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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.
N. Zweibaum, Z. Guo, J. C. Kendrick, P. F. Peterson
Nuclear Technology | Volume 196 | Number 3 | December 2016 | Pages 641-660
Technical Paper | doi.org/10.13182/NT16-15
Articles are hosted by Taylor and Francis Online.
The capability to validate integral transient response models is a key issue for licensing new reactor designs. The Compact Integral Effects Test (CIET 1.0) facility reproduces the thermal-hydraulic response of fluoride salt–cooled high-temperature reactors (FHRs) under forced- and natural-circulation operation. CIET 1.0 provides validating data to confirm the predicted performance of the direct reactor auxiliary cooling system, used for natural-circulation–driven decay heat removal in FHRs, under a set of reference licensing basis events. CIET 1.0 uses a simulant fluid, DOWTHERM A oil, which, at relatively low temperatures (50°C to 120°C), matches the Prandtl, Reynolds, and Grashof numbers of the major liquid salts simultaneously, at 50% geometric scale and heater power under 2% of prototypical conditions. CIET 1.0 has been designed, fabricated, filled with DOWTHERM A oil, and operated. Isothermal pressure drop tests were completed, with extensive pressure data collection to determine friction losses in the system. The project then entered a phase of heated tests, from parasitic heat loss tests to more complex feedback control tests and natural-circulation experiments, with the ultimate goal of validating best-estimate FHR models using RELAP5-3D and the novel one-dimensional FHR Advanced Natural Circulation Analysis (FANCY) code. This paper introduces the scaling strategy, design, and fabrication aspects, and start-up testing results from CIET 1.0. The CIET 1.0 model in RELAP5-3D and FANCY is detailed, and verification and validation efforts are presented. For various heat input levels and temperature boundary conditions, mass flow rates are compared between RELAP5-3D and FANCY results, analytical solutions when available, and experimental data, for both single and coupled natural-circulation loops. The study shows that both RELAP5-3D and FANCY provide excellent predictions of steady-state natural circulation in CIET 1.0, with mass flow rates within 13% of experimental data, suggesting that both codes are good candidates for design and licensing of FHR technology.
