Inspectors identified a Green non-cited violation (
NCV) of
Technical Specification (TS) 6.8.1 for failure to promptly implement actions to recover the Unit 1 skimmer surge tank (
SST) level during the 1R12 Unit 1 refueling outage. Prompt action by the operators would have prevented entrainment of the air into the
residual heat removal (
RHR) system, elevated radiation levels on the refuel floor, and subsequent entry into off-normal procedure ON-120, Fuel Handling Problems. Exelon entered this issue into their
CAP for resolution. This finding is more than minor because it affects the human performance attribute of the
Initiating Events cornerstone and the objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The inspectors evaluated this finding using
IMC 0609, Appendix G, Shutdown Operations
Significance Determination Process, Attachment 1. This finding is of very low safety significance (Green) because the finding did not require quantitative assessment per Checklist 7 of Attachment 1 to
IMC 0609 Appendix G. The reactor time-to-boil during this event was approximately
26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br /> and adequate time was available to vent and restart the affected
RHR pump in the Alternate
Decay Heat Removal (
ADHR) mode of operation. Additionally, during the time that
ADHR was secured, natural circulation provided reactor coolant flow. This finding has a human performance cross-cutting aspect in the area of work practices. Specifically, operators did not follow
OP-AA-103-102, Watchstanding Practices, in that they did not promptly implement actions required by the applicable alarm response procedure to recover
SST level following receipt of the associated control room alarm (
H.4(b))
