To master the technologies of a Neutral Beam Injector (NBI), the powerful heating system that will help us raise the temperature of the ITER plasma up to 150 million °C, a test facility has been set up in Padua (Italy). Its name is MITICA and it promises to bring the myth of fusion energy a step closer to reality.
Engineers from F4E in partnership with companies, ITER Organization (IO), India, Japan and Consorzio RFX, are going through the manufacturing learning curve to deliver the equipment of the NBI prototype. Subsequently, they will spend time operating it in order to identify any technical issues and improvements before the production of the “real” equipment begins. The NBI will be able to deliver up to 1 MeV – an unprecedented amount of energy, the same of the injectors that will be used in ITER.
Several components of the MITICA experiment have already been completed and handed over to IO. The MITCA Vacuum Vessel, procured by F4E, is the latest European component to follow suit. De Pretto industrie was entrusted with its fabrication. The vessel consists of two parts weighing in total 127 t (60 t + 67 t). Their final welding operations started at the ITER Neutral Beam Test Facility (NBTF) early in May as soon as the COVID-19 restrictions were lifted by the Italian government. They were successfully completed in spite of the severe difficulties experienced at that time. The technicians had to install scaffolding outside and inside the vessel in order to connect the two parts of the vessel, welding in all positions (360 °). A total of 12 m of welding was carried out in one week.
The first part of the vacuum vessel was delivered last year, while the second one a few months ago. More than 300 manufacturing drawings were developed for the fabrication of the component. The vessel counts at least 1km of welds performed mainly by TIG (Tungsten Inert Gas) technique. Its surfaces were chemically cleaned to comply with the needs of the ultra-high vacuum conditions for testing and operation. Many important technical aspects had to be taken into account to connect hydraulic lines, cooling pipes, gas and vacuum system, cryopumps and viewports reaching a total of 119. Specific features had to be considered to match with other in-vessel pieces of equipment such as the beam source, beam line components and the cryogenic pumps that will be installed inside the vessel.
Gonzalo Micó, F4E Project Manager responsible for this contract, highlights the significance of this achievement. “The vacuum vessel of the most powerful neutral beam injector is ready to be handed over. It’s the culmination of some years of hard work, lengthy exchanges, and strict factory and site acceptance tests. The good collaboration with De Pretto Industrie, ITER Organization and RFX was instrumental. We are now working full speed to produce the components that will be installed inside,” he explains.
Tullio Bonicelli, F4E Programme Manager for Neutral Beam & Electron Cyclotron Power Supplies and Sources, has seen the evolution of the ITER NBTF from the beginning. “We started by honouring our contribution to SPIDER – the first experiment of the ITER NBTF which is in operation – and we are continuing by delivering at a steady pace our share of equipment to MITICA. The completion of the vacuum vessel together with the excellent results of the power supply systems in place, will allow important experiments on 1 MeV in vacuum to be performed, which is one of the critical aspects of the ITER injectors. This delivery demonstrates that Europe is and will continue to be a strategic partner in developing key systems for fusion technologies.”
We also touched base with the F4E industrial partners to find out what this achievement meant to them. For Diego Ruaro, De Pretto Industrie Sales Manager, the handover of the MITICA Vacuum Vessels has marked a milestone both for the company and the project. “De Pretto Industrie is proud of its valuable contribution to the future of fusion energy in the frame of the ITER project. From the start of the contract, De Pretto Industrie has been committed to analysing and solving all engineering and manufacturing challenges of the NBI vessels, in order to achieve the technical results with the upmost quality,” he explains. Mauro Giupponi, De Pretto Industrie Project Manager, underlines that “in spite of the current restrictions of COVID-19, affecting the last stages of the contract, we were able to manage the on-site installation and testing activities in safe and clean conditions, thanks to the full support of Fusion for Energy, Consorzio RFX and ITER Organization.”