This telephone notification, as allowed by
10 CFR 50.73(a)(1), is being made pursuant to
10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of containment isolation valves in more than one system which occurred during the most recent refueling outage at Fermi 2. On 3/24/2017, at approximately 1548 EDT, when synchronizing an
emergency diesel generator (
EDG) to the grid during testing, an electrical perturbation occurred. Further investigation found that the
EDG was slightly out of phase when it was attempted to be synchronized to the grid. The electrical perturbation resulted in an unexpected half-scram of
Reactor Protection System (
RPS) A and actuation (closure) of some containment isolation valves. The actuations were invalid as they were not initiated in response to actual plant conditions or parameters satisfying the requirements for initiation. Fermi 2 was shut down for a refueling outage at the time, and therefore, the half-scram of
RPS A occurred after the safety function had already been completed. Containment isolation valves actuated (closed) in Division 1 of the Torus Water Management, Drywell Pneumatics, and Drywell Floor and Equipment Drain
Sumps systems. All valves operated as expected. Since containment isolation valves in more than one system were actuated by this perturbation, this event constitutes an event or condition that resulted in manual or automatic actuation of the system listed in paragraph
10 CFR 50.73 (a)(2)(iv)(B)(2) and is reportable under
10 CFR 50.73(a)(2)(iv)(A).
The NRC Resident Inspector has been informed of this notification.
