How Does Nuclear Power Work - Part 1

This is the first of a series of articles concerning the situation at the nuclear power plants in Japan.  I’m keeping it simple for two reasons.  The first is length; the second is the fact that most people don’t know much about it.  So going into detail would likely go over most people’s heads.  Still, if anyone wants more info, I’ll do my best to provide it.  I guess a third reason is that going into a lot of detail would also require me to do some review so as I don’t provide confusing information.  But again, I’m more that willing if anyone asks.  Here it goes.

First thing to keep in mind is that all non-renewable power  (coal, gas, oil, nukes) all amount to fancy ways to boil water.  The only difference is how the heat is being generated.  Nuclear of course generates an awful lot of energy for the mass involved. 

We start with a bunch of uranium.  There are numerous different versions of this element that are found in nature and still others that are produced through enrichment processes.  Most reactors need one kind of enriched uranium or another.  Some, such as the CANDU reactors used in Canada can pretty much process the raw ore and can even be refueled online.

But I’m getting ahead of myself.  Why uranium?  Uranium is a heavy element.  If you look at a periodic table, you will see that it is way down there with a big dang number.  The bigger the number, generally the more unstable the element is.  That is, it naturally decays into something else, emitting energy in the form of subatomic particles.  This is what makes it useful for nuclear power.  Get enough of it in one contained place, such as a nuclear reactor core and what happens is that the particles emitted through natural decay get absorbed by other uranium atoms, rendering them more unstable so that they decay faster, and so on until the energy is enough that that atoms split, releasing a ton of energy and leading to a self-sustaining reaction.  The reaction is controlled by a combination of controlling the temperature and pressure of the coolant, altering the amount of boron (which absorbs neutrons emitted by the fission reactions and helps slow the reaction) and control rod position (which are also loaded with neutron absorbing material).

Next, we'll  look at the difference between a PWR and a BWR reactor.