Construction of JT-60SA right on track

Since the last Newsline article on the JT-60SA Tokamak construction activities have proceeded in accordance with the Procurement Arrangements between the two implementing agencies: the Japan Atomic Energy Agency (JAEA) and the European Union's Joint Undertaking for ITER and Development of fusion energy (F4E).

Contracts for the 18 toroidal field coils were signed in December 2010. About 4,400 km of niobium-titanium (NbTi) strand have been approved so far by F4E. Two more batches of toroidal field strand (about 600 km of Cu and 650 km of NbTi in total) were delivered before May to the cabling company. Regarding the toroidal field conductor, the first pre-qualification lengths of 20 m and 97 m have been produced, conditioned and delivered for testing or transformation into samples.

The poloidal field magnet for JT-60SA is composed of six equilibrium field (EF) coils and the central solenoid (CS). A winding module for EF4 to be located in the lowest part of the machine was delivered to the Naka site in April 2012. For the central solenoid, the sixth niobium-tin (Nb3Sn) conductor length (466 m) was manufactured for the first module (CS1); the conductors are now all ready.

After the delivery of the first inboard and outboard segments of the vacuum vessel to the site in Naka, welding of the first 40° sector segments was completed in May 2011 in the vacuum vessel sector assembly building. Following the fabrication of the second 40° sector, the fabrication of the third 40° sector was completed in March 2012.

The manufacture of the cryostat base, which will support the weight of the core components such as superconducting magnets and vacuum vessel, is progressing on schedule. The first lower sector has been assembled and welded within tolerances, and is now in the company´s workshop for machining. The cryostat base will be the first large component to be delivered from Europe to Japan in December 2012.

Disassembly of the JT-60 Tokamak must be completed prior to the delivery of the cryostat base. Removal of the 90-tonne coils made very steady progress, and was completed in March 2012. The 18 coils were reassembled in the form of a torus in the storage building at the Naka site, and will stand as a monument to JT-60 success for future generations.

On 24 April 2012, on the occasion of the 10th meeting of the Broader Approach Steering Committee at the Naka site, representatives of Europe and Japan approved a revised baseline schedule, in line with realistic production schedules and with the first plasma in March 2019. The JT-60SA Research Plan, developed with the cooperation of more than 330 researchers from the European and the Japanese fusion research communities, is in place to ensure a successful joint exploitation of JT-60SA, in support of the operation of ITER and preparations for DEMO.

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