Abstract: A machine for examining a nuclear reactor fuel assembly, having a flooring of elongated shape, a rotary container located on a support at one end of the flooring, two vertically arranged rigid structures each consisting of two parallel tubes, a latching mechanism for the fuel assembly, including a large and a small branch which are pivotable with respect to each other, a device for immobilizing the small branch relative to the large branch, a trolley that can be displaced along the flooring towards and away from the support and carries a vertical column along which a bracket with a carriage is movable on which a television system or the like for examining the fuel assembly may be mounted.

Abstract: A method for remotely measuring the level of a bulk material in a vessel, wherein the bulk material comprises loose particles, with adjoining particles defining interstices therebetween. Liquid is added to the vessel at a constant flow rate through a liquid inlet of the vessel, wherein the liquid progressively fills the interstices of the bulk material from the bottom of the vessel to the surface level of the bulk material. The liquid level indications of a level measuring device are monitored as a function of time. The level at which the rate of change of liquid level in the vessel decreases is determined. Such level represents the surface level of bulk material in the vessel.

Abstract: Both an apparatus and process for providing a coolant flow path in the top former plate of the core of a nuclear reactor are disclosed. The apparatus of the invention generally comprises an elongated tool support member having a tool mounting means for detachably mounting various tools in the vicinity of the top former plate, and a clamp assembly for securing and positioning the tool mounting means over the plate. The apparatus also includes an ultrasonic transducer (or probe) for measuring the thickness of the plate, a rotabroach device having a feed and drive assembly for driving a pilot drill bit and a rotabroach bit toward the top former plate, and a piercing tool for removing the slug formed by the rotabroach bit. In the process of the invention, an alternate coolant flow path is provided in the top former plate by boring a plurality of holes therethrough.

Abstract: The invention concerns a method and apparatus for eliminating leakage spaces between the partitions (1) surrounding the core of a pressurized water nuclear reactor, after it is brought into operation.Operations are carried out under water, during shutdown of the reactor. The defective joins (12) between the partitions (1) are identified. For each join, the partitions (1) are pierced, the hole inside a partition (1) is screw-threaded, the swarf is recovered, a screw with diametrical expansion is introduced and screwed into the hole and the screw is expanded by displacement of a rod in the longitudinal direction of the screw. Moving location, the operations are repeated for each defective join (12). The apparatus comprises a case (25) containing a drum (36) bearing tools for boring (54-65), screw-threading, and screwing, a cleaning tube and a punch for locking the screw.The invention is applicable to work on pressurized water nuclear reactors, after they have been brought into operation.

Abstract: In the upper internals storage pit of a containment building housing a pressurized water nuclear reactor, there is installed a three-coordinate positioning apparatus which has a frame-like, horizontally oriented base track enclosing an area designed to be occupied by any of the control rod clusters when lowered from the upper internals supported in the storage pit; a mechanism for supporting and vertically displacing the base track in the storage pit; a traversing track supported on the base track for back-and-forth displacement in a first horizontal direction; a mechanism for moving the traversing track in the first horizontal direction; and a carriage supported on the traversing track for back-and-forth displacements in a second horizontal direction perpendicular to the first horizontal direction. The carriage is adapted to receive thereon inspection equipment.

Abstract: A steam generator wrapper closure and a method of installing the same includes a plug member (108) which includes a large diameter portion (110) and a small diameter portion (112) with an annular shoulder portion (114) defined therebetween. A locking pawl (124) is rotatably mounted upon the plug (108) through means of its shaft (122). A pawl shaft extension rod (154) and a handle (150) are utilized to manipulate the pawl (124) and the plug (108) from a position external to the steam generator outer shell (16). The axis of the pawl shaft (122) is radially offset with repect to the axis of the plug (108), and the diametrical extent of the pawl (124) is less than that of the small diameter portion (112) of the plug (108).

