2018 | AFC ACCOMPLISHMENTS 126 3.1 FUELS DEVELOPMENT Annular Extrusion Development Principal Investigator: Randall Fielding Collaborators: Brady Mackowiak, Ginger Dexter, Robert O’Brien Annular fuel has been proposed as an advanced fuel concept, with initial results showing positive results. In addition to casting, extrusion has been shown to be a viable metallic fuel fabrication process. Extrusion will likely have advantages over casting for annular fuel fabrication because casting of thin walled tubes using standard casting technique has shown to be very difficult.This work looks into the feasibility of extruding annular U-Zr fuels. Project Description: EBR-II fuel was traditionally fabricated through casting of the fuel. Although casting has been proven to be an efficient process to fabricated large quantities of fuel it may not be as efficient for some advanced fuel concepts, such as annular fuel. A mechanically bonded annular fuel may be applicable to high burnup application, may have a positive impact on reactor design, and will not require sodium as a thermal transfer media, which may simplify the final disposition path for the used fuel. Because the fuel will be mechanically bonded a tighter control of surface finish and final dimensions as compared to traditional sodium bonded will likely be necessary. In the metal forming industry, extrusion is a common process that is used to produce tubular products with good dimensional control and surface finish, although for a finer surface finish further warm or cold processing may be necessary. Another potential advantage of extrusion is the ability to co-extrude a composite product, producing a multi-layer product. Extrusion may be a feasible fabrication approach to produce annular fuel rods, with a fine surface finish, and tight dimensional control. If a suitable material can be extruded with the fuel, a fuel cladding chemical interaction barrier may also be applied at the same time while reducing contamination spread during the fabrication process.Another fuel concept that becomes feasible with extrusion is an axially graded fuel. In this work the feasibility of extrusion for advanced, especially annular, fuel fabrication is shown. Accomplishments: Dr. Robert O’Brien collaborated on the segmented billet experiment design, while Brady Mackowiak and Ginger Dexter were instrumental in extrusion processing and characterization of the extruded product.