U.S. finds no widespread corrosion at nuclear plants

[Susan L Gawarecki <loc@icx.net>]

U.S. finds no widespread corrosion at nuclear plants 

By Tom Doggett, Reuters

Thursday, April 11, 2002



WASHINGTON — A U.S. government-ordered review of more than five

dozen nuclear power plants has not found any corrosion in reactor caps

similar to that at the Davis-Besse facility in Ohio, a top U.S. energy

official said on Wednesday. 



The Nuclear Regulatory Commission (NRC) launched an investigation

last month after a corroded cavity was found in the reactor vessel head

of the 25-year-old plant owned by FirstEnergy Corp . The agency ordered

68 other similar reactors — more than half of the nation's 103 nuclear

plants — to look for similar problems. 



"I am not aware of any other problems they found," said U.S. Energy

Undersecretary Robert Card, adding that he had been briefed by NRC

officials on the matter. 



"Thus far, there haven't been any surprises or safety issues in the

nuclear plant review," said an NRC spokeswoman. 



Card, who was attending a meeting of the National Petroleum Council,

said the Energy Department was worried that if serious corrosion had

been detected, some of these reactors could have been shut down for

up to a year. That was because the companies that make the huge

metal reactor caps were already behind in filling other orders. 



He also said the department was worried that shutting down nuclear

plants would have caused a spike in natural gas prices, as utilities

would be forced to ramp up generation at plants that run on natural

gas. "If half the nuclear fleet went down for six months, you'd nearly

double the natural gas need. It can't be done," he said. Natural gas

provides 15 percent of electricity generation, nuclear power accounts

for

20 percent, and coal about 50 percent. 



During a scheduled refueling outage at the Davis-Besse plant that

began Feb. 16, FirstEnergy engineers found boric acid had leaked at the

base of several of the control rod nozzles that penetrate the reactor.

Boric acid is used in the primary coolant bath surrounding uranium rods

in the reactor core. 



At one of the nozzles, the acid had eaten all the way through the

vessel head, which was 6 inches (15 cm) thick. The vessel head is a

massive piece of carbon steel 17 feet (5.2 meters) wide that is bolted

down on top of the reactor to prevent any radioactive material from

escaping. The corrosion was so severe that a stainless steel liner

3/8-inch (1 cm) thick inside the reactor was the only barrier left

between the reactor core, which operates under enormous pressure, and

the metal shroud surrounding the reactor vessel. 



FirstEnergy representatives met on Wednesday with officials from the

NRC to discuss proposed repairs at the Davis-Besse plant. Agency

approval is needed before work could begin. 



The company wants to cut the most damaged area at the top of the

reactor head and cover it with a stainless steel plate. The plate would

be 12 to 13 inches in diameter, about five inches thick, and weigh

between 300 to 400 pounds. It would be welded in place using robotic

equipment. 



-- 

.....................................................

Susan L. Gawarecki, Ph.D., Executive Director

Oak Ridge Reservation Local Oversight Committee

We've moved!  Please note our new address:

102 Robertsville Road, Suite B, Oak Ridge, TN 37830

.....................................................

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