OAK HARBOR, Ohio — The Davis-Besse Nuclear Power Station remained shut down today as more details emerged about what caused the unplanned closure.
Workers identified a problem with electrical wiring that connects a terminal box to the motor that powers one of the plant’s four reactor coolant pumps, said Jennifer Young, a FirstEnergy spokesman.
The wiring requires repair, and testing of the motor continues, she said. She did not know when the plant would restart or what caused the wiring problem.
“That will be a longer investigation. That’s not an answer that I expect we will have quickly,” she said.
The plant automatically shut down about 9:20 p.m. Saturday. No injuries occurred, and there are no threats to public safety, Ms. Young said.
“We are still able to provide adequate cooling to the reactor,” she said.
Ms. Young said testing of the motor will be completed today, which will allow workers to determine what, if any, additional work is required.
She declined to estimate when the plant could be back in operation, saying the start time is “considered competitive information.”
“It could impact the price of power when any plant is down,” she said. “So that’s why in the competitive marketplace we can’t share estimated … return-to-service dates.”
Some residents reported hearing a loud noise Saturday night, a sound caused by nonradioactive steam leaving the vents during the shutdown process, Ms. Young said. The steam is created to turn the turbines to spin the generator.
She said customers will see no power interruption and said the incident was reported to the U.S. Nuclear Regulatory Commission.
NRC spokesman Viktoria Mitlyng, from the agency’s Chicago office, said an NRC resident inspector has been involved in monitoring the situation and will review the incident to try to determine a cause.
“Our residents [inspectors] were there to make sure that everything runs smoothly, and there were no complications. At this point, what we are doing is just monitoring the plant’s troubleshooting actions to figure out what happened,” she said. “The plant is in a stable condition.”
The plant has shut down because of problems before, including a roughly two-month closure in 2011. While it was shut down for maintenance and to replace a reactor head, hairline cracks were discovered in the concrete shield building. FirstEnergy blames the cracking on weather during the Blizzard of 1978.
The Ottawa County plant started in 1977. Its license expires in 2017, and operators are seeking a 20-year license renewal.
Contact Vanessa McCray at: email@example.com, or 419-724-6065, or on Twitter @vanmccray.