Effect of temperature on corrosion behaviors of copper in high-level nuclear waste disposal environment

Deep geological disposal was considered a safe and efficient strategy for nuclear waste disposal. However, the corrosion of metallic disposal containers in the disposal repository environment is easily affected by the variation of temperature. The purpose of this work is to crystallize the effect of temperature on the corrosion behaviors of copper in simulated Beishan underground water solution (0.1 M NaHCO 3 +0.05 M NaCl+0.05 M Na 2 SO 4 solution). The corrosion behaviors of copper in the tested solution at 25 °C, 45 °C, and 75 °C were investigated using electrochemical techniques, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The results showed that the increase in temperature can accelerate both cathodic and anodic reactions, thereby increasing the corrosion current density. The open circuit potential (OCP) at 25 °C and 45 °C remained relatively stable at about −100 mV. The polarization resistance decreased in different degrees from 1 to 10 days at various temperatures. Then the polarization resistance gradually increases with the formation of corrosion products. The presence of Cu 2 (OH) 2 CO 3 at 45 °C can provides superior protection ability for the sample against corrosion.