AbstractIn a strong earthquake area, it is difficult to ensure the integrity of the tokamak machine because of its own structure. In order to solve this problem, a partial seismic isolation method is studied in the engineering design activities (EDA) of the International Thermonuclear Experimental Reactor (ITER). However, the relative motion between the unisolated and isolated parts of the building will be relatively large, from 5 to 15 cm in any horizontal direction and from 1 to 2 cm vertically, depending on the characteristics of the isolators. In order to realize this partial seismic isolation method, a feasibility of layout of the services (pipes, busbars, etc.) across the seismic gap must be shown ensuring their integrity during earthquake. In this paper we deal with some layout examples of the services with special support devices and expansion joints by using the conventional analytical simulation method. As a result of the analysis, it is found these services can cross the seismic gap during the strong earthquake ensuring their integrity. However, they require more space than that of the conventional seismic design.