Power Plant Coal, Oil and Nuclear
Start with a pile of fuel. Get it all hot and bothered. Add water. Make steam. Turbine goes roundy round. Alternator goes roundy round. 'lectricity makes light bulb shine bright.
Life is good.
How do we make nuclear fuel hot and bothered?
Start off with a big honkin' atom. Lets say Uranium. All Uranium atoms have 92 protons in their nucleus. Thats what makes it Uranium. If it had 2 protons in its nucleus, it would be Helium. Anyway, along with the 92 protons, U also has around 140 some odd neutrons. The different number of neutrons is what gives us the different isotopes (U235, U238, U812
Now we all remember that like charged particles don't want to be around each other. Well, in order for the 92 protons to be nestled up nice and tight next to each other in this nucleus, something has to be holding these protons together. That something is called the Nuclear force. A physical analogy would be compressing a spring and keeping it compressed with a piece of safety wire. Cut the wire and all that energy is going to come out. Nuclear fission is the same way. Fission or split the nucleus and the energy that was used to hold the pieces together gets released.
No new bits and pieces are made, they just get rearranged.
Example: Start off with 1 U238 atom. This means we have 92 protons and 146 neutrons. We will ignore the electrons for right now. For some reason, it decides to split up, and it breaks up into a big chunk, a little chunk, and some crumbs. We end up with Dy161, K66, and 2 He4 and 3 neutrons. And, everybody is now moving away from where we started. We did not make any new matter and we did not destroy any matter, we just released some energy and rearranged things a bit.
Now the Dy161 is probably not happy with the way it is and will probably spit out some He4 (alpha particles) or neutrons to get to a more stable configuration. Same with the K66. Eventually everybody settles down.
When everybody is moving about, that is heat. Collect the heat, add water, and we have got steam.
What causes a nucleus to split or spit out stuff? Either it wants to, or more often, something hit it. A big clunky nucleus is not very stable. Add a neutron that is zipping along and runs into the nucleus, and that nucleus may just go to pieces. If neutrons from that fission bangs into another nucleus, and then more and more fissions happen, that's a Chain Reaction. If the chain reaction is under control, it is called a nuclear reactor. If it is not under control, then it is called a nuclear bomb.
Now, most of the zipping around particles don't hit a susceptable nucleus. And the ones that do manage to hit a nucleus, most of them don't trigger a fission either. Thats why the nuclear fuel has to be enriched with the right kind of U and it has to be arranged in the right physical configuration, and then they add all sorts of stuff to make sure it gets consumed in the right sequence, and doesn't get too hot and all those engineering types of things.
[This message has been edited by LarryC (edited 07-16-2006).]