Performance-Based Seismic Design of the Main Plant Building for Thorium-Based Molten Salt Reactor （TMSR-LF1） Considering Risk Classification and Performance Objectives

China has not yet established dedicated seismic design standards for research reactors. While conventional industrial and civil building codes fail to account for the radiological characteristics of nuclear facilities， adopting seismic design standards for nuclear power plants would be overly conservative. This paper systematically examines the latest U.S. standard Seismic Design Criteria for Structures， Systems， and Components in Nuclear Facilities（ASCE 43-19）， and integrates it with China’s Seismic Design Standard for Nuclear Power Plants（GB 500267-2019） and Code for Seismic Design of Buildings （GB/T 50011-2010）to propose a risk-informed， performance-based seismic design methodology for nuclear facilities. For the seismic design of TMSR-LF1 building in Wuwei， Gansu Province， considering factors including safety functions， radiological risks， owner requirements， structural characteristics， and cost-effectiveness， this study establishes the design basis ground motion and defines performance objectives for both the overall structure and different components under the specified levels of frequent earthquakes （service-level）， design basis earthquakes， and rare（maximum considered） earthquakes to meet these performance requirements. The risk-categorized， performance-based design method proposed in this paper for the TMSR-LF1 project achieves both precision and cost-effectiveness in research reactor seismic design. This methodology can be extended to other nuclear research and test facilities.