2017 | AFC ACCOMPLISHMENTS 70 Thermal conductivity values have been calculated for the UO2-UB2 composites from measured thermal diffusivity values and from calcu- lated, based on the rule of mixtures, specific heat and thermal expansion values and are show in Figure 3.The specific heat values for the composites were calculated based on UB2 data from Fredrickson et al. [3] while the thermal expansion of UB2 was taken from White [2]. Equivalent data for UO2 were taken from Fink [1].The thermal conductivity of these samples was calculated to 873 K.As expected, based on the thermal diffusivity data, the thermal conductivity of UO2-UB2 samples were shown to increase as the weight fraction of the UB2 phase increased.As with the diffusivity data, the UO2-30%wt UB2 sample was calculated to have the highest increase in thermal conductivity, namely 50%, compared to UO2. An initial screening of the thermo- physical properties of the produced UO2-UB2 composites was carried out from 300 to 873 K and a significant increase in the thermal conductivity, compared to UO2, was found for a UO2-30%wt UB2 sample.This deems the UO2-UB2 composite system as a potential candidate for ATF, although the economic impact due to enrich- Figure 2. Thermal diffusivity as a function of temperature for UO2-UB2 (squares) and UO2-UB4 (circles) composites along with reference thermal diffusivity data on UO2 [3] and UB2 [2].