User:Damankh/sandbox

Summary: I'm going to be editing two sections of the Wiki page about nuclear chain reactions. The first will be what kind of fuel is used, as there's very little information on that and they only specify "low-enriched oxide material (e.g. UO2)". The second will be a new section detailing the process of how to enrich these elements and prepare for fission.

Original Article: Nuclear chain reaction

Edits:

Fuel section

Nuclear weapons employ high quality, highly enriched fuel exceeding the critical size and geometry (critical mass) necessary in order to obtain an explosive chain reaction. The fuel for energy purposes, such as in a nuclear fission reactor, is very different, usually consisting of a low-enriched oxide material (e.g. UO2). '''There are two primary isotopes used for fission reactions inside of nuclear reactors. The first and most common is U-235 or uranium-235. This is the fissile isotope of uranium and it makes up approximately 0.7% of all naturally occurring uranium. Because of the small amount of uranium-235 that exists, it is considered a non-renewable energy source despite being found in rock formations around the world. U-235 cannot be used as fuel in its base form for energy production. It must undergo a process known as enrichment to produce the compound UO2 or uranium dioxide. The uranium dioxide is then pressed and formed into ceramic pellets which can subsequently be placed into fuel rods. This is when the compound uranium dioxide can be used for nuclear power production. The second most common isotope used in nuclear fission is Pu-239 or plutonium-239. This is due to its ability to become fissile with slow neutron interaction. This isotope is formed inside nuclear reactors through exposing U-238 to the neutrons released by the radioactive U-235 isotope. This neutron capture causes beta particle decay that enables U-238 to transform into Pu-239. Plutonium was once found naturally in the earth’s crust but only trace amounts remain. The only way it is accessible in large quantities for energy production is through the neutron capture method.'''

Enrichment Process

'''The fissile isotope uranium-235 in its natural state is unfit for nuclear reactors. In order to be prepared for use as fuel in energy production, it must be enriched. The enrichment process does not apply to plutonium. Reactor-grade plutonium is created as a byproduct of neutron interaction between two different isotopes of uranium. The first step to enriching uranium begins by converting uranium oxide (created through the uranium milling process) into a gaseous form. This gas is known as uranium hexafluoride which is created by combining hydrogen fluoride, fluorine gas, and uranium oxide. Uranium dioxide is also present in this process and it is sent off to be used in reactors not requiring enriched fuel. The remaining uranium hexafluoride compound is drained into strong metal cylinders where it solidifies. The next step is separating the uranium hexafluoride from the depleted U-235 left over. This is typically done with centrifuges that spin fast enough to allow for the 1% mass difference in uranium isotopes to separate themselves. A laser is then used to enrich the hexafluoride compound. The final step involves reconverting the now enriched compound back into uranium oxide, leaving the final product: enriched uranium oxide. This form of UO2 can now be used in fission reactors inside power plants to produce energy.'''

Sources:

https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/introduction/nuclear-fuel-cycle-overview.aspx

https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/plutonium.aspx#ECSArticleLink0

https://energyeducation.ca/encyclopedia/Uranium_hexafluoride

https://energyeducation.ca/encyclopedia/Nuclear_fuel

https://www.eia.gov/energyexplained/nuclear/