What do Netpeople think about fusion?
Robert F. Heeter
got some ideas on the subject. Some of us here were wondering how
everyone else out there perceives fusion as a potential future energy
source. My perception is that the only long-term, large-scale,
environmentally
friendly energy sources are solar (thermal or photovoltaic) and fusion
(magnetically or inertially confined). I see fusion (and hydro) for
baseload,
and solar (possibly combined with energy storage) for peak demand.
This isn't going to happen anytime soon, maybe not within any of our
lifetimes, but is there any other way we can go? What do people think?
******************************************************************
* Robert F. Heeter #include PithyQuotation.h *
* rfhe...@tom.pppl.gov #include StdDisclaimer.h *
******************************************************************
Silent Dreamer
[ Can we use fusion as a long-term power alternative? ]
In my opinion, it doesn't seem practical for the future for one simple
reason---we have a hard time getting ahold of hydrogen, let alone the problems
with storing it. Also, what form would the energy be released as? Hard
radiation is NOT an easy form of energy to extract (to my knowledge, which is
admittedly fairly limited).
--
Quote: "Love may conquer everything, but it needs Time as its Field General."
Let darkness disappear/In the rays of sunshine/That come from within my heart/
Whenever I think of you.
Dick Lynch
Robert F. Heeter <rfhe...@lyman.pppl.gov> wrote:
>As a graduate student in plasma physics here at Princeton, I've obviously
>got some ideas on the subject. Some of us here were wondering how
>everyone else out there perceives fusion as a potential future energy
>source. My perception is that the only long-term, large-scale,
>environmentally
>friendly energy sources are solar (thermal or photovoltaic) and fusion
>(magnetically or inertially confined). I see fusion (and hydro) for
>baseload,
>and solar (possibly combined with energy storage) for peak demand.
>This isn't going to happen anytime soon, maybe not within any of our
>lifetimes, but is there any other way we can go? What do people think?
>
>* rfhe...@tom.pppl.gov #include StdDisclaimer.h *
You are probably aware of the USENET group sci.physics.fusion , where
you'll probably get a broader range of opinions than here. (Well, maybe
a larger number, anyway.)
I don't agree that hydro power will be used for baseload in the future.
Except for only a few special instances, it is not being used that way
now; it's used for peaking. There just isn't enough hydro available to
justify baseload use (except in very rainy seasons, where the water would
otherwise have to be gated through the dams.) TVA, one of the major hydro
generators in the nation, still uses nuclear and coal-fueled plants for
baseload. Ideally for baseload, you'd want a large facility that has the
economy of scale working for it, and that's nuclear (and large fossil).
Hydro, by it's very nature, is easy-on, easy-off -- ideal for peaking.
Dick Lynch; ly...@access.digex.net
John De Armond
>As a graduate student in plasma physics here at Princeton, I've obviously
>got some ideas on the subject. Some of us here were wondering how
>everyone else out there perceives fusion as a potential future energy
>source.
Having heard "breakeven just around the corner" for the last 30 years
or so, I've come to regard fusion research as the world's second
largest welfare program for scientists, right behind NASA. Second only
because NASA can spend it faster.
My perception is that the only long-term, large-scale,
>environmentally
>friendly energy sources are solar (thermal or photovoltaic) and fusion
>(magnetically or inertially confined). I see fusion (and hydro) for
>baseload,
>and solar (possibly combined with energy storage) for peak demand.
>This isn't going to happen anytime soon, maybe not within any of our
>lifetimes, but is there any other way we can go? What do people think?
Projecting out more than about 50 years is very risky. Reading some of
the scientific predictions of the previous century is pretty
entertaining. Fortunately for that generation, however, there wasn't a
government foolish enough to act on them.
No reason why conventional fission in some breeding cycle or the other
can't supply the bulk of our needs long enough into the future
so as to be essentially man-infinity. Apparently at least Georgia
Power sees it that way too. The Prez of the utility spoke this week at
a civic club meeting in Marietta. He said he expects Ga power to
be generating the bulk of their power with nuclear into the next century.
Since Ga Pwr now generates only about 20% nuclear, that implies a
significant construction program in the not too distant future.
He demurred when ask about plans for the next reactor.
John
--
John De Armond, WD4OQC | For a free sample magazine, send
Performance Engineering Magazine(TM) | a digest-size 52 cent SASE
Marietta, Ga "Hotrods'n'computers" | (Domestic) to PO Box 669728
j...@dixie.com "What could be better?" | Marietta, GA 30066
Any mail to me may be published at my sole discretion.
Greg Stewart-Nicholls
>As a graduate student in plasma physics here at Princeton, I've obviously
>got some ideas on the subject. Some of us here were wondering how
>everyone else out there perceives fusion as a potential future energy
>source. My perception is that the only long-term, large-scale,
>environmentally
>friendly energy sources are solar (thermal or photovoltaic) and fusion
>(magnetically or inertially confined). I see fusion (and hydro) for
>baseload,
>and solar (possibly combined with energy storage) for peak demand.
>This isn't going to happen anytime soon, maybe not within any of our
>lifetimes, but is there any other way we can go? What do people think?
fusion (power from seawater) isn't likely to be viable for a couple
of centuries (barring _major_ breakthroughs), current efforts involve
Lithium and Tritium, and would have similar management requirements as
fission does.
If your definition of 'environmentally friendly' includes the cost
of production as well as land use, maintenance etc, then you can get
a different picture than if you just take waste products into account.
-----------------------------------------------------------------
Greg Nicholls ... : Vidi
ni...@vnet.ibm.com or : Vici
ni...@olympus.demon.co.uk : Veni
T Orth FP/207/ 8505
Hard radiation? Hmmm, don't quite know what you mean. In any event, the
radiation would deposit most of its energy in something like a blanket
surrounding the reactor. It could be made up of water for producing heavy
water and tritium from the neutrons produced.
Theoretically, the cost of etting the hydrogen from water through electrolyses
would be minimul compared to the energy released from fusion.
Energy is almost always released as radiation in almost any process. After
the energy has been released and absorbed by something else, it can then
convect/conduct.
Tom Orth
Nuclear Engineer
Argonne National Laboratory
Speaking for myself
or...@flicker.fp.anl.gov
Brian Jones
:Robert F. Heeter <rfhe...@lyman.pppl.gov> writes:
:
:[ Can we use fusion as a long-term power alternative? ]
:
: In my opinion, it doesn't seem practical for the future for one simple
:reason---we have a hard time getting ahold of hydrogen, let alone the problems
What planet are you from?
Earth has plenty of hydrogen.
:with storing it. Also, what form would the energy be released as? Hard
:radiation is NOT an easy form of energy to extract (to my knowledge, which is
:admittedly fairly limited).
A working fusion plant will probably use direct conversion to
electricity. since fusion produce way less radiation than fission, and
we have working fission plants, I think we can handle it.
--
|------------------------ "History shows again and ------------------------|
| DISCLAIM again how nature points Brian R. Jones |
| THIS! out the folly of men" bjo...@vsattui.llnl.gov |
|------------------------ B.O.C. ------------------------|
Mark O. Wilson
|Robert F. Heeter <rfhe...@lyman.pppl.gov> writes:
|[ Can we use fusion as a long-term power alternative? ]
| In my opinion, it doesn't seem practical for the future for one simple
|reason---we have a hard time getting ahold of hydrogen, let alone the problems
|with storing it. Also, what form would the energy be released as? Hard
|radiation is NOT an easy form of energy to extract (to my knowledge, which is
|admittedly fairly limited).
What makes you think that the major energy from fusion is in the form of
hard radiation?
BTW, hydrogen is not hard to get hold of it, nor do we have problems
storing it.
--
Mob rule isn't any prettier merely because the mob calls itself a government
It ain't charity if you are using someone else's money.
Wilson's theory of relativity: If you go back far enough, we're all related.
Mark....@AtlantaGA.NCR.com
Mike Van Pelt
>This isn't going to happen anytime soon, maybe not within any of our
>lifetimes, but is there any other way we can go? What do people think?
Fusion has been "Real Soon Now" for so long that I've given up
waiting for it.
Some statements I see here are addressed to specific fusion
technologies, and are not applicable to others. For instance,
comments about the problems of high neutron flux are not applicable
to aneutronic fusion, like 3He. (Yes, it's harder to fuse 3He than
other fuels, but since all products are charged particles, you can
do direct conversion to electricity.)
My strongest conviction about fusion is that I am absolutely certain
that if and when fusion becomes a practical source of cheap, clean,
abundant energy, All The Usual Suspects are going to be all over it
with "Fusion Kills" signs, chaining themselves to the gates, and
locking it up in the courts. Did you see Paul Erlich's editorial back
when it looked like Cold Fusion was for real? He denounced it as
a disaster for the environment, sight unseen.
--
Mike Van Pelt | What happens if a big asteroid hits Earth?
m...@netcom.com | Judging from realistic simulations involving a
| sledge hammer and a common laboratory frog, we
| can assume it will be pretty bad. -- Dave Barry
Craig Powderkeg DeForest
A working fusion plant will probably use direct conversion to
electricity. since fusion produce way less radiation than fission, and
we have working fission plants, I think we can handle it.
Actually, this (the idea that fusion will be a nice, clean energy
source) is a popular misconception. The most likely plasma hot-fusion
scenario is tritium-tritium or at least tritium-deuterium fusion, both
of which produce scads of neutrons and lots of messy neutron-
activation products, not to mention that they use tritium, which is a
pretty hazardous radioisotope (hard to contain, and it *loves* to get
into people, who are perhaps 1/3 hydrogen by nucleus count).
--
DON'T DRINK SOAP! DILUTE DILUTE! OK!
Jonathan Burns
>
> Having heard "breakeven just around the corner" for the last 30 years
> or so, I've come to regard fusion research as the world's second
> largest welfare program for scientists, right behind NASA. Second only
> because NASA can spend it faster.
There was a paper a few years back which argued for a fusion-fission
cycle. The fusion reaction was not to generate net power, but neutrons
for enrichment of U238.
I never could decide whether an independent neutron source would
have advantages over a fission breeder. Suppose we could make this
machine which efficiently converts electricity and lithium into
neutrons. Would that make for a more tractable design?
Jonathan
Jonathan Burns
> As a graduate student in plasma physics here at Princeton, I've
obviously
> got some ideas on the subject. Some of us here were wondering how
> everyone else out there perceives fusion as a potential future energy
> source. My perception is that the only long-term, large-scale,
> environmentally
> friendly energy sources are solar (thermal or photovoltaic) and fusion
> (magnetically or inertially confined). I see fusion (and hydro) for
> baseload,
> and solar (possibly combined with energy storage) for peak demand.
> This isn't going to happen anytime soon, maybe not within any of our
> lifetimes, but is there any other way we can go? What do people think?
Well, the articles we read say hopefully that in time we can build
a massive tokamak which mostly puts out high-energy neutrons,
accumulates neutron damage and radioisotope buildup in all members,
has to manage a modest tritium inventory - and at the end it's
_still_ thermal->electric, and needs big ponds to cool it. It's
a lot of money to spend on just that, when we could breed plutonium
indefinitely at the cost of stringent safety and waste management.
I'm a bit heretical, though. Having been reading IEEE Trans. Plamsa
lately, I see the number of ways in which RF energy, microwaves,
lasers, magnetic flux, plasmas and electron beams can be interconverted
is growing amazingly. Most of these conversion mechanisms are low
efficiency, but the plasma engineering field is opening up.
Maybe - just maybe - there's a path to the flux*density*duration
products we want for D-T, even D-D. There seems to be room for
radical ideas. It's an enviable time to be a graduate student in
plasma physics.
Jonathan
James King
[stuff deleted]
>My strongest conviction about fusion is that I am absolutely certain
>that if and when fusion becomes a practical source of cheap, clean,
>abundant energy, All The Usual Suspects are going to be all over it
>with "Fusion Kills" signs, chaining themselves to the gates, and
>locking it up in the courts. Did you see Paul Erlich's editorial back
>when it looked like Cold Fusion was for real? He denounced it as
>a disaster for the environment, sight unseen.
>
Well, what did you expect from Erlich; that's his line of work. :-(
--
Jim
#include <disclaimers.h>
T Orth FP/207/ 8505
|>
|> Some statements I see here are addressed to specific fusion
|> comments about the problems of high neutron flux are not applicable
|> to aneutronic fusion, like 3He. (Yes, it's harder to fuse 3He than
|> other fuels, but since all products are charged particles, you can
|> do direct conversion to electricity.)
HUH????? The reason that fusion is even considered worthwhile for generating
electricity is because it releases HUGE amounts of energy. This energy is
in the form of kinetic energy of particles (gamma and charged). This HEAT
would be used in a heat engine...probably Rankine steam cycle of some kind.
The notion that the charged particles resulting could generate electricity with
the ions in the plasma is well....I just don't know what to say...ridiculous
I guess.
|
|> --
|> Mike Van Pelt | What happens if a big asteroid hits Earth?
|> m...@netcom.com | Judging from realistic simulations involving a
|> | sledge hammer and a common laboratory frog, we
|> | can assume it will be pretty bad. -- Dave Barry
Tom Orth
Nuclear Engineer
Argonne National Laboratory
Speaking for myself
Bruce Scott
>A working fusion plant will probably use direct conversion to
>electricity. since fusion produce way less radiation than fission, and
>we have working fission plants, I think we can handle it.
This is unlikely in any of the usual fusion scenarios. The "ideal"
reaction from the supply point of view is
D + D --> He3 + n
--> T + p
with about a 50 percent branching ratio. Then the secondary reactions
D + He3 --> alpha + p
D + T --> alpha + n
produce most of the energy. In the first D + D reaction, only about 4
MeV per reaction is produced. In an extended plasma, the neutrons are
most likely lost, dumping its energy into a thermal blanket. The
charged particles participate in collisions (which are really
long-range encounters) and are confined by the magnetic field, so they
hopefully dump their energy into the plasma. In the secondary
reactions, the same considerations apply, with that 14 MeV neutron
from D + T dumping its energy into your thermal blanket just like in
the present-day DT fusion scenario.
The other scenario which gets talked about is the fission-fusion
hybrid, which I won't discuss any further than to point out that it
obviously also deals with neutronic waste and a thermal blanket.
