Abstract: In order to reduce the time and difficulty of disassembling a seal arrangement which includes a Grayloc flange, in a cramped radioactive environment, the Grayloc hub is modified to include a step bore which receives a seal arrangement and a retaining nut which presses the seal into engagement with an inner wall portion of the hub and outer wall portion of an ICI (in core instrument) supporting column. A loading ring is threaded onto a portion of the column. Bolts associated with the ring are screwed down onto a belleville washer which is disposed between the loading ring and the top of the retaining nut for maintaining a desired amount of load on the seals irrespective of thermal variations.

Abstract: A steam line plug support tool for maintaining steam line plugs in steam line nozzles during the local leak rate test of boiling water reactors which includes an elongated beam with a support piece attached at a location to coincide with the steam line plug. The steam line plug support tool may optionally have a steam line plug attached to the support plate so that the support tool may be used for both installation and support.

Abstract: A process is claimed for reducing tensile welding stresses in a nozzle in a nuclear reactor shell, such as a nuclear reactor head, wherein the nozzle has been welded to the nuclear reactor shell, which involves applying axial compressive loads on the free ends of the nozzle in an amount sufficient to substantially reduce the welding stresses. In some cases radial pressure can be imposed on the inner wall of the nozzle wherein the tensile welding stresses are located.

Abstract: A plug assembly for plugging the flow hole of a core support barrel employs a pair of plug members which are initially collapsable to permit positioning between the core support barrel and the adjacent thermal shield. The plug assembly is activated to a projected plugged configuration by pneumatic or hydraulic pressure to provide a sealing engagement by a cooperative arrangement between circumferential locking barbs and a sealing lip.

Abstract: A sealing device for cylindrical hollow bodies of a small diameter has a cylindrical sealing insert with two coaxially arranged, axially displaceable members and an elastic sealing ring disposed between the two members. A displacement of the two coaxial members towards one another results in an enlargement of an outer diameter of the sealing ring and contact pressure between the outer circumference of the sealing ring and the inner wall surface of the hollow body. A remote-controlled placing tool is connectable to the sealing insert for clamping and locking the sealing insert in a sealing position and for releasing the sealing insert therefrom. The tool has a clamping cylinder with a clamping piston and a clamping piston rod in the form of a hollow cylinder connected to the clamping piston. A clamping anchor is connected to the first coaxial member and a sleeve is connected coaxially and axially slidable about the anchor. The tool is further provided with a release cylinder with a release piston.

Abstract: An apparatus and method for plugging an access hole in a steam generator, having a shell, a wrapper, and an annulus positioned between the shell and the wrapper, includes attaching a plate, having a first mating connection and at least one aperture, to the wrapper of the steam generator. A plug, having a second mating connection and at least one aperture, is positioned within a bore of the plate. The plug is rotated approximately 90.degree. for engaging the first mating connection of the plate with a second mating connection of the plug and for aligning the aperture of the plug with the aperture of the plate. A sleeve, having a bore therethrough and at least one aperture, is positioned on the plug and the aperture of the sleeve is aligned with the apertures of the plate and the plug. A pin is installed in the aligned apertures of the plate, the plug, and the sleeve. A retaining nut is positioned on the plug after installation of the sleeve.

Abstract: A plug assembly for plugging the flow hole of a core support barrel employs an offset arm for securing the plug to the core support barrel above the flow hole and the adjacent thermal shield. The disclosed embodiments do not require the cutting of an access opening through the thermal shield.

Abstract: A nozzle dam assembly for closing off a nozzle of a steam generator and a process for remotely positioning such nozzle dam are disclosed. The nozzle dam includes a mounting ring mounted on an inner surface of the steam generator about a periphery of an inner opening of the nozzle, at least one substantially planar central section and two substantially planar side sections together forming a substantially planar surface, the surface being of a greater diameter than the inner opening of the nozzle. Securing devices are also provided for securing each of the sections to the mounting ring after all the sections are positioned over the inner opening of the nozzle.

