2018 | AFC ACCOMPLISHMENTS 47 pressure to densify powders loaded into a graphite die at short timescales. SPS has been shown to densify materials with high melting points in reduced times and temperatures. Project Description: In this study, SPS was used to densify monolithic UB2 and UB4 pellets to high densities, i.e. higher than 90% theoretical density (TD) for thermal conductivity measurements since these values have not been reported in the literature.This is an important first step to increase understanding in these materials and assess the potential benefits in using them as part of composite accident tolerant fuel concepts since their thermal conductivity is expected to be significantly higher than that of UO2. PreviouslyWhite (2015) had measured the thermal conductivity of conventionally sintered UB2 but these values were measured on an 80% TD pellet and are therefore expected to be significantly lower than the measurements performed on high density pellets, fabricated by SPS.The UB2 and UB4 materials for this study were synthesized via arc melting and the resulting buttons were crushed, milled and sieved to produce the feedstocks used in this study.The feedstocks were then shipped to Rensselaer Polytechnic Institute (RPI) where the SPS was Figure 2: XRD results of (a) UB2 and (b) UB4 samples sintered by SPS at 1750 ˚C compared to reference data.