Uranium

Uranium is a chemical element; it has symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays, usually by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which

uranium with a lower content of the fissile isotope U-235 than natural uranium

uranium in which the proportion of uranium-235 has been increased through the process of isotope separation

Uranium-238 (' or U-238') is the most common isotope of uranium found in nature, with a relative abundance above 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239. 238U cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission of one or more next-generation nuclei is probable. Doppler broadening of 238U's neutron absorption resonances, increasing abso

government research facility in Tennessee, United States

glass colored with uranium oxide

thumb|alt=A man stands in front of a C-shaped object twice his size.|An Alpha calutron tank removed from the magnet for recovery of uranium-235 thumb|alt=A large oval-shaped structure|Alpha I magnet, called the "Racetrack". The calutrons are located around the ring.

nuclides with atomic number Z = 92 and with different mass numbers

Nuclear Economy Process

radiometric dating method based on the degree to which secular equilibrium has been achieved between the parent U-234 and the daughter Th-230

naturally occurring uranium deposit where self-sustaining nuclear chain reactions have occurred

device for chemical separation

French chemist (1811–1890)

thumb|upright=1.1|Reprocessing of spent nuclear fuel by the PUREX method, first developed in the 1940s to produce plutonium for nuclear weapons, was demonstrated commercially in Belgium to partially re-fuel a LWR in the 1960s. This aqueous chemical process continues to be used commercially to separate [[reactor grade plutonium (RGPu) for reuse as MOX fuel. It remains controversial, as plutonium can be used to make nuclear weapons.]]

economically recoverable concentrations of uranium within the Earth's crust

uranium with the same isotopic ratio as found in nature

Method of separating isotopes of uranium

radiometric dating technique based on analyses of the damage trails, or tracks, left by fission fragments in certain uranium-bearing minerals and glasses

type of atom bomb

mining through artificially dissolving minerals in a borehole

technical term

uranium recovered from nuclear fuel reprocessing

Geological phenomenon

substance that is pure enough to be used to make a weapon