The accident at the Chernobyl nuclear power plant. Chernobyl accident

04/26/1986 at the Chernobyl nuclear power plant, in the 4th power unit, an explosion of enormous force occurred, as a result of which the nuclear reactor was completely destroyed. This sad event forever entered the history of mankind as the "accident of the century."

Explosion at the Chernobyl nuclear power plant. 1986, April 26 - black date in history

The most powerful nuclear power plant in the USSR was the source of the release of extremely dangerous pollutants into the environment, due to which 31 people died within the first 3 months, and the number of deaths over the next 15 years exceeded 80. The most severe consequences of radiation sickness were recorded in 134 people due to powerful radioactive contamination. A terrible "cocktail" consisted of a large list of elements of the periodic table, such as plutonium, cesium, uranium, iodine, strontium. Deadly substances mixed with radioactive dust covered a huge territory with a mud plume: the European part of the Soviet Union, eastern part Europe and Scandinavia. Belarus has suffered greatly from the contaminated precipitation. The explosion of the Chernobyl nuclear power plant has been compared to the nuclear bombings of Hiroshima and Nagasaki.

How the explosion took place

During the investigation, numerous commissions analyzed this event more than once, trying to find out what exactly caused the disaster and how it happened. However, there is no consensus on this matter. A force capable of destroying all living things in its path burst out from the 4th power unit. The accident was classified: the Soviet media for the first days kept a deathly silence, but the explosion at the Chernobyl nuclear power plant (year 1986) was recorded abroad by a colossal radiation leak and raised the alarm. It became impossible to keep silent about the accident. The energy of the peaceful atom was called upon to move civilization forward, towards progress, but it changed its trajectory and caused the invisible war of man against radiation.

An explosion began at the Chernobyl nuclear power plant, the date of which will be remembered by mankind for centuries, with a fire in power unit No. 4, the signal of which was received at the control panel at 1.24 am. The fire brigade quickly proceeded to extinguish, having successfully coped with the fire by 6 o'clock in the morning, due to which the fire could not spread to Unit 3. At that time, the radiation level on the territory of the power unit halls and near the station was unknown to anyone. What happened during these hours and minutes with the atomic reactor itself was also unknown.

Reasons and official versions

Analyzing the explosion at the Chernobyl nuclear power plant, the reasons for which at first glance were inexplicable, experts put forward many versions. Summing up the results of the investigation, the scientists settled on several options:

1. Disruption and disruption of the operation of circular pumps due to cavitation (the formation of a shock wave as a result of a chemical reaction) and, as a consequence, a pipeline rupture.
2. Power jump inside the reactor.
3. Low level of security in the enterprise - INSAG version.
4. Emergency acceleration - after pressing the "AZ-5" button.

The latest version, according to many experts in the industry, is the most plausible. In their opinion, the control and protection rods were activated by active work precisely by pressing this ill-fated button, which led to an emergency acceleration of the reactor.

This course of events is completely refuted by experts from the Gospromatomnadzor commission. The employees put forward their versions of the causes of the tragedy back in 1986, insisting that the positive reactivity was caused by the triggered emergency protection, which was the reason for the explosion of the Chernobyl nuclear power plant.

Certain technical calculations that prove the cause of the explosion due to cavitation on an anti-aircraft missile system refute other versions. According to the chief designer of the ChNPP, steam at the reactor inlet, as a result of the boiling of the coolant in the air defense system, got into the core and distorted the energy release fields. This happened due to the fact that the temperature of the coolant reached the boiling point during the most dangerous period. Emergency runaway began precisely with active vaporization.

The explosion of the Chernobyl nuclear power plant. Other causes of the tragedy

In addition, opinions were often voiced about such a cause of the explosion as a sabotage action, which was planned by the United States and carefully hidden by the government of the USSR. This version is supported by photographs of an exploded power unit from an American military satellite, which miraculously found itself in the right place exactly when the explosion occurred at the Chernobyl nuclear power plant. It is very difficult to refute or confirm this theory, and therefore this version remains a guess. It remains only to confirm that in 1986, the explosion of the Chernobyl nuclear power plant led to the disabling of secret facilities (over-the-horizon radar Duga-1, Chernobyl-2).

The earthquake that happened at that moment is also called among the causes of the tragedy. Indeed, shortly before the explosion, seismographs recorded a certain shock in the immediate vicinity of the Chernobyl nuclear power plant. It is the vibration that could provoke an accident that the adherents of this version call the cause of the launch of irreversible processes. Strange in this situation is the fact that the neighboring power unit No. 3 for some reason did not suffer in any way and did not receive information about seismic shocks. But tests were not carried out on it ...

The most fantastic reason for the explosion was also put forward - this is a possible ball lightning, formed in the course of bold experiments by scientists. It was she, if you imagine such a course of events, could well disrupt the operating mode in the reactor zone.

The consequences of the tragedy in numbers

At the time of the explosion itself, only 1 person died at the station. The very next morning, another employee died from very serious injuries. However, the worst began later, when another 28 people died literally within a month. They and 106 other employees of the station were at work at the time of the disaster and received the maximum dose of radiation.

Fire extinguishing

To extinguish the fire, when a fire was announced in power unit No. 4 of the Chernobyl NPP, 69 employees were involved in the personnel of the fire department, as well as 14 vehicles. People extinguished the fire, having no idea about the highest level of pollution. The fact is that it was impossible to look at the devices for measuring the radiation background: one was faulty, the second remained out of reach, under the rubble. That is why no one could even imagine the real consequences of the explosion at that time.

The year of death and sorrow

At about 2 am, some firefighters developed the first symptoms of radiation sickness (vomiting, weakness, and an incomparable "nuclear tan" on the body). After first aid, the patients were taken to the city of Pripyat. The next day, 28 people were urgently sent to Moscow (6th radiological hospital). All the efforts of the doctors were in vain: the fire-tamers were so infected that they died within a month. Trees on an area of ​​almost 10 square meters were also killed by the huge release of radioactive substances into the atmosphere during the catastrophe. km. The explosion at the Chernobyl nuclear power plant, the consequences of which were felt not only by the direct participants, but also by the inhabitants of the three republics Soviet Union, forced to take unprecedented safety measures at all similar installations.

The HBO series is, as you'd expect, full of fictional details. For example, it is said that the city council of people's deputies of Pripyat isolated the city so as not to sow panic, and did not give residents the opportunity to escape. In fact, there was no isolation and the evacuation of the inhabitants of Pripyat happened already on April 27: everyone can listen to the announcement of the Pripyat city council about it.

This is quite a common occurrence: the Western film industry is known for funny blunders about our country. Much more interesting is the fact that "Chernobyl" still remains fertile ground for myth-making in Russia itself.

The Chernobyl accident did not happen at all because of an "experiment", as is commonly thought, and not because of mistakes made by the NPP personnel. The cause of the disaster was two design miscalculations in the design of the RBMK-type reactor. Moreover, the most important of these miscalculations was revealed by his designer, and he even sent a letter to the Chernobyl nuclear power plant - but no one paid attention to it.

The catastrophe of April 26, 1986 was hidden from the very beginning by the Soviet state, which naively believed that any information unpleasant for itself could be hidden. But already on April 28 of the same year, it became clear that scientific and technological progress did not allow such an event to be kept secret. On the morning of April 28, one of the employees of the Swedish nuclear power plant Forsmark passed through the frame - and a negligible amount of radioactive dust set off an alarm. The Swedish National Atomic Agency quickly estimated the direction of the wind - and the "arrow" on the map pointed to the USSR. The Swedes threatened Moscow with an appeal to the International Atomic Energy Agency, and only then the USSR was forced to admit the fact of the disaster.

But the cute provincial habit of not washing dirty linen in public does not go away after one unpleasant lesson. That is why the official Soviet reports to the International Atomic Energy Agency - like the testimony of workers in the nuclear industry - were, alas, falsified. This is easy to see from the text of the INSAG-1 (International Nuclear Safety Group) report of 1987 and the Russian-language official publication on which it was based. They stated: "The design of the reactor facility provided for protection against this type of accidents [...], the personnel turned off a number of technical means of protection and violated the most important provisions of the operating regulations in terms of safety." Allegedly, this was the cause of the accident.

Legion media

It was in these reports of 1987 that the word "experiment" was first heard: the NPP personnel allegedly set up an experiment on the operation of the reactor in abnormal conditions. This "experiment" could only be started by turning off the automatic protection - a system of rods that should "jam" the chain reaction in case of problems with cooling. Due to the disabling of this protection by the personnel, an accident allegedly happened.

A simple analogy: imagine that a bus driver with passengers conducts an experiment, how his bus will behave without brakes, and releases the brakes, and then leaves the track. Of course, in such a variant it is difficult to do without sacrifices. The 1987 reports showed staff to be just such a deranged driver. Such a simple and logical explanation had one significant drawback: it is a lie.

The essence of the accident

The fourth power unit of the Chernobyl nuclear power plant that exploded on April 26 was undergoing preventive maintenance - it was subjected to a regular procedure, mandatory for nuclear reactors. In the approved scheme of each such repair for RBMK-type reactors (high-power channel reactors, these are the ones that were at the Chernobyl NPP) there are tests of abnormal operating modes - just to prevent accidents. In such tests, automatic protection was always turned off for the simple reason that otherwise many abnormal operating modes could not be achieved. That is, the first INSAG-1 report called one of the standard checks required for preventive maintenance an "experiment".

Again, a simple analogy. During technical inspection, the engine oil is drained from the car, for which you need to unscrew the drain plug. The fourth power unit of the Chernobyl nuclear power plant was a car on which the personnel, according to the instructions, “twisted the plug” - stopped the protection of the reactor. But if a car with an open traffic jam and draining oil suddenly explodes and kills a lot of people, then no one will ever blame the mechanic. Questions will arise to the one who made the car. Let's try to understand why a planned test event - and not at all a fictional "experiment" - led to an accident.

Wikipedia

From the testimony of Academician Legasov: “From the throat of the reactor, such a white, several hundred meters column of combustion products, apparently graphite, was constantly flowing out. Inside the reactor space, a powerful crimson glow was visible in separate large spots. "

In the heart of the exploded Chernobyl reactor is a cylinder of two thousand tons of graphite, pierced by ~ 1700 channels (pictured below).

Water flows through the channels, slowing down the neutrons from the nuclear fuel to the required "operating" speed, because on too fast, immediate neutrons, the reactor starts to "slow down" automatically. If an accident occurs and the reactor starts to overheat, according to the plan, the water from the channels evaporates. Water vapor slows down neutrons worse than water - that is, when overheating, the reactor must "slow down" itself, protecting itself from a subsequent explosion.

Alas, the designers calculated the scheme inaccurately. They put too much graphite in the reactor. Therefore, even without water, graphite slowed down neutrons enough - when the water in the channels boiled from overheating, the reactor continued to accelerate. Let's continue the car analogy: it's as if the designers of a car got it wrong so that the brake pedal at high speed would work like a gas pedal. This is the first and very big mistake made by the RBMK creators.

The space between the channels is filled with two thousand tons of graphite - pure carbon that ignited after the explosion of the reactor. The use of combustible material to create a reactor is another, albeit less fatal, design mistake.

