OAK HARBOR, Ohio -- Past several security gates and checkpoints, at the heart of the Davis-Besse nuclear power plant, crews are working 150 feet off the ground to apply a protective coating to the plant's concrete Shield Building.
Contractors who cut through the structure in October to create an access hole for replacing Davis-Besse's reactor head discovered a hairline crack inside the wall, and further study of the structure revealed more extensive cracking in the concrete.
As a result, FirstEnergy Nuclear Operating Co., which operates the plant, is applying a weatherproof coating to the building.
The coating work is expected to be completed by the end of September, Jennifer Young, a FirstEnergy spokesman, said on Thursday at a media event to showcase the project.
FirstEnergy engineers believe the 1978 blizzard caused the cracks when wind-whipped rain soaked into the concrete followed by a rapid, deep temperature drop that caused the moisture to freeze inside and expand. The phenomenon is not believed to have repeated itself since then, with the structure remaining stable for 33 1/2 years before the cracks' discovery last fall.
Other buildings at the plant were already coated as part of the plant's original construction.
The Shield Building contains the steel containment vessel that houses the nuclear reactor. It wasn't coated originally because "there was no requirement that it be done," said Jon Hook, design engineering manager for the company.
The coating now being applied is specially designed to repel water and keep it from permeating the concrete, he said. "We didn't just say, 'Give me a blue-light-special-type paint,' " he said.
The company said the building's structural integrity is not affected by the cracks but said the coating provides "another layer of safety."
That explanation doesn't satisfy Terry Lodge, a Toledo attorney representing a coalition of environmental groups that oppose an upcoming 20-year license extension for the facility.
The groups, including Beyond Nuclear, Citizens Environment Alliance of Southwestern Ontario, and Don't Waste Michigan, have urged regulators to deny the renewal for Davis-Besse when its license expires in 2017.
"I'm not at all comforted that they discovered an error that never should have happened to the most expensive and safety-significant building on the site," Mr. Lodge said Thursday.
Added Kevin Kamps of Beyond Nuclear, "It's 40 years too late. Weather sealant will not fix the cracks that are there."
First Published August 24, 2012, 4:51 a.m.
