What is meant by controlled nuclear fission ? Write an important application of it. [1+1]

Controlled nuclear fission refers to the process in which the nuclear fission reaction is sustained at a steady rate by controlling the number of neutrons available to cause further fission. In this process, a chain reaction is maintained by using moderators (like heavy water or graphite) to slow down fast-moving neutrons and control rods (like boron or cadmium) to absorb excess neutrons. This ensures that the reaction neither runs away (uncontrolled) nor stops (subcritical).

An important application of controlled nuclear fission is the generation of electricity in nuclear power plants. In a nuclear reactor, the heat produced from controlled fission is used to convert water into steam, which drives turbines connected to generators, producing electricity efficiently and with minimal greenhouse gas emissions.