Abstract: Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening.

Abstract: Apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator. The invention includes an annular bracket sealingly attached to the rim of the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam that includes a first side section hingedly pivotably connected to a second side section for allowing the nozzle dam to be foldable. Removably connected to each side section is a center section, the center section and the side sections defining the generally circular nozzle dam for covering the opening defined by the annular bracket. The periphery portions of the center section and of the side sections have bores therethrough. A plurality of threaded bolts extend through the bores in the nozzle dam and into the threaded holes in the bracket for removably bolting the nozzle dam to the bracket.

Abstract: A plug and method for plugging a penetration in a pressure vessel wall having a sleeve protruding through the penetration. The sleeve is cut at a point between the interior and exterior surfaces of the pressure vessel wall. The cut portion of the sleeve extending beyond the exterior surface of the pressure vessel wall is removed. A plug sized to fit within the penetration is inserted into the penetration so that one end of the plug is flush with the exterior surface of the pressure vessel wall. A weld pad is deposited on the end of the plug and the exterior surface of the pressure vessel wall.

Abstract: A multisectioned nozzle dam (30) for use in a steam generator (24) with an integral bolt ring (32) has a body structure of general circular shape. Redundant seals including at least three separate inflatable peripheral seals (48, 50 and 52) with an alarm (A) for indicating a pressure increase between the second and third seals (50 and 52) is provided. Redundant supports including a plurality of independent bars (60, 62, 64 and 66) bolted to the integral bolt ring (36) secure the dam (30) within the nozzle (26) to the appropriate axial position.

Abstract: A hot pipeline is welded to a flange which is supported by brackets connected to a nozzle. The pipeline with a flange can expand freely radially. Welded to the other end of the flange is a pipe, which can withstand an axial temperature gradient between a temperature T.sub.1 at the pipeline and flange, and a temperature t.sub.2 at a compensator and the nozzle. The axial expansion of pipe is accommodated by the compensator, which is welded to the pipe and at its other end to the nozzle. The pipeline, the flange, the pipe and the compensator are subject to the difference between pressure p.sub.2 in the vessel and the pressure p.sub.1 in the pipeline.

Abstract: The device for pressure-sealed obturation comprises a flexible tubular casing (22) having an open end along the perimeter of which the casing constitutes an inflatable toric seal (30) and a base (22a) in the form of a glove finger on which there is fixed the end of a shaft (21) disposed at the central part of the casing (22). The shaft (21) passes through the base (22a) of the casing (22) in a sealed manner. The device also comprises a plate (38) for retaining the casing (22) comprising at least two parts articulated to one another as well as retention plate (41) for fixing the retaining plate (38) under the base (22a). Ring shaped elements (43) are retained against the toric seal (30) by an articulated spacing device (47).

Abstract: A system and method for installing a nozzle dam unit (26) in a nuclear steam generator having a head (12) including a head internal surface, a manway (14) penetrating the head, and a nozzle (16) penetrating the head. The system comprises a manipulator (76) adapted to be passed through the manway and having open end (82) adapted to be attached remotely to the head internal surface and a free end including a clamp member (104). A plurality of nozzle dam segments (54, 56, 58) are each sized to pass through the manway and carry means thereon (120) for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle. The manipulator is controlled so that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then is translated within the head until the dam subassembly seats within the nozzle.

Abstract: In a nozzle dam assembly wherein a circular dam faces into a nozzle adjacent its opening and a support frame abuts the backside of the dam and is removably affixed across a ring encircling the opening, apparatus for selectively locating the dam at its optimum sealing position within the nozzle notwithstanding the particular longitudinal profile of the nozzle or eccentricity of the ring-relative to the nozzle opening comprising apparatus for adjusting the dam relative to the frame along the nozzle axis and also vertically and horizontally perpendicular to the nozzle axis.

