Water injected with oxygen or an alkali, acid or other oxidizing solution is circulated through the uranium ore, extracting the uranium. The uranium solution is then pumped to the surface. The vast majority of nuclear power reactors use the isotope uranium as fuel; however, it only makes up 0.
This increases the uranium concentration from 0. A small number of reactors, most notably the CANDU reactors from Canada, are fuelled with natural uranium, which does not have to be enriched.
The enrichment process requires the uranium to be in a gaseous form. This is achieved through a process called conversion, where uranium oxide is converted to a different compound uranium hexafluoride which is a gas at relatively low temperatures. For comparison, a MWe coal-fired power plant burns about 10 tons about 10 million kg of coal per day.
Since a typical fuel cycle takes about days month fuel cycle , the annual fuel consumption is about:. Typically, when uranium nucleus undergoes fission, the nucleus splits into two smaller nuclei triple fission can also rarely occur , along with a few neutrons the average is 2. The average of the fragment atomic mass is about , but very few fragments near that average are found.
It is much more probable to break up into unequal fragments , and the most probable fragment masses are around mass 95 Krypton and Barium. Most fission fragments are highly unstable radioactive nuclei and undergo further radioactive decays to stabilize themselves. In general, nuclear fission results in the release of enormous quantities of energy.
The amount of energy depends strongly on the nucleus to be fissioned and also depends strongly on the kinetic energy of an incident neutron. It is necessary to identify the individual components of this energy precisely to calculate the power of a reactor. At first, it is important to distinguish between the total energy released and the energy that can be recovered in a reactor.
The total energy released in fission can be calculated from binding energies of the initial target nucleus to be fissioned and binding energies of fission products. But not all the total energy can be recovered in a reactor. For example, about 10 MeV is released in the form of neutrinos in fact, antineutrinos. Since the neutrinos are weakly interacting with an extremely low cross-section of any interaction , they do not contribute to the energy that can be recovered in a reactor.
See also: Energy Release from Fission. All commercial light water reactors contain both fissile and fertile materials. In fact, during fuel burnup, the fertile materials conversion of U to fissile Pu known as fuel breeding partially replace fissile U, thus in a nuclear reactor, more fissile isotopes are involved in power generation. Since the Pu fission releases a very similar amount of energy, this example can be generalized to:.
The fuel breeding permits power reactors to operate longer before the amount of fissile material decreases to the point where reactor criticality is no longer manageable. The fuel breeding in the fuel cycle of all commercial light water reactors plays a significant role.
As burnup increases, a higher percentage of the total power produced in a reactor is due to the fuel bred inside the reactor. Uranium has the highest atomic weight 19 kg m of all naturally occurring elements.
Uranium occurs naturally in low concentrations in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. Uranium ore can be mined from open pits or underground excavations. The ore can then be crushed and treated at a mill to separate the valuable uranium from the ore.
Uranium may also be dissolved directly from the ore deposits in the ground in-situ leaching and pumped to the surface. Uranium mined from the earth is stored, handled, and sold as uranium oxide concentrate U 3 O 8. Also in Gasoline explained Gasoline Octane in depth Where our gasoline comes from Use of gasoline Prices and outlook Factors affecting gasoline prices Regional price differences Price fluctuations History of gasoline Gasoline and the environment.
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