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 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: Process for carrying out an inspection or monitoring round of a nuclear site (5) consisting of recording in a central computer (22) connected to a radiofrequency transmitter/receiver or transceiver (24) a combination or sequence of different collection or reading points (12) grouping sensors (10) constituting the round to be performed. This sequence is copied again into a memory of a portable microcomputer (26) carried by the watchman during the round and connected to a radiofrequency transceiver (28). Each connection point (12) is validated and this validation is transmitted to the central computer (22). The sensors are checked and any abnormal condition is indicated to the central computer (22). All the checks carried out are recorded in the portable microcomputer (26) and copied again at the end of the round into a central computer (22) in such a way that they can be processed.

Abstract: For taking liquid samples, such as active solutions in an irradiated nuclear fuel processing plant within a confined area (10) located below a protective slab (12), use is made of vacuum pots (44), which are pneumatically transferred into a vessel (14) located beneath the slab and which are engaged on needles (40) supplied with fluid to be sampled and projecting into the bottom of the vessel. A pot (44) is moved pneumatically into a nacelle, pod or basket (76) of a rotary drum (72) by means of a transfer duct (60), which passes through a slab element (62) installed in a rotary plug (20). The positioning of the pot vertically with respect to a needle (40) is ensured by the combined rotations of the drum (72) and the plug (20). A vertical displacement of the slab element (62) ensures the sampling before the filled pot is pneumatically evacuated by the reverse path.

Abstract: The invention relates to a glove holder unit for a confinement enclosure.The aim of the invention is to produce a unit making it possible to easily change a protective glove for the hand.This aim is achieved with the aid of a glove holder unit having a sleeve (11), for protecting the arm and the forearm, assembled to a working glove (15), protecting the hand, and placed in an enclosure. The glove holder unit comprises means (49) for locking an assembly means (17) of the glove (15) and the protective sleeve (11). The locking means (49) being mobile between a locked position, in which they maintain the assembly means (17) and the glove (15) outside the enclosure (1) and an unlocked position in which they allow the passage of the glove (15) and its assembly means (17) between the interior and the exterior of the enclosure.

Abstract: In an installation designed for pneumatically transferring pots (12) between a sampling unit, in which these pots are filled with a radioactive liquid sample and an analysis chain or line protected by an enclosure, with the receptacle (36) by which the pots enter the chain or line, is associated a force transducer (42). In conjunction with an electronic measuring means located outside the said enclosure, said transducer weighs the pots and makes it possible to detect when one of them is empty or inadequately filled. An ejection nozzle (66) connected to a compressed air source discharges the pot when it is weighed.

Abstract: A process and apparatus for the transfer out of a tight enclosure of a fluid solution contained in a polluted container (R1). The transfer is accomplished without removing the polluted container from the enclosure and without breaking the seal of the polluted container. After a clean container (R2) is placed in a receptacle (30) normally isolated from the remainder of the enclosure, the solution is transferred into the clean container (R2) vacuum by a needle. Transfer of the clean container out of the enclosure takes place pneumatically following rotation of a casing containing the receptacle.

Abstract: A process for dismantling equipment that is buried, unsheltered, at risk of contamination and possibly is irradiating, and a vessel for implementing this process. According to the invention, buried equipment at risk of contamination, for example, an off-line effluent pipe, is dismantled in sections under cover of a movable vessel (124) placed above the section to be dismantled (12, 14). The invention also concerns a vessel (124) that has a self-supporting structure built around a deck (126) equipped with an elongated central opening (148) giving access to the section to be dismantled (12, 14).

Abstract: Apparatus for measuring the .alpha. activity of a solution and used for determining the plutonium concentration of a solution sampled from an irradiated nuclear fuel reprocessing installation and which comprises a rotary drum (20), which samples a film of solution in a vessel (20), in order to place it in front of a measuring probe (22). Between the probe (22) and the drum (20) is positioned a sealing disk (40) having three positions, which has an effective measuring region (48), a measuring chain quality checking region and a blank measuring region. In order to avoid a solution deposit by condensation on the disk (40) or on the end of the probe (22), a protective gas injection system (49) having passages traversing the vessel cover (16), scavenges the upper face of the sealing disk at three locations corresponding to the three active regions of the latter. A substantially uniform distribution of the gas flow between said three locations is ensured. The protective gas is then sucked in by a tube (122).

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: In order to automatically carry out the emptying and rinsing of non-recoverable bottles or flasks (78) made from a perforatable material such as polyethylene and e.g. containing a low activity solution (88), an apparatus is proposed making it possible to pass the inverted bottles under a double-walled needle (44). The needle (44), operated by a jack, perforates the bottom (82) of the flask (78). Compressed air is then injected into the bottle above the solution (88) through the annular passage formed between the walls of the needle (44), so as to discharge the solution through the central passage of the needle. The flask is then rinsed by injecting pressurized water in place of the compressed air. Finally, the rinsing water is discharged by a further compressed air injection. The emptied and rinsed flasks are then passed to a station, where they are directly discharged into a storage drum.

