Abstract
Intermixing and clustering between U/Nd, Oxygen and vacancies were studied by both synchrotron and laboratory X-ray diffraction in U1-yNdyO2-x alloys. It was found that increased holding time at the high experimental temperature during initial alloy preparation results in a lower disorder in Nd distribution in the alloy. Adjustment of oxygen concentration in U1-yNdyO2-x alloys with different Nd concentration is accompanied by vacancy formation at the Oxygen sublattice. Lattice parameters in the U1-yNdyO2-x alloys deviate from the Vegard’s law for high concentration of Nd. Lattice parameters and d-spacing consistently decrease with Oxygen concentration at all Nd concentrations indicating the vacancies formation during oxygen adjustment at high temperatures. Change in vacancy concentration after oxygen adjustment is estimated relative to Nd concentration and oxygen stoichiometry.