SYNROC immobilization

According to researchers, furnaces for ceramic immobilization processes typically cost less than 1000 (D16044B, p. 155). According to the researchers, the SYNROC approach is only cost effective for large-scale applications (a large-scale application is assumed to produce 30-cm-diameter disks, each weighing approximately 30 kg). Cold press applications of the SYNROC process are more cost effective (D160429, pp. 255-256). No cost information is available for the Ceramification and SMITE processes. 

Lashtchenova, T. N. Stefanovsky, S. V. 1998a. Immobilization of incinerator ash in Synroc-glass material. In Proceedings of the ITS International Conference on Incineration Thermal Treatment Technologies, Salt Lake City, 603-607. 

Vance, E. R., Carter, M. L., Day, R. A., Begg, B. D., Hart, K. P. Jostsons, A. 1996b. Synroc and Synroc-glass composite waste forms for Hanford HLW immobilization. In Proceedings of the International Topical Meeting on Nuclear and Hazardous Waste Management SPECTRUM 96. American Nuclear Society, Inc. La Grange Park, 2027-2031. 

Based on the leaching data [40,69,83] as well as data on radiation resistance of fast neutron irradiated [84-85] and actinide-doped Synrocs [86-88], as well as individual synthetic phases and their natural analogues study [14-18,89-91] zirconolite- and pyrochlore-based ceramics have been proposed for immobilization of excess plutonium and the other actinides. Moreover, additional phases, which were not part of the Synroc formulation, have been considered because of their chemical durability and radiation resistance (e.g., murataite, zircon, garnet, monazite, britholite). Of particular interest are the zirconate pyrochlores, many of which are extremely radiation resistant [8,92]. Zirconolite-based ceramics. Zirconolite, ideally CaZrTi207, is a major actinide host phase in the Synroc-type ceramics. Study of natural and synthetic samples... 

A second-generation immobilization material, synroc, is in development. This synthetic rock, based on mixed titanate phases such as zirconolite, hollandite, or perovskite, incorporates the HLW elements into its crystal structure, yielding excellent chemical stability. Synroc features leach rates more than an order of magnitude lower than borosilicate glass. 

In Russia, besides the Radium Institute, research on the synthesis of crystal ceramics is carried out mainly for the immobilization of actinide-containing wastes at the RPA Radon , the Bochvar VNIINM, and some other organizations. The research activities are at the stage of laboratory experiments with a use of simulators of actinides. As a rule, ceramics of the titanate composition of the SYNROC type are synthesized, or some other phases (for example, monazite). Two methods of synthesis used are the cold crucible or hot pressing. 

The SYNROC process (Ringwood 1978) for treating nuclear wastes is another example of immobilization. Certain chemicals are added to the nuclear waste, which is then sintered and produces a mixture of minerals (a SYNthetic ROCk) that are known to be stable under the range of geological conditions that can be expected at the disposal site. 

Freudenbergife. Na2Al2Ti60i5. A SYNROC (q.V.) phase, for immobilizing sodium. 

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