Abstract: So as to unclog a pipe (16) carrying dangerous and accessible substrances after the removal of a movable member (24, 26), this member is replaced by a guiding member (42), a hydraulic shuttle (66) then being introduced into this guiding member, this shuttle being connected to a high pressure hydraulic source (70) through a box (56) equipped with means for washing the shuttle at the time the latter is withdrawn and means for recovering effluent. The shuttle is then conditioned in a winder connected directly on the box (56).

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: A cardiac valve comprises a ring, one or more flaps, the pivoting axis of the latter including two balls partly extending into a ring cavity and a conical flap cavity. This arrangement improves the life of the valve by reducing wear, stresses, friction and facilitates the assembly thereof if the ring is constituted by two concentric members and if the ring cavity extends on either side of the inner member. The invention more particularly applies to artificial valves installed in the heart in place of defective natural valves.

Abstract: So as to be able to carry out various operations, especially for cleaning observation and simple interventions, on an installation placed in an active cell, the present invention provides a mobile intervention chamber including a caisson (40) adapted to be docked on an access orifice formed in an upper horizontal partition of the cell. The caisson (40) contains the modular elements (88) of an intervention pole (94), these elements being placed on a tool holder barrel (78). With the aid of auxiliary handling arms and a retractable support (110), a pole (94) of a suitable type and length is long-distance constructed on a mechanism (128) mounted on a rotary plate (120) integrated in the ceiling of the caisson (40). Shielding windows (232, 236) and lighting and display systems facilitate the carrying out of intervention operations.

Abstract: A high pressure cleaner comprises a cleaning device (10) and an effluent recovery device (12). The cleaning device (10) is mainly constituted by a cleaning head (20) having a central chamber (44) into which a nozzle (26) sprays a high pressure cleaning liquid, the effluents being recovered in a peripheral chamber (46) connected to a decanter (54) of the recovery device (12). The actual decanter (54) is connected to an exhauster (72) across a liquid-gas separator (60) and filters (70). The liquid phase of the effluents is periodically recovered by a tube (80) immersed in the decanter (54) and connected to a hydroejector (82). The solid phase of the effluents is held back by a filter (92) surrounding the tube (80).

Abstract: Prior to the transportation to a discharge site of a casket or flask in which has been placed a container filled with radioactive waste, through a hole formed in the flask is introduced a probe holder (32) connected by electrical connectors (76,80) to an external measuring apparatus. The probe holder (31) is provided with a handle (68) making it possible, through a mechanism (66,56,54,50), to swing a door (42) to which a probe (34) is fixed between a retracted introduction position and a measuring position in which the probe can be oriented at 90.degree. relative to the probe holder axis. After the probe holder has been coupled by a nut (40) to a container carrier in which is located the container containing the waste, a precise, reproducible measurement of the dose rate within the transportation flask can be carried out.

Abstract: In order to ensure a good seal and a good resistance to shocks and corrosion, without increasing their cost, radioactive waste storage containers are completely made from metal fiber-reinforced concrete. This material is used for producing by molding a drum (210) and a cover (212), as well as a keying joint (224) by which the cover is fixed to the drum. At least one dovetail keying groove is formed in the junction zone between the drum and the cover. Advantageously, a filling material of the same nature as that in which is formed the container is injected into the latter, so as to form a homogeneous block.

Abstract: For clearing or unblocking a pipe (10) filled with a liquid (12) and in which a plug (14) has formed, an apparatus (16) is connected to said pipe. This apparatus applies to the liquid harmonic-rich longitudinal pressure waves and which are preferably constituted by a pulse train. By means of a regulatable compliance volume (28), the harmonic n of the resonant frequency of the incompressible mode of the liquid (12)-pipe (10) system is adjusted, so that its frequency is equal to that of harmonic 1 of the resonant frequency of the compressible mode of the system (n preferably being equal to 1, 2 or 3). This makes it possible to take advantage of the resonances of the compressible and incompressible modes of the system by using a low exciting frequency (below 20 Hz), which reduces the risks of the pipe (10) fracturing or bursting.

Abstract: For passing stepwise bottles (F, F') in front of different stations, in order to more particularly take liquid samples, the bottles are placed in receptacles formed on a plate (24). The rotation of the plate is ensured by a lifting support action using compressed air delivered by injectors (18). Immediate rotation stoppage is obtained when a hole (38) formed in plate (24) faces the end of an optical fiber, whereof the opposite end issues onto an optical detector. Associated with an automatic sampling and dilution system, the assembly can be advantageously installed in a glove box or shielded enclosure in the nuclear industry.