Question

Explain the principle and working of a nuclear reactor with the help of a labelled diagram.

Answer 1

Nuclear reactor:
Principle: It works on the principle of achieving controlled chain reaction of Uranium ${}^{238}U$ enriched with ${}^{235}U$ and as a result generating huge amount of energy. The controlled chain is made possible by :

• slowing down the fission neutrons to thermal neutrons by using a moderator.
  
• inserting rods that can absorb neutrons(control rods) and use them to maintain the reaction rate.

Working:
Clearly explained in the image.

• In general the fuel used is ${}^{235}U$ which is filled in aluminium cylindrical rod.
• The moderator used are $D_{2}O$ heavy water, salt water and graphite block.
  
• The materials like Beryllium and Cadmium rods are used as control rods which controls the chain reaction by absorbing the neutron emitted in the nuclear reaction.
• Cold water is circulated through the water pipes surrounding ht nuclear reactor to absorb heat.