FirstEnergy Corp. neglected to tell federal regulators last fall about
years of evidence of rust at the Davis-Besse Nuclear Power Station, a
company spokesman acknowledged yesterday.
Now the company says the rust - detected in filters as early as 1999 -
is strong circumstantial evidence that the reactor head was being corroded
by concentrated boric acid that had leaked out of the reactor.
FirstEnergy reported on March 11 that it had found a large hole eaten
nearly through the 6½-inch-thick carbon steel head.
"It [rust] was not a reportable event for the Nuclear Regulatory
Commission," FirstEnergy spokesman Todd Schneider explained last night.
"There are certain thresholds that you report to the NRC. This
situation was not one of them."
In a report made public Monday, FirstEnergy engineers said they were
aware of the rust and leakage but did not realize its significance.
The NRC in an Aug. 3 bulletin had asked FirstEnergy and other utilities
to start inspections of the heads of similar reactors by Dec. 31 for
cracked nozzles.
The Akron power company successfully argued that it should be allowed
to operate the reactor until mid-February.
The NRC suspected there might be cracking problems at Davis-Besse and
11 other older power plants that operate pressurized water reactors.
The inspection has since been expanded to a total of 69 similar
reactors, including Davis-Besse.
The company argued that previous inspections had not detected cracks in
the control rod sleeves - tubes that allow boron rods to pass through the
head and into stacks of radioactive fuel, controlling the reaction.
But by March 11, FirstEnergy reported it had not only discovered cracks
in five of the sleeves but also a large hole in the center of the 6½-inch
carbon steel head, leaving only a ~-inch thick stainless steel cladding on
the inside of the head to keep the coolant inside the reactor.
David Lochbaum, an engineer with the Union of Concerned Scientists,
said the rust and boric acid deposits "should have made bells and whistles
go off."
"Boric acid [normally in the reactor coolant] is not supposed to be on
top of the reactor," he said. "These were signs that something was wrong.
This [the company's response] is troubling.
"I'm not trying to blame anyone," Lochbaum added. "I don't think this
was willfully withheld from the NRC. But it is only after the fact [of
corrosion] that they could say, Oh, yeah, that was important.' "
NRC spokesman Jan Strasma yesterday declined to comment on the
company's omission of what turned out to be crucial evidence that the
reactor head had significant leaks and something was rapidly rusting.
"We are in the middle of an investigation. We still have inspectors
there," said Strasma. "That is the whole point: What information was
available to indicate that they had a problem, and how did they deal with
that information?"
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