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Topic: Nuclear Batteries  (Read 35362 times)

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Offline jdurg

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Re:Nuclear Batteries
« Reply #15 on: April 18, 2005, 04:21:43 PM »
Good luck trying to get some Am.  It's fairly well regulated by the NRC and you need certain licenses in order to legally possess it.  (Since it is kind of impractical and pricey to try and get it through smoke detectors a-la David Hahn).  Although, it may be easier to get the actual element than it is to get a picture of it.  At least that's what I've discovered as I've tried to get photographs of these radioactive elements and/or their compounds.   :(

Though I am happy to say that getting depleted uranium is nice and easy.  unitednuclear.com sells nice sized chunks of it stored under mineral oil to prevent the black oxidation that is seen on my turnings.  I plan on getting some more DU once I can be assured that the vial they ship in will fit into my specially fabricated lead-lined box I put together.  Can't wait to get some unoxidized Uranium! :D
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Corvettaholic

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Re:Nuclear Batteries
« Reply #16 on: April 18, 2005, 10:14:11 PM »
Would DU work? I'm gonna guess that the magical word 'depleted' actually means something.

Offline jdurg

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Re:Nuclear Batteries
« Reply #17 on: April 18, 2005, 11:45:44 PM »
Depleted Uranium is uranium metal from which the % of Naturally Occuring U-235 has been lowered from about 0.7% to about 0.2% or less.  U-235 is fissile and is required in high percentages for uses in nuclear weapons and nuclear power.  (Though fuel rods only require about 5% U-235 while weapons grade material requires upwards of 85% pure U-235).  When natural uranium is refined to produce the fissile U-235, it leaves behind a 'waste' product of the non-fissile U-238.  Because U-238 cannot go critical and is simply an alpha emitter with relatively weak gamma rays, the physical properties of the metal can be used.  Depleted Uranium is incredibly cheap, but incredibly dense and pyrophoric when in a fine state.  Because of the high density (~20 g/cc) and the very cheap price, it makes great use as a counterweight where high mass but low volume is needed.  (Tungsten could also be used, but it's MUCH more expensive than DU is).  

Depleted Uranium is also VERY good at blocking radiation.  Yes, it seems kind of odd that a radioactive metal would be good at blocking radiation, but with a very long half-life and relatively weak alpha and gamma emission, the radiation it blocks is far more damaging than the radiation it gives off.  Therefore, many high intensity radioisotopes used in research or for medical uses are housed in depleted uranium containers.  

Because of the high density and easy machinability, DU has found used in munitions for guns.  The incredibly low cost, incredible hardness, and propensity to explode if it breaks apart on impact makes it a very good tool for piercing the armor of tanks and heavy machinery.  In the same way, DU covered in lead and then steel makes very good, very dense, very inexpensive, and very effective armor plating.

Outside of the body, DU is virtually harmless.  The alpha particles won't get through the layer of dead cells in your skin, and the gamma rays are pretty weak.  It's not something you'd want to have lying out in the open so you could continuously expose yourself to it, but it's not going to severely increase your radiation exposure.  Inside the body, however, DU is both chemically and radiologically toxic.  That's because the uranium's alpha particles are now able to get at freshly created cells and cause internal damage.  Plus, the DU accumulates in your kidneys where it causes major renal damage both chemically and radiologically.  Therefore, inhaling the fumes of burning DU is very dangerous, and you don't want any of it getting inside of you.  (This is why there's the big uproar about using DU in military missions.  Sure it's effective at what it does, but all the burning DU and vaporized uranium is easily inhaled by the soldiers and the people living in that area).

