Nuclear fusion simulation shows high-gain energy output

Mar 20, 2012
Prototype assembly of MagLIF system - the top and bottom coils enclose the lit target. (Photo by Derek Lamppa)

(PhysOrg.com) -- High-gain nuclear fusion could be achieved in a preheated cylindrical container immersed in strong magnetic fields, according to a series of computer simulations performed at Sandia National Laboratories.

The simulations show the release of output energy that was, remarkably, many times greater than the energy fed into the container’s liner. The method appears to be 50 times more efficient than using X-rays — a previous favorite at Sandia — to drive implosions of targeted materials to create fusion conditions.

“People didn’t think there was a high-gain option for magnetized inertial fusion (MIF) but these numerical simulations show there is,” said Sandia researcher Steve Slutz, the paper’s lead author. “Now we have to see if nature will let us do it. In principle, we don’t know why we can’t.”

High-gain fusion means getting substantially more energy out of a material than is put into it. Inertial refers to the compression in situ over nanoseconds of a small amount of targeted fuel.

Such fusion eventually could produce reliable electricity from seawater, the most plentiful material on earth, rather than from the raw materials used by other methods: uranium, coal, oil, gas, sun or wind. In the simulations, the output demonstrated was 100 times that of a 60 million amperes (MA) input current. The output rose steeply as the current increased: 1,000 times input was achieved from an incoming pulse of 70 MA.

Since Sandia’s Z machine can bring a maximum of only 26 MA to bear upon a target, the researchers would  be happy with a proof-of-principle result called scientific break-even, in which  the amount of energy leaving the target equals the amount of energy put into the deuterium-tritium fuel.

This has never been achieved in the laboratory and would be a valuable addition to fusion science, said Slutz.

Inertial fusion would provide better data for increasingly accurate simulations of nuclear explosions, which is valuable because the U.S. last tested a weapon in its aging nuclear stockpile in 1992.

The MIF technique heats the fusion fuel (deuterium-tritium) by compression as in normal inertial fusion, but uses a magnetic field to suppress heat loss during implosion. The magnetic field acts like a kind of shower curtain to prevent charged particles like electrons and alpha particles from leaving the party early and draining energy from the reaction.

The simulated process relies upon a single, relatively low-powered laser to preheat a deuterium-tritium gas mixture that sits within a small liner.

At the top and bottom of the liner are two slightly larger coils that, when electrically powered, create a joined vertical magnetic field that penetrates into the liner, reducing energy loss from charged particles attempting to escape through the liner’s walls.

An extremely strong magnetic field is created on the surface of the liner by a separate, very powerful electrical current, generated by a pulsed power accelerator such as Z. The force of this huge magnetic field pushes the liner inward to a fraction of its original diameter. It also compresses the magnetic field emanating from the coils. The combination is powerful enough to force atoms of gaseous fuel into intimate contact with each other, fusing them.

Heat released from that reaction raised the gaseous fuel’s temperature high enough to ignite a layer of frozen and therefore denser deuterium-tritium fuel coating the inside of the liner. The heat transfer is similar to the way kindling heats a log: when the log ignites, the real heat — here high-yield fusion from ignited frozen fuel — commences.

Tests of physical equipment necessary to validate the are already under way at Z, and a laboratory result is expected by late 2013, said Sandia engineer Dean Rovang.

Portions of the design are slated to receive their first tests in March and continue into early winter. Sandia has performed preliminary tests of the coils.

Potential problems involve controlling instabilities in the liner and in the that might prevent the fuel from constricting evenly, an essential condition for a useful implosion. Even isolating the factors contributing to this hundred-nanosecond-long compression event, in order to adjust them, will be challenging.

“Whatever the difficulties,” said Sandia manager Daniel Sinars, “we still want to find the answer to what Slutz (and co-author Roger Vesey) propose: Can magnetically driven inertial fusion work?  We owe it to the country to understand how realistic this possibility is.”

The work, reported in the Jan. 13 issue of Physical Review Letters, was supported by Sandia’s Laboratory Directed Research and Development office and by the National Nuclear Security Administration.

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Scottingham
4.3 / 5 (16) Mar 20, 2012
"We owe it to the country to understand how realistic this possibility is."

Correction: you owe it to the world!

PS - your name is funny!
Kinedryl
1.1 / 5 (48) Mar 20, 2012
We owe it to the country to understand how realistic this possibility is
I do agree - the researchers of hot fusion are becoming a bit desperate, because the cold fusion is economically way more advantageous, not to say about its scalability. And it works even without expensive simulations. http://www.infini...emo.html
I owe it to all people to understand, how big waste of public money this research actually is.
Raygunner
4.6 / 5 (8) Mar 20, 2012
It looks like this may be lot more compact than other alternatives. If initial tests prove the theory - this ought to have the same priority as our moon program in the 60's. With the perfection and miniaturization of the technology, industrial and home units could be a reality within 30 or 40 years. Just imagine if we were able to loose the power grid and high tension wires strung all over the US. You would have the Culligan man delivering bottled seawater to your house to feed your fusion reactor!
Kinedryl
1.1 / 5 (16) Mar 20, 2012
It looks like this may be lot more compact than other alternatives
It's way less compact than the tokamak, for example. Actually, Z-accelerator is huge. http://www.sandia...vate.jpg
Lurker2358
2.3 / 5 (10) Mar 20, 2012
You would have the Culligan man delivering bottled seawater to your house to feed your fusion reactor!


Then they'd find a way to charge you outrageous prices for water.
Scottingham
4.7 / 5 (25) Mar 20, 2012
The difference between cold fusion and hot fusion scientists is that one group follows the laws of thermodynamics, the other isn't aware of them.

Guess which is which...
Kinedryl
1 / 5 (26) Mar 20, 2012
In which point the cold fusion violates the thermodynamics? IMO it's based on the same thermodynamical principle, like the hot fusion or coalesce of mercury droplets, for example. Smaller droplets do always merge into larger ones. Actually, such a merging occurs the more easier and spontaneous way, the larger these droplets are. From this reason we can just expect, the merging of hydrogen with relatively large nickel nuclei will happen easier, than the mutual merging of two protons.
Kinedryl
1 / 5 (27) Mar 20, 2012
But the main trick of cold fusion is in simple point: the merging of hot naked atom nuclei is always way more difficult, than the merging of whole atoms. Why? At the tokamak or Z-pinch fusor you're excerting an energy to strip the electrons from atoms. The striped atom nuclei are strongly repulsive due their positive charge - so you should exert additional energy to achieve their merging.

Such a brute force approach may become completely unnecessary (if not a waste of activation energy) - if you would keep the atom nuclei covered with electrons, which will compensate their positive charge. The binding energy of electrons will help you to overcome the Coulombic barrier between atom nuclei. The neutral atoms will merge as easily, like the neutrons, after then.
Kinedryl
1 / 5 (21) Mar 20, 2012
So far the physicists didn't believe, that the electrons could shield the atom nuclei in very effective way. It's because they're always considered the merging of lightweight atoms. Such an atoms don't bind their electrons very strongly and even small energy is sufficient to remove them. We can compare it to the ease, in which we can peel the flesh from stone of apricot fruit, from example.

But the heavier atoms are quite different, as the binding energy of electrons increases with number of electrons in quite remarkable way. At the case of nickel nuclei it's virtually impossible to remove all electrons from nuclei without breaking of atom nuclei itself with using of X-rays: before last electron is removed, some protons or neutrons will get removed too.

It's similar to the peeling the mango fruit: you can never succeed with it in full extent. The electrons are forming the energetic continuum around atom nuclei and as such their shielding of positive charge is very effectively there.
Kinedryl
1 / 5 (24) Mar 20, 2012
At the moment, when some X-ray photon is able to remove both the electrons, both the protons from atom nuclei at the same moment, we can just ask, if such process cannot proceed in the opposite way: the protons of hydrogen nuclei would merge with electrons at the bottom of nickel orbital under releasing of X-ray photon. The fact, nickel or palladium are forming hydride anions with hydrogen helps this situation a lot - the proton inside of hydride atom is partially sucked beneath the surface of metal atoms and it becomes more close to nickel nuclei here.

Actually, we already know about another thermodynamical process, which appears as infeasible, as the nuclear fusion at the first sight - yet it proceeds smoothly: it's the splitting of water with radiowaves http://www.youtub...lIm5a1Lc
Scottingham
4.5 / 5 (15) Mar 20, 2012
kinedryl, cites or its pseudoscience jargon.
mattytheory
5 / 5 (5) Mar 20, 2012
Slutz and company may one day save the world!
Kinedryl
1 / 5 (21) Mar 20, 2012
The merging of protons in hot fusion requires the activation energy in the range of 10 MeV, which corresponds the effective temperature hundred of gigakelvins. It's apparently too much for being allowed with electrolysis at palladium, which occurs at ~ 1 eV at room temperature. It's difference of eight orders of magnitude - no question about it...

