11 h 22 m, 29 set 1957 ano - Kyshtym, Russia: Mayak Powerplant

Descrição:

The Kyshtym Nuclear disaster was a radiation contamination incident that occurred on 29 September 1957 at Mayak, a Nuclear fuel reprocessing plant in the Soviet Union. It measured as a Level 6 disaster on the INES, making it the third most serious Nuclear disaster ever recorded behind the Chernobyl Disaster and Fukushima Daiichi Disaster. The event occurred in the town of Ozyorsk, a closed city built around the Mayak plant. Since Ozyorsk/Mayak was not marked on maps, the disaster was named after Kyshtym, the nearest known town.

http://www.processindustryforum.com/hottopics/nucleardisasters

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