Light water and heavy water

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If you're supposed to explain light and heavy water in school, you will need to dig a little further. The definitions are based on the isotopes of the hydrogen atom.

Light and heavy isotope of Hydrogenium

You certainly have some basic knowledge of chemistry and also know that Periodic table:

  1. Use the periodic table to show the elements are arranged according to their atomic number. This also largely defines the chemical properties. The same atomic number therefore also means the same element.
  2. In addition to positive protons, atomic nuclei also contain neutrons, for example He (helium) contains two protons and 2 neutrons.
  3. If there are different variants of an element with different mass numbers, these are called isotopes. The term nuclide can also be used, as this is uncommon so there is no need to mention it.
  4. Hydrogen always contains a proton, but it can be 0. Contains 1 or 2 neutrons. Mention that there are the isotopes deuterium (1 neutron) and tritium (2 neutrons).
    5. What is an isotope in chemistry?

    Isotopes are the "varieties" of the elements. Who is a little closer to the structure of the ...

Light water is the oxide of the lightest isotope of hydrogen. So explain that our normal water is chemically light water because it is the oxide of the lightest isotope of hydrogen.

There are different heavy waters

As you can easily show from the previous explanations, there are purely theoretical different forms of heavy water.

  1. The isotope of hydrogen, which consists of a proton and a neutron, is called 2H or also referred to as D for deuterium.
  2. Now point out the different ways you can oxidize deuterium to water. There can only be an H through that 2H isotope to be replaced. Instead of H2O the isotope HDO. This water is known as semi-heavy water also hydrodeuterium oxide. This substance also occurs in nature.
  3. Another way to produce heavy water is when both H are through 2H, you get D then2O Deuterium Oxide, which is called heavy water. This substance also occurs in nature.
  4. You should definitely also explain the term superheavy water, where 3H is used instead of H. 3H is also known as tritium, so superheavy water is also tritium oxide. Unlike deuterium, tritium is radioactive because the isotope breaks down to helium, releasing an electron. Beta radiation is released.

In this context, it is important to mention that non-radioactive heavy water can be converted into radioactive heavy water by bombarding it with neutrons.

Light and heavy water in nuclear power plants

In nuclear power plants, fast and slow neutrons are separated from the fuel rods. Since slow neutrons trigger new nuclear fission significantly more often than fast ones, the fast neutrons are slowed down by water.

  • A light water reactor is therefore filled with completely normal water, which, however, tends to trap neutrons. For this reason, fuel rods made from enriched uranium are used in light water reactors.
  • Heavy water reactors contain heavy water. This does not tend to capture neutrons, which is why these reactors can be equipped with natural uranium.

Now that you know the distinction between light water and heavy water, you know that no radioactive water is used in these reactors. However, since deuterium also tends to trap further protons, radioactive tritium is always produced in a heavy water reactor. While this is not necessarily part of the definition, it should be mentioned anyway.

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