But, unfortunately, there was also a second mistake - it was it that led to the Chernobyl disaster. When the reactor overheats, emergency protection rods are pushed into it - made of a material that perfectly absorbs neutrons and, due to this, instantly stops the chain reaction. At RBMK, the design of the rods was poorly thought out. They were introduced into channels with water, which slows down neutrons, and displaced water, accelerating the chain reaction of uranium fission. Imagine that your car has an emergency brake that is only pressed when things are really bad and it is about life and death. The Chernobyl nuclear power plant was a machine in which the emergency brake could only additionally add gas.

At 2 am on April 26, the personnel of the Chernobyl NPP did not know that the reactor was self-accelerating and not self-damping - no one informed them about it. But they knew how to read instrument readings. And so they saw that with a decrease in the amount of water in the channels, the reactor power suddenly began to grow, and not fall. Noticing this, the personnel gave the command to insert the emergency rods. And the first few seconds of their input - when the water had already been displaced, and the "damping" parts of the rods had not yet had time to enter - it was enough for the reactor power to jump additionally sharply. Overheating arose, from which part of the reactor channels was deformed and blocked further insertion of the emergency rods. The reactor continued to heat up, an explosion occurred, and then another.

Their capacity was several tons in TNT equivalent - a significant part of the reactor was destroyed, the fission products of uranium were thrown into the atmosphere by an explosion. The catastrophe happened, and the main role in this was played by the miscalculations of those who created the reactor.

Why did they lie?

Legion media

The reasons why the USSR decided to make the people who operated the reactor extreme are not so difficult to understand. Let's say your industry has made a car, which sometimes starts to brake like gas. The driver on it did not know about it and during the "braking" accelerated, which made him enter the crowd of people. Who should be judged for this? It is possible for industry, designers and so on, but this is a bad option: there are a lot of bosses' signatures on pieces of paper about the launch of this type of reactor into a series: ministers, chief designers - in a word, big shots, people with connections.

It is much easier to blame the driver, and in the case of the Chernobyl nuclear power plant, ordinary reactor operators. They have no connections to the very top, they can write off anything, but the Soviet atomprom will be at its best and no one will have to travel from the bright and spacious Moscow office to the Kolyma.

Legion media

And everything would have gone like clockwork - in the Soviet fables about the "experiment" of irresponsible NPP workers in the IAEA they completely believed, because how could they find out the truth, if it had not been for the collapse of the Union. The once omnipotent Soviet ministries and design bureaus suddenly lost their connections at the top, and the top ranks themselves have radically changed.

It was then that completely different information came from the former USSR to the IAEA, on the basis of which the INSAG-7 report was issued. Its main conclusions admit: "The accident occurred as a result of the superposition of the following main factors: the physical characteristics of the reactor, the design features of the regulators, the output of the reactor into an irregular state." Note: the words about the guilt of the staff have disappeared completely. Even the irregular state of the reactor is not attributed to him. Indeed, as shown in the same report, bringing the reactor to an irregular state during scheduled repair was not considered a deviation from the requirements for its operation.

What is the role of lies in the Chernobyl disaster?

To the developers' credit, they recognized the problem earlier than others and even tried to warn about it.

As can be seen from the letters (you can read the full version here), already three years before the accident, the management of the Chernobyl nuclear power plant was warned about the problems with the rods - and about ways to solve them. However, no one reacted in any way to the letter, so great was the belief in the "trouble-free" atomic energy.

However, the above letters - on the last page you can see that the head of the Chernobyl nuclear power plant was among their addressees - had no effect. Not a single witness to the accident remembers being introduced to this letter. This ignorance happened for a very simple reason: in the USSR, before Chernobyl, practically no one knew anything about a series of accidents in the nuclear industry - for example, 1957 at Mayak or 1975 at the Leningrad nuclear power plant, of the same type as the Chernobyl nuclear power plant. The habit of sweeping garbage under the carpet has led to the formation in the country and the world of the idea that nuclear reactors are safe, no matter what you do with them. The meaning of the letter from the designers simply did not reach the director of the Chernobyl NPP: he was sure that there could be nothing super scary from the problems described in the letter.

The problem was peculiar not only to the USSR: in the first half of the 1980s, an article by scientists with a good reputation was not accepted in the international scientific journal Nature only because it spoke of a possible accident at a nuclear power plant.

Legion media

Indicative in this regard is the secret minutes of the meeting of the Central Committee of the CPSU of 07/03/1986, which accidentally fell into open access due to perestroika confusion. In it, Gorbachev personally expressed bewilderment at the total complacency that prevailed in nuclear power before Chernobyl:

“I also remember another thing: an article in Pravda dedicated to the 30th anniversary of the first nuclear power plant. There: "nuclear energy can serve as a safety standard." And Acad. Legasov signed it. And what in fact? Chernobyl burst out, and no one was ready ... The director of the station Bryukhanov was sure that nothing could happen ... Meanwhile, during the 11th five-year period, 104 accidents were at [all] nuclear power plants, for last years there were many [smaller] accidents at the Chernobyl nuclear power plant. This did not alert you ...

We have been hearing from you [scientists, specialists, ministers for 30 years. - A. B.] that everything is here [in nuclear energy. - A. B.] is reliable. And you expect that we will look at you as gods. From this everything also went. Because the ministries and all scientific centers were out of control. It ended in failure. And now I do not see that you think about the conclusions. Most of all, you state the facts, or even try to gloss over some ... A spirit of servility, toadying, grouping, persecution of dissidents reigned throughout the system poisoned the atomic mainstream. - A. B.], window dressing, personal connections and different clans around different leaders. "

Legion media

You can treat MS Gorbachev in different ways, but here his conclusions are very close to what the experts in the field of the “peaceful atom” said. The audio recordings of Academician Legasov (by the way, one of the characters in the HBO series) set out many unpleasant details of how exactly the struggle of clans and personal connections negatively affected the safety of Soviet reactors.

If it were not for the traditional Soviet culture of hushing up failures and overemphasizing achievements, the letter from the chief designer about defects in RBMK (and ways to fix them) would not have passed the mind of the director of the Chernobyl NPP, Bryukhanov. And the disaster would not have happened. Chernobyl happened because of the defectiveness not only of the reactor, but also of the entire system of rubbing in glasses, suppression and distortion of reality, rooted in the late Soviet Union.

Has a lesson been learned?

Today, ten RBMK reactors are operating in Russia, and all of them have zero chances of a repeat of the Chernobyl disaster. The reasons are very simple: both critical shortcomings of the RBMK that exploded in Chernobyl were quickly taken into account and corrected (starting in the summer of 1986). Now the concentration of uranium in the fuel for our RBMKs is increased, due to which the reactor has ceased to be over-slowed down - when overheated, it no longer accelerates, but, on the contrary, slows down itself. A bug in the construction of emergency rods has also been fixed: there is no more water in the channels under them. Therefore, now the emergency brake really gives braking, and not a sudden acceleration of the reactor.

In the nuclear industry, the lesson of Chernobyl has been learned, and thanks to the infiltration of information after the collapse of the USSR, it has been learned quite widely.

Unfortunately, this applies to specialists in nuclear power engineering, but does not apply to public consciousness. It still presents this lesson as an example of the negligence and negligence of nuclear power plant operators.

Chernobyl as a topic comes up only in the great anniversaries of the disaster. Therefore, it is not fashionable to delve into this topic especially, and the old tales about the "experiment" and the insidiously negligent workers of the nuclear power plant are still quite popular.

As a result, society is not aware of the main thing: the accident was the result of the habit of reporting upstairs that everything is fine and wonderful. And over time, people rubbing glasses with their bosses are deprived of even minimal control on the part of this very bosses - and in this situation, any system will eventually go haywire.

THE CHRONOLOGY OF THE CHRONOLOGY OF THE NUCLEAR NIGHT ON APRIL 26, 1986 2019-04-26 11:40 35098

33 years ago, on April 26, 1986, the world was shocked by the largest nuclear disaster in history - the fourth power unit exploded at the Chernobyl nuclear power plant. Many questions about the causes of the emergency and the details of what happened remain unanswered to this day. We propose to trace the chronology of events and try to understand at what moment and why "something went wrong ..."

Due to the fact that, on the orders of Bryukhanov and Fomin, water continued to be poured into the destroyed reactor until 9 am, the firefighters had to pump it out into the cooling pond all day on April 26. The radioactivity of this water did not differ from the radioactivity of the water in the main cooling loop of the reactor during its operation.

The available instruments had a measurement limit of only 1000 micro-roentgens per second (that is, 3.6 roentgens per hour) and went off scale in droves, in connection with which there were suspicions of their serviceability.

Mikhail Lyutov, curator of the nuclear safety department, doubted for a long time that the black substance scattered everywhere was graphite from blocks. Viktor Smagin recalls: "Yes, I see ... But is it graphite? .." Lyutov continued to doubt. This blindness in people has always driven me mad. See only what is beneficial to you. Yes, this is death! - "And what is this ?!" - I already started yelling at the chief. "How many is there?" - Lyutov finally woke up. "

From the debris left after the explosions, people were bombarded with gamma rays with an intensity of about 15 thousand roentgens per hour. The eyelids and throat burned people, the skin of the face was tightened, it took their breath away.

- Anna Ivanovna, dad said that there was an accident at the station ...

- Children, accidents happen quite often. If something serious happened, the city authorities would have warned us. We have a theme: "The Communist Movement in Soviet Literature." Helen, come out to the board ...

This is how the first lesson began on April 26 at the Pripyat school, Valentina Barabanova, a French language teacher, recalls this in her book "On the Other Side of Chernobyl".

The water, which continued to be supplied to the fourth unit of the nuclear power plant, finally ran out.

Anatoly Sitnikov, deputy chief engineer for the operation of the first stage of the Chernobyl nuclear power plant, received a deadly task from Viktor Bryukhanov: to climb onto the roof of block B and look down. Sitnikov carried out the order, as a result of which he saw a completely destroyed reactor, twisted fittings, the remains of concrete walls. In a couple of minutes, Sitnikov took on a huge dose of radiation. Later he was sent to a Moscow hospital, but the transplanted bone marrow did not take root, and the engineer died.

Sitnikov's message that nothing remained of the reactor caused only additional irritation to Viktor Bryukhanov and was not taken into account. Water continued to be poured into the reactor.

In further memoirs, Viktor Smagin describes that walking along the corridor, he felt strong radiation with his whole body. A "spontaneous panicky feeling" appeared in my chest, but Smagin tried to control himself.

“How much to work, guys?” I asked, interrupting their squabble. “The background is one thousand micro-roentgens per second, that is, 3.6 roentgens per hour. Work five hours at the rate of twenty-five rem! " “All this is nonsense,” summed up Samoylenko. Krasnozhon got mad again. - "Well, you have no other radiometers?" I asked. “There is in the locker, but it was overwhelmed by an explosion,” said Krasnozhon. - The authorities did not foresee such an accident ... "

"What are you - not bosses?" - I thought and went on, ”writes Smagin.

- I listened and realized that they were swearing because they could not determine the radiation situation. Samoilenko presses that the radiation is huge, and Krasnozhon - that you can work for five hours at the rate of 25 rem (the biological equivalent of an X-ray is an outdated non-systemic unit of radiation measurement).