Abstract: The present invention relates to the construction and use of a device to compress biological parts (such as the abdomen), during the performance of interventional procedures (such as percutaneous biopsy), guided by cross sectional imaging procedures (such as computed tomography). The device is composed of a compressive surface with a hole. The compressive surface is constructed as part of a downward protruding member and lateral flanges or a rim, which can be attached, for example, to an abdomen, by means of a strap mechanism. An optional back plate can be used, such that a strap mechanism compresses the body part between the back plate and compression plate, or the compression plate alone can be place. The device can remain in place during cross sectional imaging, provided effective compression of the animal or human body part, yet access for percutaneous intervention is maintained by means of the hole in the compression surface.

Abstract: The present invention relates to a system, teaches a technique, and provides apparatus eminently useful for the installation/removal, from a remote and protected location, of nozzle dams onto and from nozzle holddown rings within the channel heads of certain steam generators, including the types typically used in conjunction with the operation of pressurized hot-water nuclear power plants.

Abstract: A disk of joined segments, having a water resistant sheet over the seams of joining, is mounted on a ring around the nozzle, and water tightly sealed against the ring by expandable rings. A circular portion of the disk that is concentric with the central axis of the nozzle is thinner than the central portion of the disk at the central axis of the nozzle, measured in solid cross section. The thinner circular portion is contoured for resistance to stress from pressure of fluid against the disk. The contour includes a concave annular outer surface of the disk, rising toward the center of the disk. At least one segment includes a beam oriented longitudinally with the segment, traversing and clearing the concave annular surface, and attached at each end to the segment. A plurality of bolt fasteners hold the disk to the segment. The bolt is threaded at the front end for screwing into the ring, and threaded at the back end for receiving a hold-down finger knob.

Abstract: A system and method for installing a nozzle dam unit (26) in a nuclear steam generator having a head (12) including a head internal surface, a manway (14) penetrating the head, and a nozzle (16) penetrating the head. The system comprises a manipulator (76) adapted to be passed through the manway and having one end (82) adapted to be attached remotely to the head internal surface and a free end including a clamp member (104). A plurality of nozzle dam segments (54, 56, 58) are each sized to pass through the manway and carry means thereon (120) for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle. The manipulator is controlled so that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then is translated within the head until the dam subassembly seats within the nozzle.

Abstract: A pneumatically actuated nozzle dam or the like for placement internally of a passageway, enabling the passageway to be sealed off upon inflation of a pneumatically inflatable ring. The apparatus includes an elastomeric diaphragm provided with sidewalls projecting in a downstream direction and joined with sealing flaps surrounding the sidewall and projecting back in an upstream direction. An inflatable pneumatic element is positioned between the sidewall and sealing flap and connected to only one of them. Upon inflation, the sealing flap is forced against the walls of the passageway to provide a seal. If depressurization of the inflatable element occurs, the sealing flap is retained in operative position by pressure of the retained body of liquid on the upstream side of the seal. The new arrangement eliminates the need for redundancy of the pneumatic element and, at the same time, provides for greater safety.

Abstract: A nuclear steam supply steam generator primary nozzle 16 is sealed by a nozzle dam having segmented bulkhead portions 42 and 45 with peripheral flanges 46,50,52. A rubber diaphragm with a body 54 and peripheral strata form oppositely opening cavities 56 and 58. Hydraulic pressure from either side enters one of the cavities to create a radial sealing force against the inside surface of nozzle 16. A closed cell foam rubber sealing material 76 of 20 to 30 durometer can be interposed between the cavity defining strata and the surface 16 to improve sealing. A hinged retaining ring 70 is pinned to hold the nozzle dam against radial surface 68 machined in nozzle 16.

