Radiation: types, sources, the effect of radiation on humans. Everything you wanted to know about radiation

"The attitude of people to a particular hazard is determined by how well they know it."

This material is a generalized answer to numerous questions arising from users of devices for detecting and measuring radiation in domestic conditions.
  Minimal use of the specific terminology of nuclear physics in the presentation of the material will help you freely navigate this environmental problem, not succumbing to radiophobia, but also without undue complacency.

The danger of RADIATION is real and imaginary

"One of the first discovered natural radioactive elements was called" radium "
  - translated from Latin - emitting rays. ”

Each person in the environment lurks various phenomena that affect him. These include heat, cold, magnetic and ordinary storms, heavy rains, heavy snowfalls, strong winds, sounds, explosions, etc.

Due to the presence of sensory organs assigned to him by nature, he can quickly respond to these phenomena using, for example, a canopy from the sun, clothes, shelter, medicines, screens, shelters, etc.

However, in nature there is a phenomenon to which a person, due to the lack of the necessary sensory organs, cannot immediately respond - this is radioactivity. Radioactivity is not a new phenomenon; radioactivity and its accompanying radiation (the so-called ionizing) have always existed in the Universe. Radioactive materials are part of the Earth and even a person is slightly radioactive, because in any living tissue, the smallest amounts of radioactive substances are present.

The most unpleasant property of radioactive (ionizing) radiation is its effect on the tissues of a living organism, therefore, appropriate measuring instruments are needed that would provide timely information for making useful decisions before a long time passes and undesirable or even fatal consequences appear. begins to feel not immediately, but only after some time has passed. Therefore, information on the presence of radiation and its power must be obtained as early as possible.
  Enough of riddles, however. Let's talk about what radiation and ionizing (i.e. radioactive) radiation are.

Ionizing radiation

Any medium consists of the smallest neutral particles - atoms, which consist of positively charged nuclei and negatively charged electrons surrounding them. Each atom is like a solar system in miniature: around the tiny nucleus, the orbits of the “planet” move - the electrons.
Atom core   consists of several elementary particles-protons and neutrons held by nuclear forces.

Protons   particles having a positive charge equal in magnitude to the charge of electrons.

Neutrons   neutral, non-charge particles. The number of electrons in an atom is exactly equal to the number of protons in the nucleus; therefore, each atom as a whole is neutral. The mass of the proton is almost 2000 times the mass of the electron.

The number of neutral particles (neutrons) present in the nucleus can be different for the same number of protons. Such atoms, having nuclei with the same number of protons, but differing in the number of neutrons, belong to varieties of the same chemical element, called the "isotopes" of this element. To distinguish them from each other, a number equal to the sum of all particles in the nucleus of a given isotope is assigned to the symbol of the element. So uranium-238 contains 92 protons and 146 neutrons; in uranium, 235 also has 92 protons, but 143 neutrons. All isotopes of a chemical element form a group of "nuclides." Some nuclides are stable, i.e. do not undergo any transformations, while others emitting particles are unstable and turn into other nuclides. As an example, take the uranium atom - 238. From time to time a compact group of four particles breaks out of it: two protons and two neutrons - the "alpha particle (alpha)." Uranium-238 is thus transformed into an element, the core of which contains 90 protons and 144 neutrons - thorium-234. But thorium-234 is also unstable: one of its neutrons turns into a proton, and thorium-234 turns into an element, the core of which contains 91 protons and 143 neutrons. This transformation also affects electrons moving in their orbits (beta): one of them becomes, as it were, superfluous, without a pair (proton), so it leaves the atom. The chain of numerous transformations, accompanied by alpha or beta radiation, ends with a stable lead nuclide. Of course, there are many such chains of spontaneous transformations (decays) of different nuclides. The half-life is a period of time during which the initial number of radioactive nuclei decreases on average by half.
With each act of decay, energy is released, which is transmitted in the form of radiation. Often an unstable nuclide is in an excited state and the emission of a particle does not completely eliminate the excitation; then he throws a portion of energy in the form of gamma radiation (gamma quantum). As in the case of x-rays (which differ from gamma radiation only in frequency), no particles are emitted. The whole process of spontaneous decay of an unstable nuclide is called radioactive decay, and the nuclide itself is a radionuclide.

Different types of radiation are accompanied by the release of different amounts of energy and have different penetrating power; therefore, they have a different effect on the tissues of a living organism. Alpha radiation is delayed, for example, by a sheet of paper and is practically unable to penetrate the outer layer of the skin. Therefore, it does not pose a hazard until radioactive substances emitting alpha particles enter the body through an open wound, with food, water or with inhaled air or steam, for example, in a bath; then they become extremely dangerous. A beta particle has a greater penetrating ability: it passes into the body tissue to a depth of one or two centimeters or more, depending on the amount of energy. The penetrating power of gamma radiation, which propagates at the speed of light, is very high: only a thick lead or concrete slab can hold it. Ionizing radiation is characterized by a number of measurable physical quantities. These include energy values. At first glance, it might seem that they are enough to record and evaluate the effects of ionizing radiation on living organisms and humans. However, these energy values \u200b\u200bdo not reflect the physiological effect of ionizing radiation on the human body and other living tissues, are subjective, and are different for different people. Therefore, averaged values \u200b\u200bare used.

Sources of radiation are natural, present in nature, and independent of humans.

It has been established that of all natural sources of radiation, the greatest danger is represented by radon, a heavy gas without taste, odor, and yet invisible; with their daughter products.

Radon is released everywhere from the earth's crust, but its concentration in the outside air varies significantly for different points of the globe. Paradoxical as it may seem at first glance, a person receives the main radiation from radon while in a closed, unventilated room. Radon is concentrated in indoor air only when they are sufficiently isolated from the external environment. Seeping through the foundation and floor from the ground, or, less commonly, being released from building materials, radon accumulates in the room. Sealing rooms for the purpose of warming only aggravates the matter, since the release of radioactive gas from the room is even more difficult. The radon problem is especially important for low-rise buildings with careful sealing of rooms (in order to preserve heat) and the use of alumina as an additive to building materials (the so-called “Swedish problem”). The most common building materials — wood, brick, and concrete — emit relatively little radon. Granite, pumice, products from alumina raw materials, phosphogypsum have much greater specific radioactivity.

Another, usually less important, source of radon in the premises is water and natural gas used for cooking and heating homes.

The concentration of radon in commonly used water is extremely low, but water from deep wells or artesian wells contains a lot of radon. However, the main danger does not come from drinking water, even with a high content of radon in it. Usually people consume most of the water in food and in the form of hot drinks, and when boiling water or cooking hot dishes, radon almost completely disappears. A much greater danger is the ingress of water with a high content of radon into the lungs along with inhaled air, which most often occurs in a bathroom or steam room (steam room).

Radon penetrates into natural gas underground. As a result of the preliminary processing and during the storage of the gas before it is delivered to the consumer, most of the radon evaporates, but the concentration of radon in the room can significantly increase if the stoves and other heating gas appliances are not equipped with an exhaust hood. In the presence of supply and exhaust ventilation, which communicates with the outside air, the concentration of radon in these cases does not occur. This applies to the house as a whole - focusing on the readings of radon detectors, you can set the ventilation mode of the premises, completely eliminating the threat to health. However, given that the release of radon from the soil is seasonal, it is necessary to control the effectiveness of ventilation three to four times a year, avoiding exceeding the norms of radon concentration.

