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

  • 30th ITER Council: Progress in a time of challenge and transition

    The Council chamber on the fifth floor of the ITER Headquarters building resonated once again with the sound of voices as Member representatives gathered for th [...]

    Read more

  • Open Doors Day | Back together again

    After more than two years, ITER has resumed a tradition that dates back to 2007—Open Doors Day. On Saturday 18 June, more than 50 "volunteers," staff [...]

    Read more

  • ITER Robots | Cultivating curiosity and creativity

    Robotics are everywhere. As technology develops, robots are playing an increasing role in industry, medicine, agriculture and many other fields. In ITER, the op [...]

    Read more

  • Worksite | Changing views

    Twelve years after construction work began on the ITER platform, the installation has acquired its near-final appearance. More than 85 percent of civil works ar [...]

    Read more

  • Image of the week | A steep climb

    In the days and weeks to come, the sector module that was installed in the Tokamak assembly pit on 11-12 May will be moved closer to its final position. Hydraul [...]

    Read more

Of Interest

See archived entries

Welding

Cryostat base and lower cylinder are now one

Procured by India, the ITER cryostat is composed of four sections: the base, the lower and upper cylinders, and the top lid. Once positioned inside the assembly pit, the different sections are welded together in order to form the perfectly leak-tight vacuum chamber that will act as a thermos, insulating the ultra-cold superconducting magnets from the outside environment.

The welding of the lower cylinder to the cryostat base began in October 2020 and was completed in the last week of March 2021. ''Throughout this six-month operation we were never outside tolerance,'' says mechanical engineer Vikas Dube. (Click to view larger version...)
The welding of the lower cylinder to the cryostat base began in October 2020 and was completed in the last week of March 2021. ''Throughout this six-month operation we were never outside tolerance,'' says mechanical engineer Vikas Dube.
Protected in a sealed cocoon, the upper cylinder has been in storage on the platform since April 2020. The cryostat base was lowered into the pit in May 2020, followed by the lower cylinder in August. As for the top lid, its 12 segments are being assembled and welded in the Cryostat Workshop.

The first in-pit welding operation—the welding of the lower cylinder to the cryostat base—began in October 2020 and lasted six months, including testing. Like all previous cryostat welding operations, it was performed by India's contractor MAN Energy Solutions (sub-contractor of cryostat segment manufacturer Larsen & Toubro).

Following a first phase of root welding by way of a technique known as "double operator" welding (one working from the inside, the other from the outside), nine specialists continued working simultaneously on the 90 metres of circumference, using more than 1.5 tonnes of filler material in the process.

Distortion monitoring was performed on a regular basis by way of 50 metrology targets distributed on the inner surface of the components. "Because of the heat that the welds generate, deformation inevitably occurs, but we have ways to minimize that. Margins are included by manufacturing design and throughout this six-month operation we were never outside tolerance," says Vikas Dube, a mechanical engineer in ITER In-Cryostat, Cryostat Thermal Shield, Auxiliaries Section.

A weld, however, is not considered final until it is tested. Beginning with visual inspection, the non-destructive examination process implements a series of tests ranging from the simple, like dye penetrant test examination, to the ultra-sophisticated like helium leak tests.

The final check consists of a dimensional inspection that compares the data from the welded components to the data that was recorded before the start of welding, as well as to the requirements from the manufacturing drawings. There again, "everything was within the limits," says Vikas.



return to the latest published articles