ML20149K383
| ML20149K383 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1983-005-00 | |
| Download: ML20149K383 (1) | |
Text
LER 247/83-005 Event
Description:
Transient with the Turbine-Driven AFW Pump Inoperable Date of Event:
March 8, 1983 Plant:
Indian Point 2 Summary During normal operation on March 8, 1983, while the 22 turbine-driven auxiliary feedwater (AFW) pump was being brought up to operating speed for a bimonthly surveillance test, the outboard bearing began smoking and the pump was removed from service for maintenance. Inspection of the pump indicated that repacking was required. A trip had occurred less than a month prior to this event on February 13 (Licensed Operating Reactors, Status Summary Report (NUREG-0020),
published monthly, U.S. Nuclear Regulatory Commission, hereafter referred to as NUREG-0020).
Assuming that a bimonthly test indicates that a test was performed every two months, half the surveillance period of the turbine-driven AFW pump is a month.
Since the trip occurred less than a month earlier, it was assumed that the problem with the AFW pump existed at the time of the trip. This event was modeled as a transient with the turbine-driven train of AFW failed. The model for the failure of AFW given an anticipated transient without scram (ATWS) requires the use of 2 of 3 pumps. The AFW/ATWS probability was set to 0.04 to reflect the probability of failure for motor-driven pump 22 or motor-driven pump 23. The conditional core damage probability of this event is 3.9x10-6. The dominant core damage sequence involves a successful reactor trip, the failure of AFW, the failure of main feed water, and failure of feed and bleed.