2017 | AFC ACCOMPLISHMENTS 76 Separate Effects Investigation on the Role of Oxygen on Fresh Fuel Properties of U3Si2 Principal Investigators: J.T. Dunwoody Collaborators: J.T.White and A.T. Nelson Figure 1. Thermal diffusivity collected for U3Si2 pellets containing varying levels of oxygen. Five sample sets were synthesized with feedstocks containing oxygen at levels sufficient to produce 2, 4, 6, 8, and 10 volume percent UO2. The 2% and 10% trend lines are the degradation expected for the respective volume fractions UO2 in a U3Si2 matrix as calculated from a rule of mixtures approximation. Data for high purity, high density U3Si2 is also shown for reference. Amajor challenge presented by numerous Accident Tolerant Fuel (ATF) concepts is the scale of fabrication necessary for commercialization. Industrial fabrication of U3Si2 fuel will likely require modifications from the controls of the laboratory as presently employed. One likely outcome of adaptation to higher throughput production will be increased oxygen content. A signifi- cant unknown for this fuel system is how this oxygen affects the proper-