Accidents with the release of radioactively hazardous substances presentation for a lesson on life safety (grade 8) on the topic. Presentation on the topic "accidents with the release of radioactive substances" Presentation of emergencies with the release of radioactive substances

Topic 4 – Toxicology of radioactive substances In emergency situations, large areas may be contaminated with nuclear fission products (NFP). Nuclear fission products enter the body, are carried by blood and lymph to all tissues and organs of the body, selectively accumulate in them and cause internal (incorporated) irradiation of critical organs, causing certain radiation injuries. 4.1 Routes of entry of radioactive substances into the body of animals: gastrointestinal route (with food and feed through the digestive tract); inhalation route gastrointestinal route (with food (with air through the respiratory system); diffuse route (through damaged and intact skin, mucous membranes and wounds). The potential contribution of each of the above routes to the grazing period for cattle and sheep is as follows in relative units: gastrointestinal route – 1000; inhalation route – 1; diffuse route – 0.0001. Animals occupy a special place in the general scheme of radionuclide migration, especially ruminant animals, which consume a lot of succulent and roughage from a fairly large area. (up to 100-300 m2 per 1 head), and as a result are a kind of battery and transmitter of radioactive substances to humans along the food chain: Mainly through the gastrointestinal tract they enter: alkaline elements - K, Ca, Na, Rb, Cs, I, (absorbed by 100 %)); alkaline earth elements – Sr (40-60%), Co (30%), Mg (10%), Zn (10%), Ba (5%); Po – 6%, Ru – 3%, U–3-6%, Pu – 0.01%, Zr – 0.01%. While passing through the gastrointestinal tract, alpha and beta emitting radionuclides irradiate its wall, and gamma quanta reach lymph nodes and internal organs, at this time the gastrointestinal tract becomes a critical organ. The main sites of absorption (absorption) of radionuclides are the duodenum, jejunum, colon (small intestine), ileum, proventriculus of ruminants and stomachs of monogastric animals (in descending order). At the same density of contamination of the territory with radionuclides, the amount of radionuclides entering the body of farm animals will depend on the nature of feed production on farms and on the type of diet, on the specific composition of the diet. Approximate data on feed contamination with radioactive substances per 1 feed. units, conventional units Type of feed Feed. units Contained in 1 unit. 90Sr 137Cs Oats: grain straw Barley: grain straw Spring wheat: grain straw Potatoes Fodder beets Corn for silage Alfalfa Clover 1.0 0.31 1.13 0.33 1.18 0.20 0.31 0.12 0.14 0.23 0.20 1 arb. units 16 0.9 15.0 0.6 18.7 0.8 6.2 21.5 27.5 41.2 1 arb. units 6.3 0.9 6.0 0.8 10.0 5.4 20.8 4.8 15.1 16.5 Meadow grass 0.28 19.0 47.6 Hay from natural hayfields Hay from cultivated meadows 0, 47 31.7 67.4 0.50 15.0 46.6 Inhalation intake of radionuclides The surface of the alveoli is 50 times larger than the surface of the skin, therefore the inhalation intake of radioactive substances into the body can make a significant contribution to their total intake into the body, especially in the first days after radioactive contamination of the area with gaseous and aerosol short-lived products of nuclear decay in the form of dust, fog, smoke. Penetrating into the lungs, soluble radionuclides are quickly absorbed into the blood and distributed to organs and tissues; sparingly soluble radioactive substances settle in the alveoli, penetrate into the interalveolar space and lymph nodes, which become critical organs for these radionuclides. Diffuse route of entry of radioactive substances. Entry of radioactive substances through the skin, mucous membranes and wounds. This route of entry can occur during the deposition of aerosol and solid radioactive particles on the surface of the skin; absorption through the surface of the skin can increase when exposed to chemical factors (poisonous substances), other physical factors - high temperature and infrared rays (skin burns), biological factors ( bacterial toxins and the effects of the microorganisms themselves). Gaseous radionuclides of iodine, tritium, water-soluble plutonium compounds, gaseous radon and thoron are usually absorbed through the skin and mucous membranes. The critical organ for this route of radionuclide entry is the skin and mucous membranes. 