In the news it is often mentioned that some countries are going to enrich uranium to "military grade" (i.e. 80%+) and that it is possible to use it for a nuclear bomb.
1) Is that correct that there are no nuclear warheads in service made of U-235, as plutonium ones are much smaller & much more efficient (i.e. burn most of it's fissile fuel unlike U-235 cannon-type ones)?
2) Is that correct, that the only current military uses for 80%+ U-235 are naval nuclear reactors and in rare occurrences - case and/or X-Ray "reflector" in Teller–Ulam configuration as it is slightly better neutron breeder compared to more commonly used U-238 and allows to slightly reduce mass of "high-tech" plutonium charge at the same yield?