Thermal-hydraulic characterization of a 50-kW medicinal-aimed aqueous homogeneous reactor (MAHR)

Abstract

This paper analyses the thermal–hydraulic performance of a proposed 50-kW aqueous homogeneous reactor (AHR) aimed at producing Mo-99. The reactor thermal–hydraulic characteristics are analyzed using ANSYS-FLUENT software and Relap code, and the results are validated through experiments conducted by a prototypic cylindrical sector of the reactor vessel. Boundary conditions in the CFD simulation are set up based on Relap modelling, while CFD outputs are validated by experimental results achieved using the laboratory model. Then, various parameters, including coolant mass flow rate, first cycle pipe diameter, coolant outlet temperature, average fuel solution temperature, and the elevation difference between the reactor and heat exchanger, are optimized using the least-squares optimization method. Results demonstrate that the heat removal system provides sufficient cooling capacity to ensure stable operation of the proposed AHR core by preventing fuel solution overheating and, consequently, boiling (void formation) in the active fuel solution.