* Astronomy

Calder Hall was the world's first nuclear power station to deliver electricity in commercial quantities (although the 5 MW "semi-experimental" reactor at Obninsk in the Soviet Union was connected to the public supply in 1954).
First connection to the grid was on 27 August 1956, and the plant was officially opened by Queen Elizabeth II on 17 October 1956.
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The first Magnox reactors at Calder Hall were designed principally to produce plutonium for nuclear weapons. The production of plutonium from uranium by irradiation in a pile generates large quantities of heat which must be disposed of, and so generating steam from this heat, which could be used in a turbine to generate electricity, or as process heat in the nearby Windscale works, was seen as a kind of "free" by-product of an essential process.
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