2018 | AFC ACCOMPLISHMENTS 43 Project Description The Office of Nuclear Energy (NE) currently funds work at Los Alamos National Laboratory (LANL) focused on the investigation of novel ceramic nuclear fuel concepts under the Advanced Fuels Campaign (AFC). One of the primary performance objectives targeted for improved performance of nuclear fuels is fracture toughness. New materials or composite fuel architectures that offer greater resistance to cracking under the extreme environments encountered during nuclear reactor service would provide significant improvements to steady state (e.g., heat transfer, fuel redistribution) and transient (e.g., radionuclide release at elevated temperatures) conditions. Options currently under investigation include ‘nontraditional’ nuclear fuels designated around high uranium density.These include uranium silicides, uranium borides, and composite fuel materials constructed of these and uranium nitride or uranium dioxide. Preliminary screening of the thermophysical and thermodynamic properties of these concepts has provided confidence in their soundness, but evaluation of their mechanical properties at relevant temperatures must be executed in order to support further study. Coupling the tools available in the Fuels Research Laboratory and at the Magnetic Laboratory, will enable synthesis and mechanical measurements of these novel nuclear materials. This work will aim to provide baseline mechanical properties for these fuels in the unirradiated state to lay the groundwork for future extension to both higher temperatures (more relevant for nuclear reactors) and ion beam irradiations.