The Oyster Creek Nuclear Power Plant in Lacey Township is offline while inspections are being performed, according to a press release. 

Oyster Creek nuclear plant (Excelon)

Operators began shutting the facility down at 8 p.m. Monday to inspect and replace a piece of safety equipment that operates valves inside the drywell. The inspection can't be performed while the reactor is in operation, plant officials said.

Nuclear Regulator Commission Spokesman Neil Sheehan said the work is in response to degradation of five electromatic relief valves (ERVs).

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.

NRC inspectors are monitoring the developments and will continue to do so until the problem is satisfactorily resolved, according to Sheehan.

Officials have not said when the plant will be brought back on-line.