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Nuclear Fission

Nuclear Fission.
by

Akber Khan

on 17 August 2010

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Transcript of Nuclear Fission

Nuclear Fission Not Quite. What is Nuclear Fission? Simply put, nuclear fission is the process of harnessing the energy of the atomic nucleus. This is done by splitting appart an atom within the containment of a nuclear reactor, which creates steam, which turns turbines, which created usable electric power. Nuclear fission, while operating on the same principles that many of us are familiar with in the form of the atomic bomb, is not quite as chaotic as its weaponized counterpart. Nuclear fission rather, harnesses the power of atomic reactions in a controlled and contained environment. It is also worth noting that it is impossible to convert a nuclear reactor to produce an atomic explosion. There are vast stores of potential energy lurking inside every atom, and nuclear fission harnesses
this energy to create electricity. How does it work? Nuclear reactions are created by splitting the atom, that much we know. But what are the processes involved in such a reaction? How would you go about splitting an atom? Would you cut it with a tiny knife? Place it in an atomic guillotine?

No. By firing subatomic particles (specificially neutrons) at the nucleus
of an atom, the atom breaks apart, releasing some of the incredible energy
in its mass. Here is a short video to help explain the process: The reactions in the core heat up water, which produces steam,
which turns the turbines, which in turn, turn a generator which as its name implies:
Generates Electricity.

Now, you may have heard of nuclear fusion, which while similar at its fundamentals is a very different process entirely. For the moment, the only place where stable fusion reactions occur are in the
hearts of massive celestial bodies like that of our Sun. In fusion, instead of atoms being ripped apart to harness their energy, they are fused together at incredibly high temperatures to create new, heavier elements. Only the most massive of stars can produce the intense conditions necessary to maintain the fusion reaction to the point of a supernovae.
Others enjoy relatively quiet deaths and settle down as white dwarfs Only massive stars have the suffecient gravity to hold the reactions in place at the core, but
when the energy being produced by the reactions becomes less than the energy required to
maintain them the result is a Supernova.

