“Lockheed Martin has begun developing a compact thermonuclear reactor... The company’s website says that the first prototype will be built within a year. If this turns out to be true, in a year we will live in a completely different world,” this is the beginning of one of “The Attic.” Three years have passed since its publication, and the world has not changed that much since then.

Today in reactors nuclear power plants energy is generated by the decay of heavy nuclei. In thermonuclear reactors, energy is obtained during the process of fusion of nuclei, during which nuclei of less mass than the sum of the original ones are formed, and the “residue” is lost in the form of energy. Nuclear reactor waste is radioactive, its safe disposal is a major headache. Fusion reactors do not have this drawback, and also use widely available fuel such as hydrogen.

They have only one big problem - industrial designs don't exist yet. The task is not easy: for thermonuclear reactions, fuel must be compressed and heated to hundreds of millions of degrees - hotter than on the surface of the Sun (where thermonuclear reactions occur naturally). It is difficult to achieve such a high temperature, but it is possible, but such a reactor consumes more energy than it produces.

However, they still have so many potential advantages that, of course, not only Lockheed Martin is involved in development.

ITER

ITER is the largest project in this area. It involves the European Union, India, China, Korea, Russia, the USA and Japan, and the reactor itself has been built on French territory since 2007, although its history goes much deeper into the past: Reagan and Gorbachev agreed on its creation in 1985. The reactor is a toroidal chamber, a “donut”, in which the plasma is held by magnetic fields, which is why it is called a tokamak - That roidal ka measure with ma rotten To atushki. The reactor will generate energy through the fusion of hydrogen isotopes - deuterium and tritium.

It is planned that ITER will receive 10 times more energy than it consumes, but this will not happen soon. It was initially planned that the reactor would begin operating in experimental mode in 2020, but then this date was postponed to 2025. At the same time industrial production energy will begin no earlier than 2060, and we can only expect the spread of this technology somewhere at the end of the 21st century.

Wendelstein 7-X

Wendelstein 7-X is the largest stellarator-type fusion reactor. The stellarator solves the problem that plagues tokamaks - the “spreading” of plasma from the center of the torus to its walls. What the tokamak tries to cope with due to the power of the magnetic field, the stellarator solves due to its complex shape: The magnetic field confining the plasma bends to stop the advances of charged particles.

Wendelstein 7-X, as its creators hope, will be able to operate for half an hour in 21, which will give a “ticket to life” to the idea of ​​thermonuclear stations of a similar design.

National Ignition Facility

Another type of reactor uses powerful lasers to compress and heat fuel. Alas, the largest laser installation for producing thermonuclear energy, the American NIF, was unable to produce more energy than it consumes.

Which of all these projects will really take off and which will suffer the same fate as NIF is difficult to predict. All we have to do is wait, hope and follow the news: the 2020s promise to be interesting time for nuclear energy.

“Nuclear Technologies” is one of the profiles of the NTI Olympiad for schoolchildren.

Fusion power plant.

Currently, scientists are working on the creation of a thermonuclear power plant, the advantage of which is to provide humanity with electricity for an unlimited time. A thermonuclear power plant operates on the basis of thermonuclear nuclear fusion— reactions of synthesis of heavy hydrogen isotopes with the formation of helium and the release of energy. The thermonuclear fusion reaction does not produce gaseous or liquid radioactive waste and does not produce plutonium, which is used for production nuclear weapons. If we also take into account that the fuel for thermonuclear stations will be the heavy hydrogen isotope deuterium, which is obtained from simple water - half a liter of water contains fusion energy equivalent to that obtained by burning a barrel of gasoline - then the advantages of power plants based on thermonuclear nuclear reaction, become obvious.

During a thermonuclear reaction, energy is released when light atoms combine and transform into heavier ones. To achieve this, it is necessary to heat the gas 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 and neutrons and releasing a large amount of energy. A commercial power plant operating on this principle would use the energy of neutrons moderated by a layer of dense material (lithium).

Compared to a nuclear power plant, a fusion reactor will leave behind much less radioactive waste.

International thermonuclear reactor ITER

Participants in the international consortium to create the world's first thermonuclear reactor, ITER, signed an agreement in Brussels that launches the practical implementation of the project.

Representatives of the European Union, the United States, Japan, China, South Korea and Russia intend to begin construction of the experimental reactor in 2007 and complete it within eight years. If everything goes according to plan, then by 2040 a demonstration power plant operating on the new principle could be built.

I would like to believe that the era of environmentally hazardous hydroelectric and nuclear power plants will soon end, and the time will come for a new power plant - a thermonuclear one, the project of which is already being implemented. But, despite the fact that the ITER (International Thermonuclear Reactor) project is almost ready; Despite the fact that already at the first operating experimental thermonuclear reactors a power exceeding 10 MW was obtained - the level of the first nuclear power plants, the first thermonuclear power plant will not work earlier than in twenty years, because its cost is very high. The cost of the work is estimated at 10 billion euros - this is the most expensive international project power plants. Half of the costs of constructing the reactor are covered by the European Union. Other consortium participants will allocate 10% of the estimate.

Now the plan for the construction of a reactor, which will become the most expensive joint scientific project Afterwards, parliamentarians of the consortium participating countries must ratify it.

The reactor will be built in the southern French province of Provence, in the vicinity of the city of Cadarache, where the French nuclear research center is located.

fusion reactor

fusion reactor

Currently being developed. (80s) a device for obtaining energy through reactions of synthesis of light at. nuclei occurring at very high temperatures (=108 K). Basic The requirement that thermonuclear reactions must satisfy is that the energy release as a result of thermonuclear reactions more than compensates for the energy costs from external sources. sources to maintain the reaction.

