River Bend Station experienced a reactor scram Monday resulting from an RPS actuation, according to an NRC release. Following the scram, reactor water level briefly lowered below level 3. The reactor is stable with pressure and temperature being controlled by the feed water system and main steam bypass valves, respectively. The cause of the scram was due to a turbine trip/low condenser vacuum. The low vacuum condition resulted from a loss of non-safety related 4160V switchgear that powers two of four circulating water pumps.
A suspected spurious Division II isolation of Reactor Core Isolation Cooling (RCIC) was observed, according to the report. Restoration of RCIC to standby is in progress. The plant is conducting causal investigations to fully understand the cause of the turbine trip. As information becomes available, River Bend Station will provide additional information.