Abstract: A sealing device is to be introduced through a manhole into a steam generator connected through a mouth of a connector to a pipeline with a restriction in the vicinity of the connector. The sealing device includes a plurality of serially disposed rubber hose seals defining an intermediate space therebetween to be pressure monitored. The rubber hose seals are subjected to to a pressure medium. Feed rollers guide the sealing device. A bracing device has radially outwardly movable clamping blocks and clamping angles. The clamping blocks may be moved outward. The clamping elbow may be axially fixed against the mouth of the connector for bracing the moved out clamping blocks against the restriction.

Abstract: A feedwater sparger assembly, and more particularly a thermal sleeve device, to prevent relatively cold feedwater from contacting the vulnerable surfaces of a feedwater nozzle in a boiling water nuclear reactor. Inner and outer concentric tubular thermal sleeve members (42,56) span the distance between the sparger (12) and a substantially cylindrical transition surface (34) machined into the feedwater nozzle (14) or pipe (22). At the first ends (46,64) of the tubular members, adjacent the transition surface (34), a packing means (50), is deformed against the transition surface (34). The second ends (60,62) of the tubular members are operatively connected to the sparger (12). One of the tubular members (42,56) is rigidly connected to the sparger (12) and the other tubular member is mounted on the sparger such that it can be longitudinally moved relative to the rigidly connected member.

Abstract: A joint between a pair of coaxial tubes which extend into a pressure vessel from a surface is sealed using a sleeve-like housing which surrounds the joint to be sealed. An upper fluid-tight seal is formed between the longer of the tubes and the housing. A lower fluid-tight seal is formed between the housing and the surface. An intermediate seal is also formed between the housing and the shorter tube. The upper and lower seals are independently preloaded through the use of spring washers. Primary loading of the lower seal to the surface is caused by fluid pressure in the vessel which acts on the housing.

Abstract: Apparatus for restraining the tip of a tube plug from traveling in a tubular member when the tip is fracturedly separated from the plug during the process of extracting the plug from the tubular member. The tube plug includes a shell defining an open cavity therein inwardly tapered from the tip of the plug. Slidably captured in the cavity is a shell expander which has a first bore therein, for expanding the shell into sealing engagement with the tubular member. The apparatus comprises an expansible restrainer, which is disposed in the first bore, for radially expanding the expander into engagement with the shell by radially expansibly engaging the first bore when axially compressed in the first bore. When the restrainer radially expansibly engages the first bore, the expander expansibly engages the shell for restraining the tip of the shell when the tip is fracturedly separated from the shell so that the tip does not travel in the tube and become lodged in or damage the tube.

Abstract: The shutter is composed of an assembly three independent panels comprising: a central panel (2) having a flange (6) for fastening to the orifice to be closed and having a seal and two rectilinear lateral rims (16, 18), and two side panels (1, 3), each comprising, on one part of its periphery, a flange (5, 7) for fastening on the periphery of the orifice to be closed, and which is provided with a seal, and, on the other part of its periphery, a rectilinear rim (12, 14) which forms a face for support on one of the lateral rims (16, 18) of the central panel (2) and on which are mounted members (20) for positioning the side panels (1, 3) on one of the lateral rims (16, 18) of the central panel.

Abstract: In a steam generator for a pressurized water type nuclear reactor, for the purpose of isolating a water chamber in the steam generator from a coolant piping communicating with the water chamber, a plug is disposed in a nozzle section of the coolant piping, the plug is supported by a support arm having an angle adjusting screw and fixedly secured to a mount seat at a manhole communicating with the water chamber, and preferably, a cover is provided on the mount seat at the manhole.

Abstract: A nuclear steam generator isolation dam (28) locking pin (36) is slidably mounted and spring (52) biased in an axial bore (42,44) of a body (40) press fit in a dam boss (32). The pin (36) is actuated by a lever (54) in a slot (54,58,62) for selective lock-in, lock-out and spring biased travel for seeking its keeper (27) in the wall (26) of the nozzle.

