Headings Radioactivity Search
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Nuclear Power - Generating Electricity.
Nuclear power stations get their energy
from a type of nuclear reaction called
fission.
Fission means the splitting of a big
nucleus into smaller nuclei.
Fission is the opposite of fusion.
A large
amount of energy is
released when the nucleus is split,
much larger than the amount of
energy in a chemical bond.
If you add up the mass of the nuclei before and after fission,
you find that some mass has
gone missing.
The process of fission destroys a
little bit of mass.
This little bit of mass turns into a large
amount of energy.
The amount of energy can be calculated using Einstein's
equation E = mc2
where E is energy, m
is mass and c is the speed
of light.
The energy is used to boil water to make steam.
Nuclear power stations use
either uranium-235 or plutonium-239.
Most
nuclear power stations use
uranium as their fuel
but the process of fission described below is the same
for both.
Uranium-235 can capture a
neutron and become uranium-236.
Uranium-236 is unstable and splits to form 2 smaller
nuclei
(called daughter nuclei)
plus an additional 2 or
3 neutrons.
These neutrons can be captured
by other atoms
of uranium-235 and
so the process continues.
The type of process where one
atom splits to release neutrons
which then cause other atoms to
split which release more neutrons
which cause other atoms to
split and so on is called a
chain reaction.
A moderator
and control
rods in the reactor core
are used to control the speed
of the chain reaction.
The smaller
nuclei produced by fission are
themselves radioactive
and contribute to an ever increasing
amount of radioactive
waste.
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