OAK HARBOR, Ohio - The Davis-Besse nuclear power plant was getting positive marks on federal inspections in the 1990s, even as mounds of boric acid were eating a hole in the reactor vessel head, causing a safety problem that would send ripples through the nuclear industry.
As the investigation continues into how corrosion on Davis-Besse's reactor head got so bad it caused a milk-jug-sized hole, leaving only a thin stainless steel liner to cover the reactor, some of the attention is turning toward the Nuclear Regulatory Commission.
Critics and the agency itself want to know how the mounds of boric acid on the head and other signs of problems were missed at the plant.
“If the NRC can ensure these things are fixed, they'll have a greater confidence that it won't get to this point again,” said David Lochbaum, a nuclear safety engineer with the watchdog group Union of Concerned Scientists. “The NRC are kind of like the nuclear police. That didn't happen here.”
Three separate investigations are going on into the NRC's role in the reactor head corrosion, which has kept the plant shut down since February. Investigators are looking at whether warning signs were missed or if inspection procedures should be strengthened.
The Inspector General's office, an independent unit of the NRC designed to audit the federal agency, is looking into some of these questions, including what motivated the NRC to allow Davis-Besse to operate for an additional six weeks instead of shutting them down late last year when cracked nozzles were found at another plant. It was the cracking nozzles that caused the boric acid to leak, corroding the reactor head.
The NRC also formed a body, called the Lessons Learned Task Force, to look into the Davis-Besse situation and what the NRC could have done better to prevent it. Among other things, the NRC is looking into whether FirstEnergy officials deliberately gave false information on documents. The agency has already issued a proposed violation for inaccurate reports.
In addition, the U.S. House Energy and Commerce Committee, which helped Congress form the country's energy policy, is investigating Davis-Besse and the NRC to make sure the public was not endangered by the corrosion.
The NRC in 1997 called Davis-Besse one of the best-run nuclear plants in the Midwest, if not the country. It gave the plant high marks in subsequent inspections throughout the 1990s. It wasn't until recently, when the corroded head was found, that it came out that problems at the plant included a tendency by management to put production before safety and not to find and fix problems as they occurred.
That shortcoming, company officials have said, led to the corrosion problem that one former regulator has called the closest brush with disaster in the nuclear industry since the Three Mile Island incident.
At a recent public hearing, the NRC regional administrator for the Midwest acknowledged that federal regulators were not as involved at Davis-Besse in the 1990s as they should have been.
In large part, that was because the NRC - and particularly its regional office in Lisle, Ill. - was handling problems at other nuclear power plants. Four plants were going in front of the regulatory body that Davis-Besse faces now - called the 0350 oversight panel - because they had been shut down for various safety problems. One of the plants, the Clinton nuclear power plant near Clinton, Ill., did not operate for more than two years.
At the time, Davis-Besse was giving the NRC no such indications, regulators said, so the agency decided to devote its resources to the other plants. Davis-Besse was operating under the NRC's baseline inspection program, meaning it was showing no signs of safety troubles. Two resident inspectors are typically assigned to such plants.
Resident inspectors are the first line of federal oversight at nuclear power plants. They work at the plant, monitoring meetings, inspecting the plant, and overseeing workers' activities.
At Davis-Besse, the NRC has a resident inspector and a senior resident inspector. From March 28, 1999 to October 10, 1999, and again between Sept. 22, 2001, and Jan. 12 of this year, one of those spots was vacant. The longest-running resident inspector in the 1990s, who served from June, 1999, to September, 2001, was listed earlier this year as an employee at Davis-Besse.
In June, the NRC's Advisory Committee on Reactor Safeguards, an influential federal body, questioned how resident inspectors could have missed signs like 900 pounds of boric acid on the reactor head. Those questions were echoed in the most recent public hearing on Davis-Besse.
But Mr. Lochbaum said he is reluctant to criticize the resident inspectors, who have the task of monitoring activities at the entire plant.
“Just the mechanics with several hundred workers and two resident inspectors, that's just an impossible task,” he said. “They were kind of indicating the resident inspectors didn't do a good job. It would have been nice if they had caught it, but I don't think it was their fault.”
In plants that are undergoing baseline inspections, the NRC performs about 5 percent of the inspections done at the plant, Mr. Lochbaum said. The power plant is expected to complete the other inspections and report problems to the federal agency.
In addition to the resident inspectors, regional inspectors conduct occasional reviews of the plants, and specialists look at specific areas of the plants throughout the year. It is typical for specialists to complete 10 to 25 inspections a year.
Jim Dyer, head of the NRC's regional office in Chicago, said at a recent public hearing that he was worried Davis-Besse was anticipating what inspectors would look at, then making sure those areas were in compliance, much the way a student could anticipate what's on a test, then study just those areas.
Because resident inspectors don't look at every part of the plant during each check, inspections are based on risk assessments, according to Doug Simpkins, who is a resident inspector at Davis-Besse. The industry, including plant officials and regulators, developed a system in which systems at the power plant were rated based on what would cause the most risk if it failed. Resident inspectors pay the most attention to what, according to the list, poses the highest risk.
High on the list are auxiliary feedwater systems and diesel generators. The reactor head vessel was toward the bottom.
“We never thought it would happen. We didn't think it could happen,” Mr. Simpkins said. “They don't understand. We have a strict set of guidelines to follow.”
Mr. Lochbaum said the NRC needs to re-evaluate its risk assessment, which was developed around 1997.
“Things that are on the top of the list get the most attention. And nobody ever gets to the bottom of their inbox,” he said.
Mr. Lochbaum and other experts in the nuclear industry said the regulations are a system of checks and balances that are designed to catch problems with equipment or workers.
“But the problem at Davis-Besse wasn't just one worker. The NRC needs to figure out why those backups didn't work. You have to try to figure out why the safety nets weren't in play,” Mr. Lochbaum said.
Privately, some people who are active in the nuclear industry say the Nuclear Regulatory Commission cannot afford to assume nuclear power plants are evaluating themselves, and the incident at Davis-Besse proves that. Federal regulators need to constantly assess how well nuclear power plants are inspecting themselves and reporting problems, they said.
“They need to restore the public's confidence,” Mr. Lochbaum said.
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