Abstract: Manipulator for carrying out measurements, tests, inspections and repairs in an open-top reactor pressure vessel comprising a manipulator bridge movable along the auxiliary bridge a platform with a substructure disposed above the manipulator bridge a non-rotating boom supported by a bearing surface supported by the platform, the boom projecting into the pressure vessel, guide rails disposed over the entire length of the boom, a U-shaped channel disposed over the length of the boom a boom bearing including a cylindrical part on the substructure, two roller guides inside the cylindrical part, a retaining mechanism for the boom, a carriage including a sleeve tube enclosing the boom braced against the boom, rollers guiding the tube, a fixed support ring, a rotatable support ring, a supporting member supported about the carriage for equipment, drives for the supporting members a load lifting device moving the carriage along the boom including cable drums cables wound on the drums with a free end fastened to a brac

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 universal tool for the weld inspection of tubular objects such as reactor vessels is disclosed. The tool is constructed from an array of transducers mounted in groups for common inspection of a particular weld volume. The individual transducers, as well as the groups, are arranged in a compact assembly for minimizing the overall dimensions of the tool and its corresponding weight. The transducers are arranged in a manner which permits inspection of tubular objects having different radii of curvature and corresponding different diameters with a single tool without the need of having to individually adjust the orientation angles of the transducers.

Abstract: A repair device for removing an inner surface layer on a feed-water connector of a reactor pressure vessel received in a reactor housing having an assembly platform with a carriage displaceable thereon transversely to the reactor pressure vessel, the repair device includes centering means located at a lower end of a telescopically extensible upright tube suspended from the carriage for centering the lower end of the upright tube in the pressure vessel, the centering means having at least two outwardly swingable supports and a hydraulic system for swinging the two supports outwardly umbrella-like; a supporting frame for a feed rod also disposed at the lower end of the upright tube, the feed rod being horizontally self-supporting at an end thereof; a drive motor connected to the feed rod for rotating the feed-rod; means located at the self-supporting end of the feed rod for centrally fixing the self-supporting end in the feed-water connector of the reactor pressure vessel; and a horizontally displaceable turnin

Abstract: A device for checking bent tubes by means of a probe, such as a pneumatically propelled eddy-current probe. The device comprises a sealing-tight enclosure adapted to communicate with the tube to be checked via a connecting tube. The introduction pressure of the probe is produced by a pneumatic circuit. The probe comprises a checking head and a cable having floaters and is wound on a coil driven by a torque motor. The introduction speed of the probe is controlled by passing it over a drive pulley, to which it is permanently applied by a strap tensioned by a spring, the pulley being mounted on the shaft of a constant-speed motor. Application to the checking of the tubes of heat exchangers, condensers and steam generators, more particularly of nuclear reacters.

Abstract: A model steam generator including a system for facilitating the inspection of the sample tubes within the boiler vessel of the model generator is disclosed herein. The system includes means for detachably connecting the tubesheet from the primary and secondary sides of the boiler vessel. In the preferred embodiment, both end of the tubesheet and the abutting ends of the primary and secondary sides of the boiler vessel are circumscribed by tapered flanges. The tubesheet is detachably connected from the primary and secondary sides of the boiler vessel by means of Grayloc.RTM.-type annular clamps which are circumscribed by grooves for receiving the abutting flanges at the tubesheet joints. Additionally, the system includes a frame for suspending the secondary side of the boiler vessel, a wheeled cart having a jack for both laterally and vertically moving the primary side of the boiler vessel and the tubesheet into a clamping position onto the secondary side of the boiler vessel.

Abstract: An inspection and repair system for a substantially enclosed radioactive work environment to protect and shield workers therein from radiation. The system decreases health hazards for workers and increases the safety margin within the environment. The method contemplates utilizing a tank coupled to the environment for entrance thereto. The environment and the tank are filled with a radiation attenuating fluid which protects workers entering the environment through the tank. The workers are supplied with air from an external source for respiratory protection and relieving the worker of cumbersome self contained breathing apparatus. The system can also utilize pumps for circulating the water therein and a filter for filtering out contaminants.

