Abstract
Aqueous Homogeneous Reactors (AHRs) or simply solution reactors present nowadays a promising alternative to produce medical isotopes, especially 99Mo. The AHR medical production concept has been proposed to produce medical isotopes directly in the fuel solution, resulting in a potentially competitive alternative in comparison with the solid target irradiation method in heterogeneous reactors. Furthermore, the utilization of AHRs for medical isotopes production has been strengthened because of the successful operation of the ARGUS reactor since 1981 and its conversion to low-enriched uranium (LEU) fuel during 2012-2014. Those successes positively influenced in the decisions to construct a Proof-Of-Concept production site based on the ARGUS operational experience in Sarov (500 km from Moscow) and to restore the Argus-FTI at the Umarov Physical and Technical Institute in Dushanbe, Tajikistan. However, demonstrating the viability of the AHRs for medical isotopes requires solving several significant challenges related with the safe operation of these reactors. Consequently, not only for the design, licensing and safe operation of the AHRs, but also for the prediction of accident scenarios it is very important to be able to simulate and predict the behavior of the fuel solutions through a group of relevant physical parameters. Accordingly, this paper aims to show the advances made to improve the predictive capabilities during the multi-physics computational modeling of AHRs.
Highlights
The Aqueous Homogeneous Reactors (AHRs) mainly exist today as experimental and demonstrative facilities, with only two operational AHR at the beginning of 2020, the growing recognition of their unique characteristics makes them leading candidates for the present and future radioisotopes production, especially the 99Mo production [1,2]
Compared with a multipurpose research reactor, an AHR dedicated for 99Mo production has advantages such as (1) flexibility in operating power ranges according to the 99Mo demand, (2) high safety characteristics in terms of the large negative density coefficient of reactivity, (3) a reduction of 235U requirement compared with the current research reactors, (4) a significant reduction of waste generation, (5) far simpler waste management, and (6) no need of costs related to the fabrication, transportation, irradiation, disassembly and dissolution of targets [1,3,4,5]
2015 focused on the thermal-hydraulics study of the core of a 20 and 75kWth AHR based on the ARGUS reactor low-enriched uranium (LEU) configuration using ANSYS-CFX 14 code and an AHR model consisting of the vessel, the core channels, the coiled cooling pipe, the fuel solution, and the upper air zone
Summary
The AHRs mainly exist today as experimental and demonstrative facilities, with only two operational AHR at the beginning of 2020, the growing recognition of their unique characteristics makes them leading candidates for the present and future radioisotopes production, especially the 99Mo production [1,2]. The fuel in the AHRs is a soluble salt dissolved in water and acid which is contained in a shielded tank or vessel. Three types of aqueous fuel solutions have been used: uranium nitrate [UO2(NO3)2], uranium sulphate [UO2SO4], and uranium fluoride [UO2F2]. The AHR technology was highly researched in the early years of the nuclear age, with more than 30 solution reactors built worldwide and operated over many years, accumulating over 149 years of combined experience. The formation of gas bubbles and problems regarding the suitability of materials discouraged development of the technology for electricity generation [6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
