Key manufacturing technologies of the CFETR 1/8 vacuum vessel sector mockup

Abstract

• Key technology types involved in CFETR 1/8 V V sector model. • Methods and routes of key technologies of CFETR 1/8 V V sector model. • Current manufacturing progress of CFETR 1/8 V V sector model. This paper introduces key technologies and main advances in the development of the 1/8 vacuum vessel (VV) sector mockup of China fusion engineering test reactor (CFETR). The contour accuracy of each VV shell is controlled within ±2 mm through hot forming, solution treatment, and correction of each hyperboloid shell, and cold forming of the single-curved shell. The welding structure between the 1/8 sectors of CFETR VV on site is simulated by using the welding structure between two 1/16 VV sectors as a model. The narrow-gap TIG (NG-TIG) welding process is designed and explored in the sector welding of the 1/32 VV sector. Electron beam (EB) welding of the port stub is completed, and the weld quality meets the design requirement. The results of phased array ultrasonic testing (PAUT) technology reveal that the testing process meets RCC-MR technical requirements and solves the problems of full volume coverage (i.e., missed detection) and signal-to-noise ratio (i.e., misjudgment) of austenitic stainless steel welds. The automatic ray film arrangement trolley can achieve the automatic arrangement of the X-ray film between double shells when the VV is welded on-site. The measurement solution of three-dimensional complex space solves the problem of collimation positioning measurement during the welding, machining, and assembly of the 1/8 VV sector. The results of the study on the virtual assembly and reverse machining technology provide guidance for the actual assembly of the 1/8 VV sector. Finally, measurement and machining of the allowance are realized to solve the problem of numerical control machining of workpieces without a machining datum.