Which component is used uniquely in nuclear power plants to regulate the fission process?

Control rods are a vital component in nuclear power plants specifically designed to regulate the fission process. They are made of materials that absorb neutrons, such as boron, cadmium, or hafnium. In a nuclear reactor, the fission of uranium or plutonium produces additional neutrons, which can cause further fission reactions. Control rods can be inserted into or removed from the reactor core to either absorb more neutrons, thereby slowing down the reaction, or to allow more neutrons to cause fission, thereby increasing the reaction rate. By adjusting the position of these rods, operators can precisely control the power output of the reactor, ensuring safe and efficient operation.

In contrast, steam turbines, coal burners, and cooling towers serve different functions in power generation and are not specifically involved in controlling the fission process. Steam turbines convert thermal energy from steam into mechanical energy to generate electricity, coal burners are used in fossil fuel power plants for combustion, and cooling towers are utilized to dissipate heat from the system but do not participate in the nuclear fission reactions themselves.