What types of water are used in nuclear reactors and in what quantities?
Ordinary water and heavy water are used in nuclear reactors. Whereas ordinary water is а compound of hydrogen and oxygen, heavy water is а compound of heavy hydrogen and oxygen. The nucleus of an atom of heavy hydrogen consists of а proton and а neutron, while the nucleus of an atom of ordinary hydrogen consists of а proton only. Light Water Reactors use ordinary water as moderator and coolant but need enriched uranium as fuel. Light Water Reactors are of two types – Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs). Heavy Water Reactors use heavy water as moderator. An important type of heavy water reactor is the Pressurized Heavy Water Reactor (PHWR), which uses heavy water as moderator and coolant and can use natural uranium as fuel. About 180 t of heavy water inventory is required for а 220 MWe PHWR.
