The Chernobyl disaster occurred at 1 hour 23 minutes on April 26: a reactor explosion occurred at the 4th power unit with a partial collapse of the power unit building. A strong fire started in the premises and on the roof. A mixture of the remains of the reactor core, molten metal, sand, concrete and nuclear fuel spread throughout the premises of the power unit. The explosion released a huge amount of radioactive elements into the atmosphere.

Causes of the accident

A day earlier, on April 25, the 4th power unit was shut down for preventive maintenance. During this repair, the turbogenerator was tested for run-down. The fact is that if you stop supplying superheated steam to this generator, it will be able to generate energy for a long time before it stops. This energy could be used in case of emergencies at nuclear power plants.

These were not the first tests. The previous 3 test programs were unsuccessful: the turbogenerator provided less energy than expected. Great hopes were placed on the results of the fourth tests. Omitting details, the activity of the reactor is controlled by the insertion and withdrawal of absorber rods. On Chernobyl nuclear power plant These rods had an unsuccessful design, due to which, when they were withdrawn sharply, an “end effect” occurred - the reactor power, instead of falling, increased sharply.

Unfortunately, such features of the rods were studied in detail only after the Chernobyl disaster, but operating personnel should know about the “end effect”. The personnel did not know about this, and when simulating an emergency shutdown, that same sharp increase in reactor activity occurred, leading to an explosion.

The power of the explosion is evidenced by the fact that the 3,000-ton concrete reactor cover came off, pierced the roof of the power unit, and took out a loading and unloading machine along the way.

Consequences of the accident

As a result of the Chernobyl disaster, 2 nuclear power plant employees died. 28 people died later from radiation sickness. Of the 600 thousand liquidators who took part in the work at the destroyed station, 10% died from radiation sickness and its consequences, 165 thousand became disabled.

A huge amount of equipment used during the liquidation had to be written off and left in cemeteries, right on the contaminated territory. Subsequently, the equipment slowly began to go into scrap metal and...

Huge territories were contaminated with radioactive substances. An exclusion zone was created within a radius of 30 km from the nuclear power plant: 270 thousand were resettled to other areas.

The station area was decontaminated. A protective sarcophagus was built over the destroyed power unit. The station was closed, but due to a lack of electricity, it was reopened in 1987. In 2000, under pressure from Europe, the station was finally closed, although it still performs distribution functions. The protective sarcophagus has fallen into disrepair, but there are no funds to build a new one.

The fourth power unit of the Chernobyl nuclear power plant was put into operation on March 26, 1984.

Just over two years later an accident occurred on it, which later became the largest man-made disaster in the history of the peaceful atom.

Day April 26, 1986 entered world history like the day that changed the fate of hundreds of thousands of people.

The accident left behind many victims and sick people. And once prosperous Pripyat city eventually became a ghost town.

Today, in 2018, Ukraine continues to feel the consequences accidents. And society continues to be interested in answers to basic questions about what happened. Moreover, there are plenty of such questions.

What happened on April 26, 1986?

Photos from open sources

On April 25, 1986 a stop was planned of the fourth power unit for the next scheduled preventive maintenance (PPR).

During the PPR Various tests are usually carried out equipment, both routine and non-standard.

This time the purpose of one of them was to test the so-called “turbogenerator rotor run-down” mode, proposed by the general designer as an additional emergency power supply system.

The tests were to be carried out at a power of 700-1000 MW. About a day before the accident, the reactor power was reduced to approximately 1600 MW, and also, in accordance with the program, the reactor's emergency cooling system was turned off.

Before starting the experiment, the power level fell to 30 MW. The operator tried to restore power, eventually starting the experiment below the planned level of 200 MW.

At 1:23:38 button press detected maximum emergency protection of the core - 5: the reaction did not stabilize after the start of the test, the reactor power gradually increased.

But emergency protection no longer helped - the situation got out of control. Later two explosions occurred with an interval of several seconds, as a result of which the reactor was completely destroyed. The power unit building and the roof of the turbine hall partially collapsed.

More than 30 fires occurred, the main ones were suppressed within an hour, and by 5 a.m. on April 26, the fire was extinguished.

Later, as a result of the poisoning of atomic fuel from the destroyed reactor in different parts central hall of the 4th block there was a fire of great intensity. Helicopter equipment was used to extinguish it.

Who is to blame for the accident at the Chernobyl station?

Photos from open sources

In general, various versions have been voiced over the years. We convey the essence of the main ones.

- State Commission , formed in the USSR to investigate the causes of the accident, assigned primary responsibility on operational personnel and station management.

- IAEA(International Atomic Energy Agency) created the Nuclear Safety Advisory Committee (INSAG), which initially generally supported the conclusions of the USSR State Commission.

