Characterization of UO2-Gd2O3 nuclear fuel obtained by co-precipitation by Transmission Electron Microscopy

GANA WATKINS, IGNACIO; MENGHINI J.; PRADO, M. O.; TROIANI, HORACIO; SOLDATI,MORA

Bariloche

Workshop; IGORR 2014; 2014

IAEA

stract. In this work we characterize the chemical and structural homogeneity of a 4% weight Gd2O3 doped UO2 nuclear fuel obtained by co-precipitation techniques, using Transmission Electron Microscopy (TEM and STEM) coupled to an Energy Dispersive Spectroscopy (EDS) system. Particle morphology and crystallite sizes were determined using bright/dark field and high resolution (HR-TEM) images. We determined that the particles have an average crystallite size of 90±10 nm, with rounded forms. Convergent beam Energy Dispersive Spectroscopy (EDS) and Electron Diffraction (ED) were used to evaluate sample composition and homogeneity, even at the nanometer scale. We found that the apparent homogeneity observed with a Scanning Electron Microscope (SEM) at the micron scale, results in an inhomogeneous Gd distribution at the nanoscale. Moreover, from TEM-EDS analyses we determined the presence of Gadolinium in all the analyzed crystallites but with ±20% variation among the average concentration. Although burnable poison fuels are widely used for Nuclear Power Reactors, the methodology used in this work has demonstrated to be a helpful tool to understand (even at the nanometric level) their composition, structure and morphology, moreover it is suitable for its application in new Nuclear Research Reactors fuel materials research.