Fabrication and characterization of MOX fuel for fast neutron reactor: a guided journey from powder to pellet

This manuscript follows a representative MOX specimen, illustrated by the mascot MOX-kun, through the successive manufacturing and characterization steps performed at the Plutonium Fuel Development Facility (PFDF), a research laboratory of the Japan Atomic Energy Agency (JAEA) located in Tōkaimura, Ibaraki, Japan. Throughout its journey, the specimen is exposed to a wide range of processing conditions, from powder conditioning and intensive ball milling to pellet pressing, high-temperature sintering under carefully controlled atmospheres, and long-term self-irradiation during storage. Rather than focusing on a single processing step or characterization technique, this article provides an integrated, end-to-end perspective of laboratory-scale MOX fuel fabrication and characterization based on the expertise developed at PFDF. By combining technical explanations with an intuitive visual narrative, it offers a didactic overview of the main manufacturing processes and characterization approaches involved in MOX fuel research, making this highly specialized field more accessible to both newcomers and experienced professionals while highlighting the scientific challenges that continue to drive advances in MOX fuel technology.