Atomic bombs. The history of the creation and principle of operation of the atomic bomb How the atomic bomb works - diagram

An atomic bomb is a projectile designed to produce a high-power explosion as a result of a very rapid release of nuclear (atomic) energy.

The principle of operation of atomic bombs

The nuclear charge is divided into several parts to critical sizes so that in each of them a self-developing uncontrolled chain reaction of fission of atoms of the fissile substance cannot begin. Such a reaction will occur only when all parts of the charge are quickly connected into one whole. The completeness of the reaction and, ultimately, the power of the explosion greatly depends on the speed of convergence of the individual parts. To impart high speed to parts of the charge, an explosion of a conventional explosive can be used. If parts of a nuclear charge are placed in radial directions at a certain distance from the center, and TNT charges are placed on the outside, then it is possible to carry out an explosion of conventional charges directed towards the center of the nuclear charge. All parts of the nuclear charge will not only combine into a single whole with enormous speed, but will also find themselves for some time compressed on all sides by the enormous pressure of the explosion products and will not be able to separate immediately as soon as a nuclear chain reaction begins in the charge. As a result of this, significantly greater fission will occur than without such compression, and, consequently, the power of the explosion will increase. A neutron reflector also contributes to an increase in the explosion power for the same amount of fissile material (the most effective reflectors are beryllium< Be >, graphite, heavy water< H3O >). The first fission, which would start a chain reaction, requires at least one neutron. It is impossible to count on the timely start of a chain reaction under the influence of neutrons appearing during the spontaneous fission of nuclei, because it occurs relatively rarely: for U-235 - 1 decay per hour per 1 g. substances. There are also very few neutrons existing in free form in the atmosphere: through S = 1 cm/sq. On average, about 6 neutrons fly by per second. For this reason, an artificial source of neutrons is used in a nuclear charge - a kind of nuclear detonator capsule. It also ensures that many fissions begin simultaneously, so the reaction proceeds in the form of a nuclear explosion.

Detonation options (Gun and implosion schemes)

There are two main schemes for detonating a fissile charge: cannon, otherwise called ballistic, and implosive.

The "cannon design" was used in some first generation nuclear weapons. The essence of the cannon circuit is to shoot a charge of gunpowder from one block of fissile material of subcritical mass (“bullet”) into another stationary one (“target”). The blocks are designed so that when connected, their total mass becomes supercritical.

This detonation method is possible only in uranium ammunition, since plutonium has a two orders of magnitude higher neutron background, which sharply increases the likelihood of premature development of a chain reaction before the blocks are connected. This leads to an incomplete release of energy (the so-called “fizzy”, English). To implement the cannon circuit in plutonium ammunition, it is necessary to increase the speed of connection of the charge parts to a technically unattainable level. In addition, uranium withstands mechanical overloads better than plutonium.

Implosive scheme. This detonation scheme involves achieving a supercritical state by compressing the fissile material with a focused shock wave created by the explosion of a chemical explosive. To focus the shock wave, so-called explosive lenses are used, and the detonation is carried out simultaneously at many points with precision accuracy. The creation of such a system for the placement of explosives and detonation was at one time one of the most difficult tasks. The formation of a converging shock wave was ensured by the use of explosive lenses from “fast” and “slow” explosives - TATV (Triaminotrinitrobenzene) and baratol (a mixture of trinitrotoluene with barium nitrate), and some additives)

The world of the atom is so fantastic that understanding it requires a radical break in the usual concepts of space and time. Atoms are so small that if a drop of water could be enlarged to the size of the Earth, each atom in that drop would be smaller than an orange. In fact, one drop of water consists of 6000 billion billion (6000000000000000000000) hydrogen and oxygen atoms. And yet, despite its microscopic size, the atom has a structure to some extent similar to the structure of our solar system. In its incomprehensibly small center, the radius of which is less than one trillionth of a centimeter, there is a relatively huge “sun” - the nucleus of an atom.

Tiny “planets” - electrons - revolve around this atomic “sun”. The nucleus consists of the two main building blocks of the Universe - protons and neutrons (they have a unifying name - nucleons). An electron and a proton are charged particles, and the amount of charge in each of them is exactly the same, but the charges differ in sign: the proton is always positively charged, and the electron is negatively charged. The neutron does not carry an electrical charge and, as a result, has a very high permeability.

In the atomic scale of measurements, the mass of a proton and neutron is taken as unity. The atomic weight of any chemical element therefore depends on the number of protons and neutrons contained in its nucleus. For example, a hydrogen atom, with a nucleus consisting of only one proton, has an atomic mass of 1. A helium atom, with a nucleus of two protons and two neutrons, has an atomic mass of 4.

The nuclei of atoms of the same element always contain the same number of protons, but the number of neutrons may vary. Atoms that have nuclei with the same number of protons, but differ in the number of neutrons and are varieties of the same element are called isotopes. To distinguish them from each other, a number is assigned to the symbol of the element equal to the sum of all particles in the nucleus of a given isotope.

The question may arise: why does the nucleus of an atom not fall apart? After all, the protons included in it are electrically charged particles with the same charge, which must repel each other with great force. This is explained by the fact that inside the nucleus there are also so-called intranuclear forces that attract nuclear particles to each other. These forces compensate for the repulsive forces of protons and prevent the nucleus from spontaneously flying apart.

Intranuclear forces are very strong, but act only at very close distances. Therefore, the nuclei of heavy elements, consisting of hundreds of nucleons, turn out to be unstable. The particles of the nucleus are in continuous motion here (within the volume of the nucleus), and if you add some additional amount of energy to them, they can overcome the internal forces - the nucleus will split into parts. The amount of this excess energy is called excitation energy. Among the isotopes of heavy elements, there are those that seem to be on the very verge of self-disintegration. Just a small “push” is enough, for example, a simple neutron hitting the nucleus (and it does not even have to accelerate to high speed) for the nuclear fission reaction to occur. Some of these “fissile” isotopes were later learned to be produced artificially. In nature, there is only one such isotope - uranium-235.

Uranus was discovered in 1783 by Klaproth, who isolated it from uranium tar and named it after the recently discovered planet Uranus. As it turned out later, it was, in fact, not uranium itself, but its oxide. Pure uranium, a silvery-white metal, was obtained
only in 1842 Peligo. The new element did not have any remarkable properties and did not attract attention until 1896, when Becquerel discovered the phenomenon of radioactivity in uranium salts. After this, uranium became the object of scientific research and experimentation, but still had no practical use.

When, in the first third of the 20th century, physicists more or less understood the structure of the atomic nucleus, they first of all tried to fulfill the long-standing dream of alchemists - they tried to transform one chemical element into another. In 1934, French researchers, the spouses Frederic and Irene Joliot-Curie, reported to the French Academy of Sciences about the following experience: when bombarding aluminum plates with alpha particles (nuclei of a helium atom), aluminum atoms turned into phosphorus atoms, but not ordinary ones, but radioactive ones, which in turn became into a stable isotope of silicon. Thus, an aluminum atom, having added one proton and two neutrons, turned into a heavier silicon atom.

This experience suggested that if you “bombard” the nuclei of the heaviest element existing in nature - uranium - with neutrons, you can obtain an element that does not exist in natural conditions. In 1938, German chemists Otto Hahn and Fritz Strassmann repeated in general terms the experience of the Joliot-Curie spouses, using uranium instead of aluminum. The results of the experiment were not at all what they expected - instead of a new superheavy element with a mass number greater than that of uranium, Hahn and Strassmann received light elements from the middle part of the periodic table: barium, krypton, bromine and some others. The experimenters themselves were unable to explain the observed phenomenon. Only the following year, physicist Lise Meitner, to whom Hahn reported his difficulties, found the correct explanation for the observed phenomenon, suggesting that when uranium is bombarded with neutrons, its nucleus splits (fissions). In this case, nuclei of lighter elements should have been formed (that’s where barium, krypton and other substances came from), as well as 2-3 free neutrons should have been released. Further research made it possible to clarify in detail the picture of what was happening.

