Examples of nuclear energy. The first nuclear reactor - Who invented it? A by-product of the atomic bomb

In nature, nuclear energy is released in stars, and by man it is used mainly in nuclear weapons and nuclear energy, in particular, at nuclear power plants.

Physical foundations

Bond energy

Although the nucleus consists of nucleons, however, the mass of the nucleus is not just the sum of the masses of the nucleons. The energy that holds these nucleons together is observed as the difference in the mass of the nucleus and the masses of its constituent individual nucleons, up to a factor c 2 , which relates mass and energy by the equation E = m ⋅ c 2 . (\displaystyle E=m\cdot c^(2).) Thus, by determining the mass of an atom and the mass of its components, one can determine the average energy per nucleon holding various nuclei together.

It can be seen from the graph that very light nuclei have less binding energy per nucleon than nuclei that are slightly heavier (on the left side of the graph). This is the reason why thermonuclear reactions (that is, the fusion of light nuclei) release energy. Conversely, very heavy nuclei on the right side of the graph have lower binding energies per nucleon than medium-mass nuclei. In this regard, the fission of heavy nuclei is also energetically favorable (that is, it occurs with the release of nuclear energy). It should also be noted that during fusion (on the left side) the mass difference is much larger than during fission (on the right side).

The energy required to completely divide the nucleus into individual nucleons is called binding energy E from the core. Specific binding energy (that is, the binding energy per nucleon, ε = E With / A, where A- the number of nucleons in the nucleus, or mass number), is not the same for different chemical elements and even for isotopes of the same chemical element. The specific binding energy of a nucleon in a nucleus varies on average from 1 MeV for light nuclei (deuterium) up to 8.6 MeV for nuclei of medium mass (with a mass number BUT≈ 100 ). For heavy nuclei ( BUT≈ 200 ), the specific binding energy of a nucleon is less than that of nuclei of average mass, by approximately 1 MeV, so that their transformation into nuclei of average weight (division into 2 parts) is accompanied by the release of energy in an amount of about 1 MeV per nucleon, or about 200 MeV per nucleus. The transformation of light nuclei into heavier nuclei gives an even greater energy gain per nucleon. So, for example, the reaction of the combination of deuterium and tritium nuclei

accompanied by an energy release of 17.6 MeV, i.e. 3.5 MeV per nucleon.

Nuclear fission

The appearance of 2.5 neutrons per fission event allows a chain reaction to occur if at least one of these 2.5 neutrons can produce a new fission of the uranium nucleus. Normally, the emitted neutrons do not immediately fission the uranium nuclei, but must first be slowed down to thermal velocities (2200 m/s at T=300 K). Slowdown is achieved most effectively with the help of surrounding atoms of another element with a small A, such as hydrogen, carbon, etc. of a material called a moderator.

Some other nuclei can also fission by capturing slow neutrons, such as 233U or 239. However, fission by fast neutrons (high energy) of such nuclei as 238 U (it is 140 times more than 235 U) or 232 (it is 400 times more than 235 U in the earth's crust) is also possible.

The elementary theory of fission was created by Niels Bohr and J. Wheeler using the drop model of the nucleus.

Nuclear fission can also be achieved with fast alpha particles, protons, or deuterons. However, these particles, unlike neutrons, must have a high energy to overcome the Coulomb barrier of the nucleus.

Release of nuclear energy

Exothermic nuclear reactions are known to release nuclear energy.

Usually, to obtain nuclear energy, a chain nuclear fission reaction of uranium-235 or plutonium nuclei is used, less often other heavy nuclei (uranium-238, thorium-232). Nuclei are divided when a neutron hits them, and new neutrons and fission fragments are obtained. Fission neutrons and fission fragments have high kinetic energy. As a result of collisions of fragments with other atoms, this kinetic energy is quickly converted into heat.

Another way to release nuclear energy is through thermonuclear fusion. In this case, two nuclei of light elements are combined into one heavy one. In nature, such processes occur on the Sun and in other stars, being the main source of their energy.

Many atomic nuclei are unstable. Over time, some of these nuclei spontaneously transform into other nuclei, releasing energy. This phenomenon is called radioactive decay.

