Fuel Element for an Affordable NTR

Howe Industries LLC will investigate, design, and demonstrate the fabrication of fuel elements for a safe, robust NTR - the Scored Plate Reactor as an Innovative Nuclear Thermal Rocket -- SPRINTR. This design will enable a compact, safe, robust, NTR to be designed that emits clean exhaust, high specific impulse, high thrust to weight, intrinsic subcriticality in accident scenarios, and affordability. The SPRINTR design uses a stack of thin plates of fuel which have radial grooves etched into the top surface. The size of the grooves, number of grooves, and thickness of the plate can be varied to match power density. The coolant flow is a folded flow path identical to the particle bed reactor but the solid fuel form solves the problems of matching the power density. The flat plate fuel element allows extreme ease of manufacture and allows coatings to be easily applied if needed. The basis of the concept will utilize LEU loaded tungsten fuel. This will allow retention of all radioactivity and clean exhaust. Clean exhaust will enable much more affordable ground based testing facilities to be considered. Separating each fuel plate will be graphite composite plates. These will be unloaded graphite which will moderate neutrons and provide a more thermal neutron spectrum. By providing a more moderated neutron spectrum, much less LEU will be required in the tungsten fuel. In the event the graphite elements crack or erode, no radioactivity or fuel is lost to the flow stream. Due to advancements in cermet fuels, the SPRINTR can succeed where previous flat plate designs struggled. The proposed design allows for simple manufacturing, effective heat transfer, high thrust, and low mass.