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Chernobyl disaster, 25 years on

On April 26, 1986, the world’s worst nuclear power plant accident occurred at the Chernobyl nuclear power station. Now, 25 years later, the current crisis in Fukushima is being called the “worst since Chernobyl.” Will we avoid another disaster? And further more, in another 25 years, how will we feel about nuclear energy?

Below a comprehensive article on Chernobyl by Philip R. Pryde, as it appears in The Oxford Companion to Global Change (Ed. David Cuff & Andrew Goudie). For further reading, I suggest looking to the newly published volume Nuclear Energy: What Everyone Needs to Know.

The most catastrophic accident ever to occur at a commercial nuclear power plant took place on April 26 , 1986, in northern Ukraine at Chernobyl (Chornobyl’ in Ukrainian). Intense radioactive fallout covered significant portions of several provinces in Ukraine, Belarus, and the Russian Federation, and lesser amounts fell out with precipitation in numerous other European countries. The resultant health and environmental consequences are ongoing, widespread, and serious.

The Chernobyl power station is one of several such complexes built in Ukraine. At the time, it was believed that nuclear energy would entail negligible damage to the environment. Four other large nuclear power complexes have been constructed and Ukraine has a major uranium-mining complex and numerous research facilities.

The Chernobyl reactors utilize a graphite-moderated type of nuclear reactor (Russian acronym, RBMK), with a normal output of 1,000 megawatts. These units are water-cooled and employ graphite rods to control core temperatures. Each reactor houses 1,661 fuel rods that contain mainly uranium-238 plus much smaller amounts of enriched uranium-235. There are several dangers inherent in the design of RBMK-1000 reactors, including the ability of the operators to disengage safety controls, the lack of a containment dome, and the possibility that, at very low power levels, a rapid and uncontrollable increase in heat can occur in the reactor’s core and may result in a catastrophic explosion ( Haynes and Bojcun , 1988 , pp. 2–4).

This was what happened early in the morning of April 26 , 1986. A series of violations of normal safety procedures, committed during a low-power experiment being run on reactor number 4, resulted in a thermal explosion and fire that destroyed the reactor building, exposed the core, and vented vast amounts of radioactive material into the atmosphere. Pieces of the power plant itself were found up to several kilometers from the site of the explosion.

This radiation continued to be released into the atmosphere over a period of nine days, with the prevailing winds carrying the radioactive material initially in a northwesterly direction over northern Europe. The winds later shifted to the northeast, carrying fallout southwestward into central Europe and the Balkan peninsula. The overall result was significant radioactive fallout (mainly associated with rainfall) in Austria, Czechoslovakia, Finland, Germany (mainly Bavaria), the United Kingdom, Hungary, Italy, Poland, Romania, Sweden, and Switzerland. Lower levels of radioactive deposition were reported in Denmark, France, the Benelux countries, Greece, Ireland, Norway, Yugoslavia, and several other European nations (Medvedev 1990 , chap. 6). The republics of Estonia, Latvia, and Lithuania were also directly in the path of the initial plume.

In the Soviet Union, the regions that received the highest levels of radioactive contamination were in the northern Kiev and eastern Zhytomyr provinces in Ukraine, and in the Homyel’ and Mahilyow provinces of Belarus (then Belorussia). In the Russian Federation, areas situated closest to the Belarus border, such as western Bryansk province, experienced the greatest radiation problems (NEA, 1995 , p. 32). Lighter fallout, measured in terms of long-lived cesium-137, was recorded in parts of other Ukrainian provinces, as well as in the Baltic republics. Among the capital cities of these provinces, only Homyel’ was in a region of high fallout, but other large cities, such as Orel, Mogilev, and Kiev, were right on the border of the danger zone ( Bradley , 1997 , p. 368; Marples, 2004 , p. 598).

Large-scale evacuations were conducted in the most heavily affected sections of these provinces. The number of people who had to be resettled totaled around 107,000 in Belarus alone, plus approximately fifty thousand more in both Russia and Ukraine (International Atomic Energy Agency, 1996 , p. 7). Another source cites a figure of over 84,000 people as having been relocated in the Russian Republic ( Savchenko , 1995 , p. 76), and other sources speak of over 100,000 evacuees in Ukraine. In many instances the displaced populations had to be moved quickly to places with inadequate housing, social services, and employment. For unknown reasons, thousands of people were not relocated from areas of high radiation until many years after the accident.

