Abstract: Production of mixed-oxide nuclear fuel pellets of uranium dioxide (UO.sub.2+x) and plutonium dioxide (PuO.sub.2) which are soluble in nitric acid. The powder mixture of oxides is added to a halogen-free milling aid, such as propane diol, then is milled and subsequently granulated, pressed and sintered. The milling aid is expelled by subsequent drying processes or heat treatments (sintering). The milling process is controlled to obtain a primary grain size of less than two micrometers.

Abstract: Method for producing molded blanks of ceramic powder, for instance, nuclear reactor fuels such as UO.sub.2, PuO.sub.2, ThO.sub.2 or (U/Pu)O.sub.2 -mixed oxides in powder form in a mold belonging to the molding device. The device has a die with a hole and a plunger with a head movable in this hole relative to this die, by which the wall of the hole is lubricated with a lubricant, characterized by the feature that a paste and/or wax-like substance, preferably a lubricating grease is used as the lubricant and that it has a dripping point which is higher than the operating temperature of the mold.

Abstract: Production of UO.sub.2 nuclear fuel pellets containing PuO.sub.2 in set amounts, which pellets are soluble in nitric acid and suitable for reprocessing without the aid of a special additive. Uranium oxide powder is mixed with 15 to 50% by weight of the mixture of plutonium oxide powder; the mixture milled and pressed into pellets. The pellets are sintered, comminuted, pressed to form pellets and the pellets comminuted to free-flowing granules. The free-flowing granules are mixed with UO.sub.2 granules to obtain a desired UO.sub.2 /PuO.sub.2 ratio, and the mixture pressed into pellets and sintered to form UO.sub.2 nuclear fuel pellets containing PuO.sub.2 soluble in nitric acid.