Classification of nuclear weapons. Nuclear explosion: description, classification Classification of nuclear explosions by power

The power of a nuclear explosion

1) its energy characteristic, usually expressed in TNT equivalent. It is caused by the mechanical and thermal effects of the explosion, as well as by the energy of instantaneous neutron and gamma radiation. According to the power of the explosion, nuclear munitions are conditionally divided into ultra-small (up to 1 thousand tons), small (from 1 to 10 thousand tons), medium (from 10 to 100 thousand tons), large (from 100 thousand to 1 million tons). ) and super-large (from 1 million tons and more);

2) quantitative characteristic of the explosion energy of a nuclear weapon, usually expressed in TNT equivalent. The power of a nuclear explosion includes the energy that determines the development of the mechanical and thermal effects of the explosion, and the energy of prompt neutron and gamma radiation. The energy of radioactive decay of fission products is not taken into account. A nuclear explosion of 1 kg of uranium-235 or plutonium-239 with complete fission of all nuclei is equivalent in terms of the released energy to a chemical explosion of 20,000 tons of TNT.

Edwart. Glossary of terms of the Ministry of Emergency Situations, 2010

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Nuclear weapon

Nuclear weapons - a set of nuclear weapons, their means of delivery to the target and controls. Refers to weapons of mass destruction (along with biological and chemical weapons). A nuclear weapon is an explosive device that uses nuclear energy - energy released as a result of an avalanche-like nuclear chain reaction of fission of heavy nuclei and / or a thermonuclear fusion reaction of light nuclei.

The action of a nuclear weapon is based on the use of the energy of an explosion of a nuclear explosive device, released as a result of an uncontrolled avalanche-like chain reaction of fission of heavy nuclei and / or a thermonuclear fusion reaction.

Nuclear explosions can be of the following types:

air - in the troposphere

high-altitude - in the upper atmosphere and near planetary space

space - in deep circumplanetary space and any other area of ​​​​outer space

ground explosion - near the ground

underground explosion (under the surface of the earth)

surface (near the surface of the water)

underwater (under water)

The damaging factors of a nuclear explosion:

shock wave

light radiation

penetrating radiation

radioactive contamination

electromagnetic pulse (EMP)

The ratio of the power of the impact of various damaging factors depends on the specific physics of a nuclear explosion. For example, a thermonuclear explosion is characterized by stronger than the so-called. atomic explosion light radiation, gamma-ray component of penetrating radiation, but much weaker corpuscular component of penetrating radiation and radioactive contamination of the area.

People directly exposed to the damaging factors of a nuclear explosion, in addition to physical damage, which are often fatal to humans, experience a powerful psychological impact from the horrifying picture of the explosion and destruction. An electromagnetic pulse (EMP) does not directly affect living organisms, but it can disrupt the operation of electronic equipment (tube electronics and photonic equipment are relatively insensitive to EMP).

Classification of nuclear weapons

All nuclear weapons can be divided into two main categories:

"atomic" - single-phase or single-stage explosive devices in which the main energy output comes from the nuclear fission reaction of heavy nuclei (uranium-235 or plutonium) with the formation of lighter elements

thermonuclear (also "hydrogen") - two-phase or two-stage explosive devices in which two physical processes sequentially develop, localized in different areas of space: in the first stage, the main source of energy is the fission reaction of heavy nuclei, and in the second, fission and thermonuclear fusion reactions are used in various proportions, depending on the type and setting of the ammunition

The power of a nuclear charge is measured in TNT equivalent - the amount of trinitrotoluene that must be exploded to obtain the same energy. It is usually expressed in kilotons (kt) and megatons (Mt). The TNT equivalent is conditional: firstly, the distribution of the energy of a nuclear explosion over various damaging factors depends significantly on the type of ammunition, and, in any case, is very different from a chemical explosion. Secondly, it is simply impossible to achieve complete combustion of an appropriate amount of chemical explosive.

It is customary to divide nuclear weapons by power into five groups:

ultra-small (less than 1 kt)

small (1 - 10 ct)

medium (10 - 100 kt)

large (high power) (100 kt - 1 Mt)

super-large (extra-high power) (over 1 Mt)

Options for the detonation of nuclear weapons

cannon scheme

The "cannon scheme" was used in some models of first generation nuclear weapons. The essence of the cannon scheme is to shoot with a charge of gunpowder one block of fissile material of subcritical mass ("bullet") into another - motionless ("target").

A classic example of a cannon scheme is the Little Boy bomb dropped on Hiroshima on August 6, 1945.

implosive scheme

The implosive detonation scheme uses the compression of fissile material by a focused shock wave created by an explosion of chemical explosives. To focus the shock wave, so-called explosive lenses are used, and the explosion is carried out simultaneously at many points with high accuracy. The formation of a converging shock wave was provided 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 (see animation). The creation of such a system for the location of explosives and detonation was at one time one of the most difficult and time-consuming tasks. To solve it, it was necessary to perform a gigantic amount of complex calculations in hydro- and gas dynamics.

The second of the used atomic bombs - "Fat Man" - dropped on Nagasaki on August 9, 1945, was executed according to the same scheme.

