Processing Ceramics for Radioactive Waste Immobilisation

Abstract

The basic principles of incorporating high level radioactive waste into glasses, ceramics and glass composite materials (GCMs) are described. Current UK technology uses glass wasteforms for the products of reprocessing while some waste streams may be incorporated in ceramics and difficult or legacy wastes will require the development of other wasteforms many of which will be GCMs. Processingproperty- structure relations in novel wasteforms are described including the use of self-sustaining reactions to produce a composite ceramic wasteform based on TiC and Al2O3 from irradiated graphite and development of a GCM wasteform for immobilising spent zeolite sand filters.

Tailored Perovskite Waste Forms for Plutonium Trapping

“…One solution to plutonium storage is its incorporation into ceramic materials that are known on the basis of mineral analogues to be capable of retaining radionuclides in the long term. ,− Ceramic materials have the additional advantage of tenaciously retaining an array of cations with widely varying ionic radii and valences within their lattices. , For immobilization of radiolanthanides and actinides, single-phase and stable polyphase ceramics have been considered as tailor-made hosts and are important alternatives to the use of glass matrices for containment. These ceramic materials include zirconolite (CaZrTi 2 O 7 ), hollandite (BaAl 2 Ti 6 O 16 ), monazite (LnPO 4 ; Ln = La to Gd), pyrochlore (A 2 B 2 O 7 ), and members of the perovskite family (CaTiO 3 ), as well as many others. − …”

Glassy Wasteforms for Nuclear Waste Immobilization

“…Vitreous waste forms represent one end of the spectrum of the HLW waste forms shown in Table I. [2,3] At the other end of the spectrum shown in Table I, the use of predominantly crystalline ceramic wasteforms (ceramication) has also been proposed including singlephase ceramics such as zircon to accommodate a limited range of active species such as Pu and multiphase systems such as Synroc to accommodate a broader range of active species. [4] To date, these systems have not been used extensively to immobilize active waste.…”