It was argued that the accident was the result of an unlikely coincidence of a number of violations of rules and regulations by personnel, which developed into catastrophic consequences due to the reactor being brought into an unregulated state.

In particular, the station staff and management were accused of:

Conducting an experiment “at any cost.”

Removal of serviceable technological protections from operation.

Hushing up the scale of the accident in the first days.

However, in 1991 The issue of liability was examined anew and the final conclusion was already different.

It said that “the Chernobyl accident, which began due to the actions of operational personnel, acquired catastrophic proportions inadequate to them due to the unsatisfactory design of the reactor.”

Besides, those in force at the time of the accident were analyzed regulations and as a result, a number of accusations previously made against the personnel were not confirmed.

The report found many of the 1986 conclusions to be incorrect and revised "some details of the scenario" previously published.

Now most likely cause of the accident errors in the design and design of the reactor were cited. The main factors were:

Non-compliance of the reactor with safety standards and its dangerous design features.

Low quality of operating regulations in terms of safety.

Ineffectiveness of the regulatory and safety oversight regime, and a general lack of safety culture in nuclear matters.

The personnel did not have sufficient understanding of the plant features affecting safety and made a number of errors, violating existing instructions and the test program.

That is There is no single version as such - the majority is inclined to a coincidence of circumstances in the form of personnel errors and imperfections in the reactor design.

There are other, alternative versions.

Local earthquake

This version was put forward by E. Barkovsky, an employee of the Institute of Earth Physics of the Russian Academy of Sciences. The basis is a seismic shock recorded approximately at the time of the accident in the Chernobyl nuclear power plant area.

Supporters of this version argue that the shock occurred before, and not at the moment of the explosion, and the strong vibration could have been caused not by processes inside the reactor, but by an earthquake. This claim is disputed by some other scholars.

Intentional crime

A conspiracy theory, including possible sabotage or even a terrorist attack.

What are the consequences of the Chernobyl accident?

Liquidators Photos from open sources

The intense fire lasted 10 days. total emission radioactive materials in environment amounted to about 14 exabecquerels (about 380 million curies).

Radioactive contamination more than 200 thousand square meters were exposed. km, of which 70% are in Ukraine, Belarus and Russia.

Was evacuated Pripyat city, as well as the population 10 km zone around the Chernobyl nuclear power plant. Total during May 1986 out of 188 settlements in the 30-kilometer exclusion zone around the station were resettled about 116 thousand people(- about 350 thousand).

- Radioactive contamination is partially reached other countries. In particular, we are talking about Norway, Finland and Sweden.

- Exact amount The victims of the accident have not yet been named. Approximate data is about 4 thousand people who died from radiation exposure at the time of the accident. According to Greenpeace, from the Chernobyl disaster may reach 90 thousand people.

What are the objects "Shelter" and "Shelter-2"?

Object "Shelter" Chernobyl NPP Portal

By November 1986, the fourth power unit of the Chernobyl Nuclear Power Plant was built insulation structure "Shelter".

For construction 400 thousand cubic meters were used. m of concrete mixture and 7 thousand tons of metal structures. 90 thousand people were involved in the construction of the Shelter.

Unofficial name - "Sarcophagus".

During construction, the service life of the Shelter was predicted at 20 – 40 years old. After construction, it was periodically strengthened.

"Shelter-2" - an insulating structure whose task is to cover the outdated “Shelter”. Construction began in 2007. It was originally planned that the project would be ready by 2012-2013, but the completion date was delayed.

From open sources

Last date proposed commissioning – May 2018.

Chernobyl nuclear power plant dispatchers at work

April 25, 1986 was an ordinary day that did not foreshadow anything new in the work of the Chernobyl nuclear power plant. Unless an experiment was planned to test the run-down of the turbogenerator of the fourth power unit...

As usual, the Chernobyl nuclear power plant welcomed a new shift. An explosion at the Chernobyl nuclear power plant is something that no one on that fateful shift thought about. However, before the experiment began, an alarming moment appeared that should have attracted attention. But he didn’t pay attention.

Control room of the Chernobyl Nuclear Power Plant, our days

The explosion at the Chernobyl nuclear power plant was inevitable

On the night of April 25-26, the fourth power unit was preparing for preventative repairs and experiments. To do this, it was necessary to reduce the reactor power in advance. And the power was reduced to fifty percent. However, after reducing power, poisoning of the reactor with xenon, which was a product of fuel fission, was noted. No one even paid attention to this fact.

The staff was so confident in the RBMK-1000 that at times they treated it too carelessly. The explosion of the Chernobyl nuclear power plant was out of the question: it was believed that it was simply impossible. However, a reactor of this type was a rather complex installation. The peculiarities of managing his work required increased care and responsibility.

