The Chernobyl accident

The Chernobyl accident
A type	radiation accident
Country	the USSR
A place	Chernobyl district , Kiev region , USSR , USSR
date	April 26, 1986
Time	1:23 (21:23 UTC )
Dead	up to 50 from causes directly related to the accident, up to 4000 (including projected deaths) from the long-term effects of exposure
Chernobyl NPP named after V.I. Lenin

The accident at the Chernobyl nuclear power plant (also known as the Chernobyl accident , the Chernobyl accident , the Chernobyl disaster, or simply Chernobyl ) - the destruction on April 26, 1986, of the fourth power unit of the Chernobyl nuclear power plant located near the city of Pripyat ( Ukrainian SSR , now Ukraine ). The destruction was explosive, the reactor was completely destroyed, and a large amount of radioactive was released into the environment.substances. The accident is regarded as the largest of its kind in the entire history of nuclear energy , both in terms of the estimated number of people killed and affected by its consequences, and in terms of economic damage.

During the first three months after the accident, 31 people died, another 19 deaths from 1987 to 2004 can be attributed to its direct consequences. 134 people from among the liquidators suffered acute radiation sickness of varying severity. High doses of radiation to people, mainly from emergency workers and liquidators, have served or can cause four thousand additional deaths from the long-term effects of radiation ^{[1] [2]} . Nevertheless, these figures are significantly less than the number of victims attributed to public opinion about the Chernobyl disaster ^[3] .

Unlike the bombings of Hiroshima and Nagasaki , the explosion resembled a very powerful “ dirty bomb ” - radioactive contamination became the main damaging factor . The cloud formed by the burning reactor spread various radioactive materials, primarily radionuclides of iodine and cesium , for the most part of Europe. The greatest fallout near the reactor was observed in the territories belonging to Belarus , the Russian Federation and Ukraine ^[4] . From the 30-kilometer exclusion zone around the nuclear power plant, the entire population was evacuated - more than 115 thousand people ^[2]. Significant resources were mobilized to eliminate the consequences, more than 600 thousand people participated in the aftermath of the accident ^[5] .

The Chernobyl accident became an event of great socio-political significance for the USSR. All this left a definite imprint on the course of the investigation of its causes ^[6] . Experts do not have a single opinion on the exact causes of the accident, the versions of different nuclear scientists are similar in general terms and differ in the specific mechanisms of the emergence and development of the emergency .

NPP characteristics

The Chernobyl NPP named after V.I. Lenin ( ) is located on the territory of Ukraine 3 km from the city of Pripyat , 18 km from the city Chernobyl , 16 km from the border with Belarus and 110 km from Kiev .

At the time of the accident at the Chernobyl nuclear power plant operated on the basis of four power reactors RBMK-1000 reactors (RBMK type) with an electrical capacity of 1000 MW (thermal power - 3200 MW) each. Two more similar power units were under construction. The fifth power unit was 80% complete. For the sixth power unit they managed to dig a pit. Chernobyl produced about a tenth of the electricity of the Ukrainian SSR .

Chernobyl stopped forever on December 15, 2000 .

The capacity of Chernobyl NPP was 12,800 MW (thermal) and 4,000 MW (electric).

Crash

At 01:23:47 on Saturday April 26, 1986, an explosion occurred at the 4th unit of the Chernobyl nuclear power plant, which completely destroyed the reactor. The building of the power unit partially collapsed, while the operator of the main circulation pumps Valery Hodemchuk died. A fire started in various rooms and on the roof . Commissioner Vladimir Shashenok died from his injuries at 6:00 the same day. Subsequently, the remains of the core melted, a mixture of molten metal, sand, concrete and fragments of fuel spread over the subreactor rooms ^{[7] [8]} . The accident resulted in the release of radioactive substances into the environment , including uranium isotopes , plutonium , iodine-131 ( half-life  - 8 days), cesium-134 (half-life - 2 years), cesium-137 (half-life - 30 years), strontium-90 (half-life - 28.8 years).

Chronology

On April 25, 1986, it was planned to stop the 4th power unit of the Chernobyl nuclear power plant for the next scheduled preventive repair. During such stops, various tests of equipment are usually carried out, both routine and non-standard, carried out according to separate programs. This time, the goal of one of them was to test the so-called “ turbine generator rotor run-out” mode , proposed by the general designer (Moscow Hydroproject Institute ) as an additional emergency power supply system. Run-out mode would allow the use of kinetic energystored in the rotating rotor of the turbogenerator, to provide power to the feed (PEN) and main circulation pumps (MCP) in case of power failure to supply the station's own needs. However, this regime was not worked out or introduced at nuclear power plants with RBMK . These were already the fourth regime tests conducted at the Chernobyl nuclear power plant. The first attempt in 1982 showed that coasting voltage drops faster than planned. Subsequent tests carried out after the completion of the equipment of the turbogenerator in 1983-1985 also failed for various reasons ^[9] .

The tests were to be carried out on April 25, 1986 at a power of 700–1000 MW (thermal), 22–31% of the total power ^[10] . About a day before the accident (by 3:47 on April 25), the reactor power was reduced to about 50% (1600 MW) ^[11] . At 14:00, in accordance with the program, the emergency reactor cooling system was turned off. However, a further decrease in capacity was prohibited by the Kyivenergo dispatcher. The ban was lifted by the dispatcher at 23:10. During long-term operation of the reactor at a power of 1600 MW, unsteady xenon poisoning occurred . During April 25, the peak of poisoning was passed, and the poisoning of the reactor began. By the time of obtaining permission to further reduce the power operational reactivity margin(OZR) increased almost to its initial value and continued to increase. With a further decrease in power, the poisoning stopped and the poisoning started again.

Within about two hours, the reactor power was reduced to the level stipulated by the program (about 700 MW thermal), and then, for an unknown reason, to 500 MW. At 0:28, when switching from a local automatic control system to an automatic controller of total power, the operator (SIUR) could not keep the reactor power at a given level, and it failed (thermal - up to 30 MW, neutron - to zero) ^{[9] [11]} . The personnel located at the control room-4 decided to restore the reactor power (by removing the absorbing rods of the reactor) ^{[9] [12]}and a few minutes later achieved its growth, and later stabilization at the level of 160-200 MW (thermal). At the same time, OEC was continuously decreasing due to ongoing poisoning. Accordingly, operators continued to remove the manual control rods (PP) ^[11] .

After reaching 200 MW of thermal power, additional main circulation pumps were switched on , and the number of working pumps was brought up to eight. According to the test program, four of them, together with two additionally working PEN pumps, were supposed to serve as a load for the generator of the “running out” turbine during the experiment. An additional increase in the flow rate of the coolant through the reactor led to a decrease in vaporization. In addition, the consumption of relatively cold feed water remained small, corresponding to a power of 200 MW, which caused an increase in the temperature of the coolant at the entrance to the core, and it approached the boiling point ^[11] .

At 1:23:04 the experiment began. Due to a decrease in the speed of the pumps connected to the “run-out” generator and a positive steam reactivity coefficient (see below), the reactor tended to increase power (positive reactivity was introduced ), however, for almost the entire time of the experiment, the behavior of the power did not inspire concern.

At 1:23:39, the emergency alarm AZ-5 ^[13] from pressing a button on the operator’s console was registered . The absorbing rods began to move into the active zone, however, due to their unsuccessful design and low (non-scheduled) operational reactivity margin, the reactor was not shut off, but rather began to accelerate. After 1-2 seconds, a message fragment was recorded, similar to the AZ-5 repeated signal. In the next few seconds, various signals were recorded, indicating a very rapid increase in power, then the recording systems failed.

According to various accounts, one to several powerful blows occurred (most witnesses pointed to two powerful explosions), and by 1: 23: 47–1: 23: 50 the reactor was completely destroyed ^{[9] [11] [12] [14 ] [15]} .

Causes of the accident and investigation

There are at least two different approaches to explaining the causes of the Chernobyl accident, which can be called official, as well as several alternative versions of varying degrees of reliability.

The State Commission, formed in the USSR to investigate the causes of the disaster, laid the main responsibility for it on the operational personnel and the leadership of the Chernobyl nuclear power plant. The IAEA has established its advisory group known as the Advisory Council for Nuclear Safety and Security Committee ( Eng. INSAG; International Nuclear Safety Advisory Group ), which, based on materials provided by the Soviet side and oral statements by specialists (the delegation of Soviet specialists was headed by Valery Legasov , IAE First Deputy Director named after I.V. Kurchatov) in his 1986 report ^{[ sixteen]} also generally supported this view. It was alleged that the accident was the result of the unlikely coincidence of a number of violations of the rules and regulations by operating personnel, and it had catastrophic consequences due to the fact that the reactor was brought into an unregulated state ^[17] .

Gross violations of NPP operating rules committed by its personnel, according to this point of view, are as follows ^[17] :

• conducting the experiment at any cost, despite the change in the state of the reactor;
• decommissioning of operational technological protections that would simply stop the reactor even before it fell into dangerous mode;
• silence on the scale of the accident in the early days of the Chernobyl leadership.

However, in 1991, the USSR Gosatomnadzor commission reconsidered this issue and came to the conclusion that “the Chernobyl accident that began as a result of the operations personnel acquired an inadequate catastrophic scale due to the unsatisfactory design of the reactor” ( ^[18] , p. 35). In addition, the commission analyzed the regulatory documents in force at the time of the accident and did not confirm some of the charges previously put forward against station personnel.

