ENS 56944
ENS Event | |
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01:02 Jan 24, 2024 | |
Title | Accident Mitigation - Relief Valves Inoperable |
Event Description | The following information was provided by the licensee via email:
At 1640 CST on February 1, 2024, it was determined that a condition occurred that could have prevented the fulfillment of a safety function due to two of the four steam generator (SG) power-operated relief valves (PORVs) being simultaneously inoperable. In certain accident scenarios, more than two PORVs are needed to mitigate the consequences of an accident; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The first PORV was declared inoperable at 1025 on January 22, 2024, and the safety function is considered to have been lost when the second PORV was declared inoperable at 1902 on January 23, 2024. The safety function was restored at 2234 on January 23, 2024, when the first SG PORV was declared operable. There was no impact to unit 2. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The plant remained in mode 3 for the duration of the condition. The causes for the two PORVs being inoperable were neither related nor systemic in nature. All SG PORVs have been restored to operation. |
Where | |
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South Texas Texas (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
Time - Person (Reporting Time:+211.75 h8.823 days <br />1.26 weeks <br />0.29 months <br />) | |
Opened: | Matthew Dugger 20:47 Feb 1, 2024 |
NRC Officer: | Adam Koziol |
Last Updated: | Feb 1, 2024 |
56944 - NRC Website
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Unit 1 | |
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Reactor critical | Not Critical |
Scram | No |
Before | Hot Standby (0 %) |
After | Power Operation (100 %) |