Abstract: Coolant flow (900) in the core (103) of a natural circulation boiling water reactor (100) is monitored by making use of a detector (208) for nuclear radiation and a turbine device (204) which comprises a rotor (304) which can modulate the flux (206) of the nuclear radiation on the detector. The turbine rotor can be installed in a fuel bundle (104), while the detector can be placed in an adjoining instrumentation tube (320). Included in the turbine rotor is material (308) which modulates the radiation field (neutron field and/or gamma field). The radiation detector detects (602) variations in the radiation field when the turbine rotor device is set into rotation by the coolant flow (900). The coolant flow rate is then calculated (603) from the speed of these variations.

Abstract: The manipulator has a base including an elongated bar having a center between first and second opposed ends. Fluidly actuated end effectors at the first and second ends of the base, are extensible for bracing the base against opposed support surfaces on the steam generator, such as locator pins situated within the clamp ring. A rigid arm is connected to the center of the base and extends radially to a free end. A first drive means is provided for remotely rotating the arm around a rotation axis passing through the center perpendicularly to the base. The preferred transducer means include a bracket situated at the free end of the arm, a pair of radially spaced apart mounting posts supported by the bracket and extending in parallel with the rotation axis, and a transducer shoe assembly carried by each post. A transducer element is mounted in each of the shoe assemblies.

Abstract: This invention defines a combined inspection procedure using ultrasonic techniques for detection of hydrogen attack damage in material. The procedure comprises an initial scanning procedure for locating areas suspected of being damaged by hot hydrogen. The initial scanning procedure is a pattern-based backscattering test that provides a pattern which is classified as falling within at least one of four backscattering pattern category types. Follow-up test procedures based upon the pattern type are then performed. These tests include spectrum analysis, velocity ratio, spatial averaging backscattering, and frequency dependence for assessing whether the material has hydrogen attack damage and the extent of hydrogen damage in the suspect areas. Should hydrogen attack damage be identified, the velocity ratio and spectrum analysis tests can then be used to determine mechanical properties of the hydrogen attack damaged material.

Abstract: Apparatus and method for inspecting a tubular member for degradation, which tubular member may be a control rod drive mechanism (CRDM) penetration tube of the kind typically found in nuclear power reactor pressure vessels. The CRDM penetration tube includes a thermal sleeve concentrically disposed therein, the sleeve being radially rotatable and axially translatable within the tube. However, the sleeve may be nonhomogeneous, which nonhomogeneity could undesirably mask the inspection signal as the inspection sensor is radially and axially moved in order to inspect the tube.

Abstract: An ultrasonic method of inspecting repaired stub tubes in a boiling water reactor. The top and bottom ends of each stub tube are respectively welded to the corresponding control rod drive housing and to the bottom head of the reactor pressure vessel. Under certain conditions, a crack can form in the heat-affected zone of the stub tube adjacent to the upper weld, necessitating repair by installing a mechanical seal. A probe inserted in the control rod drive housing has transducers which transmit pulsed ultrasonic energy toward a machined surface-air gap interface disposed to reflect the pulse trains generally axially through the stub tube. The radial and azimuthal dimensions of a radial crack in the stub tube are determined in dependence on which pulsed trains are reflected back to the probe by the crack via the interface.

Abstract: A nuclear fuel identification code reader has an optical sensor for detecting a nuclear fuel identification code marked on a fuel assembly and an ultrasonic wave sensor for detecting the nuclear fuel identification code. It further has first means for recognizing the nuclear fuel identification code based on information derived from the optical sensor and second means for recognizing the nuclear fuel identification code based on information derived from the ultrasonic wave sensor. When the nuclear fuel identification code cannot be recognized by the first means, the detection by the ultrasonic wave sensor and the recognition of the nuclear fuel identification code by the second means are effected. The nuclear fuel identification code can be recognized in a short time with a high accuracy.

Abstract: A non-intrusive vibration measurement system and method using commercial ultrasonic instruments together with digital signal filtering and analysis techniques is adapted to quantitatively detect vibrations as small as 0.04-inch peak-to-peak. The system and its methodology is used for in-service vibration monitoring of internal components of check valves, pumps, nuclear reactors, steam generators and heat exchangers, especially when the vibration frequency is too low for quantitative analysis by accelerometers and when the strain induced is too low for strain gauge analysis, and when the vibrating component is in an "encased" environment.

Abstract: An ultrasonic level measuring system includes a transducer mounted on the bottom of a pipe which launches acoustic pulses up through the pipe wall into the water. The pulses are reflected from the water surface and received by the transducer along with pulses reflected by the pipe wall and reverberations within the pipe wall. The system has a monitor mode in which a variable threshold for the reflected pulses is set by dividing the time after a trigger pulse into time bins and automatically establishing a threshold level for each time bin. In a signal search mode, the time bin containing the liquid level is identified from a histogram recording reflected pulses which exceed the threshold levels for the various time bins. In a normal operating mode, foreground calculations precisely calculating the liquid level in the identified bin alternate with background calculations which reassess the identification of the time bin containing the liquid level.

Abstract: This probe comprises a cable (4) and a probe head (6) fixed to one end of the cable and having an inspection head (18) provided with transmission-reception means (22, 24) for inspection signals from a tube (2), a support (20) on which the inspection head is mounted in rotary manner, a motor (66) for rotating the inspection head, an encoder associated with the motor for determining the circumferential extent of faults which the tube may have, and a rotary collector (10) between the motor and the support in order to ensure a mechanical connection between the motor and the inspection head and the transmission of control signals for the said means (22, 24) and signals supplied by the latter. Articulated mechanical connections (14, 16) are provided between the motor and the collector and between the collector and the inspection head.

Abstract: A non-intrusive vibration measurement system and method using commercial ultrasonic instruments together with digital signal filtering and analysis techniques is adapted to quantitatively detect vibrations as small as 0.04-inch peak-to-peak. The system and its methodology is used for in-service vibration monitoring of internal components of check valves, pumps, nuclear reactors, steam generators and heat exchangers, especially when the vibration frequency is too low for quantitative analysis by accelerometers and when the strain induced is too low for strain gauge analysis, and when the vibrating component is in an "encased" environment.

Abstract: A method of ultrasonic inspection of a reactor nozzle involves positioning emitter and receiver transducers on the exterior vessel wall near the nozzle. The emitter transducer is positioned and oriented so that it generates both primary longitudinal and transverse beams. The primary longitudinal beam is directed at the inner radius of the nozzle. The transverse beam is directed toward the interior vessel wall at an angle of about 30.degree. to the normal. Most of the energy of the transverse beam is converted to a secondary longitudinal beam also directed toward the inner radius of the nozzle. The receiver transducer is positioned on the exterior vessel wall about 4" from the emitter transducer so as to be able to detect reflections of both the primary and second longitudinal beams from any potential defect in the nozzle volume adjacent the inner radius.

Abstract: A method and apparatus for eliminating erroneous test readings during ultrasonic testing of nuclear fuel rods is disclosed. The method and apparatus employ the use of an alignment guide to effect temporary alignment of the fuel rods during testing in order to overcome mechanical deviations of the rods. The alignment guide includes elongated, parallel guide bars for insertion into an array prior to ultrasonic testing. The bars are mounted on a base which, in turn, is movably mounted on a support element. A fixed guide maintains the relative position of the guide bars with respect to one another. A hydraulic element causes the guide bars to be inserted and removed from the fuel array. In a preferred arrangement, the alignment guide may be removably mounted on a frame containing the ultrasonic testing equipment.

Abstract: The inspection head component of a manipulator employed in the inspection of the interior surface of a nuclear reactor vessel is aligned to an optimum orientation when positioned at a local surface to be inspected. This alignment is carried out by generating ranging information with respect to the local surface using ranging ultrasonic transducers positioned upon the inspection head. The propagation interval of the acoustic signal emitted by these ranging transducers is timed and quantified to develop orientation error signals. Such development is carried out in conjunction with known values for the local surface being inspected and in conjunction with a sequence of data collection at the position. The inspection head is pivotally mounted upon the manipulator so as to be movable about at least two axes by inspection head positioning assemblies which may be provided, for example, as stepper-motors and associated translational movement components.

Abstract: A fuel pellet surface defect inspection apparatus has an infeed conveyor, a discharge conveyor, and a slide and inspection assembly between the conveyors. The assembly includes a slide defining an inclined track having exit and entry ends adjacent the respective discharge and infeed conveyors. The entry end is at a higher elevation than the exit end. The assembly also includes an inspection station located along the track between its entry and exit ends. The station has lower and upper sound reflectors configured to define an annular inspection chamber through which a pellet moves as the pellet slides down the inclined track. The chamber completely encloses the cylindrical surface of the pellet as the pellet moves through the chamber. An ultrasonic inspection head is mounted at the station and transmits and receives sound energy to and from a pellet as it moves through the chamber such that the sound energy completely surrounds the moving pellet being inspected within the chamber.

Abstract: An automated system for examining incore housing welds in a nuclear reactor from above is disclosed. The probe uses both ultrasonic and eddy current non-destructive inspection coils to examine the weld for indications, or flaws. It is inserted into the incore housing tube from above because of the high radiation exposure workers experienced using the prior method of inserting a probe into the incore housing from below. This is conveniently done when the incore flux monitors are removed during standard maintenance, and is performed from the refueling bridge.

Abstract: An apparatus and process for controlling a high pressure fluid leak, such as a combustible gas, by determining the leak rate of the fluid from the leak source utilizing sound sensors wherein the step of determining the leak rate includes the step of comparing the signals from the sound sensors with a known standard curve, and activating a controller for controlling the fluid to prevent the fluid from spreading in the atmosphere.

Abstract: The assembly (1) is immersed in the water of a pool and placed in vertical position. Detection of the rods (6) of the assembly exhibiting cracks giving rise to leakage is ensured by transmission of ultrasonic waves along the length of each of the rods (6) and by measuring the attenuation of the ultrasonic waves due to the presence of water inside the rods (6) whose cladding is cracked. The ultrasonic waves are picked up after propagation on the cladding of the rods (6) of the assembly along their length, below the lower end fitting (5) in place on the assembly (1). The detecting device comprises an ultrasonic transducer (11) capable of transmitting ultrasonic waves along the length of the rod from its upper part, and a receiver probe (16) for the ultrasonic waves, placed under the lower end fitting (5).

Abstract: An improved apparatus and method for ultrasonic inspection of materials through barriers such as gaps in manufactured parts is disclosed. The improvement herein is directed to enabling such ultrasonic testing to bridge ambient gaps such as intentionally formed gaps in composite structures having a first structure for originally receiving and transmitting sound separated by the gap from another structure to be inspected. Preferably, the gap is flooded with a gas having a predictable and optimum speed of sound relative to the material of the first and second structures. Sound is propagated to the first structure in a wave packet that is transmitted through the couplant fluid. The sound is generated in a wave packet having a spatial width at least twice the dimension of the gap to be bridged. The wave packet has a contained frequency having a wavelength (relative to the speed of sound of the gas flooding the gap) to create a constructively interfering standing wave node within the gap.

Abstract: A system and method for determining the condition of one or more parameters of a valve, e.g., particularly a check valve in a fluid carrying pipe, by monitoring fluid turbulence downstream of the valve. An ultrasonic transmitter-receiver transducer pair provides a signal modulated by the fluid turbulence, which signal is demodulated and processed to obtain a signature or other signal indicative of the valve condition. The processes signature signal may additionally be compared with a measure of flow rate determined just upstream from the valve. By operating the ultrasonic system at high frequency and using appropriate detecting circuitry, low frequency interference from mechanical shocks and vibrations is avoided, yielding a reliable detection of the flow turbulence caused by the valve.

