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Publisher Copyright: IEEE In this article, we suggest and study a novel omnidirectional wireless power transfer (WPT) system based on unusual double-toroidal helix coils. The suggested antenna is a double-helix coil wounded around a torus. It creates two mutually orthogonal magnetic fields. One is toroidal and confined inside the torus, and another one is poloidal and is distributed outside it. The intensities of these two fields can be independently tuned via the geometry of the turns. The coupling coefficients are tailored to ensure high efficiency regardless of the receiver position and orientation, without active circuitry for tuning or control. This topology provides self-tuning functionality which is achieved when the coupling between the transmitter and receiver is minimized while the coupling in the pairs transmitter-repeater and repeater-receiver is strong. The system consists of three transmitter-repeater pairs orthogonal to each other, ensuring omnidirectional functionality. Experimental results confirm self-tunability and high efficiency for any position and orientation of receivers. The proposed double-helix antenna is applicable to different WPT applications where the coupling/decoupling between coils can be freely controlled.

The plasma confinement of the International Tokamak Experimental Rector (ITER) is provided by the magnetic field generated by 18 toroidal field (TF) coils while 6 poloidal field (PF) and 6 central solenoid coils have the function to drive, shape and pre-heat the plasma. Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of 10 TF coils and 5 PF coils to the ITER project. The ITER Organization (IO) team is instead responsible for the design of such coils as well for the coordination of the activities of the different Domestic Agencies (DAs) producing the different components, and their assembly into the Tokamak. The PF coils utilize NbTi Cable-in-Conduit-Conductor and have different diameters between 8 and 24 meters and weights of up to 400 tons. Regarding the PF coils produced by F4E, so far one has been completed by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) under a collaboration agreement with F4E. The other 4 PF coils are being produced at the ITER site in Saint Paul lez Durance, France, under F4E supervision. The first of these (PF5) will be completed by July 2020 while the last coil (PF3) will be ready be the end of 2023. The TF coils utilize Nb3Sn conductor and are manufactured with the “Wind, React & Transfer” method. The first TF coil is close to completion and will be delivered to the ITER site in early 2020. Subsequent TF coils will follow at a rate of about one every 3-4 months. In this article we will report on the production status of both PF and TF coils and, in particular, the different manufacturing strategies employed. The main challenges faced so far and the results obtained are also described.

The ITER poloidal field (PF) magnet system is a set of six circular coils attached to the periphery of the toroidal field coil (TFC) structure. While the manufacturing of the PF coils is being launched in three different countries, the ITER Organization (IO) is looking ahead at assembly of PF coils in the tokamak. The PF coils can be grouped in three pairs with respect to their similarities in design and attachment to the TFC, which leads to preparation of different strategies and tooling for the transportation and assembly. The procedures shall also consider the integration, assembly sequence, and environment of the whole tokamak. For example, the two lower coils PF6 and PF5 must be brought in storage position in the tokamak pit and stay there until all the TFCs are assembled, before being attached to them. This paper presents the assembly scenario of the PF coils, including logistics, analysis of assembly tolerances, aligning strategy, and detailing the particularities of each PF coil, from the moment they are delivered to IO until they are connected to the feeder, waiting for the commissioning of the machine.

The Russian Scientific R&D Cable Institute was obliged to produce and to deliver 20% toroidal field (TF) conductors and 20% poloidal field (PF) cables for the ITER magnet system. The task has been completed in October 2015. This work was a great technological challenge in the development of tricky technologies. Development of manufacturing processes was accompanied by extensive scientific studies directed to an improvement of technologies and a search of causes resulting in change of cables and conductors properties during manufacturing and testing. In this paper, we present the extended review and summary of results obtained for Russian superconductors that permitted improving technologies and finding out the reasons of changes of properties of cables and conductors during manufacturing and testing. The study of rotation and untwisting of TF cables during insertions into jackets allowed developing the model describing the rotation process and suggesting the device which keeps untwisting within demanded levels. Analyses of mandatory SULTAN high-field electromagnetic tests of PF and TF conductors from Russia confirmed good quality and adequacy of manufacturing processes. Micrographic studies of Nb 3Sn strands before and after SULTAN tests permitted qualitatively understanding the reason for the stability of RF TF conductor behavior during multiple electromagnetic and thermal cycling. Statistical studies of residual resistance ratio (RRR) of Nb 3Sn and NbTi strands permitted tracking of its degradation during manufacturing processes and SULTAN tests. The optimal heat treatment process for Nb 3Sn conductors has been confirmed after RRR statistical study. The hydraulic performance has been measured in the short samples of TF conductor. By using the parameters obtained, it is possible to predict hydraulic performance of helium flow in a conductor at any temperature. These results led to deeper understanding and to improving manufacturing processes and quality of TF and PF conductors for the ITER magnet system and could be useful for suppliers of superconducting cables and conductors using ITER-like technologies.

This chapter deals with the design concepts of power supply systems (PSSs) for energising the magnet systems of tokamaks, as well as with the main problems arising in the course of their development and the approaches to solutions of these problems. The peculiarities of the requirements imposed on the PSSs of two main groups of the magnet system’s coils, which have essentially different functions, namely, the toroidal field and poloidal field coils, are considered. Particular attention is given to the description of the means for the protection of the superconducting coils. The last section describes high-current switching devices used for initiation of plasma discharge and for emergency extraction of energy from magnet systems in case of coil superconductor-to-normal transition. The focus is on the switches, superior to commercial products in the key parameters, developed at the Efremov Institute in the framework of the ITER project.

China International Nuclear Fusion Energy Program Execution Center (ITER China), the China Domestic Agency for ITER, is in charge of about 7.51% of the Toroidal Field (TF) conductors, 65.15% of the Poloidal Field (PF) conductors, namely 11 TF conductors and 60 PF conductors. All those conductors are supplied in-kind by ITER China. Following success in qualification test on full-scale short conductor samples, ITER China is stepping into the series production of the TF and PF super conductors. Several tons of Nb3Sn and NbTi strands were manufactured, tested, and delivered from strands supplier to assembling supplier under the supervision of the ITER China and all the conductor manufacture processes complied with ITER quality assurance requirements. This article reports the progress on TF and PF conductor of ITER China up to December 2012.

The ITER correction coils (CCs) are designed to be arranged toroidally around the machine inside the poloidal field coils and mounted on the toroidal field coils in order to compensate field errors arising from misalignment of the coils and winding deviations from the nominal shape as a result of fabrication tolerances, joints, leads, busbars CCs, and assembly tolerances. China is responsible for manufacturing all the CCs and their conductor. The paper presents the qualification progress and results of ITER CCs and CC conductor, including the test results of CC SULTAN samples, double pancakes winding experiments, CC case welding techniques, and manufacturing experiment of CC helium inlet/outlets.

KSTAR has a nonlinear magnetic material, INCOLOY® alloy 908 (Incoloy), in toroidal field and poloidal field (PF) coil systems. The effect of Incoloy on the magnetic configuration for the plasma ini...