The only possibility of direct-conversion, neutron-free fusion is to
make use of the reaction
p + B11 --> 3 alpha + 8.7 MeV
and have the alphas *not* dump their energy into the plasma but into
some sort of electric conversion device. Not physically impossible,
but not something I could easily imagine. A magnetised plasma able to
confine the original p and B particles would also most likely eat the
alphas as well.
So, the likelihood of a fusion device free of heat cycle limitations
is not obvious from today's standpoint.
By the way, the reason we all work with DT rather than DD today is
that the cross section for DT, while not so much larger than that for
DD, peaks at much lower energy, mininising the temperature at which
the plasma must be held. This is not an end scenario, hopefully.
"Plentiful" power would only come from straight deuterium fuel.
--
Gruss,
Dr Bruce Scott The deadliest bullshit is
Max-Planck-Institut fuer Plasmaphysik odorless and transparent
b...@hagar.ph.utexas.edu (to 12 Oct) -- W Gibson
Paul Dietz
>|> to aneutronic fusion, like 3He. (Yes, it's harder to fuse 3He than
>|> other fuels, but since all products are charged particles, you can
>|> do direct conversion to electricity.)
> HUH????? The reason that fusion is even considered worthwhile for
> generating electricity is because it releases HUGE amounts of energy.
> This energy is in the form of kinetic energy of particles (gamma and
> charged). This HEAT would be used in a heat engine...probably
> Rankine steam cycle of some kind. The notion that the charged
> particles resulting could generate electricity with the ions in the
> plasma is well....I just don't know what to say...ridiculous I guess.
Clearly you are not that familiar with fusion research, Tom. Folks
have been looking at "direct conversion" for years. There are many
ways it might be done. It is not appropriate for dt fusion, where 80%
of the energy comes out in the neutrons, but it would be useful for
dd, d3He, or more advanced forms.
Fusion itself typically liberates almost no energy in gammas, btw.
Paul F. Dietz
di...@cs.rochester.edu
Bruce Scott
>Fusion has been "Real Soon Now" for so long that I've given up
>waiting for it.
In this we are still paying for the enthusiasm of people who in the
1950s paid no attention to the emerging science of turbulence, and
thought that the production of an MHD-stable magnetic plasma
confinement device would be sufficient to make fusion. You see, if
thermal and particle transport were really caused solely by
collisional diffusion, we would have been producing fusion for the
last 20 years or so.
Unfortunately, it is not like that. Small fluctuations in density or
temperature cause small electric field fluctuations, since the
electrons (with their smaller mass) tend to run away (along magnetic
field lines) from a compression much faster than the ions. Since the
processes are rather slow, the small electric fields generated by this
incipient separation hold the electrons back so that the electron and
ion densities are held equal up to a small correction. These electric
field fluctuations, however, give rise to small-eddy bulk drifting
*across* the magnetic field lines. Turbulence between these "E cross
B" eddies and the density and temperature fluctuations give rise to a
bulk transport out of the device at a rate which is much larger than
would obtain from collisional diffusion, particularly at high
temperatures.
Nobody even surmised this back in the 1950s when all the boy-wonder
propaganda was generated, and people have regrettably taken to
ass-covering rather than truth-telling. It continues today, when
worries over the ability of industrial materials to withstand the sort
of power loads they are going to get in a reactor are not discussed
outside our community. This is a mistake, in my opinion. But
scientists are not to blame for this, unless they submerge their
careful skepticism and make common cause with the Government
propaganda machine. Unfortunately, most of the encounters of the
general public with scientists are with this second sort, and a very
jaundiced and unjustified opinion of scientists in general on the part
of the general public results. Hence, all these "real soon now"
comments and the (predictable) reaction to them. Unfortunately, when
people like me tell the truth about theoretical confinement study ("I
can identify a physical process which I know is important from
comparisons to experimental observations, but because of the necessary
simplifications it is premature to discuss scaling laws, from this
theoretical model or any other.") we get brushed aside or ignored,
because there are any number of people who will beat their chests
("This code has *everything*." or "That issue is *settled*.") to get
attention and, yes, increased funding.
>Some statements I see here are addressed to specific fusion
>technologies, and are not applicable to others. For instance,
>comments about the problems of high neutron flux are not applicable
>to aneutronic fusion, like 3He. (Yes, it's harder to fuse 3He than
>other fuels, but since all products are charged particles, you can
>do direct conversion to electricity.)
This is unlikely. I assume you are discussing the reaction
He3 + D --> alpha + p + 18.3 MeV
Unfortunately, you will get a number of secondary reactions
D + D --> He3 + n
--> T + p (50 percent branching ratio)
from which you will get some
D + T --> alpha + n
with that big, bad 14 MeV neutron. For aneutronic fusion you need
p + B11 --> 3 alpha
but B11 is exotic fuel and the cross section may be difficult
(unfortunately, the NRP Plasma Formulary does not tabulate it).
>My strongest conviction about fusion is that I am absolutely certain
>that if and when fusion becomes a practical source of cheap, clean,
>abundant energy, All The Usual Suspects are going to be all over it
>with "Fusion Kills" signs, chaining themselves to the gates, and
>locking it up in the courts. Did you see Paul Erlich's editorial back
>when it looked like Cold Fusion was for real? He denounced it as
>a disaster for the environment, sight unseen.
I'll worry about this when the time comes. Population-growth-induced
environmental problems will be all over us before fusion power comes
on line. Obviously, all those brilliant statements at last year's IAEA
meeting about how fusion is the hope of all those Third-World masses
who want Western-level energy consumption are pretty laughable.
Bruce Scott
>Actually, this (the idea that fusion will be a nice, clean energy
>source) is a popular misconception. The most likely plasma hot-fusion
>scenario is tritium-tritium or at least tritium-deuterium fusion, both
>of which produce scads of neutrons and lots of messy neutron-
>activation products, not to mention that they use tritium, which is a
>pretty hazardous radioisotope (hard to contain, and it *loves* to get
>into people, who are perhaps 1/3 hydrogen by nucleus count).
I think you mean "deuterium-deuterium or at least tritium-deuterium"
here. There is no energy gain from a T + T reaction. Your other
comments are correct, not least because in any credible scenario
(except p + B11, a big maybe) there will always be the reaction
D + T --> alpha + n
with the 14 MeV neutron, at least as a secondary reaction.
In addition to tritium, some pretty exotic things have to be done to a
plasma containment vessel to keep the plasma at least reasonably free
of impurities (which pick up energy by excitation from collisions with
the electrons and radiate it away), and this involves toxic stuff.
(Whether it is the boron or what is used to apply the boron to the
vessel, I don't know.)
Moreover, we have to come up with a material or combination of
materials out of which to make the "divertor target plates" which have
to take up all the energy which comes out of the plasma. That involves
an industrial process which is probably not too clean, and plenty of
toxic materials.
Of course, other power scenarios have similar problems, but this is
just to counter all those "cheap, clean, limitless" statements.
T Orth FP/207/ 8505
Let's get a sustained reaction first eh? I'm not saying that it would
be impossible to do direct conversion..ridiculous maybe..but not impossible.
However, if you can demonstrate to me how or why you can do dd when we
can't even do dt well...then I withdraw my statement.
Paul Dietz
> Let's get a sustained reaction first eh? I'm not saying that it would
> be impossible to do direct conversion..ridiculous maybe..but not impossible.
> However, if you can demonstrate to me how or why you can do dd when we
> can't even do dt well...then I withdraw my statement.
Actually, the most likely replacement would be d3He, not dd. 3He
would have to mined in space if this were to be done on a large scale,
granted.
The reason we should think about it is that the kind of reactor
appropriate to dt may not be appropriate to advanced fuels, and that
fusion may be pointless without advanced fuels. We can boil water
just fine with fission, and the turbines in a fusion plant aren't
going to be vastly cheaper.
Anyway, I don't see the justification for the "ridiculous" epithet.
Paul F. Dietz
di...@cs.rochester.edu
P Angelo /RA/208G/osra 7550
>
>Projecting out more than about 50 years is very risky. Reading some of
>the scientific predictions of the previous century is pretty
>entertaining. Fortunately for that generation, however, there wasn't a
>government foolish enough to act on them.
>
>No reason why conventional fission in some breeding cycle or the other
>can't supply the bulk of our needs long enough into the future
>so as to be essentially man-infinity. Apparently at least Georgia
>Power sees it that way too. The Prez of the utility spoke this week at
>a civic club meeting in Marietta. He said he expects Ga power to
>be generating the bulk of their power with nuclear into the next century.
>Since Ga Pwr now generates only about 20% nuclear, that implies a
>significant construction program in the not too distant future.
>He demurred when ask about plans for the next reactor.
>
>John
>--
>John De Armond, WD4OQC | For a free sample magazine, send
I think the Prez of the Utility was out here touring the IFR along
with Alabama Power,TVA,..Bottom line... The US Senate Energy and
Natural Resources comittee lead by Bennet Johnson explicitly stated
that if a technology such as IFR is curtailed, then fusion would
also get the axe. Utilities must invest in advanced reactor and
fusion research if the technology is to be percieved as economically
viable.
There are a laundry list of technical challenges to both inertial and
laser fusion. ANd we all know the hype of "cold fusion". The problem
with fusion is that currently, fusion studies are a physicists'
playground. The development of this energy source has been primarily
peace-time physics/computational research (save Teller's initial
work). First wall confinement, and electrostastatic (Coulombic
repuslion) are technical problems, but there is no infrastructure
for fusion on a commercial scale, as LWR technology has enjoyed
with the crossover from Navy applications.
____________________________________________________________________
Peter L. Angelo EBR-II Reactor Physics
Argonne National Laboratory-West IFRO Division
email pan...@anl.gov Idaho Falls,ID
"O.K. you guys, coffee break is over, everybody back on their heads.."
