NPP - nuclear equipment for generating electricity, which operates under specified conditions and mode. It is a nuclear reactor connected to various systems necessary for its full and safe operation. Accidents at nuclear power plants are large-scale man-made disasters. Despite the fact that they generate electricity in an environmentally friendly way, the consequences of failures are felt all over the world.

Why are nuclear power plants dangerous?

World map of the location of nuclear power plants

An accident at a power plant occurs due to errors in the maintenance of the system, wear and tear of equipment, or due to natural disasters. Failures due to design errors occur in the early stages of a nuclear power plant start-up and are much less common. The most common human factor in the occurrence of emergencies. Equipment malfunctions are accompanied by the release of radioactive particles into the environment.

The emission power and the degree of pollution of the surrounding area depend on the type of breakdown and the time it takes to fix the problem. The most dangerous situations are those associated with overheating of reactors due to a malfunction of the cooling system and depressurization of the fuel rod casing. In this case, radioactive vapors are released through the ventilation pipe into the external environment. Accidents at power plants in Russia do not go beyond hazard class 3 and are minor incidents.

Radiation disasters in Russia

The largest accident occurred in the Chelyabinsk region in 1948 at the Mayak plant in the process of commissioning a plutonium-fueled nuclear reactor to the power specified by the project. Due to poor cooling of the reactor, several blocks of uranium combined with graphite located around them. The liquidation of the incident lasted 9 days. Later, in 1949, dangerous liquid contents were dumped into the Techa River. The population of 41 points located nearby was affected. In 1957, a man-made disaster called "Kushtymskaya" occurred at the same plant.

UKRAINE. Chernobyl exclusion zone.

In 1970, in Nizhny Novgorod, during the production of a nuclear vessel at the Krasnoye Sormovo plant, a prohibited launch of a nuclear reactor took place, which began to operate at exorbitant power. A fifteen-second failure caused contamination of the closed area of ​​the workshop, the radioactive contents did not get outside the territory of the plant. The liquidation of the consequences lasted 4 months, most of the liquidators died due to an excess of exposure.

Another man-made accident was hidden from the public. In 1967, the largest disaster ALVZ-67 occurred, as a result of which the population of the Tyumen and Sverdlovsk regions suffered. The details were hidden, and little is known about what happened to date. Pollution of the territory occurred unevenly, foci appeared in which the coverage density exceeded 50 curies per 100 km. Accidents at power plants in Russia are local in nature and do not pose a danger to the population, they include:

• a fire at the Beloyarsk NPP in 1978 due to the fall of the ceiling on the oil tank of the turbine generator, in 1992 due to the negligence of employees when pumping radioactive components for subsequent specialized cleaning;
• pipeline rupture in 1984 at the Balakovo NPP;
• when the power supply sources of the Kola NPP are de-energized due to a hurricane;
• failures in the operation of the reactor in 1987 at the Leningrad NPP with the release of radiation outside the plant, minor failures in 2004 and 2015. without global consequences for the environment.

In 1986, an accident occurred at a world-scale power plant in Ukraine. Part of the active reaction zone was destroyed, as a result of a global catastrophe, the Western part of Ukraine, 19 western regions of Russia and Belarus were contaminated with radioactive substances, and the 30-kilometer zone became uninhabitable. The active content releases lasted almost two weeks. Explosions at nuclear power plants in Russia have not been recorded for the entire period of the existence of nuclear energy.

The risk of breakdowns at nuclear power plants is calculated according to the IAEA International Scale. Conventionally, man-made disasters can be divided into two levels of danger:

• lower level (grades 1-3) - minor failures that are classified as incidents;
• medium level (class 4-7) - significant malfunctions, which are called accidents.

Extensive consequences cause incidents of hazard class 5-7. Breakdowns below the third class are most often dangerous only for plant personnel due to contamination of the internal premises and exposure of employees. The probability of a global catastrophe is 1 in 1-10 thousand years. The most dangerous accidents at nuclear power plants are classified as class 5-7, they cause negative consequences for the environment and the population. Modern nuclear power plants have four degrees of protection:

• a fuel matrix that does not allow decay products to leave the radioactive shell;
• a radiator shell that protects the ingress of hazardous substances into the circulation circuit;
• the circulation circuit does not allow the radioactive contents to leak out under the containment;
• a complex of shells called a containment.

The outer dome protects the room from the release of radiation outside the plant, this dome can withstand a shock wave of 30 kPa, so an explosion of a nuclear power plant with global emissions is unlikely. Which nuclear power plants are most dangerous for explosions? Incidents are considered the most dangerous when ionizing radiation is emitted outside the safety system of the reactor in an amount exceeding the parameters provided for by the design documentation. They are called:

• the lack of control of the nuclear reaction within the unit and the inability to control it;
• failure of the TEL cooling system;
• the emergence of a critical mass due to reloading, transportation and storage of spent components.

