Magnox is a type of nuclear reactor that uses magnesium alloy cladding to contain the nuclear fuel. It was developed in the United Kingdom in the 1950s and primarily uses natural uranium as fuel. The design allows for the efficient production of electricity while also generating plutonium for use in nuclear weapons. The Magnox reactors are known for their simplicity and low operating costs. They use carbon dioxide as a coolant and can operate at relatively low temperatures. Although many Magnox reactors have been decommissioned, they played a significant role in the early development of nuclear power in the UK.