Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie Atomique

Areva Nc

Compagnie Generale Des Matieres Nucleaires

Orano Cycle

Pascal Baron

Manuel Miguirditchian

Binh Dinh

Christian Sorel

Xavier Heres

Michel Masson

Gilles Bernier

Laurence Chareyre

Francois Drain

Cécile Marie

Michael Lecomte

Didier Saudray

Patrick Pochon

Bernard Mauborgne

François Poncelet

Philippe Moisy

Gaëlle Milanole

Sylvain Costenoble

Clément Hill

Laurent Venault

Vincent Vanel

Jean Luc Emin

Philippe Pradel

Jean-Luc Emin

Michaël Lecomte

Sandra Lopes Moreira

Isabelle Bisel

Jean Bertin

François Drain

Novel dissymmetric N,N-dialkylamides which meet the following formula (I): where R represents a linear or branched alkyl group at Cto C. A method for synthesizing these N,N-dialkylamides, and to the uses of same as extractants, alone or in admixture, in order to extract uranium and/or plutonium from an aqueous acid solution, or to totally or separate uranium from plutonium from an aqueous acid solution and, in particular, an aqueous solution resulting from dissolving spent nuclear fuel in nitric acid. Further, a method for processing an aqueous solution resulting from the dissolution of a spent nuclear fuel in nitric acid, allowing the uranium and plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle, without requiring any plutonium reduction operation, and in which one of the aforementioned N,N-dialkylamides or a mixture of same is used as extractant. Applications for the method include the processing of spent nuclear fuels, in particular comprising uranium (e.g. UOX) or uranium and plutonium (e.g. MOX).

Dissymmetric N,N-dialkylamides, the synthesis thereof and uses of same

A method for the treatment of an aqueous solution resulting from the dissolution of a spent nuclear fuel in nitric acid, allowing the uranium and plutonium contained in the solution to be extracted, separated and decontaminated in a single cycle, without requiring any operation involving a reductive stripping of plutonium. Applications for the method include the processing of uranium-based and/or plutonium-based spent nuclear fuels.

Method for the treatment of an aqueous nitric solution resulting from dissolving spent nuclear fuel, said method being performed in a single cycle and without requiring any operation involving reductive stripping of plutonium

A method using diglycolamide for increasing the separation factor between americium and curium and/or between lanthanides during an extraction operation. The operation comprising putting an acid aqueous phase, in which are found the americium, curium and/or lanthanides, in contact with an organic phase non-miscible with water, containing at least one extractant in an organic diluent. The aqueous and organic phases are then separated, and the diglycolamide is added to the aqueous phase. This method can be used for processing and recycling irradiated nuclear fuels, in particular for selectively recovering americium from high activity aqueous solutions such as raffinates stemming from the processing of irradiated nuclear fuels with a PUREX or COEX&#x2122; method; processing of rare earth ores of the monazite, xenotime or bastnaesite type, in order to facilitate separation of &#x3c;&#x3c;lightweight&#x3e;&#x3e; rare earths from &#x3c;&#x3c;heavy&#x3e;&#x3e; rare earths and of yttrium, or that of two rare earths with adjacent or close atomic numbers.

Increase in the separation factor between americium and curium and/or between lanthanides in a liquid-liquid extraction operation

A method with which uranium from a natural uranium concentrate may be purified, including The extractant is an N,N-dialkylamide and the ratio between the flow rate at which the organic phase obtained at the end of step b) and the aqueous phase A3 circulate in the apparatus where step c) occurs, is greater than 1.

Method for purifying the uranium from a natural uranium concentrate

The invention relates to a process for reprocessing spent nuclear fuel which, among other advantages, does not require a plutonium-reducing stripping operation. This process finds particular application in the processing of uranium oxide fuels and uranium and plutonium mixed oxide fuels.

Process for reprocessing spent nuclear fuel not requiring a plutonium-reducing stripping operation

The invention relates to a process which makes it possible to separate together all the actinide(III), (IV), (V) and (VI) entities present in a highly acidic aqueous phase from fission products, in particular lanthanides, also present in this phase by using a solvating extractant in a salting-out medium. Applications: reprocessing of irradiated nuclear fuels, in particular for recovering plutonium, neptunium, americium, curium and possibly uranium, present in the form of traces, in a pooled but selective fashion with regard to lanthanides, from a solution for the dissolution of an irradiated nuclear fuel, downstream of a cycle for the extraction of uranium.

