Hanford prepares to empty waste from single-shell tank

August 15, 2022, 7:00AMRadwaste Solutions
Hanford workers will soon begin retrieving about 373,000 gallons of waste from Tank AX-101, shown here in an image from an inspection video shot. (Photo: DOE)

Washington River Protection Solutions (WRPS) is preparing to retrieve waste from Tank AX-101 at the Department of Energy’s Hanford Site near Richland, Wash. WRPS is the tank operations contractor at Hanford.

The tank was one of 149 single-shell underground carbon steel units that was built to store radioactive and chemical waste from the production of weapons plutonium at the site. To reduce the risk of leaks, the DOE is transferring waste from Hanford’s older single-shell containers to newer double-shell tanks. A total of 28 double-shell tanks were built at Hanford between 1968 and 1986.

Tank AX-101 holds approximately 373,000 gallons of solid, salt-based waste called saltcake and sludgelike waste. The DOE noted on August 9 that it will be the last of the four one-million-gallon tanks in the AX Tank Farm and the 21st single-shell tank at Hanford to have its waste moved to double-shell tanks. Retrieval of waste from Tank AX-101 is expected to take between one and two years.

Uneven waste: According to the DOE, workers this summer installed the last of three extended-reach sluicers in the tank that will spray water on the waste to break it down so it can be pumped out.

Video images from cameras lowered into the tank before the last sluicer was installed showed the waste level was uneven, ranging from about 11 feet to nearly 14 feet deep in places. To avoid submerging the sluicer in about two feet of saltcake waste on the deeper side of the tank, potentially plugging its nozzles, workers modified a high-pressure washing system normally used to clean tank risers, nicknamed the “wolverine,” to make a hole in the saltcake waste for the sluicer nozzles to fit.

The sluicers, along with a slurry pump and other support equipment, are installed in several tank risers. During retrieval, workers will operate the equipment remotely from a nearby control trailer.

Quote: “We are excited to be nearing completion of a long preparation and installation process for this tank,” said Peggy Hamilton, single-shell tank retrieval and closure manager for WRPS. “The team will finish installing equipment and will thoroughly test it before starting to retrieve waste from the tank.”


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