On March 11, 2011, Japan was hit by an earthquake measuring 9.0 on the Richter scale, resulting in a devastating tsunami. In one of the most affected regions was the Fukushima Daiichi nuclear power plant, where, 2 days after the earthquake, an explosion occurred. This accident was called the largest since the explosion at the Chernobyl nuclear power plant in 1986.

In this issue, we take a look back at 11 of the biggest nuclear accidents and disasters in recent history.

(Total 11 photos)

1. Chernobyl, Ukraine (1986)

On April 26, 1986, the reactor at the Chernobyl nuclear power plant in Ukraine exploded, resulting in the worst radiation pollution in history. A radiation cloud hit the atmosphere 400 times more than during the bombing of Hiroshima. The cloud passed over the western part of the Soviet Union and also affected Eastern, Northern and Western Europe.
Fifty people died in the reactor explosion, but the number of people who got in the way of the radioactive cloud remains unknown. The report of the World Atomic Association (http://world-nuclear.org/info/chernobyl/inf07.html) mentions more than a million people who may have been exposed to radiation. However, it is unlikely that it will ever be possible to establish the full scale of the catastrophe.
Photo: Laski Diffusion | Getty Images

2. Tokaimura, Japan (1999)

Until March 2011, the most serious incident in Japanese history was the Tokaimura uranium accident on September 30, 1999. Three workers tried to mix nitric acid and uranium to produce uranyl nitrate. However, unknowingly, the workers took seven times the allowed amount of uranium, and the reactor did not keep the solution from reaching critical mass.
Three workers received strong gamma and neutron radiation, from which, subsequently, two of them died. 70 other workers also received high doses of radiation. After investigating the incident, the IAEA reported that "human error and a serious disregard for safety principles" were the cause of the incident.
Photo: AP

3. Accident at the nuclear power plant Three Mile Island, Pennsylvania

On March 28, 1979, the largest accident in US history occurred at the Three Mile Island nuclear power plant in Pennsylvania. The cooling system did not work, which caused a partial meltdown of the nuclear fuel elements of the reactor, but a complete meltdown was avoided, and the disaster did not occur. However, despite the favorable outcome and the fact that more than three decades have passed, the incident still remains in the memory of those who were present.

The consequences of this incident for the American nuclear industry were colossal. The accident caused many Americans to reconsider their views on the use of atomic energy, and the construction of new reactors, which has been constantly increasing since the 1960s, has slowed significantly. In just 4 years, more than 50 plans for the construction of nuclear power plants were canceled, and from 1980 to 1998, many ongoing projects were canceled.

4. Goiania, Brazil (1987)

One of the worst cases of radiation contamination of the area happened in the city of Goiania in Brazil. The Institute of Radiotherapy moved, leaving the radiotherapy unit in the old building, which still contained cesium chloride.

On September 13, 1987, two looters found the unit, removed it from the hospital grounds, and sold it to a landfill. The landfill owner invited relatives and friends to look at the glowing blue substance. All of them then dispersed around the city and began to infect their friends and relatives with radiation.

The total number of infected people was 245, and four of them died. According to Eliana Amaral from the IAEA, this tragedy had a positive consequence: “Before the incident in 1987, no one knew that radiation sources had to be monitored from the moment they were created and then until they were disposed of, and also to prevent any contact with the civilian population. This case contributed to the emergence of such considerations.

5. K-19, Atlantic Ocean (1961)

On July 4, 1961, the Soviet submarine K-19 was in the North Atlantic Ocean when a reactor leak was noticed on it. There was no reactor cooling system and, having no other options, the team members went into the reactor compartment and repaired the leak with their own hands, exposing themselves to doses of radiation incompatible with life. All eight crew members who fixed the reactor leak died within 3 weeks of the accident.

The rest of the crew, the boat itself and ballistic missiles on it were also subjected to radiation contamination. When K-19 rendezvoused with the boat that received their distress call, it was towed back to base. Then, during the repair, which lasted 2 years, the surrounding area was contaminated, and the workers of the dock were also exposed to radiation. In the next few years, another 20 crew members died from radiation sickness.

6. Kyshtym, Russia (1957)

Tanks for radioactive waste were stored at the Mayak chemical plant near the city of Kyshtym, and as a result of a malfunction in the cooling system, an explosion occurred, due to which about 500 km of the surrounding area were exposed to radiation contamination.

Initially, the Soviet government did not disclose the details of the incident, but a week later they were left with no choice. 10,000 people were evacuated from areas where symptoms of radiation sickness had already begun to appear. Although the USSR refused to divulge details, the journal Radiation and Environmental Biophysics estimates that at least 200 people died from radiation. The Soviet government finally declassified all information about the accident in 1990.

