[tialaramex]

Nuclear bombs are strongly disinclined to "go boom" unlike say TNT. Turning the energy from splitting atoms into a large explosion, which is what you want from a weapon, will require precise timing. If you get it wrong either nothing happens, or you maybe create a small detonation, and cover a modestly sized area with dangerous debris from the failed attempt. Just throw a box of grenades into a waste water treatment plant or something instead for a fraction of the cost.

[mywittyname]

For reference, there have been a number (dozens, at least) of nuclear devices dropped accidentally all over the world (some of which landed in the USA), but none have ever accidentally detonated.

This was a plot device in the popular Fallout games. Where a city had built up around a nuclear bomb which failed to detonate during a nuclear war.

[kadoban]

Isn't getting the timing right just "zap all the bits at the same time" ?

Are these still basically a soccer ball of explosives encircling a core of subcritical nuclear material that "just" needs to be compressed?

I think all of my knowledge of nukes might be based on https://en.m.wikipedia.org/wiki/The_Manhattan_Project_(film) xD