The ITER Cryopumps will ensure the proper vacuum conditions in the device. Six of them will pump out the residual gas from the vacuum vessel housing the fusion reaction, while another two will deal with the cryostat, providing the appropriate environment to the vacuum vessel and superconducting magnets inside. The manufacturing of these pieces of equipment started recently, and the first parts of the equipment are ready!
They will perform the pumping: supercold (-269°C) rectangular-shaped cryopanels measuring 1 m long and 0.2 m wide will trap the gas particles. In addition, several kinds of thermal radiation shields are also in production. They will function at about -193°C to prevent the cryopanels from heating. All the components are stainless steel and liquid helium will circulate through them to keep them cool.
F4E has entrusted Research Instruments (RI) and ALSYOM with the manufacturing of the cryopumps. Leering is a subcontractor that has joined forces with RI to fabricate these first components. These pieces of equipment have one thing in common: they are hydroformed. The basic idea of this process is to laser weld two stainless steel plates following certain patterns. Then, introducing pressurised gas between the plates, the non-welded areas “inflate” like a balloon, reaching the desired shape. “The cold surface area that is needed to achieve the required pumping efficiencies in the ITER machine finds with the hydroformed components the optimum manufacturing technology available in industry,” explains Matthias Dremel, ITER Organization Procurement Arrangement Responsible.
These components will be handling the gases from the fusion reaction during the entire lifetime of ITER. Luis Mora, F4E Technical Responsible, adds that “…the panels, after being hydroformed, will go through different processes which are essential for their operation. These components are the heart of the cryopumps. Once installed inside them, they will remain there, without any access to them unless the cryopumps are completely disassembled.”