ML20147A344
| ML20147A344 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1983-008-00 | |
| Download: ML20147A344 (1) | |
Text
LER 334/83-008 Event
Description:
Transient with the Turbine-Driven Auxiliary Feedwater Pump Inoperable Date of Event:
February 18, 1983 Plant:
Beaver Valley 1 Summary On February 18, 1983 during routine surveillance testing of the turbine-driven auxiliary feedwater (AFW) pump, excessive pump heating at the inboard packing follower was observed. The pump was removed from service. Investigation revealed that the packing follower heatup was caused by a packing failure. Two outer rings were found dry. The pump was repacked and returned to service the next day. A plant trip occurred on February 12, 1983 due to low steam line pressure.
A fitting on the air supply line to the trip valve on the B main steam line TV-MS-101B had separated, allowing TV-MS-101 B to close (NUREG-0020).
Since the plant trip occurred only six days prior to the discovery of the failed AFW pump packing, this event was modeled as a transient with main feedwater (MFW) assumed unavailable and the turbine-driven AFW pump assumed failed. The MFW train was set to failed and the non-recovery probability was set to 0.1 to reflect the trip due to low steam line pressure, which would most likely isolate MFW. The third train of AFW was set to failed to reflect the inoperable turbine-driven pump.
The estimated conditional core damage probability for this event is 5.9x10-6. The dominant sequence involved the failure of AFW, the failure of MFW, and the failure of feed and bleed.