Man-made disasters: Chernobyl and Fukushima. Fukushima and Chernobyl: comparison

Nuclear energy is a virtually inexhaustible source of inexpensive electricity, which has been saving the world from energy hunger since the middle of the last century. But nuclear power plants are not only rivers of cheap electricity, but also the most terrible radiation disasters that can destroy an entire country. Such a catastrophe was avoided at the Three Mile Island nuclear power plant, irreparable damage was caused by Chernobyl, and in 2011 a blow was unexpectedly struck by the Japanese Fukushima-1 plant, which still keeps the world in suspense.

Accident at the Fukushima-1 nuclear power plant

An object: Fukushima-1 Nuclear Power Plant, Okuma City, Fukushima Prefecture, Japan.

Fukushima-1 was one of the most powerful nuclear power plants in the world. It consists of 6 power units, which before the accident supplied up to 4.7 gigawatts of energy to the electrical network. At the time of the disaster, only reactors 1, 2 and 3 were in working order, reactors 4, 5 and 6 were shut down for scheduled repairs, and the fuel from the fourth reactor was completely unloaded and was in the cooling pool. Also, at the time of the disaster, in the cooling pools of each power unit there was a small supply of fresh fuel and a fairly large amount of spent fuel.

Victims: 2 died and 6 were injured at the time of the disaster, another 22 people were injured during the liquidation of the accident, 30 people received dangerous doses of radiation.

Causes of the disaster

The accident at the Fukushima-1 nuclear power plant is the only radiation disaster caused by a natural disaster. And it would seem that only nature can be blamed here, but, surprisingly, people are also to blame for the accident.

It is interesting that the notorious earthquake that occurred on March 11, 2011 cannot be considered the main cause of the Fukushima accident - after the first tremors, all reactors operating at the nuclear power plant were shut down by the emergency protection system. However, after about an hour, the station was covered by a tsunami wave almost 6 meters high, which led to fatal consequences - the normal and emergency reactor cooling systems were turned off, and then a chain of explosions and radiation emissions followed.

It's all to blame for the wave, which disabled all power sources for cooling systems and also flooded backup diesel power plants. The reactors, deprived of cooling, began to heat up, their core melted, and only the selfless actions of the plant personnel saved the world from a new Chernobyl. Although Fukushima could have become worse than Chernobyl - three reactors at the Japanese plant were in an emergency situation.

What is people's fault? Everything is very simple: when designing the station (and construction began back in 1966), the locations for the location of diesel power plants were chosen incorrectly and the supply of electricity to the standard reactor cooling systems was not thought out. It turned out that the reactors withstood colossal loads, but the auxiliary systems failed from the first blow of the elements. This can be compared to installing a new armored door with old wooden jambs - the door cannot be broken into, and the hinges are unlikely to hold out a burglar...

Chronicle of events

The elements struck the first blow in 14.46 local time. The reactors of the Fukushima-1 nuclear power plant (power units No. 1, 2 and 3) that were operating at that time were shut down by activated emergency protection systems. And everything would have worked out, but approximately 15.36 The dam protecting the station from the sea was overtaken by a tsunami wave 5.7 meters high.

The wave easily overflowed the dam, penetrated the territory of the nuclear power plant, causing various damages, began to flood buildings and premises, and 15.41 The water disabled the standard power supply systems of the reactor cooling systems and emergency diesel power plants. It is this moment that can be considered the zero point of the disaster.

As is known, reactors continue to emit large amounts of heat even after shutdown - this is mainly due to the ongoing decay of highly active fission products of nuclear fuel. And, despite the fact that the reactor is actually “turned off” (nuclear chain reactions are stopped), megawatts of thermal energy are released in it, capable of melting the core and leading to disaster.

This is exactly what happened at three reactors in Fukushima. Each of them released from 4 to 7 megawatts of energy, but due to the shutdown of the cooling systems, this heat was not removed anywhere. Therefore, in the first hours after the tsunami in the active zones of reactors 1, 2 and 3, the water level dropped significantly and at the same time the pressure increased (the water simply turned into steam), and, as experts suggest, some of the fuel assemblies with nuclear fuel melted.

Already on the evening of March 11 a significant increase in pressure was recorded in the containment of power unit No. 1, which was twice the permissible limit. And in 15.36 March 12 The first explosion occurred, as a result of which the power unit building was partially destroyed, but the reactor was not damaged. The cause of the explosion was the accumulation of hydrogen, which is released during the interaction of superheated steam and zirconium shells of fuel assemblies.

On the second day after the disaster - on the morning of March 12- it was decided to cool reactor No. 1 by supplying sea water. At first they wanted to abandon this measure, since sea water, saturated with salts, accelerates the corrosion process, but there was no other way out; there was simply nowhere to get many thousands of tons of fresh water.

On the morning of March 13 An increase in pressure was recorded inside reactor No. 3, and the supply of sea water to it also began. However at 11.01 am on March 14 an explosion occurred in the third power unit (as in the first power unit, hydrogen exploded), which did not lead to serious damage. In the evening of the same day, the supply of sea water inside reactor No. 2 began, but 6.20 am March 15 and an explosion occurred in its premises, which did not cause serious destruction. At the same time, an explosion occurred in power unit No. 4, supposedly in the nuclear waste storage facility. As a result, the structure of the fourth power unit received serious damage.

After a chain of these accidents and a significant increase in radiation on the territory of the station, a decision was made to evacuate the personnel. There were only 50 engineers left in Fukushima to solve current problems. However, employees of third-party companies were involved in eliminating the consequences of the accident, pumping water, laying electrical cables, etc.

Due to the lack of electricity, the cooling pools in which the fuel assemblies of the fourth, fifth and sixth reactors were located also began to pose a threat. The water in the pools did not circulate, its level was falling, and on March 16, the operation to pump water into them began. The next day, the situation became extremely dangerous, and several tens of tons of water were sent from helicopters to the storage pools of blocks No. 3 and 4.

From the first day, work was carried out to connect power to the station from a power line located one and a half kilometers away. It must be said that the diesel power plant of the sixth power unit continued to operate, and it was periodically connected to other power units, but its power was not enough. And only by March 22, power supply to all six power units was established.

It was the injection of sea and then fresh water into the reactors that became the main strategy for stabilizing the situation. Water was supplied to the reactors until the end of May, when it was possible to restore the closed cooling system. Only on May 5, people entered power unit No. 1 for the first time after the accident - for only 10 minutes, since the level of radioactive contamination was very high.

It was only possible to completely shut down the reactors and put them into cold shutdown mode by mid-December 2011.

Consequences of the Fukushima accident

The accident at the Fukushima-1 nuclear power plant had the most disastrous consequences, which, surprisingly, arose due to the fault of people.

The most unpleasant thing in all radiation accidents is the contamination of air, water and land with highly active fission products of nuclear fuel. That is, radiation contamination of the area. A certain contribution to this contamination was made by explosions at power units that occurred from March 12 to 15, 2011 - the steam released from the reactor containments carried a certain amount of radionuclides that settled around the station.

However, the greatest pollution was caused by seawater, which was pumped into the reactors in the first week after the accident. After all, this water, passing through the reactor core, again ended up in the ocean. As a result, by March 31, 2011, the radioactivity of ocean water at a distance of 330 meters from the station exceeded the permissible limit by 4385 times! Currently, this figure has decreased significantly, but the radioactivity of the coast near the station is almost 100 times higher than all permissible standards.

Releases of radioactive substances forced the evacuation of people from a 2-kilometer zone around the station on March 11, and by March 24, the radius of the evacuation zone increased to 30 km. In total, according to various estimates, from 185 to 320 thousand people were evacuated, but this number also includes those evacuated from areas that suffered serious damage from the earthquake and tsunami.

As a result of water contamination, fishing has been prohibited in a number of areas, and a ban has been placed on the use of land in a 30-kilometer zone around Fukushima-1. Currently, active work is underway to decontaminate the soil in this area, however, due to high concentrations of radionuclides, the simplest solution was to remove the top layer of soil and its subsequent destruction. Due to this local residents It is forbidden to return to their homes, when this can be done is unknown.

As for the impact of the accident on human health, there are no particular concerns about this. It is believed that even residents of a 2-kilometer zone received minimal radiation doses that did not pose a danger - after all, the main contamination of the area occurred after the evacuation. However, according to experts, the true consequences of the disaster on human health will not be clear until 15 years from now.

The accident at the Fukushima-1 nuclear power plant had consequences of a completely different kind. Japan, due to the shutdown of all its nuclear power plants, was forced to significantly increase electricity production at traditional thermal power plants. But most importantly, the accident has caused fierce debate over the need for nuclear energy in Japan, and it is quite possible that the country will abandon the use of nuclear power plants altogether by the 2040s.

Now

The station is currently inactive, but work is underway to maintain the reactors and cooling pools in a stable condition. The fact is that heating of nuclear fuel is still occurring (in particular, the water temperature in the pools reaches 50 - 60 degrees), which requires constant heat removal both from the reactors and from the pools with fuel and nuclear waste.

This state will persist at least until 2021 - during this time the most active decay products of nuclear fuel will disintegrate, and it will be possible to begin the operation to remove the molten cores from the reactors (the removal of fuel and waste from the cooling pools will be carried out at the end of 2013). And by the 2050s, the Fukushima-1 nuclear power plant will be completely dismantled and cease to exist.

Interestingly, reactors No. 5 and 6 are still operational, but their normal cooling systems are damaged and therefore cannot be used to generate electricity.

Currently, the station is constructing a sarcophagus over power unit No. 4; similar measures are planned to be taken in relation to other damaged reactors.

Thus, at the moment, the emergency station does not pose a danger, but huge amounts of money have to be spent to maintain this situation. At the same time, various incidents periodically occur at the station that could lead to a new accident. For example, on March 19, 2013, a short circuit occurred, as a result of which the emergency reactors and cooling pools were again left without cooling, but by March 20 the situation was corrected. And the cause of this incident was an ordinary rat!

The accident at the Fukushima-1 nuclear power plant attracted the attention of the whole world, causing fear and anxiety among people even on the other side Globe. And now each of us can personally see what is happening at the station - several web cameras are installed around it, transmitting images from key facilities of Fukushima-1 around the clock.

And we can only hope that the station employees will not allow new accidents, and all Japanese and half the world can sleep peacefully.

