A finding of very-low safety significance (Green) and an associated
NCV of
Technical Specification 5.4.1.a, Procedures, was self-revealed on December 2, 2014 when procedural guidance failed to be implemented as written. Specifically, Procedure QCOA 6100-17, Revision 12, Loss of
SBO [Station Black-Out Normal 13.8kV Transformer
T42R-6 Feed to
4kV Bus 61 and 71, included inappropriate guidance to cross-tie Bus 61 and Bus 71. The licensees procedural guidance as written were technically infeasible and could not be implemented due to breaker interlocks caused by the digital control system interface that precluded the
4kV buses 61 and 71 from being cross-tied. The licensee entered this finding into their Corrective Action Program as
Issue Report 2487426 and
Issue Report 2706435 and removed the guidance to cross-tie the
4KV buses from the procedure. The performance deficiency was determined to be more-than-minor because it was associated with the Mitigating System cornerstone attribute of design control and adversely affected the cornerstone objective of ensuring the availability, reliability and capability of systems that respond to
initiating events to prevent undesirable consequences (i.e., core damage). The finding screened as of very-low safety significance (Green) because it did not result in the loss of operability or functionality of any structure, system, or component. Specifically, using other procedural guidance, operators were able to start both station black-out diesels within the hour. The inspectors did not assign a cross-cutting aspect associated with this finding because it was not confirmed to reflect current performance.
