Which of the following terms is NOT related to nuclear power plants? 

Explanation:

• An electrostatic precipitator is a device used to remove particulate matter (dust and pollutants) from industrial flue gas streams, typically in the context of thermal power plants or industrial processes.
• It is not directly associated with nuclear power plants.
• The other three terms—control rod, nuclear reactor, and moderator—are all directly related to nuclear power plants. Control rods are used to control the rate of fission reactions in the reactor, the nuclear reactor itself is the core where nuclear reactions take place, and a moderator is a substance used to slow down neutrons and enhance the probability of nuclear reactions.