MITICA testbed: final installation scheduled to begin
At the ITER Neutral Beam Test Facility in Padua, Italy, engineers have just taken delivery of the last two major components of MITICA—the full-scale prototype of ITER’s heating neutral beam injectors. The team is turning its attention to final assembly and commissioning.
MITICA is one of two test beds at the Neutral Beam Test Facility established to develop and validate the technology for ITER’s powerful neutral beam injection system. On ITER, two heating neutral beam injectors will each deliver up to 16.5 MW of heating power to the plasma by accelerating negatively charged ions to an energy of 1 MeV, neutralizing them, and injecting the resulting high-energy particles into the plasma.
SPIDER has been in operation since 2018 and is dedicated specifically to the production and extraction of negative ions. MITICA takes the development program a significant step further by reproducing the complete injector at full scale and full voltage.
Inside the MITICA beam source, four pairs of radiofrequency drivers turn hydrogen or deuterium gas into a plasma. A specially treated grid extracts negatively charged ions out of the plasma, while a multistage accelerator accelerates them up to voltages approaching 1 million volts. The result is a beam of particles carrying up to 40 megawatts (MW) of power, making MITICA the most powerful ion source ever built.
Its arrival in June 2026 at the Neutral Beam Test Facility was the culmination of a European procurement effort led by the European Domestic Agency Fusion for Energy (F4E), involving Research Instruments GmbH, Galvano-T, CECOM and 3DMF, with final assembly and testing performed by ALSYMEX in collaboration with F4E.
At the opposite end of the MITICA beamline, the calorimeter will provide an essential diagnostic function during testing. Delivered by F4E and manufactured by the AVS-Tecnalia consortium, it is designed to intercept the full-power particle beam during commissioning and conditioning operations, allowing engineers to characterize its profile and intensity (reaching up to 14 MW/m²).
With the site acceptance testing of both components completed, final installation is scheduled to begin in spring 2027. In the meantime, work is progressing on another critical part of the test bed: the high-voltage power supply system. A fault in the 1 MV insulation transformer initially threatened to impact the program. Parallelizing activities and reorganizing the schedule has reduced the expected delay from approximately ten months to five.
Repairs are now nearing completion, while testing of cryogenic cooling panels is also underway. The next major electrical milestone will be to bring the acceleration grid power supplies to their full 1 MV rating against a dummy load, demonstrating that the system is ready for the demanding conditions of beam operation.
Commissioning of MITICA is planned to begin in summer 2027, opening a new phase at the ITER Neutral Beam Test Facility as the technologies destined for ITER’s two heating neutral beam injectors are tested and qualified at full scale.