The corrosion in the lid of the Davis-Besse reactor was the most extensive ever at a U.S. nuclear reactor and led to a nationwide review of 69 similar plants.

The NRC bases the amount of fines on the severity of the violations, the company's record, how the plant identified the problems and whether it corrected them quickly.

The agency expects to make a final determination of Davis-Besse's liability this fall after further review by senior agency officials.

The company expects to be fined, FirstEnergy spokesman Todd Schneider said Monday.

Any fine would be in addition to the estimated $200 million or more that Akron-based FirstEnergy is paying to repair the crippled plant, install a new lid and buy replacement power until it is restarted.

Large fines the NRC has recently levied include $2.1 million against the operators of the Millstone nuclear plant in Connecti-

cut in 1997 and $500,000 against D.C. Cook in Michigan in 1998.

Davis-Besse's reactor has been idle since Feb. 16 and will probably not get NRC approval to restart before the end of the year.

In the wake of Davis-Besse's corrosion, along with unexpectedly severe cracking found in nozzles in the reactor lids at several other plants that operate at high pressure, the NRC is warning that current "eyeball" inspections of the lids may not be adequate.

The NRC issued a bulletin Friday suggesting several ways instruments can be used to detect cracking of the nozzles in the 6 1/2-inch-thick steel lids. The nozzles allow control rods to move in and out of the reactor core.

It recommends how often such inspections should be done but stops short of ordering them. Operators that don't intend to perform the advanced inspections are asked to explain their reasons. All reactor operators must respond by Sept. 9.

Giving operators an option on whether to do the inspections lets the industry determine how it will be regulated, say critics David Lochbaum of the Union of Concerned Scientists and Paul Gunter of the Nuclear Information and Resource Service. Both groups are closely following the Davis-Besse situation.

"It's this kind of ambiguity that doesn't foster confidence on the part of the public," said Gunter. "It's like being in the passenger seat with the driver not fully in control. The industry is driving the agency."