The inspectors identified a Green
NCV of
TS 3.11.2.5, Explosive Gas Mixture, for the failure to implement the actions of the limiting condition for operation (LCO). Specifically, during shutdown plant operations in November 2013, the licensee identified
oxygen concentrations in the gaseous radwaste treatment system (
GRTS) of greater than two percent
oxygen, with
hydrogen concentration greater than four percent and did not enter nor take the actions of TS
LCO 3.11.2.5. The licensee entered the issue into their
CAP as
AR #651188 and reduced the
oxygen concentration to less than two percent on December 11, 2013. The licensees failure to enter and implement the actions of TS
LCO 3.11.2.5, once
oxygen concentrations exceeded two percent, with
hydrogen concentrations greater than four percent within the
GRTS was a performance deficiency. The performance deficiency was determined to be more than minor in accordance with
IMC 0612, Appendix B, because if left uncorrected, it would have the potential to
lead to a more significant safety concern such as an explosive gas mixture. Specifically, on November 11, 2013,
SR 4.11.2.5 was performed unsatisfactorily; Operations was unaware of the results and did not implement the actions of TS LCO 11.2.5. Using
IMC 0609,
SDP, Appendix A, Exhibit 2-External Event Mitigation Systems Screening Questions, the inspectors determined this finding to be of very low safety significance (Green) because it was a deficiency that did not result in a degradation or loss of system function. The finding had a cross-cutting aspect of Procedure Adherence, as described in the Human Performance cross-cutting area because the licensee failed to comply with RST-202,
Hydrogen and
Oxygen Surveillance of the
GRTS, and notify Operations of the unsatisfactory test result.