04/04/03

Potentially flawed emergency pumps continue to bedevil engineers at the idled Davis-Besse nuclear plant, and the search for a solution is throwing the reactor's restart timetable into doubt.

FirstEnergy Corp. says it hopes to do the work within its current schedule, aiming to have the plant ready by May. But resolving the pump issue could take weeks. The company has pushed back Davis-Besse's restart date more than half a dozen times in the last year.

The company prefers to replace the questionable pumps rather than modify them. However, its engineers must first figure out whether new pumps - which are larger, pump with greater force, and consume more electricity - would be compatible with the plant's existing electrical and piping systems. They will then need more time to draw up installation plans and do the actual work.

"It's looking like analysis of this is going to be a lot more detailed than we originally thought," said Davis-Besse spokesman Richard Wilkins. "After we determine its feasibility, there will be a lot more engineering to do it."

Asked about the effect the work might have on the plant's readiness to restart, Wilkins said, "I don't know. I don't think anybody knows. But by doing the (pump) work with other things going on, the objective is to minimize impact."

Davis-Besse engineers determined several weeks ago that the two emergency coolant pumps that are intended to keep the reactor's fuel from melting in an accident are vulnerable to fouling. The engineers discovered that debris from an accident might jam the pumps' bearings, causing the equipment to fail.

The pumps' vulnerability came to light several weeks ago during FirstEnergy's intensive review of Davis-Besse's design. The review is part of the company's efforts to convince federal regulators that Davis-Besse can be operated safely again. The plant has been shut down for nearly 14 months since workers found a large rust hole in the reactor's lid.

Alternatives to replacing the pumps are beefing up their debris filters, or modifying their bearings to reduce the likelihood that they'll seize up.

The engineering study to decide the issue "is a significant amount of work, (but) I don't want to portray it as onerous," said Jack Grobe, chairman of the Nuclear Regulatory Commission panel overseeing the plant's recovery. "It's what engineers do."

The decision to replace or repair the pumps is FirstEnergy's, but the NRC must agree.

"The agency is giving this issue a significant amount of scrutiny," Grobe said. "These are important pumps."

Davis-Besse managers must prove that the pumps - whether replaced or modified - will work before engineers can attempt an important pre-start test. Plant managers plan to bring the reactor up to its normal operating pressure and temperature for a week, without allowing the nuclear chain reaction to begin, to check for leaks in the bottom of the reactor vessel.

Workers found suspicious rust stains on the reactor's sides and bottom last fall, but haven't been able to pin down their source. If leaks are found, their repair could add to the uncertainty of the restart date.

The power-up test is one of the last major hurdles the plant faces before seeking the NRC's approval to resume making electricity.

For complete coverage of Davis-Besse, go to www.cleveland.com/davisbesse/

To reach these Plain Dealer reporters:

jfunk@plaind.com, 216-999-4138

jmangels@plaind.com, 216-999-4842