Uranium

Uranium is a naturally occurring radioactive metal, atomic number 92, that supplies the fissile material burned in nuclear power reactors worldwide. The German chemist Martin Heinrich Klaproth identified it as a new element in Berlin in 1789, naming it for the recently discovered planet Uranus; for more than a century afterward it was valued chiefly for coloring glass and ceramic glazes, since its capacity to release energy through nuclear fission was not understood until the twentieth century. Natural uranium is a metal about as common in the Earth's crust as tin or zinc, though only its uranium-235 isotope, roughly 0.7 percent of the natural mix, sustains the chain reaction that heats water into steam inside a reactor; most commercial fuel is enriched to raise that share. Australia, Kazakhstan and Canada lead world uranium production today.