Recently, the Moscow Institute of Physics and Technology hosted a Russian presentation of the ITER project, within which it is planned to create a thermonuclear reactor operating on the tokamak principle. A group of scientists from Russia spoke about the international project and the participation of Russian physicists in the creation of this object. Lenta.ru attended the ITER presentation and spoke with one of the project participants.

ITER (ITER, International Thermonuclear Experimental Reactor) is a thermonuclear reactor project that allows the demonstration and research of thermonuclear technologies for their further use for peaceful and commercial purposes. The creators of the project believe that controlled thermonuclear fusion can become the energy of the future and serve as an alternative to modern gas, oil and coal. Researchers note the safety, environmental friendliness and accessibility of ITER technology compared to conventional energy. The complexity of the project is comparable to the Large Hadron Collider; The reactor installation includes more than ten million structural elements.

About ITER

Tokamak toroidal magnets require 80 thousand kilometers of superconducting filaments; their total weight reaches 400 tons. The reactor itself will weigh about 23 thousand tons. For comparison, the weight of the Eiffel Tower in Paris is only 7.3 thousand tons. The plasma volume in the tokamak will reach 840 cubic meters, whereas, for example, in the largest reactor of this type operating in the UK - JET - the volume is one hundred cubic meters.

The height of the tokamak will be 73 meters, of which 60 meters will be above the ground and 13 meters below it. For comparison, the height of the Spasskaya Tower of the Moscow Kremlin is 71 meters. The main reactor platform will cover an area of ​​42 hectares, which is comparable to the area of ​​60 football fields. The temperature in the tokamak plasma will reach 150 million degrees Celsius, which is ten times higher than the temperature at the center of the Sun.

In the construction of ITER in the second half of 2010, it is planned to involve up to five thousand people simultaneously - this will include both workers and engineers, as well as administrative personnel. Many of ITER's components will be transported from the port near the Mediterranean Sea along a specially constructed road approximately 104 kilometers long. In particular, the heaviest fragment of the installation will be transported along it, the mass of which will be more than 900 tons, and the length will be about ten meters. More than 2.5 million cubic meters of earth will be removed from the construction site of the ITER facility.

The total cost of design and construction works is estimated at 13 billion euros. These funds are allocated by seven main project participants representing the interests of 35 countries. For comparison, the total costs of building and maintaining the Large Hadron Collider are almost half as much, and building and maintaining the International Space Station costs almost one and a half times more.

Tokamak

Today in the world there are two promising projects of thermonuclear reactors: tokamak ( That roidal ka measure with ma rotten To atushki) and stellarator. In both installations the plasma is contained magnetic field, however, in a tokamak it takes the form of a toroidal cord through which an electric current is passed, while in a stellarator the magnetic field is induced by external coils. In thermonuclear reactors, reactions of synthesis of heavy elements from light ones (helium from hydrogen isotopes - deuterium and tritium) occur, in contrast to conventional reactors, where the processes of decay of heavy nuclei into lighter ones are initiated.

Photo: National Research Center “Kurchatov Institute” / nrcki.ru

Electricity in a tokamak it is also used for the initial heating of plasma to a temperature of about 30 million degrees Celsius; further heating is carried out by special devices.

The theoretical design of a tokamak was proposed in 1951 by Soviet physicists Andrei Sakharov and Igor Tamm, and the first installation was built in the USSR in 1954. However, scientists were unable to maintain the plasma in a steady state for a long time, and by the mid-1960s the world was convinced that controlled thermonuclear fusion based on a tokamak was impossible.

But just three years later, at the T-3 installation at the Kurchatov Institute of Atomic Energy, under the leadership of Lev Artsimovich, it was possible to heat the plasma to a temperature of more than five million degrees Celsius and hold it for a short time; Scientists from Great Britain who were present at the experiment recorded a temperature of about ten million degrees on their equipment. After this, a real tokamak boom began in the world, so that about 300 installations were built in the world, the largest of which are located in Europe, Japan, the USA and Russia.

Image: Rfassbind/ wikipedia.org

ITER Management

What is the basis for confidence that ITER will be operational in 5-10 years? On what practical and theoretical developments?

On the Russian side, we are fulfilling the stated work schedule and are not going to violate it. Unfortunately, we see some delays in the work being carried out by others, mainly in Europe; There is a partial delay in America and there is a tendency that the project will be somewhat delayed. Detained but not stopped. There is confidence that it will work. The concept of the project itself is completely theoretical and practically calculated and reliable, so I think it will work. Whether it will fully give the declared results... we'll wait and see.

Is the project more of a research project?

Certainly. The stated result is not the obtained result. If it is received in full, I will be extremely happy.

What new technologies have appeared, are appearing or will appear in the ITER project?

The ITER project is not just a super-complex, but also a super-stressful project. Stressful in terms of energy load, operating conditions of certain elements, including our systems. Therefore, new technologies simply must be born in this project.

Is there an example?

Space. For example, our diamond detectors. We discussed the possibility of using our diamond detectors on space trucks, which are nuclear vehicles that transport certain objects such as satellites or stations from orbit to orbit. There is such a project for a space truck. Since this is a device with a nuclear reactor on board, complex operating conditions require analysis and control, so our detectors could easily do this. At the moment, the topic of creating such diagnostics is not yet funded. If it is created, it can be applied, and then there will be no need to invest money in it at the development stage, but only at the development and implementation stage.

What is the share of modern Russian developments of the 2000s and 1990s in comparison with Soviet and Western developments?

The share of Russian scientific contribution to ITER compared to the global one is very large. I don't know it exactly, but it is very significant. It is clearly no less than the Russian percentage of financial participation in the project, because in many other teams there are a large number of Russians who went abroad to work in other institutes. In Japan and America, everywhere, we communicate and work with them very well, some of them represent Europe, some represent America. In addition, there are also scientific schools there. Therefore, about whether we are developing more or more what we did before... One of the greats said that “we stand on the shoulders of titans,” therefore the base that was developed in Soviet times is undeniably great and without it we are nothing we couldn't. But even at the moment we are not standing still, we are moving.

What exactly does your group do at ITER?

I have a sector in the department. The department is developing several diagnostics, our sector is specifically developing the vertical neutron chamber, ITER neutron diagnostics and decides big circle tasks from design to manufacturing, and also conducts related research work related to the development, in particular, of diamond detectors. The diamond detector is a unique device, originally created in our laboratory. Previously used in many thermonuclear installations, it is now used quite widely by many laboratories from America to Japan; they, let's say, followed us, but we continue to remain on top. We are now making diamond detectors and are going to reach the level of industrial production (small-scale production).

What industries can these detectors be used in?

In this case, these are thermonuclear research; in the future, we assume that they will be in demand in nuclear energy.

What exactly do detectors do, what do they measure?

Neutrons. There is no more valuable product than the neutron. You and I also consist of neutrons.

What characteristics of neutrons do they measure?

Spectral. Firstly, the immediate task that is solved at ITER is the measurement of neutron energy spectra. In addition, they monitor the number and energy of neutrons. The second, additional task concerns nuclear energy: we have parallel developments that can also measure thermal neutrons, which are the basis of nuclear reactors. This is a secondary task for us, but it is also being developed, that is, we can work here and at the same time make developments that can be quite successfully applied in nuclear energy.

What methods do you use in your research: theoretical, practical, computer modeling?

Everyone: from complex mathematics (methods of mathematical physics) and mathematical modeling to experiments. All the different types of calculations that we carry out are confirmed and verified by experiments, because we directly have an experimental laboratory with several operating neutron generators, on which we test the systems that we ourselves develop.

Do you have a working reactor in your laboratory?

Not a reactor, but a neutron generator. A neutron generator is, in fact, a mini-model of the thermonuclear reactions in question. Everything is the same there, only the process there is slightly different. It works on the principle of an accelerator - it is a beam of certain ions that hits a target. That is, in the case of plasma, we have a hot object in which each atom has high energy, and in our case, a specially accelerated ion hits a target saturated with similar ions. Accordingly, a reaction occurs. Let's just say this is one way you can do the same fusion reaction; the only thing that has been proven is that this method does not have high efficiency, that is, you will not get a positive energy output, but you get the reaction itself - we directly observe this reaction and the particles and everything that goes into it.

