Thermal conductivity analysis of SiC ceramics and fully ceramic microencapsulated fuel composites

- Thermal conductivity of SiC ceramics and FCM pellets was measured and discussed.
- Thermal conductivity of FCM pellets was analyzed by the Maxwell-Eucken equation.
- Effective thermal conductivity of TRISO particles applied in this study was assumed.

The thermal conductivity of SiC ceramics and FCM fuel composites, consisting of a SiC matrix and TRISO coated particles, was measured and analyzed. SiC ceramics and FCM pellets were fabricated by hot press sintering with Al2O3 and Y2O3 sintering additives. Several factors that influence thermal conductivity, specifically the content of sintering additives for SiC ceramics and the volume fraction of TRISO particles and the matrix thermal conductivity of FCM pellets, were investigated. The thermal conductivity values of samples were analyzed on the basis of their microstructure and the arrangement of TRISO particles. The thermal conductivity of the FCM pellets was compared to that predicted by the Maxwell-Eucken equation and the thermal conductivity of TRISO coated particles was calculated. The thermal conductivity of FCM pellets in various sintering conditions was in close agreement to that predicted by the Maxwell-Eucken equation with the fitted thermal conductivity value of TRISO particles.