DJ, the key word is "yet". I do believe that they will refine some material into plutonium.
Further, I believe that even high grade uranium can be used for bombs, but they would be less powerful.
Uranium can definitely be used in nuclear weapons -- the Hiroshima bomb was a uranium bomb.
Plutonium has to be bred from uranium in a nuclear reactor, then reprocessed. I have no doubt that Iran would like to do this, but I don't think they
have the capability yet.