MITICA Cryopump in production

SDMS operator preparing the set up for the automatic welding of a pumping section. Behind him, a vacuum testing chamber for pressure, leak and thermal shock tests. In the background, multiple pumping sections (inside plastic bags) hooked from the storage frame. SDMS, France, February 2022. © SDMS

The plasma contained in the ITER Vacuum Vessel will reach 150 million °C, ten times the temperature at the core of the Sun. The neutral beam system, one of the heating systems of the device, will launch extremely energetic particles into the vacuum vessel to help us reach these extremely high values for the fusion reactions to occur. To ensure that we become more familiar with the technology required for such a system, Consorzio RFX is hosting in Padua (Italy) a neutral beam prototype system called MITICA.

One of the main components of MITICA is the cryopump, which will provide the vacuum conditions needed for the experiment. Broadly speaking, the cryopump is composed of two pumping assemblies, each of them consisting of a frame with 32 pumping sections. These and other subsystems passed what engineers call a manufacturing readiness review (MRR) making sure that everything is in place for the production phase, and half of the pumping sections have already been manufactured. They expect to finish their production towards the end of summer.

With respect to the frames, the parts of the first one have been produced and experts will finish its assembly by mid-March. Other subsystems of the pumping assemblies, such as the temperature sensor, will have their own qualification process in the following weeks. Daniel Dupuy, Technical Project Officer in charge of this contract, gives more details. “Despite the challenges encountered at the beginning, the production of this equipment and the assembly of the frame is progressing well on track thanks to the good collaboration with our stakeholders (ITER Organization, RFX and SDMS).”

Manual welding of a pumping section for the testing configuration prior to its introduction in the vacuum testing chamber. SDMS, France, February 2022. © SDMS

With frame, pumping sections and the other components ready, the assembly of the cryopump will follow, which will be done with a transportation-assembly tool specifically prepared for this. The tool will also be used to send the cryopump from the SDMS premises in Saint-Romans (France) to Padua. The Factory Acceptance Test is expected towards the end of the year.

Readjustment of some subcomponents of a pumping section after its welding. SDMS, France, February 2022. © SDMS

Josep Benet, F4E, took over as Project Manager in charge of these activities in mid-2021. “Thanks to the effort done by all parties and the manufacturing knowledge and expertise provided by SDMS, the result of the work performed during last years can be found in the workshop. I am glad to see a committed team that works to deliver this high-quality cryogenic equipment.” From all these activities we will be able to draw lessons for the neutral beam injector cryopumps that will operate in ITER. ITER Organization is already preparing the specifications of these cryopumps, which F4E will have to deliver. Engineers expect to have their final design towards the end of the year.

Partially assembled MITICA Cryopump frame, just missing 2 m of the total 8 m in length. SDMS, France, February 2022. © F4E