COMPOSITION-STRUCTURE RELATIONSHIPS IN SIMPLIFIED NUCLEAR WASTE GLASSES. PT.1. MIXED ALKALI BOROSILICATE GLASSES

A systematic molecular dynamics (MD) study of the composition-structure relationships in sodium lithium borosilicate glasses is presented. The results were compared with published laboratory glass data. These glasses are of importance to the UK nuclear waste vitrification programme where knowledge of the glass structure can improve the understanding of long-term glass properties and waste element solubility. The MD-simulated glasses produced showed close agreement with laboratory glasses for bond lengths, atom coordination and bond angles of all species. The change in coordination of boron was accurately reproduced over a wide compositional range without the use of a three-body potential for the O-B-O angle. The change in the polymerisation and mixing of the silicate and borate networks with composition in the MD-simulated glasses agreed well with that seen in laboratory glasses.