Liquid sodium is used in Nuclear reactors. Its function is

CONCEPT:

Nuclear reactor:

• In a nuclear reactor, the energy is generated by a nuclear fission reaction.
• In a nuclear reactor, there is a concrete chamber and in this concrete chamber, there is a steel vessel. In this steel vessel, the nuclear fission reaction takes place.
• Fuel rods: Fuel rods are placed inside the steel chamber.
  • These rods are made of fissionable material. Generally, fuel rods are made of uranium-235, thorium, etc.
• Moderator: It is used to decrease the speed of fast-moving neutrons.
• Control rods: These rods are placed between the fuel rods. It is used to control the chain reaction. Control rods are generally made of cadmium.
  • The nuclear reactors are controlled by means of control rods which are made of a strongly neutron-absorbent material such as boron or cadmium (Cd).
• Coolant: It is used to absorb heat produced during the reaction.

EXPLANATION:

• Liquid sodium takes up heat released from the nuclear reactor and transfers it to water which generates steam, which is used to run the turbine to generate power.
• So liquid sodium acts as a heat exchanger. Hence, option 2 is correct.