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More Evidence for Tabletop Fusion
heptapod writes "Researchers at Purdue University have statistically significant evidence that their tabletop fusion experiments were successful. Yiban Xu's experiment different from an earlier Oak Ridge experiment using a different and cheaper source of neutrons than Oak Ridge's pulse neutron generator. Surpassing break-even point still eludes the grasp of science."
Surpassing break even is easy, we did it decades ago... What we are missing is a really big boiler, to make it work.
Where's the nuclear powered car we were promised back in the 1950s?
OLPC Australia
"Surpassing break-even point still eludes the grasp of science."
hmmm does it?
- "Hear that?! The percolations are imminent! Cease your ingress!"
Will we get it before or after Duke Nukem Forever?
Statistical evidence of fusion at this level is indeed impressive; however, while fusion experiments such as this others remain below the break-even point, they shall yet be little more than a labtable source of neutrons. We await developments from the latest in the field.
Are they counting break-even as getting back more energy than needed to operate the ultrasound source ou they did count also the expense of producing the deuterated acetone and their expendable neutron source?
It reminds me of when people say hydrogen burning cars will solve all emition problems because they produce water. They don't count the emissions that may be needed to produce, compress and ship the hydrogen to the nearest gas station.
http://www.dieblinkenlights.com
"The process is analogous to stretching a slingshot from Earth to the nearest star, our sun, thereby building up a huge amount of energy when released," Taleyarkhan said. I sure hope their process can be done easier than their analogy!
Robert Bindler
A Computer Science student's views on technology.
First, it's table tennis, now it's table fusion. Next thing you know, they'll be waiting on tables at my local chinese restaurant. man, this internet thing is great.
So... that Mr. Fusion I ordered off of eBay will actually work?
#define CLUE 0
Been waiting around for somebody to come up with something really inovative in the Fusion field of study to shake things up a bit. Been beating the magnetically confined setup for decades and it's still a big if. ITER will pump multi-billions into something that still won't see a pay-off, even if they manage to get beyond break-even and maybe even see ignition. Laser pulse inerital confinement is way too power intesive as well. My big question is, can we extract any heat from the damn thing??? If we can't, so much for heating the water to spin the turbine and generator.
I expect to to be 2050 when we get fusion.
Well...at least that's when Sim City let me build one...
This is gonna kill the fondue pot industry ...
The Luddites were ahead of their time.
Hey, my coffee's getting cold.
Would you mind nuking it for me.
If further research into tabletop fusion results in decent efficiency, ITER may be obsolete before they finish building it.
Granted we are not yet to the prototype powerplant scale of ITER with these proof of concept sized devices, but the difficulty in controlling plasma with magnets is far greater than bombarding something with neutrons and letting it do the work itself.
XeoMage
"When it's time to railroad, you get railroads." Or however the saying goes.
This question is one I've been thinking about for a few years now due to an idea for an invention I've got (not cold fusion, though), plus some stories I know of. The most relevant one is an episode of Outer Limits (the series from the 90s, not the one from the 60s).
In the story, an expelled physics student detonates a small 'cold fusion bomb' in a campus clocktower as proof of the technology, then takes a physics class hostage with another device. He demands that the people who have tormented him in the past be brought to the courtyard and shot in front of him, or he'll detonate the more powerful device he's got with him.
While the military is trying to figure out what the hell it was that detonated (since they don't believe in a cold fusion bomb), the negotiator is trying to figure out what the deal is with the hostagetaker. It comes out that, among other things, he believes there's a reason we've not found any signals from other species. The cold fusion technology is so simple that anyone can make it. When a species gets advanced enough to realize how easy cold fusion is, he says it's inevitable that a species will destroy itself before it can get mature enough to handle its technology. The negotiator then says, well, tell us what led you to the idea, and we can try to steer science around that until we can mature enough to handle it. The guy thinks back to what started him on the path to cold fusion - a physics test with the question, "Demonstrate why cold fusion is impossible."
I'd say it's inevitable that we WILL have this technology. How simple it winds up being is unknown at this point, of course, but hopefully it'll be complex enough that not every nut in a garage can do it.
of Cold Fusion, a technology that promises clean power in future (and prevent wars over oil). Just wondering why governments are so indifferent to Cold Fusion.
hilarious
they did this in spiderman 2 at least 6 mo. ago
I think this has some potential for abuse. Do we want this power to get into the wrong hands?
That's the very question currently being asked at the Pentagon. Just what will our government due when a drop on productivity is caused by millions listening to music with an ever-lasting battery in their iPods?
Life is not for the lazy.
It reminds me of when people say hydrogen burning cars will solve all emition problems because they produce water. They don't count the emissions that may be needed to produce, compress and ship the hydrogen to the nearest gas station.
The trick with this one is in the may.
Maybe someday we'll find a technology that's clean-burning and energy-efficient to the point where oil is no longer the most cost-effective way to make energy. Say, maybe nuclear fusion. Or maybe oil will eventually get so expensive that other energy technologies start to look not so bad by comparison. But if we ever reach this point, because of the massive installed base and economies of scale of oil systems, especially the ones in cars, we and our economies will still be dependent on oil. So it won't matter that the newer technology is better, we'll keep using oil anyway. That's bad.
