Abstract: A system for inspection and mending in a reactor vessel of a nuclear reactor comprises a track mechanism, support mechanisms for supporting the track mechanism, an inspection apparatus traveling on the track mechanism, at least one mending apparatus traveling on the track mechanism, a setting mechanism for lowering all the above-described mechanisms and apparatus in the reactor vessel, each of which is composed so as to pass through a hole of an upper grid of a reactor, and an installing mechanism for positioning the support mechanisms fixed with two of the upper grid, a core support plate and internal structures below the core support plate and the track mechanism at the inside of the reactor vessel by remote control and for attaching the inspection apparatus and the mending apparatus to the same track mechanism by remote control.

Abstract: A system for mapping absolute acoustic noise intensity in a three-dimensional acoustic noise field, and using three-dimensional absolute noise intensities to infer operational or performance characteristics of components or structures within the monitored field. Localized noise sources are extracted using a distant array of transducers, and the absolute intensity can be measured even when totally masked by background noise at the transducer locations. The system includes an integrated sensor installation; a neural network detection system algorithm; a zoom system to precisely examine a small region in the steam generator vessel; a fuzzy logic system detection algorithm; and an expert detection system. The signal processing subsystem operates at three different levels of detection. At the top level of detection a trained neural network system monitors the vessel length for any indication of a leak. The proposed approach uses discriminators which do not require any beamforming of the sensor signals.

Abstract: A device for inspecting the support plates and tube sheet of a nuclear steam generator. The device comprises a boom for extending into an access port of a steam generator and into a lane separating two rows of members, the boom being uprightable within the lane; and a video camera attached to the boom for inspecting the tube members and support plates within the lane when the boom is uprighted. In a preferred embodiment the video camera comprises a charge coupled device affixed to a remotely controlled pan and tilt mechanism.

Abstract: An online system for diagnosing operability of a rotating electrical apparatus includes sensors producing electrical variables corresponding to operating conditions of the apparatus, data converters for converting the electrical variables to digital values, a comparator for comparing the values to corresponding predetermined baseline values of the apparatus and producing a corresponding comparison value, and a signalling mechanism for outputting signals related to a period of predicted operability of the apparatus whenever the comparison value exceeds a corresponding predetermined deadband value. The operating conditions may be non-electrical operating conditions, such as a condition of a lubrication system or a bearing of the apparatus. Alternatively, the sensors may sense electrical insulation non-thermal parameters during operation of the apparatus, in order to produce signals related to the operability of an insulator of the apparatus.

Abstract: A probe guide assembly permits optical inspection of critical nuclear reactor coolant pump motor parts located inside a generally cylindrical motor housing without requiring disassembly of the motor. The assembly is removably mounted to the outside of the housing near a vent and includes a probe guide member for carrying an elongated probe guide that extends into the housing through the vent. The probe guide member is mounted to a cross bar that spans the vent in a first direction. The probe guide member can be moved to a selected position in the first direction along a slot in the cross bar and can rotate in the slot so as to angularly position an end of the probe guide interior the housing. The cross bar is adjustably positioned in a second direction across the vent by fastening the ends of the cross bar to different points along a pair of mounting bars extending in the second direction on opposite sides of the vent.

Abstract: A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium.A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface.

Abstract: A method and an apparatus for measuring the degree of intergranular stress corrosion cracking protection in the area of the core shroud weldments. Electrochemical potential sensors are attached to the shroud wall and the upper core spray line at locations near the actual weld surface of concern to ensure the accuracy of the electrochemical potential measurements. A working electrode doped or coated with noble metal and a reference electrode are implanted into the reactor core shroud. A throughhole is drilled or machined into the shroud wall at an elevation just below the top guide support ring, i.e., near the core shroud weldments. Then a plug containing the working and reference electrodes is inserted into the throughhole.

Abstract: A method for mitigating crack initiation and propagation on the surface of metal components in a water-cooled nuclear reactor. An electrically insulating coating is applied on the surfaces of IGSCC-susceptible reactor components. The preferred electrically insulating material is yttria-stabilized zirconia. The presence of an electrically insulating coating on the surface of the metal components shifts the corrosion potential in the negative direction without the addition of hydrogen and in the absence of noble metal catalyst. Corrosion potentials .ltoreq.-0.5 V.sub.she can be achieved even at high oxidant concentrations and in the absence of hydrogen.