Animation of the processes that took place at the Fukushima nuclear power plant after the tsunami:

One of the most shocking tsunami videos:

We asked senior researcher at the Institute of Nuclear Power Plant Safety Problems of the National Academy of Sciences of Ukraine, Ph.D., to answer this question. — A.A. Sizova

As you know, on Saturday, March 12, an explosion occurred at the Fukushima-1 nuclear power plant in Japan. After the accident at Chernobyl nuclear power plant, which occurred in April 1986, any incidents at a nuclear power plant become the object of close public attention, which we see now.
Let's try to compare the scale and consequences of these two accidents and at the same time answer the question whether a second Chernobyl in Japan is possible in this case.
Let's start with the reactor design. Fukushima reactors - 1 are boiling water reactors (Boiling Water Reactor (BWR), the pressure in which is maintained by the reactor vessel, the moderator is water. The Chernobyl reactors are RBMK, the pressure in which is maintained in each channel separately, the moderator is graphite.
At the Chernobyl Nuclear Power Plant in April 1986, the reactor channels were damaged, fission products, along with irradiated graphite, were thrown to great heights by a powerful explosion that destroyed the reactor premises of the 4th block. Subsequently, graphite and fine particles of fuel and reactor structures continued to escape into the atmosphere until mid-May.

The collapse of the Chernobyl nuclear reactor after the accident in 1986

At the moment, it is not known for certain what happened at the Fukushima nuclear power plant, but according to media reports, after the explosion the reactor shell remained intact, which means there were no large-scale and prolonged emissions of fission products and spent fuel into the atmosphere.
If events in Japan follow the worst-case scenario, which consists of a simultaneous failure of the ventilation system and depressurization of the core, then this will be followed by a fairly large, but SHORT-TERM release, which will sharply decrease after pressure equalization. In the future, the emissions will be minimal, because no active processes (combustion) will occur in the reactor. This is the main difference from the Chernobyl accident, where after the complete destruction of the core, the release continued for weeks. However, incoming data on the radiation situation indicate that the core is sealed (not destroyed).

Schematic diagram of the reactor structure at the Fukushima-1 nuclear power plant (based on materials from euronuclear.org)

In addition, it is important that the prevailing wind in the Fukushima -1 area is towards the Pacific Ocean, while during emissions from the Chernobyl accident it blew in all directions, mainly in the north-west direction.
Thus, we can conclude that even despite the possible large release at Fukushima, the consequences for the population will be of a much smaller scale than it was in . People will receive (received) the main dose during the passage of the initial cloud; subsequently it will be minimal.

P.S.
As we have already written, the main parameter of the consequences of radiation accidents is the radiation situation in the surrounding areas. You can find out about the current level of background radiation. Read how to do this on the page “

The man-made activities of mankind may not leave the most attractive monument to our stay on Earth. With the development of high technologies in the modern world, man-made disasters have become more frequent. Chernobyl, Fukushima - their consequences turned out to be worse than Hollywood science fiction films about the end of the world. It is no longer possible to stop the process of environmental pollution with radioactive substances.

There is no such thing as safe nuclear power. Enormous temperatures, unfriendly substances and materials, as well as high energies create risks at any nuclear power plant. If you like to ride, prepare for the consequences, says radiation safety expert Maxim Shingarkin:

"Contrary to popular belief, the Japanese engineering discipline turned out to be based on American instructions from forty years ago. Reactors that are built from modern materials are more efficient. It was much safer to walk than to race in cars at a speed of 200 km per hour. And, of course, if there are cars with high reliability, they are, of course, safer."

The accident at the Chernobyl nuclear power plant demonstrated to the whole world how dangerous the consequences of such disasters can be. In 1986, no one was ready for this, they didn’t know what to do, there were no protective suits... It would seem that such lessons should not be in vain, but, nevertheless, at Fukushima-1 in the first six months they also didn’t know that do. Yes, and they still doubt it. A comparison of the two disasters leads to conclusions that are clearly not in favor of the Japanese. There are many reasons for this, but the main one is the difficulty in eliminating the consequences. The Japanese community cannot do anything about this problem on its own, says nuclear physics and nuclear energy specialist Igor Ostretsov:

"The entire international community must take part in this. And first of all the United States, which arranged this matter. The international community, however, is silent. This was due to fuel shortages. An alternative for the future is nuclear energy, which meets the requirements of the IAEA : unlimited resource base, fundamental absence of accidents, solution to the problem of non-proliferation and absence of radioactive waste. These technologies have, among other things, military application, which is being “reset” by the United States. Therefore, they prohibit working on this technology. Although we made a contract for them and gave them this technology as a military application."

There are no direct lessons from Chernobyl for Fukushima. The nature of the accidents is fundamentally different: the Chernobyl reactor burned down 99%, evaporated into the atmosphere and was scattered in the stratosphere into tiny particles. Only a small part of the nuclear materials ended up at the nuclear power plant site. In the case of the Japanese nuclear power plant, the reactor melted, and most of the harmful substances remained on the territory of the station. It is the spent nuclear fuel that complicates the situation.

The Japanese, of course, could take into account the Soviet experience in eliminating the consequences. Moreover, there are no specialists of this kind in the country. Repeated attempts were made to purify contaminated waters from radionuclides; they also tried to flood the reactor, removing heat from the coolants. But the amount of radioactive waste only increased. And treatment plants did not operate effectively for more than a matter of weeks. Unfortunately, Japan refused to finance international studies in this area, as well as discussing a grant program for engineers who could help clean up the consequences while massive pollution of the Pacific Ocean continues.

All science is prediction.

(Herbert Spencer)

You always need to know ten times more than what is needed directly for work today.

(Academician Yu.B. Khariton)

We must know much more about nature, about its essence, than we can currently use.

(Academician M.V. Keldysh)

As the complexity of a system increases, our ability to formulate precise and simultaneously meaningful statements about its behavior decreases, up to a certain threshold at which precision and significance become mutually exclusive.

In fact, it always turns out that the probability of accidents is much greater than what is considered by designers.

(A.D. Sakharov)

We need a new point of view, a new set of concepts and methods in which fuzziness is accepted as a universal reality of human existence.

Any ignorance is dangerous, and global ignorance is deadly for many.

An overview of the current state of the problem of nuclear energy safety is given based on materials from open domestic and foreign press. The main factors that have a direct impact on the uncertainty of risks at nuclear power plants (NPPs) are considered, starting with erroneous actions of the human operator and ending with unforeseen failures and failures of NPP equipment in emergencies and emergencies. A methodology for analyzing and assessing the risk of nuclear power plants is presented, which allows, under conditions of uncertainty, to link together (synthesis) the necessary diverse thematic information and modern computing technologies in order to manage the safety of nuclear power plants.

Key words: nuclear energy, nuclear power plant, human factor, hazard factors, severe accident, emergency situation, radiation accident, emergency situation, stress loads, irradiated fuel assembly of a nuclear reactor, radiation, radioactive contamination, radiation dose, radiation safety, risk, probabilistic NPP safety analysis, uncertainty, modern computing technologies, software, risk management.

Disasters and society

In the modern highly industrialized world, the increase in damage from major accidents and disasters of a man-made and natural nature creates a real threat to the economy of not only individual regions, but also the planet as a whole. The catastrophic consequences of exposure to damaging factors in emergency situations (ES) are one of the key global problems of humanity. In the second half of the twentieth century, the number of extreme natural events increased by 6 times per decade, and the average annual volume of economic losses by more than 10 times (Fig. 1).

The safety of nuclear energy goes beyond national borders; it is becoming an issue for the entire world community. The very existence of human civilization is being held hostage to the trouble-free operation of nuclear technologies. Major accidents are a reality of human existence. Accidents, incidents and disasters in the modern world at nuclear and radiation hazardous facilities (NRHF) are, unfortunately, not so rare (Table 1).

The accidents at Three Mile Island, Chernobyl and Fukushima showed that the safety of nuclear power is still a problem waiting to be solved. Radiation rain can suddenly fall on a person's head, no matter where he is. This fact leaves a special imprint on the discussion of the safety of nuclear energy and the responsibility of scientists, engineers and politicians for this safety. Any new accident at a nuclear power plant increases tension and reasons for the formation of negative public opinion in connection with technological risk. Faith in progress reaches its limits and turns into distrust of the main scientific and technical institutions.

If one or more major radiation accidents occur, it cannot be ruled out that the public will no longer consider the use of nuclear energy acceptable.

No debate about risks and dangers social development today they cannot do without the involvement of science, since only through its participation is it possible to discover the existence and scale of threats. At the same time, science is in close connection with high-tech nuclear technologies, which in fact are a significant cause of the emergence of man-made risks and dangers that have not previously existed in society in this form, the global harm from which represents a new level of threat to civilization due to the intensive development of technology .

The problem of proliferation of sensitive nuclear technologies and materials has become a major security threat, classified as one of the main global problems. The “production” of risks by science and technology itself and with their participation - in fact, this is what is new in the issue of risks: science and technology, in the conditions of innovative development of nuclear technologies and production, must deal with the consequences of their own activities. Reducing threats in this direction required the adoption of unique measures by the leaders of the USSR, Russia and the USA. This joint work has no precedent in the scope of the problems solved and the quality of execution, which made it possible to minimize the consequences of major radiation disasters that occurred.

Solving any complex problems, including those of global nuclear safety, is carried out, as a rule, under conditions of significant uncertainty and is impossible without the use of modern computing technologies, a brief summary of which is the focus of this article.

It is best to begin a review of the consequences of major accidents and catastrophes for the sustainability of economic objects of regions and countries in emergencies by trying to determine what these phenomena are.

We view a disaster as a serious, relatively sudden, often unexpected destruction of the normal structure of a socio-economic system or subsystem (depending on a force, natural or social, internal to the system or external to it), which the system cannot control in any way. This is an event concentrated in time and space, in which the entire society or a relatively independent part of it is exposed to serious danger and suffers losses, leading to disruption of the socio-economic structure and disruption of the performance of all or some of the vital functions of the existence of society.

The World Bank defines a disaster as “an extraordinary event of limited duration (war or civil unrest) or natural disaster (earthquakes, floods, hurricanes) that seriously affects a country's economy.” The US Federal Disaster Management Agency defines a disaster as “an event that causes destruction of a magnitude causing loss of life that cannot be controlled through normal operations.” The real meaning of such a catastrophe is that it creates problems in the given specific situation problems that cannot be solved using the national resources available in a given region (country).