7. Windscale, England (1957)

On October 10, 1957, Windscale became the site of the worst nuclear accident in British history and the worst in the world until the Three Mile Island accident 22 years later. The Windscale complex was built to produce plutonium, but when the US built the tritium atomic bomb, the complex was converted to produce tritium for Britain. However, this required the reactor to operate at higher temperatures than those for which it was originally designed. The result was a fire.

At first, the operators were reluctant to extinguish the reactor with water because of the threat of an explosion, but eventually gave up and flooded it. The fire was extinguished, but a huge amount of contaminated water got into the environment. Studies in 2007 showed that this release led to more than 200 cases of cancer in the surrounding area.

Photo: George Freston | Hulton Archive | Getty Images

8. SL-1, Idaho (1961)

Stationary Low Power Reactor Number 1, or SL-1, was located in the desert 65 km from the town of Idaho Falls, Idaho. On January 3, 1961, the reactor exploded, killing 3 workers and causing the fuel elements to melt. The reason was an incorrectly removed reactor power control rod, but even 2 years of investigation did not give an idea about the actions of the personnel before the accident.

Although the reactor released radioactive materials into the atmosphere, they were few and its remote location minimized the damage to the population. Yet, this incident is notable for being the only fatal nuclear reactor accident in US history. Also, the incident led to an improvement in the design of nuclear reactors, and now one rod for regulating the power of the reactor will not be able to cause such damage.
Photo: United States Department of Energy

9. North Star Bay, Greenland (1968)

On January 21, 1968, a US Air Force B-52 bomber flew as part of Operation Chrome Dome, a Cold War-era operation in which US nuclear-capable bombers were in the air all the time, ready to strike targets in the Soviet Union. A bomber carrying four hydrogen bombs caught fire. The next emergency landing could have been made at Thule Air Base in Greenland, but there was no time to land, and the team left the burning plane.

When the bomber fell, the nuclear warheads detonated, which caused the contamination of the area. The March 2009 issue of Time magazine said it was one of the worst nuclear disasters of all time. The incident prompted the immediate shutdown of the Chrome Dome program and the development of more stable explosives.
Photo: U.S. air force

10 Jaslovske Bohunice, Czechoslovakia (1977)

The nuclear power plant in Bohunice was the very first in Czechoslovakia. The reactor was an experimental design to run on uranium mined in Czechoslovakia. Despite this, the first of its kind complex had many accidents, and it had to close more than 30 times.

Two workers died in 1976, but the worst accident occurred on February 22, 1977, when one of the workers, during a routine fuel change, incorrectly removed the reactor power control rod. This simple mistake caused a massive reactor leak and, as a result, the incident earned a level 4 on the International Nuclear Event Scale from 1 to 7.

The Soviet government covered up the incident, so no casualties are known. However, in 1979 the government of socialist Czechoslovakia decommissioned the station. It is expected to be dismantled by 2033.
Photo: www.chv-praha.cz

11. Yucca Flat, Nevada (1970)

Yucca Flat is an hour from Las Vegas and is one of Nevada's nuclear test sites. On December 18, 1970, during the detonation of a 10-kiloton atomic bomb buried 275 meters underground, the plate holding the explosion from the surface cracked, and a column of radioactive fallout rose into the air, as a result of which 86 people who took part in the tests were irradiated.

In addition to the fact that the radiation fallout fell in the district, they were also carried to the north of Nevada, to the states of Idaho and California, as well as to the eastern parts of the states of Oregon and Washington. Also, the precipitation appears to have been carried to the Atlantic Ocean, Canada, and the Gulf of Mexico. In 1974, two specialists who were present at the explosion died of leukemia.

Photo: National Nuclear Security Administration / Nevada Site Office

Characteristics of accidents at nuclear power plants

Radiation accident - loss of control of a source of ionizing radiation caused by a malfunction, damage to equipment, improper actions of employees (personnel), natural phenomena or other reasons that could lead or have led to exposure of people or radioactive contamination of the environment in excess of established standards.

The main sources of environmental pollution with radioactive substances include manufacturing enterprises that extract and process raw materials containing radioactive substances, nuclear facilities (NW), radiochemical plants, research institutes and other facilities.

The most dangerous sources of ionizing radiation and radioactive contamination of the environment are accidents at nuclear facilities. Radiation accidents at nuclear facilities are understood as a violation of their safe operation, in which radioactive products and (or) ionizing radiation escaped beyond the boundaries provided for by the project for normal operation in quantities exceeding the established values. Radiation accidents are characterized by the initiating event, the nature of the course and radiation consequences.

In 1988, the International Atomic Energy Agency (IAEA) developed the International Nuclear Event Scale (INES, abbr. International Nuclear Event Scale). Since 1990, this scale has been used for the purpose of uniform assessment of emergency cases related to the civil nuclear industry.

The scale is applicable to any event related to the transport, storage and use of radioactive materials and radiation sources and covers a wide range of practices, including radiography, the use of radiation sources in hospitals, in any civil nuclear installations, etc. It also includes the loss and theft of radiation sources and the discovery of orphan sources.

