Light radiation- one of the damaging factors during the explosion of a nuclear weapon, which is thermal radiation from the luminous area of ​​the explosion. Depending on the power of the ammunition, the action time ranges from fractions of a second to several tens of seconds. Causes varying degrees of burns and blinding in humans and animals; melting, charring and combustion of various materials.

Formation mechanism

Light radiation is thermal radiation emitted by the products of a nuclear explosion heated to a high temperature (~10 7 K). Due to the high density of matter, the absorption capacity of a fireball is close to 1, so the spectrum of light radiation from a nuclear explosion is quite close to the spectrum of an absolutely black body. The spectrum is dominated by ultraviolet and x-ray radiation.

Protection of civilians

Light radiation is especially dangerous because it acts directly during an explosion and people do not have time to hide in shelters.

Any opaque objects can protect from light radiation - walls of houses, automobile and other equipment, steep slopes of ravines and hills. Even thick clothing can protect you, but in this case it may catch fire.

In the event of a nuclear explosion, you should immediately take cover in any shadow from the flash or, if there is nowhere to hide, lie with your back up, feet to the explosion and cover your face with your hands - this will help to some extent reduce burns and injuries. You cannot look at the flash of a nuclear explosion or even turn your head towards it, as this can lead to severe damage to the organs of vision, including complete blindness.

Protection of military equipment

Bombers designed to carry out nuclear strikes (tactical Su-24, strategic Tu-160) are partially or completely covered with white paint, which reflects a significant part of the radiation, to protect them from light radiation. Armored vehicles provide complete protection for the crew from light radiation.

Light radiation refers to radiation in a wide range of electromagnetic wavelengths, including the visible part of the spectrum and the adjacent ultraviolet and infrared parts of the spectrum.

Up to 35% of the energy of explosions is spent on the formation of this damaging factor. During underground and underwater nuclear explosions, light radiation has no damaging effect. During ground and surface explosions, light radiation is limited only to the upper hemisphere of the fireball, the light energy of the lower hemisphere is spent on heating and evaporation of the surrounding media (soil, water). As the height of the explosion increases, due to a decrease in atmospheric density, the main characteristics of light radiation change:

1. the duration of radiation is reduced;

2. the shape and size of the luminous area changes;

3. the spectral composition changes towards increasing the ultraviolet part of the spectrum;

4. there is a transition from radiation of light energy in two phases to radiation in one phase

Light emission from a fireball occurs in two phases:

1. first - due to the glow of air in the front of the shock wave;

2. second - due to the release of hot masses from the inner layers of the ball to the surface (the temperature inside the ball can reach - 8000 o K)

In the first phase, ultraviolet radiation accounts for 32% of the radiation energy, visible - 43%, infrared - 25%, in the second phase - 2%, -28%, 70%, respectively.

The severity of a person’s burn injury is determined by three factors:

1. degree of burn;

2. area of ​​the burn;

3. localization of the burn.

When exposed to light radiation, the following damage to the organ of vision may occur:

1. temporary blindness (maladaptation);

2. nuclear ophthalmia;

3. eyelid burns;

4. burns of the anterior parts of the eyeball;

5. fundus burns (chorioretinal).

Although fundus burns can occur only when looking at the fireball of an explosion, the likelihood of chorioretinal burns is quite significant (in the uninformed population, approximately 15–20%). The magnitude of the light pulse at which a retinal burn develops is 0.1 cal/cm. A burn to the anterior parts of the eyeball develops under the same conditions as skin burns on open areas of the body.

The most significant impact on the combat effectiveness of troops will be caused by temporary blindness, which is the most widespread type of eye damage in a nuclear explosion.

Protection from light radiation is achieved:

1. use of the protective properties of the area, objects, structures (creating shadows and shielding light radiation;

2. the use of materials for uniforms and clothing in light colors, as well as their impregnation with fire-resistant substances;

3. use of special protective clothing (OZK)

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

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

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

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

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

Damaging factors of a nuclear explosion

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

Shock wave

Shock wave (SW)- an area of ​​sharply compressed air, spreading in all directions from the center of the explosion at supersonic speed.

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

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

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

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

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

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

To protect against the effects of hydrocarbons, the following should be used: trenches, cracks and trenches, reducing this effect by 1.5-2 times; dugouts - 2-3 times; shelters - 3-5 times; basements of houses (buildings); terrain (forest, ravines, hollows, etc.).

Light radiation

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

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

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

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

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

Penetrating radiation

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

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

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

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

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

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

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

Radioactive contamination (contamination)

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

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

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

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

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

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

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

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

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

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

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

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

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

Electromagnetic pulse

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

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

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

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

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

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

Nuclear explosion zones

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

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

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

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

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

The source of damage in terms of the number of dead and injured may be comparable to or greater than the source of damage during an earthquake. Thus, during the bombing (bomb power up to 20 kt) of the city of Hiroshima on August 6, 1945, most of it (60%) was destroyed, and the death toll was up to 140,000 people.

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

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

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

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

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

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.

First degree burns cause pain, redness, and swelling of the skin.

Second degree burns are characterized by blistering.

Third degree burns are characterized by skin necrosis with partial damage to the germ layer. Fourth degree burns are characterized by charring of the skin and subcutaneous tissue.

Those affected with first and second degree burns usually recover, but those with third

and fourth, with a significant portion of the skin damaged, they may die.

There are three possible types of eye damage from light radiation.

1. Temporary blindness, which can last 2 - 5 minutes during the day, and up to 30 minutes at night;

2. Burns of the fundus - occur when a person fixes his gaze on

explosion point. This can happen even at distances at which light

the radiation does not cause any burns. Fundus damage is possible with a light pulse of 6 kJ/m2;

3. Burns of the cornea and eyelids (occur at the same distances as skin burns).

The degree of influence of light radiation on the elements of an object depends on the properties of structural materials.

