On component isolation of conceptual advanced reactors

• Published in: Nuclear engineering and technology Vol. 54; no. 8; pp. 2974 - 2988
• Main Authors: Shrestha, Samyog, Kurt, Efe G., Prakash, Arun, Irfanoglu, Ayhan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-08-2022; Elsevier; 한국원자력학회
• Subjects: Component isolation; Friction pendulum; MASTODON; Nuclear; Reactor vessel; Soil-structure interaction; 원자력공학; Soil-structure interaction; Friction pendulum; Reactor vessel; Nuclear; Component isolation; MASTODON
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2022.02.012

Implementation of component isolation in nuclear industry is challenging due to gaps in research and the lack of specific guidelines. In this study, parameters affecting component-level isolation of advanced reactor vessels are identified based on a representative numerical model with explicit consideration of nonlinear soil-structure interaction (SSI). The objective of this study is to evaluate the effectiveness of, and to identify potential limitations of using conventional friction pendulum bearings to seismically isolate vessels. It is found that slender vessels or components are particularly vulnerable to rotational accelerations at the isolation interface, which are caused by rotation of the sub-structure and by excitation of higher modes in the horizontal direction of the seismically isolated system. Component isolation is found to be more effective for relatively stiffer vessels and at sites with stiff soil. Considering that conventional isolators are deficient in resisting axial tension, it is observed that the optimum location for supporting a component to achieve seismic isolation, is at a cross-sectional plane passing through the center of mass of the vessel. These findings are corroborated by numerous simulations of the response of seismically isolated reactor vessels at different nuclear power plant sites subject to a variety of ground motions.