Nuclear Fission BY Megan rankin and andrew mine

What is Nuclear Fission?

Nuclear fission is defined as a reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into 2 or more parts, releasing additional neutrons and energy in the form of heat (Friedland and Relyea 2015)

Nuclear fission starts with a highly unstable atom, most often an isotope of Uranium (uranium 235). A neutron is then fired at the nucleus of these atoms, making it even more unstable and causing it to split. As it does so, it emits more neutrons that will then pass through other surrounding unstable nuclei of uranium causing them to split as well and creating a chain reaction (National Science 2015)

How is Nuclear fission self-sustaining?

Self-sustaining - able to continue in a healthy state without outside assistance ( Self-sustaining 2017)

Nuclear reactions are said to be self-sustaining because they are able to occur in a controlled manner. This is done through the use of control rods. Control rods are rods of neutron absorbing material such as boron, hafnium, or cadmium that are placed in a nuclear reactor with uranium. Their job is to absorb some of the neutrons that are fission products to slow the rate of the chain reaction and ensure that it doesn't occur too quickly. Without these control rods, fission would occur at a rate that would produce an extreme amount of heat energy that would not be sustainable. (Nuclear 2017)

Isotopes and Elements that are used in nuclear energy.

Isotope- a form of an element that has the same number of protons but a different number of neutrons in the nucleus. there are over 800 radioactive isotopes (Isotope 2017)

The elements/atoms involved in nuclear power include:

  • uranium- most common fuel source; most important isotopes are uranium 235, and uranium 238; plutonium is another element that may be used as a fuel source (National Geographic 2017)
  • hydrogen & oxygen- these elements compose the cooling agent commonly used in nuclear power production, water, which is warmed by the heat created by nuclear fission. This produces steam which powers generators to produce electricity (National Geographic 2017)
  • boron, hafnium, cadmium (various elements used to make control rods)- absorb fission products to slow nuclear reactions without fissioning themselves (Grayson 2011)
Describe a half-life

A half life is the time required for half the atoms of an amount of a radioactive substance to disappear ("Half-Life", 2017). So, every time the certain half-life year passes the radioactive decay will go down by half. An example of this would be say a sample that is 500 grams has a half-life of 5 years. Then, in 5 years the sample will only have 250 grams. The next 5 years it will be 125 grams and so forth ("Radioactive Half-Life", 2017)

As Bill Nye explained in the video, it will take half of its amount of radioactive decay. These happen in isotopes of atoms, the isotopes decay by half.

How is Uranium extracted

When the uranium is mined, there are two ways of doing it. Uranium is found in rock called uranium ore. The first way it can be extracted is underground or above ground. The ore can go through one of these three processes like, blasting, drilling, or picking and shoveling. This way is called conventional open-pit or underground mining ("Fact Sheet on Uranium", 2010).

The second way is called In-Situ-Leaching. It uses a chemical process to separate the uranium from the ore. A chemical solution is injected into the drilled ore and the liquid makes the uranium fall out ("Fact Sheet on Uranium", 2010).

Explain Nuclear Fusion and why it is not a current energy source.

Nuclear Fusion is a reaction that happens when lighter nuclei are put together to make heavier nuclei. It is currently not in use as an energy source on Earth. This is because in order to create fusion energy, it requires a reactor that heats the material that is 10 times hotter than the sun. The temperature makes it very difficult to contain the materials (Friedland and Relyea, 2015).

Reference Page

Credits:

Created with images by 526663 - "coal fired power plant nuclear reactors nuclear" • mucorales - "nuclear power plant nuclear reactor nuclear" • PublicDomainPictures - "chimney concrete nuclear" • skeeze - "solar panel array nuclear plant cooling towers" • ri1987 - "air atomium atomic" • WikiImages - "uranium radioactive nuclear" • 12923 - "nuclear power plant central steam"

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