ML26037A210
| ML26037A210 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/03/2026 |
| From: | Samson Lee NRC/NRR/DORL/LPL4 |
| To: | Richardson M Pacific Gas & Electric Co |
| Lee S, NRR/DORL/LPL4 | |
| References | |
| EPID L-2025-LLA-0122 | |
| Download: ML26037A210 (0) | |
Text
From:
Samson Lee To:
Richardson, Michael
Subject:
Request for additional information: Diablo Canyon proposed revision to Technical Specification 3.7.12, Auxiliary Building Ventilation System (ABVS) (EPID: L-2025-LLA-0122)
Date:
Tuesday, February 3, 2026 2:22:00 PM
Background
By letter dated July 31, 2025, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25213A095), Pacific Gas and Electric, (PG&E, the licensee) submitted a license amendment request (LAR) that proposed changes to the technical specifications (TS) for the Diablo Canyon Power Plant, Units 1 and 2 (Diablo Canyon). The proposed LAR revises TS 3.7.12 by changing Condition Bs Completion Time from 7 days to 30 days.
Following its review, the U.S. Nuclear Regulatory Commission (NRC) staff determined that, to complete its review, it needs a response to its request for additional information (RAI) below. The NRC staff may have additional RAIs. The licensee staff and NRC staff held a draft RAI clarification call on February 3, 2026. The licensee staff requested, and NRC agreed, to an RAI response by March 3, 2026.
The NRC staff considers that timely responses to RAIs help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. Please note that if the licensee does not respond to this request by the agreed upon date or provide an acceptable alternate date, the NRC staff may deny the licensees application for amendment under the provisions of 10 CFR 2.108. If circumstances result in the need to revise the agreed upon response date, please contact Samson Lee, NRC Project Manager, at (301) 415-3168 or via email Samson.Lee@nrc.gov.
RAI Question 1 As part of its LAR, the licensee requested to extend a Completion Time for a Condition within TS 3.7.12, Auxiliary Building Ventilation System (ABVS).The proposed change revises the Completion Time from 7 days to 30 days.This Completion Time applies to Required Action B.1, Restore ABVS train to OPERABLE status, if Condition B, One ABVS train inoperable, were to occur.
As part of its evaluation, the NRC staff must ensure the licensee adequately explains why extending to a 30-day Completion Time is needed and that the extension will not compromise plant safety.As part of its LAR, the licensee provided the following as justification as to why the extension to 30 days is needed:
"The change in the ABVS Completion Time to 30 days will not result in routine use of an ABVS 30-day Completion Time during a cycle since operating experience has shown the current 7-day Completion Time is sufficient to complete on-line testing and the scope of on-line maintenance that is scoped into a 7-day maintenance outage. With a 30-day Completion Time, maintenance or modifications that currently could only be performed during an outage could be performed on-line. In addition, emergent complex required ABVS corrective maintenance (e.g., component repair or replacement) that requires greater than 7 days and up to 30 days could be performed on-line without a plant TS required shutdown or the need for emergency amendment activities that can impact plant personnel focus on restoring OPERABILITY of the ABVS."
In order to ensure the requirements of Title 10 of the Code of Federal Regulations (10 CFR)
Section 50.36, Technical specifications, are met, the NRC staff is requesting that the above justification is enhanced by providing examples and practices that confirm that extending the Completion Time to 30 days, and not a lesser duration (i.e., 14 or 21 days) is necessary.
Docket Nos. 50-275 and 50-323