The project to build a cold test facility for the ITER magnets is bringing together experts from across ITER, as they race to seize a golden opportunity to test magnets and associated systems at 4 K (minus 269 °C). As development of the 2024 ITER baseline was underway, it became apparent that the revised schedule for machine assembly would allow for time to conduct valuable cold testing on some of the tokamak’s D-shaped toroidal field coils, as well as the smallest poloidal field coil (PF1) and other key systems required for magnet operation. But there was one catch: the window of opportunity was so small that the testing project would have to advance at double speed.'To achieve this goal, the magnet cold test facility project was launched in June 2023 and a matrixed team from different units of ITER was quickly established to fast-track design, procurement, manufacturing, and installation. Now, major design and procurement milestones are being reached for this project-within-a-project and the facility is on pace for initial commissioning to begin this summer, leading to the installation receiving its first magnet for 4 K testing by the end of the year. A coil terminal box is one of the elements of a magnet feeder—complex components that distribute and recover cryogenic fluids at different temperatures and connect the magnets to their power supplies. The operation of this unit, moved into place in the magnet cold test facility in March, will provide valuable feedback to ITER generally on its operation at 4 K. “In a little more than a year and a half—less than half the ‘normal time’ an operation like this would usually take—we’ve gone from nothing to a design that is essentially finalized, equipment either delivered or in manufacturing, and installation works underway,” says Karim El Hamdani, the project leader for the test facility. “We’re meeting these challenges because everybody was very agile at ITER, and we were able to set up a multidisciplinary team including magnet, cryogenics, electrical, instrumentation, control, vacuum, building, and procurement specialists. Because this was a priority, everyone had a clear goal with very, very tight deadlines.”Located in the former Poloidal Field Coils Winding Facility, the cold test facility will have its own cryostat and power system to cool magnets to 4 K (minus 269 °C) and energize them up to 68 kA—offering a real-scale test of a diverse set of toroidal field coils, from multiple coil and conductor manufacturers, as well as a general rehearsal for auxiliary systems (feeders, cryogenics, control-command…) to derisk that portion of integrated commissioning. A close-up view of how a D-shaped magnet will be prepared for testing in the cryostat of the magnet cold test facility. Testing at 4 K will also verify the operation of associated infrastructure such as instrumentation. In 2024, test facility design was finalized in collaboration with a panel of international experts. With most of the components now completed and at ITER, the facility is moving rapidly to the commissioning phase thanks to progress being made on parallel fronts:Cryostat – A 330-tonne customized cryostat (10.5 m x 21.2 m x 6 m) is in fabrication and the overall manufacturing progress is near 75%.Power supply system – A customized 68 kA power supply system is in fabrication and overall manufacturing progress is near 95%. Final factory acceptance tests are proceeding.Cryogenics, vacuum system – The valve box, the cryo and auxiliary lines, and the required vacuum pumps, valves, and baffles are nearing manufacturing completion, while simulations have been run for the cool-down and warm-up of toroidal field magnets.Building – Some requalification activities are underway to adapt the former winding facility to the needs of the test facility: for example, the gantry crane must be adapted to lift toroidal field coils (testing is planned in May with a first toroidal field coil trial lift).Feeder – In another sub-project, feeder components that will eventually be used in the tokamak have been delivered for testing. Because the toroidal coils will be tested horizontally instead of in their ultimate vertical position, a customized interface, the in-cryostat feeder, is being manufactured, with delivery expected in late June.Instrumentation – Software for quench detection is practically completed and manufacturing is underway or finalized for high- and low-voltage cables and devices.Control – Design of the central control system is almost completed, software development is in progress, and the control cabinets are being manufactured.Facility scope – The matrixed team that completed the assessment of facility requirements/design, supporting analysis (structural, thermohydraulic, magnet protection), and test plans will also be mobilized during facility commissioning and operation. Experts from the European Domestic Agency Fusion for Energy joined for the design and procurement phase to accelerate the process.  A matrixed team of about three dozen people from different units at ITER has worked to fast-track the magnet cold test facility, going from "nothing" to "installation works underway" in roughly half the normal time an operation like this would normally take. The team includes magnet, cryogenics, electrical, instrumentation, control, vacuum, building, and procurement specialists around Karim El Hamdani, project leader (centre, light-coloured jeans), and magnet project engineer Thierry Schild (behind Karim, immediately to the right). “This project has already achieved success as it has brought all the specialists required to operate the magnet system together to achieve a challenging and motivating short-term goal,” says Thierry Schild, who is overseeing the technical aspects of the test facility. “We’ve already identified many interfacing and operating questions to be answered during facility operation, which will be very precious know-how for machine commissioning.”While the installation activities are ramping up, the magnet cold test facility will be connected to the cryoplant before the summer and commissioning tests without the cryostat are scheduled to begin in July. Once the cryostat arrives in September and is installed, preparations will begin for the testing of the first toroidal field coil. The facility is expected to operate for several years, with approximately four to six months required per magnet. 

