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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.
A. Serikov, U. Fischer, L. Mercatali, P. Baeten, G. Vittiglio
Nuclear Technology | Volume 168 | Number 3 | December 2009 | Pages 877-887
Shielding | Special Issue on the 11th International Conference on Radiation Shielding and the 15th Topical Meeting of the Radiation Protection and Shielding Division (PART 3) / Radiation Protection | doi.org/10.13182/NT09-A9322
Articles are hosted by Taylor and Francis Online.
The VENUS-F facility of the GUINEVERE project must satisfy the nuclear safety criteria required by the licensing regulations of the Belgian authority. For this reason, radiation shielding analyses were performed at Forschungszentrum Karlsruhe (FZK) in the course of nuclear safety assessments in support of the GUINEVERE project. The Monte Carlo (MC) MCNP5 model was developed in accordance with the current design of the VENUS-F fast lead reactor. The reactor was assumed to operate on 500-W fission power, which is called zero power, with accelerator-driven system (ADS)-related experimental aims. The MC variance reduction techniques, such as particle splitting, Russian roulette, weight windows, and point detectors, were applied. To speed up the MCNP calculations, the advantages of message-passing interface parallel computations on FZK's CampusGrid Linux Cluster were employed. The MCNP track-length estimations, point detectors, and the mesh tally superimposed over the GUINVERE geometry were used in dose rate calculations. The neutron and photon maps of dose equivalent rate were produced in places of possible personnel access inside the reactor control room and on the accelerator room's floor. To obtain the dose equivalent, the neutron and photon fluences were converted by means of ICRP-77 and ANSI/ANS-6.1.1-1977 conversion factors, respectively. The contributions of the D-D and D-T fusion neutron sources to the dose rate fields were estimated. Activation analyses of the lead core and building materials were performed by the FISPACT-2005 inventory code with the EAF-2005 library to manage the radioactive materials after the series of ADS experiments in the GUINEVERE project. The activity density and shutdown contact dose rate have been calculated. The effect of the impurities in lead on its radioactivity after the VENUS-F campaign was examined.