(The Univ of Chicago and ANL/DOE are absolved of my sins)
____________________________________________________________________
Erik Sorgatz
question actually...) It is because the status quo demands that the energy
available cost a fixed percentage of the nominal income; if fuels become
cheap, governments add taxes to prop-up the prices...RTFM the last 50 years
of the US petroleum-based energy pool and the ever increasing taxes being
levied. As the oil industry became partial owners of the nuclear industry,
it was clear that "fusion would replace fission in 25 years or so..". As
the truth about the conventional fissle fueled reactors and the industry
that built and supported them came out, the 'Energy Industry' (formerly a
clatch of 20 or so oil, gas and coal companies) decided to bail out, but
there remained this one little EXPEN$IVE problem...who's going to pay for
the cleanup, decommissioning and burial of the fission-reactor era?
Well, it was decided that YOU and everyone of the energy consumers in the
US was going to be stuck with the bill for the cleanup, what little they a
re actually going to do..a spot here and there...some 55 gallon drums into
a few salt mines..oh yeah...and meanwhile, fusion is still "25 years or so
away"...are you beginning to see the picture a little more clearly now?
Besides, the damn things are loaded with hard rad, and they can only boil
water anyway...not a very hi-tech mechanism at all...
-Avatar-> (aka: Erik K. Sorgatz) KB6LUY +----------------------------+
TTI(e...@soldev.tti.com)or: sor...@avatar.tti.com *Government produces NOTHING!*
3100 Ocean Park Blvd. Santa Monica, CA 90405 +----------------------------+
(OPINIONS EXPRESSED DO NOT REFLECT THE VIEWS OF CITICORP OR ITS MANAGEMENT!)
Tino
>Maybe - just maybe - there's a path to the flux*density*duration
>products we want for D-T, even D-D. There seems to be room for
>radical ideas. It's an enviable time to be a graduate student in
>plasma physics.
Yea--unless you enjoy eating. The last guy who got a PhD in plasma physics at
Purdue is working for minimum wage because there isn't anymore funding for it.
No thanks.
Tino
--
-------------------------------------------------------------------------------
"Chicago: invisible hierarchy of decorticated wops, smell of atrophied gangsters, earthbound ghost hits you at North and Halsted, Cicero, Lincoln
Park, panhandler of dreams, past invading the present, rancid magic of slot machines and roadhouses. Only the young bring anything in, and they are not
young very long..." - William S. Burroughs
Bruce Scott
>sa...@number2.cs.latrobe.edu.au (Jonathan Burns) writes:
>>Maybe - just maybe - there's a path to the flux*density*duration
>>products we want for D-T, even D-D. There seems to be room for
>>radical ideas. It's an enviable time to be a graduate student in
>>plasma physics.
>Yea--unless you enjoy eating. The last guy who got a PhD in plasma physics at
>Purdue is working for minimum wage because there isn't anymore funding for it.
>No thanks.
This is all too correct. This is a terrible time to enter the fusion
program, not only because it is in danger of dying out but also
because of the decision made in the 1970s that fusion was no longer
research but development. We have been essentially locked in ever
since. The realisation that transport was going to be a very difficult
problem has mitigated this somewhat, but only within the tokamak
sphere. "Development" means essentially that what people the program
does take on tend not to be physicists. A control engineer, on the
other hand, could jump into this field and out again, and still have a
career.
There is room for radical ideas, but little hope that they will be
funded. That is, beyond a few ecentrics at Toyota with more money than
they could burn having fun with cold fusion, able to say that they are
visionaries for human progress. As long as Toyota can sell cars,
no-one cares too much that they dump USD 11 million or so into cold
fusion.
In Germany, most people who get into plasma physics study light
sources and then (before the just-beginning 20-year recession hit) go
work for Siemens or Phillips. Competitiveness, and all that.
T Orth FP/207/ 8505
I'm sorry...but I guess if your going to dream, you might as well dream
big. I was just trying to stay grounded in reality. The best direct
conversion I can think of would be to funnel the reaction products
through a magnetic field as "current". One of the problems that I
understood to be a problem with current tokamaks was that fusion
products in the plasma..inhibited future fusion events by
their mere presence. If it is that easy to take these ions and remove
them from the plasma, than why hasn't anybody done it? let alone do it
in a way as to do direct conversion. I admit, I am not doing research on
fusion..but some common sense questions are being ignored by statements like
"materials for first walls aren't important because we will use direct
conversion anyway" .
In my best Wayne's world voice...Teya...as if
Gary Coffman
>
>HUH????? The reason that fusion is even considered worthwhile for generating
>electricity is because it releases HUGE amounts of energy. This energy is
>in the form of kinetic energy of particles (gamma and charged). This HEAT
>would be used in a heat engine...probably Rankine steam cycle of some kind.
