The damaging factor is the formation of a specific cloud in the atmosphere. Nuclear explosion
Damaging factors of nuclear weapons
Nuclear weapons called a weapon lethal effect which is based on the use of intranuclear energy released during a nuclear explosion. These weapons include various nuclear munitions (warheads of missiles and torpedoes, aircraft and depth charges, artillery shells and mines) equipped with nuclear chargers, means for controlling them and delivering them to the target.
The main part of a nuclear weapon is a nuclear charge containing a nuclear explosive (NE) - uranium-235 or plutonium-239. A nuclear chain reaction can only develop if there is critical mass fissile substance. Before the explosion, nuclear explosives in one ammunition must be divided into separate parts, each of which must be less than critical in mass.
The power of a nuclear explosion is usually characterized by its TNT equivalent.
The center of a nuclear explosion is the point at which a nuclear reaction occurs. According to the position of the center relative to the ground or water, nuclear explosions are distinguished: space, high-altitude, air, ground, underground, surface, underwater.
Aerial nuclear explosion is an explosion produced in the air at such a height that the fireball does not touch the surface of the earth. It is accompanied by a short-term blinding flash, visible even on a sunny day at a distance of hundreds of kilometers. An airborne nuclear explosion is used to destroy buildings, structures and kill people. It causes damage by shock wave, light radiation and penetrating radiation. There is practically no radioactive contamination of the area during an air explosion, since the radioactive products of the explosion rise along with the fireball to a very high altitude, without mixing with soil particles.
Ground nuclear explosion An explosion on the surface of the earth or at such a height from it is called when the luminous area touches the ground and, as a rule, has the shape of a truncated sphere. Increasing in size and cooling, the fireball lifts off the ground, darkens and turns into a swirling cloud, which, carrying a column of dust with it, after a few minutes acquires a characteristic mushroom shape. During a ground-based nuclear explosion, it rises into the air a large number of soil. Ground explosion is used to destroy durable ground structures.
Surface nuclear explosion called an explosion on the surface of the water or at a height at which the luminous area touches the surface of the water. Used to destroy surface watercraft. The damaging factors in a surface explosion are the air wave and waves formed on the surface of the water. Action light radiation and penetrating radiation is significantly attenuated as a result of the shielding effect large mass water vapor.
The explosion cloud involves a large amount of water and steam formed under the influence of light radiation. After the cloud cools, the steam condenses and drops of water fall out in the form of radioactive rain, severely contaminating the water and area in the area of the explosion and in the direction of the cloud's movement.
Underground nuclear explosion called an explosion produced below the surface of the earth. During an underground explosion, a huge amount of soil is thrown out to a height of several kilometers, and at the site of the explosion a deep crater is formed, the dimensions of which are larger than in a ground explosion. Underground explosions are used to destroy buried structures. The main damaging factor of an underground nuclear explosion is a compression wave propagating in the ground. An underground explosion causes severe contamination of the area in the area of the explosion and in the wake of the cloud.
Underwater nuclear explosion called an explosion produced under water at a depth that varies widely. During an underwater nuclear explosion, a hollow column of water rises with big cloud at the top. The diameter of the water column reaches several hundred meters, and the height - several kilometers and depends on the power and depth of the explosion. The main damaging factor of an underwater explosion is a shock wave in water, the speed of which is equal to the speed of sound in water, i.e. approximately 1500 m/sec. The shock wave in the water destroys the underwater parts of ships and various hydraulic structures. Light radiation and penetrating radiation are absorbed by the water column and water vapor. An underwater explosion causes severe radioactive contamination of water. When an explosion occurs near the shore, contaminated water is thrown out by a base wave onto the coast, flooding it and causing severe contamination of objects located on the shore.
One of the types of nuclear weapons is neutron munition. This is a small-sized thermonuclear charge with a power of no more than 10 thousand tons, in which the main share of energy is released due to the fusion reactions of deuterium and tritium, and the amount of energy obtained as a result of the fission of heavy nuclei in the detonator is minimal, but sufficient to start the fusion reaction. The neutron component of the penetrating radiation of such a low-power nuclear explosion will have the main damaging effect on people.
When a nuclear weapon explodes, a colossal amount of energy is released in millionths of a second. The temperature rises to several million degrees, and the pressure reaches billions of atmospheres. High temperature and pressure cause light radiation and a powerful shock wave. Along with this, the explosion of a nuclear weapon is accompanied by the emission of penetrating radiation, consisting of a stream of neutrons and gamma quanta. The explosion cloud contains a huge amount of radioactive products - fragments of nuclear fission explosive, which fall along the path of the cloud, resulting in radioactive contamination of the area, air and objects. Uneven movement electric charges in the air, arising under the influence of ionizing radiation, leads to the formation electromagnetic pulse.
The main damaging factors of a nuclear explosion are:
1) shock wave – 50% of the explosion energy;
2) light radiation – 30–35% of the explosion energy;
3) penetrating radiation – 8–10% of the explosion energy;
4) radioactive contamination – 3–5% of the explosion energy;
5) electromagnetic pulse - 0.5–1% of the explosion energy.
Shock wave of a nuclear explosion– one of the main damaging factors. Depending on the medium in which the shock wave arises and propagates - in air, water or soil, it is called, respectively, an air wave, a shock wave in water and a seismic explosion wave (in soil). An air shock wave is an area of sharp compression of air that spreads in all directions from the center of the explosion at supersonic speed.
