Chernobyl disaster facts for kids

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Chernobyl radiation map 1996
A map of caesium-137 contamination in 1996, a decade after the Chernobyl crisis. Restriction orders are still in place for the production, transportation and consumption of food contaminated by Chernobyl fallout
Chernobyl-4 and the Memorial 2009-001
Chernobyl Nuclear Power Plant reactor number 4, the enclosing sarcophagus and the memorial monument, 2009

The Chernobyl disaster was a nuclear disaster which occurred on 26 April 1986 at the Chernobyl nuclear power plant in Pripyat, Ukraine. At that time, Ukraine was part of the Soviet Union.

The event was the worst accident in the history of nuclear power. Because there was no containment building to trap the radiation, radioactive fallout drifted over parts of the western Soviet Union, Eastern Europe, Scandinavia, the UK, and the eastern United States. Large areas of Ukraine, Belarus, and Russia were badly contaminated. About 60% of the radioactive fallout landed in Belarus. About 350,000 people needed to be evacuated (moved away) and moved to other places where they could live after the accident.

Before the accident, there was a planned power reduction. By the beginning of the day shift, the power level had reached 50%. Following this, randomly, one of the regional power stations went offline. It was then requested that the further power reduction would be postponed. Despite this request, the reduction and preparations for a test that was to happen continued.

The accident occurred when the fourth reactor suffered a huge power increase. This led to the core of the reactor exploding. Due to this explosion, large amounts of radioactive materials and fuel were released into the atmosphere. This lit the combustable graphite moderator on fire. This fire greatened the release of radioactive material, which was carried by the smoke of the fire, into the environment and atmosphere.

Reactor 4 is now covered by a "sarcophagus", made from steel and concrete to stop the escape of more radiation from elements such as corium, uranium and plutonium, as well as radioactive dust. The sarcophagus is to be replaced with the New Safe Confinement structure.

The accident raised concerns about the safety of the Soviet nuclear power industry. The Soviet Union slowed down the process of making its nuclear industry bigger for some time. The Soviet government also had to become less secretive as a result of the accident. Since then, Russia, Ukraine and Belarus have become separate countries. Those countries have been burdened with continuing costs for decontamination (removing the radiation) and health care because of the accident. Exposure to radiation leads to a higher risk of getting cancer. It is difficult to accurately tell the number of deaths caused by the events at Chernobyl. The Chernobyl accident happened when some workers were testing the safety of the reactor. Some of the devices that stopped the reactor from blowing up were switched off. Then, there was a power surge; they lost control and the reactor blew up.

Most of the people affected have not died yet. When and if the people involved die of cancer, or related diseases, it will be hard to tell if this was because of the accident. A 2005 IAEA report tells of 56 direct deaths; of those, 47 were accident workers and 9 were children who died of thyroid cancer. The report estimates that up to 4,000 people may die from long term diseases related to the accident. Greenpeace, along with others, thinks that the study's conclusions may be false.

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