Hydrogen may at first be ultimately dependent on "dirty" oil and coal to make the hydrogen in the first place, but because it decouples energy production from energy use, in the long run it gives us the capacity to move on to better energy sources. It's like a nicotine patch, okay, it technically doesn't address the addiction but the thing is eventually you get to take the nicotine patch off.
On top of this, there are situations where if you can't eliminate emissions, moving the emissions is a desirable second best thing. Like, of course we're not making advances in our contribution to global CO2 levels if all these cars in the city burning oil are replaced with a bunch of cars burning hydrogen [PLUS] one huge smoke-belching oil-burning hydrogen plant. But, well, if the city is Los Angeles, and the city is basically one huge smog-trapping bowl surrounded by mountains, and the smoke-belching hydrogen plant is on the other side of the mountains, then never mind the global CO2 levels, you've still made Los Angeles a significantly more pleasant place to live.
Irritable, left-wing and possibly humorous bumper stickers and t-shirts
I wouldn't toss ITER aside before I get to at least read the journal article on a few of these desktop setups. I'd still like to see what pressure they're operating at, temperature ranges, D/T enrichment, reaction rate, bubble size, mcnp models (a vised geometric plot at the least), fluent models, etc. I just don't trust science magazine or a run of the mill newspaper to publish groundbreaking science that's on par for an engineer to read, since those cater to people without much knowledge of the engineering feat discussed in the article. But that's the nuclear field (or any engineering for that matter), we're supposed to be skeptical as hell until it's widely duplicated. If I can do it in my lab, then I'll believe it. Or at least see it in someone else's lab who built it from scratch from nothing but the other researcher's blueprints. And controlling plasma with magnets isn't too hard, in fact it's down to nearly an exact science where only a few unknowns remain, mainly the occurance of MARFE's, diverter material protection, and so forth. The largest problem lies with protecting the magnets from the 14-MeV neutron flux exiting the core. But still, I wouldn't toss aside ITER just yet. It's got some work to do, but it's a pretty sound model for a large scale fusion power plant.
Seems pretty easy to me:
Step One: Build a sonoluminescence apperatus using an ocilloscope, a sine generator, audio amplifier, piezo transducers and spherical flask. Details here: http://www.physik3.gwdg.de/~rgeisle/nld/sbsl-howto .html
Step Two: Build a neutron supply source, problalby most easily constructed is a farnsworth-type fusor: http://en.wikipedia.org/wiki/Fusor (makes a great science project too)
Step Three: Get some deuterium and dissolve it in acetone, place in your sonoluminescence apperatus and start tuning it to produce bubbles. Availible at your local scientific supply store.
Step Four: Build your own neutron detector and confirm the bubbles are producing fusion: http://home.earthlink.net/~jimlux/nuc/ncount.htm
Step Five: Become the envy of the neighbourhood as the only guy on your block with a nuclear fusion device in your garage! (to avoid police suspicion call it a magical glowing bubble maker)
Step 6: Profit!
However, as a geek, I know that the Dark Ages were as much caused by the change in the fuel economy from wood to coal as the retreat of the Roman Empire.
Likewise, I believe that the Great Depression was caused by the shift from a coal-based fuel econmy to an oil-based econmy.
Let's face it - General Motors, Exxon, the Edisons, and all thier suppliers, rely on the current fuel econmy. We can pretend that our economy is based on bricks of shiny yellow metal, but it's really based on BTUs.
A shift to what would, essentially, be a free energy economy (picture a non-polluting, low-maintenance power plant supplying your house or your block) would have a greater impact than a return of the Black Death.
The Third World is probably in a far better position to take advantage of a fusion/hydrogen economy than the US and Europe, as they don't have the existing oil-based infrastructure.
I welcome the change, but I hope that I don't have to live to see the fallout.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Focus Fusion tries an alternative approach...
Ok, let me ask this. Why is this on AScribe and not on Nature?
I won't belive it until it's published on a peer reviewed journal.
I am not a Physicist but in any energy producing technology the source of fuel is the bottleneck. For ex. the antimatter propellant which is highly effecient but creating the fuel source(positrons) is the problem. I smell something similar here but I might be wrong.
What does your Credit Report look like?
I accidently submitted a story that is dupe. How to withdraw the story or inform slashdot?
Reply fast before it appears.
Im an idiot and used the bold tag instead of break.
NJ Local Music Scene
...find that episode of Outer Limits on my favorite P2P client. Thanks! :-)
The problem, of course, is that just about any physicist can answer the question as to why cold fusion is probably impossible.
I can just imagine Steve Jobs announcing cold fusion during a Macworld keynote - the phrases, the graphs, oh my..
I agree that mainstream fusion work will be important and is probably the right track toward a practical fusion powerplant.
However, remember that Cathode Ray tubes were also once little more than a labtable source of tightly controlled electrons. New sources of materials often lead into practical applications not originally envisioned.
It is impossible to enjoy idling thoroughly unless one has plenty of work to do.
- Jerome Klapka Jerome
How would America cope if the Terrorists gained the power to generate electricity?
"I think this has some potential for abuse. Do we want this power to get into the wrong hands?"
/.ing and /. dupes it will at least be a day or two for mass terrorists to realize this exists :)
With
That's right folks, come on down to Crazy Harry's Particle Superstore. Electrons! Protons! We've got neutrons for half the price of our competition! Mention this ad and get 10% off your next order of quarks!
Coder's Stone: The programming language quick ref for iPad
Conceptually, this is one of those ideas that ought to work, but, when push comes to shove, more often seems to be a test of adherence to current orthodoxy rather than merit. Too often the reviewers seem to read the title in order to form their opinions rather than reading through the work and, if necessary, replicating the experiment. Eddington's response to Chandrasekar's work comes to mind.
------ The only greater hazard to your liberty than n politicians is n+1 politicians.
It's interesting that the original professor's experimental results were discredited by the methods he used to detect fusion. First he detected neutrons, but then there was controversy about whether he was detecting fusion neutrons or png neutrons. Then, when he changed certain things, and still detected neutrons... everyone questioned whether or not they were background neutrons or fusion neutrons. Basically, they wanted to see the moment of neutron detection coincide with the moment of light creation down to the nanosecond (I think).
Now, these guys are using other methods of detecting fusion by neutron energy levels, and tritium. I just hope that the levels they detected were WAY above the statistical normal amount of 2.5MeV neutrons and tritium in deuterized-acetone controls.
New sources of materials often lead into practical applications not originally envisioned.
This is so true. No-one making velcro thought it would be good for strippers. It took their wives to figure that one out.
"The two researchers used an identical "carbon copy" of the original test chamber designed by Taleyarkhan"
If memory serves, when the Taleyarkhan et al. originally published their results, hundreds of scientists tried to reproduce the experiment. (After all, sonoluminescence is a cheap experiment to set up) I think only one group got a positive result.
One of the criticisms of the original work was that the original experimental set up was a little dodgy. It was suggested (among other things) that Taleyarkhan was receiving false positive spikes though inductive pickup between the drive for the neutron generator and the detector.
Further, most of the work I've read on sonoluminescence indicates that the estimates of the temperature and pressure inside the imploding bubble are not as high as the numbers that require fusion. Sure, when work on sonoluminescence was young, there were lots of crazy ideas and claims flying about. But now, it is considered unlikely that the bubble could stay perfectly spherical during the collapse. Experimentally, it has been shown that the presence of gasses in the water dramatically affect the intensity of the produced light. (See work by Putterman) One theories actually rely on the gasses causing imperfections in the bubble wall as it collapses, allowing a high pressure jet of water to shoot from one side to the other, fracturing the opposite wall. (Prosperetti)
Another theory is that the the light observed during sonoluminescence is blackbody or bremsstrahlung radiation, because the sorts of pressure and temperature mentioned in this article would allow this (and the experimentally observed spectrum is pretty close to that predicted by these models) but you should also see other effects on the water afterward, like disassociation and experimentally, this has not (as far as I know) been observed (see Eberlain's papers)
"Honey! My plate just fused to the tabletop again!"
Desktop fusion? Laptop fusion cannot be far behind, and then PDA fusion....
Table-ized A.I.
We've got neutrons for half the price of our competition!
What?! There's already no charge for neutrons!
All employees must wash hands before seeking equitable relief.
Surpassing break-even? No problem! The physics are well understood, even. In fact, I see it happening every day (starting around 6am these days usually).
It DOES require inconvinient amounts of hydrogen, though....
And neutrons already are known as a major pollution. Whatever they hit, it becomes radioactive and more fragile. So all materials used in fusion devices like ITER will regularly have to be disposed as a radioactive waste.
Doing H2 or H3 or H3-HE, will give off gamma. HE-HE will not. In fact, it only gives off alpha (electrons), which allow for direct harvesting without heat issues. So if they have this working for deuterium, I wonder if it is possible to get Helium to fuse?
I prefer the "u" in honour as it seems to be missing these days.
Now I'm going to have to take Keanu Reeves movies seriously again.
However, as a geek, I know that the Dark Ages were as much caused by the change in the fuel economy from wood to coal as the retreat of the Roman Empire.
However, as a pastry chef, I know that the Krebs cycle causes metal fatigue in steel structural support beams.
However, as a ballerina, I know that the Pythagorean theorem causes the release of neutrons from radioactive material.
However, as a professor of French literature, I know that penicillin causes cost overruns in long-haul LTL shipping.
All employees must wash hands before seeking equitable relief.
So you're worried that this might lead to a technology that could devastate the earth? I guess you've never heard about Nuclear Weapons, some of which are in the hands of some not so wonderful people, such as Kim Jong Il of North Korea. Sorry bud, you're trying to close the barn door after the horse has already left, about 60 years to late I might add. On the other hand, if this were an easy way to make large amounts of U-238 and Plutonium then I might be worried.
If you accelerate a bunch of nuclei fast enough at a bunch of target nuclei, all sort of stuff tumbles out of the rubble, including free neutrons, positrons and other alphabet particles (alpha, beta, gamma, etc.) This has been done and done again for decades in various labs and facilities around the world. This is a low cost particle accelerator you can fire up in your garage. Cool, but not novel.
It is very cool to see researchers hacking atoms any way they can. Don't listen to the "experts". The people with names we remember didn't.
Lurking at the bottom of the gravity well, getting old
Whatever they hit, it becomes radioactive and more fragile.
