The structures around the 284 East Power House in central Hanford came crashing down Friday.
It was a repeat of the explosive demolition of the power house's near twin, the 284 West Power House, two weeks ago -- except Friday's was larger. The east power house had an additional filtration structure and a coal silo.
Crews at the 284 East Power House demolished two 250-foot-tall exhaust chimneys, three 90-foot-tall air filter structures and the coal silo. In addition, they brought down a nearby water tower, one of two familiar to Hanford workers for their "Work Safely" signs.
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The power houses burned coal to provide heating and power for buildings in the 200 West and 200 East areas, including offices and the huge buildings called canyons built to separate plutonium from uranium fuel irradiated at Hanford's reactors. The plutonium was produced for the nation's nuclear weapons program.
The two power houses were built in 1943 as part of the Manhattan Project but have not been used since the 284 East Power House shut down in 1994.
The Department of Energy and its contractor, CH2M Hill Plateau Remediation Co., settled on explosive demolition as the most economical and safest way to bring down the tall support structures. It limited tasks that workers needed to do high above the ground and reduced the use of heavy equipment in a congested area.
"These explosive demolitions draw a lot of attention because of their spectacular nature, but for us it's simply a safe and efficient method of getting these support structures out of the way," said Mike Swartz, CH2M Hill decommissioning and demolition deputy project manager, in a statement.
To prepare for the work, oxygen torches and demolition equipment were used to separate the stacks and air filter structures -- called baghouses at Hanford -- from the power houses. They also weakened the structures, similar to cutting a wedge into a tree, to make sure they fell according to plan.
Getting the support structures down clears the way for demolition of the two power houses. Asbestos removal began inside the 284 West Power House after the February explosive demolition of its tall support structures and asbestos already had been removed from the 284 East Power House.
They contain no radioactive contamination and will be torn down with an excavator and shears. CH2M Hill is on schedule to remove the two 53,000-square-foot power houses by the end of September.
"Recovery Act funds allowed us to accelerate the schedule for removing the power houses," said Al Farabee, DOE project director. Hanford received $1.96 billion of federal economic stimulus money, including $1.6 million for the explosive demolition work.
Demolition of the power houses were added to CH2M Hill's work assignment when the Recovery Act money was received in April 2009. It was part of $24 million in work to demolish more than a dozen obsolete industrial structures in the area to reduce overhead and maintenance costs.