The most grandiose scientific building of our time. As in France, a thermonuclear reactor ITER

Such a reactor costs five times more than the Large Hadron Collider. Hundreds of scientists from around the world are working on the project. Its financing can easily exceed 19 billion euros, and the first plasma reactor will be allowed only in December 2025. And despite constant delays, technological difficulties, insufficient funding from participating countries, the greater "thermonuclear perpetual motion machine" is being built. It has many more advantages than disadvantages. Which? The history of the most ambitious scientific construction of our time begins with the theory

What is a tokamak?

Under the influence of enormous temperatures and gravitation in the depths of our Sun and other stars, thermonuclear fusion takes place. Hydrogen nuclei collide, form heavier helium atoms and at the same time release protons and an enormous amount of energy

Modern science has concluded that the reaction between isotopes of hydrogen-deuterium and tritium produces the greatest energy. But for that, three conditions are important: high temperature (about 150 million degrees Celsius), high plasma density and high retention time

The fact is that we can not create a density as colossal as the Sun. It only remains to heat the gas in the state of plasma by means of very high temperatures. But no material is able to come into contact with such a hot plasma. To do this, Academician Andrei Sakharov (from the submission of Oleg Lavrentiev) in the 1950s suggested using a toroidal chamber (in the form of a hollow donut) with a magnetic field that would retain the plasma. Later, the term was coined – tokamak.

Modern plants, burning fossil fuels, convert mechanical energy (such as turbine twisting) into electricity. The tokamaks will use the energy of synthesis absorbed in the form of heat by the walls of the device, to heat and produce steam, which will turn the turbines.

Small experimental tokamaks have been built around the world. And they have successfully proven that a person can create a high temperature plasma and maintain it for a while in a stable state. The Advantages and Disadvantages of Fusion Reactors

Conventional nuclear reactors operate with dozens of tons of radioactive fuel (which turns into tens of tons of radioactive waste), while a thermonuclear reactor does not. needs only hundreds of grams of tritium and deuterium. . The first can be produced at the reactor itself: the neutrons released during the synthesis will act on the reactor walls with lithium impurities, from which tritium appears. Lithium reserves will last for thousands of years. In deuterium too, there will be no shortage – it is produced in the world by tens of thousands of tons per year.

The thermonuclear reactor does not produce greenhouse gas emissions, which is typical of fossil fuels. A by-product in the form of 4-helium is a harmless inert gas.

In addition, thermonuclear reactors are safe. In the event of a disaster, the thermonuclear reaction simply stops without serious consequences for the environment or the personnel, because there is nothing to support the synthesis reaction: it is too hot for it.

However, thermonuclear reactors have disadvantages. First of all, it's the bbad complexity of launching a self-sustaining reaction. She needs a deep emptiness. Complex systems of magnetic confinement require enormous superconducting magnetic coils.

And do not forget the radiation. Despite some stereotypes about the safety of thermonuclear reactors, the bombardment of their environment by the neutrons produced during synthesis is not canceled. This bombardment leads to radiation. Therefore, the reactor maintenance must be performed remotely. For the future, let's say that after the launch of the ITER tokamak, the robots will be engaged directly in the maintenance of the tokamak ITER

In addition, radioactive tritium can be dangerous when it is ingested. Admittedly, it will be enough to take care of its good storage and to create safety barriers on all possible paths of its distribution in case of accident. In addition, the half-life of tritium is 12 years old

When the necessary minimum foundation of the theory is laid, one can go to the hero of the article

The most ambitious project of modernity [19659004] The USSR and the United States. Prior to that, the cold war reached its peak: the superpowers boycotted the Olympics, increased their nuclear capabilities, and did not intend to negotiate negotiations. This summit of the two countries on the neutral territory is remarkable and another important circumstance. A year later, American, Soviet, European and Japanese scientists agreed on the project, the design of a large thermonuclear complex ITER began. The details of the engineering were delayed, the United States then left and then returned to the project, which eventually joined China, South Korea and India. Participants shared responsibilities for funding and direct work and in 2010, the foundation pit for the foundation of the future complex was finally launched. It was decided to build it in the south of France near the city of Aix-en-Provence

So, what is it that ITER? It's a vast scientific experiment and an ambitious energy project for the construction of the world's largest tokamak. The construction must prove the possibility of commercial use of a thermonuclear reactor, and also solve the emerging physical and technological problems along this path.

