Research On Key Technologies Of Welding Tools For Nuclear Fusion 1/8 Vacuum Vessel Sector

The Tokamak device is main reactor of nuclear fusion,and as the installation basis of magnet,divertor and other components,vacuum vessel is an important part of Tokamak device,too.The vacuum vessel is a "D" shell structure with a height of about 11 m and a width of about 6m,which requires high welding accuracy.In this paper,a special welding tool for 1/8 sector of vacuum vessel and the method of correcting the possible welding deformation after welding are put forward,which is verified by the experiment.The main contents include:Firstly,according to the 1/16 sector model of vacuum vessel,the special welding tooling for tailor-welded 1/8 sector process is designed.The device includes clamping mechanism,supporting mechanism,regulating mechanism and driving mechanism.The specific components include double-deck tower column,encircling arm,supports,hydraulic cylinder,etc.In the design of supports,the optimization program is expanded,and the structure and shape of the vacuum vessel are optimized accordingly.Secondly,the possible welding deformation after vacuum vessel welding is analyzed theoretically,and the relationship between wall pressure bending rate and springback curvature of vacuum vessel is calculated based on mechanical correction method,and the reverse deflection required for mechanical correction is calculated.Finally,the finite element analysis software is used to simulate the stress and strain of the truncated part of the vacuum vessel wall,and the yield deflection under different loads is obtained according to the results.Finally,through the bending test of the model of the vacuum vessel,the load of different sizes is applied to the truncated part by hydraulic press,and the deflection of the truncated part is measured and compared with the theoretical calculation results.The comparison results show that the experimental data basically accord with the theoretical analysis.The significance of this paper lies in the design of a set of welding tooling for 1/8 vacuum vessel sector,which includes supporting device,adjusting device and clamping device,effectively guaranteeing the accuracy of the docking of 1/16 sectors.At the same time,the straightening theory is put forward to solve the problem of the deformation of the double-layer wall of the vacuum vessel,which provides theoretical guidance for the welding and rectification of the vacuum vessel sector in the future.