i) Function of Moderator :- Moderator is to moderate or reduce the speed of fast neutron to help the fission process.
ii) Function of sheilding : Shielding is to protect environment, humans and animals from the harmful radioactive radiation (pollution).before they are emitted to atmosphere from reactor. /
OR
The function of shielding is to absorbs nuclear radiation (α, β, γ) before they are emitted from reactor to atmosphere In this way it protect the operator from harmful effect due to nuclear radiation and also avoid radioactive air pollution.
iii) Function of Control Rod: Function of control rod is to be regulate fission process by absorbing the neutron. The control rod is inserted into the reactor core from top of the reactor vessel.
OR
The function of control rod is to control the chain reaction in reactor core by adjusting its height
iv) Function of Coolant: The function of coolant is to absorbs heat from reactor core and transfer it in heat exchanger for producing steam at high pressure and temperature.