Title: Corrosion in nuclear waste geological storages: How to predict corrosion for millenniums ?”
This lecture gives an overview of the main corrosion issues related to geological disposal of high-level nuclear wastes (HLNW). In addition to summarizing some specificities of the French concept for geological repository (clay underground repository concept, HLNW mainly composed of glass matrix, ), the French approach for the selection of the material (non-alloy steel) of HLNW overpacks is underlined with (i) the combination of experimental works and semi-empirical modelling for initial estimation of service life-times, (ii) mechanistically based modelling for more robust and reliable prediction, (iii) the use of archaeological artefacts to provide data base for testing, and (iv) validating models, and the importance of integrated experiments in underground laboratories. The whole approach is iterative and includes the integration of the evolution of knowledge.
Title: Overview on Corrosion in supercritical fluids
Whatever is the supercritical fluid, the performance of structural materials is a key issue for industrial applications. An overview is carried out on the corrosion behavior of metallic metals and alloys under pressure and temperature conditions appropriate for supercritical fluids. Steels, including stainless steels, and nickel base alloys are the main alloys investigated in supercritical environments. In supercritical water (SCW), the review highlights how SCW density changes the corrosion mechanisms. Beside the density, temperature and impurities (especially chlorine) play key roles. SCW oxidation is promised to a strong development if corrosion issues are solved, as illustrated with the DELOS process for destruction of radioactive organics.
In other supercritical fluids like supercritical CO2, authors observed that no corrosion occurs in pure SCF but the water content is a key parameter. Temperature, water and pollutants are the major factors leading to increase uniform or localized corrosion rates.
Speaker: Prof. Damion Feron, CEA-Saclay, Bat 458, PC50 , Gif-Sur-Yvette, France