From Obninsk to the World Grid

The nuclear power era began in June 1954 when the 5 MWe Obninsk reactor in the Soviet Union fed its first kilowatt hours into a public grid. Calder Hall in Britain followed in 1956 and Shippingport in the United States in 1957.

Those three plants proved concepts that grew into roughly 440 power reactors across about 30 countries. Nuclear energy now supplies about 9 percent of world electricity and is the second largest source of low carbon power after hydro..