The first of five vacuum vessel sectors for the International Thermonuclear Experimental Reactor (ITER) under construction at Cadarache in France to be supplied by Fusion for Energy (F4E) is undergoing factory acceptance tests. The component has already passed leak testing and its dimensions will now be checked.
The fabrication of the vacuum vessel sectors is shared between F4E, Iter Organisation's European domestic agency (five sectors) and the Korean Domestic Agency (four sectors). ITER's vacuum vessel (plasma chamber), with an interior volume of 1,400 cubic metres, houses the fusion reactions and is the first safety containment barrier. It will comprise nine wedge-shaped steel sectors each more than 14 metres high and weighing 440 tonnes. Vacuum vessel sector No. 6, which is at the centre of the assembly and is associated thermal shielding, has already been manufactured and delivered by Korea.
The ITER vacuum vessel, once assembled, will have an outer diameter of 19.4 metres, a height of 11.4 metres, and weigh approximately 5,200 tonnes. Installation of in-vessel components such as the blanket and the divertor will increase the weight to 8,500 tonnes.
The first sector to be supplied by Europe (No. 5) has now been manufactured at the Westinghouse/Mangiarotti facility in Monfalcone, Italy, and is undergoing factory acceptance tests before being shipped to the construction site. F4E said years of teamwork in developing the procurement strategy, agreeing on the design, the technical specifications, and following up its manufacturing, “have come down to this make-or-break moment in the lifecycle of the component”. F4E added: “The valuable lessons learnt from sectors delivered by Korea, and the knowledge accumulated from the collaboration between F4E and the AMW consortium (Ansaldo Nucleare, Mangiarotti and Walter Tosto) have fed into this exercise." tests consist of hydraulic and dimensional checks.
Hydraulic testing of sector No. 5 was completed in January. F4E said the results were "solid proof that the welding, assembly and manufacturing met the highest standards". The tests used nitrogen and helium to examine the response to pressure and vacuum to ensure that there were no leaks in the structure. "Checking these parameters is of paramount importance because the fusion reaction requires an environment which is completely tight," F4E noted. "Furthermore, the vacuum vessel is classified as a nuclear component that needs to comply with the strict prerequisites set by the French Nuclear Safety Authority."
Joan Caixas, F4E Assembly Project Manager attributed the successful outcome of these operations to years of cooperation between F4E, ITER Organisation and AMW. "The results give us a lot of confidence for the next tests and ultimately for the delivery of Europe's first sector," she noted. These dimensional tests will need more time given the volume of the component. They will accurately measure the component using sophisticated probes, lasers, and other tooling to scan the surface, spot any deformations, etc.
When the factory acceptance tests are completed, the component will be transported to the ITER construction site and is expected to leave Mangiarotti later this year by boat for the port of Marseille. From there, it will be loaded onto a large track, and by applying the protocol of a heavy exceptional convoy, it will be transported to the site.
Construction of ITER is funded mainly by the European Union (45.6%) with the remainder shared equally by China, India, Japan, Korea, Russia and the USA (9.1% each). However, in practice, the members deliver little monetary contribution to the project, instead providing ‘in-kind’ contributions of components, systems or buildings.
Image: ITER's vacuum vessel sector No. 5 (courtesy of F4E)