Applications of nuclear energy

Division

At present, of all sources of nuclear energy, the energy released during the fission of heavy nuclei has the greatest practical application. Under the conditions of a shortage of energy resources, nuclear power on fission reactors is considered the most promising in the coming decades. In nuclear power plants, nuclear energy is used to generate heat used to generate electricity and heating. Nuclear power plants solved the problem of ships with an unlimited navigation area (nuclear icebreakers, nuclear submarines, nuclear aircraft carriers).

The energy of nuclear fission of uranium or plutonium is used in nuclear and thermonuclear weapons (as a trigger for a thermonuclear reaction and as a source of additional energy in the fission of nuclei by neutrons arising in thermonuclear reactions).

There were experimental nuclear rocket engines, but they were tested exclusively on Earth and under controlled conditions, due to the danger of radioactive contamination in the event of an accident.

Nuclear power plants in 2012 produced 13% of the world's electricity and 5.7% of the total world energy production. According to a report by the International Atomic Energy Agency (IAEA), as of 2013, there are 436 active nuclear energy(that is, producing recyclable electrical and / or thermal energy) reactors in 31 countries of the world. In addition, at different stages of construction is still 73 energy nuclear reactors in 15 countries. Currently, there are also about 140 active surface ships and submarines in the world, using a total of about 180 reactors. Several nuclear reactors have been used in Soviet and American spacecraft, some of which are still in orbit. In addition, a number of applications use nuclear energy generated in non-reactor sources (for example, in thermoisotope generators). At the same time, the debate about the use of nuclear energy does not stop. Opponents of nuclear energy (in particular, organizations such as Greenpeace) believe that the use of nuclear energy threatens humanity and the environment. Defenders of nuclear energy (IAEA, World Nuclear Association, etc.), in turn, argue that this type of energy reduces greenhouse gas emissions into the atmosphere and, during normal operation, carries significantly fewer risks to the environment than other types of energy generation.

Thermonuclear fusion

Fusion energy is used in the hydrogen bomb. The problem of controlled thermonuclear fusion has not yet been solved, but if this problem is solved, it will become an almost unlimited source of cheap energy.

radioactive decay

The energy released by radioactive decay is used in long-lived heat sources and beta-voltaic cells. Automatic interplanetary station type

At the end of the last century, scientists were surprised to discover that atoms, or rather the nuclei of atoms, fall apart by themselves, emitting rays and heat. They called this phenomenon . And when they calculated, they were even more surprised: 1 g of radium, if it completely decays, can give as much heat as 500 kg of coal give by burning. But it is impossible to use this property - atoms decay so slowly that only half of the heat is released in 2000 years.

It's like a big dam. The dam is closed, and the water flows in a small stream that is of no use.

Now, if the dam were opened, if people learned how to destroy atoms!.. They would receive an endless ocean of energy. But how to do that?

They say that they don’t shoot at a sparrow from a cannon, they need a small pellet. And where to get a pellet to split the nucleus of an atom?

Scientists all over the Earth have been hard at work for several decades. During this time, they learned how it works, and found a "shot" for it. It turned out to be one of the particles that is part of the nucleus - the neutron. It easily penetrates the atom and breaks the nucleus.

And then it turned out that the atoms of the uranium metal, having split, emit new neutrons that destroy neighboring atoms. If you take a piece of uranium, in which many nuclei will simultaneously decay and many new neutrons will be released, the fission process will grow like an avalanche in the mountains. An atomic bomb will explode.

The scheme of the device of a nuclear reactor. Thick black rods are neutron absorbers. In the reactor, the water is heated, and then heats the water in the heat exchanger to a boil. The resulting steam rotates the turbine of the power plant.

Imagine that a large dam has collapsed. The water collected behind it all immediately rushes violently down. The power of the stream is great, but only harm from it, because it sweeps away everything in its path. So it is with the atom: the colossal energy of the explosion can only destroy. And people need atomic energy to build. Now, if the atom gave away its reserves in such portions as we want! No energy needed - closed the damper. It took - (How much do you need?) opened two or three dampers: “Get as much as you asked for!”

And the man curbed the explosion.

Who is the main "worker" at the "nuclear plant"? Neutron. It is he who breaks the uranium nuclei. And if we remove some of the workers from the "factory"? Work will go slower.

This is how an atomic boiler, or a nuclear reactor, works. This is a large well with thick concrete walls (they are needed so that radiation harmful to people does not go outside). The well is filled with graphite, the same material used to make pencil leads. There are holes in the graphite filling where uranium rods are placed. When there are enough of them, the required number of “working” neutrons appears and an atomic reaction begins.

