Capability of RELAP5 code to simulate the thermal-hydraulic characteristics of open natural circulation

In the present study, one of the extensively used best estimate code RELAP5/MOD3.3 was used to simulate the thermal-hydraulic behaviors of an open natural circulation loop (PCCS-TF). The simulation results were validated against the corresponding experimental data performed on the PCCS-TF. The comparison results showed that RELAP5 code can successfully simulate most of the thermal-hydraulic transients, the flow mode distribution and the static characteristics of the open natural circulation system, in view of the simulation results reproduce in good agreements with the experimental data. Moreover, the influences of the structure parameters on the thermal- hydraulic behaviors were also researched, with the help of RELAP5 code to provide the technical supports for the design of the open natural circulation.