The world's largest accident occurred at the Chernobyl nuclear power plant on April 26, 1986. A technological experiment to study the possibility of supplying pumps with energy from the station itself led directly to the accident (previously this was done from the city network). At 1:24 a.m., the nuclear reactor of the fourth unit went out of control, exploded and caught fire.

The total release of radioactive substances in environment is estimated to be 50 MCi, which is 3.5% of the total amount of radioactive substances in the reactor. 96.5% or approximately 1380 MCi remained inside the reactor. Since 1Ci = = 3.7 * 10 10 Bq = 3.7 * 10 10 disintegrations per second, then immediately after the accident, 50 * 10 6 * 3.7 * 10 10 decay / s = 1.85 * 10 occurred in the environment 18 ras / s

According to the Organization for Economic Cooperation in Europe, the following radioactive substances were found in the environment: the elentisotopperiod of the half -life of cesium137 CS37 years old cesium134 cs2.1 years iodine iodine133 xenon133 xe5.3 days Molibden99 MO2.4 zR64 days of ruts104 ruts10 .7 DAYS CERIUM141 CE32.5 DAYS CERIUM144 CE284 DAYS STRONTIUM89 SR59.5 DAYS STRONTIUM90 SR29.2YEARS PLUTONIUM239 PU24000 YEARS

Today, 20 years later, radioactive cesium and strontium with a half-life of 30 years are of particular danger. Currently, more than 60% of the initial amount of these elements are in the environment, participating in the biological cycle of substances. Extremely long-lived plutonium poses a particular danger. During the fire, plutonium and soot formed "hot particles" that are easily carried by the wind and, when ingested, settle in the lungs, causing serious internal radiation exposure. Now, 20 years after the accident, about 0.1% of the plutonium ejected from the reactor has decayed, 99.9% is still in the environment.

As a result of the accident, the territories of Belarus (23%), Ukraine (4.8%), Russia (0.5%) were affected. 264,000 hectares of land have been taken out of agricultural circulation. 600 thousand people were directly affected by the Chernobyl accident. The first victims of Chernobyl were heroes - firefighters who extinguished the reactor immediately after the explosion. There are 31 of them. At the cost of their lives, they did not allow the fire to spread to the nearby III block. Then the consequences of the accident would be difficult to imagine.

The Chernobyl disaster does not have one - the only reason. The catastrophe became possible as a result of a number of mistakes and miscalculations - political, managerial and technical. 1. The danger of nuclear power was underestimated. This led to the decision to build nuclear power plants on a massive scale. 2. When designing nuclear power plant made a number of miscalculations. 3. Low qualification and low discipline of the personnel The experiment, which failed during the day, was continued at night by the young shift supervisors, in the absence of the chief specialists of the station, which led to a gross violation of the instructions (in particular, control rods were left in the working zone of the reactor much less than the critical norm. ) 4. In addition, untimely notification of people about the accident exacerbated the consequences and significantly increased the number of victims.

The consequences of Chernobyl are global and eternal. Global, because Chernobyl radiation has spread throughout the planet. Eternal, because polluted lands will remain dangerous for tens and even hundreds of thousands of years. Main lesson the tragedy is that you cannot rely on technology, no matter how reliable it may seem. Blind faith in the safety of the “peaceful atom” led to disaster.

By the May holidays, everything was ready for the shop windows described with slogans, the scenarios for the demonstrations had already been submitted for approval by the authorities, and the festive menu was being compiled in restaurants. Everyone was anxiously waiting for 3 days off. Dreams about the holidays collapsed on April 26, when a terrible explosion at the Chernobyl nuclear power plant thundered, changing the lives of all the inhabitants of this youngest and most beautiful city in the USSR. Today it is an exclusion zone, from the very name of which, goosebumps go. The city is surrounded by barbed wire and entry is allowed only with passes ... By the May holidays, everything was ready with the shop windows described by slogans, the scenarios for the demonstrations had already been submitted for approval by the authorities, and the festive menu was compiled in restaurants. Everyone was anxiously waiting for 3 days off. Dreams about the holidays collapsed on April 26, when a terrible explosion at the Chernobyl nuclear power plant thundered, changing the lives of all the inhabitants of this youngest and most beautiful city in the USSR. Today it is an exclusion zone, from the very name of which, goosebumps go. The city is surrounded by barbed wire and entry is allowed only with passes...

