Workers close to cataloguing Hanford trench contents

TRI-CITIES - Work is nearly complete to help identify the type and amount of radioactive and hazardous materials at the 618-10 Burial Ground, one of the most hazardous sites on the Hanford nuclear reservation.

Washington Closure Hanford workers have dug test pits in burial trenches containing laboratory waste, drums — including one with depleted uranium shavings — and other material at the site about six miles north of Richland and just off Hanford’s main highway.

The discoveries will help determine exactly what was discarded in the trenches when the six-acre burial site was used between 1954-63.

That information will help guide a plan for cleanup that’s expected to start in spring 2011, Washington Closure and Department of Energy officials said Thursday.

The cleanup project is one of the most challenging to date at Hanford because records of what was dumped in the 12 trenches are incomplete, said John Darby, Washington Closure project manager.

And the information that is available “indicates we’ll encounter some of the most hazardous waste on the site,” said Mark French, DOE’s federal project director for the River Corridor Closure project.

Low- and high-activity radioactive and hazardous waste at the site came from 300 Area laboratories and fuel development facilities.

Also at the 618-10 Burial Ground are 94 vertical pipe units, which are five bottomless 55-gallon drums welded together end-to-end and then buried vertically so waste could be dropped into them. High-activity radioactive waste typically was disposed of in the pipes.

Already, workers have uncovered test tubes, bottles, boxes, a shipping cask with unknown contents and other laboratory equipment. They also have found several 55-gallon drums, which may contain radioactive liquid waste nested inside a pipe that’s surrounded by concrete.

They also unearthed a deteriorating 30-gallon drum containing depleted uranium chips in oil, which was used to help prevent the possibility that the chips would ignite if exposed to oxygen.

Based on where workers found the drum, officials now have revised their estimate of the number of drums — which could contain uranium shavings, uranium oxide or other radioactive material — they could find from 700 to 2,000, Darby said.