Combining New/Old Approaches for Nuclear Fusion 320
L2 writes "Sandia National Labs are looking at some old military tech for a shortcut to nuclear fusion. Still the odd little detail to be worked out, such as how to keep the fuel from melting everything during the reaction. " Interesting approach. While much of the recent fusion work seems to have centered around tokamak reacters, from what I've seen, this one harkens back to a different school of thought. The bottomline, IMHO, is that the sooner we have fusion - or another cheap, environmentally clean energy source, the less likely we are to destroy the rest of this planet and hence ourselves.
Re:Uninformed fears of nanotechnology. (Score:1)
yeah, it was called "BOB" and was real friendly. It kept on smiling as it sucked my soul out the parallel port. Ran in only 1 Meg of RAM too!
Then I traded my 386 for a leather jacket and bought a Mac.
My Willow [alysonhannigan.com] desktop picture keeps evil at bay as I wait to install LinuxPPC.
All is going according to plan...
Pope
Re: Fusion is a LOT more DANGEROUS than coal (Score:1)
Re: (I'm a moron) (Score:1)
Gotta love newbies! =)
think about stars (Score:1)
You'd think that pysicists would think about how fusion happens in stars. Heat is incidental. Pressure is what makes atoms fuse. Hot fusion is a waste of energy. Sure, if you make atoms move around really fast, some of them will fuse. There are other ways to create pressure among atoms, and they take a lot less energy than a giant donut shaped oven.
Not fusion (Score:1)
It is a plasma.
It is not fusion.
Fusion is a nuclear thing, not an electronic thing. You have to smash atoms into eachother so that the nuclei combine, not so that the electrons get excited. If the point of your comment was that it's difficult to control said reaction then you're absolutely correct. If you were trying to suggest that one can do fusion in a microwave oven then you've been misled, I'm afraid.
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To hell with you, I never liked you, you are no friend of mine...
Re:Nothing environmentally clean about fusion. (Score:1)
Long, but not too long.
Yes, we do have a great source of fusion generated power: the Sun (or more specifically solar-power, wave-power, bio-mass, ...) but it isn't enough to meet projected energy requirements. There's a report by the EU (sorry, can't remember a source off the top of my head) that looked at all the available sources of energy (including fission) and there just won't be enough to go around without something happening. The report was pro-fusion so it recommended that the "something" be the development of fusion reactors.
appropriate technology (Score:1)
Re:My thoughts (Score:2)
Well, at least this is what I remember being told, and might have it a bit mixed up. Fairly often I can talk to a lead engineer on the NIF (LLNL) project.
Myths of Fusion -Re:So they're getting closer... (Score:1)
Every fusion scheme mentioned on this thread has problems with radioactive waste. Period.
The current batch of 20-year olds will burn up all of the remaining fossil fuels in their lifetime. Long before that fossil fuels will become too expensive to use. We need to begin developing massive solar and hydrogen gas economies now. If they are not on-line when the Carbon based fuels run out we won't have enough trees in the entire country to keep us warm one whole winter.
JLK
Re:Fusion ain't clean ... (Score:3)
plants, would the waste production be higher or lower?
Sure.
In fact, it's easy to show that fission produces _less_ waste - the question is how much less.
DISCLAIMER: I AM MAKING LIBERAL USE OF "FERMI" ESTIMATES. NUMBERS QUOTED SHOULD BE WITHIN AN ORDER OF MAGNITUDE OF REALITY, BUT THAT'S ABOUT IT. THIS IS NOT A DETAILED ESTIMATE.
Both fission and fusion produce secondary waste, in the form of the reactor housing, which becomes radioactive. The housing won't last forever - pieces wear out, as with any device. Let's assume as a rough approximation that the entire thing has to be replaced once every 20 years, and that it is all filed as low-level radioactive waste.
Let's assume that we have a moderate-sized reactor core - a 10m cube (30 feet for the American audience). This isn't a solid structure; in a fission plant, it's a framework holding reactor rods, and either a containment vessel (American reactors) or a network of pipes (Canaadian reactors), with ample amounts of radiation shielding. Let's say it's equivalent to a shell 2m thick. This gives us a volume of about (10^3 - 6^3) = around 800 cubic metres. Assuming a density of around 5 (metal, concrete, and lead), we get about 4000 tonnes of waste every 20 years, or an average of 200 tonnes of waste per year (1 tonne = 1000 kg = about 2200 pounds, so about the same as a US ton, before you object to my spelling).
Now, a fission reactor also produces a fair bit of high-level waste in the form of spent fuel rods. This represents extra waste that a fusion reactor doesn't produce. We have to see how much it is compared to the (roughly) 200 tonnes produced on average per year by our hypothetical reactor.
Let's assume that a reactor with a core of the quoted size produces about 500 MW of power. Let's assume that this represents about 2% of the fuel in the reactor (typical of fission reactors that don't use reprocessed fuels). Let's assume that this fuel converts mass to energy at an efficiency of about 0.1% (typical for fission reactions, IIRC). 500 MW over one year gives us about 1.5e16 joules of energy produced per year. At 100% efficiency, this would correspond to about 0.17 kg of fuel. We're operating at 0.1% efficiency, which means about 170 kg of fuel burned. This represents about 2% of the total amount of fuel, which means about 8.5 tonnes of fuel burned in the reactor per year. This fuel is filed as high-level waste when its finished burning.
So, we find that, unless I'm off by _more_ than a factor of 10 in computing the _relative_ amounts of each type of waste, and assuming that you consider high-level and low-level waste equally bad, both fusion and fission produce about the same amount of waste, most of which is just parts of the reactor that wear out and have to be stored safely.
CAVEATS:
A few notes about fission, that might be confusing people:
A conventional fission reactor has two fuel sources; U235, which is present from the start, and Pu239, which is bred from U238 within the reactor (any reactor containing U238 does this whether you want it to or not). Both of these fission to produce many light byproducts. These byproducts occasionally absorb neutrons, and almost never give them out. After you've left a rod in the reactor for a while, enough of these byproducts accumulate that reactions are not self-sustaining within the fuel rod anymore. It is absorbing neutrons without contributing much energy. This is after somewhere around 2% of its mass has been fissioned. At this point, you can either throw it away or send it to a reprocessing plant, which strips out the light, absorbing components so that you can use the rod again. Nowadays, we throw the rods away and lose 98% of its mass.
Reprocessing isn't done any more because it involves running what amounts to high-level waste through a chemical processing plant. Despite precautions, this resulted in unacceptably high exposure to radiation for people working in the plant. Neutron radiation from the waste also transmuted anything that the waste was in contact with (including whatever you dissolve it in for processing, and so forth), producing a lot of low-level waste. The result of all of this is that reprocessing fuel rods safely is a hassle of monumental proportions. There's enough uranium lying around that we can afford to throw away 98% of it, so we do.
Should be _FUSION_ produces less waste... (Score:2)
Horrid typo.
That should read, "fusion produces _less_ waste".
Re:Military Technology != Public Technology (Score:1)
---
"'Is not a quine' is not a quine" is a quine.
Re:Is fusion *really* a boon for the environment? (Score:2)
Most power sources are not a boon to the enviroment. Many fusion reactors are also poorly built, using designs that are fundalmentally flawed. Reactors can be made to never melt down, though most are cheaper and a more 'popular' style choosen by politicians. I really doubt that the heat from nuclear reactions will drasticly hurt the enviroment, though I'm not sure about the changes in heat output. You might find something when looking at the laser projects over at llnl.gov, where they have resources on fusion and fission.
Re:Not yet (Score:1)
We could, maybe, base an economy on thunderstorms. (Score:2)
These towers would essentially contain permanent thunderstorms. I haven't re-done the author's numbers, but he claimed that the mass-flow rate of such a tower would conservatively be in the thousands of tons per second, and the air leaving the tower would be moving at upwards of 200 MPH. He calculated such things as the fresh water yield of the "rain" inside the tower and the hydropower available from letting it fall down pipes, but the real yield is the airflow itself. I calculated the power available from the moving air, and with (what seemed to me to be) reasonable assumptions about efficiency I got the number of 22 GIGAWATTS. From one tower.
For reference, the total nameplate generating capacity of the generators in the USA is a mere 754 GW, according to the Department of Energy [doe.gov]. This means that 40 of these towers, arrayed along our coasts or around the Carribean, could replace every watt from every generator currently feeding the US electrical grid... and then some. They'd also make a hell of a lot of fresh water, and cool off the surface waters somewhat (a boon for heat-stressed coral reefs).
There's a lot more ocean out there than just our coasts, and it's all getting warmer. Tapping energy off it would not only replace fossil fuels directly, it would also do some global-warming abatement by dumping heat above some 8 miles of atmosphere where it has an easier time escaping. I think we could do a lot worse than checking this out in detail again, and if it would work, pushing it like hell.
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Re:My thoughts (Score:1)
I'm picking nits, but the advantage to nuclear-powered submarines is that they do not need an air supply to run their diesel generators. Thus they can stay under for weeks at a time.
Re:Myths of Fusion -Re:So they're getting closer.. (Score:1)
How the H-Bomb solved the symmetry problem. (Score:3)
What's interesting is that much of this confusion has to be intentional misinformation.
Why? Because it was the solution to the symmetry problem which was the key to the H-bomb. The complete discussion of the concept remained officially classified for decades after the H-bomb was invented. In contrast, the basic physics and outline of the engineering behind the A-bomb was made public in the 1940's already.
Some details had leaked out in one way or another by various 'exposes' but nothing really got it right. I believe it was finally declassified in about 1994 or so---I remember the article in the New York Times. By that point, intertial confinement fusion civilian researchers had already figured it out.
