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"Fusion is in theory something that could give us true energy abundance." What does fusion give us that existing nuclear power plant tech doesn't?

drexlspivey 5y ago
The reactor can’t meltdown and contaminate the whole planet. Also there is no radioactive waste
- ziotom78 5y ago
  Well, there is some radioactive waste [1], but its decay time is far smaller and is thus far easier to handle. (Moreover, there is a larger choice of elements.) [1] https://en.wikipedia.org/wiki/Fusion_power#Radioactive_waste https://en.wikipedia.org/wiki/Fusion_power#Radioactive_waste
  - el_nahual 5y ago
    Aren't fast decay times harder to handle?
    - baq 5y ago
      it's easier in the sense that a single accident doesn't make the area uninhabitable in the human civilization timescales. fast decay = it'll kill you today in a minute, but will be safe to approach in a week, or 50 years.
kamaal 5y ago
>>What does fusion give us that existing nuclear power plant tech doesn't? Water is more abundant than Uranium?
- qPM9l3XJrF 5y ago
  Fair enough, I hope fusion plants aren't adjacent to bomb technology in that case? Because that could lead to a lot of nuclear proliferation.
nobody9999 5y ago
>What does fusion give us that existing nuclear power plant tech doesn't? The energy generated per unit mass in a fusion reaction is ~9 times that generated in a fission reaction[0]: Considering the mass of the four protons/hydrogen nuclei (4.029106u) and the mass of the Helium produced (4.002603u) we get a mass difference of 0.026503u or 24.69MeV. So it is easy to see that fusion reactions give out more energy per reaction. However, the energy per unit mass is more relevant. This is 0.7MeV for fission and 6.2MeV for fusion so it is obvious that fusion is the more effective nuclear reaction. Which leads to a great deal of confusion on my part as to why we're not spending enormous amounts of money on Fusion R&D. Given the potential of the technology, you'd think we'd have long ago decided to spend whatever was necessary to commercialize hydrogen fusion as a power generation mechanism. The phrase "electricity too cheap to meter" is likely somewhat hyperbolic, but in comparison to pretty much any other mechanism fusion is enormously more productive and efficient. [0] https://www.physlink.com/education/askexperts/ae534.cfm https://www.physlink.com/education/askexperts/ae534.cfm
- Firadeoclus 5y ago
  Would you be willing to elaborate why "energy per unit mass" matters when the mass in question is a completely different substance with different cost and availability profile? If we found a way to extract 10x as much energy from coal as we currently do, electricity from coal wouldn't become 10x cheaper, nor would we build power plants 10x as big.
  - nobody9999 5y ago
    >Would you be willing to elaborate why "energy per unit mass" matters when the mass in question is a completely different substance with different cost and availability profile? Sure. Specific energy (or energy per unit mass) between different types of materials makes a huge difference. For example (Source here[0]): Material Type of generation Specific energy (MJ/Kg) Hydrogen Fusion 639,780,320 Coal Oxidation 24.0-35.0 Note the specific energy of a Kg of burned coal compared with a Kg of fused hydrogen. Fused hydrogen generates roughly 200,000 times the energy per unit mass than burning coal. You're right. Cost and availability play into this as well. There are estimated to be ~1.06 trillion tons of coal on earth[1], hydrogen is the most abundant element in the universe and even makes up a significant amount of the mass of coal. Burning hydrogen/hydrocarbons is, compared to fusing hydrogen, an incredibly inefficient process. I'd say that being able to generate 200,000 times the energy per unit mass is an important consideration. As for availability, hydrogen is more abundant and cheaper to produce (unless you have petatons of plant matter, the right conditions and a few tens of millions of years at no cost to you) than any fossil fuels. Or just about anything else. [0] https://en.wikipedia.org/wiki/Energy_density#List_of_material_energy_densities https://en.wikipedia.org/wiki/Energy_density#List_of_materia... [1] https://www.worldcoal.org/coal-facts/what-is-coal-where-is-it-found/ https://www.worldcoal.org/coal-facts/what-is-coal-where-is-i... Edit: Clarified availability.

