Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Helium 3 fusion reactor?

  1. Jan 24, 2016 #1
    I have this project in school for settlement on moon. I have this idea that the large quantities of He 3 on moon could be extracted by heating the regolith at 700 degrees celsius and then could be taken to a reactor in which He 3 could be fused with Deuterium or itself. The heat produced could be harnessed by heat shields and then taken to a turbine for converting to electricity. Could this reactor work ? I read about this process online and i want someone to elaborate it for me .
    Thanks for going through my question !
     
  2. jcsd
  3. Jan 24, 2016 #2
    There's still the teeny-tiny difficulty of achieving a controlled fusion reaction.
     
  4. Jan 26, 2016 #3
    Yes, this is plausible. There are several people who are promoting mining the moon for He-3 to both power a lunar colony and to use as a power source for further space exploration. Fusion is a attractive fuel for space exploration because it is very energy dense. Also as you probably know it is very expensive to launch anything into space from Earth. It costs about $10,000 to launch 1 pound into space. The moons gravity in much weaker than Earth's. After we establish a lunar colony, it will be much cheeper to launch fuel into space from the moon than from Earth. (Of course establishing a lunar colony will not be cheep).

    I know one proponent of this idea is Harrison Schmitt. He was an astronaut on Apollo 17, and as a geologist he is the only scientist who walked on the moon. He taught a course on resources from space at the university of Wisconsin a while ago, and the lecture notes were publicly available. Unfortunately, the website is down right now. But with a little bit of google-fu you might be able to find them backed up somewhere.


    Of course as others are quick to point out fusion isn't ready yet, but then again we're not colonizing the moon either. Both are challenging problems. Don't let that stop you.
     
  5. Jan 26, 2016 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    3He + D releases 18 MeV of energy. Lunar regolith concentrations of 3He are up to 80 ppb, or 1.4 eV per atom of regolith processed. Heating material to 700 degrees needs about 0.1 eV per atom, but you can gain back some part of it with a clever heat exchange design. It is possible, but the margin is not so large. Your fusion reactor should be highly efficient. Using pure helium fusion reduces the energy gain to 6.5 MeV per atom of 3He, nearly a factor 3 worse. On the positive side, it would avoid DD fusion as side-reaction, this reaction leads to neutron activation of the reactor walls.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Helium 3 fusion reactor?
  1. Fusion Reactors (Replies: 16)

Loading...