Damage to people due to exposure to light radiation. Light radiation Damaging effect of light radiation

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.

During an air explosion of a neutron munition, 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. The rarefaction (drop in air pressure) that follows the wave and the reverse movement of 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. It is especially important during the explosion of neutron ammunition. Basements of multi-storey 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” versions 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” can have a decisive meaning.

An electromagnetic pulse disables electrical and electronic equipment and disrupts radio communications.

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 yield at different altitudes:

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  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.

  The maximum surface temperature 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 burning 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.

  Shock wave

  Most 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 movement of air and strong winds along the surface with 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. In open areas, the effect of the shock wave is reduced by various depressions, obstacles, and folds in the terrain.

  Penetrating radiation

  Electromagnetic pulse

  During a nuclear explosion, as a result of strong currents in the air ionized by radiation and light, a strong alternating electromagnetic field called an electromagnetic pulse (EMP) arises. 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 attack 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:

  1. Penetrating radiation emanating from the center of the explosion passes through extended conductive objects.
  2. Gamma quanta are scattered by free electrons, which leads to the appearance of a rapidly changing current pulse in conductors.
  3. 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

  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.

  Damage to people and animals due to radiation contamination can be caused by external and internal irradiation. 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 a large number of casualties, destruction of hazardous industries and fires, will lead to difficult conditions in the area of ​​​​its effect, which will be a secondary damaging factor. People, even those who have not received significant injuries directly from the explosion, are likely to 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 frightening view of the unfolding picture of a nuclear explosion, the catastrophic nature of the destruction and fires, the disappearance of the familiar landscape, the many mutilated, charred, dying around and decomposing corpses due to the impossibility of their burial, the death of relatives and friends, awareness of the harm caused to one’s body and the horror of impending death from developing radiation sickness. The result of such an impact among survivors of the disaster will be the development of acute psychosis, as well as claustrophobic syndromes due to the awareness of the impossibility of reaching the surface of the earth, persistent nightmare memories affecting all subsequent existence. In Japan, there is a separate word for people who were victims of nuclear bombings - “Hibakusha”.

  Government intelligence services in many countries assume [ ] that one of the goals of various terrorist groups may be to seize nuclear weapons and use them against civilians for the purpose of psychological impact, even if the physical damaging factors of a nuclear explosion are insignificant on the scale of the victim country and all of humanity. The message about a nuclear terrorist attack will be immediately disseminated by the media (television, radio, Internet, press) and will undoubtedly have a huge psychological impact on people, which terrorists can count on.

  Question No. 4. List the damaging factors of a nuclear explosion. Definition of the concept “shock wave”. Impact of shock waves on people.

  The damaging factors of a nuclear explosion include: shock wave, light radiation, penetrating radiation (ionizing radiation), radioactive contamination of the area, electromagnetic pulse and seismic (gravitational) waves.

  Shock wave- the most powerful damaging factor of a nuclear explosion. About 50% of the total explosion energy is spent on its formation during explosions of medium and large caliber ammunition. It is a zone of sharp compression of air, spreading in all directions from the center of the explosion at supersonic speed. As the distance increases, the speed quickly decreases and the wave weakens. The source of the shock wave is the high pressure at the center of the explosion, reaching billions of atmospheres. The greatest pressure occurs at the front boundary of the compression zone, which is commonly called the shock wave front.

  The damaging effect of a shock wave is determined by excess pressure, that is, the difference between normal atmospheric pressure and the maximum pressure in the shock wave front. It is measured in kilopascals (kPa) or kilograms - force per 1 cm² (kgf/cm²).

  The shock wave can cause traumatic injuries, concussions or death to unprotected people. Damages can be direct or indirect.

  Direct shock wave damage occurs as a result of exposure to excess pressure and air pressure velocity, that is, a compression zone appears, followed by a rarefaction zone. Due to the small size of a person’s body, the shock wave almost instantly covers him and subjects him to strong compression.

  People can receive indirect injuries as a result of being hit by debris from destroyed buildings and structures, glass fragments, stones, trees and other objects flying at high speed.

