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What are the damaging factors of an explosion? Characteristics and their effects on people and objects. Nuclear weapon

To the damaging factors nuclear weapons relate:

shock wave;

light radiation;

penetrating radiation;

radioactive contamination;

electromagnetic pulse.

During an explosion in the atmosphere, approximately 50% of the explosion energy is spent on the formation of a shock wave, 30-40% on light radiation, up to 5% on penetrating radiation and electromagnetic pulse, and up to 15% on radioactive contamination. Action damaging factors nuclear explosion on people and elements of objects does not occur simultaneously and varies in duration of impact, nature and scale.

Shock wave. A shock wave is an area of sharp compression of the medium, which propagates in the form of a spherical layer in all directions from the explosion site at supersonic speed. Depending on the propagation medium, a shock wave is distinguished in air, water or soil.

A shock wave in the air is formed due to the colossal energy released in the reaction zone, where the temperature is extremely high and the pressure reaches billions of atmospheres (up to 105 billion Pa). Hot vapors and gases, trying to expand, produce a sharp blow to the surrounding layers of air, compress them to high pressure and density and heat them to a high temperature. These layers of air set the subsequent layers in motion.

Thus, compression and movement of air occurs from one layer to another in all directions from the center of the explosion, forming an air shock wave. Near the center of the explosion, the speed of propagation of the shock wave is several times higher than the speed of sound in air.

As the distance from the explosion increases, the speed of wave propagation quickly decreases and the shock wave weakens. An air shock wave during a nuclear explosion of average power travels approximately 1000 meters in 1.4 seconds, 2000 meters in 4 seconds, 3000 meters in 7 seconds, 5000 meters in 12 seconds.

nuclear weapon ammunition explosion

The main parameters of the shock wave, characterizing its destructive and damaging effect: excess pressure in the front of the shock wave, the pressure of the velocity head, the duration of the wave - the duration of the compression phase and the speed of the shock wave front.

The shock wave in water during an underwater nuclear explosion is qualitatively similar to the shock wave in the air. However, at the same distances, the pressure in the shock wave front in water is much greater than in air, and the action time is shorter.

During a ground-based nuclear explosion, part of the explosion energy is spent on the formation of a compression wave in the ground. Unlike a shock wave in air, it is characterized by a less sharp increase in pressure at the wave front, as well as a slower weakening behind the front.

When a nuclear weapon explodes in the ground, the main part of the explosion energy is transferred to the surrounding mass of soil and produces a powerful shaking of the ground, reminiscent of an earthquake in its effect.

Mechanical impact of a shock wave. The nature of the destruction of the elements of an object (object) depends on the load created by the shock wave and the reaction of the object to the action of this load. A general assessment of the destruction caused by the shock wave of a nuclear explosion is usually given according to the severity of this destruction.

1) Weak destruction. Window and door fillings and light partitions are destroyed, the roof is partially destroyed, and cracks in the glass of the upper floors are possible. The basements and lower floors are completely preserved. It is safe to stay in the building and it can be used after routine repairs.
2) Moderate destruction is manifested in the destruction of roofs and built-in elements - internal partitions, windows, as well as the occurrence of cracks in the walls, the collapse of individual sections of attic floors and walls of the upper floors. The basements are preserved. After clearing and repairs, part of the premises on the lower floors can be used. Restoration of buildings is possible during major repairs.
3) Severe destruction is characterized by the destruction of load-bearing structures and floors of the upper floors, the formation of cracks in the walls and deformation of the floors of the lower floors. The use of premises becomes impossible, and repair and restoration are most often impractical.
4) Complete destruction. All the main elements of the building are destroyed, including supporting structures. The building cannot be used. In case of severe and complete destruction, basements can be preserved and partially used after the rubble is cleared.

Impact of shock waves on people and animals. The shock wave can cause traumatic injuries, concussions or death to unprotected people and animals.

Damages can be direct (as a result of exposure to excess pressure and high-speed air pressure) or indirect (as a result of impacts from debris of destroyed buildings and structures). The impact of air blast on unprotected people is characterized by mild, moderate, severe and extremely severe injuries.

1) Extremely severe contusions and injuries occur when excess pressure exceeds 100 kPa. There are gaps internal organs, bone fractures, internal bleeding, concussion, prolonged loss of consciousness. These injuries can be fatal.
2) Severe contusions and injuries are possible at excess pressures from 60 to 100 kPa. They are characterized by severe contusion of the entire body, loss of consciousness, bone fractures, bleeding from the nose and ears; Damage to internal organs and internal bleeding are possible.
3) Moderate lesions occur at excess pressure of 40-60 kPa. This may result in dislocation of limbs, contusion of the brain, damage to the hearing organs, bleeding from the nose and ears.
4) Light damage occurs at an excess pressure of 20-40 kPa. They are expressed in quickly passing disturbances in body functions (ringing in the ears, dizziness, headache). Dislocations and bruises are possible.

Guaranteed protection of people from the shock wave is provided by sheltering them in shelters. In the absence of shelters, anti-radiation shelters, underground workings, natural shelters and terrain are used.

Light radiation. The light radiation of a nuclear explosion is a combination of visible light and ultraviolet and infrared rays close to it in the spectrum. The source of light radiation is the luminous area of the explosion, consisting of substances of nuclear weapons, air and soil heated to a high temperature (in a ground explosion).

The temperature of the luminous area for some time is comparable to the temperature of the surface of the sun (maximum 8000-100000C and minimum 18000C). The size of the luminous area and its temperature change rapidly over time. The duration of light radiation depends on the power and type of explosion and can last up to tens of seconds. The damaging effect of light radiation is characterized by a light pulse. The light pulse is the ratio of the amount of light energy to the area of the illuminated surface located perpendicular to the propagation of light rays.

In a nuclear explosion high altitude X-rays emitted exclusively by highly heated explosion products are absorbed by large layers of rarefied air. Therefore, the temperature of the fireball (much larger than in an air explosion) is lower.

The amount of light energy reaching an object located at a certain distance from a ground explosion can be for short distances on the order of three-quarters, and at large distances half the impulse of an air explosion of the same power.

With ground and surface explosions, the light pulse at the same distances is less than with air explosions of the same power.

During underground or underwater explosions, almost all light radiation is absorbed.

Fires at facilities and in populated areas arise from light radiation and secondary factors caused by the impact of a shock wave. Big influence caused by the presence of flammable materials.

From the point of view of rescue operations, fires are classified into three zones: the zone of individual fires, the zone of continuous fires and the zone of burning and smoldering.

