"Almost every plan for limiting carbon dioxide output includes keeping old nuclear plants running. But as those plants age, they turn up new problems.
The latest is at a plant owned by Progress Energy in Crystal River, Fla., where a gap was found inside the thick concrete of a containment dome.
The plant had been temporarily shut in late September so workers could replace the aging steam generators — which required them to cut a hole in the dome. (The steam generators at many aging nuclear reactors were intended to last the life of the plant, so no way for swapping them out was designed.)"
Matthew L. Wald reports for the New York Times November 23, 2009.