But the splitting of water molecule requires the energy about 1.2 eV. Under normal circumstances the water cannot be splitted even with hard ultraviolet radiation. Yet it occurs under action of 10 MHz radiowaves, which are having the energy density at the range 10-8 eV. It's exactly the same ratio of eight orders in magnitude, like at the case of nuclear fusion. It just indicates, both these phenomena do share certain common mechanism at the general level. And this mechanism is known for contemporary physics already too - it's called the Mossbauer resonance.
Kinedryl
1 / 5 (21) Mar 20, 2012
The Mossabauer resonance is lattice effect, which can be illustrated by shaking of sand inside the closed vessel. It would require quite lot of energy to achieve the generation of visible sparks in this way. But if we use a larger pebbles, then the visible sparks can be observed even under mild shaking. If we manage to collide the atoms in form of larger clusters, we can achieve the local increasing of energy density in similar way, like inside of famous Astroblaster toy. The water manages it with formation of water clusters, and the nickel or palladium manages it with formation of proton clusters within metal lattice. All these processes and phenomena are known already and they do violate the known physics with anything - the only trick is, you should apply them at all together. When handled separately, no effect is able to explain the cold fusion by itself. Which makes a problem for schematically thinking people.
Kinedryl
1 / 5 (21) Mar 20, 2012
The water is known to be formed with icosahedral clusters containing the 280 water molecules per cluster. The mutual collision of 280 molecules at the same moment is able to increase the energy density by 280 x 280 x 280 = 22.000.000 i.e. roughly in eight orders of magnitude.

The splitting of water with radiowaves is exceptional in another aspects. For example, during it no oxygen is actually formed. It just generates the pure burnable hydrogen and hydrogen peroxide. This is a metastable mixture, which produces large amount of heat at elevated temperature. But because the splitting of water occurs at low temperatures (every hot molecule is surrounded with many others, which are cooling the product fast), the metastable products are formed.

One problem of physics with cold fusion consist of fact, no neutrons or energetic particles are released during it. The formation of such particles is predicted with hot models of fusion, but in cold fusion the metastable products are favoured.
Husky
5 / 5 (7) Mar 20, 2012
this hybrid approach looks great because the lawson criterion is a notorious slippery eel , you have to grap it with both hands
TheGhostofOtto1923
4.1 / 5 (10) Mar 20, 2012
how big waste of public money this research actually is.
Even if LENR does prove to be a viable source of energy there is still a great need to develop the tech and the knowledge base for containing, manipulating, and transporting large quantities of plasma. LENR will not produce enough energy to serve as spacecraft propulsion for instance, but inertial confinement can, and will.

Plasmas in bulk will be used in manufacturing when great quantities of material are produced by plasma deposition. Antimatter can only be stored in plasma form.

There are many very critical reasons for developing plasma tech; and the promise of abundant commercial power, whether real or not, is a convenient way of generating support for this effort. As we can see.

Fossil fuel production has enabled the west to maintain influence in areas around the globe where ancient religionist cultures threaten peace and stability. Oil will not be replaced until it is sociopolitically possible to do so.
MCPtz
4.7 / 5 (3) Mar 20, 2012
I live near the Ocean :). Can't wait to see their follow up work.

Also, the published material link. If it wasn't $25 I'd consider reading it:
http://prl.aps.or.../e025003
Callippo
1 / 5 (16) Mar 20, 2012
You can check this presentation - it's way more accessible for average PO readers. Anyway, it's a crap from technological perspective. One such device consumes more money, than the whole cold fusion research during last twenty years.
PosterusNeticus
4.5 / 5 (11) Mar 20, 2012
The reader is advised to ignore the comment section. Of course, if you're reading this then it's already too late; your eyes and brain have been victimized by the resident kooky cats. You'll know better next time!
Newbeak
5 / 5 (7) Mar 20, 2012
Thorium reactors are the answer! Check out this TED talk:http://www.bspcn....funding/
bewertow
4.3 / 5 (15) Mar 20, 2012
We owe it to the country to understand how realistic this possibility is
I do agree - the researchers of hot fusion are becoming a bit desperate, because the cold fusion is economically way more advantageous, not to say about its scalability. And it works even without expensive simulations. http://www.infini...emo.html
I owe it to all people to understand, how big waste of public money this research actually is.


Yea hot fusion researchers definitely feel threatened by something which is completely ineffective and unproven. LOL!

On the other hand, almost all the energy we consume on Earth is fundamentally generated by a giant hot fusion reactor: the sun.
Twin
1.3 / 5 (10) Mar 20, 2012
Seems to me Hot fusion is also ineffective (and barely possible).
Urgelt
1.7 / 5 (7) Mar 20, 2012
Bah. I suspect magnetized inertial fusion is a lot of barking up the wrong tree. They aren't showing us a route to miniaturization and commercialization; all they see is the need for ever larger and more complex installations with ever more delicate and wicked-fast field modulations. Billions of dollars for a few hundred watts is all we'll ever see out of 'em.

Which is *not* an endorsement of the cold fusion fringe. Wishful thinkers on steroids with some scammers thrown in, that bunch.

Heh. I am remembering Project Orion. Now there were some scientists willing to think out of the box. Hardly practical for power generation, though.

I think we need a new approach, or fusion just isn't going to be a factor in the next hundred years of civilization.

How about we stick a flask of deuterium between a couple of JBL speakers and crank 'em up? Think of the fun researchers would have experimenting with different music. :-)
ubavontuba
1.4 / 5 (18) Mar 21, 2012
"Nuclear fusion simulation shows high-gain energy output"

Zowie! My computer shows simulations of propellantless flying cars and people with superhuman powers. Let's pretend they're just as close to reality as well! (snicker)

Engineers have long worked with mathematical models which "prove" various hot fusion concepts. This is nothing new. It's just a fancy new flute for the Pied Piper of fusion.

The difference between cold fusion and hot fusion scientists is that one group follows the laws of thermodynamics, the other isn't aware of them.

Guess which is which...
I'm going to suggest neither, as no attempt at either controlled cold or hot fusion (AFAIK) has ever successfully produced an abundance of surplus energy.

Therefore and arguably, hot fusion is no more successful than cold fusion. But since hot fusion costs a lot more, I'm going to say cold fusion has been more successful at being practical.

But then again, hot fusion has provided many times more jobs...
Kinedryl
1.7 / 5 (13) Mar 21, 2012
By Dr. Mitch Swartz of MIT his demo that he did for the "Cold Fusion 101" class is still running, and has been doing so continuously for two months at 7-times overunity...

http://coldfusion...t-again/

Therefore and arguably, hot fusion is no more successful than cold fusion. But since hot fusion costs a lot more, I'm going to say cold fusion has been more successful at being practical.

But then again, hot fusion has provided many times more jobs...
Cold fusion definitely wins in overunity section. Also, the total energy generated in this way is definitely higher, than at the case of hot fusion.
antialias_physorg
5 / 5 (4) Mar 21, 2012
I hope they don't run nito the same problem as other implosion schemes (i.e. small scale effects that lead to uneven implosion shockfronts).
Magnetic implosion seems more controllable that way so they should definitely give it a go.

Then they'd find a way to charge you outrageous prices for water.

The amounts used are miniscule.
Szkeptik
1 / 5 (4) Mar 21, 2012
I'm not really at home with fusion research.
Is this a big thing? More importantly is this a thing that will become useful in less than 50 years?
Kinedryl
1 / 5 (7) Mar 21, 2012
This article essentially says, we failed with establishing of inertial fusion with using of Sandia Z-machine or laser fusion at NIF, so we should try to combine it.

IMO it cannot work from the simple reason: the more you compress the pellet, the hotter it will be, the lower time the atoms will have for their fusion. Lawson criterion is not about blind increasing of energy density, but about finding of "magic numbers" in energy density and time due the resonance effect during neutron capture.

If you will not find these islands of hot fusion, then the more effortful heating will not make the things better, but worse.
TheGhostofOtto1923
3.3 / 5 (9) Mar 21, 2012
Bah. I suspect magnetized inertial fusion is a lot of barking up the wrong tree. They aren't showing us a route to miniaturization and commercialization; all they see is the need for ever larger and more complex installations with ever more delicate and wicked-fast field modulations. Billions of dollars for a few hundred watts is all we'll ever see out of 'em.
Miniaturization depends on the continued development of ancillary tech - superconductors, lasers, control systems, materials, shielding - and not the fusion research itself. The intent is to mature the knowledge of plasma as this other tech develops in parallel.

Further, much of this tech is essential for other uses - space colonization for instance, where shielding and radiation-resistant materials are vital - and would not be developed without this fusion research. Hot fusion, like star wars and the space program, is producing valuable spinoffs which would not occur otherwise.
TheGhostofOtto1923
3.9 / 5 (7) Mar 21, 2012
I'm not really at home with fusion research.
Is this a big thing?
Yes.
More importantly is this a thing that will become useful in less than 50 years?
Yes. As I explained it is being useful now.

