Ultimate pressure bearing capacity analysis for the prestressed concrete containment

PWR nuclear power technology has been developed in China according to the experience feedback of the Fukushima accident and the global latest safety requirements, in which the double-containment design with hemisphere dome having larger free space is adopted. Ultimate pressure bearing capacity of the Prestressed Concrete Containment Vessel (PCCV) is analyzed in this study to provide technical support for development of Severe Accident Management Guidelines (SAMG) in nuclear power plants. Firstly, the finite element model of the PCCV is built, including the concrete, the rebars, the prestressed tendons, the steel liner, and penetrations. Combining of free-sweep mesh is adopted according to the characteristics of the containment structure. Proper mesh size is determined through mesh sensitivity analysis. Prestressing loss is calculated for four types of prestressed tendons, and decreasing temperature method is adopted in prestressing simulation. Temperature field of the containment is calculated, and stratified temperature method is adopted in temperature simulation. Ultimate pressure bearing analysis results show that, with the increase of internal pressure, the containment gradually expands outward, and the maximum stress and maximum radial deformation of the containment appear near the equipment hatch. When the internal pressure load reaches 1.26 MPa (g), the equivalent plastic strain of the steel liner in the right area of the equipment hatch is 0.15%. At this time, the concrete cracks on a large area, and the prestressed tendons do not yield.