DOE Working on Life Extension of Hazardous Waste Tanks
The Department of Energy’s Office of Environmental Management and its contractor Washington River Protection Solutions (WRPS) demonstrated the use of cold spray technology as a means of refurbishing double-shell waste tanks at the Hanford Site. The tanks store liquid radioactive and chemical waste that was created during plutonium production era within the Manhattan Project.
The large underground tanks consist of a main tank inside a secondary liner surrounded by a reinforced concrete shell.
Treated waste stored in the tanks will be fed to Hanford’s low-activity waste vitrification facility at the Waste Treatment and Immobilization Plant for immobilization in glass. This process is slow, so there is a need to move waste due to ageing of tanks or to reinforce available tanks.
Cold spray is a solid-state material deposition process, where micron-sized feedstock powder particles are propelled by pressurized high velocity gas toward a substrate, forming a coating on impact.
Mock-up demonstrations were performed at Hanford’s Cols Test Facility to show that robotic equipment can be lowered into the space between the first and second shells of a double-shell tank to navigate the space. This most recent demonstration validated the system’s ability to navigate the tank wall.
In future, such a technology can be added to the instruments of Phoenix project to replace old thermal power plants with small modular reactors. Many thermal power plants have incineration facilities not only for coal and peat, but also gas and fuel oil. Before being fed to the facility, fuel oil is stored in multi-cube tanks that may be needed for tank fleet of future reactors. Due to rather a long service life, walls of the tanks became thinner and could lose their applicability. Hanford spray technology can significantly reduce the cost of tank restoration or postpone the construction of new ones.