An exaggeration. Hydrogen atoms, for example, merely become deuterium atoms, which are not radioactive.
Which is why neutron shielding tends to be made of things like lightweight polymers that contain lots of hydrogen atoms. (In the early days before modern plastics, they used paraffin wax.)
There are other materials that can happily absorb a neutron and go from one stable isotope to another.
-- Alastair
Just theorizing but it would be interesting to see if they did this experiment in an autoclave or something similar.
Good one - I almost spewed Coke across my nice shiny new white iBook.
You can get tabletop fusion with a TV high voltage supply, a glass bulb, some wire, and deuteriums gas. That's been known for decades and is used as a neutron source commercially. People build those things for science fairs. It's called the "Farnsworth Fusor" (I know, in light of Futurama it sounds like a joke, but the fictional character was named after the real one).
Why don't we all have flying cars, then? Because you can't get a net energy gain with the Farnsworth Fusor--it seems to be impossible in general to do so, the numbers just don't work out.
Of course, even if you do make it efficient, it's not exactly "clean energy": even with so-called aneutronic fusion, a few percent of the fusion reactions will generate neutrons, which, for realistic power generation, results in a neutron flux that causes the power generation to be quite dirty. Not as dirty as fission--disposal should be easier--but don't expect something harmless you can just run in your basement.
So, tabletop fusion isn't really anything impressive: there are probably lots of ways of getting fusion on your tabletop. The question is how you make it efficient enough to useful amounts of energy out of it. And cavitation seems no more promising there than inertial confinement in the Farnsworth Fusor. But maybe if enough people keep playing around with this, someone will get lucky and find something that works.
"I think this has some potential for abuse. Do we want this power to get into the wrong hands?"
Somehow I don't see a new way to make warm acetone, even along with a few neutrons, as being much of a threat.
Once the acetone boils (and probably before, I suspect cold acetone is required for sufficiently spherical bubbles) your reaction will stop. You may be able to use some fluid with a higher boiling point than acetone, but I can't think of any with a high enough boiling point to be useful that also contains much hydrogen.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
thats not the point, the point is that some bright kid sees it in a diffrent way when being asked to sovle it and then figures out how to do it simpley.
OK then, Just in case anyone else is as thick as me: Don't check the parents of these replies unless you want to spoil your pleasure in reading the latest Harry Potter.
From TFA:"...The new findings were detailed in a peer-reviewed paper appearing in the May issue of the journal Nuclear Engineering..."
So I guess you are right that it is very old news indeed.
This space is intentionally staring blankly at you
*sigh*
:P
Who the fuck cares..
Sigh I can't believe the slackjaws are all over this crap.
I've unfortunately read the first 4 books of the series (picked them up cheap in a
boxset when I was in Amerikka) out of curiousity and to determine why there was
so much hype over what is essentially the "Hardy Boys" of the millenium.
Honestly J.K. Rowling's writing is competant, but really has nothing whatsoever to
justify this hype.
I liken the Harry Potter series of books to Enid Blyton's kids books back in our day,
I guess the kids will go crazy and lap this shit up like they did Pokemon and whatever else they find on the sidwalk, but I really don't see why adults are reading this drivel, let alone getting all fanatical about it.
I guess anything that will make the unwashed masses actually read a book can't entirely
be a bad thing, that and the Catholics considering the series subversive is a plus
Your problem is with H2 made from hydrocarbons - so don't use them, fill the desert with solar cells and crack water, or better yet - make electricity and ship it to the H2 filling stations and crack the water there - I kn ow it's not economical now ... but hydrocabon prices are going up and solar cell prices and efficiencies are getting better all the time - one day those curves will collide and the deserts will 'bloom'
Hydrogen atoms, for example, merely become deuterium atoms, which are not radioactive.
Deuterium can cause health problems (it blocks bio processes like mitosis).
But with time, the same atom does get hit by several neutrons. Radioactivity is then bound to happen in the expensive materials of ITER.
So ITER will produce some expensive waste. Given ITER estimated raw price, those questions need clear answers and a good comparison with the costs of other renewable energy sources.
Focus fusion is nearly unknown, although it seems to be quite advanced. Slashdot should something about it.
This sig does not contain any SCO code.
Is it just me or does this sound suprisingly similar to the keanu reaves film, chain reaction
water + sound = cold fusion, but this time its hydrogen+sound+neutons = nuclear fission
¦^)= The Vengance Will Come =(^¦
RTFA:
Researchers have estimated that temperatures inside the imploding bubbles reach 10 million degrees Celsius and pressures comparable to 1,000 million earth atmospheres at sea level.
This is NOT cold fusion, this is sonofusion.
Iraq: war to save the U
There was a BBC Horizon documentary on this nuclear fusion sonoluminescence phenomenon that casts strong doubt on the validity of previous work conducted by this researcher. The acid test for the occurence of fusion is the release of a neutron at the exact instant that the flash of light from sonoluminescence occurs. The Horizon team used a detector that can record the neutron releases at the required instant in time. After recreating Taleyarkhan's experiment according to his published journal papers, results were disappointing. None of the neutrons that were detected occurred at the same instant of any of the sonoluminescence flashes. The extra neutrons were explained away as originating from the emitter used to generate bubbles, or from external sources. No doubt rivals will challenge the statistically significant tritium claim. Tritium does occur naturally in significant quantities in any mass of heavy water (deuterium oxide).
"The fates of nations" by Paul Colinvaux
--MarkusQ
Maybe even more interesting is that Taleyarkhan now works as a researcher in Purdue, where the "new" results are from, and both authors of the new paper, Yiban Xu and Adam Butt, are now members of his workgroup. If the topic wouldn't be so controversial one could say it's OK to join forces, but as everybody still waits for an independent confirmation of the original results, this causes at least some doubts about the new results.
Okay, what if this does pan out?
presume: "Cheap nuclear fusion" power plants generate electrical power for equivalent of 1 cent / KWh.
* Coal usage drops to drastically (still used in off-grid locations)
* Oil production drops drastically;
* Natural gas still produced as portable energy source;
* someone figures out electrical generation of methane or propane (electricity + carbon + water) and cars start using that instead of OPEC oil;
* OPEC countries have vast revenue drops, destabilize, and undergo drastic political change (read: civil war, followed by a stable form of government that we may/may not like);
* Global CO2 emissions drastically drop due to no power plant emissions, but cars still use CO2 producing methods;
* incentive to produce economical renewable energy sources (solar cells et al) drops to nil;
* aluminum gets lots, lots cheaper;
* battery technology gets a big boost in investment.
I'm sure there's more, any ideas? Disagree?
Unitarian Church: Freethinkers Congregate!
I find it odd that focusfusion.org asks for donations, never mentioning that a lot of this money will likely end in the patent holders pockets.. org%20patent
http://www.google.com/search?q=site%3Afocusfusion
So what would happen if you used deuterated acetone in a cavitaion device such as the hydrosonic pump? (see, http://www.hydrodynamics.com/product_pics.htm)
Non-peer reviewed studies show that two people pushing certain things together on top of a table may not generate neutrons, but they can generate considerable revenue for porn publishers.
one of taleryarkhan's experiments was published in science march 8th 2002, pg 1868. it was high profile, and under a lot of attack by science magazine's own editors.
the article review by becchetti on pg 1850 says that this expt by taleryarkhan showed correlation of bubble flashes and neutron detection.
while the set-up of the expt was a bit bewildering to me, i recall reading why there was a lot of attacks on this article. other people were claiming that the levels of the detected neutrons were below the levels emitted by neutron source they used- as wagdog writes. recall that the expt'al set-up _requires_ one to bombard the acetone with neutrons. maybe they were detecting their own neutrons.
eh, controversy exciting anyways.
Everything I see on this shows there doing the work under atmospheric pressure. I really think they need to move to very high pressures and check the fusion rates agianst pressure. Although sonolumnescence under extreme pressures is probably a big research area in general you would expect the liquid/phase to become more ordered resulting in higher collapse energys potentially very high somewhere in the phase diagram. In fact if I'm right then there is a very high probability that gas giant planets actually heat themselves via this sort of high pressure desktop fusion instead of simply heat from contraction. I bet with the wealth of organic/organometallic substances/mixutures and high pressure phases you can hit the perfect system. I googled around to see if anyone has measured neutron emission from gas giants and drew a blank. Does anyone know if its ever been measured ?
for those of you interested, after taleryakhan published a high profile experiment in Science magazine in 2002, another group at oak ridge published a counter-claim that with identical set-ups, they could not produce the correlated sonoluminescence and neutron detection.
URL: http://link.aps.org/abstract/PRL/v89/e104302
as usual, an experiment with negative results are rare, and potentially interesting.
You have dropped enough acronyms and jargon to make me assume that you know something more about the details of tokamaks than the average Slashdotter, so I have a couple of questions for you:
1) Why is it said to take "50 years" for fusion to be developed? Whats the freaking hangup? I learned a long time ago that if something is expected to take more than 5 years to develop, it means that the technology is so immature that we don't even know what we don't know (with a nod to Rummy for that one). Hence we don't really know if "50 years" is 10, 20 or 500 years. You can't seriously tell me it'll take 50 years to find a suitable diverter material, or to design a cooling system for the magnets. So what is the real problem?
2) What about hybrids? A small fusion reactor to act as a neutron source, irradiating a sub-critical fission blanket that would provide an energy gain factor of 50-100. That seems like it would work really well in the near term. Why not?
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
I may not be the GP, but I'll throw in my $.02 as a fusion science researcher. (I work on a magnetic confinement device myself.)
1) The running joke of fusion is that it's always 30-50 years away. This is more due to meager funding levels than anything else. At a talk by a PPPL scientist a few years back, it was mentioned that if one plots the price of oil and the amount allocated for fusion research versus year, they track rather nicely. (The 70's were a great time to be in the field!)
Why the meager funding? Fusion researchers kind of shot themselves in the foot in the late 50's and 60's, before much of the underlying plasma physics was well understood. TFTR (the Tokamak Fusion Test Reactor, built in the late 70's, ran through the 90's) turned up physics phenomena that were unexpected and needed to be understood. (That can still be said for many devices today, which are built to specifically analyze these phenomena.) When Nature deals you a bum hand, you have to go back to the drawing board -- and push things off for another decade. Politicians don't like that -- especially when they've been coerced into thinking past their next election!
ITER will be a very large-scale test device. Some of the phenomena that we see disrupting our current experiments are related to physical device size. Additionally, fusion power production is volumetric, while losses from the plasma come from the surface area of the confined plasma. Therefore, scaling up the size will boost fusion output, making it easier to "breakeven" (power out == power in) and, in ITER's case, very likely "ignite" (after reaching a critical temperature, you can turn off external heating and the plasma burning supplies the rest).
Of course, such scaling takes Lots of Money. Superconducting magnet coils are pricey; so is requisite neutron shielding. Current designs incorporate a Lithium "blanket" which will both absorb the 14 MeV neutrons (shielding) and produce tritium (amazingly, more T than you seed the plasma with initially!). One of the biggest question marks is in the field of materials. Nothing has been built that is going to take the neutron punishment that ITER will dish out to plasma-facing surfaces. It is such an important task to design materials that can sustain bombardment that a separate facility will be constructed simultaneously with ITER in Japan to study neutron bombardment exclusively. This has implications in the divertor material (high-Z tungsten or something lighter?) as well as blanket design.
2) My personal opinion is that it is best to stick with our Gen-IV nuclear plants when it comes to fission. These are meltdown-proof, high-efficiency plants that are designed for rapid implementation, should there be a willing buyer. A tabletop-size fusion device would be a relatively inefficient method of starting a fission plant; there are plenty of natural neutron sources that can be made by mixing radioactive materials together. Essentially, it'd be cheaper to use our existing designs for a big fission plant than mixing a fusion reactor's blanket design with a subcritical fission design.
Is this actually Deuterium - Deuterium fusion, or is it just making Hydrogen radioactive ?
The point of the story is that it doesn't matter what the specific technology is (the writers picked cold fusion because it was in the news at the time) but that the population at large cannot be trusted with that much power. It's bad enough that we have Kim Il Jongs and the rest, but the cost of nuclear weapons means that only nation states can divert the resources to build them. This makes their deployment and use subject to influence by other nation states. Sure, groups like Al Quaeda and others may be able to steal them, or even build a crude weapon using stolen fissionables. But if anyone with a screwdriver could build something as powerful ... yes, I think civilization would end fairly quickly.
The higher the technology, the sharper that two-edged sword.
Humans must have a genetic belief system that stops total genoicide.I cant see how this speicies could survive without it.
i'm little bit more worried about other guy, whos name rhymes with 'rush'.. heard he started two wars already..
NASA is sends a probe with a really big microphoone near to Sun - to detect the exact ferquency for fusion to work.
Oh, wait.. Sun is running on not-so-cold fusion..
Kravlor, You're right on the money, and I couldn't have said it better myself. Politics is one of the ultimate limiters of science. The biggest fight of ITER for the past 15 years was where is it going to be? Not who's going to spend the most on it or any other matter, but rather like a one-upsmanship game where whoever hosts it gets bragging rights. Politicians love that kind of thing and that's why I think it wasn't started any sooner. Sure we could've broken ground on the foundation and started manufacturing the structure on the main and supporting buildings, while waiting on newer, more resilient superconductors for the magnets, along with other bits and pieces. Then just piece it together as things become available. But you can see that it's the politicians holding back the engineering, not a lack of testing, theory, or engineering ability. So the old addage of 50 years until fusion is a great injustice since it's not a fault of the engineers at this point. I'd give it 10-15 after the second ITER test facility in Japan is built before we see fusion as a viable option for commercial power (and that's a somewhat conservative estimate since we don't quite know how long it will be between the first and second facilities are built). Second comes the materials issues. I can't wait to see what alloy they end up using for the divertor plate (this coming from a guy who spent many a sleepless nights modeling these things in Fluent for part of a degree).
I'm not so sure what is meant by a hybrid though. If you mean using a simple neutron source as a supplement to the neutron economy within the commercial reactor, then I'd say that you'd be wasting your time. The limiting factor in commercial plants is the rising levels of neutron poisons within the fuel that steal away neutrons that could be used to produce fission, but are left to be absorbed into xenon or numerous other poisons. AmBe or PuBe sources are already present in most commercial plants as a means to jump start the initial k-effective. You might be able to expand the length of a once-through cycle by a few days or so with a really powerful source, but if you're talking a little table-top fusion device, then I doubt the materials these guys are using to build those would be able to stand up to the conditions inside a commercial reactor. The corrosive properties of water at the high pressures and temperatures, along with kerma effects will destroy just about anything after some time. This little fusion neutron source would have to be inside the plenum and very close to, if not in the middle of, the core if it will make any dent in the k-effective. So I think you'd be much wiser to just go to reprocessing and put the remaining U, Pu, Am, and Cm back into the reactor for a few more go-rounds, also you'd cut way down on the repository needs. But that's a whole other can of worms. But once again I agree with kravlor there, moving towards the AP-1000's or even the older AP-600 design (but why the 600 when you can have the 1000 unless it's declined by the NRC?) would be a much better use of fuel than many subcritical assemblies. Unless you're into BWRs in which case I have very little clue on what route you would go for future plants since those are well outside my scope.
Now, if this little device can prove itself, then hospitals may have a nice new, controllable neutron source for irradiating tracer isotopes. So there's something this could be useful for that would make sense.
I hear it's ~10 $G for iter. That's not exactly chump-change. Especially since we're not actually sure that even after ITER we'll have a working plant or a path to one. In addition, your scaling arguments (I've heard elsewhere that the minimum size of a plant would have to be ~10 GW) imply very very large plants. That may be to large to be feasible - a 10GW plant is a pretty big investment.
One problem with very large tokamaks is that although they are above breakeven, it's not by much - which means that you have to recirculate large amounts of power. That makes for a very large and expensive generator facility.
I also understand that the amount of tritum circulating in a working plant would be enormous; much, much larger than ever used before. Tritium is notoriously hard to keep contained - so it's not obvious that a fusion plant wouldn't have issues with radioactivity releases...
My personal opinion is that it is best to stick with our Gen-IV nuclear plants when it comes to fission.
(Actually, I wasn't thinking of a hybrid based on tabletop fusors, but rather tokamaks). Wouldn't a hybrid allow you to use a smaller (and presumably more feasible) tokamak as a neutron source, while at the same time the sub-critical fission blanket could be designed very safe, since neutron economy isn't such a driving concern? You can imagine a blanket that gives a gain factor of 100, and a tokamak at 0.1 of breakeven, and you still have a feasible plant.
In addition, it would allow you to burn U238 or even nuclear waste instead of just U235. Seems like a win-win-win to me. Fusion gets operational experience and increased development funding, the country gets a good nuclear energy source, we're no longer oil-dependent or dependent on limited amounts of U235, and it reduces the waste issue (which is what is going to kill even the Gen IV plants). As an aside, it's interesting to note that even nuclear weapons are fission/fusion hybrids... we've never extracted pure fusion energy in any quantities, controlled or not.
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
So maybe Fred Hoyle wasn't convinced either, but the evidence for the Big Bang is pretty close to overwhelming at this point. It's not impossible that someone who believes that the Earth is flat can come up with a H-B fusion device, either, but it would seem a little unlikely.
If it can't generate enough power to run a laptop, what good is it?
If this is really D+D fusion, what purpose could neutron seeding possibly serve?
When you rely on statistics to show something, instead of some directly measurable parameter, then you know you've got a wet squib.
Engineering is the art of compromise.
Checkout http://pesn.com/2005/06/26/9600116_Naudin_MAHG/
and http://jlnlabs.imars.com/cfr/index.htm/
Experimenter claims to derive free energy cleanly and safely from the dissociation and association of hydrogen atoms. Data posted from several tests. Plans, schematics, methods all listed openly to encourage replication and improvement of results. Based on decades-old concepts set forth by Nobel laureate.
Everday 12:05
Rush.
Boosh.
Not the same.
Reminds me of the argument I frequently use to prove that time travel (at least to the past) is, and always will be impossible. If it can be done, at any point in the future of the universe, it will be done. From the time of its invention until the end of the universe should be a length of time close enough to infinite for this purpose. So the fact that we have not been awash in time tourists from this gargantuan period of time after the eventual invention of time travel shows that it will never happen.
[I usually explain it more eloquently than that, but I'm usually not explaining it at the end of a very gruelling day at the office.]
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
That's assuming that a) We'd recognize them even if they were here, b) that we live in a time and place so interesting that they'd bother, and c) that they can't just view this time remotely, and thus avoid any contamination of the timeline (assuming such is possible). Thus, sir, I dispute your conclusion.
No. Make a tokamak that runs at 0.1 of breakeven. Surround it with a blanket of U238 at k=0.99 (gives a gain factor of 100). The net result is a plant gain of 10, which is reasonable for a power plant. The fission supplies most of the energy, and the fusion most of the neutrons. Since the blanket is sub-critical it can be made safer than a standard fission reactor, and/or can use fuels that you couldn't otherwise use (i.e. an actinide burner, to get rid of the waste products). You don't have to bust your a** building a tokamak that does breakeven, that way.
It seems something like that would be the only way to get anything fusion-related actually producing power any time before my kids go to college... Think of it as an approach to getting fusion seen as an actual, viable choice to replace coal, and not just pie-in-the-sky.
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
A friend of mine was working in a lab at an island somewhere in the pacific. He said that he was very close to achieving TableTop fusion. No word from him yet. Its been almost 50 years and still no word since his last mail.
I dismiss all of those by asserting that given the nearly infinite time frame involved, a nearly infinite range of temporal tourists (most likely reeking of coconut suntan lotion, as tourists of all stripes are wont to do) will have washed ashore, and that if only a few break their locality's version of the Prime Directive, that small fraction multiplied by a nearly infinite number...
Of course, random teenagers taking Dad's time machine on a Friday night and wreaking havoc in the past would be about the only thing that could explain why this current timeline is getting vastly stranger every year than could ever be explained by human nature and entropy stirred together in a bubbling cauldron. In fact, if you will allow me to trot out my most shopworn Jim Morrison quote, "This is the strangest life I've ever known."
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
Dude - how else do you explain Dennis Rodman?! Okay, I guess he could be merely an alien from this timeline, but ... I dunno.
