Re: Fusion Reactors

From: Iain Strachan (iain.g.d.strachan@ntlworld.com)
Date: Sun Sep 08 2002 - 06:48:30 EDT

  • Next message: george murphy: "Re: Fusion Reactors"

    Hi, George,

    You wrote:

    Of course we can build a fusion reactor.=20
              But there is no guarantee that this is possible. Of course =
    controlled=20
    fusion is possible - the sun does it all the time. But short of building =
    a=20
    star, it may be that plasma instabilities and all the other problems =
    that=20
    beset controlled fusion research will mean that fusion as a source of =
    power=20
    for everyday use just isn't viable.=20

    I think this is perhaps too pessimistic. I'm sure most physicists =
    working on Fusion really believe that it is possible; we are not relying =
    on developing "warp drives" or other as yet unknown bits of physics to =
    solve the technology problems. It is just that they will take far more =
    time than we appear to have, if Glenn is correct about oil running out.

    As it happens, I spoke to a plasma physicist who works on the JET =
    experiment this morning after church. This is what happens next in the =
    programme.

    (1) The next big experiment is called ETA, and its purpose will be to =
    demonstrate continuous generation of power by controlled nuclear fusion. =
      However, there will be no attempt to convert this power into =
    electricity. The purpose of the experiment is largely to determine the =
    correct plasma parameters for a fusion reactor. The plasma =
    instabilities are not an insurmountable problem, but one does need to =
    build very large experiments costing billions, in order to get them =
    right. At present, several sites in Europe, Japan and Canada are being =
    considered and assessed for feasibility for building the experiment. =
    Countries involved are Russia, Europe, Japan, Canada. Not America at =
    present. Once the site is agreed on, it will take 12 years to build the =
    experiment and get plasmas into it, and a further 12 for the =
    experimental programme.

    (2) The reusults from ETA are then supposed to feed into DEMO, a =
    demonstration Fusion power station, which will supply electricity to the =
    grid. This will also take 12 years to build and 12 to run. By which =
    time the feasibility will have been established.

    Hence the current estimate for when we get fusion in practice is 2050. =
    I asked about Glenn's suggested 20 year time span. The response was as =
    I expected; no-one working in Fusion research would consider 20 years =
    as anything other than a "pipe-dream" (his words). Throwing extra =
    money at it might reduce the timescales somewhat, but would never reduce =
    it by anything like a half.

    I also asked about the other technology problems that had to be solved. =
    He was of the opinion that the Tritium breeding was not the most =
    difficult problem (though still hard). There will be a lithium blanket =
    in the ETA experiment. In his opinion the hardest problem was the =
    design of the materials for the vacuum vessel. (To withstand corrosion, =
    radiation, etc).

    I can add here that I started my career at the UKAEA Culham labs =
    particularly because I believed that Fusion was the future solution to =
    our energy needs. That was in 1981. The very day I joined, the =
    Conservative government axed the large experiment I was recruited to =
    work on (RFX), which eventually got built on a reduced scale in Italy. =
    The government continued its destructive course by turning the UKAEA =
    into a Trading Fund, where we were obliged to make money by exploiting =
    some of the technology that had been developed in the fusion programme. =
    For example, much laser technology had been developed for plasma =
    diagnostics (measuring the plasma temperature by Thompson scattering). =
    The laser expertise we had developed was then diverted into more =
    immediately lucrative projects, such as developing a machine for cutting =
    a pattern in the security thread for the 50 pound note. That's what =
    governments do to long term programmes that won't get them any votes =
    when they come to get re-elected. Needless to say this is all pretty =
    depressing, but it has to be said that the naive idealism with which I =
    started my career has been replaced by a more realistic, if less hopeful =
    attitude.

    So it would appear to me that if its true that we're all going back to =
    the middle ages if we don't get Fusion power stations being churned out =
    by the dozen in 20 years, then that is precisely what will happen, and =
    we'd better get used to the idea.

    Iain.



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