American Electric Power (NYSE:AEP) reported April 9 that about 2,000 gallons of oil were released from a transformer that connects the two transmission switchyards outside Indiana Michigan Power’s (I&M) Cook nuclear plant.
The transformer failure at the Bridgman, Michigan facility occurred in the late afternoon on April 8.
The transformer holds 30,000 gallons of oil. The majority of the oil was contained by the spill berm, but approximately 2,000 gallons were released to the ground.
Cook Unit 1 is shut down and in a refueling outage. Unit 2 remained at 100% power. The transformer was energized at the time of the failure, but subsequent switching has it isolated. There is no impact to either Cook unit, the transmission grid or I&M customers.
The Cook fire brigade, I&M transmission personnel and local fire responders monitored the transformer overnight as clean up began. There were a few small fires that were quickly extinguished as the transformer drained and cooled. The cause of the transformer failure is not known.
The Nuclear Regulatory Commission (NRC), the State of Michigan Department of Environmental Quality and Berrien County Emergency Management were notified.
“We expect to recapture all the oil and fully restore the area,” said Cook Environmental Manager Jon Harner. “None of the oil reached storm drains or Lake Michigan.”
There was an oil leak from the Cook station in 2014 that did reach Lake Michigan.
The two Cook nuclear units are pressurized water reactors (PWRs) that both came online in the 1970s. Each has a nameplate generating capacity of more than 1,100 MW.
Indiana Michigan Power is a wholly owned subsidiary of AEP.