Originally posted by Daarkseid
I believe you're only talking about the facilities that enriched the Uranium used in those bombs. He may have been talking about the uranium itself before it was processed.
Enriched Uranium is essentially an amount of Uranium that is made up entirely of the Uranium isotope that is unstable(I forget the number for this isotope, I think its U-235). Only very insignifigant amounts of this isotope can be found in actual uranium, and thus actual uranium, as it is found in nature, is too stable for a chain reaction.
I really don't know much more than that, I'm afraid. I know that one byproduct of this enriching process is the depleted uranium that is used for tank shielding and ammunition in the cannons mounted on fighter planes.
Yes, you are pretty much correct. There are two main isotopes of Uranium; U-238 and U-235. (Many other istopes exist, but those are the two most prevalant). Uranium-238 is by far the most common, and most stable isotope of Uranium. U-238 is a poor fission material since it will not absorb neutrons, nor will it produce neutrons upon decay. U-235, however, will produce many neutrons upon decay and it will also absorb neutrons, thus leading to fission. Therefore, when the U.S., or any nation for that matter, wants to build a Uranium bomb, they need the fissionable material to be U-235 so that they can get a chain reaction going.
In order to separate the two isotopes, they need to "encrich" the Uranium which is extracted from the pitchblende/uraninite ores. This is done by reacting the uranium metal with fluoride gas. This will produce the incredibly corrosive, and toxic, uranium hexafluoride (UF6) gas. Due to the difference in mass betwen the two Urainum isotopes, the UF6 w/ U-235 will pass through a gas diffusion apparatus quicker than UF6 w/ U-238 will. If the gas is run through the appartus enough times, a pure form of UF6 w/ U-235 will result. This gas is then converted back into Uranium metal and Fluoride gas, and you have pure (relatively speaking) Uranium 235. (As well as some U-238 and various other isotopes). The U-235 is then used as the nuclear "fuel" while the U-238 is used as a neutron shield which will deflect stray neutrons back into the fission core, thus assuring a nuclear chain reaction.
So in WWII, the Oak Ridge facilities in Tennessee were vital in the enrichment of the unpure Uranium. The Uranium metal most likely did come from Canada, although I'm fairly certain that a good majority came from the pacific northwest. (I believe that the vast majority of uranium deposits in the world are in volcanically active areas, or places that have a history of prior volcanic activity. This is due to the fact that the Uranium near the surface came from within the Earth's core. So Uranium deposits would be most likely in areas with high geological activity). Relatively speaking, Uranium-238 is pretty low-level in terms of radioactivity and is also fairly non-toxic. Uranium-235 is VERY radioactive, and it's toxicity is due to that radioactivity.
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