Explosive action, based on the use of intranuclear energy released during chain reactions of fission of heavy nuclei of some isotopes of uranium and plutonium or during thermonuclear reactions of fusion of hydrogen isotopes (deuterium and tritium) into heavier ones, for example, helium isogon nuclei. In thermonuclear reactions, energy is released 5 times more than in fission reactions (with the same mass of nuclei).

Nuclear weapons include various nuclear weapons, means of delivering them to the target (carriers) and controls.

Depending on the method of obtaining nuclear energy, ammunition is divided into nuclear (on fission reactions), thermonuclear (on fusion reactions), combined (in which energy is obtained according to the “fission-fusion-fission” scheme). The power of nuclear weapons is measured in TNT equivalent, t. a mass of explosive TNT, the explosion of which releases such an amount of energy as the explosion of a given nuclear bosiripas. TNT equivalent is measured in tons, kilotons (kt), megatons (Mt).

Ammunition with a capacity of up to 100 kt is designed on fission reactions, from 100 to 1000 kt (1 Mt) on fusion reactions. Combined munitions can be over 1 Mt. By power, nuclear weapons are divided into ultra-small (up to 1 kg), small (1-10 kt), medium (10-100 kt) and extra-large (more than 1 Mt).

Depending on the purpose of using nuclear weapons, nuclear explosions can be high-altitude (above 10 km), air (not more than 10 km), ground (surface), underground (underwater).

Damaging factors of a nuclear explosion

The main damaging factors of a nuclear explosion are: a shock wave, light radiation from a nuclear explosion, penetrating radiation, radioactive contamination of the area and an electromagnetic pulse.

shock wave

Shockwave (SW)- a region of sharply compressed air, spreading in all directions from the center of the explosion at supersonic speed.

Hot vapors and gases, trying to expand, produce a sharp blow to the surrounding layers of air, compress them to high pressures and densities and heat up to high temperatures (several tens of thousands of degrees). This layer of compressed air represents the shock wave. The front boundary of the compressed air layer is called the front of the shock wave. The SW front is followed by an area of ​​rarefaction, where the pressure is below atmospheric. Near the center of the explosion, the velocity of SW propagation is several times higher than the speed of sound. As the distance from the explosion increases, the wave propagation speed decreases rapidly. At large distances, its speed approaches the speed of sound in air.

The shock wave of an ammunition of medium power passes: the first kilometer in 1.4 s; the second - in 4 s; the fifth - in 12 s.

The damaging effect of hydrocarbons on people, equipment, buildings and structures is characterized by: velocity pressure; overpressure in the shock front and the time of its impact on the object (compression phase).

The impact of HC on people can be direct and indirect. With direct exposure, the cause of injury is an instantaneous increase in air pressure, which is perceived as a sharp blow leading to fractures, damage to internal organs, and rupture of blood vessels. With indirect impact, people are amazed by flying debris of buildings and structures, stones, trees, broken glass and other objects. Indirect impact reaches 80% of all lesions.

With an overpressure of 20-40 kPa (0.2-0.4 kgf / cm 2), unprotected people can get light injuries (light bruises and concussions). The impact of SW with excess pressure of 40-60 kPa leads to lesions of moderate severity: loss of consciousness, damage to the hearing organs, severe dislocations of the limbs, damage to internal organs. Extremely severe lesions, often fatal, are observed at excess pressure over 100 kPa.

The degree of damage by a shock wave to various objects depends on the power and type of explosion, the mechanical strength (stability of the object), as well as on the distance at which the explosion occurred, the terrain and the position of objects on the ground.

To protect against the impact of hydrocarbons, one should use: trenches, cracks and trenches, which reduce its effect by 1.5-2 times; dugouts - 2-3 times; shelters - 3-5 times; basements of houses (buildings); terrain (forest, ravines, hollows, etc.).

light emission

light emission is a stream of radiant energy, including ultraviolet, visible and infrared rays.

Its source is a luminous area formed by the hot products of the explosion and hot air. Light radiation propagates almost instantly and lasts, depending on the power of a nuclear explosion, up to 20 s. However, its strength is such that, despite its short duration, it can cause skin (skin) burns, damage (permanent or temporary) to the organs of vision of people, and ignition of combustible materials of objects. At the moment of formation of a luminous region, the temperature on its surface reaches tens of thousands of degrees. The main damaging factor of light radiation is a light pulse.

Light pulse - the amount of energy in calories falling per unit area of ​​the surface perpendicular to the direction of radiation, for the entire duration of the glow.

Attenuation of light radiation is possible due to its screening by atmospheric clouds, uneven terrain, vegetation and local objects, snowfall or smoke. Thus, a thick layer attenuates the light pulse by A-9 times, a rare layer - by 2-4 times, and smoke (aerosol) screens - by 10 times.

To protect the population from light radiation, it is necessary to use protective structures, basements of houses and buildings, and the protective properties of the terrain. Any obstruction capable of creating a shadow protects against the direct action of light radiation and eliminates burns.

penetrating radiation

penetrating radiation- notes of gamma rays and neutrons emitted from the zone of a nuclear explosion. The time of its action is 10-15 s, the range is 2-3 km from the center of the explosion.