The trick is 'radiation driven implosion'.
The soft x-rays from a fission explosion are diverted down to a hollow tube (hohlraum {hollow room} in the German used by the early researchers). There is in fact a barrier, usually
of tungsten or some other heavy material directly in between the fission primary and the fusion secondary. This is to prevent the explosion of the fission material itself (the stuff) from getting to the fusion part and ruining it. You just want the photons, and if you block the shrapnel, the photons get there first.
The primary is basically many spherical layers---the secondary is a long cylinder with a few coincentric layers, with a gap near the outermost layer for the photons to flow into.
This form a 'photon gas'---but this fluid equilibrates at the speed of light and not the speed of sound, like normal fluids. Which means that the density and energy of the photons gets very uniform quickly. Although you don't normally feel it in every day life, photons carry momentum and can exert a pressure.
The A-bomb uses chemical explosives to precisely compress the fission fuel, but that isn't powerful and even and fast enough to work with fusion. The description in the article, putting the fusion fuel in the center of the bomb, is mostly incorrect. There is a little bit of fusion fuel in the middle of the a-bomb section but it does not make the really big BANG of the true H-bomb, it is just a booster to make more neutrons to make more fission from a given amount of plutonium or uranium.
Back to the photon fluid. This photon gas has enough energy to very very evenly and violently compress the fusion fuel. This is basically a 3-layered hot dog. The outermost layer is a heavy 'tamper' of lead or U-238 or something else. The middle layer is the fusion fuel. Then, there is a rod in the center with fission fuel like U-235 or Pu-239. The photon gas ablates the material on the tamper---the pressure from the photons and momentum from the ablation compress the fusion tube very severely. At the same time, it is magically arranged for just enough neutrons from the primary fission explosion to start a chain reaction in the fission stuff inside the fusion fuel, known as the 'spark plug'. Thus the fusion fuel is compressed from the outside by the photon gas and ablation and squeezed from the inside from the second fission explosion. This is how much work you need to do to get fusion. The fission material, normally very light, is compressed to a density near that of a white-dwarf star, where it reaches quantum mechanical Fermi degeneracy. That is really really really compressed. Not quite a neutron star (that is even more dense, being a giant atomic nucleus) but still thousands of times more dense than any conventional material.
Then, Boom.
The symmetrical lasers in the Livermore fusion experiments do NOT directly shine on the fusion pellet. That would not make sufficiently even compression. They shine on an outer metallic sphere which ionizes and releases X-rays, and these X-rays equilibrate inside the metallic shell (even though it's now totally vaporized it's still heavy compared to photons) and this compresses the fusion fuel.
This is why the intertially confined fusion program is always more classified than the magnetic fusion, because it is in large measure H-bomb technology. The "national ignition facility" being built for the DOE in the United States is yet another really big ICF project. Unfortuantely for political reasons it is being designed entirely from the point of view of military bomb research and not for any energy research. I think that's a shocking waste but there's a gazillion dollars to test the most obscure things about nukes when we already have thousands of bombs that work way way too well for our planet's and species' good.
The lasers are very power inefficient, but better for getting clean data for bomb research. Ion beams, and probably this Sandia machine are much more power efficient and the likely technology for a power plant, but less is known about them because it doesn't fit in the military application as well.
In any case, it is almost certain that this Sandia machine described in the article uses "indirect drive" {as the x-ray compression method is known} instead of "direct drive" and that is how they plan to work on the symmetry problem. So they probably do have an idea what to do about it, contrary to what the article says. It is still a very challenging problem, but not hope is lost.
The best information on the web about Big Bombs is Carey Sublette's archive. Just about everybody who Really Knows what's going on {and I'm not one of them} has said that the technical details are accurate. In fact, some of the information about the W88 warhead that the Chinese supposedly stole can be found on this website, and the Chinese showed this in their defense.
[fas.org]
High energy weapons archive
I am a physicist, but not a nuclear physicist or involved in fusion research in any way whatsoever.
Solution to heat pollution (Score:2)
Heat pollution is indeed a problem, both at the reactor and in the cities where the power is used (most power eventually ends up being converted to heat). However, there is a safe place to dump the heat if it becomes a sufficiently bad problem - the sky.
Space has a black-body temperature of about 3 kelvin. Use heat pumps to concentrate your heat in a working fluid. Run the fluid through pipes. Put the pipes in mirrored channels, open at the top. Most of your heat goes into space, by blackbody emission from the pipes.
The problem with this is the rate at which heat is dumped. This is proportional to the fourth power of the temperature of your working fluid (and hence your pipes). The bad news is, you need a very hot fluid. The good news is that, because of the fourth order relation, your fluid doesn't have to be _insanely_ hot. The heat pump that performs the concentration will produce heat itself - you're working against entropy when concentrating heat like that. However, if all components are efficient enough, you should be able to dump this heat out with the rest.
This requires power. I am blithely assuming that if you have enough power plants that heat pollution is a problem big enough to do something about, you have enough power to run the heat pumps.
This doesn't work on cloudy days. I am blithely assuming that you have a heat sink large enough to store heat in until the next clear day. This would probably be a moderate-sized body of water.
Assuming that you can afford a one-hectare area per GW of heat for your emitter array (100m squared, or _roughly_ 100 yards by 100 yards), and that one quarter of this is actual emitting area (area of the pipes), your working fluid would have to be at a temperature of about 1600 kelvin, or about 1330 degrees centigrade. This is readily buildable. The only concern is the heat pump, which is working against a very strong temperature difference. Scale up the area - to, say, 1km by 1km (about 0.6 miles by 0.6 miles), and you need a temperature of about 515 kelvin, or about 242 degrees centigrade. Building the heat engine for this is much easier, though more of the resulting radiation will be absorbed by the atmosphere in that frequency band. Maintaining the array is more expensive in this scenario, too.
In conclusion, I think that heat pollution is a solvable problem. It just requires enough of an investment that we aren't likely to build heat-dumping plants until they become absolutely necessary.
Re:think about stars (Score:2)
Um, no, there aren't.
Not the required amount of pressure.
Even the sun doesn't produce enough pressure to physically force the nuclei together. The core of the sun is electron-degenerate - you have electrons in a strictly organized set of energy levels, with nuclei zipping around like gas particles within it.
Most of the nuclei, even in the sun's core, don't have enough energy to overcome the electrostatic repulsion between nuclei. A very few of them do - because the temperature of an object is only the _average_ temperature of the particles within it. It is very rare for a particle to gain this much energy, and so fusion reactions are extremely infrequent for a given particle, but the particles aren't going anywhere, and there are a lot of them. Thus, the sun produces a substantial amount of energy due to fusion.
On earth, there are very strong limits to the pressures we can produce stably. A steady-state system would therefore have to jack up the temperature to increase the reaction rate in order to generate more energy than it expends. You could argue that a steady-state system isn't necessary; well and good. However, when you produce a region of extreme pressure (as with inertial-confinement fusion), it doesn't last very long. You jack up the reaction rate, but the short confinement time brings your total power output back down again.
This covers all but two proposed methods of fusion.
One other method proposed is muon-catalyzed fusion. Click on "user info" above to find a message with more details about it. It uses a very sneaky method to remove most of the cost of bringing nuclei close enough together to fuse. However, the energy cost of the muons required for catalysis is far more than the energy produced by the catalyzed fusion.
The last method proposed of producing fusion is the "cold" fusion that caused such a media commotion recently.
People would very much like this style of fusion to work.
People claimed that they had gotten this style of fusion to work.
A number of countries invested and continue to invest substantial research energies into duplicating the original experiments that supposedly reliably produced energy by fusion by this method.
To date, they have failed. This, coupled with a number of extremely suspicious points in the presentations by the original discoverers, strongly suggests that the original researchers were either mistaken or actively defrauding the rest of the scientific community. Read the book entitled "Yes, we have no neutrons" for an in-depth discussion of this. Authour name escapes me at the moment.
Summary: Cold fusion appears to be bogus, despite much effort to duplicate it.
So, what method are you proposing to create the pressures necessary to produce fusion at room temperature?
Doh! (Score:1)
Practical approaches to solar. (Score:2)
Firstly, atmospheric attenuation isn't *that* much. Even a factor of two power loss still leaves 500 W/m^2, which is respectable.
Secondly, regarding storm damage and cost of solar power facilities. If a solar facility was built as an array of photovoltaic panels, then it would indeed be very expensive to produce and to maintain (at least until very good thin-film photovoltaics get here). However, there are a couple of workarounds.
Both workarounds involve using concentrators. The idea is that mirrors are quite cheap, especially if they don't have to be of laboratory quality. Run a set of metal troughs aligned to be parallel to the sun's course (on average). Make them out of aluminum so that they won't rust, and put drainage holes in them in case it rains. Run a strip of photovoltaic cells down the channel, suspended at the focus of the mirror. This reduces cost substantially, and may also increase efficiency (several types of cell work better in brighter light).
A variant of this dispenses with photovoltaics and runs black pipes down the channels, again suspended at the focal point. Put a working fluid in the pipes, and run a conventional heat engine off of them. You need somewhere to dump the heat, but if you're near a body of water that's not a problem (heat pollution is another issue).
For space-based power, you can do much the same thing. Most of the area of your power satellite is made of cheap aluminized-mylar reflectors. Yes, they'll be shredded after a while, but you can replace them (or the entire satellite, if you want). At the foci of these reflectors are either photovoltaic panels or heat engines. These are small enough that you can put some micrometeorite shielding around them to extend their lifetimes.
This gives you a lighter satellite, that might even last longer, and is certainly much cheaper to replace.
