Structure Analysis And Optimization Of CFETR Vacuum Vessel Mock-Up

Nuclear fusion energy is a clean energy with strategic significance.The China Fusion Engineering Text Reactor(CFETR)is a fully superconducting tokamak that builds a technical bridge between the International Thermonuclear Experimental Reactor(ITER)and the Fusion Demonstration Power Station(DEMO).Vacuum vessel(VV),as a key component to maintain the stable operation of tokamak,plays an important role in the safe operation of the device.The vacuum vessel gravity support(VVGS)is a key component that carries the gravity and various mechanical loads of the vacuum vessel and its internal components.The construction of the CFETR VV mock-up is to study the key issues of VV processing and manufacturing,mechanical analysis and other issues.The structural design of CFETR VVGS mocuk-up and the simulation analysis of its working conditions were carried out,and Isight software was used to optimize the structure of gravity-supported elastic plates.The main work contents are as follows:1.Through research on the development of nuclear fusion and tokamak devices,the background and development of controlled nuclear fusion are briefly introduced.Subsequently,the functions of the VV in the fusion reaction and the development status of the major tokamak devices in the world were reviewed,leading to the research content and significance of this dissertation.2.After comparing the advantages and disadvantages of different design schemes,the structural design scheme of CFETR VVGS mock-up was determined.Using CATIA 3D software,the detailed structure model and simplified model of the VV and its gravity support were established,and 316L(N)was selected as the material of the VV and its material properties were analyzed.Through the finite element commercial software ANSYS Workbench,the finite element analysis of the VV is carried out,including single working condition analysis and combined working condition analysis.The displacement and equivalent stress distribution of the VV and its gravity support under each working condition can be obtained.The displacement and stress conditions of each working condition in the whole vacuum chamber and its gravity support position are sorted out and checked,which lays the foundation for the input of subsequent optimization parameters.3.The simulation analysis of the VV is carried out,including single working condition analysis and combined working condition analysis,to obtain the displacement and stress distribution of the VV and its gravity support under each working condition.After the stress evaluation,the design of the VV and its gravity support meets the design standards.The combined working condition with the largest load is BK+SL-2,which is used as the working condition of the subsequent gravity support structure optimization process.4.In the multi-objective optimization design of the VVGS's elastic plate,the maximum effect of the sensitivity analysis quality is the height and clearance of the elastic plate,and the quantity is most related to the thickness of the elastic plate.Among the 1000 sample points,the optimal structure parameters of the CFETR VVGS mock-up were obtained.Compared with the initial design structure,the optimized design does not change the overall structural performance of the VV,but its quality is reduced by 37%,indicating that this optimization has a good effect.In the GS's elastic plate after optimization,the height is 1180mm,the thickness is 40mm,the gap between the plates is 70mm,and the number is 13 pieces which are evenly distributed between the upper and lower baffles.The structure of the VVGS studied and designed in this dissertation meets the requirements of use and has a simple structure.The design structure and research method of this dissertation have laid a data foundation for the subsequent research and development of CFETR,and are also applicable to the similar support structure of Tokamak.