Commissariat a L'energie Atomique

Michel Germain

Andre Bathellier

Claude Musikas

Andre Chesne

Jean-Yves Pasquiou

Dominique Pareau

Jean-Luc Denis

Bruno Gillet

Christian Lecointre

Sylvie Chevalier

Roger Dewulf

The invention relates to a process for the reextraction in aqueous solution of the plutonium present in an organic solvent, more particularly usable for uranium-plutonium separation. According to this process the organic solvent is contacted with an acid aqueous solution of uranous salt, e.g. uranous nitrate, and hydroxylamine salt, e.g. hydroxylamine nitrate. Under these conditions, the uranous nitrate acts as a reducing agent for plutonium at valency (III and the hydroxylamine nitrate, which is also a plutonium reducing, agent, stabilizes Pu(III) and U(IV) in aqueous phase. Performances comparable to those of the U(IV)-hydrazone nitrate system are obtained without forming prejudicial hydrazine nitrate decomposition products. (FIG. 2).

Process for the reextraction in aqueous solution of the plutonium

The invention relates to the recovery of acid organophosphorus compounds and/or organophosphate ions present in an aqueous solution. According to the invention, the aqueous solution is contacted with at least one organic amino compound which is not very soluble in water, chosen from among compounds having at least one amine function, the salts of these amino compounds and the quaternary ammonium salts and the complex formed is separated from the aqueous solution by reacting these acid organophosphorus compounds and/or organophosphate ions with the organic amino compound or compounds. The amino compound can be a trialkylamine, e.g. triisooctyl amine and contacting and separation can be performed in a co-current or counter-current liquid-liquid extraction installation.

Process for the recovery of acid organophosphorus compounds and/or

Process for the separation of americium from curium contained in an aqueous nitric solution, wherein the initial solution undergoes oxidation at ambient temperature in the presence of phosphoric acid or phosphate ions at a concentration at the most equal to 0.1 mol per liter in such a way as to pass the americium at valency VI, the thus treated solution is brought into contact with a slightly reducing organic solvent having a high affinity for americium at valency VI in such a way as to extract the americium in the organic phase, the organic phase containing the americium at valency VI is then washed, followed by the re-extraction of the americium in the organic phase by means of an aqueous solution.

Process for the separation of americium from curium contained in an

An apparatus for raising a liquid to a given temperature and for controlling and regulating this temperature has a vertical cylindrical enclosure, a vertical tube housing a heating resistor, and a first and a second ferrule located in this order between the tube and the enclosure to define a first, a second and a third annular space. The first ferrule is connected to the lower wall of the enclosure. The tube and the second ferrule are connected to the upper wall of the enclosure. The liquid is supplied to the lower portion of the first space and extracted from the upper portion of the third space. The length of the resistor is shorter by at least one quarter of the height of the tube and orifices in the lower portion of the first ferrule produce a thermosiphon effect between the first and second annular spaces.

Apparatus for raising a liquid to a given temperature

A nitric acid solution having a nitric acid concentration within the range of 0.01 to 15 M and containing plutonium(IV) ions and/or plutonium(III) ions is reacted with a formic acid solution in order to obtain a precipitate of plutonium(III) formiate.

Method of preparation of trivalent plutonium formiate

The method of selective stripping from plutonium-loaded organic solvents which may also contain uranium consists in passing the organic solvent in countercurrent contact with an aqueous solution of a salt of hydroxylamine and formic acid, the concentration of formic acid in the reaction medium being within the range of 1M to 5M. The method finds an application in the stripping of plutonium from trilaurylamine diluted in an aromatic hydrocarbon such as tert-butyl benzene or in the separation of uranium and plutonium contained in tributylphosphate diluted in an aliphatic hydrocarbon such as dodecane.

Method of selective stripping of plutonium from organic solvents loaded

An anion exchange is carried out between an aqueous solution of a hydroxylamine salt and an organic solution of a formiate of an amine which is insoluble in water in accordance with the reaction:

Growing community of inventors

Marcoussis, France

Michel Germain