Fabrication and Characterization of (U,Pu)O2 Ceramic Fuel Pellets from Powders after Thermochemical Denitration of Nitric Acid Solutions

Thermochemical denitration of nitric acid solutions of U and Pu to obtain mixed uranium–plutonium formates was performed. It was followed by the reduction of the mixture in Ar–H2 (5 vol %) to obtain a powder of mixed U–Pu dioxide. The products obtained were studied and characterized by X-ray diffraction, X-ray fluorescence analysis, and Raman spectroscopy. The analysis of the powder revealed the formation of a (U,Pu)O2 solid solution containing 5 wt % Pu and of UO2. After the powder treatment by vortex mixing, high-density pellets of homogeneous structure were fabricated.