On September 22, 2015, with James A. Fitzpatrick Nuclear Power Plant operating at 100 percent power, the Emergency and Plant Information Computer (
EPIC) indicated a spike in
Secondary Containment differential pressure during performance of a surveillance test associated with automatic initiation of the
Standby Gas Treatment System. Plant data systems recorded
Secondary Containment differential pressure exceeding the Technical Specification allowed value. The
Secondary Containment differential pressure was at or above zero inches of water for approximately ten (10) seconds, and then immediately trended negative following auto-start of one of the trains of Standby Gas Treatment. An operator was subsequently dispatched to the ventilation control panel, and verified that
Secondary Containment differential pressure was more negative than the Technical Specification allowed value.
This condition was entered into the Corrective Action Program, and subsequently, it was determined that the approximate ten second duration that Secondary Containment differential pressure was greater than the Technical Specification allowed value was reportable pursuant to 10 CFR 50.72(b)(3)(v)(C), as an event or condition that could have prevented fulfillment of a safety function. Secondary Containment was Operable following reestablishment of greater than or equal to 0.25 inches of water vacuum, and remains Operable.
The licensee has notified the NRC Resident Inspector.
