Implementation of a Multi-cell Approach in the Multi-Physics Calculations of an Aqueous Homogeneous Reactor

Abstract

Nowadays, the Aqueous Homogeneous Reactor (AHR) technology is under study for its use in the production of medical isotopes. This technology has proven to be potentially advantageous for this purpose due to its low cost, small critical mass, inherent passive safety, and simplified fuel handling, processing, and purification characteristics. Among the studies being carried out is computational modeling and simulation, which represents a key technology in the pursuit for improvements in efficiency, safety, and reliability of these systems. This paper aims to expand upon a previous AHR computational model through the implementation of a multi-cell approach for the improvement of the calculations using a methodology for the multi-physics and multi-scale coupling of the neutronic and thermal-hydraulic codes. It was found that these additions to the original model cause a small change to the overall reactor behavior. Thermal-hydraulic parameters such as, average fuel solution temperature and velocity, gas volume fraction and average radiolytic gas bubbles velocity undergo a variation of 0.161 °C, 0.0009 m/s, 0.015% and 0.0003 m/s. In contrast, significant local differences were obtained mainly for the fuel solution temperature and radiolytic gas bubbles volume fraction. It was verified that a simplified AHR computational model consisting of a 20° section of the fuel solution is able to adequately reproduce the results of the full AHR computational model.