1) Zones of individual fires are areas in which fires occur in individual buildings and structures. The formation maneuver between individual fires is impossible without thermal protection equipment.
2) The zone of continuous fires is the territory in which the majority of surviving buildings are burning. It is impossible for formations to pass through this territory or remain there without means of protection from thermal radiation or carrying out special fire-fighting measures to localize or extinguish the fire.
3) The zone of burning and smoldering in the rubble is the territory in which destroyed buildings and structures are burning. It is characterized by prolonged burning in rubble (up to several days).

Impact of light radiation on people and animals. Light radiation from a nuclear explosion, when directly exposed, causes burns to exposed areas of the body, temporary blindness or retinal burns.

Burns are divided into four degrees according to the severity of damage to the body.

First degree burns cause pain, redness, and swelling of the skin. They do not pose a serious danger and are quickly cured without any consequences.

Second-degree burns cause blisters filled with a clear protein liquid; If large areas of skin are affected, a person may lose ability to work for some time and require special treatment.

Third degree burns are characterized by skin necrosis with partial damage to the germ layer.

Fourth degree burns: death of the skin of deeper layers of tissue. Third- and fourth-degree burns affecting a significant portion of the skin can be fatal.

Protection from light radiation is simpler than from other damaging factors. Light radiation travels in a straight line. Any opaque barrier can serve as protection against it. Using holes, ditches, mounds, embankments, walls between windows, various types of equipment, tree crowns and the like for shelter, you can significantly reduce or completely avoid burns from light radiation. Shelters and radiation shelters provide complete protection. Clothing also protects the skin from burns, so burns are more likely to occur on open areas bodies.

The degree of burns from light radiation to covered areas of the skin depends on the nature of the clothing, its color, density and thickness (loose clothing in light colors or clothing made from woolen fabrics is preferred).

Penetrating radiation. Penetrating radiation is gamma radiation and a flux of neutrons emitted into the environment from the zone of a nuclear explosion. Ionizing radiation is also released in the form of alpha and beta particles, which have a short free path, as a result of which their impact on people and materials is neglected. The duration of action of penetrating radiation does not exceed 10-15 seconds from the moment of explosion.

The main parameters characterizing ionizing radiation are dose and radiation dose rate, flux and particle flux density.

The ionizing ability of gamma radiation is characterized by the exposure dose of radiation. The unit of gamma radiation exposure dose is coulomb per kilogram (C/kg). In practice, the non-systemic unit roentgen (R) is used as a unit of exposure dose. X-ray is a dose (amount of energy) of gamma radiation, when absorbed in 1 cm3 of dry air (at a temperature of 0 ° C and a pressure of 760 mm Hg), 2.083 billion pairs of ions are formed, each of which has a charge equal to the charge of an electron.

The severity of radiation injury mainly depends on the absorbed dose. To measure the absorbed dose of any type of ionizing radiation, the unit gray (Gy) is established. Propagating in a medium, gamma radiation and neutrons ionize its atoms and change physical structure substances. During ionization, the atoms and molecules of living tissue cells die or lose their ability to continue living due to the disruption of chemical bonds and the breakdown of vital substances.

During air and ground nuclear explosions so close to the ground that the shock wave can disable buildings and structures, the penetrating radiation in most cases is safe for objects. But as the height of the explosion increases, it becomes increasingly important in damaging objects. In case of explosions on large height and in space the main damaging factor is the impulse of penetrating radiation.

Damage to humans and animals by penetrating radiation. Radiation sickness can occur in humans and animals when exposed to penetrating radiation. The degree of damage depends on the exposure dose of radiation, the time during which this dose was received, the area of the body irradiated, and the general condition of the body. It is also taken into account that irradiation can be single or multiple. A single exposure is considered to be the exposure received in the first four days. Irradiation received over a period of more than four days is multiple. With a single irradiation of the human body, depending on the exposure dose received, 4 degrees of radiation sickness are distinguished.

Radiation sickness of the first (mild) degree occurs with a total exposure dose of radiation of 100-200 R. The latent period can last 2-3 weeks, after which malaise, general weakness, a feeling of heaviness in the head, tightness in the chest, increased sweating appear, periodic temperature increase. The content of leukocytes in the blood decreases. First degree radiation sickness is curable.

Radiation sickness of the second (medium) degree occurs with a total exposure dose of radiation of 200-400 R. The latent period lasts about a week. Radiation sickness manifests itself in more severe illness, dysfunction nervous system, headaches, dizziness, at first there is often vomiting, possibly an increase in body temperature; the number of leukocytes in the blood, especially lymphocytes, decreases by more than half. With active treatment, recovery occurs in 1.5-2 months. Possible fatalities (up to 20%).

Radiation sickness of the third (severe) degree occurs with a total exposure dose of 400-600 R. The latent period is up to several hours. They note the severe general state, severe headaches, vomiting, sometimes loss of consciousness or sudden agitation, hemorrhages in the mucous membranes and skin, necrosis of the mucous membranes in the gum area. The number of leukocytes, and then erythrocytes and platelets, decreases sharply. Due to the weakening of the body's defenses, various infectious complications appear. Without treatment, the disease ends in death in 20-70% of cases, most often from infectious complications or bleeding.

When exposed to an exposure dose of more than 600 R., extremely severe fourth degree radiation sickness develops, which without treatment usually ends in death within two weeks.

Protection from penetrating radiation. Penetrating radiation passing through various media (materials) is attenuated. The degree of weakening depends on the properties of the materials and the thickness of the protective layer. Neutrons are weakened mainly by collisions with atomic nuclei. The energy of gamma quanta when they pass through substances is spent mainly on interaction with the electrons of atoms. Civil defense protective structures reliably protect people from penetrating radiation.

Radioactive contamination. Radioactive contamination occurs as a result of the fallout of radioactive substances from the cloud of a nuclear explosion.

The main sources of radioactivity during nuclear explosions: fission products of substances that make up nuclear fuel (200 radioactive isotopes of 36 chemical elements); induced activity resulting from the impact of the neutron flux of a nuclear explosion on some chemical elements that make up the soil (sodium, silicon and others); some part of the nuclear fuel that does not participate in the fission reaction and enters the explosion products in the form of small particles.

Radiation from radioactive substances consists of three types of rays: alpha, beta and gamma.

Gamma rays have the greatest penetrating power, beta particles have the least penetrating power, and alpha particles have the least penetrating power. Therefore, the main danger to people in case of radioactive contamination of the area is gamma and beta radiation.

Radioactive contamination has a number of features: a large area affected, the duration of the damaging effect, difficulties in detecting radioactive substances that have no color, odor and other external signs.

Zones radioactive contamination are formed in the area of a nuclear explosion and in the wake of a radioactive cloud. The greatest contamination of the area will be during ground (surface) and underground (underwater) nuclear explosions.

