Numerical analysis of effective thermal conductivity associated with microstructural changes of porous SiC as an inert-matrix

In order to develop inert matrix material, evaluation of physical and chemical properties required for sintered nuclear fuel candidate materials were performed for more appropriate candidate material selection. Active research is being carried out to develop a new inert matrix material, e.g. ZrO2, MgAl2O4, ZrSiO4, and SiC, that prohibits the formation of Pu and actinides. Based on the experimental results, pressureless sintered SiC was considered to be the most appropriate candidate material. Microstructure and thermal conductivity changes were examined of the porous SiC. Effective thermal conductivity decreased by increasing porosity and decreasing the ratio between gas thermal conductivity within pores and sintered material thermal conductivity. With same porosity level, pore size and distribution have little effect on effective thermal conductivity.