Study on the long-term passive cooling extension of AP1000 reactor

The AP1000 with high safety is a generation III pressurized water reactor (PWR), its significant feature is passive safety system. However, its passive cooling can only maintain for 72 h and requires additional support from inside or outside the plant. To solve this problem, this study utilized the WGOTHIC software to calculate and analyze the water inventory in the passive containment cooling water tank under different conditions. The results show that when the cooling water inventory is 6553.78 m(3), the AP1000 nuclear power plants can achieve long-term, completely passive cooling without any inside or outside the plant. The same outcomes occur when 65-mm-thick containment wall increases the design pressure rating to 0.6 M-Pa at the cooling water inventory of 5673 m(3). Also, the AP1000 shield building was accordingly improved. An ANSYS analysis of the structural stability of the shield building with a 6000 m(3) cooling water inventory confirmed that the new design can meet the requirements of the seismic design and the safe residual heat removal requirements of a large-scale PWR.