Optimal structural analysis with associated passive heat removal for AP1000 shield building

The shield building of AP1000 was designed to protect the steel containment vessel (CV) of nuclear power plants. When the reactor is shutdown, the tank mounted above the shield building sprays water, and the intake of ambient air cools down the temperature of CV through buoyancy driven circulation. The result of heat transfer analysis indicates that the location of air intake at lower altitude is more effective than that in the original design. However, pursuing superior heat transfer may cause a conflict with the structural strength, particularly under the threat of an earthquake. Therefore, this study identified the optimal design for stress analysis to improve passive cooling. The results of structural analyses indicated that the maximal stresses developed under various water levels were in the acceptable range of yield stress limits for concrete. The water level does not pose considerable danger to the structure. In addition, the simulation result also indicated that an optimal parametric design for air intake must be implemented around the middle of the shield building, with 16 circular or oval shaped air intake.