What is the role of a control rod in a nuclear reactor?

The role of a control rod in a nuclear reactor is to absorb neutrons. Control rods are usually made of materials that have a high neutron absorption capacity, such as boron or cadmium. In a nuclear reactor, the fission process involves the splitting of heavy atomic nuclei, which releases a significant number of neutrons. These neutrons can cause further fission reactions, leading to a self-sustaining chain reaction.

By placing control rods into the reactor core, operators can effectively manage the number of free neutrons available to sustain the reaction. When the control rods are inserted into the reactor, they absorb some of the neutrons, thereby reducing the probability of additional fission events. This allows for precise control over the reactor’s power output and ensures that the reaction can be safely maintained at desired levels.

If there are too many neutrons, the reaction may become too energetic, which is dangerous. Conversely, if there are too few neutrons, the fission process could halt, leading to a shutdown of the reactor. Hence, the absorption of neutrons by control rods is crucial for manipulating and stabilizing the nuclear reaction within the reactor.