Chemical Forums
Specialty Chemistry Forums => Citizen Chemist => Topic started by: Corvettaholic on April 08, 2005, 12:21:33 PM
-
After a lot of googling, I've got a pretty good idea of how a simple nuclear battery is supposed to work. The way I understand it, is have some radioactive element/compound just sitting in a lead box. Inside said box, you have some el-cheapo solar panels or maybe a diode. If using solar panels, would the beta radiation given off allow the panels to generate a voltage? Some company called Betavoltaic seems to think so, but I don't think they have a working model. If you have a simple PN junction, when you slam it with beta particles (or was it neutrons?) it would add more holes to the junction so electrons could actually move, and they WILL move generating a voltage.
Is this stuff just conjecture, or is this actually possible? If its workable from a redneck engineering standpoint, I'd like to scoop all the goodies out of a bunch of smoke detectors, stuff it in a box and get some radioshack solar panels. Cram those in the box too. Put 2 in series so I should get 3V, and stick the wires on an LED. This LED should be lit for the halflife of whatever I stuff in the box, right? Unless this idea doesn't even work in the first place. I'm leery of those "cheap, revolutionary energy sources" I hear about, hence this is why I ask!
-
the gist of harnessing nuclear energy is converting radiation energy into electricity.
isnt beta radiation a stream of electrons? it happens when a neutron in a nucleus decays to form a proton and give out an electron in the process. the new proton remained in the nucleus. there's no fission or fusion in the process.
the nature of the radiation (alpha, beta or gamma) depends on the radioactive element inside the lead box. your description suggests that the electrons released from the radioactive element hits the semiconductor and create a current. however, the idea of having a metal box to contain ions is dodgy. ions are unstable at ambient condition. Moreover, ions normally occur as an ion-pair where two oppositely charged ions group together in gasesous state to balance each other charge. there's no source of anion available to balance the formation of positive charge, if the electrons released are being directed out of the box through an electric circuit.
-
They already make "nuclear batteries". There are a great number of people walking around this Earth right now who have some plutonium imbedded in their chest. For these people, their pacemakers are powered by small plutonium batteries which should last their entire lifetime.
-
i dont think it's beta radiation i could be wrong. after-all, i have limited knowledge on nuclear science.
-
Approximately how much Pu is in those batteries, is it present as a speck of Pu metal?
That would be a neat addition to a periodic table collection 8)
-
So pacemaker wearer-ers already use this idea. Cool, it works. Now where would I find out how to scale that up in size? The interim goal here is the "forever LED". Well not forever, just for the halflife of whatever I use. I obviously can't get plutonium. Is there a special section of webelements that I should look at to see which radioactive element would suit my experiment the best? My mom would love some everlasting garden lights for mother's day, and I want a nuclear battery. Seems like this goes hand in hand ;D
EDIT:
I was just browsing webelements again, and I ran across Actinum and Radium. Both are very bad for you. Webelements told me little other than they are "radioactive". Sometimes I got as far as some elements are good at putting out alpha (heavy, positive), or beta (lightweight, negative), or gamma (will shoot through a yak). For battery purposes, I want beta since I equate negative with electrons. I'm going to go out on a limb and say that I most likely can't buy any of those fun elements. So for experimental purposes, smoke detector supplied americium will have to do. Webelements said that stuff is a good gamma emitter too though, which scares me. How much gamma is too much?
-
Cassini, Voyager and Pioneer probes used a nuclear battery system called Radioisotope Thermal Generator (RTG).
RTGs are essentially a thermocouple attached to an atomic material, (generally low grade, equivalent to the energy released by a microwave over or less) that slowly decays, releasing a controlled amount of heat. The thermocouple converts the heat directly into electricty. Thermocouples are not efficient for large amounts of heat energy so they can't replace actual nuclear plants.
