For more than half a century, hard work has been going on in different countries. Scientists are trying to find the key to yet another, the most ambitious energy storehouse. They want to extract energy from water. Many people rightly see a thermonuclear power plant as the only way to liberate humanity from the hydrocarbon trap.
The higher the temperature of a substance, the faster its particles move. But even in plasma, two free atomic nuclei collide with each other without any consequences. The mutual repulsion forces of atomic nuclei are too great. But if you raise the plasma temperature to hundreds of millions of degrees, the energy of fast particles can become higher than the “repulsion barrier.” Then, from two light atomic nuclei, a collision will result in one, heavier nucleus.
And the birth of a new substance will occur with a powerful release of energy
Hydrogen, as the lightest element on Earth, is especially suitable for participating in thermonuclear reactions. More precisely, not the hydrogen that, together with oxygen, makes up ordinary water, but its heavy brother deuterium, whose atomic weight is twice as large. It can be extracted from heavy water, which it forms when combined with oxygen. In nature, for every six thousand drops of ordinary water, there is one drop of heavy water. At first it seems that this is very little, but calculations show: the oceans of our planet alone contain about 38,000 billion tons of heavy water.
If we learn to efficiently extract the energy hidden in it, humanity will be provided with such a reserve for billions of years thanks to thermonuclear power plants.
Thermonuclear reactions (the so-called combination of light atomic nuclei with the formation of heavier nuclei and the release of energy) have already been carried out artificially on Earth. But so far these have been instant, uncontrollable, destructive reactions - explosions of hydrogen (or rather, deuterium) bombs like Kuzkina’s Mother. And if things are going well with thermonuclear weapons, then with a peaceful reactor everything is not so simple.
Physicists from many countries are conducting international research aimed at creating an industrial thermonuclear reactor and building a power plant based on it. Such a reactor will make it possible to master truly inexhaustible reserves of energy and take humanity to a fundamentally new level of existence. Today, existing reactors (tokamak) operate for a short time. During the entire period of research, about 300 thermonuclear reactors were built. Only in 2007 was the first break-even energy reaction produced, when the tokamak produced a quarter (1:1.25) more energy than consumed.
In the near future it is planned to increase this ratio to 1:50. In this regard, tokamaks can only be considered as experimental, but not as industrial installations. Of all the technical problems of modern science, the issue of industrial thermonuclear fusion can be called, without exaggeration, the most ambitious undertaking, capable of revolutionizing ideas about production, ecology, construction, agriculture and transport.
Thermonuclear fusion is capable of radically redrawing both the political and economic map of the world. If any country can have at its disposal a limitless source of clean energy, the deserts will soon bloom, and gasoline and gas will have to be abandoned. Energy-intensive processes, such as metal smelting or aluminum production, can be carried out anywhere. It will become possible to extract and develop previously unprofitable deposits of metals and substances.
New fast fantastic modes of transport will appear
Truly, not a single invention has changed and will change our world as much as the thermonuclear reactor, our little earthly sun. It is clear that the brake on the development of industrial thermonuclear fusion is not only science itself. Fundamental research is underway, but it cannot be said that it is unsuccessful. However, the issue of introducing a working unit into the series encounters the most powerful lobby of raw materials and processing corporations. It is worth considering that the budgets of many oil-producing consortia exceed the budgets of many countries. And these monsters are not going to lose their astronomical income and power.
Therefore, no matter how sad it may sound, we will see an operating thermonuclear reactor, and even more so, a power plant, either by the depletion of oil and gas, or by the exhaustion of the capitalist model of society. Moreover, even after the end of oil and gas, the energy lobby is unlikely to allow everyone to gain access to unlimited energy. And if so, then a sad conclusion suggests itself - a thermonuclear power plant cannot be built and put into production by capitalists. It can only be realized in a socialist society. For corporatocrats, such a reactor is mortally dangerous and work on it will never be completed.
Simply about the complex – Fusion power plants for electricity production
- Gallery of images, pictures, photographs.
- Thermonuclear power plants - fundamentals, opportunities, prospects, development.
- Interesting facts, useful information.
- Green news - Fusion power plants.
- Links to materials and sources – Fusion power plants for electricity production.
Today, many countries are taking part in thermonuclear research. The leaders are the European Union, the United States, Russia and Japan, while programs in China, Brazil, Canada and Korea are rapidly expanding. Initially, fusion reactors in the USA and USSR were associated with the development of nuclear weapons and remained classified until the Atoms for Peace conference, which took place in Geneva in 1958. After the creation of the Soviet tokamak, nuclear fusion research became “big science” in the 1970s. But the cost and complexity of the devices increased to the point where international cooperation became the only way forward.
Thermonuclear reactors in the world
Since the 1970s, the commercial use of fusion energy has been continually delayed by 40 years. However, a lot has happened in recent years that may allow this period to be shortened.
Several tokamaks have been built, including the European JET, the British MAST and the TFTR experimental fusion reactor at Princeton, USA. The international ITER project is currently under construction in Cadarache, France. It will be the largest tokamak when it starts operating in 2020. In 2030, China will build CFETR, which will surpass ITER. Meanwhile, China is conducting research on the experimental superconducting tokamak EAST.
Another type of fusion reactor, stellators, is also popular among researchers. One of the largest, LHD, began work in Japan National Institute in 1998. It is used to find the best magnetic configuration for plasma confinement. The German Max Planck Institute conducted research at the Wendelstein 7-AS reactor in Garching between 1988 and 2002, and currently at the Wendelstein 7-X reactor, whose construction took more than 19 years. Another TJII stellarator is in operation in Madrid, Spain. In the US, Princeton Laboratory (PPPL), which built the first fusion reactor of this type in 1951, stopped construction of NCSX in 2008 due to cost overruns and lack of funding.
