Explain nuclear reactor?

Nuclear Reactor

• Nuclear reactors are useful in producing electricity.
• A nuclear reactor is an arrangement to generate electricity whichmakes use of nuclear fission.

Requirements for controlled nuclear fission in reactor:

1. Neutrons to be slowed down.

• Neutrons are slowed down by using moderators which are lighter nuclei which slow down fast moving neutrons by elastic collision.
• Commonly used moderators:-

1.Water

1. Heavy Water
2. Graphite

• Consequence of use of moderators:-
  1. Multiplication factor of neutrons increases: - When a neutron hits a target nucleus along with daughter nucleus,it produces 3 neutrons.These 3 neutrons are highly energetic but they need to be slowed down, so they can hit the target nucleus.
  2. As a result high multiplication factor results in uncontrolled chain reaction.