Exelon (NYSE:EXC) took its 636-MW (net) Oyster Creek nuclear plant in New Jersey offline July 7 to replace a piece of safety equipment.
Exelon said in a statement that it commenced a plant shutdown at 8 p.m. to support inspections and replacement of a piece of safety equipment that operates valves located inside the drywell.
Because the equipment is inside the drywell, this inspection cannot be performed while the reactor is in operation. Staff planned to visually inspect the valves and replace components as necessary while the plant is shut down.
As of early Tuesday, July 8, Exelon was still continuing the slow deliberate process of reducing power for the shutdown and repair. The Nuclear Regulatory Commission (NRC) daily reactor report listed the facility at 30% generation on July 8.
“On July 7, 2014 at approximately [2040 EDT], an issue was discovered with currently removed Electromatic Relief Valves (EMRVs) that calls the operability of the currently installed EMRVs into question,” according to an NRC event notification report on the situation at Oyster Creek.
“Based on this new information, all 5 of the currently installed EMRVs were conservatively declared inoperable. With the potential of 5 EMRVs inoperable a Technical Specification shutdown is required under Technical Specification 3.4.b, whereby reactor pressure shall be reduced to 110 psig or less within 24 hours,” the NRC event report went on to say.
Oyster Creek is a single-unit boiling water reactor (BWR) that was commissioned in 1969. The plant is located about 60 miles east of Philadelphia in Ocean County, N.J.
Although the plant is federally licensed to operate until 2029, Exelon plans to retire the facility in 2019.
Oyster Creek underwent a planned maintenance outage last fall. Meanwhile another nuclear unit in New Jersey, Public Service Enterprise Group (NYSE:PEG) Salem 1, currently remains offline due to a planned refueling and maintenance outage.