February 24, 2005
KOTV

YAKIMA, Wash. (AP) _ The impact of a severe earthquake on a radioactive waste treatment plant under construction at the Hanford nuclear reservation is almost 40 percent greater than previously estimated, according to a new study.

The nearly $6 billion plant _ the federal government's largest construction project _ is being built to treat millions of gallons of highly radioactive waste left from Cold War-era nuclear weapons production.

Construction is already about 35 percent complete at the south-central Washington site. Work has been slowed or shifted to other parts of the plant while engineers re-evaluate its design.

The U.S. Department of Energy, which manages the site cleanup, and the contractor hired to build the plant stressed the chances of a severe earthquake at the site are slim.

In addition, some construction work that already has been re-evaluated _ the concrete walls at the plant, for instance _ meet the new seismic requirements and will not have to be changed.

Earthquakes, No. 1, don't happen a lot in this area, and if they do happen, we are building a very robust plant to handle it,'' Roy Schepens, manager of the Energy Department's Office of River Protection, said Thursday.

In 2002, the Defense Nuclear Facilities Safety Board raised concerns that the Energy Department had failed to adequately investigate the impact a severe earthquake might have on the plant.

The agency had gathered seismic data from the entire 586-square-mile Hanford reservation to determine the impact, but did not conduct a seismic investigation of the plant site itself.

The agency conducted a more thorough evaluation in 2004; the data were sent to a federal science laboratory for review.

The results of that review _ released first to The Associated Press this week _ found the force of the ground movements at the plant site during a worst-case-scenario earthquake would be 38 percent greater than previously estimated.

Engineers now are working to apply that new number to the plant's design; the process could take four to six months, Schepens said.

In the near term, we will develop very conservative design criteria that will allow us to advance the design and construction activities,'' he said.

Whether the new data will affect the cost and schedule of the work has not yet been determined, Schepens said.

For 40 years, the Hanford reservation made plutonium for the nation's nuclear weapons arsenal. Today, work there centers on a $50 billion to $60 billion cleanup, to be finished by 2035.

About 1,700 people have been working to build the plant, which will stand 12 stories tall and be about the size of four football fields.

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