Abstract: The invention relates to an apparatus for survey and/or treatment of a smooth curved surface.The apparatus comprises a vehicle able to be moved on the surface along a predetermined path, the vehicle being provided with abutment means movable with respect to the body of the vehicle. A support arm of the vehicle is fixed to this by a swivel pivot point. The support arm is fixed close to the center of curvature of the curved surface. The axes of the abutment means and of the arm of two supports can be oriented to be substantially concurrent in the vicinity of the center of curvature of the curved surface. Means for survey and/or treatment of the curved surfaces are fixed to the vehicle. Means for control of driving of the vehicle and of the survey and/or treatment means are also provided.Application to the survey and to the maintenance of water boxes of steam generators of electo-nuclear power stations.

Abstract: A gas filter system, suitable for use in a safety installation for nuclear reactor confinement vessels, comprises a generally cylindrical enclosure having a closed bottom. In an upper part of the enclosure is an inlet for the gas to be filtered. There is an outlet for the filtered gas at the side of a lower part of the enclosure. The gas passes at a low speed through a horizontal filter bed of predetermined thickness consisting of a layer of a granular filter medium. The filter medium is supported by a supporting layer of a lightweight granular material which has an average particle size greater than that of the filter medium. This layer extends down to the closed bottom of the enclosure. The filtered gas is recovered and conveyed to the outlet by a plurality of tubular members which have walls through which the gas can pass and which are placed in the supporting layer. These tubular members discharge into an annular manifold on the outside periphery of which is the outlet for the filtered gas.

Abstract: The invention concerns plasma torches comprising an upstream electrode (12), a downstream electrode (11), a chamber (15) for the injection of plasma producing gas, a priming electrode (13) and optionally a magnetic field coil (14), in which the upstream root of the arc is displaced on the upstream electrode. According to the invention, in order to control a continuous or reciprocating and/or an oscillatory translation, the field coil is supplied with a variable direct current, if need be a pulsatory undulatory current, and/or a diffuser is placed at the inner end of the upstream electrode which is supplied with a modulated flow of gas which it causes to whirl. Application in high power plasma torches for regularizing and rendering uniform the wear of the electrodes so as to prolong the life thereof.

Abstract: A safety device for limiting the pressure of a fluid to a predetermined value comprises a preshaped diaphragm having a downstream convex face and an upstream convex face mounted as a closing or sealing device in a pipe. A first knife faces the convex face of the diaphragm at such a distance that a predetermined pressure exerted by the fluid on the concave face of the diaphragm brings the latter into contact with the knife which then causes a bursting of the diaphragm. A second knife is fitted to face the concave face of the diaphragm and a mechanism is provided for making the second knife strike against the diaphragm in order to bring about the tearing thereof when the concave face of the diaphragm is exposed by the fluid to a pressure below said predetermined pressure. The first knife has a passive operating mode, but the second knife has an active operating mode.

Abstract: The core of a pressurized water nuclear reactor is partly formed from dismantlable assemblies (10), whereof the rods contain mixed UO.sub.2 -PuO.sub.2 oxide pellets, said assemblies (10) being subdivided into concentric zones (12,14,16) with a plutonium concentration decreasing from the inside to the outside. At the end of each irradiation cycle, the rods (C.sub.3) located in peripheral zone (16) are discharged and the rods (C.sub.2,C.sub.1) located in the other zones (12,14) are transferred towards the outside of assembly (10) into zone (14,16) adjacent to that which they previously occupied. New rods (C.sub.4) with a single enrichment are then introduced into the thus freed central zone (12).

Abstract: A process for measuring the temperature of a body by optical detection is disclosed wherein the body is heated by a modulated light beam and the radiation coming from the object is detected. The modulated component of the detected signal is measured and the temperature of the body is extracted by signal processing.

