Parameter study on dynamic behavior of ITER tokamak scaled model

Nakahira, Masataka; Takeda, Nobukazu; Urata, Kazuhiro*

This report summarizes the study on dynamic behavior of ITER tokamak scaled model according to the parametric analysis of base plate thickness, in order to find a solution to give the sufficient rigidity without affecting the dynamic behavior. For this, modal analyses were performed changing the base plate thickness from the present design of 55mm to 100, 150 and 190 mm. It was found that the thickness of 150mm gives well fitting of 1st natural frequency about 90% of ideal rigid case. Thus, the modification study was performed to find out the adequate plate thickness. Considering the material availability, transportation and weldability, it was found that the 300mm thickness would be a limitation. The analysis result of 300mm thickness case showed 97% fitting of 1st natural frequency to the ideal rigid case. It was however found that the bolt length was too long and it gave additional twisting mode. As a result, it was concluded that the base plate thickness of 150mm or 190mm gives sufficient rigidity for the dynamic behavior of the scaled model.