Typical examples of the world's largest man-made and natural disasters that have had a noticeable impact on the economy of the most developed countries of the world and the fate of millions of people in the world, Ukraine, Belarus and Russia are the radiation accident at Unit IV of the Chernobyl Nuclear Power Plant in the former USSR and the destructive consequences of natural factors (9- a major earthquake and a 10-meter tsunami wave that flooded more than 320 km2 of land) and a major man-made radiation accident at the Japanese Fukushima-1 nuclear power plant. These events called into question the concept of defense in depth as a way to prevent operational risks.

The main causes of major accidents and disasters (Table 2, 3):

• neglect to ensure nuclear and radiation safety (NRS);
• incorrect actions (personnel errors);
• design flaws, as well as existing technologies and designs of nuclear power plants (NPP);
• imperfection of the scientific and methodological base and software and hardware;
• imperfection (absence) of the state (international) system for operational management of radiation risks.

Catastrophic consequences of the Chernobyl accident

The Chernobyl accident was the result of an uncontrolled chain reaction using prompt neutrons, which resulted in a devastating thermal explosion of the reactor. This happened due to gross violations of operating regulations and design errors (flaws in the design of the control and protection system rods combined with unsatisfactory physical characteristics of the reactor).

More than 26 years later, many lessons have been learned from the Chernobyl disaster. The radioecological and medical consequences of the Chernobyl disaster are discussed in detail in numerous domestic and foreign publications.

The disaster that occurred then - an exceptional example of professional negligence - could hardly have become more serious if people had deliberately conspired to organize this most terrible tragedy in nuclear history. The accident is assessed as the largest of its kind in the entire history of nuclear energy, both in terms of the number of dead and injured people, and in terms of economic damage.

Unlike the bombings of Hiroshima and Nagasaki, the explosion resembled a very powerful “dirty bomb” - the main damaging factor was radioactive contamination. While inferior to the Hiroshima explosion by more than five orders of magnitude in the energy of mechanical destruction, the Chernobyl accident exceeds it by more than two orders of magnitude in radioactive contamination by long-lived radionuclides.

The Chernobyl accident became an event of great social and political significance for the USSR. The painful range of socio-economic consequences associated with the population caught in the radiation impact zone of the accident accelerated the collapse of the USSR and gave rise to a systemic crisis that affected all spheres of society. The systemic consequences of the accident (both in relation to the affected population and the country as a whole) came to the fore in relation to the direct causes of the accident.

The social consequences of the Chernobyl accident are known: the suspension of the rapid development of nuclear energy (a fundamental sector of the economy) in Russia, a sharp increase in opposition to such development in a number of other countries with the adoption of political decisions to curtail nuclear energy.

The main lesson that experts learned: no matter how incredible efforts are made to implement the latest and most advanced technological systems, they will be managed by a person, and unless the level of his responsibility and organization begins to grow in proportions corresponding to new technologies, one cannot be sure of safety and reliability nuclear energy. The power unit is controlled by a person, and the reliability and safety of the station depend on the properties of this person. You cannot rely on technology, no matter how reliable it may seem.

Since then, nuclear power has made significant improvements in all aspects of nuclear power plant safety, in particular in the area of ​​human factors, eliminating the possibility of such disasters.

Man as a source of potential danger

The problem of human factor at nuclear facilities is of exceptional importance for ensuring safety. Many years of experience in operating nuclear and hazardous waste facilities shows that the occurrence of most accidents and incidents is related to the behavior of people, their attitude to their duties and ensuring safety. Thus, according to some estimates, when ensuring radiation safety, the causes of more than 80% of accidents and man-made disasters are personnel errors, which is presented in the diagram (Rostechnadzor statistics).

Ignorance of the causes does not allow us to build a well-founded program aimed at eliminating them. According to INPO, the contribution to personnel errors from errors and vagueness in instructions, regulations and other documentation is 43%, lack of knowledge and professional training - 18%, staff deviations from regulations and instructions - 16%, incorrect work planning - 10%, ineffective communication between station employees - 6%, other reasons - 7%.

Research has shown that erroneous actions or inactions of operators in complex and critical situations have a definite connection with the state of the human nervous system. As A. Einstein rightly noted: “man is a nervous machine controlled by temperament.” Some of the risks are clearly human in nature.

Being at the epicenter of various influences, a person receives a huge number of signals. Some of them are not perceived by mental systems due to weak signals due to the fact that they go beyond the limits of perception, some are processed at an unconscious and subconscious level without involving the structures of consciousness itself (simple signals), and only some of the signals are perceived with the participation of consciousness. The main point brought by consciousness into the general chain of cause and effect is multivariance (in the apt expression of R. Bellman, “the curse of dimensionality”) and the uncertainty of the decision-making process.

The processes of perception of external stimuli and the reaction of the psyche to this information are subject to statistical laws, that is, they have a spread in relation to what is considered correct (normal). This pattern follows from objective statistical laws and does not depend on humans. The probability of a wrong decision always exists, and in the case of mental processes itself, it is also very high. This is due to the objectively existing difficulties of mental, biological and physiological processes. The following problems are associated with human errors: identifying types of errors; correct determination of the probability of error under emergency stress; uncertainty assessment; human errors as a cause of dependent failures; error correlation. Human tendencies toward error and wishful thinking often affect even the most rigorous applications of the scientific method and serve as a major concern in psychology and safety culture. Therefore, from the means and methods for finding solutions, those that allow taking into account the factors of uncertainty, stochasticity, multi-criteria and conflict are selected.

In addition to simple errors (related to oversights), there are errors in the design, construction, manufacture and maintenance of equipment; actions not according to the rules; errors due to incorrect interpretation of the state of the nuclear power plant; erroneous actions at critical moments; control errors, etc.

Severe accidents, complex errors similar to those committed at the Chernobyl nuclear power plant, or management level errors, intentional violations of safety rules
– these rare events do not reflect the psychological mechanisms inherent in actual accidents and can never be quantified.

Automation and computerization do not solve problems because they lead to many dangerous errors associated with software and representing a special category of complex human errors that are difficult to assess.

The disaster at the Japanese Fukushima-1 nuclear power plant in March 2011 is the largest radiation accident in the world after the Chernobyl nuclear power plant. Understanding the causes of what happened and the scale of the consequences of this disaster allows us to draw useful lessons for the future and develop a balanced attitude towards further development nuclear energy.

The accident that occurred on March 11, 2011 at the Japanese Fukushima-1 nuclear power plant was accompanied by loss of primary coolant, overheating and melting of fuel elements, and the formation of hydrogen as a result of the steam-zirconium reaction followed by an explosion explosive mixture which caused fires and radioactive contamination of the environment. An important lesson from this accident was that in order to ensure the safety of nuclear power facilities, one cannot neglect to take into account even such risk factors, the occurrence of which is considered extremely unlikely.

The accident at the Fukushima-1 nuclear power plant, 25 years after the tragic events at the Chernobyl nuclear power plant, became the second warning to humanity about the need to increase safety requirements for nuclear power plants. For the first time, a natural emergency led to a major man-made radiation disaster.

Modern researchers in the field of nuclear energy safety focus on less obvious causes in the initial and subsequent periods of an accident, which is no less important, and explore the question of what preventive measures will help avoid similar disasters in the future. We will also follow this principle when analyzing the initial events at the Fukushima Daiichi Nuclear Power Plant.

1. At the Fukushima-1 nuclear power plant, unlike the Chernobyl accident, there was no nuclear explosion of the reactor. The Fukushima-1 nuclear power plant, designed for a magnitude 7 earthquake, withstood a magnitude 9 earthquake. If it were not for the overlap of other factors (tsunami, problems with backup power supply immediately after the accident), the situation could have been quickly normalized. The subsequent blackout and inability to vent residual heat resulted in significant damage to the containment, reactor cooling systems and spent fuel pools, partial core meltdown, release of radioactive gases, and leakage of contaminated water. 80 thousand people were evacuated from a radioactive contamination zone with a radius of 20 km. Due to the inability to obtain reliable information, the administration was unable to respond to the accident in real time.

2. The miscalculations of the designers and the unwillingness of management and personnel to quickly make decisions in the conditions of parallel developing emergency processes of a severe multifactor accident are alarming (due to the lack of fundamental knowledge among specialists). Decision making went through 12 levels of management between managers and liquidators. The liquidators strictly adhered to pre-written instructions without taking into account the specifics of the accident that occurred.

3. Formally, at the time of the accident, the nuclear power plant personnel had sufficient capabilities to prevent fuel melting. All blocks were earthquake resistant. From a technical point of view, the cause of the fuel meltdown is the untimely replenishment of the reactors with water. The available technical means made it possible, using the internal resources of the nuclear power plant, to ensure heat removal without external water supply for at least 8 hours, during which time the reactor installations could be prepared to receive water from a pre-designated emergency source. The delay in replenishing the reactors with water was 5–6 hours, while the permissible delay was no more than 2–2.5 hours.

4. The reactor installations had multi-barrier protection systems, but were not interconnected from the point of view of eliminating a real emergency accident. The hydrogen explosion in the reactor building of unit No. 1, which affected the course of emergency work and explosions at units No. 2-4, indicates not only the lack of effective systems for suppressing emergency hydrogen, but also the shortcomings of the ventilation systems of the reactor building and the dubious need for its use as a secondary protective shell, which obviously eliminates manual operations when performing emergency measures. It should also be noted that there is no reliable technology for working with irradiated fuel inside the reactor after an accident with damage to standard lifting mechanisms.

5. The situation at Fukushima-1 demonstrated the unpreparedness of Japanese operators for emergency situations. The devil, as we know, is in the details. There are no small details in nuclear energy. In the conditions of a serious accident, time was counted in minutes, but the highly qualified personnel of the station were not ready to work in extreme emergency conditions. The consequences of neglecting to prepare for possible troubles were catastrophic. You can have a very reliable reactor, but stumble on backup power supply sources and cooling water intake systems, on the high vulnerability of spent fuel assembly storage pools, and on insufficient personnel training. The management of the TERCO company, without assessing and realizing in a timely manner the scale of the disaster, and in order to save the face of the company, tried to independently resolve the extreme problem that had arisen, which only aggravated the scale of the disaster.

