Europe delivers final ITER vacuum vessel sector

The International Thermonuclear Experimental Reactor's (ITER's) plasma chamber, or vacuum vessel, houses the fusion reactions and acts as a first safety containment barrier. With an interior volume of 1,400 cubic metres, it will be formed from nine wedge-shaped steel sectors that measure more than 14 metres in height and weigh 440 tonnes. 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. With the subsequent installation of in-vessel components such as the blanket and the divertor, the vacuum vessel will weigh 8,500 tonnes.

Each vacuum vessel sector is manufactured in four segments, requiring more than 1.6 kilometres of welding for assembly. Maintaining precise tolerances of less than a few millimetres ensures the seamless integration of internal components, which demands advanced forming and welding technologies.

The fabrication of the vacuum vessel sectors is shared between Europe (five sectors) and South Korea (four sectors). Initially, South Korea was tasked with producing two vacuum vessel sectors under its agreement with the ITER Organisation. However, in 2016, an additional agreement was made to produce two more sectors originally assigned to the EU.

_{Final work on the sector at Westinghouse's workshop in Monfalcone (Image: F4E)}

Starting with the delivery of the first sector in 2020 and the final one in November 2024, South Korea completed four sectors, fulfilling its commitment to this significant international project.

Europe has now delivered its fifth and final sector. The component left the factory of Westinghouse in Monfalcone, Italy, and was safely transported by DAHER to the ITER site in Cadarache. The arrival of the sector marks the end of a manufacturing journey that started 16 years ago and is officially the last large ITER component delivered on-site.

It took more than 2 million hours to produce Europe's five sectors, counting in total 750 km of welding beads, Fusion for Energy (F4E), the ITER Organisation's European domestic agency, said. The production of segments, the four parts that make a sector, was carried out in Westinghouse, Monfalcone, and in Walter Tosto, Chieti. Once the segments were assembled, they were welded to become one sector. Then, the component was transported by sea and land to reach the ITER site.

"Thanks to the optimal use of resources, rigorous project planning and the application of good manufacturing practice, Europe delivered all of its five sectors in the last two years," F4E said. "F4E innovated by using AI in order to cross-check data collected by technical teams in the factories."

_{The component is unloaded at the port of Fos-sur-Mer, in France (Image: DAHER)}

F4E Director Marc Lachaise said: "Europe's final sector results from the strong partnership between F4E, the consortium of Ansaldo Nucleare, Westinghouse, and Walter Tosto. We worked as one team, in an integrated manner with ITER Organisation, and built on the lessons learned from ITER Korea in producing the rest of the sectors. Our commitment to deliver and the resilience of our teams have brought us to the finish line. It's a high-tech component made in Europe, by European companies, at a time when knowledge and expertise matter in the fusion race. Thanks to the EU's involvement in ITER, F4E, together with the companies, is shaping the potential of fusion energy."

The ITER project
 
ITER is a major international project to build a tokamak fusion device designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy. The goal of ITER is to operate at 500 MW (for at least 400 seconds continuously) with 50 MW of plasma heating power input. It appears that an additional 300 MWe of electricity input may be required in operation. No electricity will be generated at ITER.

Thirty-five nations are collaborating to build ITER - the European Union is contributing almost half of the cost of its construction, while the other six members (China, India, Japan, South Korea, Russia and the USA) are contributing equally to the rest. Construction began in 2010 and the original 2018 first plasma target date was put back to 2025 by the ITER council in 2016. However, in June last year, a revamped project plan was announced which aims for "a scientifically and technically robust initial phase of operations, including deuterium-deuterium fusion operation in 2035 followed by full magnetic energy and plasma current operation".