In 1993, INSAG published an additional report ^[11]who updated "the part of the INSAG-1 report that focuses on the causes of the accident" and focuses more on serious problems in the design of the reactor. It is mainly based on the data of the USSR Gosatomnadzor and on the report of the “working group of experts of the USSR” (these two reports are included as appendices), as well as on new data obtained as a result of the accident simulation. In this report, many of the conclusions made in 1986 were considered incorrect and “some details of the scenario presented in INSAG-1” are revised, as well as some “important conclusions” are changed. According to the report, the most likely cause of the accident was the design and reactor design errors, these design features had a major impact on the course of the accident and its consequences ^[19] .

The main factors that contributed to the accident, INSAG-7 considers the following ^[20] :

• the reactor did not comply with safety standards and had dangerous structural features;
• low quality of operating regulations in terms of ensuring safety;
• inefficiency of the regulatory regime and oversight of safety in nuclear energy, general lack of safety culture in nuclear issues both at the national and local levels;
• there was no effective exchange of safety information both between operators and between operators and designers, the staff did not have a sufficient understanding of the plant's features that affect safety;
• personnel made a number of errors and violated existing instructions and the test program.

In general, INSAG-7 cautiously formulated its conclusions about the causes of the accident. For example, when evaluating various scenarios, INSAG notes that “in most analytical studies, the severity of the accident is associated with design flaws of the control and protection system (CPS) rods in combination with the physical design characteristics,” and without expressing his opinion, he speaks about “Other traps for operating personnel. Any of them could equally cause an event initiating such or almost identical accident ”, for example, such an event as“ failure or cavitation of pumps ”or“ destruction of fuel channels ”. Then the rhetorical question is asked: "Does it really matter which shortcoming was the real reason, if any of them could potentially be the determining factor?"In setting out its views on the design of the reactor, INSAG recognizes as “the most probable final event causing the accident” the “entry of the CPS rods at the critical moment of testing” and notes that “in this case the accident would be the result of the application of dubious regulations and procedures that would lead to the manifestation and combination of the two serious design defects in the design of the rods and positive feedback on reactivity. " It goes on to say: “It is unlikely that it actually matters if a positive outflow of reactivity during an emergency shutdown was the last event that caused the destruction of the reactor. The only important thing is that such a flaw existed and it could be the cause of the accident ”that “in this case, the accident would result from the application of dubious regulations and procedures that would lead to the manifestation and combination of two serious design defects in the design of the rods and positive feedback on reactivity”. It goes on to say: “It is unlikely that it actually matters if a positive outflow of reactivity during an emergency shutdown was the last event that caused the destruction of the reactor. The only important thing is that such a flaw existed and it could be the cause of the accident ”that “in this case, the accident would result from the application of dubious regulations and procedures that would lead to the manifestation and combination of two serious design defects in the design of the rods and positive feedback on reactivity”. It goes on to say: “It is unlikely that it actually matters if a positive outflow of reactivity during an emergency shutdown was the last event that caused the destruction of the reactor. The only important thing is that such a flaw existed and it could be the cause of the accident ”whether the positive reactivity overrun during an emergency shutdown was the last event that caused the destruction of the reactor. The only important thing is that such a flaw existed and it could be the cause of the accident ”whether the positive reactivity overrun during emergency shutdown was the last event that caused the destruction of the reactor. The only important thing is that such a flaw existed and it could be the cause of the accident ”^[19] . INSAG generally prefers not to talk about the causes, but about the factors that contributed to the development of the accident. So, for example, in the conclusions the cause of the accident is formulated as follows: “It is not known with certainty where the power surge began, which led to the destruction of the Chernobyl nuclear power plant reactor. A certain positive reactivity, apparently, was introduced as a result of the increase in vapor content with a decrease in coolant flow rate. The introduction of additional positive reactivity as a result of immersion of fully withdrawn CPS rods during the tests was probably the decisive factor leading to the accident ” ^[20] .

The technical aspects of the accident are considered below, which are mainly caused by the shortcomings of RBMK reactors, as well as violations and errors made by the station personnel during the last test for the 4th Chernobyl NPP unit.

Reactor shortcomings

The RBMK-1000 reactor had a number of design flaws and, as of April 1986, had dozens of violations and deviations from existing nuclear safety rules ^[18] . Two of these shortcomings were directly related to the causes of the accident. This is a positive feedback between power and reactivity that arose under certain operating conditions of the reactor, and the presence of the so-called end effectmanifested under certain operating conditions. These shortcomings were not properly reflected in the design and operational documentation, which largely contributed to the erroneous actions of the operating personnel and the creation of conditions for the accident. After the accident, as a matter of urgency (primary - in May 1986), measures were taken to eliminate these shortcomings ^[18] .

Positive Steam Reactivity

During the operation of the reactor, water is pumped through the active zone, which is used as a coolant , but is also a moderator and a neutron absorber, which significantly affects reactivity. Inside the reactor, it boils , partially turning into steam , which is the worst moderator and absorber than water (per unit volume). The reactor was designed so that the steam reactivity coefficientwas positive, that is, an increase in the intensity of vaporization contributed to the release of positive reactivity (causing an increase in reactor power). Under the conditions in which the power unit operated during the experiment (low power, large burnup, lack of additional absorbers in the core), the effect of the positive vapor coefficient was not compensated by other phenomena affecting the reactivity, and the reactor had a positive fast power reactivity coefficient ^[21] . This means that there was a positive feedback. - the increase in power caused such processes in the core that led to even greater growth in power. This made the reactor unstable and nuclear hazardous. In addition, the operators were not informed that at low powers a positive feedback may occur ( ^[18] , pp. 45–47) ^[22] .

"End effect"

The “ end effect ” in the RBMK reactor arose due to the unsuccessful design of the CPS rods and was subsequently recognized as a design error ^[18] and, as a result, one of the causes of the accident. The essence of the effect is that under certain conditions, during the first few seconds of immersion of the rod in the active zone, positive reactivity was introduced instead of negative. Structurally, the rod consisted of two sections: an absorber ( boron carbide ) full length of the active zone and a displacer ( graphite), displacing water from the part of the CPS channel with the absorber completely removed. The manifestation of this effect became possible due to the fact that the CPS rod, located in its highest position, leaves a seven-meter column of water below, in the middle of which there is a five-meter graphite displacer. Thus, a five-meter graphite displacer remains in the reactor core, and a column of water remains in the CPS channel under the rod, which is in its highest position. Substitution when the rod moves down the lower column of water with graphite with a lower neutron capture cross section than that of water, and caused the release of positive reactivity.

When the rod is immersed in the reactor core, water is displaced in its lower part, but at the same time in the upper part graphite (displacer) is replaced by boron carbide (absorber), and this introduces negative reactivity. What outweighs and what sign the total reactivity will depend on the shape of the neutron field and its stability (when moving the rod). And this, in turn, is determined by many factors of the initial state of the reactor.

For the manifestation of the end effect in full (the introduction of a sufficiently large positive reactivity), a rather rare combination of initial conditions is necessary ^[23] .

Independent studies of the recorded data on the Chernobyl accident, carried out in various organizations, at different times and using different mathematical models, showed that such conditions existed at the time the AZ-5 button was pressed at 1:23:39. Thus, the operation of the emergency protection AZ-5 could be, due to the end effect, the initial event of the Chernobyl accident on April 26, 1986 ( ^[18] , p. 81). The existence of the end effect was discovered in 1983 during physical launches of the 1st power unit of the Ignalina NPP and the 4th power unit of the Chernobyl NPP ( ^[18], from. 54). About this, the chief designer sent letters to nuclear power plants and to all interested organizations. The special danger of the discovered effect was noticed in the organization of the supervisor, and a number of measures were proposed to eliminate and neutralize it, including conducting detailed studies. But these proposals were not implemented, and there is no evidence that any studies were carried out, as well as (except for the letter of the Civil Code) that the operating personnel of the NPP knew about the end effect.

Protective system performance

The emergency protection rods at RBMK-1000 were controlled by the same drives as the control rods for controlling the reactor in normal operation. At the same time, the response time of the AZ-5 protection system when the rods were dropped from the highest position was 18-21 seconds ^[24] . In the design of the RBMK-1000 reactor, such a speed of movement of the CPS bodies was not substantiated in any way, and according to INSAG-7 it was insufficient. In general, the logic of operation of the control and protection system (CPS) of the reactor was built on the basis of the desire to ensure the efficient operation of the station in the power system, therefore, when an alarm occurred, priority was given to quickly reducing power to "certain levels" rather than guaranteed shutdown of the reactor ^[11] .

Operator Errors

It was initially alleged ^[16] that in the process of preparing and conducting the experiment, operating personnel made a number of violations and errors and that it was these actions that became the main cause of the accident. However, then this point of view was revised and it became clear ^[11] that most of these actions were not violations or did not affect the development of the accident ^[25]. Thus, long-term operation of the reactor at a power below 700 MW was not prohibited by the regulations that were in force at that time, as previously stated, although it was a mistake in operation and a factor contributing to the accident. In addition, this was a deviation from the approved test program. In the same way, the inclusion of all eight main circulation pumps (MCPs) was not prohibited by the operational documentation. The violation of the regulation was only an excess of the flow through the MCP above the limit value, but cavitation(which was considered as one of the causes of the accident) it did not cause. Shutdown of the reactor emergency cooling system (SAOR) was allowed, subject to the necessary approvals. The system was blocked in accordance with the approved test program, and the necessary permission from the chief engineer of the station was obtained. This did not affect the development of the accident: by the time the SAOR could work, the core was already destroyed. Blocking the reactor protection by the stop signal of two turbogenerators was not only allowed, but, on the contrary, was prescribed when the power unit was unloaded before it was stopped ( ^[18] , p. 90).

