Magnox reactors are a type of nuclear reactor that use natural uranium as fuel and graphite as a moderator. They were developed in the United Kingdom in the 1950s and are named after the magnesium alloy used to encase the fuel rods. These reactors are designed for electricity generation and can also produce plutonium for nuclear weapons. The first Magnox reactor began operation in 1956, and several were built in the UK and other countries. They are known for their simplicity and reliability, but many have been decommissioned due to age and the availability of more advanced reactor designs.