There are two types of T. r. The first type includes TR, to-Crimea is necessary from external. sources only for ignition of thermonuclear fusions. reactions. Further reactions are supported by the energy released in the plasma during fusion. reactions; for example, in a deuterium-tritium mixture, the energy of a-particles formed during reactions is consumed to maintain a high plasma temperature. In stationary operating mode T.r. the energy carried by a-particles compensates for the energy. losses from the plasma, mainly due to thermal conductivity of the plasma and radiation. To this type of T. r. applies, for example, .

To other type of T. r. Reactors include reactors in which the energy released in the form of a-particles is not enough to maintain the combustion of reactions, but energy from external sources is required. sources. This happens in those reactors in which the energy levels are high. losses, e.g. open magnetic trap.

T.r. can be built on the basis of systems with magnetic. plasma confinement, such as tokamak, open magnetic. trap, etc., or systems with inertial plasma confinement, when the plasma is short time(10-8-10-7 s) energy is introduced (either using laser radiation, or using beams of relativistic electrons or ions), sufficient for the occurrence and maintenance of reactions. T.r. with magnetic plasma confinement can operate in quasi-stationary or stationary modes. In the case of inertial plasma confinement T. r. must operate in short pulse mode.

T.r. characterized by coefficient. power amplification (quality factor) Q, equal to the ratio of the thermal power obtained in the reactor to the power cost of its production. Thermal T.r. consists of the power released during fusion. reactions in plasma, and the power released in the so-called. TR blanket - a special shell surrounding the plasma, which uses the energy of thermonuclear nuclei and neutrons. The most promising technology appears to be one that operates on a deuterium-tritium mixture due to the higher reaction rate than other fusion reactions.

T.r. on deuterium-tritium fuel, depending on the composition of the blanket, it can be “pure” or hybrid. Blanket of “pure” T. r. contains Li; in it, under the influence of neutrons, it is produced that “burns” in the deuterium-tritium plasma, and the energy of the thermonuclears increases. reactions from 17.6 to 22.4 MeV. In the blanket of a hybrid T. r. Not only is tritium produced, but there are zones in which, when 238U is placed in them, 239Pu can be obtained (see NUCLEAR REACTOR). At the same time, energy is released in the blanket equal to approx. 140 MeV per one thermonuclear. . Thus, in hybrid T. r. it is possible to obtain approximately six times more energy than in a “pure” nuclear reactor, but the presence of fissile radioacts in the former. in-in creates an environment close to the one in which there is a poison. fission reactors.

Physical encyclopedic dictionary. - M.: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1983 .

fusion reactor

Developed in the 1990s. device for obtaining energy through lung synthesis reactions atomic nuclei, occurring in plasma at very high temp-pax (10 8 K). Basic The requirement that T.R. must satisfy is that the energy release as a result thermonuclear reactions(TP) more than compensated for energy costs from external sources. sources to maintain the reaction.

There are two types of T. r. The first includes reactors, which generate energy from external sources. sources is only necessary for ignition of TP. Further reactions are supported by the energy released in the plasma at TP, for example. in a deuterium-tritium mixture, the energy of a-particles formed during reactions is consumed to maintain a high temperature. In a mixture of deuterium with 3 He, the energy of all reaction products, i.e. a-particles and protons, is spent on maintaining the required plasma temperature. In stationary operating mode T.r. energy that carries a charge. reaction products, compensates for energy. losses from plasma caused mainly by plasma thermal conductivity and radiation. Such reactors are called reactors with ignition of a self-sustaining thermonuclear reaction (see. Ignition criterion). An example of such a T.r.: tokamak, stellarator.

To other types of T. r. Reactors include reactors in which the energy released in the plasma in the form of charges is insufficient to maintain the combustion of reactions. reaction products, but energy is needed from external sources. sources. Such reactors are usually called reactors supporting the combustion of thermonuclear reactions. This happens in those T. rivers where the energy is high. losses, e.g. open mag. trap, tokamak, operating in a mode with plasma density and temperature below the ignition curve TP. These two types of reactors include all possible types of T. r., which can be built on the basis of systems with magnetic. plasma confinement (tokamak, stellarator, open magnetic trap, etc.) or systems with inertial hold plasma.

International thermonuclear experimental reactor ITER: 1 - central ; 2 - blanket - ; 3 - plasma; 4 - vacuum wall; 5 - pumping pipeline; 6- cryostat; 7- active control coils; 8 - toroidal magnetic field coils; 9 - first wall; 10 - divertor plates; 11 - poloidal magnetic field coils.

A reactor with inertial plasma confinement is characterized by the fact that in a short time (10 -8 -10 -7 s) energy is introduced into it using either laser radiation or beams of relativistic electrons or ions, sufficient for the occurrence and maintenance of TP. Such a reactor will only operate in short pulse mode, unlike a reactor with a magnet. plasma confinement, which can operate in quasi-stationary or even stationary modes.

T.r. characterized by coefficient. power gain (quality factor) Q, equal to the ratio of the thermal power of the reactor to the power costs of its production. The thermal power of the reactor consists of the power released during TP in the plasma, the power introduced into the plasma to maintain the combustion temperature TP or maintain a stationary current in the plasma in the case of a tokamak, and the power released in the plasma.