Abstract: A machine for dismantling, unloading and transferring to a disposal facility, nuclear reactor structure and/or components, which have been irradiated during operation of the reactor. The machine includes in one example a gantry mounted on a rigid, undismantled part of the reactor such as rails on the refuelling level of the reactor, a carriage angularly movable on the gantry, a platform movable linearly on the carriage, a mast on and axially movable relative to the platform, a manipulator mounted on the mast for angular and linear movement relative thereto, a variety of tools selectively mountable on the manipulator for effecting dismantling of reactor structure and/or components, and hoist means movable along a beam rotatable about the reactor center line and alignable with other beams to allow transfer of the hoist means from one beam to another. Alternative arrangements for varying the elevation of the mast are also disclosed.

Abstract: A method and apparatus for servicing a nuclear reactor system is disclosed whereby a reactor vessel (10) filled with radioactive water from a refueling canal (16) and associated steam generator (30) and pump units (38) may be serviced simultaneously while the reactor is out for refueling. The apparatus includes a plug unit (A) and an installation assembly (B) for inserting a plurality of plug units into reactor vessel nozzles (40). Each plug unit (A) includes a radially expandable seal rings (50, 52) and secondary seal (58) carried by a tapered portion (56) which wedges the plug unit (A) into the nozzle (40) under hydrostatic pressure. Installation assembly (B) includes a pair of telescoping units (70) having a pair of telescoping arms (72) and (74) which moves axially in opposite directions to insert plug units (A) carried at the ends thereof into diametrically opposed nozzles. A brace (120) provides a reactionary force against which the nozzles may be pulled out in the case of difficulty.

Abstract: For the inspection of a reactor vessel (1) there is used a carriage (4) provided with wheels (15) to enable the carriage to be driven around a reactor opening (2). The carriage supports a mast (36), which is provided with inspection equipment (38) which can be driven along the mast. Known apparatus of this kind block the reactor opening, thereby to prevent other work from being carried out during an inspection period, for example such work as the change of fuel elements. According to the invention, the carriage with mast and inspection equipment are so formed that a geometric projection thereof onto a plane extending perpendicularly to the geometric axis of the cylindrical reactor vessel lies within a sector of less than 180.degree., with the exception of an area outside the geometric projection of the reactor hearth onto the same plane.

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: Apparatus for remotely controlled examination of the control rod drive penetration stub tubes in the wall of a nuclear reactor pressure vessel including a rotatable carriage on which is mounted a reciprocable shaft to which is attached an inspection instrument for scanning the stub tubes.

Abstract: A method and device for ultrasonically inspecting the corner region formed by the joining of a pair of cylindrical conduits is disclosed. Ultrasonic sound beams (62) are transmitted beneath inner surface (12) of the first conduit at an oblique angle resulting in a shallow refracted sound path (74) through the solid corner region (84). Sound energy (76) reflected by the presence of a radially oriented crack (67) within the desired zone of interest (66) passes (80) out of the solid (84) for detection. A device having an ultrasonic transmitter (44) and a directional receiver (60) is disclosed carrying out the inspection method according to the present invention.

Abstract: A method and apparatus are disclosed for carrying out repair, maintenance or testing of apparatus, components and the like in hot cells, more particularly hot cells of reprocessing plants for spent nuclear fuels. The position of damage zones is detected and ascertained with the use of coordinates. Replacement parts and tools are moved into the maintenance and work position in dependence upon the coordinate data, and the repair or maintenance work is automatically carried out under computer control, with remote operation and remote monitoring. For carrying out the work, computer-controlled handling machines and manipulators are used which are adapted to travel in controllable manner in the hot cell. The monitoring and detecting, using coordinates, of damage zones and defects may be carried out with the use of cameras and/or leak detectors.

Abstract: The lip of the inner radius of a nozzle mounted through the wall of a nuclear reactor vessel is sandwiched between a transmitter and receiver of ultrasonic sound. The transmitter scans the internal surface of the nozzle lip while maintained a constant average distance from a receiver scanning the nozzle surface on the reactor vessel side of the lip. The two surfaces intersecting to form the inner radius vary in angle as the surfaces are scanned by the transmitter and receiver. Linkage is shown between the transmitter/receiver and the boom with which they are caused to sweep the lip to simultaneously accommodate the saddle shape of the inner radius and the varying angle between the lip surfaces.

