The principal objective of this paper is to show that we developed an experimental setup and a dissolution-passivation monitoring technique for use in super critical water oxidation (SCWO) conditions (T>374.15degreesC, P>22 MPa). The principal barrier to this technology development is the corrosion of the reactor materials. High corrosion rates were experienced in industrial plants. A major goal is to develop effective tools to determine and control the electrochemical and corrosion parameters. Until now, electrochemical data concerning metallic materials submitted to aqueous solutions at pressures and temperatures beyond the critical point are scarce. This research, in the context of organic wastes SCWO, first proposes, for both sub and supercritical conditions, technical solutions for an electrochemical cell able to give access to quantitative electrochemical information in aggressive solutions (pHgreater than or equal to1.5 and chloride ions content of 1 gL). Its second purpose is to obtain information on a titanium alloy (T60 grade) behavior in such conditions. The present study leads to a model establishing a reaction mechanism, which operates under normal conditions of pressure and temperature and can be extended to supercrifical ones. The limits of use of this material as a plant reactor material for supercritical water oxidation (SCWO) are evaluated. (C) 2004 The Electrochemical Society.