The International Thermonuclear Experimental Reactor (ITER) project has reached a significant milestone with the successful evaluation of the vacuum vessel (VV), a key component of the tokamak fusion reactor. This evaluation was detailed in a recent article published in the journal Nuclear Fusion, led by Hokyu Moon from the ITER Tokamak Engineering Department at the Korea Institute of Fusion Energy.
The ITER vacuum vessel is designed to contain the plasma and maintain the necessary conditions for nuclear fusion. The first sector of this vessel was delivered to the ITER Organization in 2020 and is now ready for assembly. As part of ensuring its functionality, a comprehensive factory acceptance test (FAT) was conducted to confirm the vessel’s performance against essential criteria such as vacuum leak tightness and structural integrity.
The FAT process included several critical assessments. Visual inspections confirmed that there were no blockages in the cooling channels, which are vital for regulating temperature within the reactor. A pre-pumping assessment verified that the vacuum level and residual gas conditions inside the vessel were flawless, meeting the stringent leak test requirement of 1 × 10^−8 Pa m^3 s^−1. Furthermore, both the pressure test and helium leak test demonstrated that the vacuum vessel maintained exceptional leak tightness, with results indicating a leak rate of 6.08 × 10^−9 Pa m^3 s^−1, surpassing the allowable limits.
Despite encountering some unavoidable weld deformation, the three-dimensional metrology used to assess the vessel’s dimensions provided valuable data for future assembly with other components. Moon noted, “The as-built result does not perfectly meet the assigned tolerance level. Nevertheless, it can be considered as advanced information for assembly.” This insight will be crucial as additional sectors of the vacuum vessel are manufactured and delivered, particularly as Korea is set to play a significant role in the ongoing development of the ITER project.
The successful evaluation of the ITER vacuum vessel not only marks a crucial step in the advancement of fusion energy but also opens up commercial opportunities across various sectors. Companies involved in manufacturing, engineering, and technology development can benefit from the insights gained during this testing phase. As the demand for clean and sustainable energy sources continues to rise, the ITER project stands at the forefront of fusion research, promising potential breakthroughs that could reshape the energy landscape.
The findings from this evaluation, as presented by Hokyu Moon and his team, highlight the rigorous standards required for components in fusion reactors. As the ITER project progresses, the collaboration between international partners and the sharing of technological advancements will be vital in realizing the goal of practical fusion energy, paving the way for future energy solutions.
