Characteristic evaluation of high compression seismic isolator for International Thermonuclear Experimental Reactor (ITER). Verification test of sub-scaled rubber bearings. Contract research

The International Thermonuclear Experimental Reactor (ITER) is designed to withstand the seismic load of 2 m/s2 at the ground level as a standard seismic condition. In case of severe seismic load over 2 m/s2, an application of the seismic isolation to the tokamak building is studied so as to reduce the seismic load below 2 m/s2. The seismic isolation with high compressive pressure of 7.35MPa to 14.7MPa is considered as a candidate, because the tokamak weight is large to the building size and the number of seismic isolator (rubber bearing) is limited in the available space of the building. Although many studies were executed in the past in order to apply the seismic isolation to the nuclear plant, the test data can not be applied to the ITER due to low compressive pressure of about 2.45MPa to 4.90MPa. Based on the above, it is therefore necessary to evaluate the various kinds of dynamic and mechanical characteristics of the rubber bearings under the high compressive pressure and to obtain the database for the design of the seismic isolation system of the ITER. The report describes the summary of the test results of the sub-scaled rubber bearings executed under the high compression condition in 1997 to 1999. (author)