Abstract: A manipulator control system uses a microprocessor to compute appropriate control parameters in order to maintain constant tangential velocity of a spray nozzle in relation to the inside surface of a spherical portion of a nuclear steam generator. The microprocessor also computes, in one of the three modes of operation, of the control system, appropriate control parameters for maintaining a predetermined distance between the nozzle and the center of the spherical enclosure.

Abstract: A rail apparatus for running an automatic ultrasonic flaw detector around a reactor pressure vessel for detecting any flaw in the weld beads on the reactor pressure vessel. At least two circumferential rails and vertical rails are connected through turn tables at their crossing points to form a rail unit. The rail unit has vertical rails extending upward from the uppermost circumferential rail. The vertical rails are secured to a gamma shield, so that the rail unit as a whole is suspended from the gamma shield by means of these vertical rails. The rail unit is provided with swing prevention devices for preventing swing thereof. In installation of the rail apparatus, the rail unit is temporarily mounted on the reactor pressure vessel before mounting the latter in a containment vessel. Then, after accurately placing the reactor pressure vessel together with the rail unit in a right place within the containment vessel, the rail unit is supported suitably by the gamma shield.

Abstract: A wheeled transporter is placed at the periphery of the tube bundle which extends up from its tube sheet within a nuclear steam generator shell. The transporter is formed in hinged sections which can be disengaged as required at the periphery of the tube bundle. A cable attached to each end of the transporter extend through the handholes for movement of the transporter along the bundle periphery. Pistons on the transporter are controlled remotely to extend into engagement with the internal wall of the generator shell to selectively immobilize the transporter at any desired peripheral position and thereby form a steady base for maintenance and inspection devices mounted on the transporter.

Abstract: An ultrasonic transmitter (10) and at least two ultrasonic receivers (12, 16) are mounted on a carrier (18) which traverses the surface (22) of a solid material (24). The sound beam (30) from the transmitter (10) passes beneath the surface (22) and enters a zone of interest disposed about a point (36) located a fixed distance (40) beneath the surface (22). Reflected sound beams (42, 46) emanating from flaws (54, 58, 60) located within the zone of interest are detected by the receivers (12, 16). The orientation and positioning of the transmitter (10) and the receivers (12, 16) for maximizing the detection and differentiation of the detected flaws (54, 58, 60) are also disclosed.

Abstract: A rail apparatus positioned around the surface of a reactor pressure vessel surfaces (1) for carrying equipment such as a flaw detector to permit the equipment to move along the surface of a reactor pressure vessel in the vertical and circumferential directions. The rail apparatus has a plurality of vertical rails (81) and at least one circumferential rail (82) connected to the vertical rails through turn tables (83) at respective points of intersection. Each vertical rail (81) is supported by a supporting member wall fixed at its one end to a gamma-ray shielding wall (2) surrounding the reactor pressure vessel. The vertical and circumferential rails as a unit are retained by the gamma-ray shielding member (84) through oscillation prevention means (86).

Abstract: Reactor pressure vessel inspection apparatus which permits the non-destructive testing of the vessel lower head, shell and top flange taper areas without equipment modification. The inspection apparatus includes an articulated joint assembly which permits a transducer support arm to be rotated about three intersecting axes, the three axes defining two pair of transverse axes.

Abstract: An arrangement for inspecting a reactor vessel immersed in a water-filled tank (31) comprises a mast carriage which is arranged for movement around the opening of a reactor vessel and which has fixedly connected thereto a mast which carries a track means (10) on which inspection apparatus (19) can be driven. To render it unnecessary to lift the mast carriage and mast into the reactor hall when, for example, replacing inspection apparatus, there is arranged, in accordance with the invention, on the upper end (20) of the mast a docking unit (21) which is provided with a second track means (22) connecting with the first track means (10). A carriage supporting the inspection apparatus can be driven onto the second track means.

Abstract: Machine for monitoring internal equipment of a nuclear reactor, when stored outside the reactor vessel in the swimming pool of the reactor, comprising a first longitudinal carriage (16) movable on rails (14) on the bottom of the swimming pool, a transverse beam (46) movable on the first carriage (16), a second transverse carriage (61) bearing monitoring instruments (65) and movable on the beam (46), and an arrangement for moving the beam (46) in predetermined steps on the first carriage (16), and the second carriage (61) on the beam (46).

Abstract: A positioning and removal device for a checking means or a tool in a receiver installation, in a medium inaccessible to an operator. The device comprises a flexible guide track fixed to the receiver installation, a carriage movable over the track including a drive motor and a gear wheel, a loading sleeve fast to the carriage closed by a part and including a cam and a groove, a tool support unit provided with catches and an arrangement for hooking the support unit on a complementary arrangement borne by the installation. The forward movement of the carriage permits the opening of the hooking arrangement and hooking of the support unit onto the sleeve at the level of the groove by the catches, when the part is in out-of-service position. When the part is in service position on the sleeve, the forward movement of the carriage permits the transportation and hooking of the support unit of the tool to the receiver installation.

Abstract: A transducer, especially suitable for monitoring welds (22), in a sodium-cooled nuclear reactor, has two plates (11, 12) in sliding face contact with parallel slots (13, 14) holding inductively coupled conductors (15, 17). One plate (12) is connected directly to one side of the weld and the other plate (11) is connected via an arm (23) and spacer (24) to the other side of the weld. Multiple slots and conductors can be employed to remove ambiguity from measured signals from the transducer. Multiple transducers can be employed in a scanned X-Y matrix.

Abstract: An ultrasonic flaw detector for detecting any flaw existing in the inner peripheral corner section of the joint portion between the barrel of a nuclear reactor pressure vessel and each of a plurality of cylindrical nozzles projecting from the barrel, by means of an ultrasonic wave applied from the outer peripheral corner section of the joint portion. The flaw detector has a probe pivotable around an axis which is made to follow up the locus of the center of curvature in the rounded surface of the outer peripheral corner section during the movement of the probe around the nozzle. According to this arrangement, it is possible to achieve a full automatic and remote control of the flaw detector except the attaching and detaching of the same, and to facilitate the processing of the signals representing the result of the flaw detection.

Abstract: Apparatus is disclosed for decontaminating a nuclear reactor pressure vessel. It comprises a buoyant annular frame which descends into the vessel as the water level within it is lowered. Spray nozzles move around the frame on trolleys in a reciprocating fashion and spray water under high pressure on the inner surface of the vessel wall, resulting in automatic washdown of the reactor vessel.

Abstract: A support framework has casters which enable it to be moved into position for receiving the studs of nuclear reactor vessels so the studs may be cleaned and inspected. A housing on the framework isolates the stud while it is cleaned to control the radioactive debris removed from the stud surfaces. Brushes for the internal bore and external surface of the stud are mounted for simultaneously moving over the stud surfaces. Eddy current and ultrasonic inspection devices are substituted for the brushes and the internal and external surfaces simultaneously inspected while an encoder connected to both the inspection devices and stud manifest the location of any detected flaws.

Abstract: The invention relates to a protective device for the actuating mechanisms of the control clusters during tests under pressure of the primary circuit of a nuclear reactor. Before mounting the clusters, each guidance sheath for the parts connecting the clusters with the control mechanisms is provided with a removable filter dismountably fixed at the lower portion of the sheath. The filter is constituted by several metal gauzes. The invention is applicable to pressurized water nuclear reactors.

Abstract: Apparatus is disclosed for decontaminating the wall of a boiling water reactor cavity. A chassis on wheels is rollable on the refueling floor along the cavity curb. A pair of horizontal wheels roll against the curb. A support member extends upwardly and laterally from the chassis to clear the personnel handrail. A mast depends from the support member into the cavity and includes a horizontal reaction wheel bearing against the cavity wall. A vertically positionable carriage is mounted on the mast and carries water spray nozzles directed against the wall.

Abstract: A system for the remote visual inspection of an annulus defined between two vessels. A conduit member is disposed in the annulus having one end adjacent an upper portion of the vessel and the other end terminating adjacent an area to be inspected. The conduit member is provided with at least one aperture adjacent the area to be inspected and sized to receive a housing containing a camera and a light source. The housing and light source are introduced into the conduit member by a support means which includes at least a first hollow, flexible hose member having a first end connected to the housing and a second end terminating adjacent an upper portion of the vessels. The flexible hose member is made sufficiently rigid for introducing the housing through the conduit member by pressurization with a fluid. The system further includes a source of electrical power for the camera, a light, and display means for receiving signals from the camera as well as means for maintaining the camera at a desired temperature.

Abstract: A locomotion unit is remotely controlled to advance stepwise through a passageway by frictional engagement with the surfaces of the passageway walls. A support section is mounted on the locomotion device to bring special tools to bear at predetermined positions within the passageway to which the support is brought by the locomotion unit.

Abstract: A system for the remote visual inspection of a structure including two vessels, one disposed within the otherand defining an annulus therebetween. A guide member is provided circumferentially about an upper periphery of the two vessels. Mounted on the guide member are two motor-driven, diametrically opposed trolleys which support a flexible track member which extends downwardly through the annulus from one of the trolleys and back up the other side of the annulus to the other trolley. At least one motor-driven carrige is mounted on the track member and carries a camera and light source. By appropriate positioning of the trolleys and the carriage, all the surfaces of the vessels defining the annulus are accessible for visual inspection by the camera. In accordance with a particular preferred embodiment, markers are placed at preselected points in the annulus on one of the vessels to permit verification of the location of the camera and carriage.

Abstract: The baffle inspection apparatus comprises a gauging mechanism mounted on a movable support for determining the width of a gap between two adjacent baffle plates in a nuclear reactor. The gauging mechanism comprises a rotatable member with a plurality of feeler gauges disposed thereon that is capable of remotely rotating and laterally aligning each feeler gauge with the selected gap to determine the size of the gap. The apparatus may be equipped with underwater camera and lights for remotely viewing the inspection operation.

Abstract: The baffle maintenance apparatus comprises a peening apparatus mounted on a movable carriage for reducing the width of a gap between two adjacent baffle plates in a nuclear reactor. The peening apparatus comprises an hydraulic hammer mounted on a pivotable plate that is capable of being positioned in proper relationship to the baffle plate for reducing the gap therebetween. The baffle maintenance apparatus may also comprise a gauging mechanism mounted on the carriage for determining the width of the gap between the baffle plates.

Abstract: A nuclear power plant with a metallic, circulatory cooling loop formed with welding seams and including, as components thereof, a reactor pressure vessel, a heat consumer and a pump, as well as a coolant line connecting the components to one another, and thermal insulation provided on the cooling loop, the welding seams being testable by a track-traversing testing device, including a multiplicity of fixedly installed tracks having like profile and being associated, respectively, with welding seams on the components and the cooling line, at least part of the thermal insulation being in vicinity of the tracks and being formed as removable cassettes.

Abstract: An ultrasonic transducer apparatus and method for examining nuclear reactor jet pump beams for cracking. Examination is conducted in situ. An operator lowers a carriage portion of the apparatus into the reactor vessel with a pole. Ultrasonic signals are transmitted through suitable wiring from an external source to the transducer apparatus, which may employ a pitch-catch or pulse-echo mode of ultrasonic examination to test the beams. The carriage holds oppositely disposed pairs of ultrasonic transducers and positions them suitably near the beam to be examined in a proper orientation thereto. The mode of examination is selected by a switching mechanism. The apparatus includes a signal generator, receiver, and visual display.

