Corrosion of reactor materials under irradiation is reviewed and discussed from the standpoint of the effect of: (1) radiation damage in metals, (2) radiation damage in oxide film, and (3) radiation effect on corrosion environment.
Radiation damage on metal surface stimulates the dissolution of the metal into aqueous solution and reduces its electrode potential. Studies at Harwell and ORNL have proved that high temperature aqueous corrosion of Zr and Zry-2 is accelerated by damage in the metal substrata rather than on the surface oxide film.
The effect on corrosion brought by damage in the oxide film is explained in terms of increases in density, in electronic conductivity, in diffusivity and in surface chemical reactivity.
Radiolysis of the aqueous environment also influences the corrosion of metal through changes in the electrochemical properties of solution and of metal electrode.