ITER PF6 double pancakes stacking

• Published in: Fusion engineering and design 2019-10, Vol.147, p.111240, Article 111240
• Main Authors: Zheng, Xingdong, Wen, Wei, Shen, Guang, Hu, Bing, Sborchia, Carlo, Readman, Peter, Wu, Weiyue, Gu, Yongqi
• Format: Article
• Language: English
• Subjects: Coils (windings); Concentricity; Double pancake; Field coils; Joint; Laser beam welding; Magnets; Nuclear power plants; PF6 coil; Plasma physics; Soldering; Stacking; Thermal stress; Tooling
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2019.111240

•The stacking of ITER PF6 double pancakes was successfully accomplished with dimensions well met the requirements from ITER IO.•To eliminate the thermal stress during inter-pancake joint copper sole soldering, the DP being stacked was lifted up to 80–90% of its weight to allow free rotating and moving.•The concentricity between winding pack after DPs stacking and winding pack VPI mould was 0.99 mm, which was a good foundation for ground insulation wrapping and VPI. The Poloidal Field (PF) coils are one of the main sub-systems of the ITER magnets. The PF6 coil is being manufactured by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) as per the Poloidal Field coils cooperation agreement signed between ASIPP and Fusion for Energy (F4E). ITER PF6 winding pack (WP) is composed by 9 double pancakes (DPs). After the vacuum pressure impregnation (VPI) of each DP, the 9 DPs were stacked together and inter-pancake joints were manufactured to form the WP. This paper focus on the main process of ITER PF6 DPs stacking. During stacking, the DP being stacked was firstly been placed in position by means of vacuum pads lifting system, laser tracker and stacking guiding tooling. To eliminate the thermal stress, the DP being stacked was then lifted up to 80–90% of its weight to allow free rotating and moving while inter-pancake joints copper sole soldering. At the end, the DP being stacked was released, followed by welding of lateral plates and wedges. The DPs stacking has been finished with an overall concentricity of less than 1 mm and toroidal positioning of less than 5 mm for each DP, which well met the technical requirements.