To control it, there are rods of metal in other holes, which captures and absorbs neutrons. This is the "flaps" in the dam.

No energy is needed or there is a danger of an explosion, the shutter-rods are instantly lowered, the neutrons emitted from the uranium nuclei are absorbed, stop working, and the reaction stops.

It is necessary for the reaction to start, the shutter rods are raised, “working” neutrons appear in the reactor again, and the temperature in the boiler rises (How much energy do you need? Get it!).

Nuclear reactors can be placed on nuclear power plants, on nuclear submarines, on a nuclear icebreaker. They, like ordinary steam boilers, obediently turn water into steam, which will rotate the turbines. Five hundred kilograms of atomic fuel - the contents of only ten suitcases - is enough for the Lenin icebreaker to sail all year round. Can you imagine how profitable it is: you don’t need to carry hundreds of tons of fuel with you, you can take a more useful cargo instead; you can not go to the port for refueling for a whole year, especially since in the North this is not always easy to do. Yes, and machines can be put stronger ...

In existing nuclear reactors, energy is obtained by destroying nuclei consisting of a large number of particles (in uranium nuclei, for example, there are more than two hundred of them). And although there is still a lot of such fuel on Earth, but someday it will run out ... Is there a way to get nuclear energy from other substances? And scientists have found!

It turned out that atoms, in the nucleus of which there are only two particles: one proton and one neutron, can also serve as a source of energy. But they don’t give it away when they divide, but when they combine, or, as they say, during synthesis, two nuclei.

Hydrogen atoms for this need to be heated to many millions of degrees. At this temperature, their nuclei begin to move at great speed and, having accelerated, they can overcome the electrical repulsive forces that exist between them. When they get close enough, the nuclear forces of attraction begin to act and the nuclei merge. Thousands of times more heat is released than during nuclear fission.

This method of obtaining energy is called a thermonuclear reaction. These reactions rage in the depths of both distant stars and the nearby Sun, which gives us light and heat. But on Earth, they have so far manifested themselves in the form of a devastating explosion of a hydrogen bomb.

Now scientists are working to make hydrogen nuclei combine gradually. And when we learn how to control thermonuclear reactions, we will be able to take advantage of the unlimited reserves of energy contained in water, which consists of hydrogen and whose reserves are inexhaustible.

The energy contained in atomic nuclei and released during nuclear reactions and radioactive decay.

According to forecasts, organic fuels will be enough to meet the energy needs of mankind for 4-5 decades. Solar energy may become the main source of energy in the future. The transition period requires a source of energy that is practically inexhaustible, cheap, renewable and does not pollute the environment. And although nuclear energy does not fully meet all of these requirements, it is developing rapidly and our hope for solving the global energy crisis is associated with it.

The release of the internal energy of atomic nuclei is possible by the fission of heavy nuclei or the synthesis of light nuclei.

Atom characteristic. An atom of any chemical element consists of a nucleus and electrons revolving around it. The nucleus of an atom is made up of neutrons and protons. The common name for the proton and neutron is the term nucleon. Neutrons have no electrical charge protons are positively charged, electrons - negative. The charge of a proton is equal in modulus to the charge of an electron.

The number of protons of the nucleus Z coincides with its atomic number in the periodic system of Mendeleev. The number of neutrons in a nucleus, with few exceptions, is greater than or equal to the number of protons.

The mass of an atom is concentrated in the nucleus and is determined by the mass of the nucleons. The mass of one proton is equal to the mass of one neutron. The mass of an electron is 1/1836 of the mass of a proton.

As the dimension of the mass of atoms is used atomic mass unit(a.m.u.) equal to 1.66 10 -27 kg. 1 amu approximately equal to the mass of one proton. A characteristic of an atom is the mass number A, equal to the total number of protons and neutrons.

The presence of neutrons allows two atoms to have different masses for the same electric charges of the nucleus. The chemical properties of these two atoms will be the same; such atoms are called isotopes. In the literature, to the left of the designation of the element, the mass number is written at the top, and the number of protons is written below.

