A self-revealing
NCV of
TS 5.4.1.a, for failure to adequately implement procedures required by
Regulatory Guide 1.33, Appendix A, Section 9, Procedures for Performing Maintenance, was identified. Specifically,
foreign material exclusion control procedures as described in work orders were not implemented. This finding is more than minor because it affects the availability, reliability, and capability of one train of the RN system (
ultimate heat sink) and is related to the human performance and procedure quality attributes of the
mitigating systems cornerstone. This finding was considered self-revealing because the foreign material (i.e., divers knife) was discovered in the 2A RN strainer as a result of the loss of safety equipment functionality. Data related to the frequency of high RN strainer differential pressure alarms was reviewed by the NRC staff for the seasonal macro-fouling periods of 2006 and 2007 to determine the total actual exposure time that macro-fouling occurred. Based on the data, a collective period of less than 30 days was selected as a conservative, bounding exposure number to determine the significance of the collective seasonal macro-fouling for the period from 2006 until January 28, 2008. The issue is of very low safety significance based on review
IMC 0609 Appendix A pre-solved risk tables for loss of one train of nuclear
service water for less than 30 days. This finding has a cross-cutting aspect of decision making in the area of human performance
H.1.b] because the licensee failed to use conservative assumptions in decision making when deciding not to implement foreign material procedures. (Section 1R13