In addition, significant advances have been made in inertial fusion research. Construction of the $7 billion National Ignition Facility (NIF) at Livermore National Laboratory (LLNL), funded by the National Nuclear Security Administration, was completed in March 2009. The French Laser Mégajoule (LMJ) began operations in October 2014. Fusion reactors use lasers delivering about 2 million joules of light energy within a few billionths of a second to a target a few millimeters in size to trigger a nuclear fusion reaction. The primary mission of NIF and LMJ is research in support of national military nuclear programs.
ITER
In 1985, the Soviet Union proposed building a next-generation tokamak jointly with Europe, Japan and the United States. The work was carried out under the auspices of the IAEA. Between 1988 and 1990, the first designs for the International Thermonuclear Experimental Reactor ITER, which also means "path" or "journey" in Latin, were created to prove that fusion could produce more energy than it absorbed. Canada and Kazakhstan also took part, mediated by Euratom and Russia respectively.
Six years later, the ITER board approved the first comprehensive reactor design based on established physics and technology, costing $6 billion. Then the United States withdrew from the consortium, which forced them to halve costs and change the project. The result is ITER-FEAT, which costs $3 billion but achieves self-sustaining response and positive power balance.
In 2003, the United States rejoined the consortium, and China announced its desire to participate. As a result, in mid-2005 the partners agreed to build ITER in Cadarache in the south of France. The EU and France contributed half of the €12.8 billion, while Japan, China, South Korea, USA and Russia - 10% each. Japan provided high-tech components, maintained a €1 billion IFMIF facility designed to test materials, and had the right to build the next test reactor. The total cost of ITER includes half the costs for 10 years of construction and half for 20 years of operation. India became the seventh member of ITER at the end of 2005.
Experiments are due to begin in 2018 using hydrogen to avoid activating the magnets. The use of D-T plasma is not expected before 2026.
ITER's goal is to generate 500 MW (at least for 400 s) using less than 50 MW of input power without generating electricity.
Demo's two-gigawatt demonstration power plant will produce large-scale on an ongoing basis. The Demo's conceptual design will be completed by 2017, with construction beginning in 2024. The launch will take place in 2033.
JET
In 1978 the EU (Euratom, Sweden and Switzerland) started the joint European project JET in the UK. JET is today the largest operating tokamak in the world. A similar JT-60 reactor operates at Japan's National Fusion Institute, but only JET can use deuterium-tritium fuel.
The reactor was launched in 1983, and became the first experiment, which resulted in controlled thermonuclear fusion with a power of up to 16 MW for one second and 5 MW of stable power on deuterium-tritium plasma in November 1991. Many experiments have been carried out to study various heating schemes and other techniques.
Further improvements to the JET involve increasing its power. The MAST compact reactor is being developed together with JET and is part of the ITER project.
K-STAR
K-STAR is a Korean superconducting tokamak from the National Fusion Research Institute (NFRI) in Daejeon, which produced its first plasma in mid-2008. ITER, which is the result of international cooperation. The 1.8 m radius Tokamak is the first reactor to use Nb3Sn superconducting magnets, the same ones planned for ITER. During the first stage, completed by 2012, K-STAR had to prove its viability basic technologies and achieve plasma pulses lasting up to 20 s. At the second stage (2013-2017), it is being modernized to study long pulses up to 300 s in H mode and transition to a high-performance AT mode. The goal of the third phase (2018-2023) is to achieve high productivity and efficiency in the long-pulse mode. At stage 4 (2023-2025), DEMO technologies will be tested. The device is not capable of working with tritium and does not use D-T fuel.
K-DEMO
Developed in collaboration with the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) and South Korea's NFRI, K-DEMO is intended to be the next step in commercial reactor development beyond ITER, and will be the first power plant capable of generating power into the electrical grid, namely 1 million kW within a few weeks. It will have a diameter of 6.65 m and will have a reproduction zone module created as part of the DEMO project. The Korean Ministry of Education, Science and Technology plans to invest about a trillion Korean won ($941 million) in it.
EAST
China's Experimental Advanced Superconducting Tokamak (EAST) at the Institute of Physics of China in Hefei created hydrogen plasma at a temperature of 50 million °C and maintained it for 102 s.
TFTR
At the American laboratory PPPL, the experimental fusion reactor TFTR operated from 1982 to 1997. In December 1993, TFTR became the first magnetic tokamak to conduct extensive deuterium-tritium plasma experiments. The following year, the reactor produced a then-record 10.7 MW of controllable power, and in 1995 a temperature record of 510 million °C was reached. However, the facility did not achieve the break-even goal of fusion energy, but successfully met the hardware design goals, making a significant contribution to the development of ITER.
LHD
The LHD at Japan's National Fusion Institute in Toki, Gifu Prefecture, was the largest stellarator in the world. The fusion reactor was launched in 1998 and demonstrated plasma confinement properties comparable to other large facilities. An ion temperature of 13.5 keV (about 160 million °C) and an energy of 1.44 MJ were achieved.
Wendelstein 7-X
After a year of testing, which began in late 2015, helium temperatures briefly reached 1 million °C. In 2016, a hydrogen plasma fusion reactor using 2 MW of power reached a temperature of 80 million °C within a quarter of a second. W7-X is the largest stellarator in the world and is planned to operate continuously for 30 minutes. The cost of the reactor was 1 billion €.
