Plutonium is a chemical element with the symbol Pu and the atomic number 94. It is a hard, white metal that resembles iron. The forms of plutonium most commonly used in the nuclear industry are Pu 239, Pu 240 and Pu 241.
Originally, Pu 239 was formed during the creation of the universe!
So how the nuclear industry can use Pu 239, you may wonder… The answer is simple: it is produced by the nuclear reaction from the uranium used as fuel. In this reaction, uranium-238 captures a neutron and transforms into uranium-239. In turn, the uranium-239 converts to neptunium-239 by losing an electron. Then, in the same way, the neptunium-239 transforms into plutonium-239. After a mechanical and chemical treatment of the used fuel in a specialized plant (Orano la Hague plant), the recovered plutonium is recycled in nitrate form and then converted into the oxide (PuO2).
By way of analogy with the earlier discoveries, uranium and neptunium – whose names owe their origin to the planets Uranus and Neptune – the name plutonium, given to the element in 1942, is a reference to the planet Pluto, situated beyond Uranus in our solar system.