“I quickly changed clothes, not knowing yet that I would return from the unit to the medical unit with a strong nuclear tan and a dose of 280 rad. But now I was in a hurry, put on a cotton suit, shoe covers, a cap, "petal-200" and ran along the long corridor of the deaerator stack (common for all four units) towards the control room-4. There is a failure in the "Skala" computer room; water is pouring from the ceiling onto the equipment cabinets. I didn’t know then that the water was highly radioactive. There is no one in the room. Yura Badayev, you see, has already been taken away. I went on. In the room of the dosimetry board, Krasnozhon, deputy chief of the RB service, was already in charge. There was no Gorbachenko. Therefore, they have also taken them away or are walking around the block somewhere. Samoilenko, the head of the night shift of dosimetrists, was also in the room. Krasnozhon and Samoilenko cursed each other, - recalls Viktor Smagin.

“First I went into the empty office of Bryukhanov. I saw complete carelessness. The windows are open. I found people already in Fomin's office (Nikolai Fomin is the chief engineer of the NPP). To the question "What happened?" I was again answered: "The rupture of the steam line." But, looking at Fomin, I realized that everything is more serious. Now I understand that it was cowardice associated with a crime. After all, they already had some kind of real picture, but they honestly did not tell us about the danger. Maybe then some of our employees would not have ended up in the hospital, ”Berdov writes.

A new shift of doctors arrives at the Pripyat hospital. However, the worst victims were sent to the capital's hospitals only in the evening.

“I will say right away that the Pripyat city department of internal affairs did everything possible to exclude radiation damage to people,” recalls Major General Berdov. “The whole city was quickly cordoned off. But we still did not fully orient ourselves in the situation, since the police did not have their own dosimetric service. And from the Chernobyl station they reported that there was a steam-water release. This formulation was considered the official point of view of the management of the nuclear power plant. I drove up there at eight o'clock in the morning. "

In the "glass" (conference hall) Viktor Smagin found overalls, shoe covers, "petals". Smagin realized that since he was asked to change his clothes right in the conference room, it means that there was radiation at ABK-2. Through the glass Smagin saw the Deputy Minister of Internal Affairs of Ukraine Berdov, who was walking into Viktor Bryukhanov's office.

The treated and disguised victims are being brought to the hospital.

“I ran into the street to the bus stop. But the bus didn't fit. Soon a "rafik" was filed, they said that they would not be taken to the second checkpoint, as usual, but to the first block. Everything there was already cordoned off by the police. The ensigns were not allowed to pass. Then I showed my round-the-clock pass to the operational staff, and I was reluctantly, but allowed to pass. Near ABK-1 I met Bryukhanov's deputies Gundar and Tsarenko, who were heading to the bunker. They told me: “Go, Vitya, to the control room-4, replace Babichev. He changed Akimov at six in the morning, he probably already grabbed ... Do not forget to change clothes in the "glass" ... ", - writes Viktor Smagin.

“At the time of the accident, I was passing through Pripyat,” recalls Vladimir Bronnikov, in 1976-1985 - deputy chief engineer of the Chernobyl nuclear power plant. - The first house on the outskirts of the city. I had my family and children with me - they had not yet managed to move to my new place of work. I did not see the explosion. At night I realized that some event had happened - too many cars were driving past the house, in the morning I saw that they were washing the roads. I realized the scale of what had happened only on the night of April 27, when some of the personnel arrived home from the station in the evening and told what had happened. I didn't believe it, I thought they were lying. And on the morning of April 27, I took up the duties of the chief engineer of the station. My task was to localize the accident. It took my group about five days to understand the scale of the incident. "

“I had to change Alexander Akimov at eight in the morning on April 26, 1986. He slept soundly at night, did not hear any explosions. I woke up at seven in the morning and went out to the balcony to smoke, - recalls Viktor Smagin, the shift supervisor of Unit 4. - From the fourteenth floor I can clearly see the nuclear power plant. I looked in that direction and immediately realized that the central hall of my native fourth block was destroyed. Fire and smoke over the block. I realized that it was rubbish.

I rushed to the phone to call the control room, but the connection was already cut off. In order not to leak information. I was about to leave. He ordered his wife to close the windows and doors tightly. Children should not be allowed out of the house. Do not go out on your own either. Stay at home until my return ... "

The staff of the Pripyat hospital was exhausted. Despite the fact that by the morning all the doctors, including surgeons and traumatologists, were involved in receiving the victims, there was not enough strength. “I called the chief medical officer:“ Why aren't patients treated at the station? Why are they being brought here "dirty"? After all, there, at the Chernobyl nuclear power plant, is there a sanitary inspection? ”, - writes Tatyana Marchulaite. After that, there was a half-hour respite.

A special group of the Civil Defense Headquarters arrives at the NPP to check the dosimetric situation. The chief of staff himself went to the other end of the region to conduct "important exercises."

Complete elimination of the fire.

From the explanatory note of the fireman of the third guard V. Prishchepa: “Upon arrival at the nuclear power plant in Chernobyl, the second department put the auto pumps on the hydrant and connected the sleeves to the dry pipes. Our car drove up from the side of the turbine hall. We built a trunk line that led to the roof. We saw - there is the main hearth. But it was necessary to establish the whole situation. Lieutenants Pravik and Kibenok went into reconnaissance ... The boiling bitumen of the roof burned boots, flew in splashes on clothes, and eaten into the skin. Lieutenant Kibenok was where it was more difficult, where it became unbearable for someone. Backing up the fighters, he fastened the ladders, intercepted one or the other trunk. Then, having descended to the ground, he lost consciousness. After a while, when he came to his senses, the first thing he asked was: "How is it?" They answered him: "Extinguished."

“The burnt Shashenok remained in my memory. He was our nurse's husband. The face is so pale and stony. But when consciousness returned to him, he said: “Get away from me. I'm from the reactor, move away. " Surprisingly, he still cared about others in this state. Volodya died in the intensive care unit in the morning. But we have not lost anyone else. Everyone was on IVs, everything that was possible was done, ”recalls one of the employees of the hospital in Pripyat.

In the hospital, Vladimir Shashenok, an adjuster, about whom Anatoly Dyatlov wrote, dies. By this time, 108 people were hospitalized.

“On the morning of the 26th, the director of the forestry enterprise called,” recalled the forester Ivan Nikolaevich. - He calls himself and is silent ... After a while he says: "Listen, Ivan Nikolaevich ... A trouble has occurred ..." And again he is silent ... I am also silent. And to myself I think: "Is it really a war" ?! A minute later, the director finally squeezes out of himself: "There was an accident at the Chernobyl nuclear power plant." Well, I think it's nothing special ... However, the director's anxiety was transmitted to me. Some time later, the director says more decisively: “Immediately withdraw all equipment from this area. Just don't tell me the reason. "

“We saw an impressive view from the broken window of the deaerator stack at the 14th elevation in the area of ​​the eighth turbine: the reactor parts and elements of the graphite stack, its internal parts were randomly scattered throughout the adjacent territory,” says Evgeny Ignatenko, a member of the Emergency Commission of the Ministry of Energy, Doctor of Technical Sciences. - During the inspection of the yard of the nuclear power plant, no more than 1 minute, the readings of my dosimeter reached 10 roentgens. Here, for the first time, I felt the impact of large gamma-ray fields. It is expressed in some kind of pressure on the eyes and in the feeling of a slight whistling in the head, like a draft. These sensations, the dosimeter readings and what I saw in the yard finally convinced me of the reality of what had happened ... In a number of places, the radiation level exceeded one thousand (!) Roentgens. "

“There were many doctors among the victims of the accident that night. After all, they, who arrived at the station from all over the region, took out firefighters, physicists, everyone who was at the station. And their ambulances drove right up to the fourth block ... A few days later we saw these cars. They could not be used, as they were heavily contaminated ... ”, recalls the science journalist Vladimir Gubarev, who arrived at the scene of the accident a few hours after the series of explosions. Impressed by what he saw, he wrote the play "Sarcophagus", which was staged in 56 theaters around the world and was a huge success, especially in Japan. In Great Britain, the play won the Laurence Olivier Theater Award.

Deputy Minister of Internal Affairs of the Ukrainian SSR, Major General of Militia G.V. Berdov, arrives in Pripyat. He took into his own hands the leadership for the maintenance of public order and the organization of the traffic police service. Additional forces were called in from the area.

Firefighters managed to localize the fire.

Only between 4 and 5 o'clock in the morning the heads of the nuclear power plant gradually gathered their forces and phoned the officials. Responsible leaders begin to arrive at the scene of the accident.

A telephone call rang in the apartment of Mikhail Lyutov, the deputy chief engineer of the station for science and the curator of the nuclear safety department. The call, however, was interrupted, and Lyutov himself learned about what had happened at the station.

It was found that the radiation levels in the area adjacent to the destroyed reactor significantly exceed the permissible levels. Firefighters began to be placed five kilometers from the epicenter and introduced into the danger zone in shifts.

An operational group of the Fire Department of the Ministry of Internal Affairs of the Ukrainian SSR under the leadership of Colonel of the Internal Service V.M. Gurin arrived in the area of ​​the accident. He took over the leadership of further actions.

At the scene of the accident, 15 fire departments arrived with their special equipment from various districts of the Kiev region. All were involved in extinguishing the fire and cooling the structures that collapsed after the accident in the reactor compartment.

Checkpoints were created, roads leading to the Chernobyl nuclear power plant were blocked, additional patrol and search service squads were formed.

Senior paramedic Tatyana Marchulaite recalled: “I was surprised that many of those who entered the military. They were firefighters. The face of one was crimson, the other, on the contrary, was white as a wall, many had burned faces and hands; some were chilled. The sight was very difficult. But I had to work. I asked the arrivals to put their documents and valuables on the windowsill. There was no one to rewrite all this as it should be ... From the therapeutic department there was a request that no one should take anything with them, not even a watch - everything, it turns out, had already been exposed to radioactive contamination, as we say - “phonilo” ”.

An operational group of the Fire Department of the Internal Affairs Directorate of the Kiev Regional Executive Committee, headed by Major of the Internal Service V.P. Melnik, arrived at the scene of the accident. He took over the leadership of the fire, called other fire departments to the scene of the accident.

The first shift of those who began to extinguish the fire received high doses of radiation. People began to be sent to the hospital, new forces arrived.

Not everyone was aware of the danger of radioactive radiation. So, an employee of the Kharkov Turbine Plant A.F. Kabanov refused to leave the unit, since there was a vibration measurement laboratory in the machine room, which simultaneously measured the vibration of all bearings, and the computer produced good visual printouts. Kabanov was sorry to lose her.

The senior paramedic of the Pripyat hospital, Tatyana Marchulaite, meets the first victims in the emergency room.

“Petro Palamarchuk, a hefty man, brought in and seated Volodya Shashenok, an engineer at the commissioning plant,” Anatoly Dyatlov writes. - He watched in the room at the twenty-fourth mark for non-standard devices, and scalded him with water and steam. Now Volodya was sitting in a chair and only slightly moved his eyes, no screaming, no groaning. Apparently, the pain exceeded all conceivable boundaries and turned off consciousness. Before that, I saw a stretcher in the corridor, suggested where to get it and carry it to the first-aid post. P. Palamarchuk and N. Gorbachenko took them away. "

The fire on the roof of the reactor compartment was liquidated, and the fire in the room of the main circulation pumps of the fourth power unit was also extinguished.

NPP Director Viktor Bryukhanov could not take any concrete action - his condition looked like a shock. The work of collecting information on radiation levels from the dosimetrists and drawing up the corresponding certificate was undertaken by the secretary of the party committee of the NPP, Sergei Parashin, who arrived at the shelter at about 2 hours 15 minutes.