The shock wave causes open and closed injuries of varying severity in humans. Great danger for humans there is also an indirect effect shock wave. By destroying buildings, shelters and shelters, it can cause serious injury. The main way to protect people and equipment from shock wave damage is to isolate them from the effects of excess pressure and high-velocity pressure. Shelters and refuges are used for this purpose. various types and folds of the terrain.
Light radiation from a nuclear explosion represents electromagnetic radiation, including the visible ultraviolet and infrared regions of the spectrum. The energy of light radiation is absorbed by the surfaces of illuminated bodies, which heat up. The heating temperature may be such that the surface of the object will char, melt or ignite. Light radiation can cause burns to exposed areas of the human body, and in dark time days – temporary blindness. Source of light radiation is the luminous area of the explosion, consisting of vapors of structural materials of ammunition and air heated to a high temperature, and in case of ground explosions - evaporated soil. Dimensions of the luminous area and the time of its glow depend on the power, and the shape - on the type of explosion.
Impact level light radiation on various buildings, structures, and equipment depends on the properties of their structural materials. Melting, charring, and ignition of materials in one place can lead to the spread of fire and massive fires.
Light protection simpler than against other damaging factors, since any opaque barrier, any object that creates a shadow, can serve as protection.
Penetrating radiation is a stream of gamma radiation and neutrons emitted from the zone of a nuclear explosion. Gamma radiation and neutron radiation are different in their physical properties. What they have in common is that they can spread in the air in all directions over a distance of up to 2.5–3 km. Passing through biological tissue, gamma and neutron radiation ionize the atoms and molecules that make up living cells, as a result of which normal metabolism is disrupted and the nature of the vital activity of cells, individual organs and systems of the body changes, which leads to the emergence of a specific disease - radiation sickness.
The source of penetrating radiation is the nuclear fission and fusion reactions occurring in ammunition at the moment of explosion, as well as the radioactive decay of fission fragments.
The damaging effect of penetrating radiation on people is caused by irradiation, which has harmful biological effect on living cells of the body. Passing through living tissue, penetrating radiation ionizes the atoms and molecules that make up the cells. This leads to disruption of the activity of cells, individual organs and body systems. The damaging effect of penetrating radiation depends on the magnitude of the radiation dose and the time during which this dose is received. A dose received in a short period of time causes more severe damage than a dose of equal magnitude, but received over a period of time. longer time. This is explained by the fact that the body is able to restore some of the cells damaged by radiation over time. The speed of recovery is determined by the half-life of recovery, equal to 28-30 days for people. The dose of radioactive radiation received during the first four days from the moment of irradiation is called a single dose, and after longer period time - multiple. In wartime, a dose of radiation that does not lead to a decrease in performance and combat effectiveness personnel formations accepted: single entry (within the first four days) 50 RUR, multiple entry within the first 10-30 days – 100 RUR, within three months – 200 RUR, within a year – 300 RUR.
Damaging factors of a nuclear explosion
Depending on the type of charge and the conditions of the explosion, the energy of the explosion is distributed differently. For example, during the explosion of a conventional nuclear charge without an increased yield of neutron radiation or radioactive contamination there may be the following ratio of the shares of energy output at different altitudes:
Energy shares of the influencing factors of a nuclear explosion | |||||||||
Height / Depth | X-ray radiation | Light radiation | The warmth of the fireball and cloud | Shock wave in the air | Deformation and ejection of soil | Compression wave in the ground | Heat of a cavity in the earth | Penetrating radiation | Radioactive substances |
---|---|---|---|---|---|---|---|---|---|
100 km | 64 % | 24 % | 6 % | 6 % | |||||
70 km | 49 % | 38 % | 1 % | 6 % | 6 % | ||||
45 km | 1 % | 73 % | 13 % | 1 % | 6 % | 6 % | |||
20 km | 40 % | 17 % | 31 % | 6 % | 6 % | ||||
5 km | 38 % | 16 % | 34 % | 6 % | 6 % | ||||
0 m | 34 % | 19 % | 34 % | 1 % | less than 1% | ? | 5 % | 6 % | |
Camouflage explosion depth | 30 % | 30 % | 34 % | 6 % |
During a ground-based nuclear explosion, about 50% of the energy goes to the formation of a shock wave and a crater in the ground, 30-40% to light radiation, up to 5% to penetrating radiation and electromagnetic radiation, and up to 15% to radioactive contamination of the area.
In an air explosion neutron ammunition the energy shares are distributed in a unique way: shock wave up to 10%, light radiation 5 - 8% and approximately 85% of the energy goes into penetrating radiation (neutron and gamma radiation)
The shock wave and light radiation are similar to the damaging factors of traditional explosives, but the light radiation in the event of a nuclear explosion is much more powerful.
The shock wave destroys buildings and equipment, injures people and has a knockback effect with a rapid pressure drop and high-speed air pressure. Subsequent vacuum (drop in air pressure) and reverse stroke air masses towards the developing nuclear mushroom can also cause some damage.
Light radiation affects only unshielded objects, that is, objects not covered by anything from an explosion, and can cause ignition of flammable materials and fires, as well as burns and damage to the vision of humans and animals.