Natural uranium consists of a mixture of three isotopes with masses 238, 234 and 235. The main amount of uranium is isotope-238, the nucleus of which includes 92 protons and 146 neutrons. Uranium-235 is only 1/140 of natural uranium (0.7% (it has 92 protons and 143 neutrons in its nucleus), and uranium-234 (92 protons, 142 neutrons) is only 1/17500 of the total mass of uranium (0 , 006%.The least stable of these isotopes is uranium-235.

From time to time, the nuclei of its atoms spontaneously divide into parts, as a result of which lighter elements of the periodic table are formed. The process is accompanied by the release of two or three free neutrons, which rush at enormous speed - about 10 thousand km/s (they are called fast neutrons). These neutrons can hit other uranium nuclei, causing nuclear reactions. Each isotope behaves differently in this case. Uranium-238 nuclei in most cases simply capture these neutrons without any further transformations. But in approximately one case out of five, when a fast neutron collides with the nucleus of the isotope-238, a curious nuclear reaction occurs: one of the neutrons of uranium-238 emits an electron, turning into a proton, that is, the uranium isotope turns into a more
heavy element - neptunium-239 (93 protons + 146 neutrons). But neptunium is unstable - after a few minutes, one of its neutrons emits an electron, turning into a proton, after which the neptunium isotope turns into the next element in the periodic table - plutonium-239 (94 protons + 145 neutrons). If a neutron hits the nucleus of unstable uranium-235, then fission immediately occurs - the atoms disintegrate with the emission of two or three neutrons. It is clear that in natural uranium, most of the atoms of which belong to the isotope-238, this reaction has no visible consequences - all free neutrons will eventually be absorbed by this isotope.

Well, what if we imagine a fairly massive piece of uranium consisting entirely of isotope-235?

Here the process will go differently: neutrons released during the fission of several nuclei, in turn, hitting neighboring nuclei, cause their fission. As a result, a new portion of neutrons is released, which splits the next nuclei. Under favorable conditions, this reaction proceeds like an avalanche and is called a chain reaction. To start it, a few bombarding particles may be enough.

Indeed, let uranium-235 be bombarded by only 100 neutrons. They will separate 100 uranium nuclei. In this case, 250 new neutrons of the second generation will be released (on average 2.5 per fission). Second generation neutrons will produce 250 fissions, which will release 625 neutrons. In the next generation it will become 1562, then 3906, then 9670, etc. The number of divisions will increase indefinitely if the process is not stopped.

However, in reality only a small fraction of neutrons reach the nuclei of atoms. The rest, quickly rushing between them, are carried away into the surrounding space. A self-sustaining chain reaction can only occur in a sufficiently large array of uranium-235, which is said to have a critical mass. (This mass under normal conditions is 50 kg.) It is important to note that the fission of each nucleus is accompanied by the release of a huge amount of energy, which turns out to be approximately 300 million times more than the energy spent on fission! (It is estimated that the complete fission of 1 kg of uranium-235 releases the same amount of heat as the combustion of 3 thousand tons of coal.)

This colossal burst of energy, released in a matter of moments, manifests itself as an explosion of monstrous force and underlies the action of nuclear weapons. But in order for this weapon to become a reality, it is necessary that the charge consist not of natural uranium, but of a rare isotope - 235 (such uranium is called enriched). It was later discovered that pure plutonium is also a fissile material and could be used in an atomic charge instead of uranium-235.

All these important discoveries were made on the eve of World War II. Soon, secret work on creating an atomic bomb began in Germany and other countries. In the USA, this problem was addressed in 1941. The entire complex of works was given the name “Manhattan Project”.

Administrative management of the project was carried out by General Groves, and scientific management was carried out by University of California professor Robert Oppenheimer. Both were well aware of the enormous complexity of the task facing them. Therefore, Oppenheimer's first concern was recruiting a highly intelligent scientific team. In the USA at that time there were many physicists who emigrated from Nazi Germany. It was not easy to attract them to create weapons directed against their former homeland. Oppenheimer spoke personally to everyone, using all the power of his charm. Soon he managed to gather a small group of theorists, whom he jokingly called “luminaries.” And in fact, it included the greatest specialists of that time in the field of physics and chemistry. (Among them are 13 Nobel Prize laureates, including Bohr, Fermi, Frank, Chadwick, Lawrence.) Besides them, there were many other specialists of various profiles.

The US government did not skimp on expenses, and the work took on a grand scale from the very beginning. In 1942, the world's largest research laboratory was founded at Los Alamos. The population of this scientific city soon reached 9 thousand people. In terms of the composition of scientists, the scope of scientific experiments, and the number of specialists and workers involved in the work, the Los Alamos Laboratory had no equal in world history. The Manhattan Project had its own police, counterintelligence, communications system, warehouses, villages, factories, laboratories, and its own colossal budget.

The main goal of the project was to obtain enough fissile material from which several atomic bombs could be created. In addition to uranium-235, the charge for the bomb, as already mentioned, could be the artificial element plutonium-239, that is, the bomb could be either uranium or plutonium.

Groves And Oppenheimer agreed that work should be carried out simultaneously in two directions, since it is impossible to decide in advance which of them will be more promising. Both methods were fundamentally different from each other: the accumulation of uranium-235 had to be carried out by separating it from the bulk of natural uranium, and plutonium could only be obtained as a result of a controlled nuclear reaction when uranium-238 was irradiated with neutrons. Both paths seemed unusually difficult and did not promise easy solutions.

In fact, how can one separate two isotopes that differ only slightly in weight and chemically behave in exactly the same way? Neither science nor technology has ever faced such a problem. The production of plutonium also seemed very problematic at first. Before this, the entire experience of nuclear transformations was reduced to a few laboratory experiments. Now they had to master the production of kilograms of plutonium on an industrial scale, develop and create a special installation for this - a nuclear reactor, and learn to control the course of the nuclear reaction.

Both there and here a whole complex of complex problems had to be solved. Therefore, the Manhattan Project consisted of several subprojects, headed by prominent scientists. Oppenheimer himself was the head of the Los Alamos Scientific Laboratory. Lawrence was in charge of the Radiation Laboratory at the University of California. Fermi conducted research at the University of Chicago to create a nuclear reactor.

At first, the most important problem was obtaining uranium. Before the war, this metal had virtually no use. Now that it was needed immediately in huge quantities, it turned out that there was no industrial method of producing it.

The Westinghouse company took up its development and quickly achieved success. After purifying the uranium resin (uranium occurs in nature in this form) and obtaining uranium oxide, it was converted into tetrafluoride (UF4), from which uranium metal was separated by electrolysis. If at the end of 1941 American scientists had only a few grams of uranium metal at their disposal, then already in November 1942 its industrial production at Westinghouse factories reached 6,000 pounds per month.

At the same time, work was underway to create a nuclear reactor. The process of producing plutonium actually boiled down to irradiating uranium rods with neutrons, as a result of which part of the uranium-238 would turn into plutonium. The sources of neutrons in this case could be fissile atoms of uranium-235, scattered in sufficient quantities among atoms of uranium-238. But in order to maintain the constant production of neutrons, a chain reaction of fission of uranium-235 atoms had to begin. Meanwhile, as already mentioned, for every atom of uranium-235 there were 140 atoms of uranium-238. It is clear that neutrons scattering in all directions had a much higher probability of meeting them on their way. That is, a huge number of released neutrons turned out to be absorbed by the main isotope without any benefit. Obviously, under such conditions a chain reaction could not take place. How to be?

