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Chernobyl nuclear accident, Soviet Union

Abandoned City or Prypiat,
Chernobyl nuclear accident

Chernobyl control room.
Before the nuclear accident

Current status of the control room.
Chernobyl nuclear accident

Consequences Of The Chernobyl Nuclear Accident

Consequences of the Chernobyl nuclear accident

The Chernobyl nuclear accident led to a subsequent fire. This fire increased the dispersal effects of the radioactive products, and the thermal energy accumulated by the graphite gave the fire itself and atmospheric dispersion even greater magnitude. Due to the explosion of the reactor and the subsequent fire, a series of consequences were unleashed in many aspects. In this section we discuss the health, environmental, technical and political consequences related to the Chernobyl nuclear disaster.

Of the radioactive products released, iodine-131 (with a half-life of 8.04 days) and cesium-137 (with a half-life of about 30 years), of which approximately half, were released, were particularly dangerous. of the amount contained in the nuclear reactor. Furthermore, it was estimated that all the xenon gas was expelled outside the atomic reactor. These products were unevenly deposited, depending on their volatility and the rains during those days.

The heaviest were found within a radius of 110 km, and the most volatile reached great distances. Thus, in addition to the immediate impact in Ukraine and Belarus, radioactive contamination reached areas in the European part of the former Soviet Union, and in the United States and Japan.

During the seven months following the atomic accident, the remains of the damaged nuclear reactor 4 were buried by the liquidators, through the construction of a “sarcophagus” of 300,000 tons of concrete and metallic lead structures to prevent the dispersion of the fission products. nuclear. In principle, this sarcophagus was an interim solution and should be under strict control due to its long-term instability, as it could lead to collapse.

What were the health consequences of the Chernobyl nuclear accident?

International Program on the Health Effects of the Chernobyl Accident

To determine the effects of radiation on people's health, the World Health Organization developed the IPHECA (International Program on the Health Effects of the Chernobyl Accident), so that the possible health consequences of the accident could be investigated. These consequences included effects related to the anxiety produced in the inhabitants of the most polluted areas as a result of the evacuation of their homes, and the fear of possible future damage to health due to the biological effects of radiation. In addition, the program provided technical assistance to the Belarus national health system, the Russian Federation and Ukraine to alleviate the health consequences of the Chernobyl accident.

The results obtained with the IPHECA pilot projects have considerably improved the scientific knowledge of the effects of a radioactive accident on human health, so that they can lay the foundations for planning guidelines and the development of future research.

Immediate health consequences

Consequences of the Chernobyl nuclear accidentThe immediate consequences of the accident on the health of people affected by the Chernobyl nuclear accident were as follows:

237 people showed symptoms of Acute Irradiation Syndrome (SIA), confirming the diagnosis in 134 cases. 31 people died during the accident, of which 28 (firefighters and operators) were victims of the high dose of radioactivity, and 3 from other causes. After this acute phase, 14 more people have died in the ten years after the accident.

Between 600,000 and 800,000 people (specialized workers, volunteers, firefighters, military and others) called liquidators, in charge of control and cleaning tasks, who died in different periods.

16,000 inhabitants of the area were evacuated several days after the accident, as a protection measure against high levels of radioactivity, establishing an exclusion zone in the most contaminated territories, within a radius of 30 km around the facility.

565 cases of thyroid cancer in children mainly (aged between 0 and 14 years) and in some adults, who lived in the most contaminated areas (208 in Ukraine, 333 in Belarus and 24 in the Russian Federation), of which , 10 cases have been fatal due to radiation.

Consequences of the Chernobyl nuclear accidentOther cancers, particularly leukemia, have not registered statistically significant deviations from the expected incidence under normal conditions.

Psychosocial effects caused by causes not related to radiation, due to lack of information, evacuation of those affected and fear of the long-term biological effects of radiation. These effects were a consequence of the surprise reaction of the national authorities to the Chernobyl nuclear accident, regarding the extent, duration and contamination over long distances. As the emergency procedures were non-existent, there was little information available, noting distrust and public pressure for measures to be taken, but official decisions did not take into account the psychological effects of the population, Misinterpretations of the International Commission On Radiological Protection (ICRP) recommendations for food intervention levels are being carried out. All this was translated into a significant number of health disorders, such as anxiety, depression and various psychosomatic effects.

The World Health Organization (WHO) purchased medical equipment and supplies for the 3 countries (Belarus, the Russian Federation, and Ukraine) worth about $ 16 million. The rest of the expenses of the pilot projects were dedicated to aid to the programs, scientific meetings, training courses in foreign research institutions and clinical institutions for 200 specialists, and to provide capital to continue with the activities of the IPHECA program. 

