Detailed information about corrosion processes affecting the stability of canisters containing nuclear waste is important input for the Safety Case. The goal of the project ConCorD is to obtain detailed information about corrosion behavior for candidate canister materials under geochemical conditions expected to prevail in a clay-based repository, with an emphasis on processes occurring under transient conditions (e.g., chemical, redox) of the early repository post-closure phase. The structure of the corrosion products formed in dedicated laboratory experiments and the evolution of the surface morphology are investigated in detail by application of various modern analytical techniques. The goal is to obtain a reliable description of the underlying processes in order to allow a robust quantification and evaluation of the involved degradation processes.