Eli5: Why is it so hard for a country to make a nuclear bomb?

Question

I’m assuming the science of making one is out there. Why then countries like Iran who so want to develop atomic weapons haven’t been able to do so?

In: Physics

Answer 1

Making a nuclear bomb is pretty trivial. In an Nth Country Experiment three young PhDs who had zero experience in weapon development figured out how to create a nuke using only *publicly available information*. In *1964*.

Developing delivery systems, though? Now that’s a different question. ICBMs are very complicated and very expensive.