At first it seemed that without the separation of two isotopes, the operation of the reactor was generally impossible, but one important circumstance was soon established: it turned out that uranium-235 and uranium-238 were susceptible to neutrons of different energies. The nucleus of a uranium-235 atom can be split by a neutron of relatively low energy, having a speed of about 22 m/s. Such slow neutrons are not captured by uranium-238 nuclei - for this they must have a speed of the order of hundreds of thousands of meters per second. In other words, uranium-238 is powerless to prevent the beginning and progress of a chain reaction in uranium-235 caused by neutrons slowed down to extremely low speeds - no more than 22 m/s. This phenomenon was discovered by the Italian physicist Fermi, who lived in the USA since 1938 and led the work here to create the first reactor. Fermi decided to use graphite as a neutron moderator. According to his calculations, the neutrons emitted from uranium-235, having passed through a 40 cm layer of graphite, should have reduced their speed to 22 m/s and begun a self-sustaining chain reaction in uranium-235.

Another moderator could be so-called “heavy” water. Since the hydrogen atoms included in it are very similar in size and mass to neutrons, they could best slow them down. (With fast neutrons, approximately the same thing happens as with balls: if a small ball hits a large one, it rolls back, almost without losing speed, but when it meets a small ball, it transfers a significant part of its energy to it - just like a neutron in an elastic collision bounces off a heavy nucleus, slowing down only slightly, and when colliding with the nuclei of hydrogen atoms, it very quickly loses all its energy.) However, ordinary water is not suitable for slowing down, since its hydrogen tends to absorb neutrons. That is why deuterium, which is part of “heavy” water, should be used for this purpose.

In early 1942, under Fermi's leadership, construction began on the first nuclear reactor in history in the tennis court area under the west stands of Chicago Stadium. The scientists carried out all the work themselves. The reaction can be controlled in the only way - by adjusting the number of neutrons participating in the chain reaction. Fermi intended to achieve this using rods made of substances such as boron and cadmium, which strongly absorb neutrons. The moderator was graphite bricks, from which the physicists built columns 3 m high and 1.2 m wide. Rectangular blocks with uranium oxide were installed between them. The entire structure required about 46 tons of uranium oxide and 385 tons of graphite. To slow down the reaction, rods of cadmium and boron were introduced into the reactor.

If this were not enough, then for insurance, two scientists stood on a platform located above the reactor with buckets filled with a solution of cadmium salts - they were supposed to pour them onto the reactor if the reaction got out of control. Fortunately, this was not necessary. On December 2, 1942, Fermi ordered all control rods to be extended and the experiment began. After four minutes, the neutron counters began to click louder and louder. With every minute the intensity of the neutron flux became greater. This indicated that a chain reaction was taking place in the reactor. It lasted for 28 minutes. Then Fermi gave the signal, and the lowered rods stopped the process. Thus, for the first time, man freed the energy of the atomic nucleus and proved that he could control it at will. Now there was no longer any doubt that nuclear weapons were a reality.

In 1943, the Fermi reactor was dismantled and transported to the Aragonese National Laboratory (50 km from Chicago). Another nuclear reactor was soon built here, using heavy water as a moderator. It consisted of a cylindrical aluminum tank containing 6.5 tons of heavy water, into which were vertically immersed 120 rods of uranium metal, encased in an aluminum shell. The seven control rods were made of cadmium. Around the tank there was a graphite reflector, then a screen made of lead and cadmium alloys. The entire structure was enclosed in a concrete shell with a wall thickness of about 2.5 m.

Experiments at these pilot reactors confirmed the possibility of industrial production of plutonium.

The main center of the Manhattan Project soon became the town of Oak Ridge in the Tennessee River Valley, whose population grew to 79 thousand people in a few months. Here, the first enriched uranium production plant in history was built in a short time. An industrial reactor producing plutonium was launched here in 1943. In February 1944, about 300 kg of uranium was extracted from it daily, from the surface of which plutonium was obtained by chemical separation. (To do this, the plutonium was first dissolved and then precipitated.) The purified uranium was then returned to the reactor. That same year, construction began on the huge Hanford plant in the barren, bleak desert on the south bank of the Columbia River. Three powerful nuclear reactors were located here, producing several hundred grams of plutonium every day.

In parallel, research was in full swing to develop an industrial process for uranium enrichment.

After considering various options, Groves and Oppenheimer decided to focus their efforts on two methods: gaseous diffusion and electromagnetic.

The gas diffusion method was based on a principle known as Graham's law (it was first formulated in 1829 by the Scottish chemist Thomas Graham and developed in 1896 by the English physicist Reilly). According to this law, if two gases, one of which is lighter than the other, are passed through a filter with negligibly small holes, then slightly more of the light gas will pass through it than of the heavy one. In November 1942, Urey and Dunning from Columbia University created a gaseous diffusion method for separating uranium isotopes based on the Reilly method.

Since natural uranium is a solid, it was first converted into uranium fluoride (UF6). This gas was then passed through microscopic - on the order of thousandths of a millimeter - holes in the filter partition.

Since the difference in the molar weights of the gases was very small, behind the partition the content of uranium-235 increased by only 1.0002 times.

In order to increase the amount of uranium-235 even more, the resulting mixture is again passed through a partition, and the amount of uranium is again increased by 1.0002 times. Thus, to increase the uranium-235 content to 99%, it was necessary to pass the gas through 4000 filters. This took place at a huge gaseous diffusion plant in Oak Ridge.

In 1940, under the leadership of Ernest Lawrence, research began on the separation of uranium isotopes by the electromagnetic method at the University of California. It was necessary to find physical processes that would allow isotopes to be separated using the difference in their masses. Lawrence attempted to separate isotopes using the principle of a mass spectrograph, an instrument used to determine the masses of atoms.

The principle of its operation was as follows: pre-ionized atoms were accelerated by an electric field and then passed through a magnetic field, in which they described circles located in a plane perpendicular to the direction of the field. Since the radii of these trajectories were proportional to the mass, light ions ended up on circles of smaller radius than heavy ones. If traps were placed along the path of the atoms, then different isotopes could be collected separately in this way.

That was the method. In laboratory conditions it gave good results. But building a facility where isotope separation could be carried out on an industrial scale proved extremely difficult. However, Lawrence eventually managed to overcome all difficulties. The result of his efforts was the appearance of calutron, which was installed in a giant plant in Oak Ridge.

This electromagnetic plant was built in 1943 and turned out to be perhaps the most expensive brainchild of the Manhattan Project. Lawrence's method required a large number of complex, not yet developed devices involving high voltage, high vacuum and strong magnetic fields. The scale of the costs turned out to be enormous. Calutron had a giant electromagnet, the length of which reached 75 m and weighed about 4000 tons.

Several thousand tons of silver wire were used for the windings for this electromagnet.

The entire work (not counting the cost of $300 million in silver, which the State Treasury provided only temporarily) cost $400 million. The Ministry of Defense paid 10 million for the electricity consumed by calutron alone. Much of the equipment at the Oak Ridge plant was superior in scale and precision to anything that had ever been developed in this field of technology.