Try GOOGLE and educate yourself. This works better than asking opponents and numbnuts here to try explaining it to you.
antialias_physorg
4.9 / 5 (8) Mar 21, 2012
the more you compress the pellet, the hotter it will be

Which is the point of fusion
the lower time the atoms will have for their fusion.

Which is the point they are addressing (if you read the article) - by magnetically restricting the escaping of hot particles from the plasma to increase the timeslot fo fusion.
Cluebat from Exodar
1.7 / 5 (6) Mar 21, 2012
Conveniently released at the same time as the House Budget Plan.

I think they keep these concepts on the shelf until it's time to generate some public support.
antialias_physorg
4.9 / 5 (9) Mar 21, 2012
Conveniently released at the same time as the House Budget Plan.

What's 'convenient' about it? Isn't it the POINT of demanding reports by the budgetary comittee when they do budgetary decisions? What else would they base their decision on but the curent state of the work being done?

Don't go looking for conspiracies when that's just common sense at work.
Cluebat from Exodar
1.8 / 5 (10) Mar 21, 2012
Not conspiracy, Business as usual.

We've been told that cheap energy via hot fusion has been just around the corner for fifty years.

I do not support this research any longer. I lost interest twenty years and $50B ago.
Pyle
1 / 5 (2) Mar 21, 2012
We've been told that cheap energy via hot fusion has been just around the corner for fifty years.
Hmmm, my information was that cheap energy from hot fusion was bombarding us everyday. My opinion is we need to continue finding ways to utilize the energy from the massive reactor in the sky. But since we are talking about fusion technology...

Was anyone else a little frightened by the note about needing to develop this to test nuclear weapons technologies? It scares me more than a little bit that we still need to maintain any nuclear weapons at all. Too bad that people are people. Hopefully soon common sense will win out over greed and ambition.

Oh, and throw money at hot fusion. The technical advances it provides will be worth it even if we don't make it an energy source. (Throw money at LENR too just for kicks.)
MB2BM55
3 / 5 (2) Mar 21, 2012
Cold fusion is still a topic? I thought it was dead b4 the internet went public...

Anyway, this is interesting because I hadn't been exposed to any serious combo magnetic and inertial confinement methods yet. Probably because on their own, each of those is difficult and expensive enough
MB2BM55
5 / 5 (3) Mar 21, 2012
the more you compress the pellet, the hotter it will be

Which is the point of fusion
the lower time the atoms will have for their fusion.

Which is the point they are addressing (if you read the article) - by magnetically restricting the escaping of hot particles from the plasma to increase the timeslot fo fusion.


In addition, the very idea of Magnetic confinement is that higher temperatures means BETTER confinement and more fusion because the faster the charged particles are moving (remember that the electrons and and nuclei are disassociated in a plasma) the tighter circles the make around the magnetic field lines and the closer they are statistically and with higher energies to overcome the Coulomb barrier- raising the probability and therefore the rate of fusion.

@antialias- Don't want you to be offended by thinking I'm explaining this to you. Just adding for the people who have misconceptions of the goal.
kochevnik
1.7 / 5 (6) Mar 21, 2012
Primitive. Employing brute force instead of attempting to comprehend the magic numbers defining electron orbitals and unlocking the nucleus accordingly.
Urgelt
4.3 / 5 (3) Mar 21, 2012
Otto, sure, basic research is the cat's knees.

I'm just not seeing a path from here (current fusion research) to commercialization of fusion power generation within the next century. Unless, of course, the fusion generator is at a safe distance, like, say, 92 million miles or so, and nicely stable over human-scale time frames.

I wasn't entirely joking about the JBL speakers. Has anyone looked into sound-based compression of plasma as an adjunct to magnetic containment?

Meh, almost certainly not. Too far outside the box.

But I think if we stay in the hot fusion box as presently defined, we'll never get to commercial fusion power.
TheGhostofOtto1923
3.7 / 5 (6) Mar 21, 2012
wasn't entirely joking about the JBL speakers. Has anyone looked into sound-based compression of plasma as an adjunct to magnetic containment?
Bubble fusion
http://en.wikiped...e_fusion

Asgardian fusion
http://www.generalfusion.com/
antialias_physorg
4.8 / 5 (5) Mar 21, 2012
Unless, of course, the fusion generator is at a safe distance, like, say, 92 million miles or so, and nicely stable over human-scale time frames.

The beauty of fusion is that it can't go critical. As soon as any part of it fails (superconductors to confine the plasma, fuel injection method, whatever)...even if you inject TOO MUCH fuel - the thing stops.

The absolute worst that can happen is that the containment field breaks down and the inner part of the chamber comes in contact with the plasma - which immediately cools it down and makes it impure. This stops the reaction on a dime - even if the safeguard to stop injecting fuel would fail. In this case the chamber needs to be refurbished. That's it (an expensive 'it', though).

An inert rector is safe. The inner chamber does get to be irradiated over time - so there is SOME radioactive waste after the powerplant has gone through its lifetime. But that's nothing compared to what fission reactors produce.
antialias_physorg
5 / 5 (6) Mar 21, 2012
The fuel itself is non-toxic (deuterium...which behaves chemically identically to hydrogen in the body). So even a 'fuel spill' wouldn't cause any problems. Mix it with oxygen and combust it and you can drink the result.

You could drop a bomb or a plane on such a powerplant and the worst fallout from that are the parts of the bomb/plane lying about.
ziphead
1.8 / 5 (5) Mar 21, 2012

Yes. As I explained it is being useful now.
Try GOOGLE and educate yourself. This works better than asking opponents and numbnuts here to try explaining it to you.


Is it just me, or did you just indirectly admit to being a numbnut :)
Callippo
1 / 5 (6) Mar 21, 2012
So even a 'fuel spill' wouldn't cause any problems. .
LOL, it actually caused problems already, although it didn't produced a single watt of usable energy. http://www.nytime...tml?_r=2

Hot fusion produces the same amount of neutrons, like the fission in classical nuclear reactor. In addition, the fast neutrinos formed during hot fusion will make a brittle radioactive waste from every metal, which they met. Whereas the cold fusion means no neutrinos.
Newbeak
4.8 / 5 (5) Mar 21, 2012

The beauty of fusion is that it can't go critical. As soon as any part of it fails (superconductors to confine the plasma, fuel injection method, whatever)...even if you inject TOO MUCH fuel - the thing stops.

The same thing can be said for a thorium-fueled molten salt reactor system,which the Chinese and Indians are vigorously pursuing.Unlike fusion,fission is doable now,without any need for theoretical breakthroughs.Thorium molten salt reactors,among other advantages over pressurized light water reactors, are meltdown proof,able to automatically shut down without outside intervention.Check out this excellent article in The Telegraph: http://www.telegr...ium.html
Urgelt
3 / 5 (2) Mar 21, 2012
Otto: thanks for the links!

Anti: All true. Yet if we are scaling to produce gigawatts and terawatts of power, we'll be dealing with some pretty seriously large temperatures, which is a materials challenge even with awesome magnetic containment which at present we can't sustain for more than brief intervals. What we want is stability as well as a generous power yield, and it's not certain that outside of stars, stability is practical.

Newbreak: I have to wonder at the approval of yet more water-cooled fission-based nuclear power plants. Water dissociates into hydrogen and oxygen during an event, which risks containment building explosions, as we saw at Fukushima. Molten salt thorium reactors would seem to have a considerable edge in safety. But enriched thorium would still be a pretty good material to use in a radiation-enhanced conventional bomb, and so presents proliferation issues. Humans might be better off putting fission power entirely behind them.
sirchick
4 / 5 (2) Mar 21, 2012
As soon as i saw this article i knew there would be discussions on cold and hot fusion >.> Can we not stick to the one type of fusion for the article, namely the one it is referring to.
I don't get the point of constantly brining up cold fusion in here - keep them comments for articles about cold fusion.
antialias_physorg
4.5 / 5 (4) Mar 22, 2012
The same thing can be said for a thorium-fueled molten salt reactor system,which the Chinese and Indians are vigorously pursuing

At any rate you have radioactive thorium in there - which needs to be mined/refine and could be dispersed (by whatever accident or intentionally) - so it's not inherently safe.

which is a materials challenge even with awesome magnetic containment which at present we can't sustain for more than brief intervals

Since there is no handling issue (only a building issue) for the radioactivity there really is no reason why a powerplant should then be made up of one large chamber. Many smaller ones would do the trick, too (which would also be much better in case one chamber fails for whatever reason and maintenance has to be performed - especially in spacegoing scenarions redundant layout is preferrable).
Urgelt
not rated yet Mar 22, 2012
Anti, I agree, that's the best conceivable solution: small, distributed electrical power generation.

Now all we need to do is imagine how fusion can be done in a small, inexpensive form factor with good energy yields.

I'm sticking to my cranked-up JBL speakers! They're just as likely to get to our mutual goal as magnetic-inertial containment, and they're a lot cheaper. :-)

Acoustic compression got a bad name from bubble fusion some years back, or so I've read from Otto's link. Now it's a "fringe" idea supported by whack-a-doodles. But you know, acoustic science has progressed in recent years. Laser-like effects, hologram-like effects. It really would be fun to experiment with those kinds of things in combination with resonance and temperature modulation, and it ought not to be so expensive, as sound is much easier to manipulate than huge magnetic fields.

It's probably a real long shot. But long shots seem to be all we've got at the moment.
TheGhostofOtto1923
2.3 / 5 (3) Mar 22, 2012
The beauty of fusion is that it can't go critical. As soon as any part of it fails (superconductors to confine the plasma, fuel injection method, whatever)...
Again I feel compelled to qualify what you say...
The beauty of fusion is that it can't go critical. As soon as any part of it fails (superconductors to confine the plasma, fuel injection method, whatever)...even if you inject TOO MUCH fuel - the thing stops.
Superconducting coils which lose their cooling and regain their resistance can blow up real good. We saw what happened with the LHC; fusion reactor coils are many many times bigger.

Fusion reactors may use molten lithium or sodium for energy capture; these are pyrophoric and would also make quite a mess. The general fusion reactor will use molten lead.

D2 is not radioactive but tritium is, and it would be reclaimed and stored from activated lithium onsite. Lots of potential for major environmental disaster and much news footage here.
antialias_physorg
5 / 5 (6) Mar 22, 2012
Superconducting coils which lose their cooling and regain their resistance can blow up real good.

Quenching. Yes it can happen. But it's not really a problem with a minimum of (entirely passive) design

E.g. MRI apparatus use superconducting coils. The coils and cooling apparatus are divided into compartments. And each compartment has a vent. What 'blows up' in the event of quenching is actually the coolant being heated - because the superconductor went above Tc - and becoming gaseous. If that happens the gas is simply vented (which couldn't happen well at the LHC because it's underground). Since the coolant is either nitrogen or helium there is no danger for the environment whatsoever. The coils melt. That part, while expensive, isn't dangerous.
antialias_physorg
5 / 5 (5) Mar 22, 2012
So what you're not going to see is stuff on the order of magnitude of the hydrogen explosions of Fukushima, nor dispersal of dangerous radioactive material over more than 50 meters.

Even if Tritium were to escape: it is much less of a problem since it's not an alpha radiation source and in much lower concentration after an accident (only the part currently in the chamber would be emitted - which is minimal).

On top of that: compared to the beta radiation from ceasium tritium is 'harmless' (tritium emits a 18kV beta vs. caesium's 660kV betas...iodine 131 decays with the expulsion of a 606kV beta). Tritium is also lighter than air as opposed to all the gunk you get after a fission accident.
antialias_physorg
5 / 5 (5) Mar 22, 2012
Again I feel compelled to qualify what you say...

You don't expect me to be abe to fit a full technical explanation of all aspects of fusion power plants into 1000 words, do you?
TheGhostofOtto1923
2.3 / 5 (3) Mar 22, 2012
a minimum of (entirely passive) design
-Not sure what you mean by 'passive', but you did say:
The absolute worst that can happen is that the containment field breaks down and the inner part of the chamber comes in contact with the plasma...
-But the absolute worst thing that could happen is that they could EXPLODE in massive fireballs of ignited metal.

"MRI are in the 0.5-Tesla to 3.0-Tesla range, or 5,000 to 30,000 gauss.

"The ITER toroidal field coils are designed to have a total magnetic energy of 41 gigajoules and a maximum magnetic field of 11.8 tesla. The coils will weigh 6,540 tons total..."

-Not to mention the poloidal coils and central solenoid, all superconducting. Obviously a totally different scale and potential for catastrophic failure on the order of the hydrogen explosions at fukushima; or perhaps worse.
TheGhostofOtto1923
2.3 / 5 (3) Mar 22, 2012
More ominous info:

"MHD instabilities leads to a dramatic quench of the plasma current on a very short time scale, of the order of the millisecond. Very energetic electrons are created (runaway electrons)...In the ITER tokamak, it is expected that the occurrence of a limited number of major disruptions will definitively damage the chamber with no possibility to restore the device. This critical issue is rarely debated by the promoters of the project...it will be very difficult to mitigate the disruptions that pose a significant challenge in future tokamaks where the increased stored energy can lead to unacceptably large transient heat loads on plasma facing components."

-Could this lead to a breach of the containment vessel in a commercial reactor and subsequent critical damage to cryo field coils, initating a failure cascade which devastates the whole COUNTRYSIDE? I think maybe yes.
TheGhostofOtto1923
2.3 / 5 (3) Mar 22, 2012
Tritium is already a concern at nuclear reactors:
http://www.nrc.go...ium.html

-At TFTR there was an exclusion area established around the facility in the event of a release. In a commercial fusion reactor they will be processing the lithium to remove the tritium created as the lithium is irradiated. This will be used in the fusion reaction. I assume the quantities will be greater as well as the potential for release. Especially if the thing EXPLODES.
You don't expect me to be abe to fit a full technical explanation of all aspects of fusion power plants into 1000 words, do you?
Naw just the important stuff.
TheGhostofOtto1923
2.3 / 5 (3) Mar 22, 2012
More ominous info:

"Multimegamp e-beams at energies of ~ 10 20 MeV loose inside of ITER simply cannot be tolerated, and will likely cause catastrophic failure of thin first wall components in exactly one occurrence...When Millions of Amperes of runaway electrons are produced as a result of a single disruption, orbiting in ITER, then you have created a huge e-beam welder when they finally impact on something physical."

and

"Did TFTR carbon tiles ever "blow up" ....actually yes.
Remember TNT energy equivalent
1 MJ (TFTR) 0.217 kg TNT
2 MJ (Jelly Doughnut) 0.434 kg TNT
1 GJ (ITER) 217 kg TNT"
http://wsx.lanl.g...1465.pdf

BOOM! haha.
antialias_physorg
5 / 5 (5) Mar 22, 2012
But the absolute worst thing that could happen is that they could EXPLODE in massive fireballs of ignited metal.

Erm..no? How should that happen?

Could this lead to a breach of the containment vessel in a commercial reactor

No. as noted: if the plasma ever comes into contact with the wall it's already
a) out of the confinement field (i.e. your field isn't homogeneous enough anymore and the plasma has expanded to a vastly greater volume than when confined. I.e. it has cooled. Which means: no more fusion). Note in the article how critical confinement is.
b) the ablated material will further contaminate the plasma, thereby stopping fusion if it hasn't already stopped due to a)

There is no cascade, because unlike with fission reactors: not your entire fuel stock is in the reactor. Even if you kept dumping your remaing fuel in there nothing would happen.
antialias_physorg
5 / 5 (5) Mar 22, 2012
And yes: commercial fusion reactors will have to be enclosed by a biological shield (several meters of concrete) - just like fission reactors. Not because they blow spectacularly, but because it IS a nuclear reaction and you are creating betas.

As for that PR tripe you linked to (did you read it: if'you're not lauching all the way through at this piece of PR you gotta be nuts).
Yes: the energies in there will 'melt a ton of copper' (or launch a tomcat or whatnot)...but that's exactly what it will do: If the cooling fails it'll melt the superconductors. Quenching has happened in the past and we know what it looks like. We're not talking hydrogen bombs, here.

Will a failure be expensive: yes. Countryside-destroying: Not in your wildest dreams.
Newbeak
4 / 5 (3) Mar 22, 2012

At any rate you have radioactive thorium in there - which needs to be mined/refine and could be dispersed (by whatever accident or intentionally) - so it's not inherently safe.



I think the important thing is that we need a new way to produce power NOW that will not release more CO2 in the atmosphere,and something that is much safer than light water pressurized reactors.Molten salt thorium reactor designs are safe enough to run WITHOUT a containment vessel,which greatly increases the expense and size of current fission reactors.Fusion research should continue,but a commercial reactor is at a minimum decades away.
TheGhostofOtto1923
3 / 5 (4) Mar 22, 2012
How should that happen?
YOU didnt follow my link. The plasma hits with the force of at least 217 KG OF TNT. If a wall breach occurs cryo coils may be damaged, leading to a quench which could expose molten, pressurized lithium to the atmosphere. Explosions - fire - massive destruction - mass casualties.
As for that PR tripe you linked to (did you read it: if'you're not lauching all the way through at this piece of PR you gotta be nuts).
You obviously skipped the part where it says it was written by G. A. WURDEN, a scientist at Los Alamos National Laboratory.

These things are dangerous. This has been talked about by scientists for decades. 6,000 tons of 'molten' magnets? How fast will they melt? You read about exploding TFTR tiles?

