The following information is provided as 60 day telephone notification to the NRC in accordance with
10 CFR 50.73(a)(1) reported under
10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of Division 1 Shutdown
Service Water (
SX) and an invalid actuation signal for Division 1 Containment Isolation Group 12. This event occurred on July 26, 2014, at 1648
CDT. As allowed by
10 CFR 50.73(a)(1) this notification is made via telephone.
(a) The specific train(s) and system(s) that actuated were:
On July 26th, during lightning strikes on the switchyard grid system, the Division 1 SX (Shutdown Service Water) auto-started as a result of momentary loss of power to the Low Pressure Auto Start Relay. A lightning strike causing voltage transients also caused a Division 1 Group 12 Containment Isolation signal affecting DIV 1 Hydrogen monitor.
(b) Whether each train actuation was complete or partial.
Upon receiving the invalid signal from momentary loss of power, for Division 1 SX and Group 12 Containment Isolation signal, the systems responded as expected for existing plant conditions. For group 12 isolation, [Containment Monitoring] 1CM011/12/47 and 48 valves closed from their normally open position. For DIV 1 Shutdown Service Water (SX), the start of the Shutdown Service Water (SX) pump and alignment of valves operated as expected. The actuation was considered a complete Division 1 SX and Division 1 Group 12 Containment Isolation actuation.
Containment Isolation Signals:
The following Group 12 valves closed and associated shunt trips occurred on a loss of power to [Radiation Monitors] 1RIX-PR001A/1C: 1CM011, 1CM012, 1CM047, and 1CM048.
(c) Whether or not the system started and functioned successfully.
Upon receiving the invalid signal from momentary loss of power, Division 1 SX and Containment Isolation signals started and functioned successfully.
The NRC Senior Resident Inspector has been notified.
