Comments by "jeppen" (@jesan733) on "Does Iran Actually Have a Nuclear Weapon? || Peter Zeihan" video.

@antman7673 problem is that if you can enrich to reactor grade, you can enrich to weapons grade. The energy requirements is mainly in the beginning when enrichment is very low. Going higher is cheap and quick in comparison.
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@antman7673 yes, it's both this multiplying effect and the kindof "pyramid" reduction in feed amount when enriching a fixed amount of feed. So if we start with 1 ton of natural U and get it up to reactor grade by enriching it 5x, then the feed to the next "multiplication" step is just ~200 kg, so you can get that feed from 4% to 20% for 1/5 of the energy cost of the first step, and then the last step to almost 100% is 1/25 of the first step. Thus when someone wants "breakout capacity", e.g. the ability to quickly create weapons grade uranium, enriching the reactor grade base feed is around 2/3 of the total work.
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