On October 31, 2004, at approximately 10:36 p.m.
CST, an automatic start of the Division 1
emergency diesel generator (
DG) occurred as a result of the loss of the Division 1 standby switchgear. The plant was in cold shutdown for a refueling outage at the time of the event. The normal feeder breaker to the Division 1 4160kv bus tripped during the Installation of test jumpers in preparation for surveillance testing. Due to inadequate use of error prevention practices, the technician inadvertently contacted an adjacent terminal, generating a trip signal to I the feeder breaker. The diesel generator started as designed on a bus low voltage condition, and its output breaker automatically closed, restoring power to the bus. At the time of the event, the reactor cavity was flooded to greater than 23 feet. The
reactor water cleanup system was in service and the Division 2
residual heat removal system was operating in the
shutdown cooling mode. These systems were unaffected by this event and continued to provide alternate means of coolant circulation. For the remainder of the surveillance test being performed, all work involving lifted
leads and jumpers was monitored directly by the test director. This event is 1being reported in accordance with 10CF1150.73(a)(2)(iv)(A) as an event that resulted in the automatic actuation of the Division 1
DG. This event was of minimal safety significance.