Nuclear decay and fusion. Thermonuclear fusion

All stars, including our Sun, produce energy using thermonuclear fusion. The scientific world is in trouble. Scientists do not know all the ways in which such fusion (thermonuclear) can be obtained. The fusion of light atomic nuclei and their transformation into heavier ones indicates that energy has been obtained, which can be either controlled or explosive. The latter is used in thermonuclear explosive structures. The controlled thermonuclear process differs from the rest of nuclear energy in that it uses a decay reaction when heavy nuclei are split into lighter ones, but nuclear reactions using deuterium (2 N) and tritium (3 N) - fusion, that is, controlled thermonuclear fusion. In the future, it is planned to use helium-3 (3 He) and boron-11 (11 V).

Dream

One should not confuse the traditional and well-known thermonuclear fusion with what is the dream of today's physicists, in the embodiment of which no one yet believes. This refers to a nuclear reaction at any, even room temperature. Also, this is the absence of radiation and cold thermonuclear fusion. Encyclopedias tell us that a nuclear fusion reaction in atomic-molecular (chemical) systems is a process where significant heating of the substance is not required, but humanity has not yet produced such energy. This is despite the fact that absolutely all nuclear reactions in which fusion occurs are in the state of plasma, and its temperature is millions of degrees.

On the this moment this is not even a dream of physicists, but science fiction writers, but nevertheless, developments have been going on for a long time and persistently. Thermonuclear fusion without the constantly attendant danger of the level of Chernobyl and Fukushima - is this not great goal for the good of mankind? foreign scientific literature gave different names this phenomenon. For example, LENR stands for low-energy nuclear reactions, and CANR stands for chemically induced (assisted) nuclear reactions. Successful implementation of such experiments was declared quite often, representing the most extensive databases. But either the media gave out another "duck", or the results spoke of incorrectly staged experiments. Cold thermonuclear fusion has not yet received truly convincing evidence of its existence.

star element

Hydrogen is the most abundant element in space. Approximately half of the mass of the Sun and most of the other stars falls on its share. Hydrogen is not only in their composition - there is a lot of it in interstellar gas and in gas nebulae. And in the depths of stars, including the Sun, the conditions for thermonuclear fusion are created: there the nuclei of hydrogen atoms are converted into helium atoms, thereby generating enormous energy. Hydrogen is its main source. Every second, our Sun radiates energy equivalent to four million tons of matter into space.

This is what the fusion of four hydrogen nuclei into one helium nucleus gives. When one gram of protons burns, the energy of thermonuclear fusion is released twenty million times more than when the same amount is burned. hard coal. Under terrestrial conditions, the power of thermonuclear fusion is impossible, since such temperatures and pressures as exist in the depths of stars have not yet been mastered by man. Calculations show that for at least another thirty billion years, our Sun will not die out or weaken due to the presence of hydrogen. And on Earth, people are just beginning to understand what hydrogen energy is and what the reaction of thermonuclear fusion is, since working with this gas is very risky, and it is extremely difficult to store it. So far, humanity can only split the atom. And every reactor (nuclear) is built on this principle.

Thermonuclear fusion

Nuclear energy is a product of the splitting of atoms. Synthesis, on the other hand, receives energy in a different way - by combining them with each other, when deadly radioactive waste is not formed, and a small amount of sea water would be enough to produce the same amount of energy as is obtained from burning two tons of coal. In the laboratories of the world it has already been proven that controlled thermonuclear fusion is quite possible. However, power plants that would use this energy have not yet been built, even their construction is not foreseen. But two hundred and fifty million dollars were spent by the United States alone to investigate the phenomenon of controlled thermonuclear fusion.

Then these studies were literally discredited. In 1989, chemists S. Pons (USA) and M. Fleshman (Great Britain) announced to the whole world that they had achieved a positive result and launched thermonuclear fusion. The problems were that scientists were too hasty, not subjecting their discovery to review by the scientific world. The media immediately seized the sensation and filed this claim as the discovery of the century. The verification was carried out later, and not just errors in the experiment were discovered - it was a failure. And then not only journalists succumbed to disappointment, but also many highly respected world-class physicists. The reputable laboratories at Princeton University spent more than fifty million dollars to test the experiment. Thus, cold thermonuclear fusion, the principle of its production, were declared pseudoscience. Only small and scattered groups of enthusiasts continued these studies.

essence

Now the term is proposed to be replaced, and instead of cold nuclear fusion, the following definition will sound: a nuclear process induced by a crystal lattice. This phenomenon is understood as anomalous low-temperature processes, which are simply impossible from the point of view of nuclear collisions in a vacuum - the release of neutrons through the fusion of nuclei. These processes can exist in nonequilibrium solids, stimulated by transformations of elastic energy in the crystal lattice under mechanical influences, phase transitions, sorption or desorption of deuterium (hydrogen). This is an analogue of the already well-known hot thermonuclear reaction, when hydrogen nuclei merge and turn into helium nuclei, releasing colossal energy, but this happens at room temperature.

Cold fusion is more precisely defined as chemically induced photonuclear reactions. Direct cold thermonuclear fusion was never achieved, but completely different strategies were suggested by searches. A thermonuclear reaction is triggered by the generation of neutrons. Mechanical stimulation by chemical reactions leads to the excitation of deep electron shells, giving rise to gamma or X-ray radiation, which is intercepted by the nuclei. That is, a photonuclear reaction occurs. Nuclei decay, and thus generate neutrons and, quite possibly, gamma rays. What can excite internal electrons? Probably a shock wave. From the explosion of conventional explosives.

Reactor

For more than forty years, the world thermonuclear lobby has been spending about a million dollars annually on research into thermonuclear fusion, which is supposed to be obtained using TOKAMAK. However, almost all progressive scientists are against such research, since a positive result is most likely impossible. Western Europe and the United States disappointedly began to dismantle all of its TOKAMAKS. And only in Russia they still believe in miracles. Although many scientists consider this idea an ideal brake alternative to nuclear fusion. What is TOKAMAK? This is one of two thermal projects nuclear reactor, which is a toroidal chamber with magnetic coils. And there is also a stellarator, in which the plasma is kept in a magnetic field, but the coils that induce the magnetic field are external, in contrast to the TOKAMAK.

