ENS 57252
ENS Event | |
|---|---|
06:46 Jun 7, 2024 | |
| Title | Control Room Envelope Failed Surveillance |
| Event Description | The following information was provided by the licensee via email:
At 0146 CDT on June 7, 2024, River Bend Station (RBS) was operating at 100 percent power when a loss of control room envelope (CRE) was declared due to failing to meet Technical Specification (TS) 3.7.2, Surveillance Requirement (SR) 3.7.2.4, during surveillance testing. Mitigating actions were established which included the ability to issue potassium iodide to control room staff. With mitigating actions in place, the dose consequence to control room staff continued to be less than the regulatory limit of 5 rem total effective dose equivalent for the duration of a design basis event. The CRE is considered a single train system at RBS, therefore, this event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. 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 failed surveillance (SR 3.7.2.4) was for unfiltered air in-leakage greater than 300 cubic feet per minute.
This event was initially reported under 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. The licensee determined in a subsequent engineering evaluation of the conditions that existed at the time, that there was no adverse impact on the control room emergency ventilation system or the control room envelope (CRE) boundary's ability to perform its safety function. The CRE would not have been challenged to meet the regulatory limit of 5 rem total effective dose equivalent for the duration of a design basis event. Consequently, this condition is not reportable as an event or condition that could have prevented the fulfillment of a safety function. The NRC resident inspector has been notified. Notified R4DO (Vossmar). |
| Where | |
|---|---|
River Bend  Louisiana (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:+1280.4 h53.35 days <br />7.621 weeks <br />1.754 months <br />) | |
| Opened: | Terry Blanchard 15:10 Jul 30, 2024 |
| NRC Officer: | Adam Koziol |
| Last Updated: | Aug 5, 2024 |
| 57252 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |