Stones
(g.k. goswami)
Pitchblende, the first uranium ore discovered, is the most important variety of uraninite. Other major ores include uranophane, coffinite, and carnotite. Sandstone, shale, and phosphate may contain valuable deposits of uranium ores. Granite usually has small amounts of uranium.
In the early 1990''s, the world had about 1,600,000 metric tons of uranium ore that could be mined at a reasonable cost. World production of uranium is about 32,500 metric tons a year. Canada leads all countries in the production of uranium. More than half of Canada''s uranium comes from Saskatchewan.
Uranium isotopes
In nature, uranium occurs in three isotopes (forms). Each has an atomic number (number of protons in the nucleus) of 92. Each isotope, however, has a different number of neutrons and so differs in its atomic mass number (total number of protons and neutrons in the nucleus). The lightest natural isotope has 92 protons and 142 neutrons, for a total of 234 nuclear particles. The name of this isotope, U-234, comes from the chemical symbol for uranium--U--and the atomic mass number. The other two natural isotopes of uranium are U-235 and U-238. These isotopes have 143 and 146 neutrons, respectively. U-238 makes up about 99.28 per cent of all natural uranium. U-235 accounts for approximately 0.71 per cent of all natural uranium; U-234, only about 0.006 per cent.
U-235 is the only natural isotope of uranium whose nucleus can easily be made to undergo fission--that is, to split into two. The fission process releases the nuclear energy used in power plants and weapons.Write your abstract here.
Resumos Relacionados
- Neutron Bomb
- Nuclear Showdown - North Korea Takes On The World
- The Einstein Project
- Nuclear Showdown - North Korea Takes On The World
- The Kondor File -author´s Note Part I
|
|
