Nuclear Power Plant Model

image from here

Nuclear power plants work almost exactly like hydroelectric power plants, except they use controlled fission to make steam which turns the turbines, rather than using gravity and water to turn the turbines. Once we understood the nuclear reactor, it was easy to visualize because we'd already talked so much about hydroelectric power during our water unit.

To help us visualize the fuel rods (small pellets of enriched uranium, arranged in a row inside metal rods), we put black beans into straws to make our own "fuel rods."

They bundle up bunches of these rods to make a fuel assembly for the reactor. In between them is a moderator (a liquid that slows the free neutrons down, such as "heavy water" [large percentage of deuterium in the Hydrogen]) and some control rods that can be raised or lowered to absorb neutrons and slow the chain reaction as needed. It's really such an ingenious method; I don't know how they figured it out!

Anyway, once we had our control rods made, the older boys would not rest until we had finished modeling the entire power plant, including the reactor. It was really fun finding things around the house that we thought were good representations of the various parts.

I don't know if you can read the labels very well (maybe if you click to enlarge this) but at left we have the containment dome, holding fuel rods (where fission occurs) and control rods. The superheated water generated here rises into the steam tank, where it turns that water into steam. The steam goes out through a steam line and turns the turbine, which in turn spins the generator (magnets + wire to create electrical current). The electricity then goes through a transformer (represented here by a Transformer, ha ha; the boys thought they were SO funny) and from there into the power lines where it lights up the flashlight at the end of the paper. Meanwhile, the steam goes into the cooling towers (vases) and much of it escapes out the top as water vapor. As it cools it flows back to the condenser, which turns the rest of it back into cool water so it can re-enter the steam tank to be heated again. There's also a reservoir of cool water nearby to add more water to the system as needed.

Pretty cool, eh? The boys were so proud of themselves. They wanted to keep their model around forever, but it was on the floor, so, with Junie and Daisy walking around, it had a very short life. (Half-life?) :)