CH2M HILL's Waste Retrieval
Single Shell Tanks
Over the last seven years, CH2M HILL has made safe and steady progress in Hanford tank cleanup. Pumpable liquids have been removed from all of the 149 single-shell tanks to reduce the risk of future leaks. The last liquid waste was transferred to safer double-shell storage in 2004. Approximately 2.9 million gallons of retrievable liquid waste was transferred to safer double-shell storage between 1998 and 2004.
What Happens to the Remaining Waste?
The solid material remaining in the single-shell tanks includes salt cake and sludges. this waste is now being retrieved and, like the liquids, it is being transferred to double-shell tanks where it will be safely stored until it is prepared for final disposal.
An example of CH2M HILL's waste retrieval efforts is single-shell tank C-106, one of Hanford's oldest radioactive waste storage tanks, was the first of Hanford's singe-shell tanks to be emptied. The tank, located in C-farm, represented one of Hanford's highest priority cleanup challenges throughout the 1990s. Removal of the tank's solid waste was exceedingly complex.
High pressure water jets were used to dissolved the waste so it could be pumped, but pumping was interrupted at ties due to the density of the material. At times, low concentrations of oxalic acid had to be added to dissolve the waste to the point that it could be removed. In spite of these and other challenges, the tank was emptied to the point that weld seams are now visible along the tank floor.
Cold Test Facility
The Hanford Cold Test Facility (CTF) is our test model for tank waste retrieval technologies. Hanford's underground radioactive and chemical waste storage tanks present unique hazards to our workforce. To overcome these hazards we use the CTF to test hardware and train personnel who will operate the technologies. It is a non-radioactive environment that simulates tank waste conditions to determine whether a particular piece of hardware will function as intended without compromising the safety of our workers.
Adjoining the CTF is the Joint Briefing Center where the Office of River Protection and CH2M HILL manager can provide detailed information about waste management and retrieval operations to Hanford Site visitors. Technological advances and innovations such as the CTF are leading the way in nuclear operations.
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Cold Test Facility Overview (1.40MB) |
Hose-in-hose Transfer Lines
Installation work is nearly complete on the Hose-In-Hose Transfer line that will carry waste from single-shell tank C-108 to double shell tank AN-106. Waste retrieval from C-108 is a 530,000 gallon tank that currently holds approximately 66,000 gallons of sludge and other waste materials.
Waste will be removed from C-108 using the modified sluicing process. This technique consists of nozzles that spray the waste with water under approximately 100 pounds of pressure at a flow rate of about 100 gallons per minute. Not only does the high-power spray dissolve, break up and mobilize the waste, it also drives it to a central pump for removal.
When retrieval is a complex project that required a well thought out plan of action - including an intricate sequencing to get the job done safety. We have a highly trained and experienced work force that will get the job done right.