Nuclear Reactors

Nuclear power is an incredibly energy-efficient way of generating power. Nuclear reactors are still a new technology, and have not yet replaced coal power plants. With global warming (see a future article) continuing, let's just hope that this technology becomes commonplace.
The most important section of a nuclear reactor is the reactor core. The reactor core is filled with fuel rods, rods of metal filled with a nuclear fuel such as Uranium-235 and Plutonium-239. Among these "fuel rods" are "control rods." Inserting the control rods into the reactor further slows down the energy production, and pulling them out makes the reactor create more energy. Inserting them fully shuts down the reactor. See above image of fuel rods in top left corner(image courtesy of Atomic Energy of Canada Limited).
Within the fuel rods, an extremely powerful reaction takes place. One neutron (see a future article on parts of an atom) is shot into the fuel rod. When the neutron strikes an atomic nucleus, it splits the nucleus, releasing two mini-nuclei, more neutrons, and a large amount of heat. The extra neutrons break more nuclei, turning this into an autocatalytic reaction(one that sustains itself without outside aid).
In a Pressurized Water Reactor(or PWR, one of the most common types) water is pumped through the reactor core. As it is piped through the core, it is exposed to temperatures well above its boiling point. This water is exposed to high pressures(this is why is is called a Pressurized Water Reactor) to keep it from instantly converting into steam. It is then piped out of the reactor core and into the steam generator. There, it is allowed to vaporize. After becoming vapor, it is used to power turbines that convert the motion into electricity. Then the water is piped back into the reactor core. The water can be replaced with some other fluids, leading to many different kinds of nuclear reactors.
A rare but interesting kind of nuclear generator is the radiothermal generator(or radioisotope thermoelectric generator, RTG for short). These run by absorbing the energy of radioactive decay(a process in which radioactive materials slowly convert themselves into stable materials by releasing subatomic particles). The RTG absorbs the particle release. These are useful because they last for a long time and need very little repair work. These were used on the Cassini space missions. An image of the Cassini orbiter's RTG under inspection is in the top right(image courtesy of NASA).
Why not use nuclear power for all of our energy needs? The answer is that nuclear power is dangerous. After the Chernobyl Meltdown(a meltdown occurs when the reactor core breaks, causing an explosion) radioactive material was blown high into the atmosphere. The Chernobyl disaster wiped out the reactor and forced the resettlement of over 336,000 people. Four square kilometers of pine forest died. A 30 kilometer area around the site of the reactor was established. Reports of mutated animals were never confirmed, except for some odd whiteness(albinism) in some species of swallows. The area is now populated by animals, but still no humans.
Nuclear power is useful, but dangerous. Its your choice-is it worth the risk?

-DTV

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