Key Technical Researching For The Coil Winding Of The CFETR CS Model Coil

Chinese Fusion Engineering Testing Reactor(CFETR)will be built in China,which is to conduct the scientific research on stable,efficient and safe fusion reactor.The central solenoid(CS)coil is one of the critical components of the CFETR magnet system.The research on the key technology of CFETR CS model coil is being carried out to develop the key technology of large-scale CS superconducting coil.And this project is aiming to complete the manufacturing and performance evaluation of the model coil.High precision winding is one of the key technologies for manufacturing model coil.The main content of this paper is as follows.The winding design and tolerance analysis of the model coil are completed.The design of the circular turn transition with double positive circular segments is innovatively proposed,which greatly reduces the number of forming radius of turns.The preliminary design of S-type pancake joggle and terminal transition bend is completed.Based on the tolerance analysis theory,the tolerance analysis of winding geometry is completed,and the winding tolerance requirements are put forward.The forming technology of S-type pancake joggle and the short sample test are completed.According to the overall tolerance requirements of winding and the process of joggle deposited into mold,the geometric tolerance requirements of joggle are developed.In order to optimize the joggle length and the radius of the front arc surface of the clamping die,the combined process of push-bending,stretch-bending and re-shaping is innovatively developed.The design and analysis of the stretch-bending tooling are completed.The short sample forming test of joggle is carried out.Simulation study and short sample test verified the feasibility of joggle forming technology.The simulation study of circular turn forming and short sample test are completed.Based on the static implicit algorithm,the finite element simulation study of push-bending of circular turn was carried out.The deformation,stress and strain in the whole process of push-bending are analyzed,and the length of key plastic forming area is determined.The load input of roller reaction force for winding machine design is obtained.The short sample test of push-bending for circular turn is carried out.Simulation study and short sample test verified the feasibility of the process of continuous push-bending with multi-rollers method.The winding production line is designed preliminarily,and the design analysis and test verification of the key winding equipment are completed.The structural design and mechanical analysis of winding machine,winding die and rotating platform are carried out.The reliability and stability of the key winding equipment are verified by single machine test.The winding production line is built and in commissioning by 10×4 dummy coil winding.The continuous winding of the Nb3Sn inner coil is completed.The winding production line is successfully built to meet the requirements of CICC with large section cross,small bending radius and multi-pancakes characteristics.The winding of 10×4 dummy coil is carried out,and the commissioning of the winding production line is completed.The feasibility of the continuous winding technology and the reliability and stability of the winding equipment are verified.The coil winding of the Nb3Sn inner coil is completed.The process control parameters and the dimensions and form tolerances of the winding basically meet the design requirements.