Subscribe options

Select your newsletters:


Please enter your email address:

@

News & Media

Latest ITER Newsline

  • Magnets | CEA delivers ITER cryogenic instrumentation

    The ITER Organization has relied on the French CEA institute and its expertise in cryogenics and large superconducting magnets for the specialized instrumentati [...]

    Read more

  • Sector sub-assembly | Twin meets twin

    Although they were born one full year apart, they are identical twins: when the second vacuum vessel sector sub-assembly tool (SSAT-2) is complete, nothing will [...]

    Read more

  • R&D in Europe | Working with industry on digital hydraulics

    A contract signed with the European Domestic Agency is helping Finnish industry innovate in the domain of digital hydraulic valves. The result could interest IT [...]

    Read more

  • Diagnostics | What is the plasma shape? Ask the flux loop

    Inside the machine, the flux loop diagnostic will provide important information to operators on the boundary shape, energy and stability of the plasma. In ITE [...]

    Read more

  • Image of the week | Communicators of all countries, unite!

    ITER is a fascinating story to tell—how it began and how it developed, the challenges it has never ceased to face, the awe its infrastructure and components ins [...]

    Read more

Of Interest

See archived entries

Thermal shield

First 23 panels fit like clockwork

ITER Korea

During fitting trials in Korea, 23 stainless steel panels have been successfully pre-assembled into the first sector of vacuum vessel thermal shield.

As easy as that: the first 12-metre-tall sector of vacuum vessel thermal shielding was assembled in August from 23 stainless steel panels. One final operation—silver coating—remains to be completed before shipment to ITER. (Click to view larger version...)
As easy as that: the first 12-metre-tall sector of vacuum vessel thermal shielding was assembled in August from 23 stainless steel panels. One final operation—silver coating—remains to be completed before shipment to ITER.
In a major achievement for the thermal shield procurement program, the pre-assembly test on the vacuum vessel thermal shield sector #6 has been successfully completed at SFA Engineering Corp in Changwon, Korea. Technical responsible officers and engineers from the ITER Organization, the Korean Domestic Agency (ITER Korea) and SFA were there to witness the milestone, which took place in early August.

The purpose of the pre-assembly test was to demonstrate the feasibility of assembling the same sector of thermal shield at ITER. The test jig and fixture design (inboard frame, outboard frame) and the clamping conditions were identical to those that will be called into action as part of vacuum vessel sector sub-assembly activities in the ITER Assembly Hall beginning next year on the sector sub-assembly tool.

10- to 20-millimetre-thick sectors of thermal shielding will form an actively cooled barrier between the (warm) vacuum vessel and the (cold) magnets. This 40° segment was pre-assembled in August to test tolerances and to test the feasibility of assembly at ITER. (Click to view larger version...)
10- to 20-millimetre-thick sectors of thermal shielding will form an actively cooled barrier between the (warm) vacuum vessel and the (cold) magnets. This 40° segment was pre-assembled in August to test tolerances and to test the feasibility of assembly at ITER.
The vacuum vessel thermal shield is a 10- to 20-millimetre-thick barrier interposed between the vacuum vessel and the superconducting magnets. It will be actively cooled with gaseous helium at 80 K (minus 193 °C) to minimize the radiation heat load that is transferred by thermal radiation and conduction from warm components (vessel) to the components operating at 4.5 K (minus 269 °C) such as the magnets.

Each of the nine 40° sectors of vacuum vessel thermal shielding consists of 23 stainless steel panels, each with its own welded cooling tube. The pre-assembly test for sector #6 took place in four steps:

  1. Jig assembly of the outboard 10° segment, with dimensional inspection
  2. Jig assembly of the outboard 20° segment
  3. Jig assembly of inboard 40° segment, with dimensional inspection
  4. Jig assembly of inboard 40° segment and two outboard 20° segments, with dimensional inspection
Dimensional inspection of the shell was performed for the sub-assembled segments by 3D laser scanning.

Observers were also able to verify the tight tolerances (2 mm) that are required for the 1,800 bolt holes of the sector. "Nine hundred bolts and corresponding holes were verified and all the flanges were assembled well without gaps," says Dongkwon Kang, ITER technical responsible officer for the thermal shield. "This gives us confidence that there will be no critical interface issues for the assembly and the operation of the vacuum vessel thermal shield at the ITER site."

Vacuum vessel thermal shield sector #6 will now be dismantled for silver coating before being re-assembled into inboard and outboard segments for shipment to ITER. All is on schedule to meet the ITER Council milestone for delivery of the thermal shield sector by April 2019. 



return to the latest published articles