Development of T.r. with magnetic retention is more advanced than inertial retention systems. Scheme of the International Thermonuclear Experiment. The ITER tokamak reactor, a project which has been developed since 1988 by four parties - the USSR (since 1992 Russia), the USA, the Euratom countries and Japan, is presented in the figure. T.r. has . parameters: large plasma radius 8.1 m; small plasma radius in avg. plane 3 m; plasma cross-section elongation 1.6; toroidal mag. on axis 5.7 Tesla; rated plasma 21 MA; rated thermonuclear power with DT fuel 1500 MW. The reactor contains traces. basic nodes: center. solenoid I, electric the field of which carries out, regulates the increase in current and maintains it together with special. system will be supplemented plasma heating; first wall 9, the edges are directly facing the plasma and perceive heat flows in the form of radiation and neutral particles; blanket - protection 2, which phenomena an integral part of T. r. on deuterium-tri-tium (DT) fuel, since the tritium burned in the plasma is reproduced in the blanket. T.r. on DT fuel, depending on the material of the blanket, it can be “pure” or hybrid. Blanket of "clean" T. r. contains Li; in it, under the influence of thermonuclear neutrons, tritium is produced: 6 Li +nT+ 4 He+ 4.8 MeV, and the TP energy increases from 17.6 MeV to 22.4 MeV. In the blank hybrid fusion reactor Not only is tritium produced, but there are zones in which waste 238 U is placed to produce 239 Pu. At the same time, energy equal to 140 MeV per thermonuclear neutron is released in the blanket. T. o., in a hybrid T. r. it is possible to obtain approximately six times more energy per initial fusion event than in “pure” T.R., but the presence in the first case of fissile radioacts. substances creates radiation. an environment similar to that of heaven that exists in nuclear reactors division.

In T.r. with fuel on a mixture of D with 3 He, there is no blanket, since there is no need to reproduce tritium: D + 3 He 4 He (3.6 MeV) + p (14.7 MeV), and all the energy is released in the form of charge. reaction products. Radiation The protection is designed to absorb the energy of neutrons and radioactive acts. radiation and reduction of heat and radiation flows to the superconducting magnet. system to a level acceptable for stationary operation. Toroidal magnet coils fields 8 serve to create a toroidal magnet. fields and are made superconducting using an Nb 3 Sn superconductor and a copper matrix operating at the temperature of liquid helium (4.2 K). The development of technology for obtaining high-temperature superconductivity may make it possible to eliminate the cooling of coils with liquid helium and switch to a cheaper cooling method, for example. liquid nitrogen. The design of the reactor will not change significantly. Poloidal field coils 11 are also superconducting and, together with magnesium. the plasma current field creates an equilibrium configuration of the poloidal magnetic field. fields with one or two-zero poloidal d i v e r t o r 10, serving to remove heat from the plasma in the form of a flow of charges. particles and for pumping out reaction products neutralized on the divertor plates: helium and protium. In T.r. with D 3 He fuel, divertor plates can serve as one of the elements of the direct charge energy conversion system. reaction products into electricity. Cryostat 6 serves to cool superconducting coils to the temperature of liquid helium or higher temperatures when using more advanced high-temperature superconductors. Vacuum chamber 4 and pumping means 5 are designed to obtain a high vacuum in the working chamber of the reactor, in which plasma is created 3, and in all auxiliary volumes, including the cryostat.

As a first step towards the creation of thermonuclear energy, a thermonuclear reactor is proposed that operates on a DT mixture due to the higher reaction rate than other fusion reactions. In the future, the possibility of creating a low-radioactive T. r. is being considered. on a mixture of D with 3 He, in which bas. energy carries a charge. reaction products, and neutrons appear only in DD and DT reactions during the burnout of tritium generated in DD reactions. As a result, biol. danger T. r. may apparently be reduced by four to five orders of magnitude compared to nuclear reactors division, there is no need for industrial radioact processing materials and their transportation, the disposal of radioactive materials is qualitatively simplified. waste. However, the prospects for creating an environmentally friendly TR in the future. on a mixture of D with 3 Not complicated by the problem of raw materials: natural. concentrations of the 3 He isotope on Earth are parts per million of the 4 He isotope. Therefore, the difficult question of obtaining raw materials arises, e.g. by delivering it from the Moon.

Refers to "Thermonuclear energy"

Fusion reactor E.P. Velikhov, S.V. Putvinsky

THERMONUCLEAR ENERGY.
STATUS AND ROLE IN THE LONG TERM.

E.P. Velikhov, S.V. Putvinsky.
Report dated October 22, 1999, carried out as part of the Energy Center of the World Federation of Scientists

Annotation

This article provides brief overview the current state of thermonuclear research and outlines the prospects for thermonuclear energy in the energy system of the 21st century. The review is intended for a wide range of readers familiar with the basics of physics and engineering.

According to modern physical representation, there are only a few fundamental sources of energy that, in principle, can be mastered and used by humanity. Nuclear fusion reactions are one such source of energy and... In fusion reactions, energy is produced due to the work of nuclear forces performed during the fusion of nuclei of light elements and the formation of heavier nuclei. These reactions are widespread in nature - it is believed that the energy of stars, including the Sun, is produced as a result of a chain of nuclear fusion reactions that convert four nuclei of a hydrogen atom into a helium nucleus. We can say that the Sun is a large natural thermonuclear reactor that supplies energy to the Earth's ecological system.

Currently, more than 85% of the energy produced by humans is obtained by burning organic fuels - coal, oil and natural gas. This cheap source energy and, mastered by man about 200 - 300 years ago, led to rapid development human society, its well-being and, as a result, to the growth of the Earth's population. It is assumed that due to population growth and more uniform energy consumption across regions, energy production will increase by about three times by 2050 compared to the current level and reach 10 21 J per year. There is no doubt that in the foreseeable future the previous source of energy - organic fuels - will have to be replaced by other types of energy production. This will happen both due to the depletion of natural resources and due to environmental pollution, which, according to experts, should occur much earlier than cheap ones will be developed. natural resources(the current method of energy production uses the atmosphere as a garbage dump, emitting 17 million tons of carbon dioxide and other gases accompanying the combustion of fuels every day). The transition from fossil fuels to large-scale alternative energy is expected in the middle of the 21st century. It is assumed that the future energy system will use a variety of energy sources, including renewable energy sources, more widely than the current energy system, such as solar energy, wind energy, hydroelectric power, growing and burning biomass and nuclear energy. The share of each energy source in the total energy production will be determined by the structure of energy consumption and the economic efficiency of each of these energy sources.

