2018 | AFC ACCOMPLISHMENTS 42 2.2 HIGH-PERFORMANCE LWR FUEL DEVELOPMENT Mechanical Properties of LWR Fuel Materials at Elevated Temperatures Principal Investigator: Ursula Carvajal-Nunez Collaborator: B. Maiorov Figure 1: RUS cell used for this study. a) Cell set- up with a reference sample. We used the Rescor311 + waterglass composite that showed desired ultrasound properties but was mechanically fragile. Thin alumina wear plates were added (bonded to transducer) to improve conditions for resonance. The properties of Uranium Silicides (U-Si) nuclear fuel pellets play an important role in the reactor. Evaluation of the mechanical properties to reactor relevant temperatures is necessary for fuel performance codes. Measurement of mechanical properties of conventional ceramic and intermetallic nuclear fuel materials is challenged by the fact that brittle failure dominates practical relevance at low temperatures. Resonant ultrasound spectroscopy (RUS), a non-destructive technique, provides a demonstrated alternative to traditional mechanical test methods.The technique is useful for measurement of the elastic properties of the bulk structure of various materials. RUS is used to determine the basic mechanical properties of high density U3Si2 from room temperature up to 500K.The independent elastic constants C11, C44 and the bulk modulus have been evaluated to calculate theYoung’s Modulus and the Poisson’s ratio.