COMPUTATIONAL INVESTIGATION OF Mo-99, Sr-89, AND I-131 PRODUCTION RATES IN A SUBCRITICAL UO2(NO3)(2) AQUEOUS SOLUTION REACTOR DRIVEN BY A 30-MEV PROTON ACCELERATOR

摘要

The use of subcritical aqueous homogenous reactors driven by accelerators presents an attractive alternative for producing Mo-99. In this method, the medical isotope production system itself is used to extract Mo-99 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 of Mo-99 by irradiating targets. In this study, the neutronic performance and Mo-99, Sr-89, and I-131 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 similar to 1,500 Ci/wk (similar to 325 6-day Ci) of Mo-99 at the end of a cycle. Copyright (C) 2015, Published by Elsevier Korea LLC on behalf of Korean Nuclear Society.