07/03/02

Washington

- In 1990, the Nuclear Regulatory Commission signed off on Davis-Besse's plan to prevent corrosion on its nuclear reactor, despite concerns that the program had significant problems.

The agency's "acceptable" grade for Davis-Besse signaled the end of the NRC's special attention to corrosion-prevention work at the plant.

During the next 12 years, the plant would repeatedly ignore basic corrosion-monitoring duties as well as warnings from a corrosion study that the plant's owner commissioned. Davis-Besse managers at one point allowed so much corrosion to build up on the reactor lid that workers needed crowbars to remove it.

A review of NRC and FirstEnergy Corp. records over the decade shows the agency assumed the company was doing what it had promised to do, while the company assumed that its corrosion inspection work was adequate because the agency had approved the plan.

The agency's arm's-length regulation and the company's casual attitude about cleanup of boric acid crystals that could lead to corrosion resulted in an unprecedented situation - a rust hole all the way through the reactor's 6½-inch-thick steel lid.

Boric acid normally present in the reactor's coolant leaked onto the reactor lid over eight years, and the company failed to completely remove it. Only a thin stainless steel liner kept the high-pressure radioactive coolant in the reactor.

Had the cladding burst, the coolant would have geysered into the reactor containment building, creating the worst American nuclear accident since Three-Mile Island in 1979.

Workers discovered the rust hole March 5 while the plant was down for refueling, inspection and repairs. Davis-Besse, about 25 miles southeast of Toledo in Oak Harbor, has been idle ever since and won't be restarted until at least the end of the year. While the company is spending up to $200 million to buy electricity, replace the reactor lid and repair the plant, there are multiple investigations by the NRC, FirstEnergy and Congress to find out how the unthinkable could have happened and who's to blame.

The damage to the reactor lid after years of neglect "would seem to undermine confidence in both the plant owner and the NRC," said David Lochbaum, nuclear safety engineer for the Union of Concerned Scientists.

The UCS plans today to formally ask the NRC to explain why it approved Davis-Besse's flawed boric acid cleanup plan and then did not follow up to verify the company was doing what it said it would do.

"That is one of the things we are looking at - who knew what, when," said Edwin Hackett, assistant team leader of an NRC task force investigating whether the agency might act differently to prevent similar problems at other nuclear plants.

"It's a fair characterization that under the realm of things [the NRC] considered significant in the mid-1990s, this [boric acid corrosion prevention at Davis-Besse] would not be high on the list," Hackett said. "The safety and inspection of the plant is primarily the responsibility of the licensee. Unless otherwise indicated, the NRC's assumption is that they're fulfilling their obligations."

The NRC sent inspectors to Davis-Besse in 1989 for four days. They were there to review the plant's plans to prevent corrosion. Earlier coolant leaks at some plants had corroded critical parts that keep water under high pressure flowing around the reactor core.

The NRC thought cleanup was important but also believed the high temperature of the reactor lid - more than 500 degrees Fahrenheit - would boil away, leaking coolant. All that would be left would be dry boric acid crystals, which would be harmless if they did not get wet or accumulate. The industry and the agency assumed no plant operator would allow acid powder to remain on the reactor lid.

A 1990 study commissioned by Davis-Besse's then-owner, Toledo Edison Co., and two other utilities, recommended the crystals be cleaned up before there was a chance for them to be "rewetted" and become more caustic. It warned that rust-colored crystals were a sure sign that steel was being corroded.

"In this instance, the area should be cleaned, thoroughly inspected, and repairs made when necessary," the study said.

"We are investigating that study," FirstEnergy spokesman Todd Schneider said yesterday. "Who had this knowledge? Why was it not shared or implemented?"

Schneider also cast doubt on the adequacy of Davis-Besse's long-standing boric acid inspection and corrosion prevention plan.

"We are investigating whether it was well-designed or implemented correctly," Schneider said. "There is a span of several years where we missed some obvious signs."

The NRC itself declared that parts of the Davis-Besse inspection program were unsatisfactory in its 1990 audit of boric acid cleanup plans at 10 nuclear plants. The agency gave Davis-Besse low marks for its inspectors' training and their procedures for judging damage.

Although only two plants received lower overall scores, the agency still deemed Davis-Besse's program acceptable.

"The NRC knew it was bad and accepted it that way," said Lochbaum.

NRC inspectors based at the plant did not specifically look for corrosion on the reactor lid because the agency presumed that corrosion could never be so extensive as to eat through the lid - assuming Davis-Besse was following its boric acid corrosion prevention plan.

"There are a lot of things for inspectors to oversee," said Hackett. "It should have been on their list, but it would have been low on the list."

Lochbaum, who has worked at several nuclear plants, concedes that NRC inspectors have a lot to do. But he faults the agency's basic premise that reactor lids stand virtually no chance of being breached. Thus, NRC inspectors have to give corrosion a higher priority, he said.

Over the years plant workers regularly saw reddish brown boric acid deposits on the reactor head. An NRC investigation conducted after the shutdown found that cleaning efforts were incomplete, highly inconsistent and in some cases undocumented.

In May 1998, workers said they removed the corrosion "as best as we can," according to plant records. In April 2000, "lava-like" brown crusts of boric acid more than an inch thick blanketed much of the reactor lid. Workers banged away the rock-hard material with crowbars and sprayed it with high-pressure washers but did not record how much was left and what damage might have been done.

Beginning in 1990, the company's engineers failed to convince the plant's management that the service platform inches above the reactor head should be altered to allow workers to better inspect the lid. Engineers wanted to cut larger "peepholes" in the skirt of the support structure, which supports the reactor's control rods.

Managers repeatedly rejected the idea, even though all but one of Davis-Besse's sister plants had made the changes. The company reasoned that its inspection techniques - which the NRC had approved - were adequate, and that it had not promised the agency that workers would do more thorough inspections.

Lochbaum argues that the NRC should share blame for that kind of thinking. "Say I'm the guy controlling whether that modification is done or not at Davis-Besse. The thing costs $250,000. On the other hand, the NRC tells me my existing [inspection] program is adequate. Do I pay for something to make adequate better? It may be the reason he did not make that call."

Whatever its past mistakes, FirstEnergy pledges it will change. "I'm pretty confident that we are not going to tolerate [boric acid] crystals on [the] head," Schneider said.

Lochbaum said it is important that both Davis-Besse and the agency show a new attitude. "The company and the NRC could demonstrate with deeds rather than words that this is a learning opportunity. Or they could sustain the business-as-usual attitudes that created this near-disaster."

To reach these Plain Dealer reporters:

jmangels@plaind.com, 216-999-4842

jfunk@plaind.com, 216-999-4138