Date/Time
Date(s) - 02/09/2023
1:55 pm - 2:55 pm
Location
Rhines 125
Categories
Carolyn Pearce, Ph.D.
Chemist, IDREAM Director
Pacific Northwest National Laboratory
Dr. Carolyn Pearce joined Pacific Northwest National Laboratory (PNNL) in 2016 and leads research programs for the US DOE Office of Science, Office of River Protection, Environmental Management. She is the director of the PNNL-led Interfacial Dynamics in Radioactive Environments and Materials (IDREAM) Energy Frontier Research Center (EFRC) and is a team lead in the Environmental Subsurface Science Group.
She works on the characterization of solutions and 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.
Dr. Pearce obtained her B.Sc. and Ph.D. from the University of Leeds, UK, and is an Honorary Professor in the Department of Earth and Environmental Sciences, University of Manchester, UK, and an Adjunct Professor in the Department of Crop and Soil Sciences, Washington State University.
Abstract
The Hanford site in Washington state, which produced plutonium for the US weapons program, is the most contaminated nuclear site in the nation and is its largest environmental clean-up activity.
During weapons production, 56 million gallons of liquid waste, with 170 million Curies of radioactivity and 240,000 tons of complex chemicals, was generated. The waste is stored in 177 single-shell tanks (SSTs) or double-shell tanks (DSTs). Sixty-seven of Hanford’s SSTs are suspected of having released up to 1 million gallons of waste to the subsurface. Although all pumpable liquid has been transferred to DSTs as a form of interim stabilization, several million gallons of interstitial, drainable liquid remain in the 149 SSTs. Several methods have been used to compile an inventory of waste lost to the subsurface migrating through the vadose zone towards groundwater.
The Hanford site will be presented as a case study of an anthropogenic radioactively contaminated land site. The background to the contaminated land will include the plutonium production mission, waste sites and leaks, and remediation strategies. For key radionuclides, the influence of subsurface mineralogy and microbiology on fate and transport will be discussed.