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| Entered date | Event description | |
|---|---|---|
| ENS 56644 | 30 July 2023 17:25:00 | The following information was provided by the licensee via email: On July 30, 2023 at 1119 CDT, Waterford Steam Electric Station Unit 3 declared the control room envelope inoperable in accordance with technical specification (TS) 3.7.6.1 due to the control room envelope doors failing a door seal smoke test creating a breach in the control room envelope. Operations entered TS 3.7.6.1 Action b. Mitigating actions were implemented and tested satisfactorily by 1215 CDT. There was no impact on the health and safety of the public or plant personnel. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to mitigate the consequences of an accident, due to the control room envelope being inoperable. The NRC Resident Inspector has been notified.
The original operability determination of inoperable was made based on a conservative evaluation that with presence of smoke in-leakage through Door 261 and 262, the CRE boundary could not perform its safety function. A more detailed engineering evaluation was subsequently performed. No maintenance or intrusive testing was performed on the doors after initial test failure. As documented in version 2 operability determination for condition report WF3-2023-14604, the CRE boundary remained intact for the condition identified and was able to fulfill its safety function. The licensee has notified the NRC Resident Inspector. Notified R4DO (Warnick). |
| ENS 55963 | 25 June 2022 00:44:00 | The following information was provided by the licensee via email: At 2012 CDT, Waterford 3 Steam Electric Station, Unit 3 was operating at 100 percent power when an automatic reactor trip occurred due to Main Steam Isolation Valve MS-124B going closed unexpectedly. Subsequently, both main feedwater isolation valves shut. Emergency Feedwater (EFW) was automatically actuated. Preliminary evaluation indicates that all plant systems functioned normally after the reactor trip. The unit is currently stable in Mode 3. All control rods fully inserted as expected and all other plant equipment functioned as expected. This was an uncomplicated scram. This event is being reported as a 4-hour non-emergency notification in accordance with 10 CFR 50.72(b)(2)(iv)(B) as an actuation of the reactor protection system (RPS) when the reactor is critical and as an 8-hour non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as valid actuation of the EFW system. The NRC Resident Inspector has been notified. |