Types

• Atoms of some heavy elements, such as uranium, break apart when bombarded with neutrons in a process called nuclear fission. Nuclear fission converts mass to energy in a ratio given by the formula E = mc^2; because c is the speed of light, a tiny amount of mass produces a huge amount of energy.
  
  

Function

• In a power plant, the energy released by the nuclear reaction heats coolant water flowing through the reactor. Coolant water passes the heat to water in a heat exchanger, turning the water to steam.
  
  

Effects

• Steam from the heat exchanger rotates a turbine connected to a generator, which produces electricity. The steam condenses as it passes its remaining heat to cooling water. The condensed steam returns to the heat exchanger, while the cooling water passes to cooling towers--the funnel-shaped concrete towers often visible near nuclear power plants by lakes or oceans.