NIF
The National Ignition Facility (NIF) at Livermore National Laboratory (LLNL) was completed in March 2009. Using its 192 laser beams, NIF is able to concentrate 60 times more energy than any previous laser system.
Cold fusion
In March 1989, two researchers, American Stanley Pons and British Martin Fleischman, announced that they had launched a simple tabletop cold fusion reactor operating at room temperature. The process involved the electrolysis of heavy water using palladium electrodes on which deuterium nuclei were concentrated to a high density. The researchers say it produced heat that could only be explained in terms of nuclear processes, and there were fusion byproducts including helium, tritium and neutrons. However, other experimenters were unable to repeat this experiment. Most of the scientific community does not believe that cold fusion reactors are real.
Low energy nuclear reactions
Initiated by claims of "cold fusion", research has continued in the low-energy field with some empirical support, but no generally accepted scientific explanation. Apparently, weak nuclear interactions are used to create and capture neutrons (and not a powerful force, as in their fusion). Experiments involve hydrogen or deuterium passing through a catalytic layer and reacting with a metal. Researchers report an observed release of energy. Main practical example is the interaction of hydrogen with nickel powder with the release of heat, the amount of which is greater than any chemical reaction can produce.
The second half of the 20th century was a period of rapid development of nuclear physics. It became clear that nuclear reactions could be used to produce enormous energy from tiny amounts of fuel. Only nine years passed from the explosion of the first nuclear bomb to the first nuclear power plant, and when a hydrogen bomb was tested in 1952, there were predictions that thermonuclear power plants would come into operation in the 1960s. Alas, these hopes were not justified.
Thermonuclear reactions Of all the thermonuclear reactions, only four are of interest in the near future: deuterium + deuterium (products - tritium and proton, released energy 4.0 MeV), deuterium + deuterium (helium-3 and neutron, 3.3 MeV), deuterium + tritium (helium-4 and neutron, 17.6 MeV) and deuterium + helium-3 (helium-4 and proton, 18.2 MeV). The first and second reactions occur in parallel with equal probability. The resulting tritium and helium-3 “burn” in the third and fourth reactions
The main source of energy for humanity today is the combustion of coal, oil and gas. But their supplies are limited, and combustion products pollute the environment. A coal power plant produces more radioactive emissions than a nuclear power plant of the same power! So why haven't we switched to nuclear energy sources yet? There are many reasons for this, but the main one recently has been radiophobia. Despite the fact that a coal-fired power plant, even during normal operation, harms the health of many more people than emergency emissions at a nuclear power plant, it does so quietly and unnoticed by the public. Accidents at nuclear power plants immediately become the main news in the media, causing general panic (often completely unfounded). However, this does not mean at all that nuclear power there are no objective problems. Radioactive waste causes a lot of trouble: technologies for working with it are still extremely expensive, and the ideal situation when all of it will be completely recycled and used is still far away.
Of all the thermonuclear reactions, only four are of interest in the near future: deuterium + deuterium (products - tritium and proton, released energy 4.0 MeV), deuterium + deuterium (helium-3 and neutron, 3.3 MeV), deuterium + tritium (helium -4 and neutron, 17.6 MeV) and deuterium + helium-3 (helium-4 and proton, 18.2 MeV). The first and second reactions occur in parallel with equal probability. The resulting tritium and helium-3 “burn” in the third and fourth reactions.
From fission to fusion
A potential solution to these problems is the transition from fission reactors to fusion reactors. While a typical fission reactor contains tens of tons of radioactive fuel, which is converted into tens of tons of radioactive waste containing a wide variety of radioactive isotopes, a fusion reactor uses only hundreds of grams, maximum kilograms, of one radioactive isotope of hydrogen, tritium. In addition to the fact that the reaction requires an insignificant amount of this least dangerous radioactive isotope, its production is also planned to be carried out directly at the power plant in order to minimize the risks associated with transportation. The synthesis products are stable (non-radioactive) and non-toxic hydrogen and helium. In addition, unlike a fission reaction, a thermonuclear reaction immediately stops when the installation is destroyed, without creating the danger of a thermal explosion. So why has not a single operational thermonuclear power plant been built yet? The reason is that the listed advantages inevitably entail disadvantages: creating the conditions for synthesis turned out to be much more difficult than initially expected.
Lawson criterion
For a thermonuclear reaction to be energetically favorable, it is necessary to ensure a sufficiently high temperature of the thermonuclear fuel, a sufficiently high density and sufficiently low energy losses. The latter are numerically characterized by the so-called “retention time”, which is equal to the ratio of the thermal energy stored in the plasma to the energy loss power (many people mistakenly believe that the “retention time” is the time during which hot plasma is maintained in the installation, but this is not so) . At a temperature of a mixture of deuterium and tritium equal to 10 keV (approximately 110,000,000 degrees), we need to obtain the product of the number of fuel particles in 1 cm 3 (i.e., plasma concentration) and the retention time (in seconds) of at least 10 14. It does not matter whether we have a plasma with a concentration of 1014 cm -3 and a retention time of 1 s, or a plasma with a concentration of 10 23 and a retention time of 1 ns. This criterion is called the Lawson criterion.
In addition to the Lawson criterion, which is responsible for obtaining an energetically favorable reaction, there is also a plasma ignition criterion, which for the deuterium-tritium reaction is approximately three times greater than the Lawson criterion. “Ignition” means that the fraction of thermonuclear energy that remains in the plasma will be enough to maintain required temperature, and additional heating of the plasma will no longer be required.
