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Regional News
| Article published Wednesday, May 7, 2003
Besse’s unlike leaking Texas reactor, say
regulators
By TOM HENRY
BLADE STAFF
WRITER
PORT CLINTON - Davis-Besse was designed
differently from a South Texas nuclear plant that recently became
the nation’s first to report a small leak in the bottom of its
reactor, a Nuclear Regulatory Commission official said at Camp Perry
yesterday.
"There’s not a direct correlation at all between
South Texas and Davis-Besse," said Jack Grobe, chairman of the NRC’s
oversight panel for Davis-Besse.
Despite the subtle
differences, though, the NRC left little doubt at its monthly
Davis-Besse meeting that it is growing increasingly wary of the
potential for more wear-and-tear issues affecting the aging nuclear
industry.
The agency has not received an application for a
new plant since the Three Mile Island accident in 1979. The industry
is growing older with no modern fleet of plants being built as
replacements, despite America’s rising energy needs.
Many of
the industry’s metal-fatigue issues have received heightened
scrutiny from the NRC the past 14 months in the aftermath of its
admitted oversight lapse at Davis-Besse.
The Ottawa County
plant, 25 miles east of Toledo, has the dubious distinction of being
the site with the most corroded reactor head in U.S. nuclear
history. And regulators keep asking themselves if Davis-Besse was an
anomaly or a symptom of an emerging problem.
Davis-Besse’s
reactor head was 25 years old when the near-hole in it was
discovered March 6, 2002. Since then, several plants with aging
reactor heads have made or stepped up plans to have new lids
installed, to avoid being caught in the same situation as
Davis-Besse.
At the St. Lucie plant in Florida, cracks were
found recently in welds holding two reactor-head nozzles. Neither
leaked reactor coolant, the problem at Davis-Besse.
One crack
had worked its way through 40 percent of the weld, making regulators
wonder how much longer before a leak would have developed. That
complex has notified the NRC of plans to replace lids covering two
reactors, officials said.
More cracks were found recently in
reactor-head nozzles at the Oconee complex in South Carolina,
prompting the operator there to announce plans for three new reactor
heads. Reactor heads also are being replaced at nuclear plants in
Virginia, the NRC said.
Scientific detective work on the top
of Davis-Besse’s reactor was still in progress last summer when
regulators began shifting some of their attention to the vessel’s
underbelly. Heavy rust stains were found there. FirstEnergy Corp.
has attributed at least some of it to residue from its periodic
washings of the reactor head.
The utility has said it doesn’t
believe the bottom of Davis-Besse’s reactor is leaking, but has
acknowledged that it can’t rule out that possibility unless the
bottom shows no leaks during a week-long, high-pressure test. That
test has been delayed indefinitely as other repairs and
modifications for restart are made.
On April 18, the South
Texas plant reported the apparent leak of its reactor bottom. It
found a couple of small clusters of boron, an additive in the
reactor. The largest cluster was described as the equivalent of half
an aspirin in size.
The leak is tiny: Tests show the residue
might have begun to form as long as four years ago, said Brian
Sheron, the NRC’s associate director for project licensing and
technical analysis.
The NRC is awaiting results of an
investigation into the root cause of that leakage before taking its
next step, Mr. Sheron, one of the agency’s senior officials,
said.
Also yesterday, the NRC learned FirstEnergy is still
likely weeks away from deciding how it will address design problems
with some vital safety equipment: Davis-Besse’s pair of
high-pressure injection pumps.
The pumps would be used to
inject coolant water over the reactor in the event of a nuclear
accident. The utility learned the bearings in those pumps are
susceptible to malfunctioning if they encounter debris, based on the
way the pumps are built.
Lew Myers, chief operating officer
of FirstEnergy’s nuclear subsidiary, said a decision to repair or
replace those pumps likely won’t occur until results come back from
a simulated test. The test is to show the NRC how the pumps could
work if their design was modified.
For earlier stories
on Davis-Besse, go to www.toledoblade.com/davisbesse.
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