The operator of an Ohio nuclear plant along Lake Erie has found more cracks in the concrete building housing the reactor.
FirstEnergy Nuclear Operating Corp. says concrete sampling also showed that three cracks first detected in the shield building of the Davis-Besse plant near Toledo in 2011 have grown a bit. But the company and the Nuclear Regulatory Commission said Friday that the findings don't mean the structure is unsafe.
The company says high-definition cameras now used for inspecting core samples identified the previously unseen cracks.
Hairline cracks were found in the 2.5-foot thick concrete in 2011. FirstEnergy determined they were caused by wind-blown moisture seeping into the concrete and freezing.
FirstEnergy has since weatherproofed the building.