-
Gamma radiation is one of those things where if you can reduce your exposure to it, it's good. I guess it all depends on the energy of that gamma radiation. Look at Rhenium-187. It emits gamma rays, as do most radioactive isotopes, but they are PATHETICALLY weak. As a result, it poses no danger. Gamma rays are the result of the nucleus of the decomposing atom 'readjusting itself', so to speak. The particles inside move around and form a less energetic state, and that excess energy is shot off as a gamma ray. It is really difficult to find a radioactive isotope that doesn't emit gamma rays. Also, the only real way to block gamma rays is with lead metal, and putting lead metal into the ground isn't a good thing to do. (As the acid rain will slowly corrode the lead, and you don't want any lead being taken up by any plants or vegetables in the area). Another thing you have to remember is that when dealing with radioactive isotopes, you have to be wary of criticality. I'm fairly certain you wouldn't be going to that extreme, but if you were to put too much of one substance in too close of an area, you could have it go critical and that would be bad. ;D
-
I thought only Plutonium and Uranium-235 could go critical? Will other elements work with fission too, and do they have the same chain reaction? Never heard of other ones that do it. I've looked into RTG's, but from everything I've read they don't scale down very well. Only good for space probes and stuff like that. I've got a lot of military duty ahead of me this coming month, but when I get some free time I'm going to give it a go with americium and see what happens.
-
ANY isotope which decays by emitting a neutron (I.E can be fissioned) can go critical. Neptunium can go critical, Uranium-233 can go critical, thorium can go critical, americium can go critical, I believe, and there are many more.
-
:o
Didn't know that. Being the case, I would imagine that anything that has the capability to go critical, and therefore be good for my battery, is also highly regulared. Meaning, I can't get it easily. Further into that though, means I'm stuck harvesting the junk from smoke detectors. Are there any goodies I could glean from medical equipment besides high powered transformers/caps or laser tubes? ASU (arizona state) has a surplus area where they get rid of all sorts of goodies for cheap! Also you can get neat stuff through government liquidation.
EDIT:
About the critical thing of americium... I don't want that to happen. I assume every element is different in how much is needed to form a critical mass. Suppose I could have multiple small cells so the stuff doesn't get close enough to be considered critical. I'm going to assume going critical shouldn't be a worry with the very small amounts i'll be working with?
-
Exactly. To go critical you generally need a large amount of the substance. You need around 10 kg of Pu to go critical, though amounts as low as 6 kg can go critical if the bomb-maker is insanely good. Neptunium takes about 34 kg to go critical, and basically, if you have enough of an isotope for it to go critical, just being near it would irradiate you to death.
-
So if I die, then I know I had too much! It's failsafe.
From all your suppliers for your element collection, do any of them sell anything I could use for the battery? I browsed the link section, all the stuff I looked at in webelements... they didn't have. Probably for good reason. So is there any hope of a legal channel to get what I need?
-
i wouldnt worry too much about americium 241 (im assuming that's what you'll be using becuase of its availibility) because if you got enough of it to make a critical mass, putting you hand within the range of the alpha radiation would instantly give you a radiation burn. If you some how do acuire enough radioactive material ("hello, chemical supply store? i need about 50 kg of plutonium, preferably of reagent grade") to pose a neutron hazard, i recommend alternating peices of you material with peices of cadmium.
Below (or perhaps above, i dont know where this attachment is ending up) is my plan for a nuclear battery. First, the Americium emits alpha radiation, which then hits the copper-activated Zinc sulphide, emitting a glow, just like in radium watches. Because the Americium salt and the Zinc salt are in a mixture, almost all of the alpha radiation emitted by the Am hits the ZnS, making visible light. The visible light then hits a sillycone (i like spelling it that way) solar panel, making energy. The quarts is there so that visible light from the Am and ZnS hits the sillycone, but not alpha. This is a design (but they used a more sane alpha emitter) that is used by some for small electronics that barely use energy, such as a watch, or a pacemaker, or something like that. And also, they didnt use silicone solar panels, they simply used a sheet of silicone with a transparant conductor sandwiched between it and the quartz.
