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

X線トモグラフィーを用いたIG-110黒鉛の照射誘起特性変化評価用微細構造モデルの開発

角田 淳弥 ; 柴田 大受 ; 國本 英治; Hall, G.*; Marsden, B. J.*; 沢 和弘

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

超高温ガス炉の炉内構造物材料の候補であるIG-110黒鉛の微細構造変化による特性評価モデルを開発するため、現在IG-110黒鉛の特性変化と微細構造変化の関係について検討を進めている。本研究では、IG-110黒鉛の微細構造を酸化により変化させ、電気抵抗測定によりその変化を確認し、これまで装置の解像度の制限からその適用が難しいと考えられていたX線トモグラフィーのIG-110黒鉛への適用性について検討した。その結果、以下結論を得た。(1)IG-110黒鉛試験片は空気中500Cの条件化で均一に酸化されていることを確認し、IG-110黒鉛の酸化度(気孔率)と電気伝導度の関係式を得た。(2)高分解能3次元X線トモグラフィーを用いて、IG-110黒鉛の微細構造変化を描写できることを確認し、本手法を用いて照射したIG-110黒鉛の特性変化を予測できる見通しを得た。

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.