Subscribe options

Select your newsletters:


Please enter your email address:

@

News & Media

Latest ITER Newsline

  • Computer-Aided Design | A new platform with Australia

    In September 2016, the signature of a Cooperation Agreement between the Australian Nuclear Science and Technology Organisation (ANSTO) and the ITER Organization [...]

    Read more

  • Ten years later | A prodigious adventure

    ITER began its existence as an aspiration in the early 1980s, as actors in the fusion community called for the joint machine that would demonstrate the feasibil [...]

    Read more

  • Image of the week | An impromptu visit

    Afteraddressing the UN Climate Change Conference on 15 November, French President Emmanuel Macron toured thecolourful COP23 exhibition zone. It was towards the [...]

    Read more

  • Cryoplant | How to install a compressor

    In order to properly install a helium compressor skid on its concrete pad, you need to start with a large push broom to sweep away the dust that inevitably accu [...]

    Read more

  • Magnetic system | Nine rings to fight the force

    Work on the pre-compression ringsof the ITER magnet system progresses in Europe, where work on a full-scale prototype is underway. These technically challenging [...]

    Read more

Of Interest

See archived articles

Designing the world's largest high vacuum chamber

Sabina Griffith

 (Click to view larger version...)
With the conclusion of the preliminary design review, the ITER cryostat passed another big milestone last week. Following the conceptual design review performed in November 2009, the review panel chaired by Felix Schauer from the Max Planck Institute (IPP) in Garching, Germany, once more went through all the design documents necessary for the Procurement Arrangement and looked at all the interfaces with other machine parts with special focus on in-vessel maintenance issues.

The ITER cryostat will be the world's largest high vacuum chamber. It is a single wall cylindrical vacuum vessel, with a vertical axis, a flat bottom and a tori-spherical top lid. Its internal diameter is about 28 metres, it's height is about 29 metres. It will hold a volume of about 8,500 m³.

Though it has to hold a high vacuum with a pressure of 1x10-4 Pa, the ITER cryostat  will have about 200 penetrations in total. Most of them are small and provide the supply of power, water or helium for the in-cryostat components. Twenty-three of the penetrations are slightly larger in order to allow human access for maintenance reasons. The biggest "hole" in the cryostat (10 metres in diameter) is the top lid that can be taken off in case the central solenoid magnet needs to be exchanged.

"The main issue at the preliminary design review was to make sure that all the requirements concerning the design are fulfilled, but also that the enormous amount of interfaces to other components and the outside world are clearly defined," explains  Felix Schauer. Naturally, it had also to be checked whether the manufacturing of the components, assembly and later maintenance of the cryostat can be done in a robust way with reasonable effort, and in conformance with all the requirements.

"Even though I come from a large and certainly complex fusion project—the stellarator Wendelstein 7-X in Greifswald, Germany—it was quite impressive when I got in such close contact to the huge ITER cryostat," Schauer comments. "However, the particular challenge for the ITER design as compared to other fusion experiments is not just its size but the fact that it is a nuclear machine and thus everything from design to operation and later decommissioning has to obey corresponding rigorous nuclear regulations."

Since this was a preliminary design review, it is evident that not all detailed questions can be solved at this point. Open issues were lively discussed, and corresponding "chits," i.e., written questions, comments and recommendations, were raised by the members of the meeting. At the end, the review panel came to the conclusion that the cryostat has a sound design and can be built and assembled as it is envisaged. Open issues like completion of some design documents, detailing of interface specifications or special calculations will not significantly influence the design and will be settled before the final design review. Due to the committed and active cooperation of the meeting members, this preliminary design review was a very fruitful event in a pleasant atmosphere. 


return to the latest published articles