JT-60SA: The Tokamak assembly begins

There has recently been much excitement in Naka concerning JT-60SA, the “satellite” facility of ITER to model proposals for optimising plasma operation and investigate advanced plasma modes that could be tested on ITER or used later on DEMO. On 28 January, the Tokamak assembly began with the cryostat base (CB), the first major component to be delivered by Europe. This marks a very important step forward for the project, which is part of the Broader Approach Agreement signed between Japan and Euratom (The European Atomic Energy Community) and implemented by JAEA and Fusion for Energy (F4E).

The CB, which supports the weight of the entire Tokamak, has a diameter of 12 metres, a height of 3 metres and weighs 250 tonnes. It consists of a double ring in three sectors, a lower structure in three sectors, and an inner cylinder and is assembled using connecting bolts. The manufacturing of the CB was carried out in Aviles, Spain, by IDESA and final machining and pre-assembly was done by ASTURFEITO, under the supervision of CIEMAT.

Anticipation started building already in November 2012 with the final pre-assembly of the CB at the manufacturer’s facilities. An accurate dimensional tolerance check was performed with a 3D portable laser tracker, and results proved to be satisfactory with low error under the limits.

By 8 November, the manufacture was completed and all parts of the CB were packed for transport. Due to their large size (maximum width 6.5 m), the pieces were difficult to transport, especially by road, but fortunately the factories where the CB was fabricated and machined were close to one another as well as to the Aviles seaport.

Fagioli, contracted to F4E, managed all aspects of the transport up to the port of entry in Japan. The CB was collected from the factory on 12 November and transported to the Aviles port. After loading the CB on board, the ship “IYO” set sail on 22 November, took on further cargo at other European ports, and then headed across the Atlantic and Pacific Oceans via the Panama Canal. After the 18,000 km long sea voyage, the CB finally arrived at Hitachi port in Japan on 16 January 2013.

The transport from Hitachi port to the Naka Fusion Institute was conducted by JAEA in seven stages during the week starting on 19 January. Transport was carried out before dawn on closed roads. All seven pieces of the cryostat base were delivered to the assembly hall at the Naka Fusion Institute by 26 January.

Tokamak assembly began on 28 January. The start was open to the press, and reporters from 10 media organisations were able to witness the real assembly work. This event was widely reported to the public through newspapers, web, and TV, including the national news.

This timely start to the assembly of the JT-60SA Tokamak is the beginning of a 6-year assembly and commissioning period which will enable the first plasma to be achieved in March 2019, ready for this project’s role to support and complement ITER.