Radiation-induced preferential dissolution of specific planes of carbon steel in high-temperature water

With respect to carbon steel, corrosion examinations are performed in boiling water under the conditions of with and without exposure to γ-rays. Simulating a radiation-induced concentration cell, one set of samples is connected to the anode of external battery, while the other to the cathode. The corrosion current monitored during the corrosion and weight loss measurement after a prescribed corrosion period have revealed that corrosion rate under γ-rays is six times larger as that under a non-irradiated condition. An interesting feature observed by XRD analysis is that γ-ray exposure remarkably enhances the preferential dissolution of a specific (1 1 0) plane, which potentially triggers an occurrence of the pitting corrosion and an incipient crack; tensile stress being superposed, cracks like IASCC are implied to readily initiate and propagate through materials. Several measures against IASCC often found in the existing nuclear plants are envisaged in the light of controlling a radiation-induced concentration cell formation reported before.