What little I know is half-remembered bits from Richard Rhodes' books about the atomic and nuclear bomb development. https://en.wikipedia.org/wiki/Richard_Rhode

What little I know is half-remembered bits from Richard Rhodes' books about the atomic and nuclear bomb development. https://en.wikipedia.org/wiki/Richard_Rhodes https://en.wikipedia.org/wiki/Richard_Rhodes Plus some lay reading. One of bits was that, before the US agreed to a test ban, American scientists ensured that it was possible to be confident that new warheads could be built, with a high confidence that they would work, even without additional testing. The people involved with this had experience drawn from the >1,000 nuclear detonations that had occurred and from designing multiple generations of warheads. There haven't been tests since 1992. "Stockpile Stewardship" - https://en.wikipedia.org/wiki/Stockpile_stewardship https://en.wikipedia.org/wiki/Stockpile_stewardship - is how we ensure the reliability of the "Enduring Stockpile" - https://en.wikipedia.org/wiki/Enduring_Stockpile https://en.wikipedia.org/wiki/Enduring_Stockpile . New nuclear weapons, that is, the "physics package", aren't developed. See https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html where the post-ban proposals say "Modifications of B-83 and B-61 bombs considered" and "Similar or the same as for the W-88". New ways of delivering them are developed. You don't need as big a boom if you can deliver the bomb to within a meter of the target, vs. the 100m of the Minuteman III, or develop methods like "Super-Fuze" which can "[boost] the overall killing power of existing US ballistic missile forces by a factor of roughly three", without changing the physics package. (Quote from https://thebulletin.org/2017/03/how-us-nuclear-force-modernization-is-undermining-strategic-stability-the-burst-height-compensating-super-fuze/ https://thebulletin.org/2017/03/how-us-nuclear-force-moderni... and see also https://nationalinterest.org/blog/the-buzz/the-super-fuze-the-big-upgrade-americas-nuclear-arsenal-22765 https://nationalinterest.org/blog/the-buzz/the-super-fuze-th... .)