Other sources of radiation, unfortunately with potential danger, are created by man himself. Sources of artificial radiation are artificial radionuclides, beams of neutrons and charged particles created using nuclear reactors and accelerators. They received the name of technogenic sources of ionizing radiation. It turned out that along with a dangerous character for humans, radiation can be put at the service of humans. Here is a far from complete list of radiation applications: medicine, industry, agriculture, chemistry, science, etc. A calming factor is the controlled nature of all activities related to the receipt and use of artificial radiation.

Especially in terms of their impact on humans are tests of nuclear weapons in the atmosphere, accidents at nuclear power plants and nuclear reactors and the results of their work, which are manifested in radioactive fallout and radioactive waste. However, only emergencies, such as the Chernobyl accident, can have uncontrolled effects on humans.
  The rest of the work is easily controlled at a professional level.

When radioactive fallout occurs in some parts of the Earth, radiation can enter the human body directly through agricultural production and nutrition. Protecting yourself and your loved ones from this danger is very simple. When buying milk, vegetables, fruits, herbs, and any other products, it will not be out of place to turn on the dosimeter and bring it to the purchased products. No radiation is visible - but the device will instantly detect the presence of radioactive contamination. Such is our life in the third millennium - the dosimeter becomes an attribute of everyday life, like a handkerchief, a toothbrush, soap.

INFLUENCE OF IONIZING RADIATION ON THE TISSUE OF THE ORGANISM

The damage caused in a living organism by ionizing radiation will be the greater, the more energy it transfers to tissues; the amount of this energy is called the dose, by analogy with any substance entering the body and completely absorbed by it. The body can receive a dose of radiation regardless of whether the radionuclide is outside the body or inside it.

The amount of radiation energy absorbed by the irradiated body tissues, in terms of unit mass, is called the absorbed dose and is measured in Gray. But this value does not take into account the fact that at the same absorbed dose, alpha radiation is much more dangerous (twenty times) than beta or gamma radiation. The dose recalculated in this way is called the equivalent dose; it is measured in units called sievert.

It should also be noted that some parts of the body are more sensitive than others: for example, with the same equivalent dose of radiation, the occurrence of cancer in the lungs is more likely than in the thyroid gland, and irradiation of the genital glands is especially dangerous because of the risk of genetic damage. Therefore, human radiation doses should be considered with different factors. Multiplying the equivalent doses by the corresponding coefficients and summing over all organs and tissues, we obtain the effective equivalent dose, reflecting the total radiation effect for the body; she is also measured in sievert.

Charged particles.

Alpha and beta particles penetrating the body’s tissue lose energy due to electrical interactions with the electrons of those atoms near which they pass. (Gamma radiation and x-rays transmit their energy to matter in several ways, which ultimately also lead to electrical interactions).

Electrical interactions.

For a time of the order of ten trillion seconds after the penetrating radiation reaches the corresponding atom in the body’s tissue, an electron is detached from this atom. The latter is negatively charged, so the rest of the initially neutral atom becomes positively charged. This process is called ionization. The detached electron can further ionize other atoms.

Physico-chemical changes.

Both a free electron and an ionized atom usually cannot stay in this state for a long time and for the next ten billionths of a second they participate in a complex chain of reactions, as a result of which new molecules are formed, including such extremely reactive ones as “free radicals”.

Chemical changes.

Over the next millionths of a second, the formed free radicals react with each other and with other molecules and, through a chain of reactions that have not yet been fully studied, can cause chemical modification of the biologically important molecules necessary for the normal functioning of the cell.

Biological effects.

Biochemical changes can occur both a few seconds and decades after irradiation and cause immediate death of cells or changes in them.

RADIOACTIVITY MEASUREMENT UNITS
Becquerel (Bq, Bq);    Curie (Ki, C)	1 Bq \u003d 1 decay per second.    1 Ki \u003d 3.7 x 10 10 Bq	Units of radionuclide activity.    They represent the number of decays per unit time.
Gray (Gr, Gy);    Glad (glad rad)	1 Gy \u003d 1 J / kg    1 rad \u003d 0.01 Gy	Units of absorbed dose.    They represent the amount of energy of ionizing radiation absorbed by the unit mass of a physical body, such as body tissues.
Sievert (Sv, Sv)    Baer (ber, rem) - "biological equivalent of X-ray"	1 Sv \u003d 1 Gy \u003d 1 J / kg (for beta and gamma)    1 μSv \u003d 1/1000000 Sv    1 ber \u003d 0.01 Sv \u003d 10 mSv Units of equivalent dose.	Units of equivalent dose.    They are a unit of absorbed dose multiplied by a coefficient that takes into account the unequal danger of different types of ionizing radiation.
Gray per hour (Gy / h); Sievert per hour (Sv / h); X-ray per hour (R / h)	1 Gy / h \u003d 1 Sv / h \u003d 100 R / h (for beta and gamma) 1 μS Sv / h \u003d 1 μGy / h \u003d 100 μR / h 1 μR / h \u003d 1/1000000 R / h	Unit dose rate.    They are the dose received by the body per unit time.

For information, and not for intimidation, especially people who decide to devote themselves to working with ionizing radiation, you should know the maximum permissible doses. The radioactivity units are shown in Table 1. According to the conclusion of the International Commission on Radiation Protection in 1990, harmful effects can occur with equivalent doses of at least 1.5 Sv (150 rem) received during the year, and in cases of short-term exposure, at doses higher 0.5 Sv (50 rem). When radiation exceeds a certain threshold, radiation sickness occurs. Distinguish between chronic and acute (with a single massive exposure) form of this disease. The severity of acute radiation sickness is divided into four degrees, ranging from a dose of 1-2 Sv (100-200 rem, 1st degree) to a dose of more than 6 Sv (600 rem, 4th degree). A fourth degree may result in death.

Doses received under normal conditions are negligible compared to those indicated. The equivalent dose rate generated by natural radiation ranges from 0.05 to 0.2 μSv / h, i.e. from 0.44 to 1.75 mSv / year (44-175 mber / year).
  In medical diagnostic procedures - x-rays, etc. - A person receives another 1.4 mSv / year.

Since radioactive elements are present in small doses in brick and concrete, the dose increases by another 1.5 mSv / year. Finally, due to the emissions of modern coal-fired thermal power plants, and when flying on an airplane, a person receives up to 4 mSv / year. In total, the existing background can reach 10 mSv / year, but on average it does not exceed 5 mSv / year (0.5 rem / year).

Such doses are completely harmless to humans. The dose limit in addition to the existing background for a limited part of the population in areas of increased radiation is set at 5 mSv / year (0.5 rem / year), i.e. with 300x margin. For personnel working with sources of ionizing radiation, the maximum permissible dose of 50 mSv / year (5 rem / year), i.e. 28 μSv / h at 36-hour workweek.

According to the hygiene standards NRB-96 (1996), the permissible dose rate levels for external exposure of the whole body from man-made sources for the permanent residence of persons from the staff are 10 μGy / h, for residential premises and the territory where people from the population are constantly located - 0 , 1 μGy / h (0.1 μSv / h, 10 μR / h).