Those who watched the explosion at the Chernobyl nuclear power plant from afar did not really suspect anything serious. The memories of the night of April 26, 1986 of those who were directly at the station are completely different: “There was a blow. I thought the turbine blades were flying. Then - another blow. Looked at the overlap. It seemed to me that it should fall. We went to inspect Unit 4, saw destruction and glow in the reactor area. Then I noticed that my feet were sliding on some kind of suspension. I thought: isn't it graphite? I also thought that this is the most terrible accident, the possibility of which no one has described. "

Firefighters shot down a fire on the roof of the turbine hall.

“On the evening of April 25, my son asked me to tell him a fairy tale before going to bed. I started talking and did not notice how I fell asleep with the child. And we lived in Pripyat on the 9th floor, and the station was clearly visible from the kitchen window. The wife was still awake and felt some kind of shock at home, like a slight earthquake. I went to the kitchen window and saw above the 4th block first a black cloud, then a blue glow, then a white cloud that rose and covered the moon.

My wife woke me up. We had an overpass in front of the window. And on it one after another - with the alarm on - fire engines and ambulances rushed. But I could not think that something serious had happened. He calmed his wife down and went to bed, ”recalls an eyewitness to the events.

The NPP director Viktor Bryukhanov arrives at the station.

“Despite the night and poor lighting, you can see enough. The roof and two walls of the workshop were gone. In the premises, through the openings of the missing walls, one can see in places streams of water, flashes of short circuits on electrical equipment, and several fires. The room for the gas-cylinder is destroyed, the cylinders are in a state of disrepair. There can be no talk of any access to the valves, V. Perevozchenko is right. There are several hearths on the roof of the third block and the chemical workshop, which are still small. Apparently, the ignition occurred from large fragments of fuel ejected from the core by the explosion, ”Anatoly Dyatlov recalls.

Firefighters fought the fire in canvas uniforms and helmets. They did not know about the radiation threat - information that this was not an ordinary fire began to spread only after a few hours. By morning, firefighters began to lose consciousness, 136 employees and rescuers who were at the station that day received a huge dose of radiation, every fourth died in the first months after the accident.

The Pripyat hospital receives a call from the ambulance dispatch office. They reported that there was a fire at the nuclear power plant, there were burned ones.

“I quickly walked a few more meters along the corridor at the tenth mark, looked out of the window and saw — or rather, did not see, she was not there — the wall of the building. Along the entire height from the seventieth to the twelfth mark, the wall collapsed. What else is not visible in the dark. Further along the corridor, down the stairs and out of the building. I walk slowly around the building of reactors of the fourth, then the third blocks. I look up. There is something to see, but, as they say, my eyes would not be looking ... at such a sight, ”says the book“ Chernobyl. How it was".

The first fire brigade drove to the scene of the explosion.

“Part of the hall's roof collapsed. How many? I don’t know, three hundred meters - four hundred square meters. Plates collapsed and damaged oil and feed lines. Blockages. From the twelfth mark I looked down into the opening, there were feed pumps at the fifth mark. Hot water jets are beating from the damaged pipes in different directions, falling on the electrical equipment. Steam is everywhere. And there are sharp, like a shot, clicks of short circuits in electrical circuits. In the area of ​​the seventh TG, oil caught fire, flowing out of damaged pipes, operators with fire extinguishers ran there and unwound fire hoses. On the roof, through the openings formed, flashes of fire are visible, ”recalls Anatoly Dyatlov, who immediately after the explosion went into the turbine room.

Another four seconds later - an explosion that shook the entire building. Two seconds later, the second explosion. The reactor lid flew up, turned 90 degrees and fell. The walls and ceiling of the reactor hall collapsed. From the reactor flew out a quarter of the graphite there, fragments of red-hot fuel rods. The debris fell onto the roof of the turbine hall and other places, creating about 30 fires.

“At 01 h 23 min 40 s, the button A3 (emergency protection) of the reactor was pressed to shut down the reactor at the end of the operation. This button is used in both emergency and normal situations. The control rods in the amount of 187 pieces went into the core and, according to all the canons, had to interrupt the chain reaction, ”Anatoly Dyatlov recalls.

Three seconds after pressing the reactor silencing button, the control panel begins to receive alarms about the increase in power, the increase in pressure on the primary circuit. The reactor power jumped up sharply.

“At 01 hours 23 minutes 04 seconds, the control system registered the closure of the stop valves supplying steam to the turbine. An experiment on running out the TG has begun, - Anatoly Dyatlov writes. - Until 01 hours 23 minutes 40 seconds, there are no changes to the parameters on the block. The run goes smoothly. The control room (control room) is quiet, no talking. "

The plant personnel are blocking the emergency protection signals of the reactor due to the critically low water level and steam pressure in the separator drums. The report of the International Advisory Group on Nuclear Safety says that in fact this could have happened as early as 00 hours 36 minutes.

The eighth pump is connected.

The seventh is connected to the six running pumps to increase the ballast load.

The thermal power of the reactor reached 200 MW. Recall that for the experiment, the reactor had to operate at a power of 700-1000 MW.

Despite this, the operating reactivity margin (in fact, the degree of reactivity of the reactor) continued to decline, due to which the manual control rods were gradually withdrawn.

The NPP employees gradually increased the thermal power of the reactor, as a result of which it was possible to stabilize it at around 160-200 MW.

“I returned to the control room at 00 hours 35 minutes,” writes in his book “Chernobyl. How it was ”Anatoly Dyatlov, former deputy chief engineer for the operation of the Chernobyl nuclear power plant. - The time was set after according to the diagram of the recording of the reactor power. From the door I saw bent over the reactor control panel, besides the operator L. Toptunov, the unit shift supervisor A. Akimov, and the interns V. Proskuryakov and A. Kudryavtsev. I don't remember, maybe someone else. He walked over and looked at the instruments. Reactor power - 50 ... 70 MW. Akimov said that when switching from LAR to a regulator with side ionization chambers (AR), a power failure of up to 30 MW occurred. Now they are raising the power. This did not in the least excite me and did not alert me. This is by no means an out of the ordinary phenomenon. Allowed to climb further and moved away from the console. "

At this time, there is a transition from a local automatic control system to a general control system. The operator could not keep the reactor power even at the level of 500 MW, and it dropped to 30 MW.

On April 25, 1986, it was planned to shutdown the 4th power unit for scheduled repairs. During such shutdowns, equipment tests are usually carried out, for which the reactor power had to be reduced to 700-1000 MW, which is 22-31% of the total reactor power. About a day before the accident, the reactor's power began to be reduced, and by 13:00 on April 25, it was reduced to about 1600 MW (50% of the full power). At 14.00, the emergency cooling system of the reactor was blocked, which means that during the next hours the reactor was operated with the cooling system turned off. At 2310 hours, the reactor power began to decrease to the planned 700 MW, but then there was a jump, and the power dropped to 500 MW.

REFERENCE:

Chernobyl nuclear power plant named after V.I. Lenin is located in the north of Ukraine, 11 km from the border with Belarus on the banks of the Pripyat River. The site for the NPP was chosen in 1965-1966, and the first stage of the station - the first and second power units - were built in 1970-1977.

In May 1975, a commission was established to launch the first power unit. By the end of 1975, due to a significant delay in the timing of work at the station, round-the-clock work was organized. The act of acceptance of the first power unit into operation was signed on December 14, 1977, and on May 24, 1978, the unit was brought to a capacity of 1000 MW.

In 1980, 1981 and 1983, the second, third and fourth power units were launched. It should be noted that the first accident at the Chernobyl nuclear power plant occurred in 1982. On September 9, after scheduled repairs, the fuel assembly was destroyed and the process channel No. 62-64 ruptured at the reactor of the first power unit. As a result, a significant amount of radioactive substances was thrown into the reactor space. There is still no consensus among experts about the causes of that accident.

Based on the analysis of old and new data, a realistic version of the causes of the Chernobyl accident has been developed. In contrast to the earlier official versions, the new version provides a natural explanation for the actual accident process and many circumstances preceding the moment of the accident, which have not yet found a natural explanation.

1. Causes of the Chernobyl accident. The final choice between the two versions

1.1. Two points of view

There are many different explanations for the causes of the Chernobyl accident. There are already over 110 of them. And there are only two scientifically reasonable ones. The first of them appeared in August 1986/1 / Its essence boils down to the fact that on the night of April 26, 1986, the personnel of the 4th unit of the ChNPP in the process of preparing and conducting purely electrical tests 6 times grossly violated the Regulations, i.e. ... rules for the safe operation of the reactor. Moreover, for the sixth time, it was so rude that it could not be more rude - removed from its core at least 204 control rods out of 211 standard ones, i.e. more than 96%. While the Regulations demanded from them: "When the operational reactivity margin is reduced to 15 rods, the reactor must be immediately shut down" / 2, p. 52 /. And before that, they deliberately disabled almost all emergency protection. Then, as the Regulations demanded from them: "11.1.8. In all cases, it is prohibited to interfere with the operation of protections, automatics and interlocks, except in cases of their malfunction ..." / 2, p. 81 /. As a result of these actions, the reactor fell into an uncontrollable state, and at some point an uncontrolled chain reaction, which ended in a thermal explosion of the reactor. In / 1 / also noted "negligence in the management of the reactor facility", insufficient understanding of "personnel of the peculiarities of technological processes in a nuclear reactor" and the loss of personnel "sense of danger".

In addition, some design features of the RBMK reactor were indicated, which "helped" the personnel to bring major accident to the size of a disaster. In particular, "The developers of the reactor facility did not envisage the creation of protective safety systems capable of preventing an accident in the event of a set of deliberate shutdowns of technical protection equipment and violations of the operating procedure, since they considered such a combination of events to be impossible." And one cannot but agree with the developers, because deliberately "disconnecting" and "violating" means digging your own grave. Who will go for it? And in conclusion, it is concluded that "the primary cause of the accident was an extremely unlikely combination of violations of the order and operation mode, committed by the personnel of the power unit" / 1 /.

In 1991, the second state commission, formed by Gosatomnadzor and consisting mainly of operators, gave another explanation of the causes of the Chernobyl accident / 3 /. Its essence boiled down to the fact that the reactor of the 4th block has some "design flaws" that "helped" the duty shift to bring the reactor to explosion. The main ones are usually the positive coefficient of reactivity for steam and the presence of long (up to 1 m) graphite water displacers at the ends of the control rods. The latter absorb neutrons worse than water, therefore, their simultaneous introduction into the core after pressing the AZ-5 button, displacing water from the CPS channels, introduced such additional positive reactivity that the remaining 6-8 control rods could no longer compensate for it. An uncontrollable chain reaction began in the reactor, which led to a thermal explosion.

In this case, the initial event of the accident is considered to be the pressing of the AZ-5 button, which caused the downward movement of the rods. The displacement of water from the lower sections of the CPS channels led to an increase in the neutron flux in the lower part of the core. Local thermal loads on fuel assemblies have reached values ​​exceeding the limits of their mechanical strength. The rupture of several zirconium shells of the fuel assemblies led to the partial separation of the upper protective plate of the reactor from the shell. This resulted in a massive rupture of the technological channels and jamming of all control rods, which by this time had passed about half the way to the lower limit switches.

