I have a question about fusion

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    Fusion
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Discussion Overview

The discussion revolves around the energy released during the fusion of deuterium and other isotopes of hydrogen. Participants explore various fusion reactions, their feasibility, and the calculations involved in determining the energy output. The scope includes theoretical aspects of fusion processes and calculations related to energy release.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions the energy release from the fusion of deuterium, presenting a simplified equation for hydrogen fusion.
  • Another participant argues that the fusion of two deuterium nuclei into helium is not feasible due to energy conservation issues, suggesting a more common fusion process involving deuterium and tritium.
  • A participant challenges the assertion that deuterium cannot fuse into an alpha particle, asking for clarification on the physical laws that would prevent this.
  • One participant calculates the energy released from the fusion of deuterium and tritium, arriving at a value of approximately 1.7 terajoules for one mole.
  • Another participant states that energy and momentum cannot be conserved in the fusion of deuterium nuclei into helium.
  • Further details are provided on alternative fusion reactions involving deuterium, including the energy outputs associated with each reaction.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of certain fusion reactions, particularly the fusion of deuterium into helium. There is no consensus on the validity of the proposed reactions or the calculations presented.

Contextual Notes

Some calculations depend on assumptions regarding the fusion processes and the conservation laws involved. The discussion includes unresolved mathematical steps and varying interpretations of the fusion reactions.

bill nye scienceguy!
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So here it is:

What is the energy released when one mole of deterium(?) undergoes complete fusion? Oh, here's the equation:

H + H = He

i don't know how to post but its 2,1 for both hydrogen isotopes and then 4,2 for the helium duh i know but i don't want confusion.

cheers ro><ors!


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Fusion can't go that way because there is nowhere for the energy to go.
The most common fusion process is
[itex]^2 H + ^3 H \rightarrow ^4 He + n.[/itex]
That is deutron + tritium --> helium + neutron.
If you want, I can calculate one mole of d on one mole of t.
 
U mean 2 nuclei of deuterium can't fuse into an alpha particle...? What laws of physics forbid that?

Daniel.
 
Billnye: The mass difference between d+t and He + n is 17.59 MeV.
Multiplying this by Avagadro's number (for one mole), and converting to Joules,
I get (Check my arithmetic.) 1.7 X 10^12 Joules released.
I guess that would be written as 1.7 tJ. That's more than I make in a year.
 
dextercioby: You can't conserve both energy and momentum in d+d--> He.
 
d + d --> 3He + n + 3.25 MeV (~50%)

d + d --> t + p + 4.0 MeV (~50%)
 

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