But all these costs were not in vain. Having spent a total of about 2 billion dollars, US scientists by 1944 created a unique technology for uranium enrichment and plutonium production. Meanwhile, at the Los Alamos laboratory they were working on the design of the bomb itself. The principle of its operation was in general terms clear for a long time: the fissile substance (plutonium or uranium-235) had to be transferred to a critical state at the moment of explosion (for a chain reaction to occur, the charge mass should be even noticeably greater than the critical one) and irradiated with a neutron beam, which entailed is the beginning of a chain reaction.

According to calculations, the critical mass of the charge exceeded 50 kilograms, but they were able to significantly reduce it. In general, the value of the critical mass is strongly influenced by several factors. The larger the surface area of ​​the charge, the more neutrons are uselessly emitted into the surrounding space. A sphere has the smallest surface area. Consequently, spherical charges, other things being equal, have the smallest critical mass. In addition, the value of the critical mass depends on the purity and type of fissile materials. It is inversely proportional to the square of the density of this material, which allows, for example, by doubling the density, reducing the critical mass by four times. The required degree of subcriticality can be obtained, for example, by compacting the fissile material due to the explosion of a charge of a conventional explosive made in the form of a spherical shell surrounding the nuclear charge. The critical mass can also be reduced by surrounding the charge with a screen that reflects neutrons well. Lead, beryllium, tungsten, natural uranium, iron and many others can be used as such a screen.

One possible design of an atomic bomb consists of two pieces of uranium, which, when combined, form a mass greater than critical. In order to cause a bomb explosion, you need to bring them closer together as quickly as possible. The second method is based on the use of an inward-converging explosion. In this case, a stream of gases from a conventional explosive was directed at the fissile material located inside and compressed it until it reached a critical mass. Combining a charge and intensely irradiating it with neutrons, as already mentioned, causes a chain reaction, as a result of which in the first second the temperature increases to 1 million degrees. During this time, only about 5% of the critical mass managed to separate. The rest of the charge in early bomb designs evaporated without
any benefit.

The first atomic bomb in history (it was given the name Trinity) was assembled in the summer of 1945. And on June 16, 1945, the first atomic explosion on Earth was carried out at the nuclear test site in the Alamogordo desert (New Mexico). The bomb was placed in the center of the test site on top of a 30-meter steel tower. Recording equipment was placed around it at a great distance. There was an observation post 9 km away, and a command post 16 km away. The atomic explosion made a stunning impression on all witnesses to this event. According to eyewitnesses' descriptions, it felt as if many suns had united into one and illuminated the test site at once. Then a huge fireball appeared over the plain and a round cloud of dust and light began to rise towards it slowly and ominously.

Taking off from the ground, this fireball soared to a height of more than three kilometers in a few seconds. With every moment it grew in size, soon its diameter reached 1.5 km, and it slowly rose into the stratosphere. Then the fireball gave way to a column of billowing smoke, which stretched to a height of 12 km, taking the shape of a giant mushroom. All this was accompanied by a terrible roar, from which the earth shook. The power of the exploding bomb exceeded all expectations.

As soon as the radiation situation allowed, several Sherman tanks, lined with lead plates on the inside, rushed to the area of ​​the explosion. On one of them was Fermi, who was eager to see the results of his work. What appeared before his eyes was a dead, scorched earth, on which all living things had been destroyed within a radius of 1.5 km. The sand had baked into a glassy greenish crust that covered the ground. In a huge crater lay the mangled remains of a steel support tower. The force of the explosion was estimated at 20,000 tons of TNT.

The next step was to be the combat use of the atomic bomb against Japan, which, after the surrender of Nazi Germany, alone continued the war with the United States and its allies. There were no launch vehicles at that time, so the bombing had to be carried out from an airplane. The components of the two bombs were transported with great care by the cruiser Indianapolis to Tinian Island, where the 509th Combined Air Force Group was based. These bombs differed somewhat from each other in the type of charge and design.

The first atomic bomb - "Baby" - was a large-sized aerial bomb with an atomic charge made of highly enriched uranium-235. Its length was about 3 m, diameter - 62 cm, weight - 4.1 tons.

The second atomic bomb - "Fat Man" - with a charge of plutonium-239 was egg-shaped with a large stabilizer. Its length
was 3.2 m, diameter 1.5 m, weight - 4.5 tons.

On August 6, Colonel Tibbets' B-29 Enola Gay bomber dropped "Little Boy" on the major Japanese city of Hiroshima. The bomb was lowered by parachute and exploded, as planned, at an altitude of 600 m from the ground.

The consequences of the explosion were terrible. Even for the pilots themselves, the sight of a peaceful city destroyed by them in an instant made a depressing impression. Later, one of them admitted that at that second they saw the worst thing a person can see.

For those who were on earth, what was happening resembled true hell. First of all, a heat wave passed over Hiroshima. Its effect lasted only a few moments, but was so powerful that it melted even tiles and quartz crystals in granite slabs, turned telephone poles at a distance of 4 km into coal and, finally, incinerated human bodies so much that only shadows remained from them on the asphalt of the pavements or on the walls of houses. Then a monstrous gust of wind burst out from under the fireball and rushed over the city at a speed of 800 km/h, destroying everything in its path. Houses that could not withstand his furious onslaught collapsed as if knocked down. There is not a single intact building left in the giant circle with a diameter of 4 km. A few minutes after the explosion, black radioactive rain fell over the city - this moisture turned into steam condensed in the high layers of the atmosphere and fell to the ground in the form of large drops mixed with radioactive dust.

After the rain, a new gust of wind hit the city, this time blowing in the direction of the epicenter. It was weaker than the first, but still strong enough to uproot trees. The wind fanned a gigantic fire in which everything that could burn burned. Of the 76 thousand buildings, 55 thousand were completely destroyed and burned. Witnesses of this terrible catastrophe recalled torch-men, from whom burnt clothes fell to the ground along with rags of skin, and of crowds of maddened people, covered with terrible burns, rushing screaming through the streets. There was a suffocating stench of burnt human flesh in the air. There were people lying everywhere, dead and dying. There were many who were blind and deaf and, poking in all directions, could not make out anything in the chaos that reigned around them.

The unfortunate people, who were located at a distance of up to 800 m from the epicenter, literally burned out in a split second - their insides evaporated and their bodies turned into lumps of smoking coals. Those located 1 km from the epicenter were affected by radiation sickness in an extremely severe form. Within a few hours, they began to vomit violently, their temperature jumped to 39-40 degrees, and they began to experience shortness of breath and bleeding. Then non-healing ulcers appeared on the skin, the composition of the blood changed dramatically, and hair fell out. After terrible suffering, usually on the second or third day, death occurred.

In total, about 240 thousand people died from the explosion and radiation sickness. About 160 thousand received radiation sickness in a milder form - their painful death was delayed by several months or years. When news of the disaster spread throughout the country, all of Japan was paralyzed with fear. It increased further after Major Sweeney's Box Car dropped a second bomb on Nagasaki on August 9. Several hundred thousand inhabitants were also killed and injured here. Unable to resist the new weapons, the Japanese government capitulated - the atomic bomb ended World War II.

War is over. It lasted only six years, but managed to change the world and people almost beyond recognition.

Human civilization before 1939 and human civilization after 1945 are strikingly different from each other. There are many reasons for this, but one of the most important is the emergence of nuclear weapons. It can be said without exaggeration that the shadow of Hiroshima lies over the entire second half of the 20th century. It became a deep moral burn for many millions of people, both contemporaries of this catastrophe and those born decades after it. Modern man can no longer think about the world the way they thought about it before August 6, 1945 - he understands too clearly that this world can turn into nothing in a few moments.

Modern man cannot look at war the way his grandfathers and great-grandfathers did - he knows for certain that this war will be the last, and there will be neither winners nor losers in it. Nuclear weapons have left their mark on all spheres of public life, and modern civilization cannot live by the same laws as sixty or eighty years ago. No one understood this better than the creators of the atomic bomb themselves.

