with the number of nuclear weapons in the world now, and how old a lot are, how is it possible we’ve never accidentally set one off?

Question

Title says it. Really curious how we’ve escaped this kind of occurrence anywhere in the world, for the last ~70 years.

In: Engineering

Answer 1

Nuclear bombs are incredibly difficult to set off. The principle is easy: take a bunch of fissionable material and squeeze it really hard. Actually getting this done in practice though is quite an engineering problem. Modern devices use a shell of shaped conventional explosives that all have to be set off at exactly the same time. The only way this is possible is with precise timing mechanisms. And electrical surge or unexpected event isn’t going to trigger the explosives with the necessary precision to set off the fission reaction. It would just be a conventional explosion that scatters the fission material around the blast area.