The thermal properties of tristructural isotropic (TRISO) particle coatings have been measured using laser-based thermoreflectance methods from room temperature to 900 °C. At room temperature the pyrocarbon coatings have comparable thermal conductivities below 10 W·m-1·K-1, whereas the SiC coating has a thermal conductivity around 90 W·m-1·K-1. The thermal diffusivities of all coatings display significant reduction with increasing temperature. The thermal conductivity of SiC decreases by more than 25% above 800 °C and the thermal conductivities of pyrocarbons increase moderately with the temperature, displaying similar changes to that of amorphous graphite at elevated temperatures.
