Gesellschaft Fur Kernforschung M.b.h.

Kernforschungszentrum Karlsruhe Gmbh

Herbert Koschorke

Friedrich Kaufmann

Stefan Drobnik

Hartmut Seiffert

Siegfried Weisenburger

Werner Hild

Jaroslav Saidl

Dieter Sienel

Karl-Heinz Weiss

Method and device for effecting radioactive offgas filtration by means of a mass of filter material, and filter material regeneration, at temperatures in excess of 500.degree. C. in which substances to be filtered impinge on the filter material mass in at least one direction, filtration being effected by removing a layer of contaminated filter material in the direction opposed to the direction in which substances impinge on the filter material in order to remove the filtered substances for filter cleaning. Removal of the contaminated filter material is carried out by adding a fluxing agent to the filter material at operating temperatures for regenerating the filter material by means of a cleanup melt. This fluxing agent may be a glass frit, an alkali hydroxide or an alkali or alkaline earth metal salt.

Method of radioactive offgas filtration and filter regeneration and

Method for the solidification, in a manner which protects the environment against contamination, of waste materials obtained during reprocessing of irradiated nuclear fuel and/or breeder materials in a matrix of borosilicate glass. Highly radioactive solutions or slurries containing the waste materials in dissolved or suspended form are evaporated in a vessel in the presence of glass former substances until they are dry, the dry residue is calcinated and the calcinate is melted together with the glass formers while the waste gases are discharged to the environment. The waste liquid is obtained from a reprocessing system without pretreatment, is mixed with glass formers and a reduction agent and then is introduced in a controlled, continuous manner into the center of a borosilicate glass melt disposed in a melting crucible at a temperature in the region of 1000.degree. to 1400.degree. C. to form an island-like drying and calcinating zone on the surface of the melt while avoiding contact of the waste liquid with the walls of the crucible. A reducing atmosphere is formed and the presence of components in the waste gas which would radiologically and/or chemically contaminate the environment are substantially avoided.

Method for noncontaminating solidification of radioactive waste materials

A method for processing aqueous radioactive wastes for noncontaminating and safe handling, transport and final storage wherein nitric acid and/or nitrate containing aqueous radioactive waste solutions are continuously denitrated with formic acid, spray-dried and calcinated in a spray dryer having a spray nozzle surrounded by a reaction chamber, the resulting calcinate is mixed with glass former substances, the mixture is melted and the melt is caused to solidify into a glass, glass ceramic or glass ceramic-like block and the waste gases produced during denitration-drying and calcination are conducted through a filter system in order to remove solid particles that have been carried along by the gas. The process steps of denitration, drying and calcination are effected simultaneously and are terminated with the aid of and the intimate energy exchange in the fine distribute droplets superheated steam in the vicinity of the spray nozzle. The resulting waste gases are cleaned within a filter chamber surrounding the reaction chamber with the spray nozzle. An apparatus is provided for practicing the method.

Method and apparatus for processing aqueous radioactive wastes for

Method for preventing malfunctions in the solidification of radioactive wastes contained in an aqueous waste solution in a glass, glass ceramic or glass ceramic-like matrix wherein the wastes are spray-dried and calcinated. Diatomaceous earth or diatomaceous earth-like substances in solid form are added to the aqueous waste solution before the spray drying step in quantities of 45g/l to 70g/l and in grain sizes of which more than 85 percent by weight of the grain size distribution are grain sizes from 6 to 75.mu..

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Stutensee-Friedrichstal, Germany

Herbert Koschorke