Fusion not Fossil Fuels

By Emma G.


1. What are the different kinds of fusion?

There are several different types of fusion that we can use to create energy. Some are better than others, some are easier than others.

The easiest is the D-T fuel cycle. Hydrogen-2 (Deuterium) is an isotope of hydrogen and is very abundant. Hydrogen-3 (tritium) is an isotope of hydrogen as well, but is in limited amounts because of its radioactive half-life, 12.32 years. This means that in order to achieve this cycle one needs to make tritium out of lithium. A reactant neutron that produces energy is created from the D-T reaction.

Next is the D-D fuel cycle, it is more difficult to do than the D-T fuel cycle. In this reaction you use deuterium and deuterium together. The energy for this is a bit higher than that in the D-T reaction, 15keV. The first branch creates tritium not neutrons, so the reactor will not be tritium free. Almost all of the tritium is burned up before it leaves the reactor so you don’t have to deal with handling so much tritium. Also more neutrons are made that are very high in energy.

Then comes the D-3He fuel cycle, this new method of fusion combines helium-3 and deuterium. This creates a helium-4 nucleus plus a high energy proton. The energy from this process is releashed in charged particles. Meaning a less activated reactor and more harvested energy.

The best option for aneutronic fusion is the p-11B fuel cycle, hydrongen-1 (proton)/boron. The side reactions produce 0.1% of the power carried by neutrons. Since most of the confinement properties are borderline, propositions for aneutronic fusion have radically different methods, like dense plasma focus.

2. What are the advantages of fusion?

If we used fusion it would create more power than any other  technology we use today, plus the fuel exists abundantly in the ocean. 1 in 6500 hydrogen atoms in the sea are deuterium. This seems low, but fusion reactions make so much more energy than chemical combustion. Sea water is very easy to obtain and more abundant than oil. Fusion could supply the world with energy for millions of years.

Even though fusion is not renewable, but it has many benefits of a renewable source. Also it has some of the pros of hydrocarbons and nuclear fission. Like oil, fusion would provide power generation and uninterrupted production. The cost of production is unaffected by changes in the economy. For example, water and wind energy costs go up. Fusion on the other hand, the production cost does not increase much when large plants are built.

3. Does fusion create radioactive waste?

Radioisotopes’ half-life made from fusion are like those from fission. In fission reactors the waste is radioactive for thousands of years, but in fusion the waste is only radioactive for fifty years. Plus most of the waste would be the reactor itself. Even though the waste would be more radioactive than fission waste, it has a very short half-life so managing the waste is relatively easy.

The materials used in a fusion reactor are more natural than that in fission. This means that the materials are selected to be low activation. In summery, fusion reactors make less radioactive waste than fission and the created material is less biologically damaging.