Evaluation of Dome–Cylinder Interface of Prestressed Concrete Containment Subjected to Nuclear Accidental Thermal and Pressure Loads

A prestressed concrete containment vessel (PCCV) serves as the final physical barrier for nuclear reactors, with its structural integrity being critical to prevent radioactive release during accident scenarios. Addressing structural complexity at the dome–cylinder interface of prestressed concrete containments, arising from its geometric discontinuities and complex stress concentrations, this study systematically investigates the structural behavior and force distribution under coupled thermal and internal pressure loads due to nuclear accident. A parametrical nonlinear finite element (NLFE) PCCV model based on concrete damaged plasticity (CDP) theory is developed and first validated using the results from two different experimental tests. The validated NLFE model is then used to conduct a series of parametrical studies that are based on the practical example of nuclear PCCVs in China. The effects of various design parameters including the dome–cylinder thickness ratio, reinforcement ratio, accidental temperature and accidental pressure loads are studied in detail. The results show that current practice in nuclear concrete containment design using linear FE with a reduced concrete modulus may significantly underestimate both the moments and shear forces at the dome–cylinder interface, by factors of up to 1.55 times and 3.91 times, respectively. In conclusion, this work quantifies the shear amplification effect driven by the stiffness redistribution mechanism and proposes specific amplification factors to ensure the structural integrity of containment vessels under severe accident conditions.