Abstract:
The invention relates to a process for separating, in an aqueous medium, at least one actinide element from one or more lanthanide elements by using at least one molecule which sequesters the said actinide element to be separated and membrane filtration, the said process successively comprising: a) a step of bringing at least one molecule which sequesters the said actinide element in contact with the aqueous medium, the said molecule not being retained in the non-complexed state by the said membrane and being capable of forming a complex with the actinide element to be separated, comprising the said element and at least two of the said sequestering molecules, which complex is capable of being retained by the membrane; b) a step of passing the aqueous medium over the membrane in order to form a permeate on one side, comprising an aqueous effluent depleted of the said actinide element, and a retentate comprising the said complex.
Abstract:
The invention concerns the recovery of Pu (IV) by using crown compounds.According to the invention, the aqueous solution containing the plutonium (IV) is placed in contact with at least one crown compound, for example DCH 18C6, dissolved in an organic diluting agent, such as benzonitrile. In the case where the solution only contains traces of Pu, it is possible to use a crown compound secured to a solid phase, such as silica.The aqueous solution is a concentrated solution of fission products, an effluent originating from an irradiated nuclear fuel reprocessing installation or a concentrated solution of plutonium with americium.
Abstract:
The invention relates to a process for separating sodium from aqueous effluents resulting from the reprocessing of spent nuclear fuel elements. According to the invention, the effluent (3) is introduced into a tangential filtration module (11), whose membranes are made from polyaramide, sulphonated polysulphone or perfluorinated ionomer, so as to collect a permeate P containing sodium, depleted in radioactive elements and a retentate R enriched in radioactive elements.
Abstract:
The invention concerns the recovery of Pu (IV) by using crown compounds.According to the invention, the aqueous solution containing the plutonium (IV) is placed in contact with at least one crown compound, for example DCH 18C6, dissolved in an organic diluting agent, such as benzonitrile. In the case where the solution only contains traces of Pu, it is possible to use a crown compound secured to a solid phase, such as silica.The aqueous solution is a concentrated solution of fission products, an effluent originating from an irradiated nuclear fuel reprocessing installation or a concentrated solution of plutonium with americium.
Abstract:
The invention relates to a process for separating, in an aqueous medium, at least one actinide element from one or more lanthanide elements by using at least one molecule which sequesters the said actinide element to be separated and membrane filtration, the said process successively comprising: a) a step of bringing at least one molecule which sequesters the said actinide element in contact with the aqueous medium, the said molecule not being retained in the non-complexed state by the said membrane and being capable of forming a complex with the actinide element to be separated, comprising the said element and at least two of the said sequestering molecules, which complex is capable of being retained by the membrane; b) a step of passing the aqueous medium over the membrane in order to form a permeate on one side, comprising an aqueous effluent depleted of the said actinide element, and a retentate comprising the said complex.
Abstract:
A process in which isotopes of the same element belonging to the alkaline earth metals, transition elements and heavy metals having an atomic mass of less than 209, in particular lanthanide metals, are separated in an aqueous medium by treating an aqueous medium.
Abstract:
Process for separating plutonium from uranium contained in a nitric acid aqueous solution from the reprocessing of irradiated fuels comprising plutonium, uranium and fission products by means of crown ethers. Nitric acid aqueous solution (5) containing plutonium, uranium and fission products is contacted at (2) with an organic liquid membrane (3) containing a crown ether. The uranium and plutonium are extracted in the liquid membrane (3) and then transferred by said membrane into a receiving solution (7), which becomes enriched with uranium, because the latter is transferred more rapidly than the plutonium. The crown ether can be DCH 18 C6 or DB 18 C6.
Abstract:
A process in which isotopes of the same element belonging to the alkaline earth metals, transition elements and heavy metals having an atomic mass of less than 209, in particular lanthanide metals, are separated in an aqueous medium by treating an aqueous medium.
Abstract:
The invention relates to the separation of lanthanides and actinides by nanofiltration complexation. The object of the invention is to satisfy the existing need for a simple, efficient and economical technique for separating lanthanides and actinides. This object is achieved by a process consisting of using ligands of the polyamino acid type, such as EDTA or DTPA, for complexing lanthanides and/or actinides before separating them by nanofiltration. The invention further relates to novel polyamino acid ligands incorporating ligand structures additional to EDTA and DTPA. Application to the production of rare earths or nuclear waste processing, especially to recycling operations carried out on spent nuclear fuels is also discussed.
Abstract:
The invention relates to a process fop trapping gaseous ruthenium on polyvinyl pyridine, more particularly usable for recovering radioactive ruthenium from irradiated nuclear fuels.This process consists of contacting a gas containing ruthenium in gaseous form with an adsorbent (11b) constituted by a vinyl pyridine polymer or copolymer for fixing the ruthenium to the latter. The gas can be constituted by yapours from a concentrate of fission products containing ruthenium, which has been heated (at 31) in the presence of an oxidizing agent for volatilizing the ruthenium.