This is a very complex design. TOKAMAK is quite worthy of the Large Hadron Collider in terms of complexity: more than ten million elements, and the total costs, together with construction and project costs, significantly exceed twenty billion euros. The collider was much cheaper, and maintaining the ISS also costs no more. Toroidal magnets require eighty thousand kilometers of superconducting filament, their total weight exceeds four hundred tons, and the entire reactor weighs about twenty-three thousand tons. The Eiffel Tower, for example, weighs just over seven thousand. The TOKAMAK plasma is eight hundred and forty cubic meters. Height - seventy-three meters, sixty of them - underground. For comparison: the Spasskaya Tower is only seventy-one meters high. The area of ​​the reactor platform is forty-two hectares, like sixty football fields. The plasma temperature is one hundred and fifty million degrees Celsius. At the center of the Sun, it is ten times lower. And all this for the sake of controlled thermonuclear fusion (hot).

Physicists and chemists

But let's get back to the "rejected" discovery of Fleshman and Pons. All of their colleagues claim that they still managed to create conditions where deuterium atoms obey wave effects, nuclear energy is released in the form of heat in accordance with the theory of quantum fields. The latter, by the way, is perfectly developed, but hellishly complex and hardly applicable to the description of some specific phenomena of physics. That is probably why people do not want to prove it. Flashman demonstrates a notch in concrete floor laboratory from an explosion, which he claims was caused by a cold fusion. However, physicists do not believe chemists. I wonder why?

After all, how many opportunities for humanity are closed with the cessation of research in this direction! The problems are simply global, and there are many of them. And they all require a solution. This is an environmentally friendly source of energy, through which it would be possible to decontaminate huge volumes of radioactive waste after the operation of nuclear power plants, desalinate sea water and much more. If we could master the production of energy by turning some elements of the periodic table into completely different ones without using neutron fluxes for this purpose, which create induced radioactivity. But science officially and now considers it impossible to transform any chemical elements into completely different ones.

Rossi-Parkhomov

In 2009, the inventor A. Rossi patented an apparatus called the Rossi Energy Catalyst, which implements cold thermonuclear fusion. This device has been repeatedly demonstrated to the public, but has not been independently verified. Physicist Mark Gibbs on the pages of the journal morally destroyed both the author and his discovery: without an objective analysis, they say, confirming the coincidence of the results obtained with the declared ones, this cannot be science news.

But in 2015, Alexander Parkhomov successfully repeated Rossi's experiment with his low-energy (cold) nuclear reactor (LENR) and proved that the latter has great prospects, although its commercial significance is questionable. Experiments, the results of which were presented at a seminar at the All-Russian Research Institute of Operation nuclear power plants, show that the most primitive copy of the brainchild of Rossi - his nuclear reactor, can produce two and a half times more energy than it consumes.

Energoniva

The legendary scientist from Magnitogorsk, A. V. Vachaev, created the Energoniva installation, with the help of which he discovered a certain effect of transmutation of elements and the generation of electricity in this process. It was hard to believe. Attempts to draw the attention of fundamental science to this discovery were futile. Criticism came from everywhere. Probably, the authors did not need to independently build theoretical calculations regarding the observed phenomena, or the physicists of the higher classical school should have been more attentive to experiments with high-voltage electrolysis.

But on the other hand, such a relationship was noted: not a single detector registered a single radiation, but it was impossible to be near the operating installation. The research team consisted of six people. Five of them soon died between the ages of forty-five and fifty-five, and the sixth became disabled. Death came completely different reasons after some time (within about seven to eight years). Nevertheless, at the Energoniva installation, the followers of the third generation and Vachaev's student carried out experiments and made the assumption that a low-energy nuclear reaction took place in the experiments of the deceased scientist.

I. S. Filimonenko

Cold thermonuclear fusion was studied in the USSR already in the late fifties of the last century. The reactor was designed by Ivan Stepanovich Filimonenko. However, no one managed to understand the principles of operation of this unit. That is why, instead of the position of an undisputed leader in the field of nuclear energy technologies, our country has taken the place of a raw materials appendage that sells its own natural resources, depriving entire generations of the future. But the pilot plant had already been created, and it produced a warm fusion reaction. The author of the most breakthrough energy structures that suppress radiation was a native of the Irkutsk region, who went through the entire war from his sixteen to twenty years as a scout, an order bearer, an energetic and talented physicist I.S. Filimonenko.

Thermonuclear fusion cold type was, as never before, close. Warm fusion took place at a temperature of only 1150 degrees Celsius, and heavy water was the basis. Filimonenko was denied a patent: supposedly a nuclear reaction is impossible at such a low temperature. But the synthesis was on! Heavy water was decomposed by electrolysis into deuterium and oxygen, deuterium was dissolved in the palladium of the cathode, where the nuclear fusion reaction took place. The production is waste-free, that is, without radiation, and neutron radiation was also absent. Only in 1957, having enlisted the support of academicians Keldysh, Kurchatov and Korolev, whose authority was indisputable, Filimonenko managed to get things off the ground.

Decay

In 1960, in connection with a secret decree of the Council of Ministers of the USSR and the Central Committee of the CPSU, work began on the invention of Filimonenko under the control of the Ministry of Defense. During the experiments, the researcher found that during the operation of the reactor, some kind of radiation appears, which reduces the half-life of isotopes very quickly. It took half a century to understand the nature of this radiation. Now we know what it is - neutronium with dineutronium. And then, in 1968, the work practically stopped. Filimonenko was accused of political disloyalty.

In 1989, the scientist was rehabilitated. His installations began to be recreated in the NPO Luch. But the matter did not go further than the experiments - they did not have time. The country perished, and the new Russian had no time for fundamental science. One of the best engineers of the twentieth century died in 2013 without seeing the happiness of mankind. The world will remember Ivan Stepanovich Filimonenko. Cold thermonuclear fusion will someday be established by his followers.

(UTS) - the process of fusion of light atomic nuclei, taking place with the release of energy at high temp-pax under controlled controlled conditions. TTS has not yet been implemented. To carry out fusion reactions, the reacting nuclei must be brought together at a distance of about 10 -11 cm, after which the process of their fusion occurs with a noticeable probability due to tunnel effect. To overcome the potential barrier to colliding light nuclei should be reported ~ 10 keV, which corresponds to a temperature of ~ 10 8 K. With an increase in the charge of the nuclei ( serial number Z) their Coulomb repulsion increases and the amount of energy required for the reaction increases. Eff. cross sections of (p, p)-reactions due to weak interactions, very small. Reactions between heavy isotopes of hydrogen (deuterium and tritium) are due to strong interaction and have 22–23 orders of magnitude higher (see Fig. thermonuclear reactions). Differences in the values ​​of energy release in fusion reactions do not exceed one order of magnitude. With the fusion of deuterium and tritium nuclei, it is 17.6 MeV. The large number of these reactions and the relatively high energy release make an equal-component mixture of deuterium and tritium the most promising for solving the problem of controlled fusion. Tritium is radioactive ( half life 12.5 years), does not occur in nature. Therefore, to ensure the work thermonuclear reactor, used as nuclear fuel, the possibility of its reproduction should be provided. To this end work zone the reactor can be surrounded by a layer of a light isotope of lithium, in which the reaction will take place

Eff. cross section of thermonuclear reactions increases rapidly with temperature, but even in the optimum. conditions remains incomparably less eff. cross sections of atomic collisions. For this reason, fusion reactions must take place in a fully ionized plasma heated to a high temperature, where ionization and excitation of atoms are absent and deuteron-deuteron or deuton-triton collisions sooner or later end in nuclear fusion.

Successful operation and further development of any of the listed systems is possible only if the initial structure is macroscopically stable, retaining the given shape during the entire time required for the reaction to proceed. In addition, in the plasma, those microscopic ones must be suppressed. instability, in the event of the emergence and development of which particles in energy cease to be equilibrium and the flows of particles and heat across lines of force increase sharply compared with their theoretical. value. Precisely in the direction of stabilization of plasma instabilities different type developed the main magnetic research. systems since 1952, and this work cannot be considered complete yet.

Ultra-fast control systems with inertial confinement. Difficulties associated with magnet. Plasma confinement can, in principle, be circumvented by "burning" thermonuclear fuel in extremely short times, when the heated fuel does not have time to scatter from the reaction zone. According to the Lawson criterion, the implementation of CTS with this method of combustion can be achieved only at a very high density of the working substance. To avoid the situation of a high-power thermonuclear explosion, it is necessary to use very small portions of fuel: the initial thermonuclear fuel must be in the form of small grains (several mm in diameter) prepared from a mixture of solid deuterium and tritium, injected into the reactor before each of its working cycles. Ch. the problem lies in the rapid supply of the necessary energy to heat the grains of fuel. The solution to this problem lies in the use laser radiation(cm. Laser fusion) or intense focused beams of fast charge. particles. Research in the field of CTS using laser heating began in 1964; The use of beams of heavy and light ions is at an even earlier stage of study (see Ref. Ionic thermonuclear fusion).

Energy W, which must be brought to a grain of fuel to ensure the operation of the installation in the reactor mode, as follows from a simple calculation, is inversely proportional to the square of the density of deuterium-tritium fuel. Estimates show that admissible values W are obtained only in the case of a sharp, 10 2 -10 3 times, increase in the density of thermonuclear fuel compared to the initial density of the solid (d, t) target. Such high compression ratios, necessary to obtain such high densities, turn out to be achievable by evaporation of the surface layers of a symmetrically irradiated target and reactive compression of its internal. zones. To do this, the input power must be programmed in a certain way in time. Dr. The possibilities lie in programming the radial distribution of matter density and in the use of complex multi-shell targets. The required energy is estimated at ~10 6 -10 7 J, which lies within the current. possibilities of laser technology. An analysis of systems with ion beams leads to figures of the same scale.

Difficulties and prospects. Research in the field of CTS faces great difficulties, both purely physical and technical. character. The already mentioned problem of the stability of a hot plasma placed in a magnetic field belongs to the former. trap. The use of strong magnets special fields configuration allowed to suppress many. types of macroscopic instabilities, but will end. the issue is still not resolved.

In particular, for an interesting and important system - the tokamak - the so-called. the problem of "big disruption", in which the plasma current cord is first drawn to the axis of the chamber, then interrupted for several. ms and a lot of energy is discharged onto the chamber walls. In addition to thermal shock, the chamber also experiences mechanical shock. .

A serious difficulty is also the formation of beams of fast electrons detached from the main. ensemble of plasma electrons. These beams lead to a strong increase in heat and particle fluxes across the field. In ultrafast systems, the formation of a group of fast electrons in the plasma corona surrounding the target is also observed. These electrons have time to prematurely heat the central zones of the target, preventing the achievement of the required degree of compression and the subsequent programmed occurrence of nuclear reactions. Main The difficulty in these systems is the implementation of stable spherically symmetric compression of targets.

Another difficulty is related to the problem of impurities. El.-mag. at the values ​​used P and T plasma and possible sizes reactor freely leaves the plasma, but for a purely hydrogen plasma, these energetic. losses determined in the main. bremsstrahlung of electrons, in the case of (d, 1)-reactions, they are overlapped by nuclear energy release even at temperatures above 4-10 7 K. However, even a small addition of foreign atoms with large Z, which at the considered temperatures are in a strongly ionized state, lead to an increase in energy. losses are above the acceptable level. Extraordinary efforts are required (continuous improvement of vacuum installations, the use of refractory and difficult-to-disperse substances, such as tungsten, as a diaphragm material, the use of devices for trapping impurity atoms, etc.) to keep the content of impurities in the plasma below the permissible level (=<0,1%). Для инер-циальных систем-предотвращение перемешивания вещества сжимающей оболочки с термоядерным топливом на конечных стадиях сжатия.

