|MadSci Network: Physics|
First I'd like to mention that radon comes from radium and not directly off uranium. Often there are signifcant natural concentrations of just radium ores. These radium ore bodies have been mined in the past for industrial and medical purposes without significant concentrations of uranium in them. So even though there is radon, it does not necessarily mean there are signifcant concentrations of uranium available. Now back to your question of building an atomic weapon. One of the first problems "someone" might encounter trying to remove uranium from bedrock is the LOW natural concentration of uranium in soils. It takes TONS, I mean tons, of naturally bearing ores to even produce a significant amount of uranium. This may mean tearing up one's entire neighborhood, if not town, to access enough of the ore to obtain uranium. However, if one could get this access, there would still be additional obstacles to overcome. The process seems so simple and lesser technology could be used; but just the cost and time needed alone would be massive. Many of the chemicals and processes used are quite hazardous, if not governmentally regulated. For someone to attempt to build a "nuclear" bomb would undertake quite elaborate processes and equipment just to get the first few steps accomplished. The next additional steps normally take sophisticated laboratories to make sure no additional contaminants enter into the process and make the product useless, much less protect the workers from the chemical dangers. Even though the uranium is giving off minor amounts of radiation, the biggest dangers are the toxic effects of the chemical nature of uranium and the other chemicals used in the uranium recovery process. More accidents and injuries have happened because of "chemcial" explosions than anything radioactive. If one would be able to control the chemical dangers during the processing and keep the product pure enough, quite a bit of uranium would still be needed and would need to be greatly enriched to be effective in a weapon. So now even more time and money is spend to accomplish this as well as dealing with the LARGE amount of waste products generated. Once this is done, if it could be done at all in a garage, the construction of the mechanical parts of the bomb would need to be devised. Just because uranium or plutonium may be in something does not by any means make it a nuclear weapon. Certain reactions must be gauranteed to occur in a specific order and interact with other parts of the device to become a bomb. The nuclear reaction part (not just the natural radiation emitted from the uranium or plutonium but the actual fission process) must interact in a specific manner with the rest of the mechanical parts to become an atomic weapon. This is by no means easy and something I would not try in a garage let alone a scientific lab. So in fewer words, it would be greatly unlikely someone could make an atomic bomb in their garage as television and movies would have you believe. They leave out all the other non-glamourous but important information like the other health and safety hazards that go along with process, the amount of materials needed and wastes produced, much less the GREAT COST to make an atomic weapon. It's so easy to say "OOO, look I found a piece of uranium. Let's make a bomb," and get a great movie out of it. Unfortunately reality doesn't quite work that way. Reality is a lot of hard work and expense and this is no exception. In my option, it's a lot easier to build a bicycle in your garage (even though the instructions with most bicycles now days leads you to believe building a bomb would be easier) than an atomic weapon.
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