4.2 Types of distribution of radionuclides in the body of animals The behavior of radionuclides in the body of animals is determined by the following factors: 1) the biogenic significance for organisms of stable isotopes of incoming radionuclides, their affinity for certain tissues and organs: for example, calcium plays a specific role and is always part of bone and other tissues , exhibits affinity for bone tissue, iodine has a greater affinity for the thyroid gland; 2) physico-chemical properties of radionuclides - the position of elements in D.I. Mendeleev’s periodic table of elements, the valence form of the radioisotope and the solubility of the chemical compound, the ability to form colloidal compounds in the blood and tissues and other factors. Based on the type of distribution, radionuclides are divided into four main groups. Types of pH distribution in the body Type of distribution Elements Elements of group 1 period. systems - H, Li, Na, K, Rb, Cs, Ru, Cl, Br, etc. Uniform (diffuse) Alkaline earth elements: Be, Ca, Sr, Ra, Zr, Ir, F, etc. Skeletal (osteotropic ) La, Ce, Pm, Pu, Th, Mn, etc. Hepatic Types of pH distribution in the body Type of distribution Elements Bi, Sr, As, U, Se, etc. Renal I, Br, As Thyrotropic Metabolism of radionuclides Radioactive isotopes entering the body just like stable isotopes of elements, as a result of exchange they are excreted from the body in feces, urine, milk, eggs and other ways. The period of time during which half of the incoming radionuclides are eliminated from the body is called the biological half-life (Tbiol.). Radioactive isotopes that enter the body, as well as stable isotopes of elements, are excreted from the body through feces, urine, milk, eggs and other routes as a result of exchange. Metabolism of radionuclides The period of time during which half of the incoming radionuclides are eliminated from the body is called the biological half-life (Tbiol.). The time during which the activity of radionuclides in the body is halved is called the effective half-life, designated Teff. The effective elimination period is calculated using the following formula: Teff. = (Tphys Tbiol.) : (Tphys. + Tbiol). . The effective period for various radioactive isotopes varies widely: from several hours (for 24Na, 64Cu-) and days (for 131I, 32P, 35S) to tens of years (for 226Ra, 90Sr). 4.3 Classification of radionuclides according to the degree of their toxicity Radiotoxicity is the property of radioactive isotopes to cause greater or lesser pathological changes when they enter the body. It depends on their following properties: The type of radioactive transformation. With alpha decay, the absorbed dose for the same activity in an organ or tissue will be 20 times greater compared to the absorbed dose with beta decay, therefore, radiation damage in the first case will be more pronounced. With higher radiation energy from radionuclides, the degree of radio damage is higher. If an isotope during radioactive decay gives rise to a new radioactive substance or an entire family, an increase in the total absorbed dose rate increases the radiotoxicity of the element. The route of entry of radioactive substances into the body matters; the most dangerous is the digestive route of entry. With a single intake, their concentration initially increases to a maximum, and then decreases within 15-20 days. With repeated intake, the concentration of radionuclides remains high for a long time and, accordingly, the radiodamage of organisms increases. Type of distribution of radioactive elements in the body. With the selective accumulation of radioactive substances in certain organs and systems, the latter are critical and most susceptible to radioactivity. The longer the effective half-life of radionuclides, the higher the degree of radiotoxicity, since the total dose for other equal conditions increases with increasing Teff. Classification of radionuclides according to the degree of radiation hazard Group A B Degree of radiotoxicity Particularly high High Activity Bq/l Ci/l 3.7-370 10-10-10-8 210Pb, 226Ra, 232U, 238Pu, 230Th 37-3700 10-9-10 -7 106Ru, 131I, 144Ce, 210Bi, 234Th, 235U, 214Pu, 90Sr 370-37 103 V Radionuclides 10-8-10-7 Average 22Na, 32P, 35S, 36Cl, 45Ca, 59Fe, 60Co, 90Y, 92Mo , 125Sb, 137Cs, 140Ba, 96Au 370-37 103 G 10-8-10-7 Low 7Be, 14C, 18F, 57Cr, 55Fe, 64Cu, 129Te, 195Pt, 197Hg, 200Tl D  14.8 10 4 4 10- 6 Tritium (3H) and its chemical compounds