Thus, the listed actions were not a violation of the operating regulations; moreover, reasonable doubts are expressed that they somehow influenced the occurrence of the accident under the conditions that prevailed before their implementation ( ^[18] , p. 78). It is also recognized that “operations with the values ​​of the settings and the shutdown of technological protections and interlocks did not cause the accident, did not affect its scale. These actions had nothing to do with emergency protection of the reactor itself (in terms of power level, in terms of its growth rate), which the personnel did not take out of operation ”( ^[18] , p. 92). Moreover, the violation of the regulation was only the non-switching of the protection setting for the water level in the drum separator (from −1100 to −600 mm), but not the change in the setting for steam pressure (from 55 to 50 kgf / cm²).

A violation of the regulations that significantly affected the occurrence and course of the accident was, undoubtedly, the operation of a reactor with a small operational reactivity margin (OZR). At the same time, it was not proved that an accident could not have happened without this violation ^[19] .

Regardless of which specific violations of the regulations the operating personnel committed and how they affected the occurrence and development of the accident, the personnel supported the operation of the reactor in a dangerous mode. Operation at a low power level with an increased coolant flow rate and at a small OZR was a mistake ( ^[26] , p. 121) regardless of how these modes were presented in the operating procedure and regardless of the presence or absence of errors in the reactor design ^[20] .

The role of operational reactivity margin

In the analysis of the development of the Chernobyl accident, much attention is paid to the operational reactivity reserve (OZR). OZR is the positive reactivity that a reactor would have with the CPS rods fully removed. In a reactor operating at a constant power level, this reactivity is always compensated (to zero) by the negative reactivity introduced by the CPS rods. A large OZR value means an “increased" proportion of the excess nuclear fuel (uranium-235) spent to compensate for this negative reactivity, instead of this uranium-235 also being used for fission and energy production. In addition, the increased value of the ORM carries a certain potential danger, since it means a sufficiently high value of reactivity, which can be introduced into the reactor due to the erroneous extraction of the CPS rods.

At the same time, at RBMK reactors, a low OZR value fatally affected the safety of the reactor. In order to maintain a constant reactor power (i.e., zero reactivity) with a small OZR, it is necessary to almost completely remove control rods from the core. Such a configuration (with removed rods) at RBMK was dangerous for several reasons ( ^[18] , pp. 49, 94–96):

• the spatial instability of the neutron field was enhanced, and it was difficult to ensure uniformity of energy release over the core;
• positive steam reactivity coefficient increased ;
• the effectiveness of emergency protection was significantly reduced, and in the first seconds after its operation, due to the " end effect " of the CPS rods, the power could even increase, instead of decreasing.

Station staff, apparently, knew only about the first of these reasons; neither the dangerous increase in the steam coefficient, nor the end effect was mentioned in the documents in force at that time. The staff was not aware of the true dangers associated with working with a low reactivity margin ( ^[18] , p. 54).

There is no rigid connection between the manifestation of the end effect and the operational reactivity margin. The threat of nuclear danger arises when a large number of CPS rods are in extreme upper positions. This is possible only if the ORM is small, but with the same ORM one can arrange the rods in different ways - so that a different number of rods will be in a dangerous position ^[27] .

There were no restrictions on the maximum number of completely removed rods in the regulation. OZR was not mentioned among the parameters important for safety, the technological regulations did not draw the attention of personnel to the fact that OZR is the most important parameter, the compliance of which determines the effectiveness of emergency protection. In addition, the project did not provide adequate means for measuring OCR. Despite the great importance of this parameter, there was no indicator on the remote control that would continuously display it. Typically, the operator received the last value in the printout of the calculation results on the station computer, twice an hour, or gave the task to calculate the current value, with delivery in a few minutes. Thus, OZR cannot be considered as an operatively controlled parameter,moreover, the error in its estimation depends on the shape of the neutron field (^[18] , p. 85-86).

Versions of the causes of the accident

There is no single version of the causes of the accident, which the entire expert community of experts in the field of reactor physics and technology would agree with. The circumstances of the accident investigation were such that then, and now, its causes and consequences have to be judged by specialists whose organizations directly or indirectly bear part of the responsibility for it. In this situation, a radical divergence of opinion is quite natural. It is also quite natural that under these conditions, in addition to the recognized "authoritative" versions, a lot of marginal ones appeared, based more on speculation than on facts.

Unified in authoritative versions is only a general idea of ​​the scenario of the accident. Its basis was an uncontrolled increase in reactor power. The destructive phase of the accident began when fuel elements collapsed from overheating of nuclear fuel(fuel rods) in a certain area in the lower part of the reactor core. This led to the destruction of the shells of several channels in which these fuel elements are located, and steam under a pressure of about 7 MPa got access to the reactor space, in which atmospheric pressure (0.1 MPa) is normally maintained. The pressure in the reactor space increased sharply, which caused further destruction of the reactor as a whole, in particular, the separation of the upper protective plate (the so-called “Scheme E”) with all channels fixed in it. The tightness of the reactor vessel (shell) and, together with it, the coolant circulation circuit (KMPTs) was broken, and the reactor core was dehydrated. In the presence of a positive vapor (void) reactivity effect of 4–5 β, this led to the acceleration of the reactor using instant neutrons and the observed large-scale destruction.

Versions fundamentally diverge on the question of which particular physical processes launched this scenario and what was the initial event of the accident:

• Did the initial overheating and destruction of fuel elements occur due to a sharp increase in reactor power due to the appearance of a large positive reactivity in it, or vice versa, the appearance of positive reactivity is a consequence of the destruction of fuel elements that occurred for any other reason ^[28] ?
• Was pressing the emergency protection button -5 immediately before an uncontrolled increase in power the initial event of the accident, or did pressing the button -5 have nothing to do with the accident ^[29] ? And then what should be considered as the initial event: the start of the run-out tests ( ^[18] , p. 73) or the non-silencing of the reactor during a power failure 50 minutes before the explosion ^[30] ?

In addition to these fundamental differences, the versions may diverge in some details of the scenario of the accident, its final phase (reactor explosion).

Of the main versions of the accident recognized by the expert community, only those in which the emergency process begins with a rapid uncontrolled increase in power followed by the destruction of fuel elements are considered more or less seriously ^[19] . The version ^[31] is considered to be the most probable , according to which “the initial event of the accident was the pressing of the -5 button under the conditions that developed in the RBMK-1000 reactor at its low power and when the PP rods were removed from the reactor in excess of the permissible amount” ( ^[18], from. 97). Due to the presence of an end effect with a steam reactivity coefficient of + 5β and in the state in which the reactor was located, emergency protection, instead of shutting down the reactor, starts the emergency process according to the above scenario. Calculations performed at different times by different groups of researchers show the possibility of such a development of events ^{[18] [32]}. This is also indirectly confirmed by the fact that in the case of “acceleration” of an instant neutron reactor due to a “belated” pressing of the AZ-5 button by the SIUR, a signal for its emergency stop would be generated automatically: if the period for doubling the power was exceeded, the maximum power level was exceeded and etc. Such events must have been preceded by a reactor explosion, and the reaction of the protection automation would have been mandatory and would certainly have outstripped the reaction of the operator. However, it is generally recognized that the first emergency protection signal was given by a button on the AZ-5 operator’s panel, which is used to shut down the reactor in any emergency and normal conditions. In particular, it was with this button that the 3rd Chernobyl power unit was stopped in 2000.

Records of the control system and witness statements confirm this version. However, not everyone agrees with this; there are calculations made at NIKIET that deny this possibility ^[9] .

The chief designer speaks of other versions of the initial uncontrolled increase in power, in which the reason for this is not the work of the reactor control system, but the conditions in the external circulation circuit of the KMPT created by the actions of the operating personnel. The initial events of the accident in this case could be:

• cavitation of the main circulation pump (MCP), which caused the MCP to shut off and to intensify the process of vaporization with the introduction of positive reactivity;
• cavitation on shut-off-control valves (SAM) of the reactor channels, which caused additional steam to enter the core with the introduction of positive reactivity;
• MCP shutdown by its own defenses, which caused the intensification of the process of vaporization with the introduction of positive reactivity.

Cavitation versions are based on computational studies performed at NIKIET, but, by the authors of these calculations, “detailed studies of cavitation phenomena have not been performed” ^[33] . The version of MCP shutdown as the initial accident event is not confirmed by the registered data of the monitoring system ( ^[18] , pp. 64–66). In addition, all three versions are criticized from the point of view that it is essentially not about the initial event of the accident, but about the factors contributing to its occurrence. There is no quantitative confirmation of the versions by calculations simulating the accident ( ^[18] , p. 84).

There are also various versions regarding the final phase of the accident - the actual explosion of the reactor.

Chemical explosion

It has been suggested that the explosion that destroyed the reactor was of a chemical nature, that is, it was an explosion of hydrogen that formed in the reactor at high temperature as a result of the steam-zirconium reaction and a number of other processes.

Steam explosion

There is a version that the explosion was exclusively steam. According to this version, all the damage was caused by the steam flow, having thrown out a significant part of graphite and fuel from the mine. And the pyrotechnic effects in the form of “fireworks of flying hot and burning fragments”, which were observed by eyewitnesses, are the result of “the occurrence of parocirconium and other chemical exothermic reactions” ^[17] .

Nuclear explosion version

According to the version proposed by the nuclear physicist, the liquidator of the consequences of the accident, Konstantin Checherov , the explosion, which had a nuclear nature, did not occur in the reactor shaft, but in the space of the reactor hall, where the reactor core together with the reactor cover were released by steam escaping from the broken channels ^[34] . This version agrees well with the nature of the destruction of the building structures of the reactor building and the absence of noticeable damage in the reactor shaft; it is included by the chief designer in his version of the accident ^[35]. The original version was proposed in order to explain the lack of fuel in the reactor shaft, subreactor and other rooms (the presence of fuel was estimated as not more than 10%). However, subsequent studies and estimates give reason to believe that about 95% of the fuel is located inside the “sarcophagus” built over the destroyed block ^[36] .

