Nuclear Energy

Atoms are so small that they can’t be seen except with the help of an electron microscope.
An atom is roughly 0.1 nanometers, that is, 0.000,000,0001 meters. In other words, if we make a
tiny dot with a pencil, a dot of roughly 1 mm in size, then this dot would have ten million, or one
crore, atoms.
Every element is characterised by its atomic mass number and atomic number. The mass
number A of an element is the total number of nucleons, that is, the total number of neutrons and
protons contained in its nucleus; the atomic number Z is the number of protons. The atomic number
of an element (that is, the number of protons in it) determines its chemical properties and its place
in the Periodic Table. Hydrogen has the lowest periodic number (Z =1) whereas uranium has the
highest atomic number among the naturally occurring elements (Z = 92). Elements with higher
atomic numbers, like Neptunium (Z=93) and Plutonium (Z = 94) have been created artificially. xlviii
The chemical properties of an atom depend upon the number of protons in it, that is, its
atomic number. There are atoms whose nuclei have the same number of protons, but different
number of neutrons. The chemical properties of these atoms are identical, since they have the same
number of protons. Such atoms are called isotopes. An isotope is designated by its element symbol
with the mass number as superscript; for instance, the three isotopes of uranium are designated as
U 234 , U 235 and U 238 . (It can also be written by writing the mass number after the element symbol,
such as U-235).
Nuclear Fission
Fission means splitting. When a nucleus fissions, it splits into several lighter fragments.
Nuclear fission can take place in one of two ways: either when a nucleus of a heavy atom captures a
neutron, or spontaneously. The fragments, or fission products, are about equal to half the original
mass. Two or three neutrons are also emitted. The sum of the masses of these fragments (and
emitted neutrons) is less than the original mass. This 'missing' mass (about 0.1 percent of the
original mass) has been converted into energy.
The amount of energy released in this process can be
obtained from Einstein's famous equation E = mc 2 , where E is
energy, m is mass and c is the speed of light (approximately
300,000 kilometers per second). The concept behind this
equation is simple: that matter and energy are essentially
interchangeable – matter can be converted into energy, and
energy can be converted into matter.
Typical fission events release about 200 million eV (electron volts) for each fission event,
that is, for the splitting of each atom. By contrast, when fossil fuel like coal is burnt, it releases only
a few eV as energy for each event (that is, for each carbon atom). This is why nuclear fuel contains
so much more, millions of times more, energy than fossil fuel. To get an idea of the energy released
in a fission reaction: the energy found in half a kilogram of uranium is equivalent to 4.2 million
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