Ing. materiales

he Chernobyl disaster was a nuclear accident of catastrophic proportions that occurred on 26 April 1986, at the Chernobyl Nuclear Power Plant in Ukraine (then in the Ukrainian Soviet Socialist Republic, part of the Soviet Union). It is considered the worst nuclear power plant accident in history and is the only level 7 event on the International Nuclear Event Scale.
The disaster occurred at01:23, at reactor number four at the Chernobyl plant, near the town of Pripyat, during an unauthorized systems test. A sudden power output surge took place, and when an attempt was made at an emergency shutdown, a more extreme spike in power output occurred which led to the rupture of a reactor vessel as well as a series of explosions. This event exposed the graphite moderator components of thereactor to air and they ignited; the resulting fire sent a plume of radioactive fallout into the atmosphere and over an extensive area, including Pripyat. The plume drifted over large parts of the western Soviet Union, and also much of Europe. As of December 2000, 350,400 people had been evacuated and resettled from the most severely contaminated areas of Belarus, Russia, and Ukraine.[1][2]According toofficial post-Soviet data, up to 70% of the fallout landed in Belarus.[3]
Following the accident, Ukraine continued to operate the remaining reactors at Chernobyl for many years. The last reactor at the site was closed down in 2000.[4]
The accident raised concerns about the safety of the Soviet nuclear power industry as well as nuclear power in general, slowing its expansion for a number ofyears while forcing the Soviet government to become less secretive about its procedures.[5]
Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl accident. Fifty deaths, all among the reactor staff and emergency workers, are directly attributed to the accident. It is estimated that there may ultimately be a total of4,000 deaths attributable to the accident, due to increased cancer risk.[6]
Contents [hide] * 1 Accident * 1.1 Conditions prior to the accident * 1.2 Experiment and explosion * 1.2.1 Radiation levels * 1.2.2 Plant layout * 1.2.3 Individual involvement * 1.2.4 Deaths and survivors * 1.3 Immediate crisis management * 1.3.1 Radiation levels* 1.3.2 Fire containment * 1.3.2.1 Timeline * 1.3.3 Evacuation of Pripyat * 1.3.4 Steam explosion risk * 1.3.5 Debris removal * 2 Causes * 3 Effects * 3.1 International spread of radioactivity * 3.2 Radioactive release * 3.3 Health of plant workers and local people * 3.4 Residual radioactivity in the environment *3.4.1 Rivers, lakes and reservoirs * 3.4.2 Groundwater * 3.4.3 Flora and fauna * 4 Chernobyl after the disaster * 5 Recovery process * 5.1 Recovery projects * 5.1.1 The Chernobyl Shelter Fund * 5.1.2 The United Nations Development Programme * 5.1.3 The International Project on the Health Effects of the Chernobyl Accident * 6 Assessing the disaster's effectson human health * 7 Popular culture * 8 Commemoration * 8.1 Chernobyl 20 * 8.2 Tourist Destination * 9 See also * 10 Further reading * 10.1 Documents * 11 References * 12 External links |
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[edit]Accident
On 26 April 1986, at 01:23 a.m. (UTC+3), reactor 4 suffered a catastrophic power increase, leading to explosions inthe core. This dispersed large quantities of radioactive fuel and core materials into the atmosphere[7] and ignited the combustible graphite moderator. The burning graphite moderator increased the emission of radioactive particles, carried by the smoke, as the reactor had not been contained by any kind of hard containment vessel . The accident occurred during an experiment scheduled to test a...