Heavy water is deuterium oxide or D20. It is chemically the same as normal water (H20) but the hydrogen atoms are of the heavy isotope deuterium in which the nucleus contains a neutron in addition to proton found in the nucleus of any hydrogen atom. India is the world’s second largest producer of heavy water.
Heavy water is used as coolant as well as moderator in pressurized Heavy Water Reactors. Apart from this polio vaccine can also be preserved in Heavy Water (D20). In Pressurized Heavy Water Reactor heat is produced when neutrons strike uranium atoms causing them to undergo fission in a continuous chain reaction.
In a pressurized heavy wafer reactor, the heat is removed from the reactor by water flowing in a closed pressurized loop. The heat is further transferred to second water loop through a heat exchanger. The second loop is kept at allowing pressure, allowing the water to boil and create steam which is used to turn the turbine generator and produce electricity.