Preparation and Performance of Fully Ceramic Fuel Element Using Silicon Carbide as Coating Layers

摘要

Tristructural-isotropic (TRISO) coated foel particles with spherical ceramic foel kernels followed by three layers of pyrolytic carbon and one layer of SiC is successfully used in high temperature gas cooled reactor (HTGR) system. In this paper, an improved design concept of folly ceramic foel is proposed. The kernels were coated by SiC layers with different densities. Two kinds of SiC coatings, namely porous SiC and dense SiC were prepared by a fluidized bed chemical vapor deposition method. The densities of porous SiC and dense SiC were 1.40 g/cm~3 and 3.20 g/cm~3, respectively. By controlling experimental parameters, densities of the SiC layer can be adjusted. The structure and micromorphology of the coated particles were investigated by various technologies such as XRD, SEM, and EDX. The coated particles were dispersed in SiC matrix and further sintered to dense compacts. High temperature oxidation test confirmed the robustness of the foel elements.