From: george murphy (gmurphy@raex.com)
Date: Sun Sep 08 2002 - 07:11:13 EDT
Iain Strachan wrote:
> Hi, George, You wrote: Of course we can build a fusion reactor.
> But there is no guarantee that this is possible. Of course
> controlled
> fusion is possible - the sun does it all the time. But short of
> building a
> star, it may be that plasma instabilities and all the other problems
> that
> beset controlled fusion research will mean that fusion as a source of
> power
> for everyday use just isn't viable. 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.
Let me clarify. I was not saying controlled fusion _is_
impossible, that it's in the same category as interstellar travel, or
that there should not be intensive work on it. My point was simply that
a technology is not necessarily achievable just because we need it in
order to maintain a certain standard of living. & I'd add that the
technological optimism I referred to can be self-deluding & dangerous if
it enables people to say that we don't need to be concerned about
reducing petroleum use &c because fusion energy will be available when
we need it.
Shalom,
George
George L. Murphy
http://web.raex.com/~gmurphy/
"The Science-Theology Interface"
This archive was generated by hypermail 2.1.4 : Sun Sep 08 2002 - 15:28:11 EDT