Technically, there are two kinds of nuclear power—fusion and fission. Humans have not quite figured out how to make an efficient fusion reactor, so let me focus on a fission reaction. The fission reactor starts with a heavy atom like uranium-235 and hits it with a neutron. The atom absorbs this neutron to become uranium-236. However, U-236 is unstable and breaks into smaller parts—maybe palladium-117 and a palladium-118 plus some neutrons. But here’s the weird part: If you look at the mass of the original U-236 and the mass of all the pieces, they aren’t the same. The mass of the two palladium atoms plus neutrons is less than the mass of the uranium. So, mass isn’t conserved—but energy is. This is where the famous E = mc2 equation comes from, where c is the speed of light (about 3 x 108 m/s).
A loss in mass in the system of particles just means that there is an increase in some other type of energy. In this case, it’s an increase in kinetic energy of the resulting particles. Since the value of c is so large, a tiny decrease in mass results in a huge increase in kinetic energy. Now you can use that energy to … wait for it … heat up some water and make steam. This steam is then used to turn an electric turbine (don’t pretend to be surprised). But remember, you are getting this energy just by converting mass into energy—it’s so crazy, it almost looks like you are getting energy for free.
Although it might seem like a perfect way to get some electrical energy, there is one small problem. You now have this leftover palladium and stuff that’s both radioactive and chemically active. No one wants to be around dangerous radioactive chemicals, but this nuclear waste has to be stored somewhere safe. It’s not as simple as putting it in a box and burying the trash, because it can remain radioactive for thousands of years. Imagine building a box that keeps stuff contained for that long and you see the problem. But it’s the price you pay for seemingly “free” energy.
So, which power plant is the best? At this point, there’s no clear answer—except that fossil fuels are probably the worst choice. Hopefully we can figure something out for the future.
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