In a ground (underground) nuclear explosion, the fireball touches the surface of the earth. The environment becomes very hot, and much of the soil and rock is vaporized and caught in the fireball. Radioactive substances settle on molten soil particles. As a result, a powerful cloud is formed, consisting of a huge amount of radioactive and inactive fused particles, the sizes of which range from several microns to several millimeters. Within 7-10 minutes the radioactive cloud rises and reaches its maximum height, stabilizes, acquiring a characteristic mushroom shape, and under the influence of air currents moves at a certain speed and in a certain direction. Most of the radioactive fallout, which causes severe contamination of the area, falls from the cloud within 10-20 hours after a nuclear explosion.

When radioactive substances fall out of the cloud of a nuclear explosion, the surface of the earth, air, water sources, material assets, and the like are contaminated.

In airborne and high-altitude explosions, the fireball does not touch the surface of the earth. During an air explosion, almost the entire mass of radioactive products in the form of very small particles goes into the stratosphere and only a small part remains in the troposphere. Radioactive substances fall out of the troposphere within 1-2 months, and from the stratosphere - 5-7 years. During this time, radioactively contaminated particles are carried away by air currents over long distances from the explosion site and are distributed over vast areas. Therefore, they cannot create dangerous radioactive contamination of the area. The only danger can come from radioactivity induced in the soil and objects located near the epicenter of an airborne nuclear explosion. The dimensions of these zones, as a rule, will not exceed the radii of the zones of complete destruction.

The shape of the radioactive cloud's trail depends on the direction and speed of the average wind. On flat terrain with a constant wind direction, the radioactive trace has the shape of an elongated ellipse. Most high degree contamination is observed in areas of the trace located near the center of the explosion and on the axis of the trace. Larger melted particles of radioactive dust fall out here. The lowest degree of contamination is observed at the borders of contamination zones and in areas furthest from the center of a ground-based nuclear explosion.

The degree of radioactive contamination of an area is characterized by the level of radiation for a certain time after the explosion and the exposure dose of radiation (gamma radiation) received during the time from the beginning of contamination to the time of complete decay of radioactive substances.

Depending on the degree of radioactive contamination and the possible consequences of external radiation in the area of a nuclear explosion and on the trail of a radioactive cloud, zones of moderate, severe, dangerous and extremely dangerous contamination are distinguished.

Moderate infection zone (zone A). The exposure dose of radiation during the complete decay of radioactive substances ranges from 40 to 400 R. Work in open areas located in the middle of the zone or at its internal border must be stopped for several hours.

Area of heavy contamination (zone B). The exposure dose of radiation during the complete decay of radioactive substances ranges from 400 to 1200 R. In zone B, work at facilities is stopped for up to 1 day, workers and employees take refuge in protective structures of civil defense, basements or other shelters.

Dangerous contamination zone (zone B). At the outer border of the exposure zone, gamma radiation until the complete decay of radioactive substances is 1200 R., at the inner border - 4000 R. In this zone, work stops from 1 to 3-4 days, workers and employees take refuge in protective structures of the civil defense.

Extremely dangerous contamination zone (zone D). At the outer border of the zone, the exposure dose of gamma radiation until the complete decay of radioactive substances is 4000 R. In zone G, work on facilities is stopped for 4 or more days, workers and employees take refuge in shelters. After the specified period, the radiation level on the territory of the facility decreases to values that ensure safe activities of workers and employees in production premises.

The effect of nuclear explosion products on people. Like penetrating radiation in the area of a nuclear explosion, general external gamma radiation in a radioactively contaminated area causes radiation sickness in people and animals. The radiation doses that cause disease are the same as those from penetrating radiation.

When exposed to external beta particles, people most often experience skin lesions on the arms, neck, and head. Skin lesions are classified into severe (the appearance of non-healing ulcers), moderate (formation of blisters) and mild (blue and itchy skin) degrees.

Internal damage to people by radioactive substances can occur when they enter the body, mainly through food. With air and water, radioactive substances will apparently enter the body in such quantities that will not cause acute radiation injury with loss of ability to work in people.

The absorbed radioactive products of a nuclear explosion are distributed extremely unevenly in the body. They are especially concentrated in the thyroid gland and liver. In this regard, these organs are exposed to very high doses of radiation, leading either to tissue destruction or to the development of tumors ( thyroid), or to serious impairment of function.

Depending on the tasks solved by nuclear weapons, on the type and location of the objects at which nuclear explosions are planned, as well as on the nature of the upcoming hostilities, nuclear explosions can be carried out in the air, near the surface of the earth (water) and underground (water). In accordance with this, the following types of nuclear explosions are distinguished: airborne, high-altitude (in rarefied layers of the atmosphere), ground-based (above-water), underground (underwater).

A nuclear explosion can instantly destroy or disable unprotected people, openly standing equipment, structures and various material assets. The main damaging factors of a nuclear explosion (NFE) are:

· shock wave;

· light radiation;

· penetrating radiation;

· radioactive contamination of the area;

· electromagnetic pulse (EMP).

During a nuclear explosion in the atmosphere, the distribution of released energy between PFYVs is approximately the following: about 50% for the shock wave, 35% for light radiation, 10% for radioactive contamination and 5% for penetrating radiation and EMR.

Shock wave. The shock wave in most cases is the main damaging factor of a nuclear explosion. By its nature, it is similar to the shock wave of a completely ordinary explosion, but it acts more long time and has much greater destructive power. The shock wave of a nuclear explosion can injure people at a considerable distance from the center of the explosion, destroy structures and damage military equipment.

A shock wave is an area of strong air compression that propagates at high speed in all directions from the center of the explosion. Its propagation speed depends on the air pressure at the front of the shock wave; near the center of the explosion it is several times higher than the speed of sound, but with increasing distance from the explosion site it drops sharply. In the first 2 s the shock wave travels about 1000 m, in 5 s – 2000 m, in 8 s – about 3000 m.

The damaging effects of a shock wave on people and the destructive effect on military equipment, engineering structures and materiel are, first of all, determined by excess pressure and the speed of air movement in its front. Unprotected people can, in addition, be affected by shards of glass flying at great speed and fragments of destroyed buildings, falling trees, as well as scattered parts of military equipment, clods of earth, stones and other objects set in motion by the high-speed pressure of the shock wave. The greatest indirect damage will be observed in populated areas and forests; in these cases, population losses may be greater than from the direct effect of the shock wave. Damages caused by a shock wave are divided into light, medium, severe and extremely severe.

