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Regional News
| Article published Wednesday, January 1, 2003
Davis-Besse woes help spur nuke-plant
confab
By TOM HENRY
BLADE STAFF
WRITER
GAITHERSBURG, Md. - Pro-industry lobbyists
portray Davis-Besse’s massive rust problem as an anomaly, but
federal officials want to know whether it is a harbinger of things
to come among the world’s aging fleet of nuclear
plants.
Their anxiety has manifested itself in a major
three-day symposium that the Nuclear Regulatory Commission is
putting together in hopes of drawing participants from France,
Japan, and Sweden - countries that have invested heavily in nuclear
power.
The event is tentatively slated for March 24-26 at the
Marriott Gaithersburg Washingtonian, organizer Bill Cullen, an NRC
senior materials engineer, said.
On its surface, the
conference will be nitty-gritty metallurgy - a hard look at how
nuclear plants with pressurized-water reactors, such as
Davis-Besse’s, have metal components prone to crack as they age and
continue to be fatigued by extreme temperatures and
pressure.
Mr. Cullen acknowledged the NRC has a broader
purpose for the conference. In its announcement, the agency said
that the discovery of cracks and leakage from control rod drive
mechanism nozzles in several U.S. and foreign reactors, including
Davis-Besse, has "raised this issue to a high level of regulatory
concern."
"We have an aging fleet of plants with a design
that we may never see again," Mr. Cullen said. Utilities owning them
are "going to have to come to grips" with the enormous expense of
replacing heads or take other measures to protect the devices, he
said.
Davis-Besse’s problem is costing FirstEnergy Corp. in
Akron at least $350 million, mostly for replacement power the
company is buying while the plant is idle. In Virginia, Dominion
Energy announced it is spending $175 million to install new reactor
heads at its North Anna and Surrey nuclear plants. Other utilities
are contemplating similar projects.
One type of nickel-base
alloy commonly found in pressurized-water plants, Alloy 600, has
drawn the NRC’s attention for years because it is not as crack-proof
and corrosion-resistant as thought at the advent of the nuclear age,
he said.
Mr. Cullen said one of his first assignments after
joining the NRC in February was to put together an Alloy 600
conference. A month later, the deep rust on Davis-Besse’s reactor
head was discovered - the apparent result of unchecked boric acid
that had leaked for years and burned through all but a thin liner of
the cap. The discovery jolted the NRC so much that it required other
nuclear plants to prove they don’t have the same
problem.
"This is clearly an issue that has consumed the
careers of many people here at the NRC since March 7 or 8 [when it
was discovered]," Mr. Cullen said
Similar problems at other
plants - such as Duke Energy Corp.’s Oconee Unit 3 plant in South
Carolina - contributed to the NRC’s decision to hold the forum, he
said.
"While we certainly are including the head issue, it
[the conference agenda] is a little larger than that," Mr. Cullen
said.
Todd Schneider, FirstEnergy spokesman, acknowledged
yesterday Davis-Besse has made the industry rethink its position on
reactor-head nozzle cracks.
"Before Davis-Besse, the thinking
was that boric acid on the reactor head was acceptable," he said.
"The situation at Davis-Besse hopefully will provide some insight to
prevent it from happening again."
The NRC had seen hairline
cracks in reactor-head nozzles since 1988, but the cracks found at
Oconee Unit 3 in early 2001 were the first in a horizontal, circular
pattern - far more dangerous than axial, vertical cracks because
they can weaken tubes and allow them to pop off like champagne
corks. Reactor heads have 69 such nozzles.
If any break
apart, the result could be the same as a hole in the reactor head:
The containment building, the public’s last line of defense, could
be instantly filled with radioactive steam, officials have said.
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