>>41396706
>if the tech is relatively simple
Well yeah that's the other unspoken thing about nukes. It's stupidly low tier technology.
Hypothetically a bronze age civilization that's stacking up raw ore in an enclosed room can discover uranium's properties since raw uranium ore will emit heat if you pile enough up. This would be noticeable to a person without detection equipment or thermometers.

There are even natural nuclear reactors that have formed inside the Earth's crust in the past just from uranium ore being compressed to the point of subcriticality. Fission is in fact stupidly easy, and once you know what uranium is there is only a matter of time before you can achieve a runaway reaction.
You also don't need optics, electronics, lathes or any kind of industrial-era manufacturing tech to make nuclear devices. Just explosives and physics knowledge.

There is a reason Oppenheimer quoted Bhagavat gita. Anyone who truly understands nuclear tech knows it's going to be the first important thing a civilization with any kind of ambition achieves.