I like this idea, but... "Hey pre-industrial civilization, did you know that if you pack enough purified uranium together in a small space, it will chain

I like this idea, but... "Hey pre-industrial civilization, did you know that if you pack enough purified uranium together in a small space, it will chain react and you'll get a big explosion? I mean REALLY big, huge actually. Don't do that." and the cycle begins a-new.