Nuclear Power
providing a sufficiently stable matrix to retain the waste during impact (displaying exceptional performance compared to a grouted drum). Te silicones showed no significant generation of gas under irradiation, and progressively stiffened towards a glass material with increased doses, as anticipated. And importantly, heat generation on curing was found to be insignificant compared to large scale grout pours or epoxy resins. Te trials to date have shown silicone polymers to perform well as waste encapsulation materials for UK ILW, in particular where there are reactive materials present. Work is now on-going to evaluate the
hardening process at higher doses, and further work is planned by Babcock in conjunction with site licence companies and the NDA to establish silicones as a desirable material for orphan waste encapsulation.
Conclusion Te various polymeric material investigations being undertaken by Babcock are currently at the forefront of this area of research, to identify optimum methods of encapsulation for a range of waste streams that are unsuitable for other approaches such as cementation. ●
Dr Steven Black is a technical and assurance services manager with Babcock International Group’s nuclear business, headquartered in Wigmore Street, London, UK. He is based at Westlakes Science & Technology Park, Cumbria, UK.
www.babcock.co.uk
Fig. 5. Section of Windscale liner containing Pile 1 waste simulant including graphite, metal fines, fuel cartridges and isotope cartridges encapsulated in epoxy resin.
Fig. 6. Trials have been carried out to establish the suitability of silicones for encapsulation of orphan waste streams. Shown: sectioned silicone waste drum following impact testing.
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