CARROLL TOWNSHIP -- The Davis-Besse Nuclear Power Station likely
would have been at greater risk during an accident because of a
faulty design dating back to its creation, said federal regulators
Thursday.
The Nuclear Regulatory Commission is still considering the safety
impact of faulty high pressure injection pumps, a safety system that
would help cool the nuclear reactor in the event of an emergency.
Commission officials on Wednesday asked Davis-Besse parent
company FirstEnergy for more information before making a final
determination. The NRC rates problems with safety in terms of
colors, green for very low significance, then white to yellow before
reaching red as the highest level of significance.
The NRC chairman of an oversight panel watching Davis-Besse's
progress, Jack Grobe, wrote in a letter to FirstEnergy that "the
preliminary safety significance of the inspection ... is Greater
than Green." An enclosure with the letter stated, however, that the
assessment could be as high as red.
Grobe asked for further analysis, including the failure prob-
ability of the HPI pumps when recirculating coolant water and the
possibility for increased risk because of fires.
Plant spokesman Richard Wilkins said the preliminary assessment
was neither a surprise nor anticipated by the company.
"I think a lot of people have looked at the HPI pumps and the
modifications, and there's a lot of different conclusions on whether
or not they would have operated had they gotten some kind of debris
in them, and how much debris it would have taken for them to fail,"
he said.
Wilkins added the assessment won't affect the company's timeline
for finishing up repairs to the plant, which is now set for the end
of November.
The problem with the HPI pumps became apparent about a year ago
at the off-line plant, when workers determined bearings in the pump
were much smaller than any debris that could be flowing through in
the coolant water.
Plant workers estimated there would be some debris in the event
of an accident in recirculated water. That debris could include
fibrous insulation, paint, concrete and containment floor dirt,
among other things.
That debris could clog up the bearings, causing the pumps to fail
from "excessive vibration, overheating or both," Grobe wrote.
It was determined the design flaw dated back to when the plant
was built.
Wilkins said one of the HPI pumps has been sent to a facility in
Pittsburgh for modification -- something that has been planned for
several months now -- and another one is expected to go by early
next week.
NRC officials have said the HPI pumps are one of several issues
that need to be resolved before the plant can restart.
It has been shut down since February 2002, when workers found
corrosion on the reactor head. Since then, FirstEnergy officials
have found more problems that needed to be corrected prior to
restart. They are maintaining a late November completion date, but
NRC officials continue to say the plant will only restart when they
are satisfied with the safety margin.
