Abstract: Heat recovery steam generators (HRSGs) including components and systems for reducing thermal stress experienced by manifolds within the HRSGs are disclosed. The HRSG may include a manifold receiving a working fluid of the HRSG, a plurality of piping links in fluid communication with the manifold, and an enclosure surrounding the manifold and the plurality of piping links. The HRSG may also include at least one thermal element positioned within the enclosure. The thermal element(s) may surround the manifold. Additionally, or alternatively, the HRSG may include a supplemental heating system in fluid communication with an interior of the enclosure. The supplemental heating system may include a heater for heating fluid (e.g., air), and an inlet conduit in fluid communication with and positioned downstream of the heater. The inlet conduit may be formed through the enclosure to provide the heated fluid to the interior of the enclosure.

Abstract: A pressurized water reactor vessel having a flow skirt formed from a perforated cylinder structure supported in the lower reactor vessel head at the outlet of the downcomer annulus, that channels the coolant flow through flow holes in the wall of the cylinder structure. The flow skirt is supported at a plurality of circumferentially spaced locations on the lower reactor vessel head that are not equally spaced or vertically aligned with the core barrel attachment points, and the flow skirt employs a unique arrangement of hole patterns that assure a substantially balanced pressure and flow of the coolant over the entire underside of the lower core support plate.

Abstract: A ceramic composition for absorbing electromagnetic waves and a method for manufacturing the same are disclosed. The composition comprises a raw powder comprising by weight between about 60% and about 80% Fe.sub.2 O.sub.3, between about 3% and about 8% NiO, between about 15% and about 25% ZnO, and between about 3% and about 8% CuO, and a mixture around the raw powder comprising by weight between about 30% and about 50% water, between about 0.2% and about 0.6% a dispersing agent, between about 0.5% and about 1.0% a plasticizer, and between about 0.1% and about 0.4% a lubricant. The method comprises the steps of grinding the powder, converting the grounded powder into granulates, forming the granulates into a shaped body, sintering the shaped body in a furnace, and cooling the sintered body gradually. The ceramic composition can absorb much of the electromagnetic waves generated from electric devices such as cellular phones, beepers, computers, wireless telephones, etc.

Abstract: A nuclear propulsion reactor. A reactor vessel is provided with an annular first core and a cylindrical second core that is radially encompassed by the first core. Nuclear fuel elements in the first core provide first stage heating of propellant as they direct the propellant axially through the first core. The second core, which contains fissionable material in a highly refractory form, is in fluid communication with the first core for receiving the heated propellant. Fission reactions in the second core driven by leakage neutrons from the first core provide second stage heating of the propellant as it passes therethrough. The second core directs the coolant to a propellant nozzle for providing propulsive thrust.

Abstract: A pressurized water nuclear reactor of the type with vertical control rods passing through the core surrounded by control rod guide tubes. A major portion of the water flow is passed directly to the bottom of the core for upward flow therethrough. A minor portion pressurizes a volume at the top of the vessel and passes downwardly through the control rod guide tubes to join the major portion of flow at the lower end of the core.

Abstract: A bimodal propulsion and power nuclear reactor with coaxial power and propulsion cores, each with its own primary propellant/coolant. An inner core region provides electrical power while an outer annular core region surrounding the inner core region has, passageways for heating a gaseous propellant.