Possible Clues:

• Element in uniform, skull cap removed
• One of the actinide series
• Radioactive element of atomic number 92
• Controversial energy source
• Mineral used in nuclear reactors
• Chemical element, source of nuclear energy
• Although never non-U, always radiant
• U in an elementary manner
• It's elementary that this could never be non-U
• Constituent of pitchblende