Heavy water
Materials of the Heavy Water Systems of CANDU Reactors

Since it is used for both the primary coolant and the separate moderator, heavy water is a defining feature of the CANDU reactor. The properties of D₂O are similar to those of light water, H₂O, and have been compiled in the most comprehensive and up-to-date series by the International Association for the Properties of Water and Steam (IAPWS) (see, for example, ). Briefly, under ambient conditions, D₂O is ∼ 11 % denser and ∼ 24 % more viscous than H₂O ; it boils at 101.4 °C and freezes at 3.8 °C. Its neutronic properties...