Analysis of the vibration characteristics of a reactor building based on artificial waves using ACROSS

Nishida, Akemi  ; Choi, B. ; Kang, Z.  ; Shiomi, Tadahiko; Iigaki, Kazuhiko ; Yamakawa, Koki*

Our research and development are aimed at improving the accuracy of the three-dimensional seismic analysis of nuclear buildings to better understand their three-dimensional seismic behavior in response to enhanced regulatory requirements on impact assessment against external events such as earthquakes. In 2019, we constructed a large-scale observation system for the High Temperature Engineering Test Reactor (HTTR) building of the Japan Atomic Energy Agency (JAEA) in collaboration with the Nuclear Regulation Authority (NRA) and JAEA. Since then, we also conducted several excitation tests by the ACROSS system and obtained observation record at many accelerometers using the observation system. These records are important since the excitation source is clearly defined unlike earthquake's uncertain transmission pathway. In this paper, we focus mainly on the vibration characteristics of the entire building and report on these observation records and the characteristics, such as the dominant frequencies and corresponding three-dimensional deformation modes.