On fig. 3 shows the parameters achieved at decomp. installations by 1994. As can be seen, the parameters of these systems are close to the threshold values. Moreover, on the largest operating tokamak JET (West Europe) in November 1991, a discharge on (d, 1)-plasma with a duration of approx. 2 s. In this case, the fusion energy was obtained under controlled conditions at a power level of ~ 1 MW. A year later, ~6 MW energy was obtained at the TFTR facility. From ecological For reasons of consideration, the experiments were carried out not on an equal-component mixture of deuterium and tritium, but with a tritium content of 10-11%. In the TFTR experiment, the ratio of fusion energy to cost. energy was 0.15 (in terms of an equal-component mixture ~0.46). The success of these experiments has clearly put forward a leading position among the installations being developed under the UTS program. In connection with the foregoing, it is clear that in the international ITER project, which is supposed to be implemented by 2003 and which should serve as an experiment. model of a future power plant with a fusion reactor, it is proposed to use the tokamak system.

Rice. 3. Parameters achieved at various facilities for studying the problem of controlled thermonuclear fusion by 1991. T-10 tokamak facility of the IV Kurchatov Institute of Atomic Energy (USSR); PLT tokamak facility at Princeton Laboratory (USA); Alkator - tokamak installation of the Massachusetts Institute of Technology (USA); TFR - tokamak plant in Fontenay-aux-Rose (France); 2 HPV - open trap of the Livermore Laboratory (USA); "Shiva" (Livermore Laboratory, USA); "Downpour" (FIAN, Moscow); stellarator "Wendelstein UP" (Garching, Germany).

However, it should be clearly understood that the path from a working reactor to an operating power plant is still very long. Radiation the activation of the walls of the reactor chamber when operating on fuel containing tritium is extremely high. Even if it is possible to carry out stationary operation of the reactor for a period of time, mechanical. resistance of the first wall of the chamber as a result of radiation. damage is unlikely to exceed (according to experts) 5-6 years. This means the need for periodic complete dismantling of the installation and subsequent reassembly with the help of remotely operating robots, since the residual will be measured in thousands of megacuries. Deep underground burial of huge parts of the installation will also be inevitable.

A beautiful possibility of a sharp reduction in the radioactivity of the operating system and the residual induced activity can be achieved when operating on fuel with the isotope 3 He. According to the reaction, the energy release remains at the same level, the formation of neutrons will occur only due to side (d, d) reactions. Unfortunately, the necessary isotope 3 would not have to be brought from the surface of the Moon, where it is present in concentrations, while on Earth its content is negligible.

If we talk about long-term forecasts, then the optimum should probably be sought in a combination of solar energy and CTS. For the possibilities associated with exceptionally interesting, but even more distant prospects for using the process of muon catalysis for the implementation of CTS, see Art. Muont catalysis.

Lit.: Artsimovich L. A., Managed, 2nd ed., M., 1963; Furth, H. P., Tokamak research, "Nucl. Fus.", 1975, v. 15, no. 3, p. 487; Lukyanov. Yu., Hot Plasma and Controlled Nuclear Fusion, Moscow, 1975; Problems of laser thermonuclear fusion. Sat. Art., M., 1976; Results of science and technology, ser. Plasma Physics, vol. 1-3, M., 1980-82. FROM. Y. Lukyanov.

Physical encyclopedia. In 5 volumes. - M.: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1988 .

See what "CONTROLLED FUSION" is in other dictionaries:

- (UTS), the process of fusion of light atomic nuclei, taking place with the release of energy, at high temperatures under controlled, controlled conditions. TTS has not yet been implemented. To carry out fusion reactions, the reacting nuclei must be brought together by ... ... Physical Encyclopedia

- (UTS), the fusion of light atomic nuclei (for example, deuterium and tritium) with the release of energy, occurring at very high temperatures (? 108K) under controlled conditions (in a thermonuclear reactor). The possibility of implementing the TCB is theoretically calculated in ... ... Modern Encyclopedia

- (UTS) the scientific problem of the implementation of the synthesis of light nuclei in order to produce energy. The solution to the problem will be achieved in plasma at a temperature of T 108K and fulfillment of the Lawson criterion (n? 1014 cm 3.s, where n is the density of high-temperature plasma; ?… … Big Encyclopedic Dictionary

controlled thermonuclear fusion- - [A.S. Goldberg. English Russian Energy Dictionary. 2006] Energy topics in general EN controlled thermonuclear fusioncontrolled nuclear fusionCTF … Technical Translator's Handbook

Controlled thermonuclear fusion- (UTS), the fusion of light atomic nuclei (for example, deuterium and tritium) with the release of energy, occurring at very high temperatures (³108K) under controlled conditions (in a thermonuclear reactor). The possibility of implementing the TCB is theoretically calculated in ... ... Illustrated Encyclopedic Dictionary

The sun is a natural thermonuclear reactor Controlled thermonuclear fusion (CTF) is the synthesis of heavier atomic nuclei from lighter ones in order to obtain energy, which, unlike explosive thermonuclear fusion (and ... Wikipedia

The process of fusion of light atomic nuclei, which occurs with the release of energy at high temperatures under controlled, controlled conditions. The rates of thermonuclear reactions are low due to the Coulomb repulsion (see Coulomb law) ... ... Great Soviet Encyclopedia

Controlled thermonuclear fusion- controlled flow of fusion of light nuclei (deuterium, tritium nuclei) into helium nuclei for the purpose of energy production (uncontrolled synthesis is carried out in a hydrogen bomb). There is no technical solution yet... Beginnings of modern natural science, Rozhansky V.A. The textbook contains a presentation of the issues of kinetics, dynamics and equilibrium of plasma, as well as transfer processes in it. This course differs from most courses on plasma physics in that…

Shikanov A.S. // Soros Educational Journal, No. 8, 1997, pp: 86-91

We will look at the physical principles of laser fusion, a rapidly developing scientific field based on two outstanding discoveries of the 20th century: thermonuclear reactions and lasers.

Thermonuclear reactions proceed during the fusion (synthesis) of the nuclei of light elements. In this case, along with the formation of heavier elements, excess energy is released in the form of the kinetic energy of the final reaction products and gamma radiation. The large energy release during the course of thermonuclear reactions attracts the attention of scientists because of the possibility of their practical application in terrestrial conditions. Thus, thermonuclear reactions on a large scale were carried out in a hydrogen (or thermonuclear) bomb.

