Control Rod

Hi.Today we would like to talk about control rod.As mention before,control rod is one of the main component of nuclear reactor.As we all know,the nuclear power plant can generate the tremendous power,heat and energy through the nuclear fission.However,we need to control it in predictable manner.The failure of controlling control rod will cause the incident like the Chernobyle disaster and Stationary Low-Power Reactor Number One explosion.Control rod can be made using chemical elements which can control the rate of fission of uranium.

Actually,why the nuclear reactor need to control? It is important to make sure the reaction is sustained rather than to start the chain reaction.In case of emergency situations such as a sudden mechanical or structural damage, the reactor needs to be shut down quickly in order to prevent any major disaster like Chernobyl which could be very costly in terms of loss to life and environment.Without having the nuclear reactor in control, the control rod might be melted down. 

The control rod can absorb the amount of neutron to control the nuclear fission reaction.So the material being used in control rod must having high neutron absorbing capacity. Commonly material used are cadmium, boron, iridium and hafnium. For PWR nuclear reactor,the control rod is place on top of reactor but for BWR nuclear reactor,it is place at the bottom. This is because the stim generated inside the BWR reactor will push the control rod if control rod is place on top.