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The False Promise of Nuclear Fusion?

  1. Jan 3, 2016 #1
    I would like to share this recent article by Linda Gunter:

    http://www.counterpunch.org/2015/12/11/the-false-promise-of-nuclear-fusion/


    Are renewables really the future of an increasingly energy hungry human civilization, as mentioned by Linda?

    Or can we use HITACHI's PRISM reactors to solve the problem of nuclear waste?

    Is fusion centuries, not decades, away?
     
    Last edited: Jan 3, 2016
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  3. Jan 3, 2016 #2

    mfb

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    It is hard to write an article even more manipulatively.
     
  4. Jan 3, 2016 #3

    Choppy

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    I think a lot depends on the amount people want to invest in the problem. If it was a major priority, I think it could be cracked a lot sooner. But it seems to me that fusion research is dogged by vocal anti-nuclear groups that drag it down. On top of that, it requires substantial and sustainable investment - which is difficult to come by when governments feel a constriction of their budgets and need to look for places to cut.

    Contrary to the article, I think that talk of fusion reactors is precisely what needs to be happening at climate change conferences.
     
  5. Jan 4, 2016 #4
    Good chance that both inertial confinement and magnetic containment are impractical. Tokamaks like ITER are said to be unstable and its said they will have ruinous plasma disruptions within seconds of first producing power. Stellarators haven't demonstrated good containment yet.
     
  6. Jan 4, 2016 #5

    russ_watters

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    Yes. While the main point that fusion has thus far been fools-gold and even if it works will be too late to fix this century's global warming, it is hard to argue that a large first-world country couldn't go all fission while discussing a climate forum that took place in a large first-world country that went all fission many decades ago.

    And thus far, the trendy renewables have also been a bust.
     
  7. Jan 5, 2016 #6
    The article was written quite recently though.
     
  8. Jan 5, 2016 #7
    Do you guys think we can build practical fusion generators within the next few decades?
     
  9. Jan 5, 2016 #8
    Well we'll have to wait 10 years to find out.
     
  10. Jan 5, 2016 #9

    russ_watters

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    Yes....but what is your point?
    Even if the next one works, we're probably at least 40 years away from the first commercial fusion power plant.
     
  11. Jan 5, 2016 #10

    mfb

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    I would be extremely surprised if a commercial fusion power plant opens before 2050, but that is not the point.
    I would also be extremely surprised if there are no coal power plants operating in 2050.
     
  12. Jan 6, 2016 #11
    The problem is even fusion reactors will provide power based on steam technology from the 19th century. They will use the heat from the fusion process to make steam to turn turbines to generate electricity. It may be possible to generate electricity directly from the plasma stream using some sort of Magneto-Hydrodynamic Principles, but I have not heard of anyone developing generation of electricity in this way.
     
  13. Jan 6, 2016 #12

    mfb

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    Bread, wine, beer and various other products are made based on concepts thousands of years old. Should we stop making them now?

    DT fusion, which is by far the easiest fusion process, releases most of the energy as neutrons. There is no electromagnetic way to capture this energy.

    A direct conversion of fast charged particles to electricity can improve the efficiency, yes - but you gain at most a factor of ~2, while you lose a factor of 10 to N orders of magnitude in fusion power density.
     
  14. Jan 6, 2016 #13
    Why is this a problem? Fusion is hard enough as it is. Where possible we should make use of the best technologies perform a specific task. Right now modern day thermodynamic cycles are the best technology for converting large amounts of thermal energy into electricity. Also calling modern day these technologies 19th century ignores the many significant advances that have been made in the past century.

    For the record there is research into developing direct energy conversion technologies. But progress is slow, and these technologies simply don't yet compete. And as mfb pointed out for D-T fusion there is still the problem of caputering the energy carried by the neutrons.

    Don't let some idealistic prejudice prevent us from the right tool for the job.
     
  15. Jan 6, 2016 #14
    The fast neutrons released by fusion destabilize the nuclei with which they collide. Radioactive waste is produced.

    My Dad was a consultant to the first company to induce fusion with a laser. He showed me the rig once.
     
  16. Jan 7, 2016 #15

    mfb

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    It depends on the isotopes the neutrons interact with. Pure aluminium for example doesn't get activated much, while silver and steel are problematic.
     
  17. Jan 9, 2016 #16
    meaning that the author currently has faith in the trendy renewables you say are a bust
     
    Last edited: Jan 9, 2016
  18. Jan 9, 2016 #17

    Astronuc

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    Generally, designers want an alloy with high melting point, and creep resistance, as well as low activation potential.

    Al has low melting temperature so is not useful for power generation. V and W-184, also have relatively low activation cross-sections, but high melting temperature.

    Fe-Cr-Al, Fe-W-V alloys are of interest in some applications.

    Ideally, one would develop some direct conversion system, possible with some thermal conversion system, using predominantly aneutronic fusion reactions. So far, power generation systems with even the easiest reactions like d+t have proven elusive.
     
  19. Jan 15, 2016 #18
    Have they looked at creating a fusion breeder using a blanket of Li-6? That would protect the reactor from neutron damage and produce more fuel.

    Also, looking at Gunter's other articles... she just spews tripe.
     
  20. Jan 15, 2016 #19
    Yes, in fact i is necessary for a D-T fusion reactor to have a lithium blanket. Tritium does not occur naturally. A D-T fusion reactor will have to breed tritium at the same rate that it burns tritium. Producing a excess of tritium is a concern due to proliferation, and we will quickly run out of tritium if we produce too little. We should be able to fine tune the tritium breeding ratio by adjusting the ratio of Li-6 and Li-7. However, neutron damage is a huge concern even with a blanket.
     
  21. Jan 15, 2016 #20
    Anyone who can breed Pu-239 can make tritium. It's really not a proliferation concern.
     
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