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 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.

Abstract: The invention relates to a process for the separation of at least one element such as Nb, Sb, Ce+Pr, actinides and elements from groups VIIb and VIII of the Periodic Classification of Elements from aqueous solutions resulting from the reprocessing of spent nuclear fuels.This process consists of contacting said aqueous solution with a solid resin based on a vinyl pyridine polymer or copolymer and separating from said solution the resin used for fixing said element or elements.The resin is in particular a poly(vinyl-4-pyridine) powder in crosslinked from and the separated elements are e.g. ruthenium, rhodium, palladium, technetium, manganese, cobalt, iron, nickel, cerium and praseodymium.

Abstract: A mixer-settler is provided which is modulatable and permits use, manipulation and maintenance within a tight, shielded enclosure using a telemanipulator. The mixer-settler is constituted by several modules (M1, M2, M3), which can be reciprocally dismantled by using tight connecting means (19, 20, 21). The inlets and outlets (17, 18) for the heavy and light phases are located on the front face (40) of each module. Regulating members (9, 10, 11) issue onto the upper surface of each module close to the front face (40). Preferably, shield windows (12) make it possible in each case to see the interphase of a stage comprising a mixing chamber (1) and a settling chamber (2). This is completed by a motorization assembly (3) placed above the module. Application to the treatment of radioactive liquids.

Abstract: The invention relates to the use of thioether ligands in accordance with the formula: ##STR1## in which R.sup.1 and R.sup.2, which can be the same or different, represent alkyl radicals, R.sup.3 is an alkyl radical and A represents a divalent radical chosen from among the radicals of formula:--(CH.sub.2).sub.m ----(CH.sub.2).sub.n --X--(CH.sub.2).sub.p -- ##STR2## in which m is equal to 0 or is an integer from 1 to 6, n and p are integers between 1 and 6 and X represents O or S, for recovering the palladium present in a nitric aqueous solution (A.sub.0) for dissolving irradiated nuclear fuel elements.For example, it is possible to use the ligand of formula (I) with A representing CH.sub.2 --S--CH.sub.2 and R.sup.1 and R.sup.2 representing C.sub.10 H.sub.21.

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.