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Carolyn Pearce, PhD
Chemist; IDREAM Director
Carolyn Pearce, PhD
Chemist; IDREAM Director
Biography
Fifty-six million gallons of radioactive waste are stored in underground tanks at the Hanford Site in Washington. These wastes, byproducts of decades of plutonium production, are a complicated mix of salts and sludges that have been exposed to ionizing radiation for decades.
The Department of Energy in 2016 created a center to better understand the chemistry of this radioactive waste. It’s called IDREAM—Interfacial Dynamics in Radioactive Environments and Materials—based at Pacific Northwest National Laboratory (PNNL) and led by Carolyn Pearce.
“Our overarching goal is to develop a fundamental understanding of the behavior of these concentrated electrolytes,” said Pearce, appointed as IDREAM director in 2021 after joining the Environmental Subsurface Science group. “The waste in the tanks has very little water. It's an extreme environment, very alkaline, and obviously contained in a radiation field.”
“We want to better understand the behavior of ions in these concentrated extreme environments and then be able to predict how those ions will behave during processing, and in any potential waste form for disposal or containment.”
In 2020, IDREAM was awarded funding, worth $14 million over four years, from the Department of Energy Office of Science for the second phase of research.
Pearce, with a doctorate degree in color and polymer chemistry, works on the characterization of minerals relevant to radioactive waste storage and processing in order to determine reaction mechanisms and kinetics that affect radionuclide stability in waste forms and subsurface environments.
What might provide a clue for long-term Hanford waste storage? Pearce has looked to an ancient civilization for a clue. She and colleagues have closely examined glass from Broborg, a vitrified 1,500-year-old hillfort in Sweden. The research shows that glass is resistant to wear, making it a suitable candidate for encapsulating waste, such as radioactive material.
“It’s the right sort of chemistry for us to look at as an analog for the low-activity waste that they'll dispose of out on the Hanford Site,” Pearce said.
In addition to IDREAM, Pearce is the Signatures team leader in PNNL's Earth Systems Science Division's Environmental Subsurface Science group. She is a visiting academic in the Department of Crop and Soil Sciences at Washington State University, and in the School of Earth and Environmental Sciences at the University of Manchester, United Kingdom.