Element not in American favour? (7)
I believe the answer is:
uranium
'element' is the definition.
(I know that uranium is a type of metal)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for uranium that I've seen before include "Chemical element used to get nuclear energy" , "Mineral used in nuclear reactors" , "Radioactive element used for nuclear energy" , "Radioactive metal, atomic number 92" , "Radioactive metallic element" .)