Abstract: A system for removing sludge from a sludge-bearing fluid flowing in a vertically oriented nuclear steam generator so that the sludge is not present therein in sufficient quantities to corrode components (e.g., heat transfer tubes) located in the steam generator. The system comprises a tube sheet having a plurality of apertures therethrough for receiving the ends of the heat transfer tubes so that the tubes are supported by the tube sheet. The tube sheet has a top surface thereon and also a recess formed in the top surface for separating and for collecting the sludge from the sludge-bearing fluid. The recess has a substantially frusto-conical wall generally converging at the bottom end of the recess for providing a settling basin for the sludge after the sludge is separated from the sludge-bearing fluid. A pipe extends from adjacent the bottom end of the recess to the exterior of the heat exchanger for transporting the sludge from the recess to the exterior of the heat exchanger.

Abstract: A sludge trap, or mud drum, for use in nuclear steam generators includes internal baffles defining multiple laminar flow paths having decreased vertical settling distances. The baffling arrangements take advantage of the diverging nature of circular geometry of sludge traps such that flow path cross-sectional areas are maintained and increased in the direction of flow, to avoid undesired, detrimental flow acceleration; turbulence as well is minimized, thereby to achieve a desired quiescent environment for effective gravitational settlement of sediment and particulate matter.

Abstract: An improved steam generator having an auxiliary recirculation path in its secondary side is disclosed herein, as well as an improved method for mixing wet lay-up chemicals therein. The invention is particularly applicable to nuclear steam generators of the type including a secondary shell that contains a quantity of water, a bundle of heat exchange tubes, and a tube wrapper that concentrically surrounds the tube bundle for defining a downcomer path. The auxiliary recirculation path allows the water present within the tube wrapper to circulate through the downcomer path when the water level within the secondary shell is lowered below the upper edge of the tube wrapper during maintenance operations.

Abstract: A mechanical feeding mechanism for delivering plugs seriatum from a cylindrical delivery chute having upper and lower latching mechanisms. Each of the upper and lower latching mechanisms are movable from a latching position wherein the latching mechanism engages a plug in the chute and an unlatching position. Linkage mechanism connects the upper and lower latching mechanisms such that when one of the latching mechanisms is in the unlatching position the other latching mechanism is biased toward the latching position.

Abstract: A sludge trap, or mud drum, for use in nuclear steam generators includes internal baffles defining multiple laminar flow paths having decreased vertical settling distances. The baffling arrangements take advantage of the diverging nature of circular geometry of sludge traps such that flow path cross-sectional areas are maintained and increased in the direction of flow, to avoid undesired, detrimental flow acceleration; turbulence as well is minimized, thereby to achieve a desired quiescent environment for effective gravitational settlement of sediment and particulate matter.

Abstract: A nuclear steam generator having a feedwater ring disposed in the upper portion of the steam generator above the tubes, the feedwater header having a plurality of J-shaped discharge nozzles, some of which are in fluid communication with the upper portion of the feedwater ring header and others being in fluid communication with the lower portion of the feedwater ring header, those in fluid communication with the lower portion of the feedwater ring header having a discharge elevation lower than those in fluid communication with the upper portion of the feedwater header so that during low feedwater flow operation feedwater is fed from the lower portion of the feedwater header removing cold water therefrom and promoting mixing of the feedwater in the header in order to reduce stratification of feedwater therein.