Summary

In previous corrosion studies, carbon steels were identified as promising materials for the manufacturing of long-lived high-level waste containers that could act as a radionuclide barrier in a rock-salt repository. In the present work, the influence of some important oxidizing radiolytic products generated in gamma irradiated brines on the electrochemical corrosion behaviour of the preselected fine-grained steel TStE 355 was studied. The steel was examined by potentiodynamic and potentiostatic polarization methods at 90°C in a disposal relevant NaCI-rich brine containing radiolytic products such as H202, CIO-, CI03- and C104- at concentrations between 10-4 and 10-2 MI/. The polarization curves indicate that in all brines with and without radiolytic products, the steel exhibits active corrosion. A non-uniform general corrosion was observed without any signs of pitting corrosion. CI03- and CI04- additions of 10-4-10-3 M/I to the brine do not increase significantly the initial corrosion rate of the steel compared to the value in the pure brine. However, additions of CIO-and H202 to the brine change the cathodic process from activation polarization t