<P> In the United States, where Fermi and Szilárd had both emigrated, this led to the creation of the first man - made reactor, known as Chicago Pile - 1, which achieved criticality on December 2, 1942 . This work became part of the Manhattan Project, a massive secret US government military project to make enriched uranium by building large reactors to breed plutonium for use in the first nuclear weapons . The US tested atom bombs and eventually these weapons were used to attack the cities of Hiroshima and Nagasaki . </P> <P> In 1945, the first widely distributed account of nuclear energy, in the form of the pocketbook The Atomic Age, discussed the peaceful future uses of nuclear energy and depicted a future where fossil fuels would go unused . Nobel laurette Glenn Seaborg, who later chaired the Atomic Energy Commission, is quoted as saying "there will be nuclear powered earth - to - moon shuttles, nuclear powered artificial hearts, plutonium heated swimming pools for SCUBA divers, and much more". </P> <P> The United Kingdom, Canada, and the USSR proceeded to research and develop nuclear industries over the course of the late 1940s and early 1950s . Electricity was generated for the first time by a nuclear reactor on December 20, 1951, at the EBR - I experimental station near Arco, Idaho, which initially produced about 100 kW . Work was also strongly researched in the US on nuclear marine propulsion, with a test reactor being developed by 1953 (eventually, the USS Nautilus, the first nuclear - powered submarine, would launch in 1955). In 1953, US President Dwight Eisenhower gave his "Atoms for Peace" speech at the United Nations, emphasizing the need to develop "peaceful" uses of nuclear power quickly . This was followed by the 1954 Amendments to the Atomic Energy Act which allowed rapid declassification of US reactor technology and encouraged development by the private sector . </P> <P> On June 27, 1954, the USSR's Obninsk Nuclear Power Plant became the world's first nuclear power plant to generate electricity for a power grid, and produced around 5 megawatts of electric power . </P>

When was nuclear power first used to generate electricity