The most dangerous pollution
atmosphere and all
environment –
radioactive. It
poses a threat to
health and life of people,
animals and plants are not
only living generations,
but also their descendants because
the emergence of numerous
mutational deformities.
Sources of radioactive
pollution serves
experimental explosions
atomic and hydrogen bombs.

Causes:
Radioactive contamination occurs when:
nuclear explosion as a result
fallout of radioactive substances from
clouds of a nuclear explosion and induced
radiation due to
formation of radioactive isotopes
in the environment under the influence
instantaneous neutron and gamma radiation from a nuclear explosion; amazes
people and animals.
man-made accidents (leakages from
nuclear reactors, leaks during
transportation and storage of radioactive
waste, accidental loss
industrial and medical
radio sources, etc.) as a result
dispersion of radioactive substances;
the nature of the area's contamination depends
depending on the type of accident.

Radioactive contamination and its sources:
Sources:
1) Experimental atomic explosions,
hydrogen and neutron bombs.
2) Production related to manufacturing
thermonuclear weapons.
3) Nuclear reactors and power plants,
enterprises where radioactive materials are used
substances.
4) Radioactive decontamination stations
waste.
5) Disposal of waste from nuclear enterprises and
installations.
6) Accidents or leaks at enterprises.
7) Natural sources of radioactive
air pollution is associated with exposure to
surface of uranium ores and rocks,
having increased natural
radioactivity (granites, granodiorites,
pegmatites).

Effect of radioactivity on humans:
There are several ways
receipt of radioactive
substances into the body:
1) when inhaling air
2) through contaminated food
or water
3) through the skin
4) when infected open
wound
The most dangerous way is the first one,
because firstly, the volume
pulmonary ventilation is very
big and Secondly, values
absorption coefficient in the lungs
higher. When hit
radioactive substances into the body
any way they're already through
a few minutes are detected in
blood. If receipt
there were radioactive substances
single, then their concentration in
blood initially increases to
maximum, and then for 15-20
days is decreasing. Subsequently
development of radiation injury
manifests itself in metabolic disorders
substances with changes
relevant organ functions.
In the long term they may
observed and genetic
damage.

Chernobyl
Not only the current, but also subsequent generations will remember Chernobyl and feel the consequences of this
disasters. As a result of explosions and fire during the accident at the fourth power unit of the Chernobyl nuclear power plant from April 26 to April 10
May 1986, approximately 7.5 tons of nuclear fuel and products were released from the destroyed reactor
fission with a total activity of about 50 million Ci.

Due to the fact that the release of radionuclides
occurred for more than 10 days with changing
weather conditions, main pollution zone
has a fan-shaped, spotted character. Total
radioactive release from the Chernobyl nuclear power plant in different
80% of the territory was contaminated
Belarus, the entire northern part of the Right Bank
Ukraine and 19 regions of Russia. In general for the Russian Federation
pollution caused by the Chernobyl accident,
covers more than 57 thousand km2. Traces of Chernobyl
found in most European countries, and
also in Japan, the Philippines, and Canada.
The catastrophe has become global.

And today, a decade and a half after
Chernobyl tragedy there are contradictory
assessment of its damaging effect and damage caused
economic damage. According to published in 2000
data from 860 thousand people who participated in the liquidation
consequences of the accident, more than 55 thousand liquidators died,
tens of thousands became disabled. Half a million people up to
still lives in contaminated areas.