6. A nuclear power plant is an extremely high-risk facility, designed for many years of operation, more than the life of one generation. Therefore, designers must incorporate solutions into their projects taking into account the safety of future generations. It should be especially noted the shortcomings in the choice of design values ​​of external factors. Due to climate change, sea levels are rising, making nuclear power plants in coastal areas even more vulnerable. There is a need to increase responsibility for making critical engineering decisions in conditions of high seismic activity. During the construction of a nuclear power plant, based on Russian standards safety in nuclear energy, it is necessary to take into account the possibility of a tsunami up to 20 m in tsunami-hazardous areas of Japan. Nuclear power plants must have maximum safety margins, reliability and survivability. Only high-quality materials should be used in their construction. New technologies for protecting high-risk facilities are required.

7. Accidents at nuclear facilities, as a rule, occur suddenly and have severe consequences on a planetary scale. No state alone is able to fully and quickly eliminate the consequences of a nuclear power plant accident. It is necessary to unite the forces and resources of different countries to resolve issues of accident-free operation of nuclear energy facilities. This requires timely submission of reliable information in full, as well as the development of a unified concept for eliminating the consequences of an accident.

8. It is very difficult to objectively predict the course of accidents and resist destructive actions. It is not yet possible to completely eliminate the possibility of accidents at complex technical facilities. Despite heroic efforts, the actions of the nuclear power plant personnel provoked explosions at the nuclear power plant. It was not possible to prevent the melting of fuel in three reactors; radionuclides were released into the environment. Accordingly, it was not possible to avoid the need to evacuate the population. When assessing what happened, it is necessary to take into account the unique extreme conditions, including psychological ones, in which emergency work was carried out. Total destruction, tsunami, disruption of switching connections, radiation, ignorance about the fate of close relatives - all this could not but affect the accuracy and efficiency of personnel actions.

9. The scale and frequency of man-made disasters occurring in the world indicate a significantly increased role of technical specialists. Complex technological systems require strict adherence to technologies and regulations. The quality of training for servicing such systems, as well as eliminating the consequences of accidents, must be raised to a level corresponding to the complexity of objects created in the 21st century.

10. The cause of many major accidents in recent decades is the vicious practice of appointing “universal” managers to senior engineering positions - managers who, due to the lack of appropriate knowledge and experience, are unable to adequately assess the current situation and take responsibility for actions to resolve an emergency situation. Accidents have to be eliminated in emergency situations that require quick decision-making, for which such “managers” are not prepared.

11. To ensure the technical safety of nuclear power plants, it is necessary to introduce backup cooling systems for reactors and their protective vessels, the functioning of which is possible in autonomous mode in the complete absence of main and emergency power supplies. The use of one type of energy during the operation of nuclear power plants is unacceptable. The energy of jet generators can be used as an independent source of energy, including the use of jet pumps to supply water to the reactor core.

12. Inadequate reflection of events occurring as a result of the accident and its subsequent liquidation by official bodies and means mass media(media), did not allow specialists to analyze the situation and provide timely support to quickly eliminate the consequences of the accident. According to media reports, the accident at the Fukushima-1 nuclear power plant outweighs the horrors caused by the ocean wave, although in fact the opposite is true.

13. The explanations provided by the official bodies regarding the reasons for the failure of the emergency reactor cooling system to operate (references to a tsunami that exceeded the design height) are completely incomprehensible. According to official data, 13 diesel generators with fuel tanks were washed away by the wave. But according to the project, diesel generators are located in the basement of the reactor building. If they were washed away, it was not the main ones, but additional mobile diesel generators. It was reported that shortly before the accident, diesel generators at the Fukushima-1 nuclear power plant were replaced by gas generators, which were supplied with gas centrally.

The first days of the accident revealed all the shortcomings of the reactor plant design and the mistakes made by the operating organization. But main mistake The emergency power supply systems and seawater intake systems turned out to be highly vulnerable.

14. Did the plant personnel have a chance to prevent hydrogen explosions at the nuclear power plant? According to the design, when the maximum pressure is exceeded, a safety valve is activated, and steam from the reactor vessel is released into the outer vessel - containment. The containment strength was insufficient, so it was necessary to dump the hydrogen-steam mixture into the reactor building. After modernization in 1992, reactors of this type were required to have a ventilation line to relieve pressure from the torus outside the building. But during the accident, as a result of such ventilation, hydrogen for some reason ended up not outside, but in the premises of the reactor buildings.

Sources and types of risks and uncertainties

The “Fundamentals of State Policy in the Field of Nuclear and Radiation Safety of the Russian Federation for the Period until 2025” pays special attention to the development and implementation of innovative methods, comprehensive analysis tools, forecasting and assessment of the state of nuclear and radiation safety (NRS), identification of risks and their management, as well as scientific and methodological base and software and hardware. Taking into account the duration life cycle and the presence of the threat of severe accidents, the practical safety of the operation of nuclear and radioactive waste is of fundamental importance for assessing the prospects and choosing a strategy for the development of nuclear energy.

Safety determines the future of nuclear energy. By security we mean the state of protection of an individual, society and the environment from excessive danger caused by environmental, man-made and natural factors. Safety management is carried out on the basis of a riskometric analysis of the control object from the perspective of “benefit-damage” and “benefit-harm”.

According to Federal Law No. 184 of December 27, 2002 “On Technical Regulation”, risk is the probability of causing harm to the life or health of citizens, property of individuals or legal entities, state or municipal property, the environment, life or health of animals and plants, taking into account the severity this harm. Radiation risk is the likelihood that a person or his offspring will experience any harmful effect as a result of radiation exposure.

Risk is a multidimensional, multidimensional concept. Risk can be assessed in different ways, so when describing risk, risk uncertainty is referred to. In simple form, the amount of risk is the full cost of expected outcomes or the expected value of an event or action. Total risk is an assessment of the individual risks of individual classes.

An important prerequisite for successful risk analysis and subsequent categorization
is the choice of the concept of risk.

Risk can be viewed in different ways depending on the method and subject of analysis. There are many definitions of risk, born in different situational contexts and different features applications. Differences in definitions of risk depend on the context of the loss, its assessment and measurement. The example of the accident at the Fukushima-1 nuclear power plant shows that risk can be created.

Historically, risk theory is associated with insurance theory and actuarial calculations. Since the 1990s, when the computer network made it possible to take into account a fairly wide range of data, methods for deeper, comprehensive risk prediction have emerged. From the point of view of RUP (Rutional Unified Process), risk is an active developing factor in the process that has the potential to negatively influence the course of the process. A significant contribution to the theory of risk assessment was made during the assessment of radiation and environmental risks, when the theory of “no-threshold risks” triumphed.

Governments different countries make extensive use of sophisticated scientific risk assessment methods for various standards (notably the US Environmental Protection Agency for environmental regulation). Conflicting parties often find themselves faced with a serious conflict of interest. Currently, risk theory is considered as part of crisisology - the science of crises. In crisis situations, many risks arise, varying in content, source of manifestation, magnitude of probability and size of possible losses and negative consequences.

Modern risk research establishes an acceptable formalization of risk for management purposes. Traditionally, the concept of risk in the modern regulatory definition is understood as either the probability of an emergency event at a facility, or very serious possible consequences due to an accident at the facility, or the product of the first and the second. This concept can be applied in cases where the probability of a negative event can be more or less accurately determined, and the damage can be quantified. However, when we are talking about complex negative consequences, only a small part of them can be quantified, and even that, being calculated in monetary terms, can easily be disputed. As for probability, many events may well not be considered probable before they occur.

If the range of consequences and probabilities for different outcomes differ, then the total risk is determined by the sum of their products. This description of risk is satisfied in finance and insurance. The risks here are simple numbers and can be compared. Along with the classical definition of risk in probability theory as a dimensionless quantity, in practice the concept of risk is sometimes used as the amount of risk per unit of time (frequency). The classical concept of risk in this case is the product of frequency and the time under consideration or the lifetime of the object. When the losses are clear and fixed, for example, “human life”, the risk assessment is fixed only on the probability of the event (frequency of the event) and the associated circumstances.

A nuclear power plant, as a complex technological complex, is a source of increased risk; there is a possibility of damage, failure and operational failures with unpredictable consequences. Nuclear energy is one of the few areas human activity, in which predicting the consequences of decisions made, as well as the consequences of the actions of service personnel, is possible only by means of mathematical modeling of a physical experiment.

An example of the creation of full-scale prototypes of nuclear power plants for the purpose of experimental study of their safety and operational characteristics for relatively low-power serial transport reactors for nuclear submarines and surface ships is the work at the A.P. Research Institute. Alexandrova (Sosnovy Bor, Leningrad region). However, even full-scale field experiments on prototypes of transport nuclear power plants did not prevent radiation-hazardous accidents on nuclear ships.

The possibility of full-scale experimental research into the safety of nuclear power plants is limited: it is both expensive and dangerous, and serial production is relative, since there are no two identical nuclear power plants in the world; each is built according to a special design.

A long period of time to identify all the negative effects of nuclear power plants imposes its own uncertainties. The solution is the development of theoretical and computational research methods. The results obtained using computational methods depend on the available experimental data on the properties of the substances used and information on the characteristics of microprocesses within the main process under consideration.

Available experimental data, as a rule, according to metrology and measurement theory, are probabilistic in nature with the uncertainty characteristics accepted for probability theory. The reliability of the results obtained by calculation, in addition to the random values ​​of the input data, also depends on the correctness of the mathematical modeling of the state of the object and the processes occurring in it, as well as on calculation methods in accordance with the capabilities of computer technology. The assumptions made, due to ignorance or the impossibility of solving the problem in a more correct formulation, introduce their own uncertainties into the results. The uncertainty of the results obtained in this case is a task no less difficult than obtaining the results themselves.

The concept of risk reveals a multi-level problem that is already logically complex and cannot be solved by simple means. In particular, low-probability, high-consequence risks should be re-evaluated. Operators will need to develop an improved risk analysis methodology that can adequately deal not only with traditional design failure scenarios, but also with much less likely high-consequence risks.

The safety of nuclear power plants, like any complex and dangerous technical objects, is of a stochastic nature throughout the entire period of operation of the nuclear power plant. The probabilistic safety characteristics of nuclear power plants correspond to the risks associated with accidents and incidents at nuclear power plants and other emergencies caused by internal and external phenomena of natural and man-made origin with immediate and long-term consequences for the population and excess environmental pollution. The accumulation of information on the frequency and numerical value of radioactive emissions during incidents at nuclear power plants makes it possible, within the framework of a developed probabilistic methodology, to clarify the risk of the population from nuclear energy.

