Preliminary Analysis of the Thermal-Hydraulic Performance of a Passive Containment Cooling System using the MARS-KS1.3 Code

Abstract - A passive containment cooling system has been design ed to remove the heat inside a containment during accidents without external power supply. In this work, t he PCCS was introduced in the APR1400 plant to replace the containment spray system and, then, the thermal-hydraulic performance of the PCCS was analyzed using the system thermal-hydraulic computer code, MARS. A double-ended cold-leg break accident, which is known to induce the maximum pressure in the containment, is simulated, where the thermal hydraulics of the PCCS, the reactor coolant system, and the containment are simultaneously simulated. The results of the calculations showed that the PCCS can replace the existing spray system and that the containment building and its internal structure al so play a very important role for the heat removal during the accident. Some sensitivity calculations were carried out to evaluate the model uncertainty and the effects of design parameters. The limitations of the PC CS are also discussed.