>The notion that the charged particles resulting could generate electricity with
>the ions in the plasma is well....I just don't know what to say...ridiculous
>I guess.
Ever hear of MHD Tom?
Gary
--
Gary Coffman KE4ZV |"If 10% is good enough | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems | for Jesus, it's good | uunet!rsiatl!ke4zv!gary
534 Shannon Way | enough for Uncle Sam."| emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244 | -Ray Stevens |
T Orth FP/207/ 8505
Yeah, sure, there are lots of analogies out there that fit loosely to a lot
of things. But, I won't waste anymore band width on this. The point is
simply that direct conversion brings up a whole new set of engineering
problems..when the original poster suggested that it would eliminate the
need for a first wall to sustain high fast neutron flux.
John De Armond
>Actually, this (the idea that fusion will be a nice, clean energy
>source) is a popular misconception. The most likely plasma hot-fusion
>scenario is tritium-tritium or at least tritium-deuterium fusion, both
>of which produce scads of neutrons and lots of messy neutron-
>activation products,
Agreed. Fortunately, nothing we'll have to worry about in our lifetime
nor probably will our kids.
>not to mention that they use tritium, which is a
>pretty hazardous radioisotope (hard to contain, and it *loves* to get
>into people, who are perhaps 1/3 hydrogen by nucleus count).
Actually tritium is pretty harmless as a radioisotope. With a single
very low energy beta (14kev?) and a long half life, it is pretty
innocuous. True, it enters the body readily but it exits about as
quickly. From memory, the biological half-life is only a few days. A
good indication of relative hazards is the concentration limits for
various isotopes. From an old table, in water, the MPC for tritium is
3E-3 uCi/cc while Sr-90 is 3e-7 uCi/cc. big difference. Heck, I even
have half a curie on my wrist right now and another curie in the
backlight in my DVM.
A much larger problem will be the administrative nightmare stemming from
safeguards associated with tritium being a SNM. Mantaining an inventory
of tritium in a commercial scale plant would not be a job I'd want to
have.
--
John De Armond, WD4OQC | For a free sample magazine, send
Performance Engineering Magazine(TM) | a digest-size 52 cent SASE
Marietta, Ga "Hotrods'n'computers" | (Domestic) to PO Box 669728
j...@dixie.com "What could be better?" | Marietta, GA 30066
Email may be published at my sole discretion.
Paul Dietz
>>3He would have to mined in space if this were to be done on a
>>large scale, granted.
>
> 3H decays to 3He with ~10 years halflife. If you make a 10-year supply
> of tritium in the form of tritiated water, you ought to be able to
> collect the 3He as it bubbles off.
But doing this reduces d-3He to a minor offshoot of the
tritium-producing system. For example, if the tritium is made by
irradiation of lithium in a fission reactor, you end up producing much
more energy in the fission reactor than you get from the d-3He fusion.
So you might as well just stick to fission. You can do a bit
better harvesting tritium and 3He from d-d or p-6Li, but it's still
not very satisfactory.
In the far future, 3He would get mined in the atmosphere of Uranus
(which has a higher He/H ratio and lower escape velocity than the
other gas giants). The He isotope data from Galileo will be of
interest here.
Paul F. Dietz
di...@cs.rochester.edu
Mike Van Pelt
>3He would have to mined in space if this were to be done on a
>large scale, granted.
3H decays to 3He with ~10 years halflife. If you make a 10-year supply
of tritium in the form of tritiated water, you ought to be able to
collect the 3He as it bubbles off.
--
Mike Van Pelt "I'm not a biologist, but I play one in
m...@netcom.com front of Congressional hearings."
m...@lsil.com -- Meryl Streep
P Angelo /RA/208G/osra 7550
>zo...@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:
>
>>Actually, this (the idea that fusion will be a nice, clean energy
>>source) is a popular misconception. The most likely plasma hot-fusion
>>scenario is tritium-tritium or at least tritium-deuterium fusion, both
>>of which produce scads of neutrons and lots of messy neutron-
>>activation products,
>
>>pretty hazardous radioisotope (hard to contain, and it *loves* to get
>>into people, who are perhaps 1/3 hydrogen by nucleus count).
>
>Actually tritium is pretty harmless as a radioisotope. With a single
>very low energy beta (14kev?) and a long half life, it is pretty
>innocuous. True, it enters the body readily but it exits about as
>quickly. From memory, the biological half-life is only a few days. A
>good indication of relative hazards is the concentration limits for
>various isotopes. From an old table, in water, the MPC for tritium is
>3E-3 uCi/cc while Sr-90 is 3e-7 uCi/cc. big difference. Heck, I even
>have half a curie on my wrist right now and another curie in the
>backlight in my DVM.
>
>A much larger problem will be the administrative nightmare stemming from
>safeguards associated with tritium being a SNM. Mantaining an inventory
>of tritium in a commercial scale plant would not be a job I'd want to
>have.
