Soil–structure interaction analysis of nuclear power plant considering three-dimensional surface topographic irregularities based on automatic octree mesh

Abstract

Many nuclear plants are located near the shoreline and distant from populated areas to dissipate the enormous residual heat and regulate radioactive risk. However, the topography of the shoreline, including hills and valleys near the site where a nuclear power plant (NPP) is built, may affect the dynamic characteristics of NPP facilities and structures, as confirmed by numerical simulations and field observations. Partly due to the lack of efficient mesh generation and calculation methods for sites with three-dimensional surface topographic irregularities, numerical soil–structure interaction (SSI) analyses of NPPs considering topographic irregularities are rare. Moreover, if a simplified SSI analysis is performed, an inaccurate simulation of the real situation is inevitable. In this study, an efficient and universal SSI method that can conveniently consider topographic irregularities based on the geographic information system, octree mesh, scaled boundary finite element method, and direct method was established for efficient dynamic analysis in the time domain. The AP1000 nuclear island structure and a certain site with hills and valleys were selected as examples to confirm the practicability of this model. The dynamic response of the site showed that the acceleration response tended to be amplified in the hills and minified in the valleys. The dynamic response of the NPP structure confirms that ignoring topographic irregularities may not lead to a conservative assessment of the dynamic response of the NPP in the SSI analysis.