The U.S. Nuclear Regulatory Commission seeks to fine FirstEnergy Corp. $5.45 million for not catching an unprecedented problem at its Davis-Besse nuclear plant in Ohio, and for giving the agency bad information regarding the problem component, according to MarketWatch.

If made official, the fine would be the largest ever in agency history, assessed for one of the worst U.S. nuclear incidents. The fine would more than double the NRC's prior record, according to MarketWatch.

"This substantial fine emphasizes the very high safety and regulatory significance of FirstEnergy's failure to comply with NRC requirements and the company's willful failure to provide the NRC with complete and accurate information," said Luis Reyes, the NRC's executive director of operations, in a release.

FirstEnergy discovered in early 2002 that leaking boric acid had nearly eaten through Davis-Besse's heavy reactor lid, forcing the northern Ohio plant into a two-year, $600 million repair outage.

The NRC contended FirstEnergy deserves a $5 million fine for restarting the plant from an outage in May 2000 without a required cleanup and inspection of the vessel lid. And the company deserves an added $450,000 fine for providing bad information that year regarding the cleaning and inspection, the agency said.

Specifically, the NRC singled out a former Davis-Besse system engineer for improper actions during the 2000 outage. He "deliberately provided incomplete and inaccurate information in plant documents, which are required by the NRC," the agency said in the release.

The NRC barred the engineer from taking part in any NRC-regulated activities for five years, and said others could be targeted soon.

A FirstEnergy spokesman confirmed that the engineer was fired and later sued the company over the matter, shortly after the corrosion problem emerged. The spokesman noted that FirstEnergy has long conceded that it provided the NRC inaccurate information about Davis-Besse's vessel lid maintenance.

In a statement, FirstEnergy said it is reviewing the violation notice, and said an NRC letter to the company said no further civil action is expected, aside from an ongoing U.S. Department of Justice probe. The NRC previously referred the Davis-Besse matter to the Justice Department.

Both FirstEnergy and the dismissed engineer have 90 days to respond to the enforcement action, and they can request additional time. Once that period is over, plus any requested appeals or hearings, the fines may become official, an NRC spokesman said.

Davis-Besse restarted in early 2004 following a major overhaul, including the installation of a new reactor lid, and according to NRC and FirstEnergy has run well since then. FirstEnergy also shook up its nuclear subsidiary and instituted a host of new practices in efforts to address what the NRC called "safety culture" problems, reports MarketWatch.