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ITER fusion energy

Fusion, the nuclear reaction that powers the sun and the stars, a potential source of safe, carbon-free, and practically limitless energy.

Somni sensors for fusion energy


Nuclear fusion energy could play a crucial role in tackling climate change and meeting future energy needs.


If nuclear fusion can be successfully harnessed for energy production, it could be an almost limitless, carbon-free source of energy with minimal long-term radioactive waste compared to nuclear fission reactors.


There are several fusion reactions that can occur, but the most promising for practical energy production is the fusion of deuterium and tritium nuclei. The reaction produces a helium nucleus, a neutron and a large amount of energy.


There are many international research projects dedicated to achieving controlled nuclear fusion, some of the most prominent being ITER (International Thermonuclear Experimental Reactor) in France, which is a large-scale tokamak experiment. Other experiments based on the tokamak principle include JET (Joint European Torus) at Culham in the United Kingdom and JT-60SA: Located in Naka, Japan, it is part of Japan's contribution to the ITER project. Other developments include the National Ignition Facility (NIF): Located at the Lawrence Livermore National Laboratory in California, USA. It uses powerful lasers to compress and heat small fuel pellets containing deuterium and tritium.    


What is ITER?


ITER is one of the most ambitious energy projects in the world today.


In the south of France, 35 nations are working together to build the world's largest tokamak, an experimental machine designed to harness the energy of fusion. Inside this vessel, the energy produced by the fusion of atoms is absorbed as heat in the walls. A fusion power plant will use this heat to produce steam and, later, electricity through turbines and generators, just like a conventional power plant.


ITER will be the first fusion device to produce net energy and to sustain fusion over long periods of time. ITER will also be the first fusion device to test the integrated technologies, materials and physics regimes required for the commercial production of fusion-based electricity.


Somni has had the opportunity to contribute to this amazing innovation with three ground-breaking sensors.

Project 1:

ITER beamline: temperature and acceleration sensors


The tokamak requires nine support systems for its operation. Three of these systems are needed to raise the temperature of the plasma to thermonuclear temperatures and to control or maintain the plasma current, which is essential for the operation of the Tokamak. One of these systems is the beamline module.


There are nine Neutral Beamline Injection Modules, which provide most of the plasma heating and current drive power. Each of these neutral beamline modules produces up to 10 MV of extremely high energy atoms. By injecting these atoms through tangential access ports into the torus (doughnut shaped chamber), the plasma temperature is raised to fusion temperatures and also drives some of the plasma current.


Somni's accelerometers and temperature sensors are installed along these beamline modules.


Developing fiber optic accelerometers and temperature sensors that can withstand radiation, vacuum and high temperature environments is quite a challenge, but Somni has done it!

Project 2:

ITER- Port plugs acceleration sensors

Stainless steel stoppers weighing up to 48 tonnes will seal each opening to the ITER vacuum chamber.


Not only are they massive, they are also very complex. These port plugs protect and support some of the machine's most valuable payloads. These include diagnostic and heating system elements that are crucial to the tokamak's efficient operation.


Acceleration sensors play a critical role in ensuring the safe and reliable operation of the ITER port plugs by monitoring structural integrity, detecting shocks, facilitating performance optimisation and enabling adaptive control mechanisms for the port plugs and associated components.


Somni has the opportunity to develop accelerometers for the upper and equatorial port plugs!


These accelerometers are required to operate for many years without maintenance in a fairly harsh EMI, radiation, thermal and vacuum environment: The accelerometers had to be EMI insensitive, robust, made of high temperature and vacuum resistant materials and well cooled by thermal conduction to dissipate the nuclear heat.

Project 3

Port plugs strain sensors

Strain sensors are also essential tools for ensuring the safety, reliability and performance of the ITER port plugs. They provide critical data for structural monitoring, safety assurance and validation of numerical models, contributing to the successful operation of the fusion reactor.


Somni has been given the challenge of developing strain sensors for the upper and equatorial port plugs!


In addition to all the requirements such as environmental conditions, mechanical compatibility, radiation hardness, calibration and maintenance, as well as documentation and quality assurance, ITER also places extremely high demands on the sensitivity and temperature stability of these rosette strain sensors.

Somni Corporation bv

Rotterdamseweg 183C

2629 HD Delft

The Netherlands

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