A. Cucchiaro

JT-60SA Toroidal Field Magnet System

The broader approach agreement between Europe and Japan includes the construction of a fully superconducting tokamak, the JT-60 Super Advanced (JT-60SA), as a satellite experiment to ITER. In particular, the whole Toroidal Field magnet system, described in this paper, will be provided to Japan by the EU. All the TF coil main constituents, i.e. conductor, winding pack, joints, casing, current leads, are here presented and discussed as well as the design criteria adopted to fulfil the machine requirements. The results of the analyses performed by the EU and JA to define and assess the TF magnet system conceptual design are reported and commented. Future work plan is also discussed.

Mass Production of Superconducting Magnet Components for JT-60SA

JT-60SA is foreseen in the Broader Approach Agreement as the satellite tokamak for ITER. It uses 18 toroidal field coils, a central solenoid with four modules, and six equilibrium field coils. The coils are all superconducting with forced-flow cooled conductors. Series production of conductors and coils is progressing in Japan and Europe. This paper shows the latest manufacturing activities of the magnet system and its utilities.

Design of JT-60SA Magnets and Associated Experimental Validations

In the framework of the JT-60SA project, aiming at upgrading the present JT-60U tokamak toward a fully superconducting configuration, the detailed design phase led to adopt for the three main magnet systems a brand new design. Europe (EU) is expected to provide to Japan (JA) the totality of the toroidal field (TF) magnet system, while JA will provide both Equilibrium field (EF) and Central Solenoid (CS) systems. All magnet designs were optimized trough the past years and entered in parallel into extensive experimentally-based phases of concept validation, which came to maturation in the years 2009 and 2010. For this, all magnet systems were investigated by mean of dedicated samples, e.g. conductor and joint samples designed, manufactured and tested at full scale in ad hoc facilities either in EU or in JA. The present paper, after an overall description of magnet systems layouts, presents in a general approach the different experimental campaigns dedicated to qualification design and manufacture processes of either coils, conductors and electrical joints. The main results with the associated analyses are shown and the main conclusions presented, especially regarding their contribution to consolidate the triggering of magnet mass production. The status of respective manufacturing stages in EU and in JA are also evoked.

A New Design for JT-60SA Toroidal Field Coils Conductor and Joints

The upgrade of JT-60U to JT-60 Super Advanced (JT-60SA), a fully superconducting tokamak, will be performed in the framework of the Broader Approach (BA) agreement between Europe (EU) and Japan. In particular, the Toroidal Field (TF) system, which includes 18 coils, is foreseen to be procured by France, Italy and Germany. This work covers activities from design and manufacturing to shipping to Japan. The present paper is mainly devoted to the analyses that lead to the conductor design and to the technical specifications of the joints for the JT-60SA TF coils. The conductor geometry is described, which is derived from Cable-In-Conduit concept and adapted to the actual JT-60SA tokamak operating conditions, principally the ITER-like scenario. The reported simulations and calculations are particularly dealing with the stability analysis and the power deposition during normal and off-normal conditions (AC losses, nuclear heating). The final conductor solution was selected through a trade-off between scientific approach and industrial technical orientation. Besides, the TF system connections layout is shown, derived from the industrially assessed twin-box concept, together with the associated thermo-hydraulic calculations ensuring a proper temperature margin.

Manufacturing of the Casing Components for the JT-60SA Toroidal Field Coils

The JT-60SA superconducting tokamak is being constructed in Japan under the Broader Approach agreement between Japan and the EU. ENEA is responsible for the in-kind supply of 18 toroidal field coil casings for JT-60SA, and contracted the company Walter Tosto (Chieti, Italy) for fabrication of two sets of nine casings each to be delivered to the coil manufacturers ASG Superconductors (Genoa, Italy) and Alstom (Belfort, France). After the completion of the detailed design of the casing components stainless-steel materials were acquired and the manufacturing processes were qualified on mock-ups representative of the components. The complete resolution of all design and technical issues required the replacement of the forged stainless-steel material and a revision of the time schedule. On the basis of the manufacturing experience of the first two different sets of casing components, the production process has been improved, and the fabrication of the complete procurement is now ongoing. This paper reviews the main steps of the fabrication of the casing components, highlighting the critical issues encountered and reporting the status of the manufacturing activities.

