ML20149K474
| ML20149K474 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1982-021-00 | |
| Download: ML20149K474 (1) | |
Text
.
LER 338/82-021 Event
Description:
Transient with One AFW Pump Inoperable Date of Event:
April 16, 1982 Plant:
North Anna 1 Summary On April 16, 1982 following a manual reactor trip due to a loss of the circulating water pumps (NUREG- 0020), auxiliary feedwater (AFW) pump 3B was inoperable for a period of 78 minutes.
The control switch slipped when an attempt was made to place the switch in the pull-to-lock position. The pump momentarily re-energized while it was slowing down, which resulted in an overcurrent trip. AFW pump 3A was immediately lined up to supply steam generator B. The pump motor was bridged, meggered, and verified operable.
This event was modeled as transient with one AFW pump inoperable. The estimated conditional core damage probability is 1.8x10-6. The dominant sequence involved the failure of AFW, the failure of main feedwater, and the failure of feed and bleed.