According to the INES scale, nuclear and radiological accidents and incidents are classified into 8 levels (Appendix 1):

Level 7. Major accident

Level 6

Level 5. Accident with wide consequences

Level 4. Accident with local consequences

Level 3. Serious incident

Level 2 Incident

Level 1. Abnormal situation

Level 0. Event below the scale.

Chronology of accidents and disasters at nuclear power plants

A complete chronology of events is described in an environmental blog post dated April 17, 2011. The world's first serious accident occurred on December 12, 1952 in Canada, Ontario, at the Chalk River nuclear power plant "NRX". A technical error of the personnel led to overheating and partial melting of the core. Thousands of curies of fission products were released into the environment, and about 3,800 cubic meters of radioactively contaminated water was dumped directly onto the ground, into shallow trenches near the Ottawa River.

Almost 14 years later, on October 5, 1966 in the United States at the Enrico Fermi nuclear power plant, an accident occurred in the cooling system of an experimental nuclear reactor, which caused a partial melting of the core. The staff managed to manually stop it. It took a year and a half to restart the reactor at full capacity.

Three years later, in France, on October 17, 1969, at the Saint Laurent nuclear power plant, when reloading fuel at an operating reactor, the operator mistakenly loaded into the fuel channel not a fuel assembly, but a device for controlling the flow of gases. As a result of the melting of five fuel elements, about 50 kilograms of molten fuel fell into the reactor vessel. There was a release of radioactive products into the environment. The reactor was shut down for one year.

On March 20, 1975, a fire broke out at the Brown Ferry nuclear power plant in the United States, which lasted 7 hours and caused direct material damage of 10 million dollars. Two reactor blocks were disabled for more than a year, which caused an additional $10 million in losses. The cause of the fire was the non-compliance with safety measures during the work on sealing the cable glands that passed through the wall of the reactor hall. The verification of this work was carried out in the most primitive way; by the deflection of the flame of a burning stearin candle. As a result, the insulation materials of the cable holes ignited, and then the fire penetrated into the reactor room. It took a lot of effort to bring the reactor to a trouble-free mode and put out the fire.

On January 5, 1976, an refueling accident occurred at the Bohunice nuclear power plant in Czechoslovakia. With an extensive leak of "hot" radioactive gas, two station workers died. The emergency exit through which they could leave the scene of the emergency was blocked (to "prevent frequent cases of theft"). The population was not warned about the accidental release of radioactivity.

The largest accident in the history of US nuclear power occurred on March 28, 1979 at the Three Mile Island Nuclear Power Plant. As a result of a series of equipment failures and operator errors, 53 percent of the reactor core melted at the second power unit of the nuclear power plant. What happened was like a domino effect. First, the water pump failed. Then, due to the interrupted supply of cooling water, the uranium fuel melted and went beyond the shells of the fuel assemblies. The resulting radioactive mass destroyed most of the core and almost burned through the reactor vessel. If this happened, the consequences would be catastrophic. However, the station staff managed to restore the water supply and reduce the temperature. During the accident, about 70 percent of the radioactive fission products accumulated in the core passed into the primary coolant. The exposure dose rate inside the vessel, in which the reactor and the primary circuit system were enclosed, reached 80 R/h. There was a release into the atmosphere of an inert radioactive gas - xenon, as well as iodine. In addition, 185 cubic meters of weakly radioactive water were dumped into the Saskugana River. 200 thousand people were evacuated from the area exposed to radiation. The residents of Dauphin County, who lived near the nuclear power plant, suffered the most. Serious negative consequences had a two-day delay in the decision to evacuate children and pregnant women from the 10-kilometer zone around the nuclear power plant. Work on cleaning up the second power unit, almost completely destroyed as a result of the accident, took as much as 12 years and cost $ 1 billion, which actually bankrupted the owner company.

On March 8, 1981, about 4,000 gallons of highly radioactive water leaked at the Tsugura Nuclear Power Plant in Japan through a crack in the bottom of the building where spent fuel assemblies were stored. 56 workers were subjected to radioactive exposure. A total of four such leaks occurred between January 10 and March 8, 1981. 278 NPP workers received increased exposure during emergency recovery operations.

On December 9, 1986, as a result of a break in the secondary pipeline at the Surry nuclear power plant in the United States, 120 cubic meters of superheated radioactive water and steam were released. Eight nuclear power plant workers fell under a boiling stream. Four of them died from their burns. The cause of the accident was the corrosion wear of the pipeline, which led to a decrease in the thickness of the pipe walls (from 12 to 1.6 mm).

