Speaker
Dong Kwon Kang
(ITER Korea)
Description
Thermal shield (TS) is one of the components in the ITER tokamak to minimize radiation heat load from vacuum vessel and cryostat to magnet structure that operates at 4.5 K. The TS main components (TSMC) are vacuum vessel TS (VVTS), cryostat TS (CTS) and support TS (STS). The TSMC are cooled by 80 K helium gas, which is supplied from the cryoplant via manifold pipes. The surface emissivity of the TSMC must be maintained under 0.05 by silver coating. ITER TS is being fabricated by the Korean supplier, SFA. The fabrication of all the nine 40 degree VVTS sectors are on-going since the start of material buffing in October 2014. Fabrication of VVTS proceeds according to the following processes: 1) material buffing, 2) plate cutting, 3) bending and forming, 4) 2ndnd buffing, 5) welding, 6) flange final machining, 7) pre-assembly of 40 degree sector, 8) final buffing, 9) silver coating, 10) final acceptance test. All VVTS shell segments are to be assembled by the flange joints, which are welded to the shells. Therefore tolerance requirement of the flange is strict for successful assembly of entire VVTS torus shape. Several pre-qualifications were performed prior to the manufacturing processes. All the welding joints were validated by non-destructive examinations and the inner surface of the welded cooling tube on The VVTS panel was inspected by a novel endoscope. Vacuum leak test was also performed in the test vacuum chamber. Currently, final machining of first delivery sectors (#6 and #5) was completed and the remaining works are pre-assembly of 40 degree sector and silver coating. Dimensional inspection method for the pre-assembled 40 degree VVTS sector and silver coating qualification method are briefly introduced in this paper. Lessons learned during the manufacturing of VVTS are also summarized.
Co-authors
Chang Hyun Noh
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Chang-Ho Choi
(ITER Organization, Saint-Paul-lez-Durance, France)
Dong Kwon Kang
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Hyeon Gon Lee
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Ki-Jung Jung
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Kisuk Lim
(SFA Engineering Corp., Asan, South Korea)
Kwanwoo Nam
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Kyoung-O Kang
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Manoj Panchal
(ITER Organization, Saint-Paul-lez-Durance, France)
Nam Il Her
(ITER Organization, Saint-Paul-lez-Durance, France)
Wooho Chung
(ITER Korea, National Fusion Research Institute, Daejeon, South Korea)
Youngkil Kang
(SFA Engineering Corp., Asan, South Korea)
