回転型腐食試験装置による気液交番環境での炭素鋼腐食の加速要因に関する検討

Study of factors accelerating corrosion of carbon steel by rotating-type corrosion test apparatus in gas/aqueous alternating environment

塚田 隆 ; 上野 文義  

Tsukada, Takashi; Ueno, Fumiyoshi

福島第一原子力発電所廃炉に向け格納容器等に用いられている鋼材の腐食挙動を予測する必要がある。格納容器内の気液界面付近や冷却水が流下する容器内面を想定し、炭素鋼(SGV480)試験片を気液中に交番曝露する回転腐食試験を実施した。その結果、交番曝露による腐食の加速が確認され、加速原因は鋼材表面に形成される薄い水膜の形成にあると考察した。本発表では、この腐食挙動に与える回転速度、酸素濃度、試験温度の影響を報告する。

It is necessary to predict the corrosion behavior of steel materials used for primary containment vessel etc. toward a decommissioning of the reactors at Fukushima Daiichi Nuclear Power Plant. The Rotating corrosion test of carbon steel (SGV 480) specimen was conducted by alternating exposure in gas/aqueous environments, assuming the vicinity of the gas-liquid interface and inner surface of the vessel where cooling water is flowing down. As a result, an acceleration of corrosion due to the alternating exposure was observed, and it was considered that a major cause of the acceleration is due to a thin water film formed on the surface of specimen. In this presentation, the influence of rotating speed, oxygen concentration and test temperature on the corrosion behavior will be presented.