Extremely attractive is the possibility of utilizing the energy released during thermonuclear reactions to solve the energy problem. The fact is that the fuel for this method of obtaining energy is the hydrogen isotope deuterium (D), the reserves of which in the oceans are practically inexhaustible.

Fusion Reactions and Controlled Fusion

A thermonuclear reaction is the process of fusion (or fusion) of light nuclei into heavier ones. Since in this case the formation of strongly bound nuclei from looser ones occurs, the process is accompanied by the release of binding energy. The easiest way is the fusion of hydrogen isotopes - deuterium D and tritium T. The deuterium nucleus - deuteron contains one proton and one neutron. Deuterium is found in water at a ratio of one part to 6500 parts of hydrogen. The nucleus of tritium, the triton, consists of a proton and two neutrons. Tritium is unstable (half-life 12.4 years), but can be obtained as a result of nuclear reactions.

During the fusion of deuterium and tritium nuclei, helium He with an atomic mass of four and a neutron n are formed. As a result of the reaction, an energy of 17.6 MeV is released.

The fusion of deuterium nuclei occurs along two channels with approximately the same probability: in the first one, tritium and a proton p are formed and an energy equal to 4 MeV is released; in the second channel - helium with an atomic mass of 3 and a neutron, and the released energy is 3.25 MeV. These reactions are presented in the form of formulas

D + T = 4He + n + 17.6 MeV,

D + D = T + p + 4.0 MeV,

D + D = 3He + n + 3.25 MeV.

Before the fusion process, the nuclei of deuterium and tritium have an energy of the order of 10 keV; the energy of the reaction products reaches values ​​on the order of units and tens of megaelectronvolts. It should also be noted that the cross section of the D + T reaction and the rate of its occurrence are much higher (hundreds of times) than for the D + D reaction. Therefore, it is much easier for the D + T reaction to achieve conditions when the released thermonuclear energy exceeds the costs of organizing processes mergers.

Synthesis reactions involving other nuclei of elements (for example, lithium, boron, etc.) are also possible. However, the reaction cross sections and their rates for these elements are much smaller than for hydrogen isotopes, and reach appreciable values ​​only for temperatures of the order of 100 keV. Achieving such temperatures in thermonuclear installations is currently completely unrealistic, so only fusion reactions of hydrogen isotopes can be of practical use in the near future.

How can a thermonuclear reaction be carried out? The problem is that the fusion of the nuclei is prevented by the electric forces of repulsion. In accordance with the Coulomb law, the electric repulsion force grows inversely proportional to the square of the distance between the interacting nuclei F ~ 1/ r 2. Therefore, for the fusion of nuclei, the formation of new elements and the release of excess energy, it is necessary to overcome the Coulomb barrier, that is, to perform work against the repulsion forces, informing the nuclei the necessary energy.

There are two possibilities. One of them consists in the collision of two beams of light atoms accelerated towards each other. However, this approach turned out to be inefficient. The fact is that the probability of nuclear fusion in accelerated beams is extremely small due to the low density of nuclei and the negligible time of their interaction, although the creation of beams of the required energy in existing accelerators is not a problem.

Another way, on which modern researchers have stopped, is heating the substance to high temperatures (about 100 million degrees). The higher the temperature, the higher the average kinetic energy of the particles and the greater their number can overcome the Coulomb barrier.

To quantify the efficiency of thermonuclear reactions, the energy gain factor Q is introduced, which is equal to

where Eout is the energy released as a result of fusion reactions, Eset is the energy used to heat the plasma to thermonuclear temperatures.

In order for the energy released as a result of the reaction to be equal to the energy costs for heating the plasma to temperatures of the order of 10 keV, the so-called Lawson criterion must be satisfied:

(Nt) $ 1014 s/cm3 for D-T reaction,

(Nt) $ 1015 s/cm3 for D-D reaction.

Here N is the density of the deuterium-tritium mixture (the number of particles in a cubic centimeter), t is the time of effective fusion reactions.

To date, two largely independent approaches to solving the problem of controlled thermonuclear fusion have been formed. The first of them is based on the possibility of confining and thermally insulating a high-temperature plasma of relatively low density (N © 1014-1015 cm-3) by a magnetic field of a special configuration for a relatively long time (t © 1-10 s). Such systems include "Tokamak" (short for "toroidal chamber with magnetic coils"), proposed in the 50s in the USSR.

The other way is impulse. In the pulsed approach, it is necessary to quickly heat and compress small portions of matter to such temperatures and densities at which thermonuclear reactions would have time to efficiently proceed during the existence of an uncontained or, as they say, inertially confined plasma. Estimates show that in order to compress matter to densities of 100-1000 g/cm3 and heat it to a temperature T © 5-10 keV, it is necessary to create pressure on the surface of the spherical target P © 5 » 109 atm, that is, a source is needed that would allow energy to be delivered to the target surface with a power density q © 1015 W/cm2.

PHYSICAL PRINCIPLES OF LASER FUSION

The idea of ​​using high-power laser radiation for heating dense plasma to thermonuclear temperatures was first proposed by N.G. Basov and O.N. Krokhin in the early 1960s. To date, an independent area of ​​thermonuclear research has been formed - laser thermonuclear fusion (LTF).

Let us dwell briefly on the basic physical principles underlying the concept of achieving high degrees of compression of substances and obtaining high energy gains with the help of laser microexplosions. Consideration will be built on the example of the so-called direct compression mode. In this mode, a microsphere (Fig. 1) filled with thermonuclear fuel is “uniformly” irradiated from all sides by a multichannel laser. As a result of the interaction of heating radiation with the target surface, a hot plasma with a temperature of several kiloelectronvolts (the so-called plasma corona) is formed, which expands towards the laser beam with characteristic velocities of 107–108 cm/s.

Without being able to dwell on absorption processes in the plasma corona in more detail, we note that in modern model experiments at laser radiation energies of 10–100 kJ for targets comparable in size to targets for high gains, it is possible to achieve high (© 90%) coefficients of absorption of heating radiation.

