Subject Explosive Fusion (Without Fission Trigger)???
Posted by Stephen Packard on 2007-12-01 14:44
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Quick question: I have long heard of attempts at a "pure fusion" bomb as a means of reducing fallout, but my understanding is that all the research has indicated that it is not possible to do so, with current technology, and maintain a reasonable size for a weapon.
However, I am wondering if it would be possible to trigger a large amount of explosive fusion in a non-weapon device, which would not have to be delivered by air. Think Operation Plowshare, which determined two things: 1. Nuclear explosions are great at moving a lot of earth to create mountain passes or harbors 2. They produce way too much fallout to do this in any kind of safe or environmentally responsible manner.
However, if a pure fusion device were detonated, and could be encased in a large amount of boron, then perhaps these aims could be achieved with little or no fallout danger.
Could this reaction be triggered by something such as a large chemical laser or very large banks of capacitors? Or even conventional explosives??? |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Steven Sesselmann on 2007-12-01 20:45
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Stephen,
Hmm, I have thought about this too, and I think (95%) I know how it could be done, at least using D+T. I am however not prepared to disclose my idea here.
If one could successfully use such a devise to create a mountain pass, I do not know where one would place the Boron?
Steven |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Todd Massure on 2007-12-01 20:59
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They are planning to detonate a SMALL amount of DT with lasers at the NIF facility. It's mostly if not entirely meant to do research for nuclear weapons without doing full scale underground testing. There's that small possibility that it could lead to something more as far as power production.
Todd Massure |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by falstaff on 2007-09-10 20:57
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Todd Massure wrote:
> They are planning to detonate a SMALL amount of DT with lasers at the NIF facility. It's mostly if not entirely meant to do research for nuclear weapons without doing full scale underground testing.
That's all it ever can do, at one moment, small amounts. It cant scale up for any kind of large explosion. The energy incident on the surface of the fuel capsule has to be a significant fraction of what is going to be released by way of fusion reaction (for any known scheme). Thus, if you want H bomb out you need A bomb in.
>There's that small possibility that it could lead to something more as far as power production.
It looks pretty good for detonation & net gain burn per pellet, but I seriously doubt they'll contribute to any practical power production: they're just not doing the required work for capturing the power while protecting the optics for any practical device. And thats still neutron power BTW, a waste of time IMO. Thus, its a $4B hydrodynamics and high power optics experiment.
Falstaff |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Tom Ligon on 2007-12-01 23:04
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Not Plowshare. Maybe Plumbob or Orion. The Orion program was inspired by a shot called Pascal-B. A 300 ton yield detonation in a shallow well vaporized a concrete "collimator plug", the debris from which shot up the well and kicked about a 1-ton steel cap plate to about 6x excape velocity! Looking at the Orion schemes, they always wanted to coat the bombs with "reaction mass", but the reaction mass they described was always a good moderator like polyethylene. Also, the pusher plates were typically coated with graphite. So from this I gather that the main kick from these things is the neutrons, and they're doing all they can to soak up that KE in recoil reactions.
Any of the neutron-producing fuels needs to do this to avoid neutron-activating whatever you're blasting.
A sufficient quantity of antimatter (not a whole lot, but how much can you buy in a bottle these days?) might make a nice trigger. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Stephen Packard on 2007-12-01 23:53
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Well the reason I had mentioned boron would be to reduce the possibilities of additional fallout through neutron activation of materials by the fusion. This may or may not be a real problem. Given boron is an excellent neutron absorber, I figured one might dig a large hole and fill it win tons of borax or something similar and place the explosive in the center of it. Then run wires or a laserbeam channel or whatever else need be to the powersource for triggering the reaction.
And as far as antimatter.... I doubt well be able to make enough of that for anything this scale any time soon |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Steven Sesselmann on 2007-13-01 01:59
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Yes, obviously the Boron would be placed there to absorb the huge neutron flux, but for that to work, the neutrons have to be slowed down enough so that they can be captured by the boron, and all that has to take place before you blow the whole thing apart. I guess however that the nuclear detonation is that much faster than any physical movement of matter, that it might just work..
Placing the fusion charge in the middle of a large water tank or oil tank, then surrounding the tank with Boron might be a method.
In the instant the fusion reaction runs away, the oil/water will moderate the neutrons and probably vaporize instantly, and as the shock wave travels outwards some of the neutrons may be captured by the Boron mantle.
Probably not something to test in a suburban area.
Steven |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Richard Hull on 2007-15-01 09:06
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Back to the original question.
It begs a parallel question. How are you going to get the pure fussion fuel to burn? This answers, instantly, your question. You can't get it to burn............. Thus, no pure fusion explosive or explosion is possible.
You just gotta' have that A bomb to warm things up. A true, functional, thermal fusion reaction that works! It demands the ancient, stored, potential energy locked in the A bomb's fissionables to light off the near impossible to burn, instantly quenching, fusion fuels.
You just don't simply DO fusion. It is a reaction that just doesn't want to go or stay going outside of gravitationally locked, ultra dense, stellar cores. Even these are pitiable fusion engines. Blessedly so, I might add.
Richard Hull |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Stephen Packard on 2007-10-02 03:34
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| Agreed entirely. The fusion weapon is not simply a batter of setting off the fusion reaction with a fission tigger, the fusion will not be able to propagate fast enough to self-sustain in such a situation and it will barely get going. Hence, the teller-ulam design where you have a fisson "spark plug" surrounded by the fusion fuel and then a casing (sometimes also fissil). Fission gets things going.. causes fusion.. flood of neutrons...more fission... heats the fusion fuel... |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by falstaff on 2007-09-10 21:47
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> You just don't simply DO fusion. It is a reaction that just doesn't want to go or stay going outside of gravitationally locked, ultra dense, stellar cores. Even these are pitiable fusion engines. Blessedly so, I might add.
You might let that one go. As Ive said before, it depends your star. Anywhere from 80W/M^3 (your star) to 10^24W/M^3 (my star  |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Richard Hull on 2007-10-10 10:15
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The upshot is my star...your star, we can't duplicate either in either class and have them run as long. No fusion future.
My star will outlive your fast burner star. We are just lucky we have my star nearby.
Fusion is the energy of the future and it always will be.
Richard Hull |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Duane Oldsen on 2007-28-05 05:57
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The Question of Pure Fusion Explosions Under the CTBT
http://www.princeton.edu/~globsec/publications/pdf/7_2Jones.pdf
Explosively-pumped Flux Compression Generators driving a
z-pinch look good for driving a pure fusion reaction, and seems
to be making the nonproliferation people nervous.
Duane |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by falstaff on 2007-09-10 21:40
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Duane Oldsen wrote:
> The Question of Pure Fusion Explosions Under the CTBT
> http://www.princeton.edu/~globsec/publications/pdf/7_2Jones.pdf
>
> Explosively-pumped Flux Compression Generators driving a
> z-pinch look good for driving a pure fusion reaction, and seems
> to be making the nonproliferation people nervous.
>
> Duane
Nah, nothing there for any kind of mass destruction. Car bomb beats anything under consideration, as the authors ~acknowledge. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Duane Oldsen on 2007-09-10 21:46
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falstaff wrote:
> Nah, nothing there for any kind of mass destruction. Car bomb beats anything under consideration, as the authors ~acknowledge.
(Shrug)
Stack it, Teller-Ulam-Sakharov style. Fusion-fission-fusion-fission...
IIRC, there's no theoretical limit to how many stages you can pack
into a Teller-Ulam device.
See F. Winterberg's work for fusion-fission hybrids. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by falstaff on 2007-09-10 22:05
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> IIRC, there's no theoretical limit to how many stages you can pack
> into a Teller-Ulam device.
Yep thats my understanding, no limit for fusion bombs (unlike fission bombs which fly apart above a certain size). It does appear there was a practicality limit. That is, an explosion above some megatonnage would have just punched a hole in the atmosphere and vented into space, ala a giant chimney. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Stephen Packard on 2007-21-02 10:33
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| I realize this would not have much in the way of "peaceful" uses, but is it possible a pure-fusion explosive could be triggered by the impact of a reentry capsule from a ballistic missile? The kinetic energy of such weapons is quite large. Perhaps if the fusion fuel was well contained within a tungsten capsule and designed to compress on impact? |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Javier Lopez on 2007-22-02 03:28
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I think you would need 200 km/s, only railguns would speed up enought.