Penetrating radiation has an ionizing and destructive effect on human tissue molecules and causes radiation sickness. Especially great importance has in the explosion of a neutron ammunition. Basements of multi-story stone and reinforced concrete buildings, underground shelters with a depth of 2 meters (a cellar, for example, or any shelter of class 3-4 and higher) can be protected from penetrating radiation; armored vehicles have some protection.
Radioactive contamination - during an air explosion of relatively “pure” thermonuclear charges (fission-fusion), this damaging factor is minimized. And vice versa, in the event of an explosion of “dirty” variants of thermonuclear charges, arranged according to the principle of fission-fusion-fission, a ground, buried explosion, in which neutron activation of substances contained in the ground occurs, and even more so the explosion of a so-called “dirty bomb” may have a decisive meaning.
An electromagnetic pulse disables electrical and electronic equipment and disrupts radio communications.
Shock wave
The most terrible manifestation of an explosion is not a mushroom, but a fleeting flash and the shock wave formed by it
Formation of a bow shock wave (Mach effect) during an explosion of 20 kt
Destruction in Hiroshima as a result of the atomic bombing
Much of the destruction caused by a nuclear explosion is caused by the shock wave. A shock wave is a shock wave in a medium that moves at supersonic speed (more than 350 m/s for the atmosphere). In an atmospheric explosion, a shock wave is a small zone in which there is an almost instantaneous increase in temperature, pressure and air density. Directly behind the shock wave front there is a decrease in air pressure and density, from a slight decrease far from the center of the explosion to almost a vacuum inside the fire sphere. The consequence of this decrease is the reverse flow of air and strong wind along the surface at speeds of up to 100 km/h or more towards the epicenter. The shock wave destroys buildings, structures and affects unprotected people, and close to the epicenter of a ground or very low air explosion it generates powerful seismic vibrations that can destroy or damage underground structures and communications, and injure people in them.
Most buildings, except specially fortified ones, are seriously damaged or destroyed under the influence of excess pressure of 2160-3600 kg/m² (0.22-0.36 atm).
The energy is distributed over the entire distance traveled, because of this the force of the shock wave decreases in proportion to the cube of the distance from the epicenter.
Shelters provide protection against shock waves for humans. On open area the effect of the shock wave is reduced by various depressions, obstacles, and folds in the terrain.
Optical radiation
Victim of the nuclear bombing of Hiroshima
Light radiation is a stream of radiant energy, including ultraviolet, visible and infrared regions of the spectrum. The source of light radiation is the luminous area of the explosion - heated to high temperatures and evaporated parts of the ammunition, surrounding soil and air. In an air explosion, the luminous area is a ball; in a ground explosion, it is a hemisphere.
Maximum temperature the surface of the luminous region is usually 5700-7700 °C. When the temperature drops to 1700 °C, the glow stops. The light pulse lasts from fractions of a second to several tens of seconds, depending on the power and conditions of the explosion. Approximately, the duration of the glow in seconds is equal to the third root of the explosion power in kilotons. In this case, the radiation intensity can exceed 1000 W/cm² (for comparison, the maximum intensity of sunlight is 0.14 W/cm²).
The result of light radiation can be the ignition and combustion of objects, melting, charring, and high temperature stresses in materials.
When a person is exposed to light radiation, damage to the eyes and burns to open areas of the body occur, and damage to areas of the body protected by clothing may also occur.
An arbitrary opaque barrier can serve as protection from the effects of light radiation.
In the presence of fog, haze, heavy dust and/or smoke, the impact of light radiation is also reduced.
Penetrating radiation
Electromagnetic pulse
In a nuclear explosion resulting strong currents In air ionized by radiation and light, a strong alternating electromagnetic field, called an electromagnetic pulse (EMP), appears. Although it has no effect on humans, exposure to EMR damages electronic equipment, electrical appliances and power lines. In addition, the large number of ions generated after the explosion interferes with the propagation of radio waves and the operation of radar stations. This effect can be used to blind a missile warning system.
The strength of the EMP varies depending on the height of the explosion: in the range below 4 km it is relatively weak, stronger at an explosion of 4-30 km, and especially strong at a detonation altitude of more than 30 km (see, for example, the experiment on high-altitude detonation of a nuclear charge Starfish Prime) .
The occurrence of EMR occurs as follows:
- Penetrating radiation emanating from the center of the explosion passes through extended conductive objects.
- Gamma quanta are scattered by free electrons, which leads to the appearance of a rapidly changing current pulse in conductors.
- The field caused by the current pulse is emitted into the surrounding space and propagates at the speed of light, distorting and fading over time.
Under the influence of EMR, a voltage is induced in all unshielded long conductors, and the longer the conductor, the higher the voltage. This leads to insulation breakdowns and failure of electrical appliances associated with cable networks, for example, transformer substations, etc.
EMR is of great importance during a high-altitude explosion of up to 100 km or more. When an explosion occurs in the ground layer of the atmosphere, it does not cause decisive damage to low-sensitive electrical equipment; its range of action is covered by other damaging factors. But on the other hand, it can disrupt the operation and disable sensitive electrical equipment and radio equipment at considerable distances - up to several tens of kilometers from the epicenter of a powerful explosion, where other factors no longer have a destructive effect. It can disable unprotected equipment in durable structures designed to withstand heavy loads from a nuclear explosion (for example, silos). It has no harmful effect on people.
