regulatory Commission, Virgil C. Summer SLRA Safety Evaluation Revision 1 and Transmittal Letter, February 28, 2025 (ADAMS Package No. ML25059A003).
David A. Wright
SUBJECT:
REPORT ON THE SAFETY ASPECTS OF THE SUBSEQUENT LICENSE RENEWAL APPLICATION REVIEW FOR THE VIRGIL C. SUMMER NUCLEAR STATION, UNIT 1 Accession No: ML25076A659 Publicly Available (Y/N): Y Sensitive (Y/N): N If Sensitive, which category?
Viewing Rights:
NRC Users or ACRS only or See restricted distribution OFFICE ACRS SUNSI Review ACRS ACRS ACRS ACRS NAME KHoward KHoward LBurkhart RKrsek MBailey WKirchner (GHalnon for)
DATE 03/18/25 03/18/25 03/20/25 03/20/25 03/21/25 03/21/25 OFFICIAL RECORD COPY March 21, 2025