Workers at the US Department of Energy (DOE) Office of Environmental Management (EM) Hanford site recently transferred more than 430,000 gallons of radioactive and chemical waste from Single-Shell Tank (SST) A-101 to a newer double-shell tank (DST) for continued safe storage. Crews from site contractor Hanford Tank Waste Operations & Closure (H2C) started tackling the work in summer 2024, using remote-controlled equipment and pressurised water to break up waste.
“This work addresses some of the most challenging and hazardous waste at Hanford,” said Katie Wong, programme manager with the Hanford Field Office Tank Farms Programs Division. “Every tank we retrieve waste from not only reduces potential exposure but also shows our commitment to protecting people and the environment.”
Hanford produced plutonium for US nuclear weapons from 1944 to 1989 and is now undergoing clean-up. The site is home to 177 underground waste storage tanks – a legacy of nuclear weapons development and nuclear energy research during World War II and Cold War. These include 149 SSTs and 28 DSTs, ranging from 55,000 to 1.265m gallons in capacity. The tanks are organised into 18 different groups, called farms.
The first SSTs were put into service in 1944 and were designed to be in use for about 20 years. They were built with a carbon-steel liner surrounded by a layer of thick, steel-reinforced concrete and buried 10 feet below the ground. In the 1950s some of the SSTs began leaking waste into the surrounding soil. The waste in the tanks has now been stabilised by removing all free liquid from it, minimising the chance of further leakage.
Construction of DSTs began in 1968. Each DST has a carbon-steel inner tank with a separate steel liner surrounding it to prevent leaks to the environment. The tank liners are separated by an air space of about 30 inches, equipped with a leak-detection system.
The waste will eventually be sent to the nearby Waste Treatment and Immobilisation Plant to be vitrified into glass for safe disposal. This was the 22nd single-shell tank to undergo waste retrieval. Workers will now move to Tank A-102.
“We are committed to making sure these operations are conducted safely and effectively, reflecting our dedication to protecting the environment and the community,” said Dave Saueressig, H2C’s retrievals manager.
