ITER Duct Liner Manufacturing Readiness Review Approval

Recently, the consortium led by the Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences (ASIPP), with members including DWELL COMPANY LIMITED (DWELL), Hefei Juneng Electro Physics High-tech Development Co., Ltd. (JUNENG), and Beijing Zhong Hang Ke Dian Measurement & Control Co., Ltd. (ZHKD), has passed the Manufacturing Readiness Review (MRR) for the ITER Duct Liner (DL).

The ITER DL comprises three complete assemblies in total, each consisting of a Neutron Shield (NS), Duct Liner modules (DLMs), a Neutron Shield extension (NSE), and main water cooling pipes. As a high heat flux protection component at the ITER Vacuum Vessel Duct, the DL has four critical functions: interception of neutral beam edge particles, radiation protection of the vacuum vessel, neutron shielding, and active cooling to handle high heat loads. The Neutron Shield, with dimensions of 4950 mm (length)×1949 mm (height)×1122 mm (width), is built from welded plates with thicknesses mostly ranging from 25 to 50 mm, making the construction complex. Manufacturing faces multiple challenges, including precision machining of the long inner wall, high-precision deep hole machining, and welding of dissimilar materials. In response to the above manufacturing difficulties, the consortium evaluated and validated the manufacturing processes, designed a special machine tool for inner wall machining to fully meet the precision requirements, adopted a stepped drilling process to precisely control hole deviation and achieve the specified drawing accuracy, and established electron beam and laser welding platforms to resolve dissimilar material welding issues.

The review panel also highly commended our prototype for dissimilar material welding, which demonstrates solid engineering capability. With the MRR approval, the preparatory work for the ITER DL has been successfully completed, and the consortium is now cleared to start manufacturing the prototypes. This milestone also provides a solid technical foundation for the subsequent development of both prototypes and production units.

Figure 1. Cooling Water Coaxial (CWC) prototype (Include 316L, inconel 718 and 625).

Figure 2. MRR On‑site Photo.