a) Nuclear fuel: It is the fissionable material used in a reactor. It is in the form of rods
placed in a regular array in a large container.
Ex: Enriched uranium 235, Plutonium
b) Control rods: They are used to absorb the neutrons. Ex: Cadmium, Boron carbide.
c) Moderator: They are used to slow down the neutrons emitted in the fission process.
Ex: Heavy water & graphite.
d) Reflector: It is used to keep the neutrons confined to the core. Graphite or heavy water
can be used as reflector.
e) Coolant: It is used to continuously remove the heat released during the fission process.
The heat is transferred to a heat exchanger.
Ex: Liquid sodium, hydrocarbons with high boiling point, heavy water.
f) Radiation shield: It is used to protect the people in the vicinity of the reactor against the
harmful effects of nuclear radiations. Ex: Lead
g) Heat exchanger: It is used to transfer the heat energy of the coolant to convert water
into steam.