Evaluation of the vibration response of third generation nuclear power plants with isolation technology under large commercial aircraft impact

Abstract

With the development of nuclear power technology, third-generation nuclear power plants (NPPs) are being built in many places. Examples include the American passive AP1000 NPP, the French EPR NPP, and China's Hualong One NPP. These will become the main reactor type for future NPP construction. Base isolation is employed as the aseismic technology in NPPs, and its design standard has been standardized according to ASCE 4–16 and other related codes. Since the 9/11 terrorist incident, large commercial aircraft impact (AI), as a beyond design-basis event, has attracted increasing attention in nuclear research. In the case of a third-generation NPP with isolation technology, it is necessary to evaluate its safety and integrity against AI. In this study, the dynamic response of a base-isolated third-generation NPP subjected to impact by a large commercial aircraft, the Airbus A340-300, is investigated. The most typical design for a third-generation NPP is to build many buildings on the same base-mat. The presence of a flexible isolation layer renders the dynamic behavior of a base-isolated NPP different from that of a non-isolated NPP under AI loads. Five key factors, including the horizontal stiffness of isolation bearings, horizontal damping of isolation bearings, total weight and weight distribution of the NPP, and AI force and direction affect the vibration characteristics of NPPs. The horizontal stiffness of isolation bearings affects the constraint effect of the foundation on the superstructure, while the damping of isolation bearings affects the dissipation of impact energy. Meanwhile, the total weight and weight distribution of the NPP affect the vibration response of different regions, and the impact force affects the vibration intensity of the NPP.