Corrosion behavior of FBR structural materials in high temperature supercritical carbon dioxide

Furukawa, Tomohiro  ; Inagaki, Yoshiyuki; Aritomi, Masanori*

Corrosion test of high-chromium martensitic steel (12Cr-steel) and FBR grade type 316 stainless steel (316FR) were performed at 400-600 C in supercritical CO pressurized at 20MPa. High temperature oxidation was measured up to approximately 2000h in both steels. In the case of 12Cr-steel, the weight gain showed parabolic growth with exposure time at each temperature. The oxidation coefficient could be estimated by the Arrhenius function. The specimens were covered by two successive oxide layers. In the case of 316FR specimens, the weight gain was significantly lower than that of 12Cr-steel. Dependency of neither temperature nor exposed time on oxidation was not observed. Nodule shape oxides were observed on the surface of the 316FR specimen. Carburizing, known as a factor in the occurrence of breakaway corrosion and/or the degradation of ductility, was observed on the surface of both steels.