Consequently, the scientists and designers who created and designed such a reactor and graphite displacers are to blame for the accident, and the duty personnel have nothing to do with it.

In 1996, the third state commission, in which the operators also set the tone, having analyzed the accumulated materials, confirmed the conclusions of the second commission.

1.2. Equilibrium of opinions

The years passed. Both sides remained unconvinced. As a result, a strange situation arose when three official state commissions, which included people who were authoritative in their field, studied, in fact, the same emergency materials, and came to diametrically opposite conclusions. It was felt that there was something wrong, either in the materials themselves, or in the work of the commissions. Moreover, in the materials of the commissions themselves, a number of important points were not proven, but simply declared. Probably, therefore, no one side could indisputably prove their case.

The very relationship of guilt between the staff and the designers remained unclear, in particular, due to the fact that during the tests by the staff "only those parameters were recorded that were important from the point of view of analyzing the results of the tests being carried out" / 4 /. So they later explained. This was a strange explanation, because even some of the main parameters of the reactor, which are always and continuously measured, were not recorded. For example, reactivity. "Therefore, the process of the accident development was restored by calculation on the mathematical model of the power unit using not only the DREG program printouts, but also the instrument readings and the results of personnel interviews" / 4 /.

Such a long existence of contradictions between scientists and operators raised the question of an objective study of all the materials accumulated over 16 years related to the Chernobyl accident. From the very beginning it seemed that this should be done on the principles adopted by the National Academy of Sciences of Ukraine - any statement should be proven, and any action should be naturally explained.

With a careful analysis of the materials of the above commissions, it becomes obvious that the narrow departmental preferences of the heads of these commissions clearly affected their preparation, which, in general, is natural. Therefore, the author is convinced that in Ukraine, only the National Academy of Sciences of Ukraine, which did not invent, design, build and operate the RBMK reactor, can really objectively and officially understand the true causes of the Chernobyl accident. And therefore, neither in relation to the reactor of the 4th unit, nor in relation to its personnel, she simply does not and cannot have any narrow departmental preferences. And her narrow departmental interest and direct official duty is the search objective truth, regardless of whether certain officials from the Ukrainian nuclear power industry like it or not.

The most important results of this analysis are outlined below.

1.3. About pressing the AZ-5 button or doubts grow into suspicions

It was noticed that when you get acquainted with the voluminous materials of the Government Commission for the Investigation of the Causes of the Chernobyl Accident (hereinafter - the Commission) quickly, you get the feeling that it managed to build a rather coherent and interconnected picture of the accident. But when you start to read them slowly and very carefully, then in some places there is a feeling of some kind of understatement. As if the Commission had not investigated something or had not said something. This is especially true for the episode of pressing the AZ-5 button.

“At 1 h 22 min 30 sec the operator on the printout of the program saw that the operational reactivity margin was a value requiring an immediate shutdown of the reactor. However, this did not stop the personnel, and the tests began.

At 1 h 23 min 04 sec. SRK (shut-off and control valves - auth.) TG (turbine generator - auth.) No. 8 ..... The existing emergency protection for closing the SRV .... was blocked to be able to repeat the test if the first attempt was unsuccessful ....

After a while, a slow increase in power began.

At 1:23 a.m. 40 seconds, the unit shift supervisor gave the command to press the AZ-5 emergency protection button, at the signal from which all emergency protection control rods are introduced into the core. The rods went down, but after a few seconds there were blows .... "/ 4 /.

The AZ-5 button is a button for emergency shutdown of the reactor. It is pressed in the most extreme case, when some emergency process begins to develop in the reactor, which cannot be stopped by other means. But it is clear from the quote that there were no special reasons to press the AZ-5 button, since not a single emergency process was noted.

The tests themselves were supposed to last 4 hours. As can be seen from the text, the staff intended to repeat their tests. And that would take another 4 hours. That is, the personnel were going to conduct the tests for 4 or 8 hours. But suddenly, already at the 36th second of testing, his plans changed, and he began to urgently shut down the reactor. Let's remind that 70 seconds ago, desperately risking, he did not do it contrary to the requirements of the Regulations. Almost all authors noted this obvious lack of motivation for pressing the AZ-5 / 5,6,9 / button.

Moreover, "From the joint analysis of DREG and teletype printouts, in particular, it follows that the emergency protection signal of the 5th category ... AZ-5 appeared twice, and the first one - at 01:23:39" / 7 / ... But there is information that the AZ-5 button was pressed three times / 8 /. The question is, why press it two or three times, if from the first time "the rods went down"? And if everything is in order, why are the staff so nervous? And physicists had suspicions that at 01 h 23 min 40 sec. or a little earlier something very dangerous did happen, which the Commission and the "experimenters" themselves kept silent about, and which forced the staff to abruptly change their plans to the exact opposite. Even at the cost of disrupting the electrical test program with all the ensuing administrative and material troubles for them.

These suspicions intensified when scientists, who studied the causes of the accident using primary documents (DREG printouts and oscillograms), discovered that they were not synchronized in time. Suspicions intensified even more when it was discovered that they had not been given the originals of the documents for study, but their copies, "on which there are no timestamps" / 6 /. It looked like an attempt to mislead scientists about the true chronology of the emergency process. And the scientists were forced to officially note that "the most complete information on the chronology of events is available only ... before the start of the tests at 01 h 23 min 04 sec on 04/26/86." / 6 /. And then "the factual information has significant gaps ... and there are significant contradictions in the chronology of the recovered events" / 6 /. Translated from the scientific and diplomatic language, this meant an expression of distrust of the submitted copies.

1.3. About movement of control rods

And most of all these contradictions can, perhaps, be found in the information about the movement of the control rods into the reactor core after pressing the AZ-5 button. Recall that after pressing the AZ-5 button, all control rods were to be immersed in the reactor core. Of these, 203 rods are from the upper limit switches. Consequently, by the time of the explosion, they should have plunged to the same depth, which should have been reflected by the arrows of the selsin at the control room-4. But in fact, the picture is completely different. For example, we will cite several works.

"The rods went down ..." and nothing else / 1 /.

"01 h 23 min: strong blows, the control rods stopped before reaching the lower limit switches. The clutch power key is removed." So it is written in the operational journal SIUR / 9 /.

"... about 20 rods remained in the upper extreme position, and 14-15 rods plunged into the core by no more than 1 .... 2 m ..." / 16 /.

"... the displacers of the emergency control rods traveled a distance of 1.2 m and completely displaced the water columns located under them ...." / 9 /.

The neutron-absorbing rods went down and almost immediately stopped, going deeper into the core by 2-2.5 m instead of 7 m "/ 6 /.

"The study of the end positions of the control rods using the selsyn sensors showed that about half of the rods stopped at a depth of 3.5 to 5.5 m" / 12 /. The question is, where did the other half stop, after all, after pressing the AZ-5 button, all (!) Rods should go down?

The position of the arrows of the position indicators of the rods preserved after the accident suggests that ... some of them have reached the lower limit switches (17 rods in total, of which 12 are from the upper limit switches) "/ 7 /.

From the above quotes, it can be seen that different official documents describe the process of the movement of the rods in different ways. And from the oral reports of the staff, it follows that the rods reached a mark of about 3.5 m, and then stopped. Thus, the main evidence of the movement of the rods into the core is the oral stories of the personnel and the position of the shooters of the selsins in the control room-4. No other evidence could be found.

If the position of the arrows were documented at the time of the accident, then on this basis it would be possible to confidently restore the process of its course. But, as it was found out later, this situation was "fixed according to the testimony of the selsins during the day on 26.04.86" / 5 /. 12-15 hours after the accident. And this is very important, because physicists who have worked with selsyn are well aware of their two "insidious" properties. First, if the selsyns sensors are exposed to an uncontrolled mechanical stress, then the arrows of the receivers can take any position. Second, if the power supply is removed from the selsins, then the arrows of the receivers can also take any position over time. This is not a mechanical clock, which, having broken, records, for example, the moment of an airplane crash.

Therefore, determining the depth of insertion of rods into the core at the time of the accident by the position of the arrows of the receivers at the control room-4 12-15 hours after the accident is a very unreliable method, because at the 4th block, both factors affected the selsyns. And this is indicated by the data of work / 7 /, according to which 12 rods, after pressing the AZ-5 button and before the explosion, traveled a path of 7 m from the upper limit switches to the lower ones. It is natural to ask how they managed to do this in 9 seconds, if the standard time for such a movement is 18-21 seconds / 1 /? There are obviously erroneous indications here. And how could 20 rods remain in the uppermost position if, after pressing the AZ-5 button, all (!) Control rods are introduced into the reactor core? This is also clearly erroneous testimony.

Thus, the position of the receivers-receivers arrows at the control room-4, recorded after the accident, cannot at all be considered objective scientific evidence that the control rods were inserted into the reactor core after pressing the AZ-5 button. What then remains of the evidence? Only subjective testimony of highly interested persons. Therefore, it would be more correct to leave the question of inserting rods open for the time being.

1.5. Seismic shock

In 1995, a new hypothesis appeared in the media, according to which. The Chernobyl accident was caused by a narrowly targeted earthquake of magnitude 3-4, which occurred in the area of ​​the Chernobyl nuclear power plant 16-22 seconds before the accident, which was confirmed by the corresponding peak on the seismogram / 10 /. However, atomic scientists immediately rejected this hypothesis as unscientific. In addition, they knew from seismologists that an earthquake of magnitude 3-4 with an epicenter in the north of the Kiev region is nonsense.

But in 1997, a serious scientific work / 21 / was published, in which, based on the analysis of seismograms obtained at once at three seismic stations located at a distance of 100-180 km from the Chernobyl nuclear power plant, the most accurate data on this incident were obtained. It followed from them that at 1 hour 23 minutes. 39 sec (± 1 sec) local time, 10 km east of the Chernobyl nuclear power plant, a "weak seismic event" occurred. The magnitude of the MPVA source, determined from surface waves, was in good agreement at all three stations and amounted to 2.5. The TNT equivalent of its intensity was 10 tons. It was impossible to estimate the depth of the source from the available data. In addition, due to the low level of amplitudes on the seismogram and the one-sided location of seismic stations relative to the epicenter of this event, the error in determining its geographic coordinates could not be higher than ± 10 km. Therefore, this "weak seismic event" could well have occurred at the location of the Chernobyl NPP / 21 /.

These results forced scientists to take a closer look at the geotectonic hypothesis, since the seismic stations where they were obtained turned out to be not ordinary, but supersensitive, for they followed underground nuclear explosions all over the world. And the fact that the earth was shaken 10 - 16 seconds before the official moment of the accident became an indisputable argument that could no longer be ignored.

But it immediately seemed strange that these seismograms were missing peaks from the explosion of the 4th block at its official moment. Objectively, it turned out that seismic vibrations, which no one in the world noticed, were recorded by the station instruments. But the explosion of the 4th block, which shook the earth so that it was felt by many, the same devices, capable of detecting an explosion of only 100 tons of TNT at a distance of 12,000 km, for some reason were not registered. But they should have registered an explosion with an equivalent power of 10 tons of TNT at a distance of 100-180 km. And this, too, did not fit into the logic.

