Pyroprocessing

Another, more modern, route of processing the yellow cake is shown in Figure 5.38, accomplishes the production of enriched uranium oxide entirely by pyroprocessing. Thus, uranium is finally obtained in three forms metallic uranium, enriched uranium dioxide, and natural uranium dioxide. As the flowsheet shows, and as briefly described herein, these are essentially the products of hydro and pyro-based processing schemes. 

Pyroprocessing, of Portland cement raw material, 5 488—489 Pyroredox process, 19 678 Pyrosulfuryl chloride, 23 641, 645, 647, 649 Pyrosultones, decomposition of, 23 527 Pyrotechnics... 

Recent studies on the electrochemical behavior of plutonium in molten salts have mainly been performed in LiCl— KCl based melts. The electrorefining step in a pyroprocessing procedure for the recycling of nuclear fuel from the Integral Fast Reactor (IFR) Program has been... 

Geopolymers are another type of intermediate products that lie between cements and ceramics [7]. A geopolymer is made by pyroprocessing naturally occurring kaolin (alumina-rich clay) into metakaolin. This metakaolin is then reacted with an alkali hydroxide or sodium silicate to yield a rock-Uke hard mass. Thus, a chemical reaction, which is not fully understood, is employed to produce a hard ceramic-Uke product. Though this product is produced like cement, its properties are more like a sintered ceramic. It is dense and hard like a rock. 

Improvement of the energy efficiency in the pyroprocessing is reached by increasing the fuel efficiency of the kiln for example by replacing the wet kilns with preheater and precalciner systems, resulting in significant reduction of the CO2 emissions. 

Waste fuels are in the pyroprocess used practically in each Slovak cement works. Good results were gained during burning the car tires and organic waste. 

P6. Pierce, R. D., and L. Burris, Jr. Pyroprocessing of Reactor Fuels, in Selected Review of Reactor Technology, Report TID-8540, 1964, chap. 8. 

Fig. 8.1 Example of an industrial plant (pyroprocessing of minerals) heavily polluted with airborne particulate solids...

Fig. 7.2 Process diagram of powder metallurgy (courtesy of MPIF, Princeton, NJ, USA) Fig. 8.1 Example of an industrial plant (pyroprocessing of minerals) heavily polluted with airborne particulate solids Fig. 8.2 a) Enlarged view of the interior of a filter mat with particles sticking to the fiber surfaces, b) Detail of a dust laden fiber from (a) showing how particles extend into the gas stream [B.71]...

Strength Early Strength Standard Strength Pyroprocess Type Raw Material Moisture Content, % w/w... 

All first generation fast breeder reactors have been shutdown or decommissioned with only the fast flux Test facility remaining in a standby condition awaiting final decommissioning. Fast breeder reactor development activities have been terminated with limited technology development in transmutation and pyroprocessing. 

A. Phase changes and phase concentrations at various stages in the pyroprocessing system (including buildups, rings, coatings, and clinker-refractory reactions)... 

Environmentally friendly KALIMER has extremely low probability and amount of accidental radioactivity releases. The KALIMER core is loaded with metallic fuel which can be recycled through pyroprocessing. Recycling of transuranic elements by this process would avoid the expense and potential long-term risk of their disposal in a geological repository, and would provide increased proliferation resistance. The high thermal efficiency of KALIMER also improves the economics and makes it possible to discharge reduced amount of heat to the environment. 

A variation of the PUREX process is being proposed by the US Department of Energy as a possible alternative partitioning scheme for the transmutation of wastes. This aqueous process called UREX, only removes uranium from spent commercial LWR fuel and leaves plutonium in the HLW stream with the other minor actinides and fission products. Nonaqueous pyroprocessing, a variation of the ANL electrorefining process, is then proposed to be used to separate both the plutonium and minor actinides so that they can be transmuted in an ADS. For further information related to potential modifications of this process for other accelerator transmutation of waste applications, see ANL-99/15 (1999). 

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