Abstract: Electric induction cooking appliance comprising a support for a vessel (C) to be heated and at least one flat inductor intended to be fed by a frequency convertor, characterized in that the inductor consists of a first coil (4) having a first sense and of at least one second coil (5) formed of at least one turn of opposite sense to that of the first coil.

Abstract: The handling pond of a pressurized water nuclear reactor is equipped with orientable lighting apparatuses. Each apparatus comprises a floating lighting means mounted at the end of an also floating articulated arm. The opposite end of the arm is supported by a vertical guide mounted on one edge or side of the pond. The lighting means comprises a floodlight emitting a parallel beam of light through the transparent bottom of a tight box, which also contains means for orienting the floodlight about two orthogonal axes. A cover, positioned out of the water, gives access to the interior of the box.

Abstract: This reservoir is provided with a fluidtight covering of metal sheets (6) welded together by their edges and supported by beams (2) each comprising two section elements (16, 17), and three longitudinal channels. In cross-section, the first and second section elements each have the shape of a U, the second section element being substantially narrower than the first element and being fixed by the edge of its branches (18) to the bottom (19) of the first section element so as to define an inspection channel (20) having a closed cross-section, and two draining channels (21) having an open cross-section. The surface of the bottom of the second section element (17) which faces toward the exterior of the beam, is contained in the same plane as the edges (11) of the branches (22) of the first section element (16) so as to form the bearing surface (14) for two sheets (6) in the region of their weld head (15) which interconnects them.

Abstract: The invention relates to an optical probe comprising an optical means (5) having a given refractive index. This optical means is able to reflect an incident light beam if it is located in a medium (3), whose refractive index is higher than the given index and is able to reflect the incident light beam if it is in a medium (2), whose index is below the given index. The optical refraction or reflection means (5) is a cone of revolution, the axis (X) thereof being parallel to the incident beam (6) and to the optionally reflected beam (11), the base (12) of said cone receiving the incident light beam and is perpendicular to said incident light beam and to the possibly refracted beam. The cone and at least part of the optical fibres transmitting the incident and reflected light beams are located in a tight box or case. Application to the detection of interfaces of different media and to the determination of the components of a two-phase medium.

Abstract: The invention relates to a device for connecting a cylindrical or tubular submersible element to a tubular sleeve, inter alia a submersible heating element to the sleeve of a pressurizer basin, comprising a first flange associated with the sleeve, a second flange associated with the submersible element, a resilient metal joint interposed between the two flanges, two screwthreaded tubular members, one male, the other female, which cooperate with one another via their threads, the threaded male member acting on the first flange via the agency of two half-rings, the female screwthreaded member acting on the second flange, the screwing of the two screwthreaded tubular members causing the compression of the joint.

Abstract: The invention relates to a process for the decarbonation of minerals, in powdered form, in a fluidized bed. For example, the process applies to the production of quick lime and/or magnesia from lime stone and/or dolomite fines which are not rendered sufficiently valuable at present.The process comprises recycling a portion at least of the carbon dioxide produced to be used as sole fluidizing gas, the fluidized bed being heated to the desired decarbonation temperature by direct heat supply within the fluidized bed by means of electric devices.Production of decarbonated minerals and of CO.sub.2.

Abstract: The invention relates to a device for sealing an opening (7) defined by an edge (6), comprising a sealing element (2, 102), the dimensions of which are at least equal to those of the opening (7), means for securing the said sealing element opposite the opening, and means for ensuring fluid-tightness between the sealing element (2, 102) and the edge (6). The means for ensuring tightness between the sealing element (2, 102) and the edge (6) consists of a flexible membrane (8), means for fixing the circumference of this membrane to the sealing element (2, 102) so as to define a volume (16) between the membrane (8) and the sealing element (2, 102), and a communication hole (18, 32) provided in the sealing element so as to connect the volume (16) to a source of pressurized fluid.