For a long time trudnopisaka asked me to make a post about the thermonuclear reactor under construction. Find out interesting details of the technology, find out why this project is taking so long to be implemented. I've finally collected the material. Let's get acquainted with the details of the project.

How did it all start? The “energy challenge” arose as a result of a combination of the following three factors:

1. Humanity now consumes a huge amount of energy.

Currently, the world's energy consumption is about 15.7 terawatts (TW). Dividing this value by the world population, we get approximately 2400 watts per person, which can be easily estimated and visualized. The energy consumed by every inhabitant of the Earth (including children) corresponds to the round-the-clock operation of 24 hundred-watt electric lamps. However, the consumption of this energy across the planet is very uneven, as it is very large in several countries and negligible in others. Consumption (calculated per person) is 10.3 kW in the USA (one of the record values), 6.3 kW in Russian Federation, 5.1 kW in the UK, etc., but on the other hand it is only 0.21 kW in Bangladesh (only 2% of US energy consumption!).

2. World energy consumption is increasing dramatically.

According to the forecast of the International Energy Agency (2006), global energy consumption should increase by 50% by 2030. Developed countries could, of course, do just fine without additional energy, but this growth is necessary to lift people out of poverty in developing countries, where 1.5 billion people suffer from severe power shortages.

3. Currently, 80% of the world's energy comes from burning fossil fuels(oil, coal and gas), the use of which:
a) potentially poses a risk of catastrophic environmental changes;
b) inevitably must end someday.

From what has been said, it is clear that now we must prepare for the end of the era of using fossil fuels

Currently, nuclear power plants produce energy released during fission reactions of atomic nuclei on a large scale. The creation and development of such stations should be encouraged in every possible way, but it must be taken into account that the reserves of one of the most important materials for their operation (cheap uranium) can also be completely used up within the next 50 years. The possibilities of nuclear fission-based energy can (and should) be significantly expanded through the use of more efficient energy cycles, allowing the amount of energy produced to almost double. To develop energy in this direction, it is necessary to create thorium reactors (the so-called thorium breeder reactors or breeder reactors), in which the reaction produces more thorium than the original uranium, as a result of which the total amount of energy produced for a given amount of substance increases by 40 times . It also seems promising to create plutonium breeders using fast neutrons, which are much more efficient than uranium reactors and can produce 60 times more energy. It may be that to develop these areas it will be necessary to develop new, non-standard methods for obtaining uranium (for example, from sea ​​water, which seems to be the most accessible).

Fusion power plants

The figure shows a schematic diagram (not to scale) of the device and operating principle of a thermonuclear power plant. In the central part there is a toroidal (donut-shaped) chamber with a volume of ~2000 m3, filled with tritium-deuterium (T-D) plasma heated to a temperature above 100 M°C. The neutrons produced during the fusion reaction (1) leave the “magnetic bottle” and enter the shell shown in the figure with a thickness of about 1 m.

Inside the shell, neutrons collide with lithium atoms, resulting in a reaction that produces tritium:

neutron + lithium → helium + tritium

In addition, competing reactions occur in the system (without the formation of tritium), as well as many reactions with the release of additional neutrons, which then also lead to the formation of tritium (in this case, the release of additional neutrons can be significantly enhanced, for example, by introducing beryllium atoms into the shell and lead). The overall conclusion is that this facility could (at least theoretically) undergo a nuclear fusion reaction that would produce tritium. In this case, the amount of tritium produced should not only meet the needs of the installation itself, but also be even somewhat larger, which will make it possible to supply new installations with tritium. It is this operating concept that must be tested and implemented in the ITER reactor described below.

In addition, neutrons must heat the shell in so-called pilot plants (in which relatively “ordinary” construction materials will be used) to approximately 400°C. In the future, it is planned to create improved installations with a shell heating temperature above 1000°C, which can be achieved through the use of the latest high-strength materials (such as silicon carbide composites). The heat generated in the shell, as in conventional stations, is taken by the primary cooling circuit with a coolant (containing, for example, water or helium) and transferred to the secondary circuit, where water steam is produced and supplied to the turbines.

1985 - The Soviet Union proposed the next generation Tokamak plant, using the experience of four leading countries in creating fusion reactors. The United States of America, together with Japan and the European Community, put forward a proposal for the implementation of the project.

Currently, in France, construction is underway on the international experimental thermonuclear reactor ITER (International Tokamak Experimental Reactor), described below, which will be the first tokamak capable of “igniting” plasma.

The most advanced existing tokamak installations have long reached temperatures of about 150 M°C, close to the values ​​​​required for the operation of a fusion station, but the ITER reactor should be the first large-scale power plant designed for long-term operation. In the future, it will be necessary to significantly improve its operating parameters, which will require, first of all, increasing the pressure in the plasma, since the rate of nuclear fusion at a given temperature is proportional to the square of the pressure. The main scientific problem in this case is related to the fact that when the pressure in the plasma increases, very complex and dangerous instabilities arise, that is, unstable operating modes.

Why do we need this?

The main advantage of nuclear fusion is that it requires only very small amounts of substances that are very common in nature as fuel. The nuclear fusion reaction in the described installations can lead to the release of enormous amounts of energy, ten million times higher than the standard heat released during conventional chemical reactions (such as the combustion of fossil fuels). For comparison, we point out that the amount of coal required to power a thermal power plant with a capacity of 1 gigawatt (GW) is 10,000 tons per day (ten railway cars), and a fusion plant of the same power will consume only about 1 kilogram of the D+T mixture per day .

Deuterium is a stable isotope of hydrogen; In about one out of every 3,350 molecules of ordinary water, one of the hydrogen atoms is replaced by deuterium (a legacy from the Big Bang). This fact makes it easy to organize a fairly cheap production of the required amount of deuterium from water. It is more difficult to obtain tritium, which is unstable (half-life is about 12 years, as a result of which its content in nature is negligible), however, as shown above, tritium will appear directly inside the thermonuclear installation during operation, due to the reaction of neutrons with lithium.

Thus, the initial fuel for a fusion reactor is lithium and water. Lithium is a common metal widely used in household appliances (batteries for mobile phones and so on.). The installation described above, even taking into account non-ideal efficiency, will be able to produce 200,000 kWh of electrical energy, which is equivalent to the energy contained in 70 tons of coal. The amount of lithium required for this is contained in one computer battery, and the amount of deuterium is in 45 liters of water. The above value corresponds to the current electricity consumption (calculated per person) in the EU countries over 30 years. The very fact that such an insignificant amount of lithium can ensure the generation of such an amount of electricity (without CO2 emissions and without the slightest air pollution) is a fairly serious argument for the fastest and most vigorous development of thermonuclear energy (despite all the difficulties and problems) and even without one hundred percent confidence in the success of such research.

Deuterium should last for millions of years, and reserves of easily mined lithium are sufficient to supply needs for hundreds of years. Even if lithium in rocks runs out, we can extract it from water, where it is found in concentrations high enough (100 times the concentration of uranium) to make its extraction economically feasible.

An experimental thermonuclear reactor (International thermonuclear experimental reactor) is being built near the city of Cadarache in France. The main goal of the ITER project is to implement a controlled thermonuclear fusion reaction on an industrial scale.

Per unit weight of thermonuclear fuel, about 10 million times more energy is obtained than when burning the same amount of organic fuel, and about a hundred times more than when splitting uranium nuclei in the reactors of currently operating nuclear power plants. If the calculations of scientists and designers come true, this will give humanity an inexhaustible source of energy.

Therefore, a number of countries (Russia, India, China, Korea, Kazakhstan, USA, Canada, Japan, European Union countries) joined forces in creating the International Thermonuclear Research Reactor - a prototype of new power plants.

ITER is a facility that creates conditions for the synthesis of hydrogen and tritium atoms (an isotope of hydrogen), resulting in the formation of a new atom - a helium atom. This process is accompanied by a huge burst of energy: the temperature of the plasma in which the thermonuclear reaction occurs is about 150 million degrees Celsius (for comparison, the temperature of the Sun’s core is 40 million degrees). In this case, the isotopes burn out, leaving virtually no radioactive waste.
The scheme of participation in the international project provides for the supply of reactor components and financing of its construction. In exchange for this, each of the participating countries receives full access to all technologies for creating a thermonuclear reactor and to the results of all experimental work on this reactor, which will serve as the basis for the design of serial power thermonuclear reactors.

