Three-Dimensional Simulation of Natural Circulation in a Passive Condensate Cooling Tank of a Passive Feedwater Auxiliary System using the CUPID Code

摘要

Thermal hydraulic phenomena in the Passive Condensate Cooling Tank (PCCT) of the Passive Auxiliary Feedwater System (PAFS) in the Advanced Power Reactor Plus (APR+) is analyzed using the CUPID code, which has been developed to analyze multi-dimensional thermal hydraulics issues. The capability of CUPID code in simulating the natural circulation in the secondary loop of PCCTs including subcoolled boiling, flashing, the transition of the natural circulation mode, evaporation, transient temperature, and the decreasing rate of the collapsed water level in two dimensions had been validated. In this work, the full scale PCCT of PAFS is simulated in three dimensions using the CUPID code and considered headers of the heat exchanger tubes. The single- and two-phase natural circulation phenomena of the full scale PCCT of PAFS are successfully simulated including the boil-off transient. This paper presents the description of the full scale PAFS facility, the models and correlations related with PAFS simulations and the three-dimensional simulation results using the CUPID code.