Abstract: Apparatus for testing vessel walls having projections with a multiplicity of guide tracks extending among the projections for guiding a slide carrying a testing device, and carriage means for transposing the slide onto the individual guide tracks, the carriage means being movable on a transport track connecting the ends of the guide tracks, including a thrust hose rigid in tension and compression and guidable by the guide tracks, respectively, a drive for the thrust hose mounted on the carriage, the thrust hose connecting the slide to the drive, and a jib carried by the carriage and operatively associated with the drive, the jib being of such dimension as to accommodate the slide and the testing device and being movable for adjusting to the guide tracks.

Abstract: To monitor a nuclear fuel element or fuel elements located in a store, e.g. a pond in a swimming pool reactor, the store is illuminated ultrasonically using one or more transducers transmitting ultrasonic signals in one or more predetermined directions to obtain an output which, because it depends on the number and relative location of the fuel elements in the store, and the structure of the store itself is distinctive to the fuel elements or elements stored therein. From this distinctive output is derived an identity unique to the stored fuel element or elements and a reference signal indicative of the whole structure when intact, the reference signal and identity being recorded. Subsequent ultrasonic testing of the store and its contents under identical operating conditions produces a signal which is compared to the recorded reference signal and if different therefrom reveals the occurrence of tampering with the store and/or the fuel element or elements.

Abstract: A pneumatically operated pipe crawler for transporting inspection equipment along the interior of a pipe comprises an elongate cylindrical tube of flexible resilient material, such as latex rubber, the tube being partitioned by longitudinally spaced plugs which are hermetically sealed to the wall of the tube thus defining three longitudinally separated chambers. The inspection equipment is mounted at the leading end of the crawler. To advance the crawler along the pipe, air or other gas is supplied to the chambers and exhausted therefrom in repeated cyclic sequence for sequentially expanding the chamber wall portions into clamping relation with the pipe, each wall portion recovering to its axial length upon deflation of the chamber, thereby to propel the tube step by step along the pipe.

Abstract: Test equipment for the detection and analysis of material faults in a test piece, including a test head, an electrical remotely controlled manipulator for moving the test head in at least two degrees of freedom, a device connected to the test head for supplying the test head and evaluating signals thereof, a display connected to the test head for measuring test results thereof, a device for providing the manipulator with a testing program for automatically following a predetermined path at the surface of the test piece, an electronic transmission system connected to the manipulator, a device connected to the electronic transmission system for simulating the test piece, and a remote controlled hand-operated guide element disposed adjacent to the display in the simulating means for controlling the test head in correspondence to manual operation.

Abstract: A tool for manipulating an ultrasonic inspection transducer is actuated to move the transducer over the surface of an irregular weld body. The weld body disclosed, joins the nozzle of a reactor vessel to its vessel, the irregularity of the weld body defined by the intersection of the two cylinders. The transducer is moved over the surface of the weld body and actuated to scan through a predetermined angle in relation to the changing aspect of the geometry of the weld body by a cam mounted at the pivoting center of the tool.

Abstract: A system, suitable for use as an identity seal for an object, such as a container for fissile material, comprises a body including a cap for fitting over one end of the object, and a recess which contains a material such as "ARALDITE" or aluminium acting as a matrix for a plurality of inclusions of e.g. bronze embedded therein in a random configuration. The recess is closed by a cover which includes a central electrically conductive part. Also embedded in the matrix material and constituting further "inclusions" are two piezoelectric crystal transducers each electrically connected to the central cover part. In use, the transducers are electrically connected via the central cover part to external ultrasonic testing apparatus to provide a unique output indicative of the particular structure of the seal particularly the inclusion configuration and hence providing a unique "identity" and hence indication of integrity for the seal.

Abstract: An apparatus for thermally insulating nuclear reactor primary vessels. The apparatus includes a plurality of cylindrical reflective metal plates located within the primary vessel for thermally insulating the side walls of the vessel from the temperatures generated by the reactor. The reflective plates are radially spaced apart and are positioned in an annular inverted U-shaped chamber that traps inert gas around the reflective plates. The plates and the annular chamber insulate the side walls of the primary vessel from the temperatures generated by the reactor.