1.6. A new version

All these contradictions and many others, as well as the lack of clarity in the materials on the accident on a number of issues, only increased the suspicions of scientists that the operators were hiding something from them. And over time, a seditious thought began to creep into my head, but did the opposite actually happen? First, there was a double explosion of the reactor. A 500 m high light violet flame shot up over the block. The entire building of the 4th block shook. The concrete beams were shaking. A steam-saturated blast wave burst into the control room (MCR-4). The general light went out. Only three lamps, powered by rechargeable batteries, remained lit. The personnel at the control room-4 could not fail to notice this. And only after that, recovering from the first shock, he rushed to press his "stop-cock" - the AZ-5 button. But it was already too late. The reactor went into oblivion. All this could take 10-20-30 seconds after the explosion. Then it turns out that the emergency process did not start at 1 hour 23 minutes. 40 seconds from pressing the AZ-5 button, and a little earlier. This means that an uncontrolled chain reaction in the reactor of Unit 4 began before the AZ-5 button was pressed.

In this case, clearly contradicting the logic of the seismic activity peaks recorded by supersensitive seismic stations in the Chernobyl nuclear power plant area at 01:23:39 am receive a natural explanation. It was a seismic response to the explosion of the 4th unit of the Chernobyl nuclear power plant.

And also receive a natural explanation and emergency repeated pressing of the AZ-5 button and the nervousness of the personnel in conditions when he was going to calmly work with the reactor for at least another 4 hours. And the presence of a peak on the seismogram at 1 hour 23 minutes. 39 seconds and his absence at the official moment of the accident. In addition, such a hypothesis would naturally explain the hitherto unexplained events that happened just before the explosion, such as, for example, "vibrations", "growing rumble", "water hammer" from the MCP / 10 /, "bouncing" of two thousand 80-kilogram pigs "assembly 11" in the Central hall of the reactor and much more / 11 /.

1.7. Quantitative evidence

The ability of the new version to naturally explain a number of previously unexplained phenomena, of course, are direct arguments in its favor. But these arguments are rather qualitative in nature. And irreconcilable opponents can only be convinced by quantitative arguments. Therefore, we will use the "proof by contradiction" method. Suppose that the reactor exploded "in a few seconds" after pressing the AZ-5 button and introducing graphite tips into the reactor core. Such a scheme obviously assumes that the reactor was in a controlled state before these actions, i.e. its reactivity was clearly close to 0ß. It is known that the introduction of all graphite tips at once can introduce additional positive reactivity from 0.2ß to 2ß, depending on the state of the reactor / 5 /. Then, with such a sequence of events, the total reactivity at some point could exceed the value of 1β, when an uncontrolled chain reaction on prompt neutrons begins in the reactor, i.e. explosive type.

If all this happened, then the designers and scientists should share responsibility for the accident together with the operators. If the reactor exploded before pressing the AZ-5 button or at the moment it was pressed, when the rods had not yet reached the core, then this means that its reactivity had already exceeded 1ß before these moments. Then, obviously, all the blame for the accident falls only on the personnel, who, simply put, lost control of the chain reaction after 01 hours 22 minutes 30 seconds, when the Regulations required them to shut down the reactor. Therefore, the question of what magnitude was the reactivity at the moment of the explosion became of fundamental importance.

The readings of the standard ZRTA-01 reactimeter would definitely help answer it. But they could not be found in the documents. Therefore, this issue was solved by different authors by mathematical modeling, during which the possible values ​​of total reactivity were obtained, ranging from 4ß to 10ß / 12 /. The balance of total reactivity in these works consisted mainly of the effect of a positive reactivity run-out during the movement of all control rods into the reactor core from the upper limit switches - up to + 2ß, from the vapor effect of reactivity - up to + 4ß and from the dehydration effect - up to + 4ß. Effects from other processes (cavitation, etc.) were considered second-order effects.

In all these works, the scheme of the accident development began with the formation of an emergency protection signal of the 5th category (AZ-5). This was followed by the introduction of all control rods into the reactor core, which contributed to the reactivity up to + 2ß. This led to the acceleration of the reactor in the lower part of the core, which led to the rupture of the fuel channels. Then the steam and void effects worked, which, in turn, could bring the total reactivity to + 10ß at the last moment of the reactor's existence. Our own estimates of the total reactivity at the moment of the explosion, carried out by the method of analogies on the basis of American experimental data / 13 /, gave a close value - 6-7ß.

Now, if we take the most plausible value of the reactivity 6ß and subtract from it the maximum possible 2ß introduced by the graphite tips, it turns out that the reactivity before the very insertion of the rods was already 4ß. And this reactivity in itself is quite sufficient for almost instantaneous destruction of the reactor. The lifetime of the reactor at such reactivity values ​​is 1-2 hundredths of a second. No staff, even the most selective, is able to react so quickly to a threat that has arisen.

Thus, quantitative assessments of reactivity before the accident show that an uncontrolled chain reaction began in the reactor of Unit 4 before the AZ-5 button was pressed. Therefore, pressing it could not be the cause of the thermal explosion of the reactor. Moreover, under the circumstances described above, it did not matter at all when this button was pressed - a few seconds before the explosion, at the moment of the explosion, or after the explosion.

1.8. What do the witnesses say?

During the investigation and the trial, the witnesses who were at the control panel at the time of the accident were actually divided into two groups. Those who were legally responsible for the safety of the reactor said that the reactor exploded after pressing the AZ-5 button. Those who were not legally responsible for the safety of the reactor said that the reactor exploded either before or immediately after pressing the AZ-5 button. Naturally, in their memoirs and testimonies, both of them tried to justify themselves in every possible way. Therefore, this kind of materials should be treated with some caution, which the author does, considering them only as auxiliary materials. Nevertheless, through this stream of verbal excuses, the validity of our conclusions is fairly well manifested. We will quote below some of the indications.

"The chief engineer for the operation of the second stage of the NPP ... who conducted the experiment, reported to me that, as is usually done, to shut down the reactor in the event of any emergency, he pressed the emergency protection button AZ-5" / 14 /.

This quote is from the memoirs of B.V. Rogozhkin, who worked as a shift supervisor at the station on the night of the emergency, clearly shows that at the 4th block, an "emergency" first arose, and only then the personnel began to press the AZ-5 button. A "emergency" in a thermal explosion of a reactor arises and passes very quickly - within seconds. If it has already arisen, then the staff simply does not have time to react.

"All events took place within 10-15 seconds. Some kind of vibration appeared. The rumble was growing rapidly. The reactor power at first dropped, and then began to increase, not giving in to regulation. Then - several sharp pops and two" water hammer ". The second is more powerful - with the sides of the central hall of the reactor. The lighting on the block board went out, the slabs of the suspended ceiling fell down, all the equipment was turned off "/ 15 /.

So he also describes the course of the accident itself. Naturally, without reference to the timeline. And here is another description of the accident, given by N. Popov.

"... there was a rumble of a completely unfamiliar character, very low tone, similar to a human groan (eyewitnesses of earthquakes or volcanic eruptions usually told about such effects). immediately there was a dull blow, accompanied by thunderous rumbles ... "/ 17 /.

"I. Kirshenbaum, S. Gazin, G. Lysyuk, who were present at the control panel, showed that they heard the command to shut down the reactor immediately before the explosion or immediately after it" / 16 /.

“At that time I heard Akimov’s command to jam the apparatus. Literally immediately there was a strong roar from the direction of the turbine hall” (From the testimony of A. Kukhar) / 16 /.

From these readings it already follows that the explosion and the pressing of the AZ-5 button practically coincided in time.

This important circumstance is also indicated by objective data. Recall that the first time the AZ-5 button was pressed at 01:23:39, and the second time, two seconds later (teletype data). Analysis of seismograms showed that the explosion at the Chernobyl NPP occurred in the period from 01 h 23 min 38 sec - 01 h 23 min 40 sec / 21 /. If we now take into account that the shift of the teletype time scale in relation to the time scale of the all-Union reference time could be ± 2 sec / 21 /, then we can confidently come to the same conclusion - the explosion of the reactor and pressing the AZ-5 button practically coincided in time. And this directly means that the uncontrolled chain reaction in the reactor of Unit 4 actually began before the first pressing of the AZ-5 button.

But what kind of explosion are we talking about in the testimony of witnesses, the first or the second? The answer to this question is contained in both seismograms and readings.

If the seismic station registered only one out of two weak explosions, it is natural to assume that they registered a stronger one. And this, according to the testimony of all witnesses, was precisely the second explosion. Thus, we can confidently assume that it was the second explosion that occurred in the period from 01 h 23 min 38 sec - 01 h 23 min 40 sec.

This conclusion is confirmed by witnesses in the following episode:

"The reactor operator L. Toptunov shouted about the emergency increase in the reactor power. Akimov shouted loudly:" Shut down the reactor! " " /16/.

It follows that by the time the AZ-5 button was pressed for the second time, the first explosion had already occurred. And this is very important for further analysis. This is where it will be useful to make a simple timing calculation. It is reliably known that the first pressing of the AZ-5 button was made at 01 h 23 min 39 sec, and the second - at 01 h 23 min 41 sec / 12 /. The time difference between clicks was 2 seconds. And to see the emergency readings of the device, to realize them and shout "about the emergency increase in power", you need to spend at least 4-5 seconds. To listen, then make a decision, give the command "Shut down the reactor!" So, we already have a margin of 8-10 seconds before the second pressing of the AZ-5 button. Recall that by this time the first explosion had already occurred. That is, it took place even earlier and obviously before the first pressing of the AZ-5 button.

How much earlier? Taking into account the inertia of a person's reaction to an unexpectedly arisen danger, usually measured in several seconds or more, let's throw another 8-10 seconds on it. And we get the time interval between the first and second explosions, equal to 16-20 s.

This our estimate of 16 - 20 s is confirmed by the testimony of the ChNPP employees O. A. Romantsev and A. M. Rudyk, who fished on the bank of the cooling pond on the emergency night. In their testimony, they practically repeat each other. Therefore, we will cite here the testimony of only one of them - Romantsev OA Perhaps, it was he who described the picture of the explosion in the greatest detail, as it was seen from a great distance. This is precisely their great value.

“I saw very well the flame above block # 4, which was shaped like a candle flame or a torch. It was very dark, deep purple, with all the colors of the rainbow. back and there was a second pop, similar to a bursting bubble of a geyser. 15 - 20 seconds later another torch appeared, which was narrower than the first, but 5-6 times higher. The flame also slowly grew, and then disappeared, like the first time The sound was like a cannon shot. Boomy and sharp. We drove "/ 25 /. It is interesting to note that both witnesses did not hear the sound after the first appearance of the flame. This means that the first explosion was very weak. A natural explanation for this will be given below.

True, in the testimony of A.M. Rudyk, a slightly different time elapsed between two explosions is indicated, namely 30 s. But this spread is easy to understand if we consider that both witnesses observed the picture of the explosion without a stopwatch in their hands. Therefore, their personal temporal sensations can be objectively characterized as follows - the time interval between two explosions was quite noticeable and amounted to a time measured in tens of seconds. By the way, an employee of the I.A.E. IV Kurchatova Vasilevsky VP, referring to witnesses, also comes to the conclusion that the time elapsed between two explosions is 20 s / 25 /. A more accurate estimate of the number of seconds elapsed between two explosions was carried out in this work above - 16 -20 s.

Therefore, it is in no way possible to agree with the estimates of the magnitude of this time interval of 1 - 3 sec, as is done in / 22 /. For these assessments were made on the basis of only the testimony of witnesses who were in various rooms of the Chernobyl nuclear power plant at the time of the accident, they did not see the general picture of the explosions and were guided in their testimony only by their sound sensations.