In conventional nuclear explosions, neutrons make up approximately 30%, in the explosion of neutron ammunition - 70-80% of the y-radiation.

The damaging effect of penetrating radiation is based on the ionization of cells (molecules) of a living organism, leading to death. Neutrons, in addition, interact with the nuclei of atoms of certain materials and can cause induced activity in metals and technology.

The main parameter characterizing the penetrating radiation is: for γ-radiation - the dose and dose rate of radiation, and for neutrons - the flux and flux density.

Permissible exposure doses for the population in wartime: single - within 4 days 50 R; multiple - within 10-30 days 100 R; during the quarter - 200 R; during the year - 300 R.

As a result of the passage of radiation through the materials of the environment, the intensity of the radiation decreases. The weakening effect is usually characterized by a layer of half attenuation, i.e. with. such a thickness of the material, passing through which the radiation is reduced by 2 times. For example, the intensity of the y-rays is reduced by 2 times: steel 2.8 cm thick, concrete - 10 cm, soil - 14 cm, wood - 30 cm.

Protective structures are used as protection against penetrating radiation, which weaken its impact from 200 to 5000 times. A pound layer of 1.5 m protects almost completely from penetrating radiation.

Radioactive contamination (contamination)

Radioactive contamination of the air, terrain, water area and objects located on them occurs as a result of the fallout of radioactive substances (RS) from the cloud of a nuclear explosion.

At a temperature of about 1700 ° C, the glow of the luminous region of a nuclear explosion stops and it turns into a dark cloud, to which a dust column rises (therefore, the cloud has a mushroom shape). This cloud moves in the direction of the wind, and RVs fall out of it.

The sources of RS in the cloud are the fission products of nuclear fuel (uranium, plutonium), the unreacted part of the nuclear fuel and radioactive isotopes formed as a result of the action of neutrons on the ground (induced activity). These RVs, being on contaminated objects, decay, emitting ionizing radiation, which in fact are the damaging factor.

The parameters of radioactive contamination are the radiation dose (according to the impact on people) and the radiation dose rate - the level of radiation (according to the degree of contamination of the area and various objects). These parameters are a quantitative characteristic of damaging factors: radioactive contamination during an accident with the release of radioactive substances, as well as radioactive contamination and penetrating radiation during a nuclear explosion.

On the terrain that has undergone radioactive contamination during a nuclear explosion, two sections are formed: the area of ​​​​the explosion and the trace of the cloud.

According to the degree of danger, the contaminated area along the trail of the explosion cloud is usually divided into four zones (Fig. 1):

Zone A- zone of moderate infection. It is characterized by a dose of radiation until the complete decay of radioactive substances at the outer boundary of the zone 40 rad and at the inner - 400 rad. The area of ​​zone A is 70-80% of the area of ​​the entire footprint.

Zone B- zone of severe infection. The radiation doses at the boundaries are 400 rad and 1200 rad, respectively. The area of ​​zone B is approximately 10% of the area of ​​the radioactive trace.

Zone B— zone of dangerous infection. It is characterized by radiation doses at the borders of 1200 rad and 4000 rad.

Zone G- zone of extremely dangerous infection. Doses at the borders of 4000 rad and 7000 rad.

Rice. 1. Scheme of radioactive contamination of the area in the area of ​​a nuclear explosion and in the wake of the movement of the cloud

Radiation levels at the outer boundaries of these zones 1 hour after the explosion are 8, 80, 240, 800 rad/h, respectively.

Most of the radioactive fallout, causing radioactive contamination of the area, falls out of the cloud 10-20 hours after a nuclear explosion.

electromagnetic pulse

Electromagnetic pulse (EMP) is a set of electric and magnetic fields resulting from the ionization of the atoms of the medium under the influence of gamma radiation. Its duration is a few milliseconds.

The main parameters of EMR are the currents and voltages induced in wires and cable lines, which can lead to damage and disable electronic equipment, and sometimes to damage to people working with the equipment.

During ground and air explosions, the damaging effect of an electromagnetic pulse is observed at a distance of several kilometers from the center of a nuclear explosion.

The most effective protection against an electromagnetic pulse is the shielding of power supply and control lines, as well as radio and electrical equipment.

The situation that develops during the use of nuclear weapons in the centers of destruction.

The focus of nuclear destruction is the territory within which, as a result of the use of nuclear weapons, mass destruction and death of people, farm animals and plants, destruction and damage to buildings and structures, utility and energy and technological networks and lines, transport communications and other objects occurred.

Zones of the focus of a nuclear explosion

To determine the nature of possible destruction, the volume and conditions for carrying out rescue and other urgent work, the nuclear lesion site is conditionally divided into four zones: complete, strong, medium and weak destruction.

Zone of complete destruction has an overpressure at the front of the shock wave of 50 kPa at the border and is characterized by massive irretrievable losses among the unprotected population (up to 100%), complete destruction of buildings and structures, destruction and damage to utility and energy and technological networks and lines, as well as parts of civil defense shelters, the formation of solid blockages in settlements. The forest is completely destroyed.

