Patent ID: 9091486
Filing Date: 2015-07-28
Classification: F22B,F28D,F28F,G21C,G21D,Y02E

Abstract:
1. A pressurized-water-cooled nuclear reactor, comprising a pressurized tank, which houses a core, a hot header over the core, and a cold header surrounding the hot header and separated from the hot header by a separation structure and in which primary water constituting a core cooling fluid circulates; the reactor comprising at least one steam generator, extending along a vertical axis and positioned in the cold header and in which secondary water circulates for removing heat from the primary water; the steam generator comprising a plurality of heat-exchange tubes in which the secondary water circulates and which have respective substantially plane spiral portions set on top of one another in a number of levels to form a substantially annular tube bundle delimiting a substantially cylindrical central zone, which houses a supply duct in which the pressurized primary water coming from the hot header flows downwards; wherein each spiral portion is constituted by a plurality of substantially concentric turns set inside one another about the axis and which lie substantially in a common plane perpendicular to the axis; and wherein each tube comprises a delivery branch that connects a radially external end of the spiral portion to a water-delivery manifold, and a return branch that connects a radially internal end of the portion to a steam-return manifold; and wherein the delivery branches extend in a prevalently vertical direction substantially parallel to the axis, and are set circumferentially alongside one another and are radially external to the annular tube bundles; and the return branches extend in a prevalently vertical direction substantially parallel to the axis, and are set circumferentially alongside one another and radially inside the annular tube bundles; and wherein set within the tube bundle is a substantially cylindrical ferrule provided with first calibrated holes and delimiting inside the supply duct.