Nonlinear Seismic Response Characteristics of CAP1400 Nuclear Island Structure on Soft Rock Sites

Furong Li,Guoxing Chen

doi:10.1155/2020/8867026

Abstract

CAP1400 nuclear island structure is an advanced and novel nuclear power plant structure. In order to explore the seismic response characteristics of CAP1400 nuclear island structure on soft rock sites, a three-dimensional refined nonlinear seismic response analysis model was established for a soft rock foundation-nuclear island structure system using ABAQUS software. The influences of the input ground motion intensity and the frequency spectrum characteristics on the acceleration, relative displacement, and floor response spectrum, as well as the critical shear wave velocity of nonbedrock sites for CAP1400 nuclear island structure, were proposed. The results suggested that the increasing amplitude of the peak acceleration and relative displacement of nuclear island structure decreased as the soft rock site entered a nonlinear state, and the high-frequency components of the input ground motion became more abundant. Specifically, the earthquake response was the largest at the cooling water tank on the top of the shield building, which was the focus of the seismic research on nuclear island structure. Due to the influence of the ground motion frequency spectrum characteristics and the nonbedrock site effect, the peak acceleration, peak relative displacement, and acceleration response spectrum of the nuclear island structure showed different changing trends for the near-field and far-field ground motions. Based on the influence of the site shear wave velocity on the seismic response of nuclear island structure, it was recommended that the critical shear wave velocity of nonbedrock sites for CAP1400 nuclear island structure should be 1250 m/s, and the nuclear island structure-foundation dynamic interaction could be ignored at this time. The research conclusions could provide some technical support and theoretical basis for the construction and seismic performance research of CAP1400 and other nuclear power plants.

Highlights

According to the statistics of the International Atomic Energy Agency, nuclear power generation accounts for about 10% of global power generation and nearly 1/3 of lowcarbon power generation
It can be seen from the figure that the acceleration response of each observation point showed a magnification effect in a different degree because of the spatial structure characteristics of the nuclear island and the spectrum characteristics of the input ground motion
It can be seen from the figure that, with the increase of the height, the Peak Floor Acceleration (PFA) of the shield building (SB), steel containment vessel (SCV), auxiliary building (AB), and containment internal structure (CIS) generally increased to varying degrees

Summary

Introduction

According to the statistics of the International Atomic Energy Agency, nuclear power generation accounts for about 10% of global power generation and nearly 1/3 of lowcarbon power generation. Tuñon-Sanjur et al analyzed the seismic response characteristics of AP1000 nuclear island structure on general hard bedrock sites using ANASYS finite element software, and they designed five types of nonbedrock sites that needed to consider SSI [1]. Wang and Yang established an AP1000 nuclear island finite element model and analyzed the seismic response of a nuclear island structure under different foundation conditions by considering the foundation embedment and SSI [11]. Li et al established a finite element model by considering the foundation-nuclear island structure interaction, and they analyzed the seismic response of the contact area between the shield building and the foundation soil for different types of sites and different ground motion inputs [12]. According to the influence of the shear wave velocity on the seismic response characteristics of the nuclear island structure, the critical shear wave velocity of nonbedrock sites suitable for CAP1400 nuclear island structure was proposed. is research provides a theoretical basis for nuclear power plant construction and seismic performance research

Finite Element Model of CAP1400 Nuclear Island Structure

Floor Acceleration

Study of the Critical Shear Wave Velocity of Nonbedrock Sites