By Annette Cary, Tri-City Herald staff writer
Hanford workers have finished removing 11 obsolete transfer lines contaminated with high-level radioactive waste in the Hanford tank farms.The flexible lines were used to transfer waste from leak-prone single-shell tanks into sturdier double-shell tanks, but the lines were past their design life. Some were buried in shallow trenches and others were above ground and covered with shielding to protect workers from radiation.
"Removal of these lines allows workers to focus on retrieving the sludge-like waste remaining in the single-shell tanks without these obstacles and interferences," Stacy Charboneau, DOE assistant manager for the tank farms, said in a statement. It also reduces risk to workers and the environment.
Washington River Protection Solutions committed to the Department of Energy and the Washington State Department of Ecology, a Hanford regulator, to remove the six lines in the U Tank Farm when the new tank farm contractor began work a year ago.
Because the work was done for less money than budgeted and some additional money was appropriated by Congress, five more lines in the C Tank farms also were removed. The total cost was $1.8 million.
The U Tank Farm lines were last used to remove pumpable liquids from underground single-shell tanks before that work was completed for all Hanford tanks in 2004. The C Tank Farm lines were used more recently as work continued to remove solid waste from the tanks.
The C Tank Farm lines had to be disconnected from the tanks and then flushed with water to remove contaminants. The lines include a hose inside a hose so that if the inner hose leaked, contamination would be trapped in the outer hose.
Nine of the lines have been packed in waste containers and shipped to the Environmental Restoration Disposal Facility in central Hanford. However, two lines still were too contaminated to be sent to that landfill. They were sent to Perma-Fix Northwest Richland to be cut into smaller pieces and then returned for disposal at Hanford's solid waste burial ground.
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