Q. Which of the following material is used to make control rods in a nuclear reactor?
a. Indium
b. Boron
c. Cadmium
d. All of the above
The reaction rate is controlled through control-rods made out of neutron-absorbing materials. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning.