The owner of an Ohio nuclear plant along Lake Erie says a lack of exterior weatherproofing coating caused concrete to crack in the outer shell protecting the plant.
FirstEnergy Corporation told the Nuclear Regulatory Commission that the exterior cracking at the Davis-Besse plant near Toledo traces back to a 1978 blizzard when wind, rain and a drastic temperature drop caused moisture to penetrate the concrete. The Blade newspaper reports the utility says the moisture caused the concrete to freeze and expand, prompting the cracks found in October.
FirstEnergy is proposing it could apply a weatherproofing coating and make sure the cracks haven't spread. It also proposes a long-term monitoring plan.
The NRC allowed the plant to begin producing electricity again in December after the first cracks were found.