WHAT THE RADIATION MEASURES

A few words about the registration and dosimetry of ionizing radiation. There are various methods of registration and dosimetry: ionization (associated with the passage of ionizing radiation in gases), semiconductor (in which the gas is replaced by a solid), scintillation, luminescent, photographic. These methods are the basis of the work. dosimeters   radiation. Among gas-filled ionizing radiation sensors, ionization chambers, fission chambers, proportional counters and geiger-Muller counters   . The latter are relatively simple, the cheapest, and not critical to working conditions, which led to their widespread use in professional dosimetry equipment designed to detect and evaluate beta and gamma radiation. When a Geiger-Muller counter serves as a sensor, any ionizing particle falling into the sensitive volume of the counter becomes an independent discharge. It falls into the sensitive volume! Therefore, alpha particles are not registered, because they cannot get there. Even when registering beta particles, it is necessary to bring the detector closer to the object to make sure that there is no radiation, because in air, the energy of these particles may be weakened, they may not overcome the device’s body, will not fall into the sensitive element and will not be detected.

Doctor of Physical and Mathematical Sciences, Professor MEPhI N.M. Gavrilov
  article is written for the company "Quart-Rad"

Radiation is radiation invisible to the human eye, which nevertheless has a powerful effect on the body. Unfortunately, the effects of exposure on humans are extremely negative.

Initially, radiation affects the body from the outside. It comes from the natural radioactive elements that are in the earth, and also falls on the planet from space. External radiation also comes in microdoses from building materials, medical x-ray machines. Large doses of radiation can be found in nuclear power plants, special physics laboratories and uranium mines. Testing sites for nuclear weapons and landfills for radioactive waste are also extremely dangerous.

To a certain extent, our skin, clothing, and even homes protect against the above radiation sources. But the main danger of radiation lies in the fact that radiation can be not only external, but also internal.

Radioactive elements can penetrate with air and water, through cuts in the skin and even through the tissues of the body. In this case, the radiation source acts much longer - until it is removed from the human body. It is impossible to protect oneself from it with a lead plate and it is impossible to drive away, which makes the situation even more dangerous.

Radiation dosage

In order to determine the radiation power and the degree of radiation exposure on living organisms, several measurement scales were invented. First of all, the power of the radiation source in Gray and Rada is measured. Everything is quite simple here. 1 Gy \u003d 100R. This is how the level of exposure is determined using a Geiger counter. An X-ray scale is also used.

But do not assume that these indications reliably indicate the degree of danger to health. It is not enough to know the radiation power. The effect of radiation on the human body also varies with the type of radiation. There are 3 of them:

1. Alpha. These are heavy radioactive particles - neutrons and protons, which are most harmful to humans. But they have a small breakdown power and are not able to penetrate even through the upper layers of the skin. But if there are wounds or suspended particles in the air,
2. Beta. These are radioactive electrons. Their piercing ability is 2 cm of skin.
3. Gamma. These are photons. They freely penetrate the human body, and protection is possible only with lead or a thick layer of concrete.

Radiation exposure occurs at the molecular level. Irradiation leads to the formation of free radicals in the cells of the body, which begin to destroy the surrounding substances. But, given the uniqueness of each organism and the uneven sensitivity of organs to the effects of radiation on humans, scientists had to introduce the concept of an equivalent dose.

To determine why radiation in one dose or another is dangerous, the radiation power in Rada, X-rays and Gray is multiplied by a quality factor.

For alpha radiation, it is 20, and for Beta and Gamma it is 1. X-rays also have a coefficient of 1. The result is measured in Baer and Sievert. With a coefficient of unity, 1 Baer is equal to one Rad or X-ray, and 1 Sievert is equal to one Gray or 100 Baram.

To determine the degree of impact of the equivalent dose on the human body, one had to introduce another risk factor. For each organ, it differs, depending on how radiation affects individual body tissues. For the body as a whole, it is equal to unity. Thanks to this, it was possible to compile a scale of the danger of radiation and its impact on humans with a single exposure:

• 100 Sievert. This is a quick death. After a few hours, and in the best case of days, the nervous system of the body ceases to function.
• 10-50 is a lethal dose, as a result of which a person will die from numerous internal hemorrhages after several weeks of torment.
• 4-5 Sievert - Mortality is about 50%. Due to bone marrow damage and impaired blood formation, the body dies after a couple of months or less.
• 1 Sievert. It is with this dose that radiation sickness begins.
• 0.75 Sievert. Short-term changes in the composition of the blood.
• 0.5 - this dose is considered sufficient to cause the development of cancer. But there are usually no other symptoms.
• 0.3 Sievert. This is the power of the device when receiving an x-ray of the stomach.
• 0.2 Sievert. This is a safe level of radiation acceptable when working with radioactive materials.
• 0.1 - with this radiation background, uranium is mined.
• 0.05 Sievert. The rate of background exposure to medical equipment.
• 0.005 Sievert. Permissible radiation level near nuclear power plants. This is also the annual exposure rate for civilians.

Consequences of radiation exposure

The dangerous effect of radiation on the human body is caused by exposure to free radicals. They are formed at the chemical level due to exposure to radiation and affect primarily rapidly dividing cells. Accordingly, blood-forming organs and the reproductive system are more affected by radiation.

But the radiation effects of human exposure are not limited to this. In the case of delicate tissues of mucous and nerve cells, their destruction occurs. Because of this, a variety of mental disorders can develop.

Often, due to the effect of radiation on the human body, vision suffers. With a large dose of radiation, blindness due to radiation cataract may occur.

Other body tissues undergo qualitative changes, which is no less dangerous. It is because of this that the risk of cancer increases many times. Firstly, the structure of tissues is changing. And secondly, free radicals damage a DNA molecule. Due to this, cell mutations develop, which leads to cancer and tumors in various organs of the body.

The most dangerous thing is that these changes can persist in descendants, due to damage to the genetic material of germ cells. On the other hand, the reverse effect of radiation on humans is also possible - infertility. Also, in all cases without exception, radiation exposure leads to rapid cell deterioration, which accelerates the aging of the body.

Mutations

The plot of many science fiction stories begins with how radiation leads to a mutation of a person or animal. Usually a mutagenic factor gives the protagonist a variety of supernormal abilities. In reality, radiation affects a little differently - first of all, the genetic consequences of radiation affect future generations.

Due to disturbances in the chain of the DNA molecule caused by free radicals, the fetus may develop various abnormalities associated with problems of internal organs, external deformities or mental disorders. Moreover, this violation may extend to future generations.

The DNA molecule is not only involved in human reproduction. Each cell of the body is divided according to the program laid down in the genes. If this information is damaged, the cells begin to divide incorrectly. This leads to the formation of tumors. Usually it is restrained by the immune system, which tries to limit the damaged area of \u200b\u200btissue, and ideally to get rid of it. But due to immunosuppression caused by radiation, mutations can spread uncontrollably. Because of this, tumors begin to metastasize, turning into cancer, or grow and press on internal organs, such as the brain.

Leukemia and other cancers

Due to the fact that the effect of radiation on human health primarily affects the blood-forming organs and the circulatory system, the most common consequence of radiation sickness is leukemia. It is also called "blood cancer." Its manifestations affect the whole body:

1. A person loses weight, while there is no appetite. He is constantly accompanied by muscle weakness and chronic fatigue.
2. Joint pains appear, they begin to react more strongly to environmental conditions.
3. The lymph nodes become inflamed.
4. The liver and spleen are enlarged.
5. Difficulty breathing.
6. Purple rashes are found on the skin. A person often sweats profusely, bleeding may open.
7. Immunodeficiency is manifested. Infections freely penetrate the body, which often causes fever.