Zone of severe damage with overpressure at the shock wave front from 30 to 50 kPa is characterized by: massive irretrievable losses (up to 90%) among the unprotected population, complete and severe destruction of buildings and structures, damage to utility and energy and technological networks and lines, the formation of local and continuous blockages in settlements and forests, the preservation of shelters and the majority of anti-radiation shelters of the basement type.

Medium damage zone with an excess pressure of 20 to 30 kPa is characterized by irretrievable losses among the population (up to 20%), medium and severe destruction of buildings and structures, the formation of local and focal blockages, continuous fires, the preservation of utility networks, shelters and most of the anti-radiation shelters.

Zone of weak damage with excess pressure from 10 to 20 kPa is characterized by weak and medium destruction of buildings and structures.

The focus of the lesion but the number of dead and injured can be commensurate with or exceed the lesion in an earthquake. So, during the bombing (bomb power up to 20 kt) of the city of Hiroshima on August 6, 1945, most of it (60%) was destroyed, and the death toll amounted to 140,000 people.

The personnel of economic facilities and the population entering the zones of radioactive contamination are exposed to ionizing radiation, which causes radiation sickness. The severity of the disease depends on the dose of radiation (irradiation) received. The dependence of the degree of radiation sickness on the magnitude of the radiation dose is given in Table. 2.

Table 2. Dependence of the degree of radiation sickness on the magnitude of the radiation dose

Under the conditions of hostilities with the use of nuclear weapons, vast territories may turn out to be in the zones of radioactive contamination, and exposure of people may take on a mass character. In order to exclude overexposure of the personnel of facilities and the population in such conditions and to increase the stability of the functioning of objects of the national economy under conditions of radioactive contamination in wartime, permissible exposure doses are established. They make up:

• with a single irradiation (up to 4 days) - 50 rad;
• repeated irradiation: a) up to 30 days - 100 rad; b) 90 days - 200 rad;
• systematic exposure (during the year) 300 rad.

Caused by the use of nuclear weapons, the most complex. To eliminate them, disproportionately greater forces and means are needed than in the elimination of emergency situations in peacetime.

At the beginning of the 20th century, thanks to the efforts of Albert Einstein, mankind first learned that at the atomic level, from a small amount of matter, under certain conditions, a huge amount of energy can be obtained. In the 1930s, work in this direction was continued by the German nuclear physicist Otto Hahn, the Englishman Robert Frisch, and the Frenchman Joliot-Curie. It was they who managed in practice to track the results of the fission of the nuclei of atoms of radioactive chemical elements. The chain reaction process simulated in laboratories confirmed Einstein's theory about the ability of a substance in small quantities to release a large amount of energy. Under such conditions, the physics of a nuclear explosion was born - a science that cast doubt on the possibility of the further existence of terrestrial civilization.

The birth of nuclear weapons

Back in 1939, the Frenchman Joliot-Curie realized that exposure to uranium nuclei under certain conditions could lead to an explosive reaction of enormous power. As a result of a nuclear chain reaction, spontaneous exponential fission of uranium nuclei begins, and a huge amount of energy is released. In an instant, the radioactive substance exploded, and the resulting explosion had a huge damaging effect. As a result of the experiments, it became clear that uranium (U235) can be turned from a chemical element into a powerful explosive.

For peaceful purposes, during the operation of a nuclear reactor, the process of nuclear fission of radioactive components is calm and controlled. In a nuclear explosion, the main difference is that a huge amount of energy is released instantly and this continues until the supply of radioactive explosives runs out. For the first time, a person learned about the combat capabilities of the new explosive on July 16, 1945. At the time when the final meeting of the Heads of State of the victors of the war with Germany was taking place in Potsdam, the first test of an atomic warhead took place at the test site in Alamogordo, New Mexico. The parameters of the first nuclear explosion were quite modest. The power of the atomic charge in TNT equivalent was equal to the mass of trinitrotoluene in 21 kilotons, but the force of the explosion and its impact on surrounding objects made an indelible impression on everyone who watched the tests.

Explosion of the first atomic bomb

At first, everyone saw a bright luminous dot, which was visible at a distance of 290 km. from the test site. At the same time, the sound from the explosion was heard within a radius of 160 km. At the place where the nuclear explosive device was installed, a huge crater formed. The funnel from a nuclear explosion reached a depth of more than 20 meters, with an outer diameter of 70 m. On the territory of the test site within a radius of 300-400 meters from the epicenter, the earth's surface was a lifeless lunar surface.

It is interesting to cite the recorded impressions of the participants in the first test of the atomic bomb. “The surrounding air became denser, its temperature instantly rose. Literally a minute later, a huge shock wave swept through the area. At the location of the charge, a huge fireball is formed, after which a mushroom-shaped nuclear explosion cloud began to form in its place. A column of smoke and dust, crowned with a massive nuclear mushroom head, rose to a height of 12 km. Everyone present in the shelter was struck by the scale of the explosion. No one could have imagined the power and strength we faced, ”wrote the head of the Manhattan Project, Leslie Groves, later.