Abstract: An improved method for repair of incore-instrumentation-housing and related defects in a nuclear reactor system involves three stages, each with ultrasonically assisted inspections. In the first stage, a defective incore housing is removed and the exposed area and aperture at the former location of the incore housing is ultrasonically inspected using an ultrasonic probe with a tiltable disk-shaped head that self-conforms to the local contour of the reactor vessel bottom. In the second stage, a weld buildup is formed. The reactor is then sealed and the weld buildup is machined to define an aperture therethrough. The weld buildup is then ultrasonically inspected with a second probe with a centering member that is stationary as the probe body is moved vertically relative to it. In the third stage, a J-prep is formed. A new incore housing is inserted through the weld buildup aperture. The new incore housing is welded at the J-prep. The J-weld is ultrasonically inspected using a third ultrasonic probe.

Abstract: The invention provides an improved contamination inspecting device which can carry out continuous, automatic inspection of portable articles both large and small regardless of their shape. The device incorporates a conveying means for carrying the articles through the inspection position wherein the speed of the conveying means is varied based on the background radioactivity detected by the plane scintillator, a plane scintillator for detecting radiation from both the background environment and the articles to be inspected, a five-axes gate-type underriding mechanism which incorporates a robot arm so as to enable the plane scintillator to travel along the surfaces of each article, and control means for controlling the speed of the conveying means based on the background radioactivity detected by the plane scintillator and for controlling the five-axis robot based on the shape of the articles to be inspected.

Abstract: A device for easily installing and removing strain gauge instrumentation and associated wiring on the inside of in-core monitor housings. A vibration sensor is attached to an inside diameter of a cylindrical housing. A signal cable is coupled to the vibration sensor and extends into an exterior of the reactor pressure vessel. A protective assembly minimizes the damage inflicted on the signal cables during handling. The signal cables are helically wound in an annular space between a pair of concentric thin-walled tubes and then passed through cable penetration bores formed in the body of a flange insert. The flange insert supports the concentric tube assembly and is sandwiched between the housing flange and the in-core monitor instrument flange of a conventional in-core monitor assembly.

Abstract: In a method of inspecting heat exchanger tubes of a heat exchanger in which the heat exchanger tubes are fixed in position by spacers and serve to transfer heat from a first medium to a second medium that is fluid-tightly separated from the first medium, a measuring probe is introduced into an heat exchanger tube to be inspected. A wall section of the heat exchanger tube is subjected to an electromagnetic alternating field generated by the measuring probe resulting in local eddy currents within the subjected wall section. An eddy current sensor that is rotatable in the circumferential direction of the heat exchanger tube is guided in the longitudinal direction of the subjected wall section of the heat exchanger tube. A voltage signal induced by the eddy currents within the wall section is picked up with the eddy current sensor. The voltage signal varies locally as a function of the condition of the material of the wall section, the thickness of the wall section, and the presence of a spacer.

Abstract: The device includes a first tubular support (11) carrying on its outside surface means for fixing to a handling tool, a second tubular support (18) mounted coaxially inside the first support (11) for rotation about its axis. A flexible strip (55) carrying a monitoring probe at one of its ends is engaged in a slideway support carried by the second support (18) and including an end part (65) mounted to pivot about an axis which is perpendicular to the axis (25) of the second support (18). The strip (55) is moved translationally along the axial direction (25) by a conveyor bolt (53). The inside surface of the tubular piece (3) is monitored by moving the probe fixed to the end of the flexible strip (55) rotationally about the axis (25) and in axial translation, inside the annular space (8) between the sleeve (5) and the tubular piece (3).

Abstract: A method for ultrasonically inspecting a closely packed regular array of mutually parallel, uniformly sized and spaced rigid rods surrounded by a thin-walled metallic channel and immersed in a compressible medium. The method utilizes the properties of coherently scattered ultrasonic waves to identify rods which are defective, out of position or missing. A plane, monochromatic ultrasonic wave is transmitted toward the array of rods on one side thereof. Then an interference pattern produced on an opposing side of the array is detected. This interference pattern is the result of multiple scattering and diffraction of the plane ultrasonic wave during propagation through the array of rods. When the wavelength is comparable with the rod diameter and the rods are not too close together, scattering results in spatial relationships that produce an unusually large amount of wave penetration through the array in certain directions relative to the incident propagation vector.

