Question

What type of "fuel" could be used in a nuclear fusion reactor, and why is this desirable?

Short answer

The most suitable and desirable fuel for nuclear fusion reactors is a combination of deuterium and tritium (D-T) due to their abundance, high energy output, possibility of breeding tritium within the reactor, and lower activation compared to fission reactions. Deuterium is abundant in water, while tritium can be generated from lithium found in rocks and seawater. A D-T fusion reaction produces a very high energy yield, approximately 17.6 MeV (million electron volts) per reaction.

Step-by-step solution

Introduction to Nuclear Fusion

Nuclear fusion is the process of combining two or more lighter atomic nuclei to form a heavier one, releasing a large amount of energy in the process. This energy can be harnessed in a nuclear fusion reactor to produce electricity. The key to efficient and sustainable fusion reactions is finding suitable fuel to power the process.

Possible Fusion Fuels

There are several isotopes of hydrogen that can be used as fuel for nuclear fusion. The most common and promising candidates for fusion fuel are: 1. Deuterium (D), also known as heavy hydrogen, which has one proton, one neutron, and one electron. 2. Tritium (T), another isotope of hydrogen, containing one proton, two neutrons, and one electron. The combination of deuterium and tritium (D-T) is the most widely studied and used fuel for nuclear fusion reactions. Deuterium can also be combined with itself (D-D) or with helium-3 (D-He3) for other fusion reactions, although the latter is a less abundant fuel.

Advantages of Deuterium and Tritium

The use of deuterium and tritium as fuels for nuclear fusion has several desirable properties: 1. Abundance: Deuterium is relatively abundant in nature, usually found in water, with a concentration of about 1 part per 6,500 of hydrogen atoms. Tritium can be generated from lithium, which is also relatively abundant and can be found in rocks and seawater. 2. High Energy Output: A D-T fusion reaction produces a very high energy yield, approximately 17.6 MeV (million electron volts) per reaction, making it highly efficient. 3. Breeding: When tritium is used as fuel with deuterium, it can be bred within the reactor, eliminating the need for a large external supply. 4. Lower Activation: Fusion reactors produce less radioactive waste than fission reactors, making them more appealing from an environmental and safety perspective.

Conclusion

In summary, the most suitable and desirable fuel for nuclear fusion reactors is a combination of deuterium and tritium due to their abundance, high energy output, possibility of breeding tritium within the reactor, and lower activation compared to fission reactions.