A submarine engine choice shaped most of the world's nuclear power plants
When the U.S. Navy needed a reactor for USS Nautilus, it picked the pressurized water design because it was compact, simpler and easier to run in a cramped hull. The submarine went to sea in January 1954, and that naval decision made the pressurized water reactor the default for civilian power stations too.
The path began with physics. Fission was discovered in 1938, and within a year experiments confirmed that neutrons from one splitting nucleus could trigger others in a chain reaction. With war looming, that research fed weapons programmes. Chicago Pile-1, built beneath the Stagg Field stadium, went critical on December 2, 1942, as part of the Manhattan Project. Peaceful electricity came later: EBR-I in Idaho lit up on December 20, 1951, producing about 100 kilowatts, and Eisenhower's Atoms for Peace speech in 1953 pushed for civilian uses.
The Soviet Obninsk plant became the first to feed a power grid on June 27, 1954, with around 5 megawatts. Britain's Calder Hall followed in 1956 as the first commercial station, though it also made plutonium for weapons. Global capacity climbed from under a gigawatt in 1960 to 300 gigawatts by 1990; during the 1980s a new reactor started up roughly every 17 days. After the 1973 oil crisis France built 25 plants in 15 years, and by 2019 nuclear supplied 71 percent of its electricity, the highest share anywhere.
Opposition grew alongside. Protests at Wyhl in Germany killed a planned plant in 1975, and rising regulation made construction slower and costlier; in the United States more than 120 reactor proposals were cancelled. The 1979 Three Mile Island accident and the 1986 Chernobyl disaster, which caused 56 direct deaths, hardened public resistance, and Italy phased out nuclear power entirely by 1990. The 2011 Fukushima Daiichi meltdowns, triggered when the Tōhoku earthquake and tsunami knocked out cooling power, stalled an expected revival and led Germany to plan closing all its reactors by 2022.
Supporters point to one of the lowest death rates per unit of energy and low life-cycle carbon emissions, while critics cite accident risk, waste and cost. In 2023 reactors generated about 9 percent of the world's electricity, second among low-carbon sources after hydropower, and most new builds are generation III designs in Asia.
Source: Nuclear power