Unit 4 after the explosion

Personnel actions

To trace the moment when the explosion occurred at the Chernobyl nuclear power plant, it is necessary to delve into the sequence of actions of the personnel that night.

Almost by midnight, the controllers gave their permission to further reduce the reactor power.

Even at the beginning of the first hour of the night, all parameters of the reactor state corresponded to the stated regulations. However, after a few minutes, the reactor power dropped sharply from 750 mW to 30 mW. In a matter of seconds it was possible to increase it to 200 mW.

View of the exploded power unit from a helicopter

It is worth noting that the experiment had to be carried out at a power of 700 mW. However, one way or another, it was decided to continue the test at the existing power. The experiment was to be completed by pressing button A3, which is an emergency protection button and shuts down the reactor.

The Chernobyl disaster was an accident at the fourth reactor of the Chernobyl nuclear power plant at 1:23 a.m. on April 26, 1986. This is the largest nuclear power accident in the world and we can say that the Chernobyl tragedy is the largest technological disaster of the 20th century.

The Chernobyl Nuclear Power Plant (NPP) is located in the city of Pripyat, near the center of Chernobyl, almost at the junction of Ukraine, Belarus and Russia. That is why these 3 union republics suffered the most from the accident.

Chronology of events

On the night of April 25-26, it was planned to conduct an experiment at the fourth power unit of the Chernobyl nuclear power plant. The essence of the experiment was to reduce the power unit's power from 3200 megawatts (the nominal power of the unit) to 700 megawatts. It is precisely because of the this experiment and an accident happened.

Before we begin to understand what the Chernobyl accident is, I propose to dwell on the chronology of the events of April 25 and 26, 1986. This will allow you to track real events events that took place in those days, as well as obtain facts for further analysis.

• 01:06 - a gradual reduction in reactor power began.
• 13:05 - reactor power is reduced by 50% and amounts to 1600 MW.
• 14:00 - at the request of dispatchers, the reduction in power is stopped. A few minutes earlier, the reactor's emergency cooling system was turned off.
• 23:05 - the beginning of a new reduction in power.

• 00:28 - the reactor power drops to 500 megawatts, goes into automatic mode and suddenly drops to 30 megawatts, which is 1% of the rated power.
• 00:32 - To restore power, operators remove the rods from the reactor. At this moment there are less than 20 of them left.
• 01:07 - power stabilizes at 200 MW.
• 01:23:04 - continuation of the experiment.
• 01:23:35 - uncontrolled increase in reactor power.
• 01:23:40 - emergency button pressed.
• 01:23:44 - the actual power of the reactor was 320,000 MW, which is 100 times higher than the rated power.
• 01:24 - destruction of the upper plate weighing 1000 tons and the release of hot parts of the core.

The Chernobyl accident consisted of two explosions, as a result of which the fourth power unit was completely destroyed. The accident itself lasted a few seconds, but led to terrible consequences and the largest technological disaster of its time.

From the facts given above, it is clear that an experiment was carried out, that first there was a sharp drop in power, and then a sharp increase in power, which got out of control and led to the explosion and destruction of reactor 4. The first question that arises in this regard is what kind of experiment it was and why it was carried out?

Experiment with the 4th reactor of the Chernobyl nuclear power plant

On April 25, 1986, maintenance work was carried out at the Chernobyl nuclear power plant, during which the turbogenerator was tested. The essence of the test is whether the turbogenerator will be able to supply energy within 45-50 seconds during an accident in order to provide the emergency systems with the necessary energy.

The very essence of the experiment was to ensure continued safety of use. There is nothing special about this, since experiments are always carried out at any enterprise. Another thing is that any experiments at objects of such importance must be carried out under strict control and with full compliance with the regulations. In this case this was not ensured. This is the reason for the Chernobyl accident.

Everything was quiet, everything was going as usual. Then I heard a conversation, turned around - Toptunov was saying something to Akimov. I didn’t hear what Toptunov said. Akimov told him - shut down the reactor. But, in my opinion, Toptunov told him that the reactor had reached normal levels. There is nothing unusual or dangerous in this. Akimov repeated to him - shut down the reactor. I converted the frequency of 35 Hz into rpm in my head. After that there was the first blow. Following him was a second, stronger one. It was long, or it was two blows merged into one.

Dyatlov – Deputy Chief Engineer of the Chernobyl Nuclear Power Plant. From the interrogation records.

