ガンマ線照射下にある高温水中でのステンレス鋼隙間内腐食挙動における溶存酸素の影響

Effect of dissolved oxygen on the corrosion behavior at the crevice surface in high temperature water under gamma-ray irradiation

佐藤 智徳  ; 端 邦樹 ; 加藤 千明   ; 五十嵐 誉廣  

Sato, Tomonori; Hata, Kuniki; Kato, Chiaki; Igarashi, Takahiro

放射線照射下でのSCCき裂水質における溶存酸素濃度の寄与と深さ方向の水質分布を評価するため、隙間付与ステンレス鋼のガンマ線照射下試験およびラジオリシス解析を実施した。その結果、溶存酸素濃度によらず隙間内全域にFeOが形成されることを確認した。また、照射下では、き裂内でラジオリシスにより直接生成された酸化剤種は被膜成長で消費され、放射線環境下でもき裂内ではアニオン濃縮が発生することが推定された。

To evaluate the effects of dissolved oxygen concentration to water quality within SCC crack and the distribution of water quality in the depth direction under irradiation, immersion tests of stainless steel specimens given a gap and water radiolysis calculations for the water quality in the crevice gap were performed. As a result, it was confirmed that FeO was formed in the entire area within the crevice regardless of the dissolved oxygen concentration. It was also estimated that under irradiation, the oxidant species produced directly by radiolysis in the crack are consumed by the oxide growth, and anion enrichment occurs in the crack even in the irradiation conditions.