By the way, on the subject of solar panels, a company is now developing a new solar panel that not only absorbs infrared, red, yellow, orange, and green, as silicone panels do (did you notice that they are blue? its becuase they reflect blue, these ones are black), but also some ultraviolet, making lots and lots of electricity. It is also cheap and easy to make, and can even be painted on to a surface.
EDIT: Turns out it's below.
-
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?
-
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
-
Would DU work? I'm gonna guess that the magical word 'depleted' actually means something.
-
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).
-
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
-
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
-
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 ::)
-
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).
-
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.
-
(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
-
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.
-
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.
-
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.
-
DU isn't that hard to get ahold of. You just need to know certain people.
-
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.
-
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?
-
1 Curie is the amount of radiation given off by 1 gram of pure Radium-226, I believe. 1 Curie is equal 3.7x1010 disintegrations per second (Becquerels). So you can get a rough estimate of the mass that a curie of a substance would require based upon it's halflife. If something has a half-life of 10 years that means that if you had a 2 gram sample of it, after 10 years, or 315532800 seconds (taking into account the two leap-years that would occur), you would have one gram left. So let's say this mystical isotope has an atomic mass of 140 grams per mole. One gram of that would be equal to 1/140th moles which would equal about 4301428571428571428571 atoms that disintegrated. Divide this by the number of seconds that elapsed and you get 1.3x1013 disintegrations per second. So your sample would have an activity of about 368 Curies per gram. Now this isn't an absolute method for calculating the amount of curies based upon mass, but it gives you a good idea. (Now I'll go back and check all my math and logic and make sure that everything is correct).
-
tritium is probably the best for a nuclear battery. it has a half-life of about 20 years, so it has a long enuf life to be practical, but it shoots off enought beta to generate a good charge. Get some sort of gel, wax, or at least something chemically bonded to the tritium, so you dont have to deal with gas. If you must have gas, house it in glass, because although plastic isnt very gas permiable in air, tritium is so small, it will simply slip between the plastic molecules. And sure, you can post it on the HV forum. Oh and speaking of HV, do u know where i could buy a Van De Graff generator not from united nuclear?
-
Tritium has a half life of 12 years, and although it's a beta emitter, it's a fairly weak one. (The beta particles don't have a heckuva lot of energy). If you were to use a tritium compound, you'd lose a good portion of the energy as the beta particles would hit other atoms in the compound/matrix and wind up going bye-bye. Thus, you'd create a mixture of positive and negative charges within the chamber itself and completely destroy any type of circuit.
-
ahhhh, makes sense. 18.6 MeV beta energy seemed a bit low to me. Although, it does say here that low energy beta radiation is needed to prevent harmful radiation:
"Atomic batteries use radioisotopes that produce low energy beta particles or sometimes of varying energies alpha particles. Low energy beta particles are need ed to prevent the production of high energy penetrating Bremsstrahlung radiation that would require heavy shielding. Radioisotopes such as Tritium, Nickel-63 and Promethium-147 have been tested. Plutonium-238 may have also been tested."
-Wikipedia
although i guess you could solve the bremsstrahlung problem with thcker shielding, and therefore you wouldnt have the mix of charges within the battery
-
They already make "nuclear batteries". There are a great number of people walking around this Earth right now who have some plutonium imbedded in their chest. For these people, their pacemakers are powered by small plutonium batteries which should last their entire lifetime.
Yes, but they are of the RTG variety, as plutonium generates an unusual amount of heat when it decays. They really havnt made a practical/working model of the beta-powered battery. They have made ones with a phospherenscent material and an alpha emitter, and plenty of RTGs, but the beta ones are still in R&D
-
United Nuclear has some Thallium-204 that puts only Beta radiation something to 763MeV. Is this enough punch? Think the presence of alpha or gamma would matter? If not, maybe get something that emits all three with Beta being the most powerful. Problem with this stuff is that its going to be freaking expensive. 60 bucks for one uCi.
Also noticed some Polonium-210 that is alpha only. $60 for .1uCi (almost nothing) where the alpha particles are 5304KeV. How does that compare to americium? Jdurg: do you have a good resouce where I can look up known amounts of radiation energy from radioactive isotopes?
Any leads of buying a curie of tritium?
-
u can get tritium from glow-in-the dark gun sights, watch dails, and other, expensive things. you can get gaseus tritium from "trasers". As for polonium, its barely worth the money. it has a half-lif of about 180 days, and 0.1 Uci is barely anything. as for thallium, that should work, as long as you have money, you dont need much of that stuff to make a battery
-
1 Curie of ANYTHING would be incredibly expensive and dangerous. Most likely, you would need an NRC license to even posses a curie of a radioisotope. The majority of radioisotopes are sold on the microcurie scale as a full curie is actually a great deal of radiation. I have two grams of depleted Uranium, and that is only about 0.6 uCi. I will be getting another ~5 gram chunk shortly, so I'll have a total of around 2.1 microcuries of Uranium and that's approximately 7 grams of the stuff. So to put that in perspective, you would need about 3,333 KILOGRAMS of depleted uranium to equal the amount of radiation in ONE GRAM of Radium-226. WOW is Radium radioactive. :o
-
You should get some for your collection!
I would love to play with radium, but "play" is a bad word for it because I don't want to die. I think I'm just going to order some stuff off unitednuclear until I get rich enough to buy my own lab and get radium... then have someone mess with it for me. Or the smoke detector approach could work too. How would I go about getting one of those licenses anyway? Is there an online application I can find? The only apps for fun stuff I found is through the ATF for getting a license to produce high explosives.
-
The battery project has been put on hold :-[
Lack of money. The army trip to Cali murdered my bank account... again. Maybe next month...
-
Mitch, any idea how Berkeley went about getting a NRC license for nuclear material? I ask you because I know you work with the stuff. I just sent off an email to the NRC regional office asking about licensing, or if even need one, if I want over 5 curies of Americium-241... I'd much rather use radium though.
-
All of the patented nuclear batteries that I have explored generate only small amounts of power. I have developed a method that generates useful amounts of electrical power using only natural obtained radioisotopes. I will be giving a lecture next month disclosing my methods... http://www.nuenergy.org/iw/2005/perreault2005.htm (http://www.nuenergy.org/iw/2005/perreault2005.htm) which is being presented at Inventor's Weekend... http://www.nuenergy.org/iw/2005/conference2005.htm (http://www.nuenergy.org/iw/2005/conference2005.htm)
-B.A. Perreault
-
I don't suppose you'll have the lecture available on the web? I would LOVE to hear it!
-
I'd much rather use radium though.
If you are lucky enough to find any number of radium-enriched trinkets in an antique shop, just dissolve them in some solvent (i dont know which one) with some barium sulphate. if you filter the solution, the barium sulphate and anything that isnt radium will stay behind, and a pure radium solution will come out.
-
I'm sure I can find plenty of radioactive junk in northern Arizona, there's a lot of mysterious things up there. But do I REALLY want to try and make radium salts? I mean, of course I do, but how safe is it to do? And where in the world would I get barium sulfate? After picking through nuenergy_scientists website, I saw his method for getting pure radium as opposed to the curie method, but those two methods are definantly beyond my scope of doing things.
-
Barium sulphate is easy to get. It can be used as a pigment in fireworks, and you can get it here: http://www.sciencelab.com/page/S/PVAR/10409/SLB3148 (http://www.sciencelab.com/page/S/PVAR/10409/SLB3148)
-
wow... from the looks of that website.. you can pretty much get any compound imaginable.. man ill be looking into this..