On December 27, 2007, an inspection port cover, about six inches wide and nine inches tall, associated with the B
ESW pump discharge strainer fell off following a system test. The B
ESW pump was started again and water discharged into the safety-related
ESW pump house.
ESW B was declared
inoperable. The licensee determined during initial inspections that the cover fastener was potentially loose and that the cover had last been worked on during the refueling outage in April 2007. The licensee completed their initial investigation, repaired the B
ESW strainer, and determined that no additional equipment damage had occurred due to the water discharge into the pump house. The licensee identified that a similar event occurred in year 1990 associated with the A
ESW strainer. The licensee noted that some corrective actions associated with the year 1990 event were not maintained. In particular, a corrective design change was not completed and corrective periodic maintenance was not continued. The inspectors remained concerned about whether appropriate maintenance had been performed on the strainer and continued to evaluate the issue at the end of the inspection period.
