ENS 43059
ENS Event | |
|---|---|
07:05 Dec 21, 2006 | |
| Title | Accident Mitigation - Auxiliary Feedwater System |
| Event Description | A condition was identified [at 0205 on 12/21/06] involving improper placement of temporary scaffolding that could have resulted in all three Auxiliary Feedwater (AFW) pumps becoming inoperable during a high energy line break (HELB) in the Turbine-Driven Auxiliary Feedwater (TDAFW) pump room.
Scaffolding, erected to perform maintenance on the floor above the TDAFW pump room, had two vertical members placed on the high energy line break blowout panel in the TDAFW pump room roof that could potentially have restricted the ability of the panel to lift during a HELB event in the TDAFW pump room. Failure of the panel to lift during the event may cause the structural limit of the walls separating the TDAFW pump room from the motor driven AFW pump room to be exceeded. This could have resulted in all three AFW pumps becoming inoperable. At 0530 on 12/21/06, scaffolding removal was complete and AFW operability was restored. This condition is being conservatively reported, pending further evaluation, per 10CFR50.72(b)(3)(v) as a condition that at the time of discovery could have prevented the fulfillment of a safety function. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
| Millstone Connecticut (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+2.32 h0.0967 days <br />0.0138 weeks <br />0.00318 months <br />) | |
| Opened: | Fred Nygard 09:24 Dec 21, 2006 |
| NRC Officer: | Bill Gott |
| Last Updated: | Dec 21, 2006 |
| 43059 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |