The Department of Energy’s Office of Environmental Management (EM) said in an April 18 release that workers have so far removed almost 150,000 gallons, or about 35 percent, of the radioactive and chemical waste from Tank AX-101 at the department’s Hanford Site near Richland, Wash. Retrieval from this tank began in January.
Workers with EM contractor Washington River Protection Solutions are transferring the single-shell tank’s 426,000 gallons of waste, primarily solid saltcake and some sludges, to newer double-shell tanks for safe storage until it can be treated.
“Removing the waste from the single-shell tanks and upgrading the aging infrastructure in the tank farms is a top priority for the Department of Energy,” said Delmar Noyes, assistant manager for the EM Office of River Protection’s tank farms project. “It is a necessary step to protect the community and the Columbia River and to advance our mission to reduce risk on the site.”
Last of the AX Farm: Tank AX-101 is the last of four tanks in Hanford’s AX Farm to be retrieved, and when completed, Tank AX-101 will be the 21st of Hanford’s 149 single-shell tanks to be retrieved. AX Farm will be the second tank farm at Hanford where retrieval operations have been completed. Retrieval of the site’s C Farm tanks was completed five years ago.
Sluicing—a procedure using high-pressure water spray—is used to break up the waste so it can be pumped out of the tank and transferred to a double-shell tank. Workers operate the equipment remotely from a nearby control trailer.
According to the Washington Department of Ecology, retrieval of the AX Farm tanks was made more difficult by cooling air circulators within the tanks that created obstructions for the retrieval equipment. In addition, the radiation levels in the AX tanks were higher than those in the C Farm tanks.
Hanford’s single-shell tanks were first put into service in 1944 and were designed to be in use for about 20 years. Hanford has 28 double-shell tanks. The underground tanks (single- and double-shell) are organized into 18 different tank farms and hold waste generated during the production of weapons plutonium at the site.
Next up: EM said that crews are currently preparing other tanks for retrieving and receiving waste. Workers were recently trained on new tools to make it safer and more efficient to remove a contaminated pump from the double-shell Tank AY-101. The training readies the workers as they prepare the tank to receive waste in the future.
Workers continue to set up the six tanks in the adjacent A Farm for waste retrieval operations by removing outdated equipment and installing new retrieval systems and infrastructure. To retrieve waste from one of the tanks, A-106, workers will drill a hole through the top of the underground tank to install retrieval equipment.
Workers at Hanford’s Cold Test Facility are building a mock-up to test the cutting system, which is designed to help protect workers from radiological exposure when they drill into the tank.