Progress of ITER TF Coil Fabrication in Japan

Iguchi, Masahide; Sakurai, Takeru; Hemmi, T.; Fujiwara, Eikou; Ino, Masanobu; Nishino, Masao; Tanaka, Nobuhiko; Kanamori, S.; Kurita, Tomohisa; Hanaoka, Toshiaki; Hong, Yun-Seok; Tsutsumi, F.; Nakahira, Masataka; Koizumi, N.

doi:10.1109/tasc.2020.2971673

Cited by 10 publications

(9 citation statements)

References 5 publications

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“…The change in the CCL positions need to be calculated from the change in WP position plates measurements. The evaluation utilizes mechanical simulation 7) inputting displacements of WP position plates as imposed displacements to calculate the corresponding displacements at the CCL positions of WP. The WP model in structural analysis is prepared considering the material compositions and their properties.…”

Section: Closure Weldingmentioning

confidence: 99%

Development of ITER TF Coil Assembly Technique, Integration of Winding Pack into Coil Case

et al. 2020

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The ITER Toroidal Field (TF) coil is a D-shaped superconducting magnet. A set of 18 TF coils forms a donut shape when assembled around the ITER vacuum vessel. The magnetic property of a coil is characterized by a current center line (CCL). To serve their function as plasma containment magnets, severe requirement of φ2.6 mm cylindrical tolerance is defined for the critical portion of the TF coils. In previous study, the manufacturing tooling and procedure have been developed and applied for manufacturing of Winding Packs (WP) and TF Coil Case (TFCC) subassemblies. In integration of a WP into a TFCC, predetermined CCL of the WP shall be controlled and transferred to reference points of the TFCC. For precise control of the CCL positions, deformations of the WP and the TFCC must be controlled. Also, the precise tracking of the CCL position required some techniques to evaluate the CCL positions even after the WP is completely covered by the TFCC. Techniques have been developed through welding trials and structural simulation analysis. Those techniques are applied to TF coil production and two TF coils have been completed successfully.

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Section: Closure Weldingmentioning

confidence: 99%

Development of ITER TF Coil Assembly Technique, Integration of Winding Pack into Coil Case

et al. 2020

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“…10). The resin is initially injected from the lowest inlets of the TFCC; when the resin level reaches the level of the next inlets, valves to those inlets are also opened 7) . By changing the inlet positions according to the resin level, the low viscosity is maintained at the resin front.…”

Section: Conclusion From Narrow Gap Qualification Testsmentioning

confidence: 99%

“…For balancing the pressure difference over the gap seal, stainless-steel structures to enclose the whole cooling pipe penetration parts and the whole terminal region were designed 7) . By adjusting the pressure inside this terminal cover to the same pressure inside the TFCC, the pressures on the both sides of the terminal region can be maintained at the equilibrium.…”

Section: Conclusion From Pressure Qualification Testmentioning

confidence: 99%

“…Joule heating of conductors controlled the temperature of the WP, while the temperature of the TFCC is controlled by flowing temperature-controlled water through its internal cooling pipes 7) . Since the both components are mainly made of stainless steel, the temperature difference shall be maintained below 2.5℃ to keep the differential thermal expansion less than 300 μm during resin injection.…”

Section: Procedures and Instrumentsmentioning

confidence: 99%

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Development of Gap-filling Impregnation Method of ITER TF Coils

et al. 2020

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The ITER Toroidal Field (TF) coil is composed of a Winding Pack (WP) and a TF coil case (TFCC). In the manufacturing of a TF coil, the gap between the WP and the TFCC is filled with radiation resistant Triglycidyl-p-aminophenol (TGPAP) resin. Vacuum Pressure Impregnation (VPI) is adopted. The selected resin system displayed two potential problems: high viscosity and cracking after cure. A series of production optimizations have been performed to develop techniques to apply the selected resin for the TF coil production: crack countermeasure, narrow gap injection, and pressure control. For crack countermeasure, the addition of fiberglass tape or sheet layer was found to be effective in preventing fragmentation of cracked resin. Since the cracked resin would not harm the TF coil quality as long as it stays in the original position, addition of confining fiberglass layers solves the problem. In narrow gap qualification tests, resin injection into a 2 mm wide space was observed with proper selection of fiberglass layer addition conditions. The pressure qualification test showed that resin cured without additional pressurization can satisfy the compression strength requirements. From those results, techniques for the TF coil production have been developed, and with the implementation of those techniques the gap-filling of the first TF coil in Japan was successfully completed in 2019. Since then, two more TF coils have completed the gap-filling process with some improvements.

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“…Procedure of the TF coil integration [4] is as follows, (1) half of CC with opened surface is placed on the floor with its inner board facing down, (2) WP is inserted into the CC, (3) another half of the CC with opened surface is placed over the WP, (4) interface of the two halves of CC is welded, (5) opened surface of the CC is closed with plates (closure welding), (6) the gap between CC and WP is filled with epoxy resin (gap filling). During the TF coil integration process, current center line (CCL) is controlled with accuracy of 1.3 -3.0 mm [4,7]. It is possible to geometrically author's e-mail: hasegawa.shin2@qst.go.jp * ) This article is based on the presentation at the 31st International Toki Conference on Plasma and Fusion Research (ITC31).…”

Section: Introductionmentioning

confidence: 99%

A Double Check Process for CCL Positional Plates in ITER TF Coil Integration

HASEGAWA

TSUTSUMI

SAITO

et al. 2023

Plasma and Fusion Research

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A current center line (CCL) was precisely controlled with markers called "CCL positional plates (CCLPPs)" during the ITER toroidal filed (TF) coil integration. CCLPPs with the same x and y coordinates (CCLPP pair) are attached on both sides of the TF coil Winding Pack (WP). The CCLPP insufficiently fixed has to be replaced with new one to ensure the accuracy of CCL. On the other hand, the replacement possibly leads to some issues, such as, dropping the CCLPP into the CC and damaging the WP. Thus, unnecessary replacement should be avoided. We have therefore implemented a double check process to confirm soundness of the CCLPPs. First, change of the distance of CCLPP pair (∆W CCLPP ) is evaluated (Check A). However, ∆W CCLPP would be influenced by the WP deformation. Thus, the Check A possibly judges the fixing condition of the CCLPP as "unusual" even if it has no issue. This may lead to the unnecessary replacement of the CCLPP. To avoid the unnecessary replacement, the local displacement of each CCLPPs (∆r CCLPP ) is also evaluated (Check B). In this paper, we define the criteria for "unusual" ∆W CCLPP and ∆r CCLPP based and verify its validity for the TF coil integration by considering the measurement error and geometrical configuration of the CCLPPs. In the case of one Toshiba TF coil, the double check process confirmed that CCLPPs were insufficiently fixed, and they were successfully replaced to the new ones. Thus, it was demonstrated that the proposed criteria indicated the appropriate action to keep the CCLPP soundness. The method proposed in this paper would be powerful tool to inspect the soundness of the CCLPP which is important for the CCL control not only in the ITER TF coil, but also in the future fusion magnets.

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Progress of ITER TF Coil Fabrication in Japan

Cited by 10 publications

References 5 publications

Development of ITER TF Coil Assembly Technique, Integration of Winding Pack into Coil Case

Development of ITER TF Coil Assembly Technique, Integration of Winding Pack into Coil Case

Development of Gap-filling Impregnation Method of ITER TF Coils

A Double Check Process for CCL Positional Plates in ITER TF Coil Integration

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