In today's industrial society, more than half of the energy is used in a constant consumption mode, independent of the time of day and season. Superimposed on this constant base power are daily and seasonal variations. Thus, the energy system must consist of base energy, which supplies energy to society at a constant or quasi-permanent level, and energy resources, which are used as needed. It is expected that renewable energy sources such as solar energy, biomass combustion, etc. will be used mainly in the variable component of energy consumption and. The main and only candidate for base energy is nuclear energy. Currently, only nuclear fission reactions, which are used in modern nuclear power plants, have been mastered to produce energy. Controlled thermonuclear fusion is, so far, only a potential candidate for basic energy.

What advantages does thermonuclear fusion have over nuclear fission reactions, which allow us to hope for the large-scale development of thermonuclear energy? The main and fundamental difference is the absence of long-lived radioactive waste, which is typical for nuclear fission reactors. And although during the operation of a thermonuclear reactor the first wall is activated by neutrons, the choice of suitable low-activation structural materials opens up the fundamental possibility of creating a thermonuclear reactor in which the induced activity of the first wall will decrease to a completely safe level thirty years after the reactor is shut down. This means that an exhausted reactor will need to be mothballed for only 30 years, after which the materials can be recycled and used in a new synthesis reactor. This situation is fundamentally different from fission reactors, which produce radioactive waste that requires reprocessing and storage for tens of thousands of years. In addition to low radioactivity, thermonuclear energy has huge, practically inexhaustible reserves of fuel and other necessary materials, sufficient to produce energy for many hundreds, if not thousands of years.

It was these advantages that prompted the major nuclear countries to begin large-scale research on controlled thermonuclear fusion in the mid-50s. By this time, the Soviet Union and the United States had already carried out the first successful tests of hydrogen bombs, which confirmed the fundamental possibility of using energy and nuclear fusion in terrestrial conditions. From the very beginning, it became clear that controlled thermonuclear fusion had no military application. The research was declassified in 1956 and has since been carried out within the framework of broad international cooperation. The hydrogen bomb was created in just a few years, and at that time it seemed that the goal was close, and that the first large experimental facilities, built in the late 50s, would produce thermonuclear plasma. However, it took more than 40 years of research to create conditions under which the release of thermonuclear power is comparable to the heating power of the reacting mixture. In 1997, the largest thermonuclear installation, the European TOKAMAK (JET), received 16 MW of thermonuclear power and came close to this threshold.

What was the reason for this delay? It turned out that in order to achieve the goal, physicists and engineers had to solve a lot of problems that they had no idea about at the beginning of their journey. During these 40 years, the science of plasma physics was created, which made it possible to understand and describe the complex physical processes occurring in the reacting mixture. Engineers needed to solve no less complex problems, including learning how to create deep vacuum in large volumes, selecting and testing suitable construction materials, develop large superconducting magnets, powerful lasers and X-ray sources, develop pulsed power systems capable of creating powerful beams of particles, develop methods for high-frequency heating of the mixture, and much more.

§4 is devoted to a review of research in the field of magnetic controlled fusion, which includes systems with magnetic confinement and pulsed systems. Most of this review is devoted to the most advanced systems for magnetic plasma confinement, TOKAMAK-type installations.

The scope of this review allows us to discuss only the most significant aspects of research on controlled thermonuclear fusion. The reader interested in a more in-depth study of various aspects of this problem may be advised to consult the review literature. There is an extensive literature devoted to controlled thermonuclear fusion. In particular, mention should be made of both now classic books written by the founders of controlled thermonuclear research, as well as very recent publications, such as, for example, which outline the current state of thermonuclear research.

Although there are quite a lot of nuclear fusion reactions leading to the release of energy, for practical purposes of using nuclear energy, only the reactions listed in Table 1 are of interest. Here and below we use the standard designation for hydrogen isotopes: p - proton with atomic mass 1, D - deuteron, with atomic mass 2 and T - tritium, isotope with mass 3. All nuclei participating in these reactions with the exception of tritium are stable. Tritium is a radioactive isotope of hydrogen with a half-life of 12.3 years. As a result of β-decay, it turns into He 3, emitting a low-energy electron. Unlike nuclear fission reactions, fusion reactions do not produce long-lived radioactive fragments of heavy nuclei, which makes it possible in principle to create a “clean” reactor, not burdened with the problem of long-term storage of radioactive waste.

Table 1.
Nuclear reactions of interest for controlled fusion

		Energy output, q, (MeV)
	D + T = He 4 + n
	D + D = He 3 + n
	D + He 3 = He 4 + p
	p + B 11 = 3He 4
	Li 6 + n = He 4 + T
	Li 7 + n = He 4 + T + n

All reactions shown in Table 1, except the last one, occur with the release of energy and in the form of kinetic energy and reaction products, q, which is indicated in brackets in units of millions of electron volts (MeV),
(1 eV = 1.6 10 –19 J = 11600 °K). The last two reactions play a special role in controlled fusion - they will be used to produce tritium, which does not exist in nature.

Nuclear fusion reactions 1-5 have a relatively high reaction rate, which is usually characterized by the reaction cross section, σ. The reaction cross sections from Table 1 are shown in Fig. 1 as a function of energy and colliding particles in the center of mass system.

σ

E,

Fig.1. Cross sections for some thermonuclear reactions from Table 1,
as a function of energy and particles in the center of mass system.

