ENS 56480
ENS Event | |
|---|---|
21:30 Apr 18, 2023 | |
| Title | Safe Shutdown Capability and Accident Mitigation |
| Event Description | The following information was provided by the licensee via email:
Notification per 10 CFR 50.72 (b)(3)(v)(A) and (v)(D) At time 1630 CDT on 4/18/23, Comanche Peak Unit 1 entered TS (Technical Specification) 3.0.3 for 11 minutes due to declaring Train A component cooling water (CCW) inoperable in conjunction with a Train B centrifugal charging pump (CCP) inoperable for scheduled maintenance. This resulted in an event or condition that could have prevented fulfillment of a safety function, high head injection of the emergency core cooling system. CCP 1-02 and fan cooler were tagged out of service at 0400 CDT on 4/18/23 due to scheduled maintenance activities. Containment spray (CT) pump 1-03 seal oil cooler CCW leak was found by a watchstander at 0930 CDT on 4/18/23. Engineering determined that leakage was CCW from a pipe flange weld after insulation removal and could not [determine] operability and notified control room at 1630 CDT on 4/18/23. This placed unit 1 in a TS 3.0.3 condition from 1630 to 1641 CDT for approximately 11 minutes until CCP 1-02 was restored back to operable status. CCW was declared operable at 1912 after CT pump 1-03 seal oil cooler was isolated. CT pump 1-03 remained inoperable until weld repair completed. Train A CT pump 1-03 declared operable at 1211 CDT 4/19/23. ENS notification should have been made by 0030 CDT on 4/19/23. This report restores compliance. The NRC Resident Inspector has been notified.
The following information was provided by the licensee via phone and email: Although Comanche Peak Unit 1 conservatively entered a limiting condition for operation action statement and performed repairs immediately, further engineering inspection and evaluation concluded that the CCW system was fully able to provide the needed flow to the 1-03 CT pump seal coolers from the time of discovery (0930 CDT) until which time the piping was isolated for repairs. During this period, structural integrity of the joint was maintained, CCW inventory loss remained within acceptable limits, and CCW could perform its intended design and safety functions. Based on this revised operability determination, train A CCW was always operable, and TS 3.0.3 did not apply. Therefore, reportability requirements per 10 CFR 50.72 (b)(3)(v)(A) and (v)(D) did not apply, and a 60 day LER will not be submitted. The licensee notified the NRC Resident Inspector. Notified R4DO (Young) |
| Where | |
|---|---|
| Comanche Peak Texas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+39.98 h1.666 days <br />0.238 weeks <br />0.0548 months <br />) | |
| Opened: | Joe Ricks 13:29 Apr 20, 2023 |
| NRC Officer: | Adam Koziol |
| Last Updated: | Jun 7, 2023 |
| 56480 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |