P. Barabaschi

Progress of the JT-60SA project

The JT-60SA project implemented by Japan and Europe is progressing on schedule towards the first plasma in March 2019. After careful R&D, procurements of the major components have entered their manufacturing stages. In parallel, disassembly of JT-60U has been completed on time, and the JT-60SA tokamak assembly is expected to start in January 2013. The JT-60SA device, a highly shaped large superconducting tokamak with a variety of plasma control actuators, has been designed in order to contribute to ITER and to complement ITER in all the major areas of fusion plasma development necessary to decide DEMO reactor construction. Detailed assessments and prediction studies of the JT-60SA plasma regimes have confirmed these capabilities: using ITER- and DEMO-relevant plasma regimes, heating conditions, and its sufficiently long discharge duration, JT-60SA enables studies on magnetohydrodynamic stability at high beta, heat/particle/momentum transport, high-energy ion physics, pedestal physics including edge localized mode control, and divertor physics. By integrating these studies, the project provides ‘simultaneous and steady-state sustainment of the key performance characteristics required for DEMO’ with integrated control scenario development.

Overview of the JT-60SA project

This paper overviews the achievements and plans of the JT-60SA project which has been implemented jointly by Europe and Japan since 2007, covering the objectives, performance, schedule, design and procurement activities and on-site preparations. Re-baselining of the project was completed in late 2008. All of the scientific missions are preserved with the newly designed machine to meet the cost objectives. The construction of the JT-60SA has begun with procurement activities for components of the toroidal field magnet, poloidal field magnet, vacuum vessel, in-vessel components, cryostat, power supplies in parallel with dismantling the JT-60 facilities, at the end of which the first plasma is foreseen in 2016. For exploitation, development of the JT-60SA research plan has been started jointly between Japan and Europe.

Design of the JT-60SA Superconducting Toroidal Field Magnet

The JT-60SA is a fusion experiment designed to contribute to the early realization of fusion energy, by providing support to the operation of ITER, by addressing key physics issues for ITER and DEMO and by investigating how best to optimize the operation of the next fusion power plants that will be built after ITER. It is a combined project of the JA-EU Satellite Tokamak Program under the Broader Approach (BA) Program and JAEAs Program for National Use, and it is to be built in Naka, Japan, using the infrastructure of the existing JT-60U experiment. This paper describes in detail the design of the JT-60SA Toroidal Field magnet and shows the strong points of each foreseen solution. Additional information about manufacturing procedures is given and technological issues are reported and critically analysed.

A Stepped Approach from IFMIF/EVEDA Toward IFMIF

Abstract In this paper we analyze from the technical point of view the possibility of developing the IFMIF facility (International Fusion Materials Irradiation Facility) in a stepped approach from the prototypes, presently under testing in the framework of the IFMIF/EVEDA Project (IFMIF Engineering Validation and Engineering Design Activities), but with the capability to fulfill the DEMO (Demonstration reactors) needs in a first step and the fusion power plant needs in a second step. The paper is focused on the so-called DONES (DEMO Oriented Neutron Source) alternative. It is built using one of the 40 MeV IFMIF accelerators, together with a strong simplification of some of the other systems and subsystems, driven by the lower power to be handled in the DONES facility, by transferring the PIE (post-irradiation experiment) analysis to other external facilities, by reducing the remote handling activities foreseen in the facility, and by reducing the type of irradiation experiments to be performed simultaneously. A preliminary neutronic evaluation of the achievable radiation map and on the requirements for the transfer of the irradiated modules to the external facility is also presented.

The Manufacturing of the Superconducting Magnet System for the JT-60SA

JT-60SA is the satellite tokamak for ITER in the Broader Approach agreement. The JT-60SA uses 18 toroidal field coils, a central solenoid with 4 modules, and 6 equilibrium field coils, they are all superconducting coils with forced flow cooled conductors. All detailed designs of these superconducting coils have been completed. The manufacturing of conductors and coils are progressing in Japan and EU. This paper shows the latest manufacturing activities and final design adjusting of its magnet system and their utilities.

The JT-60SA Toroidal Field Conductor Reference Sample: Manufacturing and Test Results

In the framework of the JT-60SA design activities, EU home team has defined a reference layout for the Toroidal Field conductor: it is a slightly rectangular Cable-In-Conduit NbTi conductor, operating at 25.7 kA with a peak field of 5.65 T. ENEA has assigned LUVATA Fornaci di Barga the task to produce the strands and to perform cabling, whereas jacketing and compaction have been carried out in its own labs. The sample, successfully tested at the CRPP SULTAN facility, has been assembled in such a way as to avoid the bottom joint between the two legs, thus using a single conductor length (about 7 m). An ad-hoc developed solution to restrain the U-bent conductor section (where jacket is not present), consisting in a stainless steel He-leak tight box with an inner structure designed in order to completely block the cable, has been also developed and manufactured by ENEA, where the sample has been also assembled. Instrumentation installation and final assembly of the sample have been performed by the SULTAN team. The main aspects of the sample manufacturing and characterization are here presented and discussed.

Completion of TF Strand Production and Progress of TF Conductor Manufacture for JT-60SA Project

In the framework of the JT-60SA project, aiming at upgrading the present JT-60U tokamak, Europe, as part of its in-kind contribution within the Broader Approach agreement, will provide the toroidal field (TF) magnet system. For this purpose, Fusion for Energy is committed to procure about 29 km of TF conductor. The TF conductor is cable-in-conduit type and includes 486 strands (2/3 NbTi-1/3 copper) wrapped with a thin stainless steel foil and compacted into a rectangular stainless steel jacket. The procurement is split into two main contracts: one for TF strand manufacturing and the other for TF conductor cabling and jacketing. TF strand manufacture was completed while the TF conductor one is being finished. In the present paper, we draw an overview of both productions emphasizing on the quality control (QC) approaches and on aspects relevant to risk management of the JT-60SA tokamak operation. For the NbTi strand, the complete production overview is provided including extensive statistical considerations on NbTi strand critical performances ( IC, TCS). For the TF conductor, the overview also deals with collected results from acceptance tests and peripheral tests led for consolidating the QC (hydraulic tests, nondestructive examination, full-size sample cold tests in SULTAN facility).

Starting EU Production of Strand and Conductor for JT-60SA Toroidal Field Coils

Included in the Broader Approach (BA) treaty, the JT-60SA project foresees to upgrade the existing JT-60U tokamak by substituting superconducting magnets to the present resistive magnets system. For this, a bilateral EU-JA procurement agreement drives EU, represented by Fusion for Energy (F4E) entity, to procure in-kind the totality of the 18 JT-60SA Toroidal Field (TF) Coils. Being almost the totality of the in-kind procurement of F4E for JT-60SA, the TF conductor manufacture monitoring is directly held by F4E, finalized by a delivery of components to collaborative EU institutes (CEA and ENEA) for its transformation into TF coils [1]. The organization of TF conductor procurement lies on two con- tract placed in December 2010 by F4E to industrial operators for strand manufacture on one side and cabling - jacketing transformation on the other side. After a general overview the present paper describes the different steps reached up to the present state of fabrication achievement. The status of the ongoing manufacture and the foreseen next steps targeted in the near future will also be mentioned.

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.

Tests and Analyses of Two TF Conductor Prototypes for JT-60SA

In the framework of the JT-60SA project, included inside the Broader Approach agreement, EU is expected to provide to JA the totality of the toroidal field (TF) magnet system. It consists in 18 coils, evenly shared for in-kind procurement between France and Italy while the TF conductor providing is under the responsibility of Fusion for Energy. The conductor is a rectangular-shaped, NbTi-based, cable-in-conduit (CICC) and will be wound in double-pancake inside the TF casing. In the paper, the experimental approach of conductor design validation process and the associated analyses of conductor samples test campaign in the SULTAN facility are shown. A design and manufacture action on full-size SULTAN-type short samples for the TF conductor have been launched in 2007 to allow an early gathering of relevant information enabling to proceed onto the conductor design qualification process. A series of two pre-prototypes was realized, based on a former conductor design which even if slightly different from the most up-to-date layout, includes all its important relevant features: square-shaped section, superconducting strands segregation with copper, no subwrapping. The samples are designed to allow comparative studies on shape influence (two types of sections) and on joint influence (presence or not of a bottom joint), and to provide a consolidated baseline for making decisions on conductor final design. A descriptive part of the samples manufacturing activity is included. The samples TFCS1 and TFJS1 were then characterized in the SULTAN facility (Villigen, CH) respectively in 2008 and 2009, experiencing DC tests, AC tests, mechanical cycling, and stability tests. The corresponding results and the associated analyses are shown and statements regarding the contribution of the present results to the assessment of the actual JT-60SA TF conductor design are also drawn.