DCL-23-121, Supplement to License Amendment Request 23-03, Revision to Technical Specification3.7.8, Auxiliary Saltwater System
| ML23320A312 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/16/2023 |
| From: | Petersen D Pacific Gas & Electric Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| DCL-23-121 | |
| Download: ML23320A312 (1) | |
Text
.. Pac11ic Gas and
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.~ _ Electric Company" PG&E Letter DCL-23-121 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Diablo Canyon Unit 2 Docket No. 50-323, OL-DPR-82 Supplement to License Amendment Request 23-03 Dennis B. Petersen Station Director Diablo Canyon Power Plant Mail code 104/5/502 P.O. Box 56 Avila Beach, CA 93424 805.545.4022 Dennis.Petersen@pge.com 10 CFR 50.91 Revision to Technical Specification 3.7.8, "Auxiliary Saltwater (ASW) System" Reference 1: PG&E Letter DCL-23-120, "License Amendment Request 23-03 Revision to Technical Specification 3.7.8, 'Auxiliary Saltwater (ASW)
System,"' dated November 14, 2023 (ADAMS Accession No. ML23319A204).
2: NRC email dated November 15, 2023
Dear Commissioners and Staff:
Pursuant to 10 CFR 50.91, Pacific Gas and Electric Company (PG&E) submitted Reference 1 that requested a proposed amendment to Facility Operating License No. DPR-82 for Unit 2 of the Diablo Canyon Power Plant to revise DCPP Technical Specification 3.7.8, "Auxiliary Saltwater (ASW) System." In Reference 2, the staff requested additional information on the exigent basis circumstances and impact of the ASW 2-2 pump replacement on the plant's electrical loads. The Enclosure to this letter contains the additional information requested by the staff.
PG&E makes no regulatory commitment (as defined by NEI 99-04) in this letter.
This letter includes no revisions to existing regulatory commitments.
Pursuant to 10 CFR 50.91, PG&E is sending a copy of this letter to the California Department of Public Health.
If you have any questions or require additional information, please contact James Morris, Regulatory Services Manager, at 805-545-4609.
A me m be r of the STARS (Strategic Teaming and Resource Sharing)
Alli an c e Cal laway
- Diablo Ca n yo n
- Pa lo Verde
- Wo lf Creek
Document Control Desk Page 2 PG&E Letter DCL-23-121 I state under penalty of perjury that the foregoing is true and correct.
Sincerely, Dennis B. Petersen Station Director Executed on:
kjse/ SAPN 51201169 Enclosure Date cc:
Diablo Distribution cc/enc: Anthony Chu, Branch Chief, California Dept of Public Health Mahdi 0. Hayes, NRC Senior Resident Inspector Samson S. Lee, NRR Project Manager Siva P. Lingam, NRR Project Manager John D. Monninger, NRC Region IV Deputy Administrator A
member of the STARS (Strategic Teaming and Resou rce Sharing)
Al li a nce Callaway
- Dia b lo Ca nyon
- Palo Ve rd e
- Wo lf Creek
Enclosure PG&E Letter DCL-23-121 Supplement to License Amendment Request 23-03 Revision to Technical Specification 3.7.8, "Auxiliary Saltwater (ASW) System" In PG&E Letter DCL-23-120, "License Amendment Request 23-03 Revision to Technic;_al Specification 3.7.8, 'Auxiliary Saltwater (ASW) System,"' -dated November 14, 2023 (ADAMS Accession No. ML23319A204), pursuant to 10 CFR 50.91, Pacific Gas and Electric Company (PG&E) requested a proposed amendment to Facility Operating License No. DPR-82 for Unit 2 of the Diablo Canyon Power Plant (DCPP) to revise the DCPP Technical Specification 3.7.8, "Auxiliary Saltwater (ASW) System." The proposed amendment would provide a one-time 144-hour completion time to support replacement of DCPP Unit 2 ASW Pump 2-2 beginning the week of December 11, 2023. The need to replace the ASW Pump 2-2 motor occurred on an emergent basis due to indication of a potential degraded motor bearing. The ASW Pump 2-2 motor is currently OPERABLE but trends in bearing performance indicate that OPERABILITY could be impacted prior to the next scheduled Unit 2 refueling outage in April 2024.
The NRC staff requested additional information on the exigent basis circumstances and impact of the ASW 2-2 pump motor replacement on the plant's electrical loads.
Exigent Basis Circumstances As stated on Page 5 of PG&E Letter DCL-23-120, an ASW Pump 2-2 oil sample was collected on August 21, 2023, by maintenance personnel that exhibited darker than normal oil. The associated analysis of the oil sample taken on August 21, 2023, was received on September 24, 2023, that indicated a slight increase in particulate count and recommended resuming bi-weekly oil samples along with drain and flush recommendations.
The next ASW Pump 2-2 oil sample was taken on October 23, 2023, per process. The associated analysis that was subsequently received on October 27, 2023, indicated a further step change increase in particulate count that warranted consideration of additional prudent measures. In consideration of the step change increase in ASW Pump 2-2 particulate count identified in the analysis received on October 27, 2023, the team of DCPP Engineering, Maintenance, and Operations personnel concluded that proactively replacing the ASW Pump 2-2 motor at the next practicable occasion would offer the optimal desired reliability for the ASW system.
In accordance with the 10 CFR 50.65 Maintenance Rule, DCPP procedures require management of plant risk during on-line maintenance activities. As part of the plant risk management process, weekly maintenance is planned on a rotating electrical bus (F, G,
- H) and train (A, B) basis in order to minimize plant risk and ensure no impact on system safety function. DCPP evaluated the timing for replacement of the ASW Pump 2-2 motor to identify the week which provided the lowest risk for maintenance. Based on review of the DCPP Unit 2 planned maintenance schedule, the week of December 11 th 1
Enclosure PG&E Letter DCL-23-121 was identified as the earliest week for electrical Bus G work to support the ASW Pump 2-2 motor replacement while still maintaining low plant risk.
Impact on Plant Electrical Loads Each DCPP unit has two ASW pumps, and thus there are four total installed ASW
_ pumps for Units 1 and 2. DCPP has a total of five identical ASW pump motors, with one of the ASW pump motors serving as a spare. Motors are periodically replaced in either unit on a rotating basis in order to maintain high ASW system reliability. When a motor is removed, it is then inspected, refurbished (as needed), and tested, and becomes the new spare motor for placement at the next scheduled opportunity. Since each ASW pump (pump and motor) are identical, the replacement of the current ASW Pump 2-2 motor with the spare ASW pump motor beginning the week of December 11, 2023, will have no impact on the unit electrical load or electrical distribution systems.
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