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Fusion Reactors

  1. Oct 18, 2004 #1
    How far is research really gone? Is there any major breakthrough on its way? Are the first prototypes ready yet?

    I'm making a project work on this for school, and I find it hard to find sufficient information in books and likes about this, since clearly, books from the beginning of the last decade are going to be very out-of-date today...

    I gathered from the Cold Fusion thread, that Cold Fusion is not even an option as it's not do-able?

    What are the major obstacles with a fusion reactor as of today? And are there any realistic plans to overcome these obstacles? How far is the research gone in the USA (this is also hard for me to find out since I'm situated in Sweden and mostly can gather info about the JET project)...

    ITER is a cooperative effort between Japan, USA and Europe, am I right?
  2. jcsd
  3. Oct 18, 2004 #2


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    First Cold Fusion was a fraud - a couple chemists went public with some
    work they didn't understand - and the physics community agrees that
    cold fusion never did exist.

    Controlled thermonuclear fusion is incredibily difficult - research has
    been underway for decades. There are two main approaches - magnetic
    confinement and inertial confinement.

    Magnetic confinement is the attempt to contain the reaction a magnetic
    "bottle". Tokamaks are the leading type of magnetic fusion machine.
    That said, the USA has not built a tokamak in years. The leading machine
    was the TFTR - Tokamak Fusion Test Reactor at Princeton University's
    Plasma Physics Center.

    The ITER would follow the work of TFTR - but it has been under discussion
    for over a decade - and nothing has actually been built.

    In the are of inertial confinemet fusion - i.e. "laser fusion" research is
    continuing at the Omega Laser at the University of Rochester. The NIF -
    the National Ignition Facility at Lawrence Livermore is in the process
    of bringing up the lasers. The physical facility has been built - and will
    eventually have 192 laser chains. About 8 laser chains are now operating:




    The NIF will be the first machine to achieve "ignition" - that is to
    generate as much energy from fusion as was put into the fusion fuel.

    However, that's a long, long way from generating large amounts of

    Dr. Gregory Greenman
    Physicist LLNL
  4. Oct 18, 2004 #3
    If you view ITERs website http://www.iter.org, somewhere on there is a timeline. I believe that they are expecting their experimental reactor to come online somewhere around 2010 so that commerically viable plants can be built later on.

    The United States dropped out of ITER for a while (political reasons) and rejoined last year along with China and Korea.
    Last edited: Oct 18, 2004
  5. Oct 18, 2004 #4


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    There are non-mainstream reactor designs. For example fusors (http://www.fusor.net/) which are not likely to ever produce net energy and sonoluminescent reactors (sorry, no link).
  6. Oct 19, 2004 #5
    I recently had the opportunity to visit Omega. The first major obstacle is to maintain the large temperature that is needed to make a reaction. With inertial confinement, it lasts for nanoseconds (a short laser pulse). A bit more (milliseconds?) is achieved with tokamaks. NIF will do an important step by reaching a break-even point.

    It is important to note that these systems are also used by astrophysicists to simulate star core physics, they are not just pre-pre-... - reactor prototypes.
  7. Oct 19, 2004 #6


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    I suppose the ITER project is lagging a bit due to the member countries bickering about the location of the next stage experimental reactor, which I think ought to be a major improvement over the previous ones and pave the way for "commercial" ones (with any luck).
  8. Oct 25, 2004 #7
    Fusion is too dangerous and has been killed. If you have a good fusion system you are able to transmute to produce any end product you wish. As you can guess that can be very dangerous.

    The best fusion results to date have been the predecessor of the proposed X-1 project


    This has dropped of the scope and I don’t think you will find anymore about results.
  9. Oct 25, 2004 #8
    Who said this and when? And what about fusion of iron and heavier atoms which are endothermic fusion reactions? In theory those elemnts could be fused but how would any man made machine be able to produce that much energy if even stars implode when fusing iron?
  10. Oct 25, 2004 #9


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    The only practical fusion reactors are those converting isotopes of hydrogen to helium. Anything else would involve much higher temperatures and pressures and would be impossible today on any useful scale.
  11. Oct 25, 2004 #10
    Exactly, mathman. Being able to produce any end product you could want would require being able to do H to He and get net energy from it, to continue fusion. Producing Plutonium or Uranium from just Hydrogen would still be a long ways off even if we could.
  12. Nov 2, 2004 #11


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    Exactly - producing Plutonium and Uranium is best left to supernovae.

    You get the minimum binding energy per nucleon with Iron.

    If you fuse elements lighter than Iron - you get energy.

    If you fission elements heavier than Iron - you get energy.

    Dr. Gregory Greenman
  13. Nov 29, 2004 #12
    I'm hedging my bets on saltwater. Hot fusion seems to be our only road forward. I'm still undecided as to whether I should study magnetic confinement or inertial/laser systems though. My gut says "magnetics", but laser-type systems have become more viable. Is this correct? This is my first year in college, and I do have to choose a suitable university in Ca.
  14. Nov 29, 2004 #13


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    Savitri, the University of California has very good engineering programs at the San Diego (UCSD), Santa Barbara (UCSB) and LA (UCLA) campuses. And there is also UC Berkeley, which still has a nuclear engineering program.

    In addition, General Atomic is located there in San Diego.
  15. Nov 30, 2004 #14
    Thanks Astronuc.
  16. Nov 30, 2004 #15
    Ok, this thread is a bit old (has been dormant for about a month until yesterday), but if anyone is still interested, goolge for "fusion ignition research experiment", aka FIRE (unforetunately, googling for "fire" gives too many irrelevant results, so you have to use the full name).
  17. Dec 3, 2004 #16


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    Heard today that the location of ITER might finally be set ... France ... I've been out of the loop for a while, anyone got any other information on this or is this just a scoop ?
  18. Nov 27, 2005 #17
    What happens if you replace the NIF lasers with say electrons with the proper energy to create x-rays in a closed high-Z chamber?

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