The Iranians claim to have produced enriched uranium “to the 3.5% level”. That is pure enough to use as nuclear fuel, though nowhere near what would be needed to make a bomb. Experts say the bank of 164 centrifuges that the Iranians used is not enough to churn out significant amounts.
The centrifuges are needed because natural uranium is useless to feed nuclear reactors or to make bombs. First the ore must be processed to extract the metal – and 25,000 tonnes of ore yields 50 tonnes of metal. Less than 1% of that is uranium 235, which can be forcibly split to release energy. The rest is uranium 238, its less volatile radioactive cousin.