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

  • Test facility | How do electronics react to magnetic fields?

    A tokamak is basically a magnetic cage designed to confine, shape and control the super-hot plasmas that make fusion reactions possible. Inside the ITER Tokamak [...]

    Read more

  • ITER Robots | No two alike

    More than 500 students took part in the latest ITER Robots challenge. Working from the same instructions and technical specifications, they had worked in teams [...]

    Read more

  • Data archiving | Operating in quasi real time

    To accommodate the first real-time system integrated with the ITER control system, new components of the data archiving system have been deployed. Data archivi [...]

    Read more

  • Repairs | Setting the stage for a critical task

    Like in a game of musical chairs—albeit in slow motion and at a massive scale—components in the Assembly Hall are being transferred from one location to another [...]

    Read more

  • Image of the week | There is life on Planet ITER

    Dated April 2023, this new image of the ITER "planet" places the construction site squarely in the middle. One kilometre long, 400 metres wide, the IT [...]

    Read more

Of Interest

See archived entries

Tore Supra looking WEST for the second ITER divertor

Tore Supra might help to deliver answers for the second divertor set foreseen for the nuclear phase of ITER. (Click to view larger version...)
Tore Supra might help to deliver answers for the second divertor set foreseen for the nuclear phase of ITER.
During the non-active phases of operation, ITER will use a divertor with carbon and tungsten plasma-facing material. Carbon is the reference design solution for the lower part of the divertor targets due primarily to a long history of experience in present and past tokamaks. Beginning with a carbon target is considered to have several advantages for the start of ITER operations, given its proven range of compatibility with a number of plasma conditions in present devices, particularly at low densities with significant additional heating. Its use will considerably ease the development of techniques for the control and mitigation of plasma instabilities (edge localized modes and disruptions) which, even in the lower power conditions characteristic of the non-active phases of ITER operation, can generate heavy heat pulse transients.

Unlike carbon, which sublimes, tungsten melts and there is a real concern that the very short duration, high heat fluxes that can be deposited during these transients will yield deformations of the precise material surfaces, compromising subsequent operation.

Largely due to the high level of tritium retention expected as a consequence of fuel co-deposition with carbon eroded from divertor target surfaces, ITER intends to replace the first carbon/ tungsten divertor with an all-tungsten variant before the start of the deuterium and deuterium-tritium plasma operation phases. However, the required high heat flux tungsten technology has never been tested in the demanding environment of a tokamak under the steady state plasma heat fluxes (~10-20 MWm-2) expected on divertor surfaces during ITER fusion plasma operation. Moreover, the fabrication of the ITER divertor with full-tungsten armour in the high heat flux strike point regions, represents an unprecedented technological challenge.

The panel during the review meeting of 8 December 2010 at Cadarache. © CEA/Patrice Fiet (Click to view larger version...)
The panel during the review meeting of 8 December 2010 at Cadarache. © CEA/Patrice Fiet
In order to reduce the risks and anticipate any difficulties ITER may face in terms of manufacturing or operation, the CEA IRFM laboratory, ITER's neighbour on the Cadarache site, has recently proposed to equip Tore Supra with a full tungsten divertor, benefitting from the unique long pulse capabilities of the Tore Supra platform, the high installed power and the long history of operation with actively cooled, high heat flux components. Since Tore Supra is a circular plasma device, operating with a full toroidal limiter surface, the proposed upgrade requires that the device be equipped with some additional in-vacuum vessel magnetic coils to allow the production of divertor plasma shapes, just like those which ITER and all other divertor tokamaks use.

This tungsten divertor project, named "WEST" (acronym derived from W Environment in Steady-state Tokamak, where W is the chemical symbol for tungsten), promises to bring answers in a timely manner for the second divertor set foreseen for the nuclear phase of ITER.

A feasibility study of the WEST project was launched on 25th February 2010 and has involved about 40 people. About 500 components with a total of 15,000 tungsten tiles are planned to be manufactured with a fully relevant ITER design and technology.
The 164-page Feasibility Report was the basis for a peer review held at CEA Cadarache on 8 December 2010. An international review panel was called by CEA and was chaired by Prof. Minh Quang Tran (CRPP-EPFL, Lausanne, Switzerland). It comprised experts from Europe, China, the US and from the ITER Organization. The conclusions of the panel will be delivered early next year.


return to the latest published articles