Accurate data about
number of irradiated
and there are no doses received.
There are no clear ones
forecasts about possible
genetic
consequences.
Thesis is confirmed
about the danger
significant impact on
organism of small doses
radiation. In the districts
exposed
radioactive
infection, steadily
the number is growing
oncological
diseases, especially
growth is expressed
cancer incidence
thyroid gland
children.

PA "Mayak"
The largest cluster currently known
radionuclides is located in the Urals, 70 km northwest of Chelyabinsk in the territory
production association "Mayak".

Here in 1948 the first
country's industrial nuclear reactor,
in 1949 - the first radiochemical
factory, first samples manufactured
atomic weapons.
Currently in production
The Mayak PA structure includes a number of
nuclear cycle production facilities, complex for
disposal of highly active
materials, storage and burial grounds
RAO. Many years of activity
"Mayak" led to the accumulation of a huge
amount of radionuclides and strong
pollution of Chelyabinsk regions,
Sverdlovsk, Kurgan and Tyumen
regions. Nuclear pollution
covered an area of ​​25 thousand km2 with
population of more than 500 thousand people.
Official data on dozens
towns and villages affected
pollution resulting from discharges
radioactive waste in the river. Techa,
appeared only in 1993.

In 1957, as a result thermal explosion containers with radioactive waste
there was a powerful release of radionuclides from
total activity 2 million Ci. An “East Ural radioactive trail” up to 110 km long appeared.
About 10 thousand people out of 19 settlements V
zone of the most severe pollution with a large
were delayed and were evacuated and relocated.

The zone of radiation contamination in the Southern Urals has expanded due to wind dispersal of radioactive
aerosols from the dry part of the technological reservoir No. 9 of the Mayak Production Association (Lake Karachay) in 1967. Currently
At this time, this reservoir contains about 120 million Ci of activity, mainly due to strontium-90 and
cesium-137. A lens of contaminated groundwater with a volume of about 4 million m3 has formed under the lake and
with an area of ​​10 km2. There is a danger of contaminated waters penetrating into other aquifers and
removal of radionuclides into the river network.

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Lesson Topic: Radioactivity and radiation hazardous objects (RHO)

Questions: 1. The concept of “radioactivity”. 2. Radiation hazardous objects.

QUESTION 1: Radioactivity is the spontaneous decay of atomic nuclei of unstable chemical elements (isotopes), accompanied by the release (radiation) of a stream of elementary particles. Ionizing radiation is the interaction of such a flow with a substance that produces the formation of ions of different signs (positive and negative). The phenomenon of radioactivity and ionizing radiation affects humans everywhere and always, this is due to the fact that natural radioactive substances are scattered throughout all materials of living and inanimate nature .

Impact on humans

QUESTION 2: Radiation dangerous object– a facility where radioactive substances are stored, processed, used or transported, in the event of an accident at which radiation exposure or radioactive contamination of people, animals and plants, objects, as well as the environment may occur natural environment in dangerous doses. 1. Nuclear power plants - 9 (Balakovskaya - in Sar. region; Beloyarskaya - in Sverd. region; Bilibinskaya - in Magadh. region; Kalininskaya - in Tver region; Kola - in Murmansk region; Leningradskaya; Smolenskaya; Kursk; Novovoronezh - in the Voronezh region) 2. Shipbuilding and ship repair plants and nuclear fleet bases - (St. Petersburg, Murmansk, Severodvinsk, Komsomolsk-on-Amur, Nakhodka, Vladivostok, Magadan, Kamchatka). 3. Enterprises for the extraction and processing of uranium. 4. Enterprises for the production of highly enriched uranium and weapons-grade plutonium. 5. Places for laying down and disposal of Navy ships and civil courts with nuclear reactors 6. Research reactors. 7. Disposal sites for radioactive materials.

The most dangerous pollution of the atmosphere and the entire environment is radioactive. It poses a threat to the health and life of people, animals and plants, not only of living generations, but also of their descendants due to the appearance of numerous mutational deformities. Sources radioactive contamination experimental explosions of atomic and hydrogen bombs serve.