No one, before or since, had at his disposal a weapon of such enormous power. This despite the fact that at that time scientists and the military did not yet have an idea about all the damaging factors of the new weapon. Only the visible main damaging factors of a nuclear explosion were taken into account, such as:

• shock wave of a nuclear explosion;
• light and thermal radiation of a nuclear explosion.

The fact that penetrating radiation and subsequent radioactive contamination during a nuclear explosion is fatal for all living things did not yet have a clear idea. It turned out that these two factors after a nuclear explosion will subsequently become the most dangerous for a person. The zone of complete destruction and devastation is quite small in area in comparison with the zone of contamination of the area by the products of radiation decay. An infected area can have an area of ​​hundreds of kilometers. To the exposure received in the first minutes after the explosion, and to the level of radiation subsequently, contamination of vast territories with radioactive fallout is added. The scale of the catastrophe becomes apocalyptic.

Only later, much later, when atomic bombs were used for military purposes, it became clear how powerful the new weapon was and how severe the consequences of the use of a nuclear bomb would be for people.

The mechanism of atomic charge and the principle of operation

If you do not go into detailed descriptions and technology for creating an atomic bomb, you can briefly describe a nuclear charge in just three phrases:

• there is a subcritical mass of radioactive material (uranium U235 or plutonium Pu239);
• creation of certain conditions for the start of a chain reaction of nuclear fission of radioactive elements (detonation);
• creation of a critical mass of fissile material.

The whole mechanism can be depicted in a simple and understandable drawing, where all parts and details are in strong and close interaction with each other. As a result of the detonation of a chemical or electrical detonator, a detonation spherical wave is launched, compressing the fissile material to a critical mass. The nuclear charge is a multilayer structure. Uranium or plutonium is used as the main explosive. A certain amount of TNT or RDX can serve as a detonator. Further, the compression process becomes uncontrollable.

The speed of the ongoing processes is enormous and comparable to the speed of light. The time interval from the start of detonation to the start of an irreversible chain reaction takes no more than 10-8 s. In other words, it takes only 10-7 seconds to power 1 kg of enriched uranium. This value denotes the time of a nuclear explosion. The reaction of thermonuclear fusion, which is the basis of a thermonuclear bomb, proceeds with a similar speed, with the difference that a nuclear charge sets in motion an even more powerful one - a thermonuclear charge. A thermonuclear bomb has a different principle of operation. Here we are dealing with the reaction of the synthesis of light elements into heavier ones, as a result of which, again, a huge amount of energy is released.

In the process of fission of uranium or plutonium nuclei, a huge amount of energy is generated. At the center of a nuclear explosion, the temperature is 107 Kelvin. Under such conditions, a colossal pressure arises - 1000 atm. Atoms of fissile matter turn into plasma, which becomes the main result of the chain reaction. During the accident at the 4th reactor of the Chernobyl nuclear power plant, there was no nuclear explosion, since the fission of radioactive fuel was carried out slowly and was accompanied only by intense heat release.

The high speed of the processes occurring inside the charge leads to a rapid jump in temperature and an increase in pressure. It is these components that form the nature, factors and power of a nuclear explosion.

Types and types of nuclear explosions

The chain reaction that has started can no longer be stopped. In thousandths of a second, a nuclear charge, consisting of radioactive elements, turns into a plasma clot, torn apart by high pressure. A successive chain of a number of other factors begins that have a damaging effect on the environment, infrastructure facilities and living organisms. The only difference in damage is that a small nuclear bomb (10-30 kilotons) causes less destruction and less severe consequences than a large nuclear explosion with a yield of 100 more megatons.

The damaging factors depend not only on the power of the charge. To assess the consequences, the conditions for detonating a nuclear weapon are important, which type of nuclear explosion is observed in this case. Undermining the charge can be carried out on the surface of the earth, underground or under water, according to the conditions of use, we are dealing with the following types:

• air nuclear explosions carried out at certain heights above the earth's surface;
• high-altitude explosions carried out in the planet's atmosphere at altitudes above 10 km;
• land (surface) nuclear explosions carried out directly above the surface of the earth or above the water surface;
• underground or underwater explosions carried out in the surface thickness of the earth's crust or under water, at a certain depth.

In each individual case, certain damaging factors have their own strength, intensity and characteristics of the action, leading to certain results. In one case, a targeted destruction of the target occurs with minimal destruction and radioactive contamination of the territory. In other cases, one has to deal with large-scale devastation of the area and the destruction of objects, instant destruction of all life occurs, and strong radioactive contamination of vast territories is observed.

An air nuclear explosion, for example, differs from a ground-based detonation method in that the fireball does not come into contact with the earth's surface. In such an explosion, dust and other small fragments are combined into a dust column that exists separately from the explosion cloud. Accordingly, the area of ​​damage also depends on the height of the explosion. Such explosions can be high and low.

The first tests of atomic warheads both in the USA and in the USSR were mainly of three types, ground, air and underwater. Only after the Treaty on the Limitation of Nuclear Tests came into force, nuclear explosions in the USSR, in the USA, in France, in China and in Great Britain began to be carried out only underground. This made it possible to minimize environmental pollution with radioactive products, to reduce the area of ​​exclusion zones that arose near military training grounds.

