To recreate "little boy", you would need about 10 tons of natural uranium. Absent any better ores, you could mine that from coal ash, which typically has a ura

To recreate "little boy", you would need about 10 tons of natural uranium. Absent any better ores, you could mine that from coal ash, which typically has a uranium concentration of 10-100ppm. You really think that's limiting? It's not... for a weapons program, that kind of ridiculously expensive process would be worth it. For comparison, to fuel one reactor of 1GW(e) for a year, you need about 200 tons of uranium. Even that could be taken from coal ash, but part of the appeal of nuclear power is that you don't want to produce coal ash anymore...