ENS 44718
ENS Event | |
|---|---|
20:20 Dec 13, 2008 | |
| Title | Steam Exclusion Boundary Door Latch Failure |
| Event Description | At 1420 on 12/13/08 a plant electrician identified that a steam exclusion door would not close when he was transiting through the door. This door would not have closed and maintained the Steam Exclusion Boundary and could have led to steam through out the Auxiliary Building which could have resulted in both Trains of ESF Equipment failing to perform their required functions, i.e., SI, RHR, CC etc. A Unit Supervisor who was in the Auxiliary Building at the time immediately went up to the door and found the latch was broke and the broken piece was removed which then enabled the door to close and latch. At 1425 on 12/13/08 the Steam Exclusion Boundary was restored to functional and both Trains of ESF Equipment restored to operable.
The licensee informed the NRC Resident Inspector.
01/22/2009 - Retraction of EN 44718, both trains of Engineered Safeguards Features (ESF) equipment inoperable due to a degraded steam exclusion boundary door. EN 44718 provided notification that both trains of ESF equipment (e.g. SI, RHR, CCW, etc.) were inoperable due to degradation of a steam exclusion boundary door in the auxiliary building on December 13, 2008. Subsequent engineering evaluation determined that the degraded door remained capable of fulfilling its steam exclusion function during the brief (five minute) period when it was degraded. A degraded latch mechanism prevented the door from latching closed. However, the door was closed against its door jam, which resulted in a sufficiently small gap such that total allowed leak path criteria were not exceeded. Additionally, the door swing was in the direction of postulated steam flow, such that the door would have been held in the closed position by any steam overpressure postulated under accident conditions. Therefore, the door remained functional and the supported ESF equipment in the auxiliary building remained operable. Consequently, this condition did not meet the reportabllity Criteria in 10 CFR 50.72. As a result, the notification made on 12/13/2008 (EN 44718) is hereby retracted. The licensee will notify the NRC Resident Inspector. Notified the R3DO (O'Brien). |
| Where | |
|---|---|
Kewaunee  Wisconsin (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-2.83 h-0.118 days <br />-0.0168 weeks <br />-0.00388 months <br />) | |
| Opened: | David Karst 17:30 Dec 13, 2008 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Jan 22, 2009 |
| 44718 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |