Properties and Functions of Moderator in Nuclear Reactor
Properties of Good Moderator :
- The moderator must not absorb neutrons itself. This means it should have a relatively low neutron absorption cross-section.
- The moderator should efficiently slow down the neutrons.
- It should be in pure form.
- It should be thermally stable.
- It should have good heat conducting property.
Function of moderator :
A moderator is a material used in a nuclear reactor to slow down the neutrons produced from fission. By slowing the neutrons down the probability of a neutron interacting with Uranium-235 nuclei is greatly increased thereby maintaining the chain reaction. Moderators are made from materials with light nuclei which do not absorb the neutrons but rather slow them down by a series of collisions. The moderator is made up of graphite or heavy water or beryllium.