[ramesh31]

>Is this still true in the 2020s?

The laws of physics haven't changed in 80 years. Even if you started with yellow cake uranium (~70% enriched, and itself already nearly impossible for a non-state actor to acquire), to reach weapons grade at >95% you'd need hundreds of tons of it, and massive industrial scale chemical facilities to convert that into uranium hexafluoride and pull out the U235 isotopes [0], where the ratio of U235 to U238 (the non-fissile isotope) is 99:1. The vast majority of the Manhattan Project was in the engineering challenges required to do this, not really in the construction of the bomb. So far, only 5 countries in the world have been able to do it.

[0] https://web.evs.anl.gov/uranium/guide/uf6/index.cfm#:~:text=....

[djrogers]

> So far, only 5 countries in the world have been able to do it.

I think you’re a tad optimistic there - sadly we have many more than 5 nuclear powers today.

[speed_spread]

5 countries have developed Uranium enrichment facilities.

[colechristensen]

Argentina, Brazil, China, France, Germany, India, Iran, Japan, the Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States

There’s the list of “known” meaning publicly acknowledged countries with operating enrichment facilities, more than 5.

Notice it doesn’t include Israel which more or less everyone believes has nuclear weapons meaning enrichment facilities. There are several other countries which are very reasonably believed to have or have had enrichment programs.

[dredmorbius]

South Africa had at one time.

[acchow]

I was thinking more that the industrial production has increased 10x in 70 years. Private companies can now build rockets that go to space...

[samus]

Private companies could indeed do it. Heck, the mining and refining part is probably done by private entities these days. However, the only legal customers are nuclear power plants and governments.