The inspectors identified a self-revealing
NCV of
Technical Specification (TS) 5.4.1, for two instances of failure to properly implement approved maintenance procedures and work order instructions. Specifically, maintenance electricians inadvertently removed the 2BD1CB safety related battery charger from service while attempting to perform a routine quarterly battery surveillance on the 2DD1CB battery charger. When the 2BD1CA/2BD1CB Trouble alarm was received in the control room, the operators immediately contacted the electricians and the work was halted. Battery charger 2BD1CB was restored to service within 31 minutes. In the second instance, maintenance electricians inadvertently rendered both battery chargers for the 1CD1 safety-related battery
inoperable during load-sharing adjustments on the 1CD1CB battery charger. The licensee restored the 1CD1CA battery charger to service within a few minutes. The licensee entered both of these issues into their corrective action program (CR 445343 & 457102 respectively). The inspectors concluded that this finding was more than minor because it impacted the Reactor Safety
Mitigating Systems Cornerstone objective to ensure the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences and affected the cornerstone attribute of equipment performance. Specifically, the unintentional opening of the
AC input breakers to the 2BD1CB, 1CD1CA and 1CD1CB battery chargers resulted in the chargers being declared
inoperable for several minutes. The inspectors used the Phase 1 Initial Screening and Characterization of Findings (
IMC 0609.04 Exhibit 1) to characterize the finding. Since the inspectors answered No to all of the Table 4a
Mitigating Systems Cornerstone questions, the inspectors concluded that the finding was of very low safety significance (Green). The inspectors determined that the cause of this finding was related to the Work Practices component of the Human Performance cross-cutting area due to less than adequate procedure use and self/peer checking.
