ATMosby writes "The BBC has an article that pretty much sums up everything you might need to know if you wanted to refine nuclear fuel and build some atomic weapons." From the article: "Uranium is the basic raw material of both civilian and military nuclear programmes. It is extracted from either open-cast pits or by underground mining. Although uranium occurs naturally all over the world, only a small fraction is found in concentrated ores. When certain atoms of uranium are split in a chain reaction, energy is released. This process is called nuclear fission."