The main problem with power satellites is that you have to beam the power back down to earth. This does not present a terrorism hazard - the most popular schemes use the receiving antenna array to control the phase of the beams produced from various parts of the satellite. Without this control, the satellite would emit in all directions, resulting in harmless power levels reaching the ground. This control takes a big array, and the resulting beam is targetted _at_ the array. So to fry a city, the terrorist group would first have to put an appropriate antenna on the roof of every home... Maybe offer to clean their eavestroughs while there...
The real problems with beaming power back are that your emitters have to be a fixed weight no matter what - which puts a lower limit on the mass of the satellite - and that you need substantial levels of microwave energy coming down on your receiving array (i.e. more than 1 kW/m^2). Any bird flying through this will get warm, and anybody camping out underneath will get warm also. They won't be flash-fried - but they will receive the equivalent of standing under light several times brighter than the sun.
Lastly, as this represents energy imported to earth, power satellites will contribute to the heat pollution problem. OTOH, the same applies to any other power source that releases energy that would otherwise not be released on earth.
The final way to (efficiently!) use solar power on earth is to grow crops and ferment them to produce methanol. This gives you a flammable liquid that can be used as fuel, mulch to supply the hydrocarbon/chemical industries, and takes carbon dioxide out of the atmosphere as fast as fuel-burning puts it into it.
The problem is that the crop method takes up a fair amount of space, and (like other forms of solare power) is limited by the amount of sunlight falling on to the collectors/fields.
Re:Fusion ain't clean ... (Score:1)
3H2 -> He4 + p + n
and the reaction formula
H2 + H2 -> H3 + p
H2 + H3 -> He4 + n
No neutrinos are formed; that is only true for proton fusion (where some protons get converted to neutrons, releasing an positron and a neutrino.)
Energy will never be very cheap (Score:1)
Re:Military Technology != Public Technology (Score:1)
I've been in the military, I think that should be rephrased to
'10 years ahead of what the GENERAL public has access to.'
Erik Z
Re:Military Technology != Public Technology (Score:1)
Military Technology != Public Technology (Score:1)
Does the military already have fusion?
The Problem is more Immediate (Score:1)
Re:Military Technology != Public Technology (Score:1)
WWII was ended by the Japanese capitulating, repeatedly. Theny needed to repeat themselves because the allies ignored the first capitulation, the americans because they wanted to play with bombs and the soviet union because they wanted Japan.
"Just because it isn't nice doesn't mean it isn't a miracle."
-- Terry Pratchett
"Just because it isn't nice doesn't mean it isn't true."
-- Me
How to build your own Fusion Reactor (Serious) (Score:1)
Without tracking my copy down (It's somewhere on the bookcase of Analog's that goes back to 1953), it uses two spherical frames of wire to repeatedly accelerate ions through a series of orbits around the centre of the device, and as the ions fall towards the centre (very fast) a few will collide and fuse, and emit energy.
Warning - this actually does emit enough neutrons to be a health risk. And you are messing with 15,000 volts, which will not make you a happy person if you mess up.
It doesn't have anywhere near the efficiency needed at this time, but it doesn't require high temperatures, instead it uses high electron-volts to do the work.
Links to people who know more about it than I :
http://shoelace.digivill.net/~se raphim/theory.html [digivill.net] The original Author of the article
http://www.ticnet.com/bertpool/philo
Background on the inventor
Re:Military Technology != Public Technology (Score:1)
I'm sick of this kind of thing. (Score:1)
The more resources people have, the better off they will be. Sure, cheap power and goods will not bring spiritual fulfillment to all, but better resources can keep people from starving to death! Yes, people in "unconventional places" might be able to enjoy sanitary living, medicine, and better education. Rather than practice subsistence agriculture, they might then spend their time putting that education to use for everyone. Think of the good things people do with the resources they have and remember that ignorance is wasteful.
Power is the ultimate resource. It gives people the ability to modify the world around them in any way they see fit. It mines raw resources, processes them and assembles the results into the things you and I enjoy every day. Let's try to make more to share with everyone!
If you don't like cheap power, try trading places with some poor bastard living in a cave. In no time, you will learn that other people have greater problems than dull food. You have the choice to live where you will, most people don't. That choice was given to you, pass it on.
Re:Military Technology != Public Technology (Score:1)
Wasn't he the one who suggested that the forst A-bomb test might just eradicate the whole atmosphere?
Just out of curiosity... (Score:1)
Alas (Score:1)
Re:Just out of curiosity... (Score:1)
Symetry is needed? (Score:1)
Re:Cheap, (Score:1)
(Wake up on the wrong side of nobody this morning?)
Re:So they're getting closer... (Score:2)
No. For that matter, the (wo)men who invented the aforementioned were far, far, too bright to naively assume that they would. But you'd be a complete fool to argue that they haven't improved the quality of life.
Try to get a little historical perspective here: a hundred years ago you would (statistically) most likely be working well over 70 hours a week, six days a week, with no class mobility, and you would have done it since you were eleven. Your job requires an amount of tedium and manual labor that you can't comprehend now because you work in crowded, dangerious conditions doing things like grinding meat, forging steel (the old way), lifting giant, heavy objects, or any one of the millions of things that no one does anymore because _____ (fill in the blank) now does it automatically, or more easily, or less dangerously. In terms of today, your quality life is subzero. You have no car, and even if they existed in cheap enough forms would do you no good because you will probably never leave the urban area where you work and live. Telephones are a novelty, and the easiest way to communicate with relatives is still the postal service, which is unreliable and slow.
Think of any modern invention, and I can guarantee you that it hasn't solved our all problems. But I can also guarantee you that more than a few of them have solved one or two, and that adds up over the years. Will fusion power eradicate all pollution, bring back the wooly mammoth, and provide limitless, waste-free power? No. Will it provide a huge leap towards helping the environment? Yes.
--
"Some people say that I proved if you get a C average, you can end up being successful in life."
Clean? Yeah quite clean... (Score:2)
Imagine tons of disposed wires. Radioactive ones btw. Plus some other secondary equipment among this messy caroussel. Sincerly would not call it this way. I would better call it the Gatling gun scheme... Ra-ta-ta-ta...
Miarogers don't get it. (Score:1)
Now for the point.
Self inflicted scarcity is backward! Efficiency is a means, not an end. Your self loathing is a waste of personal energy. Your desire to punish others for perceived waste is awful. It will be a dark day if the US ceases to research reasonable potentially world benefiting research for fear of success!
Focus on the positive things people do with their resources and try to contribute. You were raised, educated and drive a Honda... don't you want such things for others? Like that 40 watts per square meter the sun throws? That's great, work on it make it cheaper and better. Not a rocket scientist? OK, the economy needs all types so just do what you can. The rest of the world will follow as it is able. People come to the US from all around the world to learn how we do things. Some surpass their teachers and contribute here, all are better off. Only more freely available resources can lead to better living conditions and education that prevent waste. The evil actions of some are no reason for you to give up.
It is the wealth of this country that have allowed you to the time to reflect on these things. That wealth is built on ever more efficient utilization of resources. The world needs more, not less, for others to enjoy what we do.
Do not limit your thoughts to the present level of production or the current relative wealth of the world. The entire world's population could be housed in a suburb the size of Texas. People in some places are indeed murdered by their supposed leaders who feel compelled to compete with them for a surplus of scarce resources. Most people, however, succumb to ordinary shortages of food and medicine. Changing this takes time, but it is happening. The Earth's resources are immense, and the resources of the universe are unlimited. The only real limit is our ability to manipulate these resources.
Re:Alas (Score:2)
In July, Sandia explained this same liquified fusion reactor module [sandia.gov] design on this web page. Includes diagrams and details of this interesting bit of engineering.
There is a summary of where we are with pulsed power engineering [sandia.gov]. Notice we're already at the point where we can take apart non-nuclear waste into its components, which allows detoxification and recycling.
There's other info about the Z-pinch methods [aps.org] elsewhere, if you're interested in nuclear engineering.
Re:Just out of curiosity... (Score:1)
The book "Indistinguishable from Magic" by Robert L. Forward has quite a bit on matter-antimatter engines, first chapter even.
Now, even though it's great efficiency, I have a hard time believing that an plant designed to create antimatter would be allowed on the planet.
Neat, but impractical.
Later
Erik Z
Re:Energy will never be very cheap (Score:1)
Re:Miarogers don't get it. (Score:1)
from LSU
that's great but it seems all of your exprience at school has yet to get through your thick skull. people don't starve because of a lack of resources, they starve because of greed. that's all I was saying. It seems there are too many college pricks such as yourself who assume just because you've sat through some classes you actually know what's going on. even if we get fusion tommorow it won't matter, because leaders starve their people, and their people will continue to die, the only people who will reap the rewards are us americans who already have too much power(as in watts).
and i only watch cnn and pbs, none of the crap most americans watch(sitcoms/cartoons mainly). cnn dosen't rot your brain, it makes your brain thrive, the same thing with pbs.
oh and saying "Miarogers don't get it." really makes you look uneducated. don't spell my name wrong, it is Jeremiah Rogers so therefore i go by miahrogers as a nickname. so you would say "Miahrogers doesn't get it", i guess your BS and BA didn't teach you anything about grammar.
Widomaker is my ISP, I also disagree with their choice of a company name, but they give me good service so I don't bitch about it.
matisse:~$ cat
Re:Just out of curiosity... (Score:1)
High Power Pulses (Score:1)
The juice comes out in 100-billionths of a second, resulting in a 290-trillion-watt pulse. That's about 80 times the entire world's output of electricity, but it only lasts a few billionths of a second.
