RICHLAND, Wash. – EM’s Office of River Protection (ORP) continues to make substantial progress in its mission to safely and efficiently reduce risk at the Hanford Site by managing and retrieving millions of gallons of radioactive waste stored in massive underground tanks.
ORP tank operations contractor Washington River Protection Solutions (WRPS) recently began retrieving waste from single-shell Tank AX-104 and transferring the waste to a newer, more robust double-shell tank for safe storage. To date, EM has completed waste retrieval from 17 of Hanford’s single-shell tanks.
“Moving waste into the double-shell tank system helps reduce risk to the environment and allows for safe storage of the waste until it can be treated,” said Brian Harkins, ORP deputy assistant manager for tank farms.
Tank AX-104, one of four tanks that make up Hanford’s AX Farm, contains more than 5,000 gallons of highly radioactive sludge-like material on the tank floor and 2,000 gallons of the material on the tank walls. The retrieval strategy for the 1-million-gallon-capacity tank involves mobilizing the waste by using pressurized water directed through robotic sluicing equipment, then pumping the slurry to a double-shell tank for safe storage.
WRPS set the stage for retrieval of Tank AX-104 by carefully removing highly contaminated legacy equipment from the tank — such as pumps and thermocouples — and installing waste retrieval infrastructure in AX Farm. A thermocouple is a device that measures the temperature of waste.
The infrastructure included a new ventilation system to filter emissions and a state-of-the-art facility that houses the water supply systems used to support retrieval activities. The in-tank waste retrieval system consists of three cannon-like sluicers, a central pump, and six camera and lighting systems. Sluicers are used to mobilize the waste and move it to a central pump.
Established safety controls will be in place throughout the entire retrieval process. ORP and WRPS also used lessons learned from previous retrieval projects to help keep workers safe.
“We have a highly skilled, innovative team with a strong track record of meeting the unique challenges that come with tank waste retrieval. For all retrieval projects, we develop a thorough project plan, choose the right tools for the job, and complete work safely,” said Doug Greenwell, WRPS retrievals manager.