Abstract: A nuclear fuel green compact is produced by sintering in an atmosphere of reducing gas. A mixed gas of hydrogen and nitrogen to which water vapor is added is used as the reducing gas. By establishing the amount of water vapor added to the mixed gas of hydrogen and nitrogen so that dew point as an indicator is -15.degree. C. or more, the nitrogen content of the produced pellets can be controlled to be equal to or less than 0.0075 wt %.

Abstract: A process for preparing uranium tetrafluoride by reacting a uranous solution with a hydrofluoric acid solution in a fluorination precipitation tank is provided. A cylindrical inner tube having upper and lower ends opened is disposed in the tank in the longitudinal direction thereof. An agitator is arranged within the inner tube to generate a descending or ascending stream inside the inner tube and a ascending or descending stream outside the inner tube, thereby producing a circulation of reaction liquor in the tank. The uranous solution and the hydrofluoric acid solution are introduced into the tank from the upper part thereof and the produced uranium tetrafluoride crystals are withdrawn from the lower part of the tank together with a part of the reaction mother liquor. The amount of the hydrofluoric acid solution added to the uranous solution is adjusted so that the fluorine concentration in the reaction mother liquor in the tank is maintained at 2 to 4 g/l.

Abstract: There is disclosed a method for removing oxides of nitrogen from gaseous mixtures by contacting the gaseous mixtures with an alkaline solution of an alkali metal manganate.