The electrochemical behavior of tritium-containing stainless steel in alkaline medium

Abstract

Abstract The electrochemical behavior of 304L stainless steel sheets was studied by cyclic voltammetry in 0.1M NaOH. The hydrogen produced by electrolysis at values more negative than −1.6 V diffuses into the electrode; at more positive potentials, it diffuses back towards the surface, where it is reoxidized. Application of a potential step from −1.6 to −0.3 V produces a current which obeys the semi-infinite diffusion equations. Sheets contaminated by tritium were studied on the basis of the above results. At −0.3 V, the oxide layer is not destroyed; the tritium which it contains is oxidized and passes rapidly into the solution; smaller amounts, due to the tritium diffusing from the bulk of the metal, are subsequently oxidized. At −1.3 V, essentially the same phenomenon is observed, except that the oxide layer is destroyed. At −1.6 V, penetration of hydrogen occurs concomitantly to the oxidation of tritium. Applications to the decontamination of tritium containing steel are discussed.