Ti3SiC2/UO2 composite pellets with superior high-temperature thermal conductivity

Ti3SiC2 with a continuous network structure was introduced to UO2 to improve the thermal conductivity of UO2. A dense microstructure with a clean Ti3SiC2-UO2 interface was obtained using the spark plasma sintering (SPS) method. Ti3SiC2 exhibited high thermal conductivity at elevated temperature, and a coefficient of thermal expansion (CTE) close to UO2. Therefore, the thermal conductivity of Ti3SiC2/UO2 was greatly improved compared to that of UO2, particularly at high temperature. The enhancing effect of Ti3SiC2 even exceeded those of SiC and BeO above the working temperature of fuel pellets. This improvement in thermal conductivity is of great importance for enhancing the fuel safety under accident conditions.