Category Archives: Advanced separation techniques for nuclear fuel reprocessing and radioactive waste treatment

Transmutation fuel development

Because minor actinide bearing fuel is still a new field, a tremendous amount of excellent research has been accomplished to date [7]. It appears that the greatest emphasis has been placed on heterogeneous target fuel concepts with a high content of minor actinides only (i. e., no plutonium). This trend may have been driven by the desire to set the […]

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Biosorption and recovery

The biosorption process is designed to remove metallic species, especially those originating from the nuclear reaction process in power plants, for further processing and recovery. The majority of these are the products of nuclear fission of uranium to form lighter elements. During the first several hundred years after the fuel is removed from a reactor, fission products are considered the […]

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Multiphase formation in solvent extraction

In the operation of solvent extraction systems in the laboratory, where new reagents and processes are typically developed, conditions are typically maintained in a moderately idealized state. In particular, the effects of “loading”, i. e., contacting aqueous solutions containing high concentrations of metal ions with extractant solutions targeting those metal ions, are typically not investigated until an advanced stage of […]

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Centrifugal contactors

Centrifugal contactors are classed as stage-wise or equilibrium contactors because, like mixer-settlers, they manifest a step concentration profile as the aqueous and solvent phases pass from stage to stage. Also, like mixer- settlers, they consist of mixing and phase separation compartments. However, phase separation occurs under the action of centrifugal, rather than gravitational forces, which leads to more compact processing […]

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Partitioning step

The organic phase exiting the codecontamination cycle contains most of the actinides (U, Pu, and Np) initially present in the dissolved fuel. Some resid­ual fission products, notably Tc and Zr, are also present in the organic phase. The next step of the process (referring to Fig. 6.2) is partitioning, which involves the selective stripping of Pu and U from the […]

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UREX+3

The process was demonstrated in 2003 and 2007. Different separations modules were tested for the recovery of Cs/Sr and Am/Cm products. In 2003, CCD-PEG and Cyanex 301 were tested. In 2007, FPEX and TALSPEAK were tested. In addition, in 2003, Tc was separated from uranium by selective stripping while in 2007 an ion exchange resin was used to make the […]

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Solidification of low-level raffinate of UNEX process

To assess the possibility of solidification of the low-level raffinate, with the aim of its near-surface storage, the traditional LLW cementing technique was tested. Test results indicated that, during cementing, the solidification process proceeded uniformly, and the cement blocks produced did not crack on discharge from the mold or in subsequent storage. Although the cement bulk per volume of raffinate […]

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Development of highly selective compounds for solvent extraction processes: partitioning and transmutation of long-lived radionuclides from spent nuclear fuels

C. HILL, CEA, France Abstract: This chapter discusses the methodology deployed in the European partitioning strategy to design highly selective extractants for long-lived radionuclide separation: calix[4]arenes for caesium, malonamides for the co-extraction of trivalent minor actinides (Am, Cm) and lanthanides (Ln(III)), and nitrogen-donor ligands, such as bis-triazinyl-pyridines, for the separation of trivalent minor actinides from Ln(III).

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Future trends in solid-phase extraction technology for nuclear fuel reprocessing applications

Advances in the field of solid-phase extraction, along with substantial improvements in automated control systems and on-line monitoring, suggest that the technology merits further consideration for nuclear fuel reprocess­ing applications. The technology is probably more suited to MA and Ln separations subsequent to the removal of U and Pu by other means, or for polishing applications in any number of […]

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