The use of subcritical aqueous homogenous reactors driven by accelerators presents an attractive alternative for producing99Mo. In this method, the medical isotope production system itself is used to extract99Mo or other radioisotopes so that there is no need to irradiate common targets. In addition, it can operate at much lower power compared to a traditional reactor to produce the same amount of99Mo by irradiating targets. In this study, the neutronic performance and99Mo,89Sr, and131I production capacity of a subcritical aqueous homogenous reactor fueled with low-enriched uranyl nitrate was evaluated using the MCNPX code. A proton accelerator with a maximum 30-MeV accelerating power was used to run the subcritical core. The computational results indicate a good potential for the modeled system to produce the radioisotopes under completely safe conditions because of the high negative reactivity coefficients of the modeled core. The results show that application of an optimized beam window material can increase the fission power of the aqueous nitrate fuel up to 80%. This accelerator-based procedure using low enriched uranium nitrate fuel to produce radioisotopes presents a potentially competitive alternative in comparison with the reactor-based or other accelerator-based methods. This system produces ~1,500 Ci/wk (~325 6-day Ci) of99Mo at the end of a cycle.
Gholamzadeh, Z., Feghhi, S. A. H., Mirvakili, S. M., Joze-Vaziri, A., & Alizadeh, M. (2015). Computational investigation of99Mo,89Sr, and131I production rates in a subcritical UO2(NO3)2aqueous solution reactor driven by a 30-MeV proton accelerator. Nuclear Engineering and Technology, 47(7), 875–883. https://doi.org/10.1016/j.net.2015.08.004