Abstract: A method of operating a vapor generating system, including a once-through vapor generator, wherein wet vapor is generated in the upper portion of the load range and superheated vapor is generated in the lower portion of the load range is disclosed. Generated vapor is passed through an external and remote moisture separator. Superheated vapor is desuperheated by liquid injection as it passes from the vapor generator to the moisture separator.

Abstract: A blowdown apparatus for effectuating the removal of contaminants entrained within the boiler water of a vapor generator. The apparatus comprising a perforated blowdown pipe vertically oriented within the generator. In addition, a blowdown and drain connection is provided near the lower end of the pipe so that contaminant bearing blowdown fluid may be expelled from the generator.

Abstract: A vapor generating unit having a U-shaped tube bundle is provided with an orificed downcomer shroud and a fluid flow distribution plate between the lower hot and cold leg regions to promote fluid entrained sediment deposition in proximity to an apertured blowdown pipe.

Abstract: A typical embodiment of an integral pressurized water nuclear reactor and straight-tube steam generator combination in accordance with the invention includes a generally cylindrical pressure vessel that is assembled from three segments which are bolted together at transverse joints to form a fluid and pressure tight unit that encloses the steam generator and the reactor. This novel construction permits primary to secondary coolant heat exchange and improved control rod drive mechanisms which can be exposed for full service access during reactor core refueling, maintenance and inspection.

Abstract: The tubes of a heat exchanger tube bank have a portion thereof formed in the shape of a helix, of effective radius equal to the tube radius and the space between two adjacent tubes, to tangentially contact the straight sections of the tubes immediately adjacent thereto and thereby provide support, maintain the spacing and account for differential thermal expansion thereof.