The nuclear fuel used in such reactors is isotope of uranium with atomic mass 235. Natural uranium is a mixture of three isotopes: uranium-234 (0.006%), uranium-235 (0.711%) and uranium-238 (99.283%). The uranium-235 isotope has unique properties - as a result of the absorption of a low-energy neutron, a uranium-236 nucleus is obtained, which then splits - is divided into two approximately equal parts, called fission products (fragments). The nucleons of the original nucleus are distributed among the fission fragments, but not all - on average 2-3 neutrons are released. As a result of fission, the mass of the original nucleus is not completely preserved, part of it is converted into energy, mainly into the kinetic energy of fission products and neutrons. The value of this energy for one atom of uranium 235 is about 200 MeV.

The core of a conventional reactor with a capacity of 1000 MW contains about 1 thousand tons of uranium, of which only 3 - 4% is uranium-235. 3 kg of this isotope is consumed daily in the reactor. Thus, to supply the reactor with fuel, 430 kg of uranium concentrate must be processed daily, and this averages 2150 tons of uranium ore.

As a result of the fission reaction, fast neutrons are formed in nuclear fuel. If they interact with neighboring nuclei of the fissile material and, in turn, cause a fission reaction in them, an avalanche-like increase in the number of fission events occurs. This fission reaction is called a nuclear fission chain reaction.

The most effective for the development of a fission chain reaction are neutrons with an energy of less than 0.1 keV. They are called thermal, since their energy is comparable to the average energy of the thermal motion of molecules. For comparison, the energy possessed by neutrons formed during the decay of nuclei is 5 MeV. They are called fast neutrons. To use such neutrons in a chain reaction, their energy must be reduced (slowed down). These functions are performed by the retarder. In moderator substances, fast neutrons are scattered by nuclei, and their energy is converted into the energy of thermal motion of atoms of the moderator substance. Graphite, liquid metals (coolant of the 1st circuit) are most widely used as a moderator.

The rapid development of a chain reaction is accompanied by the release of a large amount of heat and overheating of the reactor. To maintain the stationary mode of the reactor, control rods made of materials that strongly absorb thermal neutrons, such as boron or cadmium, are introduced into the reactor core.

The kinetic energy of the decay products is converted into heat. The heat is absorbed by the coolant circulating in the nuclear reactor and transferred to the heat exchanger (1st closed circuit), where steam is produced (2nd circuit), which rotates the turbine of the turbogenerator. The coolant in the reactor is liquid sodium (1st circuit) and water (2nd circuit).

Uranium-235 is a non-renewable resource and if used entirely in nuclear reactors, it will disappear forever. Therefore, it looks attractive to use the uranium-238 isotope, which occurs in much larger quantities, as the initial fuel. This isotope does not support a chain reaction under the influence of neutrons. But it can absorb fast neutrons, forming uranium-239 in the process. In the nuclei of uranium-239, beta decay begins and neptunium-239 (not found in nature) is formed. This isotope also decays and turns into plutonium-239 (not naturally occurring). Plutonium-239 is even more susceptible to the thermal neutron fission reaction. As a result of the fission reaction in the nuclear fuel plutonium-239, fast neutrons are formed, which, together with uranium, form a new fuel and fission products that release heat in fuel elements (TVELs). As a result, 20-30 times more energy can be obtained from a kilogram of natural uranium than in conventional nuclear reactors using uranium-235.

In modern designs, liquid sodium is used as a coolant. In this case, the reactor can operate at higher temperatures, thereby increasing the thermal efficiency of the power plant. up to 40% .

However, the physical properties of plutonium: toxicity, low critical mass for a spontaneous fission reaction, ignition in an oxygen environment, brittleness and self-heating in the metallic state make it difficult to manufacture, process and handle. Therefore, breeder reactors are still less common than thermal neutron reactors.

4. Nuclear power plants

For peaceful purposes, atomic energy is used in nuclear power plants. The share of nuclear power plants in world electricity production is about 14% .

As an example, consider the principle of obtaining electricity at the Voronezh NPP. A liquid metal coolant with an inlet temperature of 571 K is fed through channels to the reactor core through channels at a pressure of 157 ATM (15.7 MPa), which is heated in the reactor to 595 K. The metal coolant is sent to the steam generator, into which cold water enters, turning into steam with a pressure of 65.3 ATM (6.53 MPa). Steam is supplied to the blades of a steam turbine, which rotates a turbogenerator.