One way to do this:
Connect an LC circuit with huge capacitance (and inductance to match) to a lighning gap in parallel. Charge up the capacitor. Discharge it into the inductor. At the moment of maximum discharge, remove the capacitor from the circuit with a very fast switch whose "off" resistance is a _lot_ higher than that of the lightning gap.
The energized inductor has no choice but to discharge its energy, in a very fast rise time pulse, through the lightning gap.
My MicroSim runs show it is easy to get discharges that spike in under 100ns this way. Building the huge capacitor, huge inductor and fast high-open-resistance switches may not be so easy, of course.
nukyaleer reacters (Score:1)
While much of the recent fusion work seems to have centered around tokamak reacters...
if'n nukyaleer reacters is outlawed, only outlaws is gonna have nukyaleer reacters.
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"Rex unto my cleeb, and thou shalt have everlasting blort." - Zorp 3:16
Re:Fusion ain't clean ... (Score:1)
Duh. That should be, "destroy the world," in case anyone's wondering.
Re:Fusion ain't clean ... (Score:1)
At lower sustained plasma pressure (one tenth that of p-B11), you can trade off energy against cleanliness with Helium-3 and Hydrogen-2 (deuterium). By varying the ratio between the two within the reaction mix.
Lithium-6 has a similarly low neutron reaction.
Techniques that produce extraordinarily high plasma pressures, even for a few miliseconds, are particularly valuable because they get into the regime where these aneutronic cycles are achievable.
Re: Fusion is a LOT more DANGEROUS than coal (Score:2)
So we'll be able to take remodel a fusion or fission reactor, dump all the radioactive stuff into the transmuter, and get non-radioactive stuff. Sure, some of the radioactive iron may no longer be the same iron isotope or may no longer be iron, but it can be separated and processed using ordinary chemical and manufacturing methods at that point.
We're already doing transmuting in the lab but energy is too expensive to do it routinely. But then we're talking about after energy is cheap...and the high-energy plasma available as a side effect of hot fusion will allow interesting engineering and manufacturing.
Thoughts on Fusion Energy Research (Score:3)
The official Department of Energy (DOE) Fusion program is in real trouble - trouble it deserves. Fifty years ago usable controlled thermonuclear fusion was 25 years in the future. Now it is 40 years in the future. They brought it on themselves.
A short bit of history. The Princeton University research team always dominated the program. They area brilliant but stubborn group. No idea that wasn't invented by them had a snowball's chance in hell. The problem is very tricky, heating a plasma (ionized gas) to tens on millions of degrees, and confining it with a magnetic field - as no material could withstand the heat. The Princeton Plasma Lab (PPL) came up with the concept of a Stellarator, a figure-8 shaped magnetic confinement field. This never worked. In the sixties it was scrapped in favor or the Tokamak. - a doughnut shaped field. While this was not invented at Princeton, it was accepted there because it came out of the Soviet Union, not from a rival US group.
The Tokamak was a great advance, and it has been the center of the US, European and Japanese programs for the last four decades. In spite of its improvement it is fatally flawed for a number of engineering reasons. Note that the last three Tokamak projects have been scrapped as unworkable in the design stage, the latest being the ITER project mentioned in the Fresno Bee article ).
The prime damage the Tokamak has done over the decades, besides eating billions of dollars, has been the suppression of research into alternative fusion technology. I can comment on this from two points of view. First I did some of the alternative research before we were de-funded. Second, I was later a Program Manager at the Department of Energy's Office of Fusion Energy for a year before I was let go as part of the massive cutback of the Fusion program.
During the 70's , after receiving my degree, I assisted Dr. Daniel Wells in his TRISOPS project at the University of Miami. The TRISOPS concept was that instead of trying to confine a hot plasma in a magnetic field (which is the mathematical equivalent of confining a ball of angry Jell-O in a cage of rubber bands), we should let the plasma form its own stable vortex structure and then compress it. An example of a stable vortex structure is a smoke ring. The equipment, by fusion standards, was simple. The lab was the size of a small suburban house. We were getting impressive results. See refs (1) at the bottom for a summary. Our funding was cut off because we were out of the mainstream. Also, Dan Wells, the principal investigator, was not good at the politics of science. I understand that the Wells' equipment has been recently moved to Lahnam MD where the experiment is being re-tried (by John Brandenberg under NASA funding - not DOE). I do not what results he has reached.
Another alternative project is being done by Paul Koloc (pmk@plasmak.com ), a plasma physicist formerly at the University of Maryland. He is looking into another stable plasma structure, ball lightning . Ball lightning has been witnessed for millennia, can sometimes last for minutes, and has killed people. Paul creates and measures ball lightning in a lab in a garage in his back yard ( no kidding ). The stable plasma structure lasts several milliseconds (It's is small so it has a short lifetime). He plans later to heat the plasma to fusion temperatures by compressing the atmosphere around the ball. His work is self-funded, with surplus equipment from the national labs, and some volunteer help from scientists there. He has presented several papers, the most recent at the 6th International Symposium on Ball Lightning. It has a small chance of working out, but at least as big a chance of the multi-hundred-million dollar DOE program. The abstracts are at http://home.wxs.nl/~icblsec/pg_abstracts.html under Koloc 1 and Koloc 2 You can write to Paul for the papers themselves.
I have described two alternative research schemes that I know of directly, I'm sure there are many others going on. Now that I have left physics to become an Internet geek, I no longer follow the field carefully. For I time I tracked Cold Fusion, until that fizzled out. As a final note: I do not believe that fusion energy of any sort will be able to compete economically with wind or solar power. There are many good comments and questions on fusion in this Slashdot thread that I will be glad to address on or of line if requested.
Ref (1) "High Temperature, High Density Plasma Production by Vortex Ring Compression" D. Wells (with others), Physical Review Letters, v 41 #3, p166, 1978. "The Interaction between Two Force Free Plasma Vortices in the TRISOPS III Machine" J. Davidson (with others), Physics of Fluids, v 22, p379, 1979.
Re:Going to look interesting from space.. (Score:2)
Your proposal would mean airconditioning our environments, e.g cities, parks etc, leaving everything else rather warm.
The good news is that this would still eliminate _most_ heat pollution. By far the largest sources of heat are cities (consuming electrical and fossil-fuel energy), and power plants (producing electrical energy at imperfect efficiency). Both of these can be cooled without *too* much additional expenditure (electricity and fossil fuels double in price due to taxes for the increased infrastructure needed).
Build this into the infrastructure in smaller population centers like towns, and you're left with highways and small villages as heat sources. Somewhere between 90% and 99% of heat production is accounted for, which dramatically reduces the environmental impact of heat pollution.
From space, the 1300 degree radiators would look like yellow-white glowing patches that show up even during the day. The 230 degree patches wouldn't show in the visible spectrum (they'd glow quite brightly in the intermediate IR spectrum, though).
Re:Military Technology != Public Technology (Score:2)
Oh that is such bullshit. Where do you get the statistic for this "military is 10 years ahead of public" nonsense?
Yeah, if they are so damn far ahead of the general public, what's up with this big move to NT powered military hardware [gcn.com]? Somebody better clue 'em in!
======
"Rex unto my cleeb, and thou shalt have everlasting blort." - Zorp 3:16
Requirements for fusion (Score:2)
You could indeed produce fusion by firing two particle beams at each other. The problem is that particle accelerators are very inefficient; you'd wind up putting in far more energy to accelerate the particles than you'd get back from fusion events. Particle beams are also very sparse; you might only get a handful of nuclei even hitting each other, out of all of the nuclei in each of the intersecting beams. Lastly, when two nuclei collide, most of the time they bounce off of each other. Only a direct hit produces fusion (or other interactions, for higher-energy accelerators).
You can eliminate the tenuousness problems by firing a single beam at a target made of lithium or frozen hydrogen, but the other two problems remain.
Now, the fundamental issue - the "temperature" of something _is_ just the average energy of all of the particles in the object/gas/whatever. By accelerating particles to energies sufficient to overcome electrostatic repulsion... you've increased the temperature, as that's what temperature is a measure of.
As an interesting bit of trivia, fusion produced by a particle beam striking a target _is_ used in some applications. Certain types of nuclear warhead, for instance, use this type of device to produce a precisely-timed neutron pulse used to trigger fission. However, this is still done at a horrible energy cost (the object is to produce neutrons, not to get out more energy than they put in).
COOL! (Score:2)
I light a splint, start the microwave, and watch for a few seconds. Nothing's happening, I'm skeptical and then (wait for it...)
BZOWN! BZOIN!
Two yellow flashes of...something. My adrenal glands kick into overdrive and I reflexively hit the Clear button. The splint still burns in the darkness of the microwave, so I nuke it again. Same thing! Too cool.
I'm not sure I buy the explanation that I'm seeing a plasma discharge - got a scientific reference on this?
Re:Just you wait until ICF beats everyone (Score:2)
Re:Underground bombs / using trapped heat (Score:2)
> that get a *very* high portion of their yield
> from fusion, as opposed to fission, there
> probably wouldn't be that much radiation to
> worry about in the first place.
It turns out that there would be.
Fusion reactions, like most other nuclear reactions, produce copious quantities of neutron radiation. This would make anything nearby (in this case, the surrounding rock) radioactive by transmutation.
The main benefit of fusion power isn't that it "doesn't produce radiation" - it does. It's that fuel is virtually unlimited. You also don't produce any _primary_ waste - spent fuel rods and the like. Just secondary waste (reactor structures made radioactive by transmutation).
Uninformed fears of nanotechnology. (Score:2)
I just love these lines of reasoning. Nanorobots and genetically-engineered bacteria are two very different things. Get this straight.
There IS a consequence of irradiating nanobots. They crumble into silicon powder. Nothing more. No scary "mutation". Seriously, has the alpha-decay in the RAM in your computer caused your computer to gain evil sentience yet?
