XAS and EELS analysis on ion irradiated iron phosphate glass

Abstract

Iron phosphate glass (IPG) is considered as a suitable alternate matrix for the immobilization of high level nuclear waste from fast reactors. Ion irradiation on IPG, induces changes in the charge state of the atomic species in IPG. When the metal ions (the glass formers or the glass stabilizers) change their charge state, the glassy nature is disturbed extensively. The changes in the charge state of Fe atoms in IPG, were characterized using XAS and EEL spectroscopy, in the present work. The analysis of core level spectra (XAS and EELS) showed that the concentration of Fe2+, on the whole, has increased and Fe3+ has reduced in the specimen upon ion irradiation. Since the Fe atom with charge state +2 exists only in glass phase of Fe3(P2O7)2, the rise in the population of Fe2+ implies that the glass phase of Fe3(P2O7)2 has increased in the glass matrix. The rise in the population of Fe2+ increases the viscosity of IPG, which in turn increases the glass forming ability.