In nuclear reactors, the temperature of the produced steam is significantly lower than in the steam generator of thermal power plants running on organic fuel. As a result, the thermal efficiency of nuclear power plants operating with water as a coolant is only 30%. For comparison, in power plants operating on coal, oil or gas, it reaches 40%.

Nuclear power plants are used in power and heat supply systems for the population, and mini-nuclear power plants on sea vessels (nuclear-powered ships, nuclear submarines) are used to drive propellers).

For military purposes, nuclear energy is used in atomic bombs. The atomic bomb is a special fast neutron reactor , in which a fast uncontrolled chain reaction with a high neutron multiplication factor occurs. There are no moderators in the nuclear reactor of an atomic bomb. The dimensions and weight of the device are therefore small.

The nuclear charge of a uranium-235 bomb is divided into two parts, in each of which a chain reaction is impossible. To carry out the explosion, one of the halves of the charge is fired at the other, and when they are connected, an explosive chain reaction occurs almost instantly. An explosive nuclear reaction releases enormous energy. In this case, a temperature of about one hundred million degrees is reached. There is a colossal increase in pressure and a powerful blast wave is formed.

The first nuclear reactor was launched at the University of Chicago (USA) on December 2, 1942. The first atomic bomb was detonated on July 16, 1945 in New Mexico (Alamogordo). It was a device created on the principle of plutonium fission. The bomb consisted of plutonium surrounded by two layers of chemical explosive with fuses.

The first nuclear power plant, which gave current in 1951, was the EBR-1 nuclear power plant (USA). In the former USSR - Obninsk nuclear power plant (Kaluga region, gave current on June 27, 1954). The first nuclear power plant in the USSR with a fast neutron reactor with a capacity of 12 MW was launched in 1969 in the city of Dimitrovgrad. In 1984, there were 317 nuclear power plants operating in the world with a total capacity of 191 thousand MW, which at that time amounted to 12% (1012 kWh) of world electricity production. As of 1981, the largest nuclear power plant in the world was the Biblis nuclear power plant (Germany), whose thermal power of the reactors was 7800 MW.

thermonuclear reactions are called nuclear reactions of fusion of light nuclei into heavier ones. The element used in nuclear fusion is hydrogen. The main advantage of thermonuclear synthesis is the practically unlimited resources of raw materials that can be extracted from sea water. Hydrogen in one form or another makes up 90% of all matter. The fuel for thermonuclear fusion contained in the world's oceans will last for more than 1 billion years (solar radiation and humanity in the solar system will not last much longer). The raw material for thermonuclear fusion contained in 33 km of ocean water is equivalent in energy content to all resources of solid fuels (there is 40 million times more water on Earth). The energy of deuterium contained in a glass of water is equivalent to burning 300 liters of gasoline.

There are 3 isotopes of hydrogen : their atomic masses are -1.2 (deuterium), 3 (tritium). These isotopes can reproduce such nuclear reactions in which the total mass of the final products of the reaction is less than the total mass of the substances that have entered into the reaction. The difference in masses, as in the case of a fission reaction, is the kinetic energy of the reaction products. On average, a decrease in the mass of a substance participating in a thermonuclear fusion reaction by 1 a.m.u. corresponds to the release of 931 MeV energy:

H 2 + H 2 \u003d H 3 + neutron + 3.2 MeV,

H 2 + H 2 \u003d H 3 + proton + 4.0 MeV,

H 2 + H 3 \u003d He 4 + neutron + 17.6 MeV.

Tritium is practically absent in nature. It can be obtained by the interaction of neutrons with lithium isotopes:

Li 6 + neutron \u003d He 4 + H 3 + 4.8 MeV.

The fusion of nuclei of light elements does not occur naturally (excluding processes in space). In order to force the nuclei to enter into the fusion reaction, high temperatures are required (of the order of 107 -109K). In this case, the gas is an ionized plasma. The problem of confining this plasma is the main obstacle to the use of this method of obtaining energy. The temperature of the order of 10 million degrees is typical for the central part of the Sun. It is thermonuclear reactions that are the source of energy that provides radiation from the Sun and stars.

Currently, theoretical and experimental work is underway to study methods of magnetic and inertial plasma confinement.

The method of using magnetic fields. A magnetic field is created that permeates the channel of the moving plasma. The charged particles that make up the plasma, while moving in a magnetic field, are subjected to forces directed perpendicular to the movement of particles and magnetic field lines. Due to the action of these forces, the particles will move in a spiral along the field lines. The stronger the magnetic field, the denser the plasma flow becomes, thereby isolating itself from the shell walls.

