Abstract: A method and an arrangement for producing spherical fuel cores and/or breeder material cores by dripping a pouring solution containing uranyl nitrate and a solution containing at least one auxiliary agent into an ammoniacal precipitation bath to form microspheres, aging, washing, drying, and thermally treating the microspheres.

Abstract: A method for the production of spherical combustible or fertile material particles from an oxide of the group of the heavy metals uranium, plutonium, or mixtures thereof. For this purpose, the process steps of producing a base solution of the nitrates of the heavy metal(s), adding at least one first reagent in order to adjust the viscosity of the solution, dropping the solution to form microspheres, at least superficially solidifying the microspheres in an atmosphere containing ammonia, collecting the microspheres in a solution containing ammonia, and subsequent washing, drying and thermal treatment are carried out, where at least one of urea, ammonium carbonate, ammonium hydrogen carbonate, ammonium cyanate, and biuret are added to the base solution before adding the first reagent. The solution thus prepared is heated to a temperature T where 80° C.?T<Ts and where Ts=boiling temperature of the solution, and is maintained at the temperature over a time period t where 2 h?t?8 h.

Abstract: A method and an arrangement for producing spherical fuel cores and/or breeder material cores by dripping a pouring solution containing uranyl nitrate and a solution containing at least one auxiliary agent into an ammoniacal precipitation bath to form microspheres, aging, washing, drying, and thermally treating the microspheres.

Abstract: A method for the production of spherical combustible or fertile material particles from an oxide of the group of the heavy metals uranium, plutonium, or mixtures thereof. For this purpose, the process steps of producing a base solution of the nitrates of the heavy metal(s), adding at least one first reagent in order to adjust the viscosity of the solution, dropping the solution to form microspheres, at least superficially solidifying the microspheres in an atmosphere containing ammonia, collecting the microspheres in a solution containing ammonia, and subsequent washing, drying and thermal treatment are carried out, where at least one of urea, ammonium carbonate, ammonium hydrogen carbonate, ammonium cyanate, and biuret are added to the base solution before adding the first reagent. The solution thus prepared is heated to a temperature T where 80° C.?T<Ts and where Ts=boiling temperature of the solution, and is maintained at the temperature over a time period t where 2 h?t?8 h.

Abstract: A process for overcoating granules with overcoating material in a granulator by providing the inside surface of the granulator, before introduction of the granules, with a layer of the overcoating material in a thickness of 0.1 to 1 mm, maintaining a preset entrainment height of the granules during the granulation process, and adding the overcoating material in the flowing particle bed. The deposited layers are very uniform.

Abstract: Substantially isotropic spherical fuel and absorber elements for high temperature reactors are produced by molding corresponding fuel particles and graphite molding compositions. There is used as graphite molding powder a mixture of graphitized granules of coke and a hardenable resin binder. There are first produced in steel dies at 80.degree. to 120.degree. C. half shells and a nucleus with a pressed density of 1.0 to 1.4 g/cm.sup.3 followed by molding in a further steel die to the final format.

Abstract: To produce spherical fuel or absorber elements for high temperature reactors a mixture of coated nuclear fuel or absorber particles and graphite molding composition is molded into spheres, carbonized in a furnace having gas flushing and calcined in a vacuum. There are attained high throughputs without addition of transportation aides by employing as resin binders a thermosetting synthetic resin, hardening the resin at 110.degree. to 170.degree. C. and subsequently allowing the spheres to roll for 1 to 10 hours through an oven which is inclined around 2.degree. to 12.degree. to the horizontal. Thereby the oven must exhibit an increasing and decreasing temperature profile, the flushing gas introduced from both sides and be removed in a temperature zone of 400.degree. to 500.degree. C.

Abstract: Graphite molding powders are prepared which contain phenol-formaledehyde as a binder and which are intended for use in the manufacture of graphite molded articles, especially fuel inserts, fuel elements and absorber elements for high temperature reactors by mixing a graphite powder with a phenol formaldehyde binder and subsequent heat treatment, in a given case in admixture of coated fuel, fertile or absorber particles. The invention resides in not adding to phenol-formaldehyde as such to the graphite powder but as the starting components namely phenol and formaldehyde or source of formaldehyde and heating the mixture to the resin condensation temperature.