Nuclear reactions show the irradiation of uranium-235 at the Savannah River Site. This produced the intermediate neptunium-237, which was then transformed into plutonium-238. Pu-238 fueled the first ...

It either must be enriched—made more concentrated in a rare form of uranium (U-235)—or converted into plutonium (Pu-239). Heavy water can play a role in breeding weapons-grade plutonium from ...