by Eli West
Guest Host
Liquid Thorium Reactor
The word “nuclear” means a lot to us today. When we hear it we think of many things: bombs, reactors, uranium, “nuculur,” and radioactive; all of these are connotations of the word nuclear. Let’s explain what each of them means.
We’ll begin with bombs. The common link between nuclear and bombs, is obviously, nuclear bombs; otherwise known as atom bombs. In essence, you have a collection of uranium atoms; specifically Uranium-235, which is very fissile. In a bomb, a lone neutron is shot at a uranium-235 atom to create uranium-236. Since uranium-236 is too unstable, the isotope breaks apart very violently, shooting neutrons everywhere, and these reactionary neutrons in turn smash into other uranium-235 atoms, and those atoms break apart and smash OTHER atoms. Which is what makes atomic bombs so explosive.
Another think we link to nuclear is uranium. Uranium is a very heavy atom. With a standard atomic weight of 238.03 g/mole, it’s on the heavy side. However, you’re probably used to hearing terms like uranium-238 or uranium-235. What do the numbers mean? Why are they different? What does it change? The number with uranium is indicating the isotope number, which simply means that there are more or less neutrons with the same number of protons. The 238 number gives you the atomic weight of the atom. In order to find out how many neutrons there are, you simply take the atomic number (which is 92, the number of protons in all uranium atoms, regardless of isotope), then take the atomic weight minus the atomic number to find the number of neutrons. In this case it is 238-92=146. So we know that there are 146 neutrons in each atom of uranium 238. Compared to hydrogen, that’s heavy.
Nuculur. I’m not even going to go into that, except to say that the correct pronunciation, by the way, is “new-clear.”
Radioactivity: it’s a word with a history. It’s a word that’s gotten a pretty bad rep over the years, through romanticizing, myths, and fiction. Everyone has heard the stories of people getting hit with gamma radiation and gaining super powers! Or of radiation being like the Black Death, destroying any who get near. The truth is, EVERYTHING is radioactive. Now don’t get scared! That term isn’t quite as bad as believed! Let’s get a few things straight, what exactly does, radiation mean? Well, everything radiates. EVERYTHING. Radiation is just the constant output of energy. We radiate heat, and light, just like the sun; food radiates heat! Some things just radiate such high-energy waves that they become dangerous. THAT is radioactivity.
“Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability.”
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html
Thorium concentrations in the USA
Now, where I am going with all this is thorium. What is thorium? It’s an incredibly heavy atom, much like uranium. It has large isotopes, much like uranium. Both of them have a huge half-life, and are highly radioactive; the differences between them are: (1) uranium, when used in nuclear reactors, produces a new isotope of uranium, which can be weaponized in the form of depleted uranium. It can be formed into what are essentially large bullets crafted out of the depleted uranium isotope. The bullet is incredibly dense, and when shot at high enough velocities, can pierce tank armor. It doesn’t explode in a nuclear bomb, but it does spray radioactive uranium all over the inside of the target tank. Thorium, on the other hand, when used in a nuclear reaction will not produce a weaponizable material. Thorium and uranium are both naturally occurring materials.
Thorium is abundant compared to uranium. So as a fuel source it would be cheaper, MUCH cheaper. Thorium is not fissile itself, which means it cannot sustain a low energy chain nuclear reaction, which means that it is not actually usable in nuclear reactors by itself. However, it is fertile, which means slow neutrons can be added to it to change it into U-233 (or uranium-233), which is fissile. That’s why we can’t just start mining thorium and tossing it in nuclear reactors all over the world. First we need to create reactors that can change it into U-233, which would then be fissile.
Thorium deposits in Alaska
The word thorium has a very simple background. The man who discovered thorium simply decided that Thor was a pretty cool guy, and that maybe he should call this thing thorium!
As of right now there are a few companies around the world that are developing thorium reactors. Their projections for finishing the project are around 2015. That’s five years. Not to mention the actual two or three years it would take to build each reactor. So, the technology is coming, but is a ways off. Some believe that once they get the reactors running, that we could wean the world off oil in as little as five years, or by 2020. However, that’s probably a bit optimistic, and there still is a lot of work before we reach that point.
The Elements Unearthed 