Radioactive contamination
Crater from the explosion of a 104-kiloton charge. Soil emissions also serve as a source of contamination
Radioactive contamination is the result of a significant amount of radioactive substances falling out of a cloud lifted into the air. The three main sources of radioactive substances in the explosion zone are fission products of nuclear fuel, the unreacted part of the nuclear charge, and radioactive isotopes formed in the soil and other materials under the influence of neutrons (induced radioactivity).
As the explosion products settle on the surface of the earth in the direction of movement of the cloud, they create a radioactive area called a radioactive trace. The density of contamination in the area of the explosion and along the trace of the movement of the radioactive cloud decreases with distance from the center of the explosion. The shape of the trace can be very diverse, depending on the surrounding conditions.
The radioactive products of an explosion emit three types of radiation: alpha, beta and gamma. The time of their impact on the environment is very long.
Due to the natural decay process, radioactivity decreases, especially sharply in the first hours after the explosion.
Impact on humans and animals radiation contamination can be caused by external and internal radiation. Severe cases may be accompanied by radiation sickness and death.
Installing a cobalt shell on the warhead of a nuclear charge causes contamination of the area with the dangerous isotope 60 Co (a hypothetical dirty bomb).
Epidemiological and environmental situation
A nuclear explosion in a populated area, like other disasters associated with big amount casualties, destruction of hazardous industries and fires will lead to difficult conditions in the area of its action, which will be a secondary damaging factor. People who did not even receive significant injuries directly from the explosion, with high probability may die from infectious diseases And chemical poisoning. There is a high probability of getting burned in fires or simply getting hurt when trying to get out of the rubble.
Psychological impact
People who find themselves in the area of the explosion, in addition to physical damage, experience a powerful psychological depressing effect from the striking and frightening view of the unfolding picture of a nuclear explosion, the catastrophic nature of the destruction and fires, the many corpses and mutilated living around, the death of relatives and friends, the awareness of the harm caused to their body. The result of such an impact will be a poor psychological situation among survivors of the disaster, and subsequently persistent negative memories that affect the person’s entire subsequent life. In Japan there is a separate word for people who have become victims nuclear bombings- “Hibakusha”.
Government intelligence services in many countries assume
Damaging factors of nuclear weapons and their brief characteristics.
The characteristics of the damaging effect of a nuclear explosion and the main damaging factor are determined not only by the type of nuclear weapon, but also by the power of the explosion, the type of explosion and the nature of the affected object (target). All these factors are taken into account when assessing the effectiveness of a nuclear strike and developing the content of measures to protect troops and facilities from nuclear weapons.
When a nuclear weapon explodes in millionths of a second, a colossal amount of energy is released and therefore in the zone of nuclear reactions the temperature rises to several million degrees, and the maximum pressure reaches billions of atmospheres. High temperatures and pressures cause a powerful shock wave.
Along with the shock wave and light radiation, the explosion of a nuclear weapon is accompanied by the emission of penetrating radiation, consisting of a stream of neutrons and g-quanta. The explosion cloud contains a huge amount of radioactive products - fission fragments. Along the path of movement of this cloud, radioactive products fall out of it, resulting in radioactive contamination of the area, objects and air.
The uneven movement of electrical charges in the air, arising under the influence of ionized radiation, leads to the formation of an electromagnetic pulse (EMP).
Damaging factors of a nuclear explosion:
1) shock wave;
2) light radiation;
3) penetrating radiation;
4) radioactive radiation;
5) electromagnetic pulse (EMP).
1) Shock wave A nuclear explosion is one of the main damaging factors. Depending on the medium in which the shock wave arises and propagates - air, water or soil - it is called, respectively, an air wave, a shock wave (in water) and a seismic blast wave (in soil).
A shock wave is an area of sharp compression of air, spreading in all directions from the center of the explosion at supersonic speed. Possessing a large supply of energy, the shock wave of a nuclear explosion is capable of defeating people, destroying various structures, weapons, military equipment and other objects at significant distances from the explosion site.
The main parameters of a shock wave are the excess pressure at the wave front, the duration of action and its velocity pressure.
2) Under light radiation A nuclear explosion refers to electromagnetic radiation in the optical range in the visible, ultraviolet and infrared regions of the spectrum.
The source of light radiation is the luminous area of the explosion, consisting of substances of nuclear weapons heated to a high temperature, air and soil particles raised by the explosion from earth's surface. The shape of the luminous area during an air explosion is spherical; during ground explosions it is close to a hemisphere; at low air explosions the spherical shape is deformed by the shock wave reflected from the ground. The size of the luminous area is proportional to the power of the explosion.
Light radiation from a nuclear explosion is divided only in a few seconds. The duration of the glow depends on the power of the nuclear explosion. The greater the power of the explosion, the longer the glow. The temperature of the luminous region is from 2000 to 3000 0 C. For comparison, we point out that the temperature of the surface layers of the Sun is 6000 0 C.
The main parameter characterizing light radiation at various distances from the center of a nuclear explosion is the light pulse. A light pulse is the amount of light energy incident on a unit surface area perpendicular to the direction of radiation during the entire glow time of the source. Light impulse is measured in calories per square centimeter (cal/cm2).
Light radiation primarily affects exposed areas of the body - hands, face, neck, and eyes, causing burns.
There are four degrees of burns:
First degree burn – is a superficial lesion of the skin, externally manifested in its redness;
Second degree burn – characterized by the formation of blisters;
Third degree burn – causes death of the deep layers of the skin;
Fourth degree burn - the skin and subcutaneous tissue, and sometimes deeper tissues, are charred.