The reactor, based on the principle of thermonuclear fusion, has no radioactive radiation and is completely safe for the environment. It can be located almost anywhere in the world, and the fuel for it is ordinary water. Construction of ITER is expected to last about ten years, after which the reactor is expected to be in use for 20 years.

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Russia's interests in the Council of the International Organization for the Construction of the ITER Thermonuclear Reactor in the coming years will be represented by Corresponding Member of the Russian Academy of Sciences Mikhail Kovalchuk - Director of the Kurchatov Institute, Institute of Crystallography of the Russian Academy of Sciences and Scientific Secretary of the Presidential Council on Science, Technology and Education. Kovalchuk will temporarily replace academician Evgeniy Velikhov in this post, who was elected chairman of the ITER International Council for the next two years and does not have the right to combine this position with the duties of an official representative of a participating country.

The total cost of construction is estimated at 5 billion euros, and the same amount will be required for trial operation of the reactor. The shares of India, China, Korea, Russia, the USA and Japan each account for approximately 10 percent of the total value, 45 percent comes from the countries of the European Union. However, for now European states they did not agree on how exactly the costs would be distributed between them. Because of this, the start of construction was postponed to April 2010. Despite the latest delay, scientists and officials involved in ITER say they will be able to complete the project by 2018.

The estimated thermonuclear power of ITER is 500 megawatts. Individual magnet parts reach a weight of 200 to 450 tons. To cool ITER, 33 thousand cubic meters of water per day will be required.

In 1998, the United States stopped funding its participation in the project. After the Republicans came to power and rolling blackouts began in California, the Bush administration announced increased investment in energy. The United States did not intend to participate in the international project and was engaged in its own thermonuclear project. In early 2002, President Bush's technology adviser John Marburger III said that the United States had changed its mind and intended to return to the project.

In terms of the number of participants, the project is comparable to another major international scientific project - the International Space Station. The cost of ITER, which previously reached 8 billion dollars, then amounted to less than 4 billion. As a result of the withdrawal of the United States from participation, it was decided to reduce the reactor power from 1.5 GW to 500 MW. Accordingly, the price of the project has also decreased.

In June 2002, the symposium “ITER Days in Moscow” was held in the Russian capital. It discussed the theoretical, practical and organizational problems of reviving the project, the success of which can change the fate of humanity and give it a new type of energy, comparable in efficiency and economy only to the energy of the Sun.

In July 2010, representatives of the countries participating in the ITER international thermonuclear reactor project approved its budget and construction schedule at an extraordinary meeting held in Cadarache, France. .

At the last extraordinary meeting, project participants approved the start date for the first experiments with plasma - 2019. Full experiments are planned for March 2027, although the project management asked technical specialists to try to optimize the process and begin experiments in 2026. The meeting participants also decided on the costs of constructing the reactor, but the amounts planned to be spent on creating the installation were not disclosed. According to information received by the editor of the ScienceNOW portal from an unnamed source, by the time experiments begin, the cost of the ITER project could reach 16 billion euros.

The meeting in Cadarache also marked the first official working day for the new project director, Japanese physicist Osamu Motojima. Before him, the project had been led since 2005 by the Japanese Kaname Ikeda, who wished to leave his post immediately after the budget and construction deadlines were approved.

Fusion reactor ITER is a joint project of the European Union, Switzerland, Japan, USA, Russia, South Korea, China and India. The idea of ​​creating ITER has been under consideration since the 80s of the last century, however, due to financial and technical difficulties, the cost of the project is constantly growing, and the construction start date is constantly being postponed. In 2009, experts expected that work on creating the reactor would begin in 2010. Later, this date was moved, and first 2018 and then 2019 were named as the launch time of the reactor.

Thermonuclear fusion reactions are reactions of fusion of nuclei of light isotopes to form a heavier nucleus, which are accompanied by a huge release of energy. In theory, fusion reactors can produce a lot of energy at low cost, but at the moment scientists spend much more energy and money to start and maintain the fusion reaction.

Fusion is cheap and environmentally friendly safe way energy production. Uncontrolled thermonuclear fusion has been occurring on the Sun for billions of years - helium is formed from the heavy hydrogen isotope deuterium. This releases a colossal amount of energy. However, people on Earth have not yet learned to control such reactions.

The ITER reactor will use hydrogen isotopes as fuel. During a thermonuclear reaction, energy is released when light atoms combine into heavier ones. To achieve this, the gas must be heated to a temperature of over 100 million degrees - much higher than the temperature at the center of the Sun. Gas at this temperature turns into plasma. At the same time, atoms of hydrogen isotopes merge, turning into helium atoms with the release of a large number of neutrons. A power plant operating on this principle will use the energy of neutrons slowed down by a layer of dense material (lithium).

Why did the creation of thermonuclear installations take so long?

Why have such important and valuable installations, the benefits of which have been discussed for almost half a century, not yet been created? There are three main reasons (discussed below), the first of which can be called external or social, and the other two - internal, that is, determined by the laws and conditions of the development of thermonuclear energy itself.

1. For a long time, it was believed that the problem of the practical use of thermonuclear fusion energy did not require urgent decisions and actions, since back in the 80s of the last century, fossil fuel sources seemed inexhaustible, and environmental problems and climate change did not concern the public. In 1976, the Fusion Energy Advisory Committee at the US Department of Energy attempted to estimate the time frame for R&D and a demonstration fusion power plant at different options research funding. At the same time, it was discovered that the volume of annual funding for research in this direction is completely insufficient, and if the existing level of appropriations is maintained, the creation of thermonuclear installations will never be successful, since the allocated funds do not correspond even to the minimum, critical level.

2. A more serious obstacle to the development of research in this area is that a thermonuclear installation of the type under discussion cannot be created and demonstrated on a small scale. From the explanations presented below, it will become clear that thermonuclear fusion requires not only magnetic confinement of the plasma, but also sufficient heating of it. The ratio of expended and received energy increases at least in proportion to the square of the linear dimensions of the installation, as a result of which the scientific and technical capabilities and advantages of thermonuclear installations can be tested and demonstrated only at fairly large stations, such as the mentioned ITER reactor. Society was simply not ready to finance such large projects until there was sufficient confidence in success.

3. The development of thermonuclear energy was very complex, however (despite insufficient funding and difficulties in choosing centers for creating the JET and ITER installations) last years There is clear progress, although a functioning station has not yet been created.

The modern world is facing a very serious energy challenge, which can more accurately be called an “uncertain energy crisis.” The problem is related to the fact that reserves of fossil fuels may run out in the second half of this century. Moreover, burning fossil fuels may result in the need to somehow sequester and “store” the carbon dioxide released into the atmosphere (the CCS program mentioned above) to prevent major changes in the planet’s climate.

Currently, almost all the energy consumed by humanity is created by burning fossil fuels, and the solution to the problem may be associated with the use of solar energy or nuclear energy (the creation of fast neutron breeder reactors, etc.). The global problem caused by the growing population of developing countries and their need to improve living standards and increase the amount of energy produced cannot be solved on the basis of these approaches alone, although, of course, any attempts to develop alternative methods of energy production should be encouraged.

Strictly speaking, we have a small choice of behavioral strategies and the development of thermonuclear energy is extremely important, even despite the lack of a guarantee of success. The Financial Times newspaper (dated January 25, 2004) wrote about this:

Let's hope that there will be no major and unexpected surprises on the path to the development of thermonuclear energy. In this case, in about 30 years we will be able to supply electric current from it to energy networks for the first time, and in just over 10 years the first commercial fusion power plant. It is possible that in the second half of this century, nuclear fusion energy will begin to replace fossil fuels and gradually begin to play an increasingly important role in providing energy to humanity on a global scale.

