Process for the preparation of mixed oxides of uranium-thorium and of uranium-plutonium soluble in nitric acid

摘要

1. A process for the production of homogeneous, freeflowing uranium/thorium and uranium/plutonium mixed oxide powders soluble in nitric acid from corresponding nitrate salt solutions of these heavy metals, characterized in that the solution is concentrated by evaporation to a concentration of 1000 to 1250 g heavy metal/l and subsequently sprayed onto ceramic beads of a stirred-bed reactor at a temperature in the range from 200 to 600 degrees C and the powder formed is subsequently reduced to (U, Th)O2 or (U, Pu)O2 with hydrogen or hydrogen/steam at 500 to 1500 degrees C.