Causes of the accident

The Chernobyl accident today has acquired a huge number of versions. I will not consider versions that are not supported by anything other than the imagination of the authors, and will focus on the reports of the commissions that investigated the disaster. There were 2 such commissions in total: 1986, 1991. The commissions' conclusions contradicted each other.

Commission 1986

In August 1986, a commission was created to study the issues of the Chernobyl disaster. This commission was supposed to establish the reasons why the accident happened. The main conclusion of this commission is personnel are to blame for the Chernobyl accident, who made several gross mistakes at once, which led first to an accident, and then to a catastrophe.

The main mistakes of personnel are as follows:

• Disabling reactor safety equipment. The work regulations prohibited any disabling of protective equipment.
• Removal of 204 out of 211 rods from the work area. The regulations stated that if there are less than 15 rods left, the reactor should be shut down immediately.

The staff mistakes turned out to be gross and inexplicable. They turned off the protection and violated all the main points of the Regulations (instructions).

1991 Commission

In 1991, Gosatomnadzor created a new group to study the accident. To understand the essence of the work of this group, you need to know its composition. The group included almost all the personnel of the nuclear power plant. The conclusion from the work of this group was the following: the designers are to blame for the disaster, since The 4th reactor had design flaws.

The event after which the explosion was inevitable was pressing button A3-5 (emergency button), after which all the rods jammed.

Elimination of consequences

4 minutes after the explosion, the local fire brigade, led by Lieutenant Pravik, began to extinguish the fire on the reactor roof. Additional fire brigades from the region and from Kyiv were called. By 4 o'clock in the morning the fire was localized.

It is noteworthy that until 03:30 on April 26 high level No one knew about radiation. The reason was that there were 2 devices operating at 1000 roentgens per hour. One was out of order, and the second was inaccessible due to the explosion. By the end of April 26, iodine prophylaxis began in the city of Pripyat. On April 27, it was decided to evacuate the residents of the city of Pripyat. In total, about 50 thousand people were evacuated. Of course, no one told them the reasons. They only said that it was for 2-3 days, so you didn’t need to take anything with you.

At the beginning of May, the evacuation of residents in nearby regions began. On May 2, everyone within a 10 km radius was evacuated. On May 4-7, residents were liquidated in an area with a radius of 30 km. This created an exclusion zone. By July 25, this area was completely fenced off and closed to everyone. The perimeter of the zone is 196 km.

On November 14, the construction of the Sracophagus was completed. This is 100 thousand cubic meters of concrete that forever buried the 4th reactor of the Chernobyl nuclear power plant.

Evacuation of the city of Pripyat

The most important question is why the evacuation began 1.5 days after the Chernobyl accident, and not earlier? The fact is that the leadership of the USSR was not prepared in an emergency situation. But the main complaint here is not that people were evacuated only on the evening of April 27, but that on the morning of April 26, when it was known about the high level of radiation, no one warned the city population about this. In fact, June 26, 1986 was an ordinary day for the city of Pripyat, and on April 27 an emergency evacuation began.

610 buses and 240 trucks were sent from Kyiv. Another 522 buses were sent by the Kyiv region. The evacuation of the city, with a population of about 50 thousand people, took place in just 3 hours: from 15:00 to 18:00. At the same time, residents experienced a peak in radiation.

Who participated in the liquidation

Elimination of the consequences of the accident at the Chernobyl nuclear power plant is an important issue, since these events involved more than 0.5 million people who worked in very hazardous conditions. In total, in 1986-1987, 240 thousand people were involved in eliminating the accident. Taking into account subsequent years - 600 thousand. For liquidation the following were used:

• Specialists. First of all, specialists in the field of physics and damage control.
• Staff. These people were used to work on the site because they knew its structure very well.
• Military personnel. Regular units were deployed most widely, and it was the military personnel who bore the brunt (including exposure to radiation) and the main burden.
• Mobilized staff. Just a few days after the Chernobyl accident, mobilization was carried out and the civilian population took part in eliminating the consequences.

The liquidators worked in a circular pattern. As soon as people reached the maximum permissible level of radiation, the group was expelled from Chernobyl, and a a new group. And so on until the consequences were localized. Today it is said that the limit value of human radiation was set at 500 mSv, and the average radiation dose was 100 mSv.

Liquidators of the consequences of the Chernobyl accident

Group	Number		Average radiation dose in mSv
	1986	1987	1986	1987
Chernobyl nuclear power plant personnel	2358	4498	87	15
Builders of the "Shelter"	21500	5376	82	25
Mobilization personnel	31021	32518	6,5	27
Military personnel	61762	63751	110	63

This is the data that statistics provide today, but it is important to note that these are average figures! They cannot reflect the true picture of the case, since this requires data on each person individually. For example, 1 person worked on the liquidation without sparing himself and received a dose of 500 mSv, and another sat at the headquarters and received a dose of 5 mSv - their average value will be 252.5, but in reality the picture is different...

