Waterford – The Unit 2 reactor at Millstone Power Station shut down automatically around noon today, after some repair work had been made while the reactor was still online.

Earlier in the day, owner Dominion powered down the reactor from 100 percent to 30 percent without shutting it down completely to fix an oil leak in one of the motors that run the reactor coolant pumps, said company spokesman Ken Holt.

Operators made the repair, which involved removing a switch in the motor as a temporary modification, completed some extra maintenance work, he said, and then began powering back up. It was then that one of the pumps that supplies water to the steam generators automatically shut down, he said.

“Operators called for a manual shutdown at the same time that the reactor protection systems were initiating an automatic shutdown,” Holt said.

A review team is investigating the cause of the shutdown, he said.