Abstract: A nuclear reactor including: a vessel including at least two parts; a reactor core placed in the vessel and containing fuel rod assemblies; at least one internal structure located within the vessel and having a flange portion sandwiched between the two parts of the vessel; an insertion unit for inserting a neutron-absorbing liquid in the fuel rod assemblies, placed in the vessel; and external control devices placed outside the vessel and connected to the insertion unit through conduits placed inside the internal structure, including the flange portion, wherein the insertion unit comprises a transmission unit partly placed in the conduits.

Abstract: Device for pressure drop, and/or closing and sealing a fluid circuit, with internal cartridge and mobile tube. The inventive device serves to produce a variable singular pressure drop on a line but also serves, optionally, to close and seal this line which may have a large diameter, at high pressure and at high temperature. In fact, via the movement of a mobile tube, the device of the invention serves to variably shut openings for the passage of the fluid transported in the line, this mobile tube may optionally create an autoclave seal on a closure seat at the end of travel. The torque required for operating the device is very low throughout the travel. Assembly and maintenance are simplified by the use of a removable cartridge immersed in the fluid containing almost all the members required for operating the device. It operates on all types of fluids.

Abstract: Installations for mounting, controlling, and guiding control rods in and outside a vessel may be removed and passage through an upper internal part may thereby be avoided. An upper internal part is placed near the core of a reactor and laterally emerges on the outside of the vessel. All the transmission, control, and fluid systems pass through this internal part and emerge, by a mobile connection part, for each cluster of control rods, on an assembly head containing tanks of liquid neutron absorber, and injection circuits in injection channels placed between the fuel rods.

Abstract: A device comprising a bundle of channels (8, 23), tubes or similar units permanently is arranged in the reacotr and designed to contain a neutrophage fluid that absorbs neutrons. In addition, this device comprises means that allow one to vary the number of absorbing channels (8, 23) as a function of the desired modulation.

Abstract: A device comprising a bundle of channels (8, 23), tubes or similar units permanently is arranged in the reactor and designed to contain a neutrophage fluid that absorbs neutrons.

Abstract: The method and device are able to overcome possible clogging of measuring devices comprising probes each surrounded by a tranquilliser. It chiefly comprises a tranquilliser (21), preferably spherical in shape, fitted with a separating partition (33) allowing measurement via side holes (32) in a measuring channel (20) and return of condensates via end holes (35) leading to a deflector for evacuation via slatted openings (23) leading into the steam generator (1). Outer measuring holes are made in the median plane of the tranquilliser (21). Application to all steam generators.