Abstract: Accurate and reliable reactor thermal hydraulic analysis has important significance for the design and safe operation of the pebble bed modular high temperature gas-cooled reactor. Based on the helium coolant flow and heat transfer process at the core of high temperature gas-cooled reactor, we establish a three-dimensional coupled model by using CFD (computational fluid dynamics) software to simulate the flow and heat transfer of helium coolant at the core. Then the model is verified by comparison of the calculation results with the published results using THERMIX software. The results show that the steady-state results using the three-dimensional model are in agreement with THERMIX calculation data under the rated working conditions, and the relative error is less than 1%. The three-dimensional model simulates the coolant temperature distribution at the core. The research results lay the foundation for the subsequent analysis of complex thermal hydraulic phenomena such as core bypass of high temperature gas-cooled reactor.

Key words: high temperature gas-cooled reactor, pebble bed, thermal hydraulics, porous media, CFD(computational fluid dynamics)