Abstract: A nuclear reactor with juxtaposed prismatic fuel assemblies cooled by the flow of a liquid in a cylindrical jacket. A partitioning of the core between the peripheral assemblies and the jacket is constituted by rods parallel to the assemblies, guided laterally by bracing plates fast to the jacket in which the rods are free to slide longitudinally.

Abstract: The invention relates to a method and device for unclogging the top surface of the tube plate of a steam generator comprising, in a cylindrical vessel, a bundle of bent tubes of inverted U-shape and connected to a tube plate. The unclogging is achieved by two water jets under high pressure coming from projection heads and which can be directed towards the tube plate. These two water jets are moved simultaneously and symetrically with respect to the diametric boundary line of two zones in the form of a semi-circle on the tube plate. At the same time the detached sludge is removed by aspiration of this sludge throughout the length of the peripheral zone of the tube plate.

Abstract: A steam generator having cold branch and hot branch zones defined, inside the secondary envelope, by vertical partitions separating the cold limbs from the hot limbs, and outside the secondary envelope by a skirt surrounding a portion of the latter on the cold branch side, forming therewith a space closed on its sides and at its lower portion while leaving a passage to the cold branch zone from the inside of the envelope. The space is open at the top so that recycled water can return to the bundle of U-tubes through both zones, but secondary feed water circulates for the most part in the cold branch zone. Recycled water may be distributed between the cold and hot branch zones, and the pressure in these zones may be balanced at the level of a horizontal, perforated tubular plate.

Abstract: The invention relates to a device for separating water and steam at the outlet of a vaporization vessel of a recycling steam generator. The device constitutes an assembly of vertical cylindrical tubes enclosing the deflector elements enabling the separation of water and steam. These vertical separators or cyclones are grouped in sub-assemblies. Each of the cyclones of a sub-assembly is fixed to the upper portion of a common support structure, comprising from below upwards a tubular column fixed vertically on the upper portion of the vaporization vessel and a structure in the form of an upwardly flared vessel, in communication with the tubular column and with the cyclones fixed at its upper portion. The separation device is thus constructed in modular form. The invention is particularly applicable to steam generators of pressurized water nuclear reactors.