"People of our planet , wrote Robert Oppenheimer, must unite. The horror and destruction sown by the last war dictate this thought to us. The explosions of atomic bombs proved it with all cruelty. Other people at other times have already said similar words - only about other weapons and about other wars. They weren't successful. But anyone who today would say that these words are useless is misled by the vicissitudes of history. We cannot be convinced of this. The results of our work leave humanity no choice but to create a united world. A world based on legality and humanity."

North Korea threatens the US with testing a super-powerful hydrogen bomb in the Pacific Ocean. Japan, which may suffer as a result of the tests, called North Korea's plans completely unacceptable. Presidents Donald Trump and Kim Jong-un argue in interviews and talk about open military conflict. For those who do not understand nuclear weapons, but want to be in the know, The Futurist has compiled a guide.

How do nuclear weapons work?

Like a regular stick of dynamite, a nuclear bomb uses energy. Only it is released not during a primitive chemical reaction, but in complex nuclear processes. There are two main ways to extract nuclear energy from an atom. IN nuclear fission the nucleus of an atom decays into two smaller fragments with a neutron. Nuclear fusion – the process by which the Sun produces energy – involves the joining of two smaller atoms to form a larger one. In any process, fission or fusion, large amounts of thermal energy and radiation are released. Depending on whether nuclear fission or fusion is used, bombs are divided into nuclear (atomic) And thermonuclear .

Can you tell me more about nuclear fission?

Atomic bomb explosion over Hiroshima (1945)

As you remember, an atom is made up of three types of subatomic particles: protons, neutrons and electrons. The center of the atom, called core , consists of protons and neutrons. Protons are positively charged, electrons are negatively charged, and neutrons have no charge at all. The proton-electron ratio is always one to one, so the atom as a whole has a neutral charge. For example, a carbon atom has six protons and six electrons. Particles are held together by a fundamental force - strong nuclear force .

The properties of an atom can change significantly depending on how many different particles it contains. If you change the number of protons, you will have a different chemical element. If you change the number of neutrons, you get isotope the same element that you have in your hands. For example, carbon has three isotopes: 1) carbon-12 (six protons + six neutrons), which is a stable and common form of the element, 2) carbon-13 (six protons + seven neutrons), which is stable but rare, and 3) carbon -14 (six protons + eight neutrons), which is rare and unstable (or radioactive).

Most atomic nuclei are stable, but some are unstable (radioactive). These nuclei spontaneously emit particles that scientists call radiation. This process is called radioactive decay . There are three types of decay:

Alpha decay : The nucleus emits an alpha particle - two protons and two neutrons bound together. Beta decay : A neutron turns into a proton, electron and antineutrino. The ejected electron is a beta particle. Spontaneous fission: the nucleus disintegrates into several parts and emits neutrons, and also emits a pulse of electromagnetic energy - a gamma ray. It is the latter type of decay that is used in a nuclear bomb. Free neutrons emitted as a result of fission begin chain reaction , which releases a colossal amount of energy.

What are nuclear bombs made of?

They can be made from uranium-235 and plutonium-239. Uranium occurs in nature as a mixture of three isotopes: 238 U (99.2745% of natural uranium), 235 U (0.72%) and 234 U (0.0055%). The most common 238 U does not support a chain reaction: only 235 U is capable of this. To achieve maximum explosion power, it is necessary that the content of 235 U in the “filling” of the bomb is at least 80%. Therefore, uranium is produced artificially enrich . To do this, the mixture of uranium isotopes is divided into two parts so that one of them contains more than 235 U.

Typically, isotope separation leaves behind a lot of depleted uranium that is unable to undergo a chain reaction—but there is a way to make it do so. The fact is that plutonium-239 does not occur in nature. But it can be obtained by bombarding 238 U with neutrons.

How is their power measured?

​The power of a nuclear and thermonuclear charge is measured in TNT equivalent - the amount of trinitrotoluene that must be detonated to obtain a similar result. It is measured in kilotons (kt) and megatons (Mt). The yield of ultra-small nuclear weapons is less than 1 kt, while super-powerful bombs yield more than 1 mt.

The power of the Soviet “Tsar Bomb” was, according to various sources, from 57 to 58.6 megatons in TNT equivalent; the power of the thermonuclear bomb, which the DPRK tested in early September, was about 100 kilotons.

Who created nuclear weapons?

American physicist Robert Oppenheimer and General Leslie Groves

In the 1930s, Italian physicist Enrico Fermi demonstrated that elements bombarded by neutrons could be transformed into new elements. The result of this work was the discovery slow neutrons , as well as the discovery of new elements not represented on the periodic table. Soon after Fermi's discovery, German scientists Otto Hahn And Fritz Strassmann bombarded uranium with neutrons, resulting in the formation of a radioactive isotope of barium. They concluded that low-speed neutrons cause the uranium nucleus to break into two smaller pieces.

This work excited the minds of the whole world. At Princeton University Niels Bohr worked with John Wheeler to develop a hypothetical model of the fission process. They suggested that uranium-235 undergoes fission. Around the same time, other scientists discovered that the fission process produced even more neutrons. This prompted Bohr and Wheeler to ask an important question: could the free neutrons created by fission start a chain reaction that would release enormous amounts of energy? If this is so, then it is possible to create weapons of unimaginable power. Their assumptions were confirmed by a French physicist Frederic Joliot-Curie . His conclusion became the impetus for developments in the creation of nuclear weapons.

Physicists from Germany, England, the USA, and Japan worked on the creation of atomic weapons. Before the start of World War II Albert Einstein wrote to the US President Franklin Roosevelt that Nazi Germany plans to purify uranium-235 and create an atomic bomb. It now turns out that Germany was far from carrying out a chain reaction: they were working on a “dirty”, highly radioactive bomb. Be that as it may, the US government threw all its efforts into creating an atomic bomb as soon as possible. The Manhattan Project was launched, led by an American physicist Robert Oppenheimer and general Leslie Groves . It was attended by prominent scientists who emigrated from Europe. By the summer of 1945, atomic weapons were created based on two types of fissile material - uranium-235 and plutonium-239. One bomb, the plutonium “Thing,” was detonated during testing, and two more, the uranium “Baby” and the plutonium “Fat Man,” were dropped on the Japanese cities of Hiroshima and Nagasaki.

How does a thermonuclear bomb work and who invented it?

Thermonuclear bomb is based on the reaction nuclear fusion . Unlike nuclear fission, which can occur either spontaneously or forcedly, nuclear fusion is impossible without the supply of external energy. Atomic nuclei are positively charged - so they repel each other. This situation is called the Coulomb barrier. To overcome repulsion, these particles must be accelerated to crazy speeds. This can be done at very high temperatures - on the order of several million Kelvin (hence the name). There are three types of thermonuclear reactions: self-sustaining (take place in the depths of stars), controlled and uncontrolled or explosive - they are used in hydrogen bombs.

The idea of ​​a bomb with thermonuclear fusion initiated by an atomic charge was proposed by Enrico Fermi to his colleague Edward Teller back in 1941, at the very beginning of the Manhattan Project. However, this idea was not in demand at that time. Teller's developments were improved Stanislav Ulam , making the idea of ​​a thermonuclear bomb feasible in practice. In 1952, the first thermonuclear explosive device was tested on Enewetak Atoll during Operation Ivy Mike. However, it was a laboratory sample, unsuitable for combat. A year later, the Soviet Union detonated the world's first thermonuclear bomb, assembled according to the design of physicists Andrey Sakharov And Yulia Kharitona . The device resembled a layer cake, so the formidable weapon was nicknamed “Puff”. In the course of further development, the most powerful bomb on Earth, the “Tsar Bomba” or “Kuzka’s Mother,” was born. In October 1961, it was tested on the Novaya Zemlya archipelago.

