Uranium, separation using supported

Opportunities remain to develop new or improved separation chemistries, and the engineered solid-phase materials that utilize them, in order to support radioanalyti-cal needs. Selectivity remains a key issue in order to support isolation of particular elements or groups of elements from complex sample matrixes. Selectivity to support determination of TRU actinides in the presence of large excesses of uranium is often required. The engineered form is also significant, as it must enable the separation chemistry to work while providing a robust material that can be used over and over again. 

Although physics and chemistry were responsible for the conceptual framework overall, radiochemistry defined the experimental approach and provided much of the initial data. The neutron sources then in use (usually radium or radon [a source of alpha particles] mixed with powdered beryllium) were weak, with the result that the new beta activities were not much stronger than the natural radioactivity of uranium and its decay products. In 1934, the Rome group chemically separated the new activities from uranium by co-precipitating them with manganese and rhenium compounds (both transition metals), which supported the notion that these were... 

Rathore, N.S., Sonawane, J.V., Gupta, S.K., Pabby, A.K., Venugopalan, A.K., Changrani, R.D., and Dey, P.K., Separation of uranium and plutonium from aqueous acidic wastes using a hollow fiber supported liquid membrane. Sep. Sci. Tech., 2004, 39 1295-1319. 

The plutonium produced by neutronic reactors using 20 natural uranium to support the reaction is useful for many purposes, but it has one outstanding advantage over, for example, the use of U , as it exists in natural uranium. As plutonium is a different element from uranium it can be chemically removed from the irradiated 25 natural uranium, and because of that fact can be obtained in substantially pure form and in high concentrations whereas U can only be obtained in high concentration or substantially pure form (as far as presently known) by the much more difficult process of isotope 30 separation. U 3s of high concentration, however, has been used to sustain a neutronic reaction. 

In our laboratories, research and development studies have been conducted on the separation of uranium and various lanthanides by common extractants (carriers) and of actinides by crown ether carriers using different types of liquid membrane systems. Also our studies have been directed toward determining optimal support systems for supported liquid membranes (SLM) which may offer improved flux... 

The GT-MHR reactor design can accommodate alternative fuel cycles if supported by external infrastructure. A fuel cycle utilizing recycled water reactor plutonium can be accommodated, and will be effectively demonstrated by the GT-MHR plutonium consumption project in the Russian Federation. Thorium can be used as an alternative to natural uranium in the fertile particles. If reprocessing is supported in the future, fissile particles can incorporate recycled U from thorium fertile particles to reduce the separative work required to produce fissile particles. 

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