The largest accident in the history of the Spanish nuclear industry (an event of the third level on the INES scale) occurred at the Vandellos nuclear power plant on October 19, 1989. Fire at the first power unit of the nuclear power plant. Due to the sudden stop of one of the turbines, overheating and decomposition of the lubricating oil occurred. The resulting hydrogen exploded, which caused the turbine to ignite. Since the automatic fire extinguishing system did not work at the station, the fire departments of neighboring cities were called, including those located at a distance of up to 100 kilometers from the nuclear power plant. The fight with the fire lasted more than 4 hours. During this time, the turbine power supply and reactor cooling systems were seriously damaged. The firemen who worked at the station risked their lives. They did not know the location and functions of its facilities, they were not familiar with the emergency plan at the nuclear power plant. They used water instead of foam to extinguish electrical systems, which could lead to electric shock. In addition, people were not warned about the risk of working in areas with high levels of radiation. So, three years after Chernobyl, firefighters, already in another country, became hostages of a dangerous situation at a nuclear power plant. Luckily, none of them were badly hurt this time.

In Japan, on February 9, 1991, an accident occurred at the Mihama nuclear power plant, 320 kilometers northwest of Tokyo. Due to a pipe rupture, 55 tons of radioactive water leaked from the cooling system of the reactor of the second power unit. There was no radioactive contamination of personnel and the area, but the incident was considered at that time the most serious accident at Japanese nuclear power plants.

An accident of the third level according to the INES scale was recorded at the Khmelnitsky NPP in Ukraine on July 25, 1996. There was a release of radioactive products into the premises of the station. One person died.

During scheduled maintenance work on April 10, 2003, at the second power unit of the Paks NPP (Hungary), inert radioactive gases and radioactive iodine were released into the atmosphere. The reason is damage to fuel assemblies during chemical cleaning of their surface in a special container. An accident of the third level according to the INES scale.

On July 4, 2003, an explosion occurred at the radioactive waste processing plant of the Fugen nuclear complex, 350 kilometers west of the city of Tokyo, which caused a fire. The 165 MW experimental nuclear reactor, shut down in March 2003, was not affected by this incident.

Accident at the Mihama nuclear power plant on August 9, 2004. From the burst pipe of the second circuit of the cooling system of the third power unit, a jet of steam with a temperature of 270 ° escaped and scalded the workers who were in the turbine hall. Four people died and 18 were seriously injured.

On August 25, 2004, a large leak of radioactive water occurred from the cooling system of the reactor of the second power unit of the Vandellos NPP (Spain). According to the Spanish Council for Radiation Safety, this is the most serious accident at this nuclear power plant since a fire in 1989.

On March 11, 2011, Japan was hit by the most powerful earthquake in the history of the country. As a result, a turbine was destroyed at the Onagawa NPP, a fire broke out, which was quickly extinguished. The situation at the Fukushima-1 NPP was very serious - as a result of the shutdown of the cooling system, nuclear fuel melted in the reactor of block No. 1, a radiation leak was recorded outside the block, and evacuation was carried out in a 10-kilometer zone around the nuclear power plant. The next day, March 12, the media reported an explosion at a nuclear power plant.

On March 19, 2012, Canadian authorities reported a radioactive water leak into Lake Ontario from a nuclear power plant owned by Ontario Power. According to MIGnews, the nuclear power plant is located in the city of Pickering, 35 km from Toronto. The company said in a statement that 73,000 liters of radioactive water entered the lake. This fact was confirmed by representatives of the Canadian Commission on Nuclear Safety.

On October 26, 2012, a radiation leak occurred at the French nuclear power plant Flamanville, located in the northwestern department of the Manche, causing the first reactor to go into a cold shutdown. Over the past year, this is not the first case of accidents at French nuclear power plants, which makes opponents of this type of energy increasingly demand the abandonment of nuclear energy.

Over the past two centuries, mankind has experienced an incredible technological boom. We have discovered electricity, built flying machines, mastered low-Earth orbit and are already climbing into the outskirts of the solar system. The discovery of a chemical element called uranium showed us new possibilities in 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 refers to the “peaceful atom”. We have learned how to create complex nuclear reactors that power cities, submarines, aircraft carriers, and even spaceships are planned. But not a single most 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 clumsy steps in conquering the peaceful atom. Nature will correct the consequences of these catastrophes for centuries, 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 into the air for several tens of meters.

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. Phonic precipitation began to cover the cities in which tens of thousands of people lived. The territories of Belarus and Ukraine suffered the most from the explosion.

The volatile mixture of isotopes began to hit unsuspecting residents. Almost all of the iodine-131 that was in the reactor ended up in a cloud due to its volatility. Despite the short half-life (only 8 days), it managed to spread hundreds of kilometers. People inhaled a suspension with a radioactive isotope, receiving 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) could escape in the cloud. The rest, heavier radioactive metals, fell out within a radius of hundreds of kilometers from the reactor.

The authorities had to evacuate a whole 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 thrown to eliminate the consequences of the accident. Some of the liquidators died during the work, or died later from the effects of radioactive exposure. Most became disabled.

