ENS 41877
ENS Event | |
|---|---|
02:25 Jul 28, 2005 | |
| Title | Two Trains of Control Room Emergency Ventilation Systems (Crevs) Inoperable and Not Restored within 24 Hours |
| Event Description | At 2125 on 7/27/05, Door 33021 (B Engineering Safety Feature Switchgear to B Emergency Diesel Generator) (B ESF Switchgear to B EDG) was found not to be latched. Reviewing history; the door was first discovered not to latch at 1215 on 7/26/05, by Security. The Control Room was notified at 2125 on 7/27/05 by an Equipment Operator, who found the door unlatched. Door was subsequently latched closed at 2155 on 7/27/05.
Due to this door not being able to be verified latched, T/S LCO 3.7.10.B should have been entered at 1215 on 7/26/05. This renders 2 trains of Control Room Emergency Ventilation Systems (CREVS) inoperable, and if not restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a plant shutdown is required; being in Mode 3 (Hot Standby) in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 (Cold Shutdown) in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The plant should have been in Mode 3 at 1815 on 7/27/05. This time was not met. As stated previously, the door was verified to be latched at 2155 on 7/27/05. A plant shutdown is not being made due to the LCO 3.7.10.B being satisfied at 2155 on 7/27/05. Door 33021 (B ESF Switchgear to B Emergency Diesel Generator) was repaired at 0022 on 7/28/05. This issue has been entered in the licensee corrective action program. The NRC Resident Inspector was notified of this event by the licensee.
Upon further review, it was concluded that this event is not reportable. The design functions of this door are pressure boundary and fire protection. Based upon the following criteria, this event was determined to be not reportable: 1) Pressure boundary: Actual duration of door inoperability did not result in a violation of Control Room Emergency Ventilation System Technical Specification Action completion time limits. 2) Fire protection: Only one fire suppression system was impacted and the inoperability of a fire protection suppression system for a single area is not reportable with regards to the Fire Protection Program. The loss of one fire suppression system was bounded by Callaway licensing basis. The licensee will notify the NRC Resident Inspector. Notified R4 DO (Powers) |
| Where | |
|---|---|
Callaway  Missouri (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:+3.53 h0.147 days <br />0.021 weeks <br />0.00484 months <br />) | |
| Opened: | Hope Bardley 05:57 Jul 28, 2005 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Sep 9, 2005 |
| 41877 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |