What is the purpose of control rods in a nuclear reactor?

The purpose of control rods in a nuclear reactor is to control the number of fission reactions occurring within the reactor core. Control rods are made from materials that absorb neutrons, such as boron or cadmium. By inserting or withdrawing these rods from the reactor core, operators can effectively manage the rate of fission reactions.

When control rods are pushed deeper into the reactor, they absorb more neutrons, which leads to fewer neutrons available to sustain the fission process. This reduces the reaction rate and can help prevent overheating. Conversely, when the control rods are withdrawn, there are more free neutrons available to initiate fission, effectively increasing the reaction rate.

This mechanism is crucial for maintaining a steady and safe operation of the nuclear reactor, allowing it to provide a controlled release of energy for electricity generation or other purposes.