A self-revealing
NCV of
technical specification (TS) 5.4.1 was identified because the unit 2 B safety injection (
SI)
accumulator was made
inoperable when
FENOC operators did not follow procedural requirements to align
nitrogen to the
accumulator. Specifically, the operators did not align the
nitrogen header to the
accumulator prior to opening the valve to repressurize the
accumulator. The inspectors noted that this resulted in the
accumulator pressure falling below the TS pressure limit which required
FENOC to declare the
accumulator inoperable.
FENOCs corrective actions included immediately realigning the system, restoring
accumulator pressure and entering the issue into their corrective action program, CR 2014-09260. The performance deficiency is more than minor because it is associated with the configuration control attribute of the
mitigating systems cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability and capability of systems that respond to
initiating events to prevent undesirable consequences. Specifically,
FENOC did not have reasonable assurance that the
nitrogen pressure in the B
SI accumulator was sufficient to ensure injection into the core during an accident due to the misalignment of the
nitrogen header. This finding is of very low safety significance (Green) because the performance deficiency was not a design or qualification deficiency, did not involve an actual loss of safety function, did not represent actual loss of a safety function of a single train for greater than its technical specification allowed outage time, and did not screen as potentially risk-significant due to a seismic, flooding, or severe weather initiating event. This finding has a cross-cutting aspect in the area of Human Performance, Avoid Complacency, because
FENOC operators did not recognize the possibility of mistakes and did not implement appropriate error reduction tools while attempting to re-pressurize the B
SI accumulator. (H.12)