In practice, as a rule, regardless of the real nature of the input information, its random nature is assumed, which determines the use of probability theory as the basic theory for expressing uncertainty. To justify the safety of nuclear power plants, probabilistic safety analysis (PSA) has now become widespread, making it possible to regulate safety and justify the necessary technical and organizational measures. To evaluate the results obtained, probabilistic safety criteria (PSC) are used, satisfaction of which means the safety of the nuclear power plant is acceptable.

For the first time, a PSA for technically complex objects was created for the purpose of assessing the risk from nuclear power plants and was carried out in the USA by the group of Professor J. Rasmussen in 1975. The subject of the PSA study is the so-called rare events with possible undesirable consequences. The PSA describes expected and well understood processes. The PSA methodology has acceptable accuracy and practical value if all its limitations are properly met. There is no clear quantitative criterion separating operational events from rare events (eg, frequency of occurrence). This question depends on the current common approach in the state to VKB and requirements for the reliability of the functioning of complex technical objects of various types (see, for example, the general concept of safety - OKB).

The problem of risk assessment in conditions of uncertainty of the state of nuclear power plants occupies a dominant place in common problem decision making. The purpose of risk assessments is to develop recommendations for improving the safety of nuclear power plants (risk management) based on an analysis of the results of risk assessments, including determination of the dominant contribution to it, analysis of the significance, sensitivity and uncertainties of the assessment results. The main contributors to risk can be failure of equipment and safety systems, failure due to common causes and human factors (personnel).

Probabilistic safety analysis (PSA) is inherently aimed at determining the probabilities of development of various processes (scenarios) at a nuclear power plant under specified initiating events. Both the probability of initiating events and the probability of development of the initiated process are the subject of PSA analysis. In parallel, an analysis of the states of the nuclear power plant is carried out, including the specified final state that determines the consequences. The output of the PSA represents the probability distribution function of certain consequences or the numerical characteristics of such a distribution. A characteristic of probabilistic uncertainty is the dispersion of such a distribution or standard deviation, reflecting the average value of possible deviations of the magnitude of consequences from the mathematical expectation. How less attitude variance/expectation, the less uncertainty there is in the possible magnitude of the consequences.

The PSA methodology consists of the following steps:

1. Postulation or selection of initial accident events.
2. Determination of possible paths of accident development (construction of “event trees”).
3. Creation of a data bank on the reliability of systems and elements.
4. Analysis of the reliability of security systems.
5. Taking into account the human factor that determines the reliability of the functioning of nuclear power plant systems.
6. Analysis of physical and chemical processes for all possible paths of accident development.
7. Risk assessment in the accepted interpretation.

To select tools that perform security functions and their technical characteristics a list of initiating events (accidents) with their own properties is created. This list includes events considered probable. All design means aimed at preventing the dangerous consequences of these events are developed on the basis of a set of regulatory requirements to ensure their reliability. Accidents that develop from these events are called design basis accidents.

Beyond design basis accidents (BAA) include initiating events against which safety systems are not provided due to the low probability of such events in the opinion of the developer or due to the impossibility of having reasonable engineering measures to protect against them. Beyond design basis accidents also include the initiating events for design basis accidents, but in which the safety systems do not perform the functions assigned to them due to violations that occurred in them. Not every PAD can lead to serious consequences. A severe accident is considered a PAD with serious consequences.

The probability of a safety system failure, which determines the probability of a BDBA, depends on the reliability of the elements of the existing statistical base used. This circumstance is a fundamental difficulty for the implementation of PSA due to the problems of organizing the collection and processing of reliable statistical information on failures and the correctness of its use in a particular case. For newly created objects with a significantly updated element base, this problem can become dominant in the way of correct use of PSA.

Another fundamental difficulty is obtaining information about the behavior of system parameters under numerous states dictated by event trees, which requires statistical methods and mathematical models, long-term observations to establish stable data series according to the law of large numbers. Carrying out a PSA in the current understanding, when there is no engineering and technical study of all the systems of the facility, is an unrealistic thing. The approximation of possible estimates makes a significant contribution to the uncertainty of the results obtained.

In accordance with modern mathematical concepts, the uncertainty in the analysis of achievement (non-achievement) of given performance criteria can be attributed to one of two main types: random (probabilistic) and fuzzy (theory of possibilities, theory of fuzzy sets, etc.). Traditional approaches to risk management are based on assessing the likely consequences of potential events; they are not entirely suitable for extremely low-probability risks with serious consequences, since even if these events are expected to occur, their consequences do not fall within predictable limits.

The problem is aggravated by this. that PSA often underestimates the size of the uncertainties in the input data. As a result, estimates will be more uncertain than stated. Uncertainty increases if there is a correlation between inputs. When the uncertainty of the input data is large, their significant correlation leads to such a large amount of uncertainty in the results that they become practically meaningless. In the case of the tragic events at the Fukushima-1 nuclear power plant, the “black swan” was not the earthquake and tsunami, which could have been completely foreseen, but their scale and gigantic consequences.

Information about the characteristics of random input data in the form of a probability density function or its numerical characteristics is generated on the basis of relevant statistical data. Since there are no statistical data on reliability and safety for the subsystems of new NPPs being designed, the task arises of adapting the available data for similar subsystems and elements of existing NPPs. The main problem is the lack of completeness of an adequate database. There are no unambiguous criteria for its definition and no uniform documentation about it. A great deal of arbitrariness is introduced when data is isolated for a specific nuclear power plant and when it is combined using different sources. The process of forming the necessary database, along with the available statistical information, is of a strong-willed expert nature. To the probabilistic uncertainty here is added the subjective uncertainty associated with the decisions of experts.

The commonly used PSA methodology is based on independent failures; dependent failures are taken into account at a later stage, and the existing data processing is incomplete. It should be noted that the dependent failure database is particularly small. The relationships between failure rates and initiating events are not sufficiently taken into account. There are no methods or models that allow obtaining reliable results with a sufficiently narrow range of uncertainties. Calculation of the same system various groups analysts can lead to results differing by several orders of magnitude. This is another reason for the large uncertainties of the PSA. Modern estimates give too low a value for probabilistic indicators due to incomplete consideration of only dependent failures, even if all other problems are ignored.

The PSA takes into account only a simple form of human error - oversights. The PSA excludes complex forms of human error, unpredictable physical processes, sabotage, acts of war, and many types of unexpected defects. Many such defects have been reported in the past. They include the following categories: pipeline stresses exceeding permissible values; improper installation of equipment; loss of fire resistance of electrical cable penetrations; errors in electrical networks and control circuits; non-seismic resistant design of instrument panels. In most cases, such defects cannot be included in the PSA, since they are unpredictable and there is no adequate basis for assessing the probabilities of failure.

The results of the PSA are likely to be a risk indicator of limited scope, useful only for limited purposes. Criticism of the use of PSA and, in particular, VKB, considers that the current interpretation of the obtained PSA results is misleading and should be changed. Most nuclear power plants do not comply with the CSCs formulated by the IAEA shortly after the Chernobyl accident. It is impossible to reliably determine whether a given nuclear power plant satisfies the VKB.

Probabilistic methods have proven to be ineffective in cases where uncertainties of a non-random nature play a decisive role. This explains the interest that appeared in the 60-70s of the last century in uncertainty models alternative to probabilistic ones. These include subjective probability, upper and lower probabilities, methods proposed by A. Zadeh, based on the theory of fuzzy sets.

Risk is observed as a set of possibilities with outcomes in fuzzy measures. Uncertainty can be identified with fuzzy measures, in a particular case with probability. In accordance with modern mathematical concepts, measurement uncertainty can be attributed to one of two main types: random (probabilistic) and fuzzy (for example, theory of possibilities).

Our intention is to establish a connection between uncertainty and risk and to seek the possibility of quantification - numerical estimates of uncertainty and risk.

Fuzzy safety analysis is intended to complement and expand the capabilities of traditional methods for assessing reliability, safety and risk, and also serve as a basis for comparing analysis results. However, formalizing risk through uncertainty is extremely difficult, since uncertainty as a category is an even greater abstraction than the concept of risk. The proof is the fact of studying uncertainty in various sciences and disciplines where different identifications of uncertainty cannot be reduced to a single definition. Quantification of risk through uncertainty is achievable in fuzzy possibilities and likelihood measures and the corresponding scales of order and names.

Comparison of results makes sense if these results are presented as a numerical interval of expected values ​​“from - to” with a certain confidence probability. In the absence of a measure of “fuzzy”, “fuzzy security analysis” (for example, in terms of “more - less”, “better - worse”) does not bring new knowledge. “Fuzzy analysis” must include a definition of “measure of fuzziness.”

The basis for quantitative risk assessments is a priori information about the frequency or probability of occurrence of initial events. Obviously, in relation to rare events, the form of the probability density distribution function of the initial events cannot be determined, which practically excludes the possibility of determining the probability density of the resulting event, including using the Monte Carlo method, which requires specifying the probability density function of all initial events.

Studying a situation of uncertainty is associated, first of all, with the desire to reduce risk. Its successful solution is currently impossible without the use of new information technologies, an integral part of which are intelligent information processing tools. Theoretical modeling of risk is possible through comparative qualification of the concept of risk with other concepts associated with it in the relationships of natural language words. These procedures are qualitative assessments, techniques of non-classical logic, called pseudophysical logic for estimating the values ​​of properties of objects. The objective of this approach is to establish a transition from assessment to quantification - assigning numbers to decisions and appropriate actions.

The risk management process involves and prescribes the identification and establishment of everything, all events and factors that have a potential influence and impact on the outcomes of activities and natural phenomena. In search of a formal description of the subject of risk, many separate and identical concepts are used. The most commonly used concepts are consequences and probability. A risk set is a set of risk points and possible events of a decision. A risk point is a combination of an outcome and the frequency probability of an event. The theoretical justification of the subject of risk remains complex and controversial. Risk is the vaguely observable uncertainty of the outcome of a worthwhile activity. In game theory, for example, uncertainty, risk and outcome of events are manifested in fuzzy measures.