  When affecting people, the shock wave causes injuries of varying severity:

  Ø mild lesions occur at excess pressure of 20–40 kPa (0.2–0.4 kgf/cm²). They are characterized by transient disturbances in body functions (ringing in the ears, dizziness, headache), dislocations and bruises are possible;

  Ø Moderate lesions occur at excess pressure of 40–60 kPa (0.4-0.6 kgf/cm²). This may result in contusions, hearing damage, bleeding from the ears and nose, fractures and dislocations;

  Ø Severe injuries are possible at excess pressure of 60–100 kPa (0.6–1.0 kgf/cm²). They are characterized by severe contusions of the whole body, loss of consciousness, multiple injuries, fractures, bleeding from the nose and ears; damage to internal organs and internal bleeding are possible;

  
  

  Ø extremely severe lesions occur at excess pressure of more than 100 kPa (1 kgf/cm²).

  There are ruptures of internal organs, fractures, internal bleeding, concussion, and prolonged loss of consciousness. Ruptures are observed in organs containing large amounts of blood (liver, spleen, kidneys) filled with fluid (ventricles of the brain, urinary and gall bladder). These injuries can be fatal.

  Light radiation is a stream of visible infrared and ultraviolet rays emanating from a luminous area consisting of products of a nuclear explosion and air heated to several thousand degrees. Its formation consumes 30–35% of the total explosion energy of medium-caliber ammunition. The duration of the light emission depends on the power and type of explosion and can last up to ten seconds.

  Infrared radiation has the greatest damaging effect. The main parameter characterizing light radiation is the light pulse, that is, the amount of light energy incident on 1 cm 2 (1 m 2) of the surface perpendicular to the direction of propagation of light radiation during the glow time. The light impulse is measured in calories per 1 cm 2 (cal/cm) or kilojoules per 1 m 2 (kJ/m 2) of surface. Light radiation from a nuclear explosion causes burns upon direct exposure. Secondary burns are possible, arising from the flames of burning buildings, structures, and vegetation.

  Light radiation is absorbed by opaque materials and can cause massive fires of buildings and materials, as well as skin burns and eye damage.

  Light radiation is a stream of radiant energy in the ultraviolet, visible and infrared regions of the spectrum of electromagnetic waves.

  It appears immediately after the explosion together with the formation of a luminous region of a homothermal ball and propagates at a speed of 3·10 5 km/s. As a result, the time required for the radiant flux to pass from the point of explosion to objects located even at a distance of tens of kilometers from the explosion site is practically zero.

  Light radiation for nuclear explosions with a power of more than 10 kt, compared to a shock wave and penetrating radiation, has a larger radius of destruction of openly located personnel and various easily flammable objects.

  The source of light radiation is the luminous region of the nuclear reactor. The shape of the luminous area depends on the type of explosion; with a high air explosion it is close to spherical. The luminous area of ​​a low air explosion, deformed by the shock wave reflected from the surface of the earth, takes the form of a spherical segment. In a ground explosion, the luminous area is in contact with the surface of the earth and has the shape of a hemisphere, the radius of which is 1.2...1.3 times greater than the radius of the fireball of an air explosion of the same power.

  The main parameter characterizing the effectiveness of the damaging effect of light radiation at various distances from the center of a nuclear explosion is the light pulse.

  Light pulse U is the amount of energy of direct light radiation per 1 m 2 of a stationary and unshielded surface located perpendicular to the direction of propagation of the light flux, for the entire radiation time. The light pulse is measured in J/m 2.

  The magnitude of the light pulse depends on the TNT equivalent of the explosion, the type of explosion, the distance and the transparency of the atmosphere.

  Light radiation is attenuated due to absorption and scattering in the atmosphere. With an increase in dust content and air humidity, characterized by the appearance of haze, the attenuation of light radiation increases. The attenuation coefficient also depends on the height of the explosion H and the height of the irradiated object, H o above sea level.

