ML25352A188
| ML25352A188 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/19/2025 |
| From: | Samson Lee Plant Licensing Branch IV |
| To: | Gerfen P Pacific Gas & Electric Co |
| Lee S, 301-415-3158 | |
| References | |
| EPID L-2025-LLA-0139 | |
| Download: ML25352A188 (0) | |
Text
December 19, 2025 Ms. Paula Gerfen Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 56, Mail Code 104/6 Avila Beach, CA 93424
SUBJECT:
DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2 -
REGULATORY AUDIT PLAN IN SUPPORT OF LICENSE AMENDMENT REQUEST TO ADOPT EMERGENCY ACTION LEVEL SCHEME PURSUANT TO NEI 99-01, REVISION 7, DEVELOPMENT OF EMERGENCY ACTION LEVELS FOR NON-PASSIVE REACTORS (EPID L-2025-LLA-0139)
Dear Ms. Gerfen:
By letter dated August 27, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25239B075), Pacific Gas and Electric Company (the licensee) submitted a license amendment request (LAR) for Diablo Canyon Nuclear Power Plant, Units 1 and 2 (Diablo Canyon). The proposed amendments would revise the Emergency Action Levels (EALs) to reflect changes contained in Nuclear Energy Institute (NEI) 99-01, Revision 7, Development of Emergency Action Levels for Non-Passive Reactors, dated September 2024 (ML24274A312).
The U.S. Nuclear Regulatory Commission (NRC) staff will conduct a virtual regulatory audit to support its review of the LAR. A regulatory audit is a planned activity that includes the examination and evaluation of information that is not docketed. The audit will be conducted to enhance the NRC staffs understanding of the request and to identify information that may be needed on the docket to support our regulatory findings.
In accordance with the enclosed audit plan and requests, the audit team will review documentation and information that support the proposed amendments. For efficiency, the team requests that you establish a secure online portal for remote access to this material. The team will also interview the licensees subject matter experts using video-and teleconferencing.
If you have any questions, please contact me by telephone at 301-415-3168 or by email to Samson.Lee@nrc.gov.
Sincerely,
/RA/
Samson S. Lee, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323
Enclosure:
Audit Plan cc: Listserv
Enclosure REGULATORY AUDIT PLAN IN SUPPORT OF LICENSE AMENDMENT REQUEST TO ADOPT EMERGENCY ACTION LEVEL SCHEME PURSUANT TO NEI 99-01, REVISION 7, DEVELOPMENT OF EMERGENCY ACTION LEVELS FOR NON-PASSIVE REACTORS PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-275 AND 50-323 1.0
Background
By letter dated August 27, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25239B075), Pacific Gas and Electric Company (the licensee) submitted a license amendment request (LAR) for Diablo Canyon Nuclear Power Plant, Units 1 and 2 (Diablo Canyon). The proposed amendments would revise the Emergency Action Levels (EALs) to reflect changes contained in Nuclear Energy Institute (NEI) 99-01, Revision 7, Development of Emergency Action Levels for Non-Passive Reactors, dated September 2024 (ML24274A312).
The U.S. Nuclear Regulatory Commission (NRC) staff in the Office of Nuclear Security and Incident Response (NSIR) has initiated its review of the LAR in accordance with Office of Nuclear Reactor Regulation (NRR) Office Instruction LIC-101, Revision 6, License Amendment Review Procedures, (ML23236A583, package). The NRC staff notes that this is the first of a number of industry applications to be submitted based on NEI 99-01, Revision 7.
2.0 Regulatory Audit Basis A regulatory audit is a planned activity to examine and evaluate information that provides the technical basis for actions related to a license or regulation. An audit allows the NRC staff to gain insights to the licensees processes and procedures. In the case of a LAR, the NRC staff can clarify its understanding of the request, verify the information submitted, and identify additional information that the staff needs to make a licensing or regulatory decision. Information that the NRC staff relies upon to make a safety determination or decision must be submitted on the docket.
The NRC staff will perform this audit to support its evaluation of whether the licensees requests can be approved per Title 10 of the Code of Federal Regulations Section 50.90, Application for amendment of license, construction permit, or early site permit. It will be conducted in accordance with NRR LIC-111, Regulatory Audits, Revision 2, dated December 30, 2024 (ML24309A281). The audit will help the NRC staff to understand the licensees proposed programs for implementing and applying NEI 99-01, Revision 7.
3.0 Regulatory Audit Scope The audit team will review the licensees Emergency Plan (E-Plan) EAL scheme and supporting documentation and information. The audit team will use this information to determine if the licensee needs to submit any additional information on the docket to support the NRC staffs safety evaluation.
The audit team will view the documentation and information that provide the technical support for the LAR. The scope of the NRC staffs audit will include the following subjects:
Understand how the licensees proposed program conforms to NEI 99-01, Revision 7.
Confirm the NRC staffs understanding of the LAR and gain a better understanding of the detailed calculations, analyses, and bases on which it is based.
Gain a better understanding of plants E-Plan and implications for the LAR.
