The DOE EPSCoR Implementation project is divided into four major tasks as well as the development of an imaging laboratory to monitor the transport of radionuclides through 2D and 3D engineered waste forms and natural soils as a function of time. These experimental tasks and the personnel involved are:
- Imaging Facility Design and Implementation: Imaging Tools to Support Radionuclide Transport Studies DeVol (Lead), Clemson; Darnault, Clemson; El-Batanouny, USC; Martinez, Clemson; Moysey, Clemson; Ziehl, USC.
- Task A: Origins of Radionuclide Source Terms in Legacy and Advanced Waste Forms (Knight (lead), USC; Brinkman, Clemson; Flora, USC; Matta, USC; Serkiz, Clemson; Shuller-Nickles, Clemson; Zeihl, USC)
- Task B: Biogeochemical Behavior of Radionuclides in Natural Systems: Mineral, Plant, and Microbial Interactions (Powell, Clemson; Chang, SCSU; Danjaji, SCSU; Darnault, Clemson; Finneran, Clemson; Serkiz, Clemson; Tharayil, Clemson)
- Task C: Intermediate Scale Characterization of Radionuclide Mobility in Natural and Engineered Systems (Moysey (Lead), Clemson; Dardault, Clemson; DeVol, Clemson; El-Batanouny, USC; Matta, USC; Murdoch, Clemson; Powell, Clemson; Ziehl, USC)
- Task D: Computational Tools to Characterize Waste Form Performance and Radionuclide SubsurfaceTransport (Murdoch (Lead), Clemson; Battiato, Clemson; Caicedo, USC; Falta, Clemson; Flores, USC; Knight, USC; Molz, Clemson; Moysey, Clemson, Powell, Clemson, Shuller-Nickles, Clemson; Zheng, SCSU).
Each experimental task was designed based on four focus areas which are intended to guide the scientific pursuit of the task. These focus areas provide a framework to monitor how each of the systems being examined changes over time. Specifically these examine how the chemical speciation and mobility of the radionuclides is influenced with respect to the spatial and temporal distribution of reactants and the physical state of the system. These focus areas are listed below along with some brief descriptive text.
- Understanding spatial interactions and feedbacks: At all scales, spatial organization of solid assemblages controls the chemical environment through the availability of reactants (i.e., water, oxygen, and nutrients). This control of the chemical availability locally determines the mobility of radionuclides in porous media and ultimately determines macroscopic transport behavior.
- Understanding temporal variations and instability: At all scales, mobility of radionuclides is enhanced by episodic transitions in the spatial organization of flow systems (including water, oxygen, and nutrient supplies) resulting in temporary shifts in (biogeo)chemical environments. The mobility of radionuclides in soils is fundamentally controlled by the geochemical, microbial, and rhizomal environment of the subsurface.
- Influence of Amendments and Additions: Amendments to any system such as carbon nanoreinforcements of cements, molecular doping of ceramic waste forms, microbial or plant mediated introduction of complexing agents to pore waters, or availability of chemical reactants can influence radionuclide chemical speciation and mobility in natural or engineered systems.
- Process scaling (and relationship to modeling): As the relative heterogeneity of the system increases (i.e. as smaller scales are observed even in relatively homogenous systems) radionuclide behavior can only be described using non-equilibrium processes. Conversely, increasing in the relative size of the system will increase the apparent ability of equilibrium expressions to describe a system.
NEESRWM Director: Dr. Tim DeVol
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