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saict
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 Posted: Tue Nov 18, 2003 9:28 pm Post subject: Solar power from the moon, and now this.... |
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I>m not exactly sure how much advantage lunar He3 has over terrestrial
Deuterium, but this is food for thought regardless.
http://www.atimes.com/atimes/Global_Economy/EK15Dj01.html |
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G. R. L. Cowan
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| Posted: Tue Nov 18, 2003 10:07 pm Post subject: Re: Solar power from the moon, and now this.... |
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saict wrote:
[quote]
I>m not exactly sure how much advantage lunar He3 has over terrestrial
Deuterium, but this is food for thought regardless.
http://www.atimes.com/atimes/Global_Economy/EK15Dj01.html
[/quote]
The easiest fusion reactions to ignite are those
between two heavy hydrogen nuclei (both singly charged,
lowest possible Coulomb barrier).
If you can ignite reactions involving 3-He,
you can ignite fusion of 3-He and D (twice the Coulomb barrier)
or 3-He and itself (four times)
then you certainly can ignite D-D fusion,
and D-D fusion *produces* helium three.
The Moon will no doubt be put to use in new ways,
but providing helium-three will not be one of them.
--- Graham Cowan
http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.doc --
fireproof fuel, real-car range, no emissions |
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Cyril
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| Posted: Wed Nov 19, 2003 12:58 am Post subject: Re: Solar power from the moon, and now this.... |
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Retrouvons en direct thurberk@cscsw.com (saict), notre envoyé(e)
spécial(e) sur sci.energy.hydrogen:
[quote]I>m not exactly sure how much advantage lunar He3 has over terrestrial
Deuterium, but this is food for thought regardless.
[/quote]
No neutrons are made, resulting in a simpler energy conversion.
In D-D and D-T fusion, most of the energy is given to outgoing
neutrons (kinetic energy). They are not charged, so you can>t control
them using electrostatic or magnetic fields, so you must stop them
using metallic sjield that are heaten. Heat can then be converted
intpo electricity, like in your casual thermal plant.
With He3 you get no neutrons, but only charged particles. These
particles won>t exit the contained plasma, unless you ask them to do
so.
The plasma can be efficiencly converted into electricity using MHD
combined with more classcal thermodynamic conversion.
In MHD, the + and - particles from the plasma are separated using a
magnetic field and hit two electrodes.
(Sorry for approximative writing, english is a foeign language for me)
--
"Cette citation n>existe pas"
Beaumarchais, le coiffeur de Barcelone |
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saict
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| Posted: Wed Nov 19, 2003 6:12 am Post subject: Re: Solar power from the moon, and now this.... |
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"G. R. L. Cowan" <gcowan@eagle.ca> wrote in message news:<3FBA43B3.E7EA888B@eagle.ca>...
[quote]saict wrote:
I>m not exactly sure how much advantage lunar He3 has over terrestrial
Deuterium, but this is food for thought regardless.
http://www.atimes.com/atimes/Global_Economy/EK15Dj01.html
The easiest fusion reactions to ignite are those
between two heavy hydrogen nuclei (both singly charged,
lowest possible Coulomb barrier).
If you can ignite reactions involving 3-He,
you can ignite fusion of 3-He and D (twice the Coulomb barrier)
or 3-He and itself (four times)
then you certainly can ignite D-D fusion,
and D-D fusion *produces* helium three.
[/quote]
And neutrons.
[quote]The Moon will no doubt be put to use in new ways,
but providing helium-three will not be one of them.
[/quote]
The idea is to to do this one:
He3 + D => He4 + p + 18.4Mev
It>s cleaner in terms of stray neutrons, and as Cyril points out, the
proton can be used to produce electricity directly--a bit better than
a simple nuclear heater. The absence of so many stray neutrons means
the concrete walls (or whatever replaces them) don>t have to be as
thick.
This would be a 3 x Couloumb barrier scenario. Strictly from an
economic standpoint, the issue is whether the extra heat of ignition
compensates for the reduced thickness of the walls. I don>t think an
objective answer is possible until we build another shuttle and decide
on a material for the walls. |
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Cyril
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| Posted: Thu Nov 20, 2003 12:26 am Post subject: Re: Solar power from the moon, and now this.... |
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Retrouvons en direct thurberk@cscsw.com (saict), notre envoyé(e)
spécial(e) sur sci.energy.hydrogen:
[quote]It>s cleaner in terms of stray neutrons, and as Cyril points out, the
proton can be used to produce electricity directly--a bit better than
a simple nuclear heater. The absence of so many stray neutrons means
the concrete walls (or whatever replaces them) don>t have to be as
thick.
[/quote]
In fact, this is not critical for power plants. Weight (heavy shields
used to stop the neutrons) is not really an issue.
But space agancies hopes to build fusion-propelled interplanetary
spaceships (such ships will likely exist some day, but it is extremely
unlikely than any of us will see them :-((( ). For such an
application, weight is critical and getting rid of the shields would
be a must.
--
"Cette citation n>existe pas"
Beaumarchais, le coiffeur de Barcelone |
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