Thermal Hydraulic Behavior of SCWR Sliding Pressure Startup

The modification to ATHLET-SC code is introduced in this paper,which realizes the simulation of trans-critical transients using two-phase model.With the modified code,the thermal-hydraulic dynamic behavior of the mixed SCWR core during the startup process is simulated.The startup process is similar to the design of SCLWR-H sliding pressure startup.The results show that maximum temperature of clad-ding-surface does not exceed 650℃ in the whole startup process,and the sudden change of water properties in the trans-critical transients will not cause harmful influence to the heat transfer of the fuel cladding.