Oh, and mutation requires reproduction. Nanobots, in general, are NOT designed to reproduce. (self-replicating nanobots is a fairly stupid idea actually...) You will find that no matter how much radiation you throw at a single organism, the only thing you're really going to do to it is kill it. The offspring are generally where mutations happen. (this is not ENTIRELY true for bacteria though...)
Regardless, nanobots are just small robots. Jeeze.
Re: Fusion is a LOT more DANGEROUS than coal (Score:2)
You can bombard material with as much energy as you want
But when you carry out a reaction that gives off neutrons, such as in a breeder reactor, then the surrounding material will be bombarded with those neutrons. This is what causes the reactor itself to become radioactive. The reactor itself absorbs neutrons, and the otherwise-normal atoms that make up the surrounding material are changed into unstable isotopes, and break down. The result is that nearly anything that is bombarded with neutrons will itself become radioactive.
The "holy grail" of fusion would be to construct a reactor that fuses hydrogen into helium. This reaction does not give off neutrons, and would not turn the reactor radioactive. This is the theoretical promise of fusion. An ideal fusion reactor would use pure hydrogen as fuel, and emit pure, ordinary helium as a byproduct, along with energy.
Turns out that no one has been able to make a fusion reactor work with ordinary hydrogen, but it is possible to "cheat", and create a fusion reaction using deuterium or tritium. These are hydrogen atoms with either one or two extra neutrons. It's much easier to fuse deuterium then it is to fuse hydrogen, and even easier to fuse tritium, but the downside is that you get neutrons as a side-effect, so the reactor itself becomes radioactive
Even this is better then a fission reactor though, because the major waste product of a fission reactor is the used fuel rods. A "dirty" fusion reactor would not generate used fuel rods, but would still become a large, radioactive building over time.
As far as the massive heat released by fusion, this isn't an issue because a fusion reactor works on a tiny, tiny amount of hydrogen at any time.
A fusion reactor is basically a vacuum chamber, with a small amount of hydrogen floating around inside. The vacuum chamber is surrounded by an arrangement of electromagnets. When the electromagnets are turned on, the hydrogen is forced into an extremely thin ring. This is called magnetic compression. In theory, if the magnetic field can be made strong enough, the hydrogen atoms will be compressed together so tightly that they will fuse.
The only way to raise the hydrogen to fusion temperatures is to use a vanishingly small amount of hydrogen at any given time. This makes a fusion reactor safe against meltdown.
When a fission reactor overheats and malfunctions, the core -- all the fuel -- can melt together. When this happens, the nuclear reaction continues, uncontrolled, and the result is Three Mile Island.
If a fusion reactor were to become overheated, and malfunction, it would simply break down and stop.
If you were to try and explode a fusion reactor by dumping a lot of hydrogen into a running reactor, the excess hydrogen would quickly absorb the reaction heat, and the reaction would stop. If you were to try and overheat a fusion reactor, you would burst the vacuum chamber, air would rush in, and quench the reaction. In short, a fusion reactor is meltdown-proof, and explosion-proof.
However, the practical problems of building a fusion reactor were discovered in the 50s and have never been surmounted. The biggest problem is that you can compress the hydrogen into a thin ring, but the ring quickly becomes unstable and flies apart. No one has been able to solve the problem of keeping the fusion reaction going once it has started, hence no fusion reactors.
Fusion reactors do NOT have the dangers you describe, however.
Re:Practical approaches to solar. (Score:2)
The FAQ for alt.solar.photovoltaics: http://www.means.net/~mschwarz/solar-faq.html
I'm afraid that neither your response nor your faq address the concerns I was addressing in my post.
The issues that I was addressing were 1) cost of maintainence of space-based and ground-based solar power plants, and 2) cost effectiveness of space-based solar power plants.
The primary issues for 1) are durability and cost of replacement. Once upon a time, solar cells were fragile. As you point out, this has changed. However, a solar "shingle" is a lot more expensive than a sheet of aluminum the same size, and not significantly more durable. Reflectors are still considerably more cost-effective per unit area per unit lifetime than any _presently_practial_ type of photovoltaic panel. Thus, concentrators are cost-effective to use.
Note that I say "presently practical". I'll get back to this below.
Additionally, _presently_available_ solar panels have rather horrid efficiency - about 15% for the best mass-produced panels in real-world conditions, and less than that for many of them (source: a recent overview of photovoltaic technologies in (if I remember correctly) Scientific American). Heat plants, on the other hand, can have efficiencies substantially higher. This makes concentrator/heat plant systems more efficient than _present_ photovoltaics, for many classes of system.
Note that I'm again stressing "present". Photovoltaics is indeed a fascinating field that continues to advance. The arguments that I present may well be invalidated when lighter, cheaper, and more efficient panels are produced. I'll come back to this below. However, I am discussing plants that can be built with today's technology, or with technology that is likely to be in mass-production within the next few years.
The second problem that I was addressing was cost concerns for a solar power satellite.
Micrometeorites are very destructive. They only damage tiny areas per strike, but will get through most coatings on solar panels, even ruggedized ones. Thus, the lifetime of panels (time before enough of their area is destroyed to make them useless) doesn't vary much with their durability, except for panels that are prohibitively heavy (cost of putting the satellite up is directly proportional to weight).
The natural solution to this is to use thin panels. However, reflectors (aluminized mylar) can be made much thinner than _presently_practical_ photovoltaic panels. This again favours a concentrator scheme, like the one I described. Cost per unit area is reduced, and lifetime isn't too strongly affected (possibly even increased, _if_ reflectors function better when badly damaged than photovoltaic panels).
Note the "presently practical" again. There is a panel technology that would invalidate all of my arguments above:
Thin-film amorphous or polycrystalline panels on mylar.
Unfortunately, while this technology is being poked at in the lab, cell efficiencies are at present miserable, even compared to other photovoltaic technologies. This will almost certainly improve with research, but IMO thin-film panels aren't likely to be competitive for at least several years, and probably longer.
These are the justifications for my arguments above. I am trying to describe solar plants that could be built (in production scale) with _today's_ technology that would be practical.
Also, you either completely skipped over or dismissed out of hand my methanol suggestion. Nothing beats a flammable liquid for energy storage density (or very few practial things), and we already have most of the infrastructure to deal with it.
Powering a base on Mars. (Score:2)
> on mars. How else would they get all the power?
> AFAIK mars has quite a few clouds and storms
> regularly, so that would rule out solar as a
> sole source of power
AFAIK, weather on mars is mostly clear. That's why we get such nice views of the surface via telescopes. The atmosphere is much thinner than Earth's, which means that dense clouds would be difficult to produce. Also, Mars's ambient temperature is below the freezing point of water. Dust storms happen, but aren't terribly frequent in most locations AFAIK.
Solar power would work fine most of the time, and power storage in batteries or fuel cells would be adequate during the occasional dust storms.
Re:Military Technology != Public Technology (Score:2)
I did. *ducking*
;-)
Even fission's CLEANER and cheaper than coal (Score:2)
Whether this goes up the stack directly into the atmosphere or accumulates in filters to make those filters a radioactive disposal issue, has not been made clear - but either way, how many tonnes of waste does a typical nuke produce every year?
Bear in mind that this is just the Uranium - stuff like Radium is released by the mining activities as well as by burning, and there's no figures for that.
And cheaper - how much cheaper is it going to be to NOT have to deal with the problems caused by the pollution, strip mining etc necessary to support a coal-fired plant? Not to mention side issues like the greater number of industrial deaths, the larger transport infrastructure, loss to industry of a greater number of workers through their dedication to the task, and so on.
Re:So they're getting closer... (Score:2)
Actually the reason we have radioactive waste was because the government(s) wanted a plentiful source of weapons grade material. If we had designed clean reactors in chain the amount of radio active waste would be much smaller. Though this would still only be a stop gap measure maybe 300-1000 years. Likely we will have to use more non-fossil fuel sources before we have fusion, actually the more the better likely at this point. (Global warming, need lubricants, etc.)
Not yet (Score:2)
So basically everyday, usable fusion is about ten years away.
Nothing new there.
I shouldn't be cynical. There hasn't been an innovative research project in the history of the universe (afaik) that hasn't taken years with a steady stream of mishaps. And the great thing about science is that bad results provide data as well as good ones.
But I still think we'll have a base on Mars before we see workable fusion.
This approach has had serious problems. (Score:3)
> article seems like the only way to go right now.
> Once they lick the symmetricity problem -
> possibly by setting up some positive feedback in
> the plasma to keep the reaction shape spherical
> in the crucial nanoseconds - there should be
> more progress.
It turns out that symmetry is extremely difficult to achieve.
This approach to fusion has been tried before - there is a whole class of fusion reactor that tries to induce fusion by running strong electric currents through a plasma (which is what this is - you just get your plasma by zapping a pellet).
From the first approximation, this looks very good - the magnetic fields created by the current flow act to compress the plasma, bringing it closer to satisfying the Lawson criterion. The problem is that variations in the current and in the density of the plasma/pellet cause assymetries, which tend to magnify themselves (the electric and magnetic effects of turbulence cause more turbulence). Because of the way that plasma behaves, there is no magical way to elminate this.
All fusion approaches encounter this problem. One approach to solutions - the one that it looks like they're using here - is brute force. It takes more time for turbulence to muck up a larger volume of plasma, which means that a larger device can come closer to satisfying the Lawson criterion. Also, dumping more energy into the plasma can help; fusion in conventional reactors occurs only among the hottest particles at the tail-end of the temperature distribution. Greater average energy means more particles of sufficient energy to cause fusion.
