This 60-day telephone notification is being made in accordance with the reporting requirements specified by
10 CFR 50.73(a)(2)(iv)(A) and
10 CFR 50.73(a)(1) to describe an
invalid actuation of a general containment isolation signal affecting multiple
Main Steam Isolation Valves (
MSIVs).
On April 2, 2017 at approximately 2127 Eastern Daylight Time, during performance of a reactor vessel leak check, all four inboard MSIVs closed as a result of actuation of the Main Steam Line (MSL) high flow instrumentation. The high flow signal was spurious on two channels with no flow in the MSLs. Since an actual high flow condition did not exist at the time of the actuation, the actuation was considered invalid. The MSIVs functioned as designed on actuation of the MSL high flow instrumentation. All outboard MSIVs were closed at the time of the actuation.
The NRC Resident Inspector has been notified.