Nuclear Regulatory Commission Could Boost Oyster Creek Oversight After Faulty Valve Finding

The federal Nuclear Regulatory Commission has cited Exelon for using an incorrectly assembled electromagnetic relief valve to depressurize the reactor at the Oyster Creek Nuclear Generating Station on Route 9 in Lacey Township, an NRC spokesman said.

The inspection finding means that NRC oversight could increase above the normal level of oversight, said spokesman Neil Sheehan.

The valves are used to depressurize the reactor during a pipe break to allow coolant to be injected into the reactor core, he said.

"This is necessary to keep the nuclear fuel in the reactor covered and cooled as the shutdown progresses," Sheehan said. "It was identified during an NRC Problem Identification and Resolution inspection completed at the end of 2016."

Oyster Creek is currently in the normal level of oversight. But that could change if the fault valve is finalized, he said.

"Exelon will have an opportunity to request a regulatory conference to provide additional information to the NRC prior to our final decision, to submit a written response; or to accept the finding, in which case we will promptly finalize our decision," Sheehan said.

Exelon failed to follow EMRV reassembly instructions requiring that plant personnel reinstall previously removed lock washers on the cut-out switch lever for one of the plant’s EMRVs. This caused excessive friction between the solenoid frame and the cut-out switch level, which led to the valve not performing its safety function, he said.

Technical specifications require that all of the EMRV values must be operable when the plant is operating. But records show the incorrect reassembly of the valve led to it being inoperable between Sept. 5, 2014 and Sept. 19, 2016, Sheehan said.

In terms of immediate corrective actions, Exelon installed new cut-out switch lever plates with increased clearances, replaced the washers and verified correct assembly of the valves following the most recent refueling outage, he said.

Story: Patricia A. Miller

Image: Patricia A. Miller