Plans are being developed to start cleaning up Hanford's largest waste site later this year.
It's the 13-square-mile "BC controlled area" near central Hanford, which is spotted with radioactive cesium 137 and strontium 90 even though none of Hanford's work to produce plutonium for the nation's nuclear weapons program was done there.
But it is just south of the BC cribs and trenches where 50 million gallons of liquid waste contaminated with radioactive salts were discharged during the Cold War. Animals attracted to the salts spread the waste across miles of the Hanford desert.
"This area has a large spread of contamination on the surface with the ability to move around with our winds," said Matt McCormick, Department of Energy assistant manager for central Hanford cleanup.
An engineering analysis prepared by Fluor Hanford for DOE concluded that the surface soil in contaminated spots should be dug up and hauled to a lined landfill for low-level radioactive waste a few miles to the west. DOE, the Washington state Department of Ecology and the Environmental Protection Agency are taking public comment on the plan until March 26.
Then work could begin to dig up soil later this year. The proposal estimates that about 237,000 cubic yards of dirt will need to be dug up in cleanup work that could take three years.
"Ecology strongly supports it for three reasons," said John Price, environmental restoration manager for the Department of Ecology.
Digging up the contamination will have the immediate benefit of reducing risk to plants and animals. It also contributes to the goal of shrinking the contaminated area of the Hanford nuclear reservation to a central industrial zone around the 200 East and West areas that will remain a radioactive waste disposal area.
And the contaminated soil is needed now, Price said. The landfill for low-level radioactive waste, the Environmental Restoration Disposal Facility, requires three parts soil to be mixed with one part debris to get good compaction to make sure the landfill remains stable far into the future.
The large amounts of soil to be dug up will prevent clean soil from having to be used at the landfill to mix with building rubble during the fast pace of building demolition along the Columbia River at Hanford.
Fluor found during surveys of radiation that about 140 acres closest to the BC cribs and trenches have continuous contamination from six inches to a couple feet deep, Price said. About seven square miles of the BC controlled area have about 750 hot spots of contamination that will need to be dug up. Price described them as varying from "as big as your kitchen table to your backyard."
The southern portion of the area doesn't appear to have any contamination, although its been posted as part of the controlled area as a precaution.
The BC cribs and trenches were built just south of the 200 East Area in central Hanford in 1955 and received waste mostly from a program to reprocess waste from B Plant and T Plant to recover uranium. The reprocessing was done at U Plant with liquids disposed of in the underground cribs or surface trenches.
Animals were attracted to the salt, spreading the contamination, and as coyotes ate smaller contaminated animals their droppings further spread the waste.
Public comment on the proposed cleanup plan may be sent to Larry Romine, DOE, Richland Operations Office, P.O. Box 550, A6-33, Richland, WA 99352, or e-mail to Larry_D_Romine@rl.gov.
* On the Net: Link to the engineering analysis at www5.hanford.gov/hanford/eventcalendar
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