Abstract: A disassembleable and reassembleable sealing device for pipelines, includes a cylindrical sealing insert being insertable into a pipeline in a given direction, the sealing insert having a front cup part with a closed cross section and a rear ring part, as seen in the given insertion direction, the cup and ring parts being annular, coaxial and slideable into each other in axial direction of the sealing insert, the cup and ring parts having corresponding peripheral surfaces and ring shoulder surfaces at the outer periphery of the cup and ring parts defining at least one ring seat, at least one sealing ring inserted into the ring seat between the cup and ring parts, the sealing ring being bulged outward by deformation forces exerted on the sealing ring by the ring seat when the cup and ring parts slide toward each other, increasing the diameter of the sealing ring for pressing the sealing ring against the ring seat and forming a ring bead on the sealing ring resting against the inner periphery of the pipeline fo

Abstract: A system is provided for closing a conduit having a gripless inner surface, comprising a sealing wall and an annular seal disposed between the wall and the conduit. Beams connected to the wall by adjustable tie-rods, disposed bearing against the inlet end of the conduit, support and immobilize said sealing wall.

Abstract: The nuclear fuel element according to the invention comprises a can, which is sealed at its ends by plugs, whereof a cylindrical portion is force fitted into the can. The internal diameter of the can can vary between a maximum diameter and a minimum diameter, the diameter of the cylindrical portion being equal to said minimum diameter. Three serrations machined on the cylindrical portion form beads, whose thickness is equal to half the difference between the maximum diameter and the minimum diameter of the can.

Abstract: A nozzle dam for providing a fluid-tight seal across a primary fluid nozzle in the plenum of a nuclear steam generating vessel includes two fluid-impermeable seals, each comprising a circular three-section foldable seal plate covered with a flexible diaphragm and circumferentially encompassed by an inflatable seal member disposable in frictional sealing engagement with the inner surface of the nozzle. The center sections of the two seals are interconnected by tubular coupling means. The diaphragms are disposed on the high pressure sides of the seal plates, and the sections of each seal plate are hinged on the high pressure side. The center section of each seal plate carries two pairs of support tabs attached to the low pressure side thereof and respectively projecting from opposite ends thereof in cantilever fashion for supported engagement with a frustoconical portion of the inner surface of the nozzle.

Abstract: A retaining assembly holds a nozzle seal in the nozzle of a nuclear steam generator vessel. The assembly includes two arcuate beams generally following the curvature of the vessel wall, one beam lying generally alongside the divider plate and the other extending diametrically across the nozzle seal and being coupled thereto. The outer ends of the beams are anchored to the outer edge of the tube sheet and have brace members which bear against the vessel wall. The inner walls of the beams are interconnected by a thrust assembly which bears against the divider plate and includes an adjustable jacking screw means for urging the beams against the tube sheet. The effective length of the beam coupled to the nozzle seal can be varied by selectively replaceable spacers.

Abstract: A nozzle between the nuclear steam generator and nuclear reactor vessel has a dam, plug, or barrier mounted on the tapering internal wall of the conduit. A seating ring is mounted on the tapered internal surface of the nozzle through screws which will ensure release of the ring after pressure on the dam is removed, and the screws are backed away from engagement with the tapered surface.

Abstract: A hatch assembly has an annular seat, a hatch cover and a plurality of latching units. Each latching unit has a slidably supported locking bolt movable generally radially inwardly with respect to the annular seat into a hatch cover locking position and generally radially outwardly into a hatch cover releasing position. In the hatch cover locking position at least one length portion of the locking bolt extends over the hatch cover for maintaining the hatch cover on the annular seat. Each latching unit further has a rotary crankshaft, an operating handle torque-transmittingly connected to the crankshaft for applying a locking torque and an opposite, releasing torque thereto; and a coupling mechanism for connecting the crankshaft with the locking bolt and for converting rotary motion of the crankshaft to linear motion of the locking bolt. The coupling mechanism has a spring for transmitting the locking torque from the crankshaft as a radially inwardly oriented resilient force to the locking bolt.