Prior to the events in Hiroshima and Nagasaki, doctors did not consider leukemia as a radiation disease. But 109 thousand Japanese examined confirmed the connection between radiation and cancer. It also turned out the probability of damage to certain organs. In the first place was leukemia.

Then the radiation effects of human exposure most often lead to:

1. Mammary cancer. Every hundredth woman who has experienced a strong radiation exposure is affected.
2. Thyroid cancer. It also affects 1% of the exposed.
3. Lungs' cancer. This variety manifests itself most strongly in irradiated miners of uranium mines.

Fortunately, modern medicine can very well cope with oncological diseases in the early stages, if the effect of radiation on human health was short-term and rather weak.

What affects the effects of exposure

The effect of radiation on living organisms varies greatly from the power and type of radiation: alpha, beta or Gamma. Depending on this, the same dose of radiation can be practically safe or lead to sudden death.

It is also important to understand that the effects of radiation on the human body are rarely simultaneous. Getting a dose of 0.5 Sievert at a time is dangerous, and 5-6 is deadly. But after making a few x-rays of 0.3 Sievert for a certain time, a person allows the body to cleanse itself. Therefore, the negative effects of radiation exposure simply do not occur, since with a total dose of several Sievert, only a small part of the radiation will act on the body at a time.

In addition, the various effects of radiation on humans are highly dependent on the individual characteristics of the body. A healthy body resists the damaging effects of radiation for longer. But it is best to ensure the safety of radiation for humans as little as possible in contact with radiation to minimize damage.

The main literature

II. What is radiation?

III. Basic terms and units.

IV. The effect of radiation on the human body.

V. Sources of radiation:

1) natural sources

2) man-made sources (man-made)

I. Introduction

Radiation plays a huge role in the development of civilization at this historical stage. Thanks to the phenomenon of radioactivity, a significant breakthrough was made in the field of medicine and in various industries, including energy. But at the same time, the negative aspects of the properties of radioactive elements began to manifest themselves more clearly: it turned out that the effect of radiation on the body can have tragic consequences. A similar fact could not pass by the attention of the public. And the more it became known about the effect of radiation on the human body and the environment, the more contradictory became the opinions about how much role radiation should play in various areas of human activity.

Unfortunately, the lack of reliable information causes an inadequate perception of this problem. Newspaper stories of six-legged lambs and two-headed babies sow panic in wide circles. The problem of radiation pollution has become one of the most pressing. Therefore, it is necessary to clarify the situation and find the right approach. Radioactivity should be considered as an integral part of our life, but without knowledge of the laws of processes associated with radiation, it is impossible to really assess the situation.

To this end, special international organizations are created to deal with radiation problems, including the International Commission on Radiation Protection (ICRP), which has existed since the late 1920s, as well as the Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), created in 1955 as part of the UN. In this work, the author made extensive use of the data presented in the brochure “Radiation. Doses, effects, risk ”prepared on the basis of the research materials of the committee.

II. What is radiation?

Radiation has always existed. Radioactive elements have been part of the Earth since the beginning of its existence and continue to be present to this day. However, the very phenomenon of radioactivity was discovered only a hundred years ago.

In 1896, the French scientist Henri Becquerel accidentally discovered that after prolonged contact with a piece of a mineral containing uranium, traces of radiation appeared on the photographic plates after development. Later, Marie Curie (author of the term “radioactivity”) and her husband Pierre Curie became interested in this phenomenon. In 1898, they discovered that as a result of radiation, uranium turns into other elements, which young scientists called polonium and radium. Unfortunately, people who are professionally involved in radiation exposed their health and even life to danger due to frequent contact with radioactive substances. Despite this, research continued, and as a result, humanity has very reliable information about the process of reactions in radioactive masses, largely due to structural features and atomic properties.

It is known that the atom consists of three types of elements: negatively charged electrons move in orbits around the nucleus - tightly coupled positively charged protons and electrically neutral neutrons. Chemical elements are distinguished by the number of protons. The same number of protons and electrons determines the electrical neutrality of the atom. The number of neutrons can vary, and isotope stability changes depending on this.

Most nuclides (nuclei of all isotopes of chemical elements) are unstable and are constantly turning into other nuclides. The transformation chain is accompanied by radiation: in a simplified form, the emission of two protons and two neutrons (a-particles) by a nucleus is called alpha radiation, the emission of an electron is called beta radiation, both of which occur with the release of energy. Sometimes an additional emission of pure energy, called gamma radiation, occurs.

III. Basic terms and units.

(NKDAR terminology)

Radioactive decay   - the whole process of spontaneous decay of an unstable nuclide

Radionuclide   - unstable nuclide capable of spontaneous decay

Isotope half-life   - time for which on average half of all radionuclides of a given type decay in any radioactive source

The radiation activity of the sample   - the number of decays per second in a given radioactive sample; unit - becquerel (Bq)

« Absorbed Dose *   - the energy of ionizing radiation absorbed by the irradiated body (body tissues), in terms of unit mass

Equivalent dose** - absorbed dose, multiplied by a coefficient reflecting the ability of this type of radiation to damage body tissues

Effective equivalent dose***   - equivalent dose multiplied by a coefficient that takes into account the different sensitivity of various tissues to radiation

Collective effective equivalent dose****   - effective equivalent dose received by a group of people from any source of radiation

Complete collective effective equivalent dose   - the collective effective equivalent dose that generations of people will receive from any source for the entire time of its further existence ”(“ Radiation ... ”, p.13)

IV. The effect of radiation on the human body

The effect of radiation on the body can be different, but almost always it is negative. In small doses, radiation can become a catalyst for processes leading to cancer or genetic disorders, and in large doses it often leads to complete or partial death of the body due to destruction of tissue cells.

————————————————————————————–

* gray (gr)

**   SI unit of measure - sievert (Sv)

***   SI unit of measure - sievert (Sv)

****   SI unit of measure - man-sievert (man-Sv)

The difficulty in tracking the sequence of processes caused by irradiation is explained by the fact that the consequences of irradiation, especially at low doses, may not occur immediately, and often it takes years or even decades to develop a disease. In addition, due to the different penetrating power of different types of radioactive radiation, they have an unequal effect on the body: alpha particles are the most dangerous, but even a sheet of paper is an insurmountable barrier to alpha radiation; beta radiation is able to pass into the body tissue to a depth of one or two centimeters; the most harmless gamma radiation is characterized by the highest penetrating ability: it can be delayed only by a thick plate of materials having a high absorption coefficient, for example, of concrete or lead.

The sensitivity of individual organs to radiation is also different. Therefore, in order to obtain the most reliable information about the degree of risk, it is necessary to take into account the corresponding tissue sensitivity coefficients when calculating the equivalent radiation dose:

0,03 - bone tissue

0.03 - thyroid gland

0.12 - red bone marrow

0.12 - light

0.15 - mammary gland

0.25 - ovaries or testes

0.30 - other fabrics

1.00 - the body as a whole.

The likelihood of tissue damage depends on the total dose and on the dosage size, since thanks to the reparative abilities, most organs are able to recover from a series of small doses.

