TRI-CITIES, Wash. — 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 at the site 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.
Officials hope to find about 20 drums in various locations, presumably containing a representative sample of what can be expected when full-scale remediation begins next year.
“From the records, we can’t tell exactly how many,” he said.
Records that do exist indicate the 618-10 Burial Ground likely holds laboratory equipment and hoods, electrical equipment, metallurgical samples, filters, aluminum cuttings, bottles, boxes and laboratory clothing and gloves.
John Ludowise, Washington Closure resident engineer, since last year also has been researching what kind of work was being done in the laboratories where the waste originated during those years to determine what else might be in the burial ground.
“It’s been a laborious process,” Ludowise said.
So far, however, there has been nothing unusual found, Darby said.
“The surprise is (the trenches) are not chock full of waste to the top as we’ve found in other burial grounds,” he said.
About $66 million in American Recovery and Reinvestment Act funding is helping jump-start the cleanup project, which is expected to take several years.
Starting the work now is important because the site must be cleaned up by 2018 to meet a Tri-Party agreement milestone, officials said.
Total cost of cleanup of the 618-10 Burial Ground and a similar site nearby — the 618-11 Burial Ground — could be $150 million to $250 million, “but that will depend on what we find, and it (cleanup) could go faster than we planned. We don’t know yet,” French said.
Infrastructure will have to be installed at the site before work can begin, including power lines. Wells also will have to be dug to supply water to keep down dust.
Once cleanup begins, some of the recovered solid waste will be disposed of at Hanford’s central cleanup landfill, the Environmental Restoration Disposal Facility.
Drums containing oil and depleted uranium chips will be shipped to a treatment facility where the oil — which could contain heavy metals and PCBs — will be drained and incinerated, Darby said. Uranium shavings will be stabilized and returned for disposal at ERDF.
The burial ground is one of 396 waste sites that Washington Closure is cleaning up in a 220-square-mile area of the Hanford site adjoining the Columbia River.
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