I think bombs went off on 2077 originally, but then 200 years later happened second war or smth and bombs fell again. Because Cooper is walking around as a ghoul for about 200 years or so, and Maximus said that bombs dropped when he was a child, so 10-15(?) years ago. I guess another war happened in his childhood.
*But if it was 200+ years, I don't quite understand how Moldaver is alive. Well... we saw some people were frozen in this episode, so I guess maybe she froze herself in one of those pods and that's how is she alive.