Canadian heavy-water-moderated pressure tube natural uraniumUranium in the isotope composition occurring in nature, Natu... reactorSystem used to initiate, maintain and control a fission chai.... The name is made up of: “CAN” for Canada, “D” for the technical term deuteriumHydrogen isotope with a nucleus containing a neutron and a p... oxide i.e. heavy waterDeuterium oxide, D2O; water containing two deuterium atoms i... and “U” for the uraniumNatural radioactive element with the atomic number 92. The n... fuelSee 'nuclear fuel'..