Inertial plasma confinement. Thermonuclear explosions are carried out in the reactor with a frequency of 20 explosions per second. To implement this idea, a thermonuclear fuel particle is heated using focused radiation from 10 lasers to the ignition temperature of the fusion reaction in a time before it has time to fly apart over a noticeable distance due to the thermal motion of atoms (10-9 s).

Thermonuclear fusion is the basis of the hydrogen (thermonuclear) bomb. In such a bomb, a self-sustaining thermonuclear reaction of an explosive nature takes place. The explosive is a mixture of deuterium and tritium. As a source of activation energy (a source of high temperatures), the energy of a nuclear fission bomb is used. The world's first thermonuclear bomb was created in the USSR in 1953.

At the end of the 50s, the USSR began to work on the idea of ​​thermonuclear fusion in TOKAMAK type reactors (a toroidal chamber in a magnetic field of a coil). The principle of operation is as follows: the toroidal chamber is evacuated and filled with a gas mixture of deuterium and tritium. A current of several million amperes is passed through the mixture. In 1-2 seconds, the temperature of the mixture rises to hundreds of thousands of degrees. Plasma is formed in the chamber. Further heating is carried out by injection of neutral deuterium and tritium atoms with an energy of 100 - 200 keV. The plasma temperature rises to tens of millions of degrees and a self-sustaining fusion reaction begins. After 10–20 minutes, heavy elements from the partially evaporating material of the chamber walls will accumulate in the plasma. The plasma cools down, thermonuclear combustion stops. The chamber must be turned off again and cleaned of accumulated impurities. The dimensions of the torus at a thermal power of the reactor of 5000 MW are as follows: Outer radius -10m; inner radius - 2.5 m.

Research to find a way to control thermonuclear reactions, i.e. use of thermonuclear energy for peaceful purposes are developing with great intensity.

In 1991, a joint European facility in the UK for the first time achieved a significant energy release in the course of controlled thermonuclear fusion. The optimal mode was maintained for 2 seconds and was accompanied by the release of energy of the order of 1.7 MW. The maximum temperature was 400 million degrees.

Thermonuclear power generator. When deuterium is used as a thermonuclear fuel, two-thirds of the energy must be released in the form of the kinetic energy of charged particles. By electromagnetic methods, this energy can be converted into electrical energy.

Electricity can be obtained in the stationary mode of operation of the installation and pulsed. In the first case, the ions and electrons resulting from the self-sustaining fusion reaction are retarded by the magnetic field. The ion current is separated from the electronic current by means of a transverse magnetic field. The efficiency of such a system during direct braking will be about 50%, and the rest of the energy will be converted into heat.

Fusion engines (not implemented). Scope: space vehicles. A fully ionized deuterium plasma at 1 billion degrees Celsius is held in a filament by the linear magnetic field of superconductor coils. The working fluid is fed into the chamber through the walls, cooling them, and heats up, flowing around the plasma column. The axial velocity of the outflow of ions at the outlet of the magnetic nozzle is 10,000 km/s.

In 1972, at a meeting of the Club of Rome - an organization that studies the causes and seeks solutions to problems on a planetary scale - a report prepared by scientists E. von Weinzsacker, A. H. Lovins was made and produced the effect of an exploding bomb. According to the data given in the report, the energy sources on the planet - coal, gas, oil and uranium - will last until 2030. To extract coal, from which it will be possible to obtain energy for 1 dollar, it will be necessary to spend energy, costing 99 cents.

Uranium-235, which serves as fuel for nuclear power plants, in nature is not so me: only 5% of the total amount of uranium in the world, 2% of which is in Russia. Therefore, nuclear power plants can only be used for auxiliary purposes. The studies of scientists who tried to obtain energy from plasma on "TOKAMAKs" have remained to this day an expensive exercise. In 2000, there were reports that the European Atomic Community (CERN) and Japan were building the first segment of the TOKAMAK.

Salvation may not be the "peaceful atom" of a nuclear power plant, but the "military" one - the energy of a thermonuclear bomb.