As we have already seen, light radiation cannot penetrate into the dense layers of the target (the density of a solid is 1023 cm-3). Due to thermal conductivity, the energy absorbed in plasma with an electron density lower than ncr is transferred to denser layers, where the target substance is ablated. The remaining unevaporated layers of the target accelerate towards the center under the action of thermal and jet pressure, compressing and heating the fuel contained in it (Fig. 2). As a result, the laser radiation energy is converted at the stage under consideration into the kinetic energy of the matter flying towards the center and into the energy of the expanding corona. It is obvious that the useful energy is concentrated in the movement towards the center. The efficiency of the contribution of light energy to the target is characterized by the ratio of the indicated energy to the total radiation energy, the so-called hydrodynamic efficiency factor (COP). Achieving a sufficiently high hydrodynamic efficiency (10-20%) is one of the important problems of laser thermonuclear fusion.

Rice. 2. Radial distribution of the temperature and density of matter in the target at the stage of shell acceleration to the center

What processes can hinder the achievement of high compression ratios? One of them is that at thermonuclear radiation densities q > 1014 W/cm2, a significant fraction of the absorbed energy is transformed not into a classical electron heat conduction wave, but into fast electron flows, the energy of which is much higher than the plasma corona temperature (the so-called epithermal electrons). This can occur both due to resonant absorption and due to parametric effects in the plasma corona. In this case, the path length of epithermal electrons may turn out to be comparable with the dimensions of the target, which will lead to preliminary heating of the compressible fuel and the impossibility of obtaining limiting compressions. X-ray quanta of high energy (hard X-ray radiation), accompanying epithermal electrons, also have a large penetrating power.

The trend of experimental research recent years is the transition to the use of short-wavelength laser radiation (l< 0,5 мкм) при умеренных плотностях потока (q < 1015 Вт/см2). Практическая возможность перехода к нагреву плазмы коротковолновым излучением связана с тем, что коэффициенты конверсии излучения твердотельного неодимого лазера (основного кандидата в драйверы для лазерного термоядерного синтеза) с длиной волны l = 1,06 мкм в излучения второй, третьей и четвертой гармоник с помощью нелинейных кристаллов достигает 70-80%. В настоящее время фактически все крупные лазерные установки на неодимовом стекле снабжены системами умножения частоты. Физической причиной преимущества использования коротковолнового излучения для нагрева и сжатия микросфер является то, что с уменьшением длины волны увеличивается поглощение в плазменной короне и возрастают абляционное давление и гидродинамический коэффициент передачи. На несколько порядков уменьшается доля надтепловых электронов, генерируемых в плазменной короне, что является чрезвычайно выгодным для режимов как прямого, так и непрямого сжатия. Для непрямого сжатия принципиально и то, что с уменьшением длины волны увеличивается конверсия поглощенной плазмой энергии в мягкое рентгеновское излучение. Остановимся теперь на режиме непрямого сжатия. Физический анализ показывает, что осуществление режима сжатия до высоких плотностей топлива оптимально для простых и сложных оболочечных мишеней с аспектным отношением R / DR в несколько десятков. Здесь R — радиус оболочки, DR — ее толщина. Однако сильное сжатие может быть ограничено развитием гидродинамических неустойчивостей, которые проявляются в отклонении движения оболочки на стадиях ее ускорения и торможения в центре от сферической симметрии и зависят от отклонений начальной формы мишени от идеально сферической, неоднородного распределения падающих лазерных лучей по ее поверхности. Развитие неустойчивости при движении оболочки к центру приводит сначала к отклонению движения от сферически-симметричного, затем к турбулизации течения и в конце концов к перемешиванию слоев мишени и дейтериево-тритиевого горючего. В результате в конечном состоянии может возникнуть образование, форма которого резко отличается от сферического ядра, а средние плотность и температура значительно ниже величин, соответствующих одномерному сжатию. При этом начальная структура мишени (например, определенный набор слоев) может быть полностью нарушена. physical nature this type of instability is equivalent to the instability of a layer of mercury located on the water surface in the gravitational field. In this case, as is known, there is a complete mixing of mercury and water, that is, in the final state, mercury will be at the bottom. A similar situation can occur when a target with a complex structure moves rapidly towards the center of the substance, or in the general case in the presence of density and pressure gradients. The requirements for the quality of targets are quite strict. Thus, the inhomogeneity of the microsphere wall thickness should not exceed 1%, the uniformity of the energy absorption distribution over the target surface should not exceed 0.5%. The proposal to use the scheme of indirect compression is just related to the possibility of solving the problem of stability of target compression. circuit diagram experiment in the indirect compression mode is shown in fig. 3. Laser radiation is introduced into the cavity (hohlraum), focusing on the inner surface of the outer shell, consisting of a substance with a high atomic number, such as gold. As already noted, up to 80% of the absorbed energy is transformed into soft X-ray radiation, which heats and compresses the inner shell. The advantages of such a scheme include the possibility of achieving a higher uniformity of the absorbed energy distribution over the target surface, simplification of the laser scheme and focusing conditions, etc. However, there are also disadvantages associated with the loss of energy for conversion into X-rays and the complexity of introducing radiation into the cavity. What is the current state of research on laser fusion? Experiments to achieve high densities of compressible fuel in the direct compression mode began in the mid-1970s in Physics Institute them. P.N. Lebedev, where the density of compressible deuterium © 10 g/cm3 was achieved on the Kalmar facility with energy E = 200 J. Subsequently, work programs on LTS were actively developed in the USA (Shiva and Nova facilities at the Livermore National Laboratory, Omega at the University of Rochester), Japan (Gekko-12), Russia (Dolphin at FIAN, Iskra-4", "Iskra-5" in Arzamas-16) at the laser energy level of 1-100 kJ. All aspects of heating and compression of targets of various configurations in direct and indirect compression modes are studied in detail. An ablation pressure of ~100 Mbar and a microsphere collapse velocity of V > 200 km/s are achieved at hydrodynamic efficiency values ​​of about 10%. Progress in the development of laser systems and target structures has made it possible to ensure a degree of uniformity of irradiation of a compressible shell of 1–2% both under direct and indirect compression. In both regimes, compressed gas densities of 20–40 g/cm3 were achieved, and the compressed shell density of 600 g/cm3 was recorded at the Gekko-12 facility. Maximum neutron yield N = 1014 neutrons per burst.