3) Penetrating radiation is a flux of g-radiation and neutrons emitted into the environment from the zone and cloud of a nuclear explosion.
g-radiation and neutron radiation are different in their physical properties; they can propagate in the air in all directions over a distance of 2.5 to 3 km.
The duration of action of penetrating radiation is only a few seconds, but nevertheless it is capable of causing severe damage to personnel, especially if they are located openly.
g-rays and neutrons, propagating in any medium, ionize its atoms. As a result of the ionization of atoms that make up living tissues, various vital processes in the body are disrupted, which leads to radiation sickness.
In addition, penetrating radiation can cause darkening of glass, exposure of light-sensitive photographic materials and damage radio-electronic equipment, especially those containing semiconductor elements.
The damaging effect of penetrating radiation on personnel and on the state of their combat effectiveness depends on the dose of radiation and the time elapsed after the explosion.
The damaging effect of penetrating radiation is characterized by the radiation dose.
A distinction is made between exposure dose and absorbed dose.
Exposure dose was previously measured in non-systemic units - roentgens (R). One roentgen is a dose of x-ray or g-radiation that creates 2.1 10 9 pairs of ions in one cubic centimeter of air. IN new system SI units exposure dose is measured in Coulombs per kilogram (1 P = 2.58 10 -4 C/kg).
The absorbed dose is measured in radians (1 Rad = 0.01 J/kg = 100 erg/g absorbed energy in the tissue). The SI unit of absorbed dose is Gray (1 Gy=1 J/kg=100 Rad). The absorbed dose more accurately determines the impact of ionizing radiation on biological tissues of the body, which have different atomic composition and density.
Depending on the radiation dose, there are four degrees of radiation sickness:
1) Radiation sickness of the first degree (mild) occurs with a total radiation dose of 150-250 Rad. The latent period lasts 2-3 weeks, after which malaise, general weakness, nausea, dizziness, periodic increase temperature. The content of white blood cells in the blood decreases. First degree radiation sickness is curable.
2) Radiation sickness of the second degree (medium) occurs with a total radiation dose of 250-400 Rad. The latent period lasts about a week. Signs of the disease are more pronounced. With active treatment, recovery occurs in 1.5-2 months.
3) Radiation sickness of the third degree (severe), occurs with a radiation dose of 400-700 Rad. The latent period is several hours. The disease is intense and difficult. If the outcome is favorable, recovery may occur in 6-8 months.
4) Radiation sickness of the fourth degree (extremely severe), occurs with a radiation dose of over 700 Rad, which is the most dangerous. At doses exceeding 500 Rad, personnel lose their combat effectiveness within a few minutes.
4) Radioactive contamination of the area , ground layer of the atmosphere, airspace, water and other objects arises as a result of the fallout of radioactive substances from the cloud of a nuclear explosion.
The main source of radioactive contamination during nuclear explosions are radioactive products nuclear radiation– fission fragments of uranium and plutonium nuclei. The decay of fragments is accompanied by the emission of gamma rays and beta particles.
The significance of radioactive contamination as a damaging factor is determined by the fact that high levels radiation can be observed not only in the area adjacent to the explosion site, but also at a distance of tens and even hundreds of kilometers from it.
The most severe contamination of the area occurs during ground-based nuclear explosions, when the areas of contamination with dangerous levels of radiation are many times greater than the size of the zones affected by the shock wave, light radiation and penetrating radiation.
In an area exposed to radioactive contamination during a nuclear explosion, two areas are formed: the explosion area and the cloud trail. In turn, in the area of the explosion, windward and leeward sides are distinguished.
According to the degree of danger, the contaminated area following the explosion cloud is usually divided into four zones:
1. zone A – moderate infection. Radiation doses until complete decay of radioactive substances at the outer boundary of the zone D ¥ =40 Rad, at the inner boundary D ¥ =400 Rad. Its area makes up 70-80% of the entire footprint.
2. zone B – severe infection. Radiation doses at the boundaries D ¥ =400 Rad and D ¥ =1200 Rad. This zone accounts for approximately 10% of the area of the radioactive trace.
3. zone B – dangerous infection. Radiation doses at its outer boundary during the period of complete decay of radioactive substances D ¥ =1200 Rad, and at the inner boundary D ¥ =4000 Rad. This zone occupies approximately 8-10% of the explosion cloud footprint.
4. Zone G – extremely dangerous infection. Radiation doses at its outer boundary during the period of complete decay of radioactive substances D ¥ =4000 Rad, and in the middle of the zone D ¥ =7000 Rad.
The radiation levels at the outer boundaries of these zones 1 hour after the explosion are respectively 8; 80; 240 and 800 Rad/h, and after 10 hours – 0.5; 5; 15 and 50 Rad/h. Over time, radiation levels in the area decrease by approximately 10 times over time intervals divisible by 7. For example, 7 hours after the explosion the dose rate decreases by 10 times, and after 49 hours by 100 times.
5) Electromagnetic pulse (AMY). Nuclear explosions in the atmosphere and in higher layers lead to the emergence of powerful electromagnetic fields with wavelengths from 1 to 1000 m or more. These fields, due to their short-term existence, 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, on the ground, on weapons and military equipment and other objects.
