A spokesman for the Nuclear Regulatory Commission said the plant’s control room operators manually shut down the reactor on Saturday in response to increasing reactor pressure.
"Cooldown was achieved using the plant’s isolation condensers," said Neil Sheehan, NRC spokesman.
At the time of the shutdown, turbine valve testing was being performed on the plant; the cause of the problem involving the turbine control system has not yet been determined, Sheehan said.
According to Sheehan, one of the NRC resident inspectors assigned to Oyster Creek on a full-time
basis responded to the site following the shutdown to independently
verify that the plant was in a safe condition and that the operators
were taking the appropriate actions.
"The inspector did not identify any significant concerns with the [shutdown] or with subsequent operator actions to stabilize the plant," said Sheehan.
Suzanne D'Ambrosio, plant spokeswoman, said staff will take advantage of the outage to perform additional maintenance work to "keep the unit operating reliably and efficiently."
There has not yet been a determination as to when the plant will return to service.