Asteroid Mining?

[Rev. Rye]

I'm also wondering if Googling a bunch of stuff about plutonium puts you on an FBI watch list.

I get the feeling that, if that were true, that'd probably include some random kids in a middle or high school chem class.

Also, I take it you're asking for this for a Sci-Fi book you're writing. Because in reality, plutonium is stupefyingly rare in nature, with the only natural sources being trace amounts that came from the decay of Uranium-239, which mostly come from the aftermath of nuclear tests and accidents, and that's so small it's measured in parts per trillion. I'd be legitimately shocked if the amount of natural Plutonium on Earth would add up to more than a gram. In the real world, it'd be far easier to manufacture it than mine it, since the global stockpile of manufactured plutonium is about 540 tons.

Fortunately, sci-fi doesn't necessarily have to be beholden to such inconvenient facts. Especially if you're dealing with civilizations living in the asteroid belt, like you mentioned in the OP.