There is no absolute guarantee that the task of creating thermonuclear energy (as an effective and large-scale source of energy for all humanity) will be completed successfully, but the likelihood of success in this direction is quite high. Considering the enormous potential of thermonuclear stations, all costs for projects for their rapid (and even accelerated) development can be considered justified, especially since these investments look very modest against the backdrop of the monstrous global energy market ($4 trillion per year8). Meeting humanity's energy needs is a very serious problem. As fossil fuels become less available (and their use becomes undesirable), the situation is changing, and we simply cannot afford not to develop fusion energy.

To the question “When will thermonuclear energy appear?” Lev Artsimovich (a recognized pioneer and leader of research in this field) once responded that “it will be created when it becomes truly necessary for humanity”

ITER will be the first fusion reactor to produce more energy than it consumes. Scientists measure this characteristic using a simple coefficient they call "Q." If ITER achieves all its scientific goals, it will produce 10 times more energy than it consumes. The last device built, the Joint European Torus in England, is a smaller prototype fusion reactor that, in its final stages of scientific research, achieved a Q value of almost 1. This means that it produced exactly the same amount of energy as it consumed. ITER will go beyond this by demonstrating energy creation from fusion and achieving a Q value of 10. The idea is to generate 500 MW from an energy consumption of approximately 50 MW. Thus, one of the scientific goals of ITER is to prove that a Q value of 10 can be achieved.

Another scientific goal is that ITER will have a very long "burn" time - a pulse of extended duration up to one hour. ITER is a research experimental reactor that cannot produce energy continuously. When ITER starts operating, it will be on for one hour, after which it will need to be turned off. This is important because until now the standard devices we have created have been capable of having a burning time of several seconds or even tenths of a second - this is the maximum. The "Joint European Torus" reached its Q value of 1 with a burn time of approximately two seconds with a pulse length of 20 seconds. But a process that lasts a few seconds is not truly permanent. By analogy with starting a car engine: briefly turning on the engine and then turning it off is not yet real operation of the car. Only when you drive your car for half an hour will it reach a constant operating mode and demonstrate that such a car can actually be driven.

That is, from technical and scientific points In view, ITER will provide a Q value of 10 and an increased burn time.

The thermonuclear fusion program is truly international and broad in nature. People are already counting on the success of ITER and are thinking about the next step - creating a prototype of an industrial thermonuclear reactor called DEMO. To build it, ITER needs to work. We must achieve our scientific goals because this will mean that the ideas we put forward are entirely feasible. However, I agree that you should always think about what comes next. In addition, as ITER operates for 25-30 years, our knowledge will gradually deepen and expand, and we will be able to more accurately outline our next step.

Indeed, there is no debate about whether ITER should be a tokamak. Some scientists pose the question quite differently: should ITER exist? Specialists in different countries ah, developing their own, not so large-scale thermonuclear projects, claim that such a large reactor is not needed at all.

However, their opinion should hardly be considered authoritative. Physicists who have been working with toroidal traps for several decades were involved in the creation of ITER. The design of the experimental thermonuclear reactor in Karadash was based on all the knowledge gained during experiments on dozens of predecessor tokamaks. And these results indicate that the reactor must be a tokamak, and a large one at that.

JET At the moment, the most successful tokamak can be considered JET, built by the EU in the British town of Abingdon. This is the largest tokamak-type reactor created to date, the large radius of the plasma torus is 2.96 meters. The power of the thermonuclear reaction has already reached more than 20 megawatts with a retention time of up to 10 seconds. The reactor returns about 40% of the energy put into the plasma.

It is the physics of plasma that determines the energy balance,” Igor Semenov told Infox.ru. What is energy balance, MIPT associate professor described at simple example: “We all saw the fire burning. In fact, it is not wood that burns there, but gas. The energy chain there is like this: the gas burns, the wood heats, the wood evaporates, the gas burns again. Therefore, if we throw water on a fire, we will abruptly take energy from the system for the phase transition of liquid water into a vapor state. The balance will become negative and the fire will go out. There is another way - we can simply take the firebrands and spread them in space. The fire will also go out. It’s the same in the thermonuclear reactor we are building. The dimensions are chosen to create an appropriate positive energy balance for this reactor. Sufficient to build a real nuclear power plant in the future, solving at this experimental stage all the problems that currently remain unresolved.”

The dimensions of the reactor were changed once. This happened at the turn of the 20th-21st centuries, when the United States withdrew from the project, and the remaining members realized that the ITER budget (by that time it was estimated at 10 billion US dollars) was too large. Physicists and engineers were required to reduce the cost of installation. And this could only be done due to size. The “redesign” of ITER was led by the French physicist Robert Aymar, who previously worked on the French Tore Supra tokamak in Karadash. The outer radius of the plasma torus has been reduced from 8.2 to 6.3 meters. However, the risks associated with the reduction in size were partly compensated for by several additional superconducting magnets, which made it possible to implement the plasma confinement mode, which was open and studied at that time.

source
http://ehorussia.com
http://oko-planet.su

Is thermonuclear energy necessary?

On at this stage development of civilization, we can safely say that humanity faces an “energy challenge.” It is due to several fundamental factors:

— Humanity now consumes a huge amount of energy.

Currently, the world's energy consumption is about 15.7 terawatts (TW). Dividing this value by the population of the planet, we get approximately 2400 watts per person, which can be easily estimated and imagined. The energy consumed by every inhabitant of the Earth (including children) corresponds to the round-the-clock operation of 24 100-watt electric lamps.

— World energy consumption is increasing rapidly.

According to the International Energy Agency (2006), global energy consumption is expected to increase by 50% by 2030.

— Currently, 80% of the energy consumed by the world is created by burning fossil fuels (oil, coal and gas), the use of which potentially poses the risk of catastrophic environmental changes.

The following joke is popular among Saudi Arabians: “My father rode a camel. I got a car, and my son is already flying a plane. But now his son will ride a camel again.”

This appears to be the case, as all serious forecasts are that the world's oil reserves will largely run out in about 50 years.

Even based on estimates from the US Geological Survey (this forecast is much more optimistic than others), the growth of world oil production will continue for no more than the next 20 years (other experts predict that peak production will be reached in 5-10 years), after which the volume of oil produced will begin decreasing at a rate of about 3% per year. Prospects for natural gas production don't look much better. It is usually said that we will have enough coal for another 200 years, but this forecast is based on maintaining the existing level of production and consumption. Meanwhile, coal consumption is now increasing by 4.5% per year, which immediately reduces the mentioned period of 200 years to just 50 years.

Thus, we should now prepare for the end of the era of using fossil fuels.

Unfortunately, currently existing alternative energy sources are not able to cover the growing needs of humanity. According to the most optimistic estimates, the maximum amount of energy (in specified thermal equivalent) generated by the listed sources is only 3 TW (wind), 1 TW (hydro), 1 TW (biological sources) and 100 GW (geothermal and marine plants). The total amount of additional energy (even in this most optimal forecast) is only about 6 TW. It is worth noting that the development of new energy sources is a very complex technical task, so the cost of the energy they produce will in any case be higher than with the usual combustion of coal, etc. It seems quite obvious that

humanity must look for some other sources of energy, for which currently only the Sun and thermonuclear fusion reactions can really be considered.

The sun is potentially an almost inexhaustible source of energy. The amount of energy hitting just 0.1% of the planet's surface is equivalent to 3.8 TW (even if converted with only 15% efficiency). The problem lies in our inability to capture and convert this energy, which is associated both with the high cost of solar panels and with the problems of accumulation, storage and further transmission of the resulting energy to the required regions.

Currently, nuclear power plants produce energy released during fission reactions of atomic nuclei on a large scale. I believe that the creation and development of such stations should be encouraged in every possible way, but it must be taken into account that the reserves of one of the most important materials for their operation (cheap uranium) can also be completely used up within the next 50 years.

Another important direction of development is the use of nuclear fusion (nuclear fusion), which now acts as the main hope for salvation, although the time of creation of the first thermonuclear power plants remains uncertain. This lecture is dedicated to this topic.

What is nuclear fusion?

