Steam generator with opening(s) in its tube plate for removing debris - from secondary water space above and connected to outside of pressure vessel by passage(s) within plate thickness

摘要

A steam generator comprises an upright cylindrical vessel divided near its lower end by a horizontal tube plate (12) from which inverted U-tubes (24) extend upwards, the upper surface of plate (12) having therein at least one drain opening (46) to enable debris to be flushed from said surface. Tubes (24) carry primary coolant from a nuclear reactor between inlet and outlet chambers beneath plate (12). A passage (44) extends radially within the thickness of plate (12), avoiding the holes which accommodate the ends of tubes (24) to connect one or more openings (46) with a pump (48) outside the vessel. Alternatively a number of passages (44) connected to different openings facilitates more effective flushing. USE/ADVANTAGE - Removing mud and other debris from the secondary water side of the steam generator. Removing potentially corrosive mud from around the lower ends of tubes (24) prolongs their life and that of the steam generator. The location of openings (46) and passages (44) within plate (12) avoids crowding the secondary water space above the plate with extra components which would interfere with inspection and repair.