On April 4, 2006, at approximately 2:46 p.m., the Division 2 standby
service water system started automatically in response to a low pressure condition in the normal
service water system. The plant was operating at 98 percent power at the time of the event. A planned shift of the running normal
service water pumps was being performed, and system pressure momentarily dropped below the trip setpoint of the instrumentation that starts the standby
service water pumps. This condition is being reported in accordance with
10CFR50.73(a)(2)(iv)(A) as an automatic actuation of the standby
service water system. Operators implemented the appropriate response procedures, and the Division 2
SSW system was restored to its normal alignment at 5:36 p.m. that day.
The standby
service water system responded as designed to the low pressure condition in the normal
service water system. This event was of minimal safety significance.