Construction Status of the Superconducting Magnet System for JT-60SA

The construction of the JT-60SA tokamak is one of the three projects of the Broader Approach activities being undertaken jointly by Japan and Europe. The superconducting magnet system for JT-60SA consists of 18 toroidal field coils, a central solenoid with four modules, six equilibrium field coils, superconducting feeders, high-temperature-superconductor current leads, thermal shields, and the cryogenic system. This paper shows the latest construction activities of the superconducting magnet system.

Status of the JT-60SA magnet system

The JT-60SA experiment will be the worlds largest superconducting tokamak when it is assembled in 2019 in Naka, Japan (R=3m, a=1.2m). The superconducting magnet system includes 18 D-shaped toroidal field coils, each 7m high and 4.5m wide, 6 pulsed equilibrium field coils up to 12m in diameter and 4 central solenoid modules. Manufacturing of the superconducting magnets for JT-60SA is well established in Japan and in Europe. Conductor manufacturing is almost complete, half of the superconducting coils have been wound and the first cold test results for production coils will be available later in 2015. Challenges remain to integrate the coils with their mechanical structures and to assembly them into the tokamak.

Manufacturing Status of JT-60SA Toroidal Field Coils

The 18 D-shaped Nb-Ti toroidal field (TF) coils for the JT-60SA tokamak will each be 7 m high and 4.5 m wide. Together they will generate an on-axis field of 2.25 T. All the main contracts for their manufacture are now in place, with manufacturing split primarily between sites in Japan (superconducting strand), Italy (conductor cabling and jacketing, casings fabrication and coil winding, and integration), and France (support structures, coil winding and integration, and final coil cold testing). This paper will summarize the key aspects of the design of the coils and the current status of manufacture on each area of the manufacture of the TF coils. A simple overview of the overall schedule for their completion is included.

Toroidal field coil thermal analysis for fast tokamak

A new facility for fusion, the Fusion Advanced Studies Torus (FAST), has been proposed to prepare ITER scenarios and to investigate non linear dynamics of energetic particles, relevant for the understanding of burning plasmas behavior, using fast ions accelerated by heating and current drive systems [1]. This new facility is considered an important tool also for the successful development of the demonstration/prototype reactor (DEMO), because the DEMO scenarios can take valuable advantage by a preparatory activity on devices smaller than ITER with sufficient flexibility and capable plasma conditions, before to testing them on ITER itself.

First Italian JT-60SA TF coil winding pack preliminary insertion into casing

In the framework of the Broader Approach Agreement between Europe and Japan for the construction of the JT-60SA tokamak in Naka, Japan, ENEA is committed to supply nine toroidal field (TF) superconducting magnets. The supply is carried out via a contract awarded in 2011 to ASG Superconductors, in which all the qualification activities have been accomplished and the manufacturing has already considered every step of fabrication. Six of the foreseen winding packs (WP) have been already wound, vacuum pressure impregnated and tested; the subsequent phase of the fabrication, consisting in the into casing insertion of the WP, has started. The critical processes have been qualified through the use of dedicated mock-ups. To carry out the insertion operation a dedicated tooling has been designed and installed in ASG. It consists of a central core on which the WP is grasped and of two lateral carriages for the casing component approaching in horizontal position. The present paper describes the WP manufacturing process highlighting some issues as the dimensional tolerances and the electrical insulation under vacuum. The final phase of fabrication, consisting in the into casing insertion of the WP, will be reported describing all the steps to arrive at the completion of the first TF coil.