There are concepts of risk management: risk management as normative management of resources, and risk management: risk governance as a way of resolving problems involved in risk. These descriptions expand the meaningful understanding of the subject of risk, although they are unclear.

Under traditional information technology refers to information technology based on “hard algorithms”, and new information technology refers to technology based on “soft computing” using the achievements of artificial intelligence. Investment decisions must reflect these new approaches to risk assessment.

The lack of knowledge about the conditions and processes at new nuclear power plants being designed is the main factor in the emergence of uncertainties. The problem of uncertainty is inherent in all complex systems.

The complexity of a nuclear power plant and the accuracy with which it can be described and analyzed using methods mastered by science and technology are in conflict. The structuring and establishment of a large number of elements, their connections and states is fuzzy and blurry. It is well known: the more complex the system, the less chance there is to accurately predict its behavior at numerous points in the phase space of its possible state. The random nature of the values ​​of most input parameters that form the state of the system at the initial moment is transferred to the random nature and uncertainty of the system’s behavior.

The next factor is the lack of our knowledge about the processes occurring in nuclear power plants and the need to use various assumptions and approximations. The first factor determines the use of probability theory as a methodology of random variables and processes. The insufficiency of our knowledge about the conditions and processes at new facilities of a large project is the main factor in the emergence of uncertainties.

In the process of presenting the material, one has to deal with different accents in the interpretation of the concept of uncertainty, which is interpreted rather ambiguously; its meaning depends on the nature of the applied problem being solved. Different directions prioritize one or another component of uncertainty. Typically, the following classes of uncertainty are distinguished: inaccuracy (observation error), ignorance, insufficient information, subjective probability, incompleteness, vagueness (Fig. 3).

Fuzzy uncertainty, that is, uncertainty due to the limitations of our knowledge, belongs to the category of subjective uncertainty, since the analysis of such tasks is based on the opinion of experts on individual stages of the logical chain of reasoning being built.

In the work, uncertainty is structured into three types: objective ontological uncertainty as the unmediated limited existence of the subject; subjective from the point of view of the theory of knowledge, epistemological uncertainty as the degree of reliable scientific knowledge; moral uncertainty as free will, the ability of a person to make a choice of action.

The concepts of uncertainty and risk are different. Probabilistic tools allow us to distinguish them more clearly. Uncertainty is the existence of possibility. Risk is observed as a set of possibilities with outcomes in fuzzy measures.

First of all, risk is an aspect of decisions that are made in the present. Risk is a form of current description of the future in the aspect that a decision can now be made based on one of the possible alternatives regarding risk.

Risks relate to possible, but not yet obvious and largely unthinkable damage caused by certain decisions. This gives rise to erroneous ideas to avoid such decisions, say, not to build a nuclear power plant. But, in essence, any decision can become the starting point for a series of undesirable effects. It is also clear that all calculations of damage and probability are subjective or in accordance with established traditions. Subjective probability is an assumption regarding a certain outcome based on judgment or personal experience evaluator. Different possibilities to operate with the same information explain the wide variation in subjective probabilities (Fig. 4).

Ontological uncertainty is the objective impossibility of decisions and actions that need to be made in the present time due to the indirect limited existence of the subject.

Epistemological uncertainty as the degree of reliable scientific knowledge is a subjective lack of confidence of the subject due to limited knowledge about the existing state, situation and future possible outcomes and consequences of decisions and actions that need to be made in the present time.

Moral uncertainty is a subjective possibilistic measure of the subject’s plausible choices of decisions and actions that need to be made in the present tense, based on free will in the modalities “I want”, “can”, “should”. Uncertainty can be identified with fuzzy measures, in a particular case with probability. This measure in each experiment is mentally multiplied with the value of the given goal.

Usually, to work with inaccurately known quantities, the apparatus of probability theory is used. It is assumed that inaccuracy, regardless of its nature, can be identified with randomness. However, there is now an understanding that it is necessary to distinguish between randomness and vagueness, which is the main source of inaccuracy. Randomness is associated with uncertainty regarding the membership or non-membership of some object to a clear set, while probability theory is used as the basic theory.

The concept of fuzziness refers to classes in which there may be various gradations of the degree of membership, intermediate between complete membership and non-membership of objects in a given class, while the theory of fuzzy sets is used as the basic theory.

In practice, as a rule, risk is a function of both statistical and fuzzy parameters. Due to the difference in theories used to describe these two types of parameters (probability theory and, for example, possibility theory), the task of aggregating them becomes non-trivial. Since the advent of opportunity theory, attempts have been made to precisely define the relationship between probability and opportunity.

The direction of these efforts is determined by the choice of one of two premises. The first assumes that probability and possibility express fundamentally different types of information and uncertainty. As a consequence, it is intended to direct efforts not to the search for possible transformations between the two theories, but to the way in which the information represented by the formalism of probability and possibility is consistent.

To describe uncertainty in complex systems, in particular, the apparatus of the theory of fuzzy sets, the founder of which is L. Zadeh, is widely used. Problems related to the presence of a certain probability distribution obtained from sufficient statistical material (random changes) must be solved using probabilistic methods. Problems characterized by the predominance of fuzzy, qualitative estimates must be solved using fuzzy set theories.

“Incompleteness of information” is a complex and ambiguous category, the study of which leads to the emergence of new theories and methods of information processing. Mathematical theories for formalizing uncertain information include many-valued logic, probability theory, error theory (interval models), theory of interval averages, theory of subjective probabilities, theory of fuzzy sets, theory of fuzzy measures and integrals.

Quite popular is the interpretation of fuzziness as the probability of a fuzzy event, which allows the use of integration of numerical and linguistic information in modern systems for collecting and processing information based on heterogeneous, incomplete, inaccurate, fuzzy data and knowledge, which distinguishes them from existing systems statistical processing of information. It is possible to interpret the initial events as fuzzy events characterized by certain measures, which can be fuzzy measures or their particular
case is a probability measure (Table 4).

“Soft computing” implies tolerance for fuzziness and partial truth of the data used to achieve interpretability, flexibility and low cost solutions and for this purpose uses modern computing technologies (fuzzy systems, neutron networks and genetic algorithms) and the relationships between them.

Neural networks (NN) are mathematical models, as well as their software or hardware implementations, built on the principle of organization and functioning of biological neural networks of nerve cells of a living organism. NS are a system of connected and interacting artificial neurons. NNs are not programmed in the usual sense of the word, but are trained. The ability to learn is one of the main advantages of neural networks over traditional algorithms. During the learning process, the NN is able to identify complex dependencies between input data and output, determining the coefficients of connections between neurons, and also perform generalization.

Genetic algorithms (GA) are adaptive search methods that implement evolutionary calculations based on the genetic processes of biological organisms, which are one of the modern principles for solving optimization problems. GAs use genetic operations (crossing and mutation) and evolutionary operation (selection). In this case, the mechanisms of crossing and mutation implement the search part of the GA, and the selection of the best solutions is carried out using the gradient descent method. After a certain number of operations, the GA converges to the best solution, which is either the optimal or close to the optimal solution. Research in recent years has shown that GAs are the best existing methods for solving multifactor optimization problems.

The advantages of fuzzy models (FM) are described in detail in the review (Fig. 5):

• NMs are universal approximating functions; they can approximate any real function with any given accuracy;
• the creation of NMs is much simpler than the construction of traditional mathematical models, especially in the case of modeling complex, poorly defined models and systems, when there are only qualitative ideas about the dependence between the parameters of the system;
• software implementation of NM is often simpler than traditional models;
• the accuracy of solutions obtained using NM is quite acceptable for most applications;
• dependencies between input and output variables can be expressed linguistically and have a clear verbal interpretation.

Many models included in soft computing technologies are universal, complement each other and are used in various combinations to create hybrid intelligent systems (neuro-fuzzy, neurological, genetic-neuron, fuzzy-genetic or logical-genetic systems); data-driven systems (neural networks, evolutionary computing). Therefore, when creating systems that deal with uncertainty, you need to be clear about which of the constituent parts of soft computing, or which combination of them, is best suited to solve the desired problem. Recently, immunocomputing, based on the use of artificial immune systems, has also begun to be classified as “soft computing”.

Combining the above components provides a mutually reinforcing effect to achieve a low cost solution and greater compliance with reality. These components are used in various combinations or independently to create hybrid intelligent systems (GIS). GIS allows you to use the advantages of traditional artificial intelligence tools, overcoming some of their shortcomings, effectively combining formalized and non-formalized knowledge. To formalize the subject area of ​​fuzzy and hybrid systems, along with the term “soft computing”, another aggregating term is used - “computational intelligence”.

There is a need to update existing risk assessment methodology to include low-probability, high-consequence risks. This will require improvements to current procedures and tools to isolate potential risks from a much larger field of uncertainty, something that has not been done before (Figure 4). Traditional decisions about “known unknowns” must be expanded to also include “unknown unknowns.”

Scenario planning, which includes situations that are not imaginable in themselves, can be a useful tool in changing the way you think about identifying risks and assessing vulnerabilities. Naturally, in solving these problems, industry leaders have to start from impossible assumptions and then explore the possible vulnerabilities that follow from them. Often, when it comes to reconstructing a chain of events, a scenario that was previously considered unthinkable becomes quite plausible, even if unlikely.

Another way to change the approach to understanding future events is through role-playing games and other real-world simulations. These games simulate the complexity of real-life events, where seemingly rational interactions between players or their actions can lead to unpredictable results. Deep exploration of the interdependencies and correlations between different risk factors can also help uncover additional influences and potential systemic implications (Figure 6).

It is impossible to solve the problem of calculating risk through uncertainty without defining a goal. Expedient activity is a prerequisite for the presence of risk. Different risk areas may have different approaches to assessing uncertainties. The choice of one or another indicator depends on the formulation of the problem, as well as on the availability of the necessary information and the ability to carry out analysis in the required volumes.

The task of reducing the risk of any project is determined by government policy in the form of certain targets. Target settings can be, for example, price human life, amount of acceptable risk, opportunities public services to protect the population in case of disasters. On the stage preliminary analysis project, it is necessary to assess the scale of acceptable risk indicators and determine the place of the proposed project in the field of the risk matrix (element of the risk matrix). Then it is necessary to roughly estimate the boundaries of the selected matrix element. Within the chosen boundaries, possible alternatives should be analyzed in search of optimal option and corresponding assessment of uncertainties.

