Research on Multi-Scale Coupling Computational Methods and Code Development for Pebble Bed High-Temperature Gas-Cooled Reactors

This study aims to design a new multi-scale coupling method and develop a corresponding code for the core of pebble-bed high-temperature gas-cooled reactor (HTGR). This research independently designed a multiscale coupling calculation framework that integrates macro-mesoscopic-microscopic models, specifically for pebble-bed high-temperature gas-cooled reactors, based on the C/C++ language. Macroscopically, a two-dimensional axisymmetric modeling method is adopted, and thermal conduction, fluid dynamics and neutron transport processes are coupled to establish the corresponding physical models. Mesoscopically and microscopically, the initial results from macroscopic calculations are used to calculate the temperature distribution at the fuel pebble scale and the TRISO particle scale using the heat source decomposition method, enhancing computational efficiency. The results of the study demonstrate that the independently developed multi-scale coupling code can effectively simulate various operating conditions of HTR-PM and HTR-10 reactor types, providing significant theoretical support and technical assurance for their design and safety assessment.