What are thermonuclear bombs made of?

If you thought that hydrogen and thermonuclear bombs are different things, you were wrong. These words are synonymous. It is hydrogen (or rather, its isotopes - deuterium and tritium) that is required to carry out a thermonuclear reaction. However, there is a difficulty: in order to detonate a hydrogen bomb, it is first necessary to obtain a high temperature during a conventional nuclear explosion - only then will the atomic nuclei begin to react. Therefore, in the case of a thermonuclear bomb, design plays a big role.

Two schemes are widely known. The first is Sakharov’s “puff pastry”. In the center was a nuclear detonator, which was surrounded by layers of lithium deuteride mixed with tritium, which were interspersed with layers of enriched uranium. This design made it possible to achieve a power within 1 Mt. The second is the American Teller-Ulam scheme, where the nuclear bomb and hydrogen isotopes were located separately. It looked like this: below there was a container with a mixture of liquid deuterium and tritium, in the center of which there was a “spark plug” - a plutonium rod, and on top - a conventional nuclear charge, and all this in a shell of heavy metal (for example, depleted uranium). Fast neutrons produced during the explosion cause atomic fission reactions in the uranium shell and add energy to the total energy of the explosion. Adding additional layers of lithium uranium-238 deuteride makes it possible to create projectiles of unlimited power. In 1953, Soviet physicist Victor Davidenko accidentally repeated the Teller-Ulam idea, and on its basis Sakharov came up with a multi-stage scheme that made it possible to create weapons of unprecedented power. “Kuzka’s Mother” worked exactly according to this scheme.

What other bombs are there?

There are also neutron ones, but this is generally scary. Essentially, a neutron bomb is a low-power thermonuclear bomb, 80% of the explosion energy of which is radiation (neutron radiation). It looks like an ordinary low-power nuclear charge, to which a block with a beryllium isotope - a source of neutrons - has been added. When a nuclear charge explodes, a thermonuclear reaction is triggered. This type of weapon was developed by an American physicist Samuel Cohen . It was believed that neutron weapons destroy all living things, even in shelters, but the range of destruction of such weapons is small, since the atmosphere scatters streams of fast neutrons, and the shock wave is stronger at large distances.

What about the cobalt bomb?

No, son, this is fantastic. Officially, no country has cobalt bombs. Theoretically, this is a thermonuclear bomb with a cobalt shell, which ensures strong radioactive contamination of the area even with a relatively weak nuclear explosion. 510 tons of cobalt can infect the entire surface of the Earth and destroy all life on the planet. Physicist Leo Szilard , who described this hypothetical design in 1950, called it the "Doomsday Machine".

What's cooler: a nuclear bomb or a thermonuclear one?

Full-scale model of "Tsar Bomba"

The hydrogen bomb is much more advanced and technologically advanced than the atomic one. Its explosive power far exceeds that of an atomic one and is limited only by the number of available components. In a thermonuclear reaction, much more energy is released for each nucleon (the so-called constituent nuclei, protons and neutrons) than in a nuclear reaction. For example, the fission of a uranium nucleus produces 0.9 MeV (megaelectronvolt) per nucleon, and the fusion of a helium nucleus from hydrogen nuclei releases an energy of 6 MeV.

Like bombs deliverto the goal?

At first they were dropped from airplanes, but air defense systems were constantly improving, and delivering nuclear weapons in this way turned out to be unwise. With the growth of missile production, all rights to deliver nuclear weapons were transferred to ballistic and cruise missiles of various bases. Therefore, a bomb now means not a bomb, but a warhead.

It is believed that the North Korean hydrogen bomb is too large to be mounted on a rocket - so if the DPRK decides to carry out the threat, it will be carried by ship to the explosion site.

What are the consequences of a nuclear war?

Hiroshima and Nagasaki are only a small part of the possible apocalypse. ​For example, the “nuclear winter” hypothesis is known, which was put forward by the American astrophysicist Carl Sagan and the Soviet geophysicist Georgy Golitsyn. It is assumed that the explosion of several nuclear warheads (not in the desert or water, but in populated areas) will cause many fires, and a large amount of smoke and soot will spill into the atmosphere, which will lead to global cooling. The hypothesis has been criticized by comparing the effect to volcanic activity, which has little effect on climate. In addition, some scientists note that global warming is more likely to occur than cooling - although both sides hope that we will never know.

Are nuclear weapons allowed?

After the arms race in the 20th century, countries came to their senses and decided to limit the use of nuclear weapons. The UN adopted treaties on the non-proliferation of nuclear weapons and the ban on nuclear tests (the latter was not signed by the young nuclear powers India, Pakistan, and the DPRK). In July 2017, a new treaty on the prohibition of nuclear weapons was adopted.

“Each State Party undertakes never under any circumstances to develop, test, produce, manufacture, otherwise acquire, possess or stockpile nuclear weapons or other nuclear explosive devices,” states the first article of the treaty. .

However, the document will not come into force until 50 states ratify it.

But this is something we often don’t know. And why does a nuclear bomb explode, too...

Let's start from afar. Every atom has a nucleus, and the nucleus consists of protons and neutrons - perhaps everyone knows this. In the same way, everyone saw the periodic table. But why are the chemical elements in it placed this way and not otherwise? Certainly not because Mendeleev wanted it that way. The atomic number of each element in the table indicates how many protons are in the nucleus of that element's atom. In other words, iron is number 26 in the table because there are 26 protons in an iron atom. And if there are not 26 of them, it is no longer iron.

But there can be different numbers of neutrons in the nuclei of the same element, which means that the mass of the nuclei can be different. Atoms of the same element with different masses are called isotopes. Uranium has several such isotopes: the most common in nature is uranium-238 (its nucleus has 92 protons and 146 neutrons, totaling 238). It is radioactive, but you cannot make a nuclear bomb from it. But the isotope uranium-235, a small amount of which is found in uranium ores, is suitable for a nuclear charge.

The reader may have come across the expressions “enriched uranium” and “depleted uranium”. Enriched uranium contains more uranium-235 than natural uranium; in a depleted state, correspondingly, less. Enriched uranium can be used to produce plutonium, another element suitable for a nuclear bomb (it is almost never found in nature). How uranium is enriched and how plutonium is obtained from it is a topic for a separate discussion.

So why does a nuclear bomb explode? The fact is that some heavy nuclei tend to decay if they are hit by a neutron. And you won’t have to wait long for a free neutron – there are a lot of them flying around. So, such a neutron hits the uranium-235 nucleus and thereby breaks it into “fragments”. This releases a few more neutrons. Can you guess what will happen if there are nuclei of the same element around? That's right, a chain reaction will occur. This is how it happens.

In a nuclear reactor, where uranium-235 is “dissolved” in the more stable uranium-238, an explosion does not occur under normal conditions. Most of the neutrons that fly out of decaying nuclei fly away into the milk, without finding the uranium-235 nuclei. In the reactor, the decay of nuclei occurs “sluggishly” (but this is enough for the reactor to provide energy). In a single piece of uranium-235, if it is of sufficient mass, neutrons will be guaranteed to break up the nuclei, the chain reaction will start as an avalanche, and... Stop! After all, if you make a piece of uranium-235 or plutonium with the mass required for an explosion, it will explode immediately. This is not the point.

