Fusione di nuclei di idrogeno

Magnetic confinement fusion: energy that imitates the stars

A safe, sustainable and inexhaustible source of energy: a breakthrough in the path to decarbonization.


Fusing two hydrogen nuclei releases an enormous amount of energy. It is the type of nuclear reaction that in nature powers the sun and other stars. Its great advantage is that it does not emit greenhouse gases, heavily polluting or highly radioactive substances, which makes it very attractive as an energy source. On the downside, it's very difficult to replicate the process artificially on earth, because it means generating plasma at extremely high temperatures of millions of degrees. To reproduce it and make it usable, they're looking into magnetic confinement technology, which, as its name suggests, uses incredibly powerful magnetic fields to control the plasma that hosts the fusion. The plasma forms from the nuclei of two hydrogen isotopes, deuterium and tritium. These nuclei each hold a proton and one or two neutrons. The sun, however, uses protium, the most abundant hydrogen in the universe by a long chalk (99.98%), which contains no neutrons whatsoever. In any case, whatever their form, two hydrogen nuclei fused together produce energy, neutrons and helium, a noble gas that is utterly harmless. In other words, they make energy with zero impact, which is why we're focusing on magnetic confinement fusion and collaborating with big public and private research bodies to develop it. We see it as a milestone on the path to decarbonization

Fission or fusion?

Magnetic confinement nuclear fusion has the potential to become an unlimited energy source with a low environmental impact. It is a completely different technology from the nuclear fission that occurs in nuclear plants currently in operation in France, Germany, the United States, Russia, China and several other foreign countries.
In nuclear fission, isotopes of very heavy elements such as uranium are hit by neutrons and fragment producing lighter elements, releasing some neutrons and a large quantity of energy.
In nuclear fusion, on the other hand, isotopes of hydrogen - the lightest element in the Mendeleev Table - are fused together to produce helium, a neutron and a massively greater amount of energy.


Magnetic confinement fusion heralds a true revolution in energy because, once in use in industry, it will provide a clean, safe and practically inexhaustible energy source. Studying, designing and building machines that can oversee physical reactions similar to those at the core of stars is the technological dream that the greatest minds in the world of energy research are striving for. We realise the strategic importance of taking part in this challenge, which is why since 2018 we've been working with Commonwealth Fusion Systems (CFS), a spin-out company of the Massachusetts Institute of Technology (MIT), to build the prototype for a reactor that should be up and running in 2025. It will be christened SPARC and capable of controlling and confining plasma, or rather mixtures of deuterium and tritium, subjected to incredibly high temperatures by electromagnetic fields to create the conditions for controlled fusion. Relying on the set of skills we've gained through our experiments, we will go on to design and create ARC, the first reactor that can put energy from fusion on the grid.

The pathway

In September 2021, CFS successfully completed the first test to demonstrate the efficacy of innovative superconductor magnets for plasma confinement of hydrogen isotopes at temperatures of over 100 million degrees. This superconductor technology is essential to obtain magnetic fields of sufficient intensity to keep the plasma inside the reactor.
It uses a magnet made up of ReBCO (Rare Earth, Barium and Copper oxides) high temperature superconductors weighing around 10 tonnes which, when brought to -253°C (20 degrees above absolute zero) and crossed with an electric current of an intensity of 40,000 Amps, produces a field with a magnetic flux density equal to 20 Tesla.
This is fundamental milestone on the path to constructing a much more compact, simple and efficient experimental fusion reactor compared to those that use more traditional low-temperature superconductors.

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SUPERFAST#3 - Goal: clean energy

Technological challenge

Fusion happens when two nuclei from hydrogen isotopes come close enough together to unite and form a new, heaver element, like helium. But to fuse two particles with the same charge, which therefore tend to repel each other electrostatically, it takes temperatures of hundreds of millions of degrees. Thermal agitation lets fusion take place inside a gas at a very high temperature called plasma. The main technical hurdle to get over is managing this fiery plasma, which has to be kept confined in a limited space and suspended in air, to stop it cooling down or damaging the plant around it. To do this, you have to use Tokamak, a doughnut-shaped device in whose magnetic field, generated by coils within the chamber, plasma floats about rather than coming in contact with the internal walls. Hence the name of the technology: magnetic confinement fusion. To develop it, we formed big partnerships with CFS, MIT, CNR and ENEA. With CNR we are studying new materials for superconductors, while at ENEA's centre in Frascati we will be carrying out the Divertor Tokamak Test (DTT), to create an experimental machine to test technical solutions and give responses on how to manage parts of the fusion process, like the very high temperatures. These studies will integrate the work connected to the International Thermonuclear Experimental Reactor (ITER) project, begun in 2005, to which the European Union, Russia, the United States, Japan, China, South Korea and India are signed up. This project involves building a big fusion reactor like Tokamak in Cadarache, in the South of France, which should be ready by 2025. This initial plant will set the foundations for building DEMO in 2050, a demonstration reactor for putting energy on the grid. SPARC will be five times less powerful than ITER but 65 times smaller, and thanks to new superconductor materials, used to make magnets, will be able to work in magnetic fields four times stronger.

Industrial integration

Developing magnetic confinement fusion is a global challenge that will involve a wide range of international talent in industrial science and technology. Everyone will have to put his skills and experience to use in the service of this revolutionary technology. At Eni, besides working with big research bodies, we have handed our HPC5 supercomputer to researchers, who will use its huge calculating power for highly complex mathematical models that will describe the physics of plasma and simulate its behaviour. When we get fusion to a mature enough point that it can be used in industry, the stage will be set for unprecedented things. We will finally have a widespread supply of clean, safe, sustainable energy. Power stations fed by fusion reactors could meet the growing demand for energy at big production and population centres while maintaining high sustainability. Smaller stations, on the other hand, integrated with renewable sources, could make it easier to provide energy to small communities and off-grid businesses.

Environmental impact

The energy produced in the fusion process is virtually infinite, is safe and releases no emissions of climate-altering gases or pollutants whatsoever. Consider that to get the same energy produced by 8,500 tonnes of petrol, you need just 1 kg of “fusion fuel”, which has the added benefit of not releasing any greenhouse gases The road to this technological revolution is long, but by taking it we are heading for a more sustainable future.