Reliability analysis of 500 MWe PHWR inner containment using high-dimensional model representation

In this paper, uncertainty analysis of Indian 500 MWe Pressurized Heavy Water Reactor (PHWR) subjected to an accidental pressure is carried out using a computational tool based on High Dimensional Model Representation (HDMR) that facilitates lower dimensional approximation of the original high dimensional implicit limit state/performance function. The method involves response surface generation of HDMR component functions, and Monte Carlo simulation. HDMR is a general set of quantitative model assessment and analysis tools for capturing the high-dimensional relationships between sets of input and output model variables. It is very efficient formulation of the system response, if higher-order variable correlations are weak, allowing the physical model to be captured by first few lower-order terms. Once the approximate form of the original implicit limit state/performance function is defined, the failure probability can be obtained by statistical simulation. Reliability estimates of PHWR inner containment subjected to an internal pressure exceeding the design pressure, considering three stages of progressive failure prior to collapse are presented.