Effect of re-oxidation rate of additive cations on corrosion rate of stainless steel in boiling nitric acid solution

沸騰硝酸溶液中のステンレス鋼腐食速度に及ぼすカチオンの再酸化反応速度の効果

入澤 恵理子 ; 山本 正弘 ; 加藤 千明   ; 本岡 隆文; 伴 康俊  

Irisawa, Eriko; Yamamoto, Masahiro; Kato, Chiaki; Motooka, Takafumi; Ban, Yasutoshi

The boiling nitric acid solution containing highly oxidizing cations dissolved from the spent nuclear fuels corrodes stainless steels because of the nobler corrosion potential and their fast reduction rate. The cations themselves are re-oxidized to higher oxidizing states in a bulk solution after the corrosion reaction. In this paper, the re-oxidation rate constants of typical cations, such as Cr, V, Pu, and Np, were analyzed, and discussed about the effect on time dependencies of the corrosion rate. It was indicated that the cations with a large re-oxidation rate constant, such as Np, could keep the corrosion rate at high level continuously for the long immersion duration.