Consequences for people

One of the most terrible stories of the Chernobyl disaster is the consequences for human health. Today it is said that 2 people died in the explosion at the Chernobyl nuclear power plant, 134 people were diagnosed with radiation sickness, and 170 liquidators were diagnosed with leukemia or blood cancer. Among liquidators, compared to other people, the following diseases are more often registered:

• Endocrine system - 4 times
• Cardiovascular system – 3.5 times
• Psychiatric disorders and illnesses nervous system– 2 times.
• Diseases of the musculoskeletal system – 2 times.

If you think about these numbers, it becomes clear that almost every person who took part in the liquidation of the consequences of the accident at the Chernobyl nuclear power plant suffers from one disease or another. People who did not take part in the liquidation also suffered. For example, from 1992 to 2000, 4 thousand cases of thyroid cancer were detected in Russia, Belarus and Ukraine. It is believed that 99% of these cases are related specifically to the accident at the Chernobyl nuclear power plant.

Which countries suffered the most?

The Chernobyl accident is a disaster for the whole of Europe. To demonstrate this, it is sufficient to provide the following table.

Radiation in cities after the Chernobyl accident

City	Irradiation power in microR/h	date
Pripyat	1 370 000	April 28
	2 200	April 30
Novozybkov	6 200	April 29
Gomel	800	April 27
Minsk	60	April 28
Salzburg (Austria)	1 400	May 2
Tavastehaus "Finland"	1 400	April 29
Munich, Germany)	2 500	April 30

If we imagine that the total damage from the Chernobyl disaster is 100%, then the distribution of radioactivity was approximately as follows: Russia - 30%, Belarus - 23%, Ukraine - 19%, Finland - 5%, Sweden - 4.5%, Norway - 3.1%, Austria – 2.5%.

Object "Shelter" and exclusion zone

One of the first decisions after the Chernobyl accident was the creation of an exclusion zone. Initially, the city of Pripyat was evacuated. Then, on May 2, residents were evacuated 10 kilometers away, and on May 7, 30 kilometers away. This constituted the exclusion zone. This is an area that was accessed only by pass and was exposed to the maximum amount of radiation. Therefore, everything that was possible was demolished and buried there, including civilian buildings and residential buildings.

The Shelter object is a program for isolating the 4th nuclear reactor in a concrete structure. Any objects that were in one way or another connected with the functioning of the Chernobyl Nuclear Power Plant and were contaminated were placed in the area of ​​the 4th reactor, over which they began to build a concrete sarcophagus. These works were completed on November 14, 1986. The Shelter object is isolated for 100 years.

Trial of the culprits

On July 7, 1987, in the city of Chernobyl, a trial began of Chernobyl employees accused under Article 220, paragraph 2 of the Criminal Code of the Ukrainian SSR (violation of safety regulations, which resulted in human casualties and other serious consequences) and under Articles 165 and 167 of the Criminal Code of the Ukrainian SSR (abuse of official position and irresponsibility in the performance of official duties).

Defendants:

• Bryukhanov V.P. - Director of the Chernobyl Nuclear Power Plant. 52 years old.
• Fomin N.M. - Chief Engineer. 50 years.
• Dyatlov A.S. - Deputy Chief Engineer. 56 years old.
• Kovalenko A, P. – head of the reactor of workshop No. 2. 45 years.
• Laushkin Yu.A. - Inspector of GAEN at the Chernobyl Nuclear Power Plant. 51 years old
• Rogozhkin B.V. – shift supervisor at the Chernobyl nuclear power plant. 53 years old.

The trial lasted 18 days, and the verdict was pronounced on July 29, 1987. According to the court verdict, all the accused were found guilty and sentenced to a term of 5 to 10 years. I would like to quote the last words of the accused, as they are indicative.

Accused for the accident at the Chernbyl nuclear power plant

Defendant	Guilty plea
Bryukhanov	I see that the staff made mistakes. The staff lost their sense of danger, largely due to a lack of instructions. But an accident is a probability of circumstances, the probability of which is negligible.
Fomin	I admit my guilt and repent. Why was I unable to ensure the safety of the Chernobyl nuclear power plant? I am an electrician by training! I didn't have enough time to study physics.
Dyatlov	My violations were unintentional. If I were a video danger, I would stop the reactor.
Rogozhkin	I don’t see evidence of my guilt, because the accusations are nonsense, I don’t even understand why they were brought against me.
Kovalenko	I believe that if there were violations on my part, then they relate to administrative, but not criminal liability. I couldn’t even think that the staff would violate the Regulations.
Laushkin	I didn't do what I'm accused of. I'm completely innocent.

