Lionel Thome (CNRS-IN2P3-Universite Paris-Sud, Orsay, France), Radiation Effects in Nuclear Materials

Wednesday 2 Feb 2011, 11:00 → 12:00 Europe/Bucharest

A long history of research has shown that ceramic oxides and carbides are among the most promising matrices for the immobilization and/or transmutation of nuclear wastes, cladding materials for gas-cooled fission reactors and structural components for fusion reactors. For all these applications, there is an urgent need of data concerning the behavior of nuclear ceramics upon irradiation. Radiations produced in nuclear reactors or in storage forms may be simulated by external irradiations with various types of ions in a broad energy range. The two main slowing-down regimes (Sn and Se) were distinctly investigated: low-energy heavy ions account for the recoil nuclei arising from the alpha-decay of actinides (Sn); swift ions aim to reproduce the impact of fission fragments (Se). In this lecture, we present a few remarkable examples concerning ion-beam modifications of nuclear ceramics (zirconia, pyrochlores, silicon carbide...) with an emphasis on the mechanisms leading to damage creation and phase transformations. We report typical results obtained for ceramics irradiated with ions in a broad energy range (from KeV to GeV) in order to explore both nuclear collision and electronic excitation regimes. These results were recorded by combining ion-beam techniques (RBS, channeling, data analyzed with the McChasy Monte-Carlo code) with other advanced techniques which probe the sample at various spatial scales (XRD, TEM, Raman).