Hot-pressed phosphate glass–ceramic matrix composites containing calcium phosphate particles for nuclear waste encapsulation
- 169 Downloads
Sodium aluminium phosphate (NaAlP) glass–ceramic composites were produced as potential wasteforms for the immobilization of special categories of halide-containing radioactive waste. Sintering conditions for encapsulating a simulated waste (a calcinated mixture of calcium phosphate host and various oxides) in the cold-pressed NaAlP glass–ceramic were first determined and the results were compared with similar samples prepared by hot pressing. In both cases, the conditions aimed to provide a very high-density material, via as low production temperatures as possible, in conjunction with a high waste loading (75 wt.% simulated waste to 25 wt.% glass). It was found that by hot pressing and using a NaAlP glass–ceramic containing 2 mol% B2O3, significantly lower temperatures could be employed compared to the cold pressing and sintering route. The lowest temperature at which a sufficiently dense hot-pressed product was achieved (86% theoretical density), that exhibited mechanical properties similar to those of borosilicate glass (e.g. Young’s modulus 67 ± 2 GPa), was 550 °C. This processing temperature is considerably lower than values reported in the literature for similar systems. As such, hot pressing can be considered as a convenient technique for the fabrication of this type of composite for waste encapsulation.
KeywordsB2O3 Phosphate Glass Glass Powder Waste Form Chemical Durability
This work was carried out as part of the TSEC programme KNOO and as such we are grateful to the EPSRC for funding under grant EP/C549465/1. We are particularly grateful to Brian Metcalf, Ian Donald and Shirley Fong of AWE Aldermaston (UK) for invaluable discussions and who suggested this study.
- 1.Ojovan MI, Lee WE (2005) An introduction to nuclear waste immobilisation. Elsevier Ltd., Oxford, UKGoogle Scholar
- 3.Metcalfe BL, Fong SK, Donald IW (2004) In: Oversby VM, Werme LO (eds) Materials research society symposium proceedings, vol 807. Warrendale, PA, pp 255–260Google Scholar
- 6.Donald IW (2004) Discovery: Sci Technol J AWE 9:2Google Scholar
- 11.Boccaccini AR, Berthier T, Seglem S (2007) Ceram Int 33:1231Google Scholar
- 12.Saewong P (1998) PhD Thesis, Department of Materials, Imperial College, London, pp 45–47Google Scholar
- 13.Morton RD (1961) Norsk geologisk tidsskrift 41:223Google Scholar