RESUMO
99Mo, the parent of the widely used medical isotope 99mTc, is currently produced by irradiation of enriched uranium in nuclear reactors. The supply of this isotope is encumbered by the aging of these reactors and concerns about international transportation and nuclear proliferation. Methods: We report results for the production of 99Mo from the accelerator-driven subcritical fission of an aqueous solution containing low enriched uranium. The predominately fast neutrons generated by impinging high-energy electrons onto a tantalum convertor are moderated to thermal energies to increase fission processes. The separation, recovery, and purification of 99Mo were demonstrated using a recycled uranyl sulfate solution. Conclusion: The 99Mo yield and purity were found to be unaffected by reuse of the previously irradiated and processed uranyl sulfate solution. Results from a 51.8-GBq 99Mo production run are presented.
Assuntos
Molibdênio/química , Fissão Nuclear , Aceleradores de Partículas/instrumentação , Radioisótopos/química , Geradores de Radionuclídeos/instrumentação , Compostos de Urânio/química , Desenho de Equipamento , Análise de Falha de Equipamento , Marcação por Isótopo/instrumentação , Marcação por Isótopo/métodos , Teste de Materiais , Nêutrons , Reatores Nucleares , Projetos Piloto , Doses de Radiação , Compostos Radiofarmacêuticos/síntese química , Compostos de Urânio/efeitos da radiaçãoRESUMO
Molybdenum-99 (Mo-99), generated from the fission of Uranium-235 (U-235), is the radioactive parent of the most widely used medical isotope, technetium-99m (Tc-99m). An efficient, robust, low-pressure process is developed for recovering Mo-99 from uranyl sulfate solutions. The minimum column volume and the maximum column length for required yield, pressure limit, and loading time are determined using a new graphical method. The method is based on dimensionless groups and intrinsic adsorption and diffusion parameters, which are estimated using a small number of experiments and simulations. The design is tested with bench-scale experiments with titania columns. The results show a high capture yield and a high stripping yield (95±5%). The design can be adapted to changes in design constraints or the variations in feed concentration, feed volume, or material properties. The graph shows clearly how the column utilization is affected by the required yield, loading time, and pressure limit. The cost effectiveness of various sorbent candidates can be evaluated based on the intrinsic parameters. This method can be used more generally for designing other capture chromatography processes.
