The development of glass compositions for the vitrification of ion exchange resin wastes from the nuclear industry

• Main Author: McGann, O. J.
• Other Authors: Hyatt, N. C. ; Bingham, P. B.
• Published: University of Sheffield 2014
• Subjects: 620
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595238

Ion exchange resin (IEX) wastes from the nuclear power generation are a growing problem faced by the nuclear industry both in the UK and abroad. Vitrification of these wastes offers a route for their disposal by which these wastes can be immobilised in a durable waste-form. However, vitrification of these wastes possessed three major problems due to the anionic content of the waste, the organic content of the waste and the volatile radionuclides present in the waste which are problematic for vitrification. In order to identify routes by which these wastes may be successfully vitrified, systematic development experiments were carried out on three glass systems, an alkali borosilicate glass system, an alkali alkaline-earth glass system and a calcium silicate glass system. These development experiments identified a number of novel glass compositions which possessed improved properties in terms of reduced melting temperatures, increased capacities for sulphur species, increased capacities for reduction, amongst other improvements to physical properties. These improvements were attributed to changes to the glass forming network due to additive species. Glass compositions were waste-loaded with simulant IEX waste. ZnO containing alkali alkaline-earth silicate glass waste-forms demonstrated high levels of sulphur retention and near total caesium retention. These results were attributed to the physical properties of the novel glass compositions. Developed waste-forms were demonstrated to possess superior aqueous durability and radiation stability due to low alkali content and the presence of Fe in their composition. A mechanism was identified by which Fe acted to prevent the accumulation of ?-radiation induced defects in the waste-forms. ZnO-containing alkali alkaline-earth silicate glass compositions were shown to have a low melting temperature, high density, increased capacity for anionic species and the ability to achieve high Cs retentions.