The most powerful nuclear explosion in the history of nuclear testing took place on October 30, 1961 in the Soviet Union. A bomb with a total weight of 26 tons and a capacity of 53 megatons was dropped in the area of ​​the Novaya Zemlya archipelago from a Tu-95 strategic bomber. This is an example of a typical high air burst, as the explosion occurred at an altitude of 4 km.

It should be noted that the detonation of a nuclear warhead in the air is characterized by a strong effect of light radiation and penetrating radiation. The flash of a nuclear explosion is clearly visible tens and hundreds of kilometers from the epicenter. In addition to powerful light radiation and a strong shock wave diverging around 3600, an air explosion becomes a source of strong electromagnetic disturbance. An electromagnetic pulse generated during an air nuclear explosion within a radius of 100-500 km. able to disable the entire ground electrical infrastructure and electronics.

A striking example of a low air burst was the August 1945 atomic bombing of the Japanese cities of Hiroshima and Nagasaki. Bombs "Fat Man" and "Baby" worked at an altitude of half a kilometer, thereby covering almost the entire territory of these cities with a nuclear explosion. Most of the inhabitants of Hiroshima died in the first seconds after the explosion, as a result of exposure to intense light, heat and gamma radiation. The shock wave completely destroyed the city buildings. In the case of the bombing of the city of Nagasaki, the effect of the explosion was weakened by the features of the relief. The hilly terrain allowed some areas of the city to avoid the direct action of light rays, and reduced the impact force of the blast wave. But during such an explosion, extensive radioactive contamination of the area was observed, which subsequently led to serious consequences for the population of the destroyed city.

Low and high air bursts are the most common modern means of weapons of mass destruction. Such charges are used to destroy the accumulation of troops and equipment, cities and ground infrastructure.

A high-altitude nuclear explosion differs in the method of application and the nature of the action. The detonation of a nuclear weapon is carried out at an altitude of more than 10 km, in the stratosphere. With such an explosion, a bright sun-like flash of large diameter is observed high in the sky. Instead of clouds of dust and smoke, a cloud soon forms at the site of the explosion, consisting of molecules of hydrogen, carbon dioxide and nitrogen evaporated under the influence of high temperatures.

In this case, the main damaging factors are the shock wave, light radiation, penetrating radiation and EMP of a nuclear explosion. The higher the charge detonation height, the lower the shock wave strength. Radiation and light emission, on the contrary, only increase with increasing altitude. Due to the absence of significant movement of air masses at high altitudes, radioactive contamination of territories in this case is practically reduced to zero. Explosions at high altitudes, made within the ionosphere, disrupt the propagation of radio waves in the ultrasonic range.

Such explosions are mainly aimed at destroying high-flying targets. These can be reconnaissance aircraft, cruise missiles, strategic missile warheads, artificial satellites and other space attack weapons.

A ground-based nuclear explosion is a completely different phenomenon in military tactics and strategy. Here, a certain area of ​​the earth's surface is directly affected. Undermining a warhead can be carried out over an object or over water. The first tests of atomic weapons in the United States and in the USSR took place in this form.

A distinctive feature of this type of nuclear explosion is the presence of a pronounced mushroom cloud, which is formed due to the huge volumes of soil and rock particles raised by the explosion. At the very first moment, a luminous hemisphere is formed at the site of the explosion, with its lower edge touching the surface of the earth. During a contact detonation, a funnel is formed at the epicenter of the explosion, where the nuclear charge exploded. The depth and diameter of the funnel depends on the power of the explosion itself. When using small tactical ammunition, the diameter of the funnel can reach two or three tens of meters. When a nuclear bomb is detonated with high power, the dimensions of the crater often reach hundreds of meters.

The presence of a powerful mud and dust cloud contributes to the fact that the bulk of the radioactive products of the explosion falls back to the surface, making it completely contaminated. Smaller dust particles enter the surface layer of the atmosphere and, together with the air masses, scatter over vast distances. If an atomic charge is blown up on the surface of the earth, the radioactive trace from the produced ground explosion can stretch for hundreds and thousands of kilometers. During the accident at the Chernobyl nuclear power plant, radioactive particles that entered the atmosphere fell out along with precipitation on the territory of the Scandinavian countries, which are located 1000 km from the disaster site.

Ground explosions can be carried out to destroy and destroy objects of great strength. Such explosions can also be used if the goal is to create a vast zone of radioactive contamination of the area. In this case, all five damaging factors of a nuclear explosion are in effect. Following the thermodynamic shock and light radiation, an electromagnetic impulse comes into play. The shock wave and penetrating radiation complete the destruction of the object and manpower within the radius of action. Finally, there is radioactive contamination. Unlike the ground-based method of detonation, a surface nuclear explosion lifts huge masses of water into the air, both in liquid form and in a vapor state. The destructive effect is achieved due to the impact of the air shock wave and the large excitement resulting from the explosion. The water raised into the air prevents the spread of light radiation and penetrating radiation. Due to the fact that water particles are much heavier and are a natural neutralizer of the activity of elements, the intensity of the spread of radioactive particles in the air space is negligible.