Chernobyl accident - the destruction on April 26, 1986 of the fourth power unit of the Chernobyl nuclear power plant, located on the territory of Ukraine (at that time the Ukrainian SSR). The destruction was of an explosive nature, the reactor was completely destroyed, and a large number of radioactive substances. The accident is regarded as the largest of its kind in the history of nuclear power, both in terms of the estimated number of people killed and affected by its consequences, and in terms of economic damage. At the time of the accident, the Chernobyl nuclear power plant was the most powerful in the USSR. The real number of deaths during the first 3 months is estimated at 31 people; the long-term effects of exposure, identified over the next 15 years, caused the death of 60 to 80 people. Chernobyl accident - the destruction on April 26, 1986 of the fourth power unit of the Chernobyl nuclear power plant, located on the territory of Ukraine (at that time the Ukrainian SSR). 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 power, both in terms of the estimated number of people killed and affected by its consequences, and in terms of economic damage. At the time of the accident, the Chernobyl nuclear power plant was the most powerful in the USSR. The real number of deaths during the first 3 months is estimated at 31 people; the long-term effects of exposure, identified over the next 15 years, caused the death of 60 to 80 people.

As a result of the explosion at the Chernobyl nuclear power plant, an area of ​​​​4000 sq. km was cordoned off. The city of Pripyat and all settlements within a radius of 30 km were completely evacuated. But some who did not accept life in a foreign land returned immediately ... As a result of the explosion at the Chernobyl nuclear power plant, the territory with an area of ​​4000 sq. km. The city of Pripyat and all settlements within a radius of 30 km were completely evacuated. But some who did not reconcile themselves to life in a foreign land returned immediately ...

At approximately 1:24 am on April 26, 1986, a release occurred at the 4th power unit of the Chernobyl nuclear power plant, which completely destroyed the reactor. The building of the power unit partially collapsed, killing 2 people, the operator of the MCP pumps (Main circulation pump) Valery Khodemchuk (the body was not found, heaped under the debris of two 130-ton drum separators), and Vladimir Shashenok, an employee of the commissioning enterprise (died of a fracture of the spine and numerous burns at 6:00 in the Pripyat Medical Unit, on the morning of April 26). A fire broke out in various rooms and on the roof. Subsequently, the remnants of the core melted. A mixture of molten metal, sand, concrete and fuel particles spread over the sub-reactor rooms. As a result of the accident, radioactive substances were released into the environment, including isotopes of uranium, plutonium, iodine-131 (half-life 8 days), cesium-134 (half-life 2 years), cesium-137 (half-life 33 years), strontium -90 (half-life 28 years). At approximately 1:24 am on April 26, 1986, a release occurred at the 4th power unit of the Chernobyl nuclear power plant, which completely destroyed the reactor. The building of the power unit partially collapsed, killing 2 people, the operator of the MCP pumps (Main circulation pump) Valery Khodemchuk (the body was not found, heaped under the debris of two 130-ton drum separators), and Vladimir Shashenok, an employee of the commissioning enterprise (died of a fracture of the spine and numerous burns at 6:00 in the Pripyat Medical Unit, on the morning of April 26). A fire broke out in various rooms and on the roof. Subsequently, the remnants of the core melted. A mixture of molten metal, sand, concrete and fuel particles spread over the sub-reactor rooms. As a result of the accident, radioactive substances were released into the environment, including isotopes of uranium, plutonium, iodine-131 (half-life 8 days), cesium-134 (half-life 2 years), cesium-137 (half-life 33 years), strontium -90 (half-life 28 years). Graphite, metal and nuclear fuel What happened after the explosion...

