Assessment and improvement of resilience of NPP through advanced modelling and simulation

点击翻译按钮获取中文摘要

This collaborative research project with Candu Energy, Inc. includes five research topics which encompass a) long-term performance at the material level, b) inelastic behaviour of a reinforced concrete (RC) shell element, c) integration of state-of-art analysis tools to simulate a structural system, d) to assess seismic resilience of NPP system using the simulation tool and e) visualization of results. To understand the long-term creep and shrinkage behaviour of reinforced concrete structures, a specimen with surface-to-volume ratio similar to a typical NPP containment structure will be tested in the laboratory. The humidity and temperature boundary condition will be defined based on the internal environment of a typical containment structure. The experimental results will be used to develop a more accurate creep and shrinkage model through which the long-term dehumidification and shrinkage process of a containment building can be predicted. In the structural element level, a shell element with a reduced number of integration points will be developed based on modified compression field theory (MCFT). The numerical element will be able to predict the stiffness and failure process of an RC element including crack development and propagation under both static and dynamic loads. At the system level, the newly developed element will be integrated with other sophisticated numerical modelling tools that have been developed in University of Toronto. The integrated numerical model will allow modelling and simulation of a large nuclear power plant system under beyond-design level earthquakes and subsequent potential internal pressure increases. A series of analyses will be carried out to build a database of the structural responses, and a software tool will be developed to visualize the results. The response database and visualization tool will be used to support decision makers immediately after an earthquake event. Considering more than 50% of electric energy in Ontario relies on nuclear power, the accurate understanding on the resilience of NPPs will lead to a sustainable and resilient society.