During a ground or low air explosion, g-quanta emitted from the zone of nuclear explosions knock out fast electrons from air atoms, which fly in the direction of movement of g-quanta at a speed close to the speed of light, and positive ions (remnants of atoms) remain in place . As a result of this separation of electric charges in space, elementary and resulting electric and magnetic fields of EMR are formed.
In a ground and low air explosion, the damaging effects of EMP are observed at a distance of about several kilometers from the center of the explosion.
During a high-altitude nuclear explosion (height more than 10 km), EMR fields can arise in the explosion zone and at altitudes of 20-40 km from the surface.
The damaging effect of EMR manifests itself primarily in relation to radio-electronic and electrical equipment located in weapons, military equipment and other objects.
If nuclear explosions occur near long-distance power supply and communication lines, then the voltages induced in them can spread along the wires for many kilometers and cause damage to equipment and injury to personnel located at a safe distance in relation to other damaging factors of a nuclear explosion.
EMP also poses a danger in the presence of durable structures (sheltered command posts, missile launch complexes), which are designed to withstand the effects of shock waves from a ground-based nuclear explosion carried out at a distance of several hundred meters. Strong electromagnetic fields can damage electrical circuits and disrupt the operation of unshielded electronic and electrical equipment, requiring time to recover.
A high-altitude explosion can interfere with communications by very large areas.
Defense against nuclear weapons is one of the the most important species combat support. It is organized and carried out with the aim of preventing the defeat of troops by nuclear weapons, maintaining their combat effectiveness and ensuring the successful completion of the assigned task. This is achieved:
Conducting reconnaissance of nuclear attack weapons;
Using personal protective equipment, protective properties equipment, terrain, engineering structures;
Skillful actions in contaminated areas;
Carrying out control of radioactive exposure, sanitary and hygienic events;
Timely elimination of the consequences of the enemy’s use of weapons mass destruction;
The main methods of protection against nuclear weapons:
Reconnaissance and destruction launchers With nuclear warheads;
Radiation reconnaissance nuclear explosion areas;
Warning troops about the danger of an enemy nuclear attack;
Dispersal and camouflage of troops;
Engineering equipment for troop deployment areas;
Elimination of the consequences of the use of nuclear weapons.
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 resources. 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 more destructive force. 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, 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 civilians and industrial buildings degrees of destruction are characterized by weak, medium, strong 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. The maximum temperature of 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 of 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 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 Mt 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.
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 in the body there arise biological processes cell death and decomposition. 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, general activity Fission fragments from 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 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).
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 over 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 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).
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.
Nuclear weapons is a weapon whose destructive effect is based on the use of intranuclear energy released during a nuclear explosion.
Nuclear weapons are based on the use of intranuclear energy released during chain reactions of fission of heavy nuclei of the isotopes uranium-235, plutonium-239 or during thermonuclear reactions of fusion of light hydrogen isotope nuclei (deuterium and tritium) into heavier ones.
These weapons include various nuclear munitions (warheads of missiles and torpedoes, aircraft and depth charges, artillery shells and mines) equipped with nuclear chargers, means for controlling them and delivering them to the target.
The main part of a nuclear weapon is a nuclear charge containing a nuclear explosive (NE) - uranium-235 or plutonium-239.
A nuclear chain reaction can only develop if there is a critical mass of fissile material. Before the explosion, nuclear explosives in one ammunition must be divided into separate parts, each of which must be less than critical in mass. To carry out an explosion it is necessary to connect them into a single whole, i.e. create a supercritical mass and initiate the start of the reaction from a special neutron source.
The power of a nuclear explosion is usually characterized by its TNT equivalent.
The use of fusion reactions in thermonuclear and combined ammunition makes it possible to create weapons with virtually unlimited power. Nuclear fusion of deuterium and tritium can be carried out at temperatures of tens and hundreds of millions of degrees.
In reality, in the ammunition this temperature is reached during the nuclear fission reaction, creating conditions for the development of a thermonuclear fusion reaction.
An assessment of the energy effect of the thermonuclear fusion reaction shows that during fusion 1 kg. Helium energy is released from a mixture of deuterium and tritium in 5p. more than when dividing 1 kg. uranium-235.
One of the types of nuclear weapons is neutron ammunition. This is a small-sized thermonuclear charge with a power of no more than 10 thousand tons, in which the main share of energy is released due to the fusion reactions of deuterium and tritium, and the amount of energy obtained as a result of the fission of heavy nuclei in the detonator is minimal, but sufficient to start the fusion reaction.
The neutron component of the penetrating radiation of such a low-power nuclear explosion will have the main damaging effect on people.
For a neutron munition at the same distance from the epicenter of the explosion, the dose of penetrating radiation is approximately 5-10 rubles greater than for a fission charge of the same power.
Nuclear ammunition of all types, depending on their power, are divided into the following types:
1. ultra-small (less than 1 thousand tons);
2. small (1-10 thousand tons);
3. medium (10-100 thousand tons);
4. large (100 thousand - 1 million tons).
Depending on the tasks solved with the use of nuclear weapons, Nuclear explosions are divided into the following types:
1. air;
2. high-rise;
3. ground (surface);
4. underground (underwater).
Damaging factors of a nuclear explosion
When a nuclear weapon explodes, a colossal amount of energy is released in millionths of a second. The temperature rises to several million degrees, and the pressure reaches billions of atmospheres.