Mild lesions occur at excess pressure of 20-40 kPa (0.2-0.4 kgf/cm2) and are characterized by temporary damage to the hearing organs, general mild contusion, bruises and dislocations of the limbs. Medium lesions occur at excess pressure of 40-60 kPa (0.4-0.6 kgf/cm2). This may result in dislocation of the limbs, contusion of the brain, damage to the hearing organs, and bleeding from the nose and ears. Severe injuries are possible with excess shock wave pressure of 60-100 kPa (0.6-1.0 kgf/cm2) and are characterized by severe contusion of the whole body; In this case, damage to the brain and abdominal organs, severe bleeding from the nose and ears, severe fractures and dislocations of the limbs may occur. Extremely severe injuries can lead to death if excess pressure exceeds 100 kPa (1.0 kgf/cm2).

The degree of damage from a shock wave depends, first of all, on the power and type of nuclear explosion. In an air explosion with a power of 20 kt, light injuries to people are possible at distances of up to 2.5 km, medium - up to 2 km, severe - up to 1.5 km, extremely severe - up to 1.0 km from the epicenter of the explosion. As the caliber of a nuclear weapon increases, the radius of shock wave damage increases in proportion to the cube root of the explosion power.

Guaranteed protection of people from the shock wave is provided by sheltering them in shelters. In the absence of shelters, natural shelters and terrain are used.

During an underground explosion, a shock wave occurs in the ground, and during an underwater explosion, it occurs in water. The shock wave, propagating in the ground, causes damage to underground structures, sewers, and water pipes; when it spreads in water, damage to the underwater parts of ships located even at a considerable distance from the explosion site is observed.

In relation to civil and industrial buildings, the degrees of destruction are characterized by weak, medium, severe and complete destruction.

Weak destruction is accompanied by the destruction of window and door fillings and light partitions, the roof is partially destroyed, and cracks are possible in the walls of the upper floors. The basements and lower floors are completely preserved.

Moderate destruction manifests itself in the destruction of roofs, internal partitions, windows, collapse of attic floors, and cracks in walls. Restoration of buildings is possible during major repairs.

Severe destruction is characterized by the destruction of load-bearing structures and ceilings of the upper floors, and the appearance of cracks in the walls. The use of buildings becomes impossible. Repair and restoration of buildings becomes impractical.

In case of complete destruction, all the main elements of the building collapse, including supporting structures. It is impossible to use such buildings, and so that they do not pose a danger, they are completely collapsed.

Light radiation. The light emitted from a nuclear explosion is a stream of radiant energy, including ultraviolet, visible and infrared radiation. The source of light radiation is a luminous area consisting of hot explosion products and hot air. The brightness of light radiation in the first second is several times greater than the brightness of the Sun. Maximum temperature The luminous region is in the range of 8000-10000 C 0.

The damaging effect of light radiation is characterized by a light pulse. The light pulse is the ratio of the amount of light energy to the area of the illuminated surface located perpendicular to the propagation of light rays. The unit of light impulse is joule per square meter (J/m2) or calorie per square centimeter (cal/cm2).

The absorbed energy of light radiation turns into heat, which leads to heating of the surface layer of the material. The heat can be so intense that it can char or ignite combustible material and crack or melt non-combustible material, which can lead to huge fires. In this case, the effect of light radiation from a nuclear explosion is equivalent to the massive use incendiary weapons.

The human skin also absorbs the energy of light radiation, due to which it can heat up to a high temperature and receive burns. First of all, burns occur on open areas of the body facing the direction of the explosion. If you look in the direction of the explosion with unprotected eyes, eye damage may occur, leading to complete loss of vision.

Burns caused by light radiation are no different from burns caused by fire or boiling water. They are stronger the shorter the distance to the explosion and the greater the power of the ammunition. In an air explosion, the damaging effect of light radiation is greater than in a ground explosion of the same power. Depending on the perceived magnitude of the light pulse, burns are divided into three degrees.

First-degree burns occur with a light pulse of 2-4 cal/cm 2 and manifest themselves in superficial skin lesions: redness, swelling, pain. In case of second degree burns, with a light pulse of 4-10 cal/cm2, blisters appear on the skin. In case of third degree burns with a light pulse of 10-15 cal/cm2, skin necrosis and the formation of ulcers are observed.

With an air explosion of ammunition with a power of 20 kt and an atmospheric transparency of about 25 km, first-degree burns will be observed within a radius of 4.2 km from the center of the explosion; with the explosion of a charge with a power of 1 Mt, this distance will increase to 22.4 km. Second degree burns appear at distances of 2.9 and 14.4 km and third degree burns at distances of 2.4 and 12.8 km, respectively, for 20 kt and 1 Mt ammunition

Protection from light radiation can be various items, creating a shadow, but top scores achieved by using shelters and shelters.

Penetrating radiation. Penetrating radiation is a stream of gamma quanta and neutrons emitted from the zone of a nuclear explosion. Gamma quanta and neutrons spread in all directions from the center of the explosion.

As the distance from the explosion increases, the number of gamma quanta and neutrons passing through a unit surface decreases. During underground and underwater nuclear explosions, the effect of penetrating radiation extends over distances much shorter than during ground and air explosions, which is explained by the absorption of the flux of neutrons and gamma quanta by earth and water.

The zones affected by penetrating radiation during explosions of medium- and high-power nuclear weapons are somewhat smaller than the zones affected by shock waves and light radiation.

For ammunition with a small TNT equivalent (1000 tons or less), on the contrary, the damage zones of penetrating radiation exceed the zones of damage by shock waves and light radiation.

The damaging effect of penetrating radiation is determined by the ability of gamma rays and neutrons to ionize the atoms of the medium in which they propagate. Passing through living tissue, gamma rays and neutrons ionize atoms and molecules that make up the cells, which lead to disruption of the vital functions of individual organs and systems. Under the influence of ionization, biological processes of cell death and decomposition occur in the body. As a result, affected people develop a specific disease called radiation sickness (see below for more details). teaching aid“Radiation safety: nature and sources of ionizing radiation”).

To assess the ionization of atoms in the environment, and, consequently, the damaging effect of penetrating radiation on a living organism, the concept of radiation dose (or radiation dose) was introduced, the unit of measurement of which is the x-ray (R). The 1P radiation dose corresponds to the formation of approximately 2 billion ion pairs in one cubic centimeter of air.

They serve as protection against penetrating radiation various materials, weakening the flux of gamma and neutron radiation. The degree of attenuation of penetrating radiation depends on the properties of the materials and the thickness of the protective layer. The attenuation of gamma and neutron radiation intensity is characterized by a half-attenuation layer, which depends on the density of the materials. A half-attenuation layer is a layer of material through which the intensity of gamma rays or neutrons is halved.