What if you take two pieces of subcritical mass and push them against each other using a remote-controlled mechanism? For example, place both in a tube and attach a powder charge to one so that at the right moment one piece, like a projectile, is fired at the other. Here is the solution to the problem.

You can do it differently: take a spherical piece of plutonium and attach explosive charges over its entire surface. When these charges detonate on command from the outside, their explosion will compress the plutonium from all sides, compress it to a critical density, and a chain reaction will occur. However, accuracy and reliability are important here: all explosive charges must go off at the same time. If some of them work, and some don’t, or some work late, no nuclear explosion will result: the plutonium will not be compressed to a critical mass, but will dissipate in the air. Instead of a nuclear bomb, you will get a so-called “dirty” one.

This is what an implosion-type nuclear bomb looks like. The charges, which are supposed to create a directed explosion, are made in the form of polyhedra in order to cover the surface of the plutonium sphere as tightly as possible.

The first type of device was called a cannon device, the second type - an implosion device.
The "Little Boy" bomb dropped on Hiroshima had a uranium-235 charge and a cannon-type device. The Fat Man bomb, detonated over Nagasaki, carried a plutonium charge, and the explosive device was implosion. Nowadays, gun-type devices are almost never used; implosion ones are more complicated, but at the same time they allow you to regulate the mass of the nuclear charge and spend it more rationally. And plutonium has replaced uranium-235 as a nuclear explosive.

Quite a few years passed, and physicists offered the military an even more powerful bomb - a thermonuclear bomb, or, as it is also called, a hydrogen bomb. It turns out that hydrogen explodes more powerfully than plutonium?

Hydrogen is indeed explosive, but not that explosive. However, there is no “ordinary” hydrogen in a hydrogen bomb; it uses its isotopes – deuterium and tritium. The nucleus of “ordinary” hydrogen has one neutron, deuterium has two, and tritium has three.

In a nuclear bomb, the nuclei of a heavy element are divided into nuclei of lighter ones. In thermonuclear fusion, the reverse process occurs: light nuclei merge with each other into heavier ones. Deuterium and tritium nuclei, for example, combine to form helium nuclei (otherwise known as alpha particles), and the “extra” neutron is sent into “free flight.” This releases significantly more energy than during the decay of plutonium nuclei. By the way, this is exactly the process that takes place on the Sun.

However, the fusion reaction is possible only at ultra-high temperatures (which is why it is called thermonuclear). How to make deuterium and tritium react? Yes, it’s very simple: you need to use a nuclear bomb as a detonator!

Since deuterium and tritium are themselves stable, their charge in a thermonuclear bomb can be arbitrarily huge. This means that a thermonuclear bomb can be made incomparably more powerful than a “simple” nuclear one. The “Baby” dropped on Hiroshima had a TNT equivalent of within 18 kilotons, and the most powerful hydrogen bomb (the so-called “Tsar Bomba”, also known as “Kuzka’s Mother”) was already 58.6 megatons, more than 3255 times more powerful "Baby"!


The “mushroom” cloud from the Tsar Bomba rose to a height of 67 kilometers, and the blast wave circled the globe three times.

However, such gigantic power is clearly excessive. Having “played enough” with megaton bombs, military engineers and physicists took a different path - the path of miniaturization of nuclear weapons. In their conventional form, nuclear weapons can be dropped from strategic bombers like aerial bombs or launched from ballistic missiles; if you miniaturize them, you get a compact nuclear charge that does not destroy everything for kilometers around, and which can be placed on an artillery shell or an air-to-ground missile. Mobility will increase and the range of tasks to be solved will expand. In addition to strategic nuclear weapons, we will receive tactical ones.

A variety of delivery systems have been developed for tactical nuclear weapons - nuclear cannons, mortars, recoilless rifles (for example, the American Davy Crockett). The USSR even had a nuclear bullet project. True, it had to be abandoned - nuclear bullets were so unreliable, so complicated and expensive to manufacture and store that there was no point in them.

"Davy Crockett." A number of these nuclear weapons were in service with the US Armed Forces, and the West German Minister of Defense unsuccessfully sought to arm the Bundeswehr with them.

Speaking about small nuclear weapons, it is worth mentioning another type of nuclear weapon - the neutron bomb. The plutonium charge in it is small, but this is not necessary. If a thermonuclear bomb follows the path of increasing the force of the explosion, then a neutron bomb relies on another damaging factor - radiation. To enhance radiation, a neutron bomb contains a supply of beryllium isotope, which upon explosion produces a huge number of fast neutrons.

According to its creators, a neutron bomb should kill enemy personnel, but leave equipment intact, which can then be captured during an offensive. In practice, it turned out somewhat differently: irradiated equipment becomes unusable - anyone who dares to pilot it will very soon “earn” radiation sickness. This does not change the fact that a neutron bomb explosion is capable of hitting an enemy through tank armor; neutron ammunition was developed by the United States specifically as a weapon against Soviet tank formations. However, tank armor was soon developed that provided some kind of protection from the flow of fast neutrons.

Another type of nuclear weapon was invented in 1950, but never (as far as is known) produced. This is the so-called cobalt bomb - a nuclear charge with a cobalt shell. During the explosion, cobalt, irradiated by a stream of neutrons, becomes an extremely radioactive isotope and is scattered throughout the area, contaminating it. Just one such bomb of sufficient power could cover the entire globe with cobalt and destroy all of humanity. Fortunately, this project remained a project.

What can we say in conclusion? A nuclear bomb is a truly terrible weapon, and at the same time it (what a paradox!) helped maintain relative peace between the superpowers. If your enemy has nuclear weapons, you will think ten times before attacking him. No country with a nuclear arsenal has ever been attacked from outside, and there have been no wars between major states in the world since 1945. Let's hope there won't be any.

Atomic weapons - a device that receives enormous explosive power from the reactions of ATOMIC FISSION and NUCLEAR fusion.

About atomic weapons

Atomic weapons are the most powerful weapons today, in service with five countries: Russia, the USA, Great Britain, France and China. There are also a number of states that are more or less successfully developing atomic weapons, but their research is either not completed, or these countries do not have the necessary means of delivering weapons to the target. India, Pakistan, North Korea, Iraq, Iran have developed nuclear weapons at different levels, Germany, Israel, South Africa and Japan theoretically have the necessary capabilities to create nuclear weapons in a relatively short time.

It is difficult to overestimate the role of nuclear weapons. On the one hand, this is a powerful means of deterrence, on the other hand, it is the most effective tool for strengthening peace and preventing military conflicts between the powers that possess these weapons. 52 years have passed since the first use of the atomic bomb in Hiroshima. The world community has come close to realizing that a nuclear war will inevitably lead to a global environmental catastrophe, which will make the further existence of mankind impossible. Over the years, legal mechanisms have been created to defuse tensions and ease the confrontation between nuclear powers. For example, many agreements were signed to reduce the nuclear potential of powers, the Convention on the Non-Proliferation of Nuclear Weapons was signed, according to which possessor countries pledged not to transfer the technology for the production of these weapons to other countries, and countries that do not have nuclear weapons pledged not to take steps to development; Finally, quite recently, the superpowers agreed on a complete ban on nuclear testing. It is obvious that nuclear weapons are the most important instrument that has become the regulatory symbol of an entire era in the history of international relations and in the history of mankind.