Abstract: An apparatus and method to facilitate the in situ detection of small leaks in fluid-filled, capacitive type pressure transducers by remotely and non-intrusively inducing a brief time varying transient signal, and then analyzing the frequency response of the transducer to such excitation in order to detect the presence and effects of a fluid leak. The adverse effect of this induced transient signal on the process control circuitry is insignificant, while providing for an accurate and sensitive method for detecting the extent of fluid loss in the transducer when evaluated according to the present invention. As a consequence of such transducer evaluation techniques, frequency responsive characteristics of such devices may be recorded and self-correlated over long periods of time.

Abstract: Nuclear fuel cladding tube end plug welds are ultrasonically scanned to develop data indicative of weld thickness, weld penetration, and the existence and size of any included feature, such as pores. A computer analyzes the data to determine critical weld characteristics which are then tested against established quality assurance standards to see if the end plug weld is acceptable, all on an automated production line basis.

Abstract: A system for detecting steam voids or bubbles within a reactor coolant system. A dynamic pressure transducer detects pressure fluctuations in the coolant system and produces signals representative of steam voids within the system. The signals produced by the transducer are conditioned and applied as an input to a microprocessor along with other inputs representative of other operating parameters for the reactor coolant system. The microprocessor adjusts the signals representative of steam voids within the system and displays same to the operator.

Abstract: A nuclear fuel identification code reader has an optical sensor for detecting a first nuclear fuel identification code marked on a fuel assembly and an ultrasonic wave sensor for detecting a second nuclear fuel identification code marked on the fuel assembly. It further has first means for recognizing the nuclear fuel identification code based on information derived from the optical sensor and second means for recognizing the nuclear fuel identification code based on information derived from the ultrasonic wave sensor. When the nuclear fuel identification code cannot be recognized by the first means, the detection by the ultrasonic wave sensor and the recognition of the nuclear fuel identification code by the second means are effected. The nuclear fuel identification code can be recognized in a short time with a high accuracy.

Abstract: An apparatus and method for scanning the outer profile of control rods in a control rod assembly includes a plurality of rotatably mounted ultrasonic transducers which are mounted for rotation about the axis of at least some of the control rods in the assembly. The assembly is moved in a linear path parallel to the axis of the control rods, past the rotating transducers for scanning the surfaces of the control rods in helical paths. By distributing the transducers in a selected configuration, all control rods in the assembly can eventually be scanned.

Abstract: Nuclear fuel cladding tube end plug welds are ultrasonically scanned to develop data indicative of weld thickness, weld penetration, and the existence and size of any included feature, such as pores. A computer analyzes the data to determine critical weld characteristics which are then tested against established quality assurance standards to see if the end plug weld is acceptable, all on an automated production line basis.

Abstract: A simple and accurate method for determining the enthalpy of wet steam using pressure and moisture content values. Moisture content is determined by measuring sonic velocity of the steam, which is dependent upon enthalpy. A small sample of the wet steam is superheated by pressure reduction to a single-phase state prior to measuring its sonic velocity in order to achieve greater accuracy of this measurement. From its sonic velocity, enthalpy of the sample is calculated. Since the process takes place at constant enthalpy, the enthalpy value of the sample is the same as that of the fluid from which it was drawn.

Abstract: Fluid leakage from a crack or other leakage point and other vibration-generating events in pipes and conduits may be located and analyzed by sensing axial and torsional vibrations and pressure fluctuations created by such events by placing accelerometers and/or strain gauges and pressure sensors on the conduit at selected points. The location of the event may be determined by comparing the travel time of selected pairs of signals such as axial propagated signals as compared with torsional propagated signals as a result in the difference of the acoustic wave speed of axial versus torsional waves. Cross correlation and deconvolution processes are carried out on the measured signals to determine differential signal arrival times at the sensors and to eliminate pipe response signals.

Abstract: The device comprises a flexible pipe (15) having one of its ends in a zone (20) situated outside the water box (6) and its other end joined to a tubular probe-guide (16) supported by a handling device (13, 14) inside the water box (6). A sheath (21) is slideably mounted inside the flexible pipe (15) and has mounted at one of its ends a stop and a bush for guiding the ultrasonic probe (18). A Bowden cable (22) is mounted rotatably about its axis inside the sheath (21), and is integral at one of its ends with a profiled rotational driving part and joined at its other end, outside the water box (6), to a motor (24). The support for the probe (18) has a threaded part engaged in a tapped part of the guide bush and can be driven in rotation by a profiled part integral with the end of the Bowden cable (22). The support for the probe (18) is thus driven in rotation and axial translation so as to perform a helical movement.

Abstract: A drive unit for gripping and rotating a fuel rod during inspection of the fuel rod. A housing has a drive motor mounted at its first end with a spindle rotatably mounted in the housing and directly coupled to the drive motor. A recess at one end of the spindle adjacent the second end of the housing receives a substantially donut shaped rubber bladder. A flanged port that extends radially from the bladder and is in fluid communication with the interior of the bladder provides a means for pressurizing the bladder. This causes radial inward expansion of the bladder for gripping a fuel rod to be inspected.

Abstract: A multi-point wall thickness gage (10) comprises a pad (16) of flexible magnetic material that includes an array of ultrasonic transducers (13) and a multi-point ultrasonic transmitter and receiver (25) to which each transducer (13) is attached. The magnetic pad (16) is attachable to the wall of a ferro-magnetic object (19), and serves to hold the array or matrix of ultrasonic transducers (13) against the wall of the object. The specific region of the object wall being inspected is marked off (17), and the magnetic pad (16) is periodically applied over this region (17). The output of the transducers (13) is used to detect whether any wall thinning is occurring over the particular area of the object covered by the magnetic pad (16), and if so, the particular pattern of thinning within the area. Trend monitoring is simplified since exact relocation of the transducers (13) for periodic measurements is more readily accomplished.

Abstract: Nuclear fuel rods are checked for the presence of water in their interior by injecting bursts of ultrasound radially into the wall of each tube, producing echoing back and forth between the inner and outer surfaces of the tube. The rate of decay of this echoing indicates whether or not water is present.

Abstract: An apparatus for the inspection of nuclear reactor fuel rods combined in fuel rod clusters with spaces therebetween in a fuel assembly includes test probes each being disposed at a different respective level along the fuel assembly. Fingers are each part of a respective one of the test probes. Ultrasonic test heads are each disposed on a respective one of the fingers. The test heads are inserted into the spaces between the fuel rods, and the insertion position of each of the test probes is corrected independently of the insertion position of the others of the test probes, before insertion of the test probes.

Abstract: An apparatus for the inspection of a nuclear reactor fuel assembly in a water-filled pool having fuel rods with spaces therebetween includes an encapsulated housing having walls and being disposed in the water-filled pool. A lever drive mechanism is disposed in the housing. A rotary transmission connected to the lever drive mechanism extends through one of the walls of the housing toward the surface of water in the pool. A plurality of stationarily disposed lever linkages jut out from the rotary transmission outside the housing. Each of the lever linkages has an end facing away from the rotary transmission. Carriers are each connected to a respective one of the ends of the lever linkages. Probes are each disposed on a respective one of the carriers. Ultrasonic test heads are each disposed on a respective one of the probes for insertion into the spaces between the fuel rods.

Abstract: An arrangement for inspecting the fuel assemblies of boiled water reactors using an ultrasonic transducer probe. Each assembly contains a square array of fuel rods covered by a fuel channel slip. The probe accesses the fuel rods through a nosepiece in the shape of an inverted tripod located at the bottom of each assembly. The fuel rods are supported in each assembly by upper and lower tie plates, in the form of grids. The grids have first apertures for supporting the ends of the fuel rods, and second apertures which allow coolant water to flow between the fuel rods during operation. The probe is inserted through the second apertures of the lower tie plate grid, and rotated to inspect each of the four surrounding fuel rods for the presence of water inside the fuel rods.

Abstract: In a boiling water reactor, an apparatus and process for ultrasound inspection of the top guide is disclosed. The top guide constitutes a lattice of stainless steel bars overlying the core plate and being assembled at confronting grooves with the lattice mounted at the side edges to the reactor pressure vessel. This lattice braces the upper ends of the vertically supported fuel assemblies in their requisite orientation and spaced apart relation to enable among other things the required spatial interval to be maintained for control rod moderation of the reaction. Because of the proximity of the top guide to the fuel assemblies, the individual bars making up the lattice need to be checked for cracking, especially that cracking produced by irradiation assisted stress crack corrosion. With a defined cell in the lattice emptied of its contained and adjoining fuel assemblies, there is disclosed an ultrasound test for cracking.

Abstract: A method for checking the dimensions of a fuel assembly for nuclear reactors formed of a bundle of longitudinally extended fuel rods disposed in rows in a water tank defining gaps between the rows includes moving two mutually parallel probes with respective ultrasonic test heads at free ends thereof relative to the fuel assembly, inserting the probes laterally into the gaps between the fuel rods accommodating a row of fuel rods between the probes, transmitting ultrasonic waves with one of the ultrasonic test heads, receiving the ultrasonic waves with the other ultrasonic test head, continuing irradiation during the movement of the probe, determining at least one of the height and width of a peak of the ultrasonic waves associated with a water path between the transmitting and receiving test heads, and using at least one of the height and width of the peak to determine the spacing between two fuel rods.

Abstract: A mechanical delivery system for remotely positioning an ultrasonic sensor in mating engagement with a component to be inspected has an elongated support which can be manipulated at a first end from a remote location. A second end has an arm for carrying the sensor. A pin connects the arm to a housing which has an opening therein. A pinion gear is connected to the arm and a mating rack gear is connected to an actuator rod for moving the arm between a first position parallel to and within the housing and a second position wherein that portion of the arm carrying the sensor extends laterally of the housing through the housing's opening. The sensor is mounted on the arm such that it is permitted limited rotation about an axis perpendicular to the arm and limited rocking about a point on that axis thereby enabling the sensor to engage the component as a result of manipulation of the first end of the elongated support despite mispositioning of the second end of the support relative to the component.

Abstract: A mechanism for testing fuel tubes in nuclear fuel bundles includes a carriage, carrying an elongated probe, and a grooved plate. The grooves are parallel to the probe and are spaced by the same distances as rows of tubes in the fuel bundle. They are connected at at least one end. A pin on the carriage fits in the grooves. A hydraulic cylinder reciprocates the carriage longitudinally of the grooves and a pneumatic cylinder urges it laterally, so that the pin moves from groove to groove at the end of each stroke.

Abstract: Defective fuel elements in an assembly immersed in a liquid are detected using ultrasonic absorption. A train of ultrasonic waves having a frequency and duration such that propagation takes place as Lamb waves is applied to an end portion of the sheath. The echoes are detected. Transmission and detection are repeated for different frequencies. Some frequencies are in a range corresponding to absorption by water which may be contained in the sheath. Other frequencies correspond to a range for which there is an echo at a mechanical defect of the sheath, such as a crack.

Abstract: An ultrasonic transducer carried by rod means of dimensions such that it may be inserted in the assembly between an end piece and the caps of the element, and a crossed movement moving mechanism for bringing the transducer above the different elements. It further comprises a mechanism for moving rod elements in the longitudinal direction of the fuel elements. The transducer is set up on rod elements with at least one degree of freedom about a shaft transversal to the fuel elements so as to be able to be applied flat against the end face of a cap.

Abstract: A method for locating defective fuel rod cladding tubes of a water-cooled nuclear reactor within fuel rod bundles combined to form complete fuel assemblies disposed in a water-filled fuel assembly storage pit, including a mooring, a carriage disposed on the mooring, a manipulator disposed on the carriage and having a water proof space disposed therein, driving elements of the manipulator disposed in the water proof space, probes disposed directly in the water of the pit and connected to the driving elements, at least one ultrasonic test head disposed on each of the probes, and a lifting device for holding the fuel assemblies, includes: centering a fuel assembly to be tested on the mooring with the lifting device, moving the carriage into a test position, and transmitting motion cycles of the driving elements in the water proof space to the probes in the water of the pit for moving the probes and the test heads between the cladding tubes, and a device for carrying out the method.

Abstract: Apparatus for measuring the pitch between adjacent rods in a row of spaced-apart rods in a nuclear fuel assembly at selected points along the length of the rods, wherein the fuel assembly is relatively positioned angularly about its longitudinal center line with respect to a wand positionable to any selected point along the length of the rods carrying two spaced-apart, non-contact proximity sensors is transversely moved along the row of rods. An output signal of unique value is generated when the sensors are equally distant from a rod or adjacent rods. Means are provided for measuring the distance between the occurrence of the alternate unique signals as a measure of the pitch between adjacent rods.

Abstract: An ultrasonic probe for the weld inspection of nuclear reactor vessel nozzles is constructed from a plurality of segments interconnected by means of a flexible joint and protected by bumpers of various shapes. The probe is capable of successfully operating in an underwater and radioactive environment under remote control while maintaining a high degree of control over the placement and movement of the included transducer assembly for performing contact type testing. The transducer assembly, which includes an ultrasonic transmitter and receiver, is mounted within an ultrasonic sensor body which permits insertion of the probe within a nozzle of a reactor vessel while maintaining direct surface to surface contact with the nozzle for weld area examination by contact type testing.

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: Process and apparatus for examining a fuel assembly of a nuclear reactor. The apparatus includes a support on which is positioned the assembly to be examined, a wave transmitting source directed towards the assembly to be examined, a mechanism for examining the assembly receiving the waves transmitted by the source and which have been reflected by the assembly. The examining mechanism includes a spindle directed towards a mirror, which is inclined in such a way that it reflects the waves reflected by the assembly towards the examining mechanism, and a device for providing protection against radiation emitted by the assembly, the device being positioned between the assembly and the examining mechanism.

Abstract: An apparatus is disclosed for inspection of tubing, and more particularly, the determination of the extent of erosion in the wall of a heat exchange tube of a nuclear reactor. An ultrasonic transducer assembly is movable axially and rotatably in a helical path for producing both thickness and position signals to provide a map of wall thickness.

Abstract: To monitor the deterioration of a weld (10) between a tube (11) and tube plate (12) which has been repaired by a repair sleeve (14) inside the tube and brazed at one end to the tube, ultrasound from a crystal (21) at the end of a rod (24) is launched into the tube through the braze (15) and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld.

Abstract: Apparatus for detecting the evolution of an acoustic signal, comprising an acoustic sensor, as well as circuits for the amplification, filtering, detection and measurement of the effective value of the signal supplied by the sensor. The apparatus comprises a smoothing circuit, a sawtooth generator, an adder, a circuit for adjusting the effective value by straight segments and a circuit for carrying out sequence tests. The apparatus is adapted for use in the monitoring of steam generators in fast neutron reactors.

Abstract: A vehicle able to move between two walls and particularly in the space between two vessels of a fast neutron reactor, for inspection and testing; the vehicle having two wheels bearing on one of the two walls and connected to the vehicle body by two longitudinal arms and two wheels bearing on the other wall and arranged symmetrically with respect to the previously mentioned wheels and connected to the vehicle body by two transverse arms. The longitudinal and transverse arms may be folded back to permit the passage of the assembly through an opening.

Abstract: The present invention is directed to a semi-automatic rod examination gauge for performing a large number of exacting measurements on radioactive fuel rods. The rod examination gauge performs various measurements underwater with remote controlled machinery of high reliability. The rod examination gauge includes instruments and a closed circuit television camera for measuring fuel rod length, free hanging bow measurement, diameter measurement, oxide thickness measurement, cladding defect examination, rod ovality measurement, wear mark depth and volume measurement, as well as visual examination. A control system is provided including a programmable logic controller and a computer for providing a programmed sequence of operations for the rod examination and collection of data.