Nuclear power station at night. Storm clouds and lightning are seen at left. This nuclear power station has six pressurized water reactor (PWR) towers. These use mixed oxide fuels (MOX), a mixture of 5% plutonium and 95% depleted uranium. Each of the six towers produces 900 megawatts (MW) of electricity. Nuclear power stations utilise fission, the splitting of large atoms to release neutrons and energy, in controlled chain reactions. This is the Gravelines nuclear power station near Calais, France.