What chemical coolants in nuclear power plants?
Examples: water, heavy water, organic compounds, sodium, lead,
The coolants prevent overheating caused by the uranium rods. The process by which nuclear plants work is through the heating of water, which turns into steam and drives the shaft, which in turn creates current. Without coolant the rods would overheat and cause an explosion (like the one seen in Japan, or Chernobyl), thus creating a danger of radiation and causing great danger to the human population.