Radioactive contamination. Radioactive contamination of people, military equipment, terrain and various objects during a nuclear explosion is caused by fission fragments of the charge substance (Pu-239, U-235, U-238) and the unreacted part of the charge falling out of the explosion cloud, as well as induced radioactivity. Over time, the activity of fission fragments decreases rapidly, especially in the first hours after the explosion. For example, the total activity of fission fragments in the explosion of a nuclear weapon with a yield of 20 kt after one day will be several thousand times less than one minute after the explosion.

When a nuclear weapon explodes, part of the charge substance does not undergo fission, but falls out in its usual form; its decay is accompanied by the formation of alpha particles. Induced radioactivity is caused by radioactive isotopes (radionuclides) formed in the soil as a result of irradiation with neutrons emitted at the moment of explosion by the nuclei of atoms of chemical elements that make up the soil. The resulting isotopes, as a rule, are beta-active, and the decay of many of them is accompanied by gamma radiation. The half-lives of most of the resulting radioactive isotopes are relatively short - from one minute to an hour. In this regard, induced activity can pose a danger only in the first hours after the explosion and only in the area close to the epicenter.

The bulk of long-lived isotopes are concentrated in the radioactive cloud that forms after the explosion. The height of the cloud rise for a 10 kt munition is 6 km, for a 10 Mt munition it is 25 km. As the cloud moves, first the largest particles fall out of it, and then smaller and smaller ones, forming along the path of movement a zone of radioactive contamination, the so-called cloud trail. The size of the trace depends mainly on the power of the nuclear weapon, as well as on wind speed, and can reach several hundred kilometers in length and several tens of kilometers in width.

The degree of radioactive contamination of an area is characterized by the level of radiation for a certain time after the explosion. The radiation level is the exposure dose rate (R/h) at a height of 0.7-1 m above the contaminated surface.

The emerging zones of radioactive contamination according to the degree of danger are usually divided into the following four zones.

Zone G is an extremely dangerous area for infection. Its area is 2-3% of the area of the explosion cloud trace. The radiation level is 800 R/h.

Zone B - dangerous contamination. It occupies approximately 8-10% of the explosion cloud footprint; radiation level 240 R/h.

Zone B is highly contaminated, accounting for approximately 10% of the area of the radioactive trace, the radiation level is 80 R/h.

Zone A - moderate contamination with an area of 70-80% of the area of the entire explosion trace. The radiation level at the outer border of the zone 1 hour after the explosion is 8 R/h.

Injuries as a result of internal radiation appear due to the entry of radioactive substances into the body through the respiratory system and gastrointestinal tract. In this case, radioactive radiation comes into direct contact with internal organs and can cause severe radiation sickness; the nature of the disease will depend on the amount of radioactive substances entering the body.

Radioactive substances do not have any harmful effects on weapons, military equipment and engineering structures.

Electromagnetic pulse. Nuclear explosions in the atmosphere and in higher layers lead to the emergence of powerful electromagnetic fields. Due to their short-term existence, these fields are usually called an electromagnetic pulse (EMP).

The damaging effect of EMR is caused by the occurrence of voltages and currents in conductors of various lengths located in the air, equipment, on the ground or on other objects. The effect of EMR manifests itself, first of all, in relation to radio-electronic equipment, where, under the influence of EMR, electric currents and voltages are induced, which can cause breakdown of electrical insulation, damage to transformers, burnout of spark gaps, damage to semiconductor devices and other elements of radio engineering devices. Communication, signaling and control lines are most susceptible to EMR. Strong electromagnetic fields can damage electrical circuits and interfere with the operation of unshielded electrical equipment.

A high-altitude explosion can interfere with communications by very large areas. Protection against EMI is achieved by shielding power supply lines and equipment.

The source of nuclear damage. The source of nuclear damage is the territory in which, under the influence of the damaging factors of a nuclear explosion, destruction of buildings and structures, fires, radioactive contamination of the area and damage to the population occur. The simultaneous impact of a shock wave, light radiation and penetrating radiation largely determines the combined nature of the damaging effect of a nuclear weapon explosion on people, military equipment and buildings. In case of combined damage to people, injuries and contusions from the impact of a shock wave can be combined with burns from light radiation with simultaneous fire from light radiation. Electronic equipment and devices, in addition, may lose their functionality as a result of exposure to an electromagnetic pulse (EMP).

The more powerful the nuclear explosion, the larger the source size. The nature of the destruction in the outbreak also depends on the strength of the structures of buildings and structures, their number of storeys and building density.

The outer boundary of the source of nuclear damage is taken to be a conventional line on the ground drawn at a distance from the epicenter of the explosion where the excess pressure of the shock wave is 10 kPa.

2. Damaging factors of a nuclear explosion

A nuclear explosion can instantly destroy or disable unprotected people, openly standing equipment, structures and various material assets. The main damaging factors of a nuclear explosion (NFE) are:

shock wave;

light radiation;

penetrating radiation;

radioactive contamination of the area;

electromagnetic pulse (EMP).

Shock wave

The shock wave in most cases is the main damaging factor of a nuclear explosion. By its nature, it is similar to the shock wave of a completely ordinary explosion, but it lasts longer and has much greater destructive power. The shock wave of a nuclear explosion can injure people, destroy structures and damage military equipment at a considerable distance from the center of the explosion.

A shock wave is an area of strong air compression that propagates at high speed in all directions from the center of the explosion. Its propagation speed depends on the air pressure at the front of the shock wave; near the center of the explosion it is several times higher than the speed of sound, but with increasing distance from the explosion site it drops sharply. In the first 2 s, the shock wave travels about 1000 m, in 5 s - 2000 m, in 8 s - about 3000 m.

The damaging effects of a shock wave on people and the destructive effect on military equipment, engineering structures and materiel are primarily determined by excess pressure and the speed of air movement in its front. Unprotected people can, in addition, be affected by shards of glass flying at great speed and fragments of destroyed buildings, falling trees, as well as scattered parts of military equipment, clods of earth, stones and other objects set in motion by the high-speed pressure of the shock wave. The greatest indirect damage will be observed in populated areas and forests; in these cases, population losses may be greater than from the direct effect of the shock wave. Damages caused by a shock wave are divided into light, medium, severe and extremely severe.

The degree of damage from a shock wave depends primarily on the power and type of nuclear explosion. In an air explosion with a power of 20 kT, light injuries to people are possible at distances of up to 2.5 km, medium - up to 2 km, severe - up to 1.5 km, extremely severe - up to 1.0 km from the epicenter of the explosion. As the caliber of a nuclear weapon increases, the radius of shock wave damage increases in proportion to the cube root of the explosion power.

Guaranteed protection of people from the shock wave is provided by sheltering them in shelters. In the absence of shelters, natural shelters and terrain are used.