Protection from light radiation is simpler than from other damaging factors

nuclear explosion, since any opaque barrier, any object creating a shadow,

can serve as protection from light radiation.

Penetrating radiation is the flow of gamma radiation and neutrons emitted in

environment from the nuclear explosion zone.

Depending on the energy of gamma radiation and neutrons, they can propagate in

air in all directions at a distance of 2.5 - 3 km. Penetrating radiation duration 10

15 seconds.

The damaging effect of penetrating radiation on people is the ionization of atoms and molecules of biological tissue by gamma radiation and neutrons, 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 occurrence of a specific disease - radiation sickness.

Depending on the dose absorbed by the biological tissues of the body, four degrees of radiation sickness are distinguished (Fig. 5.6.).

The absorbed dose is characterized by the amount of energy absorbed by the tissues of the human body. Its unit of measurement in the SI system is Gray (Gy), and its non-systemic unit is rad

(1 Gy = 100 rad = 1 J/kg).

Degrees of radiation sickness

1 Degree 100 – 200 rad 2 degree 200 – 400 rad 3 degree 400 – 600 rad 4 degree more than 600 rad

Rice. 5.6. Degrees of radiation sickness depending on the dose received

Radiation sickness of the first degree - the latent period lasts 2 - 3 weeks, after

which causes malaise, general weakness, nausea, dizziness, and periodic fever. The content of white blood cells (leukocytes) in the blood decreases. First degree radiation sickness is curable.

Radiation sickness of the second degree - the latent period lasts about a week. Signs of the disease are more pronounced. With active treatment, cure occurs in 1.5 - 2

Radiation sickness of the third degree - the latent period is several hours. The disease is intense and difficult. If the outcome is favorable, recovery may

occur in 6 - 8 months.

Radiation sickness of the fourth degree is the most dangerous. Usually without treatment

ends in death within 2 weeks.

The severity of the damage depends to a certain extent on the state of the body before irradiation and

his individual characteristics.

In the elements of economic objects, under the influence of neutrons, induced activity can be formed, which, during the subsequent operation of the object, will have a damaging effect on operating personnel.

Under the influence of large doses of neutron fluxes, systems lose their functionality

radio electronics and automation.

Radioactive contamination of the area, the surface layer of the atmosphere and airspace occurs as a result of the passage of a radioactive cloud from a nuclear explosion or a gas-aerosol cloud from a radiation accident.

Sources of radioactive contamination are:

in a nuclear explosion:

fission products of nuclear explosives (Pu-239, U-235, U-238);

radioactive isotopes (radionuclides) formed in soil and other materials

under the influence of neutrons - induced activity;

unreacted part of the nuclear charge;

in case of a radiation accident:

spent nuclear fuel;

part of nuclear fuel.

In a ground-based nuclear explosion, the luminous area touches the surface of the earth and hundreds of

tons of soil instantly evaporate. The air currents rising behind the fireball pick up and raise a significant amount of dust. As a result, a powerful cloud is formed, consisting of a huge number of radioactive and inactive particles, the sizes of which range from several microns to several millimeters.

On the trail of a nuclear explosion cloud depending on the degree of infection and danger

It is customary to show four zones (A, B, C, D) of human damage on maps (diagrams), and of a radiation accident - five zones (M, A, B, C, D) of contamination.

Each zone is characterized by the radiation dose rate Rdi and the radiation dose during the period of complete decay of the radioactive substance during a nuclear explosion Dipr or the radiation dose for the first year of irradiation during radiation accidents Dipgo (characteristics of contaminated zones in

The trace of the radioactive cloud is presented in Fig. 5.7).

In case of radioactive accidents
				140 mrad/h

Zone M

Zone A

Zone B

Zone B

Zone G

During a ground nuclear explosion

Figure 5.7 Characteristics of contamination zones on the trace of a radioactive cloud

Zone M - “Radiation hazard” is applied in red during radiation accidents

in color and only in peacetime.

Zone A - “Moderate infestation” is painted in blue.

Zone B - “Severe infection” is painted in green.

Zone B - “Dangerous infection” is painted in brown.

Zone D - “Extremely Dangerous Infection” is painted in black

People who are on the trail of a cloud are injured by ionizing radiation: alpha particles (a flow of helium nuclei), beta particles (a flow of electrons), gamma rays (a flow of photons, corpuscles of radiant energy), as well as neutrons.

The risk of injury to people in open areas in the wake of a radioactive cloud decreases over time.

Radioactive contamination, like penetrating radiation, can cause radiation sickness in people. The degree of radiation sickness depends on the amount of radiation dose received and the time during which the person is exposed to radiation. There are single, repeated and acute exposure of people. Irradiation received during the first four days is considered single. Irradiation received over a period of more than four days is multiple. Acute exposure is the exposure of people to a single dose of 100 rads.

Possible consequences of human exposure depending on time and dose received

are given in table. 5.2.

Table 5.2.

Consequences of human exposure

Radiation dose	Signs of radiation damage
	Uniform
	Up to 4 days – no
	10 -30 days - no	10% of those exposed have nausea, vomiting, and a feeling of fatigue, without serious loss of performance.
	3 months – no	Mild signs of first degree radiation sickness.
	1 year – no	Radiation sickness of the second degree.
	Radiation sickness of the third degree. Without treatment, mortality is up to 100%.
	Radiation sickness of the fourth degree. In most cases fatal
More than 1000	Fulminant form of radiation sickness. Those affected die in the first days after irradiation.

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