On September 10, 2004 at
1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />, one steam supply isolation valve (TV-1MS-105B) to the steam-driven
Auxiliary Feedwater System Pump (FW-P-2) unexpectedly opened at Beaver Valley Power Station Unit No. 1, causing this pump to commence feeding all three
steam generators. FW-P-2 functioned as designed with steam being supplied to the pump's steam-drive turbine. Neither of the other two
Auxiliary Feedwater System motor-driven pumps were actuated at Beaver Valley Power Station Unit No. 1. This initially caused
Steam Generator Water Level Deviations alarms on all three
steam generators. The
steam generator levels returned to their normal operating levels via the automatic level control system. After determining that there was no demand for this
Auxiliary Feedwater System pump to be operating, the control room crew attempted to close TV-1MS-105B from the control room, without success. The upstream motor-operated isolation valve (MOV-1MS-105) to TV-1MS-105B was then closed to stop steam flow to FW-P-2, terminating the
auxiliary feedwater flow to the
steam generators.
No maintenance or tests were ongoing with the Auxiliary Feedwater System at the time. Subsequent investigation determined that this event occurred due to a failure of an instrument card within the Solid State Protection System which caused TV-1MS-105B to inappropriately open. Therefore this actuation was not initiated by a valid actuation signal.
This event is reportable pursuant to 10 CFR 50.73(a)(2)(iv)(A) since it involved an actuation of a PWR auxiliary feedwater water system train as per 10 CFR 50.73(a)(2)(iv)(B)(6). This pump start was not part of a pre-planned sequence and did not occur with this system properly removed from service.
However, pursuant to 10 CFR 50.73(a)(1), this event is being reported via this telephone notification instead of submitting a written Licensee Event Report since the automatic actuation of the Auxiliary Feedwater System pump was not generated by a valid actuation.
The licensee notified the NRC Resident Inspector.