Radioactive contamination occurs during: Causes: a nuclear explosion as a result of the fallout of radioactive substances from the cloud of a nuclear explosion and induced radiation caused by the formation of radioactive isotopes in the environment under the influence of instantaneous neutron and gamma radiation from a nuclear explosion; affects people and animals. man-made accidents (leaks from nuclear reactors, leaks during transportation and storage of radioactive waste, accidental losses of industrial and medical radio sources, etc.) as a result of the dispersion of radioactive substances; The nature of the area's contamination depends on the type of accident.

Radioactive contamination and its sources: Sources: 1) Experimental explosions of atomic, hydrogen and neutron bombs. 2) Production related to the manufacture of thermonuclear weapons. 3) Nuclear reactors and power plants, enterprises where radioactive substances are used. 4) Radioactive waste decontamination stations. 5) Disposal of waste from nuclear enterprises and installations. 6) Accidents or leaks at enterprises. 7) Natural sources of radioactive pollution of the atmosphere are associated with the outcrops of uranium ores and rocks with increased natural radioactivity (granites, granodiorites, pegmatites). Sources: 1) Experimental explosions of atomic, hydrogen and neutron bombs. 2) Production related to the manufacture of thermonuclear weapons. 3) Nuclear reactors and power plants, enterprises where radioactive substances are used. 4) Radioactive waste decontamination stations. 5) Disposal of waste from nuclear enterprises and installations. 6) Accidents or leaks at enterprises. 7) Natural sources of radioactive pollution of the atmosphere are associated with the outcrops of uranium ores and rocks with increased natural radioactivity (granites, granodiorites, pegmatites).

Effect of radioactivity on humans: There are several ways radioactive substances enter the body: 1) by inhaling air 2) through contaminated food or water 3) through the skin 4) when open wounds become infected. The first way is the most dangerous, since, firstly, the volume of pulmonary ventilation is very large, and secondly, the values ​​of the absorption coefficient in the lungs are higher. When radioactive substances enter the body by any route, they are detected in the blood within a few minutes. If the intake of radioactive substances was one-time, then their concentration in the blood first increases to a maximum, and then decreases during the day. Subsequently, the development of radiation injury manifests itself in metabolic disorders with changes in the corresponding functions of organs. In the long term, genetic damage can also be observed.

Medical assistance for radiation injury: First health care victims of radiation poisoning should be provided with maximum reduction harmful effects. For this purpose, victims are transported to uninfected areas or to special shelters. Initially, it is necessary to take certain actions to save the life of the victim. First of all, it is necessary to organize sanitary treatment and partial decontamination of his clothes and shoes to prevent harmful effects on the skin and mucous membranes. To do this, wash the victim’s exposed skin with water and wipe with damp swabs, wash the eyes, and rinse the mouth. When decontaminating clothing and shoes, it is necessary to use products personal protection to prevent the harmful effects of radioactive substances on the victim. It is also necessary to prevent contaminated dust from reaching other people. If necessary, the victim’s stomach is washed, and absorbent agents (activated carbon, etc.) are used.

Chernobyl Not only the current, but also future generations will remember Chernobyl and feel the consequences of this disaster. As a result of explosions and fire during the accident at the fourth power unit of the Chernobyl Nuclear Power Plant from April 26 to May 10, 1986, approximately 7.5 tons of nuclear fuel and fission products with a total activity of about 50 million Ci were released from the destroyed reactor.

Due to the fact that the release of radionuclides occurred over more than 10 days under changing weather conditions, the main contamination zone has a fan-shaped, spotty character. In total, 80% of the territory of Belarus, the entire northern part of Right Bank Ukraine and 19 regions of Russia were contaminated to varying degrees by radioactive emissions from the Chernobyl nuclear power plant. In the Russian Federation as a whole, pollution caused by the Chernobyl accident covers more than 57 thousand km 2. Traces of Chernobyl have been found in most European countries, as well as in Japan, the Philippines, and Canada. The catastrophe has become global.