At the same time, the following lost their positions: the chairman of Gosatomenergonadzor (Kulov E.V.), his deputy for energy (Shasharin) and the deputy minister of medium-sized engineering (Mashkov). In the future, the issue of responsibility and transfer of the case to court against the official was to be decided by the Party, but there was no trial of them.

Literature:

• Transcript of court hearings. Chernobyl, 1987, Karpan N.V.
• 3. Extract from criminal case No. 19 -73 (vol. 50, pp. 352-360).
• Chernobyl radiation in questions and answers. Moscow, 2005.

Over the past two centuries, humanity has experienced an incredible technological boom. We discovered electricity, built flying machines, mastered low-Earth orbit and we’re already climbing into the backyards solar system. Opening chemical element called uranium showed us new possibilities for obtaining large amounts of energy without the need to consume millions of tons of fossil fuel.

The problem of our time is that the more complex the technologies we use, the more serious and destructive the disasters associated with them. First of all, this applies to the “peaceful atom”. We have learned to create complex nuclear reactors that power cities, submarines, aircraft carriers, and in plans even spaceships. But not a single modern reactor is 100% safe for our planet, and the consequences of errors in its operation can be catastrophic. Isn't it too early for humanity to take up the development of atomic energy?

We have already paid more than once for our awkward steps in conquering the peaceful atom. Nature will take centuries to correct the consequences of these disasters, because human capabilities are very limited.

The Chernobyl accident. April 26, 1986

One of the largest man-made disasters of our time, which caused irreparable harm to our planet. The consequences of the accident were felt even on the other side of the globe.

On April 26, 1986, as a result of a personnel error during the operation of the reactor, an explosion occurred in the 4th power unit of the station, which forever changed the history of mankind. The explosion was so powerful that multi-ton roof structures were thrown several tens of meters into the air.

However, it was not the explosion itself that was dangerous, but the fact that it and the resulting fire were carried from the depths of the reactor to the surface. A huge cloud of radioactive isotopes rose into the sky, where it was immediately picked up by air currents that carried it in a European direction. Heavy rainfall began to cover cities where tens of thousands of people lived. The territories of Belarus and Ukraine suffered the most from the explosion.

A volatile mixture of isotopes began to infect unsuspecting residents. Almost all of the iodine-131 that was in the reactor ended up in the cloud due to its volatility. Despite its short half-life (only 8 days), it managed to spread over hundreds of kilometers. People inhaled a suspension with a radioactive isotope, causing irreparable harm to the body.

Along with iodine, other, even more dangerous elements rose into the air, but only volatile iodine and cesium-137 (half-life 30 years) were able to escape in the cloud. The rest, heavier radioactive metals, fell within a radius of hundreds of kilometers from the reactor.

The authorities had to evacuate an entire young city called Pripyat, which at that time was home to about 50 thousand people. Now this city has become a symbol of disaster and an object of pilgrimage for stalkers from all over the world.

Thousands of people and pieces of equipment were sent to eliminate the consequences of the accident. Some of the liquidators died during the work, or died afterwards from the effects of radioactive exposure. Most became disabled.

Despite the fact that almost the entire population of the surrounding areas was evacuated, people still live in the Exclusion Zone. Scientists do not undertake to give accurate forecasts about when the latest evidence of the Chernobyl accident will disappear. According to some estimates, this will take from several hundred to several thousand years.

Accident at Three Mile Island Station. March 20, 1979

Most people, as soon as they hear the expression “nuclear disaster,” immediately think of the Chernobyl nuclear power plant, but in fact there were many more such accidents.

On March 20, 1979, an accident occurred at the Three Mile Island nuclear power plant (Pennsylvania, USA), which could have become another powerful man-made disaster, but it was prevented in time. Before the Chernobyl accident, this incident was considered the largest in the history of nuclear energy.

Due to a coolant leak from the circulation system around the reactor, the cooling of nuclear fuel was completely stopped. The system became so hot that the structure began to melt, metal and nuclear fuel turned into lava. The temperature at the bottom reached 1100°. Hydrogen began to accumulate in the reactor circuits, which the media perceived as an explosion threat, which was not entirely true.

Due to the destruction of the shells of the fuel elements, radioactive ones from nuclear fuel entered the air and began to circulate through the station's ventilation system, after which they entered the atmosphere. However, when compared with the Chernobyl disaster, there were few casualties here. Only noble radioactive gases and a small portion of iodine-131 were released into the air.

Thanks to the coordinated actions of the station personnel, the threat of a reactor explosion was averted by resuming cooling of the melted machine. This accident could have become an analogue of the explosion at the Chernobyl nuclear power plant, but in this case people coped with the disaster.

