Corrosion Current Density of API 5L X65 Carbon Steel in Contact with Natural Callovian-Oxfordian Clay Pore Water, Assessed by Various Electrochemical Methods over 180 Days

Near-neutral pH and a low redox potential are considered favorable conditions for immobilizing radionuclides in deep repository systems within clay formations. Cigeo is the future French Industrial Center Geological Disposal high- intermediate-level long-lived radioactive waste, to be built at depth of 500 m Callovian–Oxfordian clay. In-depth knowledge mechanisms kinetics corrosion occurring on surface API 5L X65 (X65) carbon steel tubing essential reversible nuclear waste management site. By using all-solid robust handmade electrodes addition electrochemical gravimetric techniques, we determined phenomenology contact with natural Cox pore water equilibrium its rock gases, flowing continuously through multi-parameter probe device placed Bure Underground Research Laboratory, over 180 days. Two iron oxidants were encountered, namely, depleted dioxygen (O2) proton H(I), accompanied by hydrogen sulfide. Corrosion well established two electrodes, whether electrochemically perturbed or not. The thickness loss rates, both between 0.016 0.032 mm/year. This study demonstrates, site, reliability developed methodology continuous monitoring same time as temporal variation key geochemical parameters fluid was assessed.