Alternate Versions

It is impossible to understand the causes of the Chernobyl accident without comprehending the intricacies of the physics of nuclear reactors and the technology of operation of nuclear power units with RBMK-1000. At the same time, the primary data on the accident were not known to a wide circle of specialists. In these conditions, in addition to the versions recognized by the expert community, many others appeared. First of all, these are versions proposed by specialists from other fields of science and technology. In all these hypotheses, the accident is the result of completely different physical processes than those that underlie the work of nuclear power plants, but well known to the authors from their professional activities.

Local earthquake

The version put forward by an employee of the Institute of Physics of the Earth of the Russian Academy of Sciences Eugene Barkovsky was widely known. This version explains the accident by a local earthquake ^[37] . The basis for this assumption is a seismic shock recorded at the time of the accident in the area of ​​the Chernobyl nuclear power plant. Proponents of this version claim that the shock was recorded before, and not at the time of the explosion (this claim is disputed ^{[38] [39]}), and the strong vibration that preceded the disaster could be caused not by processes inside the reactor, but by an earthquake. In addition, as geophysicists established, the 4th power unit itself stands at the site of the tectonic fault of earth plates. The reason that the neighboring third unit was not injured is the fact that the tests were carried out only at the 4th power unit. The employees of the nuclear power plants located on other units did not feel any vibrations. The REN-TV documentary investigation into the Chernobyl Doomed Nuclear Power Plant (2001) also mentions that in November 1985, the director of the Chernobyl NPP Viktor Bryukhanov in his letter to the USSR Institute of Geophysics said that during geodetic measurements that year excess displacement of the foundation plate of the 4th power unit of the station was detected^{[40] [41]} .

Intentional crime

There are conspiracy theological versions of the accident, which hint at the intentional fact of the actions that led to the accident. The most popular version is the recognition of the explosion at the Chernobyl nuclear power plant as a sabotage or even a terrorist act, the fact of which was concealed by the authorities ^[42] . Among diversion methods are called explosives placed under a reactor, traces of which were allegedly found on the surface of fuel mass melts; special fuel rods from highly enriched (weapons) uranium inserted into the active zone ^[43] ; sabotage using beam weapons mounted on an artificial Earth satellite, or the so-called remote geotectonic weapons ^[44] .

Data forgery

Boris Gorbachev, an employee of the Institute for Safety Problems at the NPP of the Academy of Sciences of Ukraine, proposed a version that is a free journalistic presentation of the generally accepted scenario of the accident with accusations by experts who investigated the accident and the NPP staff for forgery regarding the initial source data. According to Gorbachev, the explosion occurred due to the fact that the operators, when raising the power after its failure (at 00:28), removed too many control rods, doing this arbitrarily and uncontrollably until the moment of the explosion and not paying attention to the growing power ^{[39] [45]} . Based on the assumptions made, the author built a new chronology of events, however, this chronology contradicts reliable data and the physics of processes in a nuclear reactor ^{[9][11] [26] [46] [47]} .

Accident consequences

First hours

Directly during the explosion at the 4th power unit, one person died - the operator of the main circulation pumps Valery Hodemchuk (body not found). Another employee of the commissioning facility, Vladimir Shashenok, died of a spinal fracture and numerous burns at 6:00 on the same day in Pripyat medical unit No. 126. Subsequently, 134 employees of the Chernobyl nuclear power plant and members of rescue teams who were at the station during the explosion developed radiation sickness , 28 of them died in the next few months.

At 1:23 a.m., a fire warning signal came to the control panel of the on-duty HPV- 2 guard for the Chernobyl nuclear power plant. Three departments of the fire department, headed by internal affairs service lieutenant Vladimir Pravik, left for the station . The guard of the 6th city fire department, led by Lieutenant Viktor Kibenok, came out of Pripyat to help . Major Leonid Telyatnikov took charge of the fire , who received a very high dose of radiation and survived only thanks to a bone marrow transplant in England in the same year. His actions prevented the spread of fire. Additional reinforcements were called from Kiev and the surrounding areas (the so-called "number 3" - the highest fire difficulty number).

Of the protective equipment, the firefighters had only a tarpaulin robe (combat), mittens, and a helmet. The links of the gas and smoke protection service were in gas masks KIP-5. Due to the high temperature, firefighters removed them in the first minutes. By 4 a.m., the fire was localized on the roof of the engine room, and extinguished by 6 a.m. In total, 69 people and 14 pieces of equipment took part in putting out the fire. The presence of a high level of radiation was reliably established only at 3:30, because of the two available devices at 1000 R / h, one failed, and the other was inaccessible due to blockages. Therefore, in the first hours of the accident, the real levels of radiation in and around the unit were unknown. The state of the reactor remained unclear; there was a version that the reactor was intact and needed to be cooled.

Firefighters prevented the fire from spreading to the third block (the 3rd and 4th power units have uniform transitions). Instead of a fire-resistant coating, as required by the instructions, the roof of the engine room was flooded with ordinary combustible bitumen . By about 2 o’clock in the morning the first firemen appeared. They began to show weakness, vomiting, " nuclear tanning ." They were assisted on the spot, at the station’s first-aid post, and then transferred to MSCh-126. By the morning of April 27, the radiation background in MSC-126 was extremely high, and in order to somehow reduce it, the medical staff transferred all the firefighters' clothes to the basement of the medical unit. On the same day, the first group of 28 victims was sent by plane to Moscow, to the 6th radiological hospital. Virtually no fire truck drivers were affected.

In the first hours after the accident, many apparently did not realize how badly the reactor was damaged, so an erroneous decision was made to provide water to the reactor core to cool it. This required work in areas with high radiation. These efforts turned out to be futile, as both the pipelines and the core itself were destroyed. Other actions of the station personnel, such as extinguishing fires in the premises of the station, measures aimed at preventing a possible explosion, on the contrary, were necessary. Perhaps they prevented even more serious consequences. In carrying out these works, many station employees received large doses of radiation, and some even fatal.

Information and evacuation of the population

	Announcement of evacuation from Pripyat
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The first report of the Chernobyl accident appeared in the Soviet media on April 27, 36 hours after the disaster. The announcer of the Pripyat radio broadcasting network reported on the collection and temporary evacuation of residents of the city ^[48] .

After assessing the extent of radioactive contamination, it became clear that the evacuation of the city ​​of Pripyat , which was carried out on April 27, would be required . In the first days after the accident, the population of the 10-kilometer zone was evacuated, and in the following days, other settlements of the 30-kilometer zone . It was forbidden to bring things, children's toys and the like, many were evacuated in home clothes. In order not to inflame the panic, it was reported that the evacuees would return home in three days. Pets were not allowed to take with them.

Safe routes of movement of columns of the evacuated population were determined taking into account already obtained data from radiation intelligence. Despite this, on 26 and 27 April, residents were not warned of the danger and did not give any recommendations on how to behave in order to reduce the effects of radioactive contamination.

Only on April 28, at 21:00, TASS reported: “An accident occurred at the Chernobyl nuclear power plant. One of the nuclear reactors is damaged. Measures are being taken to eliminate the consequences of the accident. The victims are assisted. A government commission " ^[49] .

While many foreign media spoke about a threat to people's lives, and on TV screens a map of air flows in Central and Eastern Europe was shown, in Kiev and other cities of Ukraine and Belarus festive demonstrations and festivities dedicated to May Day were held . The demonstration in Kiev was organized at the personal direction of CPSU Secretary General Mikhail Gorbachev ^{[50] [51]} . Persons responsible for concealing information subsequently explained their decision by the need to prevent panic among the population ^[52] .

On May 1, 1986, the regional Council of People’s Deputies decided to allow foreigners to leave the Gomel Region only after a medical examination, “If they refuse to have a physical examination, it is enough to receive a receipt that (...) there are no claims against the Soviet authorities have ” ^[53] .

Disaster Management

To eliminate the consequences of the accident, a government commission was created, the chairman - deputy chairman of the Council of Ministers of the USSR B. E. Shcherbin . From the institute that developed the reactor, inorganic chemist Academician V. A. Legasov entered the commission . As a result, he worked at the scene of the accident for 4 months instead of the prescribed two weeks. It was he who calculated the possibility of application and developed the composition of the mixture ( boron-containing substances, lead and dolomites), which from the very first day threw the reactor zone from helicopters to prevent further heating of the reactor residues and to reduce emissions of radioactive aerosols into the atmosphere. It was also he who, having traveled directly to the reactor on an armored personnel carrier, determined that the readings of the neutron sensors about the ongoing nuclear reaction were unreliable, since they react to powerful gamma radiation. The analysis of the ratio of iodine isotopes showed that in fact the reaction stopped. The first ten days, Major General Aviation N. T. Antoshkin directly supervised the actions of personnel to dump the mixture from helicopters ^[54] .

To coordinate the work, republican commissions were also created in the Byelorussian SSR, the Ukrainian SSR and the RSFSR, various departmental commissions and headquarters. In the 30-kilometer zone around the Chernobyl nuclear power plant, experts began to arrive, sent to work on the emergency unit and around it, as well as military units - both regular and made up of urgently called up reservists. All these people were later called " liquidators ." They worked in the danger zone in shifts: those who had collected the maximum permissible dose of radiation left, and others came in their place. Most of the work was carried out in 1986-1987, about 240 thousand people took part in them. The total number of liquidators was, including subsequent years, about 600 thousand.

In all savings banks of the country, an “904 account” was opened for donations from citizens, which received 520 million rubles in six months. Among the donors was singer Alla Pugacheva , who gave a charity concert at the Olimpiyskiy and a recital in Chernobyl for the liquidators ^{[55] [56]} .