A second approach is to modify the design of the reactor to either reduce turbulence or to be less sensitive to turbulence. For magnetic confinement reactors, a lot of study has gone into different field geometries that stifle certain types of turbulence. For electrical discharge reactors - like the one described in the article - different electrode geometries have been tried. However, in the case of electrical reactors, this hasn't been enough to match the capabilities of magnetic confinement and inertial confinement (laser) fusion.
A hybrid reactor was recently built that used an electrical discharge to produce a hot plasma that was used as an X-ray source, which in turn was used to heat a fuel pellet in a chamber that reflected X-rays. This proved to be a very promising approach; for details, check back issues of (I think) Scientific American. This does not appear to be the approach described in this article, however.
Laser fusion's main problems aren't turbulence, which is why I haven't mentioned it much in this response.
Re:Military Technology != Public Technology (Score:2)
Muon-catalyzed fusion (Score:2)
> produce fusion is at extremely high
> temperatures. No one has suggested a meachanism
> (that works!) that would allow otherwise,
> possibly no one ever will.
Actually, muon-catalyzed fusion works at much lower temperatures (something like 800 degrees in the test rigs I heard about).
This is completely different from "cold" fusion. Completely different principles, well-understood, and well-tested.
The idea is that if you displace an electron in a hydrogen _molecule_ with a muon (its heavier cousin), the molecule will suddenly become much smaller, because the wavelength of a muon is much smaller than the wavelength of an electron. The hydrogen nuclei are now close enough to have a significant probability of fusion by tunnelling.
The problem with this is that muons are energy-expensive to produce, and don't stick around for very long (they decay into an electron, a muon neutrino, and an electron antineutrino). The energy released by the fusion reactions that the muons catalyze has so far been far, far less than the energy required to produce the muons in the first place.
Re:Military Technology != Public Technology (Score:3)
The military has thousands of fusion devices, mounted at the top of ICBMs.
The corrolary(sp?) is that the military never declassifies something until it has developed a countermeasure for it.
As Robert A. Heinlein said, the only defense against a nuclear bomb is not to be there when it goes off.
Re:Military Technology != Public Technology (Score:2)
The Earth is not heated by nuclear fission. It is heated by the natural radioactive decay of various radioisotopes that are part of the mantle (and maybe the core) material. The main elements are U, Th, and K.
Nifty bit of trivia: It's worth noting that there is evidence of an ancient, natural fission reactor that fired up spontaneously in the Oklo area of west Africa. This happened some 3 billion year ago, thanks to a rich bed of Uranium ore and the right combination of ground soil and water. In fact there are some 14 known reactor sites. Here's a link about the last one being mined:
http://www.apnet.com/inscight/05131997/graphb.htm [apnet.com]
General info about Oklo: http://www.nuc.umr.edu/~ans/oklo.html [umr.edu]
The natural reactors depleted the amount of U235 present in the ore and left behind long lived fission products.
Interestingly, neither the fission products nor the plutonium bred from the ore's U238 had migrated from the original reactor sites, despite having had billions of years in which to travel, plus plenty of ground water during a good part of that time.
Anyway, while the Oklo area would have been slightly hotter locally, it could not have put out enough power to alter the global heat balance to any great extent.
Fusion physics is public domain; technology, not. (Score:2)
- The most powerful nuclear devices yet invented are fusion-based; they get the majority of their energy by assembling atoms of helium from isotopes of hydrogen.
- All nuclear bombs have uranium or plutonium in them. "Atom" (fission) bombs go no further, while "hydrogen" (fusion) bombs use the energy from the fission reaction to initiate a fusion reaction.
- Fission bombs are pretty easy to make, if you have highly-enriched uranium. All you need is to make a sub-critical mass with a slug missing from the middle, such that the mass is prompt-supercritical when the slug is added. You fire the slug into it with what amounts to a zip gun, and it goes boom. This is how the "Little Boy" bomb which was dropped on Nagasaki worked.
- Plutonium is much touchier stuff, and requires an implosion design (collapse of a spherical shell of fissionable material to form a supercritical mass) to get things to work well. Implosion designs require precise timing of the explosive charges which do the work of assembling the mass. The "Fat Man" bomb that was dropped on Hiroshima was an implosion device.
- Making a hydrogen bomb not only requires you to get a healthy fission reaction going, you have to somehow couple the energy (and a bunch of the neutrons) to a mass of lithium deuteride. Li-6 captures neutrons and forms helium-4 and tritium. The tritium can then fuse with the deuterium, forming helium-4, a very high-energy neutron, and about 18 million electron-volts of excess energy overall. Unlike a fission bomb, you don't have to worry about exceeding any "critical mass" threshold so you can make a fusion bomb just about as big as you like... once you have figured out how to do it at all.
Note, the fusion energy available from a molecule of lithium deuteride is about 18 MeV, and it has a molecular mass of about 8. The fission energy from an atom of U-235 is only 191 MeV, and it is almost 30 times heavier. Fusion has a lot more punch for the mass.--
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Fuzzy on a few points here... (Score:2)
> vacuum, then not as much heat is required to
> sustain the reaction as stated in the article.
Um, not quite.
It takes a very hefty amount of energy to heat the plasma to the required temperatures - about 1.0e8 degrees centigrade. At those temperatures, plasma cools quite quickly by radiative emission, regardless of whether it's in vacuum or not. This is one of the reasons that the reaction only lasts nanoseconds.
> Only about 100,000C is needed before the atoms
> can become ionized and begin to transfer energy.
Um, not quite.
The plasma doesn't just have to be plasma - it has to be plasma of high enough energy that the nuclei can overcome their mutual repulsion. Hence, the 1.0e8 degrees figure for most terrestrial reactors (stars use lower temperatures, higher densities, and longer confinement time).
> At this stage things get a little fuzzy, because
> some of the normal laws of physics don't work
> because the atoms are in a plasma state.
Actually, they work just fine. You're just dealing with a conducting gas.
> The good news is the are electrically charged
> and can be controlled by magnets(as mentioned in
> the article). This should help keep the reaction
> in one spot.
Correct. This is the principle behind magnetic confinement fusion.
Other approaches exist. Both the approach described in the article and laser fusion rely on inertial confinement instead - the particle is suddenly compressed, and by the time it disperses the reaction has finished.
For more information on fusion and many other interesting things, browse your local university's bookstore for physics texts. My personal favourite is "Physics for Scientists and Engineers, Extended Version", bt Paul A. Tipler.
In other words... (Score:2)
Exactly. Usable fusion has been about ten years away for the past forty.
Who was it that said, "Atomic power will be too cheap to meter?"
Re:Military Technology != Public Technology (Score:2)
Good to see flaming carrot posting on slashdot.
"Cheap, clean power will save the environment" NOT (Score:4)
The bottomline, IMHO, is that the sooner we have fusion - or another cheap, environmentally clean energy source, the less likely we are to destroy the rest of this planet and hence ourselves.
Yeah, right. And computers will lead to a paperless office hence saving the rainforest.
Cheap power will only lead to increased production capacity and will intensify the demand for raw materials.
People will be able to live in places where it is currently uneconimical to live. The use of said power will also generate a lot of waste heat.
The government will build huge roving automatons with fusion reactors in their bellies to control the population.
All life will be consumed by nanobots which will turn the entire surface of the planet into grey goo which resembles an as yet uninvented flavor of McDonald's shake.
Or something.
Nuclear Fusion Journal (Score:2)
--
Paul Gillingwater
Re:Military Technology != Public Technology (Score:2)
I shouldn't have to do more stuff simply because I've earned an automatic +1 score. I don't care about my karma. I think it's laughable that it's gotten as high as it has. But I shouldn't be penalized for having an on-the-average positive posting history. "The rules" used to be that if you have such a bonus, you get the bonus, no matter what.
I'm very much so playing within the rules. If I weren't, I'd be posting random insults as an AC. Oh wait, that's a certain AC's job. Never mind.
---
"'Is not a quine' is not a quine" is a quine.
So they're getting closer... (Score:3)
Wasn't Nuclear energy supposed to be that? Until we realized there was no place to put the radioactive waste generated.
They are working on this new technology, and while there are still some bugs to work out, I believe human inginuity will prevail, and we will see this technology working within my lifetime (before 2050).
I predict however that there will be unforseen problems, such as disposal of waste... weird kind of pollution generated by the explosions... things that can't be accounted for until a working model is built. Of course when the working model is built, all will bow down before the solution to all the world's energy problems, and nobody will think to listen to anyone with a negative word to say.
Just a thought... might not happen.
Weren't cars, phones, computers, _____ (fill in the blank) supposed to solve all our problems?
I don't think the worlds problems will be solved until there is a significant change in the organization of authority and government in the world. That probably *won't* happen in my lifetime.
Re:Military Technology != Public Technology (Score:2)
---
"'Is not a quine' is not a quine" is a quine.
Mea culpa (Score:2)
BTW, I mis-stated a number above. The fission energy of U-235 (under thermal neutron bombardment) is 194 MeV. U-233 is 191 MeV, Pu-239 is 201 MeV according to the CRC.
--
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Re:Fusion ain't clean ... (Score:2)
Re:Fusion ain't clean ... (Score:2)
Fission goes the other way. It's what takes large isotopes such as U238 and splits them apart into smaller atoms, which then spew off the extra neutrons.
Hey, here's an idea... have a fission reactor surrounded by Hydrogen-rich water. The excess neutrons convert the free hydrogen in the water into deuterium. Then you use the deuterium as fusionable mass. :) (I know, that's impractical on many stages, but it was a silly thought.)