An underground explosion of a nuclear weapon is carried out at a certain depth. Unlike ground explosions, there is no glowing area here. All the huge impact force is taken by the earth rock. The shock wave diverges in the thickness of the earth, causing a local earthquake. The huge pressure created during the explosion forms a column of soil collapse, going to great depths. As a result of rock subsidence, a funnel is formed at the site of the explosion, the dimensions of which depend on the power of the charge and the depth of the explosion.

Such an explosion is not accompanied by a mushroom cloud. The column of dust that rose at the site of the detonation of the charge has a height of only a few tens of meters. The shock wave converted into seismic waves and local surface radioactive contamination are the main damaging factors in such explosions. As a rule, this type of detonation of a nuclear charge is of economic and applied importance. To date, most nuclear tests are carried out underground. In the 1970s and 1980s, national economic problems were solved in a similar way, using the colossal energy of a nuclear explosion to destroy mountain ranges and form artificial reservoirs.

On the map of nuclear test sites in Semipalatinsk (now the Republic of Kazakhstan) and in the state of Nevada (USA) there are a huge number of craters, traces of underground nuclear tests.

Underwater detonation of a nuclear charge is carried out at a given depth. In this case, there is no light flash during the explosion. A water column 200-500 meters high appears on the surface of the water at the place of explosion, which is crowned with a cloud of spray and steam. The formation of a shock wave occurs immediately after the explosion, causing disturbances in the water column. The main damaging factor of the explosion is the shock wave, which transforms into waves of great height. With the explosion of high-power charges, the height of the waves can reach 100 meters or more. In the future, a strong radioactive contamination is observed at the site of the explosion and in the adjacent territory.

Methods of protection against damaging factors of a nuclear explosion

As a result of the explosive reaction of a nuclear charge, a huge amount of thermal and light energy is generated, which can not only destroy and destroy inanimate objects, but also kill all living things over a large area. In the epicenter of the explosion and in its immediate vicinity, as a result of intense exposure to penetrating radiation, light, thermal radiation and shock waves, all living things die, military equipment is destroyed, buildings and structures are destroyed. With distance from the epicenter of the explosion and over time, the strength of the damaging factors decreases, giving way to the last destructive factor - radioactive contamination.

It is useless to seek salvation for those who have fallen into the epicenter of a nuclear apocalypse. Neither a strong bomb shelter nor personal protective equipment will save here. Injuries and burns received by a person in such situations are incompatible with life. The destruction of infrastructure facilities is total and cannot be restored. In turn, those who found themselves at a considerable distance from the explosion site can count on salvation using certain skills and special methods of protection.

The main damaging factor in a nuclear explosion is the shock wave. The area of ​​high pressure formed at the epicenter affects the air mass, creating a shock wave that propagates in all directions at supersonic speed.

The propagation speed of the blast wave is as follows:

• on flat terrain, the shock wave overcomes 1000 meters from the epicenter of the explosion in 2 seconds;
• at a distance of 2000 m from the epicenter, the shock wave will overtake you in 5 seconds;
• being at a distance of 3 km from the explosion, the shock wave should be expected in 8 seconds.

After the passage of the blast wave, an area of ​​low pressure arises. In an effort to fill the rarefied space, the air goes in the opposite direction. The created vacuum effect causes another wave of destruction. Seeing a flash, before the arrival of the blast wave, you can try to find shelter, reducing the effects of the impact of the shock wave.

Light and heat radiation at a great distance from the epicenter of the explosion lose their strength, so if a person managed to take cover at the sight of a flash, you can count on salvation. Much more terrible is penetrating radiation, which is a rapid stream of gamma rays and neutrons that propagate at the speed of light from the luminous area of ​​​​the explosion. The most powerful effect of penetrating radiation occurs in the first seconds after the explosion. While in shelter or shelter, there is a high probability of avoiding a direct hit of deadly gamma radiation. Penetrating radiation causes severe damage to living organisms, causing radiation sickness.

If all the above listed damaging factors of a nuclear explosion are of a short-term nature, then radioactive contamination is the most insidious and dangerous factor. Its destructive effect on the human body occurs gradually, over time. The amount of residual radiation and the intensity of radioactive contamination depends on the power of the explosion, terrain conditions and climatic factors. The radioactive products of the explosion, mixed with dust, small fragments and fragments, enter the surface air layer, after which, together with precipitation or independently, they fall to the surface of the earth. The radiation background in the zone of application of nuclear weapons is hundreds of times higher than the natural background radiation, creating a threat to all living things. Being in the territory subjected to a nuclear strike, contact with any objects should be avoided. Personal protective equipment and a dosimeter will reduce the likelihood of radioactive contamination.

A nuclear explosion is an uncontrolled process. During it, a large amount of radiant and thermal energy is released. This effect is the result of a nuclear chain reaction of fission or thermonuclear fusion, which takes place over a short time period.

