Dynamic Analysis of ITER Tokamak Using Simplified Model for Support Structure

摘要

The simplified analytical model of a support structure composed of complicated structures such as multiple flexible plates was proposed for dynamic analysis of the ITER major components of the VV and TF coil. The support structure composed of flexible plates and connection bolts was modeled as a spring model composed of only two spring elements simulating the in-plane and out-of-plane stiffness of the support structure with flexible plates including the effect of connection bolts. The stiffness of both these spring models for the VV and TF coil agree well with that of shell models simulating actual structures such as flexible plates and connection bolts. It is therefore found that the spring model with only these two parameters, in-plane and out-of-plane stiffness, simplifies the complicated support structure with flexible plates for the dynamic analysis of the VV and TF coil. Using the proposed spring model, the dynamic analysis of the VV and TF coil for the ITER were performed to estimate the integrity under the design earthquake at Rokkasho, a candidate for an ITER site. As a result, it is found that the maximum relative displacement of 8.6 mm between the VV and TF coil is much less than the current design gap of 100 mm, so that the integrity of the major components (VV and TF coil) of the ITER tokamak device is ensured for the expected earthquake event.