Z-pinch
The first device in which it was planned to obtain a controlled thermonuclear reaction was the so-called Z-pinch. In the simplest case, this installation consists of only two electrodes located in a deuterium (hydrogen-2) environment or a mixture of deuterium and tritium, and a battery of high-voltage pulse capacitors. At first glance, it seems that it makes it possible to obtain compressed plasma heated to enormous temperatures: exactly what is needed for a thermonuclear reaction! However, in life, everything turned out, alas, to be far from so rosy. The plasma rope turned out to be unstable: the slightest bend leads to a strengthening of the magnetic field on one side and a weakening on the other; the resulting forces further increase the bending of the rope - and all the plasma “falls out” onto the side wall of the chamber. The rope is not only unstable to bending, the slightest thinning of it leads to an increase in the magnetic field in this part, which compresses the plasma even more, squeezing it into the remaining volume of the rope until the rope is finally “squeezed out.” The compressed part has a high electrical resistance, so the current is interrupted, the magnetic field disappears, and all the plasma dissipates.
The principle of operation of the Z-pinch is simple: electricity generates a ring magnetic field that interacts with the same current and compresses it. As a result, the density and temperature of the plasma through which the current flows increases.
It was possible to stabilize the plasma bundle by applying a powerful external magnetic field to it, parallel to the current, and placing it in a thick conductive casing (as the plasma moves, the magnetic field also moves, which induces an electric current in the casing, tending to return the plasma to its place). The plasma stopped bending and pinching, but it was still far from a thermonuclear reaction on any serious scale: the plasma touches the electrodes and gives off its heat to them.
Modern works in the field of Z-pinch fusion, they suggest another principle for creating thermonuclear plasma: a current flows through a tungsten plasma tube, which creates powerful X-ray radiation, compressing and heating a capsule with thermonuclear fuel located inside the plasma tube, similar to what happens in a thermonuclear bomb. However, these works are purely research in nature (the mechanisms of operation of nuclear weapons are studied), and the energy release in this process is still millions of times less than consumption.
The smaller the ratio of the large radius of the tokamak torus (the distance from the center of the entire torus to the center of the cross-section of its pipe) to the small one (the cross-section radius of the pipe), the greater the plasma pressure can be under the same magnetic field. By reducing this ratio, scientists moved from a circular cross-section of the plasma and vacuum chamber to a D-shaped one (in this case, the role of the small radius is played by half the height of the cross-section). All modern tokamaks have exactly this cross-sectional shape. The limiting case was the so-called “spherical tokamak”. In such tokamaks, the vacuum chamber and plasma are almost spherical in shape, with the exception of a narrow channel connecting the poles of the sphere. The conductors of magnetic coils pass through the channel. The first spherical tokamak, START, appeared only in 1991, so this is a fairly young direction, but it has already shown the possibility of obtaining the same plasma pressure with a three times lower magnetic field.
Cork chamber, stellarator, tokamak
Another option for creating the conditions necessary for the reaction is the so-called open magnetic traps. The most famous of them is the “cork bottle”: a pipe with a longitudinal magnetic field, which strengthens at its ends and weakens in the middle. The field increased at the ends creates a “magnetic plug” (hence the Russian name), or “magnetic mirror” (English - mirror machine), which keeps the plasma from leaving the installation through the ends. However, such retention is incomplete; some charged particles moving along certain trajectories are able to pass through these jams. And as a result of collisions, any particle will sooner or later fall on such a trajectory. In addition, the plasma in the mirror chamber also turned out to be unstable: if in some place a small section of the plasma moves away from the axis of the installation, forces arise that eject the plasma onto the chamber wall. Although the basic idea of the mirror cell was significantly improved (which made it possible to reduce both the instability of the plasma and the permeability of the mirrors), in practice it was not even possible to approach the parameters necessary for energetically favorable synthesis.
Is it possible to make sure that the plasma does not escape through the “plugs”? It would seem that the obvious solution is to roll the plasma into a ring. However, then the magnetic field inside the ring is stronger than outside, and the plasma again tends to go to the chamber wall. The way out of this difficult situation also seemed quite obvious: instead of a ring, make a “figure eight”, then in one section the particle will move away from the axis of the installation, and in another it will return back. This is how scientists came up with the idea of the first stellarator. But such a “figure eight” cannot be made in one plane, so we had to use the third dimension, bending the magnetic field in the second direction, which also led to a gradual movement of the particles from the axis to the chamber wall.
The situation changed dramatically with the creation of tokamak-type installations. The results obtained on the T-3 tokamak in the second half of the 1960s were so stunning for that time that Western scientists came to the USSR with their measuring equipment to verify the plasma parameters yourself. The reality even exceeded their expectations.
These fantastically intertwined tubes are not an art project, but a stellarator chamber bent into a complex three-dimensional curve.
In the hands of inertia
In addition to magnetic confinement, there is a fundamentally different approach to thermonuclear fusion - inertial confinement. If in the first case we try to keep the plasma at a very low concentration for a long time (the concentration of molecules in the air around you is hundreds of thousands of times higher), then in the second case we compress the plasma to a huge density, an order of magnitude higher than the density of the heaviest metals, in the expectation that the reaction will have time to pass in that short time before the plasma has time to scatter to the sides.
Originally, in the 1960s, the plan was to use a small ball of frozen fusion fuel, uniformly irradiated from all sides by multiple laser beams. The surface of the ball should have instantly evaporated and, expanding evenly in all directions, compressed and heated the remaining part of the fuel. However, in practice, the irradiation turned out to be insufficiently uniform. In addition, part of the radiation energy was transferred to the inner layers, causing them to heat up, which made compression more difficult. As a result, the ball compressed unevenly and weakly.