Abstract: A nozzle dam for providing a fluid-tight seal across a primary fluid nozzle in the plenum of a nuclear steam generating vessel includes two fluid-impermeable seals, each comprising a circular three-section foldable seal plate covered with a flexible diaphragm and circumferentially encompassed by an inflatable seal member disposable in frictional sealing engagement with the inner surface of the nozzle. The two seal apparatuses are interconnected by a central tubular coupling coaxial with the nozzle and non-rotatably fixed to each seal, the coupling having a quick-disconnect feature operable from outside the nozzle dam. The coupling provides a conduit for inflation of one of the seals. The two seals are also interconnected by four post assemblies to maintain the seal plates parallel with each other, each post assembly including a cylindrical member pivotally movable between a release position and a supporting position, and provided with a slidable encompassing sleeve to lock it in the supporting position.

Abstract: In a nozzle dam assembly wherein a flange ring is affixed around a circular nozzle opening in a chamber wall, a support frame spans and is in non-threaded connection with the ring by releasable pins which carry under tension any load on the frame directed axially out of the nozzle into the chamber, and a circular dam with a sealing diaphragm disposed over it is attachable to the frame with its rim within the nozzle so that inflatable peripheral sealing means on the diaphragm effect the desired seal of the nozzle independent of the aforementioned axial load.

Abstract: A tool is insertable in the narrow annular access space between the cylindrical core barrel and the thermal shield of a nuclear reactor for testing and removing a plug from a flow hole in the core barrel. The tool includes two hydraulically driven jaws which have gripping flanges receivable in a peripheral groove in the plug head for gripping same. The jaws are thin plate-like members and each carries two short pistons having a length less than the thickness of the jaws and hydraulically extendable into engagement with the core barrel for exerting on the jaws and the gripped plug a predetermined force in a plug-removing direction. The jaws are preferably substantially coplanar and carried by a flat arm with the plane of the jaws disposed at a slight angle to the plane of the arm, which angle is selectively variable. Means are provided for pivotally moving the arm about an axis substantially parallel to the axis of the plug.

Abstract: An apparatus and method of sealing the cold leg nozzles of a reactor vessel during plant outages for reactor vessel inspection and core support maintenance includes insertion of a sealing plug into each of the cold leg nozzles, by means of an installation tool suspended within the vessel, to permit drainage of downstream piping and inspection and maintenance of associated steam generators and pumps.

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: The invention comprises a core barrel plug capable of being remotely installed in a port of a core barrel of a pressurized water nuclear reactor for converting the reactor from a by-pass downflow configuration to a by-pass upflow configuration. The plug comprises a body having an expandable cylindrical portion with a movable mandrel disposed in the body. Remote fluid pressurization causes the mandrel to be advanced thus expanding the body into contact with the port. The plug also comprises a locking mechanism to prevent inadvertent release of the plug.

Abstract: The plugs are used to close the main steam lines of a boiling-water reactor when the reactor is shut down for maintenance, testing and refueling. The plug utilizes an elongated rubber member which is compressed by axial compression in order to form a seal which will hold the plug in place despite the presence in the steam line of substantial isolation valve test pressures which might force the plug out. Preferably, plates covering portions of the rubber are used to provide a long-lasting solid surface to grip the inside wall of the pipe. A device is provided for the remote installation of the plug so as to minimize the exposure of workers to radioactivity in the reactor vessel. The installation device includes remotely controllable structure for compressing the rubber member of the plug. In one embodiment, the compression structure includes a set of impact wrenches for turning a nut on each of several bolts which are used to compress the rubber member of the plug.

Abstract: A stopper apparatus for use in blocking the unvalved nozzle of a cooling fluid filled nuclear reactor pressure vessel includes a plug, typically in the shape of a frusto-conical member having inflatable gaskets for sealing against a seat of generally unknown surface characteristics and means for positioning and urging the plug into position to seal the nozzle. The plug is typically positioned by suspension cables whereby the apparatus can be temporarily inserted and removed from the pressure vessel. The urging means is generally a two-way hydraulically driven jack controlled by remotely-actuated hydarulic lines. The apparatus is a tool which permits temporary sealing of a submerged outlet in a reactor vessel to permit maintenance on a fluid recirculation loop.

