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On September 17, 2001, Unit 1 was in Mode … On September 17, 2001, Unit 1 was in Mode 1 in coastdown operations in preparation for a refueling outage. A Train C Essential Cooling Water system outage was entered at 0200 hours in order to perform scheduled maintenance. On September 21, 2001, the Train C Essential Cooling Water pump was started in order to perform post-maintenance surveillance testing. The pump ran for approximately 10 minutes with what was thought to be adequate cooling and lubrication water flow. At approximately 2106 hours, the pump was manually stopped when output pressure dropped to zero. The pump was observed to come to an abrupt stop. Subsequent investigation identified that significant damage had occurred to the No. 2 pump bearing, and the lower pump shaft exhibited indications of overheating. The root cause of the pump damage was determined to be foreign material, which caused insufficient cooling/lubricating flow by obstructing the bearing flow orifices. Because pump repair time would exceed the 7-day Allowed Outage Time of Technical Specification 3.7.4, enforcement discretion was requested to permit continued operation of the unit while the pump was repaired. Enforcement discretion was granted on September 23 at 1800 hours. Repair work was completed and on September 26, 2001 at 0905 hours the Train C Essential Cooling Water system and the associated systems it supports were restored to operable status.</br></br>Corrective actions include revising operating procedures to contain additional pump stop criteria based on indicated lube water flow, and revising maintenance procedures to add specific foreign material exclusion/cleaning requirements prior to pump reassembly.</br></br>This event was reviewed for risk impact and found to be risk insignificant since the conditional core damage probability was approximately 8.24E-7.age probability was approximately 8.24E-7. +
September 24, 2001 +
On September 17, 2001, Unit 1 was in Mode … On September 17, 2001, Unit 1 was in Mode 1 in coastdown operations in preparation for a refueling outage. A Train C Essential Cooling Water system outage was entered at 0200 hours in order to perform scheduled maintenance. On September 21, 2001, the Train C Essential Cooling Water pump was started in order to perform post-maintenance surveillance testing. The pump ran for approximately 10 minutes with what was thought to be adequate cooling and lubrication water flow. At approximately 2106 hours, the pump was manually stopped when output pressure dropped to zero. The pump was observed to come to an abrupt stop. Subsequent investigation identified that significant damage had occurred to the No. 2 pump bearing, and the lower pump shaft exhibited indications of overheating. The root cause of the pump damage was determined to be foreign material, which caused insufficient cooling/lubricating flow by obstructing the bearing flow orifices. Because pump repair time would exceed the 7-day Allowed Outage Time of Technical Specification 3.7.4, enforcement discretion was requested to permit continued operation of the unit while the pump was repaired. Enforcement discretion was granted on September 23 at 1800 hours. Repair work was completed and on September 26, 2001 at 0905 hours the Train C Essential Cooling Water system and the associated systems it supports were restored to operable status.</br></br>Corrective actions include revising operating procedures to contain additional pump stop criteria based on indicated lube water flow, and revising maintenance procedures to add specific foreign material exclusion/cleaning requirements prior to pump reassembly.</br></br>This event was reviewed for risk impact and found to be risk insignificant since the conditional core damage probability was approximately 8.24E-7.age probability was approximately 8.24E-7. +
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04:13:58, 1 December 2017 +
November 19, 2001 +
September 24, 2001 +
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