Characterization of sources from intermediate-scale field lysimeter studies of plutonium vadose zone transport
EMSL Project ID
48433
Abstract
The objectives of this work are to develop qualitative conceptual models and quantitative reactive transport models of plutonium migration in unsaturated zones (i.e. the vadose zone). The unique electron microprobe (EM) and transmission electron microscope (TEM) instruments in the radiological annex of EMSL will be used to determine the partitioning of plutonium to different mineral phases of soils from the Savannah River Site and characterize any Pu nanocolloids formed within the samples. A novel aspect of this work will be to utilize a unique field lysimeter system containing well characterized Pu sources that is open to natural rainfall and temperature fluctuations and is expected to last for at least 10 years. This project is focused on understanding Pu mobility and biogeochemistry within the soil environment. A self-consistent model of Pu fate and transport in the vadose zone will be developed that is constrained using high resolution analysis of the chemical and physical speciation of plutonium. This work will combine EM and TEM analysis done within the radiological annex at EMSL with the field data, laboratory studies, X-ray absorption near edge spectroscopy (XANES), Extended X-ray absorption fine structure spectroscopy (EXAFS), Fourier transform infrared spectroscopy (FTIR), and wet chemistry methods to develop a numerical description of plutonium transport that will include intermediate-scale coupled processes that are not commonly observed in laboratory and short-term flow experiments. It is anticipated that the data from these field studies will permit bench marking the existing models. These molecular level data are vital for the validation of the conceptual and quantitative sorption models developed as part of this larger project. The prediction of the Pu speciation and behavior in these field based samples using thermochemical sorption models will provide an unprecedented validation of the use of coupled biogeochemical models for prediction of plutonium transport in subsurface environments.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2014-07-01
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members