Russian scientists called their invention an explosive combustion boiler (FAC). The principle of operation of the PIC is based on the explosion of an ultra-small thermonuclear bomb in a special sarcophagus - a cauldron. Explosions happen regularly. It is interesting that the pressure on the walls of the boiler during the explosion in the PBC is less than in the cylinders of an ordinary car.

For safe operation of the KVS, the internal diameter of the boiler must be at least 100 meters. Double steel walls and a reinforced concrete shell 30 meters thick will dampen vibrations. Only high-quality steel will be used for its construction as for two modern military battleships. It is planned to build the KVS for 5 years. In 2000, in one of the closed cities of Russia, a project was prepared for the construction of an experimental facility for a "bomb" of 2-4 kilotons of nuclear equivalent. The cost of this FAC is 500 million dollars. Scientists have calculated that it will pay off in a year, and for another 50 years it will provide practically free electricity and heat. According to the project leader, the cost of energy equivalent to that produced by burning a ton of oil will be less than $10.

40 KVGs are able to meet the needs of the entire national energy sector. One hundred - all countries of the Eurasian continent.

In 1932, the positron was experimentally discovered - a particle with the mass of an electron, but with a positive charge. It was soon suggested that charge symmetry exists in nature: a) each particle must have an antiparticle; b) the laws of nature do not change when all particles are replaced by the corresponding antiparticles and vice versa. The antiproton and antineutron were discovered in the mid-1950s. In principle, antimatter can exist, consisting of atoms, the nuclei of which include antiprotons and antineutrons, and their shell is formed by positrons.

Clusters of antimatter of cosmological dimensions would constitute antiworlds, but they are not found in nature. Antimatter has only been synthesized on a laboratory scale. So, in 1969, at the Serpukhov accelerator, Soviet physicists registered antihelium nuclei, consisting of two antiprotons and one antineutron.

In relation to the possibilities of energy conversion, antimatter is remarkable in that when it comes into contact with matter, annihilation (destruction) occurs with the release of colossal energy (both types of matter disappear, turning into radiation). Thus, an electron and a positron, annihilating, give rise to two photons. One type of matter - charged massive particles - passes into another type of matter - into neutral massless particles. Using the Einstein relation on the equivalence of energy and mass (E=mc 2), it is easy to calculate that the annihilation of one gram of matter produces the same energy that can be obtained by burning 10,000 tons of coal, and one ton of antimatter would be enough to provide the entire planet with energy for a year.

Astrophysicists believe that it is annihilation that provides the gigantic energy of quasi-stellar objects - quasars.

In 1979, a group of American physicists managed to register the presence of natural antiprotons. They were brought by cosmic rays.

Nuclear energy is a terrible and at the same time a wonderful force. Radioactive decay and nuclear reactions that take place in atoms release an enormous amount of energy that people try to use. They are trying, because the development of nuclear energy not only involved many victims, but also catastrophes (for example, the Chernobyl nuclear power plant). Nevertheless, nuclear power plants around the world are operating and produce about 15 percent of the world's electricity. Nuclear reactors are available in 31 countries of the world. Ships and submarines are also equipped with nuclear reactors. In any case, the attitude towards nuclear energy and in general everything related to nuclear decay (as opposed to fusion) is deteriorating every year. The day will come when the energy of the atom will be exclusively peaceful.

In the last episodes of the Chernobyl series by the HBO television company, Russian scientists reveal the truth about the cause of the explosion of the reactor of the 4th power unit of the Chernobyl nuclear power plant, which subsequently “pollinated” the territories of 17 European countries with a total area of ​​207.5 thousand square kilometers with radioactive cesium. The disaster at the Chernobyl nuclear power plant revealed fundamental flaws in the RBMK-1000 reactor. Despite this, today 10 RBMK-1000 reactors are still operating in Russia. Are they safe? According to Western experts in nuclear physics, who shared their opinion with the Live Science portal, this question remains open.

Atom It consists of a nucleus around which particles called electrons revolve.

The nuclei of atoms are the smallest particles. They are the basis for all substance and matter.

They contain a large amount of energy.

This energy is released as radiation when certain radioactive elements decay. Radiation is dangerous for all life on earth, but at the same time it is used to produce electricity and in medicine.