When I was at PPL a journalist from Mother Earth mag tricked one young and naive theorist into talking candidly about these issues, and then published an expose. They do exist and I am sure they will be designed for. Like Fukushima. Or LHC.
Urgelt
not rated yet Mar 22, 2012
Anti,

Otto isn't saying fusion would continue. But the power required in those magnetic coils in any imaginable production version will be large. Lose control, lose your superconductivity, and you might get sun-like temperatures (briefly) in an expanding ball of plasma. Thousands of tons of magnetic coils turning into plasma means a big explosion, even with no continuing fusion from the start of the accident.

There should be the potential to design a commercial fusion generator to "fail-safe," since fusion stops the moment something goes wrong. But we can't get to that stage of engineering, because frankly, magnetic-inertial confinement isn't getting good results, it's terribly expensive, and there is no obvious path to scale it up for commercial use.

Brute force smashing of nuclei together isn't getting us anywhere.
Maybe we need to *seduce* nuclei into joining together. Nuclear catalysis!

If only Vladimir Nabokov had been a physicist. :-)
TheGhostofOtto1923
1 / 5 (1) Mar 23, 2012
Maybe we need to *seduce* nuclei into joining together. Nuclear catalysis!
Anti doesnt believe in the Widom-Larsen theory - the one which NASAs recent patent is based on - either.
http://www.newene...ry.shtml

But as far as hot fusion is concerned, G. A. WURDEN made it clear in his presentation (derived from his scholarly paper) that ITER is being built to understand how to manipulate plasma and confine it indefinitely. In this respect it is an invaluable step toward using material like antimatter... which is what I have been saying all along.

Poor dumb Ritchie is 1/5ing me because he has no idea what this subject is about and this makes him feel insecure. Too bad ritchie. I consistently 1/5 ritchie because I usually DO know what the subject is about.
Urgelt
not rated yet Mar 23, 2012
Otto,

Thanks for the link.

Basic research is good, if we can afford the sums involved in magnetic-inertial confinement to do it. Eh, why not, LHC is even more expensive.

I wouldn't bank on a patent (by NASA or anyone else) as a substitute for evidence or scientific consensus when it comes to determining the truth of an hypothesis. Patent clerks, it turns out, aren't the sterling arbiters of nature's truths that some folks imagine them to be.

Nabokov, alas, would have hated physics. You can't just imagine what is true in physics and proclaim it, as a novelist can do. There are those pesky extra steps involving evidence, replication, and persuasion to take into account.

I'm eager to be persuaded that nuclear catalysis is possible - and a useful source of energy. But I'm not so eager to be persuaded that I'll dispense with evidence and jump straight to a conclusion.

The problem I see with evidence thus far for cold fusion is it's rooting around in the statistical noise.
antialias_physorg
5 / 5 (4) Mar 23, 2012
Otto isn't saying fusion would continue. But the power required in those magnetic coils in any imaginable production version will be large.

Of course. But you always have to consider what will happen. Gigajoules are gigajoules. But gigajoules going into melting copper is something else than gigajoules going into an explosive shockwave. One causes destruction and mayham, the other does not.

The coils at LHC exploded - nothing much happened. Transformers explode - nothing much happens except VERY local damage. Coal or oil power plants produce gigawatts of power - yet when they fail they don't lay hundreds of square kilometers to waste (not saying that coal/oil is great - just showing that its naive to think that something that has the energy of a ton of TNT will blow up like a ton of TNT. )
antialias_physorg
4.5 / 5 (6) Mar 23, 2012
We really need to keep perspective here. Even fission powerplants don't (and can't) blow up with a mushroom cloud. The possible hydrogen explosions don't do anything besides local damage.

The danger from these accidents isn't the explosive energy released (not from fusion, oil, fission, or even gas powerplants - the latter would probably cause the biggest bang)

Fusion plants are safe because they create no danger for the environment at large. At worst you get a destroyed powerplant. Expensive - but not catastrophic to millions of people in the immediate vicinity.

Where fusion is preferrable over fission is this: There's no chance of radioactive fallout. There's no chance of getting into a situation where you cannot even approach the reactor anymore. The thing can blow up - but it can't (in the long run) REMAIN out of control.
TheGhostofOtto1923
1 / 5 (1) Mar 23, 2012
We really need to keep perspective here. Even fission powerplants don't (and can't) blow up with a mushroom cloud. The possible hydrogen explosions don't do anything besides local damage.
Like I said, just qualifying. Certainly not the pfft you and the press releases imply.
When I was at PPL a journalist from Mother Earth mag
Thats 'Mother Jones' mag - subversive leftists and tree-huggers.
Urgelt
not rated yet Mar 23, 2012
Eh, I'm not the arbiter of who's right or wrong, so my opinion doesn't carry any weight, particularly.

But I'll share it anyway. :-)

Otto made the case for a very large amount of energy being dumped in a short period of time during a particularly nasty failure. Anti claims it won't be explosive. Neither has a working fusion reactor design to point to and say, "See?"

Engineering counts. In the absence of a design to examine, we can't really know if it would be explosive or not. But it's certainly imaginable that the amount of energy involved is sufficient to produce a large explosion. What's missing is an understanding of how event energy will be processed.

LHC's coil meltdown wasn't explosive. How will a magnetic-inertial reactor compare to LHC? There's no fusing plasma at LHC, and it looks like the energies in a production fusion reactor's coils will be much, much larger than LHC.

It's all in the design. Careless designs could fail explosively, I'm thinking.
Urgelt
not rated yet Mar 23, 2012
But I doubt we'll ever find out, because I suspect magnetic-inertial fusion is barking up the wrong tree. Too expensive, too finicky for workaday power generation. It will not directly yield a solution to our need for electricity.

It's fine as basic research, though.

Meantime, if scientists can find ways to exploit the weak nuclear force for energy production that are safe, economical and efficient, that's a good thing, too. But that's a pretty darned big "if." We need to see some experimental successes that can be replicated.

Too much in the field formerly known as "Cold Fusion" is going on within black boxes which nobody is permitted to peer into or replicate, not to mention well-documented fraudulent replication claims. This does not inspire confidence, and neither do results which are down in the weeds of statistical noise and measurement error, which has been a problem from the beginning with cold fusion.
antialias_physorg
3.6 / 5 (5) Mar 24, 2012
But it's certainly imaginable that the amount of energy involved is sufficient to produce a large explosion.

What with? Energy alone does not cause an explosion.

You always have to have something that explodes - and even in that case: The amount of energy released would cause damage at the plant - not anywhere else.

As noted: Explosions are NOT why some powerplants are dangerous. Meltdowns, leaks of toxic fuels into the environment, wide dispersal of toxic aerosols during an accident (or operation), posioning of groundwater and soil - THOSE are the dangers of a powerplant.

A fusion powerplant has no chance of any of those - since it contains no such substances.
Callippo
1 / 5 (3) Mar 24, 2012
A fusion powerplant has no chance of any of those - since it contains no such substances.
Fusion plants would generate and handle large amounts of radioactive tritium, it would generate the neutrons which must be shielded with materials, which would gradually become radioactive in the same way, like the components of classical reactors. The large flux of high-energy neutrons in a reactor will make the structural materials radioactive. The radioactive inventory at shut-down may be comparable to that of a fission reactor. The products of fusion will be mostly radioactive isotopes. There are a number of major engineering problems, notably finding suitable "low activity" materials for reactor construction, demonstrating secondary systems including practical tritium extraction, and building reactor designs that allow their reactor core to be removed when its materials becomes embrittled due to the neutron flux.
Urgelt
not rated yet Mar 24, 2012
I wrote: "But it's certainly imaginable that the amount of energy involved is sufficient to produce a large explosion."

Anti wrote: "What with? Energy alone does not cause an explosion."

Yes. What characterizes an explosion versus a nonexplosive release of energy is the speed of release of the energy. The total amount of energy released is only one variable. This is why the engineering design of a working fusion power plant (with its safety features) has to be considered.

I stand by my original point, though. The amount of energy in production amounts of fusing plasma and in magnetic coils to contain it, if catastrophically released in a short enough period of time, will meet the definition of an explosion.

It's a mistake to presume that an explosion requires "fuel" to perpetuate it: fusing hydrogen, or burning natural gas, or rocket fuel, or whatever. All that's needed to meet the definition of explosion is enough energy released very quickly.
Urgelt
not rated yet Mar 24, 2012
It might be amusing to regard Tunguska in our discussion. Tunguska was a classic example of a large, non-sustaining explosion. The total energy released was probably on the order of 15 megatons of TNT, given a generous margin of error around that number (it could have been twice as large, or smaller). There was no sustaining fuel, just a large mass of cometary ice and dust particles slamming into the atmosphere. The comet's kinetic energy was released in a very short time interval. Result: explosion.