Brief general information

A nuclear explosion in its origin can be a consequence of human activity on Earth or in near-Earth space. This phenomenon also in some cases arises as a result of natural processes on some types of stars. An artificial nuclear explosion is a powerful weapon. It is used to destroy large-scale ground and underground protected objects, accumulations of equipment and enemy troops. In addition, this weapon is used to completely destroy and suppress the opposing side as a tool that destroys small and large settlements with civilians living in them, as well as industrial strategic facilities.

Classification

As a rule, nuclear explosions are characterized by two features. These include the power of the charge and the location of the charge point directly at the disruptive moment. The projection of this point onto the earth's surface is called the epicenter of the explosion. Power is measured in TNT equivalent. This is the mass of trinitrotoluene, the detonation of which releases the same amount of energy as the estimated nuclear one. Most often, when measuring power, units such as one kiloton (1 kt) and one megaton (1 Mt) of TNT are used.

Phenomena

A nuclear explosion is accompanied by specific effects. They are characteristic only for this process and are not present in other explosions. The intensity of the phenomena that accompany a nuclear explosion depends on the location of the center. As an example, we can consider the case that was the most frequent before the ban on tests on the planet (under water, on earth, in the atmosphere) and, in fact, in space - an artificial chain reaction in the surface layer. After the detonation of the fusion or fission process in a very short time (about fractions of microseconds), a huge amount of thermal and radiant energy is released in a limited volume. The completion of the reaction, as a rule, is indicated by the expansion of the structure of the device and evaporation. These effects are due to the influence of elevated temperature (up to 107 K) and huge pressure (about 109 atm.) in the epicenter itself. From a great distance, visually, this phase is a very bright luminous point.

Electromagnetic radiation

Light pressure during the reaction begins to heat up and displace the surrounding air from the epicenter. The result is a fireball. Along with this, a pressure jump is formed between the compressed radiation and undisturbed air. This is due to the superiority of the speed of movement of the heating front over the sound speed in the environment. After the nuclear reaction enters the decay stage, the release of energy stops. The subsequent expansion is carried out due to the difference in pressures and temperatures in the zone of the fireball and the immediate surrounding air. It should be noted that the phenomena under consideration have nothing to do with the scientific research of the hero of the modern series (by the way, his name is the same as the famous physicist Glashow - Sheldon) "The Big Bang Theory".

penetrating radiation

Nuclear reactions are a source of electromagnetic radiation of various types. In particular, it manifests itself in a wide spectrum ranging from radio waves to gamma rays, atomic nuclei, neutrons, and fast electrons. The emerging radiation, called penetrating radiation, in turn produces certain consequences. They are peculiar only to a nuclear explosion. High-energy gamma quanta and neutrons in the process of interaction with the atoms that make up the surrounding matter undergo a transformation of their stable form into unstable radioactive isotopes with different periods and half-lives. As a result, the so-called induced radiation is formed. Together with fragments of atomic nuclei of fissile material or with products from thermonuclear fusion that remain from an explosive device, the resulting radioactive components rise into the atmosphere. Then they disperse over a fairly large area and form an infection on the ground. The unstable isotopes that accompany a nuclear explosion are in such a spectrum that the spread of radiation can continue for thousands of years, despite the fact that the radiation intensity decreases over time.

electromagnetic pulse

Formed from a nuclear explosion, high-energy gamma quanta in the process of passing through the environment ionize the atoms that make up its composition, knocking out electrons from them and giving them quite a lot of energy to carry out cascade ionization of other atoms (up to thirty thousand ionizations per gamma quantum). As a result, a "spot" of ions is formed under the epicenter, having a positive charge and surrounded by an enormous amount of electron gas. This configuration of carriers, which is variable in time, forms a powerful electric field. It, together with the recombination of ionized atomic particles, disappears after the explosion. In the process, strong electric currents are generated. They serve as an additional source of radiation. The entire described complex of effects is called an electromagnetic pulse. Despite the fact that it takes less than 1/3 of a ten-billionth of the explosive energy, it occurs within a very short period. The power that is released in this case can reach 100 GW.

Ground type processes. Peculiarities

In the process of chemical detonation, the temperature of the soil adjacent to the charge and attracted to the movement is relatively low. A nuclear explosion has its own characteristics. In particular, the ground temperature can reach tens of millions of degrees. Most of the energy generated from heating during the first moments is released into the air and goes additionally to the formation of a shock wave and thermal radiation. In a conventional explosion, these phenomena are not observed. In this regard, there are sharp differences in the impact on the soil massif and the surface. In a ground explosion of a chemical compound, up to half of the energy is transferred to the ground, and in a nuclear explosion, just a few percent. This causes the difference in the size of the funnel and the energy of seismic vibrations.

Nuclear winter

This concept characterizes the hypothetical state of the climate on the planet in the event of a large-scale war with the use of nuclear weapons. Presumably, due to the removal of a huge amount of soot and smoke into the stratosphere, the results of numerous fires, provoked by several warheads, the temperature on Earth will drop everywhere to Arctic levels. This will also be due to a significant increase in the number of solar rays reflected from the surface. The probability of global cooling was predicted a long time ago (during the existence of the Soviet Union). Later, the hypothesis was confirmed by model calculations.