Nuclear fusion, which is the basis for the existence of the Sun and stars, potentially represents an inexhaustible source of energy for the development of the Universe in general. Experiments carried out in Russia (Russia is the birthplace of the Tokamak thermonuclear plant), the USA, Japan, Germany, as well as in the UK as part of the Joint European Torus (JET) program, which is one of the leading research programs in the world, show that nuclear fusion can provide not only the current energy needs of humanity (16 TW), but also a much larger amount of energy.

Nuclear fusion energy is very real, and the main question is whether we can create sufficiently reliable and cost-effective fusion plants.

Nuclear fusion processes are reactions involving the fusion of light atomic nuclei into heavier ones, releasing a certain amount of energy.

First of all, among them it should be noted the reaction between two isotopes (deuterium and tritium) of hydrogen, which is very common on Earth, as a result of which helium is formed and a neutron is released. The reaction can be written as follows:

D + T = 4 He + n + energy (17.6 MeV).

The released energy, resulting from the fact that helium-4 has very strong nuclear bonds, is converted into ordinary kinetic energy, distributed between the neutron and the helium-4 nucleus in the proportion 14.1 MeV/3.5 MeV.

To initiate (ignite) the fusion reaction, it is necessary to completely ionize and heat the gas from a mixture of deuterium and tritium to a temperature above 100 million degrees Celsius (we will denote it by M degrees), which is about five times higher than the temperature at the center of the Sun. Already at temperatures of several thousand degrees, interatomic collisions lead to electrons being knocked out of atoms, resulting in the formation of a mixture of separated nuclei and electrons known as plasma, in which positively charged and highly energetic deuterons and tritons (that is, deuterium and tritium nuclei) experience strong mutual repulsion. However, the high temperature of the plasma (and the associated high ion energy) allows these deuterium and tritium ions to overcome Coulomb repulsion and collide with each other. At temperatures above 100 M degrees, the most “energetic” deuterons and tritons come together in collisions at such close distances that powerful nuclear forces begin to act between them, forcing them to merge with each other into a single whole.

Carrying out this process in the laboratory involves three very complex problems. First of all, the gas mixture of nuclei D and T must be heated to temperatures above 100 M degrees, somehow preventing it from cooling and becoming contaminated (due to reactions with the walls of the vessel).

To solve this problem, “magnetic traps” were invented, called Tokamak, which prevent the interaction of plasma with the walls of the reactor.

In the described method, the plasma is heated by an electric current flowing inside the torus to approximately 3 M degrees, which, however, is still insufficient to initiate the reaction. To additionally heat the plasma, energy is either “pumped” into it with radio frequency radiation (as in a microwave oven), or beams of high-energy neutral particles are injected, which transfer their energy to the plasma during collisions. In addition, the release of heat occurs due to thermonuclear reactions themselves (as will be discussed below), as a result of which the “ignition” of the plasma should occur in a sufficiently large installation.

Currently, in France, construction is beginning on the international experimental thermonuclear reactor ITER (International Thermonuclear Experimental Reactor), described below, which will be the first Tokamak capable of “igniting” plasma.

In the most advanced existing Tokamak-type installations, temperatures of about 150 M degrees have long been achieved, close to the values ​​​​required for the operation of a thermonuclear station, but the ITER reactor should become the first large-scale power plant designed for long-term operation. In the future, it will be necessary to significantly improve the parameters of its operation, which will require, first of all, an increase in the pressure in the plasma, since the rate of nuclear fusion at a given temperature is proportional to the square of the pressure.

The main scientific problem in this case is related to the fact that when the pressure in the plasma increases, very complex and dangerous instabilities arise, that is, unstable operating modes.

The electrically charged helium nuclei that arise during the fusion reaction are held inside a “magnetic trap”, where they are gradually slowed down due to collisions with other particles, and the energy released during collisions helps maintain high temperature plasma cord. Neutral (having no electrical charge) neutrons leave the system and transfer their energy to the walls of the reactor, and the heat taken from the walls is the source of energy for the operation of turbines that generate electricity. The problems and difficulties of operating such a facility are associated, first of all, with the fact that a powerful flow of high-energy neutrons and the released energy (in the form of electromagnetic radiation and plasma particles) seriously affect the reactor and can destroy the materials from which it is made.

Because of this, the design of thermonuclear installations is very complex. Physicists and engineers are faced with the task of ensuring high reliability of their work. The design and construction of thermonuclear stations require them to solve a number of diverse and very complex technological problems.

Thermonuclear power plant design

The figure shows a schematic diagram (not to scale) of the device and operating principle of a thermonuclear power plant. In the central part there is a toroidal (donut-shaped) chamber with a volume of ~ 2000 m 3, filled with tritium-deuterium (T-D) plasma heated to a temperature above 100 M degrees. The neutrons produced during the fusion reaction leave the “magnetic trap” and enter the shell shown in the figure with a thickness of about 1 m. 1

Inside the shell, neutrons collide with lithium atoms, resulting in a reaction that produces tritium:

neutron + lithium = helium + tritium.

In addition, competing reactions occur in the system (without the formation of tritium), as well as many reactions with the release of additional neutrons, which then also lead to the formation of tritium (in this case, the release of additional neutrons can be significantly enhanced, for example, by introducing atoms into the shell beryllium and lead). The overall conclusion is that this facility could (at least theoretically) undergo a nuclear fusion reaction that would produce tritium. In this case, the amount of tritium produced should not only meet the needs of the installation itself, but also be even somewhat larger, which will make it possible to supply new installations with tritium.

It is this operating concept that must be tested and implemented in the ITER reactor described below.

Neutrons should heat the shell in so-called pilot plants (in which relatively “ordinary” construction materials will be used) to a temperature of approximately 400 degrees. In the future, it is planned to create improved installations with a shell heating temperature above 1000 degrees, which can be achieved through the use of the latest high-strength materials (such as silicon carbide composites). The heat generated in the shell, as in conventional stations, is taken by the primary cooling circuit with a coolant (containing, for example, water or helium) and transferred to the secondary circuit, where water steam is produced and supplied to the turbines.

The main advantage of nuclear fusion is that it requires only very small amounts of substances that are very common in nature as fuel.

The nuclear fusion reaction in the described installations can lead to the release of enormous amounts of energy, ten million times higher than the standard heat released during conventional chemical reactions (such as the combustion of fossil fuels). For comparison, we point out that the amount of coal required to power a thermal power plant with a capacity of 1 gigawatt (GW) is 10,000 tons per day (ten railway cars), and a fusion plant of the same power will consume only about 1 kg of D+ mixture per day T.

Deuterium is a stable isotope of hydrogen; In about one out of every 3,350 molecules of ordinary water, one of the hydrogen atoms is replaced by deuterium (a legacy from the Big Bang of the Universe). This fact makes it easy to organize a fairly cheap production of the required amount of deuterium from water. It is more difficult to obtain tritium, which is unstable (half-life is about 12 years, as a result of which its content in nature is negligible), however, as shown above, tritium will be produced directly inside the thermonuclear installation during operation due to the reaction of neutrons with lithium.

Thus, the initial fuel for a fusion reactor is lithium and water.

Lithium is a common metal widely used in household appliances (cell phone batteries, for example). The installation described above, even taking into account non-ideal efficiency, will be able to produce 200,000 kWh of electrical energy, which is equivalent to the energy contained in 70 tons of coal. The amount of lithium required for this is contained in one computer battery, and the amount of deuterium is in 45 liters of water. The above value corresponds to the current electricity consumption (calculated per person) in the EU countries over 30 years. The very fact that such an insignificant amount of lithium can provide the generation of such an amount of electricity (without CO 2 emissions and without the slightest air pollution) is a fairly serious argument for the rapid and vigorous development of research on the development of thermonuclear energy (despite all the difficulties and problems) even with long-term prospect of creating a cost-effective thermonuclear reactor.

Deuterium should last for millions of years, and reserves of easily mined lithium are quite sufficient to supply needs for hundreds of years.

Even if lithium in rocks runs out, we can extract it from water, where it is found in concentrations high enough (100 times the concentration of uranium) to make its extraction economically feasible.

Fusion energy not only promises humanity, in principle, the possibility of producing huge amounts of energy in the future (without CO 2 emissions and without air pollution), but also has a number of other advantages.

1 ) High internal security.

