Civilian and military uranium
The natural uranium that is extracted from mines is very poor in the fissile nuclei of uranium 235. It has to be enriched 5- or 6- fold (going from a 0.7% uranium 235 content to 3-4% of uranium 235) in order to be an effective fuel for commercial reactors; an enrichment which can be achieved by gaseous diffusion or centrifuging techniques. If the percentage content is upped to around 90%, then the resulting uranium is rich enough to be used in the manufacture of atomic bombs. Mastering these enriching techniques is a vital step in the acquiring of nuclear capability.