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Development Of A Glass-Encapsulated Ceramic Wasteform For The Immobilization Of Chloride-Containing ILW

Published online by Cambridge University Press:  01 February 2011

Brian L. Metcalfe
Affiliation:
Materials Science Research Division, Atomic Weapons Establishment, Aldermaston, Berkshire, RG7 4PR, U.K.
Shirley K. Fong
Affiliation:
Materials Science Research Division, Atomic Weapons Establishment, Aldermaston, Berkshire, RG7 4PR, U.K.
Ian W. Donald
Affiliation:
Materials Science Research Division, Atomic Weapons Establishment, Aldermaston, Berkshire, RG7 4PR, U.K.
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Abstract

Pyrochemical reprocessing of plutonium generates several ILW waste-streams and a simple process has been developed at AWE to immobilize the chloride and actinide ions present in one of these waste-streams (Type 1) by calcining the waste with calcium phosphate. We have now investigated the possibility of using this process as the basis for treating a more complex waste-stream (Type 2) and have determined that with some minor modification the original process can effectively immobilize the greater range of cations present in Type 2 waste to again produce a free-flowing non-hygroscopic powder. Weight for weight replacement of the Type 1 waste by Type 2 produced a powder which was approximately 20% deficient in PO43- when compared with stoichiometric powder. Addition of phosphorus pentoxide to the simulant waste/calcium phosphate powder mixture prior to calcination to produce stoichiometric powder significantly improved the chloride ion uptake. In order to comply with safety requirements it is necessary to convert the free-flowing powder into a monolithic wasteform suitable for long term storage. Conversion of the powder to a monolithic wasteform by sintering using a sodium aluminophosphate glass as a binder has been investigated and has proved successful, but to achieve high densities it has been necessary to cold press the samples prior to sintering.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

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