CONCLUSION

Thus, the totality of the obtained experimental results and their analysis point to the practical feasibility of the next stage in the development of laser thermonuclear fusion—the achievement of deuterium-tritium gas densities of 200–300 g/cm 1 MJ (see Fig. 4 and ).

At present, the element base is being intensively developed and projects are being created for megajoule-level laser installations. At the Livermore Laboratory, the creation of an installation on neodymium glass with an energy of E = 1.8 MJ has begun. The cost of the project is $2 billion. The creation of an installation of a similar level is planned in France. It is planned to achieve an energy gain Q ~ 100 at this facility. It must be said that the launch of facilities of this scale will not only bring the possibility of creating a thermonuclear reactor based on laser fusion, but will also provide researchers with a unique physical object - a microexplosion with energy release 107-109 J, a powerful source of neutron, neutrino, x-ray and g-radiation. This will not only be of great general physical importance (the ability to study substances in extreme states, the physics of combustion, the equation of state, laser effects, etc.), but will also make it possible to solve special problems of an applied, including military, nature.

For a reactor based on laser fusion, however, it is necessary to create a megajoule-level laser operating at a repetition rate of several hertz. A number of laboratories are investigating the possibility of creating such systems based on new crystals. The launch of an experimental reactor under the American program is planned for 2025.

Innovative projects using modern superconductors will soon allow controlled thermonuclear fusion, some optimists say. Experts, however, predict that practical application will take several decades.

Why is it so difficult?

Fusion energy is considered a potential source. It is the pure energy of an atom. But what is it and why is it so difficult to achieve? First you need to understand the difference between classical and thermonuclear fusion.

The fission of the atom consists in the fact that radioactive isotopes - uranium or plutonium - are split and converted into other highly radioactive isotopes, which then must be buried or recycled.

Synthesis consists in the fact that two isotopes of hydrogen - deuterium and tritium - merge into a single whole, forming non-toxic helium and a single neutron, without producing radioactive waste.

Control problem

The reactions that take place on the Sun or in a hydrogen bomb are thermonuclear fusion, and engineers face a daunting task - how to control this process at a power plant?

This is something scientists have been working on since the 1960s. Another experimental fusion reactor called Wendelstein 7-X has started operation in the northern German city of Greifswald. It is not yet designed to create a reaction - it is just a special design that is being tested (a stellarator instead of a tokamak).

high energy plasma

All thermonuclear plants have common feature- ring-shaped. It is based on the idea of ​​using powerful electromagnets to create a strong electromagnetic field, which has the shape of a torus - an inflated bicycle chamber.

This electromagnetic field must be so dense that when it is heated in a microwave oven to one million degrees Celsius, a plasma must appear in the very center of the ring. It is then ignited so that thermonuclear fusion can begin.

Demonstration of possibilities

Two such experiments are currently underway in Europe. One of them is the Wendelstein 7-X, which recently generated its first helium plasma. The other is ITER, a huge experimental fusion facility in the south of France that is still under construction and will be ready to go live in 2023.

Real nuclear reactions are expected to take place at ITER, albeit only for a short period of time and certainly no longer than 60 minutes. This reactor is just one of many steps on the way to making nuclear fusion a reality.

Fusion reactor: smaller and more powerful

Recently, several designers have announced a new reactor design. According to a group of students from the Massachusetts Institute of Technology, as well as representatives of the weapons company Lockheed Martin, fusion can be carried out in facilities that are much more powerful and smaller than ITER, and they are ready to do it within ten years.

The idea of ​​the new design is to use modern high-temperature superconductors in electromagnets, which exhibit their properties when cooled with liquid nitrogen, and not conventional ones, which require a new, more flexible technology will completely change the design of the reactor.

Klaus Hesch, who is in charge of technology at the Karlsruhe Institute of Technology in southwestern Germany, is skeptical. It supports the use of new high-temperature superconductors for new reactor designs. But, according to him, to develop something on a computer, taking into account the laws of physics, is not enough. It is necessary to take into account the challenges that arise when putting an idea into practice.

Science fiction

According to Hesh, the MIT student model only shows the possibility of a project. But it's actually a lot of science fiction. The project assumes that serious technical problems of thermonuclear fusion are solved. But modern science has no idea how to solve them.

One such problem is the idea of ​​collapsible coils. Electromagnets can be dismantled in order to get inside the ring that holds the plasma in the MIT design model.

This would be very useful because one would be able to access objects during internal system and replace them. But in reality, superconductors are made of ceramic material. Hundreds of them must be intertwined in a sophisticated way to form the correct magnetic field. And here there are more fundamental difficulties: the connections between them are not as simple as the connections of copper cables. No one has even thought of concepts that would help solve such problems.

too hot

High temperature is also a problem. At the core of the fusion plasma, the temperature will reach about 150 million degrees Celsius. This extreme heat remains in place - right in the center of the ionized gas. But even around it it is still very hot - from 500 to 700 degrees in the reactor zone, which is the inner layer of a metal pipe in which the tritium necessary for nuclear fusion to occur will "reproduce".

It has an even bigger problem - the so-called power release. This is the part of the system that receives used fuel from the fusion process, mainly helium. The first metal components that the hot gas enters are called the "divertor". It can heat up to over 2000°C.

Diverter problem

In order for the installation to withstand such temperatures, engineers are trying to use the metal tungsten used in old-fashioned incandescent lamps. The melting point of tungsten is about 3000 degrees. But there are other limitations as well.

In ITER, this can be done, because heating in it does not occur constantly. It is assumed that the reactor will operate only 1-3% of the time. But that's not an option for a power plant that needs to run 24/7. And, if someone claims to be able to build a smaller reactor with the same power as ITER, it is safe to say that he does not have a solution to the divertor problem.

Power plant in a few decades

Nevertheless, scientists are optimistic about the development fusion reactors, however, it will not be as fast as some enthusiasts predict.