In relation to civil and industrial buildings, the degrees of destruction are characterized by weak, medium, severe and complete destruction.

Light radiation

The light emitted from a nuclear explosion is a stream of radiant energy, including ultraviolet, visible and infrared radiation. The source of light radiation is a luminous area consisting of hot explosion products and hot air. The brightness of light radiation in the first second is several times greater than the brightness of the Sun. The maximum temperature of the luminous area is in the range of 8000-10000 oC.

First-degree burns occur with a light pulse of 2-4 cal/cm2 and manifest themselves in superficial skin lesions: redness, swelling, pain. In case of second degree burns, with a light pulse of 4-10 cal/cm2, blisters appear on the skin. In case of third degree burns with a light pulse of 10-15 cal/cm2, skin necrosis and the formation of ulcers are observed.

With an air explosion of ammunition with a power of 20 kT and an atmospheric transparency of about 25 km, first-degree burns will be observed within a radius of 4.2 km from the center of the explosion; with the explosion of a charge with a power of 1 MgT, this distance will increase to 22.4 km. Second degree burns occur at distances of 2.9 and 14.4 km and third degree burns at distances of 2.4 and 12.8 km, respectively, for 20 kT and 1 MgT ammunition.

Protection from light radiation can be provided by various objects that create shadow, but the best results are achieved by using shelters and shelters.

Penetrating radiation

Penetrating radiation is a stream of gamma quanta and neutrons emitted from the zone of a nuclear explosion. Gamma quanta and neutrons spread in all directions from the center of the explosion.

The zones affected by penetrating radiation during explosions of medium- and high-power nuclear weapons are somewhat smaller than the zones affected by shock waves and light radiation.

For ammunition with a small TNT equivalent (1000 tons or less), on the contrary, the damage zones of penetrating radiation exceed the zones of damage by shock waves and light radiation.

To assess the ionization of atoms in the environment, and therefore the damaging effect of penetrating radiation on a living organism, the concept of radiation dose (or radiation dose) was introduced, the unit of measurement of which is the x-ray (R). The 1P radiation dose corresponds to the formation of approximately 2 billion ion pairs in one cubic centimeter of air.

Depending on the radiation dose, there are four degrees of radiation sickness. The first (mild) occurs when a person receives a dose of 100 to 200 R. It is characterized by general weakness, mild nausea, short-term dizziness, and increased sweating; Personnel who receive such a dose usually do not fail. The second (medium) degree of radiation sickness develops when receiving a dose of 200-300 R; in this case, signs of damage - headache, fever, gastrointestinal upset - appear more sharply and quickly, and personnel in most cases fail. The third (severe) degree of radiation sickness occurs at a dose above 300-500 R; it is characterized by severe headaches, nausea, severe general weakness, dizziness and other ailments; severe form often leads to death. A radiation dose of more than 500 R causes radiation sickness of the fourth degree and is usually considered lethal for humans.

Protection against penetrating radiation is provided by various materials that weaken the flow of gamma and neutron radiation. The degree of attenuation of penetrating radiation depends on the properties of the materials and the thickness of the protective layer. The attenuation of gamma and neutron radiation intensity is characterized by a half-attenuation layer, which depends on the density of the materials.

A half-attenuation layer is a layer of material through which the intensity of gamma rays or neutrons is halved.

Radioactive contamination

Radioactive contamination of people, military equipment, terrain and various objects during a nuclear explosion is caused by fission fragments of the charge substance (Pu-239, U-235, U-238) and the unreacted part of the charge falling out of the explosion cloud, as well as induced radioactivity. Over time, the activity of fission fragments decreases rapidly, especially in the first hours after the explosion. For example, the total activity of fission fragments during the explosion of a nuclear weapon with a power of 20 kT after one day will be several thousand times less than one minute after the explosion.

The bulk of long-lived isotopes are concentrated in the radioactive cloud that forms after the explosion. The height of the cloud rise for a 10 kT munition is 6 km, for a 10 MgT munition it is 25 km. As the cloud moves, first the largest particles fall out of it, and then smaller and smaller ones, forming along the path of movement a zone of radioactive contamination, the so-called cloud trail. The size of the trace depends mainly on the power of the nuclear weapon, as well as on wind speed, and can reach several hundred kilometers in length and several tens of kilometers in width.

The emerging zones of radioactive contamination according to the degree of danger are usually divided into the following four zones.

Zone G is an extremely dangerous area for infection. Its area is 2-3% of the area of the explosion cloud trace. The radiation level is 800 R/h.

Zone B - dangerous contamination. It occupies approximately 8-10% of the explosion cloud footprint; radiation level 240 R/h.

Zone B is highly contaminated, accounting for approximately 10% of the area of the radioactive trace, the radiation level is 80 R/h.

Zone A - moderate contamination with an area of 70-80% of the area of the entire explosion trace. The radiation level at the outer border of the zone 1 hour after the explosion is 8 R/h.

Injuries resulting from internal radiation occur due to the entry of radioactive substances into the body through the respiratory system and gastrointestinal tract. In this case, radioactive radiation comes into direct contact with internal organs and can cause severe radiation sickness; the nature of the disease will depend on the amount of radioactive substances entering the body.

Radioactive substances do not have any harmful effects on weapons, military equipment and engineering structures.

Electromagnetic pulse

Nuclear explosions in the atmosphere and in higher layers lead to the emergence of powerful electromagnetic fields. Due to their short-term existence, these fields are usually called an electromagnetic pulse (EMP).

A high-altitude explosion can interfere with communications over very large areas. Protection against EMI is achieved by shielding power supply lines and equipment.

3 Nuclear source

The source of nuclear damage is the territory in which, under the influence of the damaging factors of a nuclear explosion, destruction of buildings and structures, fires, radioactive contamination of the area and damage to the population occur. The simultaneous impact of a shock wave, light radiation and penetrating radiation largely determines the combined nature of the damaging effect of a nuclear weapon explosion on people, military equipment and structures. In case of combined damage to people, injuries and contusions from the impact of a shock wave can be combined with burns from light radiation with simultaneous fire from light radiation. Electronic equipment and devices, in addition, may lose their functionality as a result of exposure to an electromagnetic pulse (EMP).

Light gates, etc.). Penetrating radiation from a nuclear explosion. Penetrating radiation from a nuclear explosion is a stream of gamma rays and neutrons emitted into the environment from the nuclear explosion zone. Only free neutrons have a damaging effect on the human body, i.e. those that are not part of the nuclei of atoms. During a nuclear explosion, they are formed in a chain reaction...

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 isotope nuclei. Thermonuclear reactions release 5 times more energy than fission reactions (with the same mass of nuclei).

