Extrusion-based additive manufacturing of zirconium carbide for nuclear fuel cell structures

Abstract

Nuclear thermal propulsion relies on heating hydrogen propellant using nuclear fuel to generate thrust for spacecraft propulsion. Ceramic fuel elements like zirconium carbide (ZrC) offer advantages over metals due to their high melting points and high temperature stability. The primary function of ZrC in this context is to provide structural integrity and stability to the nuclear fuel, especially under high-temperature and high-radiation conditions. Vanadium carbide (VC), with similar properties, is being used as a sintering additive for ZrC to enhance densification and mechanical properties. Traditional ZrC fabrication methods struggle with intricate geometries, but additive manufacturing (AM), specifically extrusion-based methods, revolutionizes ceramic fabrication by offering material flexibility, multi-material printing, minimal waste, and rapid prototyping. This study explores extrusion-based AM for the fabrication of ZrC nuclear fuel cell structures. Experimental findings highlight the impact of Nano Crystalline Cellulose (NCC) and VC additives on 3D-printed ZrC ceramics: higher NCC concentrations improves ink recovery and reduces deformation during the printing process, but excessive NCC increases the porosity after sintering process; VC additives mitigate decreased mechanical properties caused by higher NCC content, emphasizing the crucial role of ink composition and additive selection in achieving desired material properties for broader applications. These insights pave the way for innovative approaches in AM structures for nuclear propulsion and other high-performance applications. The integration of AM technologies with advanced materials like ZrC and tailored additives represents a significant step towards efficient and sustainable propulsion systems for future space exploration missions.