Performance Assessment of Passive Containment Cooling System Using MAAP5 Code in Pressurized Light Water Reactor

It provides long-term cooling capability without external power supply and human intervention. The heat resulting from accidents is transferred to the passive containment cooling tank (PCCT) located outside of containment via heat exchanger placed inside of containment. In this paper, we carried out a thermal-hydraulic performance assessment of PCCS applied to Zion-like 4-loop nuclear power plant, a representative pressurized light water reactor (PWR) by using MAAP5.05 beta version code. A new PCCS model has been being developed for MAAP5 code. The new model consists of containment gas side heat transfer model including condensation effect and natural circulation of two-phase flow in the tube-side of a heat exchanger. In the present study, the PCCS model is tested for Zion-like 4 loop PWR. The results show that the PCCS can remove the decay heat in the containment and prevent the containment failure. However, the decay heat in the containment building is not reduced significantly in the late phase of accident in case of without long-term management of the PCCT water tank. Therefore the detailed assessment of the long term heat removal capability of the PCCS should be performed is expected.