  In an explosion above the clouds, the radiation traveling towards the ground will be weakened and can practically not be taken into account as a damaging factor. Moreover, this phenomenon is mainly due to the reflection of light radiation from clouds.

  During an explosion under clouds, the irradiation of ground objects increases as a result of the reflection of light radiation from the clouds. In cloudy weather, during an explosion under clouds, the increase in the irradiation pulse for ground-based objects can reach fifty percent of the direct radiation pulse; in such cases, the light radiation of the fireball sometimes affects objects that are closed from the direct light flux.

  For personnel, light radiation from a nuclear explosion can cause skin burns and eye damage. The damaging effect of light radiation is determined by the amount of energy absorbed. The energy absorbed by the object heats the irradiated surface. Therefore, the main type of damage caused by light radiation is thermal damage, which is characterized by: the degree of burn, determined by the depth of thermal damage to the skin and the severity of thermal damage, depending on the depth and area of ​​the burn, as well as its location.

  In appearance, burns from light radiation do not differ from ordinary flame burns. There are four degrees of burns and four degrees of severity of thermal injuries to humans. For example, even 1st degree burns that are extensive in area can lead to loss of combat capability, while with a more severe but limited in area burn, the victims can be returned to duty after receiving medical care. As the burn area increases, the severity of thermal injury increases.

