The US Department of Energy (DOE) team at the Hanford Site in Washington state has finished removing radioactive waste from the 23rd large underground storage tank.

From 1944 to 1989, Hanford produced 74 tons of plutonium for the country’s nuclear weapons program. To store the radioactive and chemical byproducts, the site built thick, reinforced concrete tanks lined inside with steel and buried under several feet of soil to shield workers from radiation. The tanks held up to a million gallons each, and when production stopped at the end of the Cold War, 56 million gallons of waste was in 177 of the large tanks.

Hanford Tank Waste Operations and Closure (H2C) workers have now transferred about 41,000 gallons of decades-old solid waste from single-shell Tank A-102 in the site’s East Area to a double-shell tank for continued safe storage. Waste removed from the 23 tanks to date totals about 3.4m gallons.

The Department and its contractors have completed retrieval operations in two of the Site’s tank farms. Tank Farm A is the third to have waste moved out of the older tanks with a single steel liner into newer tanks that have a second liner for added leak protection.

“Safely retrieving waste from ageing tanks is one of Hanford’s highest priorities,” said Hanford Field Office Assistant Manager for Tank Waste Operations, Mat Irwin. “This retrieval reflects steady progress, disciplined execution and our continued commitment to protecting human health and the environment.”

Phil Breidenbach, H2C’s Chief Operating Officer noted: “The Hanford workforce is highly skilled and well-trained to meet the unique challenges that come with tank waste retrieval,” said. “Their success stems from their ownership of the mission and their commitment to reducing risk.”

Workers already are making progress removing waste from the Site’s 24th single-shell tank, A-106. Retrieval operations on that tank should be completed later this summer.