Fusion Engineering and Design 55 (2001) 153 – 170 ITER R&D: Magnets: Central Solenoid Model Coil H. Tsuji a , S. Egorov b , J. Minervini c , M. Martovetsky d , K. Okuno e , Y. Takahashi a, *, R.J. Thome f a Superconducting Magnet Laboratory, Japan Atomic Energy Research Institute, 801 -1 Mukouyama, Naka -machi Naka -gun, Ibaraki -ken 311 -0193, Japan b D.V. Efremo Scientific Research, Institute of Electrophysical Apparatus, Scientific Technical Center ‘SINTEZ’, Metallostroy, Soetsky pr. 1, St. Petersburg 196641, Russia c MIT, 185 Albany Street, NW 22 -129, Cambridge, MA 02139, USA d LLNL, L-641, 7000 East Aenue, Liermore, CA 94550, USA e ITER Naka Joint Work Site, 801 -1 Mukouyama, Naka -machi Naka -gun, Ibaraki -ken 311 -0193, Japan f General Atomics, 3550 General Atomics Ct. Building 13 -167, San Diego, CA 92186 -5608, USA www.elsevier.com/locate/fusengdes 1. Introduction The central solenoid (CS) model coil is composed of an inner module with ten layers and an outer module with eight layers as shown in Fig. 1. In addition, two single-layer insert coils are being developed and fabricated, one to provide detailed testing of the CS conductor (the CS insert) and one to test the TF conductor (the TF insert). These insert coils are placed in the bore of the CSMC for testing. The CS insert coil was tested in May–Au- gust, 2000 and the coil has since been removed from the facility. The TF Insert Coil with the full-size conductor of the TF coils has been fabricated and testing is expected to be carried out in September 2001. Each layer of the main coil was formed from two lengths of conductor, wound two in hand. The inserts are made with a single unit length. The winding process followed a wind – heat treat – insu- late – impregnate procedure, where the Nb 3 Sn su- perconductor was formed after the winding process but was then subjected to limited elastic deforma- tions (an ‘unspringing’ of the conductor spiral) to allow Kapton – glass insulation to be applied. The layers were assembled together from the inside out. Joints were placed on top and bottom of the coil, at the end of a curved length of conductor that transitions from the winding to the vertical direc- tion to allow space for joint assembly. The support of this transition length and the joints themselves requires a complicated support structure built up of shaped epoxy-glass blocks and local tie plates of incoloy, known as the buffer zone. The inner module of the coil was fabricated by Lockheed Martin under the supervision of USHT, the outer module by Toshiba under the supervision of JAHT. The CS insert was produced by Mit- subishi (JAHT) and the TF insert by the Efremov Institute, RFHT. The CSMC and CS insert used incoloy conductor supplied through a collaborative activity between all the ITER HT, as shown in Fig. 2. In summer 2000, the CSMC was operated suc- cessfully at a current of 46 kA, and a magnetic field of 13 T, giving a stored magnetic energy of * Corresponding author. Tel.: +81-29-270-7776; fax: +81- 29-271-7507. E-mail address: takahasi@naka.jaeri.go.jp (Y. Takahashi). 0920-3796/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0920-3796(01)00204-6