Nuclear Energy - Energie EDF

Heat source:
nuclear fi ssion
During the nuclear fi ssion
process, an uranium atom is
bombarded with a neutron.
When the nucleus splits, it
releases two or three neutrons
which in turn collide with other
nuclei. This process is known as
a chain reaction, which
generates heat.
NUCLEAR FISSION PROCESS
Neutron Noyau fissile Nouveaux Neutrons
noyaux
Neutron Fissile New nuclei Neutrons
nucleus
Nuclear fuel: uranium. Uranium 235 is used as fuel as it is the only fi ssile
atom (capable of undergoing fi ssion) occurring in nature. In nature, it
occurs in insuffi cient quantities. It therefore has to be enriched in order
to increase the number of atoms. This uranium is then converted into
uranium oxide, used as fuel on nuclear power plants. Prior to combustion,
FUEL ROD AND FUEL ASSEMBLY
the uranium oxide is
compressed into
Cladding Gaine Pastille d’uranium Enriched
uranium enrichie pellet
Ressort Spring
cylindrical pellets that are
enclosed in sealed metal
cladding and placed in
tubes known as fuel rods.
4 m
These are grouped
together in fuel
assemblies and placed
inside the reactor.
Base Plaque de pied
plate
Tube guide Guide
tube
Grappe Control Araignée Spider
de commande rod assembly
The core contains 150 to
200 fuel assemblies.
INSIDE THE ATOM
The nucleus of an atom, the
smallest particle of a single
body, consists of protons
(positive electrical charge)
and neutrons (no electrical
charge). An atom has an
equal number of neutrons
and protons, but an isotope
may have a different
number of neutrons.
Power plant
operation
A power plant is
operated from a main
control room. In order to
increase or decrease the
amount of power
generated, control-room
operators use control
rods to adjust the
intensity of the chain
reaction. In abnormal
operating conditions, the
rods drop automatically
and shut down the
reactor within the space
of a few seconds.
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