Chernobyl nuclear accident
Chernobyl nuclear accident (Encyclopedia of Environmental Issues, Revised Edition)
On April 26, 1986, nuclear power reactor number 4 exploded at the nuclear plant located about 15 kilometers (9 miles) from the small town of Chernobyl in the republic of Ukraine. As the core of the reactor began to melt, an explosion occurred that blew the top off the reactor and sent a wide trail of radioactive material across large parts of what was then the Soviet Union as well as much of Eastern and Western Europe. More than 116,000 people were evacuated within a 30-kilometer (19-mile) radius.
In addition to the political, social, and economic aftermath of the explosion, the consequences of human inability to prevent widespread damage were evident in the environment within five years of the Chernobyl disaster. A major release of radioactive materials into the atmosphere occurred during the first ten days following the explosion. Radioactive plumes reached many European countries within a few days, increasing radiation levels to between ten and one hundred times normal levels. Over time the contaminated lithosphere created a new biogeographical province characterized by irregular and complicated patterns of radioactivity in Belarus, Ukraine, and Russia, the countries most affected. In spite of some success in efforts to slow the flow of certain soluble radionuclides into the Black and Baltic seas, as well as into the Pripet, Dnieper, and Sozh rivers (all of which contribute water to the Kiev water reservoir), much contamination occurred...
(The entire section is 231 words.)
Contamination Effects (Encyclopedia of Environmental Issues, Revised Edition)
The effects of the radioactive contamination on vegetation have varied depending on the species. Damage to coniferous forests was more than ten times greater than that to oak forests and grass communities, and more than one hundred times greater than the damage to lichen communities. Ten years after the explosion, pine forests still had high levels of radionuclides in the uppermost layer of the forest floor, while birch forests had considerably lower levels. Large numbers of highly contaminated trees were felled, and restrictions were placed on cutting and using the wood in industry and for fuel. Likewise, the degrees of radiation damage and the doses absorbed varied among plant communities. In addition to killing or damaging plant life, the radiation disturbed the functioning of plant reproductive systems, resulting in sterility or decreases in both seed production and fertility. Other effects involved changes in plant chlorophyll, necessary for removing carbon dioxide from the air.
Among animals, lower life-forms have been found to have higher radiosensitivity levels; that is, mammals are less sensitive to radioactivity than are birds, reptiles, and insects. The severity of damage also depends on whether it is external or internal. The impact of environmental contamination may be less severe for animals than for plants because of the ability of animals to move from place to place and make selective contact with the...
(The entire section is 594 words.)
Further Reading (Encyclopedia of Environmental Issues, Revised Edition)
Alexievich, Svetlana. Voices from Chernobyl: The Oral History of a Nuclear Disaster. Translated by Keith Gessen. New York: Picador, 2006.
Bailey, C. C. The Aftermath of Chernobyl. Dubuque, Iowa: Kendall Hunt, 1993.
Marples, David R. Chernobyl and Nuclear Power in the USSR. New York: St. Martin’s Press, 1986.
_______. The Social Impact of the Chernobyl Disaster. New York: St. Martin’s Press, 1988.
Medvedev, Zhores A. The Legacy of Chernobyl. New York: W. W. Norton, 1990.
Savchenko, V. K. The Ecology of the Chernobyl Catastrophe. New York: Informa Healthcare, 1995.
Yaroshinskaya, Alla. Chernobyl: The Forbidden Truth. Lincoln, Nebr.: Bison Books, 1995.
(The entire section is 94 words.)
Chernobyl nuclear accident
Definition (Encyclopedia of Global Resources)
On April 26, 1986, an accident at the Chernobyl nuclear plant in Ukraine dispersed radioactive material over much of Europe, killing several hundred people at or near the reactor and contaminating crops and animals as far away as northern Scandinavia.
(The entire section is 38 words.)
Overview (Encyclopedia of Global Resources)
Nuclear reactors produce electricity using steam produced from the heat given off in nuclear decay to turn turbines that generate electricity. In late April of 1986, operators at reactor number four of the Chernobyl nuclear plant undertook a test to determine how long the plant’s turbines could produce electric power and operate the plant’s safety systems after the steam was shut off. The operators made a series of errors that allowed the cooling water to drop below the critical level. Since the emergency cooling system had previously been shut down, it did not respond to the low water level, and the temperature of the core increased. At 1:23 a.m. on April 26, the remaining water in the reactor core—where the uranium fuel decays, generating heat—expanded rapidly, producing steam. The resulting explosion destroyed the core and part of the building. A fireball appeared, and burning lumps of graphite and reactor fuel were dispersed around the site, starting fires that carried more radioactive material into the air.
Radiation poisoning resulted in the hospitalization of approximately two hundred plant workers and firefighters within thirty-six hours of the explosion. Everyone within 10 kilometers of the plant, except for crews still trying to contain the radiation release, was evacuated by the evening of April 26. On May 2 this evacuation zone was expanded to 30 kilometers. More than 100,000 people were eventually moved from the...
(The entire section is 467 words.)