Ch. 03 – All Things Nuclear (Part 4)

The only significant exception to solar-generated electricity is energy derived by releasing the binding energy of atoms, either as fission when we split heavy atoms like uranium, or as fusion when we combine light atoms like hydrogen. We are expert at the first, but we haven’t quite figured out how to accomplish the second.

An examination of atomic power – nuclear energy – would not be replete without a discussion of the twin “problems” of radiation and nuclear waste. First we will tackle radiation. Then, after we develop a good understanding of how nuclear reactors work, what they are and, what they are not, we’ll spend some time talking about nuclear waste.

Radiation

Step outside on a nice day and feel the sun’s warmth – that’s radiation; so is the light. A body’s warmth is radiation. So are radio waves, television signals, X-rays, and light from a glowworm’s tail.

Radiation is energy transfer. It can take several forms. One is tiny mass-less packets called photons. We experience photons most commonly as ordinary light. This radiation frequently is called electromagnetic radiation. Photons carry energy, and the more energetic they are – the higher their frequency – the more “dangerous” they can be. Harm results when energy is transferred to living cells in a damaging way. Early atomic scientists identified a form of radiation they called “gamma-rays.” Ironically, this radiation turned out to be nothing more than high-energy photons, but the name still is frequently used. So when certain reactions produce high-energy photons, instead of referring to them as “high-energy photons,” scientists usually call them “gamma-rays,” but they are identical.

In 1895 William Roentgen discovered a form of radiation that has become known as X-rays. Not very long thereafter, scientists determined that X-rays were energetic photons with less energy than gamma-rays but with more energy than ultraviolet light.

In school we all learned about the atomic nucleus surrounded by a cloud of electrons. Most of us probably carry a mental picture of a little solar system with a sun-like nucleus surrounded by electrons representing the planets. Keep this useful analogy in mind as we move forward.