Radioactivity is the property of the nuclei of unstable atoms to radiate energy. Most heavy atoms are unstable, and lighter atoms have radioisotopes, i.e. radioactive isotopes. The reason for the appearance of radioactivity is that the atoms strive to obtain stability. Today, three types of radioactive radiation are known: alpha, beta and gamma. They were named after the first letters of the Greek alphabet. The nucleus first emits alpha or beta rays. But if it still remains unstable, then gamma rays come out. Three atomic nuclei can be unstable, and each of them can emit any of the types of rays.

The figure shows three atomic nuclei.

They are unstable and each of them emits one of three types of beams.

Alpha particles have two protons and two neutrons. The core of the helium atom has exactly the same composition. Alpha particles move slowly and therefore any material thicker than a paper sheet can hold them. They are not much different from the nuclei of helium atoms. Most scientists put forward the version that helium on Earth is of natural radioactive origin.

Beta particles are electrons with enormous energy. Their formation occurs during the decay of neutrons. Beta particles are also not very fast, they can fly through the air up to one meter. Therefore, a millimeter-thick copper sheet can become an obstacle in their path. And if you set up a 13 mm lead barrier or 120 meters of air, you can halve gamma radiation.

Gamma rays are electromagnetic radiation of great energy. Its speed of movement is equal to the speed of light.

Transportation of radioactive substances is carried out in special lead containers with thick walls to prevent leakage of radiation.

Exposure to radiation is extremely dangerous for humans.

It causes burns, cataracts, provokes the development of cancer.

A special device, the Geiger counter, helps to measure the level of radiation, which makes clicking sounds when a source of radiation appears.

When a nucleus emits particles, it turns into the nucleus of another element, thus changing its atomic number. This is called the decay period of the element. But if the newly formed element is still unstable, then the decay process continues. And so on until the element becomes stable. For many radioactive elements, this period takes tens, hundreds and even thousands of years, so it is customary to measure the half-life. Take, for example, a plutonium-2 atom with a mass of 242. After emitting alpha particles with a relative atomic mass of 4, it becomes a uranium-238 atom with the same atomic mass.

Nuclear reactions.

Nuclear reactions are divided into two types: nuclear fusion and fission (splitting) of the nucleus.

Synthesis or otherwise "connection" means the connection of two nuclei into one large one under the influence of very high temperature. At this point, a large amount of energy is released.

During fission and fission, the process of fission of the nucleus occurs, while releasing nuclear energy.

This happens when the nucleus is bombarded with neutrons in a special device called a "particle accelerator".

During the fission of the nucleus and the radiation of neutrons, just a colossal amount of energy is released.

It is known that to obtain a large amount of electricity, only a unit mass of radio fuel is needed.No other power plant can boast of anything like it.

Nuclear power.

Thus, the energy that is released during a nuclear reaction is used to generate electricity or as an energy source in underwater and surface ships. The process of generating electricity at a nuclear power plant is based on nuclear fission in nuclear reactors. In a huge tank are rods of a radioactive substance (for example, uranium).

They are attacked by neutrons and split, releasing energy. New neutrons are split further and further. This is called a chain reaction. The efficiency of this method of generating electricity is incredibly high, but the security measures and burial conditions are too expensive.

However, mankind uses nuclear energy not only for peaceful purposes. In the middle of the 20th century, nuclear weapons were tested and tested.

Its action is to release a huge flow of energy, which leads to an explosion. At the end of World War II, the United States used nuclear weapons against Japan. They dropped atomic bombs on the cities of Hiroshima and Nagasaki.

The consequences were simply disastrous.

Some human victims were several hundred thousand.

But scientists did not stop there and developed hydrogen weapons.

Their difference is that nuclear bombs are based on nuclear fission reactions, and hydrogen bombs on fusion reactions.

radiocarbon method.

To obtain information about the time of death of an organism, the method of radiocarbon analysis is used. It is known that living tissue contains some amount of carbon-14, which is a radioactive isotope of carbon. The half-life of which is 5700 years. After the death of the organism, the reserves of carbon-14 in the tissues decrease, the isotope decays, and the time of death of the organism is determined from its remaining amount. So, for example, you can find out how long ago a volcano erupted. This can be recognized by insects and pollen frozen in lava.

How else is radioactivity used?

Radiation is also used in industry.

Gamma rays are used to irradiate food to keep it fresh.

In medicine, radiation is used in the study of internal organs.

There is also a technique called radiotherapy. This is when the patient is irradiated with small doses, destroying cancer cells in his body.