In the early days, the main efforts were aimed at reducing radioactive emissions from the destroyed reactor and preventing even more serious consequences. For example, there were fears that due to the residual heat in the fuel remaining in the reactor, the core of the nuclear reactor would melt . Measures were taken to prevent melt from entering the soil under the reactor. In particular, a 136-meter tunnel under the reactor was dug by miners during the month. To prevent pollution of groundwater and the Dnieper River in the soil around the station, a protective wall was built, the depth of which in some places reached 30 meters. Also, within 10 days, engineering forces dumped dams on the Pripyat River.

Then, work began on cleaning the territory and burying the destroyed reactor. Around the 4th block, a concrete “ sarcophagus ” (the so-called “Shelter” object) was built. Since it was decided to launch the 1st, 2nd and 3rd blocks of the station, the radioactive debris scattered across the territory of the nuclear power plant and on the roof of the machine room were removed inside the sarcophagus or concreted. Decontamination was carried out in the premises of the first three power units . The construction of the sarcophagus was begun in July and completed in November 1986. During construction work on October 2, 1986, near the 4th power unit, catching on a crane cable three meters from the engine room, the Mi-8 helicopter crashed , and its crew of 4 people died.

According to the Russian State Medical and Dosimetric Register, over the past years among Russian liquidators with radiation doses above 100 mSv (10 rem) - this is about 60 thousand people - several dozen deaths could be associated with radiation. In just 20 years in this group, from all causes not related to radiation, approximately 5,000 liquidators have died.

In addition to “external” exposure, the liquidators were in danger due to “internal” exposure caused by inhalation of radioactive dust. The proximity of the radiation source to the tissues and the long duration of exposure (many years after the accident) make “internal” exposure dangerous even with relatively low dust radioactivity, and this danger is extremely difficult to control. The main way radioactive substances enter the body is through inhalation ^[57] . To protect against dust, Lepestok respirators and other personal respiratory protection equipment were widely used ^[58] , but due to the significant leakage of unfiltered air at the place of touching the mask and the Petals face, they were ineffective, which could lead to a strong "internal" exposure of some of the liquidators.

Legal implications

The world nuclear energy as a result of the Chernobyl accident was dealt a serious blow. From 1986 to 2002, not a single new nuclear power plant was built in North America and Western Europe , due to both public pressure and the fact that insurance premiums increased significantly and the profitability of nuclear power decreased .

In the USSR, the construction and design of 10 new nuclear power plants was mothballed or stopped, and the construction of dozens of new power units at existing nuclear power plants in different regions and republics was frozen.

The legislation of the USSR, and then Russia, enshrined the responsibility of persons who intentionally hide or do not bring to the public the consequences of environmental disasters, technological accidents. Information related to the environmental safety of places cannot now be classified as secret.

According to Article 10 of the Federal Law of February 20, 1995 No. 24- “On Information, Informatization and Protection of Information” emergency information, environmental, meteorological, demographic, sanitary and epidemiological and other information necessary to ensure the safe functioning of production facilities, safety citizens and the general population, are open and cannot relate to information with limited access ^[59] .

In accordance with Article 7 of the Law of the Russian Federation dated July 21, 1993 No. 5485-1 “On State Secrets”, information on the state of the environment is not subject to classification as a state secret ^[60] .

The current Criminal Code of the Russian Federation in article 237 provides for the responsibility of persons for concealing information on circumstances that create a danger to human life or health ^[61] :

Article 237. Concealment of information on circumstances creating a danger to human life or health

1. Concealment or distortion of information about events, facts or phenomena that endanger the life or health of people or the environment, committed by a person who is obliged to provide the population and bodies authorized to take measures to eliminate such a danger with the information indicated, are punishable by a fine of up to three hundred thousand rubles, or in the amount of the wage or other income of the convicted person for a period of up to two years or by deprivation of liberty for a term of up to two years with the deprivation of the right to occupy certain positions or engage in certain activities for a period of up to three years or without it.
2. The same acts, if committed by a person holding a public office of the Russian Federation or a public office of a constituent entity of the Russian Federation, as well as by the head of a local government body or if as a result of such acts harmed human health or other serious consequences, are punished with a fine of one hundred thousand to five hundred thousand rubles, or in the amount of the wage or other income of the convicted person for a period of one year to three years, or by deprivation of liberty for a term of up to five years with the deprivation of the right to occupy certain positions or engage in certain activities for a period of up to three years or without it.

Radioactive release

Before the accident, the fourth unit reactor contained 180-190 tons of nuclear fuel ( uranium dioxide ). According to estimates that are currently considered the most reliable, from 5 to 30% of this amount was released into the environment. Some researchers dispute this data, referring to available photographs and observations of eyewitnesses, which show that the reactor is almost empty. However, it should be borne in mind that the volume of 180 tons of uranium dioxide is only an insignificant part of the reactor volume. The reactor was mainly filled with graphite. In addition, part of the contents of the reactor melted and moved through faults at the bottom of the reactor vessel beyond.

In addition to fuel, in the core at the time of the accident, fission products and transuranium elements  — various radioactive isotopes accumulated during reactor operation — were contained . They represent the greatest radiation hazard. Most of them remained inside the reactor, but the most volatile substances were released into the atmosphere, including ^{[62] [63]} :

• 100% noble gases ( krypton and xenon ) contained in the reactor;
• from 50% to 60% of iodine in gas and aerosol forms;
• up to 60% tellurium and up to 40% cesium in the form of aerosols .

The total activity of radionuclides released into the environment, according to various estimates, amounted to 14⋅10 ¹⁸ Bq (approximately 38⋅10 ⁷ Ci , for comparison: in the explosion of a nuclear charge with a power of 1 Mt , ≈ 1.5⋅10 ⁵ Ci of strontium- 90 and 1⋅10 ⁵ cesium-137), including ^{[5] [64] [65] [66]} :

Isotope (radiation / T½ )	Activity, P Bq	During decay, it forms	Isotope (radiation / T½)	Activity, PBC	During decay, it forms
xenon-133 (β-, γ- / 5.3 days.)	6510	cesium-133 (st.)	cesium-134 (β- / 2.06 years)	44.03	barium-134 (Art.)
neptunium-239 (β-, γ- / 2.4 days)	1684.9	plutonium-239 (α-, γ- / 24113 years) ↓	ruthenium-106 (β- / 374 days)	30.1	rhodium-106 (β-, γ- / 29.8 sec) ↓
		uranium-235 (α-, γ- / 7⋅10 8 years) ↓			palladium-106 (st.)
		thorium-231 (β-, γ- / 25.5 h) ↓ ...	krypton-85 (β-, γ- / 10.7 years)	28	rubidium-85 (st.)
iodine-131 (β-, γ- / 8 days.)	1663.2-1800	xenon-131 (Art.)	strontium-90 (β- / 28.8 years)	8.05-10	yttrium-90 (β-, γ- / 64.1 h) ↓
tellurium-132 (β-, γ- / 3.2 days)	407.7	iodine-132 (β-, γ- / 2.3 h) ↓			zirconium-90 (st.)
		xenon-132 (Art.)	plutonium-241 (α-, β- / 14.4 years)	5.94	americium-241 (α-, β-, γ- / 432.6 years) +
cerium-141 (β-, γ- / 32.5 days)	194.25	praseodymium-141 (st.)			+ uranium-237 (β- / 6.8 days) ↓
barium-140 (β-, γ- / 12.8 days)	169.96	lanthanum-140 (β- / 40.2 h) ↓			Neptunium-237 (α- / 2,1⋅10 6 years) ↓ ...
		cerium-140 (Art.)	Curium-242 (α- / 163 days)	0.946	plutonium-238 (α- / 87.7 years) ↓
ruthenium-103 (β- / 39.3 days)	169.65	rhodium-103 m (β-, γ- / 56 min) ↓			uranium-234 (α- / 2.5⋅10 5 years) ↓
		palladium-103 (γ- / 17 days) ↓			thorium-230 (α- / 75380 years) ↓ ...
		rhodium-103 (st.)	plutonium-240 (α-, γ- / 6564 years)	0.0435	uranium-236 (α- / 2,3⋅10 7 years) ↓
zirconium-95 (β-, γ- / 64 days.)	163.8	niobium-95 (β- / 35 days) ↓			thorium-232 (α- / 1,4⋅10 10 years) ↓ ...
		molybdenum-95 (st.)	plutonium-239 (α-, γ- / 24113 years)	0,0304	uranium-235 (α-, γ- / 7⋅10 8 years) ↓
cerium-144 (β-, γ- / 285 days)	137.2	praseodymium-144 (β- / 17.5 min) ↓			thorium-231 (β-, γ- / 25.5 h) ↓
		neodymium-144 (γ- / 2,3⋅10 15 years) ↓ ...			protactinium-231 (α- / ~ 32500 years) ↓ ...
cesium-137 (β-, γ- / 30.17 years)	82.3—85	barium-137 (st.)	plutonium-238 (α- / 87.7 years)	0.0299	uranium-234 (α- / 2.5⋅10 5 years) ↓
strontium-89 (β- / 50.6 days)	79.2	yttrium-89 (art.)			thorium-230 (α- / 75380 years) ↓ ...

• Art. - stable non-radioactive isotope at the end of the isotope fission chain ;
• ↓, ↓ ... - further decay of the unstable isotope formed during the radioactive decay of the previous unstable isotope (alternately from top to bottom) .

Territory pollution

As a result of the accident, about 5 million hectares of land was taken out of agricultural circulation, a 30-kilometer exclusion zone was created around the nuclear power plant, hundreds of small settlements were destroyed and buried (buried by heavy machinery), as well as personal vehicles and motor vehicles of evacuated residents, which were also contaminated and people were not allowed to leave on it. As a result of the accident, it was decided to abandon the operation of the Duga No. 1 radar station , which was to become one of the main elements of the USSR missile defense ^[67] .

