A self-revealing Green non-cited violation of
10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, was identified when the corrective action to prevent recurrence of a significant
condition adverse to quality did not preclude repetition of the event. Specifically, Exelon generated a corrective action to prevent recurrence during a root cause evaluation for a reactor
scram caused by spiking on
intermediate range monitor nuclear instruments that occurred in May 2004. In October 2013 another
scram caused by spiking on the intermediate range nuclear instrument occurred, which Exelon subsequently determined to be a repeat of the May 2004 event. Exelon entered this issue into their corrective action program as issue report 1567196. The inspectors determined that Exelons failure to preclude repetition of a significant
condition adverse to quality was a performance deficiency that was reasonably within Exelons ability to foresee and correct. This performance deficiency is more than minor because it is associated with the equipment performance attribute of the
Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The significance of this finding was determined using NRC
IMC 0609, appendix A, exhibit 1. This finding screened as very low safety significance (Green), because the finding did not contribute to both the likelihood of a
reactor trip and likelihood that mitigation equipment or functions would not be available. The finding does not have a cross cutting aspect as it is not reflective of current performance because the root cause and associated corrective actions to prevent reoccurrence were from 2004.