Advances in fuel fabrication

Advances in the nuclear fuel cycle and the introduction of novel fuel forms necessitate advances in fuel fabrication that encompass not only the development of commercially scalable fabrication techniques for novel fuel forms but also innovative synthesis and fabrication methods for conventional reactor fuel. Fuel fabrication can entail several pivotal processes that lead to the implementation of a specific nuclear fuel form. Whether uranium dioxide (UO₂) clad in a zirconium-based alloy, such as Zircaloy, or tristructural isotropic (TRISO) particles dispersed in a graphite matrix, the fabrication techniques employed in the manufacturing of each nuclear fuel form are multifaceted. Since this book focuses specifically on the advances of nuclear fuel chemistry, the authors of this chapter narrows the scope of the broader term “fuel fabrication” and details specifically the synthesis techniques for a variety of actinide-bearing nuclear fuels, with little discussion to the cladding and containment aspects specific to each fuel form, unless it proves essential to the synthesis of the fuel itself (e.g., TRISO fuel particles). This chapter will cover the synthesis techniques for a variety of fuel forms starting from uranium metal or stable uranium precursor compounds that result from traditional conversion processes (e.g., UF₆, UO₃, and elemental uranium). Spanning the breadth of fuel cycle research and development, the chapter begins with a detailed description of conventional UO₂ fuel fabrication. The authors then introduce some of the latest techniques for oxide and ceramic fuel fabrication including an extensive discussion of nitride fuel fabrication followed by a brief discussion of the capabilities utilized to fabricate carbide and boride fuels. The latter sections of this chapter will detail techniques used for nonceramic fuel forms, specifically metallic fuel fabrication, and advance reactor fuels (accident tolerant, advanced gas reactor, and molten-salt reactor fuel).