Hanford workers are preparing to start next week digging up radioactive and chemical waste that could spontaneously catch fire when exposed to air.

“We’re planning for the worst case,” said John Darby, project manager for the Department of Energy’s contractor, Washington Closure Hanford.

The 618-7 Burial Ground was used from 1960 to 1973 for waste from the Hanford nuclear reservation’s 300 Area just north of Richland where fuel was made for Hanford’s reactors and research was conducted.

“Burial grounds like this don’t have a lot of documentation,” said Stacy Charboneau, DOE deputy assistant manager for Hanford cleanup along the Columbia River.

When the waste was disposed of, it was not expected to be retrieved to meet future environmental standards. But Washington Closure has developed a list of the hazardous items it needs to be prepared to handle there, starting with hundreds of barrels of metals in liquids to keep out air that could start a fire.

It expects to find drums of depleted uranium chips likely left from research work.

Workers also will be on the lookout for drums of zircaloy or beryllium shavings, both metals used in the cladding or capping of N Reactor fuel.

The drums likely were filled with oil or water before they were buried. But if they have corroded, the liquid may have leaked out and could leave the contents vulnerable to spontaneously igniting when exposed to the right temperature and oxygen.

“We will be using aggressive controls,” Darby said.

Workers will be bringing up the barrels one at a time from behind blast shields and wearing full radiation protection gear and supplied air respirators. They’ll also expose no more than four drums at a time during the excavation to limit any potential fire.

Intact drums will be opened with remotely operated equipment inside an enclosure so more water or mineral oil can be added to stabilize them. Contaminated soil where barrels have leaked will be mixed with a fixative to prevent airborne contamination.

Piles of sand already stand ready at the burial ground to quickly smother any fire.

Washington Closure believes chances of a fire are slim, in part because of the size of the chips they expect to unearth. But similar material has caught fire at Idaho and Tennessee nuclear sites.

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