Abstract: A fast neutron nuclear reactor having a vessel filled with liquid metal and sealed in its upper part by a box slab having a central opening in which is placed a plug-cover-core overhanging the core of the reactor. The central opening is surmounted by a cell containing the handling and storage mechanism for the plug-cover-core and a mechanism for handling the assemblies. The latter can be moved on annular rails and can be collapsed against the wall of the cell, in order to permit the manipulation of the plug-cover-core. A radial passage connects the cell to a transfer station.

Abstract: Process for the elimination of corrosion products formed on the tube plate and in the gaps between the tubes and the spacer plates of a steam generator of a pressurized water nuclear reactor, in order to prevent the appearance of a corrosion phenomena, which can lead to necking or denting of tubes by oxide growth.The process consists of reacting with said oxides at between 50.degree. and 100.degree. C., an aqueous solution containing 6 to 8% gluconic acid, 3 to 5% citric acid, approximately 0.5% of a corrosion inhibitor and ammonia until a pH between approximately 3 and 9.5 is obtained.

Abstract: A steam generator feed water heater comprises a pressurized enclosure inside which is a heat exchanger through which the feed water is caused to flow. There is at least one horizontal condensate inlet tube, as well as at least one condensate outlet tube at a low point on the enclosure. A double screen device associated with the condensate inlet tube comprises an inner screen with a cylindrical side wall and, surrounding this inner screen, an outer screen having one end linked to the inner screen. A bottom wall common to both screens constitutes an impact wall facing the inner screen. Passage areas are provided by perforations in the screens not facing each other over most of the perimeter of their transverse cross-sections.

Abstract: Apparatus for the release and recovery of living organisms collected or trapped on the rotary filters of water pumping stations.The apparatus comprises:on the inside of the filters, a system of two rows of multiple washing jets using water under low pressure, whose nozzles are directed towards the filter panels, so that the jets of the two rows meet one another and cooperate to form a single liquid stream;deflectors arranged at radial intervals on the outer face of the filter panels;on the outside of the filters, a channel shaped like a trough for receiving the washing water and recovering the living organisms, whose opening is oriented towards the said rows of washing jets, the edge of the opening being rounded or rotary in its lower part.

Abstract: A fire grate is adapted to support a combustible mass. It is inclined longitudinally from a feed end at which it receives the combustible mass to a discharge end. It comprises a plurality of elements disposed in transverse rows alternately fixed and mobile. Each element is rectangular in plan and has a top side and a bottom side, openings by means of which the top side and the bottom side communicate, and a generally transversely oriented front protuberance on the top side in the vicinity of its transverse edge at the feed end. All the openings are in a dorsal surface of the front protuberance facing the discharge end.

Abstract: An automatic rain gauge or pluviometer comprising a first receiver for receiving dry fallout; a second receiver for receiving wet fallout, provided with a first sensor able to emit a signal when a certain wet fallout sample volume has been collected; a closing device permitting the alternating closure of the two receivers as a function of a signal emitted by a precipitation detector; a measuring device located at the outlet of the second receiver and used for carrying out measurements of physicochemical quantities on the sample; a sampling device located at an outlet of the measuring device and used for arranging and keeping at a temperature below 0.degree. C. a fraction of each sample collected; and a checking system used for automatically controlling the aforementioned components as a function of the signals emitted by the sensors, including the first sensor and the precipitation detector and for managing the measurements performed on the sample.

Abstract: The invention relates to an apparatus for handling nuclear fuel assemblies, as well as to an assembly for use with such an apparatus.The apparatus comprises a vertically axed guide tube in which is displaced a grapnel, suspended on a flexible connection such as a chain, under the action of a reduction gear. As the grapnel is immobilized in rotation in the guide tube, an assembly is gripped by means of a bayonet system by controlling the rotation of the guide tube-grapnel assembly by a reduction gear. The apparatus can in particular be suspended on the small and/or large rotary plug of a fast neutron nuclear reactor. It can also be used in a handling hod under gas.