Alex WellersteinVerified account

Known nuclear tests by regional nuclear powers: India: 6 Pakistan: 6 North Korea: 6 Israel: 0 or 1 South Africa: 0 DPRK can probably stop where it is and still be fine.

I wouldn't say fine. I'd say adequate. Both India and Pakistan want to test more. They want more advanced designs. North Korea nuclear engineers probably would, too. We did over 1,000. Stopping tests stops advancement of designs, reduces confidence for those with a only a few.

This boils down to “what does it take to deter?” For my money, 200kT is enough. North Korea had a sequence too, whereas India and Pakistan did not. They are probably in a better position than either of those two.

I had a long talk some years ago with someone connected to the US nuke testing world. He told me that he and his colleagues had concluded that you could get reasonably high confidence with very few tests if you had OK computer models and knew what you were looking for.

He even thought you could get away with reasonably OK confidence without testing at all. He noted that in the global history of nuclear testing the number of actual fizzles is very small and mostly reserved for high-risk/unusual designs (e.g. LLNL's hydride bombs).