Listen to this story



A marvel in nuclear fusion reactor: ITER an impressive invention in engineering

Alvaro Salazar
9 min read

ITER ( International Thermonuclear Experimental Reactor ) is one of the most complex and goal-oriented enterprises facing humanity.

A marvel in nuclear fusion reactor: ITER an impressive invention in engineering
Nuclear fusion reactor: ITER

Its motivation is to reflect the cycles that allow stars to obtain energy by entangling the nuclei of their fuel, which is made up of around 70% protium, which is the isotope of hydrogen that needs neutrons and thus only has a single proton and an electron; between 24 and 26% helium, and between 4 and 6% synthetic components heavier than helium.

The point is that mimicking the atomic combination measurements that normally occur in the cores of stars is difficult.

Moreover, it is difficult, among many other reasons, because we do not have a really important ally that makes things much easier for the stars: gravitational repression.

Its mass is excessively colossal, so that gravity manages to pack the gases of the celestial center enough to reproduce normally the conditions in which the hydrogen nuclei begin to combine unexpectedly. This is the way stars get their energy.

A test like this requires a decent fix, and we have it.

We cannot reproduce these equivalent conditions on Earth, as we do not have the information or the innovation to control gravitational fields.

Nothing seems to show that something like this is conceivable later on, not to mention that we really want to produce a gravitational field really close to that of a star.

Consequently, to trigger the atomic combination we must choose the option of heating the fuel in our reactors until it reaches a temperature of between 150 and 300 million degrees Celsius, which, curiously, is several times higher than that of the center of the Sun.

Only in this way can the nuclei of deuterium and tritium, the isotopes of hydrogen that we use as fuel, can obtain the motive energy that is expected to overcome their normal aversion and wiring.

This is the objective of ITER

Supply 500 megawatts for no less than 500 s using only 1 g of tritium as a fuel component and subsequently start the reactor with about 50 megawatts of energy.

The ITER atomic combining reactor has been conceived to show that atomic combining on the scale that man can tackle works. And, in addition, that it is economically profitable from an energy point of view, since it creates more energy than it needs to contribute to initiate the interaction.

He plans to deliver around 500 megawatts of force for no less than 500 seconds using just 1 gram of tritium as the fuel characteristic and subsequently to put around 50 megawatts of power into tapping the combination reactor.

The machine created by a global consortium in Cadarache, France, is extraordinarily mind-blowing. In fact, presumably only CERN 's molecule locators rival ITER 's combined atomic reactor in design complexity.

A company of this size is only conceivable if the assets of the world's most important forces are brought together, prompting China, Japan, Russia, the European Union, the United States, India and South Korea to come together to make the amazing machine in which we are going to immerse ourselves.

The core of ITER is its Tokamak reactor. This plan was considered during the 1950s by Soviet physicists Igor Yevgenyevich Tamm and Andrei Sakharov, which warns us that we have been dealing with atomic combining, essentially according to a hypothetical perspective, for only about seventy years.

The hallmark of Tokamak reactors that allows anyone to recognize one initially is its donut shape.

The decision of this calculation, as we can guess, is not involuntary; it reacts to the need to limit the astonishingly hot fuel (in a plasma state) within it to reproduce the conditions essential for controlled combination responses to occur.

Everything at ITER is huge. Its complexity, but also its numbers. When finished, it will measure no less than 23,000 tons.

Awesome additional information

The sweep of the part of the "donut" in which the plasma is agglutinated estimates 6.2 meters, and the volume of the vacuum chamber containing the fuel at the immense temperature to which I referred in the primary passages of the product is of 840 m3.

This is the largest Tokamak reactor that humanity has ever made, and it will potentially be surpassed simply by the DEMO, whose development, according to the timetable set by EUROfusion, should be completed before the end of the next decade.

The cryostat

This part is a huge treated steel chamber that measures 29 x 29 meters, weighs 3,850 tons and has a volume of 16,000 m3.

