ENS 52808
ENS Event | |
|---|---|
16:19 Jun 15, 2017 | |
| Title | Temporary Loss of Shield Building |
| Event Description | At 1219 [EDT] on June 15, 2017, annulus vacuum exceeded its pressure limit. At that time, the Shield Building was declared inoperable in accordance with Technical Specification 3.6.15 Condition A and B, due to the inoperability of the Shield Building (CRE). At 1222 [EDT], annulus pressure returned to normal, Shield Building was declared operable and LCO 3.6.15, Condition A and B were exited.
The temporary loss of the Shield Building resulted from a loss of pressure control in the Auxiliary Building caused by a loss of Auxiliary Building General Ventilation. The Auxiliary Building Gas Treatment System was started to maintain Auxiliary Building pressure within limits and the non-safety related Annulus Vacuum system automatically restored annulus pressure. The Shield Building ensures that the release of radioactive material from the containment atmosphere is restricted to those leakage paths and associated leakage rates assumed in the accident analysis during a LOCA. The EGTS system [Emergency Gas Treatment System] would have automatically started and performed it's design function to maintain Annulus Vacuum within required values. This event is being reported pursuant to 10 CFR 50.72(b)(3)(v)(D). NRC Resident Inspector has been notified. |
| Where | |
|---|---|
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:+2.07 h0.0863 days <br />0.0123 weeks <br />0.00284 months <br />) | |
| Opened: | Tim Taylor 18:23 Jun 15, 2017 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Jun 15, 2017 |
| 52808 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |