Abstract: An apparatus and process for the accurate measurement and calibration of core flow in a boiling water reactor is disclosed. The reactor includes a pressure vessel having internal forced circulation through the core. An annular downcomer region establishes reactor coolant flow downwardly in the periphery of the reactor vessel and finally upwardly and centrally into the core across a core plate. A pressure sensor detecting the pressure differential across the core plate is utilized. This pressure sensor has its measurement enhanced by input from local power range monitors in the core to utilize both the sensed pressure differential and the power to predict more accurately flow in the reactor. An algorithm is developed for utilizing the pressure differential and the real time readings from the local power range monitor to accurately gauge overall reactor coolant flow. To ensure accurate calibration, two calibration standards are itilized at steady states of reactor power output and coolant flow.

Abstract: An inductive flow probe for measuring the flow velocity of a stream of liquid metal by insertion of the probe into the stream. The probe includes a probe tube having first and second regions therein, at least one permanent magnet disposed in the first region for providing a magnetic field with a direction substantially transverse to the direction of the stream, and a first pair of thermoelements positioned in the first region within the magnetic field. The invention further includes a second pair of thermoelements positioned in the second region outside the magnetic field and an evaluation circuit coupled to the first and second pairs of thermoelements. The evaluation circuit generates a temperature-compensated signal corresponding to the velocity of the stream of liquid metal.

Abstract: An apparatus for measuring the flow rate of electrically conductive liquids includes two coils disposed in succession as seen in the flow direction of a liquid. The coils are switched in alternation as a primary and a secondary coil. One of the coils is excited with an alternating current as the primary coil, and voltage induced by the excitation in the other of the coils as the secondary coil is measured.

Abstract: The ultrasonic wave sensor (2) according to the invention comes into contact with a wall at a high temperature (1) by means of a wave guide (5) made of a vitro-ceramic material. The sensor includes, inside a body (3) made of metallic material, a piezoelectric ceramic pellet (8) connected to an electrical power supply or measurement leads (9). The wave guide (5), also placed in the body (3), is in contact by one of its ends (5b) with the piezoelectric pellet (8) and by its other end (5a) with the wall (1). The body (3) of the sensor is mounted in an articulated manner on a support (21) fixed to the wall (1). The invention applies in particular to the measurement of flow rate in a primary duct of a pressurized-water nuclear reactor.

Abstract: An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The mixture then passes through a combustion chamber where hydrogen gas in the form of H.sub.2 or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

Abstract: An apparatus for measuring and indicating mass throughput of a fluid moved in a channel by a processing machine includes first to fourth measurement value pickups, first to third divider stages, first to fourth resistances, first to fifth multiplier stages, an adder for forming a difference ##EQU1## between an output signal of the first divider stage which is weighted with the first resistance, a memory of characteristics of the processing machine which has stored therein an appertaining volume number as a function of a magnitude of an output of the second divider stage and of the fourth measurement value pickup, and a measurement value indicator for indicating an output of the third divider stage weighted by the fourth resistance which is the mass throughput ##EQU2##

Abstract: An ultrasonic cleaning device for a venturi flow nozzle in a pipe in a fluid system which includes one more transducer assemblies for generating and transmitting sound waves to the nozzle to effect a cleaning action.

Abstract: This invention relates to a control system for heat supply as hot water from nuclear power plants equipped with condensation units. This leads to the increased efficiency of the nuclear power plant on the basis of heat extraction from the turbine and its utilization for district heating with hot water as agent. The system requires a turbine nonadjustable bleeding through which a steam flow is extracted. A flow nozzle for steam flow measurement is provided on the steam transport line, a pressure transducer which sends a signal to a comparing and control unit which receives also a signal from another pressure transducer located on the turbine first stage. The comparing and control unit actuates the motorized steam and condensate valves, performing the turbine protection in case that the steam flow extracted at the nonadjustable bleeding exceeds the allowed limit.

Abstract: An emergency feedwater system for the steam generators of a pressurized water nuclear reactor has two separately located subsystems, each subsystem supplying water to at least one steam generator when activated, where each subsystem contains an emergency feedwater supply tank, and a pair of emergency feedwater lines leading from the tank which communicate with the inlet line of a steam generator. An electrical operated motor driven pump is located in one of said pair of emergency feedwater lines and a steam turbine driven pump in the other of said pair, with a cavitating venturi provided in an emergency feedwater line between the pump and inlet line of the steam generator. The system is adaptable for use with two, three, and four loop pressurized water reactor systems.

Abstract: A method and an apparatus for feed-water control in a steam generating plant such as a boiling water nuclear reactor having motor-driven feed-water pumps and turbine-driven feed-water pumps for supplying feed-water to a steam generator, in which the feed-water flow through the turbine-driven feed-water pumps is controlled to be maintained constant, while reducing the recirculation flow discharged from the turbine-driven feed-water pumps and fed back to the inlet thereof, so as to reduce the amount of feed-water supplied to the steam generator by the motor-driven feed-water pumps, whereby variation of water level in the steam generator during switching between the two kinds of feed-water pumps is suppressed.

Abstract: A sensor for monitoring the interior of a sodium-cooled fast breeder reactor comprises a pair of symmetrical magnetic cores, a magnetostrictive or piezoelectric vibrator element bonded to one of the cores, a primary coil and a plurality of secondary coils surrounding the magnetic cores, and a container enclosing the above members. The primary coil applied with an exciting alternating current generates an acoustic signal voltage indicative of sound, if any, originated in the interior of the reactor. The magnetic flux produced by the exciting current is influenced by the temperature and flow velocity of sodium flowing around the sensor, and corresponding voltage signals resulting from the changed magnetic flux are induced in the secondary coils.

Abstract: Failed fuel detection apparatus for nuclear reactors cooled by liquid metal has a pump (11) for impelling coolant metal along sampling pipes (10) to outlet points (10a) in the pipes. A rotary collector (15) is provided to scan the outlet points with a gap between the outlet points and the collector across which coolant in the sampling pipes can be impelled. The pump (11) is preferably of the helical annular linear induction type with the pipes passing through the annulus of the pump while being wetted internally and externally by liquid metal.

Abstract: A device for measuring the flow rate of a fluid in the annular space of a steam generator; having within a probe housing, kept fixed relative to the outer wall of the steam generator, a probe. A seal between the probe and the probe housing is formed by an elastic bellows fitted in such a way that it constantly applies one end of the probe against the inner wall of the generator.

Abstract: A system for controlling the feedwater system in a nuclear power plant is disclosed. The system utilizes a logic calculations subsystem (50) which selects the operational mode of the system to be monitored from a plurality of operational modes. A disturbance estimate calculations subsystem (52) contains a dynamic mathematic model of the feedwater system and compares measured system variables with corresponding dynamic model variables contained therein to produce signals representative of deviations therebetween. A modified feedforward calculations subsystem (54) utilizes these signals and other system parameters as inputs to a steady-state mathematical model to produce control signals to determine valve positions and pump speeds so that the control valve flows, minimum control valve pressure drop, and feedwater pump flows are at their respective demanded values.

Abstract: An ultrasonic flaw detector device including axial and circumferential fixed tracks located in a space defined between a pressure vessel of a nuclear reactor and a heat insulating wall surrounding the vessel and arranged axially and circumferentially respectively of the pressure vessel of the nuclear reactor. A rotary track is located at a junction of the axial fixed track and the circumferential fixed track and moved in rotary movement by a chain and has its angle of rotation restricted by a pair of stoppers. A carrier member supporting an ultrasonic probe is moved on the tracks to effect ultrasonic flaw detection to detect any flow that might be present in the pressure vessel. To transfer the carrier member from the axial fixed track to the circumferential fixed track, the carrier member is first transferred from the axial fixed track to the rotatable track, and after the rotary track is rotated, the carrier member is transferred from the rotatable track to the circumferential fixed track.

