Operators at the Oyster Creek Generating Station began a plant shutdown at 8 p.m. Monday night to inspect and replace a piece of safety equipment that operates valves located inside the drywell, Exelon spokeperson Suzanne D'Ambrosio said.
"Because the equipment is inside the drywell, this inspection cannot be performed while the reactor is in operation," she said.
The Oyster Creek nuclear power plant was shut down last night in response to degradation of electromatic relief valves (ERVs) that has been identified. Five such valves are involved.
Oyster Creek staff had planned to visually inspect the valves and
replace components as necessary while the plant was shut down, D'Ambrosio said.
The ERVs are part of the plant's automatic depressurization system (ADS), which supports the emergency core cooling system. The ADS is designed to depressurize the reactor during a small (pipe) break loss-of-coolant accident to permit the low-pressure core spray system to inject water into the reactor core, according to the facility.
Inspectors assigned to Oyster Creek on a full-time basis have been closely following developments involving the evaluation of the valves and the decision to take the reactor off-line to address the issue. They will continue to do so until the problem is satisfactorily resolved, according to the facility.
Here is a link to the Event Notification Exelon submitted to us regarding the outage: http://www.nrc.gov/reading-rm/doc-collections/event-status/event/en.html .