However, there are doses at which a lethal outcome is almost inevitable. So, for example, doses of the order of 100 Gy lead to death in a few days or even hours due to damage to the central nervous system, from hemorrhage as a result of a radiation dose of 10-50 Gy, death occurs in one to two weeks, and a dose of 3-5 Gy threatens turn out to be fatal to about half the exposed. Knowledge of the specific reaction of the body to certain doses is necessary to assess the effects of large doses of radiation during accidents of nuclear installations and devices or the danger of radiation when staying in areas of increased radiation for a long time, both from natural sources and in the event of radioactive contamination.

The most common and serious damage caused by radiation, namely cancer and genetic disorders, should be considered in more detail.

In the case of cancer, it is difficult to assess the likelihood of the disease as a result of exposure. Any, even the smallest dose, can lead to irreversible consequences, but this is not predetermined. However, it was found that the likelihood of illness increases in direct proportion to the dose.

Among the most common cancers caused by radiation, leukemia stands out. Estimating the likelihood of a fatal outcome in leukemia is more reliable than similar estimates for other types of cancer. This can be explained by the fact that leukemia is the first to manifest itself, causing death on average 10 years after the moment of exposure. Leukemia “in popularity” is followed by breast cancer, thyroid cancer, and lung cancer. The stomach, liver, intestines, and other organs and tissues are less sensitive.

The impact of radiological radiation is sharply enhanced by other adverse environmental factors (synergy phenomenon). So, the death rate from radiation among smokers is much higher.

As for the genetic consequences of radiation, they appear in the form of chromosomal aberrations (including changes in the number or structure of chromosomes) and gene mutations. Gene mutations occur immediately in the first generation (dominant mutations) or only if both parents have the same gene mutant (recessive mutations), which is unlikely.

Studying the genetic effects of radiation is even more difficult than with cancer. It is not known what the genetic damages during irradiation are, they can occur for many generations, it is impossible to distinguish them from those caused by other causes.

We have to evaluate the appearance of hereditary defects in humans according to the results of animal experiments.

In assessing the risk, NKDAR uses two approaches: the one determines the immediate effect of a given dose, and the other determines the dose at which the frequency of offspring with one or another anomaly is doubled compared to normal radiation conditions.

So, with the first approach, it was found that a dose of 1 Gy, obtained with a low radiation background by males (estimates are less certain for women), cause from 1000 to 2000 mutations, leading to serious consequences, and from 30 to 1000 chromosomal aberrations every million living newborns.

In the second approach, the following results were obtained: chronic exposure at a dose rate of 1 Gy per generation will lead to the appearance of about 2,000 serious genetic diseases for every million living newborns among children of those exposed to such radiation.

These estimates are unreliable, but necessary. The genetic consequences of exposure are expressed in quantitative terms such as a reduction in life expectancy and the period of disability, although it is recognized that these estimates are no more than the first rough estimate. Thus, chronic exposure of a population with a dose rate of 1 Gy per generation reduces the period of working capacity by 50,000 years, and life expectancy by also 50,000 years for every million living newborns among children of the first irradiated generation; with constant irradiation of many generations, the following estimates are reached: 350,000 years and 286,000 years, respectively.

V. Sources of radiation

Now, having an idea of \u200b\u200bthe effect of radiation on living tissue, it is necessary to find out in which situations we are most exposed to this effect.

There are two methods of exposure: if radioactive substances are outside the body and irradiate it from the outside, then we are talking about external exposure. Another method of exposure - when radionuclides enter the body with air, food and water - is called internal.

Sources of radioactive radiation are very diverse, but they can be combined into two large groups: natural and artificial (created by man). Moreover, the main share of exposure (more than 75% of the annual effective equivalent dose) falls on the natural background.

Natural sources of radiation

Natural radionuclides are divided into four groups: long-lived (uranium-238, uranium-235, thorium-232); short-lived (radium, radon); long-lived single, not forming families (potassium-40); radionuclides resulting from the interaction of cosmic particles with the atomic nuclei of the Earth's substance (carbon-14).

Different types of radiation reach the Earth’s surface either from space, or come from radioactive substances located in the earth’s crust, and earth sources are responsible for an average of 5/6 annual effective equivalent doses received by the population, mainly due to internal exposure.

Radiation levels are not the same for different areas. Thus, the North and South poles, more than the equatorial zone, are exposed to cosmic rays due to the presence of the Earth’s magnetic field deflecting charged radioactive particles. In addition, the greater the distance from the earth's surface, the more intense cosmic radiation.

In other words, living in mountainous areas and constantly using air transport, we are at an additional risk of exposure. People living above 2000m above sea level receive, on average, due to cosmic rays, an effective equivalent dose several times greater than those who live at sea level. When rising from a height of 4000m (maximum altitude of people) to 12000m (maximum altitude of passenger air transport), the level of exposure increases 25 times. The approximate dose for the New York - Paris flight, according to UNSCEAR in 1985, was 50 microsievert in 7.5 hours of flight.

In total, due to the use of air transport, the Earth's population received an effective equivalent dose of about 2,000 man-Sv per year.

Terrestrial radiation levels are also distributed unevenly over the Earth's surface and depend on the composition and concentration of radioactive substances in the earth's crust. The so-called abnormal radiation fields of natural origin are formed in the case of the enrichment of certain types of rocks with uranium, thorium, in the deposits of radioactive elements in various rocks, with the modern introduction of uranium, radium, radon into surface and underground waters, and the geological environment.

According to studies conducted in France, Germany, Italy, Japan and the United States, about 95% of the population of these countries lives in areas where the dose rate varies on average from 0.3 to 0.6 millisievert per year. These data can be taken as the world average, since the environmental conditions in the above countries are different.

However, there are several “hot spots” where radiation levels are much higher. These include several areas in Brazil: the surroundings of the city of Posus di Caldas and the beaches near Guarapari, a city with a population of 12,000 people, where approximately 30,000 holidaymakers visit each year, where radiation levels reach 250 and 175 millisieverts per year, respectively. This exceeds the average by 500-800 times. Here, as well as in another part of the world, on the southwestern coast of India, a similar phenomenon is due to the increased content of thorium in the sands. The above territories in Brazil and India are the most studied in this aspect, but there are many other places with a high level of radiation, for example, in France, Nigeria, and Madagascar.

Zones of increased radioactivity are also unevenly distributed throughout Russia and are known both in the European part of the country and in the Trans-Urals, the Polar Urals, Western Siberia, Baikal, the Far East, Kamchatka, and Northeast.

Among natural radionuclides, the largest contribution (more than 50%) to the total radiation dose is made by radon and its daughter decay products (including radium). The danger of radon lies in its wide distribution, high penetration and migratory mobility (activity), decay with the formation of radium and other highly active radionuclides. The half-life of radon is relatively small and is 3.823 days. Radon is difficult to identify without the use of special equipment, as it has no color or smell.

One of the most important aspects of the radon problem is internal exposure to radon: products formed during its decay in the form of tiny particles penetrate the respiratory system, and their existence in the body is accompanied by alpha radiation. Both in Russia and in the west, a lot of attention is paid to the radon problem, as a result of the studies it turned out that in most cases the radon content in the air in rooms and in tap water exceeds the MPC. So, the highest concentration of radon and its decay products recorded in our country corresponds to an irradiation dose of 3000-4000 rem per year, which exceeds the MPC by two to three orders of magnitude. Information obtained in recent decades shows that in the Russian Federation radon is also widely distributed in the surface layer of the atmosphere, subsoil air and groundwater.

