Hydrothermal decomposition of actinide(IV) oxalates: a new aqueous route towards reactive actinide oxide nanocrystals

Hydrothermal decomposition of actinide (IV) oxalates (An= Th, U, Pu) at temperatures between 95 and 250°C leads to the production of highly crystalline, actinide oxides nanocrystals (NC's). This aqueous process proved to be quantitative, reproducible and fast (depending on temperature). The NC’s obtained were characterised by X-ray diffraction and TEM showing their size is smaller than 15 nm. Attempts to extend this general approach towards transition metal or lanthanide oxalates failed in the 95-250 oC temperature range. The hydrothermal decomposition of actinide oxalates is therefore a clean, flexible and powerful approach towards NC’s of AnO2 with possible scale-up potential.JRC.G.I.3-Nuclear Fuel Safet