The Tokamak reactor is a toroidal vacuum chamber with magnetic coils and a cryostat weighing 23,000 tons. . As already clear from the definition, we have a camera. Deep vacuum chamber. In the case of ITER, it will be 850 cubic meters of the free volume of the chamber, in which it will initially have only 0.1 gram of mixture of deuterium and tritium [19659020] On the inner walls of the chamber are special modules called blankets. The water circulates inside them. Free neutrons escaping from the plasma enter these covers and are decelerated by the water. Because of what it is heated. The covers themselves protect the rest of the machine against the thermal radiation, X-rays and plasma neutrons already mentioned.

Such a system is necessary to prolong the life of the reactor. Each cover weighs about 4.5 tons, it will be changed by a robotic arm about every 5-10 years, since this first line of defense will be subject to evaporation and neutron radiation.

But that's not all. Intracameral equipment, thermocouples, accelerometers, already mentioned 440 blocks of cover system, cooling system, shielding unit, divertor, 48-element magnetic system, high frequency plasma radiators, neutral atom injector, etc. attached to the room. height of 30 meters, having the same diameter and volume of 16 thousand cubic meters. The cryostat guarantees a deep vacuum and an ultra-cold temperature for the tokamak chamber and the superconducting magnets, which are cooled by liquid helium at a temperature of -269 degrees Celsius

The production of all these equipments is distributed between the participating countries. For example, some of the blankets are working in Russia, on the body of the cryostat – in India, on vacuum chamber segments – in Europe and Korea.

But it's not a fast process at all. In addition, designers do not have the right to make a mistake. The ITER team first simulates the loads and requirements for design elements, tests on media (eg under the influence of plasma guns, as a divertor), improves and refines , collects prototypes and tests again before issuing the final element. collect And it's a whole other thing to serve all that. Due to the high level of radiation, access to the reactor was ordered. To support it, a whole family of robotic systems has been developed. The room will change the covers and cbadettes of the divertor (weighing less than 10 tons), some will be controlled remotely to eliminate accidents, some will be based in the pockets of the vacuum chamber with HD cameras and laser scanners for a quick inspection . And all this must be done in a vacuum, in a narrow space, with great precision and in clear interaction with all systems. The task is more complicated than repairing the ISS.

And this is only part of the equipment of the reactor itself. Add the cryogenic factory building, where they will produce liquid nitrogen and helium, a magnetic system rectifier with transformers, cooling pipes (diameter of 2 meters), a heat recovery system with 10 fans and much more.

Why is Iter necessary and who pays?

The ITER Tokamak will be the first thermonuclear reactor to produce more energy than necessary to heat the plasma itself. In addition, it will be able to keep it in a stable state much longer than current facilities. Scientists say that's the reason for being a large-scale project.

With the help of such a reactor, the experts will bridge the gap between the current small experimental facilities and the future fusion power plants. For example, a record of thermonuclear power was established in 1997 on a tokamak in Britain – 16 MW with 24 MW spent, while ITER was designed with an eye to 500 MW of thermonuclear power from 50 MW of thermal energy input. , control, diagnosis, cryogenics and remote maintenance, ie all the techniques required for an industrial sample of a thermonuclear reactor.

Global production volumes of tritium will not be sufficient for future power plants. ITER will therefore also develop the technology of a multiplied cover containing lithium. From here, under the action of thermonuclear neutrons, tritium will also be synthesized.

However, let 's not forget that it is as expensive, but an experience. The tokamak will not be equipped with turbines or other systems for converting heat into electricity. In other words, commercial programs in the form of direct energy production will not be. Why? Because it would only complicate the project from a technical point of view and make it even more expensive.

The funding system is rather confusing. At the stage of construction, the creation of the reactor and other systems of the complex, about 45% of the costs are borne by the EU countries, the remaining participants – by 9%. However, most of the contributions are "nature". Most components are shipped directly to the ITER of the participating countries.

They arrive in France by sea, and from the port to the shipyard are delivered on a road specially reworked by the French government. At 104 km "Ways ITER" the country has spent 110 million euros and 4 years of work. The route has been expanded and strengthened. The fact is that until 2021 250 convoys with huge cargoes will cross it. The heaviest details reach 900 tons, the highest – 10 meters, the longest – 33 meters

while ITER is not put into operation. However, there is already a project for the DEMO power plant on thermonuclear fusion, whose task is to demonstrate the attractiveness of the commercial use of the technology. This complex will need to generate 2 GW of energy continuously (rather than driven as ITER).

The timing of the implementation of the new global project depends on the success of ITER, but according to the plan for 2012, the first start will begin only in 2044.

селфи in the catalog Onliner .by

See also:

Our channel in Telegram.

Quick communication with the editorial board: read the public chat of Onliner and send us an email at Viber!

Reprinting text and photos from Onliner.by is prohibited without permission of the editorial office. [email protected]