The plasma used in thermonuclear installations has a very low density (about a million times lower than the density of the atmosphere), as a result of which the operating environment of the installations will never contain enough energy to cause serious incidents or accidents.

In addition, loading with “fuel” must be carried out continuously, which makes it easy to stop its operation, not to mention the fact that in the event of an accident and a sharp change in environmental conditions, the thermonuclear “flame” should simply go out.

What are the dangers associated with thermonuclear energy? First, it is worth noting that although the fusion products (helium and neutrons) are not radioactive, the reactor shell can become radioactive under prolonged neutron irradiation.

Secondly, tritium is radioactive and has a relatively short half-life (12 years). But although the volume of plasma used is significant, due to its low density it contains only a very small amount of tritium (a total weight of about ten postage stamps). That's why

even in the most severe situations and accidents (complete destruction of the shell and the release of all the tritium contained in it, for example, during an earthquake and an airplane crash into the station) in environment Only a small amount of fuel will arrive, which will not require the evacuation of the population from nearby settlements.

2 ) Energy cost.

It is expected that the so-called “internal” price of electricity received (the cost of production itself) will become acceptable if it is 75% of the price already existing on the market. “Affordable” in this case means that the price will be lower than the price of energy produced using old hydrocarbon fuels. The “external” cost (side effects, impacts on public health, climate, ecology, etc.) will be essentially zero.

International experimental thermonuclear reactor ITER

The main next step is to build the ITER reactor, designed to demonstrate the very possibility of igniting a plasma and, on this basis, obtaining at least a tenfold gain in energy (relative to the energy spent on heating the plasma). The ITER reactor will be an experimental device that will not even be equipped with turbines for generating electricity and devices for using it. The purpose of its creation is to study the conditions that must be met during the operation of such power plants, as well as the creation on this basis of real, economically viable power plants, which, apparently, should exceed ITER in size. Creating real prototypes of fusion power plants (that is, plants fully equipped with turbines, etc.) requires solving the following two problems. First, it is necessary to continue to develop new materials (capable of withstanding the very harsh operating conditions described) and test them in accordance with the special rules for the IFMIF (International Fusion Irradiation Facility) equipment described below. Secondly, many purely technical problems need to be solved and new technologies need to be developed related to remote control, heating, cladding design, fuel cycles, etc. 2

The figure shows the ITER reactor, which is superior to today's largest JET installation not only in all linear dimensions (about twice), but also in the magnitude of the magnetic fields used in it and the currents flowing through the plasma.

The purpose of creating this reactor is to demonstrate the capabilities of the combined efforts of physicists and engineers in constructing a large-scale fusion power plant.

The installation capacity planned by the designers is 500 MW (with energy consumption at the system input of only about 50 MW). 3

The ITER installation is being created by a consortium that includes the EU, China, India, Japan, South Korea, Russia and the USA. The total population of these countries is about half of the total population of the Earth, so the project can be called a global response to a global challenge. The main components and components of the ITER reactor have already been created and tested, and construction has already begun in Cadarache (France). The launch of the reactor is planned for 2020, and the production of deuterium-tritium plasma is planned for 2027, since commissioning of the reactor requires long and serious tests for plasma from deuterium and tritium.

The ITER reactor's magnetic coils are based on superconducting materials (which, in principle, allow continuous operation as long as current is maintained in the plasma), so the designers hope to provide a guaranteed duty cycle of at least 10 minutes. It is clear that the presence of superconducting magnetic coils is fundamentally important for the continuous operation of a real thermonuclear power plant. Superconducting coils have already been used in Tokamak-type devices, but they have not previously been used in such large-scale installations designed for tritium plasma. In addition, the ITER facility will be the first to use and test different shell modules designed to operate in real stations where tritium nuclei can be generated or “recovered.”

The main goal of constructing the installation is to demonstrate successful control of plasma combustion and the possibility of actually obtaining energy in thermonuclear devices at the existing level of technology development.

Further development in this direction, of course, will require a lot of effort to improve the efficiency of the devices, especially from the point of view of their economic feasibility, which is associated with serious and lengthy research, both at the ITER reactor and on other devices. Among the assigned tasks, the following three should be particularly highlighted:

1) It is necessary to show that the existing level of science and technology already makes it possible to obtain a 10-fold gain in energy (compared to that expended to maintain the process) in a controlled nuclear fusion process. The reaction must proceed without the occurrence of dangerous unstable conditions, without overheating and damage to structural materials, and without contamination of the plasma with impurities. With fusion energy powers of the order of 50% of the plasma heating power, these goals have already been achieved in experiments in small facilities, but the creation of the ITER reactor will test the reliability of control methods in a much larger facility that produces much more energy over a long time. The ITER reactor is designed to test and agree on the requirements for a future fusion reactor, and its construction is a very complex and interesting task.

2) It is necessary to study methods for increasing the pressure in the plasma (recall that the reaction rate at a given temperature is proportional to the square of the pressure) to prevent the occurrence of dangerous unstable modes of plasma behavior. The success of research in this direction will either ensure the operation of the reactor at a higher plasma density, or lower the requirements for the strength of the generated magnetic fields, which will significantly reduce the cost of the electricity produced by the reactor.

3) Tests must confirm that continuous operation of the reactor in a stable mode can be realistically ensured (from an economic and technical point of view, this requirement seems very important, if not the main one), and the installation can be started without huge expenditures of energy. Researchers and designers really hope that the “continuous” flow of electromagnetic current through the plasma can be ensured by its generation in the plasma (due to high-frequency radiation and the injection of fast atoms).

The modern world is facing a very serious energy challenge, which can more accurately be called an “uncertain energy crisis.”

Currently, almost all the energy consumed by humanity is created by burning fossil fuels, and the solution to the problem may be associated with the use of solar energy or nuclear energy (the creation of fast neutron reactors, etc.). The global problem caused by the growing population of developing countries and their need to improve living standards and increase the amount of energy produced cannot be solved on the basis of these approaches alone, although, of course, any attempts to develop alternative methods of energy production should be encouraged.

If there are no major and unexpected surprises on the path to the development of thermonuclear energy, then subject to the developed reasonable and orderly program of action, which (of course, subject to good organization of work and sufficient funding) should lead to the creation of a prototype thermonuclear power plant. In this case, in about 30 years we will be able to supply electric current from it to energy networks for the first time, and in just over 10 years the first commercial thermonuclear power plant will begin to operate. It is possible that in the second half of this century, nuclear fusion energy will begin to replace fossil fuels and gradually begin to play an increasingly important role in providing energy to humanity on a global scale.

Without exaggeration, the international experimental thermonuclear reactor ITER can be called the most significant research project of our time. In terms of the scale of construction, it will easily outshine the Large Hadron Collider, and if successful, it will mark a much bigger step for all of humanity than a flight to the Moon. Indeed, potentially controlled thermonuclear fusion is an almost inexhaustible source of unprecedentedly cheap and clean energy.

This summer there were several good reasons to brush up on the technical details of the ITER project. Firstly, a grandiose undertaking, the official start of which is considered to be the meeting between Mikhail Gorbachev and Ronald Reagan back in 1985, is taking on material embodiment before our eyes. Designing a new generation reactor with the participation of Russia, the USA, Japan, China, India, South Korea and the European Union took more than 20 years. Today, ITER is no longer kilograms of technical documentation, but 42 hectares (1 km by 420 m) of a perfectly flat surface of one of the world's largest man-made platforms, located in the French city of Cadarache, 60 km north of Marseille. As well as the foundation of the future 360,000-ton reactor, consisting of 150,000 cubic meters of concrete, 16,000 tons of reinforcement and 493 columns with rubber-metal anti-seismic coating. And, of course, thousands of sophisticated scientific instruments and research facilities scattered across universities around the world.

March 2007. First photo of the future ITER platform from the air.

Production of key reactor components is well underway. In the spring, France reported the production of 70 frames for D-shaped toroidal field coils, and in June, winding of the first coils of superconducting cables, received from Russia from the Institute of Cable Industry in Podolsk, began.

