A Green self-revealing finding was identified for the failure to implement effective and timely corrective actions to prevent failure of a main
feedwater regulating valve IFV000498 that resulted in a
reactor trip. This valve failed due to previously identified pneumatic positioner pilot valve malfunction caused by either pilot valve stem fretting and/or foreign material intrusion from various internal air supply sources. All three loop
feedwater regulating valve positioners and air supply components subject to potential sources of contamination were replaced prior to startup from the
reactor trip. During Refueling Outage 17, modifications were completed to reduce vibration induced wear of control air system components and improve air quality to the positioners until the current positioner models can be replaced with a new design. This finding was entered into the licensee=s corrective action program as Condition Report 08-00292. This finding is greater than minor because it is associated with the Initiating Event Cornerstone attribute of equipment performance, and adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during at-power operations. The finding was evaluated using Phase 1 of the At-Power
SDP, and was determined to be of very low safety significance (Green) because it did not contribute to both the likelihood of a
reactor trip and the likelihood that mitigating equipment or functions were not available. The cause of this finding was directly related to the aspect of appropriate and timely corrective action in the cross-cutting area of Problem Identification and Resolution (Corrective Action component) because actions to address previously identified
feedwater regulating valve positioner pilot valve fretting and foreign material intrusion were not implemented in a timely manner (
P.1.d). (Section 4OA2.3
