INNOVATIVE TECHNOLOGY DEMONSTRATION UNDERWAY
Salt Mantis Deployed in Hanford Tank

Richland, WA - CH2M HILL Hanford Group and the Department of Energy, Office of River Protection announced today that they have launched an innovative demonstration project inside one of Hanford’s single-shell radioactive waste storage tanks. This new project will test the viability of a device known as the “Salt Mantis” to break up stubborn tank waste that won’t yield to other technologies.

CH2M HILL is the prime contractor to the Department of Energy’s Office of River Protection, and is responsible for the safe management of Hanford’s underground radioactive tank waste until it is prepared for disposal.

The Salt Mantis uses a sophisticated nozzle system on a track device that shoots up to six gallons of water per minute at a pressure of up to 35,000 pounds per square inch. The device is manufactured by TMR Associates LLC, Lakewood, Colorado. By comparison, a fire hose can shoot a stream of water at 125 pounds pressure at a flow rate of 150 to 250 gallons per minute.

The remotely-operated Salt Mantis was recently inserted inside single-shell tank S-112 located near the center of the Hanford Site north of Richland, Washington. The installation was not an easy task because the device had to fit through a pipe that is just twelve inches in diameter in order to be placed in the tank. To overcome the stringent space limitations, the device is designed to fold up similar to a pair of scissors. Once inserted into the tank, the Salt Mantis opens up and begins its work. Approximately 30,000 gallons of hardened waste remains on the bottom of the tank remain, after more than 584,000 gallons of liquids and sludges were removed from S-112 using a technique known as “salt cake dissolution.”

“This demonstration will tell us if the Salt Mantis will be effective in mobilizing the waste so it can be pumped out,” said Rick Raymond of S-Farm Retrieval Operations.

Each tank contains various constituents, and waste forms vary from one tank to another. These forms can include liquids, hard salt-like material and sludges. Retrieval strategies include a number of technologies to best attack the waste specific to the demands of the waste and tank. If the Salt Mantis proves effective, it will become one of several different tools that are utilized to retrieve waste from single-shell tanks. Other tools and techniques being used include acid dissolution, modified sluicing, the mobile retrieval system and vacuum retrieval.

“Since being installed, the Salt Mantis performance has exceeded our most optimistic projections and we can already see the bottom of the tank in several places,” Raymond said.

Before being deployed inside tank S-112, the Salt Mantis was tested at the Cold Test Facility north of Richland to train the operating crews and learn as much as possible before it is deployed in an actual Hanford tank. This life-size tank allows CH2M HILL to test technologies, train operating crews and demonstrate operating procedures in an environment where no contamination is present. The Cold Test Facility puts the job to the test, while protecting the workforce.