It is well known that an uncontrolled chain reaction ends in an explosion. This means that it began another 10-15 seconds earlier. Then it turns out that the moment of its beginning lies in the time interval from 01 h 23 min 10 s to 01 h 23 min 05 s. As it is not surprising, but it was this moment in time that the main witness of the accident for some reason considered it necessary to highlight when he discussed the question of the correctness or incorrectness of pressing the AZ-5 button exactly at 01:23:40 am (according to DREG): “I didn’t give it doesn't matter - the explosion would have occurred 36 seconds earlier "/ 16 /. Those. at 01 h 23 min 04 s. As already discussed above, at the same moment in time, back in 1986, the VNIIAES scientists pointed out as at the moment after which the chronology of the accident, reconstructed from the official copies of emergency documents presented to them, caused them doubts. Are there too many coincidences? It doesn't just happen. Apparently, the first signs of an accident ("vibrations" and "hum of a completely unfamiliar character") appeared approximately 36 seconds before the first pressing of the AZ-5 button.

This conclusion is confirmed by the testimony of the head of the pre-emergency, evening shift of the 4th unit, Yu. Tregub, who stayed on the night shift to help with the electrical experiment:

"The freewheel experiment begins.

The turbine is disconnected from steam and at this time they look at how long the run-out will last.

And so the command was given ...

We didn’t know how the equipment worked from running out, so in the first seconds I perceived ... some kind of bad sound appeared ... as if the Volga at full speed began to slow down and would go skidding. Such a sound: doo-doo-doo ... turning into a roar. There was a vibration of the building ...

The control room was trembling. But not like an earthquake. If you count to ten seconds, there was a rumble, the frequency of the oscillations dropped. And their power grew. Then there was a blow ...

This blow was not very good. Compared to what happened next. Although a strong blow. The control room shook. And when SIUT shouted, I noticed that the alarm of the main safety valves went off. Flashed in my mind: "Eight valves ... open state!". I bounced back, and at this time the second blow followed. That was a very strong blow. Plaster fell, the whole building came in ... the lights went out, then the emergency power supply was restored ... Everyone was in shock ... ".

The great value of these testimonies is due to the fact that the witness, on the one hand, worked as the head of the evening shift of the 4th unit and, therefore, knew well his real state and the difficulties of working on it, and, on the other hand, on the night shift he already worked simply a volunteer and, therefore, was legally not responsible for anything. Therefore, he was able to remember and in the most detail of all the witnesses to recreate the general picture of the accident.

In these testimonies, attention is drawn to the words: "in the first seconds ... there was some kind of bad sound." Hence, it clearly follows that the emergency situation at Unit 4, which ended in a thermal explosion of the reactor, arose already "in the first seconds" after the start of the electrical tests. And from the chronology of the accident it is known that they began at 01:23:00 04 sec. If we now add a few "first seconds" to this moment, then it turns out that an uncontrolled chain reaction on delayed neutrons in the reactor of Unit 4 began at about 01:23 a.m. 8-10 seconds, which pretty well coincides with our estimates of this moment, given above.

Thus, from a comparison of the emergency documents and the testimony of witnesses cited above, it can be concluded that the first explosion occurred approximately in the period from 01 h 23 min 20 sec to 01 h 23 min 30 sec. It was he who caused the first emergency pressing of the AZ-5 button. Let us recall that not a single official commission, not a single author of numerous versions could provide a natural explanation for this fact.

But why did the operating personnel of Unit 4, who were not new to the business and who also worked under the guidance of an experienced Deputy Chief Operations Engineer, still lose control of the chain reaction? Memories provide an answer to this question as well.

"We did not intend to violate the ORM and did not. Violation is when the testimony is deliberately ignored, and on April 26, no one saw a stock of less than 15 rods ... But, apparently, we looked through ..." / 16 /.

"Why Akimov delayed with the command to shut down the reactor, now you cannot find out. In the first days after the accident, we still talked until we were scattered in separate chambers ..." / 16 /.

These confessions were written by a direct, one might say, the main participant in emergency events many years after the accident, when no trouble was threatening him either from law enforcement agencies or from the former bosses, and he could write frankly. From them, it becomes obvious to any unbiased person that only the personnel are to blame for the explosion of the reactor of Unit 4. Most likely, carried away by the risky process of maintaining the power of the reactor, which fell into the self-poisoning mode through his own fault, at the level of 200 MW, the operating personnel first "overlooked" the unacceptably dangerous withdrawal of control rods from the reactor core in the amount prohibited by the Regulations, and then "delayed" with by pressing the AZ-5 button. This is the direct technical cause of the Chernobyl accident. And everything else is misinformation from the evil one.

And this is the time to end all these far-fetched disputes about who is to blame for the Chernobyl accident, and to blame everything on science, as the operators are very fond of doing. Scientists were right back in 1986.

1.9. About the adequacy of DREG printouts

It can be argued that the author's version of the causes of the Chernobyl accident contradicts its official chronology based on DREG printouts and cited, for example, in / 12 /. And the author agrees with this - indeed contradicts. But if you carefully analyze these printouts, it is easy to see that this chronology itself after 01:23:41 am is not confirmed by other emergency documents, contradicts the testimony of eyewitnesses and, most importantly, contradicts the physics of reactors. And the first to draw attention to these contradictions were the specialists of VNIIAES back in 1986, which was already mentioned above / 5, 6 /.

For example, the official chronology based on DREG printouts describes the accident process in the following sequence / 12 /:

01 h 23 min 39 sec (by teletype) - AZ-5 signal is registered. The rods AZ and RR began to move into the core.

01 hours 23 minutes 40 seconds (by DREG) - the same.

01 h 23 min 41 sec (via TTY) - An emergency protection signal has been registered.

01 h 23 min 43 sec (by DREG) - For all side ionization chambers (BIK), there were signals for the acceleration period (gas station) and for exceeding the power (АЗМ).

01 h 23 min 45 sec (by DREG) - Decrease from 28000 m3 / h to 18000 m3 / h of the MCP flow rates not participating in the coasting, and inaccurate readings of the MCP flow rates participating in the coasting ...

01 h 23 min 48 sec (by DREG) - Recovery of MCP flow rates, not participating in coasting, up to 29000 m3 / h. Further increase in pressure in the BS (left half - 75.2 kg / cm2, right - 88.2 kg / cm2) and the BS level. Actuation of high-speed reducing devices for dumping steam into the turbine condenser ..

01 h 23 min 49 sec - Emergency protection signal "pressure increase in the reactor space".

While the testimony of, for example, Lysyuk T.The. speak of a different sequence of emergency events:

"... I was distracted by something. Probably it was Toptunov's cry:" The reactor power is growing at an emergency speed! " and pressed the button "AZ-5" ... "/ 22 /.

A similar sequence of emergency events, already cited above, is described by the main witness of the accident / 16 /.

When comparing these documents, the following contradiction attracts attention. From the official chronology, it follows that the emergency increase in power began 3 seconds after the first press of the AZ-5 button. And the testimonies give the opposite picture, that at first the emergency growth of the reactor power began and only then, after a few seconds, the AZ-5 button was pressed. The estimate of the number of these seconds, carried out above, showed that the time interval between these events could be from 10 to 20 seconds.

The printouts of DREG directly contradict the physics of reactors. It was already mentioned above that the lifetime of a reactor with a reactivity above 4ß is hundredths of a second. And according to the printouts, it turns out that from the moment of the emergency increase in power, as many as 6 (!) Seconds passed before the technological channels began to burst.

Nevertheless, the overwhelming majority of authors for some reason completely neglect these circumstances and take the DREG printouts as a document that adequately reflects the accident process. However, as shown above, this is actually not the case. Moreover, this circumstance has long been well known to the personnel of the ChNPP, because the DREG program at the 4th unit of the ChNPP "was: implemented as a background task interrupted by all other functions" / 22 /. Consequently, "... the time of an event in DREG is not the real time of its manifestation, but only the time when the signal about the event was entered into the buffer (for subsequent recording on a magnetic tape)" / 22 /. In other words, these events could have taken place, but at a different, earlier time.

This most important circumstance was hidden from scientists for 15 years. As a result, dozens of specialists wasted a lot of time and money to find out physical processes which could lead to such a large-scale accident, relying on contradictory, inadequate printouts of DREG and the testimony of witnesses who were legally responsible for the safety of the reactor and therefore strongly personally interested in spreading the version - "the reactor exploded after pressing the AZ-5 button." At the same time, for some reason, no attention was systematically paid to the testimony of another group of witnesses who were not legally responsible for the safety of the reactor and, therefore, were more inclined to objectivity. And this most important, recently discovered circumstance additionally confirms the conclusions drawn in this work.

1.10. Conclusions of "competent authorities"

Immediately after the Chernobyl accident, five commissions and groups were organized to investigate its circumstances and causes. The first group of specialists was part of the Government Commission headed by B. Shcherbina. The second is the Commission of Scientists and Specialists under the Government Commission, headed by A. Meshkov and G. Shasharin. The third is the investigative group of the prosecutor's office. The fourth is a group of specialists from the Ministry of Energy, headed by G. Shasharin. The fifth is the commission of the ChNPP operators, which was soon liquidated by the order of the chairman of the Governmental Commission.

Each of them collected information independently of the other. Therefore, in their archives, there was a certain fragmentation and incompleteness in the emergency documents. Apparently, this led to the somewhat declarative nature of a number of important points in the description of the accident process in the documents prepared by them. This is clearly seen upon careful reading, for example, of the official report of the Soviet government to the IAEA in August 1986. Later in 1991, 1995 and 2000. additional commissions were formed by various authorities to investigate the causes of the Chernobyl accident (see above). However, this drawback remained unchanged in the materials prepared by them.

Little is known that immediately after the Chernobyl accident, the sixth investigation team, formed by the "competent authorities", worked to find out its causes. Without attracting much public attention to her work, she conducted her independent investigation of the circumstances and causes of the Chernobyl accident, relying on her unique informational capabilities. Following fresh traces, 48 ​​people were interviewed and interrogated within the first five days, and photocopies of many emergency documents were made. In those days, as you know, even the bandits respected the "competent authorities", well, and the normal employees of the Chernobyl nuclear power plant would not lie to them. Therefore, the findings of the "organs" were of extreme interest to scientists.

However, a very narrow circle of people was familiarized with these conclusions, which were classified as "top secret". Only recently did the SBU decide to declassify part of its Chernobyl materials stored in the archives. And although these materials are no longer officially classified, they still remain practically inaccessible to a wide range of researchers. Nevertheless, thanks to his persistence, the author managed to get to know them in detail.

It turned out that preliminary conclusions were made by May 4, 1986, and the final ones by May 11 of the same year. For brevity, here are just two quotes from these unique documents that are directly related to the topic of this article.

"... the common cause of the accident was the low culture of the NPP workers. This is not about qualifications, but about the culture of work, internal discipline and a sense of responsibility" (document No. 29 of May 7, 1986) / 24 /.

"The explosion occurred as a result of a number of gross violations of the rules of operation, technology and non-observance of the safety regime during the operation of the reactor of the 4th unit of the NPP" (document No. 31 of May 11, 1986) / 24 /.

This was the final conclusion of the "competent authorities". They never returned to this question.

