Abstract: The fuel-air mixture preparation system of an internal combustion engine is engaged by signals from a plurality of oxygen sensors located in the exhaust system of the engine. More than one sensor is provided to improve the quality of the output signals in unfavorable engine operation. The individual sensors are provided with comparators which make a comparison between the sensor output and a set-point signal. The output signals from the comparators are fed to a logically controlled coupling circuit which presents them in cyclic alternation to an integrating control circuit which provides a control signal to the final control element in the fuel mixture preparation system for changing the fuel-air ratio. The coupling circuit may also provide a signal based on the logical states of the individual sensor signals.

Abstract: In a system, such as a water-cooled nuclear reactor, water level sensors provide signals to a control channel for control of feedwater flow and hence the water level in the pressure vessel. Rapid and fine level control is provided by comparing fluid outflow and inflow. Means are provided to block automatically the flow comparison signal from the control circuit in response to a signal characteristic of a faulted flow comparison signal. At least one redundant control channel is provided and level control is transferred thereto automatically upon excusion of the water level beyond predetermined normal upper and lower limits or in response to a rapid change in the water level control signal to avoid unnecessary shutdown in the event of a faulted channel.

Abstract: A reactor vessel in-service inspection assembly (17) having an improved positioning device (80) for properly and repeatedly locating the inspection transducers (75) of the assembly within a hollow portion of the reactor vessel cavity. An acoustic transducer of the positioning device of this invention is affixed to the positioning arm (40) of the inspection transducers (75). The positioning transducer is operable to generate and simultaneously, radially direct acoustic signals around the circumference of the hollow portion of the vessel cavity and receive the signals reflected off of the cavity walls at a location within the hollow cavity. Means are provided for monitoring the received signals as a function of time. The in-service inspection assembly transducer positioning arm is arranged to automatically move in response to the monitored difference in the time of reception of the received signals to locate the positioning transducer at a preestablished location within the hollow portion of the reactor cavity.

Abstract: A toroidal plasma device has a toroidal confinement vessel defining a toroidal space and confining ionized gas therein. A solenoid which links the toroidal space induces a toroidal electric field therein to produce plasma current. A plurality of first windings are wound substantially helically around the vessel substantially equally spaced around its minor circumference. A plurality of second windings are wound substantially helically around the vessel substantially midway between successive first windings. Direct current is passed through the respective first and second windings in opposite directions with the current in the respective first and second windings equal or slightly unbalanced. The currents in the first and second windings produce a helical magnetic field.

Abstract: A method and arrangement for containing the core melt flowing from a nuclear reactor into a core catcher below the core wherein the core melt is permitted to gradually penetrate layers of a core catcher materials of inorganic reactor soluble oxides or salts disposed in the core catcher which core catcher materials are dissolved by the oxidic part of the core melt, and the molten solution, after solidification and after being cooled down to a temperature at which hydrogen generating reactions do not take place, is leached with water and rinsed out of the core catcher without the need for humans to be present in the reactor containment and to be exposed to radiation.

Abstract: The cavity within a pressure vessel for a gas-cooled nuclear reactor is divided into chambers by an intermediate support floor, with the reactor core thereabove and heat-exchangers therebelow. Separate heat-exchange units are connected to separate circulators which discharge the repressurized primary gas coolant through an annular passageway along the inner surface of the pressure vessel cavity. The heat extraction system includes a separate secondary gas coolant circuit connected to each heat-exchange unit, which coolant may be heated to about 850.degree. C. at which it is suitable to provide process heat. Emergency cooling is effected by a heat dump which is connected into each secondary circuit to promptly provide low-temperature secondary gaseous coolant which then indirectly removes the reactor core heat.

Abstract: In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180.degree. rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements.

Abstract: Device for inspecting and testing the bottom of a cylindrical reactor pressure vessel having a circular track disposed in vicinity of the bottom of the pressure vessel, including a plurality of strut members, means for connecting the strut members to the bottom of a pressure vessel, a plurality of pins extending radially outwardly from the circular track and supported in the strut members.

Abstract: There is disclosed an elongated cylindrical rod of heat-conducting and electrically-conducting material having a central bore containing a plurality of thermocouples, the hot and cold junctions of which are placed respectively in separate zones along the rod. In each zone, the hot junction of one thermocouple is fixed generally in position axially at the midway of an annular reduced-section portion of the cylindrical rod, the cold junction is located generally axially between two reduced-diameter portions and an annular insulating chamber is defined annularly opposite to each reduced-diameter portion by an outer shielding tube. The outer tube surrounds the cylindrical rod. The completed unit is to be placed within a reactor core fuel assembly to be monitored.

Abstract: At the time of starting up a nuclear reactor, the concentration of oxidizing substance in a cooling water in a reactor pressure vessel is decreased by evacuating the pressure vessel or replacing air in the vessel with an inert gas for a long time, below a predetermined level before the cooling water is heated to a temperature of 150.degree. C., thereby preventing the occurrence of stress corrosion cracking.