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

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

Ammunition with a power of up to 100 kt is constructed using fission reactions, and from 100 to 1000 kt (1 Mt) using fusion reactions. Combined ammunition can have a yield of more than 1 Mt. Based on their power, nuclear weapons are divided into ultra-small (up to 1 kg), small (1-10 kt), medium (10-100 kt) and super-large (more than 1 Mt).

Depending on the purpose of using nuclear weapons, nuclear explosions can be high-altitude (above 10 km), airborne (no higher than 10 km), ground-based (surface), underground (underwater).

Damaging factors of a nuclear explosion

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

Shock wave

Shock wave (SW)- an area 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 them to a high temperature (several tens of thousands of degrees). This layer of compressed air represents a shock wave. The front boundary of the compressed air layer is called the shock wave front. The shock front is followed by a region of rarefaction, where the pressure is below atmospheric. Near the center of the explosion, the speed of propagation of shock waves is several times higher than the speed of sound. As the distance from the explosion increases, the speed of wave propagation quickly decreases. At large distances, its speed approaches the speed of sound in air.

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

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

The impact of hydrocarbons on people can be direct and indirect. With direct impact, 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, rupture blood vessels. With indirect exposure, people are affected by flying debris from buildings and structures, stones, trees, broken glass and other items. Indirect impact reaches 80% of all lesions.

With an excess pressure of 20-40 kPa (0.2-0.4 kgf/cm2), unprotected people can suffer minor injuries (minor bruises and contusions). Exposure to hydrocarbons with excess pressure of 40-60 kPa leads to moderate damage: loss of consciousness, damage to the hearing organs, severe dislocations of the limbs, damage to internal organs. Extremely severe injuries, often fatal, are observed at excess pressure above 100 kPa.

The degree of shock wave damage to various objects depends on the power and type of explosion, 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 effects of hydrocarbons, the following should be used: trenches, cracks and trenches, reducing this effect by 1.5-2 times; dugouts - 2-3 times; shelters - 3-5 times; basements of houses (buildings); terrain (forest, ravines, hollows, etc.).

Light radiation

Light radiation is a stream of radiant energy that includes ultraviolet, visible and infrared rays.

Its source is a luminous area formed by hot explosion products and hot air. Light radiation spreads almost instantly and lasts, depending on the power of the nuclear explosion, up to 20 s. However, its strength is such that, despite its short duration, it can cause burns to the skin (skin), damage (permanent or temporary) to the organs of vision of people and fire of flammable 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 the light pulse.

Light impulse is the amount of energy in calories incident on a unit surface area perpendicular to the direction of radiation during the entire glow time.

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

To protect the population from light radiation, it is necessary to use protective structures, basements of houses and buildings, protective properties terrain. Any barrier that can create a shadow protects against the direct action of light radiation and prevents burns.

Penetrating radiation

Penetrating radiation- notes of gamma rays and neutrons emitted from the zone of a nuclear explosion. Its duration is 10-15 s, range is 2-3 km from the center of the explosion.

In conventional nuclear explosions, neutrons make up approximately 30%, and in the explosion of neutron weapons - 70-80% of 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 some materials and can cause induced activity in metals and technology.

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

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

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

As protection against penetrating radiation, protective structures are used that weaken its effects from 200 to 5000 times. A pound layer of 1.5 m protects almost completely from penetrating radiation.

Radioactive contamination (contamination)

Radioactive contamination of air, terrain, water areas 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 approximately 1700 °C, the glow of the luminous region of a nuclear explosion stops and it turns into a dark cloud, towards which a dust column rises (that’s why the cloud has a mushroom shape). This cloud moves in the direction of the wind, and radioactive substances fall out of it.

Sources of radioactive substances in the cloud are fission products of nuclear fuel (uranium, plutonium), unreacted part of nuclear fuel and radioactive isotopes formed as a result of the action of neutrons on the ground (induced activity). These radioactive substances, when located on contaminated objects, decay, emitting ionizing radiation, which is actually a damaging factor.

Parameters radioactive contamination are the radiation dose (based on the impact on people) and the radiation dose rate - the radiation level (based on 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.

In an area exposed to radioactive contamination during a nuclear explosion, two areas are formed: the explosion area and the cloud trail.

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

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

Zone B- an area of heavy 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 contamination. It is characterized by radiation doses at the boundaries of 1200 rad and 4000 rad.

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

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

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 from 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 atoms of the medium under the influence of gamma radiation. Its duration of action is several milliseconds.

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

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

Most effective protection from electromagnetic pulses is shielding of power supply and control lines, as well as radio and electrical equipment.

The situation that arises when nuclear weapons are used in areas of destruction.

A hotbed of nuclear destruction is a territory within which, as a result of the use of nuclear weapons, there have been mass casualties and deaths of people, farm animals and plants, destruction and damage to buildings and structures, utility, energy and technological networks and lines, transport communications and other objects.

Nuclear explosion zones

To determine the nature of possible destruction, the volume and conditions for carrying out rescue and other urgent work, the source of nuclear damage is conventionally divided into four zones: complete, severe, medium and weak destruction.

Zone of complete destruction has at the border an excess pressure at the shock wave front of 50 kPa 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, energy and technological networks and lines, as well as parts of civil defense shelters, the formation of continuous rubble in populated areas. The forest is completely destroyed.

Zone of severe destruction with excess pressure 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, energy and technological networks and lines, formation of local and continuous blockages in settlements and forests, preservation of shelters and most anti-radiation shelters of the basement type.

Medium Damage Zone with excess pressure from 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 debris, continuous fires, preservation of utility and energy networks, shelters and most anti-radiation shelters.

Light Damage Zone with excess pressure from 10 to 20 kPa is characterized by weak and moderate destruction of buildings and structures.

The source of damage in terms of the number of dead and injured may be comparable to or greater than the source of damage during an earthquake. Thus, 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 was up to 140,000 people.

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

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

In the context of military operations with the use of nuclear weapons, vast territories may be in zones of radioactive contamination, and the irradiation of people may become widespread. To avoid overexposure of facility personnel and the public under such conditions and to increase the stability of the functioning of national economic facilities in conditions of radioactive contamination in wartime, permissible radiation doses are established. They are:

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 irradiation (during the year) 300 rad.

Caused by the use of nuclear weapons, the most complex. To eliminate them, disproportionately greater forces and means are required than when eliminating peacetime emergencies.

Nuclear weapons - type of weapon mass destruction explosive action based on the use of intranuclear energy. Nuclear weapons, one of the most destructive means of warfare, are among the main types of weapons of mass destruction. It includes various nuclear weapons (warheads of missiles and torpedoes, aircraft and depth charges, artillery shells and mines equipped with nuclear chargers), means of controlling them and means of delivering them to the target (missiles, aviation, artillery). The destructive effect of nuclear weapons is based on the energy released during nuclear explosions.

