The April 1986 disaster at the Chernobyl nuclear power plant in Ukraine was the product of a flawed Soviet reactor design coupled with serious mistakes made by the plant operators. It was a direct consequence of Cold War isolation and the resulting lack of any safety culture.

The Chernobyl disaster began at 1.23 a.m. on Saturday 26 April 1986, in a civilian nuclear power station of Kiev Oblast (province) in the (then) Ukrainian SSR (Soviet Socialist Republic). A chemical explosion at the station’s fourth reactor and an uncontrolled graphite fire that followed led to the release of more than 450 radionuclides, comprising about 3.5 percent of the fuel stored in the reactor core. Official reports put the immediate death toll at 31, but it is widely believed that many more died in the first hours and weeks after the explosion. The Ukrainian government has estimated the number of deaths among clean-up workers alone as 7,000-8,000. Total civilian casualties are not known and may never be known. Although nuclear radiation is no longer leaking from the damaged reactor into the atmosphere, this event is far from over. Its repercussions will continue well into the next century, sometimes in places far distant from the point of origin. There are those who believe that this was a unique occurrence in the history of civilian nuclear power. However, it is difficult to judge such a claim because the context in which it occurred was highly unusual. The disaster took place in a country on the brink of social upheaval, with a political administration that was to undertake major reforms under a new leader. These factors strongly affected the way the event was reported and the subsequent responses.

Chernobyl Power Complex, lying about 130 km north of Kiev, Ukraine, and about 20 km south of the border with Belarus, consisted of four nuclear reactors of the RBMK-1000 design (see information page on RBMK Reactors). Units 1 and 2 were constructed between 1970 and 1977, while units 3 and 4 of the same design were completed in 1983. Two more RBMK reactors were under construction at the site at the time of the accident. To the southeast of the plant, an artificial lake of some 22 square kilometres, situated beside the river Pripyat, a tributary of the Dniepr, was constructed to provide cooling water for the reactors.This area of Ukraine is described as Belarussian-type woodland with a low population density. About 3 km away from the reactor, in the new city, Pripyat, there were 49,000 inhabitants. The old town of Chornobyl, which had a population of 12,500, is about 15 km to the southeast of the complex. Within a 30 km radius of the power plant, the total population was between 115,000 and 135,000 at the time of the accident.


Long-term health effects of the Chernobyl accident

In 1989, the World Health Organization (WHO) first raised concerns that local medical scientists had incorrectly attributed various biological and health effects to radiation exposure. The Government of the USSR requested the International Atomic Energy Agency (IAEA) to coordinate an international experts’ assessment of accident’s radiological, environmental, and health consequences in selected towns of the most heavily contaminated areas in Belarus, Russia, and Ukraine.

Between March 1990 and June 1991, a total of 50 field missions were conducted by 200 experts from 25 countries (including the USSR), 7 organisations, and 11 laboratories. In the absence of pre-1986 data, it compared a control population with those exposed to radiation. Significant health disorders were evident in both control and exposed groups, but, at that stage, none was radiation-related. People in the area have suffered a paralysing fatalism due to myths and misperceptions about the threat of radiation, which has contributed to a culture of chronic dependency. Some “took on the role of invalids.” Mental health coupled with smoking and alcohol abuse is a very much greater problem than radiation, but worst of all at the time was the underlying level of health and nutrition. Apart from the initial 116,000, relocations of people were very traumatic and did little to reduce radiation exposure, which was low anyway. Psycho-social effects among those affected by the accident are similar to those arising from other major disasters such as earthquakes, floods, and fires.


Some facts of the Chernobyl disaster

1. The Chernobyl accident in 1986 was the result of a flawed reactor design that was operated with inadequately trained personnel.

2. The resulting steam explosion and fires released at least 5% of the radioactive reactor core into the environment, with the deposition of radioactive materials in many parts of Europe.

3. Two Chernobyl plant workers died due to the explosion on the night of the accident, and a further 28 people died within a few weeks as a result of acute radiation syndrome.

4. The United Nations Scientific Committee on the Effects of Atomic Radiation has concluded that, apart from some 6500 thyroid cancers (resulting in 15 fatalities), “there is no evidence of a major public health impact attributable to radiation exposure 20 years after the accident.”

5. Some 350,000 people were evacuated as a result of the accident, but the resettlement of areas from which people were relocated is ongoing.


Chernobyl disaster today

Today, the exclusion zone is eerily quiet, yet full of life. Though many trees have regrown, scientists have found evidence of elevated levels of cataracts and albinism, and lower rates of beneficial bacteria, among some wildlife species in the area in recent years. Yet, due to the exclusion of human activity around the shuttered power plant, the numbers of some wildlife, from lynxes to elk, have increased. In 2015, scientists estimated there were seven times more wolves in the exclusion zone than in nearby comparable reserves, thanks to humans’ absence.

The economic and political toll hastened the end of the USSR and fueled a global anti-nuclear movement. The disaster has been estimated to cost some $235 billion in damages. What is now Belarus, which saw 23 percent of its territory contaminated by the accident, lost about a fifth of its agricultural land? At the height of disaster response efforts, in 1991, Belarus spent 22 percent of its total budget dealing with Chernobyl. Today, Chernobyl beckons to tourists who are intrigued by its history and its danger. But though Chernobyl symbolizes the potential devastation of nuclear power, Russia never quite moved beyond its legacy—or its technology. As of 2019, there are still 11 operational RBMK reactors in Russia.