And today, a decade and a half after the Chernobyl tragedy, there are conflicting assessments of its damaging effects and the economic damage caused. According to data published in 2000, out of 860 thousand people who participated in the liquidation of the consequences of the accident, more than 55 thousand liquidators died, tens of thousands became disabled. Half a million people still live in contaminated areas.

There are no exact data on the number of irradiated and received doses. There are no clear predictions about possible genetic consequences. The thesis about the danger of long-term exposure to low doses of radiation on the body is confirmed. In areas affected radioactive contamination, the number of oncological diseases is steadily increasing, the increase in the incidence of thyroid cancer in children is especially pronounced.

Here, in 1948, the country's first industrial nuclear reactor was launched, in 1949, the first radiochemical plant, and the first samples of atomic weapons were manufactured. Currently in production structure PA "Mayak" includes a number of nuclear cycle production facilities, a complex for the disposal of high-level materials, storage facilities and repositories for radioactive waste. Many years of activity of the Mayak PA led to the accumulation of a huge amount of radionuclides and severe contamination of the Chelyabinsk, Sverdlovsk, Kurgan and Tyumen regions. Radioactive contamination covered an area of ​​25 thousand km 2 with a population of more than 500 thousand people. Official data on dozens of towns and villages that have been contaminated as a result of the dumping of radioactive waste into the river. Techa appeared only in 1993.

In 1957, as a result of a thermal explosion of a container containing radioactive waste, a powerful release of radionuclides with a total activity of 2 million Ci occurred. An “East Ural radioactive trace” up to 110 km long appeared. About 10 thousand people from 19 settlements in the zone of the most severe pollution were evacuated and resettled with a long delay.

The zone of radiation contamination in the Southern Urals expanded due to the wind spread of radioactive aerosols from the dry part of the technological reservoir 9 of the Mayak Production Association (Lake Karachay) in 1967. Currently, this reservoir contains about 120 million Ci of activity, mainly due to strontium -90 and cesium A lens of contaminated groundwater with a volume of about 4 million m3 and an area of ​​10 km2 has formed under the lake. There is a danger of contaminated water penetrating into other aquifers and carrying radionuclides into the river network.

Ionizing radiation Streams of charged and neutral particles, as well as electromagnetic waves. When passing through various substances ionizing radiation causes ionization in them, i.e. the transformation of neutral, stable atoms and molecules of a substance into electrically charged particles

Alpha radiation Ionizing radiation consisting of alpha particles emitted during nuclear transformations. They spread over long distances. They are completely absorbed by a piece of paper and do not pose a danger to humans, with the exception of direct contact with skin.

Beta radiation Electron ionizing radiation emitted during nuclear transformations. A person's clothing weakens their effect by almost half. They are almost completely absorbed by window glass and any metal screen several millimeters thick. Hazardous in contact with skin.

Gamma radiation Electromagnetic ionizing radiation emitted during nuclear transformations and propagating at the speed of light. Penetrate freely through clothing, the human body and significant thicknesses of materials. This radiation is the most dangerous for humans

Natural sources of ionizing radiation Cosmic radiation (stellar explosions in the galaxy and solar flares) and natural radioactive substances located on the surface and in the interior of the Earth, in the atmosphere, water, plants and organisms of all living creatures inhabiting our planet

Artificial sources of ionizing radiation Production related to the use of radioactive isotopes, nuclear power plants, transport and research nuclear power plants, special military facilities, X-ray equipment and medical radiation therapy equipment, as well as household radiation.