Pooled separation of actinides from a highly acidic aqueous phase using a solvating extractant in a salting-out medium

A method with which americium may be selectively recovered from a nitric aqueous phase containing americium, curium and fission products including lanthanides and yttrium, but which is free of uranium, plutonium and neptunium or which only contains these three last elements in trace amounts. The method is applicable for treatment and recycling of irradiated nuclear fuels, in particular for removing americium from raffinates stemming from methods for extracting and purifying uranium and plutonium such as the PUREX and COEX&#x2122; methods.

Method for selectively recovering americium from a nitric aqueous phase

The invention relates to a process for collectively separating all the actinides (III), (IV), (V) and (VI) present in a strongly acidic aqueous phase, from the fission products, and in particular from the lanthanides, which are also present in this phase, using two extractants that operate in unconnected chemical fields. Applications: reprocessing of irradiated nuclear fuels, especially to recover plutonium, neptunium, americium, curium and, possibly, uranium present in trace amounts, in a grouped manner but selectively with respect to the lanthanides, from a solution for dissolution of an irradiated nuclear fuel, downstream of a uranium extraction cycle.

Grouped separation of actinides from a strongly acidic aqueous phase

The invention relates to the use of butyraldehyde oxime as an anti-nitrous agent in a plutonium stripping operation based on a reduction of this element from oxidation state (IV) to oxidation state (III). Applications: any nuclear fuel reprocessing process in which employing a compound that has the twofold property of being extractable into an organic phase and of being capable of destroying the nitrous acid therein may be useful and especially any process including one or more operations for the reductive stripping of plutonium.

Use of butyraldehyde oxime as an anti-nitrous agent in an operation for the reductive stripping of plutonium

A method for treating spent nuclear fuel, which includes first decontaminating the uranium, plutonium and neptunium found in a nitric aqueous phase resulting from dissolving the nuclear fuel in HNO. The uranium, plutonium and neptunium found in the solvent phase is then split in a first aqueous phase and a second aqueous phase. Next, the first aqueous phase is stored. Following, the plutonium or other mixtures found in the first aqueous phase is purified relative to the fission products still found in said phase, in order to obtain, at the end of said purification, an aqueous solution containing a mixture of Pu and U or Pu, U and Np. Finally the resulting mixture of Pu and U or the mixture of Pu, U and Np is co-converted into a mixed oxide.

Method for treating spent nuclear fuel

The invention relates to a process for reprocessing a spent nuclear fuel and for preparing a mixed uranium-plutonium oxide, which process comprises: Applications: reprocessing of nuclear fuels based on uranium oxide or on mixed uranium-plutonium oxide.

Process for reprocessing a spent nuclear fuel and of preparing a mixed uranium-plutonium oxide

The invention relates to a method for separating uranium(VI) from one or more actinides selected from actinides(IV) and actinides(VI) other than uranium(VI), characterized in that it comprises the following steps: a) bringing an organic phase, which is immiscible with water and contains the said uranium and the said actinide or actinides, in contact with an aqueous acidic solution containing at least one lacunary heteropolyanion and, if the said actinide or at least one of the said actinides is an actinide(VI), a reducing agent capable of selectively reducing this actinide(VI); and b) separating the said organic phase from the said aqueous solution. Applications: reprocessing irradiated nuclear fuels, processing rare-earth, thorium and/or uranium ores.

Method for separating uranium (VI) from actinides(IV) and/or actinides (VI) and its uses

The invention concerns a cyclic method for separating at least one chemical element Efrom at least one chemical element Efrom an aqueous solution containing said elements, which employs a mixture of two extractants operating in non-overlapping chemical fields. Each cycle of said method comprises: a) co-extracting elements Eand Eby means of an organic phase containing a first extractant suited to causing the migration of said elements into said organic phase; b) adding to the organic phase a second extractant suited to selectively retaining the element(s) Ein said organic phase during step c): c) selectively stripping the element(s) Efrom the organic phase; d) selectively stripping the element(s) Efrom the organic phase; e) separating the first and second extractants present in said organic phase at the end of step d).

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Bagnols sur Ceze, France

Pascal Baron