Due to the presence of Coulomb repulsion between nuclei, the cross sections for reactions at low energy and particles are negligible, and therefore, at ordinary temperatures, a mixture of hydrogen isotopes and other light atoms practically does not react. In order for any of these reactions to have a noticeable cross section, the colliding particles need to have high kinetic energy. Then the particles will be able to overcome the Coulomb barrier, approach at a distance on the order of nuclear ones, and react. For example, the maximum cross section for the reaction of deuterium with tritium is achieved at a particle energy of about 80 KeV, and in order for a DT mixture to have a high reaction rate, its temperature must be on the scale of one hundred million degrees, T = 10 8 ° K.

The simplest way to produce energy and nuclear fusion that immediately comes to mind is to use an ion accelerator and bombard, say, tritium ions accelerated to an energy of 100 KeV, a solid or gas target containing deuterium ions. However, the injected ions slow down too quickly when colliding with the cold electrons of the target, and do not have time to produce enough energy to cover the energy costs of their acceleration, despite the huge difference in the initial (about 100 KeV) and energy produced in the reaction ( about 10 MeV). In other words, with this “method” of energy production and the energy reproduction rate and,
Q fus = P synthesis / P costs will be less than 1.

In order to increase Q fus, the target electrons can be heated. Then fast ions will decelerate more slowly and Q fus will increase. However, a positive yield is achieved only at a very high target temperature - on the order of several KeV. At this temperature, the injection of fast ions is no longer important; there is a sufficient amount of energetic thermal ions in the mixture, which themselves enter into reactions. In other words, thermonuclear reactions or thermonuclear fusion occur in the mixture.

The rate of thermonuclear reactions can be calculated by integrating the reaction cross section shown in Fig. 1 over the equilibrium Maxwellian particle distribution function. As a result, it is possible to obtain the reaction rate K(T), which determines the number of reactions occurring per unit volume, n 1 n 2 K(T), and, consequently, the volumetric density of energy release in the reacting mixture,

P fus = q n 1 n 2 K(T) (1)

In the last formula n 1 n 2- volume concentrations of reacting components, T- temperature of reacting particles and q- energy yield of the reaction given in Table 1.

At a high temperature characteristic of a reacting mixture, the mixture is in a plasma state, i.e. consists of free electrons and positively charged ions that interact with each other through collective electromagnetic fields. Self-consistent with the motion of plasma particles, electromagnetic fields determine the dynamics of the plasma and, in particular, maintain its quasineutrality. With very high accuracy, the charge densities of ions and electrons in plasma are equal, n e = Zn z, where Z is the charge of the ion (for hydrogen isotopes Z = 1). The ion and electron components exchange energy due to Coulomb collisions and at plasma parameters typical for thermonuclear applications, their temperatures are approximately equal.

You have to pay for the high temperature of the mixture with additional energy costs. First, we need to take into account the bremsstrahlung emitted by electrons when colliding with ions:

The power of bremsstrahlung, as well as the power of thermonuclear reactions in the mixture, is proportional to the square of the plasma density and, therefore, the ratio P fus /P b depends only on the plasma temperature. Bremsstrahlung, in contrast to the power of thermonuclear reactions, weakly depends on the plasma temperature, which leads to the presence of a lower limit on the plasma temperature at which the power of thermonuclear reactions is equal to the power of bremsstrahlung losses, P fus /P b = 1. At temperatures below the threshold bremsstrahlung power losses exceed the thermonuclear release of energy and, and therefore in a cold mixture a positive energy release is impossible. The mixture of deuterium and tritium has the lowest limiting temperature, but even in this case the temperature of the mixture must exceed 3 KeV (3.5 10 7 °K). The threshold temperatures for the DD and DHe 3 reactions are approximately an order of magnitude higher than for the DT reaction. For the reaction of a proton with boron, bremsstrahlung radiation at any temperature exceeds the reaction yield, and, therefore, to use this reaction, special traps are needed in which the electron temperature is lower than the ion temperature, or the plasma density is so high that the radiation is absorbed by the working mixture.

In addition to the high temperature of the mixture, for positive reactions to occur, the hot mixture must exist long enough for the reactions to occur. In any thermonuclear system with final dimensions In addition to bremsstrahlung, there are channels of energy loss from the plasma (for example, due to thermal conductivity, line radiation of impurities, etc.), the power of which should not exceed thermonuclear energy release. In the general case, additional energy losses can be characterized by the energy lifetime of the plasma t E, defined in such a way that the ratio 3nT / t E gives the power loss per unit plasma volume. Obviously, for a positive yield it is necessary that the thermonuclear power exceed the power of additional losses, P fus > 3nT / t E , which gives a condition for the minimum product of density and plasma lifetime, nt E . For example, for a DT reaction it is necessary that

nt E > 5 10 19 s/m 3 (3)

This condition is usually called the Lawson criterion (strictly speaking, in the original work, the Lawson criterion was derived for a specific thermonuclear reactor circuit and, unlike (3), includes the efficiency of converting thermal energy into electrical energy). In the form in which it is written above, the criterion is practically independent of the thermonuclear system and is generalized a necessary condition positive output. The Lawson criterion for other reactions is one or two orders of magnitude higher than for the DT reaction, and the threshold temperature is also higher. The proximity of the device to achieving a positive output is usually depicted on the T - nt E plane, which is shown in Fig. 2.

nt E

Fig.2. Region with a positive yield of a nuclear reaction on the T-nt E plane.
The achievements of various experimental installations for confining thermonuclear plasma are shown.

It can be seen that DT reactions are more easily feasible - they require a significantly lower plasma temperature than DD reactions and impose less stringent conditions on its retention. The modern thermonuclear program is aimed at implementing DT-controlled fusion.

Thus, controlled thermonuclear reactions are, in principle, possible, and the main task of thermonuclear research is the development of a practical device that could compete economically with other sources of energy and.

