In view of the complex thermal and hydraulic phenomena in various systems and equipment of nuclear reactors, the refined experiments and simulation studies of reactor thermal hydraulics are carried out to break through the key technical bottlenecks of the measurement of thermal parameters in complex channels and the simulation of complex objects, and realize the full-field measurement and analysis of high spatiotemporal resolution such as flow field, temperature field and concentration field in various types of fuel assemblies and pressure vessels, as well as the three-dimensional full-scale refined numerical modeling and simulation of key systems and equipment, so as to support the design, verification and optimization of a new generation of nuclear power systems and equipment.