There are a number of modern stellarator configurations, all of which are close to a torus. One of the most common configurations involves the use of coils similar to the poloidal field coils of tokamaks, and four to six conductors twisted around a vacuum chamber with multidirectional current. The complex magnetic field created in this way allows the plasma to be reliably contained without requiring a ring electric current to flow through it. In addition, stellarators can also use toroidal field coils, like tokamaks. And there may be no helical conductors, but then the “toroidal” field coils are installed along a complex three-dimensional curve. Recent developments in the field of stellarators involve the use of magnetic coils and a vacuum chamber very complex shape(a very “crumpled” torus), calculated on a computer.
The problem of unevenness was solved by significantly changing the design of the target. Now the ball is placed inside a special small metal chamber (it is called “holraum”, from the German hohlraum - cavity) with holes through which laser beams enter inside. In addition, crystals are used that convert IR laser radiation into ultraviolet. This UV radiation is absorbed the thinnest layer hohlraum material, which is heated to enormous temperatures and emits in the soft x-ray region. In turn, X-ray radiation is absorbed by a thin layer on the surface of the fuel capsule (ball with fuel). This also made it possible to solve the problem of premature heating of the internal layers.
However, the power of the lasers turned out to be insufficient for a noticeable portion of the fuel to react. In addition, the efficiency of the lasers was very low, only about 1%. For fusion to be energetically beneficial at such a low laser efficiency, almost all of the compressed fuel had to react. When trying to replace lasers with beams of light or heavy ions, which can be generated with much greater efficiency, scientists also encountered a lot of problems: light ions repel each other, which prevents them from focusing, and are slowed down when colliding with residual gas in the chamber, and accelerators It was not possible to create heavy ions with the required parameters.
Magnetic prospects
Most of the hope in the field of fusion energy now lies in tokamaks. Especially after they opened a mode with improved retention. A tokamak is both a Z-pinch rolled into a ring (a ring electric current flows through the plasma, creating a magnetic field necessary to contain it), and a sequence of mirror cells assembled into a ring and creating a “corrugated” toroidal magnetic field. In addition, the toroidal field of the coils and the plasma current field are superimposed perpendicular to the plane torus field created by several individual coils. This additional field, called poloidal, strengthens the magnetic field of the plasma current (also poloidal) on the outside of the torus and weakens it on the inside. Thus, the total magnetic field on all sides of the plasma rope turns out to be the same, and its position remains stable. By changing this additional field, it is possible to move the plasma bundle inside the vacuum chamber within certain limits.
A fundamentally different approach to synthesis is proposed by the concept of muon catalysis. A muon is an unstable elementary particle that has the same charge as an electron, but 207 times more mass. A muon can replace an electron in a hydrogen atom, and the size of the atom decreases by a factor of 207. This allows one hydrogen nucleus to move closer to another without expending energy. But to produce one muon, about 10 GeV of energy is spent, which means it is necessary to perform several thousand fusion reactions per muon to obtain energy benefits. Due to the possibility of a muon “sticking” to the helium formed in the reaction, more than several hundred reactions have not yet been achieved. The photo shows the assembly of the Wendelstein stellarator z-x institute plasma physicists Max Planck.
An important problem of tokamaks for a long time was the need to create a ring current in the plasma. To do this, a magnetic circuit was passed through the central hole of the tokamak torus, the magnetic flux in which was continuously changed. A change in magnetic flux gives rise to a vortex electric field, which ionizes the gas in a vacuum chamber and maintains a current in the resulting plasma. However, the current in the plasma must be maintained continuously, which means that the magnetic flux must continuously change in one direction. This, of course, is impossible, so the current in tokamaks could only be maintained for a limited time (from a fraction of a second to several seconds). Fortunately, the so-called bootstrap current was discovered, which occurs in a plasma without an external vortex field. In addition, methods have been developed to heat the plasma, simultaneously inducing the necessary ring current in it. Together, this provided the potential for maintaining hot plasma for as long as desired. In practice, the record currently belongs to the Tore Supra tokamak, where the plasma continuously “burned” for more than six minutes.
The second type of plasma confinement installation, which has great promise, is stellarators. Over the past decades, the design of stellarators has changed dramatically. Almost nothing remained of the original “eight”, and these installations became much closer to tokamaks. Although the confinement time of stellarators is shorter than that of tokamaks (due to the less efficient H-mode), and the cost of their construction is higher, the behavior of the plasma in them is calmer, which means a longer life of the first inner wall of the vacuum chamber. For the commercial development of thermonuclear fusion, this factor is of great importance.
Selecting a reaction
At first glance, it is most logical to use pure deuterium as a thermonuclear fuel: it is relatively cheap and safe. However, deuterium reacts with deuterium a hundred times less readily than with tritium. This means that to operate a reactor on a mixture of deuterium and tritium, a temperature of 10 keV is sufficient, and to operate on pure deuterium, a temperature of more than 50 keV is required. And the higher the temperature, the higher the energy loss. Therefore, at least for the first time, thermonuclear energy is planned to be built on deuterium-tritium fuel. Tritium will be produced in the reactor itself due to irradiation with the fast lithium neutrons produced in it.