All devices invented over 50 years can be divided into two large classes: 1) stationary or quasi-stationary systems based on magnetic confinement of hot plasma; 2) pulse systems. In the first case, the plasma density is low and the Lawson criterion is achieved due to good energy retention in the system, i.e. long energy plasma lifetime. Therefore, systems with magnetic confinement have a characteristic plasma size of the order of several meters and relatively low density plasma, n ~ 10 20 m -3 (this is approximately 10 5 times lower than the density of atoms at normal pressure and room temperature).

IN pulse systems Lawson's criterion is achieved by compressing fusion targets with laser or x-ray radiation and creating a very high-density mixture. The lifetime in pulsed systems is short and is determined by the free expansion of the target. Main physical problem, in this direction of controlled fusion, is to reduce the total energy and explosion to a level that will make a practical fusion reactor.

Both types of systems have already come close to creating experimental machines with a positive energy output and Q fus > 1, in which the main elements of future thermonuclear reactors will be tested. However, before moving on to a discussion of fusion devices, we will consider the fuel cycle of a future fusion reactor, which is largely independent of the specific design of the system.

	Large radius R(m)	Small radius, A(m)	Plasma current I p (MA)				Machine Features
							DT plasma, divertor
							Divertor, beams of energetic neutral atoms
							Superconducting magnetic system (Nb 3 Sn)
							Superconducting magnetic system (NbTi)

1) TOKAMAK T-15 has so far operated only in the mode with ohmic heating of the plasma and, therefore, the plasma parameters obtained with this installation are quite low. In the future, it is planned to introduce 10 MW of neutral injection and 10 MW of electron cyclotron heating.

2) The given Q fus was recalculated from the parameters of the DD plasma obtained in the setup to the DT plasma.

And although the experimental program on these TOKAMAKs has not yet been completed, this generation of machines has practically completed the tasks assigned to it. TOKAMAKs JET and TFTR for the first time received high thermonuclear power of DT reactions in plasma, 11 MW in TFTR and 16 MW in JET. Figure 6 shows the time dependences of thermonuclear power in DT experiments.

Fig.6. Dependence of thermonuclear power on time in record deuterium-tritium discharges at the JET and TFTR tokamaks.

This generation of TOKAMAKs reached the threshold value Q fus = 1 and received nt E only several times lower than that required for a full-scale TOKAMAK reactor. TOKAMAKs have learned to maintain a stationary plasma current using RF fields and neutral beams. The physics of plasma heating by fast particles, including thermonuclear alpha particles, was studied, the operation of the divertor was studied, and modes of its operation with low thermal loads were developed. The results of these studies made it possible to create physical basis, necessary for the next step - the first TOKAMAK reactor, which will operate in combustion mode.

What physical restrictions on plasma parameters are there in TOKAMAKs?

Maximum plasma pressure in TOKAMAK or maximum value β is determined by the stability of the plasma and is approximately described by Troyon's relation,

Where β expressed in %, Ip– current flowing in the plasma and β N is a dimensionless constant called the Troyon coefficient. The parameters in (5) have dimensions MA, T, m. Maximum values Troyon coefficient β N= 3÷5, achieved in experiments, are in good agreement with theoretical predictions based on calculations of plasma stability. Fig.7 shows the limit values β , obtained in various TOKAMAKs.

Fig.7. Comparison of limit values β achieved in Troyon scaling experiments.

If exceeded limit value β , large-scale helical disturbances develop in the TOKAMAK plasma, the plasma quickly cools and dies on the wall. This phenomenon is called plasma stall.

As can be seen from Fig. 7, TOKAMAK is characterized by rather low values β at the level of several percent. There is a fundamental possibility to increase the value β by reducing the plasma aspect ratio to extremely low values ​​of R/ a= 1.3÷1.5. Theory predicts that in such machines β can reach several tens of percent. The first ultra-low aspect ratio TOKAMAK, START, built several years ago in England, has already received values β = 30%. On the other hand, these systems are technically more demanding and require special technical solutions for the toroidal coil, divertor and neutron protection. Currently, several larger experimental TOKAMAKs than START are being built with a low aspect ratio and plasma current above 1 MA. It is expected that over the next 5 years, experiments will provide enough data to understand whether the expected improvement in plasma parameters will be achieved and whether it will be able to compensate for the technical difficulties expected in this direction.

Long-term studies of plasma confinement in TOKAMAKs have shown that the processes of energy and particle transfer across the magnetic field are determined by complex turbulent processes in the plasma. And although plasma instabilities responsible for anomalous plasma losses have already been identified, the theoretical understanding of nonlinear processes is not yet sufficient to describe the plasma lifetime based on first principles. Therefore, to extrapolate plasma lifetimes obtained in modern installations to the scale of the TOKAMAK reactor, empirical laws—scalings—are currently used. One of these scalings (ITER-97(y)), obtained through statistical processing of an experimental database from various TOKAMAKs, predicts that the lifetime increases with plasma size, R, plasma current I p, and elongation of the plasma cross section k = b/ A= 4 and decreases with increasing plasma heating power, P:

t E ~ R 2 k 0.9 I р 0.9 / P 0.66

The dependence of the energy lifetime on other plasma parameters is rather weak. Figure 8 shows that the lifetime measured in almost all experimental TOKAMAKs is well described by this scaling.

Fig.8. Dependence of the experimentally observed energy lifetime on the one predicted by ITER-97(y) scaling.
Average deviation experimental points from scaling 15%.
Different labels correspond to different TOKAMAKs and the projected TOKAMAK reactor ITER.

This scaling predicts that a TOKAMAK in which self-sustaining thermonuclear combustion will occur should have a large radius of 7-8 m and a plasma current of 20 MA. In such a TOKAMAK, the energy lifetime will exceed 5 seconds, and the power of thermonuclear reactions will be at the level of 1-1.5 GW.