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

Accident at Three Mile Island Station. March 20, 1979

Most people, barely hearing the expression "nuclear catastrophe", 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 accident at the Chernobyl nuclear power plant, this particular incident was considered the largest in the history of nuclear energy.

Due to the leakage of coolant from the circulation system around the reactor, the cooling of nuclear fuel was completely stopped. The system heated up to such an extent 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 from the nuclear fuel got into the air and began to circulate through the ventilation system of the station, after which they entered the atmosphere. However, when compared with the Chernobyl disaster, everything here cost little victims. Only noble radioactive gases and a small part of iodine-131 got into the air.

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

The US authorities have decided not to close the power plant. The first power unit is still in operation.

Kyshtym accident. September 29, 1957

Another industrial accident with the release of radioactive substances occurred in 1957 at the Soviet Mayak enterprise 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 the storage of 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 the 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, which maintains the stability of sealed containers with nuclear mass.

One of the containers with a high content of radioactive nitrate-acetate salts has undergone self-heating. The sensor system could not fix this, because it simply rusted due to the negligence of workers. As a result, there was an explosion of a container with a volume of more than 300 cubic meters, 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 carry it over the nearby territory in a northeasterly direction. In just a few hours, radioactive fallout spread hundreds of kilometers and formed a kind of strip with a width of 10 km. A territory with an area of ​​23 thousand square kilometers, where almost 270 thousand people lived. Tellingly, due to weather conditions, the Chelyabinsk-40 object itself was not damaged.

The Commission for the Elimination of Consequences of Emergencies decided to evict 23 villages, the total population of which was almost 12,000 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 on this territory.

Radioactive contamination in Goiania. September 13, 1987

Undoubtedly, one should not underestimate the danger of nuclear energy, where scientists work with large volumes of nuclear fuel and complex devices. But even more dangerous is radioactive materials in the hands of people who don't know what they're dealing with.

In 1987, in the Brazilian city of Goiânia, 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 did not 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 landfill owner 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 an 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 the parts of the part, touched the powder of cesium chloride and even rubbed it on the skin. They liked the pleasant glow. It got to the point that pieces of radioactive material began to be passed to each other as gifts. Due to the fact that radiation in such doses does not have an instant effect on the body, no one suspected something was wrong, and the powder was distributed among the residents of the city for two weeks.

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

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

Fukushima disaster. March 11, 2011

The explosion at the Fukushima nuclear power plant in Japan on March 11, 2011 was equated on a scale of danger to the Chernobyl disaster. Both accidents received 7 points on the international scale of nuclear events.

The Japanese, who at one time became victims of Hiroshima and Nagasaki, have now received in their history another catastrophe on a planetary scale, 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. Nearly 16,000 people died as a result of the collapses.

Shocks at a depth of more than 32 km paralyzed the work of a fifth of all power units in Japan, which were under the control of automation and provided for such a situation. But the giant tsunami that followed the earthquake completed the job. In some places, the wave height reached 40 meters.

The earthquake disrupted the operation of several nuclear power plants at once. For example, the Onagawa nuclear power plant survived the fire of the power unit, but the staff managed to correct the situation. At Fukushima-2, the cooling system failed, which was repaired in time. Fukushima-1 suffered the most, 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 an earthquake. It would seem that the computers worked reliably and prevented trouble, but even in a shutdown 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 disabled the reactor's emergency cooling system, causing the diesel generator sets to stop working. Suddenly, the station staff was 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 cool the red-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 stand it and a series of explosions rang out, causing the collapse of the power units. In addition, the 4th power unit caught fire.

Radioactive metals and gases rose into the air, spread over the nearby territory and fell into the waters of the ocean. The products of combustion from the storage of nuclear fuel rose to a height of several kilometers, carrying radioactive ash hundreds of kilometers around.

To eliminate the consequences of the accident at Fukushima-1, tens of thousands of people were involved. Urgent decisions were needed from scientists on how to cool the red-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 place left for such tanks. The problem with pumping out radioactive water from reactors has not yet been resolved, so there is no guarantee that it will not fall into the oceans or the soil under the station as a result of a new earthquake.

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

At the moment, special systems have been developed for the decontamination of contaminated water, which make it possible to neutralize water from tanks and reuse it for cooling reactors, but the efficiency of such systems is extremely low, and the technology itself is still underdeveloped.

Scientists have developed a plan that provides for the extraction of 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 the extraction of molten reactor fuel from the circuits of the system is 2020.
After the disaster at the Fukushima-1 nuclear power plant, more than 120 thousand residents of nearby territories were evacuated.

Radioactive contamination in Kramatorsk. 1980-1989

Another example of human negligence in the handling of 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.

In the late 70s, in one of the mining quarries in 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 a panic among the management, because rubble from this quarry was delivered, incl. and to Moscow. By personal order of Brezhnev, the mining of rubble 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 into one of the walls of the house along with rubble.

