Davis-Besse to undergo inspection after multiple diesel generator failures
Jul. 27—OAK HARBOR, Ohio — The Davis-Besse nuclear power plant will undergo a special inspection by the Nuclear Regulatory Commission after multiple diesel generator failures during testing and maintenance and a "complicated," unplanned automatic shutdown of a nuclear reactor on July 8, the agency announced Tuesday.
"The six-person inspection team will review the company's response to each diesel generator failure, including the company's cause analysis, extent of condition reviews, maintenance practices and system design," the NRC said in a prepared statement. "The team will also focus on the circumstances affecting the recent complicated automatic reactor shutdown, which was triggered by a turbine trip, assessing equipment performance and operator response."
Viktoria Mitlyng, senior public affairs officer at the agency's regional office in Lisle, Ill., said the inspection began Monday, has no "hard stop date," and doesn't even have a timeline because that will depend on what inspectors find.
"It will take as long as the inspectors need to review both issues and understand the circumstances of what happened and why," Ms. Mitlyng said.
The plant's two emergency diesel generators have failed four times during testing, and a station-blackout generator failed during maintenance, the statement said. Normal plant operations were not affected and public safety was maintained.
The emergency generators provide power to the plant if offsite power is lost, while the station-blackout generator is designed to back up those two. One diesel generator is sufficient for the plant to shut down safely and remain in a stable condition, the NRC statement said.
And while the NRC was planning its special inspection of the generator failures, Davis-Besse had an unplanned automatic shutdown of its nuclear reactor, and "certain pieces of equipment did not function as designed" during the ensuing response, the agency said.
"Operators took action to address the equipment issues, and the reactor was shut down safely and placed in a stable condition. After making the necessary repairs, the reactor returned to power," the statement said. "Based on the complications of the [unplanned automatic shutdown of a nuclear reactor], the agency chose to expand the special inspection to better understand equipment performance issues and operator response."
Davis-Besse, in Ottawa County's Carroll Township north of Oak Harbor, is operated by Energy Harbor Corp., an Akron-based former subsidiary of FirstEnergy Corp.
Energy Harbor representatives did not respond to requests for comment Tuesday afternoon.
First Published July 27, 2021, 2:01pm