In Russia, the problem of radon is still poorly studied, but it is reliably known that in some regions its concentration is especially high. These include the so-called radon “spot” covering Onega, Ladoga lakes and the Gulf of Finland, a wide zone extending from the Middle Urals to the west, the southern part of the Western Urals, the Polar Urals, the Yenisei Ridge, the Western Baikal Region, the Amur Region, and the north of the Khabarovsk Territory , Chukotka Peninsula ("Ecology, ...", 263).

Man-made radiation sources (man-made)

Artificial sources of radiation exposure differ significantly from natural sources not only in origin. Firstly, individual doses received by different people from artificial radionuclides vary greatly. In most cases, these doses are small, but sometimes exposure to man-made sources is much more intense than natural ones. Secondly, for technogenic sources the mentioned variability is expressed much more strongly than for natural ones. Finally, pollution from man-made sources of radiation (other than radioactive fallout from nuclear explosions) is easier to control than naturally-occurring pollution.

The energy of the atom is used by man for various purposes: in medicine, for the production of energy and the detection of fires, for the manufacture of luminous watch dials, for the search for minerals and, finally, for the creation of atomic weapons.

The main contribution to pollution from artificial sources is made by various medical procedures and treatment methods associated with the use of radioactivity. The main device that no major clinic can do without is an X-ray machine, but there are many other diagnostic and treatment methods associated with the use of radioisotopes.

The exact number of people undergoing such examinations and treatment and the doses received by them are not known, but it can be argued that for many countries the use of the phenomenon of radioactivity in medicine remains almost the only technogenic source of radiation.

In principle, radiation in medicine is not so dangerous if not abused. But, unfortunately, often unjustifiably large doses are applied to the patient. Among the methods that contribute to reducing risk are reducing the area of \u200b\u200bthe X-ray beam, filtering it, removing excess radiation, proper shielding and the most commonplace, namely the health of the equipment and its proper operation.

Due to the lack of more complete data, UNSCEAR was forced to take the value of 1000 person-sv for the overall assessment of the annual collective effective equivalent dose, at least from X-ray examinations in developed countries, based on data submitted to the committee by Poland and Japan by 1985 per 1 million inhabitants. Most likely, for developing countries this value will be lower, but individual doses may be more significant. It has also been estimated that the collective effective equivalent dose from radiation for medical purposes in general (including the use of radiation therapy for cancer treatment) for the entire population of the Earth is approximately 1,600,000 people-Sv per year.

The next source of radiation created by human hands is the fallout resulting from testing nuclear weapons in the atmosphere, and despite the fact that most of the explosions were carried out in the 1950s and 60s, we are experiencing their consequences now.

As a result of the explosion, part of the radioactive substances fall out near the landfill, part is delayed in the troposphere and then travels long distances for a month, gradually settling on the ground, while remaining at approximately the same latitude. However, a large fraction of the radioactive material is ejected into the stratosphere and remains there for a longer time, also scattering over the earth's surface.

Radioactive fallout contains a large number of different radionuclides, but the largest role is played by zirconium-95, cesium-137, strontium-90 and carbon-14, whose half-lives are 64 days, 30 years (cesium and strontium) and 5730 years, respectively.

According to the UNSCEAR, the expected total collective effective equivalent dose from all nuclear explosions produced by 1985 was 30,000,000 man-Sv. By 1980, the world's population received only 12% of this dose, and the rest is still receiving and will receive millions more years.

One of the most discussed sources of radiation today is nuclear energy. In fact, during normal operation of nuclear facilities, the damage from them is negligible. The fact is that the process of generating energy from nuclear fuel is complex and takes place in several stages.

The nuclear fuel cycle begins with the extraction and enrichment of uranium ore, then the nuclear fuel itself is produced, and after the fuel has been spent at the nuclear power plant, it can sometimes be recycled through the extraction of uranium and plutonium from it. The final stage of the cycle is, as a rule, the disposal of radioactive waste.

At each stage, radioactive substances are released into the environment, and their volume can vary greatly depending on the design of the reactor and other conditions. In addition, the disposal of radioactive waste, which will continue to serve as a source of pollution for thousands and millions of years, is a serious problem.

Radiation doses vary with time and distance. The farther a person lives from the station, the lower the dose he receives.

Of the products of nuclear power plants, tritium is the most dangerous. Due to its ability to dissolve well in water and intensively evaporate, tritium accumulates in the water used in the process of energy production and then enters the cooling pond, and, accordingly, into nearby drainage ponds, underground water, and the surface layer of the atmosphere. Its half-life is 3.82 days. Its decay is accompanied by alpha radiation. Elevated concentrations of this radioisotope have been recorded in the natural environments of many nuclear power plants.

Until now, we have been talking about the normal operation of nuclear power plants, but on the example of the Chernobyl tragedy, we can conclude that there is an extremely large potential danger to nuclear energy: with any minimal failure, nuclear power plants, especially large ones, can have an irreparable impact on the entire Earth’s ecosystem.

The magnitude of the Chernobyl accident could not but arouse lively interest from the public. But few people realize the number of minor malfunctions in the operation of nuclear power plants in different countries of the world.

So, an article by M. Pronin, prepared on the basis of materials from the domestic and foreign press in 1992, contains the following data:

“... From 1971 to 1984. At nuclear power plants in Germany, 151 accidents occurred. In Japan, at 37 operating nuclear power plants from 1981 to 1985. 390 accidents were registered, 69% of which were accompanied by a leak of radioactive substances. ... In 1985, 3,000 malfunctions in systems and 764 temporary shutdowns of nuclear power plants were recorded in the USA ... ”etc.

In addition, the author of the article points out the urgency, at least for 1992, of the problem of the deliberate destruction of the nuclear fuel and energy cycle enterprises, which is associated with the unfavorable political situation in several regions. It remains to hope for the future consciousness of those who thus "digging for themselves."

It remains to indicate several artificial sources of radiation pollution that each of us faces daily.

This is, first of all, building materials, characterized by increased radioactivity. Among these materials are some varieties of granite, pumice and concrete, the production of which used alumina, phosphogypsum and calcium-silicate slag. There are cases when construction materials were produced from nuclear waste, which contradicts all standards. To the radiation emanating from the building itself, natural radiation of terrestrial origin is added. The easiest and most affordable way to at least partially protect yourself from radiation at home or at work is to ventilate the room more often.

The increased uranium content of some coals can lead to significant emissions of uranium and other radionuclides into the atmosphere as a result of fuel combustion at the thermal power station, in boiler houses, and during the operation of vehicles.

There are a huge number of commonly used items that are a source of radiation. First of all, it is a watch with a luminous dial, which gives the annual expected effective equivalent dose, 4 times higher than that due to leaks at nuclear power plants, namely 2,000 people-Sv (“Radiation ...”, 55). The equivalent dose is received by employees of the enterprises of the nuclear industry and the crews of airliners.

In the manufacture of such watches use radium. At the same time, the owner of the watch is most exposed to this risk.

Radioactive isotopes are also used in other luminous devices: input-output indicators, in compasses, telephone disks, sights, in the chokes of fluorescent lamps and other electrical appliances, etc.

In the manufacture of smoke detectors, the principle of their action is often based on the use of alpha radiation. In the manufacture of particularly thin optical lenses, thorium is used, and uranium is used to give teeth an artificial shine.