In the case of a large production-version fusion plant operating with magnetic-inertial compression and very large superconducting magnets, the energies involved will be big enough to compare with a mid-sized nuclear warhead detonation. If - a big if - the energy is catastrophically released over a very short period of time, it will be explosive. You would not want to be standing anywhere near it if that happens.
Urgelt
not rated yet Mar 24, 2012
Which is not to say that I am predicting that a fusion plant *must* explode if control is lost. Whether or not it will is a function of design.

The energies involved are sufficient for me to *imagine* an explosion. Imagination is probably all we'll ever bring to bear on commercial magnetic-inertial confinement fusion plants. I don't think that particular tree is going to bear economical fruit.
antialias_physorg
5 / 5 (5) Mar 24, 2012

I stand by my original point, though. The amount of energy in production amounts of fusing plasma and in magnetic coils to contain it, if catastrophically released in a short enough period of time, will meet the definition of an explosion.

Every powerplant has a lot of energy in a small space (otherwise it wouldn't be a powerplant). Consider a gigawatt gas powerplant and a gigawatt solar power plant (or windfarm). Exactly the same power. Exactly the same energy contained at any one time in the power producing systems. Can a solar power plant blow up? No - it cannot. Because it has nothing to blow up WITH (no combustibles or fuel deposits that could release their energies uncontrolled)

Fusion needs an ACTIVELY (and VERY) controlled environment to happen (unlike current fission plants which need a moderated environment to PREVENT meltdown)
antialias_physorg
5 / 5 (4) Mar 24, 2012
Even if you were to try and intentionally dump in more fuel to create an 'overload' scenario it wouldn't work. The fusion process is very finicky that way. Put in too much fuel and the whole thing stops.
TheGhostofOtto1923
1 / 5 (1) Mar 24, 2012
Otto made the case for a very large amount of energy being dumped in a short period of time during a particularly nasty failure. Anti claims it won't be explosive. Neither has a working fusion reactor design to point to and say, "See?"
...But otto has a scholarly paper which says that plasma quench would occur with the force of a 500 lb jdam
http://www.youtub...OnTXENzM

(vid posted for antagonistic effect)

-Otto also has also worked directly with physicists who used to talk about this stuff. Otto has also read the Mother Jones article.

Antialias has rosy-colored press releases and Discovery channel tv specials.
This is why the engineering design of a working fusion power plant (with its safety features) has to be considered.
G. A. WURDEN, los alamos scientist, claims in the powerpoint presentation of highlights from his scholarly paper, that plasma disruptions are a potential game-ender.
cont>
TheGhostofOtto1923
2 / 5 (3) Mar 24, 2012
G. A. WURDEN:
"Multimegamp e-beams at energies of ~ 10 20 MeV loose inside of ITER simply cannot be tolerated, and will likely cause catastrophic failure of thin first wall components in exactly one occurrence."

"When Millions of Amperes of runaway electrons are produced as a result of a single disruption, orbiting in ITER, then you have created a huge e-beam welder when they finally impact on something physical."

"...there may be more total energy in the runaways than assumed, on shorter timescales, than this analysis considered, due to back EMF as large runaway currents decay."

"Not only can disruptions cause serious damage to the tokamak, but our lack of control of disruptions causes damage to the credibility of our future tokamak fusion reactors ...and to magnetic fusion energy in general."

-All of which will occur within inches of pressurized molten lithium and cryogenic coils.

Antialias and the press seek to minimize the destruction of a multi-billion $ facility.
TheQuietMan
not rated yet Mar 24, 2012
I would define an H-Bomb as producing an abundance of energy. Not usable perhaps, but you talk as if there were no real examples, and not worth pursuing.

While I haven't discounted cold fusion entirely, most of the people advocating here are delusional. They speak as if there are working prototypes, I would be happy with reproducible prototypes. Thing about the web, you can show anything to be possible, overunity, perpetual motion, and more. Science is a bit more picky.
Urgelt
not rated yet Mar 24, 2012
I'm very much afraid that Anti is ignoring the energies in the system when he concludes that a production version of a magnetic-inertial confinement fusion reactor could never - regardless of design - explode.

Let me try to explain again why no sustaining fuel is required to produce an explosion. (Last time, one for the road.)

Take the LHC. It has superconducting magnets whose purpose is to accelerate charged particles to high speed over a long racetrack. The energies involved in the LHC superconducting magnets are pretty high; sudden loss of superconductivity will cause the energy in the system to suddenly, catastrophically hit resistance and release heat energy. You can get impressively slagged coils.

But the LHC is different from a hot fusion reactor design. You aren't magnetically containing a large amount of very hot plasma, you aren't manipulating just a few particles, you're using much more energy, and your magnetic coils are concentrated in a much smaller area.
Urgelt
5 / 5 (1) Mar 24, 2012
As a consequence, a catastrophic failure has the potential - depending on design - to release much more energy than LHC can do in a very short time interval.

The resulting hypothetical explosion would be dependent purely on energy in the system to be released and the time interval over which release takes place. There is no requirement for a "sustaining fuel." You do not need to add energy from combustion or continuing fusion to call it an explosion, if the initial energy in the system is catastrophically released over a short enough time interval.

It's potentially comparable to kinetic strikes from meteors or comets (though not Tunguska, which was bigger), because of the order of magnitude of energy in the system, which is going to be large.

The time interval might be very short, depending on design, because destabilizing plasma could result in superconducting magnets losing superconductivity from heat, whereupon they will dump their electrical energy very quickly.
Urgelt
5 / 5 (1) Mar 24, 2012
Whether you get merely slagged magnets, or an explosion, is dependent on total energy in the system and the time interval in which it is released.

LHC, lacking a big confined plasma to destabilize and disturb its steering magnets, having its steering magnets spread out over a long racetrack, and having much less energy in the system, can only produce a few slagged magnets, and not from loss of plasma control. It cannot produce an actual explosion (I think). Worst case for LHC is what we've already seen, probably. But LHC's accident does illustrate, on a much smaller scale, that superconducting magnets which suddenly lose their superconductivity will release the energy in the system as heat. Not that this is a surprise to physicists.

Ramp up the energy in the system to much higher levels, confine magnets to the immediate vicinity of fusion plasma, and destabilize the plasma, and the effects may be considerably more dramatic. Explosively so, potentially, depending on design.
Urgelt
not rated yet Mar 24, 2012
It's important to note that the hypothetical explosion is not a fusion reaction. This isn't a hydrogen bomb going off. It's simply a very large amount of energy being converted directly to heat in a very short time interval.

There may be some incidental combustion in such an explosion, but none is required for it to be quite impressive.

Otto is very likely correct when he points out that cryogenically-cooled coils will be very close to the fusing plasma, and thus vulnerable to very rapidly losing their superconductivity in the event that plasma containment is lost due to plasma instability. Whereupon the energy in the coils is liberated as heat. Because the coils are close together, rather than separated by long distances as with steering magnets in LHC, the heat energy liberated from one might destabilize the next in a sort of chain reaction, unless the engineering design somehow precludes it.

It's not a nuclear chain reaction, of course, just cascading failures of magnets.
TheGhostofOtto1923
1 / 5 (1) Mar 24, 2012
More bad news:
"At the rate that our world is burning through helium, we could run out of the gas within 30 years. While that might bring some sad faces to balloon lovers, it could spell disaster for the medical community and other industries.

Indeed, some medical facilities here in Canada are already feeling the pinch of helium shortages."
http://www.ctv.ca...-120324/
Urgelt
not rated yet Mar 24, 2012
Otto,

Uh, no. The article is sensationalist and overstates the case badly.

There is no shortage of helium. What's at risk is a business model, which relies on extracting helium during natural gas production and is unable to ramp up the helium supply to meet contemporary demand. And even there, the article makes unwarranted assumptions, such as that current methods of natural gas production will cease to be economically viable within thirty or forty years and that no other sources, such as methane clathrates, will ever be exploited.

The only true statement in the entire article is that Congress acted to artificially reduce the cost of liquid helium on contemporary markets. The rest is just fear-mongering, probably advanced by people who stand to gain if helium prices rise.
pauljpease
not rated yet Mar 24, 2012
In which point the cold fusion violates the thermodynamics? IMO it's based on the same thermodynamical principle, like the hot fusion or coalesce of mercury droplets, for example. Smaller droplets do always merge into larger ones. Actually, such a merging occurs the more easier and spontaneous way, the larger these droplets are. From this reason we can just expect, the merging of hydrogen with relatively large nickel nuclei will happen easier, than the mutual merging of two protons.


