Evolution of nuclear glass structure under alpha-irradiation

The French nuclear glass is intended for the long-time storage of high-leve l nuclear wastes. The disintegration of radioelements induces modifications of the glass structure which could deteriorate the efficiency of the confi nement. We have focused our study on the effects from x-decay processes (al pha particles and recoil nuclei) in two simplified alumino-borosilicate gla sses which contain the major constituents of French light water containment glass. The alpha-decay processes were simulated by external irradiations a t room temperature with 1.0 MeV He+ or 2.1 MeV Kr3+ so as to exhibit the di fferences between effects produced by ct particles and by recoil nuclei. Mi cro-Raman spectroscopy has been used to investigate the evolution of the gl ass under rx-irradiation at a microstructural level through modifications o f the network vibration bands. We have used nanoindentation to show the cha nges in macroscopic properties and the Molecular Dynamics (MD) method to ob serve the effect of a cascade at the atomic scale. (C) 2000 Elsevier Scienc e B.V. All rights reserved.