The Associated Press

CLEVELAND - A Nuclear Regulatory Commission official said there was no proof known to the commission last year of a serious technical problem with the reactor head at the Davis-Besse nuclear power plant.

Had proof been known, a shutdown might have been ordered sooner than actually happened, Brian Sheron, the agency's senior licensing and technical official, said Tuesday at the NRC's annual meeting in Washington on nuclear safety research.

With knowledge that boric acid was causing corrosion on the reactor head "we probably would have rethought whether we could approve anything beyond Dec. 31," Mr. Sheron said. Davis-Besse shut down for routine maintenance in February. But investigators in March found leaking boric acid had nearly eaten through the 6-inch steel cap on the reactor vessel. The plant in Oak Harbor, about 20 miles east of Toledo, has been closed since then as repairs are made.

Mr. Sheron made a presentation in support of the NRC's use of a new analytical process that focuses attention on nuclear plant areas having the most risk while eliminating unnecessary regulation.

In a separate interview, NRC Chairman Richard Meserve told The Plain Dealer he is "comfortable that in the aftermath of the Davis-Besse plant, there's been a very thorough examination of reactor vessel pressure heads. I am satisfied that the kind of corrosion that was found in there is not occurring anywhere else."

"We may not be so lucky as we were this time at Davis-Besse if the NRC continues with its `business-as-usual' swordsmanship," said Union of Concerned Scientists nuclear safety engineer David Lochbaum in prepared remarks for the meeting Wednesday. Mr. Lochbaum and other nuclear power industry critics maintain the decision to extend violated most if not all of the NRC's own safety guidelines for making risk-based decisions.