Over 200 thousand km² has been contaminated. Radioactive substances spread in the form of aerosols, which gradually deposited on the surface of the earth. Noble gases scattered in the atmosphere and did not contribute to the pollution of the regions adjacent to the station. The pollution was very uneven, it depended on the direction of the wind in the first days after the accident. The most affected areas are in the immediate vicinity of the Chernobyl nuclear power plant: the northern regions of the Kiev and Zhytomyr regions of Ukraine, the Gomel region of Belarus and the Bryansk region of Russia. Radiation affected even some regions far removed from the accident site, for example, the Leningrad Region, Mordovia and Chuvashia - there were radioactive fallout. Most of the strontium and plutonium fell within 100 km of the station, since they were mainly contained in larger particles.Iodine and cesium spread to a wider area.

Decree of the Government of the Russian Federation “On approval of the list of settlements located within the boundaries of radioactive contamination zones due to the Chernobyl disaster” of October 8, 2015, the Decree of the Government of the Russian Federation of December 18, 1997 No. 1582 “On approval of the list of settlements located in the boundaries of the zones of radioactive contamination due to the disaster at the Chernobyl nuclear power plant ”and Decree of the Government of the Russian Federation of April 7, 2005 No. 197“ On changing the list of settlements located within the borders of the zones of radioactive contamination due to the disaster at the Chernobyl nuclear power plant ” ^[68]and the borders of the zones of radioactive contamination were revised “taking into account changes in the radiation situation, including as a result of the implementation of a set of protective and rehabilitation measures in 1986-2014,” as a result, a number of settlements “declined” in status, having lost a number of benefits and payments provided for The Law of the Russian Federation “On the social protection of citizens exposed to radiation as a result of the Chernobyl disaster” ^[69] . In total, 558 settlements were excluded from the zones of radioactive contamination in Russia, and 383 settlements were transferred to zones with a lower level of radioactive contamination ^[70] .

From the point of view of the impact on the population in the first weeks after the accident, radioactive iodine, having a relatively short half-life (eight days), and tellurium were the most dangerous . Currently (and in the coming decades) the greatest danger is strontium and cesium isotopes with a half-life of about 30 years. The highest concentrations of cesium-137 are found in the surface soil layer, from where it enters plants and fungi. Animals are also contaminated, including the insects that feed on them. The radioactive isotopes of plutonium and americium can persist in the soil for hundreds, and possibly thousands of years, but their number is small ( ^[5], from. 22). The amount of americium-241 will increase due to the fact that it is formed during the decay of plutonium-241 ^[71] .

In cities, the bulk of hazardous substances accumulated on flat surface areas: on lawns, roads, roofs. Under the influence of wind and rains, as well as as a result of human activities, the degree of pollution has greatly decreased, and now the radiation levels in most places have returned to the background values. In agricultural areas, in the first months, radioactive substances were deposited on the leaves of plants and on grass, so herbivores were contaminated. Then the radionuclides, along with rain or fallen leaves, fell into the soil, and now they enter agricultural plants, mainly through the root system. Pollution levels in agricultural areas have declined significantly, but in some regions the amount of cesium in milk may still exceed acceptable levels. This applies, for example, toGomel and Mogilev regions in Belarus, Bryansk region in Russia, Zhytomyr and Rivne region in Ukraine.

Forests have been heavily polluted. Due to the fact that cesium is constantly recycled in the forest ecosystem without being removed from it, the levels of contamination of forest products, such as mushrooms, berries and game, remain dangerous. The level of pollution of rivers and most lakes is currently low, but in some “closed” lakes, of which there is no runoff, the concentration of cesium in water and fish over the next decades can be dangerous.

Pollution was not limited to a 30-kilometer zone. An increased content of cesium-137 in lichen and deer meat was noted in the Arctic regions of Russia, Norway, Finland and Sweden.

July 18, 1988 in the territory of Belarus, exposed to pollution, the Polessky State Radiation and Ecological Reserve was created ^[72] . Observations showed that the number of mutations in plants and animals increased, but not significantly, and nature successfully copes with their consequences (by natural selection , that is, removal (death) of defective organisms from the population ). On the other hand, the removal of anthropogenic impact had a positive effect on the ecosystem of the reserve, which significantly exceeded the negative effects of radiation. As a result, nature began to recover rapidly, populations grewanimals, the diversity of vegetation species has increased ^{[73] [74]} .

The impact of the accident on human health

Lack of timeliness, incompleteness and inconsistency of official information about the disaster gave rise to many independent interpretations. Sometimes victims of the tragedy are considered not only citizens who died immediately after the accident, but also residents of the surrounding areas who went to the May Day demonstration, not knowing about the accident ^[75] . With such a calculation, the Chernobyl disaster significantly exceeds the atomic bombing of Hiroshima in the number of victims ^[76] .

According to the World Health Organization , presented in 2005, as a result of the Chernobyl accident, up to a total of 4,000 people could die in the long run ^[77] .

Greenpeace and Doctors Against Nuclear War International claim that as a result of the accident, only among the liquidators, tens of thousands of people died, 10 thousand cases of malformations in newborns, 10 thousand cases of thyroid cancer were recorded and another 50 thousand are expected ^[78] .

There is an opposite point of view, referring to 29 recorded cases of death from acute radiation sickness as a result of an accident (station employees and firefighters who took the first blow) and denying the development of chronic radiation sickness subsequently by anyone ^[79] .

The spread in official estimates is less, although the number of victims of the accident can be determined only approximately. In addition to the deceased nuclear power plant workers and firefighters, they include sick military personnel and civilians involved in the aftermath of the accident , and residents of areas exposed to radioactive contamination. Determining which part of the disease was the result of the accident is a very difficult task for medicine and statistics . It is believed that most of the deaths associated with exposure to radiation were or will be caused by cancer ^[5] .

The Chernobyl Forum , under the auspices of the UN , including its organizations such as the IAEA and WHO, in 2005 published a report that analyzed numerous scientific studies of the impact of accident-related factors on the health of liquidators and the public. The findings in this report, as well as in the less detailed review of the Chernobyl Heritage published by the same organization, differ significantly from the above estimates. The number of possible victims to date and in the coming decades is estimated at several thousand people. It is emphasized that this is only an estimate in order of magnitude, since due to the very small radiation doses received by the majority of the population, it is very difficult to single out the effect of exposure to radiation against the background of random fluctuations in morbidity and mortality and other factors not directly related to exposure. Such factors include, for example, a decline in living standards after the collapse of the USSR,which led to a general increase in mortality and a decrease in life expectancy in the three countries most affected by the accident, as well as a change in the age composition of the population in some heavily polluted areas (part of the young population left)^[80] .

It is also noted that a slightly increased incidence rate among people who did not directly participate in the liquidation of the accident, but who were relocated from the exclusion zone to other places, is not directly related to radiation (in these categories a slightly increased incidence of the cardiovascular system, metabolic disorders, and nervous diseases and other diseases not caused by radiation), but caused by stresses associated with the fact of resettlement, loss of property, social problems, fear of radiation. Including for these reasons, from the fall of 1986 to the spring of 1987, more than 1,200 people returned to the exclusion zone .

Given the large population living in areas affected by radioactive contamination, even small discrepancies in assessing the risk of disease can lead to a large difference in estimating the expected number of cases. Greenpeace and several other public organizations insist on the need to take into account the impact of the accident on public health in other countries, however, even lower doses to the population in these countries make it difficult to obtain statistically reliable results and make such estimates inaccurate.

Radiation doses

Average doses received by different categories of the population ^[5]

Category	Period	Number of people	Dose ( mSv )
Liquidators	1986-1989	600,000	about 100
Evacuated	1986	116,000	33
Residents of areas with "strict control"	1986-2005	270,000	more than 50
Residents of other polluted areas	1986-2005	5,000,000	10-20

The highest doses were received by about 1,000 people who were near the reactor at the time of the explosion and who took part in emergency operations in the first days after it. These doses ranged from 2 to 20 gray (Gy) and in some cases were fatal.

Most of the liquidators who worked in the danger zone in subsequent years, and local residents received relatively small doses of radiation to the whole body. For liquidators, they averaged 100 mSv , although sometimes they exceeded 500. Doses received by residents evacuated from heavily contaminated areas sometimes reached several hundred millisievert, with an average value of 33 mSv. Doses accumulated over the years after the accident are estimated at 10-50 mSv for most residents of the contaminated zone, and up to several hundred for some of them.

Some of the liquidators, in addition to exposure from external sources of radiation, could also be exposed to “internal” exposure - from radioactive dust deposited in the respiratory organs. The respirators used were not always effective enough.

For comparison, residents of some regions of the Earth with an increased natural background (for example, in Brazil , India , Iran and China ) receive radiation doses equal to about 100-200 mSv for 20 years ^[5] .

Many local residents in the first weeks after the accident ate foods (mainly milk) contaminated with radioactive iodine-131. Iodine accumulated in the thyroid gland, which led to large doses of radiation to this organ, in addition to the dose to the whole body obtained due to external radiation and radiation of other radionuclides that got into the body. For residents of Pripyat, these doses were significantly reduced (estimated at 6 times) due to the use of iodine-containing drugs. In other areas, such prevention was not carried out. The doses received ranged from 0.03 to several Gy.

Currently, most residents of the contaminated area receive less than 1 mSv per year in excess of the natural background ^[5] .

In the European part of Russia to this day (2009), the levels of radionuclides , in particular marker strontium-90, are higher than the background levels , but lower than those at which intervention is required to reduce according to NRB-99 /2009 ^[81] .

