RICHLAND, Wash. — In a groundbreaking achievement decades in the making, the Hanford Site has commenced the process of immobilizing low-activity radioactive waste by converting it into glass, a technique known as vitrification. This significant milestone marks the successful start-up of Hanford’s Waste Treatment and Immobilization Plant, commonly referred to as the “Vit Plant.” The facility will transform millions of gallons of waste generated by plutonium production during the Manhattan Project and the Cold War into glass for safe storage over thousands of years. This achievement reflects nearly 60 years of scientific contributions by the Department of Energy’s Pacific Northwest National Laboratory (PNNL).
“PNNL is proud to have played a pivotal role in advancing modern vitrification technology,” said Deb Gracio, PNNL director. “This milestone underscores the importance of innovation, collaboration, and scientific excellence in solving some of the world’s most pressing problems.”
The Science Behind Vitrification
Since the 1960s, PNNL researchers, including chemical engineers, computational scientists, and materials scientists, have been at the forefront of advancing vitrification science. Their innovations have not only led to this historic achievement but have also informed vitrification operations globally. A key technology developed by PNNL is the liquid-fed ceramic melter, a tool widely used in vitrification processes worldwide. Inside these melters, temperatures can reach 2,100°F, allowing waste to be mixed with glass-forming chemicals and transformed into glass.
Each of the Hanford Site’s 177 one-million-gallon-capacity tanks contains chemically unique waste. The composition of these wastes dictates the behavior of the waste and the glass-forming chemicals needed. The challenge has been to design a glass that incorporates and immobilizes as much waste as possible while being durable and manageable within the plant’s infrastructure.
Innovative Approaches and Global Impact
John Vienna, a PNNL materials scientist, highlighted the challenge of vitrifying the Hanford Site’s chemically complex waste. “The Hanford Site’s waste is not only the most complex waste in the world but also the largest quantity ever targeted for vitrification,” he noted. To address this, Vienna and his colleagues developed a computational approach to glass design, using models trained on historical testing results to generate glass “recipes” that are processable, economical, and long-lasting.
This computational approach has saved years of effort and millions of dollars, as demonstrated at the DOE’s Savannah River Site in South Carolina. By comparison, a similar traditional approach at New York’s West Valley Demonstration Project in the late 1990s took roughly a decade. At Hanford, the process now takes less than 120 minutes, with PNNL’s glass algorithm app becoming increasingly efficient.
Continuing the Legacy
PNNL has been integral to the design of the melters and other key equipment at the Vit Plant. Innovations such as the submerged bed scrubber and the air displacement slurry pump were initiated at PNNL. Will Eaton, a melter specialist, has led efforts to improve melter materials and optimize processing, enabling each melter to produce up to 15 metric tons of glass per day at full capacity.
Chris Musick, general manager of the Bechtel-led Waste Treatment Completion Company LLC, praised PNNL’s contributions. “PNNL has been an integral part of the Hanford Waste Treatment and Immobilization Plant,” he said. “We look forward to growing our partnership with PNNL as we move forward with treating tank waste.”
Looking to the Future
Today, PNNL scientists continue to support the Hanford Vit Plant by analyzing pretreated and vitrified waste and providing rapid solutions during the facility’s start-up. Materials scientist José Marcial, who began his scientific career with a vitrification-focused internship at PNNL, expressed excitement about the project’s progress. “This shows that this isn’t just an academic exercise. It’s all of our effort being put to real use to benefit the country and our community,” Marcial said.
As vitrification at Hanford progresses, the work is far from over. PNNL researchers are focused on improving efficiency, refining glass algorithm performance, and addressing operational challenges. They are also contributing to broader cleanup missions, including grout waste form development and environmental remediation.
Marcial emphasized the importance of nurturing future scientists. “I think it’s important to always bring up the next generation of scientists so they, too, can help solve challenges for the benefit of the country,” he concluded.