Atomic weapons

ATOMIC WEAPON, a device that receives enormous explosive power from the reactions of ATOMIC FISSION and NUCLEAR fusion. The first nuclear weapons were used by the United States against the Japanese cities of Hiroshima and Nagasaki in August 1945. These atomic bombs consisted of two stable doctritic masses of URANIUM and PLUTONIUM, which upon violent collision caused the CRITICAL MASS to be exceeded, thereby provoking an uncontrolled CHAIN ​​REACTION of fission of atomic nuclei. Such explosions release enormous amounts of energy and harmful radiation: the explosive power can be equal to that of 200,000 tons of trinitrotoluene. The much more powerful hydrogen bomb (fusion bomb), first tested in 1952, consists of an atomic bomb that, when exploded, creates a temperature high enough to cause nuclear fusion in a nearby solid layer, usually lithium deterrite. The explosive power can be equal to that of several million tons (megatons) of trinitrotoluene. The area of ​​destruction caused by such bombs reaches large sizes: a 15 megaton bomb will explode all burning substances within 20 km. The third type of nuclear weapon, the neutron bomb, is a small hydrogen bomb, also called a high radiation weapon. It causes a weak explosion, which, however, is accompanied by an intense emission of high-speed NEUTRONS. The weakness of the explosion means that buildings are not damaged much. Neutrons cause serious radiation sickness in people within a certain radius of the explosion site, and kill everyone affected within a week.

Initially, the explosion of an atomic bomb (A) forms a fireball (1) with a temperature of millions of degrees Celsius and emits radiation (?). After a few minutes (B), the ball increases in volume and creates a shock wave with high pressure (3). The fireball rises (C), sucking up dust and debris, and forms a mushroom cloud (D), As the fireball increases in volume, it creates a powerful convection current (4), releasing hot radiation (5) and forming a cloud (6), When it explodes 15 megaton bomb destruction from the blast wave is complete (7) in a radius of 8 km, severe (8) in a radius of 15 km and noticeable (I) in a radius of 30 km Even at a distance of 20 km (10) all flammable substances explode, within two days after the bomb explodes, fallout continues to fall 300 km from the explosion with a radioactive dose of 300 roentgens. The accompanying photo shows how the explosion of a large nuclear weapon on the ground creates a huge mushroom cloud of radioactive dust and debris that can reach a height of several kilometers. Dangerous dust in the air is then freely transported by prevailing winds in any direction. Devastation covers a vast area.

Modern atomic bombs and shells

Radius of action

Depending on the power of the atomic charge, atomic bombs and shells are divided into calibers: small, medium and large . To obtain energy equal to the energy of the explosion of a small-caliber atomic bomb, you need to explode several thousand tons of TNT. The TNT equivalent of a medium-caliber atomic bomb is tens of thousands, and that of a large-caliber bomb is hundreds of thousands of tons of TNT. Thermonuclear (hydrogen) weapons can have even greater power; their TNT equivalent can reach millions and even tens of millions of tons. Atomic bombs, the TNT equivalent of which is 1-50 thousand tons, belong to the class of tactical atomic bombs and are intended to solve operational-tactical problems. Tactical weapons also include: artillery shells with an atomic charge with a power of 10–15 thousand tons and atomic charges (with a power of about 5–20 thousand tons) for anti-aircraft guided missiles and shells used to arm fighter aircraft. Atomic and hydrogen bombs with a yield of over 50 thousand tons are classified as strategic weapons.

It should be noted that such a classification of atomic weapons is only conditional, since in reality the consequences of the use of tactical atomic weapons can be no less than those experienced by the population of Hiroshima and Nagasaki, and even greater. It is now obvious that the explosion of just one hydrogen bomb is capable of causing such severe consequences over vast territories that tens of thousands of shells and bombs used in past world wars did not carry with them. And a few hydrogen bombs are quite enough to turn vast territories into desert zones.

Nuclear weapons are divided into 2 main types: atomic and hydrogen (thermonuclear). In atomic weapons, energy is released due to the fission reaction of the nuclei of atoms of the heavy elements uranium or plutonium. In a hydrogen weapon, energy is released by the formation (or fusion) of helium atom nuclei from hydrogen atoms.

Thermonuclear weapons

Modern thermonuclear weapons are strategic weapons that can be used by aviation to destroy the most important industrial and military facilities, and large cities as centers of civilization behind enemy lines. The most well-known type of thermonuclear weapon is thermonuclear (hydrogen) bombs, which can be delivered to the target by aircraft. Warheads of missiles for various purposes, including intercontinental ballistic missiles, can also be filled with thermonuclear charges. For the first time, such a missile was tested in the USSR back in 1957. Currently, the Strategic Missile Forces are armed with several types of missiles based on mobile launchers, silo launchers, and submarines.

Atomic bomb

The operation of thermonuclear weapons is based on the use of a thermonuclear reaction with hydrogen or its compounds. In these reactions, which occur at ultra-high temperatures and pressures, energy is released by the formation of helium nuclei from hydrogen nuclei, or from hydrogen and lithium nuclei. To form helium, mainly heavy hydrogen is used - deuterium, the nuclei of which have an unusual structure - one proton and one neutron. When deuterium is heated to temperatures of several tens of millions of degrees, its atom loses its electron shells during the first collisions with other atoms. As a result, the medium turns out to consist only of protons and electrons moving independently of them. The speed of thermal motion of particles reaches such values ​​that deuterium nuclei can come closer and, thanks to the action of powerful nuclear forces, combine with each other, forming helium nuclei. The result of this process is the release of energy.

The basic diagram of a hydrogen bomb is as follows. Deuterium and tritium in a liquid state are placed in a tank with a heat-proof shell, which serves to preserve deuterium and tritium in a very cool state for a long time (to maintain it from a liquid state of aggregation). The heat-proof shell may contain 3 layers consisting of a hard alloy, solid carbon dioxide and liquid nitrogen. An atomic charge is placed near a reservoir of hydrogen isotopes. When an atomic charge is detonated, hydrogen isotopes are heated to high temperatures, creating conditions for a thermonuclear reaction to occur and a hydrogen bomb to explode. However, in the process of creating hydrogen bombs, it was found that it was impractical to use hydrogen isotopes, since in this case the bomb would acquire too much weight (more than 60 tons), which is why it was impossible to even think about using such charges on strategic bombers, and especially in ballistic missiles of any range. The second problem faced by the developers of the hydrogen bomb was the radioactivity of tritium, which made its long-term storage impossible.

Study 2 addressed the above issues. Liquid isotopes of hydrogen were replaced by the solid chemical compound of deuterium with lithium-6. This made it possible to significantly reduce the size and weight of the hydrogen bomb. In addition, lithium hydride was used instead of tritium, which made it possible to place thermonuclear charges on fighter bombers and ballistic missiles.

The creation of the hydrogen bomb did not mark the end of the development of thermonuclear weapons, more and more new samples appeared, the hydrogen-uranium bomb was created, as well as some of its varieties - heavy-duty and, conversely, small-caliber bombs. The last stage in the improvement of thermonuclear weapons was the creation of the so-called “clean” hydrogen bomb.

H-bomb

The first developments of this modification of the thermonuclear bomb appeared back in 1957, in the wake of US propaganda statements about the creation of some kind of “humane” thermonuclear weapon that would not cause as much harm to future generations as a conventional thermonuclear bomb. There was some truth in the claims to “humaneness.” Although the destructive power of the bomb was not less, at the same time it could be detonated so that strontium-90, which in a normal hydrogen explosion poisons the earth's atmosphere for a long time, would not spread. Everything within the range of such a bomb will be destroyed, but the danger to living organisms that are far from the explosion, as well as to future generations, will be reduced. However, these statements were refuted by scientists, who recalled that explosions of atomic or hydrogen bombs produce a large amount of radioactive dust, which rises with a powerful air flow to a height of 30 km, and then gradually settles to the ground over a large area, contaminating it. Research conducted by scientists shows that it will take 4 to 7 years for half of this dust to fall to the ground.

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