Buckling analysis for the center post of low aspect ratio tokamak

The center post is one of the critical components for the low aspect ratio tokamak reactor device, which endure not only a tremendous ohmic heating due to its carrying a rather high current but also a large neutron heating and irradiation owing to the plasma operation. The DS copper alloy, Glidcop® AL-25 was chose as the conductor material for its adequate mechanical properties and physics properties. The center post has a cylinder structure with lots of cooling channels. The length of center post for the next generation nuclear fusion spherical tokamak reactor device will be more than 10 m or 20 m. The structure stability is very crucial for them. When the applied load is very large and over the structure critical buckling load, the device will lose its stability and collapse. In order to calculate the critical buckling load, a 1/6-segment finite element model was used and the force acting on the center post was simulated. The analysis results have shown that vertical compressive stresses mainly affect factor for the stability of center post. The paper has given the linear buckling analysis results with finite element method based on the small deformation theory. The relation curves and functions for the buckling factor depended on the different length of center post, radius of center post, diameter of the cooling channel and the maximum allowable current density have also been shown.