ENS 53288
ENS Event | |
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14:58 Mar 26, 2018 | |
Title | Temporary Loss of Control Room Envelope Boundary |
Event Description | At 1058 Eastern Daylight Time (EDT) on March 26, 2018, a Main Control Room (MCR) alarm was received for low control room positive pressure.
At 1100 EDT, a Control Room Envelope (CRE) door was found ajar and immediately closed. Technical Specification 3.7.10, Control Room Emergency Ventilation System (CREVS), was declared not met for both trains and Condition B entered. At 1100 EDT on March 26, 2018, the alarm cleared, CREVS was declared operable and LCO [Limiting Condition for Operation] 3.7.10, Condition B was exited. The safety function of the CRE boundary is to ensure the in-leakage of unfiltered air into the CRE will not exceed the in-leakage assumed in the licensing basis analysis of Design Basis Accident (DBA) consequences to CRE occupants. From 1058 EDT to 1100 EDT, WBN [Watts Bar Nuclear] was unable to validate that CREVS could fulfill its required Safety Function. This event is being reported pursuant to 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. |
Where | |
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Watts Bar Tennessee (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
Time - Person (Reporting Time:+-3.12 h-0.13 days <br />-0.0186 weeks <br />-0.00427 months <br />) | |
Opened: | Matthew Miller 11:51 Mar 26, 2018 |
NRC Officer: | David Aird |
Last Updated: | Mar 26, 2018 |
53288 - NRC Website | |
Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |