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On September 29, 1957 the Mayak nuclear fuel reprocessing plant, located near Kasli in Russia, was the site of an enormous explosion which released serious amounts of radioactive materials into the environment. Almost 500,000 people were exposed to dangerous levels of radiation, and 200 people were killed.

How did it happen

The explosion was centered in a radioactive waste storage facility located at Mayak. The tanks were located underground, and the waste that was stored in them was kept there for a period of up to a year before being reprocessed. A cooling system failure occurred in one of the tanks, which caused all of the coolant in the facility to evaporate. Gradually, the tanks began to heat up, and when the temperature hit 350 C the explosion occurred. It hit with such force – estimated at 75 tons of TNT – that 20 million curies of radiation were released into the immediate area. This radioactive material either remained in the atmosphere, where it formed a large cloud that moved through the Russian province of Chelyabinsk, and fell down upon the occupants in a 23,000 square kilometer radius.


The poisonous effects of the radiation were stunning. 10,000 people were evacuated, but by the time that had occurred 270,000 people in the immediate area had been exposed to high amounts of radiation. As the cloud of radioactivity spread, this number grew to 470,000. 200 people died from firsthand effects of the accident, while thousands of others would grow sick over the ensuing years. Agriculture in the area was also seriously affected, with plants and livestock dying off and the ground essentially polluted beyond recovery. Millions of tons of top soil were scraped up and disposed of, and much of the existing food supply in the region had to be destroyed due to contamination by radioactivity.

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