Waste Storage

For more than 40 years, facilities at the Hanford Site produced plutonium critical to the nation’s defense during World War II and throughout the Cold War.

This effort resulted in the production of 56 million gallons of radioactive and chemical wastes, which are currently stored in 158 underground tanks. The tanks range in capacity from 55,000 gallons to over 1 million gallons. Hanford is home to 177 underground waste storage tanks: 149 single-shell tanks and 28 double-shell tanks.

The tank waste is a complex and diverse combination of radioactive and chemical waste that takes the physical form of sludge, salts and liquids with varying combinations of chemical properties. Much of the waste is stored in 149 single-shell tanks, first constructed in the mid-1940s. The remainder is stored in 28 double-shell tanks of newer construction. The Department of Energy has minimized the risk of waste leaking from the single-shell tanks by removing pumpable liquids and transferring those liquids to the double-shell tanks.

No two tanks are the same:

  • No two tanks have the same waste contents
  • Moderate to high radioactivity
  • Highly caustic
  • Waste temperatures range from 60°F to 160°F
  • Most waste produces some hydrogen

The tanks are organized into 18 separate groups, called tank farms, situated on Hanford’s Central Plateau about 7 to 10 miles from the Columbia River.


Tank Farms

  • 149 tanks constructed 1943 – 1964
  • 55,000 – 1 million gallon capacity
  • Waste receipts ceased in 1980

SST Stewardship Project Execution Strategy (RPP-RPT-60443; Rev. 0)
The Single-Shell Tank (SST) Stewardship Project Execution Strategy Report explains the SST Stewardship Project (Project), which was a taskforce charged with evaluating options for reducing entries into SST Farms. The Project taskforce identified SST farm activities, then evaluated if the frequencies of the activities could be reduced to decrease the number of SST farm entries; thereby, lowering the potential risk to personnel performing the activities within the SST farms. Entry reduction opportunities were prioritized and a subset was further evaluated. This report recommends a list of tasks that could be reduced, and provides the corresponding reductions in SST farm entries and the potential cost savings. Read more.


Tank Farms

  • Composed of a primary tank with secondary containment (secondary tank)
  • 28 tanks constructed 1968 – 1986
  • 1 – 1.26 million gallon capacity
  • Retrieved SST waste and waste evaporator concentrate storage
  • 1 leaking, waste contained within annulus (space between inner and outer shell)