uranium$88869$ - tradução para alemão
![Schematic diagram of uranium isotope separation in a [[calutron]] shows how a strong magnetic field is used to redirect a stream of uranium ions to a target, resulting in a higher concentration of uranium-235 (represented here in dark blue) in the inner fringes of the stream.](https://commons.wikimedia.org/wiki/Special:FilePath/Electromagnetic separation.svg?width=200 "Schematic diagram of uranium isotope separation in a [[calutron]] shows how a strong magnetic field is used to redirect a stream of uranium ions to a target, resulting in a higher concentration of uranium-235 (represented here in dark blue) in the inner fringes of the stream.")
 (cropped).jpg?width=200 "Gaseous diffusion uses semi-permeable membranes to separate enriched uranium")
![billet]] of highly enriched uranium metal](https://commons.wikimedia.org/wiki/Special:FilePath/HEUraniumC.jpg?width=200 "billet]] of highly enriched uranium metal")
![A drum of [[yellowcake]] (a mixture of uranium precipitates)](https://commons.wikimedia.org/wiki/Special:FilePath/LEUPowder.jpg?width=200 "A drum of [[yellowcake]] (a mixture of uranium precipitates)")
![[[Boiling water reactor]] (BWR)](https://commons.wikimedia.org/wiki/Special:FilePath/Boiling water reactor english.svg?width=200 "[[Boiling water reactor]] (BWR)")
![largest operational nuclear power facility in the world]].](https://commons.wikimedia.org/wiki/Special:FilePath/Bruce-Nuclear-Szmurlo.jpg?width=200 "largest operational nuclear power facility in the world]].")
![Unit 1 of the [[Cernavodă Nuclear Power Plant]] in Romania](https://commons.wikimedia.org/wiki/Special:FilePath/Centrala Atomica Cernavoda 01.jpg?width=200 "Unit 1 of the [[Cernavodă Nuclear Power Plant]] in Romania")
![[[Olkiluoto Nuclear Power Plant]] in [[Eurajoki]], Finland. The site houses of one of the most powerful reactors known as EPR.](https://commons.wikimedia.org/wiki/Special:FilePath/Olkiluoto Nuclear Power Plant 2015-07-21 001.jpg?width=200 "[[Olkiluoto Nuclear Power Plant]] in [[Eurajoki]], Finland. The site houses of one of the most powerful reactors known as EPR.")
![[[Pressurized water reactor]] (PWR)](https://commons.wikimedia.org/wiki/Special:FilePath/PressurizedWaterReactor.gif?width=200 "[[Pressurized water reactor]] (PWR)")
![The Ukrainian city of [[Pripyat]] abandoned due to a nuclear accident, which took place at [[Chernobyl Nuclear Power Plant]] on 26 April 1986, seen in the background.](https://commons.wikimedia.org/wiki/Special:FilePath/View of Chernobyl taken from Pripyat.JPG?width=200 "The Ukrainian city of [[Pripyat]] abandoned due to a nuclear accident, which took place at [[Chernobyl Nuclear Power Plant]] on 26 April 1986, seen in the background.")
Definição
Wikipédia
Uranium (92U) is a naturally occurring radioactive element that has no stable isotope. It has two primordial isotopes, uranium-238 and uranium-235, that have long half-lives and are found in appreciable quantity in the Earth's crust. The decay product uranium-234 is also found. Other isotopes such as uranium-233 have been produced in breeder reactors. In addition to isotopes found in nature or nuclear reactors, many isotopes with far shorter half-lives have been produced, ranging from 214U to 242U (with the exception of 220U). The standard atomic weight of natural uranium is 238.02891(3).
Naturally occurring uranium is composed of three major isotopes, uranium-238 (99.2739–99.2752% natural abundance), uranium-235 (0.7198–0.7202%), and uranium-234 (0.0050–0.0059%). All three isotopes are radioactive (i.e., they are radioisotopes), and the most abundant and stable is uranium-238, with a half-life of 4.4683×109 years (close to the age of the Earth).
Uranium-238 is an alpha emitter, decaying through the 18-member uranium series into lead-206. The decay series of uranium-235 (historically called actino-uranium) has 15 members and ends in lead-207. The constant rates of decay in these series makes comparison of the ratios of parent-to-daughter elements useful in radiometric dating. Uranium-233 is made from thorium-232 by neutron bombardment.
Uranium-235 is important for both nuclear reactors (energy production) and nuclear weapons because it is the only isotope existing in nature to any appreciable extent that is fissile in response to thermal neutrons, i.e., thermal neutron capture has a high probability of inducing fission. A chain reaction can be sustained with a sufficiently large (critical) mass of uranium-235. Uranium-238 is also important because it is fertile: it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope plutonium-239, which also is fissile.