OK, this just DEMANDS a response. Fusion can only occur when two positively charged atomic nuclei interact. Your statement that this will occur "more easier" with larger nuclei neglects the fact that the mutual repulsion scales exponentially with the charge of the nuclei. That is why fusing two hydrogens ( 1) is waaaay easier than fusing a hydrogen and nickel ( 28). Nickel would only fuse under the most insane conditions within a supernova. 28 charge!!!
Callippo
1 / 5 (2) Mar 24, 2012
That is why fusing two hydrogens ( 1) is waaaay easier than fusing a hydrogen and nickel
At the case of nickel you have 28 electrons which do compensate the charge of these protons. The force, in which these electrons are attracted to atom nuclei increases exponentially as well. In addition, during rare but undeniable moments all these electrons may become aligned toward hydrogen nuclei, thus shielding its repulsive force completely.
Callippo
1.3 / 5 (4) Mar 24, 2012
For me it's rather surprising, the people are doing simulations of whole galaxies with millions of particles all the time, but who ever tried to simulate the Coulombic interactions of atoms with 28 electrons?
antialias_physorg
3.7 / 5 (3) Mar 24, 2012
I'm very much afraid that Anti is ignoring the energies in the system when he concludes that a production version of a magnetic-inertial confinement fusion reactor could never - regardless of design - explode.

It can 'explode'. Like a transformer can explode. A car can explode. Your laptop battery can explode. So what? The point is: compared to fission this is safe. The absolute worst case scenario is a lot of expensive tech needing replacement. You wouldn't even have the loca environmental damage that an oil power plant would generate if its fuel were to blow.

As for the "electron beam": how long will that be active? A second? A microsecond until the plasma disperses because the containment fails (because the beam cuts through a superconductor)? 10MW is a lot of power - but over a microsecond that's not much energy.
MorituriMax
3 / 5 (2) Mar 24, 2012
We owe it to the country to understand how realistic this possibility is
I do agree - the researchers of hot fusion are becoming a bit desperate, because the cold fusion is economically way more advantageous, not to say about its scalability. And it works even without expensive simulations. http://www.infini...emo.html
I owe it to all people to understand, how big waste of public money this research actually is.

Of course, why there must be dozens of these facilities around the country already. Oh wait, there aren't.
Callippo
1 / 5 (1) Mar 24, 2012
why there must be dozens of these facilities around the country already. Oh wait, there aren't
For example NASA patented the cold fusion, but Andrea Rossi, who did come first with it still didn't get the patent in the USA. He even has no permission for selling his technology, because it's labeled as nuclear device. You can just speculate and ask why.
Urgelt
5 / 5 (2) Mar 24, 2012
Anti wrote, "It can 'explode'... So what? The point is: compared to fission this is safe. The absolute worst case scenario is a lot of expensive tech needing replacement. You wouldn't even have the loca environmental damage that an oil power plant would generate if its fuel were to blow."

That depends entirely on how much energy is released in a very short period of time.

I admit I am not certain about how much energy will be in the superconducting coils for a production fusion plant to generate magnetic confinement of plasma. We don't have a design to examine. But if coil energy is equivalent to several hundred thousand tons of TNT, and if the design does not prevent the sudden collapse of superconductivity during a loss-of-control event, it's not going to limit itself to a little slagging of machinery.

We must leave it as an open question. We have no engineering design for a production fusion plant, no confirmation of energies involved, no way to examine safety features.
Egleton
1 / 5 (1) Mar 25, 2012
The great hot fusor in the sky produces about 163w per cubic meter. About the same energy density as a compost heap.
Emulating the sun is hardly inspiring.
Egleton
1 / 5 (1) Mar 25, 2012
OK, this just DEMANDS a response. Fusion can only occur when two positively charged atomic nuclei interact

Except for muon catalysed fusion of cause. . and um other undiscovered and totally surprising effects.

Isn't science wonderful? Just when you think you know everything there is to know about everything, something comes along and rains on your parade.
Callippo
1.7 / 5 (6) Mar 25, 2012
Isn't science wonderful? Just when you think you know everything there is to know about everything, something comes along and rains on your parade.
Yep, I do like this aspect of science too. The rock-steady proponents of "right science" are facing bad times today.
Newbeak
not rated yet Mar 25, 2012
The force, in which these electrons are attracted to atom nuclei increases exponentially as well. In addition, during rare but undeniable moments all these electrons may become aligned toward hydrogen nuclei, thus shielding its repulsive force completely.

I'm not a physicist,but wouldn't the high energy nickel atoms be stripped of their electrons long before they fused,and thus not be a factor in the fusion equation?
antialias_physorg
not rated yet Mar 25, 2012
The great hot fusor in the sky produces about 163w per cubic meter. About the same energy density as a compost heap.
Emulating the sun is hardly inspiring.

To be fair: Most of the sun isn't undergoing fusion - and it is only that part we want to emulate (and that part has an energy density of slightly more than a compost heap).
TheGhostofOtto1923
1 / 5 (1) Mar 25, 2012
It can 'explode'. Like a transformer can explode. A car can explode. Your laptop battery can explode. So what? The point is: compared to fission this is safe.
'Explode'. I think it would be somewhere between your transformer
http://www.youtub...=related

-and this here
http://www.youtub...GizBjDXo

-But Im thinking it would be something more like this
http://www.youtub...=related

The absolute worst case scenario is a lot of expensive tech needing replacement.
The absolute worst case is that this would be insurmountable and that hot fusion power would be deemed impractical. But not everybody would be disappointed. Right callisto?
Dug
not rated yet Mar 26, 2012
And what's the smallest star with hot fusion like the sun? How do natural occurrence limits affect the limits of scalability?
TheGhostofOtto1923
1 / 5 (1) Mar 26, 2012
And what's the smallest star with hot fusion like the sun? How do natural occurrence limits affect the limits of scalability?
Im sorry but are you actually asking someone to look this up for you?? Or you just trying to make a point and if so, what is it?
http://en.wikiped...tar#Mass

antialias_physorg
not rated yet Mar 26, 2012
But Im thinking it would be something more like this

Exactly what I'm saying. A bit of tech flying about. No impact on anything beyond the powerplant whatsoever.

Fusion powerplants don't give you all the radioactive baddies.
Remember: In a fission powerplant ALL the fuel is at the site of the explosion/meltdown. And ALL of it is radioactive all the time.

In fusion powerplant only that part that is currently in the chamber has any radioactivity (and the inner walls of the chamber - like in fission power plants). The rest of the fuel can't explode.
That's much, MUCH less fuel going up in smoke - and it's also much less radioactive and likely to soak into the soil as explained before.
TheGhostofOtto1923
1 / 5 (1) Mar 26, 2012
Fusion powerplants don't give you all the radioactive baddies.
Remember: In a fission powerplant ALL the fuel is at the site of the explosion/meltdown. And ALL of it is radioactive all the time.
Yah. We know this AA. Your original point was that fusion reactors stop with a gentle little fizzle. I have shown the world that this is not so, and your struggle to backpeddle does not change this. And by the way a 'bit of tech flying about' in this case is a VERY big deal.
antialias_physorg
not rated yet Mar 27, 2012
The fusion reaction does stop with a gentle fizzle. That's the point. If something (anything) doesn't go according to spec the whole thing gets out of whack and stops doing fusion on a dime. It's the ultimate in passive safety. Not even coal, oil or gas power plants are that safe (because there the fuel storage could, theoretically, blow)

I never said there would be NO damage at all. Everywhere where you concentrate energy you can direct that energy to cause some damage.
But you won't get a huge explosion (and no - not even a hydrogen explosion like at Fukushima).
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
The fusion reaction does stop with a gentle fizzle. That's the point. If something (anything) doesn't go according to spec the whole thing gets out of whack and stops doing fusion
No 275 kg of TNT does not go off with a gentle fizzle.
But you won't get a huge explosion (and no - not even a hydrogen explosion like at Fukushima).
And yes unless these things can be safely designed and operated the potential for a huge quench cascade explosion on the order of Fukushima does exist. I am sorry if your head is too hard to accept this as it has amply been shoved into your face.
Urgelt
5 / 5 (1) Mar 27, 2012
Sigh.

Anti, nobody is arguing that fusion is going to continue after lost of containment. It will stop. There will be no fusion explosion. We all get that.

What you aren't getting is that the energy in superconducting coils will be liberated in an instant if superconductivity is lost.

A production fusion plant will have cooled superconducting coils in close proximity to the fusing plasma. If containment is lost, the plasma will expand out of its confinement and heat the coils, unless the design somehow precludes it from happening. Whatever energy is in the coils will be converted to heat through resistance in the suddenly warmer coils.

The coils will have a lot of energy in them. How much, I'm unsure, but if the magnetic-inertial containment experiments now underway are any indication, then the energy store in the coils for a production version might be sufficiently large to rival a mid-sized thermonuclear explosion.

Without the radiation, of course.
antialias_physorg
not rated yet Mar 27, 2012
the energy in superconducting coils will be liberated in an instant if superconductivity is lost.

Sure I'm getting that. But so what? There are ways to vent the cooling gas (by simply introducing fault lines like we do in current MR scanners) and the coils will bump/melt. We're not talking citywide destruction. We're not even talking builiding-wide destruction. These apparatus don't pose a danger to anyone or anything except themselves.

