Published Friday, March 9, 2001 Federal agency: Water levels fell too low at nuclear plant

By Kevin O'Hanlon The Associated Press

LINCOLN -- The Nebraska Public Power District is investigating a March 3 mishap at its Cooper Nuclear Station near Brownville where water levels fell to unusually low levels in the reactor's cooling system.

The Nuclear Regulatory Commission confirmed Friday that water levels fell too low while the plant's generating power was being reduced. Problems then arose in trying to use pumps to bring the water levels back up.

"The operators always maintained the reactor within safe bounds, but our concerns were that operator performance was not up to standards. said David Loveless, a commission spokesman. "The swings in the water levels they got were not normal."

The public was never at risk, said Dave Simon, a spokesman for the power district.

"We are reviewing both the event and the human side," he said. "We'll look at ... the role that people's performance played and if we need to prescribe any corrective action."

Loveless said water levels in the plant are given numerical values ranging from 1 to 8, with 8 being the highest. Level 2 is when an emergency cooling system kicks in.

"Level 1 is still a considerable distance above the top of the core," Loveless said "They never got much below Level 3 during the event."

He said the risk to the public was "nominal."

Emergency procedures go into effect when the water drops below Level 1. If water levels fall that low, the reactor's core could overheat and lead to the release of radioactivity.

Water inside the cooling system dropped for 45 minutes, during which time one pump failed, Loveless said. A second pump failed to operate properly so operators finally used a third pump to restore the water levels, he said

"But they didn't use it, in my personal opinion, early enough," Loveless said. "This leads us to question operator performance and that's what we're looking at now -- it was not up to standards."

The agency will wait for the power district to conduct its review before deciding what, if any, action to take.

NPPD has operated the Cooper plant, the state's largest power generator, for 26 years.

The state's only other nuclear plant is operated near Fort Calhoun by the Omaha Public Power District.

The two plants were among 13 in the nation found to have no significant performance problems in a federal report released in December.

Both plants' federal licenses are set to expire 2013, but both utilities are considering applying for 20-year extensions.

http://www.theindependent.com/stories/030901/new_nuclearwater09.html

-- Martin Thompson (mthom1927@aol.com), March 11, 2001