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

  • Vacuum components | Shake, rattle, and... qualify!

    A public-private testing partnership certified that ITER's vacuum components can withstand major seismic events. Making sure the ITER tokamak will be safe in th [...]

    Read more

  • Feeders | Delivering the essentials

    Like a circle of giant syringes all pointing inward, the feeders transport and deliver the essentials to the 10,000-tonne ITER magnet system—that is, electrical [...]

    Read more

  • Image of the week | It's FAB season

    It's FAB season at ITER. Like every year since 2008, the Financial Audit Board (FAB) will proceed with a meticulous audit of the project's finances, siftin [...]

    Read more

  • Disruption mitigation | Final design review is a major step forward

    The generations of physicists, engineers, technicians and other specialists who have worked in nuclear fusion share a common goal, dedication and responsibility [...]

    Read more

  • Image of the week | Like grasping a bowl of cereal

    Contrary to the vast majority of ITER machine components, the modules that form the central solenoid cannot be lifted by way of hooks and attachments. The 110-t [...]

    Read more

Of Interest

See archived entries

ITER NEWSLINE -

Cryodistribution

Blowing cold and hot

If the cryodistribution system were a railroad, the cryogenic termination cold box would be its main switch. A massive structure packed with pipes, valves, electrical feedthroughs and pneumatic actuators, the termination cold box collects the cooling fluids from the cryoplant and redirects them to the Tokamak Building over an elevated bridge. Once inside the building, another set of smaller cold boxes, called "auxiliary" boxes, dispatches the fluids to their different clients— supercritical helium at 4.7 K to the magnets and cryopumps, gaseous helium at 80 K to the thermal shield.
 
ITER technical responsible officer Hyun Sik Chang (right) and a technician from the Swiss company Linde Kryotechnik AG, perform the cleanliness check protocol on the box's multiprocess cryolines. (Click to view larger version...)
ITER technical responsible officer Hyun Sik Chang (right) and a technician from the Swiss company Linde Kryotechnik AG, perform the cleanliness check protocol on the box's multiprocess cryolines.
During operation, the ITER superconducting magnet system (all 10,000 tonnes of it), the cryopumps and the thermal shield must be kept at cryogenic temperature. But when maintenance is scheduled, this huge mass of frigid components must be brought back up to room temperature.
 
 "Because of the considerable mass of the superconducting magnets, and of the quality of the  machine's vacuum insulation, it would take several weeks for the ultra-cold components to warm up and allow maintenance," explains David Grillot, the head of ITER Cryogenic System Section. Hence the second mission of the cryogenic termination cold box: to bring the magnets and their environment to room temperature.
 
Procured by ITER India and manufactured by the Swiss company Linde Kryotechnik AG, the cryogenic termination cold box is a massive structure packed with pipes, valves, electrical feedthroughs and pneumatic actuators. (Click to view larger version...)
Procured by ITER India and manufactured by the Swiss company Linde Kryotechnik AG, the cryogenic termination cold box is a massive structure packed with pipes, valves, electrical feedthroughs and pneumatic actuators.
Magnets are maintained at cryogenic temperature by a constant flow of supercritical helium (neither liquid nor gaseous, but a bit of both) from the cryoplant systems. When the time comes to warm up the machine, the cooling fluid from the cryoplant is diverted to a parallel circuit that takes it through a set of powerful electrical heaters before being blown into the magnets.
 
"Let's say that instead of continuing to blow very cold, we blow warmer and warmer, with small increments on the order of one degree per hour in order to prevent mechanical constraints," says Grillot. "Progressively, over the course of a few days, the magnets' temperature rises from that of a winter night on Pluto to that of a balmy spring day in Provence, and the machine become accessible for maintenance operations."
 
Bringing the temperature inside the machine from that of a winter night on Pluto to that of a balmy spring day in Provence. Pictured: David Grillot, the head of ITER Cryogenic System Section. (Click to view larger version...)
Bringing the temperature inside the machine from that of a winter night on Pluto to that of a balmy spring day in Provence. Pictured: David Grillot, the head of ITER Cryogenic System Section.
Procured by ITER India, the cryogenic termination cold box is manufactured by the Swiss company Linde Kryotechnik AG. Installation in the cryoplant began in early July and should be completed by the end of this month.

return to the latest published articles