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Undeclared uranium hitches a ride on cobalt exports from Congo, study says
Philippe (left) and Manzuk quantified the amount of uranium that has been exported from the DRC in cobalt shipments or left behind in the environment. (Photo: Joel Hallberg/UW–Madison)
Researchers at the University of Wisconsin–Madison and Princeton University have published a study in Nature Communications that calls attention to a blind spot in nuclear nonproliferation: The Democratic Republic of the Congo (DRC) has exported thousands of metric tons of uranium, and there is no accounting for where it has gone.
In partnership with Lighthouse Reports and the Financial Times, UW–Madison nuclear engineering professor and nuclear security expert Sébastien Philippe and Ryan Manzuk, a geologist and research fellow in Philippe’s group and at Princeton, conducted the study using countrywide mineralization and geochemical data.
Tsuguyuki Kobayashi
Nuclear Technology | Volume 177 | Number 2 | February 2012 | Pages 231-244
Technical Paper | Reprocessing | doi.org/10.13182/NT12-A13368
Articles are hosted by Taylor and Francis Online.
A simple procedure to simulate the important kinetic features of counter-current processes in pulsed columns has been developed. The overall mass transfer coefficient was simplified to be constant along the column, and the stripping of Pu4+ by hydroxylamine is assumed to be instantaneous to avoid complex reaction rate calculations. The number of calculation cells can be determined by making calculations with an increasing number of cells until its influence becomes small enough. The validity of these simplifications was confirmed by comparing the calculation results with a wide range of measured data from extraction and stripping as well as Pu partition tests with laboratory, engineering, and pilot scale columns. This procedure is intended for use in a conceptual design study of a future fast breeder reactor (FBR) reprocessing plant. An example of its application in a flow sheet calculation was demonstrated, where a coextraction process of U and Pu was simulated to find the conditions to obtain a solution with Pu/(U + Pu) ratio being 30% from a typical feed of FBR spent fuel solution.