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: A robotic sampling device (32) for cutting part of a tube wall (12) for sampling, containing a cutting head (36), a retrieval assembly (38) and a drive mechanism (40), is used to cut a window or hole (60) in the tube wall (12) and retrieve the tube wall sample (56), where the sample can be mounted onto a separate tube for testing the physical properties of the cut wall portion, and where a video probe (62) and the like can be passed through the window (60) to monitor conditions near the support plates (14) and tube sheets (16).

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: The checking device comprises a mast (10) extending vertically in its service position and centered in the central free space of the guide tube, a flat blade-shaped element (36) pivoting on the lower part of the mast (10), a sensor (42) rotating about a pin on an outer end (36a) of the blade-shaped element, and a device (39) for rotating and powering the sensor (42) and for gathering the measurement signals emitted by it (42).

Abstract: An inspection rabbit for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON.RTM.). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system.

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: A detection and inspection of cracks (135) on the internal surface of the adapter (2) is carried out, at least in a zone close to the weld for fastening the adapter (2), using remote inspection operations comprising at least one dye penetration inspection with remote borescope examination of the cracks (135) revealed by the dye penetration. At least one excavation cavity (136) is made by machining to a specified depth of the internal surface of the adapter (2) having a crack (135). As a function of the result of the dye penetration inspection, the zone is or is not built back up after excavation. The device comprises an assembly for moving a rod in translation and in rotation inside the adapter. Brushing, cleaning or sprinkling devices, a device for moving a borescope support inside the adapter and tooling for machining the internal surface of the adapter may be fastened to the end of the rod.

Abstract: Apparatus and method for radiographic inspection of welds, which welds may be seal welds of the kind typically found on nuclear power reactor control rod drive mechanisms (CRDMs). Such CRDM seal welds seal the threaded joint defined by a generally tubular pressure housing and a generally tubular vessel head adapter, the housing and adapter enclosing the CRDM components. The apparatus comprises a circular track capable of surrounding and being connected to the vessel head adapter. A radiation source assembly capable of emitting penetrating radiation and a radiation shielding assembly capable of shielding against the radiation are mounted on the track. The assemblies are adjustable for aligning the assemblies with the seal weld. A radiographic film is interposed between the radiation source assembly and the radiation shielding assembly and adjacent the weld for capturing a volumetric image of the weld on the film.

Abstract: An apparatus and a method for measuring and controlling the crack growth rate within a double cantilever beam type test specimen. The arms of the test specimen are fitted with a pressure-actuated bellows to induce a predetermined load and with a sensing assembly to provide feedback on the amount of beam displacement resulting from application of that load. In this manner a loaded test specimen may be remotely mounted and adjusted inside the reactor pressure vessel or piping of a nuclear reactor in order to maintain a stress intensity which is constant or which varies in a predetermined manner for inducing stress corrosion cracking or corrosion fatigue in the specimen.

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: Electrically controlled load activating mechanisms that can be used inside the containment vessel of a nuclear reactor in conjunction with bellows-loaded DCB crack growth sensors installed inside the reactor pressure vessel or piping of a nuclear reactor. One mechanism is a liquid-filled, double-bellows master/slave arrangement connected by a capillary tube to transmit the loading provided by a linear motion device. Another mechanism uses a heat-resistant gas bottle that can be heated in a furnace to increase the gas pressure to expand the bellows of the DCB sensor. A third mechanism uses a pump or compressor to provide the necessary expansion force. The loading is controlled via electrical connections that do not require special pressure boundary penetrations of the containment vessel.

Abstract: A testing device for load-testing of specimens (3) in a nuclear reactor environment is attached to one of the pipes (1) of the reactor for conveying a first medium under pressure and provides a first space (14) in open communication with the pipe (1). In the first space (14) a movable pull rod (15) is arranged, one end of which is attached to one half (16) of a specimen (3) arranged in the space (14). The other end of the pull rod (15) is joined to a tensile force device capable of being influenced by the first medium for achieving a tensile stress in the specimen (3).

Abstract: An improved method for examining fuel bundle spacers using fiber-optic visual inspection apparatus. A distal end of a fiber-optic scope having image and light guides is inserted through an upper tie plate and between the fuel rods of a fuel bundle assembly at the top thereof. The distal end of the scope is then lowered into the space between a group of spacer ferrules until a side aperture of the scope is at the elevation of the spacer spring to be inspected. Light is supplied to the light guide and redirected out the side aperture to a spot proximal to the field of view of the image guide. The distal end of the scope is rotated until the spacer spring to be inspected is visible through an ocular lens coupled to the image guide. The spring is visually inspected for defects by moving the scope to scan the spacer spring.

