The Development of a microstructural model to evaluate the irradiation-induced property changes in IG-110 graphite using X-ray tomography

Sumita, Junya; Shibata, Taiju; Kunimoto, Eiji; Hall, G.*; Marsden, B. J.*; Sawa, Kazuhiro

Securing the Safe Performance of Graphite Reactor Cores, p.163 - 170, 2009/12

In order to develop a microstructural / property change model of fine-grained IG-110 graphite, one of candidates for core components for VHTR, the relationship between changes in the bulk properties and the microstructure of IG-110 graphite are being investigated. In this study, a microstructure of IG-110 graphite was changed by thermal oxidation and the change of it was measured by electrical resistivity. Then, the applicability of X-ray tomography, which has been thought to be difficult to apply to IG-110 graphite due to limit of resolution of apparatus, was investigated. The following results were obtained. (1) IG-110 graphite samples were oxidized uniformly in atmosphere at 500 C and we got the relationship between electrical conductivity and burn-off (porosity) of IG-110 graphite. (2) Three-dimensional images based on the high resolution X-ray tomography can be used to describe the microstructure change of IG-110 graphite. It is expected this method can be used to predict the changes in the bulk properties of irradiated IG-110 graphite.