Copper Corrosion Modelling for Applications in a Deep Geological Repository - Preliminary Results and Experimental Comparisons

摘要

Deep geological repositories (DGRs) are being used as long-term storage solutions by many nuclear agencies. Canada's DGR, designed by Nuclear Waster Management Organization (NWMO), consists of multiple engineered barriers including a steel container for strength, a copper coating for corrosion protection, and a bentonite buffer to minimize transport of corrosion compounds. The copper barrier will undergo corrosion with time which can include uniform corrosion, stress corrosion cracking, or microbiologically induced corrosion. In this study, uniform corrosion of copper is taken into consideration and the mechanism of copper corrosion is modelled to predict the long-term corrosion behavior of copper used in the Canadian used fuel containers. Simulation of the copper corrosion process was based on the copper corrosion model (CCM) and implemented in COMSOL Multiphysics. The one-dimensional model included a steady-state and transient simulation that included precipitation and dissolution of solid copper (II), Cu2O, as well as, adsorption and desorption of Cu(II). Preliminary results suggest a reasonable fit with rotating-disc electrode experiments. The aim of the project was to develop a model that was parametric, leading to a fully three-dimensional model and aid in the design of the containment system for used nuclear fuel.