    Radiation dose ranges received

    According to the OECD's Atomic Energy Agency (NEA), the radiation dose ranges received by the different groups were as follows:

    • Liquidators: of the total of the liquidators, about 200,000 received variable doses from 15 to 170 millisievert (mSv).
    • Evacuated: the 116,000 people evacuated, most of the plant's radius of action of 30 km, received high doses (10% more than 50 mSv and 5% more than 100 mSv), especially in the thyroid by incorporation of iodine-131. The most evacuated area was Prypiat, a mere 2 km from the Chernobyl nuclear power plant, becoming a "ghost town" as the 60,000 people who lived there left the city.
    • Inhabitants of contaminated areas: About 270,000 people continued to live in contaminated areas, so children received high doses of thyroid due to ingestion of milk contaminated with iodine-131 during the first weeks after the accident. After food control, during the period 1986-1989, the dose range of cesium-137 in the soil was from 5 to 250 mSv / year, with an average of 40 mSv / year.
    • Rest of the population: Volatile radioactive materials spread throughout the northern hemisphere, although the doses received by the population were very low and of little importance from the point of view of radiation protection. Radiation doses during the first year ranged in Europe between 0.005 and 0.5 mSv, in Asia between 0.005 and 0.1 mSv, and in North America they were of the order of 0.001 mSv.

    Other health studies

    Consequences of the Chernobyl nuclear accidentAnother study obtained different results regarding Chernobyl. According to this, half a million people have died and the data provided by Ukraine is not complete. This would be the number of people (500,000) who would have lost their lives, due to the radioactive cloud, which contaminated much of Europe. And another 30,000 would die in the coming years. These evaluations present an important difference with the WHO and IAEA research.

    According to Greenpeace, in total, 30% of the areas where nine million people live have been contaminated with cesium -137. According to a technician from the Ukrainian government science center, cases of thyroid cancer, leukemias and genetic mutations are registered in Ukraine that did not appear in the WHO statistics, and which were practically unknown twenty years ago.

    What were the environmental consequences of the Chernobyl nuclear disaster?

    Consequences of the Chernobyl nuclear accidentNuclear reactor 1 at the Chernobyl nuclear power plant had about one hundred and ninety tons of nuclear fuel at the time of the accident. Some estimates calculate that around 3.5% of it was emitted into the atmosphere, but these data are not at all certain, since different estimates place the amount of fuel emitted in extraordinarily disparate figures, ranging between 5% and 97%. .

    The radioactive nuclides of cesium -137 (which emits beta radioactivity), iodine -131 (beta decay) and tellurium -132 (beta decay) and to a lesser degree strontium -90 (beta decay) and plutonium-141 (alpha radioactivity) among others once released into the air, they no longer spread homogeneously, in concentric concentrations centered in the plant. These radioactive nuclides move with the air masses according to the meteorology of the moment, and especially linked to the small solid particles (aerosols) of these air masses, originating from the smoke of the fire, atmospheric pollution present in nature. These can be stopped and accumulated in encountering obstacles, such as a tree (which stops the radioactive particle, preventing it from moving, and the alpha and beta radiation it emits,

    Radioactive contamination spread to Asian and especially European continents in waves of air bags generally more concentrated at the beginning of their trajectory and more widespread. These airbags also covered larger areas as they progressed. Six waves stood out, in the form of irregular petals emerging from Chernobyl.

    Studying the causes of the accident made new designs for reactors and nuclear power plants around the world different. The following studies took into account other possible malfunctions and accidents, and imagining and imposing the appropriate means to avoid them, as well as active and passive safety measures that, in the unlikely event that there were any of these incidents, minimizing the effects and radiation does not pass outside.

    Existing nuclear power plants that did not meet these new criteria were closed or adapted. In January 1993, the IAEA revised the analysis on the causes of the accident, attributing an error in the design of the atomic reactor.

    Throughout Europe, a network of atmospheric radioactivity detection and control devices spread throughout its territory was created, which allows observing and taking the necessary measures in the event of accidents, leaks or any type of accident involving ionizing radiation in the atmosphere. They also make it possible to measure radioactivity, which is also used to study modeling of the behavior of air masses.

    At the environmental and health level there were major changes related to dose values ​​(of radiation and also of other pollutants) that from then on the standards would consider as admissible. Regulatory criteria regarding pollution in general were added, such as dust (particles), which now it is known that, if they do not have such immediate effects as ionizing radiation on the body, they do have, and important, long-term effects .

    The criteria of the so-called "weak dose" were also modified, criteria still in debate because it is known, every day with more certainty, that any small dose of, for example, lead, Causes an equal or even greater effect with the passage of years that the highest doses. For example, in 2011 the WHO does not consider any of the three million children in the territories officially contaminated by the Chernobyl nuclear accident healthy. According to this organization, all develop different pathologies, of various degrees of severity, related to the weakening of the defenses.

    Environmentally since the nuclear accident it is considered that it is known with certainty, and necessary technical and legal measures are taken, that it is not possible to decontaminate an entire territory after certain types of incidents, that is to say that it can never be like before it but on the contrary , the negative ecological consequences (genetic mutations, cancer cases, transmission of these to subsequent generations, etc.) increase.

    Political consequences after the Chernobyl nuclear accident

    The Chernobyl accident was decisive for the beginning of the process of opening the Soviet Union in Western Europe, for the end of the cold war and perestroika.

    In Italy, for example, the Chernobyl accident and the fact that radioactivity affected the country led to the proposal of a referendum in which it was asked whether or not one wanted to have nuclear energy from nuclear plants located in Italy. The referendum was held on November 8, 1987 and 80% of the voters answered "no", which led to the closure of the three plants that were currently operating in Italy.

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    Published: December 5, 2019
    Last review: December 5, 2019