High temperature and pressure cause light radiation and a powerful shock wave. Along with this, the explosion of a nuclear weapon is accompanied by the emission of penetrating radiation, consisting of a stream of neutrons and gamma rays. The explosion cloud contains a huge amount of radioactive fission products of a nuclear explosive, which fall along the path of the cloud, resulting in radioactive contamination of the area, air and objects.
The uneven movement of electric charges in the air, which occurs under the influence of ionizing radiation, leads to the formation of an electromagnetic pulse.
The main damaging factors of a nuclear explosion are:
1. shock wave - 50% of the explosion energy;
2. light radiation - 30-35% of the explosion energy;
3. penetrating radiation - 8-10% of explosion energy;
4. radioactive contamination - 3-5% of explosion energy;
5. electromagnetic pulse - 0.5-1% of explosion energy.
Nuclear weapon- This is one of the main types of weapons of mass destruction. It is capable of a short time disable a large number of people and animals, destroy buildings and structures over vast areas. Mass application nuclear weapons are fraught catastrophic consequences for all humanity, therefore Russian Federation persistently and steadily fights for its prohibition.
The population must firmly know and skillfully apply methods of protection against weapons of mass destruction, otherwise huge losses are inevitable. Everyone knows horrible consequences atomic bombings in August 1945 of the Japanese cities of Hiroshima and Nagasaki - tens of thousands of dead, hundreds of thousands of injured. If the population of these cities knew the means and methods of protecting themselves from nuclear weapons, were notified of the danger and took refuge in a shelter, the number of victims could be significantly less.
The destructive effect of nuclear weapons is based on the energy released during explosive nuclear reactions. TO nuclear weapons include nuclear weapons. The basis of a nuclear weapon is a nuclear charge, the power of the damaging explosion of which is usually expressed in TNT equivalent, i.e., the amount of conventional explosive, the explosion of which releases the same amount of energy as it would be released during the explosion of a given nuclear weapon. It is measured in tens, hundreds, thousands (kilos) and millions (mega) tons.
The means of delivering nuclear weapons to targets are missiles (the main means of delivering nuclear strikes), aviation and artillery. In addition, nuclear land mines can be used.
Nuclear explosions are carried out in the air at different heights, near the surface of the earth (water) and underground (water). In accordance with this, they are usually divided into high-altitude, air, ground (surface) and underground (underwater). The point at which the explosion occurred is called the center, and its projection onto the surface of the earth (water) is called the epicenter of the nuclear explosion.
The damaging factors of a nuclear explosion are shock wave, light radiation, penetrating radiation, radioactive contamination and electromagnetic pulse.
Shock wave- the main damaging factor of a nuclear explosion, since most of the destruction and damage to structures, buildings, as well as injuries to people are, as a rule, caused by its impact. The source of its occurrence is the strong pressure formed in the center of the explosion and reaching billions of atmospheres in the first moments. The area of strong compression of the surrounding layers of air formed during the explosion, expanding, transfers pressure to neighboring layers of air, compressing and heating them, and they, in turn, affect the following layers. As a result, a high-pressure zone spreads in the air at supersonic speed in all directions from the center of the explosion. The front boundary of the compressed layer of air is called shock wave front.
The degree of damage to various objects by a shock wave 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 it.
The damaging effect of a shock wave is characterized by the magnitude of excess pressure. Overpressure is the difference between the maximum pressure at the shock wave front and normal atmospheric pressure ahead of the wave front. It is measured in newtons per square meter (N/meter squared). This unit of pressure is called Pascal (Pa). 1 N/meter square = 1 Pa (1 kPa * 0.01 kgf/cm square).
With excess pressure of 20 - 40 kPa, unprotected people can suffer minor injuries (minor bruises and contusions). Exposure to a shock wave with an excess pressure of 40 - 60 kPa leads to lesions moderate severity: loss of consciousness, hearing damage, severe dislocations of limbs, bleeding from the nose and ears. Severe injuries occur when excess pressure exceeds 60 kPa and are characterized by severe contusions of the entire body, fractures of the limbs, and damage to internal organs. Extremely severe lesions, often fatal, are observed at an excess pressure of 100 kPa.
The speed of movement and the distance over which the shock wave propagates depend on the power of the nuclear explosion; As the distance from the explosion increases, the speed quickly decreases. Thus, when an ammunition with a power of 20 kt explodes, the shock wave travels 1 km in 2 s, 2 km in 5 s, 3 km in 8 s. During this time, a person after the flash can take cover and thereby avoid being hit by the shock wave.
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. 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.
Light radiation does not penetrate through opaque materials, so any barrier that can create a shadow protects against direct action light radiation and eliminates burns. Light radiation is significantly weakened in dusty (smoky) air, fog, rain, and snowfall.
Penetrating radiation is a stream of gamma rays and neutrons. It lasts 10-15 s. Passing through living tissue, gamma radiation ionizes the molecules that make up the cells. Under the influence of ionization, biological processes arise in the body, leading to disruption of the vital functions of individual organs and the development of radiation sickness.
As a result of radiation passing through materials environment the radiation intensity decreases. The attenuating effect is usually characterized by a layer of half attenuation, i.e. such a thickness of material, passing through which the radiation is halved. For example, the intensity of gamma rays is reduced by half: steel 2.8 cm thick, concrete 10 cm, soil 14 cm, wood 30 cm.
Open and especially closed cracks reduce the impact of penetrating radiation, and shelters and anti-radiation shelters almost completely protect against it.
