No, it's impractical to use civilian reactors for generating materials for a nuclear bomb (I don't count "dirty" bombs as nuclear). Also usually spent fuel rods are returned to the country of production.

Certain kinds of civilian reactors produce plutonium with large amounts of higher isotopes, but (1) it's still possible to use that stuff in bombs, with boosting, and (2) other reactor type produce plutonium that's better than weapons grade (for example, fast breeders with a breeding blanket region around the core; the Pu from that blanket is almost entirely 239Pu, and remember that scaling nuclear to supply world energy demand will likely require breeding.)