| 08-23-2005 | On June 24, 2005, at approximately 1:13 a.m. CDT, an unplanned automatic start of a Division 2 standby service water pump occurred. The plant was in cold shutdown at the time. This event is being reported in accordance with 10CFR5073(a)(2)(iv) as a condition that resulted in the automatic initiation of an emergency service water system. The Division 2 subsystem was being aligned to support diagnostic testing of a motor-operated valve in the system. The other Division 2 pump had already been started in accordance with the system operating procedure, and the subsequent steps directed the operator to open the inlet valve to the standby cooling tower. At this point, the pressure in the normal service water supply header decreased momentarily below the trip setpoint of the Division 2 automatic start circuitry. The second Division 2 pump started as designed. The causal analysis determined that the system operating procedure was inadequate for the alignment being performed, as it did not preserve sufficient margin in the normal service water supply pressure to avoid actuation of the low pressure trip units that start the standby system.
The system operating procedure has been changed to correct this deficiency. No loads being supplied by service water were adversely affected by the actuation of the second Division 2 standby service water pump. Thus, this event was of minimal safety significance. |
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| Docket Numbersequential Revmonth Day Year Year Month Day Yearnumber No. 05000 | |
| Event date: | 06-24-2005 |
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| Report date: | 08-23-2005 |
| 4582005002R00 - NRC Website | |