ITER, the world’s largest international scientific collaboration, is beginning assembly of the fusion reactor tokamak that will include 12 different essential hardware systems provided by US ITER, which is managed by Oak Ridge National Laboratory.

The soup-bowl-shaped base of the ITER cryostat was gradually lifted from its frame, carried across the Assembly Hall to the Tokamak Building and eventually lowered into the Tokamak assembly pit. The operation marked the culmination of a ten-year effort to design, manufacture, deliver, assemble and weld one of the most crucial components of the ITER machine—the 30-meter-high, 30-meter-in-diameter ITER cryostat (of which the base is only one part)—which will act as a thermos, insulating the magnetic system at cryogenic temperature from the outside environment.

Procured by India, manufactured in segments by Larsen & Toubro Ltd at its Hazira factory, the cryostat is assembled and welded on site under the supervision of the Indian Domestic Agency. The elements for the base section were delivered to ITER in December 2015 and the 1,250-tonne component was finalized in July of last year. Taking over from the Indian Domestic Agency, the ITER Organization then proceeded with “pre-assembly work” before moving the component into the Assembly Hall one month ago.

The 1250-ton cyrostat base is positioned over the ITER tokamak pit for installation. This base is the heaviest lift of tokamak assembly. Credit: ITER Organization

The systems include superconductors for the toroidal field magnet system and ORNL-developed pellet injection technology for plasma fueling and performance. These critical components will help ITER achieve its mission to demonstrate a self-heated, burning plasma and 500 megawatts of fusion power.

The 60-foot-tall central solenoid magnet, also fabricated under ORNL management, is considered the “heart of ITER” because it will initiate and drive plasma current inside the tokamak.

The first shipment of central solenoid modules to ITER, located in southern France, will begin later this year.