Green. The inspectors identified a finding of very low safety significance (Green) involving a non-cited violation (
NCV) of
10 CFR 50 Appendix B Criterion XVI, Corrective Action, because Exelon did not adequately identify and correct a
condition adverse to quality associated with the containment atmospheric dilution (
CAD) piping system. Specifically, in 2012, Exelon did not adequately identify the source of foreign material (FM) and implement corrective actions to remove the FM from the
CAD piping which resulted in the failure of the CHK-2-07C-40145 containment isolation valve to close in 2016. Exelon documented the issue in
issue report (IR) 2735344 and promptly replaced the valve and restored the valve to
operable. As an interim corrective action, Exelon plans to increase the local leak-rate test (
LLRT) frequency and replacement of the
check valve to maintain reasonable assurance of operability. Exelon is implementing a detailed troubleshooting plan to identify the source of FM and perform corrective actions to address the
condition adverse to quality. The performance deficiency (
PD) is more than minor because it was associated with the containment barrier performance attribute of the
barrier integrity cornerstone and it adversely impacted the cornerstone objective to provide reasonable assurance that physical design barriers (containment) protect the public from radionuclide releases caused by accidents or events. The inspectors evaluated the finding using
IMC 0609, Attachment 4, Initial Characterization of Findings, and Appendix A, The
SDP for Findings at-Power, Exhibit 3, and the inspectors determined this finding to be of very low safety significance (Green) because the degraded condition did not represent an actual open pathway in the physical integrity of containment, and did not involve an actual reduction in function of
hydrogen igniters in the reactor containment. The inspectors determined that a cross cutting aspect does not apply because the performance deficiency occurred greater than three years ago and is not indicative of current plant performance.
