Preliminary Concepts of an Automated Additive Manufacturing System for Accident Tolerant Uranium Silicide Fuel Pellets

Abstract

Traditional methods of manufacturing nuclear fuel are labor intensive and costly, generally including extrusion or sintering processes and the use of substantially pure materials. The US Department of Energy is working to develop accident tolerant nuclear reactor fuels as alternatives to Zircaloy-4-uranium dioxide (UO₂) fuel systems. This could increase existing safety margins for nuclear plants while improving nuclear plant performance and decreasing maintenance and operational costs. Idaho National Laboratory has worked with Westinghouse to develop a new process called additive manufacturing as an Alternative Fabrication Technique (AMAFT) centered on the production of one such accident tolerant fuel, uranium silicide (U₃Si₂). A previous feasibility study performed with surrogate material demonstrates on a manual benchtop experimental setup that U₃Si₂ fuel pellets can be manufactured by selective laser melting (SLM). This report provides preliminary concepts to aid in process scale-up, including improvements that an automated system can provide for optimized and repeatable material properties. Automation and robotics provide further acceleration of commercialization with the potential to reduce manufacturing time, costs, and decreased material waste while decreasing or even eliminating direct handling of radioactive materials.