The FirstEnergy (NYSE:FE) Perry nuclear facility in Ohio went offline unexpectedly on the afternoon of Feb. 8, according to an event report filed with the Nuclear Regulatory Commission (NRC).
“At 1500 EST on February 8, 2016, two safety relief valves (SRV) opened upon a spurious Division 2 initiation signal,” according to the report. “This caused suppression pool temperature to increase. At 1503 EST, plant operators took action to manually SCRAM the reactor at 95 degrees Fahrenheit in the suppression pool per plant procedures. The SRVs closed immediately following the scram at 1503 EST. The cause of the SRVs opening is currently under investigation.”
The plant was listed at zero generation by NRC early Feb. 9. The plant had also experienced an unplanned outage during a wintry weekend in late January.
Company officials had recently reported that Perry ran very reliably in 2015. FirstEnergy’s Perry nuclear plant achieved industry-leading reliability for the year, operating with a forced loss rate of zero.
“Perry remains offline while the team investigates what caused the valves to open and determines any actions necessary to correct the issue,” a FirstEnergy spokesperson said in an email. “Investigation so far has revealed that one of four instruments that measure pressure in the reactor sent an invalid signal for the valves to open even though plant conditions did not require them to do so,” the spokesperson said.
“Plant personnel do not believe the shutdown is related to Perry’s recent outage to repair a weld on a plant water system; however, the investigation will look closely at that along with all other potential causes. Restart is expected late in the week,” the FirstEnergy representative added.
Perry is a single-unit boiling water reactor (BWR) located in Lake County, Ohio. It has a summer capacity rating of more than 1,200 MW, according to GenerationHub data.