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►Nuclear Energy:
Fission:
Fission is the splitting of certain
nuclei that are capable of undergoing this fission process.
Not all nuclei can undergo this process. Uranium 235 and Plutonium 239
are two isotopes that are fissionable.
Fission is effected by using slow neutrons as "bullets" that penetrate
the nuclei and physically fragment them.
The result are that fragments form with additional neutrons, and a great
deal of energy is released from the nucleus.
The released neutrons go on to split other nuclei which accelerates the
process. This is called a "chain reaction" and can get out of control if
the number of neutron bullets are not controlled.
The fragmented nuclei are usually radioactive themselves and emit
harmful radiation in the form of gamma radiation (very short wavelength,
lethal electromagnetic radiation), as well as alpha and Beta particles.
Alpha particles are Helium atoms that have been stripped of their two
electrons.
They are massive particles and have a charge of +2. Beta particles have
the same charge as an electron and the same mass.
The fragments usually have half lives of several thousands of years. The
half life of a radioactive isotope is the time that it takes for half of
the remaining atoms to undergo decay. With these half lives being
thousands of years, these by products become quite a problem as a lethal
waste product.
Partial solution to the waste problem is to design so called "breeder
reactors".
Although fission processes yield much more energy per mass of fuel
compared to the fossil fuels, it is still an exhaustible resource.
Fusion:
Nuclear fusion is the combining of
nuclei to produce larger atoms.
The fusion process is the source of stellar energy. Our own sun fuses
Hydrogen nuclei together to form Helium nuclei. The fusion process
produces very large amounts of thermal and radiant energy as a result of
converting a very small amount of Hydrogen into Helium.
The fusion process takes high temperatures and densities. The high
temperature and densities create a plasma where atoms have been stripped
of their electrons. . In the fusion process the energy to fuel mass
ratio efficiency is extraordinarily high compared even to the energy to
fuel mass ratio in a nuclear fission.
The fuel needed for the fusion process is water which covers 67% of the
earth's surface.
Furthermore, the products of fusion processes are non-radioactive. One
of the problems with producing a sustained controllable fusion process
is the conditions required for its initiation and propagation. To
initiate a fusion requires temperatures far in excess of the melting
point of any element or alloy. For this reason the fuel must be
contained in a strong magnetic field called a "magnetic bottle".
However, the problem is that it takes more energy expenditure to
initiate the process than the energy generated by it.
The next phase in the fusion projects is to reach what is called the
"break even point".
The fusion process would produce no harmful by products nor would it
empty harmful pollutants into the atmosphere.
Probably pilot fusion reactors or their prototypes will be available by
the year 2030 or 2050.
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Nuclear Energy -
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