Fabrication of mini UB2 ingots via Arc melt synthesis using a customized copper hearth

Abstract

As growing efforts take place to enhance the operational safety of nuclear reactors, fuel composites have been explored as replacement to the traditionally used Uranium dioxide (UO2). One potential candidate that has been gaining momentum as a fuel composite additive is Uranium diboride. UB2 is known to have a higher uranium density and higher thermal conductivity than UO2, properties that would allow for a lower enrichment of the fuel pellets as well as improve the temperature gradient across the pellet during reactor operation. While various challenges arise when considering UB2 as a drop-in replacement to UO2, UB2 has shown much promise as a composite fuel when combined with other uranium compounds such as U3Si2.Through the use of an arc-melter system, 50-250 mg ingots of UB2 were fabricated using the fragments of a larger 2-5 g ingot of UB2. X-Ray diffraction analysis was performed to confirm the purity of the initial UB2 ingot. Further, an infrared camera was used to monitor the temperature of the furnace chamber during the mini-UB2 bead fabrication. The purpose of this project is to understand the fabrication process of UB2 and characterize the micro-structure of the as-fabricated mini fuel beads. We wish to better understand the viability of UB2 as a potential fuel composite additive.