Elytt supply to F4E 400 OVCs

F4E has signed a contract worth 2 million EUR with Elytt Energy, for the manufacturing of more than 400 coils which will be installed on the outer surface of the ITER Vacuum Vessel. These coils will measure the magnetic field strength surrounding the ITER machine core, and will thus contribute to determination of key parameters such as the shape and position of the plasma inside, during reactor operations.

“This is a technically challenging task, as these coils must last the entire lifetime of ITER without maintenance, after their installation on the machine”, says Glenn Counsel, F4E´s Manager of the Diagnostics Team.

The Outer Vessel Coils are part of the ITER magnetics diagnostic. The location of these diagnostics on the exterior, rather than the interior, of the ITER Vacuum Vessel means tgat measurements are less accurate but advantageously more robust as they are much less exposed to neutrons released during the fusion reactions.

The Outer Vessel Coils (OVCs) are designed to measure the local equilibrium magnetic field at the outer surface of the ITER vacuum vessel, with a modest cut-off frequency of 50 Hz. These measurements will be ised to support reconstruction of the equilibrium magnetic field configuration and determination of several plasma parameters, including the plasma current. The OVCs will be installed on the external skin of the ITER vacuum vessel in several arrays distributed on the ITER machine.

Elytt Energy will be supplying coils in various sizes, with external dimensions in the range of 150-300 mm and thickness of 11 mm, to fti in the narrow space between the ITER Vacuum Vessel and its surrounding heat shields.

The ITER project aims to build a fusion device, twice the size of the largest current devices, with the goal of demonstrating the scientific and technical feasibility of fusion powe. It is a joint project between the European Union, China, India, Japan, South Korea, the Russian Federation and the USA. ITER will be constructed in Europe, at Cadarache in the south of France.

The sensors comprise enamel-insulated cable, wound on a ceramic former, enclosed in a inconel case which will be welded to stainless steel bosses previously welded to the ITER Vacuum Vessel.

The OVCs have a temperature survival range of 80K-493K, and will operate in the evacuated environment of the ITER cryostat. Careful control of materials used in the manufacture of the OVCs and their cleanliness will be important to ensure the OVCs do not adversely affect the quality of hte cryostat vacuum. Due to lack of access after installation, the sensor are required to operate throughout the operating life of ITER without maintenance.