"Wrong" neutrons. In the cult film "9 Days of One Year" main character, while working at a thermonuclear installation, received a serious dose of neutron radiation. However, it later turned out that these neutrons were not produced as a result of a fusion reaction. This is not the director’s invention, but a real effect observed in Z-pinches. At the moment of interruption of the electric current, the inductance of the plasma leads to the generation of a huge voltage - millions of volts. Individual hydrogen ions, accelerated in this field, are capable of literally knocking neutrons out of the electrodes. At first, this phenomenon was indeed taken as a sure sign of a thermonuclear reaction, but subsequent analysis of the neutron energy spectrum showed that they had a different origin.
Improved retention mode. The H-mode of a tokamak is a mode of its operation when, with a high power of additional heating, plasma energy losses sharply decrease. The accidental discovery of the enhanced confinement mode in 1982 is as significant as the invention of the tokamak itself. There is no generally accepted theory of this phenomenon yet, but this does not prevent it from being used in practice. All modern tokamaks operate in this mode, as it reduces losses by more than half. Subsequently, a similar regime was discovered in stellarators, indicating that this is a general property of toroidal systems, but confinement is only improved by about 30% in them.
Plasma heating. There are three main methods of heating plasma to thermonuclear temperatures. Ohmic heating is the heating of plasma due to the flow of electric current through it. This method is most effective in the first stages, since with increasing temperature the plasma decreases electrical resistance. Electromagnetic heating uses electromagnetic waves with a frequency coinciding with the frequency of rotation around the magnetic lines of force of electrons or ions. By injecting fast neutral atoms, a stream of negative ions is created, which are then neutralized, turning into neutral atoms that can pass through the magnetic field to the center of the plasma to transfer their energy there.
Are these reactors? Tritium is radioactive, and powerful neutron irradiation from the D-T reaction creates induced radioactivity in the reactor design elements. We have to use robots, which complicates the work. At the same time, the behavior of a plasma of ordinary hydrogen or deuterium is very close to the behavior of a plasma from a mixture of deuterium and tritium. This led to the fact that throughout history, only two thermonuclear installations fully operated on a mixture of deuterium and tritium: the TFTR and JET tokamaks. At other installations, even deuterium is not always used. So the name “thermonuclear” in the definition of a facility does not at all mean that thermonuclear reactions have ever actually occurred in it (and in those that do occur, pure deuterium is almost always used).
Hybrid reactor. The D-T reaction produces 14 MeV neutrons, which can even fission depleted uranium. The fission of one uranium nucleus is accompanied by the release of approximately 200 MeV of energy, which is more than ten times the energy released during fusion. So existing tokamaks could become energetically beneficial if they were surrounded by a uranium shell. Compared to fission reactors, such hybrid reactors would have the advantage of preventing an uncontrolled chain reaction from developing in them. In addition, extremely intense neutron fluxes should convert long-lived uranium fission products into short-lived ones, which significantly reduces the problem of waste disposal.
Inertial hopes
Inertial fusion is also not standing still. Over the decades of development of laser technology, prospects have emerged to increase the efficiency of lasers by approximately ten times. And in practice, their power has been increased hundreds and thousands of times. Work is also underway on heavy ion accelerators with parameters suitable for thermonuclear use. In addition, the concept of “fast ignition” has been a critical factor in the progress of inertial fusion. It involves the use of two pulses: one compresses the thermonuclear fuel, and the other heats up a small part of it. It is assumed that the reaction that begins in a small part of the fuel will subsequently spread further and cover the entire fuel. This approach makes it possible to significantly reduce energy costs, and therefore make the reaction profitable with a smaller fraction of reacted fuel.
Tokamak problems
Despite the progress of installations of other types, tokamaks at the moment still remain out of competition: if two tokamaks (TFTR and JET) back in the 1990s actually produced a release of thermonuclear energy approximately equal to the energy consumption for heating the plasma (even though such a mode lasted only about a second), then nothing similar could be achieved with other types of installations. Even a simple increase in the size of tokamaks will lead to the feasibility of energetically favorable fusion in them. The international reactor ITER is currently being built in France, which will have to demonstrate this in practice.
However, tokamaks also have problems. ITER costs billions of dollars, which is unacceptable for future commercial reactors. No reactor has operated continuously for even a few hours, let alone for weeks and months, which again is necessary for industrial applications. There is no certainty yet that the materials of the inner wall of the vacuum chamber will be able to withstand prolonged exposure to plasma.
The concept of a tokamak with a strong field can make the project less expensive. By increasing the field by two to three times, it is planned to obtain the required plasma parameters in relatively small installation. This concept, in particular, is the basis for the Ignitor reactor, which, together with Italian colleagues, is now beginning to be built at TRINIT (Trinity Institute for Innovation and Thermonuclear Research) near Moscow. If the engineers’ calculations come true, then at a cost many times lower than ITER, it will be possible to ignite plasma in this reactor.
Forward to the stars!
The products of a thermonuclear reaction fly away in different directions at speeds of thousands of kilometers per second. This makes it possible to create ultra-efficient rocket engines. Their specific impulse will be higher than that of the best electric jet engines, and their energy consumption may even be negative (theoretically, it is possible to generate, rather than consume, energy). Moreover, there is every reason to believe that making a thermonuclear rocket engine will be even easier than a ground-based reactor: there is no problem with creating a vacuum, with thermal insulation of superconducting magnets, there are no restrictions on dimensions, etc. In addition, the generation of electricity by the engine is desirable, but It’s not at all necessary, it’s enough that he doesn’t consume too much of it.