US authorities decided not to close the power plant. The first power unit is still operating.

Kyshtym accident. September 29, 1957

Another industrial accident involving the release of radioactive substances occurred in 1957 at the Soviet enterprise Mayak near the city of Kyshtym. In fact, the city of Chelyabinsk-40 (now Ozersk) was much closer to the accident site, but then it was strictly classified. This accident is considered the first man-made radiation disaster in the USSR.
Mayak is engaged in the processing of nuclear waste and materials. It is here that weapons-grade plutonium is produced, as well as a host of other radioactive isotopes used in industry. There are also warehouses for storing spent nuclear fuel. The enterprise itself is self-sufficient in electricity from several reactors.

In the fall of 1957, there was an explosion at one of the nuclear waste storage facilities. The reason for this was a failure of the cooling system. The fact is that even spent nuclear fuel continues to generate heat due to the ongoing decay reaction of the elements, so the storage facilities are equipped with their own cooling system that maintains the stability of the sealed containers with nuclear mass.

One of the containers with a high content of radioactive nitrate-acetate salts underwent self-heating. The sensor system could not detect this because it simply rusted due to the negligence of the workers. As a result, a container with a volume of more than 300 cubic meters exploded, which tore off the roof of the storage facility weighing 160 tons and threw it almost 30 meters. The force of the explosion was comparable to the explosion of tens of tons of TNT.

A huge amount of radioactive substances were lifted into the air to a height of up to 2 kilometers. The wind picked up this suspension and began to spread it across the nearby territory in a northeast direction. In just a few hours, radioactive fallout spread over hundreds of kilometers and formed a unique strip 10 km wide. A territory with an area of ​​23 thousand square kilometers, in which almost 270 thousand people lived. Characteristically, the Chelyabinsk-40 facility itself was not damaged due to weather conditions.

Commission for liquidation of consequences emergency situations decided to evict 23 villages, the total population of which was almost 12 thousand people. Their property and livestock were destroyed and buried. The contamination zone itself was called the East Ural radioactive trace.
Since 1968, the East Ural State Reserve has been operating in this territory.

Radioactive contamination in Goiania. September 13, 1987

Undoubtedly, the dangers of nuclear power, where scientists work with large volumes of nuclear fuel and complex devices, cannot be underestimated. But radioactive materials are even more dangerous in the hands of people who do not know what they are dealing with.

In 1987, in the Brazilian city of Goiania, looters managed to steal from an abandoned hospital a part that was part of radiotherapy equipment. Inside the container was the radioactive isotope cesium-137. The thieves didn't figure out what to do with this part, so they decided to just throw it in a landfill.
After some time, an interesting shiny object attracted the attention of the owner of the landfill, Devar Ferreira, who was passing by. The man thought of bringing the curiosity home and showing it to his household, and also called friends and neighbors to admire the unusual cylinder with an interesting powder inside, which glowed with a bluish light (radioluminescence effect).

Extremely improvident people did not even think that such a strange thing could be dangerous. They picked up parts of the part, touched cesium chloride powder and even rubbed it on their skin. They liked the pleasant glow. It got to the point that pieces of radioactive material began to be passed on to each other as gifts. Due to the fact that radiation in such doses does not have an immediate effect on the body, no one suspected anything was wrong, and the powder was distributed among the city residents for two weeks.

As a result of contact with radioactive materials, 4 people died, among whom was Devar Ferreira’s wife, as well as his brother’s 6-year-old daughter. Several dozen more people were undergoing treatment for radiation exposure. Some of them died later. Ferreira himself survived, but all his hair fell out and he also suffered irreversible damage to his internal organs. The man spent the rest of his life blaming himself for what happened. He died of cancer in 1994.

Despite the fact that the disaster was local in nature, the IAEA assigned it danger level 5 on the international scale of nuclear events out of 7 possible.
After this incident, a procedure for the disposal of radioactive materials used in medicine was developed, and control over this procedure was tightened.

Fukushima disaster. March 11, 2011

The explosion at the Fukushima nuclear power plant in Japan on March 11, 2011 was equated on the scale of danger to the Chernobyl disaster. Both accidents received a rating of 7 on the International Nuclear Event Scale.

The Japanese, who once became victims of Hiroshima and Nagasaki, now have another catastrophe on a planetary scale in their history, which, however, unlike its world counterparts, is not a consequence of the human factor and irresponsibility.

The cause of the Fukushima accident was a devastating earthquake with a magnitude of more than 9, which was recognized as the strongest earthquake in the history of Japan. Almost 16 thousand people died as a result of the collapses.

