I’m half way through watching the new HBO / Sky miniseries Chernobyl. Have you seen it? Here in the UK it has received some great reviews with some critics claiming it is the best TV series ever produced.

Chernobyl, as you probably know was a nuclear power station in the Ukraine that exploded with catastrophic consequences in 1986.

If you study option C, Energy you will look at nuclear fission and fusion in section C3. Chernobyl was a fission reaction. In a fission reaction, heavy atoms (eg, Uranium) with unstable nuclei undergo radioactive decay. This essentially means their nuclei breakdown as they are too large and become unstable.

They can breakdown in three different ways, by losing 2 protons and 2 neutrons (often referred to as He2+) – this is alpha radiation.

If a proton decays into a neutron and an electron, the electron is ejected from the nucleus – this is beta radiation.

Finally, where high energy electromagnetic radiation is emitted from the nuclei (referred to as gamma radiation).

All three types of radiation also generate a huge amount of energy per atom.

Alpha radiation is the least harmful and can be stopped by paper, beta radiation needs aluminium to stop it and gamma radiation needs a layer of lead to stop it.

Because of the different masses of the radioactive particles, alpha radiation moves the shortest distance and gamma the furthest.

Sometimes, alpha radiation is referred to as the least harmful with gamma the most harmful, but this is misleading. What is important is the size of the dose. A tiny dose of gamma radiation can be given when, for example, you have an X ray. A large dose of alpha radiation could be much more harmful than this.

Fission is the opposite of fusion. In fusion nuclei breakdown where in fission, nuclei are forced together (fused) to make new nuclei and new atoms. This is much harder said than done. Nuclei are positively charged and will repel each other. So the nuclei need to be put under considerable force.

When they fuse, they release energy, even more than is released during fission.

The conditions needed to fuse atoms together are hard to obtain. The sun is a giant fusion reactor and it is the immense gravity it generates that fuses hydrogen atoms together into helium atoms. Here on earth fusion reactors involve producing a plasma and using magnetic field to hold it in place.


Have you covered these concepts and ideas in the Energy option? If so, which aspects of it fission and fusion did you cover. Please feel free to post your comments below.