:)
re: infinite time = infinite timetravelers
I think this is the critical assumption here, which is unlikely to be true. Despite space being infinite, there seems to be a finite amount of matter contained within it, thus a finite set of possible entities. When you take into account the recent stories of there being a much more limited set of intelligent-life-conducive areas (due to radiation) than previous estimates have said, the likelihood of so many 'infinite' timetravelers becomes especially small. Now, just because time 'may' be infinite (not currently provable by our technology), that doesn't mean that intelligent life will always be around. At some point, assuming a species survived long enough, I could easily imagine them involving into a non-corporeal existence. This would easily explain the non-proven sightings of time travelers. And again, with your 'infinite' guidelines, it comes much less likely that the here and now of our existence is even interesting enough to bother with, even assuming we COULD see them, or recognize what we're seeing.
Plus, the Temporal Prime Directive _is_ enforced, you know.
The point of the story is that it doesn't matter what the specific technology is (the writers picked cold fusion because it was in the news at the time) but that the population at large cannot be trusted with that much power.
Indeed. Even the North Koreans, at best, can only destroy a half-dozen cities. Maximum global impact, at a liberal estimate of five million killed by the blast and ensuing radiation, 30 million... out of 6 billion.
That means that a lunatic pouring the output of an entire country into planetary catastrophe can wipe out only nothing more than one-half of one percent of the Earth's population. Absolutely devastating losses that would be felt by every sentient being on the planet, but not enough to wipe out the species, or even the more fragile concept of "civilization".
Put a million-people-killer in the hands of every Osama bin Laden, Timothy McVeigh, Aum Shinrikyo, and Unabomber... then, you've got trouble on an evolutionary scale.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
How would you get a .99 k-effective out of U-238? Even with fuel lumping I don't see it. Unless you're already including the neutrons provided by the fusion reaction, but the problem with that is that a tokamak is a pulsed device which rules out normal k-effective equations so you can't assume steady state of the neutron flux but rather a sinusoidal which if you try to "fix" the flux it would balance out much lower than expected for a steady state beam. Also looking at the first, second, and third chance fission cross sections for U-238 I'm not seeing how that would even be possible for a natural uranium blanket would absorb the neutrons at that high of energy even with the doppler broaded cross sections at the high temperatures in a standard core. I'd check with MCNPX if you have access to it and use the added neutron physics and do a simple kcode to check this, but make sure you have doppler broadened and unresolved region linearized cross sections since you're dealing with high energies (although that might skew it a little, but it's a rough estimate afterall). The U-238 is on the order of 10^-4 barns for the highest fission XS. Also how could you get that much uranium inside the magnets? It's a very tight fit between the magnets and the actual fission chamber. Also rarely is pure uranium metal ever used except for in a godiva sphere setup or other experiments, but never in an actual setting. The reason for that being twofold, first for structural support and second for moderating effects. Most likely this fuel would have to be a carbide, oxide, or possibly even a nitride. You're right about the actinide burner. I've read a few papers (Fusion Science from this past May I believe and some a few years back) written on using a tokamak as a MA transmutation reactor which said that the outer core wouldn't be anywhere near critical though, which considering that the minor actinides used would be mostly Pu-239, as expected, which has a rather high cross sections (10^7 higher than the U-238 for fission) only reached a k-effective of ~.4 or so for a fusion reactor with ITER's dimensions. So I'm not so sure about using a blanket of U238.
The other thing to remember is that if you don't need the fusion to be at break-even, you can make the tokamak smaller. That makes it easier to get a good value for k, I'd imagine. Should also allow you to get away from superconducting magnets.
Your point about the U238 cross section vs 14 MeV neutrons is interesting. How about moderating them somewaht, say using the Lithium blanket that has to be there anyway?
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
The problem with putting the fuel in the middle of the tokamak is that it's very dense in there. The toroidal and poloidal magnets, inner shielding, cooling units, and related cabling/equipment take up much if not all of the room in the inner ring so putting fuel and related cooling in the center is one of those things that was ruled out after some research. So the only place you can really put the fuel is in the outermost portion, within the magnets but outside the pressure vessel (the magnets being more D-shaped and the plasma chamber being a deformed oval leaves some room to the outermost). Lithium doesn't make a very good moderator though, better than most since it's low-Z but it would still take quite a few interactions to slow down a 14 MeV neutron down to the energy that U-238 would absorb. U-238 absorbs most in the 1/v range (low energy from about .1eV to .00253eV/thermal range), so you'd really have to slow down the neutrons to get to that range, and when slowing down neutrons, every collision matters to decrease the possibility of leakage. Hence it's much better to use fast spectrum actinides like Np, Pu, Am, and Cm for a fusion neutron source. As for the neutron flux distribution, it's pretty strong all over, except it's the strongest on the outside of the toroid since that's where the plasma density is the greatest so the majority of neutrons are slung outwards due to some of the more enjoyable aspects of plasma physics (drift motions and whatnot). So the best place to collect the neutrons is on the outside. Using different sizes of tokamaks is possible, but actually achieving fusion requires certain geometry constraints. Since the plasma is pulsed, the field is constantly changing and that relates directly with the plasma temperature. So you can't make it too small otherwise you can't reach ignition temperatures (~5keV for most). If you're still curious about some of the cross sections, there's an online plotting cgi gateway at the Korean Atomic Energy Research Institute (http://atom.kaeri.re.kr/). Cool stuff but not doppler broadened for the range used in fusion reactors.