The development of new nuclear reactors and the operation of existing reactors beyond their standard operating envelopes are critical to solving a variety of challenges, including the provision of large quantities of clean energy and the reliable generation of electricity or heat in remote terrestrial or extra-terrestrial environments. Understanding the response of nuclear materials under extreme conditions will support the qualification of Zircaloy-UO₂ fuel beyond current burnup limits and the development of advanced fuels, including high thermal conductivity ceramics, fuels containing Pu and/or minor actinides, molten salts, liquid metals and cladding materials, such as SiC-SiC and novel alloys. The response of these materials under extreme temperature, irradiation and chemical conditions is controlled by complex phenomena that span a large range of phase space, length scales and time scales. The combination of mechanistic models (implemented at the engineering, meso-, and atomic scales) with a wide variety of advanced experimental techniques is poised to provide the tools necessary to accelerate the deployment of new and innovative nuclear fuel technology. Modeling and experimental integration through uncertainty quantification and validation, as well as scale bridging and machine learning, are expected to play a crucial role.

actinide defects Lanthanide nuclear materials radiation effects