But anyway, if you ever get confused about the direction of the atomic reactions, just remember: the sun is a mass of incandescent gas, a gigantic nuclear furnace, where hydrogen becomes helium at a temperature of millions of degrees. (This helps because helium has a higher atomic number than hydrogen, indicating that the atoms fuse together - hence fusion - rather than break (fissure) apart.)
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"'Is not a quine' is not a quine" is a quine.
A demostration from home - why this isn't easy. (Score:4)
Take a wooden splint, like one of those things used to stir coffee.
Stick it into something that will stand it up, say a pencil eraser, or a piece of bread.
Light the tip and stick it into the microwave. Nuke for 1 minute.
Voila. what you will witness is a plasma being formed at the flame. A redox reaction is occuring, with atmospheric oxygen oxidizing the wood. The microwave energy is somehow disrupting the flow of the ionized particles (electrons and all) and forming your plasma.
Now, generating this plasma is one thing (Try it! It doesn't damage the microwave) but controlling this plamsa is a totally different story. Think you can accelerate this plasma down a tube and aim it at some target, a la plasma rifle from Quake? If you can do that, gimme a call 8-)
This demo illustrates the precise nature of fusion research. While generating a fusion reaction isn't difficult, it's controlling the reaction that's being a pain in the arse...
-=- SiKnight
Re:Fusion ain't clean ... (Score:2)
Of cource, I may be making that up or something weird - I really haven't had enough sleep.
Re:Military Technology != Public Technology (Score:2)
Yes, I've heard of the hydrogen bomb. I was under the impression that most nuclear bombs are Uranium (and fission) based, as they have much more destructive power than H-bombs. Yes, I know, H-bombs were what ended WW2. Yes, I was using a sweeping generalization, and wasn't thinking completely straight. My bad, and no need to be insulting.
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"'Is not a quine' is not a quine" is a quine.
Re:WRONG! (Score:2)
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"'Is not a quine' is not a quine" is a quine.
Re:Military Technology != Public Technology (Score:3)
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"'Is not a quine' is not a quine" is a quine.
Re:Fusion ain't clean ... (Score:3)
As for making deuterium with fission reactors, most fission reactors are surrounded by water, but hydrogen has such a low neutron capture cross section you don't get any significant quantity of deuterium (If hydrogen did have a large capture cross section, you wouldn't want to surround a reactor with it because it would soak up all the neutrons, upon which the fission chain reaction depends). I work at a research reactor; it's a 250kW reactor sitting at the bottom of a 25ft deep pool of water. That water's been there for 30 years (reactor was installed in 1968), and it's still just regular old water
Re:Military Technology != Public Technology (Score:4)
But things don't stop there. There are fission-fusion-fission bombs that start out like a fission-fusion bomb, but the fusion reaction is used to create another fission reaction in a sheath of material on the outside of the bomb. Typically, this sheath is made of common U-238, as opposed to the U-235 that is used in uranium based fission bombs and nuclear reactors. U-238 actually has more destructive potential than U-235, but it wasn't used in earlier bombs because it's simply impossible to start a fission reaction in it under normal circumstances. That's why you need that fusion trigger. Fission-fusion-fission bombs are basically the most destructive weapons in existence, and unlike fission-fusion bombs they result in a lot of fallout as well. They are nasty things.
Here's an interesting fact: a lot of modern warheads can be converted between fission-fusion and fission-fusion-fission quite easily. Since the U-238 is typically a sheath surrounding the bomb it can be replaced with a simple lead sheath quite easily. It's nice to have versitile nuclear weapons, isn't it. If you want to blow something up, use the lead sheath. If you want to REALLY blow something up and have no intention of taking over the land you blew up anytime in the near future, use the U-238 sheath.
Want to hear about some even nastier weapons? Sometimes called "hemisphere bombs", cobalt-salted nuclear weapons have the ability to, well, kill everything on a hemisphere. They don't do this with a really big explosion, but rather with intentional and very lethal fallout. If I remember correctly, they use a sheath of cobalt-59. The cobalt-59 is changed to cobalt-60 when the bomb blows up. Cobalt-60 is special because it is very radioactive with a half-life perfect for totally annihalating your enemy. It's half-life is 5 years, which is short enough to be fatal if you are simply exposed to it, rather than just causing cancer which might shorten your life-span in the long-run, yet long enough to make waiting it out in some underground bunker rather impractical. Your cobalt-salted bomb is detonated in the upper atmosphere to spead the cobalt-60 all over your enemy, at which point they are as good as dead.
In case any of you find my fascination with nuclear weapons a little sick, I'll tell you in advance: I don't care. Nukes are fun!
Re:Military Technology != Public Technology (Score:2)
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"'Is not a quine' is not a quine" is a quine.
Re:Just out of curiosity... (Score:2)
Re:Military Technology != Public Technology (Score:3)
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"'Is not a quine' is not a quine" is a quine.
Re:Fusion ain't clean ... (Score:2)
As far as helium balloons, that was what I was trying to get at with the "boon to the balloon animal industry" comment. (Yes, I know you don't use helium in balloon animals.) Isn't helium generally 'mined' from areas with high levels of alpha particles anyway? If my (obviously flaky) memory serves, helium was discovered around the same areas that radium was, correct?
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"'Is not a quine' is not a quine" is a quine.
The Fusion Science and Technology Incentives Act (Score:2)
Back in the early 90's, I got together with a bunch of the fusion technologists who were pursuing alternative technologies. We drew up some legislative language to better serve innovation in fusion energy. Bob Bussard took it upon himself to send that legislative proposal to every Senator and Representative in the US Congress. I figured if it was good enough for Bob it might be good enough for Slashdot fusion-fans 'lo these many years later
THE FUSION SCIENCE AND TECHNOLOGY INCENTIVES ACTSec 1. Congressional findings and declaration of policy
(a) The Congress hereby finds that --
(1) the United States is founded on the nobility of the creative act,
(2) this respect is enshrined in the Constitutional provision for patents of invention.
(2) in theory, the fusion of light atomic nuclei can provide the basis for such energy sources;
(3) the concept of fusion energy based on the confinement of high temperature plasmas has been the subject of ongoing government-funded research and development for over three decades;
(4) during these decades our understanding of high temperature plasmas has progressed to the point that, with appropriate government incentives, the tradition of diversity and risk management in our free enterprise system can expand the frontiers of fusion energy technology at a rate far greater and at a cost far lower than centrally planned programs funded by the government alone;
(5) progress in fusion energy systems is currently limited by the lack of a diversity in technical approaches being explored;
(6) to ensure the timely commercialization of fusion energy systems, the United States Government must create an environment in which the inherent commercial rewards of fusion energy technology are leveraged by supplementary Federal funds so as to motivate many diverse inventors and investors in the private sector who will freely and rapidly develop the frontiers of fusion energy technology;
(7) it is vital that the Federal Government continue its direct financial support for scientific research in the physics of high temperature plasmas as this creates fundamental new knowledge of immense value which cannot be patented or reasonably treated as intellectual property;
(8) it is a proper role for the Federal Government to stimulate accelerated commercial investment in the development and demonstration of fusion energy technologies; and
(9) the stimulation of commercial investment in the development of fusion technology can be accelerated through the award of cash prizes to entrepreneurs achieving significant technical milestones and the granting of funds matching those put at risk by private investors.
(b) It is therefore declared to be the policy of the United States and the purpose of this chapter to stimulate commercial investment in the development and demonstration of fusion energy systems and continued scientific research into the physics of high temperature plasmas. Further, it is declared to be the policy of the United States and the purpose of this chapter that the objectives of such a program shall be --
(1) to promote an orderly transition from the current research and development program to a new one in which the private sector capitalizes and manages risks inherent in the development and demonstration of fusion energy technologies under the disciplined diversity of free enterprise while the government continues to directly fund plasma physics research;
(2) to stimulate private sector investment in fusion energy technology by awarding substantial prizes for significant technical achievement and matching private investment with public grants;
(3) to, over time, systematically remove public support for private investment in fusion energy development and demonstration commensurate with the removal of barriers to commercial deployment of fusion energy systems;
(4) to continue international cooperation in plasma science for the benefit of all nations;
(5) to give preferential treatment to aneutronic fusion cycles;
(6) to give preferential treatement to fusion cycles that make use of readily available fuels;
(7) to stimulate the commercial deployment of competitive fusion energy sources; and
(8) to demonstrate that United States science in partnership with commercially financed technology development and operation continues the tradition of world leadership in science and technology.
Sec. 9302. Definitions
For the purposes of this chapter --
(1) "fusion" means a process whereby two light nuclei, such as deuterium and tritium, collide, forming a compound nucleus, which subsequently separates into constituents which are different from the original colliding nuclei, and which carry away the accompanying energy release;
(2) "energy system" means a facility designed to utilize energy released in the fusion process for the generation of electricity and the production of hydrogen or other fuels;
(3) "Secretary" means Secretary of Energy.