If containment is lost, the plasma will expand out of its confinement and heat the coils

Quickly cooling itself in the process.

then the energy store in the coils for a production version might be sufficiently large to rival a mid-sized thermonuclear explosion.

The energy in there will be less than what the powerplant can produce (otherwise there'd be no point to building the powerplant). We're not talking nuclear bomb. We're talking small, conventional bomb - at worst. And that inside a cement bunker.
Urgelt
5 / 5 (1) Mar 27, 2012
This isn't the first time this has come up in speculative discussions about superconductivity. There has even been thought put into the idea of superconducting coil warheads, which could, in theory, hold enough energy to produce explosions rivaling or even exceeding thermonuclear warheads but without the radiation. It's speculative, of course, because we can't make portable superconducting coils. But it might become feasible if we can discover ways to produce superconductivity in materials at much higher temperatures, allowing us to dispense with cooling apparati.

High temperature superconductivity is therefore something of a Pandora's box. It could end up being a very dangerous breakthrough as well as a useful one. The barriers to entry for superconducting warheads might be much lower than they are for nuclear warheads, presenting a major proliferation problem - if high-temperature superconductivity is ever solved and can be mass-produced.

Thus far it's just food for thought.
Urgelt
not rated yet Mar 27, 2012
Anti wrote, "The energy in there will be less than what the powerplant can produce (otherwise there'd be no point to building the powerplant)."

You're mixing apples and oranges. The amount of energy in the coils is discreet - whatever is required to generate the magnetic containment fields. It's not really consumed; it's more a construction cost than an operating cost. The energy produced is continuous. What does it matter if you have to charge the coils for a week? Or a month or two? Once you put the energy in, it just races around in the coils, and your fusion plant starts pumping out energy over time.

The economics of fusion power won't depend much on how much energy is in the coils. Bigger variables are construction costs, output and risk.

It's a big economic hit if the damn thing isn't certain to be stable. If the risk of loss of containment is not vanishingly small, it won't be economically feasible at all; insurance and/or liability would eat the project alive.
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
These apparatus don't pose a danger to anyone or anything except themselves.
These apparatuses dont exist yet. It is not yet known whether they can be designed to operate safely.

Lets read it again shall we?

"One of the most serious issues a large tokamak will face is controlling 100s of MJ of plasma energy that can be quickly released in the event of a disruption, whether due to burning plasma issues, or more everyday tokamak physics. The number of full energy disruptions that an armor system in a large tokamak can survive is very small, due to the opposing engineering constraints of rapid heat removal in steady-state, versus designing survivability to transient events."

and

"Multimegamp e-beams at energies of ~ 10 20 MeV loose inside of ITER simply cannot be tolerated, and will likely cause CATASTROPHIC FAILURE of thin first wall components in exactly one occurrence."

IF this cannot be dealt with THEN tokamak fusion is DEAD.
antialias_physorg
not rated yet Mar 27, 2012
No 275 kg of TNT does not go off with a gentle fizzle.

It's not 275kg of TNT. It's the ENERGY EQUIVALENT TO 275kg of TNT. Not the EXPLOSIVE FORCE equivalent to 275kg of TNT.
TNT is designed to give maximum explosive force via increase of volume. Superconductors are not.

Do you have any idea how much TNT energy equivalent it takes to melt one ton of copper wire (and we have a lot more than a ton of wiring that will melt in a quench)?

Here's a link to the energy that the LHC has in a beam.
http://lhc-machin...beam.htm
That's 362MJ. (The equivalent energy content of 50kg of TNT)
Barely enough to melt half a ton of copper.

So if your 275kg of TNT are correct this thing will melt all of 2.75 tons of wiring (without even a pop). We won't even lose all of the wiring on the powerplant that way.
antialias_physorg
not rated yet Mar 27, 2012
For comparison: The Chernobyl desaster produced an explosion of 100 tons of TNT equivalent (in steam - which is very much more akin to an explosive than melting superconductors are). We're talking almost 3 orders of magnitude less, here. AND not explosion but melting. You could probably stand right next to the building without any fear of injury (though, if the Helium is vented you'd talk funny for a couple of seconds).

"Multimegamp e-beams at energies of ~ 10 20 MeV loose inside of ITER simply cannot be tolerated, and will likely cause CATASTROPHIC FAILURE of thin first wall components in exactly one occurrence."

As I said: Yes: tech will be destroyed (and these 'beams' aren't lose but for a fraction of a second). No. This is not the Death Star. You don't punch holes with an e-beam into stuff in fractions of a second - especially not one going all over the place.
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
Anti, nobody is arguing that fusion is going to continue after lost of containment. It will stop. There will be no fusion explosion. We all get that.
For that matter, the fusion reaction stops shortly after a thermonuclear warhead detonates.
Quickly cooling itself in the process.
And heating up many other things immensely.

Well. More cause for concern:

"The explosion hazard associated with the use of liquid nitrogen in a radiation environment in fusion facilities has been investigated. The principal product of irradiating liquid nitrogen is thought to be ozone, resulting from the action of radiation on oxygen impurity. Ozone is a very unstable material, and explosions may occur as it rapidly decomposes to oxygen."
http://www.osti.g...=6547562

Boom.
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
For comparison: The Chernobyl desaster produced an explosion of 100 tons of TNT equivalent (in steam - which is very much more akin to an explosive than melting superconductors are). We're talking almost 3 orders of magnitude less, here.
Plasma plus coils plus molten lithium plus ozone plus steam? plus ?? = MUCH bigger boom.
AND not explosion but melting.
"One problem is, there may be more total energy in the runaways than assumed, on shorter timescales, than this analysis considered, due to back EMF as large runaway currents decay."

...Boom.
antialias_physorg
not rated yet Mar 27, 2012
The principal product of irradiating liquid nitrogen is thought to be ozone, resulting from the action of radiation on oxygen impurity.

Um, yeah. But you ARE aware that the by the time the plasma has eaten through the hull (which I don't even think it has enough energy for) the fusion reaction - and hence the radiation producing process - has long stopped?

I think you're really grasping at straws, here.
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
The principal product of irradiating liquid nitrogen is thought to be ozone, resulting from the action of radiation on oxygen impurity.

Um, yeah. But you ARE aware that the by the time the plasma has eaten through the hull (which I don't even think it has enough energy for) the fusion reaction - and hence the radiation producing process - has long stopped?

I think you're really grasping at straws, here.
Well yeah, cause and effect... which comes first? Does a plasma disruption breach the wall and start the coil quench cascade? Or does a pressurized ozone buildup detonate causing a coil quench cascade and subsequent containment vessel failure, sending an e beam through the building wall and frying antialias the hapless gawking tourist standing outside? Many possible scenarios here.

You are thinking that scientists who posit these things are grasping at straws, not myself and Urgelt who are only bringing their concerns to your attention. See the difference?
TheGhostofOtto1923
1 / 5 (1) Mar 27, 2012
And we are forgetting about the TONS of molten lithium which will be blanketing commercial reactors. Molten lithium is pyrophoric and 'can only be handled under Argon.' It will also burn violently in contact with many other materials, including water. EXPLOSIVELY.
http://fti.neep.w...m851.pdf

BOOM.
Hengine
not rated yet Mar 27, 2012
Did this article just say "only 26 MA" as in "only 26 MEGA AMPS" because that's a hefty current!!!

Energy numbers are so big they're mind boggling.
Urgelt
not rated yet Mar 28, 2012
Let's back up a bit.

We do not have an engineering design for a production fusion plant to examine.

Everything we can think to say is speculative - on *everyone's* part.

There will have to be a very large amount of energy in the system. Making that energy safe from catastrophic release will be a design goal. If they can't make it safe, then magnetic-inertial confinement fusion isn't going to make it to production.

Otto is correctly pointing out that there are risks that will have to be managed in any magnetic-inertial confinement fusion design. If they aren't managed properly, the potential for a catastrophic event is there, depending on the total amount of energy in the system at loss of confinement and other design elements. Total energy in the system at loss of confinement is a number we don't know, because we can't look at a design yet. Nor are the other design elements known to us.
Urgelt
not rated yet Mar 28, 2012
Since those design elements aren't known to us, but we do know that the total amount of energy in the system at loss of confinement is probably going to be very large, it's not reasonable to conclude that a catastrophic explosion is impossible *merely* because fusion halts at loss of confinement.

There's a very real chance that no design will be feasible *because* managing loss of confinement events *will* produce very large explosions. There are reasons to think this could be hard to avoid. But it's all speculation at this point.

Declaring that explosions could not arise out of a production fusion design is as premature as predicting that they must arise out of a production fusion design. It's a fun conversation, but not one in which a winner can be declared.

I've given my opinion. I think magnetic-inertial confinement is barking up the wrong tree. It's useful as basic research, not useful for proving out a production design. If I'm wrong, it won't be the first time.