ML20156A258
| ML20156A258 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/04/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1983-005-00 | |
| Download: ML20156A258 (1) | |
Text
LER 281/83-005 Event
Description:
Trip with AFW Pump Inoperable Date of Event:
February 11, 1983 Plant:
Surry 2 Summary Surry Unit 2 was operating at full power on February 11, 1983 when the turbine-driven auxiliary feedwater (AFW) pump tripped during testing. The turbine governor was found to be defective, causing the turbine to trip on over-speed. Corrosion in the regulator piston in the pump governor valve prevented the piston from moving freely, which led to a pump over-speed trip.
Since a trip was reported on February 8, 1983, this event was modeled as a trip with the turbine-driven AFW pump assumed to be inoperable. The conditional core damage probability estimated for this event is 3.8x10-6. The dominant sequence involves a transient with reactor trip success, failure of main and auxiliary feed water, and failure of feed-and-bleed cooling.