The second good reason to remember ITER right now is political. The new generation reactor is a test not only for scientists, but also for diplomats. This is such an expensive and technically complex project that no country in the world can undertake it alone. From the ability of states to agree among themselves both scientifically and financial sector depends on whether the matter can be completed.

March 2009. 42 hectares of leveled site are awaiting the start of construction of a scientific complex.

The ITER Council was scheduled for June 18 in St. Petersburg, but the US State Department, as part of sanctions, banned American scientists from visiting Russia. Taking into account the fact that the very idea of ​​a tokamak (a toroidal chamber with magnetic coils, which is the basis of ITER) belongs to the Soviet physicist Oleg Lavrentiev, the project participants treated this decision as a curiosity and simply moved the meeting to Cadarache on the same date. These events once again reminded the whole world that Russia (along with South Korea) is most responsible for fulfilling its obligations to the ITER project.

February 2011. More than 500 holes were drilled in the seismic isolation shaft, all underground cavities were filled with concrete.

Scientists burn

The phrase “fusion reactor” makes many people wary. The associative chain is clear: a thermonuclear bomb is more terrible than just a nuclear one, which means that a thermonuclear reactor is more dangerous than Chernobyl.

In fact, nuclear fusion, on which the operating principle of the tokamak is based, is much safer and more efficient than nuclear fission used in modern nuclear power plants. Fusion is used by nature itself: the Sun is nothing more than a natural thermonuclear reactor.

The ASDEX tokamak, built in 1991 at Germany's Max Planck Institute, is used to test various reactor front wall materials, particularly tungsten and beryllium. The plasma volume in ASDEX is 13 m 3, almost 65 times less than in ITER.

The reaction involves nuclei of deuterium and tritium - isotopes of hydrogen. The deuterium nucleus consists of a proton and a neutron, and the tritium nucleus consists of a proton and two neutrons. Under normal conditions, equally charged nuclei repel each other, but at very high temperatures they can collide.

Upon collision, the strong interaction comes into play, which is responsible for combining protons and neutrons into nuclei. The nucleus of a new chemical element—helium—emerges. In this case, one free neutron is formed and a large amount of energy is released. The strong interaction energy in the helium nucleus is less than in the nuclei of the parent elements. Due to this, the resulting nucleus even loses mass (according to the theory of relativity, energy and mass are equivalent). Recalling the famous equation E = mc 2, where c is the speed of light, one can imagine the colossal energy potential nuclear fusion contains.

August 2011. The pouring of a monolithic reinforced concrete seismic isolating slab began.

To overcome the force of mutual repulsion, the initial nuclei must move very quickly, so temperature plays a key role in nuclear fusion. At the center of the Sun, the process occurs at a temperature of 15 million degrees Celsius, but it is facilitated by the colossal density of matter due to the action of gravity. The colossal mass of the star makes it an effective thermonuclear reactor.

It is not possible to create such a density on Earth. All we can do is increase the temperature. For hydrogen isotopes to release the energy of their nuclei to earthlings, a temperature of 150 million degrees is required, that is, ten times higher than on the Sun.

No one hard material in the Universe cannot come into direct contact with such a temperature. So just building a stove to cook helium won’t work. The same toroidal chamber with magnetic coils, or tokamak, helps solve the problem. The idea of ​​​​creating a tokamak dawned on the bright minds of scientists from different countries in the early 1950s, while the primacy is clearly attributed to the Soviet physicist Oleg Lavrentyev and his eminent colleagues Andrei Sakharov and Igor Tamm.

A vacuum chamber in the shape of a torus (a hollow donut) is surrounded by superconducting electromagnets, which create a toroidal magnetic field in it. It is this field that holds the plasma, hot up to ten times the sun, at a certain distance from the walls of the chamber. Together with the central electromagnet (inductor), the tokamak is a transformer. By changing the current in the inductor, they generate a current flow in the plasma - the movement of particles necessary for synthesis.

February 2012. 493 1.7-meter columns with seismic isolating pads made of rubber-metal sandwich were installed.

The Tokamak can rightfully be considered a model of technological elegance. The electric current flowing in the plasma creates a poloidal magnetic field that encircles the plasma cord and maintains its shape. Plasma exists under strictly defined conditions, and at the slightest change, the reaction immediately stops. Unlike a nuclear power plant reactor, a tokamak cannot “go wild” and increase the temperature uncontrollably.

In the unlikely event of destruction of the tokamak, there is no radioactive contamination. Unlike a nuclear power plant, a thermonuclear reactor does not produce radioactive waste, and the only product of the fusion reaction - helium - is not a greenhouse gas and is useful in the economy. Finally, the tokamak uses fuel very sparingly: during synthesis, only a few hundred grams of substance are contained in the vacuum chamber, and the estimated annual supply of fuel for an industrial power plant is only 250 kg.

April 2014. Construction of the cryostat building was completed, the walls of the 1.5-meter thick tokamak foundation were poured.

Why do we need ITER?

Tokamaks of the classical design described above were built in the USA and Europe, Russia and Kazakhstan, Japan and China. With their help, it was possible to prove the fundamental possibility of creating high-temperature plasma. However, building an industrial reactor capable of delivering more energy than it consumes is a task of a fundamentally different scale.

In a classic tokamak, the current flow in the plasma is created by changing the current in the inductor, and this process cannot be endless. Thus, the lifetime of the plasma is limited, and the reactor can only operate in pulsed mode. Ignition of plasma requires colossal energy - it’s no joke to heat anything to a temperature of 150,000,000 °C. This means that it is necessary to achieve a plasma lifetime that will produce energy that pays for ignition.

The fusion reactor is an elegant technical concept with minimal negative side effects. The flow of current in the plasma spontaneously forms a poloidal magnetic field that maintains the shape of the plasma filament, and the resulting high-energy neutrons combine with lithium to produce precious tritium.

For example, in 2009, during an experiment on the Chinese tokamak EAST (part of the ITER project), it was possible to maintain plasma at a temperature of 10 7 K for 400 seconds and 10 8 K for 60 seconds.

To hold the plasma longer, additional heaters of several types are needed. All of them will be tested at ITER. The first method - injection of neutral deuterium atoms - assumes that the atoms will enter the plasma pre-accelerated to a kinetic energy of 1 MeV using an additional accelerator.

This process is initially contradictory: only charged particles can be accelerated (they are affected by an electromagnetic field), and only neutral ones can be introduced into the plasma (otherwise they will affect the flow of current inside the plasma cord). Therefore, an electron is first removed from deuterium atoms, and positively charged ions enter the accelerator. The particles then enter the neutralizer, where they are reduced to neutral atoms by interacting with the ionized gas and introduced into the plasma. The ITER megavoltage injector is currently being developed in Padua, Italy.

The second heating method has something in common with heating food in the microwave. It involves exposing the plasma to electromagnetic radiation with a frequency corresponding to the speed of particle movement (cyclotron frequency). For positive ions this frequency is 40−50 MHz, and for electrons it is 170 GHz. To create powerful radiation of such a high frequency, a device called a gyrotron is used. Nine of the 24 ITER gyrotrons are manufactured at the Gycom facility in Nizhny Novgorod.

The classical concept of a tokamak assumes that the shape of the plasma filament is supported by a poloidal magnetic field, which is itself formed when current flows in the plasma. This approach is not applicable for long-term plasma confinement. The ITER tokamak has special poloidal field coils, the purpose of which is to keep the hot plasma away from the walls of the reactor. These coils are among the most massive and complex structural elements.

In order to be able to actively control the shape of the plasma, promptly eliminating vibrations at the edges of the cord, the developers provided small, low-power electromagnetic circuits located directly in the vacuum chamber, under the casing.

Fusion fuel infrastructure is a separate interesting topic. Deuterium is found in almost any water, and its reserves can be considered unlimited. But the world's reserves of tritium amount to tens of kilograms. 1 kg of tritium costs about $30 million. For the first launches of ITER, 3 kg of tritium will be needed. By comparison, about 2 kg of tritium per year is needed to maintain the nuclear capabilities of the United States Army.

