Entergy failed to restart its Pilgrim Nuclear Power Station on Tuesday, after bringing the reactor to 9 percent power before discovering an issue with the facility’s turbine turning gear, prompting the utility to shut the unit down.
The Massachusetts plant was first shut down Sept. 6 after a malfunction in which excessive water levels were recorded in the plant’s reactor vessel. The facility, which has experienced a number of unplanned shutdowns in recent years, was downgraded in 2015 to column 4 of the Nuclear Regulatory Commission’s Action Matrix, the lowest safety rating a plant can have while remaining in operation.
NRC spokesman Neil Sheehan said by email Wednesday that the NRC is not considering taking any further measures at the plant.
“The turbine is considered to be on the non-nuclear side of the plant. As such, this issue would not be expected to have an impact on our assessment of the plant’s safety performance,” Sheehan wrote.
The turbine turning gear slowly rotates the turbine and generator rotors during cool-down periods following shutdown, according to Sheehan. They warm during startup and when the unit is offline or on standby. Once the reactor is powered, the steam produced by the reactor provides the motive force required to turn the turbine and generator rotors. The turbine turning gear is disengaged when there is sufficient steam to provide the spinning force.
Sheehan said NRC is unaware of the exact nature of the turbine issue.
Entergy plans to close the Pilgrim plant in May 2019 for economic reasons.
