Np/Pu interaction with minerals (SS)

PI: Sam Shaw, University of Manchester.

The UK has high and intermediate level radioactive wastes containing large quantities of neptunium and plutonium. Currently, it is UK Government policy that these wastes should be contained within a Geological Disposal Facility (GDF). Within a GDF, sorption to minerals will be one of the key factors limiting the release of radionuclides to the biosphere. If the environmental behavior of transuranic elements, such as plutonium, are to be predicted a molecular scale understanding of their speciation is essential. High intensity X-rays generated by synchrotron facilities can be used to probe radionuclide speciation via X-ray Adsorption Spectroscopy (XAS). Currently, it is possible to perform XAS on low-level Np samples at the Diamond Light Source (DLS). However, the high radiotoxicity of Pu isotopes makes analysis at synchrotron facilities challenging as comprehensive safe systems of work and dedicated sample cells are required. Hence, there is currently no UK capability to analyse higher activity samples and those containing Pu isotopes. Therefore, the key aim of this project is to develop the procedures and sample cells that are required facilitate analysis at the DLS. Further, this new capability will be used to probe the behaviour of neptunium and plutonium in systems containing relevant minerals.