Acute radiation sickness

134 cases of acute radiation sickness among people performing emergency work in the fourth unit were confirmed . In many cases, radiation sickness was complicated by radiation burns of the skin caused by β-radiation . Out of this number of people, during 1986, 28 people died from radiation sickness ^[82] . Two more people died during the accident for reasons other than radiation, and one died, presumably from coronary thrombosis. In 1987-2004, another 19 people died, but their death was not necessarily caused by radiation sickness ^[5] .

Oncological diseases

The thyroid gland  is one of the organs most at risk of malignant tumors as a result of radioactive contamination, because it accumulates iodine-131; especially high risk for children. In 1990-1998, more than 4000 cases of thyroid cancer were registered among those who were less than 18 years old at the time of the accident. Given the low probability of illness at this age, some of these cases are considered a direct result of exposure. Experts at the UN Chernobyl Forum believe that with timely diagnosis and proper treatment, this disease does not pose a very great danger to life, but at least 15 people have already died from it. Experts believe that the number of thyroid cancer diseases will continue to grow for many years ^[80].

Some studies show an increase in the incidence of leukemia and other types of malignant tumors (except leukemia and thyroid cancer ) in both liquidators and residents of contaminated areas. These results are contradictory and often statistically unreliable; no convincing evidence of an increase in the risk of these diseases directly related to the accident was found. However, the monitoring of a large group of liquidators conducted in Russia revealed an increase in mortality by several percent. If this result is correct, it means that among the 600 thousand people exposed to the highest radiation doses, the death rate from malignant tumors will increase as a result of the accident by about 4 thousand people, in addition to about 100 thousand cases caused by other causes^[80] .

From experience gained earlier, for example, when observing victims of the atomic bombings of Hiroshima and Nagasaki, it is known that the risk of leukemia decreases several decades after exposure ^[80] . In the case of other types of malignant tumors, the situation is the opposite. During the first 10-15 years, the risk of getting sick is small, and then increases. However, it is not clear how applicable this experience is, since most of the victims of the Chernobyl accident received significantly lower doses.

Hereditary diseases

According to the report of the Chernobyl Forum ^{[83] [84]} , published statistical studies do not contain convincing evidence of a high level of congenital abnormalities and high infant mortality in contaminated areas.

An increase in the number of congenital pathologies was found in various regions of Belarus between 1986 and 1994, however, it was approximately the same both in contaminated and clean areas. In January 1987, an unusually large number of cases of Down syndrome were recorded , but there was no subsequent trend towards an increase in incidence.

Child mortality is very high in all three countries affected by the Chernobyl accident. After 1986, mortality declined both in contaminated and clean areas. Although the decrease in the contaminated areas was on average slower, the scatter of values ​​observed in different years and in different areas does not allow us to speak of a clear trend. In addition, in some of the contaminated areas, child mortality before the accident was significantly lower than average. In some of the most heavily polluted areas there has been an increase in mortality. It is unclear whether this is due to radiation or other reasons - for example, low living standards in these areas or poor quality of care.

Additional studies are being carried out in Belarus, Russia and Ukraine, the results of which were not yet known at the time of publication of the report of the Chernobyl Forum.

Other diseases

A number of studies have shown that liquidators and residents of contaminated areas are at increased risk of various diseases, such as cataracts , cardiovascular diseases, and decreased immunity ^[80] . The Chernobyl Forum experts concluded that the relationship between cataract diseases and radiation after the accident has been established quite reliably. For other diseases, more research is needed with a careful assessment of the effects of competing factors.

The fate of the station

After the accident at the 4th power unit, the power plant was suspended due to a dangerous radiation situation; the 5th and 6th power units planned for commissioning were never completed. However, already in October 1986, after extensive decontamination of the territory and the construction of the “sarcophagus”, the 1st and 2nd power units were re-commissioned; in December 1987, the work of the 3rd power unit was resumed. In 1991, a fire occurred at the 2nd power unit caused by faulty insulation of the turbine; after this accident, the 2nd power unit was shut off and closed. Nevertheless, over the following years, the two remaining power units of the station - the 1st and 3rd - continued to operate and generate electricity. In 1995, the Ukrainian government signed a Memorandum of Understanding with the governments of the G7 countries”And the European Commission : a station closure program has been prepared. The 1st power unit was shut down on November 30, 1996, and the 3rd on December 15, 2000 ^{[85] [86]} .

The initial reinforced concrete sarcophagus, hastily built in 1986 - “ Shelter ” - began to deteriorate over time, and in the 2010s a second sarcophagus was built, this time steel - “ New Safe Confinement ”. The French Consortium Novarka, a joint venture between Vinci and Bouygues ^[87] , was involved in the construction, financed by an international fund managed by the European Bank for Reconstruction and Development .. Construction started in 2010 was delayed several times, including due to lack of funding; in the end, confinement cost more than 1.5 billion euros. An arched structure was erected next to the old sarcophagus and in November 2016 was pulled onto the reactor building with jacks - thereby the New Safe Confinement enclosed both the destroyed reactor and the old sarcophagus around it ^{[88] [89]} .

In accordance with the National Program of Ukraine (dated January 15, 2009) on the decommissioning of the Chernobyl nuclear power plant ^[90] and the transformation of the Shelter into an environmentally friendly system, the process will be carried out in several stages:

1. Decommissioning (preparatory phase for decommissioning) is the stage during which nuclear fuel will be removed and transferred to the spent nuclear fuel storage facility for long-term storage. The current stage, during which the main task is carried out, which determines the duration of the stage, is the extraction of nuclear fuel from power units. The deadline is not earlier than 2014.
2. Final closure and conservation of reactor facilities. At this stage, the reactors and the most radiation-contaminated equipment will be mothballed (tentatively until 2028).
3. The exposure of the reactor plants during the period during which a natural decrease in radioactive radiation should occur to an acceptable level (tentatively until 2045).
4. Dismantling of reactor plants. At this stage, the equipment will be dismantled and the site cleaned up in order to maximize the removal of restrictions and regulatory control (tentatively until 2065). ^[91]

In popular culture

Documentaries

• “Chernobyl. Chronicle of Hard Weeks ”- a film shot by the director of Ukrkinochroniki Vladimir Shevchenko in 1986, contains a newsreel of eliminating the consequences of the Chernobyl explosion.
• “The Chernobyl Bell” is the first feature film about the Chernobyl accident, shot in May-September 1986. Contains evidence of people directly involved in the tragedy. He is listed in the Guinness Book of Records as a film that has been shown in all countries of the world where there is television ^{[92] [93]} .
• "The area of ​​action - Chernobyl" is a film shot by the film studio of the USSR Ministry of Defense in 1987.
• The TV show “Hour X”  - in the 1st episode filmed in 2004, the hour before the accident at the nuclear power plant is described in detail.
• “ Seconds to Disaster ” - Season 1, Issue 7. Contains an interview with the last surviving employee of the 4th power unit, a participant in the experiment, a senior unit control engineer, Boris Stolyarchuk.
• Surviving Disaster: Chernobyl Nuclear Disaster (Surviving Disaster: Chernobyl Nuclear Disaster) is a documentary, a story told from the perspective of scientist Valery Legasov , who later committed suicide, filmed by the BBC , in 2006.
• “Battle for Chernobyl” is a 2005 production of the Discovery Channel .
• “Chernobyl. Chronicles of Silence ”- a 2006 film produced by the“ History ”television channel; more than 50 direct participants and witnesses of the accident were involved in the filming of the film.
• "Chernobyl: 30 years later" - a film produced in the UK in 2015.
• “Returning to Chernobyl” - “בחזרה לצ'רנוביל” - a film made about the accident and Chernobyl tow trucks in Israel and Ukraine by the Israeli state channel “Kan-11” in 2020 ^[94] .

Feature films and television series

• “ Decay ” is a feature film directed by Mikhail Belikov in 1989-1990. about the accident at the Chernobyl nuclear power plant and its consequences.
• "Wolves in the Zone" - a film from the Minsk studio "Impulse", shot in 1990
• “ Chernobyl. Last Warning ”- a television movie co-produced by the USA and the USSR, filmed in 1991
• "Tomorrow. Nuclear Princess ”is a feature film of the famous Soviet director Alexander Pankratov, shot in 1991.
• “Black Stork” - a film by Victor Turov, based on the novel by Viktor Kozko “Save and have mercy on us, the black angel”, shot by Belarusfilm studio in 1993
• " Aurora " - a film director Oksana Bayrak, filmed in 2006. Aurora is a pupil of an orphanage on the outskirts of Pripyat, who dreams of becoming a ballerina. During the Chernobyl disaster, the girl receives a huge dose of radiation. The only chance of survival is an expensive operation in the United States. Aurora is sent to America, where in the hospital she meets her idol, the ballet star Nick Astakhov.
• “The Door” is a short film of 2008, the plot is based on the chapter “A Monologue on a Lifetime Written on the Doors” of the book “ Chernobyl Prayer ” by Svetlana Aleksievich.
• “ Saturday ” is a feature film by Alexander Mindadze 2011, which takes place throughout the day before and during the accident at the nuclear power plant.
• “ Land of Oblivion ” is a 2011 French-Ukrainian film.
• “ Forbidden Zone ” is an American horror film by Bradley Parker, released in 2012.
• " Butterflies " - Ukrainian chetyrohseriyny mini-series published in 2013. 10-grader Alya Shirokova and her older sister Maryana, who works as a doctor, go on weekends from the night of April 25 to 26, 1986 from Kiev to Pripyat to relatives. Before their eyes, an explosion occurs at the 4th block of the Chernobyl nuclear power plant.
• “ Chernobyl: Exclusion Zone ” is a Russian mystical series whose heroes are trying to prevent an accident, after which the accident happens in America, and Pripyat becomes a developed city. The first season was shown in 2014
• “ Voices of Chernobyl ” is a dramatic film of 2016, shot by Paul Kruchten based on the book “ Chernobyl Prayer ” by Svetlana Aleksievich.
• “ Chernobyl ” - a mini-series created by the American channel HBO together with the British television network Sky, is shown in May-June 2019.
• “ Chernobyl: The Abyss ” is a film directed by Danila Kozlovsky (Russia, 2020).

Music Clips

• Chernobyl is mentioned in the composition “Radioactivity” of the album “ The Mix ” of the German instrumental group “ Kraftwerk ”.
• Adriano Celentano released a song in 2012 called “Sognando Chernobyl”.
• In 2016, ONUKA released the mini-album VIDLIK , the theme of which is related to the Chernobyl disaster. In composition "1986", recordings of negotiations between dispatchers of fire units were used.
• The song of the Russian alternative group [AMATORY] "Black" from the album "DOOM".
• The song Noize MC "26.04".
• The following videos were shot in Pripyat:

• The video for the song “Sweet People” (2010) by Ukrainian singer Alyosha . (In the song, the girl urges people to protect our planet.)
• Clip “ Marooned ” (2014) by Pink Floyd ( frames starting at 2:29) 
•  Clip for the song “Life Is Golden” (2018) by the British band Suede

• The British rapper Example shot in the exclusion zone a video clip for the song “What We Made”, in which he talks about the human impact on the environment.
• The British electronic project Delphic shot a clip for one of the songs in the exclusion zone. The director did not concentrate on abandoned places, but on residents who continued to live near the Pripyat and in the settlements adjacent to the Chernobyl zone.

Games

• The events surrounding the accident at the Chernobyl nuclear power plant were used in the artistic concept of the STALKER series of computer games
• Chernobylite , a game from the Polish studio The Farm 51 , its actions also take place in the exclusion zone

see also

• The Kyshtym accident (1957) is the largest radiation accident (6th level on the international scale of nuclear events ) in the world before the accident at the Chernobyl nuclear power plant.
• The accident at the Fukushima-1 nuclear power plant (2011) is an accident in Japan , like the Chernobyl accident , estimated at the maximum 7th level on the international scale of nuclear events.
• Pripyat (river)

Notes

Literature

additional literature

• Kostenetsky, M.I. Chernobyl-1986: How it was // Melitopol Journal of Local Lore. - 2016. - No. 7. - S. 3-9.
• Chernobyl Report: Photo Album / Ed. Guskova T.V. - M  .: Planet, 1988 .-- 142 p. - ISBN 5-85250-033-X .
• Rossinskaya, S. V. Chernobyl: how was it? Mystery of the 20th century: literary evening at the Foliant library of the MUK TBK in memory of the 25th anniversary of the Chernobyl accident // Your library: Zh. - 2011. - No. 10. - P. 48–55.
• Higginbotam A. Chernobyl: Disaster Story = Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster  (Russian) / transl. from English A. Bugaysky , scientific. ed. L. Sergeev . - M .: Alpina non-fiction , 2020 .-- 552 p. - ISBN 978-5-00139-269-9 .

Fiction

• Asmolov, V. G. Unfinished Tale  / V. G. Asmolov, E. A. Kozlova. - M. , 2018 .-- 336 s. - [Elena Aleksandrovna Kozlova - Ph.D., in 1965−1995, researcher, since 1986 - head of the laboratory of heat-insulating materials NIKIMT, participant in the liquidation of the Chernobyl accident, was awarded the Order of Courage in 2000, a member of the Union of Writers of Russia, laureate of the International prize named after M. A. Sholokhov]. - ISBN 978-5-88777-064-2 .
• Dyatlov, A. S. Chernobyl: How it was. - M  .: Nauchtekhlitizdat, 2003 .-- 191 p. - ISBN 5-93728-006-7 .
• Karpan NV . Chernobyl Revenge of the Peaceful Atom . K .: PE "CountryLife", 2005
• Medvedev, G.U. Nuclear tan: [Story]. - M  .: Book Chamber, 1990 .-- 413 p. - (Popular Library). - Content: Nuclear tan; Power unit; Chernobyl notebook; Green movement and nuclear energy: Experience in a constructive approach. - 100,000 copies.  - ISBN 5-7000-0223-X .
• Solovyov S. M., Kudryakov N. N., Subbotin D. V. Valery Legasov: Highlighted by Chernobyl: The history of the Chernobyl disaster in the notes of academician Legasov and in a modern interpretation. - M  .: Publishing house AST , 2020. - 320 p. - ISBN 978-5-17-118365-3 .
• Shcherbak, Yu. N. Chernobyl. - M  .: Soviet writer, 1991 .-- 464 p. - 100,000 copies.  - ISBN 5-265-01415-2 .

References

Event Description

• Asmolov, V. G. Boxes with vodka, biorobots and bare miners  : 11 inconsistencies in the series “Chernobyl” // Forbes . - 2019 .-- June 3.
• Dyatlov A. S. Chernobyl accident - memories on YouTube
• Chernobyl survivor - about the fateful experiment and the KGB interrogations on YouTube  - KishkiNa - 2018 (September 14) - [Interview, a description of the events of the senior Chernobyl unit control engineer, Boris Stolyarchuk, the last surviving experiment participant who was at the control room of the 4th Chernobyl power unit]

Official information

• International Chernobyl Science Information Network (ICRIN)
• IAEA of the Chernobyl accident  (Eng.)
  • International Atomic Energy Agency. Chernobyl accident: addition to INSAG-1 . Safety Publication Series No. 75-INSAG-7. IAEA, Vienna, 1993.
  • Chernobyl's Legacy: Summary Report. Report of the UN Chernobyl Forum.
• Zoriy P., Dederichs H., Pillath J., Heuel-Fabianek B., Hill P., Lennartz R. Long-Term Measurements of the Radiation Exposure of the Inhabitants of Radioactively Contaminated Regions of Belarus - The Korma Report II (1998— 2015) . Verlag Forschungszentrum Jülich, ISBN 978-3-95806-181-1 , 2016 The Korma Report II
• Accident at the Chernobyl nuclear power plant: 30 years later // World Health Organization
• Chernobyl // Institute for the Safe Development of Nuclear Energy RAS
• Accident at the Chernobyl nuclear power plant // Interdepartmental information system on the issues of ensuring radiation safety of the population and problems of overcoming the consequences of radiation accidents (EMERCOM of the Russian Federation)

Documents

• The technological regulations for the operation of 3 and 4 Chernobyl power units (valid at the time of the accident)
• Tables and graphs of changes in some parameters of the block before the accident
• Chernobyl tragedy in documents and materials  (Ukrainian) KGB archives
• Chernobyl: “There is a silver lining” (Mikhail Gorbachev) From the book “In the Politburo of the Central Committee of the CPSU ... According to the notes of Anatoly Chernyaev, Vadim Medvedev, Georgy Shakhnazarov (1985-1991)”
• Virtual exhibition of documents “Chernobyl disaster. 25 years later ” (inaccessible link) . Main Department of Justice of the Gomel Regional Executive Committee (March 17, 2011). Archived on August 18, 2011. (.) 

Alternative versions of the causes and consequences

• Analysis of the version: "earthquake - the cause of the accident." N. Carpan
• Chernobyl accident. Reasons, chronicle of events, conclusions. Boris Gorbachev
• Chernobyl disaster. Its causes are known. Victor Dmitriev
• The cause of the accident. Alexey Fatahov (VIUR)
• Greenpeace rejects Chernobyl toll
• Chernobyl and Corporations
• Geophysical aspects of the Chernobyl disaster. Vasiliev V.G. ( IAEA ), A. Fefelov ( RAEN ), I. Yanitsky ( VIMS ).

Community organizations and websites

• The myth of Chernobyl . Visit to the Chernobyl Zone  (inaccessible link)
• Chernobyl accident in the Open Directory Project link directory (dmoz)
• Chernobyl.info
• Site of disabled Chernobyl residents of St. Petersburg
• Chernobyl, as it were. The causes of the accident from the liquidator, a former employee of the Chernobyl nuclear power plant

Miscellaneous

• Newsreel and documentaries about the accident at the Chernobyl nuclear power plant // Net-Film News Archive
• Politburo extinguished the reactor with all the lies
• Black ... (true story). A. B. Kramer
• Borovoy A. Belarusian liquidator about fear, duty and deceit . Onliner.by (April 26, 2014). Archived on April 26, 2014. (.)

  Map of radioactive contamination with cesium-137 isotope  Google Maps   KMZ ( KMZ tag file for Google Earth )

• Valery Glazko “Chernobyl 20 years later”
• Alexander Kalugin “Today's understanding of the accident”
• Interview with Academician Spartak Belyaev: “Liquidation of the consequences of the Chernobyl disaster”
• Alexander Borovoi “Inside and outside the Sarcophagus”
• Rafael Harutyunyan “Chinese Syndrome”
• Alla Yaroshinskaya “Lies on the scales of Chernobyl”
• The bell of Chernobyl. 1987 documentary
• Chernobyl Nuclear Disaster - Surviving Disaster (BBC Documentary series) ( part 1 , part 2 , part 3 , part 4 , part 5 , part 6 )
• Land of Alienation. Chernobyl and its surroundings. 28 years after the accident
• Reznichenko A. Ya. Ten myths surrounding the accident at the Chernobyl nuclear power plant  // RIA Novosti . - April 24, 2009.
• Reznichenko A. Ya. Chernobyl: lies and truth after 30 years  // RIA Novosti . - 04/22/2016.