Oxidation behaviors of SiO_2/SiC coated matrix graphite of high temperature gas-cooled reactor fuel element

摘要

The improvement of the oxidation resistance of graphite is important for the safety of high temperature gas-cooled reactor. The validity of applying SiO_2/SiC coatings to improve the oxidation resistance of matrix graphite of high temperature gas-cooled reactor fuel element under possible conditions is evaluated through experiment. It is found that SiO_2/SiC coatings greatly decrease the mass loss rate of matrix graphite during oxidation both in air and in argon with little oxygen. After heating in high purity helium at 1000 C for 100 h, SiCh/SiC coatings can keep their stability and still effectively protect matrix graphite from oxidation. The fabricated SiO_2/SiC coatings have an excellent thermal shock property also.