Question

defination of Moderator in Nuclear Reactor

Answer 1

In nuclear engineering, a neutronmoderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235 or a similar fissile nuclide.

Answer 2

Moderator:-

→The most efficient fission reactions occur with slow neutrons. Thus, the fast neutrons ejected during fission must be slowed down by collisions with atoms of comparable mass that do not absorb them. Such materials are called moderators.

→The most commonly used moderators are ordinary water and graphite.

→The most efficient moderator is helium.

→The next most efficient one is heavy water (D20) but this is so expensive that it has been used only in research reactors.