Commissariat a L'energie Atomique

Gilles Aubert

Didier Costes

Maurice Moulin

Gilles Barras

Andre Maury

Erik Tomachevsky

Roger Lemoine

Guy Petit

A device for the detachable fixing of an internal structure to a circular wall of a pipe or container. The device comprises one or more deformable annular members having blocks regularly distributed over its periphery. The application of radial forces between the blocks reduces the diameter level therewith and makes it possible to fit and remove the device. Application more particularly to the fixing of internal structures in the primary circuit of pressurized water reactors.

Device for removably fixing an internal structure to a circular wall

The present invention relates to a nuclear boiler comprising a vessel whose top is closed by a dismountable cover, a cage bearing the core of the reactor and separating the vessel into an inner hot zone and an outer cold zone, at least one steam generator disposed outside the vessel and comprising a tight enclosure, a tube plate, separating the enclosure into a primary part, or water box, and a secondary part, and bearing U-shaped tubes whose ends open into two concentric zones of the water box separated by an internal structure, at least one hot connecting pipe and one cold connecting pipe respectively connecting the hot zone and the cold zone of the vessel to each of the concentric zones of the water box, wherein the tube plate, the tubes and the secondary part of the enclosure of the steam generator define a sub-assembly dismountable from the primary part of the enclosure, the hot connecting pipe being dismountably mounted between the cage and the internal structure of the water box, this strucutre itself being dismountably mounted in the primary part of the enclosure.

Nuclear boiler with dismountable water box

Refuelling of a nuclear reactor and especially a PWR is carried out in the steps which consist in removing and storing the reactor closure head, in moving the control rods from a bottom position to the top position and securing the rods to the upper internal structure, in removing and storing the assembly constituted by the upper internal structure and the control rods, in replacing the spent fuel and in re-positioning the upper internal structure and the closure head.

Method for refuelling a nuclear reactor and device for carrying out said

A device for guiding control rods of the absorber-pin cluster type and placed above the reactor core comprises a rigid top plate applied against the reactor vessel and provided with openings joined to long vertical tubes in which the control rod assembly is slidably mounted, an intermediate plate below coolant outlets for the sliding displacement of each absorber pin through corresponding apertures in said plate, and short connecting tubes which preferably provide a mechanical connection between the intermediate plate and a bottom plate and serve to guide the absorber pins, or alternatively short connecting tubes which guide the absorber pins and support members rigidly connected between the plates.

Nuclear reactor

Two cylindrical shells having different diameters and covered with a metallic heat-insulation are disposed respectively within the lower and upper portions of a pressure vessel, the upper shell being closed by a lid. A chamber filled with fluid in liquid phase up to the liquid-vapor interface and with gas above said level is formed by the shells between the vaporizable fluid and the internal vessel wall, a cold liquid seal being formed by the overlapping portion of the shells. Radial expansion of the shells is permitted by supporting means at the level of at least three through-passages and is absorbed by leak-tight means placed opposite to the through-passages.

Device for thermal insulation of a prestressed concrete vessel which

Closure elements uniformly spaced at the periphery of a concrete plug are each applied at one end against the top face of the plug and at the other end against the corbel of a prestressed concrete pressure vessel. Each closure element is constituted by a hydraulic jack whose closed extremity is coupled to a first articulated bearing shoe. Adjustable mechanical means within the jack body maintain this latter in contact with an annular shoulder of the jack piston in all relative positions, the emergent extremity of the piston being coupled to a second articulated bearing shoe.

Device for closing a pressure vessel

The invention relates to a device for inspecting at a distance walls which are difficult of access such as metal walls forming a nuclear reactor vessel. The device comprises a detector secured to a slide movable along guide rails attached to a frame. Probes bearing on the metal walls are secured to a plate on the frame, each probe transmitting a signal proportional to the distance between the guide rails and the place where the probe bears on the part of the wall to be checked. The device includes two motors secured to a second frame and which are controlled by electrical signals from the probes. Each motor actuates a pinion engaging the racks secured by pivots to the first frame and the two ends of the guide rails. A potentiometric monitoring device stops the motors when the signals proportional to the distance between the wall and guide rails as measured by the probes are equal to one another and to a controlled value. The detector preferably comprises an assembly of transducers and ultrasonic receivers.

Growing community of inventors

Orsay, France

Gilles Aubert