A sixth central solenoid module has successfully completed testing at the General Atomics Magnet Technologies Center in Poway, California. US ITER and supplier General Atomics have finished testing the sixth and final module required for the 18-metre-tall superconducting magnet at the heart of ITER. Only a seventh module, to be used as a spare, remains to be finalized.Each 4-metre-wide, 110-tonne cylindrical module is wound from niobium-tin superconducting cable produced in Japan and requires more than two years of precision fabrication and verification. The final phase, in-factory testing, verifies performance by simulating conditions that the module will experience during operation at ITER.The sixth production module, which is the last module required to complete the central solenoid stack, was subjected to a series of demanding tests including helium leak testing, high voltage insulation testing, cooldown to 4.5 K and charging to 48.5 kA followed by a series of tests designed to measure as-built performance of the superconductor.Four central solenoid modules have already been delivered by US ITER and stacked on a dedicated assembly platform. The fifth module is en route and the sixth will ship in summer. US ITER has also delivered the “exoskeleton” support structure that will enable the central solenoid to withstand the extreme forces it will generate. The exoskeleton is comprised of more than 9,000 individual parts, manufactured by eight US suppliers.

The recent “high-voltage holding in vacuum” tests on MITICA—the full-size prototype of ITER’s heating neutral beam injector—mark a crucial step in advancing ITER's neutral beam heating system.  The recent test campaign on MITICA successfully demonstrated the system’s ability to maintain high voltage in a vacuum environment, reaching the expected voltage-holding capabilities. Due to the unavailability of the final power supply system—set to arrive at the ITER Neutral Beam Test Facility in Padau, Italy, in the coming weeks—a provisional testing generator was used, capable of optimizing the voltage rise on three out of five acceleration stages. The best value obtained, 430 kV in high vacuum on three stages, corresponds to 710 kV on the full set of five stages, surpassing the target of 700 kV established in the ITER research plan for the end of MITICA’s first campaign, planned in 2027.Moreover, to investigate all relevant operating conditions, hydrogen gas was injected into the vessel, scanning pressure values between 30 and 50 mPa—typical for MITICA (and ITER heating neutral beam) operation. Under these conditions, the system maintained a maximum voltage of 546 kV on three stages, corresponding to a projected 910 kV across the full configuration. This exceeds the maximum operation voltage required in hydrogen at full performance (870 kV).Both results reported were also confirmed with additional pulses where the voltage holding was kept successfully for more than an hour—the maximum pulse length foreseen in ITER operation. A visualization of the MITICA testbed, where ITER's full-size 1 MV heating neutral beam injector technology will be tested in advance of operation. Source: Consorzio RFX It should be noted that these tests were carried out without the MITICA beam source, which is scheduled for delivery this autumn. Instead, an electrostatic full-scale mock-up, designed to replicate the beam source’s electrostatic behaviour, was used. Supplied by Italian manufacturer Fantini Sud SpA, this mock-up was installed inside the MITICA vacuum vessel to study the high-voltage behaviour of the test bed and identify potential issues and challenges before integrating the complete injector system. In particular, it allowed for the testing of an electrostatic shield—connected to the 600 kV acceleration stage and designed to match the 600 kV equipotential surface—which provided the improved voltage holding compared to the previous, unshielded design.The success of these tests confirms MITICA’s readiness for further testing and integration. Once fully operational, its beam source will generate and accelerate negative ions, which will then be neutralized, as required for neutral beam injection into the ITER tokamak. Already operating in Padua is the SPIDER testbed, an ITER-scale negative ion source designed to achieve all ion source requirements.The Neutral Beam Test Facility is the result of a collaboration between the ITER Organization and Consorzio RFX, with the contribution of EUROfusion and in cooperation with the European, Japanese and Indian ITER Domestic Agencies. For more information, see this ITER webpage.

At the heart of fusion energy lies one of the universe’s most untamed elements: plasma—a high-energy state of matter seen in lightning, the aurora, and most spectacularly, in our sun. Scientists have spent decades trying to control it. But why? In this episode, host Kruti Fayot dives into the fascinating world of plasma: what it is, why it’s essential for fusion, how it’s being tamed inside machines like ITER, and the surprising role AI might play in the future of clean energy. Featuring insights from ITER experts Javier Artola, Michael Walsh, and Alberto Loarte, with a special introduction by plasma physicist Melanie Windridge and fusion analyst Jack Moore. If you’ve ever looked up at the Northern Lights or wondered how we’ll power the future — this one's for you.Episode 3 of Behind the Science of Fusion is available now.Find it on the ITER website's podcast page or open it directly here. You can also find the ITER podcast at Spotify, Amazon Music, Apple Podcasts, and Podbean.