Development and Validation of a Mixed‐Potential Model for the Corrosion of Copper Used Fuel Containers in Oxic Chloride Environments

Copper‐coated used fuel containers (UFC) may be exposed to Cl − ‐containing bentonite pore waters under oxic conditions. A mixed‐potential model has been developed to predict the time dependence of the corrosion potential ( E CORR ) and corrosion rate of the container as the near‐field environment evolves. Prediction of E CORR not only provides mechanistic insight into the evolution of uniform corrosion but also allows the assessment of the likelihood of localized corrosion and stress corrosion cracking mechanisms that are contingent on a threshold potential. Both 1‐D and 2‐D axisymmetric versions of the COMSOL‐based model have been validated against experimental measurements of E CORR of copper electrodes in which the mass transfer coefficient was varied over five orders of magnitude and the O 2 concentration varied over four orders of magnitude. Good agreement is found between the predicted steady‐state and transient values of E CORR and those measured experimentally.