Abstract: The tank contains a liquid in which a radioactive element emitting gamma radiation is distributed substantially uniformly. A photon detector (15) is disposed in the vicinity of the external surface of a measurement, zone of the wall (12), a count is made of the photons emitted by the radioactive element distributed in the liquid (7), through the measurement zone of the wall (12), a number of photons determined by counting is compared with a reference number emitted by the radioactive element through a reference zone of the wall (12) and it is deduced therefrom whether or not a defect (8) is present in the measurement zone of the wall (12). The measurement device comprises a photon detector (15) disposed at one end of a collimator (16) made of heavy metal traversed by channels or windows (17).

Abstract: Previously when testing a connector penetration of a reactor pressure vessel lid, one assumed that an annular gap between the connector and the sleeve was concentric. However, tests have shown that in some lid structures a deflection of the connector took place after cooling to room temperature, which led to an eccentric configuration of the sleeve and the connector. In order to be able to completely test such annular gaps, a method and device for nondestructive testing of a penetration of a reactor pressure vessel lid according to the invention includes displacing the sleeve with the help of a thrust piece, until an accessible annular gap is reached. A sensor then arrives at the annular gap through a recess in the thrust piece.

Abstract: Previously, only webs between connectors in reactor pressure vessel lids have been examined for incipient cracks by using an ultrasonic scanning head. In order to be able to test the connector penetrated by a bush from an annular gap formed between the connector and the bush, a frame is provided which carries a housing through lockable floating bearings for receiving a rotary plate in the housing. The rotary plate is concentrically associated with a centering piece which is adjustable in the vertical direction and is eccentrically associated with a lifting cylinder which is likewise vertically adjustable. A free end of the lifting cylinder carries a probe drive for inserting a probe into the annular gap. The annular gap is scanned by the probe due to an oscillating movement of the rotary plate.

Abstract: Stress-corrosion damage is monitored in penetrations traversing the wall of a vessel containing an electrolyte, such as a nuclear reactor pressure vessel containing a coolant. The vessel wall has tubular penetrations for coupling external devices to internal structures of the vessel while maintaining a pressure barrier, such as control rod guides and sensor signal cables. The penetrations are subject to stress-corrosion damage, especially adjacent welds affixing the tubes to the vessel head. One or more of the penetrations is provided with a probe forming with the tube an electrochemical sensor cell, including an electrode exposed to the electrolyte together with the surface of the penetration. The electrode and the surface are otherwise insulated, and a plurality of electrodes can be arrayed for monitoring distinct localized areas.

Abstract: A method and system for electrochemically measuring the sensitization to stress corrosion cracking of small pipes of plant structural members in a very short period of time. A micro electrochemical cell for measuring the sensitization is movably disposed within a BWR plant ICM housing or an instrumentation pipe. An electrochemical instrumentation system for performing the electrochemical potential variation such as pulse voltammetry and a remote control system for remotely controlling the electrochemical cell are provided.

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 method and an apparatus for estimating the remaining service life of an object by measuring the physical quantity of a sample and which are applicable to a nuclear reactor. A plurality of model samples are experimentally prepared by preliminarily disposing a material having substantially the same composition as the object to be subjected to the estimation in an environment substantially the same as the object and measuring the physical quantities of the model samples in relation with exposure times. From this experiment, a relationship between the exposure time and the physical quantity under such an environment is obtained. Further, a critical exposure time which will cause an unstable fracture of a material of an actual sample, which is made of a material substantially the same as the object and placed in substantially the same environment as the object, is preliminarily obtained from the relationship between the exposure time and the physical quantity for the model samples.

Abstract: A device suited for inspecting selected positions of a nuclear power plant. The invention comprises a boom for extending to a position in a nuclear power station to be inspected, and a video camera affixed to the boom for permitting the visual inspection of the position to be inspected. In preferred embodiments, the video camera is affixed to a pan and tilt mechanism which may be adjusted by a remote joystick or by a control box situated on the boom. The video camera includes an auto-focus feature.

Abstract: The device comprises a central body carrying a first inflatable flexible head and two jacks each carrying an inflatable flexible head at its end. The rods of the jacks are oriented in two directions located on either side of the central body to assure displacement of the central body as a result of the retraction and extension of the rods of the jacks in opposite directions. In the expanded state, the inflatable flexible head are maintained by wedging in the annular space between the bundle casing and the outer casing of the steam generator. In the retracted and deflated state, the flexible heads can be displaced in the annular space. The device also comprises an assembly for guidance by rolling on the lower end of the bundle casing of the steam generator.

