A self-revealing
NCV of
TS 4.5.2b was identified for failure to properly fill and vent a portion of decay heat/low pressure injection train 1 after maintenance which resulted in an approximate 15 cubic foot air void in the discharge piping of the train 1 decay heat/low pressure injection system for approximately 59 days of plant operation. Work packages and procedures used in restoration and refilling of the system did not adequately identify and provide for filling of drained high points in the piping. Upon identification with a 6 inch step decrease in pressurizer level while aligning the decay heat system for refueling operations, the licensee filled and then vented the system from high point vents located in systems discharge piping in the plants containment. The licensee entered the failure to properly fill and vent the system after maintenance in their corrective action program. The finding is greater than minor because it was associated with the equipment performance attribute of the
Mitigating Systems cornerstone, and affected the cornerstone objective in that permitting an air void in the trains discharge piping affected the reliability and capability of the system. The finding is of very low safety significance because it did not result in a loss of function per Part 9900, Technical Guidance
Operability Determinations and
Functionality Assessments, did not represent an actual loss of safety function, and is not potentially risk significant due to external events. The finding is associated with the cross-cutting area of human performance in that the resources and specifically work packages and procedures were not adequate to ensure that the train 1 decay heat/low pressure injection system was restored to a filled and vented system condition (
H.2(c)) after completion of maintenance activities. (Section 4OA2