IN last years There has been a radical reform of the safety concept of nuclear power plants at all stages of their use. The IAEA has released updated documents regulating the safety of nuclear power plants. In particular, they formulate requirements that the total frequency of core meltdowns does not exceed 10-5/(reactors per year), and the frequency of exceeding the maximum emissions from containment is at least an order of magnitude lower.

The report of the UN Scientific Committee on the Effects of Atomic Radiation (SCEAR, 2012) presented its definition of radiation risk: long-term exposure to average background radiation (from 2 to 20 mSv/year) could not be associated with an impact on human health due to uncertainties in risk assessment from low doses and insufficient statistics from epidemiological studies; the effect of doses less than 100 mSv/year can be considered when the number of cases is large enough to overcome the threshold of “irreducible statistical uncertainties”. The state should give preference to the area of ​​negligible probability with limited consequences. Without such an analysis of each project at the industry level, it will be impossible to compare them with each other.

One thing is clear: the risk assessment methods traditionally used by nuclear power plant developers must change. Today there is a need to modify the concept of risk, which is difficult to clearly define based on numerous risk studies. With all the differences in mathematical tools used or proposed for use in risk assessments, the most significant is the presence or absence of a priori knowledge about the essence, relationship and quantitative estimates of the probability or normalized possibility of the occurrence of undesirable events.

The bearers of a priori knowledge - experts, when constructing models for quantitative risk assessment, must have a mathematical apparatus that allows them to take into account uncertainties due to incomplete knowledge. At the same time, the mathematical apparatus used should not introduce additional uncertainties associated with the subjective choice of one or another option for aggregating the magnitude of an event and the measure of the possibility of its manifestation, which is what proponents of “fuzzy security analysis” insist on.

The uncertainty of the probability of a given consequence is determined by the probability density functions of the initial event and the probability density functions of the operation of the systems of the object affecting the development of the process, if they have probability-dependent parameters.

The Austrian logician and mathematician Kurt Gödel used the theorem on the incompleteness of formalized arithmetic (the incompleteness of information) to prove that meaningful arithmetic cannot be formalized completely. The important logical and epistemological significance of Gödel’s incompleteness theorem lies in the fact that it revealed the impossibility of complete formalization of human thinking. Being within the framework of a probabilistic closed system (bounded theory), it is impossible to prove using aids theory itself (the so-called second theorem of Gödel) that this theory is indeed consistent. To do this, it is necessary to use stronger methods than those that are permissible in this system. Complete formalization cannot be completed at any specific historical stage in the development of mathematics.

The above considerations are the conditions for conducting risk analysis and categorizing major projects in public policy.

Decision Making: Ability to Manage Risks

The task of establishing the properties of information resources of any object is to transform the data flow into information and knowledge necessary and sufficient for the subject to make decision-making activities. It is impossible to propose any universal decision-making method in the presence of uncertainties for large projects of nuclear power plants under construction.

It will be necessary to use different risk assessment methods and the task of comparing the results obtained from them will arise. The totality of areas of activity affected by a specific project and related scientific disciplines, where there are different levels of our ideas about the essence and interrelation of characteristic processes, does not allow us to identify a unified approach.

The paradox of risk-taking decisions is the attempt to incorporate unknown factors into the decision-making process. Decisions are made on issues on which, in principle, it is impossible to make them. Decisions under conditions of uncertainty about consequences can only be made as part of a social process or as a hypothetical situation.

The concept of accident management is that even after the failure of safety systems, the accident must be managed using other systems for safety purposes and/or safety systems for a purpose other than that originally intended. The goal is to eliminate as much severe core damage as possible, or at least prevent early containment failure.

One large project may involve many objects of the same type or different types with different lifetimes relative to the lifetime of the largest project. Typically, decision-making theory includes: the formation of alternatives and the VKB by which alternatives are evaluated; numerical assignment of criteria values ​​and weighting coefficients characterizing their importance; assessment of alternatives to VKB; selection of alternatives and sensitivity analysis. An alternative is a sequence of actions aimed at solving a specific problem.

The criteria for fuzzy classification can either have a quantitative expression (for example, numerically expressed potential damage in dollars, or an understandable combination of certain parameters, the frequency of accidents with severe damage to the core, etc.), or be fuzzy concepts (for example, when trying to classify objects according to the degree of danger).

Some general principles can be formulated to guide decision making and risk management:

1. Decision-making under conditions of uncertainty and lack of knowledge based on hypothetical considerations becomes a key feature of the political and social process. This situation is relatively new, since there is still no theory that describes it holistically, with the exception of specific techniques and descriptions of situations. In this regard, we must strive not only to rationalize the decision-making process, but also to rationally control their implementation. In the case of high technologies, total control turns out to be almost impossible. The possibility of a catastrophe can only be reduced, but not eliminated, but technical question safety measures becomes a social problem of accepting a possible man-made disaster.

2. The problem of risk involves “irreducible ambivalence.” Risk can be assessed and managed, but never completely eliminated. As Aldes Huxley rightly noted: “facts do not cease to be facts when they are ignored.” The possibility of an accident can only be reduced, but not eliminated. People's desire to reduce uncertainty knows no bounds. An accurate forecast is not possible, but can only highlight some scenarios of technological development, some of which can be realized and others prevented in order to reduce the risk to society and future generations. It is difficult to predict which of these scenarios and how they will be implemented.

3. To determine the effectiveness of large investment projects, development and improvement of interdisciplinary scientific research on the issues of their categorization, it is necessary first of all to determine the effectiveness criteria. The choice of the latter determines the range of scientific and technical problems involved, the scope of application of the proposed methodology, the necessary information and financial resources for its development. An important element in the development of such a methodology is the predicted validity period of the analysis results. All of these factors affect the uncertainty of the analysis results and require the development of appropriate approaches.

4. It is necessary that comparable objects be within the same safety concept; for this it will be necessary to determine the risk indicators by which analysis and categorization are supposed to be carried out. The risk associated with a project is characterized by three factors: the event associated with the risk; probability of risk and consequences of the decision made. First of all, it is necessary to decide what relative risks we are willing to take in the event of failure to achieve our economic goal or the occurrence of emergency events.

Empirical research and the Fukushima Daiichi accident show that increasing efforts to improve radiation safety are failing and are only adding complexity to the overall system and making it more prone to accidents. Technically created risks do not disappear, but are transformed, at best, into various types of uncertainty. People's desire to reduce uncertainty knows no bounds. It is necessary to take into account the costs of achieving the declared risk indicators, which determine economic efficiency. For the safety of a nuclear power plant, possible damage from the consequences should not lead to a violation of the economic state of the state, that is, the relative magnitude of the consequences should be significantly less than unity. The economic efficiency of the project under consideration will not allow increasing safety and reducing risks without restrictions due to the required costs for the construction and operation of the facility.

5. A separate task is to assess the risk of large-scale disasters that occur in the case of cascading failure scenarios at all critically important facilities (CIF), differing in great diversity (in terms of technical complexity, justification of the underlying technical solutions, mastery by personnel, damage in case of accidents or their destruction and other aspects). This diversity indicates that in most cases it is impossible to use one method of risk prediction, so there is a need to use an integrated approach taking into account the available information. The desire to reduce the risks from their impact on humans and the environment to zero is, in principle, impossible and unnecessary. It is necessary to search for optimal solutions between ensuring the safety and quality of human life due to the benefits of using new technologies and the costs of ensuring their acceptable safety.

6. Distinctive feature Large-scale nuclear power plant projects with critical facilities are long project implementation times and the need to construct a large number of air conditioning units with different lifespans. This leads to the need to take into account the risks not from an individual KVO, but from their totality during the implementation of the project, and, secondly, to take into account the aging and degradation of KVO equipment.

7. Due to the fact that both existing approaches (statistical and fuzzy) practical use have common features; both must operate with probability as one of the components of risk. The difference lies in a clear quantitative expression in the first case and in a qualitative designation in the second (“yes - no”, “high - low”, etc.). The absence of most statistical information for new nuclear power plants and the need to make strong-willed expert decisions on the use of available information brings both approaches closer together. Therefore, to make a more informed decision, you should try to use all available tools. Making a final decision based on various partial decisions is a task of a higher order.

8. You cannot make a decision if nothing is known about the object of consideration (complete uncertainty). To make a decision under conditions of uncertainty, it is necessary to imagine the scale (indicators, characteristics) of the available uncertainty on the problem under consideration.

9. Probabilistic risk assessment, used by the industry since 1979 following the accident at Three Mile Island (Pennsylvania, USA), will become even more important to ensure the safety of nuclear reactors in the future. The probabilistic approach, if implemented, allows us to have at the output a probability density function of possible consequences. Uncertainty in this case is characterized by the standard deviation from the mathematical expectation. The criterion for assessing the scale of uncertainty can be the value of the ratio of the standard deviation to the mathematical expectation.

10. It is necessary to analyze the possible discrepancy between the realized and acceptable values. The accepted values ​​of the safety factor cannot completely exclude the possibility of random values ​​of operational parameters exceeding the random values ​​of permissible parameters. This circumstance increases uncertainty in decision making.

11. For the fuzzy approach, risk indicators are assessed using the mathematical apparatus of fuzzy logic. But here we are not dealing with quantitative indicators that reflect reality, but with some qualitative ones, which may take on a quantitative form in the interpretation of the experts involved. It would be possible to construct probability density functions for the input data by interviewing a large number of experts for each possible value of the parameter and, on this basis, obtain the probability density function at the output and estimate the scale of uncertainty.

Conclusion

The nuclear industry's long-term success depends on whether it can incorporate the lessons of low-probability, high-consequence accidents like Fukushima into its planning, and how well it can implement large-scale new projects and modernize existing facilities. For this, the most important methods are smart risk management and high-quality implementation of projects within given budgets and deadlines. The security of stations and the response methods of their owners must improve. It is very likely that the principle of adequate protection will significantly reformat the entire set of regulations and rules.

The cornerstone of nuclear power plant safety should be the “design principle”, which consists of the application of new design methods and improved administrative techniques. The development of these methods is a critical step to reaffirm rights of action in energy production and create new opportunities for the entire nuclear power industry (Figure 7).