Tremors at a depth of more than 32 km paralyzed the operation of a fifth of all power units in Japan, which were under automatic control and provided for such a situation. But the gigantic tsunami that followed the earthquake completed what had been started. In some places the wave height reached 40 meters.

The earthquake disrupted the operation of several nuclear power plants. For example, the Onagawa Nuclear Power Plant experienced a power unit fire, but the staff managed to correct the situation. At Fukushima-2, the cooling system failed, which was repaired in time. The worst hit was Fukushima-1, which also had a cooling system failure.
Fukushima-1 is one of the largest nuclear power plants on the planet. It consisted of 6 power units, three of which were not in operation at the time of the accident, and three more were turned off automatically due to the earthquake. It would seem that the computers worked reliably and prevented disaster, but even in a stopped state, any reactor needs to be cooled, because the decay reaction continues, generating heat.

The tsunami that hit Japan half an hour after the earthquake knocked out the reactor's emergency cooling power system, causing diesel generator sets to stop working. Suddenly, the plant personnel were faced with the threat of overheating of the reactors, which had to be eliminated as soon as possible. The nuclear power plant personnel made every effort to provide cooling to the hot reactors, but the tragedy could not be avoided.

Hydrogen accumulated in the circuits of the first, second and third reactors created such pressure in the system that the structure could not withstand it and a series of explosions were heard, causing the collapse of the power units. In addition, the 4th power unit caught fire.

Radioactive metals and gases rose into the air, which spread throughout the nearby area and entered the ocean waters. Combustion products from the nuclear fuel storage facility rose to a height of several kilometers, spreading radioactive ash hundreds of kilometers around.

Tens of thousands of people were involved in eliminating the consequences of the Fukushima-1 accident. Urgent solutions were required from scientists on ways to cool the hot reactors, which continued to generate heat and release radioactive substances into the soil under the station.

To cool the reactors, a water supply system was organized, which, as a result of circulation in the system, becomes radioactive. This water accumulates in reservoirs on the territory of the station, and its volumes reach hundreds of thousands of tons. There is almost no space left for such reservoirs. The problem with pumping radioactive water from reactors has not yet been resolved, so there is no guarantee that it will not end up in the oceans or the soil under the station as a result of a new earthquake.

There have already been precedents for the leakage of hundreds of tons of radioactive water. For example, in August 2013 (300 tons leakage) and February 2014 (100 tons leakage). The level of radiation in groundwater is constantly increasing, and people cannot influence it in any way.

At the moment, have been developed special systems for the decontamination of contaminated water, which make it possible to neutralize water from reservoirs and reuse it to cool reactors, but the efficiency of such systems is extremely low, and the technology itself is not yet sufficiently developed.

Scientists have developed a plan that involves extracting molten nuclear fuel from reactors in power units. The problem is that humanity currently does not have the technology to carry out such an operation.

The preliminary date for removing molten reactor fuel from the system circuits is 2020.
After the disaster on nuclear power plant More than 120 thousand residents of nearby areas were evacuated from Fukushima-1.

Radioactive contamination in Kramatorsk. 1980-1989

Another example of human negligence in handling radioactive elements, which led to the death of innocent people.

Radiation contamination occurred in one of the houses in the city of Kramatorsk, Ukraine, but the event has its own background.

At the end of the 70s, in one of the mining quarries of the Donetsk region, workers managed to lose a capsule with a radioactive substance (cesium-137), which was used in a special device for measuring the level of contents in closed vessels. The loss of the capsule caused panic among the management, because crushed stone from this quarry was delivered, among other things. and to Moscow. By personal order of Brezhnev, the extraction of crushed stone was stopped, but it was too late.

In 1980, in the city of Kramatorsk, the construction department commissioned a panel residential building. Unfortunately, a capsule with a radioactive substance fell along with rubble into one of the walls of the house.

After residents moved into the house, people began to die in one of the apartments. Just a year after moving in, an 18-year-old girl died. A year later, her mother and brother died. The apartment became the property of new residents, whose son soon died. The doctors diagnosed all the dead with the same diagnosis - leukemia, but this coincidence did not alarm the doctors at all, who blamed everything on bad heredity.

Only the persistence of the father of the dead boy made it possible to determine the cause. After measurements background radiation in the apartment it became clear that it was going off scale. After a short search, the section of the wall where the background came from was identified. After delivering a piece of the wall to the Kiev Institute of Nuclear Research, scientists removed from there the ill-fated capsule, the dimensions of which were only 8 by 4 millimeters, but the radiation from it was 200 milliroentgen per hour.

The result of local infection over 9 years was the death of 4 children, 2 adults, as well as disability of 17 people.