  Light radiation from a nuclear explosion is electromagnetic radiation in the optical range in the visible, ultraviolet and infrared regions of the spectrum.
  In the zone where the damaging effect of nuclear radiation is usually considered, it is contained in the spectral range of 0.3-3 microns and includes: ultraviolet 0.3-0.4 microns; visible 0.4 -0.8 µm; infrared 0.8-3 microns spectral region.
  Thus, SNIR is thermal in nature and leads to a change in the temperature state of the irradiated objects.
  SNIR energy is absorbed by the surfaces of illuminated bodies, which heat up. The heating temperature depends on
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  many factors and can lead to charring, melting and ignition of object surfaces.
  The source of nuclear explosives is the luminous area of ​​the explosion, consisting of vapors of nuclear weapons materials and air heated to a high temperature, and in case of ground explosions - evaporated soil.
  The share of nuclear explosives accounts for 30-40% of the total energy of a nuclear explosion. In open areas, light radiation has a greater range compared to the shock wave and penetrating radiation.
  The main parameters of the nuclear reactor are: E cal - part of the total explosion energy attributable to the nuclear explosive;
  -Uc, cal/cm2 - light pulse (amount of SIYV energy,
  incident radiation per unit area of ​​a surface located perpendicular to the direction of direct radiation during the entire time of radiation). The magnitude of the light pulse is approximately directly proportional to the power of the explosion, inversely proportional to the square of the distance from the center of the explosion, and also depends on the type of explosion, the degree of transparency of the atmosphere; U, cal/cm2 - irradiation pulse (the amount of energy of the irradiated radiation falling during the entire radiation time per unit area of ​​the irradiated surface). If the irradiation conditions are unknown, assume U = Uc; E, cal/cm 2s - irradiance (the amount of energy incident on the irradiated radiation; per unit time per unit area of ​​the irradiated surface);
  -Ujj cal/cm2 - damaging pulse (irradiation pulse, in which, with a given probability, dangerous damage to the material (object) is observed, leading to loss of functional properties).
  Light radiation when exposed to people can cause burns to exposed areas of the body and protected by clothing, as well as damage to the eyes. Burns can occur either directly from radiation or from flames that arise when various materials ignite from light radiation.
  SIYAV primarily affects open areas of the body (hands, neck, face) and the eyes. There are four degrees of burns:
  194 first degree (superficial skin lesions, redness); second degree (formation of bubbles); third degree (death of the deep layers of the skin); fourth degree (charring of the skin, subcutaneous tissue, and sometimes deeper tissues).
  A first-degree burn is characterized by painful redness and slight swelling of the skin, a second-degree burn is characterized by the formation of blisters filled with clear liquid, a third-degree burn is characterized by necrosis of the skin, and a fourth-degree burn is characterized by necrosis (charring) of the skin and deeper tissues.
  Thermal injuries of the first degree of severity (mild injury) are characterized, as a rule, by a favorable outcome, but cause immediate loss of combat or working capacity.
  Thermal injuries of degree 2 (moderate) severity - up to 5% of cases can result in death, and degree 3 (severe) - 20-30%.
  Thermal injuries of grade 4 (extremely severe) usually result in death.
  SIEV causes the following types of damage to the organs of vision: burns of the eyelids and anterior parts of the eyes, burns of the fundus, temporary blindness.
  Damage to the eyelids occurs with the same damaging impulses as burns of exposed skin.
  Burns of the anterior part of the eye occur with smaller light pulses, and it is customary to distinguish burns of four degrees of severity of the conjunctiva, cornea and iris.
  Burns to the fundus of the eye are possible when a person’s gaze is directed towards the explosion. The likelihood of a person looking at the luminous area is low in a real situation. Therefore, the damage to people will be determined by burns of the eyelids and the anterior part of the eyes, while simultaneous damage to eye structures is possible, a set of which will reveal the severity and outcome of the disease.
  Temporary blindness manifests itself in reversible impairments of basic visual functions that occur with a sudden change in the brightness of the visual field. Temporary blindness usually occurs at night
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  or at dusk and does not depend on the orientation of the gaze at the moment of blinding. The duration of temporary blindness can be: at night - from a few seconds to 15-30 minutes; at dusk - from a few seconds to 5 minutes; with a damaging impulse of 10-4 - 10-2 cal/cm2.
  The degree of exposure to light radiation on buildings, structures, equipment, etc. depends on the properties of their structural materials. The degree (severity) of damage from light radiation is characterized differently depending on the characteristics of the object. Damage to flammable materials and vegetation is characterized by charring, smoldering, ignition, burning; non-combustible materials - by the magnitude of deformation, loss of strength (or other properties that determine the functioning of objects), type of structural changes in the material or phase transformations. Melting, charring and ignition of materials in one place can lead to fires.
  In populated areas, fires occur as a result of light radiation and secondary causes (destruction of heating devices, containers and pipelines with
  flammable or explosive liquids and gases, short circuits of electrical circuits, etc.) resulting from the destruction of buildings and structures.
  In forests and areas of dry vegetation, fires occur only as a result of exposure to light radiation and only during the fire season (for forests in the middle zone - from April to October).
  The likelihood of fires in the forest and their duration depend on the nature of the soil layer and the clutter of the forest.
  Fires in forest rubble can last up to 12-18 hours, in populated areas: in areas of weak and moderate destruction of buildings - up to 6-12 hours, in areas of rubble - up to 1 day.
  It is necessary to note another very important aspect of the possible consequences of the use of nuclear weapons in cities. In modern cities, a huge amount of flammable materials is concentrated (according to some calculations, 10-40 g per square centimeter of area), and not just combustible, but capable of forming hygienic substances.
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  Gantian masses of soot and other dark combustion products: plastics, oil in oil storage facilities, etc. The high number of floors in modern cities creates ideal conditions for air leaks and the occurrence of a “firestorm”. Calculations show that if a large city with a population of several million people burns down as a result of a “fire storm,” then the transparency of the atmosphere over a sufficiently large area will decrease by 10 million times.
  Protection of people from light radiation is ensured by their shelter in civil defense protective structures, vehicles, and the use of the shielding properties of trenches, ravines, embankments, walls, etc.
  Protection of objects is ensured by: increasing the reflectivity of materials (whitewashing with chalk, painting with light colors); increasing resistance to light radiation (coating with clay, sprinkling with soil, snow, impregnating wood and fabrics with fire-resistant compounds); carrying out fire-fighting measures (removing dry grass, cutting down glades and constructing firebreaks).

