As part of its mission to safely complete five decades of environmental cleanup of legacy waste, the U.S. Department of Energy (DOE) is undertaking an unprecedented engineering and technically challenging project to construct a first-of-a-kind waste treatment complex. It will immobilize some 56 million gallons (nearly 212 million liters) of liquid and semisolid nuclear and chemical waste, a legacy of World War II and Cold War nuclear weapons production.
At the DOE's Hanford Site, 177 aging underground tanks store the waste. Some of the tanks date to World War II, when the site was established as part of the Manhattan Project, and 67 have leaked an estimated 1 million gallons (3.8 million liters), threatening the Columbia River, surrounding communities, and residents downstream in the U.S. Pacific Northwest. The tanks are corroding and require constant maintenance.
A small portion of the Hanford Site's inventory of underground tanks, prior to burial. (Department of Energy historical photo)
In the 1980s and 1990s, Bechtel collaborated with the U.S. Department of Energy and industry to address a similar environmental problem at the Savannah River Site in South Carolina. The Defense Waste Processing Facility was the result, and continues to safely operate today.
Addressing the threat of leaking tank waste
In 2000, DOE selected Bechtel to engineer, build, and commission a multi-facility complex in Washington to address the threat of the leaking tank waste.
When operational, the Hanford Waste Treatment Plant (WTP—also known as the vitrification, or "vit," plant) will blend the radioactive waste with glass-forming materials such as silica and heat the mixture to 2,100 degrees Fahrenheit (1,149 Celsius).
The molten material will be poured into stainless steel canisters to cool and solidify in a glass, or vitrified, form. The waste will remain stable and impervious to the environment so that its radioactivity can safely dissipate over hundreds to thousands of years.
Workers test the Low Activity Waste Vitrification Facility container handling system.
Major construction of the first phase of facilities is complete. A multi-year startup, testing, and commissioning period is now underway.
The first team of chemists have begun their work inside the Vit Plant’s Analytical Laboratory, which in 2021 was declared Ready to Operate. The lab’s key function is to confirm that glass produced by the Low-Activity Waste vitrification facility meets regulatory requirements and standards.
During waste treatment operations, laboratory staff will analyze approximately 3,000 process samples annually to confirm high-quality glass product and good process controls. Analyses will also confirm the correct glass-former “recipe” needed to produce a consistent glass.
The laboratory team collaborated with Vit Plant engineers to analyze glass made from a variety of low-activity wastes simulant and glass-forming materials. This same analytical method will verify the glass vitrified in the Low-Activity Waste Facility meets DOE standards.