Study of the seismic behaviour of GEN III plant
Abstract
External events are a significant source of hazards to nuclear power plant (NPP) operation, and for this reason it is of meaningful importance to investigate the existing operational nuclear reactors, even aged, in order to verify their structural capacity adequacy. This study aims at investigating numerically, by means of a deterministic approach, the dynamic behaviour of the structures, systems and components (SSCs) relevant for the safety of the plant when subjected to earthquake event. A quite refined finite element model (FEM) was thus set up and implemented considering suitable aged/not aged materials behaviour and constitutive laws for the SSCs material. Damping ratios of building materials of height >50 m (reinforced concrete and steel) have been adopted as well. Fifty acceleration time histories, representative of different soil conditions, were inputted to the transient analyses. The obtained results were used to appropriately check mainly the considered NPP containment strength reserve. Results seem to confirm the overall containment reliability even though buckling could affect some internal components. It was observed also that ageing induces a reduction of the plant structural capacity by about 20%.
Domains
Earth Sciences
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