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John Vienna, PhD
Materials Scientist
John Vienna, PhD
Materials Scientist
Biography
Materials scientist John Vienna is putting one of the world’s oldest manmade materials—glass—to work solving one of humankind’s newest materials problems—nuclear waste management. “We get extra points for how pretty the glass is,” jokes Vienna. But he’s very serious about the composition of the glass, how well it incorporates radioactive wastes, and how well it will hold up over millions of years.
He and his colleagues at PNNL design waste forms, like borosilicate glass, and then study and model their long-term performance or ability to keep long-lived radionuclides out of the environment.
The process, called vitrification, converts the radioactive waste into glass by mixing it with silicate materials and then melting them together at a temperature of 2,100 degrees Fahrenheit. The radioactive components are atomically bound to and become part of the glass. They can’t be released unless the glass dissolves, freeing them up.
His research has led to improved understanding of the long-term corrosion of nuclear waste glasses in disposal environments. Based on this research, the glass is designed to last for up to a million years so most of the radioactivity decays before it can leach out into the environment.
Vienna’s materials-by-design approaches for real-time waste glass optimizations and qualification have helped enable the Hanford Tank Waste Treatment and Immobilization Plant design. He has also designed glass compositions for immobilization of wastes at the Defense Waste Processing Facility, the Fukushima Diitchi 1F site, and various others.