(ELI5) I just read that plutonium is very rare. I have little to no knowledge of science etc. where in the natural world does it come from? How do you source it?

Question

(ELI5) I just read that plutonium is very rare. I have little to no knowledge of science etc. where in the natural world does it come from? How do you source it?

In: 3

Answer 1

Chemical elements are collections of protons (positively charged particle), neutrons (as the name suggest, particles with no net electric charge) and electrons (negatively charged little devils).

What makes elements different is the number of protons: hydrogen has one proton, helium has two and so on up the periodic table. This property is also known as the “atomic number”.

The heavier elements such as Uranium, Plutonium have atomic numbers of 92 and 94, respectively.

Now, elements with a given atomic number but exists as several variants with different numbers of neutrons are called isotopes. Some isotopes are long lived and stable, and some are unstable and quickly break up into other things. This is what we mean by “radioactive”: the isotope is unstable and emits radiation to turn into different isotopes or entirely into chunks of different elements with smaller atomic numbers.

Crucially, this property goes the other way too: you can grab an isotope of, say, Uranium-238, a commonly found isotope of Uranium that is non fissile, bombard it with deuterium (essentially a hydrogen that has a neutron in addition to its usual single proton), and voila, you obtain Plutonium when the Uranium captures two protons to go from an atomic number of 92 to one of 94.

It is a bit more involved than this, with the first product of the reaction being neptunium that subsequently decays into Plutonium-238, but you see the picture. In fact this is how Plutonium was first synthetically made. This process can also occur naturally: any Uranium-238 occurring naturally may capture some decay products from other decaying Uranium (or other isotopes), and voila, you have naturally occurring Plutonium. That process however is exceedingly rare, which is why Plutonium occurs naturally only in trace amounts.

The number in “Uranium-238” or “Plutonium-238” is the “mass number”, the sum of the number of protons and that of the neutrons.

Edit: spelling.