(4) "scientific research" means activities that discover knowledge about natural phenomena, which, under existing statute, cannot be held as intellectual property via patent;
(5) "scientific knowledge" means knowledge acquired or discovered through scientific research;
(6) "development" means the acquisition of knowledge or reduction to practice of an invention which does not exist in nature and which has some practical value or which has value as intellectual property under patent law or other statutes;
(7) "engineering break-even" means the production, by a fusion energy device, of a fusion burn which consumes at least 5% of the confined fusion fuel and which produces at least twice the energy consumed by the fusion energy device during the burn;
(8) "commercial break-even" means the self-sustaining operation of a fusion energy device by feeding its power output back to its power input without the need for any outside input except its fuel;
(9) "commonly available" is any fuel whose dollar (1992) per ounce commercial price multiplied by the number of tons of plant and equipment required to burn it per million watts sustained power production is a quantity less than 10,000 dollar-tons per megawatt-ounce;
(10) "energetically aneutronic" means any fuel which, when burned in a fusion energy system, produces neutron radiation carrying away less than 10% of the produced energy;
(11) "environmentally aneutronic" means any fuel which, when burned in a fusion energy system, produces neutron radiation carrying away less than 1% of the produced energy;
Sec. 9303. Program activities
(a) Scientific research in areas where lack of knowledge limits the development of fusion energy systems;(1) The Secretary shall periodically survey commercial participants in fusion energy technology development or potential investors in same, to determine critical gaps in scientific knowledge;
(2) The Secretary shall initiate scientific research emphasizing gaps in scientific knowledge as determined from the survey of commercial developers and investors;
(3) The Secretary shall fully disclose to the public all discoveries made in the course of government funded research under this program;
(4) The Secretary shall, on an annual basis, convene an independent panel, no member of which may have received Federal funds for fusion-related research or development in the last 5 years nor served on the panel in the last 5 years, to review scientific research activities to ensure Federal plasma physics funds are not being used for patentable fusion technology development purposes instead of unpatentable scientific research into plasma physics;
(5) If the independent review panel determines an activity is development rather than research, the Federal funds used for such development must be repaid to the United States Treasury to reduce the federal debt;
(6) Physicists receiving income from government-funded fusion energy research or development prior to the enactment of this legislation are to be awarded an annual grant for the next 5 years equal to their average annual income derived from Federally-funded fusion energy programs over the last 5 years, up to a limit of $60,000(1992) per year, the purpose of which is to recognize their committment and contribution to the field and to aid in their transition to the new funding environment; and
(7) Commercial Fusion Enterprises, as defined in 9303.b.1 may enjoin the government from continuing to directly fund scientific research in plasma physics which they believe to be in competition with their efforts to develop fusion technology.
(b) The stimulation of commercial investment in fusion technology development;(1) Any private, for profit, business owned or controlled by United States persons which is primarily engaged in the development of fusion technology qualifies as a Commercial Fusion Enterprise.
(2) Every U.S. citizen possessing a patent for a fusion energy system is to be provided with full reimbursement of all tax-deductible expenses incurred the pursuit of their patent, up to a maximum of $100,000; the purpose of which is to assist the inventor the expense of pursuing private capital of further development of the patented technology, under the incentives of the current Act.
(3) Any facility owned or controlled by United States persons generally used by Commercial Fusion Enterprises and primarily used for the development of fusion technology qualifies as a Commercial Fusion Center and also as a Commercial Fusion Enterprise.
(4) Commercial Fusion Enterprises shall receive matching funds from the government for each private investment they make toward the development of fusion technology.
(5) Funds provided by the government, as well as the private funds they match, shall be used to develop fusion energy technology. Failure to use such funds to develop fusion energy technology shall render the Commercial Fusion Enterprise liable for such damages and criminal penalties as are warranted under the existing statutes against securities fraud currently enforced by the Securities and Exchange Commission.
(6) The first Commercial Fusion Enterprise to demonstrate engineering break-even shall receive a $100,000,000 prize from the Fusion Energy Trust Fund, which is hereby established, and whose contents are to be invested in 30 year Treasury instruments and whose disbursements are to be administered by the National Academy of Engineering.
(7) The first Commercial Fusion Enterprise to demonstrate engineering break-even using an cycle burning an energetically aneutronic fuel shall receive a $100,000,000 prize from the fusion Energy Trust Fund.
(8) The first Commercial Fusion Enterprise to demonstrate engineering break-even using an cycle burning an environmentally aneutronic fuel shall receive a $100,000,000 prize from the fusion Energy Trust Fund.
(9) The first Commercial Fusion Enterprise to demonstrate engineering break-even using using a cycle burning a commonly available energetically aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(10) The first Commercial Fusion Enterprise to demonstrate engineering break-even using using a cycle burning a commonly available environmentally aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(11) The first Commercial Fusion Enterprise to demonstrate commercial break-even shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(12) The first Commercial Fusion Enterprise to demonstrate commercial break-even based on a fusion cycle burning an energetically aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(13) The first Commercial Fusion Enterprise to demonstrate commercial break-even based on a fusion cycle burning an environmentally aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(14) The first Commercial Fusion Enterprise to demonstrate commercial break-even using a cycle burning a commonly available energetically aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(15) The first Commercial Fusion Enterprise to demonstrate commercial break-even using a cycle burning a commonly available environmentally aneutronic fuel shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(16) The first Commercial Fusion Enterprise to demonstrate engineering break-even at power densities above 1 million watts per ton of equipment shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(17) The first Commercial Fusion Enterprise to demonstrate commercial break-even at power densities above 1 million watts per ton of equipment shall receive a $100,000,000 prize from the Fusion Energy Trust Fund.
(18) Interest income on the Fusion Energy Trust Fund shall be used to increase the value of all prizes according to the Producer Price Index. Excess income shall be returned to the United States Treasury used to reduce the national debt.
(19) One year after this bill becomes law, The Secretary shall hold a series of 10 monthly publicly advertised auctions. At each auction 10 kilograms of Helium-3 will be sold to the highest bidder. The winning bidder must:
a) be a Commercial Fusion Enterprise.
b) not have already won a previous auction.
c) not have cross-ownership with any other Commercial Fusion Enterprise that has already won at a previous auction.
d) have a board of directors and officers that do not overlap with the board of directors and officers of any other Commercial Fusion Enterprise that has already won at a previous auction and;
e) not have more than 10% of its ownership in common with any other Commercial Fusion Enterprise that has already won at a previous auction.
20) The Secretary shall make 100 acres of the Nevada nuclear test range available to Commercial Fusion Enterprises. This land shall:
a) cost no more than $1000 per month to lease per acre, including all user fees.
b) be remote enough that the instantaneous release of 1 gram of tritium gas per month will pose no significant health risk to those outside the test range.
c) be located on land suitable for construction.
d) have paved access to the center of the 100 acre area.
Sec. 9304 International cooperation;
Scientific research, as defined specifically in this act, being of a limited and nonproprietary nature, shall be conducted in a spirit of academic freedom and openness wherein scientists shall freely cooperate and communicate with other scientists without regard to national boundries. It is the intent of Congress that the State Department take action to facilitate the free international exchange of such purely scientific information and work.
Sec. 9305. Dissemination of information
(a) The Secretary shall take all necessary steps to assure all scientific knowledge relevant to fusion is made readily available to interested United States persons: Provided, however, that upon a showing to the Secretary by any person that any information or portion thereof provided to the Secretary directly or indirectly from such person would, if made public, divulge (1) trade secrets or (2) other proprietary information of such person, the Secretary shall not disclose such information and disclosure thereof shall be punishable under section 1905 of Title 18.
(b) The Secretary shall maintain an aggressive program in the United States for the provision of public information and educaitonal materials to promote widespread knowledge of fusion among educational, community, business, environmental, labor, and governmental entities and the public at large.
Sec. 9306. Annual report
As a separate part of the annual report submitted pursuant to section 7321 of this title, the Secretary shall submit to Congress an annual report of activities pursuant to this chapter. Such report shall include --
(a) a list of recent scientific discoveries in plasma physics as funded under this chapter;
(b) a list of Commercial Fusion Enterprises, their levels of capitalization, Fusion Energy Trust Fund prize applications and Fusion Energy Trust Fund prize awards;
(c) an analysis of the progress made in commercializing fusion technology; and
(d) suggestions for improvements in the national fusion program, including recommendations for legislation.
Sec. 9307. Authorization of appropriations; contract authority
There is hereby authorized to be appropriated to the Secretary, for the fiscal year ending September 30, 1993, such sums as are provided in the annual authorization Act pursuant to section 7270 of this title.
Nothing environmentally clean about fusion. (Score:2)
To me, this looks like a last gasp effort by the old defense establishment to avoid obsolescence and irrelevance, and perhaps to squeeze out a bit more dual use research. I hope we won't waste more time or money on that kind of research.
We have an excellent fusion generator in the sky. It uses gravitational confinement and works at a safe distance. Research into how to take better advantage of it is likely to be more successful. We can make incremental progress without hoping for big breakthroughs. And with the expenditures and subsidies invested in the nuclear industry, we could easily establish a thriving solar and hydrogen-based energy infrastructure.
Re:That song! (Score:2)
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"'Is not a quine' is not a quine" is a quine.
Re:Military Technology != Public Technology (Score:2)
Er, no, you've got it backwards.
The bombs detonated over Japan by the USA in World War II were fission bombs. The one dropped on Hiroshima used fired a slug of uranium into a larger target of the same. The one dropped on Nagasaki used a hollow sphere of plutonium surrounded with explosives. When the explosive charge detonated, it forced the plutonium together. (Plutonium is more unstable then uranium, so they couldn't use the "gun" technique.) These are usually called atomic bombs, or A-bombs.
Modern ICBMs (Inter-Continental Ballistic Missiles) are usually tipped with fission-fusion warheads. They use a smaller fission reaction to initiate an uncontrolled hydrogen fusion reaction. The result is a much larger explosion then with fission alone. These are called "hydrogen bombs", or H-bombs.
Upsilon [slashdot.org] made a good comment [slashdot.org] with information on uranium sheath fusion bombs and cobalt bombs, which are essentially fusion bombs designed to spread more radioactive fallout.
Re:Not yet (Score:2)
Here is a better link for Mars Direct [nw.net]. I suggest that people concerned about how this actually works study up on the in-situ propellant production.
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Re:Military Technology != Public Technology (Score:2)
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"'Is not a quine' is not a quine" is a quine.