ENS 51584
ENS Event | |
|---|---|
02:07 Dec 4, 2015 | |
| Title | Excessive Control Room In-Leakage Identified |
| Event Description | On December 3, 2015 at 2107 [EST], the Control Room Emergency Ventilation System (CREVS) was declared inoperable due to a higher than allowed identified in-leakage rate for the Control Room Envelope (CRE) when in the Normal Operating Mode. Both Unit 1 & Unit 2 remain at 100 percent power and they share a common CRE.
At the time of discovery, there is a reasonable expectation this condition could prevent the fulfillment of the safety function of a system that is required to mitigate the consequences of an accident, thus satisfying the reporting criteria for 10CFR50.72(b)(3)(v)(D). Actions to implement mitigating actions were immediately initiated in accordance with Technical Specification 3.7.10. CREVS has been placed in Recirculation Ventilation Mode, isolating the control room from outside air. The NRC Senior Resident Inspector has been notified of the condition.
Following the 8-hour 10CFR50.72 notification made on 12/4/2015 (EN 51584) regarding the Control Room Emergency Ventilation System (CREVS) inoperability, an engineering evaluation determined inleakage did not exceed limits described in the Beaver Valley licensing basis. Therefore, the degraded Control Room Emergency Ventilation System remained Operable with the identified air inleakage as determined by the Control Room Envelope Habitability Program. As such, the safety function was never lost and the event notification is being retracted as it is not reportable pursuant to 10CFR50.72(b)(3)(v)(D). FENOC is planning to repair the degraded components of the system. The NRC Resident [Inspector] has been notified." Notified R1DO (Dimitriadis). |
| Where | |
|---|---|
| Beaver Valley Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-0.57 h-0.0238 days <br />-0.00339 weeks <br />-7.80786e-4 months <br />) | |
| Opened: | Samantha Baldwin 01:33 Dec 4, 2015 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Jan 7, 2016 |
| 51584 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |