| Abstract Scope |
Graphite is one of the most important structural materials for TRISO fuels. Different from nuclear-grade graphite, matrix-grade graphite has a small amount of incompletely graphitized binder, which makes it vulnerable to oxidation. Only few studies dealt with the oxidation behaviors of matrix-grade graphite in air ingress accident scenarios, even though water vapor ingress is more probable than air ingress for high temperature gas-cooled reactors (HTGR). Thus, oxidation properties, microstructure changes, and mechanical properties should be studied in order to predict and analyze matrix graphite performance under HTGR accidental conditions. In this study, the oxidation behaviors of ARB-B1-Z007 matrix-grade graphite were investigated. The postulated water vapor ingress conditions were 800–1200 °C in He/10–40 vol% water vapor mixed atmospheres. Mass change, evolving gas, composition, microstructure, and mechanical properties were analyzed. The resultant understanding can be applied to the development of new graphitic materials and design of new HTGR fuel systems. |