One MAJOR reason why DU is carefully watched, however, is because if U-238 absorbs a moderately slow neutron, it will easily be convereted into U-239 which then decays via beta decay to Np-239.  Np-239 has a half-life of about 2.5 days afterwhich it becomes the HIGHLY fissile Pu-239.  So if someone had a source of neutrons and a LOT of time, they could easily create some plutonium.  Thankfully, it's not as easy as putting neutrons into your DU.  You need a good deal of money to safely do the conversions, and any other materials you might need to do this nasty stuff would raise some flags.  (Like if someone went to buy a few pounds of DU as well as some beryllium or aluminum.  It would raise some red flags.  In fact, just trying to acquire large amounts of DU would raise some red flags since it is also used as the tampering device in a nuclear bomb).
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Offline Donaldson Tan

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Re:Nuclear Batteries
« Reply #18 on: April 18, 2005, 11:46:11 PM »
i think depleted uranium means it has definitely much less U-235 than a natural uranium sample. Probably it's the U-238 'waste' from the centrifugal plants
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

Offline jdurg

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Re:Nuclear Batteries
« Reply #19 on: April 18, 2005, 11:49:30 PM »
i think depleted uranium means it has definitely much less U-235 than a natural uranium sample. Probably it's the U-238 'waste' from the centrifugal plants

Heh.  I agree.  (See my post above).   ;) ;D
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Corvettaholic

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Re:Nuclear Batteries
« Reply #20 on: April 19, 2005, 11:36:23 AM »
Something I'm wondering about concerning alpha and beta particles:

Alpha particle: pretty much a helium nucleus and has a positive charge. Big fat particle.

Beta particle: a free spirited electron with an anti-neutrino. really tiny. Negative charge.

Now I'm trying to relate this to flow of electricity, and how to generate a voltage. What if you had a really strong alpha emitter and a really strong beta emitter and they are seperated by some hypothetical perfect radiation barrier. Never mind how you'd do it, but lets say you had a collector for each type of particle. Next connect these two collectors with a wire. Complete circuit? Anode being the alpha emitter, and cathode being the beta emitter? Or am I trying to connect dots that aren't connectable  ::)

Offline jdurg

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Re:Nuclear Batteries
« Reply #21 on: April 19, 2005, 11:52:35 AM »
The thing is, electrical charge needs to be balanced in a nuclear reaction as well as the atomic weights and numbers.  So when a Uranium-238 atom gives off an alpha particle and becomes Thorium-234, that Th-234 winds up having two extra electrons and a negative charge on it.  As a result, it quite quickly will give those electrons away to the helium nuclei which are floating around near it.  With a beta emitter, the same thing is true.  It gives off the electron, but forms an atom with a +1 charge on it.  So eventually, that +1 charge picks up the electron it needs and becomes electrically neutral.  Since you'd have the positive and negative charges in the same area, you really couldn't complete a circuit with it.  (Plus, after the original material decays via beta or alpha emission, it's daughter product may decay via a different manner and hence corrupt your carefully separated charges).  
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Corvettaholic

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Re:Nuclear Batteries
« Reply #22 on: April 19, 2005, 04:24:11 PM »
So that free electron is going to find a buddy before I can convince it to do any useful work. Too bad. Then I need an alternate way of harnessing electricity. What about taking an approach like a RTG? Its just a big fancy thermocouple. Any ideas on how much output I could expect from something like that if it were... lets say... engine size. Yes, engine size  ;D

There's always been the thought on using solar cells, but those absord light in the visible wavelength. Gamma is freakishly higher than that, so the solar cells wouldn't get excited enough to give me voltage. If you slammed a solar cell with alpha or beta, what would happen?

Couldn't really drive a nuclear powered car around town though.

Mr. Pink

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Re:Nuclear Batteries
« Reply #23 on: April 19, 2005, 09:21:50 PM »
(Since it is kind of impractical and pricey to try and get it through smoke detectors a-la David Hahn).

Ahaaa, that book gave me inspiration. you can get smoke detectors by acuiring broken/outdated ones from other people; that how i get my Am

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Re:Nuclear Batteries
« Reply #24 on: April 19, 2005, 09:29:25 PM »
I like that design, that is a LOT like what I was thinking of minus the ZnS. What about trying to directly use beta particles, or is americium 241 a crappy beta emitter? Also, think it'd be possible to get even a couple grams of Americium without raising red flags?

Am241 isnt a beta emitter at all. And as for the a few grams of Am, u wouldnt count on it. It fires off the three times the alpha particles of radium, so a few grams of pure Am would cross over from "dangerous" to "insane". you need very little Am to make a battery. About one hundred UCi should do; they keep about one UCi in every smoke detector.

Corvettaholic

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Re:Nuclear Batteries
« Reply #25 on: April 20, 2005, 11:57:11 AM »
I thought it was only .1uCi of Am in smoke detectors? If thats true, then I need about a thousand of them. Otherwise I only need a hundred  ;D

Following jdurg's flowchart from DU to Plutonium sounds kind of neat, but that is way beyond my ability. At least without dying or growing a third arm. How nifty would it be to use plutonium for the battery? Just out curiousity, is Pu a good beta emitter?

Mr Pink, I really do like your design, but have you looked into other ways of creating a voltage without using visible light? Still using a radio-isotope of course, and not an RTG.

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Re:Nuclear Batteries
« Reply #26 on: April 20, 2005, 08:04:31 PM »
Ya, it is one full UCurie in a smoke detector, so you would need about 100. David hahn had about that, but i hope you take better safety measures than him. By the way, Pu239 also isnt a beta emitter at all, although, Pu240 is. DU is hard to come by, short of going to iraq and picking DU shrapnel out of a dead soldier or from an abandoned Abhrams tank. Tritium is a very good beta emitter, and it MUCH easier to get. Hell, they even sell novelty keychains that contain gaseus tritium. I suggest getting it from a gel or powde, as tritium gel is what they use for some watches and stuff like that. it is in a solid state and therefore easier to control.

I found out that, for non-RTG atomic batteries, they use a beta emitter and use an electrode to collect the beta particles, and another electrode connecting to the radioisotope gives it its charge back. Using the chemists greatest tool, microsoft paint, i have concocted a design...
the lower wire that penetrates into the big blue orb is the one the gives charge back to the tritium after losing electrons by the process of decay. The lead collects electrons and makes a positive charge.
« Last Edit: April 20, 2005, 09:00:52 PM by Mr. Pink »

Offline jdurg

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Re:Nuclear Batteries
« Reply #27 on: April 20, 2005, 09:47:13 PM »
DU isn't that hard to get ahold of.  You just need to know certain people.
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Mr. Pink

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Re:Nuclear Batteries
« Reply #28 on: April 21, 2005, 12:04:51 AM »
u can get U238 from united nuclear here; http://unitednuclear.com/chem.htm at the bottom of the page. Apparantly they have a limited supply, so order soon. dont order beryllium or sometig like that from the same place at the same time; that will raise some serious red flags.

Corvettaholic

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Re:Nuclear Batteries
« Reply #29 on: April 21, 2005, 01:18:15 PM »
I like your MS Paint drawing! That was the direction I was thinking but couldn't really explain it! Since Americium is an alpha emitter, this design won't work though correct? Or would it? Collect a nice big positive charge on the "out" lead, and will electrons flow out from the "in" lead? Maybe tritium will just be easier.

Lets say you have element 1 with a halflife of 1000 years, and element 2 with a halflife of 1 year. Both are great beta emitters. Element 2 would work much better as a battery because it only has 1 year as opposed to 1000 to dump off all those beta particles, right? Think there's a better beta emitter I can use other than tritium? Also, where would I find how "big" or "heavy" 1 curie of whatever is? I'm guessing 1 curie of tritium could weigh more/less grams and be so many centimeters wider/narrower than 1 curie of plutonium.

Mr. Pink: has that design of yours been tested before? It sure looks good to me! Oh, do you mind if I borrow your MS Paint picture and show it to the guys on the high voltage forum?
« Last Edit: April 21, 2005, 01:20:06 PM by Corvettaholic »

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