However, in the future, the reactor will provide itself with tritium. The main fusion reaction produces high-energy neutrons that are capable of converting lithium nuclei into tritium. The development and testing of the first lithium reactor wall is one of ITER's most important goals. The first tests will use beryllium-copper cladding, the purpose of which is to protect the reactor mechanisms from heat. According to calculations, even if we transfer the entire energy sector of the planet to tokamaks, the world's lithium reserves will be enough for a thousand years of operation.

Preparing the 104-kilometer ITER Path cost France 110 million euros and four years of work. The road from the port of Fos-sur-Mer to Cadarache was widened and strengthened so that the heaviest and largest parts of the tokamak could be delivered to the site. In the photo: a transporter with a test load weighing 800 tons.

From the world via tokamak

Precision control of a fusion reactor requires precise diagnostic tools. One of the key tasks of ITER is to select the most suitable of the five dozen instruments that are currently being tested, and to begin the development of new ones.

At least nine diagnostic devices will be developed in Russia. Three are at the Moscow Kurchatov Institute, including a neutron beam analyzer. The accelerator sends a focused stream of neutrons through the plasma, which undergoes spectral changes and is captured by the receiving system. Spectrometry with a frequency of 250 measurements per second shows the temperature and density of the plasma, force electric field and particle rotation speed are parameters necessary to control the reactor for long-term plasma confinement.

The Ioffe Research Institute is preparing three instruments, including a neutral particle analyzer that captures atoms from the tokamak and helps monitor the concentration of deuterium and tritium in the reactor. The remaining devices will be made at Trinity, where diamond detectors for the ITER vertical neutron chamber are currently being manufactured. All of the above institutes use their own tokamaks for testing. And in the thermal chamber of the Efremov NIIEFA, fragments of the first wall and the diverter target of the future ITER reactor are being tested.

Unfortunately, the fact that many of the components of a future mega-reactor already exist in the metal does not necessarily mean that the reactor will be built. Over the past decade, the estimated cost of the project has grown from 5 to 16 billion euros, and the planned first launch has been postponed from 2010 to 2020. The fate of ITER depends entirely on the realities of our present, primarily economic and political. Meanwhile, every scientist involved in the project sincerely believes that its success can change our future beyond recognition.

Lasers,

We say that we will put the sun into a box. The idea is pretty. The problem is we don't know how to make the box.

Pierre-Gilles de Gennes
French Nobel laureate

Everyone electronic devices and machines need energy and humanity consumes a lot of it. But fossil fuels are running out, and alternative energy is not yet effective enough.
There is a method of obtaining energy that ideally suits all requirements - Thermonuclear fusion. The reaction of thermonuclear fusion (the conversion of hydrogen into helium and the release of energy) constantly occurs in the sun and this process gives the planet energy in the form sun rays. You just need to imitate it on Earth, on a smaller scale. It is enough to provide high pressure and very high temperature (10 times higher than on the Sun) and the fusion reaction will be launched. To create such conditions, you need to build a thermonuclear reactor. It will use more abundant resources on earth, will be safer and more powerful than conventional nuclear power plants. For more than 40 years, attempts have been made to build it and experiments have been conducted. In recent years, one of the prototypes even managed to obtain more energy than was expended. The most ambitious projects in this area are presented below:

Government projects

Most public attention Lately goes to another thermonuclear reactor design - the Wendelstein 7-X stellarator (the stellarator is more complex in its internal structure than ITER, which is a tokamak). Having spent just over $1 billion, German scientists built a scaled-down demonstration model of the reactor in 9 years by 2015. If he shows good results A larger version will be built.

France's MegaJoule Laser will be the world's most powerful laser and will attempt to advance a laser-based method of building a fusion reactor. The French installation is expected to be commissioned in 2018.

NIF (National Ignition Facility) was built in the USA over 12 years and 4 billion dollars by 2012. They expected to test the technology and then immediately build a reactor, but it turned out that, as Wikipedia reports, significant work is required if the system is ever to reach ignition. As a result, grandiose plans were canceled and scientists began to gradually improve the laser. The final challenge is to raise energy transfer efficiency from 7% to 15%. Otherwise, congressional funding for this method of achieving synthesis may cease.

At the end of 2015, construction began on a building for the world’s most powerful laser installation in Sarov. It will be more powerful than the current American and future French ones and will make it possible to conduct experiments necessary for the construction of a “laser” version of the reactor. Completion of construction in 2020.

Located in the USA, the MagLIF fusion laser is recognized as a dark horse among methods for achieving thermonuclear fusion. Recently, this method has shown better results than expected, but the power still needs to be increased by 1000 times. The laser is currently undergoing an upgrade, and by 2018 scientists hope to receive the same amount of energy as they spent. If successful, a larger version will be built.

The Russian Nuclear Physics Institute persistently experimented with the “open trap” method, which the United States abandoned in the 90s. As a result, indicators were obtained that were considered impossible for this method. BINP scientists believe that their installation is now at the level of the German Wendelstein 7-X (Q=0.1), but cheaper. Now they are building a new installation for 3 billion rubles

The head of the Kurchatov Institute constantly reminds of plans to build a small thermonuclear reactor in Russia - Ignitor. According to the plan, it should be as effective as ITER, albeit smaller. Its construction should have started 3 years ago, but this situation is typical for large scientific projects.

At the beginning of 2016, the Chinese tokamak EAST managed to reach a temperature of 50 million degrees and maintain it for 102 seconds. Before the construction of huge reactors and lasers began, all the news about thermonuclear fusion was like this. One might think that this is just a competition among scientists to see who can hold the increasingly higher temperature longer. The higher the plasma temperature and the longer it can be maintained, the closer we are to the beginning of the fusion reaction. There are dozens of such installations in the world, several more () () are being built, so the EAST record will soon be broken. In essence, these small reactors are just testing equipment before being sent to ITER.

Lockheed Martin announced a fusion energy breakthrough in 2015 that would allow them to build a small and mobile fusion reactor within 10 years. Given that even very large and not at all mobile commercial reactors were not expected until 2040, the corporation's announcement was met with skepticism. But the company has a lot of resources, so who knows. A prototype is expected in 2020.

Popular Silicon Valley startup Helion Energy has its own unique plan to achieve thermonuclear fusion. The company has raised more than $10 million and expects to create a prototype by 2019.

Low-profile startup Tri Alpha Energy has recently achieved impressive results in promoting its fusion method (theorists have developed >100 theoretical ways to achieve fusion, the tokamak is simply the simplest and most popular). The company also raised more than $100 million in investor funds.

The reactor project from the Canadian startup General Fusion is even more different from the others, but the developers are confident in it and have raised more than $100 million in 10 years to build the reactor by 2020.

UK startup First light has the most accessible website, formed in 2014, and announced plans to use the latest scientific data to achieve nuclear fusion at a lower cost.

Scientists from MIT wrote a paper describing a compact fusion reactor. They rely on new technologies that appeared after the construction of giant tokamaks began and promise to complete the project in 10 years. It is not yet known whether they will be given the green light to begin construction. Even if approved, an article in a magazine is even more early stage than a startup

Nuclear fusion is perhaps the least suitable industry for crowdfunding. But it is with his help and also with NASA funding that the Lawrenceville Plasma Physics company is going to build a prototype of its reactor. Of all the ongoing projects, this one looks the most like a scam, but who knows, maybe they will bring something useful to this grandiose work.

ITER will only be a prototype for the construction of a full-fledged DEMO installation - the first commercial fusion reactor. Its launch is now scheduled for 2044 and this is still an optimistic forecast.

But there are plans for the next stage. A hybrid thermonuclear reactor will receive energy from both atomic decay (like a conventional nuclear power plant) and fusion. In this configuration, the energy can be 10 times more, but the safety is lower. China hopes to build a prototype by 2030, but experts say that would be like trying to build hybrid cars before the invention of the internal combustion engine.

Bottom line

There is no shortage of people wanting to bring a new source of energy into the world. The ITER project has the greatest chance, given its scale and funding, but other methods, as well as private projects, should not be discounted. Scientists have worked for decades to get the fusion reaction going without much success. But now there are more projects to achieve thermonuclear reaction than ever before. Even if each of them fails, new attempts will be made. It's unlikely that we will rest until we light up a miniature version of the Sun, here on Earth.

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• fusion reactor
• energy
• future projects

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