If the fissile core is anything like the original Trinity test one, it relies on a solid ball of plutonium metal being compacted to reach criticality (modern on

If the fissile core is anything like the original Trinity test one, it relies on a solid ball of plutonium metal being compacted to reach criticality (modern ones may be hollow). This means the explosion wavefront needs to arrive simultaneously all around the ball. This is hard! A ton of the computational effort legendarily described by Feynman with his IBM tabulator/multiple coloured cards story was, I believe, just to make this work. Link to the relevant part (the whole lecture is a hoot). https://youtu.be/uY-u1qyRM5w?t=2800 https://youtu.be/uY-u1qyRM5w?t=2800 Anyway the original bomb had a lot of detonators all around that needed to be fired right. Modern ones have only two, from the little I've seen in published imagery. https://en.wikipedia.org/wiki/Pit_%28nuclear_weapon%29#Safety_considerations https://en.wikipedia.org/wiki/Pit_%28nuclear_weapon%29#Safet... One hopes this is arranged so simultaneous firing of both detonators results in a fizzle, and a precise stagger is needed. Either way though, an external explosive force will just disassemble the thing, not cause it to go off.