Separation radionuclides

T0007 ADTECHS Corporation, Radionuclide Separation Process (RASEP)... 

ADTECHS Corporation (ADTECHS) has developed the radionuclides separation (RASEP) process for the removal and stabilization of radionuclides from liquid waste streams. The process uses filtration, selective adsorption, and electrodeposition fixation followed by cement sohdifi-cation. According to the vendor, the technology is commercially available. 

Principal radionuclide Precursor of principal radionuclides Separation schemes... 

Choppin, G.R. Morgenstem, A. Radionuclide separations in radioactive waste disposal, J. Radio anal. Nucl. Chem. 243 (2000)45-51. 

Madic, C., Bourges, J., Dozol, J.F. 1994. Brief overview of the long-lived radionuclide separation processes developed in France in connection with the SPIN program. International Conference on Accelerator-Driven Transmutation Technologies and Applications, July, Las Vegas, NV. 

CCD and its brominated analog (Br-COSAN) are very widely studied as potential components of extraction mixtures for radionuclide separation. These compounds were proposed for extraction more than 30 years ago,17 and already in the first publications, polyethylene glycols (PEGs) were used for simultaneous extraction of cesium and strontium. An excellent review of extraction by carborane compounds was recently published 18 so, in this paper, mainly works published after 2003 and not included in the previous review will be discussed. 

Fjeld, R. A., Roane, J. E., Leyba, J. D., Paulenova, A., and DeVol, T. A., Sequential and simultaneous radionuclide separation-measurement with flow-cell radiation detection, ACSSymp. Ser., 868, 105-119, 2004. 

Dietz, M. L., Recent progress in the development of extraction chromatographic methods for radionuclide separation and preconcentration. In Radioanalytical Methods at the Frontier of Interdisciplinary Science, eds. C. Laue and K. Nash, American Chemical Society, Washington, DC, 2004, pp. 161-176. 

Groundwater is the chief medium facilitating radionuclide separation, and, as such, the various concentrations vary over a wide range of values. For instance, U has been measured at concentrations from 10 ppb to hundreds of ppm, a range of over eight orders of magnitude. In contrast, all Th isotopes are always at very low concentrations in water. 

Choppin, G.R. andMorgenstem, A., Radionuclide Separations in Radioactive Waste Disposal. 7. Radioanal. Nucl. Chem., 2000,243 45-51. 

The recoil energy is not the only factor that controls the degree to which the new radionuclide separates itself from the original matrix, and some of the recoil energy it is dissipated by other mechanisms. Moreover, the recoiling atom may return to its original molecule or crystal site, especially when the product remains the same element as its antecedent, as in an (n,y) reaction or after an internal transition. The product nuclide and its antecedent nuclides may rapidly interchange to reduce the specific activity of the product. 

Carrier addition is widely used, not only for yield determination, but because the added mass avoids problems of radiocolloidal behavior. Other advantages of added carrier are the ability to use precipitation for radionuclide separation and purification, and avoidance of unintended coprecipitation during scavenging. When carrier is not added because no stable isotope is available or the counting source must be very thin, radionuclide deposition on container walls or on suspended solids must be avoided by applying the techniques discussed in Section 4.4, notably use of nonisotopic carrier or low pH. 

Lanthanide polyoxometallates have potential uses for radionuclide separation and for nuclear... 

Selective resins for radionuclide separations are commercially available in different forms, such as cartridges, packed columns, beads and disks. Moreover, there are available various pore size ranges. 

The DAC values relate to one of two modes of exposure either external submersion or the internal committed dose equivalents resulting from inhalation of radioactive materials. Derived air concentrations based upon submersion are for immersion in a semi-infinite cloud of uniform concentration and apply to each radionuclide separately. 

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