The United States was not the only country with nuclear power ambitions. The Union of Soviet Socialist Republics, under the leadership of Stalin, built a new science city, Obninsk, 68 miles (110 km) southwest of the capi­tal, Moscow. On January 1, 1951, construction began in Obninsk on the AM-1 nuclear power station. It was not a highly innovative design, as it used the reactor configuration and material choices from the wartime plutonium reactors built in Hanford, Washington, from information gained by expertly executed espionage. First startup was on June 1, 1954, coming up to full power and connecting to the electrical power grid 25 days later. It produced only five megawatts of electricity, hardly enough for half the town of Obninsk, but it was still the world’s first civilian power station.

With its graphite moderator combined with water cooling and its use of inexpensive, natural uranium fuel, the reactor was not designed for optimum safety, but it would be a prototype for more ambitious Soviet plans. Its design would be scaled up into large, practical power-produc­tion reactors, each generating 1,500 megawatts of electricity, named the RBMK, reaktor bolshoy moshchnosti kanalniy, or the channel-type high — power reactor. The explosion and meltdown of an RBMK near the town of Chernobyl on April 26, 1986, would change the course of nuclear power development worldwide, as the severe radiation release led to the perma­nent evacuation of the town and its surrounding area. The Chernobyl inci­dent involving RBMK-4 would be the worst nuclear accident in history.

Great Britain after World War II had the advantage of having partici­pated with the United States in the intense wartime nuclear development, and British scientists returned home with ideas and plans for making their country part of the new atomic age. Although in 1946 the United States had closed its nuclear programs to all other countries, the British government started an independent weapons and power program at the Windscale facility, near the village of Seascale, on the Cumbrian coast. Their first nuclear reactors were two plutonium-production units, Wind — scale Piles 1 and 2. In retrospect, these were probably the least safe reactors ever built, with less safety margin than the Soviet AM-1. Unlike Rickover’s