In 1998, the engineering design of the TOKAMAK reactor ITER was completed. The work was carried out jointly by four parties: Europe, Russia, the USA and Japan with the aim of creating the first experimental TOKAMAK reactor designed to achieve thermonuclear combustion mixtures of deuterium and tritium. The main physical and engineering parameters of the installation are shown in Table 3, and its cross-section is shown in Fig. 9.

Fig.9. General view of the designed TOKAMAK reactor ITER.

ITER will already have all the main features of the TOKAMAK reactor. It will have a fully superconducting magnetic system, a cooled blanket and protection from neutron radiation, and a remote maintenance system for the installation. It is assumed that neutron fluxes with a power density of 1 MW/m 2 and a total fluence of 0.3 MW × yr/m 2 will be obtained on the first wall, which will allow nuclear technology tests of materials and blanket modules capable of reproducing tritium.

Table 3.
Basic parameters of the first experimental thermonuclear TOKAMAK reactor, ITER.

Parameter	Meaning
Major/minor radii of the torus (A/ a)	8.14 m / 2.80 m
Plasma configuration	With one toroidal diverter
Plasma volume
Plasma current
Toroidal magnetic field	5.68 T (at radius R = 8.14 m)
β
Total power of thermonuclear reactions
Neutron flux on the first wall
Burning duration
Additional plasma heating power

ITER is planned to be built in 2010-2011. The experimental program, which will continue on this experimental reactor for about twenty years, will provide plasma-physical and nuclear-technological data necessary for the construction in 2030-2035 of the first demonstration reactor - TOKAMAK, which has already will produce electricity. The main task of ITER will be to demonstrate the practicality of the TOKAMAK reactor for generating electricity and.

Along with TOKAMAK, which is currently the most advanced system for implementing controlled thermonuclear fusion, there are other magnetic traps that successfully compete with TOKAMAK.

	Large radius, R (m)	Small radius, a (m)	Plasma heating power, (MW)	Magnetic field, T	Comments
L H D (Japan)					Superconducting magnetic system, screw diverter
WVII-X (Germany)					Superconducting magnetic system, modular coils, optimized magnetic configuration

In addition to TOKAMAKs and STELLARATORs, experiments, although on a smaller scale, continue on some other systems with closed magnetic configurations. Among them, field-reversed pinches, SPHEROMAKs and compact tori should be noted. Pinches with reversed field have relatively low value toroidal magnetic field. In SFEROMAK or in compact tori there is no toroidal magnetic system at all. Accordingly, all these systems promise the ability to create plasma with a high parameter value β and, therefore, may in the future be attractive for the creation of compact fusion reactors or reactors using alternative reactions, such as DHe 3 or rB, in which a low field is required to reduce magnetic bremsstrahlung. The current plasma parameters achieved in these traps are still significantly lower than those obtained in TOKAMAKS and STELLARATORS.

Installation name	Laser type	Energy per pulse (kJ)	Wavelength
			1.05 / 0.53 / 0.35
NIF (built in USA)
ISKRA 5 (Russia)
DOLPHIN (Russia)
PHEBUS (France)
GEKKO HP (Japan)			1.05 / 0.53 / 0.35

A study of the interaction of laser radiation with matter has shown that laser radiation is well absorbed by the evaporating substance of the target shell up to the required power densities of 2÷4 · 10 14 W/cm 2 . The absorption coefficient can reach 40÷80% and increases with decreasing radiation wavelength. As mentioned above, a large thermonuclear yield can be achieved if the bulk of the fuel remains cold during compression. To do this, it is necessary that the compression be adiabatic, i.e. it is necessary to avoid preheating the target, which can occur due to generation laser radiation energetic electrons, shock waves or hard x-rays. Numerous studies have shown that these unwanted effects can be reduced by profiling the radiation pulse, optimizing the pellets, and reducing the radiation wavelength. Figure 16, borrowed from the work, shows the boundaries of the region on the plane power density - wavelength lasers suitable for target compression.

Fig. 16. The region on the parameter plane in which lasers are capable of compressing thermonuclear targets (shaded).

The first laser installation (NIF) with laser parameters sufficient to ignite targets will be built in the USA in 2002. The installation will make it possible to study the physics of compression of targets, which will have a thermonuclear output at the level of 1-20 MJ and, accordingly, will allow obtaining high values Q>1.

Although lasers allow laboratory tests for compression and ignition of targets, their disadvantage is low efficiency, which, at best, so far reaches 1-2%. At such low efficiencies, the thermonuclear yield of the target must exceed 10 3, which is a very difficult task. In addition, glass lasers have low pulse repeatability. In order for lasers to serve as a reactor driver for a fusion power plant, their cost must be reduced by approximately two orders of magnitude. Therefore, in parallel with the development of laser technology, researchers turned to the development of more efficient drivers - ion beams.

Ion beams

Currently, two types of ion beams are being considered: beams of light ions, type Li, with an energy of several tens of MeV, and beams of heavy ions, type Pb, with an energy of up to 10 GeV. If we talk about reactor applications, then in both cases it is necessary to supply an energy of several MJ to a target with a radius of several millimeters in a time of about 10 ns. It is necessary not only to focus the beam, but also to be able to conduct it in the reactor chamber at a distance of about several meters from the accelerator output to the target, which is not at all an easy task for particle beams.

Beams of light ions with energies of several tens of MeV can be created with relatively high efficiency. using a pulse voltage applied to the diode. Modern pulsed technology makes it possible to obtain the powers required to compress targets, and therefore light ion beams are the cheapest candidate for a driver. Experiments with light ions have been carried out for many years at the PBFA-11 facility at Sandywood National Laboratory in the USA. The setup makes it possible to create short (15 ns) pulses of 30 MeV Li ions with a peak current of 3.5 MA and a total energy of about 1 MJ. A casing made of large-Z material with a target inside was placed in the center of a spherically symmetric diode, allowing for the production of a large number of radially directed ion beams. The ion energy was absorbed in the hohlraum casing and the porous filler between the target and the casing and was converted into soft X-ray radiation, compressing the target.

