Subscribe options

Select your newsletters:

Please enter your email address:

@

Your email address will only be used for the purpose of sending you the ITER Organization publication(s) that you have requested. ITER Organization will not transfer your email address or other personal data to any other party or use it for commercial purposes.

If you change your mind, you can easily unsubscribe by clicking the unsubscribe option at the bottom of an email you've received from ITER Organization.

For more information, see our Privacy policy.

News & Media

Latest ITER Newsline

  • Image of the week | The platform's quasi-final appearance

    Since preparation work began in 2007 on the stretch of land that was to host the 42-hectare ITER platform, regular photographic surveys have been organized to d [...]

    Read more

  • Cryopumps | Preparing for the cold tests

    Before being delivered to ITER, the torus and cryostat cryopumps are submitted to a  comprehensive series of factory acceptance tests. This is not sufficie [...]

    Read more

  • Fusion technologies | Closing a fusion schism

    Historically, inertial confinement and magnetic confinement approaches to fusion have been parallel, separate processes. The ITER Private Sector Fusion Workshop [...]

    Read more

  • Toroidal field coil celebration | "A good day for the world"

    A little before 2:00 a.m. on 17 April 2020 a powerful transport trailer, accompanied by dozens of technical and security vehicles, passed the gates of the I [...]

    Read more

  • Press conference | New baseline to prioritize robust start to exploitation

    At a press conference on 3 July attended by approximately 200 journalists and key ITER stakeholders, ITER Director-General Pietro Barabaschi answered questions [...]

    Read more

Of Interest

See archived entries

The radio power house

The steel structure that's being erected against the northeast side of the Assembly Hall is for a large building that will be densely packed with power supplies and energy convertors designed to deliver 40 MW of heating power into the ITER plasma.

Originally planned for installation in the Assembly Hall, ICRH and ECRH equipment (power supplies and generators) will now have a building of its own. It's a more optimized solution in terms of both cost and schedule, allowing work on the installation of the systems to begin at an earlier date. (Click to view larger version...)
Originally planned for installation in the Assembly Hall, ICRH and ECRH equipment (power supplies and generators) will now have a building of its own. It's a more optimized solution in terms of both cost and schedule, allowing work on the installation of the systems to begin at an earlier date.
The space inside the building will be shared by two radio-wave-generating systems designed to feed energy at frequencies that match the oscillations of the different particles inside the plasma—a matching called "resonance."

Deuterium and tritium nuclei, or ions, will be "heated" by ion cyclotron resonance heating (ICRH); while electrons will be "heated" by electron cyclotron resonance heating (ECRH). By way of collisions, electrons will in turn transfer the absorbed energy to the ions.

In ITER, the ECRH system also generates the "spark" that, by ionizing the deuterium-tritium gaseous mix, starts up the plasma discharges.

Both heating systems are based on the same principle: the conversion of electrical power into electromagnetic radiation. However, the technology they rely upon and the wave frequencies they produce are considerably different—the ECRH system can be compared to a microwave oven, with the "food" replaced by the plasma, while the ICRH source is like a powerful radio transmitter of the kind that is still used to broadcast information from one end of the world to the other.

Both systems require considerable amounts of electrical power to operate. In the Radio Frequency Building, massive transformers and rectifiers will convert the industrial 22 kV AC into DC for the wave-generating gyrotrons of the ECRH system and for the tetrodes (akin to vacuum tubes) of the ICRH system.

The imposing building—50 metres long, 43 metres wide, 25 metres high—will be complete in early spring, allowing work to begin on added services. (Click to view larger version...)
The imposing building—50 metres long, 43 metres wide, 25 metres high—will be complete in early spring, allowing work to begin on added services.
The building is imposing—50 metres long, 43 metres wide, 25 metres high—but from the perspective of its future users it is barely large enough. Power supplies (a total input of 100 MW) for both resonance heating systems will occupy the better part of the first two floors, while the top floor will be occupied by the wave generators.

Generators too need a lot of space: on the ECRH side for example, twenty-four 2.5-metre-high gyrotrons —each giving out the equivalent power of 1,000 kitchen microwave ovens—must have an interspace of five metres between them in order to avoid magnetic interference.

Once generated in the Radio Frequency Building, the energetic radio beams must travel 100 metres along transmission lines all the way to the tokamak, where ECRH "launchers" and ICRH antennas—both massive components weighing up to 45 tonnes—will deliver them deep into the plasma.

Installing the sources at a distance from the machine is a choice dictated by magnetic issues: if they were any closer, the intense magnetic field of the tokamak would disrupt that of the generators' gyrotrons.

Over the next few months, the building will evolve rapidly. Soon, the internal floors and side walls will be added and by early spring the building structure will be complete, allowing work to begin on added services.

By mid-2018 the power supplies will be progressively installed, followed by the ECRH gyrotrons and ICRH tetrodes during the years 2019-2020.

See related article in this issue: "Men of measure."


return to the latest published articles