How does D-T fusion reaction utilize its waste to create more fuel?

In summary, nuclear fusion reactions produce tritons and neutrons which can be recycled to generate more fuel in a D-T fusion reactor.
  • #1
Leo Liu
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In Britannica's article on nuclear fusion, I came across the following description of the recycle of triton and neutrons:
Although tritium does not occur naturally, tritons and alpha particles are produced when neutrons from the D-T fusion reactions are captured in the surrounding lithium blanket. The tritons are then fed back into the plasma. In this respect, D-T fusion reactors are unique as they use their waste (neutrons) to generate more fuel. Overall, a D-T fusion reactor uses deuterium and lithium as fuel and generates helium as a reaction by-product.

What puzzle me are why the tritons are produced from the D-T fusion reaction, given that the products are alpha particle, neutron, and energy; and how the neutrons can be recycled to generated more fuel. Could someone kindly explain the details of these processes to me, please?

Source: https://www.britannica.com/science/nuclear-fusion
 
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  • #2
The D-T reactions produces neutrons. If there is a lithium blanket, then there is a good chance it will be captured by lithium-6. Li-6 + n -> He-4 + H-3. The H-3 can then be processed and used as a feed for the D-T fusion.

There is also the Li-7 + n -> He-4 + H-3 + n reaction.
 
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What is interesting is how to call the Li7+n or Li6+n reaction. It is not fusion but is it fission?
Technically it seems like fission as a nucleus captures a neutron then the intermediate state eventually decays after a very very short time and the end products result + extra energy.
Or is it labeled decay ?
 
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  • #4
artis said:
What is interesting is how to call the Li7+n or Li6+n reaction. It is not fusion but is it fission?
Technically it seems like fission as a nucleus captures a neutron then the intermediate state eventually decays after a very very short time and the end products result + extra energy.
Or is it labeled decay ?
It is called fission, when the two products are more or less of equal size, e.g., n+6Li -> α +t, or spallation, when other smaller particles are emitted, e.g, (n,2n) reactions. Some reactions have high threshold energies, and some are very unlikely (low cross-section) compare to the main reaction.
 

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Related to How does D-T fusion reaction utilize its waste to create more fuel?

1. How does the D-T fusion reaction utilize its waste to create more fuel?

The D-T fusion reaction produces a significant amount of energy, but it also creates a lot of waste in the form of helium nuclei and high-energy neutrons. This waste is then used to create more fuel through a process called breeding. The high-energy neutrons are absorbed by a blanket of lithium, which then produces tritium, a key fuel for the fusion reaction.

2. What is the role of the blanket of lithium in utilizing waste for fuel in D-T fusion?

The blanket of lithium surrounding the fusion reactor plays a crucial role in utilizing the waste produced by the D-T fusion reaction. The high-energy neutrons produced by the reaction are absorbed by the lithium, which then undergoes a process called transmutation to produce tritium, a key fuel for the fusion reaction.

3. Can all of the waste produced by the D-T fusion reaction be utilized for creating more fuel?

While the D-T fusion reaction does produce a significant amount of waste, not all of it can be utilized for creating more fuel. Some of the waste, such as the helium nuclei, is inert and cannot be used for fusion. However, the majority of the waste, including the high-energy neutrons, can be utilized for breeding tritium and producing more fuel.

4. How efficient is the process of utilizing waste for fuel in D-T fusion?

The process of utilizing waste for fuel in D-T fusion is quite efficient. It is estimated that for every one unit of energy produced by the fusion reaction, around 10-20 units of energy can be produced through the breeding of tritium using the waste. This makes D-T fusion a highly sustainable and efficient source of energy.

5. Are there any potential drawbacks to utilizing waste for fuel in D-T fusion?

One potential drawback of utilizing waste for fuel in D-T fusion is the production of high-energy neutrons, which can be damaging to the materials used in the fusion reactor. This requires careful design and engineering of the reactor to mitigate any potential damage. Additionally, the process of breeding tritium from the waste is not 100% efficient and can result in some loss of energy. However, these drawbacks can be overcome through continued research and development in the field of fusion energy.

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