ITER should show that controlled fusion can actually produce more energy than would be spent on heating the plasma. The next step is to build a brand new hybrid demonstration power plant that actually generates electricity.

Engineers are already working on its design. They will have to learn from ITER, which is scheduled to launch in 2023. Given the time required for design, planning and construction, it seems unlikely that the first fusion power plant will be launched much earlier than the middle of the 21st century.

Cold Fusion Rossi

In 2014, an independent test of the E-Cat reactor concluded that the device averaged 2,800 watts of power output over a 32-day period with a consumption of 900 watts. This is more than any chemical reaction is capable of isolating. The result speaks either of a breakthrough in thermonuclear fusion, or of outright fraud. The report disappointed skeptics, who doubt whether the test was truly independent and suggest possible falsification of the test results. Others have been busy figuring out the "secret ingredients" that enable Rossi's fusion to replicate the technology.

Rossi is a scammer?

Andrea is imposing. He publishes proclamations to the world in unique English in the comments section of his website, pretentiously called the Journal of Nuclear Physics. But his previous failed attempts have included an Italian waste-to-fuel project and a thermoelectric generator. Petroldragon, a waste-to-energy project, failed in part because the illegal dumping of waste is controlled by Italian organized crime, which has filed criminal charges against it for violating waste management regulations. He also created a thermoelectric device for the Corps of Engineers ground forces USA, but during testing, the gadget produced only a fraction of the declared power.

Many do not trust Rossi, and the editor-in-chief of the New Energy Times bluntly called him a criminal with a string of failed energy projects behind him.

Independent Verification

Rossi signed a contract with American company Industrial Heat to conduct a year-long secret test of a 1-MW cold fusion plant. The device was a shipping container packed with dozens of E-Cats. The experiment had to be controlled by a third party who could confirm that heat generation was indeed taking place. Rossi claims to have spent most last year, practically living in a container, and oversaw operations for more than 16 hours a day to prove the commercial viability of the E-Cat.

The test ended in March. Rossi's supporters eagerly awaited the observers' report, hoping for an acquittal for their hero. But in the end they got sued.

Trial

In a Florida court filing, Rossi claims the test was successful and an independent arbitrator confirmed that the E-Cat reactor produces six times more energy than it consumes. He also claimed that Industrial Heat agreed to pay him $100 million - $11.5 million upfront after the 24-hour trial (ostensibly for licensing rights so the company could sell the technology in the US) and another $89 million after the successful completion of the extended trial. within 350 days. Rossi accused IH of running a "fraudulent scheme" to steal his intellectual property. He also accused the company of misappropriation of E-Cat reactors, illegal copying innovative technologies and products functionality and designs and abusive attempts to obtain a patent on his intellectual property.

Goldmine

Elsewhere, Rossi claims that in one of his demonstrations, IH received $50-60 million from investors and another $200 million from China after a replay involving top Chinese officials. If this is true, then a lot more than a hundred million dollars is at stake. Industrial Heat has dismissed these claims as baseless and is going to actively defend itself. More importantly, she claims that she "worked for more than three years to confirm the results that Rossi allegedly achieved with his E-Cat technology, all without success."

IH doesn't believe in the E-Cat, and the New Energy Times sees no reason to doubt it. In June 2011, a representative of the publication visited Italy, interviewed Rossi and filmed a demonstration of his E-Cat. A day later, he reported his serious concerns about the method of measuring thermal power. After 6 days, the journalist posted his video on YouTube. Experts from all over the world sent him analyzes, which were published in July. It became clear that this was a scam.

Experimental confirmation

Nevertheless, a number of researchers - Alexander Parkhomov of the Peoples' Friendship University of Russia and the Martin Fleishman Memorial Project (MFPM) - have succeeded in replicating Russia's cold fusion. The MFPM report was titled "The End of the Carbon Era Is Near". The reason for such admiration was the discovery, which cannot be explained otherwise than by a thermonuclear reaction. According to the researchers, Rossi has exactly what he is talking about.

A viable open recipe for cold fusion could spark an energy gold rush. Alternative methods may be found to bypass Rossi's patents and keep him out of the multi-billion dollar energy business.

So perhaps Rossi would prefer to avoid this confirmation.

thermonuclear fusion, the reaction of fusion of light atomic nuclei into heavier nuclei, occurring at ultrahigh temperature and accompanied by the release huge quantities energy. Nuclear fusion is the reverse reaction of atomic fission: in the latter, energy is released due to the splitting of heavy nuclei into lighter ones. see also NUCLEAR FISSION; NUCLEAR POWER.

According to modern astrophysical concepts, the main source of energy for the Sun and other stars is thermonuclear fusion occurring in their depths. Under terrestrial conditions, it is carried out during the explosion of a hydrogen bomb. Thermonuclear fusion is accompanied by a colossal energy release per unit mass of reacting substances (about 10 million times greater than in chemical reactions). Therefore, it is of great interest to master this process and, on its basis, create a cheap and environmentally friendly source of energy. However, despite the fact that research on controlled thermonuclear fusion (CTF) is carried out by large scientific and technical teams in many developed countries, there are still many difficult problems to be solved before industrial production fusion energy will become a reality.

Modern nuclear power plants using the fission process only partially satisfy the world's electricity needs. The fuel for them is the natural radioactive elements uranium and thorium, the prevalence and reserves of which in nature are very limited; therefore, for many countries there is a problem of their import. The main component of thermonuclear fuel is the hydrogen isotope deuterium, which is found in sea water. Its reserves are publicly available and very large (the world ocean covers ~ 71% of the Earth's surface area, and deuterium accounts for approx. 0.016% total number hydrogen atoms in water). In addition to the availability of fuel, thermonuclear energy sources have the following important advantages over nuclear power plants: 1) the UTS reactor contains much less radioactive materials than a nuclear fission reactor, and therefore the consequences of an accidental release of radioactive products are less dangerous; 2) thermonuclear reactions produce less long-lived radioactive waste; 3) TCB allows direct electricity generation.

Artsimovich L.A. Controlled thermonuclear reactions. M., 1963
Thermal and nuclear power plants(book 1, section 6; book 3, section 8). M., 1989

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