Analysis of flow distribution and bypass flow for DHR-400 low temperature heating reactor

Flow distribution at the core inlet and the fraction of bypass flow are important aspects of thermal hydraulic design for reactor. Three-dimensional fluid dynamics analysis was used to numerically simulate the overall flow phenomenon in the pool type low temperature heating reactor. Model of porous media was used to modify fuel assemblies. Thermal hydraulic parameters such as flow distribution of inlet and bypass flows were obtained. The results show that the deviation between the maximum flow rate and the average flow rate at the core inlet is 4.36 %, and the deviation between the minimum flow rate and the average flow rate is −3.08 %. The fraction of bypass flow of reflectors is 2.3 %, and the fraction of bypass flow between baffles and core shroud is 0.34 %. The total pressure drop from inlet to outlet is 56.8 kPa. It can be concluded that the distribution of inlet is relatively uniform, and the fraction of bypass flows is within the allowable range. The calculation results can provide a basis for subsequent engineering design.