Exposure to radiation from color TVs and X-ray machines for checking passenger baggage at airports is very small.

VI. Conclusion

In the introduction, the author pointed out the fact that one of the most serious omissions today is the lack of objective information. Nevertheless, a great deal of work has already been done on the assessment of radiation pollution, and the research results are published from time to time both in the specialized literature and in the press. But to understand the problem, it is necessary to have not fragmentary data, but to clearly present the whole picture.

And she is like that.

We do not have the right and ability to destroy the main source of radiation, namely nature, and we cannot and should not refuse the advantages that our knowledge of the laws of nature and the ability to use them give us. But necessary

List of references

1. Lisichkin V.A., Shelepin L.A., Boev B.V.   The decline of civilization or the movement towards the noosphere (ecology from different angles). M .; “IT-Garant”, 1997. 352 p.

2. Miller T.   Life in the environment / Transl. from English In 3 t. T. 1. M., 1993; T.2. M., 1994.

3. Nebel B.   Environmental science: How the world works. In 2 t. / Per. from English T. 2.M., 1993.

4. Pronin M.   Be afraid! Chemistry and life. 1992. No. 4. S.58.

5. Revell P., Revell C.The environment of our habitat. In 4 kn. Prince 3. Energy problems of mankind / Per. from English M .; Science, 1995.296 s.

6. Environmental problems: what is happening, who is to blame and what to do ?: Textbook / Ed. prof. IN AND. Danilova-Danilyana. M.: Publishing House of MNEPU, 1997.332 s.

7. Ecology, nature conservation and environmental safety .: Textbook / Ed. prof. V.I. Danilova-Danilyana. In 2 book Prince 1. - M .: Publishing house of MNEPU, 1997 .-- 424 p.

International Independent

Ecological and Political Science University

A.A. Ignatiev

RADIATION HAZARD

AND THE PROBLEM OF USE OF NPP.

Full-time Department of the Faculty of Ecology

Moscow 1997

Radioactive radiation (or ionizing) is the energy that is released by atoms in the form of particles or waves of an electromagnetic nature. A person is exposed to such an impact both through natural and man-made sources.

The useful properties of radiation have allowed its successful use in industry, medicine, scientific experiments and research, agriculture and other fields. However, with the spread of the application of this phenomenon, a threat to human health has arisen. A small dose of radiation can increase the risk of serious illness.

The difference between radiation and radioactivity

Radiation, in the broad sense, means radiation, that is, the propagation of energy in the form of waves or particles. Radioactive radiation is divided into three types:

• alpha radiation - a stream of helium-4 nuclei;
• beta radiation - a stream of electrons;
• gamma radiation - a stream of high-energy photons.

The characteristic of radioactive radiation is based on their energy, transmission properties and the form of emitted particles.

Alpha radiation, which is a stream of corpuscles with a positive charge, can be delayed by a layer of air or clothing. This species practically does not penetrate the skin, but when it enters the body, for example, through cuts, it is very dangerous and adversely affects the internal organs.

Beta radiation has more energy - electrons move at high speed, and their size is small. Therefore, this type of radiation penetrates through thin clothes and skin deep into the tissue. Beta radiation can be shielded with an aluminum sheet of several millimeters or a thick wooden board.

Gamma radiation is a high-energy radiation of an electromagnetic nature that has strong penetrating power. To protect against it, you need to use a thick layer of concrete or a plate of heavy metals such as platinum and lead.

The phenomenon of radioactivity was discovered in 1896. The discovery was made by the French physicist Becquerel. Radioactivity is the ability of objects, compounds, elements to emit an ionizing study, that is, radiation. The reason for the phenomenon is the instability of the atomic nucleus, which releases energy during decay. There are three types of radioactivity:

• natural - typical for heavy elements, the serial number of which is more than 82;
• artificial - initiated specifically by nuclear reactions;
• induced - characteristic of objects that themselves become a source of radiation, if they are strongly irradiated.

Elements with radioactivity are called radionuclides. Each of them is characterized by:

• half-life;
• type of radiation emitted;
• radiation energy;
• and other properties.

Radiation sources

The human body is regularly exposed to radiation. About 80% of the amount received annually is cosmic rays. Air, water and soil contain 60 radioactive elements, which are sources of natural radiation. The inert gas radon released from the earth and rocks is considered the main natural source of radiation. Radionuclides also penetrate the human body with food. Part of the ionizing radiation to which people are exposed comes from anthropogenic sources, ranging from atomic electricity generators and nuclear reactors to radiation used to treat and diagnose radiation. Today, common artificial radiation sources are:

• medical equipment (the main anthropogenic source of radiation);
• radiochemical industry (extraction, enrichment of nuclear fuel, processing and recovery of nuclear waste);
• radionuclides used in agriculture, light industry;
• accidents at radiochemical enterprises, nuclear explosions, radiation emissions
• construction Materials.

Radiation exposure by the method of penetration into the body is divided into two types: internal and external. The latter is characteristic of radionuclides sprayed in air (aerosol, dust). They come in contact with skin or clothing. In this case, the radiation sources can be removed by flushing them. External radiation causes burns to the mucous membranes and skin. With the internal type, the radionuclide enters the bloodstream, for example, by injection into a vein or through wounds, and is removed by excretion or by therapy. Such radiation provokes malignant tumors.

The radioactive background substantially depends on the geographical location - in some regions the level of radiation can exceed hundreds of times the average.

The effect of radiation on human health

Due to the ionizing effect, radioactive radiation leads to the formation of free radicals in the human body - chemically active aggressive molecules that cause cell damage and cell death.

Especially sensitive to them are the cells of the gastrointestinal tract, reproductive and hematopoietic systems. Radiation exposure disrupts their work and causes nausea, vomiting, stool disturbance, and temperature. By acting on the tissues of the eye, it can lead to radiation cataract. The effects of ionizing radiation also include damage such as vascular sclerosis, impaired immunity, and a violation of the genetic apparatus.

The hereditary data transfer system has a fine organization. Free radicals and their derivatives can disrupt the structure of DNA - the carrier of genetic information. This leads to mutations that affect the health of future generations.

The nature of the effects of radioactive radiation on the body is determined by a number of factors:

• type of radiation;
• radiation intensity;
• individual characteristics of the body.

The results of radiation may not appear immediately. Sometimes its effects become noticeable after a significant period of time. Moreover, a large single dose of radiation is more dangerous than long-term exposure to small doses.

The absorbed amount of radiation is characterized by a quantity called Sievert (Sv).

• Normal background radiation does not exceed 0.2 mSv / h, which corresponds to 20 micro-roentgens per hour. When radiographing a tooth, a person receives 0.1 mSv.

• The lethal single dose is 6-7 Sv.

The use of ionizing radiation

Radioactive radiation is widely used in technology, medicine, science, military and nuclear industries and other spheres of human activity. The phenomenon underlies such devices as smoke detectors, electric power generators, icing detectors, air ionizers.

In medicine, radioactive radiation is used in radiation therapy for the treatment of cancer. Ionizing radiation has allowed the creation of radiopharmaceuticals. With their help, diagnostic tests are carried out. Devices for analyzing the composition of compounds and sterilization are arranged on the basis of ionizing radiation.

The discovery of radioactive radiation was revolutionary without exaggeration - the application of this phenomenon brought mankind to a new level of development. However, this also caused a threat to the environment and human health. In this regard, maintaining radiation safety is an important task of our time.