drexlspivey 5y ago

The reactor can’t meltdown and contaminate the whole planet. Also there is no radioactive waste

ziotom78 5y ago
Well, there is some radioactive waste [1], but its decay time is far smaller and is thus far easier to handle. (Moreover, there is a larger choice of elements.) [1] https://en.wikipedia.org/wiki/Fusion_power#Radioactive_waste https://en.wikipedia.org/wiki/Fusion_power#Radioactive_waste
- el_nahual 5y ago
  Aren't fast decay times harder to handle?
  - baq 5y ago
    it's easier in the sense that a single accident doesn't make the area uninhabitable in the human civilization timescales. fast decay = it'll kill you today in a minute, but will be safe to approach in a week, or 50 years.

kamaal 5y ago

>>What does fusion give us that existing nuclear power plant tech doesn't? Water is more abundant than Uranium?

qPM9l3XJrF 5y ago
Fair enough, I hope fusion plants aren't adjacent to bomb technology in that case? Because that could lead to a lot of nuclear proliferation.

nobody9999 5y ago

>What does fusion give us that existing nuclear power plant tech doesn't? The energy generated per unit mass in a fusion reaction is ~9 times that generated in a fission reaction[0]: Considering the mass of the four protons/hydrogen nuclei (4.029106u) and the mass of the Helium produced (4.002603u) we get a mass difference of 0.026503u or 24.69MeV. So it is easy to see that fusion reactions give out more energy per reaction. However, the energy per unit mass is more relevant. This is 0.7MeV for fission and 6.2MeV for fusion so it is obvious that fusion is the more effective nuclear reaction. Which leads to a great deal of confusion on my part as to why we're not spending enormous amounts of money on Fusion R&D. Given the potential of the technology, you'd think we'd have long ago decided to spend whatever was necessary to commercialize hydrogen fusion as a power generation mechanism. The phrase "electricity too cheap to meter" is likely somewhat hyperbolic, but in comparison to pretty much any other mechanism fusion is enormously more productive and efficient. [0] https://www.physlink.com/education/askexperts/ae534.cfm https://www.physlink.com/education/askexperts/ae534.cfm

Firadeoclus 5y ago
Would you be willing to elaborate why "energy per unit mass" matters when the mass in question is a completely different substance with different cost and availability profile? If we found a way to extract 10x as much energy from coal as we currently do, electricity from coal wouldn't become 10x cheaper, nor would we build power plants 10x as big.
- nobody9999 5y ago
  >Would you be willing to elaborate why "energy per unit mass" matters when the mass in question is a completely different substance with different cost and availability profile? Sure. Specific energy (or energy per unit mass) between different types of materials makes a huge difference. For example (Source here[0]): Material Type of generation Specific energy (MJ/Kg) Hydrogen Fusion 639,780,320 Coal Oxidation 24.0-35.0 Note the specific energy of a Kg of burned coal compared with a Kg of fused hydrogen. Fused hydrogen generates roughly 200,000 times the energy per unit mass than burning coal. You're right. Cost and availability play into this as well. There are estimated to be ~1.06 trillion tons of coal on earth[1], hydrogen is the most abundant element in the universe and even makes up a significant amount of the mass of coal. Burning hydrogen/hydrocarbons is, compared to fusing hydrogen, an incredibly inefficient process. I'd say that being able to generate 200,000 times the energy per unit mass is an important consideration. As for availability, hydrogen is more abundant and cheaper to produce (unless you have petatons of plant matter, the right conditions and a few tens of millions of years at no cost to you) than any fossil fuels. Or just about anything else. [0] https://en.wikipedia.org/wiki/Energy_density#List_of_material_energy_densities https://en.wikipedia.org/wiki/Energy_density#List_of_materia... [1] https://www.worldcoal.org/coal-facts/what-is-coal-where-is-it-found/ https://www.worldcoal.org/coal-facts/what-is-coal-where-is-i... Edit: Clarified availability.