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Vessel for artificial sun, the first sector of ITER vacuum vessel completed


Date of registration 2020-09-24



Vessel to contain artificial sun of one hundred million degree Celsius Plasma - First sector of ITER vacuum vessel completed

Vacuum Vessel

The first segment (sector #6) of the ‘vacuum vessel’, a key component for the International Thermonuclear Experimental Reactor (ITER) project has been completed in South Korea and has arrived in France, the construction site of the ITER. 

NFRI held a ceremony to celebrate the successful manufacture of the first ITER vacuum vessel sector at Hyundai Heavy Industries Co., Ltd. (HHI) in Ulsan on April 20, 2020 (Monday) with about 30 people from the government, research institutes, and industries in attendance considering COVID-19 situation.

The ITER construction will enter the stage of assembly and installation beyond stage of manufacturing & construction up to now. NFRI and HHI. have overcome numerous technical challenges for the past ten years and successfully completed the first sector of the vacuum vessel under the support of ITER organization. 

The ITER vacuum vessel, which is made up of nine sectors, is a doughnut-shaped heavy mechanical structure which will measure 13.8 meters in height, 19.4 meters in outer diameter, and total weigh about 5,000 tons after assembly. The sector #6 (11.3 meters in height, 6.6 meters in width, and weight 400 tons), the first-completed sector #6 is the reference point for assembly and installation of the vacuum vessel system. Only when it is successfully installed, other sectors can be assembled and installed sequentially. Now that the sector #6, which will be first fabricated among nine sectors of the ITER vacuum vessel, is faced with difficulties that it has to first resolve various technical challenges as a First-of-a-Kind(FOAK). 

The vacuum vessel located at the innermost part of the nuclear fusion reactor serves as a vessel that creates a high vacuum environment so that it can generate and maintain an ultra-high temperature plasma of more than 100 million degree Celsius in which nuclear fusion reaction occurs. In addition, it acts as a primary confinement barrier that shields neutrons generated during nuclear fusion processes and a platform that precisely fixes in-vessel components of the nuclear fusion reactor such as the blanket and the divertor. 

In particular, the vacuum vessel, which is a 3D-shaped, double wall structure, made of a special stainless steel, requires addressing the most difficult technical challenges and complying with rigorous quality control in the manufacturing process in order to provide a perfect vacuum condition. It also needs precious fabrication and welding technology, including following tolerances of several millimeters or below for the purpose of the precious assembly of numerous in-vessel components during the welding process for total 1-kilometer-special stainless steel with a thicknesses of 60mm. In addition, in order to comply with the French nuclear safety regulations, which requires a 100% precise non-destructive testing, a new non-destructive testing technology that can completely inspect major welded parts has been developed and applied.

“We are really happy to overcome many technical limitations and successfully complete the sector #6 of the vacuum vessel in ten years,” said Han Young-seuk, President and CEO of HHI which is responsible for manufacturing the vacuum vessel. “Based on our experience in completing the first sector, we will make every effort to procure the remaining three sectors in a timely manner to contribute to the successful construction of ITER.”

Currently, HHI is in charge of four of the ITER’s nine vacuum vessel sectors. The remainder has been built in the European Union (EU). After winning an order to supply two vacuum vessel sectors, HHI won an additional contract to supply two sectors from the EU.

Bernard BIGOT, Director-General of ITER Organization, who was not able to visit South Korea due to the spread of COVID-19, said in a video, “The successful completion of the vacuum vessel sector #6 despite numerous challenges is a real victory achieved through the cooperation between South Korea and the global vacuum vessel team and I am grateful for the strong support from the South Korean government, as well as the country’s academy-industry cooperation which have played a crucial role in pursuing the ITER project.”

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