Abstract: A remote control apparatus for maintaining a tokamak type nuclear fusion reactor comprises a rail having a plurality of arcuated links to be extended in a circumferential direction and a plurality of joints for pivotally connecting the adjacent arcuated links, a vehicle running on the rail extended so as to form a continuous arc with its center substantially coinciding with the center of the torus space, and at least one handling device mounted on the vehicle, for handling the in-vessel components. The remote control apparatus is further provided with a rail housing device for receiving the arcuated links in a folded state when they are not in use, a rail mounting device for sending out said arcuated links in succession into the torus space, extending them so that they form a continuous arc and supporting the arcuated link on the proximal end of the rail, and a rail supporting device for supporting the central portion of the rail extended in the torus space.

Abstract: An improved method for repair of incore-instrumentation-housing and related defects in a nuclear reactor system involves three stages, each with ultrasonically assisted inspections. In the first stage, a defective incore housing is removed and the exposed area and aperture at the former location of the incore housing is ultrasonically inspected using an ultrasonic probe with a tiltable disk-shaped head that self-conforms to the local contour of the reactor vessel bottom. In the second stage, a weld buildup is formed. The reactor is then sealed and the weld buildup is machined to define an aperture therethrough. The weld buildup is then ultrasonically inspected with a second probe with a centering member that is stationary as the probe body is moved vertically relative to it. In the third stage, a J-prep is formed. A new incore housing is inserted through the weld buildup aperture. The new incore housing is welded at the J-prep. The J-weld is ultrasonically inspected using a third ultrasonic probe.

Abstract: A nuclear power plant includes a primary loop having a vessel with a connection piece. A manipulator for working in the vicinity of the connection piece, especially for non-destructive testing, includes two trolleys being moveable circumferentially of the connection piece. A jointed-shank arm disposed on the trolleys has two shanks each having first and second ends. Hinged supports are each disposed on a respective one of the trolleys and each support the first end of a respective one of the shanks. A crown hinge joins the second ends of the shanks together. A support for a tool or a test head is mounted on the crown hinge.

Abstract: An inspection device for the upper internals of a nuclear reactor comprising an elongated probe body which is lowered through a central aperture in a support plate that forms part of the upper internals and includes a plurality of vertically extending control rod apertures. Radial channels extend outwardly from the central aperture, each communicating with corresponding control rod apertures. A radially moveable transducer is mounted to the probe body and the latter is rotatable to a position for accessing each channel for radially moving the transducer into the channel. The transducer detects the profile of the channel. An area of particular interest is the area of communication between the channels and the control rod apertures. This area is susceptible to wear due to vibrations of the control rods.

Abstract: An especially designed probe carries preferably five transducers for the examination of a right circular cylinder flooded with water having limited vertical clearance from the point of required non destructive inspection. The probe includes a generally disc shaped body having a minimal vertical dimension and a radius slightly less than the radius of the right circular cylinder to be inspected. Insertion of the probe interior of the right circular cylinder occurs. At the periphery of the disc, there are disposed five interrogating acoustical transducers. These transducers are spaced from preselected staggered circumferential locations with respect to the right circular cylinder for examination of the water flooded cylinder with refracted rays.

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 track and carriage combination for supporting maintenance equipment in pressurized water reactor steam generators is disclosed. A pair of outwardly extending grooves are machined into the annulus portion of the generator tubesheet. Geared segments are provided for being inserted in the grooves for forming a geared track upon which the maintenance device may be firmly supported. Each geared segment includes gear teeth, a base shaped to mate with and engage the annulus grooves. A keyway is provided at the tubelane for allowing the segments to be slidably inserted into the grooves. Each segment is slightly curved so as to form a track corresponding with the annulus curvature. The segments are interlockable so that the segments may be removed from the annulus without any segments being left inside the steam generator. If desired, the track may be of one-piece construction and permanently mounted in the annulus.

Abstract: A robotic device for remotely inspecting pressurizer heater wells is provided which has the advantages of quickly, precisely, and reliably acquiring data at reasonable cost while also reducing radiation exposure of an operator. The device comprises a prober assembly including a probe which enters a heater well, gathers data regarding the condition of the heater well and transmits a signal carrying that data; a mounting device for mounting the probe assembly at the opening of the heater well so that the probe can enter the heater well; a first motor mounted on the mounting device for providing movement of the probe assembly in an axial direction; and a second motor mounted on the mounting device for providing rotation of the probe assembly. This arrangement enables full inspection of the heater well to be carried out.

Abstract: A removable platform comprises a chute (14) having a handling and fastening assembly (18, 19, 14a) at one of its ends and a supporting part (14b) in the form of a portion of a cylinder open laterally and extending the tube (14a) substantially in its axial direction, a supporting shaft (16) mounted in articulated manner at the end of the chute, an assembly of supporting arms (15) mounted for pivoting movement about the axis (29) of the supporting shaft (16) and a plurality of plane elements (17) resting on the supporting arms (15) in the unfolded position, to form a work platform substantially over the entire cross-section of the casing (2). The removable platform is introduced into the casing (2) in the folded-up state; the arms (15) form an assembly (30) seated in the chute (14), and the axis (20') at the supporting shaft (16) is substantially perpendicular to the longitudinal direction of the chute (14).

Abstract: In combination with a steam generator having a plurality of generator tube support plates, each generator tube support plate having a plurality of openings and a plurality of generator tubes, each tube passing through aligned openings in the support plates, a corrosion monitoring system is provided including a mockup probe, comprising a probe tube support plate having an upper side and a lower side and having substantially the same thickness and being constructed of substantially the same material as the generator tube support plates, having at least one opening of substantially the same size and shape as the openings of the generator tube support plates; at least one probe tube having an upper end and a lower end and having substantially the same diameter as the generator tubes and being constructed of substantially the same material as the generator tubes, the probe tube passing through the opening of the probe tube support plate; and wherein the mockup probe is adapted such that it may be inserted and seal

Abstract: A flexible, hose-like delivery system for positioning and rotatably supporting a probe which may be a pancake-type eddy current probe at a desired position along the longitudinal axis of a small-diametered conduit such as the heat exchanger tube in a nuclear steam generator is disclosed. The system comprises a flexible inner shaft formed from a plurality of short segments of Bowden shafting which is connected to a drive train located remotely from the interior of the heat exchanger tube, a flexible outer housing preferably formed from a plastic conduit concentrically disposed around the inner shaft, and a plurality of ball bearing assemblies which interconnect the short shaft segments for minimizing the frictional engagement between the inner shaft and the interior walls of the flexible outer housing.

Abstract: A flexible cable for carrying an inspection probe along the inside surface of a tube, such as a nuclear steam generator tube, to inspect the tube for anomalies and damage. The cable includes a core member having the inspection probe connected thereto and a plurality of adjacent interconnecting beads surrounding and disposed along the exterior of the core member. Each pair of adjacent beads defines a ball and socket joint for allowing the cable to flex without seizing or doubling-back on itself as the cable is moved in the tube so that the exact location of a tube anomaly can be precisely determined by measuring the length of the cable inserted into the tube.

Abstract: A remote control apparatus for maintaining a tokamak type nuclear fusion reactor comprises a rail having a plurality of arcuated links to be extended in a circumferential direction and a plurality of joints for pivotally connecting the adjacent arcuated links, a vehicle running on the rail extended so as to form a continuous arc with its center substantially coinciding with the center of the torus space, and at least one handling device mounted on the vehicle, for handling the in-vessel components. The remote control apparatus is further provided with a rail housing device for receiving the arcuated links in a folded state when they are not in use, a rail mounting device for sending out said arcuated links in succession into the torus space, extending them so that they form a continuous arc and supporting the arcuated link on the proximal end of the rail, and a rail supporting device for supporting the central portion of the rail extended in the torus space.

Abstract: An apparatus and method for monitoring corrosion to members within the core of a nuclear reactor, particularly fuel rod cladding. A sensor means is submerged inside the core of a nuclear reactor near the member or fuel rods. The sensor means is comprised of a generally cylindrical section having an outer surface that is subject to corrosion and radiation, and has a cross-sectional area A.sub.1. The sensor means additionally has a reference section subjected to radiation but not to corrosion, and having a cross-sectional area A.sub.2. At least one pair of first probes, separated by a length L.sub.1, is placed in electrical contact with the cylindrical section. At least one pair of second probes separated by a length L.sub.2, is placed in electrical contact with the reference section. A current is passed throughout the sensor means to produce a potential gradient in the cylindrical section and reference section.