HD Hyundai Heavy Industries finished assembling its fourth and final ITER vacuum vessel sector on July 22, 2026, clearing the way for the reactor's donut-shaped vessel to come together at the ITER construction site in Cadarache, southern France.
The Korean shipbuilder marked the milestone at "KOREA-ITER Fusion Day," an event at the Cadarache site that drew about 150 people, including representatives from South Korea's Ministry of Science and ICT, domestic companies, research institutes and the ITER Organization. The gathering celebrated the finished sector, now combined with thermal shields and superconducting magnets into a complete sector module. That module has moved to the Tokamak pit, where it will join eight others to form a vacuum vessel weighing about 5,000 tons.
Four of nine sectors
ITER, the International Thermonuclear Experimental Reactor, is a joint project of seven members: South Korea, the European Union, the United States, Japan, China, Russia and India. HD Hyundai built four of the nine vacuum vessel sectors that make up the reactor. The company won the contract for two sectors allocated to South Korea in 2010, added an order for two more sectors originally assigned to the EU in 2016, and delivered all four by 2024.
Each sector stands 11.3 meters tall, spans 6.6 meters wide and weighs about 400 tons. The vacuum vessel has to hold plasma hotter than 100 million degrees Celsius while keeping an ultra-high vacuum around it, so the sectors had to meet French nuclear pressure equipment rules along with international nuclear engineering and ITER Organization standards. HD Hyundai said it built the sectors on manufacturing know-how from its shipbuilding and offshore plant business. The company received a plaque of appreciation at the event.
A longer fusion track record
Won Kwang-shik, HD Hyundai's senior executive vice president, spoke at the event on behalf of the participating companies, calling the finished sectors "a major milestone that demonstrates both the technological competitiveness of Korean industry." He said the company would keep applying that experience toward future power generation.
HD Hyundai's fusion work predates ITER. The company took part in the main structure design of KSTAR, South Korea's own Superconducting Tokamak Advanced Research reactor completed in 2007, and built its core components, including a large ultra-high vacuum vessel and cryostat.
In a tokamak, the donut-shaped structure at the center of a fusion reactor, superconducting magnets generate the magnetic field that confines the plasma, while a thermal shield keeps heat from the vacuum vessel from reaching those magnets, which run at cryogenic temperatures.
