OAK HARBOR, Ohio - Davis-Besse will slowly be taken down from full power starting tonight so it can be shut down for 21 days of inspections and maintenance beginning Monday, the longest outage since the nuclear plant was authorized for restart in March.
FirstEnergy Corp. agreed to perform the midcycle outage as a restart condition. Refueling, which occurs once every two years at the power plant, is to be done in 2006.
The plant had been idle more than two years after the Nuclear Regulatory Commission learned about unprecedented rust on Davis-Besse's old reactor head - by far the deepest corrosion ever at a U.S. nuclear plant and one of the industry's most dangerous scenarios since the partial meltdown at Three Mile Island, a Pennsylvania facility, in 1979.
The NRC accused FirstEnergy of trying to cut corners in order to save money by failing to do necessary maintenance. It cited safety-system design flaws and accused management of fostering a workplace atmosphere in which employees feared retaliation if they reported problems.
Those obstacles were addressed to the NRC's satisfaction prior to restart.
This follow-up outage has two goals: Making sure a 30-year-old replacement head from an unfinished plant in Midland, Mich., hasn't developed any leaks, and replacing any steam generator tubes that might be getting thinned out by normal wear, NRC spokesman Jan Strasma said.
An ultrasensitive moisture detector that FirstEnergy put
inside the reactor containment shell has not detected any signs of post-restart leakage, Mr. Strasma said. Davis-Besse was the first U.S. nuclear plant to have the French-designed moisture detector installed.
In addition to inspecting the reactor head, officials will inspect flanges on top of it that have leaked in the past. Officials also will inspect the bottom of the reactor, which was once suspected of leaking. No conclusive evidence of leakage ever was detected, but FirstEnergy officials have been unable to explain all of the rust stains on the bottom of the reactor.
The NRC will have its three resident inspectors, plus three additional inspectors, shadowing workers during the outage and performing their own inspections. The primary duties of the latter three will be to audit FirstEnergy's own inspection skills. A separate review of Davis-Besse's radiation protection program will be made to evaluate compliance with worker-safety requirements, Mr. Strasma said.
Steam generator tubes are normally inspected at least once every two years. Davis-Besse's steam generator was last inspected in 2002. The utility was allowed to put off that inspection until this year because the nuclear plant didn't operate for most of 2002 and all of 2003.
Richard Wilkins, a FirstEnergy spokesman, said no major issues are expected to turn up during the process. A pair of reactor coolant pumps that had been the focus of a whistleblower complaint will be inspected. There are no plans to refurbish that pair of pumps until 2006 unless problems are found, he said.
The plant has two pairs of those pumps. One pair was refurbished during the two-year outage.
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