Abstract: A quick opening hatch for use on a transfer tube of a nuclear reactor plant that is adapted to replace the conventional hatch on the transfer tube. A locking ring is provided with a plurality of screw openings that is adapted for connection to the transfer tube, and a hatch cover fitably received within the locking ring for closing-off the transfer tube. To lock the cover to the ring, latches are movably connected with the cover for locking engagement with the locking ring, and a sprocket with a plurality of crank arms is movably connected with the cover and the latches for movement thereof into locking engagement with a latch housing on the locking ring for locking the cover to the ring and out of engagement with the latch housing for releasing the cover from the locking ring so as to permit removal of the hatch cover from the locking ring to provide access to the transfer tube.

Abstract: A removable plugging device for a pipeline, and particularly for pressure testing a steam pipeline in a boiling water reactor, wherein an inflatable annular sealing member seals off the pipeline and characterized by radially movable shoes for holding the plug in place, each shoe being pivotally mounted for self-adjusting engagement with even an out-of-round pipeline interior.

Abstract: There are disclosed method and apparatus for plugging the underwater recirculating nozzle of a boiling water reactor vessel. The method includes the lowering of a plug by a secondary cable into the annular space between the vessel sidewall and the nuclear fuel shroud. The cable is displaced outwardly, permitting the plug to enter the space between the sidewall and the jet pumps. Cable and plug are then shifted laterally into position over the nozzle, the weight of the plug being taken by a primary cable which lowers the plug into position. A special apparatus is provided which rests upon the core shroud and performs the steps of displacing and laterally shifting the cable.

Abstract: In this type of nozzle penetration, the nozzle (6) consists of a material different than that of the closure (1). In addition, closure (1) is provided with an inside plating. In order to avoid heat stresses on the tension coupling (15) between nozzle (6) and closure (1), a compensating ring (8) is provided between the shoulder (9) of nozzle (6) and contact surface (7) of closure (1). The height "h" of the compensating ring (8) and its material are selected in such a way that the change in elongation resulting from heat expansion of the nozzle and closure materials is compensated in the region of the distance extending from shoulder (9) to tension coupling (15). The material and height "h" can be selected in such a way that a predictable difference in stress is created in the area of the tension coupling upon heating.

Abstract: The present invention relates to a nuclear boiler comprising a vessel whose top is closed by a dismountable cover, a cage bearing the core of the reactor and separating the vessel into an inner hot zone and an outer cold zone, at least one steam generator disposed outside the vessel and comprising a tight enclosure, a tube plate, separating the enclosure into a primary part, or water box, and a secondary part, and bearing U-shaped tubes whose ends open into two concentric zones of the water box separated by an internal structure, at least one hot connecting pipe and one cold connecting pipe respectively connecting the hot zone and the cold zone of the vessel to each of the concentric zones of the water box, wherein the tube plate, the tubes and the secondary part of the enclosure of the steam generator define a sub-assembly dismountable from the primary part of the enclosure, the hot connecting pipe being dismountably mounted between the cage and the internal structure of the water box, this strucutre itself

Abstract: A method for sealing an object having a peripheral surface, surfaces substantially perpendicular to the peripheral surface and infinite enlongated bodies projecting from the surfaces perpendicular to the peripheral surface, which method comprises: wrapping the peripheral surface with a heat-shrinkable film in such a manner that both side edges of the film extend beyond the side edges of the peripheral surface; bonding longitudinal edges of the film to each other; and heating the heat-shrinkable film to permit the film to shrink to thereby seal the peripheral surface and a peripheral portion of the surfaces perpendicular to said peripheral surface, except said infinite elongated bodies.