Nuclear explosions are usually divided into air, ground (surface) and underground (underwater). The point at which the explosion occurred is called the center, and its projection on the surface of the earth (water) is called the epicenter of the nuclear explosion.

By air called an explosion, the luminous cloud of which does not touch the surface of the earth (water). Depending on the power of the ammunition, it can be located at an altitude from several hundred meters to several kilometers. There is practically no radioactive contamination of the area during an airborne nuclear explosion (Fig. 17).

Ground (surface) a nuclear explosion is carried out on the surface of the earth (water) or at such a height when the luminous area of the explosion touches the surface of the earth (water) and has the shape of a hemisphere. Its damage radius is approximately 20% less than that of the air.

A characteristic feature of a ground (surface) nuclear explosion- severe radioactive contamination of the area in the area of the explosion and along the trace of the movement of the radioactive cloud (Fig. 18).

Underground (underwater) called an explosion produced underground (underwater). The main damaging factor of an underground explosion is a compression wave propagating in the soil or water (Fig. 19, 20).

A nuclear explosion is accompanied by a bright flash and a sharp, deafening sound reminiscent of thunderclaps. In an air explosion, following the flash, a fireball is formed (in the case of a ground explosion, a hemisphere), which quickly increases, rises, cools and turns into a swirling cloud, shaped like a mushroom.

The damaging factors of a nuclear explosion are shock wave, light radiation, penetrating radiation, radioactive contamination and electromagnetic pulse.

Shock wave - one of the main damaging factors of a nuclear explosion, since most of the destruction and damage to structures, buildings, as well as injuries to people are caused by its impact.

Depending on the nature of the destruction at the source of nuclear damage four zones are distinguished: complete, strong, medium and weak destruction.

Basic a method of protection against a shock wave is the use of shelters (shelters).

Light radiation is a stream of radiant energy, including ultraviolet, visible and infrared rays. Its source is a luminous area formed by hot explosion products and hot air.

Light radiation spreads almost instantly and lasts, depending on the power of the nuclear explosion, up to 20 s. It can cause skin burns, damage (permanent or temporary) to people's vision, and fire of flammable materials and objects.

Various objects that create shadows can serve as protection from light radiation. Light radiation does not penetrate through opaque materials, so any barrier that can create a shadow protects against the direct action of light radiation and protects against burns. The best results are achieved when using shelters and shelters that simultaneously protect from other damaging factors of a nuclear explosion.

Under the influence of light radiation and a shock wave, fires, combustion and smoldering in the rubble occur in the source of nuclear damage. The set of fires that occur in the source of nuclear damage is usually called mass fires. Fires at the source of nuclear damage continue long time, so they can cause a large number of destruction and cause more damage than the shock wave.

Light radiation is significantly weakened in dusty (smoky) air, fog, rain, and snowfall.

Penetrating radiation - This is ionizing radiation in the form of a stream of gamma rays and neutrons. Its sources are nuclear reactions flowing in the ammunition at the moment of explosion, and radioactive decay fission fragments (products) in the explosion cloud.

The duration of action of penetrating radiation on ground objects is 15-25 s. It is determined by the time the explosion cloud rises to such a height (2-3 km) at which gamma-neutron radiation, absorbed by the air, practically does not reach the earth's surface.

Passing through living tissue, gamma radiation and neutrons ionize molecules that make up living cells, disrupt metabolism and vital functions of organs, which leads to radiation sickness.

As a result of radiation passing through environmental materials, its intensity decreases. For example, the intensity of gamma rays is reduced by 2 times in steel with a thickness of 2.8 cm, concrete - 10 cm, soil - 14 cm, wood - 30 cm (Fig. 21).

Nuclear pollution. Its main sources are nuclear fission products and radioactive isotopes, formed as a result of the impact of neutrons on the materials from which nuclear weapons are made, and on some elements that make up the soil in the area of the explosion.

In a ground-based nuclear explosion, the glowing area touches the ground. Masses of evaporating soil are drawn inside it and rise upward. As they cool, the vapors of fission products and soil condense. A radioactive cloud is formed. It rises to a height of many kilometers, and then moves at a speed of 25-100 km/h air masses in the direction the wind blows. Radioactive particles falling from a cloud to the ground form a zone of radioactive contamination (trace), the length of which can reach several hundred kilometers. In this case, the area, buildings, structures, crops, reservoirs, etc., as well as the air, become infected. Contamination of terrain and objects on the trail of a radioactive cloud occurs unevenly. There are zones of moderate (A), severe (B), hazardous (C) and extremely dangerous (D) pollution.

Moderate pollution zone (zone A)- the first part of the trace from the outside. Its area makes up 70-80% of the entire footprint. External border zones of heavy pollution (zone B, about 10% of the track area) is combined with the inner border of zone A. The outer border zones of hazardous pollution (zone B, 8-10% of the track area) coincides with the inner border of zone B. Extremely hazardous pollution zone (zone D) occupies approximately 2-3% of the track area and is located in zone B (Fig. 22).

Radioactive substances pose the greatest danger in the first hours after deposition, since during this period their activity is greatest.

Electromagnetic pulse is a short-term electromagnetic field that occurs during the explosion of a nuclear weapon as a result of the interaction of gamma rays and neutrons emitted with the atoms of the environment. The consequence of its impact may be the failure of individual elements of radio-electronic and electrical equipment. People can only be harmed if they come into contact with wire lines at the time of the explosion.

Questions and tasks

1. Define and characterize nuclear weapons.

2. Name the types of nuclear explosions and briefly describe each of them.

3. What is called the epicenter of a nuclear explosion?

4. List the damaging factors of a nuclear explosion and describe them.

5. Describe the zones of radioactive contamination. In which zone do radioactive substances pose the least danger?

Task 25

Exposure to what damaging factor of a nuclear explosion can cause skin burns, damage to human eyes and fires? Choose the correct answer from the given options:

a) exposure to light radiation;
b) exposure to penetrating radiation;
c) exposure to an electromagnetic pulse.

Task 26

What determines the time of action of penetrating radiation on ground objects? Select the correct answer from the given options:

a) type of nuclear explosion;
b) nuclear charge power;
c) action electromagnetic field arising from the explosion of a nuclear weapon;
d) the time the explosion cloud rises to a height at which gamma-neutron radiation practically does not reach the earth’s surface;
e) the time of propagation of the luminous region that appears during a nuclear explosion, formed by the hot products of the explosion and hot air.

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