Radiation tolerance of iron phosphate: A study of amorphous and crystalline structures

Iron phosphate has been proposed as a candidate material for the encapsulation of nuclear waste. We studied amorphous and crystalline structures of Fe2+Fe23+(P2O7)(2) and Fe3+(PO3)(3). Amorphous Fe-4(3+)(P2O7)(3), and two structures comparable with experimentally produced iron phosphate glass (IPG): 40 mol% Fe2O3 and 60 mol% P2O5, with 4% and 17% Fe2+ ion concentrations were also investigated. A series of constant volume molecular dynamics (MD) simulations of radiation cascades at 4 keV were performed. In the crystal structures, the cascades caused local amorphisation. For the glass structures, the cascades generally produced a rearrangement of atoms but did not significantly alter the overall atomic co-ordination or the ring statistics. Our work suggests that IPG, especially that with a low Fe2+ ion content, is resistant to radiation in the nuclear stopping regime. However, the crystalline material with its transition to a radiation tolerant glassy form, could also be a potential candidate for the containment of nuclear waste. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.