Seismic analysis of ITER tokamak including interaction with soil and building

A coupled spectrum seismic analysis of the ITER ‘tokamak-building-basemat-soil’ system has been performed. Soil–structure interaction (SSI) is modelled as a set of springs and dampers. A new method is proposed to replace the detailed finite-element model of the building by an equivalent set of parallel oscillators having the same natural frequencies, modal effective masses and height as the building and creating the same shearing force and overturning moment. The response of the ITER tokamak is found versus different soil parameters. For some particular soil conditions, the natural frequency of the building is very close to that of the tokamak and critical resonance effects may take place.