Uranium
| Uranium | |
|---|---|
| Properties | |
| Atomic symbol | U |
| Atomic number | 92 |
| Classification | Metallic |
| Atomic mass | 238.02891 amu |
| Other Information | |
| Date of discovery | 1789 |
| Name of discoverer | Martin J. Klaproth |
| Name origin | From the planet Uranus. |
| Uses | For many centuries it was used as a pigment for glass. Now it is used as a fuel in nuclear reactors and in nuclear weapons. Depleted uranium is used in the kinetic penetrators of armor-piercing artillery shells, armor plating on tanks, and as ballast in the wings of some large aircraft. |
| Obtained from | Primary uranium bearing ores are uraninite, autunite, carnotite, samarskite and torbernite. |
Uranium (U) is a heavy, naturally radioactive, metallic element with an atomic number of 92.
Isotopes
Its two principally occurring isotopes are uranium-235 and uranium-238. Their respective proportions play a large role in its use.
Uranium-238 is the dominant isotope, making up 99.3% (mass basis) of natural uranium. This percentage varies little between mines. In nuclear reactors, it plays an important role by absorbing neutrons to produce a radioactive isotope which subsequently decays to the isotope plutonium-239, which is fissionable by the thermal neutrons present in conventional light water reactors.
Uranium-235 is indispensable to the nuclear industry because it is the only isotope existing in nature that is fissionable by the thermal neutrons. It makes up 0.7% of natural uranium. In a process called enrichment, the proportion of uranium-235 is increased by small amounts in hundreds of steps to produce fuel of 2% to 5% uranium-235. This, unlike natural uranium, can sustain a nuclear chain reaction in a light water reactor.
Applications
Depleted uranium is a by-product of enriched uranium, a mixture of the 235 and 238 isotopes with a lower concentration of uranium-235 than in nature. It is one of the densest materials known to man. As such, it has been used for artillery shells, tank armor, ballast, and gyroscopes. There are no known serious health risks stemming from external exposure to it,[1][2] however it can still cause heavy metal poisoning when ingested, in the same manner as commonplace elements such as lead, mercury, and cadmium.
Uranium compounds display a wide range of colors and have been used for coloring ceramic glazes and glass.