Recently, the team from the Southwestern Institute of Physics under the China National Nuclear Corporation (CNNC) has made significant progress in the field of wall treatment technology for the International Thermonuclear Experimental Reactor (ITER): not only did it successfully pass the Delta Final Design Review (Delta FDR) for the supplementary design of the Glow Discharge Cleaning (GDC) system permanent electrode project, but it also led and jointly with China Nuclear Industry 23 Construction Co., Ltd. (CNI23) won the bid and signed contracts in France for the design and manufacturing of the Boronization System and the X-Ray Crystal Spectrometer (XRCS) Gas Supply System. This marks an expansion of the Chinese team's achievements in the core technology of ITER device wall treatment, extending its business scope from the original glow discharge cleaning to boronization wall treatment, achieving a full technical chain from impurity removal to surface pre-treatment, which will provide critical support for the operation of ITER's full-tungsten first wall.

These two tasks are directly related to ITER's strategic design change in 2023 to replace the first wall material from beryllium to tungsten. Although tungsten is resistant to high temperatures, the impurities it releases can severely contaminate the plasma, especially during the sensitive discharge start-up phase, where even trace amounts of impurities can lead to uncontrolled energy radiation losses. Acting as a "powerful vacuum cleaner" inside the ITER vacuum vessel, the GDC system, for which the Chinese team is responsible, generates cold plasma through glow discharge to bombard and remove residual gases and impurities adsorbed on the vessel walls. This Delta FDR special review overcame the manufacturing feasibility challenges of the electrodes in complex spatial configurations, clearing the final obstacle for the entire GDC system to transition from design drawings to engineering manufacturing.

Meanwhile, the newly awarded Boronization System plays the role of a precision "surface coating specialist." To address the impurity risks posed by the full-tungsten wall, this system uses glow discharge-assisted deposition to coat all plasma-facing surfaces with a boron film only 10-100 nanometers thick. This low-atomic-number boron film acts as a physical barrier, effectively suppressing the sputtering release of high-atomic-number tungsten impurities, while also functioning like a sponge to efficiently capture and "absorb" impurities such as oxygen and carbon escaping from the vessel walls, preventing them from entering the plasma core and causing radiation cooling. It is worth noting that the design of this boronization system will incorporate test experience from multiple existing tokamaks, marking its first application in a large-scale ITER device, and it will be compatible with future tritium-containing operating environments, providing support for ITER experimental operations.

According to the contract agreements, the consortium will undertake the full-cycle tasks from detailed design, equipment manufacturing, to on-site installation, fully demonstrating the comprehensive capabilities of the Chinese team in the integration of complex fusion engineering systems.

During exchanges with the Chinese team, Luolong, Deputy Director-General of the ITER Organization, highly commended the coordinated advancement of the GDC and Boronization projects. As the next step, the Chinese team will strictly follow the ITER overall plan, deliver high-quality GDC electrode manufacturing and meet the milestones of the new contracts, and continue to contribute Chinese wisdom and strength to the international development of fusion energy with solid technical expertise and outstanding engineering practice.