h a l f b a k e r yThe phrase 'crumpled heap' comes to mind.
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Enriched uranium
Low(er) cost uranium enrichment by combining plasma sputtering with MS separation | |
Would it be possible to develop a low(er) cost method of uranium enrichment by combining standard semiconductor PVD methods with ionic separation by means of mass spectrometry?
Step 1: A uranium target is sputtered within a plasma, using standard DC discharge or e-beam techniques. A mixture of isotopes
boils off into the Ar plasma.
Step 2: a DC bias is applied *horizontally* to the U target. The lighter U235 isotopes are accelerated more rapidly by and toward the cathode than the heavier U238 isotopes. Under the influence of gravity the two isotopes follow separate ballistic paths (mass spec separation). A spatial filter divides the species.
This method also has the incidental side effect of building up the enriched U layer as a thin film, if desired. Other than an exotic application as an X-ray mirror I have been unable to find material on uranium thin films, however a few possibilities do come to mind:
1. micro reactors and micro nuclear explosives
2. applying U-films to a pair of mating piezo/electrostrictive surfaces
3. focusable X-ray optics (!!)
4. X-ray interferometry!
5. evanescent coupling of X-rays through a thin film X-ray mirror could provide the shortest atomic-scale probe ever developed
What is Mass Spec
http://www.asms.org/whatisms/
a description of how mass spectrometry works [hazel, Oct 17 2004, last modified Oct 21 2004]
another MS page
http://hto-b.usc.ed...metry/tutorial.html
[hazel, Oct 17 2004, last modified Oct 21 2004]
Babelfish
http://babelfish.altavista.com/
For Pericles. Select language option Gobbledigook to English [FloridaManatee, Oct 17 2004, last modified Oct 21 2004]
Uranium enrichment
http://www.uic.com.au/nip33.htm
[kbecker, Oct 17 2004, last modified Oct 21 2004]
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Annotation:
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Not suitable for bulk processing, I'm guessing. |
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sounds nice...er.... um.... whatever this is about. do you know where I can download a quick translating program, anyone? |
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So - this isn't a fortified breakfast cereal? |
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For the non chemist, in mass spectrometry, ions are separated according to mass. These ions may come from fragmenting an organic compound - often in conjunction with some form of separation (chromatography) - or (in this case) by bombarding a thin film of atoms with a laser or a beam of electrons, causing them to 'sputter' off being ionised in the process. They are then separated according to their mass, usually using a combination of magnetic and electrical forces. |
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Gravity won't separate sufficiently, unless you have a flight tube 1km long. You'd need to use magnetic and/or electrical forces to act on the ions (ie magnetic sector or quadrupole instruments). The major problem is the quantity of sample which could be separated (pretty damn low). Also, as you say, is there a need for thin film U? |
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The sound of an uranium particle beam passing way over my head. |
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US forces used uranium particle beans in Iraq, didn't they? |
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Of course, the particles were about 140mm long, and 30mm diameter. |
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I wish I knew enough about the topic to even understand the concept... |
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You will need a real expensive spectrometer to separate isotopes that are only a few % different in mass. If you want something "low cost" you anyway should do chemistry in big buckets (link). |
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I thought it was the US Justice Department that was going to force MS separation. They didn't say anything about plasma sputtering, but Bill's testimony might suffice. Just leave the Office and Explorer divisions intact, OK? |
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[laserider] isn't that far off a practical method, actually. The technique is to use a plasma source to ionise a continuous -feed uranium wire ( a bit like a MIG welder) and then feed the resulting inon beam into a Quadrupole mass spectrometer. This separates the ion stream and you select the DC/RF ratio for the transuranics. However, that won't perform isotope separation. So the uranium ion beam is collimated and accelerated by a set of intermediate plates, then fed into a second quad tuned for high end isotope separation. You can get incredibly pure U235 from the far end of the second quad, but the processing rate is low compared to a gas centrifuge (which has the advantage that it can be mainatined with a hammer) and it uses a LOT of energy to keep the plasma going and pump the system (although it can work at realtively low vacuum, maybe 10-3 or 10-4 Torr). |
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I used to work on this stuff. We did Protium/Deuterium/Tritium separation too, and since hydrogen's a gas at STP it needs a lot less energy and the processing rate is much higher. |
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Zanzibar: "particle bean"? |
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"Because you know when you've bean hit by one", of course. |
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Thank you, 8th of 7. That was precisely the feedback that I was looking for. Altogether I'm not sure I agree with the thread of comments on the --necessarily-- low productivity of isotopic separation by mass spec. We're typically used to seeing mass spec instruments configured purely for analysis of micro sample sizes. 20kW - 100kW power supplies aren't all that expensive in the larger scheme of things. And the wire feedstock idea is neat, simple and robust (MIG torches are pretty low maintenance). |