Electrostatic confinement
The concept of electrostatic ion confinement is most easily understood through a setup called a fusor. It is based on a spherical mesh electrode, to which a negative potential is applied. Ions accelerated in a separate accelerator or by the field of the central electrode itself fall inside it and are held there by an electrostatic field: if an ion tends to fly out, the electrode field turns it back. Unfortunately, the probability of an ion colliding with a network is many orders of magnitude higher than the probability of entering into a fusion reaction, which makes an energetically favorable reaction impossible. Such installations have found application only as neutron sources.
In an effort to make a sensational discovery, many scientists strive to see synthesis wherever possible. There have been numerous reports in the press regarding various options for so-called “cold fusion.” Synthesis was discovered in metals “impregnated” with deuterium when an electric current flows through them, during the electrolysis of deuterium-saturated liquids, during the formation of cavitation bubbles in them, as well as in other cases. However, most of these experiments have not had satisfactory reproducibility in other laboratories, and their results can almost always be explained without the use of synthesis.
Continuing the “glorious tradition” that began with the “philosopher’s stone” and then turned into a “perpetual motion machine”, many modern scammers are now offering to buy from them a “cold fusion generator”, “cavitation reactor” and other “fuel-free generators”: about the philosophical Everyone has already forgotten the stone, they don’t believe in perpetual motion, but nuclear fusion now sounds quite convincing. But, alas, in reality such energy sources do not exist yet (and when they can be created, it will be in all news releases). So be aware: if you are offered to buy a device that generates energy through cold nuclear fusion, then they are simply trying to “cheat” you!
According to preliminary estimates, even with modern level technology, it is possible to create thermonuclear rocket engine for a flight to the planets of the solar system (with appropriate funding). Mastering the technology of such engines will increase the speed of manned flights tenfold and will make it possible to have large reserve fuel reserves on board, which will make flying to Mars no more difficult than working on the ISS now. Speeds of 10% of the speed of light will potentially become available for automatic stations, which means it will be possible to send research probes to nearby stars and obtain scientific data during the lifetime of their creators.
The concept of a thermonuclear rocket engine based on inertial fusion is currently considered the most developed. The difference between an engine and a reactor lies in the magnetic field, which directs the charged reaction products in one direction. The second option involves using an open trap, in which one of the plugs is deliberately weakened. The plasma flowing from it will create a reactive force.
Thermonuclear future
Mastering thermonuclear fusion turned out to be many orders of magnitude more difficult than it seemed at first. And although many problems have already been solved, the remaining ones will be enough for the next few decades of hard work of thousands of scientists and engineers. But the prospects that the transformations of hydrogen and helium isotopes open up for us are so great, and the path taken is already so significant that it makes no sense to stop halfway. No matter what numerous skeptics say, the future undoubtedly lies in synthesis.
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 (in terms of one person) is equal to 10.3 kW in the USA (one of the record values), 6.3 kW in the Russian Federation, 5.1 kW in the UK, etc., but, on the other hand, it is equal 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 on nuclear power plants on a large scale, they obtain the energy released during fission reactions of atomic nuclei. 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.
In the most advanced existing installations The Tokamak type has long reached temperatures of the order of 150 M°C, 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 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 fairly cheap receipt required quantity 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 viable.
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.
A reactor based on the principle of thermonuclear fusion does not have radioactive radiation and completely safe for 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.
Russia's interests in the Council International organization on 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, the European states have not yet agreed on how exactly the costs will 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 in Russian capital The symposium “ITER Days in Moscow” was held. 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 the new kind 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. The meeting report is available here.
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 joint project countries 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.
Thermonuclear fusion is a cheap and environmentally friendly way to produce energy. 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 large quantity 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 practical use thermonuclear fusion energy does 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 has been very complex, however (despite insufficient funding and difficulties in selecting centers for the creation of JET and ITER installations), clear progress has been observed in recent years, although an operating 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 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:
“Even if the costs of the ITER project significantly exceed the original estimate, they are unlikely to reach the level of $1 billion per year. This level of expenditure should be considered a very modest price to pay for a very reasonable opportunity to create a new source of energy for all of humanity, especially given the fact that already in this century we will inevitably have to give up the habit of wasteful and reckless burning of fossil fuels.”
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 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. 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 really be driven.
That is, from a technical and scientific point of 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? Experts in different countries, developing their own, not so large-scale thermonuclear projects, argue 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. MIPT associate professor described what energy balance is with a simple example: “We have all seen a fire burn. 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.
Humanity is gradually approaching the border of irreversible depletion of the Earth's hydrocarbon resources. We have been extracting oil, gas and coal from the bowels of the planet for almost two centuries, and it is already clear that their reserves are being depleted at tremendous speed. The leading countries of the world have long been thinking about creating a new source of energy, environmentally friendly, safe from the point of view of operation, with enormous fuel reserves.
Fusion reactor
Today there is a lot of talk about the use of so-called alternative types of energy - renewable sources in the form of photovoltaics, wind energy and hydropower. It is obvious that, due to their properties, these directions can only act as auxiliary sources of energy supply.
As a long-term prospect for humanity, only energy based on nuclear reactions can be considered.
On the one hand, more and more states are showing interest in building nuclear reactors on their territory. But still, a pressing problem for nuclear energy is the processing and disposal of radioactive waste, and this affects economic and environmental indicators. Back in the middle of the 20th century, the world's leading physicists, in search of new types of energy, turned to the source of life on Earth - the Sun, in the depths of which, at a temperature of about 20 million degrees, reactions of synthesis (fusion) of light elements take place with the release of colossal energy.
Domestic specialists handled the task of developing a facility for implementing nuclear fusion reactions under terrestrial conditions best of all. The knowledge and experience in the field of controlled thermonuclear fusion (CTF), obtained in Russia, formed the basis of the project, which is, without exaggeration, the energy hope of humanity - the International Experimental Thermonuclear Reactor (ITER), which is being built in Cadarache (France).
History of thermonuclear fusion
The first thermonuclear research began in countries working on their atomic defense programs. This is not surprising, because at the dawn of the atomic era, the main purpose of the appearance of deuterium plasma reactors was the study of physical processes in hot plasma, knowledge of which was necessary, among other things, for the creation of thermonuclear weapons. According to declassified data, the USSR and the USA began almost simultaneously in the 1950s. work on UTS. But, at the same time, there is historical evidence that back in 1932, the old revolutionary and close friend of the leader of the world proletariat Nikolai Bukharin, who at that time held the post of chairman of the Supreme Economic Council committee and followed the development of Soviet science, proposed to launch a project in the country to study controlled thermonuclear reactions.
The history of the Soviet thermonuclear project is not without a fun fact. The future famous academician and creator of the hydrogen bomb, Andrei Dmitrievich Sakharov, was inspired by the idea of magnetic thermal insulation of high-temperature plasma from a letter from a soldier Soviet army. In 1950, Sergeant Oleg Lavrentyev, who served on Sakhalin, sent a letter to the Central Committee of the All-Union Communist Party in which he proposed using lithium-6 deuteride instead of liquefied deuterium and tritium in a hydrogen bomb, and also creating a system with electrostatic confinement of hot plasma to carry out controlled thermonuclear fusion . The letter was reviewed by the then young scientist Andrei Sakharov, who wrote in his review that he “considers it necessary to have a detailed discussion of Comrade Lavrentiev’s project.”
Already by October 1950, Andrei Sakharov and his colleague Igor Tamm made the first estimates of a magnetic thermonuclear reactor (MTR). The first toroidal installation with a strong longitudinal magnetic field, based on the ideas of I. Tamm and A. Sakharov, was built in 1955 in LIPAN. It was called TMP - a torus with a magnetic field. Subsequent installations were already called TOKAMAK, after the combination of the initial syllables in the phrase “TORIDAL CHAMBER MAGNETIC COIL”. In its classic version, a tokamak is a donut-shaped toroidal chamber placed in a toroidal magnetic field. From 1955 to 1966 At the Kurchatov Institute, 8 such installations were built, on which a lot of different studies were carried out. If before 1969, a tokamak was built outside the USSR only in Australia, then in subsequent years they were built in 29 countries, including the USA, Japan, European countries, India, China, Canada, Libya, Egypt. In total, about 300 tokamaks have been built in the world to date, including 31 in the USSR and Russia, 30 in the USA, 32 in Europe and 27 in Japan. In fact, three countries - the USSR, Great Britain and the USA - were engaged in an unspoken competition to see who would be the first to harness plasma and actually begin producing energy “from water.”
The most important advantage of a thermonuclear reactor is the reduction in radiation biological hazard by approximately a thousand times in comparison with all modern nuclear power reactors.
A thermonuclear reactor does not emit CO2 and does not produce “heavy” radioactive waste. This reactor can be placed anywhere, anywhere.
A step of half a century
In 1985, academician Evgeniy Velikhov, on behalf of the USSR, proposed that scientists from Europe, the USA and Japan work together to create a thermonuclear reactor, and already in 1986 in Geneva an agreement was reached on the design of the installation, which later received the name ITER. In 1992, the partners signed a quadripartite agreement to develop an engineering design for the reactor. The first stage of construction is scheduled to be completed by 2020, when it is planned to receive the first plasma. In 2011, real construction began at the ITER site.
The ITER design follows the classic Russian tokamak, developed back in the 1960s. It is planned that at the first stage the reactor will operate in a pulsed mode with a power of thermonuclear reactions of 400–500 MW, at the second stage the continuous operation of the reactor, as well as the tritium reproduction system, will be tested.
It is not for nothing that the ITER reactor is called the energy future of humanity. Firstly, this is the world’s largest scientific project, because in France it is being built by almost the entire world: the EU + Switzerland, China, India, Japan, South Korea, Russia and the USA are participating. The agreement on the construction of the installation was signed in 2006. European countries contribute about 50% of the project's financing, Russia accounts for approximately 10% of the total amount, which will be invested in the form of high-tech equipment. But Russia’s most important contribution is the tokamak technology itself, which formed the basis of the ITER reactor.
Secondly, this will be the first large-scale attempt to use the thermonuclear reaction that occurs in the Sun to generate electricity. Thirdly, this scientific work should bring very practical results, and by the end of the century the world expects the appearance of the first prototype of a commercial thermonuclear power plant.
Scientists assume that the first plasma at the international experimental thermonuclear reactor will be produced in December 2025.
Why did literally the entire world scientific community begin to build such a reactor? The fact is that many technologies that are planned to be used in the construction of ITER do not belong to all countries at once. One state, even the most highly developed in scientific and technical terms, cannot immediately have a hundred technologies of the highest world level in all fields of technology used in such a high-tech and breakthrough project as a thermonuclear reactor. But ITER consists of hundreds of similar technologies.
Russia surpasses the global level in many thermonuclear fusion technologies. But, for example, Japanese nuclear scientists also have unique competencies in this area, which are quite applicable in ITER.
Therefore, at the very beginning of the project, the partner countries came to agreements about who and what would be supplied to the site, and that this should not just be cooperation in engineering, but an opportunity for each of the partners to receive new technologies from other participants, so that in the future develop them yourself.
Andrey Retinger, international journalist