ENS 51712
ENS Event | |
|---|---|
06:09 Feb 5, 2016 | |
| Title | Excessive Control Room In-Leakage Identified |
| Event Description | On February 5, 2015 at 0109 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. Unit 1 remains at 100 percent power and Unit 2 remains in Mode 3 for an unrelated planned maintenance outage. Unit 1 and Unit 2 share a common CRE.
This in-leakage was detected during additional testing following the event documented in EN #51584. 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 10 CFR 50.72 notification made on 02/05/2016 (EN 51712) regarding the Control Room Emergency Ventilation System (CREVS) inoperability, further engineering evaluation has determined the identified in-leakage does not result in exceeding the design criteria for dose to the control room personnel. Therefore the degraded Control Room Emergency Ventilation System remained operable with the identified air in-leakage 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 10 CFR 50.72(b)(3)(v)(D). The NRC Resident has been notified. Notified the R1DO (Jackson). |
| 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:+-2.33 h-0.0971 days <br />-0.0139 weeks <br />-0.00319 months <br />) | |
| Opened: | James Schwer 03:49 Feb 5, 2016 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Apr 4, 2016 |
| 51712 - 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 | Not Critical |
| Scram | No |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |