ceramic material, in particular, fissile material for nuclear reactor fuel

摘要

1285190 Uranium dioxide UNITED KING- DOM ATOMIC ENERGY AUTHORITY 2 Dec 1969 [16 Dec 1968] 59814/68 Heading C1A [Also in Division G6] A sintered polycrystalline ceramic fissile material consists of uranium dioxide containing a dispersed additive which is soluble in hyperstoichiometric uranium dioxide but insoluble in hypostoichiometric uranium dioxide. Magnesium oxide in an amount of 0À15 to 3À7% may be introduced by pressing a mixture of UO 2 and MgO powders into pellets and sintering in an oxidizing CO 2 /H 2 atmosphere to form hyperstoichiometric uranium dioxide; the MgO is released from solution by reduction of the UO 2 to the stoichiometric state. Alternatively ammonium diuranate is precipitated with 1% aluminum hydroxide, and the precipitate is calcined, sintered in an oxidizing atmosphere and then reduced in hydrogen. Reference is also made to the addition of scandium oxide.