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I'm surprised by the amount of graffiti comment that accreted around my original posting. For those who have lamented that they don't know enough about the technical details to make sense of the kernal of an idea contained therein, here follows the best translation(s) that I can offer: |
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"I call heaven and earth as witness today, that I have set before you life and death, blessing and cursing; therefore choose life, that both you and your descendants may live..." --Deut 30:19 |
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"...on the pedestal these words appear:
'My name is Ozymandias, King of Kings:
Look on my works, ye Mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away. "
--P.B. Shelley |
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While you're at it, [dag], put my name on the "people who know about isotope enrichment and now wish they didn't" list. |
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Is it a good idea for ideas like this to be posted where any tin-pot dictator or other rich terrorist can decide to try them out? I'm not saying the ideas should be suppressed; they merely should be taken to the appropriate organizations that are already entrusted with similar ideas (nuclear power notions to an energy agency; doomsday weaponry to a military agency, etc.). There ARE times when confidentiality is a virtue, aren't there? |
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On the other hand, I think this idea is both baked and not as useful as the author hopes. If I recall right, the original "Little Boy" A-Bomb used enriched uranium that had been obtained via mass-spectrometry equipment -- but not using PVD -- because the Oak Ridge gas-diffusion enrichment plant (designed to produce large quantities of enriched U-235 more cheaply than MS) was still under construction. Later enrichment techniques, such as those involving centrifuges or lasers, are considered to offer even more cost savings -- but I'm obviously not going to be describing them.... |
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/tongue-in-cheek
enriched uranium plated golf clubs? What happens when Tiger Woods gets one of these and smacks a ball hard enough to drive the coating to critical mass? Micro-nuclear explosion on the club face drives the ball (or what's left of it) to hypersonic velocity, breaking all records for longest drive!
/end tongue-in-cheek |
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[Vernon], don't lose any sleep. The Bad Guys aren't out on the Internet, Googling for "Make your own A-Bomb for fun and profit". |
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They just go and buy the technology from the French. |
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Well, Uranium-238 decays to Thorium-234 by alpha/gamma emission, so you'd be safe on the "neutron emission" clause...... |
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I had an idea of using electropheresis to enrich Uranium on a small scale. Of corse you would have to change the viscosity of the ore to something such as hydrogen to uranium dioxide (UO2). Plus you would have to rig up a special electropheresis machine as well. You dont want the Uranium stuck in gell lol. What does everyone think? |
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I think electrophoresis would work in principle, but not as well as gas diffusion, for separating U235 from U238. Remember that the mass difference (even before adding on other atoms, to make an appropriate molecule for electrophoresis) is 3 out of 238. Most organics subjected to electrophoresis have much wider ranges of molecular masses. Also, you would have to be very choosy about the molecule you did construct from uranium, because you don't want any other atoms that have multiple isotopes. In fact, any organo-uranium molecule is automatically handicapped by the fact that natural carbon comes in C12, C13, and C14, hydrogen comes as H1 and H2, oxygen comes as 016, 017, and O18, nitrogen comes as N14 and N15... and so on. Meanwhile, natural fluorine only comes as F19, so the gas diffusion process uses uranium hexafluoride, meaning that the isotope separation process can focus on the mass difference between 6*19 +235 and 6*19 +238 only. |
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Now, all is not lost for electrophoresis, since uranium hexafluoride is a liquid at room temperature (has a low boiling point, easy to make gaseous), and so might be directly influenced by electric fields. But this is DANGEROUS stuff! -- Not the radioactivity of the uranium, but the results, because every time a uranium atom breaks down, it turns into some other atom, and that atom does not make a hexafluoride. Thus a low level of released and highly toxic fluorine will always be present.... I don't recommend any experimentation along these lines! |
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Dam Vernon, u a player pimp. I see what you are saying about the isotopes of the post electropherisis molecule and the dangers of hexafluoride but easy enrichment on a small scale seems a little hard with the gas diffusion process. I think the key would just be to make the approiate molecule. Perhaps something along the lines of cadmium, which could also assist the fission process.. Perhaps The best rout would be to find a pure isotope of an element to use as a solivant. |
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For the small scale, mass spectro-sorting should be sufficient. Note that the original Idea here suggested MS being used for the large scale, and that didn't go over well. But for the small scale, no problem. |
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[laserider] posted this idea and two annos in June of '03 and was never heard from again. |
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Let that be a lesson to all of us - he's probably languishing in Guantanamo ;-) |
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Or enjoying the benefits of having the most highly paid job in the whole of North Korea. |
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