ENS 46562
ENS Event | |
|---|---|
21:39 Jan 21, 2011 | |
| Title | Steam Exclusion Door Declared Inoperable |
| Event Description | On 1/21/2011 at 1539 CST, the NRC Resident Inspector informed the Control Room that the lower Cane bolt was disengaged on Steam Exclusion Door 3, between Emergency Diesel Generator Room B and the Cardox Room. While the Cane bolt was not engaged, the barrier was Non-Functional and, in accordance with TRM 3.0.9, all equipment supported by that steam exclusion barrier was immediately declared inoperable. This included both Emergency Diesel Generators A & 8, safety-related 4160 V Busses 5 & 6, Service Water Trains A & B, and safety-related 480 V Busses 51, 52, 61. & 62. In addition, with Service Water inoperable, the following equipment was also inoperable in accordance with TRM 3.3.1: Component Cooling Trains A & B, Safety Injection Trains A & B, Residual Heat Removal Trains A & B, Containment Spray and Cooling Trains A & B, Auxiliary Feedwater Pumps A & B, and the Turbine Driven Auxiliary Feedwater Pump. With all three AFW pumps inoperable. TS 3 A.b.2 was entered to immediately initiate action to restore one AFW Train to operable status and suspend all LCOs requiring mode changes until one AFW Train is restored to operable status.
Steam Exclusion Door 3 was properly secured at 1545 CST on 1/21/2011, and LCO 3.0.c and TS 3 A.b.2 were exited at that time. All equipment affected by the steam exclusion barrier is operable. This is reportable under 10 CFR 50.72 (b)(3)(v)(B), 'Any event or condition that at the time of discovery could have prevented the fulfillment of a safety function,' and under 10 CFR 50.72(b)(3)(ii)(B) 'any event or condition that results in the nuclear plant being in an unanalyzed condition that significantly degrades plant safety.' The licensee notified the NRC Resident Inspector.
Retraction of EN #46562 Non-Functional Steam Exclusion Door. On January 21, 2011, EN #46562 provided notification that both trains of ESF equipment (e.g., SI, RHR, ICS, etc ) were inoperable following discovery that the lower cane bolt was disengaged on steam exclusion Door 3, between emergency diesel generator Room B and an adjacent equipment room in the turbine building. With the lower cane bolt disengaged, the steam exclusion barrier was considered non-functional. A subsequent engineering evaluation determined that the Door 3 lower cane bolt was not required for Door 3 to fulfill its function as a steam exclusion barrier. The previously reported condition would not have resulted in an environment that would have adversely impacted the equipment protected by Door 3. Therefore, the door remained functional and the supported ESF equipment remained operable. Consequently, this condition did not meet the reportability criteria in 10CFR50.72. As a result, the notification made on January 21, 2011, in EN #46562 is hereby retracted. The NRC Senior Resident Inspector has been notified. Notified R3DO(Cameron). |
| Where | |
|---|---|
Kewaunee  Wisconsin (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+0.77 h0.0321 days <br />0.00458 weeks <br />0.00105 months <br />) | |
| Opened: | Mike Terry 22:25 Jan 21, 2011 |
| NRC Officer: | John Knoke |
| Last Updated: | Mar 22, 2011 |
| 46562 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |