Fragility analysis of a prestressed concrete containment vessel subjected to internal pressure via the probability density evolution method

The prestressed concrete containment vessel (PCCV) is the final barrier to prevent radioactive material leakage from a nuclear power plant to the outside. Therefore, the fragility evaluation is very important for the design and analysis of the PCCV. In this paper, the fragility analysis of the PCCV (tested at Sandia National Laboratories (SNL)) subjected to internal pressure is conducted using the probability density evolution method (PDEM). First, a high-fidelity finite element analysis procedure is introduced to perform the deterministic analysis of the PCCV. In the following stochastic analysis and fragility evaluation, the material properties are selected as the uncertain resources. By applying the PDEM, the probability surface and probability density function (PDF) of the stochastic responses are obtained. Furthermore, the limit state of the PCCV is evaluated by the global average strain, which is defined as the ratio of radial displacement to the radius of the PCCV, and the PCCV reaches its functional and structural failure states when the global average strain reaches 0.4% and 1.5%, respectively. To consider more than one failure mode in the fragility evaluation, an equivalent extreme-value event combined with the PDEM is adopted to obtain the failure probability and the fragility curve of the PCCV to evaluate its fragility behavior. The results show that the fragility of the PCCV is still zero until the internal pressure increases to 2.890 times and 3.155 times the design pressure and then increases rapidly and reaches 1 at 3.560 times and 3.955 times the design pressure of the functional and structural failure criteria, respectively.