Effect of tritium and dissolved oxygen on anodic polarization of SUS304 stainless steel in sulfuric acid solution

Oyaizu, Makoto; Isobe, Kanetsugu; Hayashi, Takumi; Yamanishi, Toshihiko

Since exotic corrosion of stainless steels in tritiated water can be expected, anodic polarization of SUS304 stainless steel sample in approximately 5wt.% sulfuric acid solution were performed at various concentrations of tritium and dissolved oxygen (hereafter DO) in the electrolyte. The inhibitory effect of tritium on the passivation could be observed with DO even at a tritium concentration electrolyte as low as 2.2 kBq cm. This effect became more pronounced as the tritium concentration increased. It was suggested that the inhibitory reaction depending on tritium concentration would compete with the self-passivation depending on DO concentration (hereafter [DO]), since there was found to be a threshold [DO] for self-passivation at each tritium concentration.