Radiation sources Effective equivalent dose (whole body irradiation) Watching television programs on a color TV at a distance of about 2 m from the screen for 1.5 hours 1 µrem Three-hour viewing of color television programs every day for a year 0.5 - 0.7 µrem Exposure per year from - due to radioactive emissions from nuclear power plants in the area where the station is located 0.02 - 0.1 mrem Flight for 1 hour on an airplane flying at a speed less than the speed of sound 0.4 - 0.7 mrem Fluorography 0.01-0.05 rem Reception of radon baths 1-100 mrem Chest X-ray 0.01-0.1 rem Chest X-ray 0.2-0.4 rem Dental X-ray 0.003-0.3 rem

External irradiation Cosmic rays, as well as natural and artificial emitters located in the air, in the ground, in the walls of premises or used for industrial, scientific, medical and domestic purposes.

The higher a person is above sea level, the stronger his exposure to radiation, since the thickness and density of the air layer of the atmosphere decreases as he rises, reducing its protective properties

Internal exposure Depends on radioactive substances entering the human body with inhaled air, food, and water.

Routes for radioactive substances to enter the human body Respiratory system - into the blood, lymph, gastrointestinal tract and spread throughout the body, settling in various organs and tissues: bones, liver, spleen, thyroid gland, etc. Digestive tract - into the blood and enter the various organs person. Through the skin - for open wounds and injuries.

Radiation hazardous facility An object where radioactive substances are stored, processed, used or transported, in the event of an accident or destruction of which radiation may occur ionizing radiation or radioactive contamination of people, farm animals and plants, economic facilities, as well as the natural environment

Types of accidents with the release of radioactive substances Accidents at nuclear power plants, nuclear power plants for production and research purposes with the release of radioactive substances. Accidents involving the release (threat of release) of radioactive substances at nuclear fuel cycle enterprises. Accidents Vehicle and spacecraft with nuclear installations or a cargo of radioactive substances on board.

Accidents during industrial and testing nuclear explosions with the release (threat of release) of radioactive substances. Nuclear weapons accidents or occurrences emergency situations in places of their storage (location, installation).

Causes of accidents Equipment failure due to imperfections in the design of the installation, violations in the technology of its manufacture, installation or operation. Erroneous actions of personnel or deliberate violations of operating rules. External events (plane crashes, disaster impact various types weapons)

Phases of a radiation accident Initial phase of the accident Early phase of the accident Middle phase of the accident Late phase of the accident

Initial phase of the accident The period of time preceding the start of the release (dumping) of radiation into environment, or the period of detection of the possibility of exposure of the population outside the sanitary protection zone of the enterprise.

Early phase of the accident The period of its own release (discharge) of radioactive substances into the environment, place of residence or location of the population. Duration: in the case of a one-time release (reset) - from several minutes or hours; in the case of a prolonged release (reset) - up to several days

Middle phase of the accident The period during which there is no additional release of radioactivity from the source of release (discharge) into the environment. Duration: from several weeks to a year after the accident.

Late phase of the accident The period of return to conditions of normal life of the population. Duration: from several weeks to several years or decades, i.e. until the need for protective measures ceases.

Somatic (consequences of exposure to radiation that affect the irradiated person himself, and not his offspring) Acute radiation sickness Chronic radiation sickness Local radiation damage (radiation burn, eye cataracts, damage to germ cells)

Somatic-stochastic (difficult to detect, since they are insignificant and have a long latent period, measured in tens of years after irradiation) Reduced life expectancy Malignant changes in blood-forming cells Tumors of various organs and cells

Genetic (congenital deformities resulting from mutations, changes in hereditary properties and other disorders in the reproductive cellular structures of irradiated people)

Properties of radioactive substances There is no smell, color, taste or other external signs, because of which only devices can indicate contamination of people, animals, air, terrain, etc. Capable of causing damage not only through direct contact, but also at a distance from the source of pollution. The damaging properties of radioactive substances cannot be destroyed by chemical or any other means

Features of radioactive contamination Radioactive products easily penetrate indoors, since most of them are in a vapor or aerosol state. The greatest danger is caused by internal radiation caused by the ingress of radioactive substances into the body.

Features of radioactive contamination With a long duration of radioactive release, when the direction of the wind can change many times, there is a possibility of radioactive contamination of the area in almost all directions from the source of the accident