Fabrication and characterization of (U, Am)O2−x transmutation targets

A novel dust-free route for the preparation of (U, Am)O2−x targets has been demonstrated using a combined sol–gel and single- or double Am-infiltration process at the Minor Actinide Laboratory (MALAB) of the Institute for Transuranium Elements (ITU). Samples with 10 and 20 mol% of Am were prepared. For both Am concentrations, a single cubic phase material with a fluorite structure was observed by X-ray diffraction. X-ray absorption spectroscopy was carried out to characterize the chemical state of the metal atoms and their local crystallographic environment. The U(IV) and Am(III) valence states are predominant and the O/Am ratio is ∼1.6 for both Am contents. For the 20 mol% Am, EXAFS reveals an expansion of the Am–O (2.43 Å) bond length beyond the metal–oxygen bond length in both AmO2 (2.31 Å) and UO2 (2.35 Å).