TOLEDO, Ohio - Davis-Besse nuclear plant workers on Thursday were investigating what caused a pinhole-size leak found the previous evening spraying radioactive coolant, plant operators said.
Regulators and plant operators said the leaking coolant at the plant on Lake Erie near Toledo never got outside the building and posed no safety or health threat to the public.
It's not clear how much coolant spilled out because it drained into the plant's collection system that is designed to contain any leaks, said Jennifer Young, a spokeswoman for the plant operated by a subsidiary of FirstEnergy Corp.
Workers discovered the leak in a pipe weld Wednesday night as they were getting ready to restart the reactor after a monthlong maintenance shut down. The plant was at full pressure at the time but the reactor was not yet operating, Young said. It's not known exactly when the leak began, but it had been less than 24 hours, she said.
Such leaks are not uncommon, said Viktoria Mitlyng, a spokeswoman for the U.S. Nuclear Regulatory Commission. She said nuclear plants go through an extensive startup process after outages to look for problems. The leak Wednesday will be repaired, plant operators said.
Nuclear regulators are expected to decide next year whether to renew the plant's license. Several anti-nuclear groups have charged that the plant is unsafe and should not continue to operate.
The 35-year-old plant was shut down in the fall while its reactor head was replaced. At that time, crews found cracks in the outer concrete wall that's designed to protect the reactor. FirstEnergy said a lack of exterior weatherproof coating caused the concrete to crack and traced the cracks back to a 1978 blizzard when wind, rain and a drastic temperature drop caused moisture to penetrate the concrete.
Federal regulators allowed the plant to resume electricity generation in December after determining it could operate safely and didn't need repair.
The plant also was shut down from 2002 to 2004 because of an acid leak in a reactor head. Regulators fined Akron-based FirstEnergy $5.45 million and the company agreed to $28 million in civil penalties following what the Nuclear Regulatory Commission said was the most extensive corrosion ever found at a U.S. nuclear reactor.
At full power, Davis-Besse makes enough electricity for around 750,000 customers, primarily in Ohio.