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 resulted in a subsequent fire. This fire increased the dispersal effects of radioactive products, and the thermal energy accumulated by graphite still gave greater magnitude to the fire itself and atmospheric dispersion. Due to the explosion of the reactor and the subsequent fire, a series of consequences were triggered in many aspects. In this section we analyze the consequences related to health, the environment, technical and political consequences related to the Chernobyl nuclear disaster.

Of the radioactive products released were especially dangerous iodine-131 (whose half-life is 8.04 days) and cesium-137 (with a half-life of about 30 years), of which approximately half came out of the amount contained in the nuclear reactor. In addition, it was estimated that all xenon gas was expelled outside the atomic reactor. These products were deposited unevenly, depending on their volatility and rainfall 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 on Ukraine and Belarus, radioactive contamination reached areas of the European part of the former Soviet Union, and the United States and Japan.

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

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 of the fear of possible future health damage due to the biological effects of radiation. In addition, the program provided technical assistance to the national health system of Belarus, 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 the foundations of the planning guides and the development of future research can be laid.

Immediate health consequences

Food Pollution in ChernobylThe immediate consequences of the accident on the health of people affected by the Chernobyl nuclear accident were the following:

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 within ten years after the accident.

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

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

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

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

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

The World Health Organization (WHO) bought medical equipment and supplies for the 3 countries (Belarus, Russian Federation and Ukraine) worth about 16 million dollars. The rest of the expenses of the pilot projects was dedicated to aid for programs, scientific meetings, training courses in foreign research institutions and in 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 Atomic Energy Agency (NEA), the radiation dose ranges, received by the different groups, were as follows:

  • Liquidators: of the total liquidators, some 200,000 received varying doses from 15 to 170 millisievert (mSv).
  • Evacuated: the 116,000 people evacuated, most of a radius of action of the central 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 scarce 2 km from the Chernobyl nuclear power plant, becoming a “ghost town” when the 60,000 people who lived there left the city.
  • Inhabitants of contaminated areas: around 270,000 people continued to live in contaminated areas, so that 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 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 unimportant from the point of view of radiation protection. The 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 studies on health

Liquidators of the Chernobyl nuclear accidentAnother study obtains different results compared to 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 polluted 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 in which nine million people live have been contaminated with cesium -137. According to a technician from the scientific center of the Ukrainian government, cases of thyroid cancer, leukemia and genetic mutations that are not listed in the WHO statistics are registered in Ukraine and were virtually unknown twenty years ago.

Environmental consequences of the Chernobyl nuclear accident

Liquidators of the Chernobyl nuclear accidentThe nuclear reactor 1 of 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 safe, and 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 radioactivity beta), iodine -131 (beta decay) and tellurium -132 (beta decay) and to a lesser extent strontium -90 (beta decay) and plutonium-141 (alpha radioactivity) among others , once released into the air, they do not extend more evenly, in concentric concentrations centered on the plant. These radioactive nuclides move with the air masses according to the weather of the moment, and especially linked to the small solid particles (aerosols) of these air masses, coming from the fumes 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 radiations it emits,

Radioactive contamination spread to the Asian and especially European continents in waves of airbags in general more concentrated at the beginning of its trajectory and more widespread. These airbags also covered larger areas, as they progressed. Six waves stood out, shaped like irregular petals coming out of Chernobyl.

The study of the causes of the accident made the new designs of 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 and also active and passive safety measures that, in the unlikely event that there were any of these incidents, minimize the effects and that The 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 reviewed the analysis of 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 was distributed throughout its territory that allows observing and taking the necessary measures in cases of accidents, leaks or any type of accident involving ionizing radiation in the atmosphere. They also allow measuring radioactivity, which is also used to study the 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 thereafter the standards would consider as admissible. Normative criteria were added regarding pollution in general, such as dust (particles), which is now known that, if they do not have such immediate effects as ionizing radiation in the body, they do have, and important, long-term .

The criteria of the considered "weak doses" were also modified, criteria still under debate because it is known, every day with more certainty, that every small dose of, for example, lead, Causes an effect equal or even higher with the passage of the years that the highest doses. For example, in 2011 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, everyone develops different pathologies, of varying degrees of severity, related to the weakening of 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 a certain type of incident, that is, it can never be as before it but on the contrary , the negative ecological consequences (genetic mutations, cases of cancer, transmission of these to later generations, etc.) increase.

Political consequences after the Chernobyl atomic accident

The Chernobyl accident was decisive for the start of the opening process of 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 the radioactivity affected the country caused the proposal of a referendum in which it was asked whether or not nuclear power from nuclear power plants located in Italy was wanted. 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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Last review: December 5, 2019