Follow up on items identified in the September 29, 2025, letter on NRC acceptance review (ML25269A071) and in the NRC staff presentation at the June 4, 2025, public meeting (ML25147A147).
Information needed to support a safety finding or licensing decision may already be docketed, which can be determined during the audit. Otherwise, it must be submitted under oath and affirmation. The licensee may supplement the LAR with this information. Alternatively, the licensee may respond to a formal request for additional information (RAI). If needed, RAIs will be developed and transmitted separately in accordance with NRR Office Instruction LIC-115, Revision 1, Processing Requests for Additional Information, dated August 5, 2021 (ML21141A238).
4.0 Information and Other Material Necessary for the Regulatory Audit The NRC staff will request information and interviews throughout the audit period. The NRC staff will use an audit items list to identify the information to be audited (e.g., methodology, process information, and evaluations) and the subjects of requested interviews and meetings.
The NRC staff will add new audit items and audit questions during the audit process.
The NRC staff requests that the licensee have the information referenced in the attachment of this audit plan available and accessible for the NRC staffs review via a web portal within 2 weeks of the date of this audit plan. As additional or supplemental information is requested, it should be available and accessible within 1 week of the date of the NRC staffs notification to the licensee of the new requests. The NRC staff requests that the licensee notify the review team when an audit item is added to its portal by sending an email to the NRC licensing project manager.
The NRC staff acknowledges and will observe appropriate handling and protection of proprietary information made available for the audit. The NRC staff will not remove non-docketed information from the audit site or web portal.
5.0 Audit Team The following table identifies the NRC/NSIR audit team members and their respective organization:
Name Email Organization Jeffrey Herrera (Lead)
Jeffrey.Herrera@nrc.gov Reactor Licensing Branch (RLB)
Keith Miller Keith.Miller@nrc.gov RLB Kenneth Mott Kenneth.Mott@nrc.gov RLB 6.0 Logistics The audit will be conducted remotely via a secure, online portal, established by the licensee to present supporting documentation and calculations. In addition to the review of documents made available on the portal, the NRC staff will interview the licensees subject matter experts, virtually (by telephone and videoconference). The audit will begin within 2 weeks of the date of this audit plan and last through April 2026. The NRC staff will establish a schedule of audit meetings as appropriate (e.g., a single, multi-day audit meeting with supplemental audit meetings as needed) on mutually agreeable dates and times.
At the meetings, the licensee is to discuss information needs and questions arising from the NRC staffs review of the application and other material reviewed during the audit. The NRC project manager will inform the licensee of audit meeting dates when they are established, including the date of an audit kick-off meeting.
7.0 Special Requests The following conditions associated with the online portal should be maintained while the NRC staff on the audit team have access to the online portal:
The online portal will be password-protected, and separate passwords will be assigned to each member of the audit team.
The online portal will prevent the NRC participants from printing, saving, downloading, or collecting any information directly from the online portal.
The licensee should provide username and password information directly to the NRC staff on the audit team listed above. The NRC project manager will provide the licensee the names and contact information of the NRC staff who are added to the audit team. All other communications should be coordinated with the NRC project manager. The NRC project manager will inform the licensee via routine communications when the NRC staff no longer needs access to the portal.
No data accessed by the audit team members will be retained by the NRC following the conclusion of the audit.
8.0 Deliverables The NRC staff will develop any RAIs, as needed, in accordance with NRR LIC-115 and issue such RAIs independent of audit-related correspondence. At the end of the audit, the NRC staff will conduct an exit meeting to inform the licensee of the outcome of the audit. The NRC staff will issue an audit summary report within 90 days of the audit exit.
Audit Items List ITEM REQUESTS 1
Technical justification for the site-specific changes to Appendix D - Emergency Action Level Technical Basis Manual:
- a. the front-sections (e.g., section 3.0, Guidance On Making Emergency Classifications);
- b. section 5.0, Definitions, Acronyms & Abbreviations; and,
- c. section 7.1 - Attachment 1, Emergency Action Level Technical Basis.
Provide the information in the same format as to what was done for the EALs (Difference/Deviation Matrix with basis/justification).
2 An example of Diablo Canyon EAL Wallboards for the proposed changes. Wall Board (to check layout and logic).
3 Documentation to confirm that all the applicable calculations for instrumentation values supporting adoption of NEI 99-01, Revision 7 are the same as those approved for Revision 6, or to provide the applicable revised calculations. For those values that have been changed, provide justification for the change and the associated engineering document or calculation.
4 Documentation or evidence that confirms the State and local officials have discussed and agreed upon the proposed changes for the EAL scheme transition from the current NEI 99-01, Revision 6 to Revision 7.
ML25352A188 NRR-106 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NSIR/DPR/RLB/BC NAME SLee PBlechman (SLent for)
JQuichocho DATE 12/18/2025 12/18/2025 12/17/2025 OFFICE NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME TNakanishi (MMahoney for) SLee DATE 12/19/2025 12/19/2025