The following information was provided by the licensee via phone and email:
This 60-day optional telephone notification is being made in lieu of a licensee event report (LER) submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B).
At approximately 1917 Eastern Standard Time (EST) on November 3, 2024, an invalid actuation of group 6 primary containment isolation valves (PCIVs) (i.e., containment atmospheric control/monitoring (CAC/CAM) and post accident sampling system (PASS) isolation valves) occurred. Reactor building ventilation isolated and standby gas treatment started, per design.
The group 6 isolation resulted from a spurious signal from the reactor building ventilation radiation monitor `A' channel. No manipulations associated with the isolation or reset logic were ongoing at the time, and no abnormalities were noted in the reactor building ventilation radiation values. The readings for both reactor building ventilation radiation monitor channels remained consistent with each other, with no readings approaching the isolation setpoint.
The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the system. Therefore, this event has been determined to be an invalid actuation.
During this event the
PCIVs functioned successfully, and the actuations were complete. This event did not result in any adverse impact to the health and safety of the public.