Item 2 is very important. This energy will be converted into electricity (we’ll see how in a later experiment).

    Item 3 is absolutely vital. For these emitted neutrons make it possible to produce a steady stream of nuclear energy. Why? When one U-235 atom splits, the neutrons it releases cause other U-235 atoms to split. The additional neutrons released trigger still other U-235 atoms. And on and on it goes. This kind of process is called a chain reaction.

    Imagine a chunk of U-235 in which a chain reaction has begun. If the reaction takes place quickly enough, an enormous amount of energy is released.

    You can demonstrate this type of rapid-fire chain reaction by setting up your dominos as shown in the first domino drawing. When you tip the leading domino over, as if shooting a neutron bullet into uranium, it tips two other dominos over (releases two new neutrons). In turn, the two falling dominos tip over four more. And the uncontrolled chain reaction goes to completion.

    But in a nuclear power plant, a runaway chain reaction — that is, an “atomic bomb” explosion — is impossible. Nuclear power plants control the reaction. Here’s how it’s done:

    The heart of a nuclear power plant is a nuclear reactor. Without getting bogged down in details, a reactor contains bundles of nuclear fuel (U-235) separated by materials that absorb neutrons. Thus when a U-235 atom splits, all but one of the neutrons are absorbed before they can  reach  other  U-235  atoms.  The  single  remaining neutron is available to split another U-235 atom.    

The result is a steady release of energy over a long