The effects on human health have been enormous. Around 600,000 people have been “significantly exposed” to radiation from the Chernobyl accident, and thousands of people have developed radiation sickness from exposure to contamination produced by the explosion and subsequent fire ( Medvedev , 1990 , pp. 129–130). Approximately 270,000 people still live in areas sufficiently contaminated to require ongoing protection measures (NEA, 1995 , p. 12). Russia, like the former Soviet Union, still reports an official figure of around thirty-one deaths, but the actual number of Chernobyl-related fatalities is often suggested to be in the hundreds, if not the thousands ( Marples , 1993 , p. 282). In 1996 , a senior Russian environmental official stated that “official [Chernobyl] statistics are incomplete and irreversibly falsified” ( Yablokov , 1993 ).

Medical problems among the general population that are probably attributable to Chernobyl are a serious concern. The first wave of victims were workers at the plant, and the thousands of containment and cleanup personnel who needed treatment for radiation sickness. The workers’ town of Pripyat’ was not immediately evacuated nor the people even informed of the radiation danger, thereby placing many people, especially schoolchildren, at risk. The 30-kilometer-radius “exclusion zone” around the plant was not declared until May 3 and was inadequate in size. There is general agreement that there will be grave long-term cancer mortality from the accident but also vast disagreement over the magnitude of these carcinogenic consequences. The optimists suggest only a few hundred “excess deaths,” all in the former Soviet republics, whereas the pessimists predict as many as 280,000 fatalities worldwide ( Medvedev , 1990 , p. 166).

The southeastern portion of Belarus received the plurality of fallout from Chernobyl; indeed, between half and two-thirds of all the radioactive fallout from Chernobyl fell on Belarusian territory. The environmental and human toll in this area has been at least as great as that experienced in Ukraine. The city of Homyel’, with a population of around half a million, recorded the highest increase in background radiation of any major city in the Soviet Union. Many smaller towns in Belarus, especially those directly across the Pripyat’ River from Chernobyl, received more. Approximately 20% of the country’s agricultural land, possibly totaling in excess of a quarter million hectares, as well as 15% of the forests of Belarus, are no longer usable ( Savchenko , 1995 ).

Perhaps the most tragic consequence of the accident has been the sharp increase in the incidence of thyroid cancer in children since 1989 in Ukraine, Belarus, and Russia. In Minsk (city and province) in 1986 there had been no such cancers, but by 1992 twenty-one cases had been recorded; in Homyel’ province there had been one in 1986 but 97 more from 1987 to 1992 . For all of Belarus, there had been two cases of thyroid cancer in children in 1986 , but 172 cases were recorded in the period 1986 – 1992 ( Marples , 1993 , pp. 285–290; World Health Organization, 1995 , pp. 20–24). By 1994 , the total exceeded three hundred (NEA, 1995 , p. 63). Since the breakup of the Soviet Union, little assistance in dealing with the consequences of Chernobyl has come from Moscow. Currently, a significant percentage of the national budget of Belarus must be devoted to dealing with the relocation, environmental, and public health costs of the accident.

The environmental consequences of the accident include large areas of contaminated soil, forests, and water. Soil and water pollution from the accident have been recorded in twenty-two provinces of the former Soviet Union, as well as in several foreign countries. In places, radionuclides have been measured in the soil at depths up to 25 centimeters, which is the vertical zone in which crop cultivation takes place. Because of radioactive contamination of soil, large areas of fertile farmland have had to be taken out of production. In northern Ukraine, over 100,000 hectares of agricultural land, which contain some of the world’s richest soils, have had to be abandoned ( Savchenko , 1995 , p. 53). Meat and dairy products had to be destroyed, and deformed calves and pigs were born on nearby collective farms. The farmers have had to find work elsewhere, and lost agricultural output made up by increased production in other regions. The Nuclear Energy Agency (NEA, 1995 , p. 81) has warned that forest products from the contaminated regions may present long-term radiation exposure problems.

Water supplies were not only contaminated by the immediate fallout, but also by the transport of radioactive sediments. Fishing was prohibited in the portions of the Pripyat’ River and the Kiev Reservoir near the accident site, and outside sources of water for Kiev had to be developed quickly. The Pripyat’ River flows through the power plant complex (and was the source of its cooling water), and thence flows into the Dnieper River, which runs through Kiev. Several million people living between Kiev and the Black Sea depend upon water from the Dnieper, and thus are potentially exposed to radiation moving through it. In the mid-1990s, though, contamination of drinking water was believed not to be a problem (NEA, 1995 , p. 81). However, significant amounts of strontium-90 may be imbedded in the banks of the Pripyat’ River. Bank collapse and shoreline erosion could eventually release this radiation.

A large concrete containment facility, termed a sarcophagus, was completed around the damaged Unit Number 4 in November 1986 , finally halting the release of radiation. However, it was never viewed as a permanent containment structure, and because of the haste of its construction, serious doubts exist about its long-term viability. The sarcophagus covers hundreds of metric tons of nuclear fuel, which continue to produce high temperatures and radiation levels within the ruined reactor building. But the current structural stability of the sarcophagus is very questionable, and it will have to be replaced. The huge cost of this exceeds Ukraine’s resources. As a result, at the 1997 economic summit meeting, the major world powers pledged U.S.$300 million to assist in the construction of a second concrete containment facility.

The health and environmental consequences of the accident have been sufficiently great that there was a widespread call to shut down the Chernobyl complex completely, and this was done in 2000 . The Ukrainian government has linked the complete closure of the site to the receipt of foreign funding for cleanup assistance that was promised by multinational agreement in 1995 .

The consequences of the Chernobyl disaster, including delayed health effects, will remain as significant problems for decades to come ( Poyarkov , 2000 ). The huge costs of cleaning up the contaminated land and structures, caring for the displaced multitudes, and rebuilding the sarcophagus will have to be funded somehow, and may exceed the ability of Belarus and Ukraine to handle the costs ( Pryde , 1995 , chap. 10). In terms of future energy supplies, the accident has had a depressive effect on nuclear power in many parts of the world, most notably the United States, where no new development of nuclear power has taken place since 1986 . Russia, on the other hand, plans to continue with its nuclear program and has announced plans to build a number of new units early in the twenty-first century. The ramifications of the Chernobyl accident are extensive and continuing, and it is likely that it will be remembered as one of the defining events of the twentieth century.


Bradley, D.J. Behind the Nuclear Curtain: Radioactive Waste Management in the Former Soviet Union. Columbus, Ohio: Battelle Press, 1997 , pp.pp. 345–370. The most comprehensive work to date on all aspects of commercial and military radioactive wastes in the former Soviet republics.

Haynes, V., and M. Bojcun . The Chernobyl Disaster. London: Hogarth Press, 1988 . An early review of the disaster and its immediate effects.

International Atomic Energy Agency. One Decade after Chernobyl: Summing up the Consequences of the Accident. Vienna: IAEA, 1996 . Summary report of the Joint EC/IAEA/WHO international conference, “One Decade After Chernobyl,” held in Vienna, 8 – 12 April 1996 .

Marples, D.R. “A Correlation between Radiation and Health Problems in Belarus?” Post-Soviet Geography 34 ( 1993 ), pp.281–292.

Marples, D.R. “Chernobyl: A Reassessment” . Eurasian Geography and Economics 45 ( 2004 ), pp.588–607.

Medvedev, Z. The Legacy of Chernobyl. Oxford: Blackwell, 1990 . A critical evaluation of Chernobyl and its aftermath by a Russian dissident.

NEA. Chernobyl: Ten Years on Radiological and Health Impact. Paris: Nuclear Energy Agency, 1995 . A detailed study of the health and environmental consequences of Chernobyl.

Poyarkov, V., et al. The Chornobyl Accident: A Comprehensive Risk Assessment. Columbus, Ohio: Batelle Press, 2000 .

Pryde, P.R., ed. Environmental Resources and Constraints in the Former Soviet Republics. Boulder, Colo.: Westview Press, 1995 . Chapters 9, 10, and 11 are on environmental management problems in Ukraine and Belarus.

Savchenko, V.K. The Ecology of the Chernobyl Catastrophe. Paris, Casterton Hall, U.K., and New York: UNESCO and Parthenon Publishing, 1995 .

World Health Organization. Health Consequences of the Chernobyl Accident. Geneva: WHO, 1995 . This is the most recent United Nations report on this subject.

Yablokov, A.V., et al. “Facts and Problems Related to Radioactive Waste Disposal in Seas Adjacent to the Territory of the Russian Federation.” Report to the President of the Russian Federation by the Government Commission on Matters Related to Radioactive Waste Disposal at Sea, 24 October 1992 . Moscow, 1993 . Yablokov was senior adviser on environmental matters to President Yeltsin.

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