OAK HARBOR, Ohio -- 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 and The Toledo Blade reported Saturday.

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 said.

Whatever option is taken, the work will be done while in conjunction with other projects to reduce the plant's down time, he said.

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.

Previous Stories:

• February 25, 2003: NRC Releases Findings On Power Plant's Safety
• January 16, 2003: Pills Available For Residents Near Power Plant
• October 24, 2002: Kucinich Investigates Near-Nuclear Accident