It is responsible for providing the high vacuum important to create the conditions within the chamber for the combination of the deuterium and tritium nuclei that make up the high-temperature plasma.

The cryostat is also responsible for maintaining the supercool climate vital for superconducting magnets, which will be discussed later.

A couple of the many hundreds of openings that can be seen in its tube-shaped surface are used to complete maintenance tasks, but the vast majority of them are used to reach the cooling structure, analysis equipment or the cover that covers inside the reactor, between different applications.

The vacuum chamber

Like the cryostat, this 8,000-ton chamber is made of mild steel, although it also contains a modest amount of boron (around 2%).

Inside it, the combination of deuterium and tritium nuclei occurs, so one of its most significant capacities is to serve as the first regulatory obstacle for persistent radiation that will probably not be retained by the cover, an essential part that is will examine something later.

The vacuum chamber is hermetically fixed, and inside it is produced the high vacuum important for the combination of the plasma nuclei to take place.

Its toroidal shape contributes to the adjustment of the gas, so the cores rotate at high speed around the focal aperture of the chamber, although without ever coming into contact with the dividers of the torus.

The temperature at which this chamber is pressed is extremely high, so it is important to have circulating water in a compartment between its internal and external dividers to cool it and prevent it from reaching its highest temperature limit.

The magnets

The superconducting magnets placed outside the vacuum chamber are responsible for producing the field of attraction that is expected to bind the plasma inside.

They are also responsible for controlling and settling the plasma to prevent it from coming into contact with the compartment walls. These magnets weigh 10,000 tons and are made of a compound of niobium and tin, or of niobium and titanium, which acquires superconductivity when cooled with supercritical helium to a temperature of - 269 ° C.

The construction that can be seen above this section is the core of ITER 's attractive engine. Its round and hollow shape allows this superconducting solenoid to be placed within the focal aperture of the vacuum chamber, thus causing a gigantic electrical flux in the plasma.

In addition, this exceptionally incredible magnet is used to improve the condition of the plasma, settle it and, in addition, help to heat it thanks to an instrument known as a Joule impact, helping to raise its temperature above the 150 million degrees centigrade essential for it to be produce the atomic combination response. It is 18 meters high, 4 meters long and weighs 1,000 tons.


It is made of treated steel, although it casts tungsten safeguards that are responsible for withstanding the assault of high-energy neutrons from the plasma, changing its motive energy into heat.

The water circulating inside the diverter is responsible for supplying this nuclear energy and cooling the diverter. Tungsten was chosen to adjust the shields presented to the plasma, since it is the metal with the most notable softening point: not less than 3,422 ° C. In addition, the diverter is responsible for refining the plasma, allowing the expulsion of the residues and contaminations that are produced by the response of the atomic combination and the communication of the plasma with the most exposed layer of the mantle.

The mantle ("cover")

The construction that we can find in this image is the cover that lines up inside the vacuum chamber of the reactor. It is a basic part that is on the razor's edge, since it is presented to the immediate effect of the high-energy neutrons that are produced by the combination of the deuterium and tritium nuclei.

In addition, it will be used to recover the tritium to be used as fuel. For this, it is important to cover the inner layer of the mantle with lithium, a synthetic component that makes it possible to obtain tritium nuclei when the lithium nuclei are hit by high-energy neutrons.

The dynamic energy of the neutrons is transformed into nuclear energy upon impact with the mantle, and, once again, the water from the cooling frame is responsible for emptying this heat, which will be used by power plants to supply energy through a system basically the same as that used by splitting thermal power stations at the moment.

One last fascinating note to finish the article: the component of the substance that will form the most superficial layer of the mantle is beryllium, since its physicochemical properties allow it to withstand the pressure forced by the effect of neutrons better than other metals.

The deeper layers of the mantle are copper and treated steel, although the components used to make both the mantle and the diverter of things to come of the DEMO reactor could change if the specialists associated with the IFMIF-DONES project discover materials prepared to withstand better the immediate opening to the plasma to which these parts are subjected.