Abstract: The present invention relates generally to the field of compensation methods for nuclear reactors and, in particular to a method for fail-safe reactivity compensation in solution-type nuclear reactors. In one embodiment, the fail-safe reactivity compensation method of the present invention augments other control methods for a nuclear reactor. In still another embodiment, the fail-safe reactivity compensation method of the present invention permits one to control a nuclear reaction in a nuclear reactor through a method that does not rely on moving components into or out of a reactor core, nor does the method of the present invention rely on the constant repositioning of control rods within a nuclear reactor in order to maintain a critical state.

Abstract: A pressure vessel comprises an upper vessel section and a lower vessel section. A nuclear reactor core comprises fissile material contained in a containing structure and disposed in the lower vessel section. Upper internals are disposed in the lower vessel section above the nuclear reactor core. The upper internals include at least guide frames and internal control rod drive mechanisms (CRDMs) with CRDM motors mounted on a suspended support assembly including a plurality of hanger plates connected by tie rods. The plurality of hanger plates includes a lowermost hanger plate having alignment features configured to align the upper internals with the containing structure that contains the nuclear reactor core.

Abstract: A rhenium lined niobium alloy tube for use as a clad tube for nuclear fuel in a nuclear reactor. The tube is produced by an electro deposit process. A graphite mandrel is placed in the electro deposit chamber as the cathode material. Refined rhenium stock is used as the anode material. The chamber is filled with the chloride electrolyte. The chamber is closed and the electrolyte bath is heated. Current and voltage applied across the anode and cathode cause the rhenium to be deposited on the mandrel. Refined niobium alloy is then used as the anode material and applied over the rhenium on the mandrel to a desired thickness. The part is removed from the chamber and ground to the desired outside diameter. The graphite mandrel is removed from the tube.

Abstract: A method for fabricating a cable-in-conduit-conductor for use in superconductor application is described. The system utilizes a work surface with drum means provided at each end. A superconductor cable is fed from a supply source at one end. After the cable is pulled through a tube on the work surface, the leading edge of the cable is bent around one of the drums and returned to the opposite end of the table. This naked length of cable is once again bent around one of the drums and then pulled through another tube on the table. This process is repeated until an acceptable length of superconductor cable is present. Tension means are used in conjunction with a tube mill which compresses the tube-cable combination into a viable cable-in-conduit conductor (CICC). Notably, as this tension-compression is occurring, the naked lengths of cable are eliminated and each separate tube section is joined together to create a uniform CICC.

Abstract: A steam generator system incorporates multiple processes, either in series or independently and with each process having a process fluid associated therewith, to transfer heat between a common working fluid and the process fluids in order to generate steam from the working fluid. The heat transfer may be controlled by controlling the flow of the working fluid to further regulate and control the generation of steam and/or the individual processes themselves. The generator system includes a vessel and may optionally have baffles located within the vessel to separate the flow of working fluid into a recirculation system to facilitate in the overall operation of the system. The working fluid must be capable of forming steam and preferably consists essentially of water. Straight tubes, plate-type heat exchange surfaces having a common boiling fluid stream, U-tubes, helical tubes, and/or curved tubes may be used as heat exchange means for transferring heat between the working fluid and the process fluids.

Abstract: A low resistance splice connects two cable-in-conduit superconductors to each other. Dividing collars for arranging sub-cable units from each conduit are provided, along with clamping collars for mating each sub-cable wire assembly to form mated assemblies. The mated assemblies ideally can be accomplished by way of splicing collar. The mated assemblies are cooled by way of a flow of coolant, preferably helium. A method for implementing such a splicing is also described.

Abstract: A method for reducing or eliminating sagging in plasma arc keyhole welds adds a fluxing agent to the weld. The fluxing agent may be titanium nitride and/or titanium carbonitride. The fluxing agent is added using physical vapor deposition or by painting a slurry onto the weld surface.

Abstract: A modular solar thermal rocket that receives and absorbs solar energy and then acts as a heat exchanger to provide propulsive thrust. Thermal energy storage modules receive and store solar energy via thermal energy storage elements provided in each module. The solar energy is focused into a cavity defined by the modules by a solar energy secondary concentrator. A preheater is positioned adjacent the solar energy secondary concentrator and is in fluid communication with a propellant supply and one end of the thermal energy storage modules. A propulsion nozzle is in fluid communication with the opposite end of the thermal energy storage modules. Stored propellant is directed through the preheater and the thermal energy storage modules where it is heated to a high temperature. The propellant is then directed to the propulsion nozzle where it is exhausted into space to provide propulsive thrust.

Abstract: A thermal solar rocket that includes a solar energy receiver having two sections (a thermal energy storage section and a direct gain section), a solar concentrator, and a propulsion nozzle. In one embodiment, the focus of the solar energy between the storage section and the direct gain section is controlled by mechanical means such as movable insulation. In another embodiment, the focus of the solar energy between the storage section and the direct gain section is controlled by an optical switch in the form of relative motion between the solar concentrator and the solar energy receiver.

Abstract: A solar thermal rocket that includes a thermal energy storage section, a radiant inter-heater, a primary solar concentrator, and a propulsion nozzle. The primary solar concentrator is selectively movable to direct solar energy to either the thermal energy storage section or to the radiant inter-heater. The thermal energy storage section, along with insulation, is arranged to define a cavity such that a focused beam of solar rays can enter the cavity through an aperture in the insulation. The thermal energy storage section typically absorbs and stores solar energy during the non-propulsion portion of the orbital period. The solar rays are captured and absorbed and thereby heat the thermal energy storage section to very high temperatures. A radiant inter-heater directly receives concentrated solar rays and transfers the heat to the propellant during the propulsion phase.

Abstract: An ultrasonic method for determining liquid level in a container employs an electromagnetic acoustic transducer (EMAT) to launch and receive longitudinal ultrasonic waves into a thin metal wall or thin metal foil seal of the container, causing it to vibrate and launch ultrasonic compressional waves into liquid contained therein. The compressional waves travel through the liquid contents and reflect off an interface, returning to the thin metal wall and causing it to vibrate in the presence of the magnetic field produced by the EMAT transducer assembly. This induces a voltage in the eddy current coil of the EMAT transducer assembly, and by measuring a time of flight of the ultrasonic compressional waves through the liquid contents, and by using a preestablished value for a velocity of the ultrasonic compressional waves within the liquid contents, the liquid level of the contents can be determined.

Abstract: A composite insulation of S2 glass fibers and epoxy is formed having a more nearly uniform coefficient of thermal expansion in all three planes for use in cryogenic superconductor applications. The glass fibers have a three-dimensional weave.

Abstract: A self-protected modular high temperature superconducting (HTS) down-lead that is capable of carrying large currents from a room temperature power source to a superconducting device operating at cryogenic temperatures. This down-lead incorporates a safety lead capable of carrying current and absorbing heat to protect the HTS material of the lead in the event of catastrophic failure of the HTS elements. The lead is in continuous contact with the HTS material and provides protection from interrupts and excess current. The down-lead is modular in design, and parts are easily replaced. Further, the down-lead is cooled through conduction in the middle stage, and gas cooled in the upper and lower stages by independent gas sources.