Radiation is an ionizing radiation that causes irreparable harm to everything around. People, animals, plants suffer. The biggest danger is that it is not visible to the human eye, so it is important to know about its main properties and effects in order to protect itself.

Radiation accompanies people all their lives. It is found in the environment, as well as within each of us. A huge impact are external sources. Many have heard about the accident at the Chernobyl nuclear power plant, the consequences of which are still encountered in our lives. People were not ready for such a meeting. This once again confirms that there are events in the world that are not subject to humanity.

Types of radiation

Not all chemicals are stable. In nature, there are certain elements whose nuclei transform, breaking up into separate particles with the release of a huge amount of energy. This property is called radioactivity. Scientists as a result of research have discovered several types of radiation:

1. Alpha radiation is a stream of heavy radioactive particles in the form of helium nuclei that can cause the greatest harm to others. Fortunately, they are characterized by low penetration. In airspace, they spread only a couple of centimeters. In fabric, their mileage is a fraction of a millimeter. Thus, external radiation is not dangerous. You can protect yourself using thick clothes or a piece of paper. But internal exposure is an impressive threat.
2. Beta radiation is a stream of light particles moving in the air for a couple of meters. These are electrons and positrons that penetrate the tissue by two centimeters. It is harmful in contact with human skin. However, a greater danger when exposed from the inside, but less than alpha. To protect against the influence of these particles, special containers, protective shields, a certain distance are used.
3. Gamma and X-rays are electromagnetic radiation that penetrates the body through and through. Protective equipment from such exposure includes the creation of screens of lead, the erection of concrete structures. The most dangerous of the exposures to external damage, as it affects the whole body.
4. Neutron radiation consists of a neutron flux having a higher penetration rate than gamma. It is formed as a result of nuclear reactions occurring in reactors and special research facilities. It appears during nuclear explosions and is in the waste of utilized fuel from nuclear reactors. Armor from such exposure is created from lead, iron, concrete.

All radioactivity on Earth can be divided into two main types: natural and artificial. The first includes radiation from space, soil, gases. The artificial one appeared thanks to man when using nuclear power plants, various equipment in medicine, and nuclear enterprises.

Natural sources

Natural radioactivity has always been on the planet. Radiation is present in everything that surrounds humanity: animals, plants, soil, air, water. It is believed that this small level of radiation does not have a harmful effect. Although, some scientists have a different opinion. Since people are not able to influence this danger, circumstances that increase the permissible values \u200b\u200bshould be avoided.

Varieties of natural sources

1. Cosmic radiation and solar radiation are powerful sources capable of eliminating all life on Earth. Fortunately, the planet is protected from this impact by the atmosphere. However, people tried to correct this situation by developing activities leading to the formation of ozone holes. Do not get exposed to direct sunlight for a long time.
2. Radiation from the earth's crust is dangerous near deposits of various minerals. Burning coal or using phosphorus fertilizers, radionuclides actively seep inside a person with inhaled air and the food they use.
3. Radon is a radioactive chemical element present in building materials. It is a colorless, odorless and tasteless gas. This element actively accumulates in soils and goes outside with the extraction of minerals. It enters the apartments with household gas, as well as with tap water. Fortunately, its concentration is easily reduced by constantly ventilating the premises.

Artificial sources

This species appeared thanks to people. Its action increases and spreads with their help. At the time of the outbreak of a nuclear war, the strength and power of weapons is not as terrible as the effects of radiation after explosions. Even if you are not caught in a blast wave or physical factors, radiation will kill you.

Artificial sources include:

• Nuclear weapon;
• Medical equipment;
• Waste from enterprises;
• Certain gemstones;
• Some antique items taken out of danger zones. Including from Chernobyl.

Radiation rate

Scientists have been able to establish that radiation has a different effect on individual organs and the whole organism. In order to assess the damage resulting from chronic exposure, the concept of an equivalent dose was introduced. It is calculated by the formula and is equal to the product of the dose received, absorbed by the body and averaged over a specific organ or the entire human body, by the weight factor.

The unit of measurement of the equivalent dose is the ratio of Joule to kilograms, which is called sievert (Sv). Using it, a scale was created to understand the specific danger of radiation to humanity:

• 100 Sound Instant death. The victim has several hours, a maximum of a couple of days.
• 10 to 50 Sound The injured of this nature will die in a few weeks from severe internal bleeding.
• 4-5 Sound When this amount is ingested, the body copes in 50% of cases. Otherwise, the sad consequences lead to death after a couple of months due to damage to the bone marrow and circulatory disorders.
• 1 Sound With the absorption of such a dose, radiation sickness is inevitable.
• 0.75 Sound Changes in the circulatory system for a short period of time.
• 0.5 Sound This amount is enough for the patient to develop cancer. The remaining symptoms are absent.
• 0.3 Sound This value is inherent in the apparatus for conducting x-rays of the stomach.
• 0.2 Sound Permissible level for working with radioactive materials.
• 0.1 Sound With this amount, uranium is mined.
• 0.05 Sound This value is the exposure rate of medical devices.
• 0,0005 Sound Permissible amount of radiation level near the nuclear power plant. This is also the value of the annual exposure of the population, which is equal to the norm.

Values \u200b\u200bup to 0.0003-0.0005 Sv per hour belong to a safe dose of radiation for humans. Irradiation of 0.01 Sv per hour is considered to be extremely permissible if such an effect is short-lived.

The effect of radiation on humans

Radioactivity has a huge impact on the population. Not only people who face danger face the harmful effects, but also the next generation. Such circumstances are caused by radiation at the genetic level. There are two types of influence:

• Somatic. Diseases occur in the victim who received a dose of radiation. It leads to the appearance of radiation sickness, leukemia, tumors of various organs, local radiation injuries.
• Genetic. Associated with a defect in the genetic apparatus. It appears in subsequent generations. Suffer children, grandchildren and more distant descendants. Gene mutations and chromosomal changes occur.

In addition to the negative impact, there is a favorable moment. Thanks to the study of radiation, scientists were able to create on its basis a medical examination that saves lives.

  Mutation after radiation

Effects of exposure

Upon receipt of chronic radiation in the body, recovery measures occur. This leads to the fact that the victim acquires a lower load than would have received with a single penetration of the same amount of radiation. Radionuclides are not evenly distributed inside a person. Most often affected: the respiratory system, digestive organs, liver, thyroid.

The enemy does not doze off even 4-10 years after exposure. Blood cancer can develop inside a person. He presents a special danger in adolescents under the age of 15. It has been observed that the mortality rate of people working with X-ray equipment is increased due to leukemia.

The most frequent result of radiation exposure is radiation sickness, which occurs both with a single dose and with a long one. With a large number of radionuclides leads to death. Breast and thyroid cancer is common.

A huge number of organs suffer. The vision and mental state of the victim is impaired. Miners involved in uranium mining often have lung cancer. External exposure cause terrible burns of the skin and mucous membranes.

Mutations

After exposure to radionuclides, two types of mutations are possible: dominant and recessive. The first occurs immediately after exposure. The second type is found after a large period of time not in the victim, but in his subsequent generation. Disorders caused by a mutation lead to deviations in the development of internal organs in the fetus, external deformities and a change in the psyche.

Unfortunately, mutations are poorly studied, since they usually do not immediately appear. After a while, it is difficult to understand what exactly had the dominant influence on its occurrence.