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lchic - 08:24pm Apr 28, 2002 EST (#1858 of 1866)
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LAXITY : Laxity cited in corrosion of reactor head at Davis-Besse power plant

04/06/02 / John Funk / Plain Dealer Reporter / Oak Harbor, Ohio

- The Nuclear Regulatory Commission yesterday sharply criticized FirstEnergy Corp. officials for overlooking evidence of corrosion that ultimately crippled the Davis-Besse nuclear power plant.

"Davis-Besse had several opportunities [in the last decade] to clean and inspect the reactor head and did not do it," Jack Grobe, director of reactor safety in the NRC's Midwest region, told an audience of 500 from the auditorium stage at Oak Harbor High School. Davis-Besse's top management listened from the other side of the dais.

The corrosion created a large hole in the reactor's head that left only three-eighths of an inch of stainless steel between the inside of the reactor and the containment vessel it sits in - "an unacceptable margin of safety," said Jim Dyer, the NRC's regional administrator.

FirstEnergy officials have emphasized that the corrosion did not lead to radiation leaks or pose a health hazard.

"We could have and should have found [the problems] earlier," Howard Bergendahl, FirstEnergy Nuclear Operating Co. vice president at Davis-Besse, said in response. "We were mistaken. Our job is to expect the unexpected. We did not do this."

NRC officials, addressing the public meeting held to disclose preliminary results of their investigation, said this is only the fact-finding phase. They left open the possibility that FirstEnergy could face sanctions.

Davis-Besse, which is on Lake Erie about 22 miles east of Toledo, has been shut down since Feb. 16 for refueling and an inspection ordered by the NRC after similar plants developed cracks in critical control-rod mechanisms.

The 45-minute report detailed what the NRC's special inspection team found last month - both in Davis-Besse's records and on the heavily damaged reactor head. The federal team agreed with company's findings on the corrosion's cause: Boric acid leaked from the reactor through the cracks and ate a 4-to-5-inch-by-7-inch hole nearly through the 6-inch-thick solid steel reactor cap.

The cap, or head, measures 17 feet in diameter and weighs 150 tons. It is lined with stainless steel, which is impervious to boric acid. But the corrosion, going on at least since 1999, rusted out about 35 pounds of the head's carbon steel, the NRC team calculated.

After the Davis-Besse corrosion was found, the NRC asked the operators of all 68 reactors of similar design to submit inspection records. So far, the Davis-Besse "wastage" is the only case of significant corrosion.

FirstEnergy officials are proposing that the hole be sealed with a stainless steel plug and that the plant be restarted by July while it waits as much as two years for a new head it has ordered from overseas. Some groups want the plant to stay closed until the new head arrives. Others are calling for the plant's permanent closure. The NRC must approve any changes.

Brian Sheron, NRC associate director of licensing, said that if the commission had known what it knows now about Davis-Besse's past inspections it would not have allowed Davis-Besse to operate six weeks beyond a Dec. 31 inspection deadline.

FirstEnergy last fall persuaded the NRC that the plant could safely operate until Feb. 16. The company wanted to run the reactor until April 1, but the NRC wanted the control-rod mechanisms inspected for cracks.

The NRC special team's findings include:

In 1990, Davis-Besse engineers proposed modifying the insulation and service structure that hangs above the domed reactor head to give workers room to clean and inspect the top of the reactor head. The company never made the modifications. The structure, with insulation on its bottom, is two inches from the head at its center - making cleaning and inspecting difficult.

The Davis-Besse reactor was le

lchic - 08:26pm Apr 28, 2002 EST (#1859 of 1866)
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The Davis-Besse reactor was leaking boric acid for years. Acid crystals were not removed from the very top of the head in a 1996 inspection because of the closeness of the insulation and service structure. By 1998, boric acid crystals covered the head and had turned from white to brown, indicating rust.

Boric acid crystals and ferrous oxide (rust) dust were so thick in the reactor's containment building by May 1999 that the company installed filters on its radioactive monitoring equipment. By November 1999, the filters had to be changed every other day, and cooling coils on air-conditioning equipment had to be cleaned frequently.

In 2000, workers had to use crowbars and hot water to clean the hardened "lava-like," rusty boric acid from the reactor top. Because of the closeness of the insulation and service structure, they did not clean the center of the head- where several sleeves for control-rod drive mechanism were cracked and leaking.

"The delay in the modifications of the service structure played a key role" in the corrosion, said Grobe.

"Davis-Besse staff assumed the extra boric acid was due to flange leakage [a harmless leak high above the reactor head] and the color due to the age of the deposits on the air coolers," he said. "The NRC believes it was a sign of corrosion to the head."

FirstEnergy spokesman Todd Schneider said the modifications to the service structure and insulation were on the company's work list at several refueling outages but were pushed back because other work had to be done and because no one in the industry at the time believed such acid leaks were a safety problem.

"Looking back, it [the modification] might have helped us prevent today's problems," he said.

Many in the audience were critical of the company and the agency.

"Why should we have any confidence in either FirstEnergy or the NRC?" asked former NRC inspector Howard Whitcomb. He said the NRC should not accept FirstEnergy's proposal to fix the corrosion with a stainless steel patch. Instead, he said, it should idle the plant for two years until a new reactor lid is made.

FirstEnergy has said it would cost $10 million to $15 million a month to buy power during the outage.

Others spoke in defense of the company.

"Nuclear energy is the most efficient and the cleanest," said Elizabeth Wharry, who lives 3 miles from the plant. "If you listen to this hysteria and try to close the plant, you'll be throwing the baby out with the bathwater." 2002 The Plain Dealer

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