also for power generation, thus having a lasting impact on the civilian electricity market in the years to come. The United States Navy Nuclear Propulsion design and operation community, under Rickover's style On June 27, 1954, the Obninsk Nuclear Power Plant in the USSR became the world's first nuclear power plant to generate electricity for a power grid, producing around 5 megawatts of electric power. The world's first commercial nuclear power station, Calder Hall at Windscale, England was connected to the national power grid on 27 August 1956. In common with a number of other generation I reactors, the plant had the dual purpose of producing electricity and plutonium-239, the latter for the nascent nuclear weapons program in Britain. It had an initial capacity of 50 MW per reactor (200 MW total), it was the first of a fleet of dual-purpose MAGNOX reactors. The U.S. Army Nuclear Power Program formally commenced in 1954. Under its management, the 2 megawatt SM-1, at Fort Belvoir, Virginia, was the first in the United States to supply electricity in an industrial capacity to the commercial grid (VEPCO), in April 1957. The first commercial nuclear station to become operational in the United States was the 60 MW Shippingport Reactor (Pennsylvania), in December 1957. Originating from a cancelled nuclear-powered aircraft carrier contract, the plant used a PWR reactor design. Its early adoption, technological lock-in, and familiarity among retired naval personnel, established the PWR as the predominant civilian reactor design, that it still retains today in the United States. In 1957 EURATOM was launched alongside the European Economic Community (the latter is now the European Union). The same year also saw the launch of the International Atomic Energy Agency (IAEA). The first major accident at a nuclear reactor occurred at the 3 MW SL-1, a U.S. Army experimental nuclear power reactor at the National Reactor Testing Station, Idaho National Laboratory. It was derived from the Borax Boiling water reactor (BWR) design and it first achieved operational criticality and connection to the grid in 1958. For reasons unknown, in 1961 a technician removed a control rod about 22 inches farther than the prescribed 4 inches. This resulted in a steam explosion which killed the three crew members and caused a meltdown. The event was eventually rated at 4 on the seven-level INES scale. Another serious accident happened in 1968, when one of the two liquid-metal-cooled reactors on board