This happens at the core when Iron is being fused. The energy required to fuse iron is less than the energy it will produce, so the entire reactor fails resulting in an unparalled explosion. As briefly mentioned in the video, the blasting apart of the atom releases even more neutrons.
These too may smash into other atoms, creating a chain reaction of fission until the fuel source is spent and the reaction shuts down. In a nuclear bomb, this happens incredibly rapidly, but in a nuclear powerplant it is controlled so that energy can be effectiently harnessed. Most of the stars in the universe though, will die out
in a (relatively) quiet dim flicker and become white dwarfs A Closer look at the technical aspects. How is nuclear fission controlled? A neutron moderator helps initiate and control the nuclear reactions. While there are several substances that can be used as moderators (graphite, heavy water, beryllium), water is the most common. By slowing down fast neutrons, which can travel at up to 10% the speed of light after emerging from a subsequent nucleic split, to several kilometers per second so that the reaction may be better controlled at a slower rate. Control rods also help maintain and regulate fission reactions. They are made up of materials that can absorb large amounts of neutron without fissioning themselves. Fuel? The most valuable fuel for nuclear fission is Plutionium-239. It fits all the criteria an element must fulfill to be feasibly fissile,
and whats more is that has a half life of 24,000 years.
While this may seem like a long time, compared to the half lives of other elements
which can go into millions of years, it is considered the preferable alternative.
Half life is the amount of time it takes for the decaying substance to decrease by half. In addition to all of that, Plutonium-239 is so low in toxicity that it is only considered dangerous
if inhaled or swallowed, much safer than many other nuclear fuels and waste products. This makes it easy and safe to handle. Enriched Fuel? Enriched Uranium is Uranium which has gone through the process of isotope separation.
This process increases the composition of U-235 in Uranium fuel source. The reason for this is that U-235 is the only isotope that is naturally exisiting in nature that is also fissile, and it is extremely rare. 99% of Uranium on the planet is U-238, leaving under 1% (or around 2000 tonnes) of U-238 spread in lightly concentrated areas around the world, making it hard to acquire. Safety Concerns Nuclear powerplants are some of the most sophisticated and well built structures in the world, but that does not mean that they are immune to harm. The personnel that staff the plants are all highly trained, with many nuclear engineers and phyicists working on site. Precautions must be taken in case of certain catastrophe events. In the event of reactor instability, which can lead to a number of things including reactor melt down or a steam explosion, most powerplant's cooling systems should be able to control the temperature in the core and keep the reaction stable.
If however, a cooling system should become faulty or fail to work, the resulting meltdown would be kept contained due to the reactors containment structure. These structures are some of the strongest man has ever built, being able to withstand tremendous forces and adequately containing a reactor failure. Nuclear waste products must be disposed of correctly and carefully because due to their usually high radioactive post-fission levels, they can cause extensive damage to the human body. This may include non-fatal health problems, or fatal problems in the form of cancer and other diseases. This can lead to storage complications because the half lifes of nuclear waste are often in the tens of thousands of years, and therefore need to be contained in a safe place away from human contact or contamination where they can be left to decay. Finding appropriate room for such facilities and compounds is no easy task. Statistically speaking, nuclear power is one of the safest industries in the world. Countries Currently Using Nuclear Power Citations Thank you for listening. http://www.webresourcesdepot.com/wp-content/uploads/image/free-vector-world-map.gif http://www.cleanenergyinsight.org/wp-content/uploads/2009/08/comparingindustrysafety_graph.jpg http://hist311.wmwikis.net/file/view/nuclear-power-plant.jpg/48817115/nuclear-power-plant.jpg http://upload.wikimedia.org/wikipedia/commons/archive/7/71/20081208001759!Plutonium_pellet.jpg http://www.zastavki.com/pictures/1280x1024/2009/Creative_Wallpaper_radiation_Sign_015990_.jpg http://extranet.barneyschool.org.uk/myphysicsweb/Sankey%20Diagrams.pdf http://upload.wikimedia.org/wikipedia/commons/d/de/PWR_control_rod_assemby.jpg http://blog.autoworld.com.my/wp-content/uploads/2009/02/fuel.jpg http://anatomika.files.wordpress.com/2008/05/wall04-homero-simpsons1.jpg http://www.eskom.co.za/nuclear_energy/fuel/fuel.html http://abstract.desktopnexus.com/wallpaper/18574/ http://www.cmnh.org/site/Img/AboutUs/Pressroom/Beyond/Sun.jpg http://encyclopedia.files.wordpress.com/2006/10/nuclear_power_diagram.jpg Argentina
Armenia
Belgium
Brazil
Bulgaria
Canada
China
Czech Republic
Finland
France
Germany
Hungary
India
Iran Japan
Korea, Republic
Mexico
Netherlands
Pakistan
Romania
Russian Federation
Slovakian Republic
Slovenia
South Africa
Spain
Sweden
Switzerland
Taiwan
Ukraine
United Kingdom
USA 30 Countries
438 Powerplants Sankey Diagram While I think that nuclear energy is a wonderous source of power that could do many things for the Philippines, I do not reccommend that nuclear powerplant be established in the country. The level of sophistication and structural dependence these powerplants require is staggering. The Philippines does not have the technology, nor the waste management capablities to effectively run a nuclear powerplant at its safest and most effecient levels. "Nuclear Power Plants, World-wide." Weblog post. Welcome to ENS - European Nuclear Society.
European Nuclear Society. Web. 16 Aug. 2010. <http://www.euronuclear.org/info/npp-ww.htm>. Cross, Alasdair. "BBC News - Is Fusion Power Really Viable?" BBC News - Home. 5 Mar. 2010.
Web. 16 Aug. 2010. <http://news.bbc.co.uk/2/hi/science/nature/8547273.stm>. "Energy Resources: Nuclear Power." Andy Darvill's Science Site: Home. Web. 16 Aug. 2010.
<http://www.darvill.clara.net/altenerg/nuclear.htm>. "The Future of Nuclear Power." MIT. MIT. Web. 16 Aug. 2010.
<http://web.mit.edu/nuclearpower/>. Sofge, Erik. "MIT Fights for Clean Power With Holy Grail of Fusion in Reach - Popular Mechanics."
Automotive Care, Home Improvement, Tools, DIY Tips - Popular Mechanics. Popular Mechanics,
1 Oct. 2009. Web. 16 Aug. 2010.
<http://www.popularmechanics.com/science/4251982>. Internet Magazine Book Giancoli, Douglas C. "Nuclear Energy; Effects And Uses Of Radiation." Physics. 6th ed. New Jersey:
Pearson Education, 2005. Print.
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