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

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

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

On April 26, 1986, an explosion occurred at the 4th power unit of the Chernobyl Nuclear Power Plant (NPP). The reactor core was completely destroyed, the building of the power unit partially collapsed, and there was a significant release of radioactive materials into the environment.

The resulting cloud carried the radionuclides over most of Europe and the Soviet Union.

Directly during the explosion, one person died, another died in the morning.

Subsequently, 134 employees of the nuclear power plant and rescue teams developed radiation sickness. 28 of them died during the following months.

Until now, this accident is considered the worst accident at a nuclear power plant in history.However, such stories happened not only on the territory of the former USSR.

Below are the top 10 worst accidents at nuclear power plants.

10. "Tokaimura", Japan, 1999

Level : 4
The accident at the nuclear facility "Tokaimura" occurred on September 30, 1999 and resulted in the death of three people.
At that time, it was the most serious accident in Japan related to the peaceful use of nuclear energy.
The accident happened at the small radiochemical plant of JCO, a division of Sumitomo Metal Mining, in Tokai Township, Naka County, Ibaraki Prefecture.
There was no explosion, but the result of the nuclear reaction was intense gamma and neutron radiation from the sump, which triggered an alarm, after which actions began to localize the accident.
In particular, 161 people were evacuated from 39 residential buildings within a radius of 350 meters from the enterprise (they were allowed to return to their homes after two days).
11 hours after the start of the accident, a gamma radiation level of 0.5 millisieverts per hour was recorded at one of the sites outside the plant, which is approximately 4167 times higher than the natural background.
Three workers who directly worked with the solution were heavily irradiated. Two died a few months later.
In total, 667 people were exposed to radiation (including plant workers, firefighters and rescuers, as well as local residents), but, with the exception of the three workers mentioned above, their radiation doses were insignificant.

9. Buenos Aires, Argentina, 1983

Level : 4
The RA-2 installation was located in Buenos Aires in Argentina.
A qualified operator, with 14 years of experience, was alone in the reactor hall and performed operations to change the configuration of the fuel.
The retarder was not drained from the tank, although this was required by the instructions. Instead of removing the two fuel cells from the tank, they were placed behind a graphite reflector.
The fuel configuration was complemented by two regulating elements without cadmium plates. Critical condition was evidently reached when the second of these was being set up, as it was found to be only partly submerged.
The burst of power gave from 3 to 4.5 × 1017 divisions, the operator received an absorbed dose of gamma radiation of about 2000 rad and 1700 rad of neutron radiation.
Irradiation was extremely uneven, the upper right side of the body was more irradiated. The operator lived after that for two days.
Two operators who were in the control room received doses of 15 rad of neutron and 20 rad of gamma radiation. Six others received smaller doses of about 1 rad, and nine more received less than 1 rad.

8. Saint Laurent, France, 1969

Level : 4
The first gas-cooled uranium-graphite reactor of the UNGG type at the Saint Laurent nuclear power plant was put into operation on March 24, 1969. Six months later, one of the most serious incidents occurred at nuclear power plants in France and the world.
50 kg of uranium placed in the reactor began to melt. The event was classified as Grade 4 on the International Nuclear Event Scale (INES), making it the most serious incident in the history of French nuclear power plants.
As a result of the accident, about 50 kg of molten fuel remained inside the concrete case, so the leakage of radioactivity outside it was insignificant and no one was injured, but it was necessary to shut down the unit for almost a year to clean the reactor and improve the refueling machine.

7. NPP SL-1, USA, Idaho, 1961

Level : 5
SL-1 is an American experimental nuclear reactor. It was developed by order of the US Army, for the power supply of isolated radar stations beyond the Arctic Circle and for the line of early radar detection.
The development was carried out as part of the Argonne Low Power Reactor (ALPR) program.
On January 3, 1961, a control rod was removed at the reactor during work for unknown reasons, an uncontrolled chain reaction began, the fuel heated up to 2000 K, and a thermal explosion occurred that killed 3 employees.
This is the only radiation accident in the United States that resulted in the immediate death of people, the meltdown of the reactor and the release of 3 TBq of radioactive iodine into the atmosphere.

6. Goiania, Brazil, 1987

Level : 5
In 1987, a part from a radiotherapy unit containing the radioactive isotope cesium-137 in the form of cesium chloride was stolen from an abandoned hospital by looters, after which it was thrown away.
But after some time, it was discovered in a landfill and attracted the attention of the owner of the landfill, Devar Ferreira, who then brought the found medical source of radioactive radiation to his house and invited neighbors, relatives and friends to look at the glowing blue powder.
Small fragments of the source were picked up, rubbed on the skin, passed on to other people as gifts, and as a result, the spread of radioactive contamination began.
For more than two weeks, more and more people came into contact with powdered cesium chloride, and none of them knew about the danger associated with it.
As a result of the widespread distribution of highly radioactive powder and its active contact with various objects, a large amount of material contaminated with radiation accumulated, which was later buried in the hilly area of ​​one of the suburbs of the city, in the so-called near-surface storage.
This area can only be used again after 300 years.

