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Generating Electricity using Nuclear Power.

What is Fission?

Nuclear power stations get their energy from a
type of nuclear reaction called fission.
Fission means splitting a big nucleus into smaller nuclei.
Fission is not the same process as fusion.
There are advantages and disadvantages in
using nuclear power to generate electricity.

Why is Energy Released when a Nucleus is Split?

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 (and fusion) 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 released from fission is used to generate electricity.

What is the Fuel for Nuclear Power Stations?

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 additional neutrons can be captured by
other atoms of uranium-235 and so the process continues.

What is a Chain Reaction?

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 these radioactive smaller nuclei
contribute to an ever increasing amount of radioactive waste.

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