Fissioning Grenades?

There is no getting around the fact that nuclear physics is difficult.  Fission is a complicated process and is difficult to understand.  In my previous post, I presented some of the details of the fission reaction...but maybe it is better to take a step back and think about what fission looks like.

Let's look at it in a large scale situation.  Imagine that there is a field in front of you, and in that field, each placed about a foot apart from each other, are live hand grenades.  These hand grenades all have had their pins pulled and have been placed in the dirt in such a manner that they do not explode on their own, but if disturbed at all, will explode.  In this state, these hand grenades are "unstable" just like the nuclei which undergo fission.

Now, imagine that you are holding a BB gun.  You carefully take aim at a hand grenade somewhere in the grid and you shoot it.  Assuming that you hit a grenade, it will explode upon the BB's impact.  This is how a fission reaction is induced.  Think of the neutron as a BB.  If the neutron is fired fast enough, it will cause the unstable target nucleus (the grenade) to "explode."

Of course, since this grenade is located in proximity to so many others, its explosion will produce shrapnel and release a large amount of energy.  The explosion will cause the surrounding grenades to explode which will then cause the grenades surrounding them to explode, thus starting a chain reaction.  The fission reaction in a reactor causes the "exploding" nucleus to release a large amount of energy as well as more neutrons (kind of like the shrapnel).  The newly released neutrons go on to cause surrounding nuclei to fission as well, just like the grenades causing each other to explode.  Assuming that there are enough nuclei around which are capable of fission, the reaction will continue indefinitely, releasing large amounts of energy, until measures are taken to stop the reaction.  This is the basic idea of a nuclear reactor.