The recommendations include more stringent requirements for the design and construction of nuclear power plants (more complex instruments and equipment, reliable backup power sources), which will help ensure their full protection from accidents more critical than at Fukushima-1. Professional groups, technical experts, and nuclear industry support bodies must work together to develop analytical tools and risk assessment methods that can be used by individual plant owners and operators to quantify the likelihood and consequences of specific worst-case scenarios. Technologies developed using this approach must be consistent with the safety culture and operating experience of the nuclear power plant.

Designers and equipment suppliers will have to work closely to develop specifications for components and devices that meet the new requirements. It is necessary to increase the resilience of nuclear power plants and the industry as a whole so that they can withstand any unpredictable events. Nuclear power utilities must do a better job of analyzing operational risks to reassure a growing public concern that similar incidents will not occur in the future and that related investment decisions are economically sound. Successful risk management requires an effective information system for the population.

The ultimate goal of risk management techniques is to develop an industry-wide approach to defining and quantifying the likelihood of a Fukushima-like event occurring that will satisfy any regulatory safety requirements while being cost-effective and easy to implement. To this end, they must take a broader approach to defining operational risk and its negative consequences at both the plant and industry levels.

It is necessary to provide measures to prevent accidents and emergency response measures to them and, first of all, to protect the population. Secondly, certain efforts will be required in the field of project management and implementation of a new generation of nuclear power plants. Both of these tasks require a higher level of transparency in decisions made in the nuclear industry. In addition, more attention needs to be paid to project management in critical conditions. Because the concept of reasonable assurance and adequate protection does not involve a direct cost-benefit analysis, any departure from the above objectives and requirements could harm the future of nuclear power.

Naturally, the changed conditions will affect investment priorities regarding the planned modernization and increase in the capacity of nuclear power plant units under construction. In this regard, it can be considered fortunate that the renaissance of nuclear energy, the economic revival of the nuclear industry, is starting slowly. There is time to develop specific mobilization and construction activities and to improve the quality of project planning and implementation of new generation technologies and techniques (such as modular construction and simplified reactor designs, clearly defined methods and well-designed management systems) that allow for more effective returns investments.

The revival of nuclear energy, which has already been mentioned more than once, will not begin until all parties strictly fulfill their obligations in the implementation of each project. This provides the political capital needed to engage in the upcoming debate about the future role of nuclear energy.

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“I would especially like to dwell on the accident at the Chernobyl nuclear power plant. Too many humiliating lies have been written and said about this accident.

Why did the Chernobyl nuclear power plant explode?

There is a lot of literature telling that Chernobyl is a planned and conscious sabotage of the era. But it’s difficult to say anything definite about this. Here the investigation should have its say. However, there is no doubt that it was a man-made disaster. Let's assume that this was an unconscious action. So to speak, we made a mistake. Therefore, let us note an important circumstance: the disaster at the Chernobyl nuclear power plant is not related to design flaws nuclear power plant, but is associated exclusively with incorrect actions of personnel. Of course, today everything is said the other way around. They say that the Chernobyl nuclear power plant was initially flawed, but Fukushima is the height of technological perfection. The Japanese operator in Fukushima just made a mistake. What is not surprising is that these are the laws of the ideological war unleashed against us and going in full swing, regardless of whether we understand it or not. But first things first. Let’s just pay attention to the key circumstances of the Chernobyl accident. The protection has been disabled. An experiment was conducted at the Chernobyl Nuclear Power Plant during which the reactor protection was turned off. There would be no need to write further. So, let me emphasize once again, the protection was turned off; if the protection was turned on, nothing would have happened. At the very beginning of the regulations for that experiment it is written: “Turn off the emergency cooling system of the reactor - the ECCS system.” But it is she who automatically turns on the emergency protection system. Moreover, all the valves were closed, making it impossible to turn on the protection system. Twelve times the experimental regulations violate our NPP operating instructions. Under the cover of night. The most important experiment was carried out at night. Then they repeatedly said that the sleepy staff was unable to adequately assess the situation. And he made one mistake after another. The explosion occurred at 1 o'clock. 23 min. nights. Uncontrolled experiment. The experiment was carried out in such a way that no one who understood the essence of the issue could prevent the targeted destruction of the reactor. The experiment was carried out without the control of the reactor designers. When they were subsequently shown a map of the experiment, their hair stood on end. When concluding an agreement to carry out work in Chernobyl, even the chief engineer of the nuclear power plant, a physicist who understood the essence of the issue, was not involved in this matter. The management of the Chernobyl nuclear power plant, bypassing the specialized institute, instructed Donenergo, an organization that had never dealt with nuclear power plants. The experimental regulations were drawn up and sent for consultation and testing to the Gidroproekt Institute named after. Zhuk, whose employees had some experience working with nuclear power plants. But they did not approve this project and refused to approve it. Despite this, the experiment at the Chernobyl nuclear power plant began. According to the point of view of the commission that investigated the causes of the accident, it was established that gross violations of the rules of operation of the nuclear power plant committed by its personnel are as follows: carrying out the experiment “at any cost,” despite the change in the state of the reactor; decommissioning of serviceable technological protections that would simply stop the reactor before it enters a dangerous mode; hushing up the scale of the accident in the first days by the leadership of the Chernobyl nuclear power plant. However, since 1991, we have been constantly misled by talk of some design flaws.

How the Chernobyl accident was liquidated.

There were no huge casualties. Directly during the explosion at the fourth power unit, only one person died, another died in the morning from his injuries. On April 27, 104 victims were evacuated to Moscow Hospital No. 6. Subsequently, 134 Chernobyl NPP employees, members of fire and rescue teams developed radiation sickness, 28 of them died over the next few months. Yes, there were also liquidators. For example, the father of my classmate. He lives and does not suffer from Chernobyl diseases. God bless him, as well as all the liquidators. In this regard, if we compare, for example, with Bhopal - an accident at a chemical plant in India in December 1984 with the release of poisonous gas, where up to 18 thousand people died - we can say that we escaped with few casualties. Everyone worked harmoniously. The disaster was quickly eliminated. The next day, in just 2 hours 30 minutes, the entire city was evacuated - 44 thousand 600 people. And on the same day, people were placed in pioneer camps, dispensaries, sanatoriums, hotels, creating normal, quite comfortable conditions for them. Now let’s compare the Chernobyl accident with Fukushima. How they treat us. Today we can already say that Fukushima is evidence of technological backwardness. Why? Because Japan has not yet learned how to either produce or service complex technological objects. Cameras, cars - that's welcome. And it’s better not to trust them with nuclear power plants. True, they have the opposite opinion. Here, for example, are the headlines of Japanese newspapers during the Chernobyl disaster. Savages should not be allowed near nuclear technology! A scenario similar to Chernobyl is impossible in Japan in principle! The communist dictatorship is lying about the situation in Chernobyl! Millions of slaves, with the help of the KGB, are driven to eliminate the accident using machine guns! Half of the USSR has turned into a radioactive desert! Today in Russia they say that it is a fake. Truly, the Russians are capable of justifying anyone, even those who are at war with us (Japan refuses to sign a peace treaty with Russia and is formally at war with us) and constantly spoils things for us. I haven’t read these newspapers myself, but I’m sure that’s how they portrayed us in Japan. Because today I watched a Japanese video for children. The wild and dirty Chernobyl boy described everything around him, while the civilized Japanese one was in diapers. This is how the image of Russians is formed from childhood.

Fukushima is evidence of technological backwardness.

So, some advice to the arrogant Japanese who for some reason imagine that they know how to use nuclear technology. It is wrong to build a station near water in a dangerous tsunami-prone area. Considering that the terrain rises, removing the station from any possible tsunami wave would not pose any problems. But the Japanese placed it right on the coastline. It is impossible to build stations without a passive safety system. 40 years ago such systems did not exist, but then all stations were required to install them - it is not that expensive. But the greed of the private operator company defeated common sense. They managed to design Fukushima so that it was designed to withstand a magnitude 8 earthquake, but placed it on a power line designed for a magnitude 6 earthquake! And as a result of the earthquake, the power supply to the station completely stopped. No electricity - no cooling. The station was designed by the Americans (General Electric) in such a way that it could stand completely calmly for a day without cooling. But during these 24 hours it was necessary to supply electricity to the station at any cost. If this had happened in the USSR, they would have gotten a cable somewhere, found something that would provide electricity, and launched it! The Japanese did absolutely nothing. In general, building a nuclear power plant in a seismic zone, on the coastline, closer to the tsunami, is the height of myopia. After all, earthquakes are not uncommon here. Therefore, it is not surprising that the disaster occurred; it is surprising that the disaster did not occur earlier.

The Japanese as liquidators.

Now about what kind of liquidators the Japanese are. Figuratively speaking, the Japanese boys recorded the entire ocean. Hundreds of tons of radioactive water are released into the ocean. And we don’t need to think about collecting money on the Internet for Japan, but preparing claims for damage. This will be especially true when in Kamchatka the river will go radioactive salmon to spawn. In fact, it is not even clear what the Japanese will do next. So far they are only apologizing, but there are no plans. Evacuating people is one thing, but where to place them is another matter. Look at Japan: people are housed in stadiums, lying on the floor in gyms, in unsanitary conditions. Organization - zero. The food is all gone, there is no gasoline, anyone can approach the nuclear power plant in the exclusion zone. No cordon. It was impossible to imagine this in the USSR. And, of course, the famous Japanese kindness. People injured in a nuclear disaster are not admitted to hospitals and are not given housing. They are afraid of radiation. As for the secrecy of information, there is much more of it in an “open” society—Japan—than in a “closed” society—the USSR. I don't want to gloat, but the modern world is cruel. The West ideologically squeezed everything out of the Chernobyl accident. And we must respond in kind. The world respects not the kind, but those who defend their interests every hour. Moreover, in reality today Fukushima is already comparable to Chernobyl. But judging by how the consequences of this accident are being eliminated, there will be much more problems. However, what surprises me most is the reaction of Russian experts. Instead of objectively assessing the situation, they constantly shield the Japanese. When the Japanese raised the level of their disaster to the maximum 7th level, as in Chernobyl, everyone was indignant: they say that the Japanese disaster is not as destructive as the Chernobyl one. Let's be honest. Everything is simple here: it exploded here - the Americans have more contracts for the supply of reactors, the disaster at American reactors means more contracts for our manufacturers. Even a child can understand this. Here are articles published in the USA: they say that the reactors are good, but the Japanese are not mature enough. This is understandable: Americans look after their economic interests. But whose interests are Russian experts looking after?”