Uranium dug out of the ground still can't start a reaction in a reactor. It has to pass through midstream plants that "convert" it and then "enrich" it before it becomes fuel — and that's exactly where the West is most fragile, because Russia alone controls nearly half the world's enrichment capacity. However many tons of ore the U.S. and Europe have, if no one can turn it into fuel, it's like having crude oil but no refinery. This lesson is the story of a strategic bottleneck that has become the hottest flashpoint in nuclear energy security.