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  • DISCOVERY | DA VINCI'S IMPOSSIBLE "TOKAMAK DRAWING"

    The exploration of the now-digitized Leonardo Da Vinci notebooks continues to amaze the worldwide scientific community. A few weeks ago, engineers at the Califo [...]

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  • Deputy Director-General | Yutaka Kamada, Science & Technology

    In his late childhood and early teens, Yutaka Kamada developed two passions: one for growing cactus, the other for fusion energy. Half a century later, his [...]

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  • Images of the week | Yet another magnet feeder from China

    This in-cryostat feeder will supply electrical power and cryogenic fluids to some of the top correction coils of the ITER machine. ITER will rely on 31 mag [...]

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  • Gyrotrons | India successfully demonstrates ITER power and pulse requirements

    As a part of its in-kind commitments to the project, ITER India will deliver two radio-frequency-based power sources (or 'gyrotrons") with state-of-the-art [...]

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  • Neutral beam power supply | Lightning-power voltage

    In January 2021, preparatory works began for the construction of two large buildings designed to accommodate a unique set of electrical equipment. A little more [...]

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Of Interest

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ITER NEWSLINE -

Manufacturing

Like a fire-breathing dragon

With the precision of a surgical tool, the plasma jet cuts through the thickness of the steel plate. As sparks fly, the large circular opening at the centre of the cryostat lid is bathed in pinkish-mauve light—the colour of the ultra hot (30 000 °C) hydrogen-nitrogen-argon plasma. Towering above the operator, the computer-controlled 10-tonne robot slowly moves its cutting head up one of the component's ribs, slicing through steel like a thread through butter. One by one, the ribs are machined in order to align perfectly with the edge of the opening.

The large circular opening at the centre of the cryostat lid is bathed in the pinkish-mauve light of the plasma-cutting robot. The machine is seen here slicing through the steel of one of the vertical ribs that strenghten the lid's structure. (Click to view larger version...)
The large circular opening at the centre of the cryostat lid is bathed in the pinkish-mauve light of the plasma-cutting robot. The machine is seen here slicing through the steel of one of the vertical ribs that strenghten the lid's structure.
The plasma machining underway on the central part of the top lid, where a central cylinder will soon be fitted and welded, is the most spectacular of the ongoing works in the Cryostat Workshop. While the dragon-like robot breathes its fire through the steel, a dozen welders from contractor MAN Energy Solutions are busy finalizing the radial joints between the component's segments, and an operator from the Indian manufacturer Larsen & Toubro Ltd, under the constant supervision of a quality inspector, performs ultrasonic tests on the completed welds.

Precisely aligned, the nozzle of the robot's cutting head delivers a super heated jet of hydrogen-nitrogen-argon plasma (30,000 °C) that slices through steel like a thread through butter. (Click to view larger version...)
Precisely aligned, the nozzle of the robot's cutting head delivers a super heated jet of hydrogen-nitrogen-argon plasma (30,000 °C) that slices through steel like a thread through butter.
"At this point, approximately 50 percent of the welding is done and 4 out of 12 radial joints have been checked by ultrasound," explains Anil Bhardwaj, ITER Cryostat Advisor. The operation is long and delicate: every radial joint must be leak-tested on both surfaces (top and underside) of the steel plate and the process takes about two days. After all welds have passed this first round of testing, helium leak tests, scheduled in mid-October, will demonstrate that the top lid, like the three other sections of the 8,500 m³ cryostat, is leak-tight as can be.

Every radial joint must be leak tested on both surfaces of the steel plate (top and underside), a process that takes about two days. 50% of the welding is now finalized. (Click to view larger version...)
Every radial joint must be leak tested on both surfaces of the steel plate (top and underside), a process that takes about two days. 50% of the welding is now finalized.
At 665 tonnes, the cryostat top lid is the second heaviest single component of tokamak assembly. "With the base, it is also the most critical part of the cryostat," adds Anil. "Its shape is particularly complex, the amount of welding is considerable and access is not always easy."

Like a roof on a house, the installation of the cryostat top lid will mark the completion of core machine assembly.

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