Main sources radioactive contamination are fission products of a nuclear charge 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, vapors from fission products and soil condense on solid particles. A radioactive cloud is formed. It rises to a height of many kilometers, and then moves with the wind at a speed of 25-100 km/h. Radioactive particles falling from the 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.
Radioactive substances pose the greatest danger in the first hours after deposition, since their activity is highest during this period.
Electromagnetic pulse- these are electric and magnetic fields arising as a result of the impact of gamma radiation from a nuclear explosion on the atoms of the environment and the formation of a flow of electrons and positive ions in this environment. It can cause damage to radio-electronic equipment and disruption of radio and radio-electronic equipment.
The most reliable means of protection against all damaging factors of a nuclear explosion are protective structures. In the field you should take cover behind strong local objects, reverse slopes of heights, and in folds of the terrain.
When operating in contaminated zones, to protect the respiratory organs, eyes and open areas of the body from radioactive substances, respiratory protective equipment (gas masks, respirators, anti-dust fabric masks and cotton-gauze bandages), as well as skin protection products, are used.
The basis neutron ammunition constitute thermonuclear charges that use nuclear fission and fusion reactions. The explosion of such ammunition has a damaging effect, primarily on people, due to the powerful flow of penetrating radiation.
When a neutron munition explodes, the area affected by penetrating radiation exceeds the area affected by the shock wave by several times. In this zone, equipment and structures can remain unharmed, but people will receive fatal injuries.
The source of nuclear destruction is the territory directly exposed to the damaging factors of a nuclear explosion. It is characterized by massive destruction of buildings and structures, rubble, accidents in utility networks, fires, radioactive contamination and significant losses among the population.
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 such a distance from the epicenter (center) of the explosion where the excess pressure of the shock wave is equal to 10 kPa.
The source of nuclear damage is conventionally divided into zones - areas with approximately the same nature of destruction.
Zone of complete destruction- this is an area exposed to a shock wave with excess pressure (at the outer boundary) of over 50 kPa. All buildings and structures in the zone, as well as anti-radiation shelters and part of the shelters, are completely destroyed, continuous rubble is formed, and the utility and energy network is damaged.
Zone of strengths destruction- with excess pressure in the shock wave front from 50 to 30 kPa. In this zone, ground buildings and structures will be severely damaged, local rubble will form, and continuous and massive fires will occur. Most shelters will remain intact; some shelters will have their entrances and exits blocked. People in them can be injured only due to a violation of the sealing of the shelters, their flooding or gas contamination.
Medium Damage Zone excess pressure in the shock wave front from 30 to 20 kPa. In it, buildings and structures will suffer moderate damage. Shelters and basement-type shelters will remain. Light radiation will cause continuous fires.
Zone of weak damage with excess pressure in the shock wave front from 20 to 10 kPa. Buildings will suffer minor damage. Individual fires will arise from light radiation.
Radioactive contamination zone- this is an area that has been contaminated with radioactive substances as a result of their fallout after ground (underground) and low air nuclear explosions.
The damaging effect of radioactive substances is determined mainly by gamma radiation. The harmful effects of ionizing radiation are assessed by the radiation dose (radiation dose; D), i.e. the energy of these rays absorbed per unit volume of the irradiated substance. This energy is measured in existing dosimetric instruments in roentgens (R). X-ray - This is a dose of gamma radiation that creates 1 cubic cm of dry air (at a temperature of 0 degrees C and a pressure of 760 mm Hg) 2.083 billion ion pairs.
Typically, the radiation dose is determined over a period of time called exposure time (the time people spend in the contaminated area).
To assess the intensity of gamma radiation emitted by radioactive substances in a contaminated area, the concept of “radiation dose rate” (radiation level) was introduced. Dose rates are measured in roentgens per hour (R/h), small dose rates are measured in milliroentgens per hour (mR/h).
Gradually, radiation dose rates (radiation levels) decrease. Thus, dose rates (radiation levels) are reduced. Thus, dose rates (radiation levels) measured 1 hour after a ground-based nuclear explosion will decrease by half after 2 hours, by 4 times after 3 hours, by 10 times after 7 hours, and by 100 times after 49 hours. .
The degree of radioactive contamination and the size of the contaminated area of the radioactive trace during a nuclear explosion depend on the power and type of explosion, meteorological conditions, as well as the nature of the terrain and soil. The dimensions of the radioactive trace are conventionally divided into zones (diagram No. 1 p. 57)).
Danger zone. At the outer boundary of the zone, the radiation dose (from the moment radioactive substances fall out of the cloud onto the area until their complete decay is 1200 R, the radiation level 1 hour after the explosion is 240 R/h.
Highly infested area. At the outer border of the zone, the radiation dose is 400 R, the radiation level 1 hour after the explosion is 80 R/h.
Moderate infection zone. At the outer boundary of the zone, the radiation dose 1 hour after the explosion is 8 R/h.
As a result of exposure to ionizing radiation, as well as when exposed to penetrating radiation, people experience radiation sickness. A dose of 100-200 R causes radiation sickness of the first degree, a dose of 200-400 R causes radiation sickness of the second degree, a dose of 400-600 R causes radiation sickness. third degree, dose over 600 R - radiation sickness of the fourth degree.
A single dose of irradiation up to 50 R over four days, as well as multiple irradiation up to 100 R over 10 to 30 days, does not cause external signs of the disease and is considered safe.