  At the initial stages of the existence of a shock wave, its front is a sphere with its center at the point of explosion. After the front reaches the surface, a reflected wave is formed. Since the reflected wave propagates in the medium through which the direct wave has passed, its speed of propagation turns out to be slightly higher. As a result, at some distance from the epicenter, two waves merge near the surface, forming a front characterized by approximately twice the excess pressure.

  Thus, during the explosion of a 20-kiloton nuclear weapon, the shock wave travels 1000 m in 2 seconds, 2000 m in 5 seconds, and 3000 m in 8 seconds. The front boundary of the wave is called the shock wave front. The degree of shock damage depends on the power and position of objects on it. The damaging effect of hydrocarbons is characterized by the magnitude of excess pressure.

  Since for an explosion of a given power the distance at which such a front is formed depends on the height of the explosion, the height of the explosion can be selected to obtain maximum values ​​of excess pressure over a certain area. If the purpose of the explosion is to destroy fortified military installations, the optimal height of the explosion is very low, which inevitably leads to the formation of a significant amount of radioactive fallout.

  Light radiation

  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 sphere; in a ground explosion, it is a hemisphere.

  The maximum surface temperature 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, eye damage and burns to open areas of the body and temporary blindness occur, and damage to areas of the body protected by clothing may also occur.

  Burns occur from direct exposure to light radiation on exposed skin (primary burns), as well as from burning clothing in fires (secondary burns). Depending on the severity of the injury, burns are divided into four degrees: first - redness, swelling and soreness of the skin; the second is the formation of bubbles; third - necrosis of the skin and tissues; fourth - charring of the skin.

  Fundus burns (when looking directly at the explosion) are possible at distances exceeding the radii of skin burn zones. Temporary blindness usually occurs at night and at dusk and does not depend on the direction of view at the moment of the explosion and will be widespread. During the day it appears only when looking at an explosion. Temporary blindness passes quickly, leaves no consequences, and medical attention is usually not required.

  Penetrating radiation

  Another damaging factor of nuclear weapons is penetrating radiation, which is a stream of high-energy neutrons and gamma rays generated both directly during the explosion and as a result of the decay of fission products. Along with neutrons and gamma rays, nuclear reactions also produce alpha and beta particles, the influence of which can be ignored due to the fact that they are very effectively delayed at distances of the order of several meters. Neutrons and gamma rays continue to be released for quite a long time after the explosion, affecting the radiation situation. The actual penetrating radiation usually includes neutrons and gamma quanta appearing during the first minute after the explosion. This definition is due to the fact that in a time of about one minute, the explosion cloud manages to rise to a height sufficient for the radiation flux on the surface to become practically invisible.

  The intensity of the flow of penetrating radiation and the distance at which its action can cause significant damage depend on the power of the explosive device and its design. The dose of radiation received at a distance of about 3 km from the epicenter of a thermonuclear explosion with a power of 1 Mt is sufficient to cause serious biological changes in the human body. A nuclear explosive device can be specially designed to increase the damage caused by penetrating radiation compared to the damage caused by other damaging factors (so-called neutron weapons).

  The processes occurring during an explosion at a significant altitude, where the air density is low, are somewhat different from those occurring during an explosion at low altitudes. First of all, due to the low density of air, absorption of primary thermal radiation occurs over much greater distances and the size of the explosion cloud can reach tens of kilometers. The processes of interaction of ionized particles of the cloud with the Earth’s magnetic field begin to have a significant influence on the process of formation of an explosion cloud. Ionized particles formed during the explosion also have a noticeable effect on the state of the ionosphere, making it difficult, and sometimes even impossible, for the propagation of radio waves (this effect can be used to blind radar stations).

  The damage to a person by penetrating radiation is determined by the total dose received by the body, the nature of the exposure and its duration. Depending on the duration of irradiation, the following total doses of gamma radiation are accepted, which do not lead to a decrease in the combat effectiveness of personnel: single irradiation (pulsed or during the first 4 days) -50 rad; repeated irradiation (continuous or periodic) during the first 30 days. - 100 rad, for 3 months. - 200 rad, within 1 year - 300 rad.

  Radioactive 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 activity).

  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.