Europe hands over the first power supply unit to heat ITER

The first set of European power supplies is ready to light up ITER’s gyrotrons. Fusion for Energy (F4E) is responsible for providing eight units and has been working since 2013 with the Swiss SME Ampegon to deliver them. After series production and installation onsite, the teams energised the system for the first time last year, paving the way for commissioning. One unit has now completed the full sequence of tests, so F4E handed it to ITER Organization, that will operate it as part of the Electron Cyclotron Heating system.

Let’s take a closer look at this technology. The power supplies are designed to convert electricity from ITER’s grid into regulated high voltage and current for the gyrotrons. These devices will generate high-power microwaves, which are then launched into the reactor to heat and stabilise the plasma.

Each of the eight units consists of a Main High Voltage Power Supply (MHVPS) and two body power supplies (BPS), and can feed two gyrotrons. One MHVPS can deliver up to 6MW of energy (at 55kV of Direct Voltage and 110A), that is, enough electricity for the households of a small city.

Besides their nominal capacity, the power supplies are also highly responsive. They can quickly adjust the voltage to different heating scenarios and switch off in microseconds. Operators will run these commands digitally, through the ITER CODAC, the central control architecture of the experiment.

F4E, Ampegon and ITER Organization devised a thorough commissioning plan to verify that the units can meet the demanding performance and safety requirements. During the last months, technicians from the supplier worked daily in the ITER Radiofrequency Building, where the equipment is installed. They gradually powered up the MHVPS and BPS and checked a wide range of aspects, such as the speed to reach maximum voltage or the response of the switchgears. First, they operated the system via the local control unit, then remotely through CODAC.

Cyril Lescure, F4E Technical Officer, followed the process closely: “Commissioning the first unit is the steep part of the learning curve. The plans devised on paper are applied in practice, and new issues often arise. Now, this experience will help us streamline and derisk the process for the next units,” he explains.

“Commissioning puts both the equipment and our expertise as a team to the test. The project is advancing thanks to the effective collaboration among Ampegon, F4E and ITER Organization. We will continue working to demonstrate efficiently and robustly that the equipment can perform as expected,” adds Marcel Frei, Head of R&D at Ampegon.

“The results of the site acceptance tests are very promising. So far, they’ve confirmed the system’s excellent output voltage stability and dynamic response, with very low energy dissipation. All these factors will contribute to the improved performance and reliability of the overall Electron Cyclotron Heating,” claims Ferran Albajar, F4E Programme Manager.

The European unit, now in the hands of ITER Organization, won’t be idle for long. A new campaign of tests started this week, which should culminate in the integration of a Japanese gyrotron with Europe’s power supply. This will mark the first time one of ITER’s heating systems is lit up on site — an electrifying milestone for the project and the international partners involved.