They don't have them. Nobody can have something that doesn't exist.
I've seen this shit cropping up in flat Earth circles, people saying that nuclear weapons don't exist. If I build a reactor myself, what is that? lol.
Fist of all, it's a big if. Second, weapons and reactors are not the same, but yes, closely related. Flat earth is just smear by association. There is a decent book on the subject you can evaluate with an open mind. Unless, of course, you're a nigger who can't read.