In the first days after the accident, the population of the 10-kilometer zone was evacuated. In the following days, the population of other settlements 30 km zone. It was forbidden to take things with you, many were evacuated in home clothes. In order not to fan the panic, it was reported that the evacuees would return home in three days. Pets were not allowed to be taken with them, subsequently, from among the military and local hunters, detachments were formed to shoot abandoned domestic animals, as well as wild animals. In the first days after the accident, the population of the 10-kilometer zone was evacuated. In the following days, the population of other settlements of the 30-kilometer zone was evacuated. It was forbidden to take things with you, many were evacuated in home clothes. In order not to fan the panic, it was reported that the evacuees would return home in three days. Pets were not allowed to be taken with them, subsequently, from among the military and local hunters, detachments were formed to shoot abandoned domestic animals, as well as wild animals.

Until 2000, the 3rd power unit continued its work, currently 3,000 people are in the exclusion zone - ecologists, geologists and other specialists, 300 people out of these three thousand are residents who remained ... Until 2000, the 3rd power unit continued its work, currently, 3,000 people are in the exclusion zone - environmentalists, geologists and other specialists, 300 people of these three thousand are residents who remained ... Control panel 4 reactors 3rd power unit Corridor connecting control room 4, turbine hall and reactor shop.

Specialists sent to carry out work on the emergency unit and around it, as well as military units, both regular and composed of urgently called up reservists, began to arrive in the 30-kilometer zone around the Chernobyl nuclear power plant. All of them were later called "liquidators". The liquidators worked in the danger zone in shifts: those who had accumulated the maximum allowable dose of radiation left, and others came to take their place. The main part of the work was completed in years, about a person took part in them. The total number of liquidators (including subsequent years) amounted to about 30-kilometer zone around the Chernobyl nuclear power plant, specialists sent to carry out work on the emergency unit and around it, as well as military units, both regular and composed of urgently called up reservists, began to arrive. All of them were later called "liquidators". The liquidators worked in the danger zone in shifts: those who had accumulated the maximum allowable dose of radiation left, and others came to take their place. The main part of the work was completed in years, about a person took part in them. The total number of liquidators (including subsequent years) was about

Target:

1. Consideration of the problem of using the atom for peaceful purposes and overcoming possible crisis moments.

2. Demonstration, using the example of Chernobyl, that man-made disasters are caused not only by a failure in technology, in mechanisms, but also by incorrect actions of personnel and other NPP employees

3. Development in students of a sense of responsibility for the fate of their country, their compatriots, understanding that each person should approach the performance of his work with high quality and seriously.

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Slides captions:

GOU SOSH 1981 Moscow 25 years of the accident at the Chernobyl nuclear power plant Physics teacher Alikueva Elena Anatolyevna 2011

Chernobyl nuclear power plant Complete destruction of the Chernobyl reactor, Pripyat, Ukrainian SSR A radioactive cloud passed over the USSR, Eastern Europe, Scandinavia Chernobyl accident - April 26, 1986

Release to the environment Uranium isotopes Plutonium Iodine - 131 (half-life - 8 days) Cesium - 134 (half-life - 2 years) Cesium - 137 (half-life - 33 years) Strontium - 190 (half-life - 28 years)

Chronology of events At 1:23:39 - emergency protection signal (AZ-5) Then a signal of a rapid increase in power Recording systems fail Emergency protection rods stopped 1:23:47 - 1:23:50 (3 seconds!) - explosion , the reactor is completely destroyed

Presumable reasons were expressed: Hydrogen explosion - chemical nature of the explosion Thermal explosion - nuclear nature Steam explosion INSAG “... the accident was the result of an unlikely coincidence of a number of violations of the rules and regulations by the operating personnel, the accident acquired catastrophic consequences due to the fact that the reactor was brought into an unscheduled state. » Causes of the accident

Reactor deficiencies As of April 1986, the RBMK reactor had dozens of violations and deviations from the safety rules in force at that time. Due to the physical and design parameters of the active zone, erroneously chosen by its developers, the reactor was a dynamically unstable system with respect to the disturbance both in terms of power and steam content.

