A great interactive diagram that illustrates how nuclear power plants work can be found here. Copious amounts of water are needed to run nuclear power plants. When heated through nuclear fission, water provides steam to produce electricity. However, water also acts as a coolant within the system. Water is a nuclear power plant’s Achilles’ heel. Droughts in states such as North Carolina are of a great concern, because droughts threaten the shut-down or scaling back of nuclear power plants.