Hmm. According to the International Nuclear Event Scale, there have only been 2 events at the most severe level (7): Chernobyl and Fukushima. There was 1 even

Hmm. According to the International Nuclear Event Scale, there have only been 2 events at the most severe level (7): Chernobyl and Fukushima. There was 1 event at a rating of 6, which was a Soviet explosion in 1957. There was also the Three Mile Island accident, which cost a lot of money to clean up (~$1 billion) but I don't think the severity was anywhere near Fukushima. https://en.wikipedia.org/wiki/International_Nuclear_Event_Scale#Details https://en.wikipedia.org/wiki/International_Nuclear_Event_Sc...