Synthesis and characterization of nanocrystalline U1-xPuxO2(+y) mixed oxides

We report here the first synthesis of mixed oxide U1-xPuxO2(þy) nanoparticles. The obtained nanopowders were characterized by X-ray diffraction, thermal ionization mass spectrometry, transmission electron microscopy, Raman spectroscopy, and U M4 edge high-energy-resolution X-ray absorption near edge structure (HR-XANES). The HR-XANES spectra give evidence for the partial oxidation of UIV to UV. This novel route toward the formation of actinide-actinide solid solution opens research opportunities that are not accessible using bulk materials. We give details on the X-ray diffraction study on plutonium oxalate hexahydrate, as a reagent for the synthesis of such nanoparticles.JRC.G.I.3-Nuclear Fuel Safet