Abstract: The invention relates to a process for producing 228Th from a natural thorium salt, which comprises in succession: a) the separation of the radium from the other radioelements present in this salt, by at least one coprecipitation of the radium by barium sulphate, this coprecipitation comprising: i) the addition of sulphuric acid and a barium salt to an aqueous solution of said natural thorium salt in order to form a barium-radium sulphate coprecipitate and ii) the separation of the coprecipitate from the medium in which it has formed; b) the extraction of the thorium 228 coming from the decay of radium 228 from the coprecipitate thus separated; and, optionally c) the purification and concentration of the 228Th thus extracted. Applications: manufacture of radiopharmaceutical products useful in nuclear medicine, in particular in radioimmunotherapy for the treatment of cancers and AIDS.

Abstract: A chemical element to be very efficiently separated from uranium starting from an acid aqueous phase, in an extraction cycle for the uranium, when this chemical element is present in said phase at a concentration less than that of the uranium, or even as a trace element, and when it is moreover less extractable by the extractant used in this extraction cycle than is the uranium. The chemical element can notably be neptunium(IV) or thorium 228.

Abstract: The invention relates to a method constituting an improvement of the PUREX method, which makes it possible to obtain separation of uranium from the other actinides (Pu, Np, Th, . . . ) in a single purification cycle. This method successively comprises: a) co-extracting the uranium(VI), plutonium(IV) and other actinides(IV) or (VI) from an aqueous nitric solution by using solvent phase and scrubbing the latter; b) back-extracting the plutonium in oxidation state (III) from the solvent phase by using an aqueous nitric solution; c) back-extracting the uranium in oxidation state (VI) from the solvent phase by using an aqueous nitric solution; d) concentrating the aqueous nitric solution resulting from step c) with respect to uranium(VI); and it is characterized in that some of the uranium(VI)-concentrated aqueous solution obtained in step d) is used for back-extracting the actinide(IV) or actinides(IV) from the solvent phase during step b) or between steps b) and c).

Abstract: The invention relates to a process for producing 228Th from a natural thorium salt, which comprises in succession: a) the separation of the radium from the other radioelements present in this salt, by at least one coprecipitation of the radium by barium sulphate, this coprecipitation comprising: i) the addition of sulphuric acid and a barium salt to an aqueous solution of said natural thorium salt in order to form a barium-radium sulphate coprecipitate and ii) the separation of the coprecipitate from the medium in which it has formed; b) the extraction of the thorium 228 coming from the decay of radium 228 from the coprecipitate thus separated; and, optionally c) the purification and concentration of the 228Th thus extracted. Applications: manufacture of radiopharmaceutical products useful in nuclear medicine, in particular in radioimmunotherapy for the treatment of cancers and AIDS.

Abstract: A chemical element to be very efficiently separated from uranium starting from an acid aqueous phase, in an extraction cycle for the uranium, when this chemical element is present in said phase at a concentration less than that of the uranium, or even as a trace element, and when it is moreover less extractable by the extractant used in this extraction cycle than is the uranium. The chemical element can notably be neptunium(IV) or thorium 228.

Abstract: The invention relates to a method constituting an improvement of the PUREX method, which makes it possible to obtain separation of uranium from the other actinides (Pu, Np, Th, . . . ) in a single purification cycle. This method successively comprises: a) co-extracting the uranium(VI), plutonium(IV) and other actinides(IV) or (VI) from an aqueous nitric solution by using solvent phase and scrubbing the latter; b) back-extracting the plutonium in oxidation state (III) from the solvent phase by using an aqueous nitric solution; c) back-extracting the uranium in oxidation state (VI) from the solvent phase by using an aqueous nitric solution; d) concentrating the aqueous nitric solution resulting from step c) with respect to uranium(VI); and it is characterized in that some of the uranium(VI)-concentrated aqueous solution obtained in step d) is used for back-extracting the actinide(IV) or actinides(IV) from the solvent phase during step b) or between steps b) and c).

Abstract: The present invention relates to a method for the continuous separation of caesium, strontium and transuranium elements contained in sodium waste which comprises the use of NaTPB, and to a device for the implementation of this method. The method of the invention comprises, in line, the following steps: (a) filling at least one of at least two feed tanks with the waste; (b) analysis of the content of Cs+, Sr++, Na+ and transuranium elements in the waste; (c) pre-treatment, adapted in relation to analysis results, of the solution in the feed tank intended to insolubilise the strontium and transuranium elements; (e1) a first caesium separation treatment; and e1a) a second caesium separation treatment, the method being conducted in continuous manner by means of the alternate use of the feed tanks.

Abstract: The present invention relates to a method for the continuous separation of caesium, strontium and transuranium elements contained in sodium waste which comprises the use of NaTPB, and to a device for the implementation of this method.

Abstract: A process for treating an aqueous solution mainly containing nitric acid and hydrofluoric acid. The process involves distilling to provide an aqueous solution concentrated in nitric acid and hydrofluoric acid for the separation thereof, then separating by distillation.

Abstract: The invention relates to a process for the treatment of basic aqueous effluents containing plutonium and possibly uranium.According to this process, the effluents are concentrated by evaporation under reduced pressure, at a temperature such that plutonium precipitation is substantially avoided. Advantageously, the effluents are evaporated at a temperature of 50.degree. to 80.degree. C. for a time such that a concentration factor of at least 6 is obtained.Application to the treatment of aqueous effluents obtained by the alkaline washing of organic solvents used in installations for the reprocessing of irradiated nuclear fuels.