Abstract: A liquid metal-cooled nuclear reactor has a reactor vessel with a cover at the top thereof and is partly filled with liquid metal up to a given surface level, the liquid metal surface and the reactor-vessel cover defining therebetween a gas-filled space, at least one quasi-tight convection barrier being disposed in the space and subdividing it in elevation.

Abstract: The invention is directed to a nuclear reactor plant having a primary medium circuit including a nuclear reactor for generating a flow of heated primary working medium and a heat exchanger having a primary side to receive the flow of heated primary working medium. In accordance with the invention, a compressor is connected to the secondary side of the heat exchanger to receive a flow of secondary working medium therefrom which has been heated in heat exchange relation by the primary working medium for compression to a given temperature. By exchanging the heat at a lower temperature and subsequently pumping up the exchanged heat, a thermally highly stressed heat exchanger is replaced by a thermally highly stressed compressor.

Abstract: A nuclear reactor, control rod holding latch permits rapid insertion of the control rod into a reactor core by a ratchet and pawl mechanism arranged to lock the control rod against withdrawal, this being done through a screw which by rotation permits slow withdrawal of the control rod from the core, while keeping the control rod locked against withdrawal other than through the screw action.

Abstract: A control rod drive attaching and detaching device and a control rod drive handling device are mounted on a revolving device to be movable independently from each other. The control rod drive attaching and detaching device includes bolt handling means for loosening and tightening bolts for fastening a control rod drive to a pressure vessel of a nuclear reactor, coolant splash preventing means for disposing of coolant which flows from the control rod drive when the latter is detached from the pressure vessel, and uncoupling means for uncoupling a control rod from the control rod drive. The control rod drive handling device includes a column pivotally mounted on a carriage, a cart removably mounted on the column, and means for moving the column to a horizontal position. Each control rod drive mounted to the pressure vessel of the nuclear reactor is detached from the pressure vessel by the control rod attaching and detaching device and transferred to the cart of the control rod drive handling device.

Abstract: A hollow, biological shield assembly capable of surrounding and insulating a nuclear reactor pressure vessel positioned therein. The shield assembly includes a metallic lining attached to a radially inner wall portion of a hollow concrete body, with a layer of thermally insulating material attached to the metallic lining and a plurality of vertical cooling channels also attached to the lining and mounted in recesses formed in the concrete body.

Abstract: A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to estalish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma.

Abstract: Each of control rods inserted in the core of a nuclear reactor is coupled to a control rod driving apparatus for moving the control rod in an axial direction by a coupling mechanism including a gripper formed at a lower end of a driving extension shaft adapted to be driven by the control rod driving apparatus, and a finger mounted at an upper end of the control rod for engagement with the gripper. A cam is located in the interior of the driving extension shaft for bringing the gripper and the finger into and out of engagement with each other for coupling and uncoupling the control rod and the control rod driving apparatus.

Abstract: A control rod suspended to reciprocate in a guide tube of a nuclear fuel assembly has a hydraulic bearing formed at its lower tip. The bearing includes a plurality of discrete pockets on its outer surface into which a flow of liquid is continuously provided. In one embodiment the flow is induced by the pressure head in a downward facing chamber at the end of the bearing. In another embodiment the flow originates outside the guide tube. In both embodiments the flow into the pockets produces pressure differences across the bearing which counteract forces tending to drive the rod against the guide tube wall. Thus contact of the rod against the guide tube is avoided.

Abstract: A boiling water type nuclear reactor adapted to be operated at a void quality (weight ratio of vapor in the coolant) of coolant at the core outlet of 17% or higher. By adopting this level of void quality, a void quality exceeding 8.5% is available at least in the upper half region of the core which in turn provides a void fraction of 66% or higher. Consequently, it is possible to reduce the enrichment of the fuel, so as to allow a more efficient use of the fuel. At the same time, due to the reduced power generating rate, the range over which the flow rate of coolant is controlled is widened, so that it becomes possible to change the reactivity solely by controlling the flow rate of the coolant. It is therefore possible to operate the reactor over whole operation cycle with its control rods fully withdrawn.

Abstract: A system for generating steady state confining current for a toroidal plasma fusion reactor providing steady-state generation of the thermonuclear power. A dense, hot toroidal plasma is initially prepared with a confining magnetic field with toroidal and poloidal components. Continuous wave RF energy is injected into said plasma to establish a spectrum of traveling waves in the plasma, where the traveling waves have momentum components substantially either all parallel, or all anti-parallel to the confining magnetic field. The injected RF energy is phased to couple to said traveling waves with both a phase velocity component and a wave momentum component in the direction of the plasma traveling wave components. The injected RF energy has a predetermined spectrum selected so that said traveling waves couple to plasma electrons having velocities in a predetermined range .DELTA.. The velocities in the range are substantially greater than the thermal electron velocity of the plasma.