It was expected to obtain a power density of over 5 × 10 13 W/cm 2 necessary for compressing and igniting targets. However, the achieved power densities were approximately an order of magnitude lower than expected. A reactor using light ions as a driver requires colossal flows of fast particles with a high particle density near the target. Focusing such beams onto millimeter targets is a task of enormous complexity. In addition, light ions will be noticeably inhibited in the residual gas in the combustion chamber.

The transition to heavy ions and high particle energies makes it possible to significantly mitigate these problems and, in particular, to reduce the particle current densities and, thus, alleviate the problem of particle focusing. However, to obtain the required 10 GeV particles, huge accelerators with particle accumulators and other complex accelerating equipment are required. Let us assume that the total beam energy is 3 MJ, the pulse time is 10 ns, and the area on which the beam should be focused is a circle with a radius of 3 mm. Comparative parameters of hypothetical drivers for target compression are given in Table 6.

Table 6.
Comparative characteristics drivers for light and heavy ions.

*) – in the target area

Beams of heavy ions, as well as light ions, require the use of a hohlraum, in which the energy of the ions is converted into X-ray radiation, which uniformly irradiates the target itself. The design of the hohlraum for a heavy ion beam differs only slightly from the hohlraum for laser radiation. The difference is that the beams do not require holes through which the laser beams penetrate into the hohlraum. Therefore, in the case of beams, special particle absorbers are used, which convert their energy into X-ray radiation. One possible option is shown in Fig. 14b. It turns out that the conversion efficiency decreases with increasing energy and ions and increasing the size of the region on which the beam is focused. Therefore, increasing the energy and particles above 10 GeV is impractical.

Currently, both in Europe and in the USA, it has been decided to focus the main efforts on the development of drivers based on heavy ion beams. It is expected that these drivers will be developed by 2010-2020 and, if successful, will replace lasers in next-generation NIF installations. So far, the accelerators required for inertial fusion do not exist. The main difficulty in their creation is associated with the need to increase particle flux densities to a level at which the spatial charge density of ions already significantly affects the dynamics and focusing of particles. In order to reduce the effect of space charge, it is proposed to create a large number of parallel beams, which will be connected in the reactor chamber and directed towards the target. The typical size of a linear accelerator is several kilometers.

How is it supposed to conduct ion beams over a distance of several meters in the reactor chamber and focus them on an area several millimeters in size? One of the possible schemes is self-focusing of beams, which can occur in a gas low pressure. The beam will cause ionization of the gas and a compensating counter electric current flowing through the plasma. The azimuthal magnetic field, which is created by the resulting current (the difference between the beam current and the reverse plasma current), will lead to radial compression of the beam and its focusing. Numerical simulations show that, in principle, such a scheme is possible if the gas pressure is maintained in the desired range of 1-100 Torr.

And although heavy ion beams offer the prospect of creating an effective driver for a fusion reactor, they face enormous technical difficulties that still need to be overcome before the goal is achieved. For thermonuclear applications, an accelerator is needed that will create a beam of 10 GeV ions with a peak current of several tens of spacecraft and an average power of about 15 MW. The volume of the magnetic system of such an accelerator is comparable to the volume of the magnetic system of the TOKAMAK reactor and, therefore, one can expect that their costs will be of the same order.

Pulse reactor chamber

Unlike a magnetic fusion reactor, where high vacuum and plasma purity are required, such requirements are not imposed on the chamber of a pulsed reactor. The main technological difficulties in creating pulsed reactors lie in the field of driver technology, the creation of precision targets and systems that allow feeding and controlling the position of the target in the chamber. The pulse reactor chamber itself has a relatively simple design. Most projects involve the use of a liquid wall created by an open coolant. For example, the HYLIFE-11 reactor design uses molten salt Li 2 BeF 4, a liquid curtain from which surrounds the area where the targets arrive. The liquid wall will absorb neutron radiation and wash away the remains of the targets. It also dampens the pressure of micro-explosions and evenly transfers it to the main wall of the chamber. The characteristic outer diameter of the chamber is about 8 m, its height is about 20 m.

The total flow rate of the coolant liquid is estimated to be about 50 m 3 /s, which is quite achievable. It is assumed that in addition to the main, stationary flow, a pulsed liquid shutter will be made in the chamber, which will open synchronized with the supply of the target with a frequency of about 5 Hz to transmit a beam of heavy ions.

The required accuracy of target feeding is fractions of millimeters. It is obvious that passively delivering a target over a distance of several meters with such precision in a chamber in which turbulent gas flows caused by explosions of previous targets will occur is a practically impossible task. Therefore, the reactor will require a control system that allows tracking the position of the target and dynamically focusing the beam. In principle, such a task is feasible, but it can significantly complicate reactor control.

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 provides the planet with energy in the form sun rays. You just need to imitate it on Earth, on a smaller scale. Enough to provide high blood 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 in Sarov of a building for the world’s most powerful laser installation. It will be more powerful than the current American and future French ones and will allow conducting experiments necessary for the construction of a “laser” version of the reactor. Completion of construction in 2020.

US based laser - MagLIF fusion is recognized dark horse among the 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.

The UK-based startup First light has the most accessible website, formed in 2014, and announced plans to use the latest scientific data to produce 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 an even earlier 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 is unlikely that we will rest until we light up a miniature version of the Sun, here on Earth.

Tags:

• fusion reactor
• energy
• future projects

Add tags