Search results
Results from the WOW.Com Content Network
Since the exact rate at which uranium decays into lead is known, the current ratio of lead to uranium in a sample of the mineral can be used to reliably determine its age. The method relies on two separate decay chains , the uranium series from 238 U to 206 Pb, with a half-life of 4.47 billion years and the actinium series from 235 U to 207 Pb ...
Th/U ratio Thorium content divided by uranium content. Most of the detrital zircon grain origins can be identified through Th/U ratio, where Th/U < 0.01 implies possible metamorphic origin and Th/U > 0.5 implies igneous origin. Intermediate origin lies between 0.01 and 0.5. 207 Pb/ 235 U Isotope ratios measured by instrument for further age ...
The uranium to zirconium for different parts of the solid differs a lot, in the brown lava a uranium rich phase with a U:Zr ratio of 19:3 to about 38:10 is found. The uranium poor phase in the brown lava has a U:Zr ratio of about 1:10. [24] It is possible from the examination of the Zr/U phases to know the thermal history of the mixture.
The uranium to zirconium ratio in different parts of the solid differs a lot, in the brown lava a uranium-rich phase with a U:Zr ratio of 19:3 to about 19:5 is found. The uranium-poor phase in the brown lava has a U:Zr ratio of about 1:10. [37] It is possible from the examination of the Zr/U phases to determine the thermal history of the mixture.
The three long-lived nuclides are uranium-238 (half-life 4.5 billion years), uranium-235 (half-life 700 million years) and thorium-232 (half-life 14 billion years). The fourth chain has no such long-lasting bottleneck nuclide near the top, so almost all of the nuclides in that chain have long since decayed down to just before the end: bismuth-209.
Uranium alloys that have been used include uranium aluminum, uranium zirconium, uranium silicon, uranium molybdenum, uranium zirconium hydride (UZrH), and uranium zirconium carbonitride. [3] Any of the aforementioned fuels can be made with plutonium and other actinides as part of a closed nuclear fuel cycle.
Uranium is a chemical element with the 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.
Yttrium-90 is produced by the nuclear decay of strontium-90 which has a half-life of nearly 29 years and is a fission product of uranium used in nuclear reactors. As the strontium-90 decays, chemical high-purity separation is used to isolate the yttrium-90 before precipitation.