As you can see, their conclusion almost completely coincides with the conclusions of this article. But there is a "slight" difference. The National Academy of Sciences of Ukraine came to them only 15 years after the accident, figuratively speaking, through a thick fog of misinformation on the part of interested parties. And the "competent authorities" finally established the true causes of the Chernobyl accident in just two weeks.

2. Accident scenario

2.1. Initial event

The new version made it possible to substantiate the most natural scenario of the accident. At the moment, he appears to be like that. At 00 hours 28 minutes on 26.04.86, switching to the electrical test mode, the personnel at the control room-4 made a mistake when switching control from the local automatic control system (LAR) to the automatic power control system of the main range (AR). Because of this, the thermal power of the reactor fell below 30 MW, and the neutron power dropped to zero and remained so for 5 minutes, judging by the readings of the neutron power recorder / 5 /. The reactor automatically began the process of self-poisoning by short-lived fission products. By itself, this process posed no nuclear threat. On the contrary, as it develops, the reactor's ability to maintain a chain reaction decreases until it stops completely, regardless of the will of the operators. All over the world, in such cases, the reactor is simply shut down, then they wait a day or two until the reactor recovers its working capacity. And then they start it up again. This procedure is considered an ordinary one, and did not present any difficulties for the experienced personnel of the 4th unit.

But at NPP reactors, this procedure is very troublesome and takes a lot of time. And in our case, she still disrupted the implementation of the electrical test program with all the ensuing troubles. And then, in an effort to "finish the tests as quickly as possible," as the personnel later explained, they began to gradually remove the control rods from the reactor core. This conclusion was supposed to compensate for the decrease in reactor power due to self-poisoning processes. This procedure is also common at NPP reactors and poses a nuclear threat only if there are too many of them for the given state of the reactor. When the number of the remaining rods reached 15, the operating personnel had to shut down the reactor. This was his direct duty. But he didn't.

By the way, the first time such a violation occurred at 0710 hours on April 25, 1986, i.e. almost a day before the accident, and lasted until about 14 hours (see Fig. 1). It is interesting to note that during this time the shifts of the operating personnel changed, the shift supervisors of the 4th unit changed, the station shift supervisors and other station bosses changed, and, oddly enough, none of them raised an alarm, as if everything was in order. although the reactor was already on the verge of an explosion .. The conclusion involuntarily suggests itself that violations of this type, apparently, were a common occurrence not only at the 5th shift of the 4th unit.

This conclusion is confirmed by the testimony of I.I. Kazachkov, who worked on April 25, 1986 as the head of the day shift of the 4th unit: "I will say this: we have repeatedly had less than the permissible number of rods - and nothing ...", "... none of us imagined that this was fraught a nuclear accident. We knew that this should not be done, but we did not think ... "/ 18 /. Figuratively speaking, the reactor “resisted” such a free treatment for a long time, but the personnel still managed to “rape” him and bring him to an explosion.

The second time it happened was on April 26, 1986, shortly after midnight. But for some reason, the staff did not shut down the reactor, but continued to withdraw the rods. As a result, at 01 hours 22 minutes 30 seconds. 6-8 control rods remained in the core. But this did not stop the staff, and they started electrical tests. At the same time, it can be confidently assumed that the personnel continued to withdraw the rods until the very moment of the explosion. This is indicated by the phrase "a slow increase in power began" / 1 / and the experimental curve of the change in the reactor power as a function of time / 12 / (see Fig. 2).

In the whole world, no one works like that, because there are no technical means of safe control of a reactor in the process of self-poisoning. The staff of the 4th unit did not have them either. Of course, none of them wanted to blow up the reactor. Therefore, the withdrawal of rods in excess of the permitted 15 could be carried out only on the basis of intuition. From a professional point of view, this was already an adventure in its purest form. Why did they go for it? This is a separate issue.

At some point between 01 h 22 min 30 sec and 01 h 23 min 40 sec, the intuition of the personnel apparently changed, and an excess number of rods were removed from the reactor core. The reactor went into the mode of maintaining a chain reaction on prompt neutrons. The technical means for controlling reactors in this mode have not yet been created, and it is unlikely that they will ever be created. Therefore, within hundredths of a second, the heat release in the reactor increased 1500-2000 times / 5.6 /, the nuclear fuel was heated to a temperature of 2500-3000 degrees / 23 /, and then the process began, which is called the thermal explosion of the reactor. Its consequences made the Chernobyl nuclear power plant "famous" all over the world.

Therefore, it would be more correct to consider the excessive withdrawal of rods from the reactor core as an event that initiated an uncontrolled chain reaction. As it happened in other nuclear accidents that ended with a thermal explosion of the reactor in 1961 and 1985. And after the rupture of the channels, the total reactivity could have increased due to the vapor and void effects. To assess the individual contribution of each of these processes, detailed modeling of the most complex and least developed, second phase of the accident is required.

The scheme of the Chernobyl accident development proposed by the author seems to be more convincing and more natural than the introduction of all the rods into the reactor core after a belated pressing of the AZ-5 button. For the quantitative effect of the latter, according to different authors, has a rather large scatter from sufficiently large 2ß to negligible 0.2ß. It is not known which of them was realized during the accident and whether it was realized at all. In addition, "as a result of research by various teams of specialists ... it became clear that one injection of positive reactivity only by the control rods, taking into account all feedbacks affecting the steam content, is not enough to reproduce such a power surge, the beginning of which was registered by the SCALA IV centralized control system. power unit of the ChNPP "/ 7 / (see Fig. 1).

At the same time, it has long been known that the withdrawal of control rods from the reactor core itself can give a much larger reactivity run-out - more than 4ß / 13 /. This is, first of all. And, secondly, it has not yet been scientifically proven that the rods generally entered the core. From the new version, it follows that they could not enter there, because at the moment the AZ-5 button was pressed, neither the rods nor the core existed.

Thus, the version of the operators, having withstood the test of qualitative arguments, did not withstand the quantitative test and can be put into the archive. And the version of scientists, after a small amendment, received additional quantitative confirmation.

Rice. 1. Power (Np) and operational reactivity margin (Rop) of the reactor of the 4th unit in the time interval from 04/25/1986 to the official moment of the accident on 04/26/1986 / 12 /. Pre-emergency and emergency periods of time are marked with an oval.

2.2. "The first explosion"

An uncontrolled chain reaction in the reactor of Unit 4 began in some, not very large part of the core and caused local overheating of the cooling water. Most likely, it began in the southeastern quadrant of the core at an altitude of 1.5 to 2.5 m from the base of the reactor / 23 /. When the pressure of the steam-water mixture exceeded the strength limits of the zirconium pipes of the technological channels, they burst. The rather superheated water almost instantly turned into steam of rather high pressure. This steam, expanding, pushed the massive 2,500-ton reactor lid upward. For this, as it turned out, the rupture of just a few technological channels was quite enough. This ended the initial stage of the destruction of the reactor and began the main one.

Moving up, the cover sequentially, like in a domino, tore the rest of the technological channels. Many tons of superheated water almost instantly turned into steam, and the force of its pressure already quite easily threw the "lid" to a height of 10-14 meters. A mixture of steam, fragments of graphite masonry, nuclear fuel, technological channels and other structural elements of the reactor core rushed into the resulting vent. The cover of the reactor unfolded in the air and fell back on its edge, crushing the upper part of the core and causing additional release of radioactive substances into the atmosphere. The blow from this fall can explain the double nature of the "first explosion".

Thus, from the point of view of physics, the "first explosion" was not actually an explosion as a physical phenomenon, but was a process of destruction of the reactor core by superheated steam. Therefore, the employees of the Chernobyl NPP, who were fishing on the emergency night on the shore of the cooling pond, did not hear the sound after it. That is why seismic instruments at three supersensitive seismic stations from a distance of 100 - 180 km were able to register only the second explosion.

Rice. 2. Change in the power (Np) of the reactor of the 4th unit in the time interval from 11:00 pm on 04/25/1986 to the official moment of the accident on 04/26/1986 (enlarged section of the graph, enclosed by an oval in Fig. 1). Attention is drawn to the constant growth of the reactor power right up to the explosion itself

2.3. "Second explosion"

In parallel with these mechanical processes, various chemical reactions began in the reactor core. Of these, the exothermic steam-zirconium reaction is of particular interest. It starts at 900 ° С and goes violently already at 1100 ° С. Its possible role was studied in more detail in the work / 19 /, in which it was shown that under the conditions of an accident in the reactor core of the 4th unit, only due to this reaction, up to 5000 cubic meters could be formed within 3 seconds. meters of hydrogen.

When the top "cover" flew into the air, this mass of hydrogen burst out of the reactor shaft into the central hall. Mixing with the air in the central hall, hydrogen formed a detonation air-hydrogen mixture, which then exploded, most likely from an accidental spark or red-hot graphite. The explosion itself, judging by the nature of the destruction of the central hall, had a blasting and volumetric character, similar to the explosion of the well-known "vacuum bomb" / 19 /. It was he who shattered the roof, the central hall and other rooms of the 4th block.

After these explosions, the process of formation of lava-like fuel-containing materials began in the under-reactor rooms. But this unique phenomenon is already a consequence of the accident and is not considered here.

3. Key findings

1. The root cause of the Chernobyl accident was the unprofessional actions of the personnel of the 5th shift of the 4th unit of the Chernobyl NPP, who, most likely, carried away by the risky process of maintaining the power of the reactor, which got into the self-poisoning mode through the fault of the personnel, at the level of 200 MW, first "overlooked" dangerous and prohibited by the regulations, the withdrawal of control rods from the reactor core, and then "delayed" by pressing the emergency shutdown button of the AZ-5 reactor. As a result, an uncontrolled chain reaction began in the reactor, which ended in a thermal explosion.

2. The introduction of graphite displacers of control rods into the reactor core could not be the cause of the Chernobyl accident, since at the moment of the first pressing of the AZ-5 button at 01:23 a.m. 39 sec. neither the control rods nor the core existed anymore.

3. The reason for the first pressing of the AZ-5 button was the "first explosion" of the reactor of Unit 4, which occurred approximately in the period from 01 h 23 min. 20 sec. until 01 h 23 min. 30 sec. and destroyed the reactor core.

4. The second pressing of the AZ-5 button took place at 01:23. 41 sec. and practically coincided in time with the second, already real explosion of the air-hydrogen mixture, which completely destroyed the building of the reactor compartment of the 4th block.

5. The official chronology of the Chernobyl accident, based on the DREG printouts, does not adequately describe the accident process after 01:23. 41 sec. VNIIAES specialists were the first to draw attention to these contradictions. There is a need for its official revision, taking into account the recently discovered new circumstances.

In conclusion, the author considers it his pleasant duty to express deep gratitude to Corresponding Member of NASU A. A. Klyuchnikov, Doctor of Physical and Mathematical Sciences A. A. Borovoy, Doctor of Physical and Mathematical Sciences E. V. Burlakov, Doctor of Technical Sciences E. M. Pazukhin and VN Shcherbin, Candidate of Technical Sciences, for a critical but friendly discussion of the results and moral support.

The author also considers it his especially pleasant duty to express deep gratitude to General of the SBU Yu. V. Petrov for the opportunity to get acquainted in detail with part of the SBU archival materials related to the Chernobyl accident, and for oral comments on them. They finally convinced the author that the “competent authorities” are indeed competent authorities.

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