METHOD FOR PRODUCING PELLETIZED URANIUM DIOXIDE FUEL Russian patent published in 2003 - IPC

FIELD: production of sintered pellets from ceramic nuclear fuel such as uranium dioxide. SUBSTANCE: method includes evaporation and hydrolysis of uranium hexafluoride. Pure wastes of uranium monoxide-oxide, and uranium dioxide with impurities complying with Standard Specifications are dissolved. Wastes of uranium monoxide-oxide, uranium dioxide, and uranium- containing process solutions polluted by impurities are also dissolved. Then ammonium polyurethane is extracted and re-extracted, settled down, filtered, dried out, and reduced. After that lot of uranium dioxide powder is completed, tested for sintering ability and postsintering density. Powder is mixed up with plasticizer, pellets are formed and ground. As a final procedure, pellets are subjected to quality control. Pure wastes of uranium monoxide-oxide and uranium dioxide are dissolved in solution of distilled water and nitric acid pure for analysis; upon filtering uranyl nitrate is settled down in ammonium-uranyl-tricarboxyl. The latter is calcined, reduced to uranium dioxide, tested for sintering ability, and mixed up with uranium dioxide produced through ammonium polyurethane. Ingredients are mixed up in proportions sufficient to obtain desired sintering. EFFECT: ability of producing adjustable-density pellets having steady properties. 3 cl, 1 dwg, 1 tbl