Effect of ion polishing on corrosion resistance of the cladding of fuel elements from E110 alloy in the steam water environment

Abstract

The method of modification of the outer surface of the cladding of fuel elements from E110 Zr alloy by means of irradiation with a radial beam of Ar⁺ ions with a broad energy spectrum is proposed. It is shown that the use of ion beam treatment at the final stage of the cladding production can improve the surface quality owing to removal of a large part of surface defects after mechanical polishing. The kinetics of the growth of oxide films on ion-beam-treated (cleaning or polishing by Ar⁺ ions) tubular Zr alloy specimens in a steam environment (350, 375, and 400°C up to 3000 h) was investigated. Monoclinic zirconia layer formation is found to occur on the specimen surface oxidized at 350°C in water and steam environments. Oxidation of the fragments of the alloy fuel-element cladding in steam under pressure contributes to the formation of a thicker and more friable oxide film in comparison with the oxidation in water.