Thursday, March 3, 2011

Explosives to bring down Hanford towers

Seattle Times: Explosives to bring down Hanford towers
A number of tall industrial structures at the former Hanford Nuclear Reservation in Eastern Washington will come down in a spectacular fashion Friday, courtesy of federal stimulus funding.

U.S. Department of Energy contractor CH2M Hill Plateau Remediation Co. will use explosives to demolish the 284 East Power House's two 250-foot-tall exhaust chimneys, two 90-foot-tall air filter structures, a coal silo, and a 140-foot-tall water tower. On Feb. 18, similar structures at the 284 West Power House were demolished in the same manner.

The low-rise power houses will be demolished using conventional means.

The $1.6 million cost is being paid for with American Recovery and Reinvestment Act money, said Cameron Hardy, a spokesman with the Department of Energy, which is overseeing the ongoing environmental cleanup at the former nuclear reservation.

The power houses were built in 1943 as part of the Manhattan Project, burning coal to provide steam for chemical processes that were part of Hanford's plutonium-processing mission in support of national defense, as well as space heat for nearby offices and other facilities, according to the DOE.

The air filter structures, known as baghouses, were added in the early 1980s to reduce pollution from the stacks. The 284 West Power House went out of service in 1992 and the 284 East Power House went out of service in 1994. The water tanks were disconnected in 1998.

Kurt Kehler, vice president for decommissioning and demolition with CH2M Hill Plateau Remediation Co., said that if the chimneys weren't imploded, scaffolding would have to be built on what is the equivalent of a 25-story building or a climbing platform would need to be used. That could be risky to workers at those heights, he said.

Based on precise calculations, workers used oxygen torches and demolition equipment to loosen the chimneys and air filter stacks from the power houses.

"No matter what the structure is, you do engineering calculations to determine how to appropriately weaken the structure and collapse (it) in a certain direction and in a certain way," said Kehler. "The structures that we want to come down, come down, and the structures that we want to stand, stand."

What makes this project different from one outside of Hanford is the "safety culture" at the former nuclear reservation, Kehler said.

At the Department of Energy site, any employee can ask that a project be halted if they have safety concerns, he said.

"We allow anybody to raise the stop-work flag in the chance that they might be right," he said. "That means the janitor could stop me from blowing up the stacks because (he is) concerned about the (potential for contaminated) dust in the air."


Kehler said each concern is checked out. There is such a strong safety culture "because we're the Hanford Nuclear Reservation, because we've been in business since the Manhattan Project started and the safety concerns and the safety controls to the environment weren't very stringent back in the early days."

Roads and buildings on the Hanford site have been closed temporarily near the demolition to ensure worker safety, the DOE said, and demolition is on days when there are fewer Hanford workers expected on site.

Hardy said the structures being demolished "weren't radiologically contaminated so they weren't previously an item that we were rushing to take down."

But, because they don't have that type of contamination, they can be demolished relatively quickly, making the project eligible for federal stimulus funding, he said.

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