Abstract: Disclosed is an improved permanent magnet flowmeter capable of withstanding bending stresses in the direction of induced emf signals. The flowmeter includes a unique terminal arrangement integrally formed with the flowmeter by trepanning opposing wall sections of the flowmeter body. The terminal arrangement provides increased flowmeter sensitivity by increasing the strength of the induced emf signals.

Abstract: An apparatus for measuring the flow of gas in a blower of a gas cooled high temperature nuclear reactor comprising a blower, a blower shield communicating with the blower, an inlet conduit in the blower shield for conducting gas flow to the blower, an exit conduit in the blower shield for conducting gas flow from the blower and means for measuring the flow of gas in the exit conduit. The measuring means includes a venturi tube having a narrowed area in the exit conduit, a first measuring channel in communication with the gas flow in the narrowed area, a second measuring channel in communication with the gas flow in the exit conduit upstream from the narrowed area, and means for comparing the relative gas flow in the first and second measuring channels. A transducer connected to the first and second measuring channels performs the comparing and measuring steps.

Abstract: This invention teaches improved apparatus for the method of detecting a breach in cladded fuel used in a nuclear reactor. The detector apparatus uses a separate bypass loop for conveying part of the reactor coolant away from the core, and at least three separate delayed-neutron detectors mounted proximate this detector loop. The detectors are spaced apart so that the coolant flow time from the core to each detector is different, and these differences are known. The delayed-neutron activity at the detectors is a function of the dealy time after the reaction in the fuel until the coolant carrying the delayed-neutron emitter passes the respective detector. This time delay is broken down into separate components including an isotopic holdup time required for the emitter to move through the fuel from the reaction to the coolant at the breach, and two transit times required for the emitter now in the coolant to flow from the breach to the detector loop and then via the loop to the detector.

Abstract: A system for monitoring coolant conditions within a pressurized vessel. A length of tubing extends outward from the vessel from an open end containing a first line restriction at the location to be monitored. The flowing fluid is cooled and condensed before passing through a second line restriction. Measurement of pressure drop at the second line restriction gives an indication of fluid condition at the first line restriction. Multiple lengths of tubing with open ends at incremental elevations can measure coolant level within the vessel.

Abstract: In supervising the channel stability of a nuclear reactor, the thermal power and the coolant flow quantity in each fuel assembly are determined by signals produced by a plurality of neutron flux detectors installed in the nuclear reactor, and signals regarding other operating conditions of the reactor, and the thermo-hydrodynamic stability of each fuel assembly is judged by the above-mentioned thermal power and coolant flow quantity as well as the measured values of such parameters as inlet subcooling of the core and of the pressure in the reactor vessel. Or the stability limit of a selected one of the parameters is determined. Then, the threshold of the thermo-hydrodynamic stability or the stability limit is compared with the actually measured value thereof so as to determine a stability margin.

Abstract: A nuclear reactor having a vertical annular space defined between a shroud enclosing a reactor core and a pressure vessel surrounding the shroud, and a plurality of internal circulation pumps disposed in a lower portion of the space for forcing a coolant in the space to flow into below the reactor core so that the coolant flows through the core in forced circulation. A tubular guide member is disposed adjacent to a suction port of each internal pump for vertically guiding a flow of the coolant being sucked into the pump to increase the effective inertia of the flow of the coolant, thereby to enhance the stability of the flow conditions of the coolant flowing through the reactor core.

Abstract: A method for detecting the flow instability in steam generators is provided. First, a number of limit values on the differential pressure between the water-side inlet and outlet of the steam generator are determined at different feedwater flow rates. The limit values define the onset of the flow instability. By connecting the thus determined limit values, a boundary line defining the occurrence of the flow instability is obtained. Second, it is checked whether the measured differential pressure between the inlet and outlet at an actual feedwater flow rate is above or below the boundary line so as to determine if the flow instability has occurred or not in the steam generator. An apparatus for accomplishing the method is also provided.