Effects of Radiation on Metallic Corrosion

Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

“…The experimental study of the effect of gamma radiation on the corrosion of stainless steel in 3% NaCl solution conducted by Byalobzheski (1970) showed that the corrosion rate was essentially unaffected after 1,200 hours exposure. Studies cited by Stobbs and Swallow (1962) in their review showed, similarly, that stainless steels in high-purity aqueous systems at temperatures up to 300°C and pH values around 10 are affected little by neutron irradiation.…”

“…For this reason, radiolysis Is a major concern when predicting canister (or overpack) life. However, the presence of hydrogen may cause the radicals to recombine quickly, thus mitigating corrosion and perhaps negating the effects of radiolysis altogether (Stobbs and Swallow, 1962).…”

“…Incident radiation can affect the corrosion resistance of metallic materials by affecting changes in: (1) the metal itself; (2) the protective layer; and/or (3) the corrodant. Researchers have concluded that gamma radiation principally affects the corrodant and does so by producing chemical changes (radiolysis) through excitation and ionization (Stobbs and Swallow, 1962;Byalobzheski, 1970;Wu, 1978), The primary radiolysis process in aqueous solutions is the decomposition of water to form short-lived radicals, e " H, OH and HO2, and the long-lived molecular products, H2 and H2O2, If in some manner the radiolytic H2 is continuously removed from the systeni, the oxidation potential of the solution will be increased. Conversely, in a closed system such as a sealed repository located in basalt where the hydrogen fugacity remains 2-238 RHO-BMI-ST-7 high (see Section 2.5), the radiolysis reaction will be suppressed and the oxidation potential will remain essentially unchanged.…”