5. NPP Three Mile Island, USA, Pennsylvania, 1979

Level : 5
The accident at the Three Mile Island nuclear power plant is the largest accident in the history of commercial nuclear energy in the United States, which occurred on March 28, 1979 at the second power unit of the station due to a leak of the primary coolant of the reactor plant that was not detected in a timely manner and, accordingly, the loss of nuclear fuel cooling.
During the accident, about 50% of the reactor core melted, after which the power unit was never restored.
The premises of the nuclear power plant were subjected to significant radioactive contamination, but the radiation consequences for the population and the environment turned out to be insignificant. The accident was assigned level 5 on the INES scale.
The accident exacerbated an already existing crisis in the US nuclear industry and caused a surge in anti-nuclear sentiment in society.
Although all this did not immediately stop the growth of the US nuclear energy industry, its historical development was stopped.
After 1979 and until 2012, no new licenses for the construction of nuclear power plants were issued, and the commissioning of 71 previously planned plants was canceled.

4. Windscale, UK, 1957

Level : 5
The Windscale accident is a major radiation accident that occurred on October 10, 1957 at one of the two reactors of the Sellafield nuclear complex, in Cumbria, northwest England.
As a result of a fire in an air-cooled graphite reactor for the production of weapons-grade plutonium, a large (550-750 TBq) release of radioactive substances occurred.
The accident is level 5 on the International Nuclear Event Scale (INES) and is the largest in the history of the UK nuclear industry.

3. Kyshtym, Russia, 1957

Level : 6
The "Kyshtym accident" is the first man-made radiation emergency in the USSR that occurred on September 29, 1957 at the Mayak chemical plant located in the closed city of Chelyabinsk-40 (now Ozyorsk).
September 29, 1957 at 4:2 pm2 due to the failure of the cooling system, an explosion of a 300 cu. m, which contained about 80 cubic meters. m of highly radioactive nuclear waste.
The explosion, estimated at tens of tons of TNT, destroyed the tank, the concrete floor 1 m thick and weighing 160 tons was thrown aside, about 20 million curies of radioactive substances were released into the atmosphere.
Part of the radioactive substances was raised by the explosion to a height of 1-2 km and formed a cloud consisting of liquid and solid aerosols.
Within 10-12 hours, radioactive substances fell out over a distance of 300-350 km in the northeast direction from the explosion site (in the direction of the wind).
The territory of several enterprises of the Mayak plant, a military camp, a fire department, a colony of prisoners, and then an area of ​​​​23 thousand square meters turned out to be in the zone of radiation contamination. km with a population of 270 thousand people in 217 settlements of three regions: Chelyabinsk, Sverdlovsk and Tyumen.
Chelyabinsk-40 itself was not damaged. 90% of radiation pollution fell on the territory of the Mayak chemical plant, and the rest dissipated further.

2. NPP "Fukushima", Japan, 2011

Level : 7
The accident at the Fukushima-1 nuclear power plant is a major radiation accident of the maximum level 7 on the International Nuclear Event Scale, which occurred on March 11, 2011 as a result of the strongest earthquake in the history of Japan and the tsunami that followed it.
The earthquake and tsunami hit disabled external power supplies and backup diesel generators, which caused the inoperability of all normal and emergency cooling systems and led to the melting of the reactor core at power units 1, 2 and 3 in the first days of the accident.
A month before the accident, the Japanese authorities approved the operation of power unit No. 1 for the next 10 years.
In December 2013, the nuclear power plant was officially closed. On the territory of the station, work is underway to eliminate the consequences of the accident.
Japanese nuclear engineers estimate that bringing the facility to a stable, safe state could take up to 40 years.
Financial damage, including cleanup costs, decontamination costs and compensation, as of 2017 is estimated at $189 billion.
Since the work to eliminate the consequences will take years, the amount will increase.

1. Chernobyl nuclear power plant, USSR, 1986

Level : 7
Chernobyl disaster - the destruction on April 26, 1986 of the fourth power unit of the Chernobyl nuclear power plant, located on the territory of the Ukrainian SSR (now - Ukraine).
The destruction was explosive, the reactor was completely destroyed, and a large amount of radioactive substances was released into the environment.
The accident is regarded as the largest of its kind in the history of nuclear energy, both in terms of the estimated number of people killed and affected by its consequences, and in terms of economic damage.
During the first three months after the accident, 31 people died; long-term effects of exposure, identified over the next 15 years, caused the death of 60 to 80 people.
134 people suffered from radiation sickness of varying severity.
More than 115 thousand people from the 30-kilometer zone were evacuated.
Significant resources were mobilized to eliminate the consequences, more than 600 thousand people participated in the liquidation of the consequences of the accident.

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