Both ZrC and SiC layers are crucial layers in TRISO coated fuel particles since they prevent diffusion of fission products and provide mechanical strength for the fuel particle. However, each layer has its own defects, so the purpose of this study is to determine such defects in these layers. In this study, we carried out thermodynamic simulations before actual experiments. With these simulation results, we deposited the ZrC layers on SiC/graphite substrates through a CVD process. SiC films on graphite have different microstructures which are a hemispherical angular, domed top and faceted structure at different deposition temperatures. According to the microstructures of SiC, the preferred orientation, hardness and elastic modulus of deposited ZrC layers are changed. New combinations of coated ZrC/SiC/graphite were made to improve mechanical properties and chemical properties for the purpose of fabricating TRISO coated fuel particle with high stability.

Keywords: SiC, ZrC, Preferred orientation, Microstructure, Mechanical property.