>
>--
>John De Armond, WD4OQC | For a free sample magazine, send
The next time you change your watch battery, look at the power source..
You will be suprised. BTW H3 by itself would not be considered SNM
since you still need Pu to trigger the H bomb. I think SNM is
considered fissionable transuranics.
Also, consider the concept of muon-catalyzed fusion. The people at
Los Alamos have been kicking this around for quite some time. There
seems to be a problem with "alpha sticking" whereby the muon is
absorbed in He-4 and not allowed to continue the catalysis. Some
researchers have postulated that "cold fusion" as was evidenced was
a result of muon catalyzed fusion whereby the muons evolved from cosmic
ray particle transport. ANy thoughts?
John De Armond
>In this we are still paying for the enthusiasm of people who in the
>1950s paid no attention to the emerging science of turbulence, and
>thought that the production of an MHD-stable magnetic plasma
>confinement device would be sufficient to make fusion. You see, if
>thermal and particle transport were really caused solely by
>collisional diffusion, we would have been producing fusion for the
>last 20 years or so.
>Unfortunately, it is not like that. Small fluctuations in density or
>temperature cause small electric field fluctuations, since the
>electrons (with their smaller mass) tend to run away (along magnetic
>field lines) from a compression much faster than the ions.
Bruce, THAT was enjoyable. A post that made me work the old noodle
a little AND a frank assessment of Fusion Today (tm).
>I'll worry about this when the time comes. Population-growth-induced
>environmental problems will be all over us before fusion power comes
>on line. Obviously, all those brilliant statements at last year's IAEA
>meeting about how fusion is the hope of all those Third-World masses
>who want Western-level energy consumption are pretty laughable.
True. Now a question. What would your best guess be as to what
process/technology might result someday in actual usable power
from fusion? And a related question, assuming some sort of fusion
plant capable of roughly the same power output as present
day fission plants (1000 MWe, perhaps 2500 MWt), what would be some
of the magnitudes involved? Neutron flux? Reactor size? Size/thickness
of a breeder blanket? What types of materials might withstand
the radiation and thermal environment? In other words, as the result
of a little brainstorming, what do you think a plant might be like?
Thanks,
John
--
John De Armond, WD4OQC | For a free sample magazine, send
John De Armond
>The next time you change your watch battery, look at the power source..
>You will be suprised.
I'm not sure what to be surprised about. My mil spec watch does not use
H3 as a power source. It does, however have nifty little luminous capsules
of H3/phosphor on each of the hands and at each of the numbers.
John
--
John De Armond, WD4OQC | For a free sample magazine, send
cheu...@esvx11.es.dupont.com
This is just a thought......
Recently , Scientific American published an article showing how a chaotic
motion could be stabilized. It might be a little far-fetched but what if the
same method is applied in the containment chamber. There aer probably a whole
set of equations that could act as guides to the geometry of the plasma
turbulence. With the new superconducting materials that works at higher
temperatures, and a method of using the magnets to induce stochastic cooling
with the help of faster electronics to control the magnets....i don't know
i've been following the various methods for MHD since junior high.
Using the areas where most of the fusing would take place according to the
chaotic equations , harnessing the energy in those areas, and exploring the
deeper chemistries of various stars.
Just thinking.....
In article <1993Sep15.1...@cs.rochester.edu>,
di...@cs.rochester.edu (Paul Dietz) writes:
Bruce Scott
cheu...@esvx11.es.dupont.com writes:
>Recently , Scientific American published an article showing how a chaotic
>motion could be stabilized. It might be a little far-fetched but what if the
>same method is applied in the containment chamber.
You are probably thinking about chaotic particle motion here.
The trouble is that in a plasma the particles and fields act upon one
another. There are instabilities which arise from the fact that in a
confined plasma there are gradients in density and temperature, and
these serve as local sources of free energy for fluctuations in
density, temperature, and electric field (perpendicular to the
background magnetic field). All three of these drive each other once
any one is excited, since they are all coupled (the flow of electrons
is slightly compressible). Although there are regimes in which no
*linear* instability is known (the sort in which perturbations grow
from infinitesimal initial amplitude), it seems that finite-amplitude
instability is always present (B Scott, Phys Rev Letters, vol 65, p
3289, Dec 1990). In this case, "finite amplitude" means that the
relative amplitude of a density fluctuation, delta n/n, need be about
as large as an ion gyroradius divided by the scale length for the
background gradient. This is about 0.01 in a small tokamak and will
be more like 0.001 in a reactor. This instabilty appears to be
unavoidable.
In the plasma edge region, where the magnetic field lines come in
contact with material boundaries, there are even stronger
instabilities, which are probably the reason that relative amplitudes
are so much stronger there (about 0.1 - 0.3). See Berk and Ryutov,
JETP Letters, vol 52, p 23 (1990); Phys Fluids B, vol 3, p 1346
(1991).