Evaluation of material properties of IG-110 and IG-430 from their microstructure

Sumita, Junya ; Shibata, Taiju ; Osaki, Hiroki*; Eto, Motokuni*; Konishi, Takashi*

Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR). The HTGR is particularly attractive due to its passive and inherent safety features. The Very High Temperature Reactor (VHTR) is one of the most promising candidates as the Generation-IV nuclear reactor systems. IG-110 graphite having high strength and resistance to oxidation is used in the HTTR of JAEA and HTR-PM in China. IG-110 graphite is also a major candidate for the in-core graphite components of VHTR, too. IG-430 graphite having the higher strength and resistance to oxidation than IG-110 is an advanced candidate for the VHTR. In this study, the elastic modulus and coefficient of thermal expansion of these graphites were measured and correlation of compressive strength and microstructure was evaluated. Moreover, the densification effects on the material properties were discussed from the standpoint of microstructure using X-ray tomography method.