Control rods are essential components in nuclear reactors, used to manage the fission process. Made from materials that absorb neutrons, such as boron or cadmium, they help regulate the rate of nuclear reactions by controlling the number of free neutrons available to sustain the chain reaction. When inserted into the reactor core, control rods absorb neutrons, reducing the likelihood of further fission events. Conversely, withdrawing them allows more neutrons to cause fission, increasing the reactor's power output. This precise control is crucial for maintaining safety and efficiency in nuclear energy production.