2018 | AFC ACCOMPLISHMENTS 45 Accomplishments Sample fabrication took place in the Fuel Research Laboratory at LANL. In order to investigate the mechanical response of the synthesized fuels. The RUS was performed from room temperature up to 500 K mechanical testing in collaboration with B. Maiorov (Magnetic Laboratory, LANL; Figure 1). RUS is a non-destructive technique that provides high accuracy measurements of elastic moduli.The technique is useful for measurement of the elastic properties of the bulk structure of various materials and different compositions. RUS measurement generates mechanical full body resonance spectrum. From this spectrum, an inversion scheme can be used to extract the elastic moduli. In this study, RUS is used for the first time to determine the prelimi- nary basic elastic properties at high temperatures of high density CeO2, UO2 and U3Si2.The independent elastic constants C11, C44 and the bulk modulus have been evaluated to calculate theYoung’s Modulus and the Poisson’s ratio to provide data for ongoing and future studies of the fundamental behavior of these materials and conjugate mixed oxide studies.The results of this study contributed to the mechanical data- base for U3Si2 determined using RUS up to 500 K (Figure 2). These data provide a baseline for future mechanical testing studies at higher temperatures (a new RUS cell running up to 900 K is in preparation) where irradiation or other stimuli are employed to alter the structure and chemistry of these candidate nuclear fuel materials.