Corrosion issues in nuclear waste storages and disposals

MasterThe corrosion resistance of materials in interim storages and in underground repositories is an important issue for the safe disposal of High Level Radioactive Waste (HLNW). The reliable prediction of container degradation rate and engineering barrier integrity over extended periods, up to several decades for interim storages and up to thousands years for disposals, represents one of the greatest scientific and technical challenges. Clearly, the reliability and the viability of integrity predictions are of paramount importance in assuring the public that safe disposal can be achieved. These issues are discussed, compared, and explored with the corrosion community, which has to face new challenges for corrosion prediction on a scientific and technical basis. The scientific and experimental approaches are being developed in various organisations worldwide for predicting long term corrosion phenomena, including corrosion strategies for interim storages and geological disposals. Among the comparison items, the following should be emphasized oThe importance of the underground repository conditions that leads to the choice of different materials for different environments passive, high alloyed materials for unsaturated conditions (USA), copper in granite repositories (Sweden, Finland), and carbon steel in specific clay conditions (France). oThe necessity of developing predictive models that must be based on the mechanisms of corrosion phenomena and whose outputs (predictions) are constrained by the natural laws. oThe use of archaeological artefacts to demonstrate the feasibility of long term storage and to provide a database for testing and validating the models. Other issues that are evolving as the various technologies are also developed