POSTED: 12:37 p.m. EST March 30, 2003
Plant engineers have found a flaw in high-pressure
emergency pumps at the Davis-Besse nuclear plant supposed to keep
fuel from melting in an accident, The Plain Dealer
FirstEnergy Corp., which hopes to
restart Davis-Besse in April or May, must decide whether to modify
the pumps or replace them, which would take several weeks, said
Davis-Besse spokesman Richard Wilkins.
Replacing the pumps is the most expensive option, costing as
much as $3 million, but it could be the most practical solution, he
Whatever option is taken, the work will be done while in
conjunction with other projects to reduce the plant's down time, he
The plant along Lake Erie near Toledo has been shut down
since February 2002. A month later a leak was discovered that had
allowed boric acid to eat nearly through the 6-inch-thick steel cap
covering the plant's reactor vessel.
The Nuclear Regulatory Commission is aware of the pump
problem and will review the appropriateness of whatever action
FirstEnergy proposes, said agency spokesman Jan Strasma.
Engineers determined several weeks ago during FirstEnergy's
review of Davis-Besse's design documents that the high-pressure
emergency pumps are vulnerable to fouling from debris.
It's possible that some particles might be small enough to
pass through the high-pressure pumps' filters, damage their bearings
and cause the pumps to fail. There is no backup.
The emergency pumps are part of a system to keep the hot,
radioactive reactor core supplied with coolant in case of a rupture.
Davis-Besse is the only plant in the nation whose emergency
high-pressure pumps are designed this way, Strasma said.
A smaller-scale design review by the plant and the Nuclear
Regulatory Commission in the 1990s failed to identify the emergency
pumps' weakness. While it took nearly two decades to identify the
problem, it is better to know late than not at all, said David
Lochbaum, a nuclear safety engineer with the Union of Concerned
Scientists, a watchdog group.
Lochbaum praised the Davis-Besse engineers' ability to spot
such a subtle problem, and their willingness to bring it to the
NRC's attention regardless of cost or schedule pressures.
"This is a good catch," he told The Plain Dealer
Davis-Besse "ought to get more credit for catching it than blame for
missing it earlier."
The pumps' potential to seize up in a crisis is the second
long-standing safety defect in the emergency cooling system that
plant engineers recently have identified.
In December, they reported that Davis-Besse's undersized sump
could have been clogged with debris during an accident, choking off
the flow of water to cooling pumps.
Copyright 2003 by The Associated
Press. All rights reserved. This material may not be published,
broadcast, rewritten or