Uranium

**Definition:** A radioactive element of the actinide series of metals. It has an atomic symbol U, atomic number 92, and atomic weight 238.03. U-235 is used as the fissionable fuel in nuclear weapons and as fuel in nuclear power reactors.

**Tree numbers:** - D01.268.271.100.950 - D01.268.556.900 - D01.496.749.305.100.950 - D01.552.020.940 - D01.552.544.900