Title, how can such a small amount of metal be so powerful/potentially destructive? How is the power extracted? What makes it so dangerous? Any other interesting facts?
In: Physics
The nuclei of atoms hold a lot of energy, in significant part because they are full of charged particles (protons) that repel each other pretty strongly – so the nuclear forces have to be *very* strong to hold atoms together. Since the forces are very strong (compared to the electromagnetic force, which holds the energy of chemical bonds), breaking or forming nuclear bonds can release huge amounts of energy compared to breaking/forming chemical bonds (which is what you would do if you burn fuel for energy).
As for how to extract that energy from radioactive/fissile elements like plutonium, there are two main approaches:
**Radio-thermal generators**: Radio-thermal generators, or RTGs for short are rather simple: they hold a radioactive material, which produces heat as it decays (since those nuclear bonds are being broken down over time). It’s essentially the nuclear analog to a slow-burning fire. RTGs are usually only used for powering things like spacecraft that need a self-contained power source, since the materials you need for good RTGs are often highly radioactive and difficult to produce.
**Nuclear fission**: This is what you commonly think of with nuclear power. Essentially, some (but not all) radioactive materials are *fissile*. Being fissile means that on top of decaying by themselves, you can also make them decay in a way that releases energy by hitting them with the right particle (usually a neutron). For materials like plutonium, the fission that happens when you hit them with a neutron makes it release more neutrons, which can then hit other plutonium atoms, fissioning them and releasing more neutrons and so on – this is what is called the chain reaction. Because every atom split can cause more than one other atom to split, this is a process that accelerated exponentially as long as there are enough atoms available to split, which is what makes nuclear power dangerous (and enables nuclear bombs) – you can release a lot of energy *very quickly*. In order to produce safe nuclear power, you need to control the amount of neutrons available to start fission events to keep fission at a steady rate (at which point you are producing continuous heat, which you can use to boil water to run turbines to produce electricity).
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