Operators' mistakes Thus, the most significant mistakes of the operational personnel should be called: interpretation of the proposed tests as electrical; improper preparation of the test program, including in terms of regulating safety measures; significant deviations from the program at the stage of preparation for the experiment and its implementation; reactor emergency protection

Consequences of the accident

Informing the population

Elimination of the consequences of the accident

Impact of the accident on human health

Irradiation doses

Cancer The thyroid gland is one of the organs most at risk of developing cancer as a result of radioactive contamination, because it accumulates iodine-131; especially high risk for children Over 4,000 cases of thyroid cancer were reported between 1990 and 1998 among those under the age of 18 at the time of the accident

An increase in the number of congenital pathologies was found in various regions of Belarus between 1986 and 1994. Child mortality is very high in all three countries affected by the Chernobyl accident.

Other diseases Cataracts Cardiovascular diseases Decreased immunity

Dead city 25 years later

Memory of the dead

This must not happen again!

Causes of the accident At power unit No. 4 of the Chernobyl nuclear power plant on April 26, 1986 at 01:23:40, the reactor operator pressed the reactor shutdown button. After that, the reactor, instead of stopping, began to rapidly increase its power, turned into a kind of nuclear bomb, and exploded at 1 hour 23 minutes 47 seconds. After 1-2 seconds, a second explosion followed, and the reactor collapsed. The accident occurred due to design flaws in the control rods. nuclear reactor. These rods were made in such a way that when they were introduced into the reactor core, they did not slow down the nuclear reaction, as they should, but, on the contrary, accelerated it for several seconds.

The accident at the Chernobyl nuclear power plant was the largest environmental disaster of the twentieth century. The radiation released during the explosion made a life-threatening area of ​​5 million hectares, occupied mainly by rural fields. A dangerous amount of radionuclides has accumulated in the silt of the Pripyat and Dnieper rivers, the Kyiv reservoir. Decades after the accident, their content is 10-100 times higher than the permissible levels. Today, the danger is not only the sarcophagus of the fourth power unit, which transmits radiation to the outside. Around the Chernobyl nuclear power plant there are more than 100 nuclear waste repositories. The consequences of the man-made disaster affected the health of several generations and will continue to be felt for many years to come.

Pripyat is a satellite city at the Chernobyl nuclear power plant. It was built to serve a nuclear power plant. After assessing the scale of radioactive contamination, it became clear that the evacuation of the city of Pripyat was necessary. The evacuation was carried out on April 27, 1986, only 36 hours after the explosion. People were forbidden to take things with them, many were evacuated in home clothes. To avoid panic, people were told that they would return home in three days. Pets were not allowed to be taken with them. Now, this is a ghost town located in northern Ukraine, 3 km from the Chernobyl nuclear power plant near the border with Belarus. As a result of the accident, a 30-kilometer exclusion zone was created, hundreds of small settlements were buried with heavy equipment.

Mutation like

Memory The liquidators worked in the danger zone gradually: those who had accumulated the maximum allowable dose of radiation left, and others came to take their place. Most of the work was completed in the first year. The total number of liquidators was about 600 thousand people. Many monuments were erected in memory of the Chernobyl accident and as a tribute to the liquidators. The monument to Nizhny Novgorod residents - participants in the liquidation of the consequences of the disaster was opened on September 10, 2009 at the Old Fair Cathedral.

In the city of Chernobyl, a monument to firefighters was erected, near the fire station. Firefighters from this unit were among the first to arrive at the scene of the accident.