Nuclear corrosion: achievements et challenges
Résumé
The activities of the CEA corrosion department (Service de la corrosion et du comportement des materiaux dans leur environnement SCCME) are mainly concerned by the facilities of the nuclear fuel cycle. They include uranium separation and enrichment, fuel issues (thermodynamics and cladding interactions), nuclear reactors (generation 2, 3 and 4) and waste management (reprocessing plants and storage). In these various nuclear environments, corrosion science faces new challenges. It will be illustrated by three main areas where increases of knowledge and understanding have been done and are still needed to face the technical needs (i)the extension of the life time of nuclear power plants (NPPs) from 30-40 years as initially planned, to 60 years and probably more as expected now, and with mainly the stress corrosion cracking issues. (ii)The choice of materials for use at very high temperatures as expected in Generation IV power plants in various environments like gas (helium), supercritical water, liquid metals or salts. (iii)The prediction of long term behaviour of metallic materials in nuclear waste disposal where the corrosion processes have to be predicted over large periods of time, some thousands years and more.NPPs life time extension, deep geological waste repositories and high temperature reactors sustain researches and developments to model corrosion phenomena at various scales, from atoms to components, from nanoseconds to millennia. To conclude, some illustrations will be given on activities more related to decommissioning where fundamental knowledge, modelling and applied experiments are also needed.
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