Ballistic missile (steel, lead, uranium) is like butter when comparing to nucleus repulsion.
What will be utility of ballistic missile after Global Power Down due oil production collapse? |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by marvin minsky on 2007-21-02 17:55
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| just remember that when using explosives for a trigger, you need to stage the explosives so that you have increased energy density with each detonation. You focus something like magnetic energy into a smaller and smaller space with each congruent explosion. The underground explosion wouldn't need a boron liner, for the initiation you would need lithium deuteride with some tritium to just get it started, upon ignition the fusion flame will convert each gram to 21 thousand tons of tnt. It can easily be plain deuterium after fusion ignition in lithium deuteride. The excess neutrons are absorbed into the soil, with very little residual radioactivity. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Anthony Webb on 2007-09-10 16:51
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During WW2, scientists here in the UK tried to do this, using a sphere of cyclonite (RDX), symmetrically detonated to implode a spherical core, containing Lithium Deuteride. Nothing happened: I think the pressures and temperatures reached were too small by at least 3 orders of magnitude. Just as well, really
Tony Webb |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Mark Rowley on 2007-09-10 21:40
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Anthony,
I never knew about this experiment. Where did you get your information? I would really like to read more if its available.
Mark Rowley |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Digix on 2007-10-10 08:58
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To make fusion explosion it is vital to compress deuterium many times. I am not sure how much but no less than 10 times. How anyone can take for example piece of ice and compress it 10 times?
the only way to do that is some other nuclear explosion.
without compression fusion will not sustain itself.
first fusion bombs failed for same reason and in first Russian fusion bomb prototype(layers of uranium and deuterium) fusion provided only few percent of energy. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Anthony Webb on 2007-10-10 16:54
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Mark- I can't remember where I read that, but it was in one of several books about research in the UK during WW2 - possibly "Most Secret War", by Jones. If it had worked, we wouldn't be worrying about rogue states getting the bomb, but about teenage street gangs!
Tony Webb |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Anthony Webb on 2007-30-10 19:25
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for Mark Rowley
Those fusion experiments during WW2- they weren't in the UK, they were in Germany. They tried imploding hollow silver spheres containing D2 by symmetrically detonating a shell of high explosive round them. The idea was that, a sphere of molten silver would be created, and as it imploded it would also get thicker, so that the infalling inner surface would reach a phenomenal speed, possibly compressing the gas to fusion pressures / temperatures. Nothing Happened (fortunately). If the Nazis had got hold of nukes, the world would probably have been deprived of me! I think that the cushioning effect of the gas would interfere with the process, and also that at high pressure the inner spherical surface would be distorted in a chaotic way, reducing the effect. Now, if they'd used evacuated spheres, with a bit of LiD supported at the centre....
This information is from "The Virus House" by David Irving, pub. by William Kimber of London, 1965. hardback, pp. 193 - 7. Irving is not popular at present, because of his nutty ideas about the holocaust, but I think that this early book about the German nuclear program in WW2 is reasonably accurate- it certainly reads as if well- researched, and is quoted in other works, e.g. by RV Jones. He also mentions that other countries tried this after the war, so I expect we had a go.
Sorry about the delay in replying, the local library took some time finding the book for me. |
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Subject Re: Explosive Fusion (Without Fission Trigger)???
Posted by Richard Hull on 2007-31-10 13:55
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This is a superb book! It probably tells more about the efort from the german side than any other. Certainly the Farm Hall reporting and the early history of the prewar German-French-Italian work and mistakes prior to fusion's discovery is covered better than most works ever dream of reporting.
I can see why this older book is referenced widely.
I recommend it heartily. A superb piece of history, right up there with "Hitler's Uranium Club" and the Rhodes works.... And, it is free!
Richard Hull |
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