bibi asked in Science & MathematicsPhysics · 1 decade ago

EXPLAIN NUCLEAR FISSION AND NUCLEAR FUSSIOn AND give the advantage of fussion over fission?

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  • DanE
    Lv 7
    1 decade ago
    Favorite Answer

    When writing your HW answer, don't use the CAPS LOCK and make sure you spell fusion

    Nuclear fission—also known as atomic fission—is a process in nuclear physics and nuclear chemistry in which the nucleus of an atom splits into two or more smaller nuclei as fission products, and usually some by-product particles. Hence, fission is a form of elemental transmutation. The by-products include free neutrons, photons usually in the form gamma rays, and other nuclear fragments such as beta particles and alpha particles. Fission of heavy elements is an exothermic reaction and can release substantial amounts of useful energy both as gamma rays and as kinetic energy of the fragments (heating the bulk material where fission takes place).

    Nuclear fission produces energy for nuclear power and to drive explosion of nuclear weapons. Fission is useful as a power source because some materials, called nuclear fuels, both generate neutrons as part of the fission process and also undergo triggered fission when impacted by a free neutron. Nuclear fuels can be part of a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.

    The amount of free energy contained in nuclear fuel is millions of times the amount of free energy contained in a similar mass of chemical fuel such as gasoline, making nuclear fission a very tempting source of energy; however, the waste products of nuclear fission are highly radioactive and remain so for millennia, giving rise to a nuclear waste problem. Concerns over nuclear waste accumulation and over the immense destructive potential of nuclear weapons counterbalance the desirable qualities of fission as an energy source, and give rise to intense ongoing political debate over nuclear power.

    --> http://en.wikipedia.org/wiki/Nuclear_fission

    In physics, nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy depending on the masses of the nuclei involved. Iron and nickel nuclei have the largest binding energies per nucleon of all nuclei and therefore are the most stable. The fusion of two nuclei lighter than iron or nickel generally releases energy while the fusion of nuclei heavier than iron or nickel absorbs energy; vice-versa for the reverse process, nuclear fission.

    http://en.wikipedia.org/wiki/Nuclear_fusion

  • gripp
    Lv 4
    3 years ago

    Explain Nuclear Fission

  • 1 decade ago

    I'll answer this as simply as I can:

    Fission:

    ======

    Take a large atom (high atomic number) and throw a neutron at it. It will break into two smaller atoms and some extra neutrons. These extra neutrons will hit the neighbouring large atoms which will cause them to break into smaller atoms releasing more neutrons etc. Advantages: Releases a lot of thermal energy, heavy elements can be 'easily' mined and last a long time. Disadvantages: Greenpeace is opposed.

    Fusion:

    =====

    Take two small atoms (like hydrogen and helium isotopes) and bang them into each other with enough force that the nucleii collide. They stick together and release themal energy. Advantages: Abundance of light elements on earth, no waste products, lots of energy produced. Disadvantages, can not currently be done sustainably on earth due to enourmous initially energy required for fusion reaction to start.

    PS: TOKOMAK is expected to provide the solution to the fusion riddle.

    PPS: If anyone starts to correct the physics here I'll be annoyed because I am well aware of how simplistic I have explained this.

    NOTE to South Park Forever: Cold fusion was proven to be a myth. Hydrogen bombs are not the only way to do hot fusion though. The tokomak I mentioned above is a device built to focus magnetic fields such that ionised fusion particles (hydrogen and helium isotope nucleii) can be controlled, accelerated and focused at one point in space. This should generate enough heat to power the tokomak and, hence, be self-sustainable energy system (the closest thing to man-made perpetual motion, because the system constantly needs refueling with hydrogen and helium isotopes). The next generation of tokomak will be aiming to generate more power than it uses so that a comercially viable fusion reactor can be built. The tokomak does not work by cold fusion and science fiction warp cores are completely irrelevent.

  • 1 decade ago

    Not quite right!

    When you split atomic nuclei, which are heavier than that of iron (more protons and neutrons), the resulting parts together are lighter than the whole.

    When you combine atomic nuclei, which are lighter than that of iron (less protons and neutrons), the resulting larger atomic nucleus (when still lighter than, or equals iron) will be lighter than all original constituents together.

    Iron nuclei have the least so-called bonding energy and cannot be made lighter by putting something to it or taking something away from it.

    - Fission: Split an Uranium- or Plutonium nucleus (both much heavier than Iron) and the resulting parts together are lighter than the nucleus you started with. See: http://en.wikipedia.org/wiki/Nuclear_fission

    - Fusion: Take 2 protons and 2 neutrons and stick those together, you'll end up with a Helium nucleus (much lighter than Iron), which is lighter than the sum of the original components together. Normally you take 1 Deuterium nucleus (1 proton and 1 neutron) and a Tritium nucleus (1 proton and 2 neutrons), which you can both call "heavy hydrogen". See: http://en.wikipedia.org/wiki/Deuterium , http://en.wikipedia.org/wiki/Tritium and http://en.wikipedia.org/wiki/Nuclear_fusion

    Deuterium and Tritium can be obtained from for instance "heavy water". See: http://en.wikipedia.org/wiki/Heavy_water

    According to the formula E=mc^2, this loss of mass results in a huge amount of nuclear energy.

    Advantages:

    - Fission: Easy to build power plants and control them.

    - Fusion: Clean energy: The resulting Helium is a natural chemically not reactive gas. (The only radiating stuff will be the container and cooling fluid afterward, but this is nothing compared with the waste of the present nuclear power plants, which also have this kind of waste, but mostly they sit on the fission products.

    And a meltdown, like what happened in Chernobyl, is not to be expected with fission reactors.).

    Disadvantages:

    - Fission: The existance of the Uranium- and Plutonium bombs. Dirty energy: You are left with dangerously radiating and poisenous stuff, the split parts. Mistakes and meltdowns are highly dangerous.

    It also takes a lot of effort to get enough of the proper kind (isotope) of Uranium or Plutonium for the purpose.

    - Fusion: The existance of the Hydrogen bomb. You need extreme temperatures to start nuclear fission. You cannot hold such material (plasma) in normal containers, only in special magnetic fields as generated in a Tokamak, a toroidal chamber of original Russian design.

    Obtaining Deuterium in large quantities is not really easy either.

    The most advanced Tokamak to date is in Culham near Oxford in the UK: the JET or the Joint European Torus. Now they start building the next generation experimental torus, the ITER in Cadarache in southern France. It will take 30 to 40 more years, before we can use power from such fusion plants.

    See: http://www.jet.efda.org/

    The sun (and all normal stars) are fusion reactors.

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  • Anonymous
    1 decade ago

    I guess you would generate a lot of HEAT if someone corrected your answers....8-) Presently, you need to set off a Nuclear FISSION device to initiate FUSION to liberate more energy. That is how HYDROGEN bombs work and why they give massive yields.

    That is HOT fusion. We want to learn how to do this in small quantities using COLD fusion, preferably at room temperature.

    STTOS talked about needing Magnetic Bottles in the Warp Drive and is surprisingly accurate for a TV show.

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