Abstract: A method of replacing a damaged thermal sleeve in a reactor vessel head adapter that connects a control rod drive mechanism to a reactor vessel head includes the steps of accessing the damaged thermal sleeve, removing the damaged thermal sleeve, and obtaining a replacement thermal sleeve having an elongated tubular body, a flanged region, and a plurality of slots defined in the elongated tubular body, each slot having a width which is sufficient to narrow a maximum outside diameter of the flanged region from a first diameter to a second diameter. The method further includes altering the maximum outside diameter of the flanged region on the replacement thermal sleeve, inserting the replacement thermal sleeve into an opening of a tubular member from an underside of the reactor vessel head, and expanding the maximum outside diameter of the flanged region into a recess of the reactor vessel head adapter.

Abstract: A method of using a pipe cap assembly for a normally-sealed system includes attaching the base portion of a pipe cap to a pipe of a normally sealed system. A transition cap having internal threads is releasably coupled to an externally-threaded cylindrical connector portion of the pipe cap for sealing the same during normal operation. When access to the normally sealed system is required, the transition cap is unthreaded from the pipe cap, and a transition fitting is installed instead. A drain hose, vent hose, or the like, may be coupled to an access port of the transition fitting and fastened thereto for passing fluids to or from the normally sealed system. Alternatively, a test instrument may be coupled to the access port. Thereafter, the transition fitting is removed, and the transition cap is re-installed.

Abstract: [Problem] To facilitate mounting of a nozzle. [Solving Means] In a nozzle mounting structure for mounting a nozzle 20 penetrating through a reactor vessel 10 having a hemispherical concave inner surface, the nozzle mounting structure includes a removed concave portion 17 in which a base material 12 on an inner surface side of the reactor vessel 10 is removed in a symmetrical shape around a normal line N on the hemispherical concave inner surface of the reactor vessel 10, a flange 25 provided on the nozzle 20, formed in a same symmetrical shape as that of the removed concave portion 17 around the normal line N, and inserted into the removed concave portion 17, and a weld part 18 provided around the normal line N for welding the flange 25 to the reactor vessel 10.

Abstract: A pressure vessel, including: a body portion; and an inclined nozzle projecting from the body portion along an axis inclined relative to an inner surface of the body portion, wherein: a through hole of a circular section is formed through both the body portion and the inclined nozzle. At an intersecting portion between the inner surface of the body portion and a surface surrounding the through hole, there are formed round portions. The radius of each of the round portions at two positions in a major axis direction is smaller than the radius of each of round portions.

Abstract: The invention relates to a plug device for jet pumps installed in nuclear power plant vessels, which comprises two covers (1-2) that form two independent plug units, one fitted on the even pump, which incorporates two plugs (6), and the other on the odd pump of each jet pump assembly, which incorporates three plugs (6), both mounted on a common base (3) at the end of respective arms (4), articulated in the central area, which are actuated by mechanical or hydropneumatic means. The plugs may be blind, in which case they are used to seal the five outlets of the nozzle of the jet pump, or channeled, being used to close the decontamination circuit of the recirculation loops, preventing the cleaning solution from being dispersed in the reactor.

Abstract: A support clamp assembly for mechanically securing a thermal sleeve to an elbow conduit in a jet pump of a nuclear reactor vessel, the support clamp assembly including: a tension shaft having a first end extendable through an opening in a sidewall of the elbow conduit and an opposite end with a head; a cruciform assembly having a base with an opening to receive the tension shaft and to abut the head of the shaft, wherein the cruciform assembly seats in the thermal sleeve; a boss slidable over the first end of the tension shaft and having a curved surface seating an outside surface of the elbow conduit, and a coupling device engaging the first end of the tension shaft and abutting the boss, wherein the coupling device places the tension shaft under tension to secure the cruciform assembly to the thermal sleeve and the boss to the elbow conduit.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump inlet-mixer integral slip joint clamp to constrain the inlet mixer and diffuser to mitigate inlet mixer flow induced vibration of a BWR jet pump assembly. The slip joint clamp includes horizontally projecting flanges with vertical sidewalls that protrude toward a lowest distal end of the inlet mixer. Fasteners penetrating the flanges provide a biasing load on the diffusers by being tightened to press against an upper crown on the diffuser. One or more flanges may be used. Laterally disposed gaps between the flanges may provide a clearance for guide ears of the diffuser to fit between the flanges.

Abstract: A core spray sparger T-box clamp for a sparger T-box in a shroud of a nuclear reactor pressure vessel, the sparger T-box clamp including: an anchor plate substantially aligned with a closed end of the T-box; a carrier plate slidably secured to an upper side the anchor plate and latched to the T-box; a saddle bracket secured to a lower side of the anchor plate and latched to the T-box, and a pair of clamp blocks on opposite sides of the anchor plate fixed to sparger pipes coupled to the T-box.

Abstract: Example embodiments are directed to core spray sparger T-box repairs, specifically, to universal core spray sparger T-box weldless clamps having remote-friendly operation and methods of using universal core spray sparger T-box weldless clamps. Example embodiment clamps may be secured without welding to a variety of upper and lower sparger T-box configurations. Example embodiment clamps may be configured to simultaneously engage a sparger T-box in multiple dimensions to allow a universal fit. Further, example embodiment clamps may be accessed, installed, or removed by interacting only with a front side of the example embodiment clamps, thus potentially reducing difficulty and cost in remote access repairs to example clamps.

Abstract: The present invention includes an apparatus for watertight sealing of a steam generator nozzle and methods for installing the apparatus. The apparatus comprises a nozzle dam, a nozzle dam attachment ring, and a seal. The attachment ring is provided in an interior of the nozzle and has a plurality of retaining tabs and a nozzle dam landing. The nozzle dam is adapted for insertion into the attachment ring and abutment against the nozzle dam landing. The nozzle dam has a plurality of radial protrusions adapted to interlock with the retaining tabs for fixing the nozzle dam in the attachment ring upon rotation of the nozzle dam in the attachment ring. The seal covers at least one side of the nozzle dam for effecting a seal between the nozzle dam and the attachment ring. The present invention also provides methods and apparatus for the pressurization and control of nozzle dam seals.

Abstract: [Problem] To facilitate mounting of a nozzle. [Solving Means] In a nozzle mounting structure for mounting a nozzle 20 penetrating through a reactor vessel 10 having a hemispherical concave inner surface, the nozzle mounting structure includes a removed concave portion 17 in which a base material 12 on an inner surface side of the reactor vessel 10 is removed in a symmetrical shape around a normal line N on the hemispherical concave inner surface of the reactor vessel 10, a flange 25 provided on the nozzle 20, formed in a same symmetrical shape as that of the removed concave portion 17 around the normal line N, and inserted into the removed concave portion 17, and a weld part 18 provided around the normal line N for welding the flange 25 to the reactor vessel 10.

Abstract: The invention relates to a plug device for jet pumps installed in nuclear power plant vessels, which comprises two covers (1-2) that form two independent plug units, one fitted on the even pump, which incorporates two plugs (6), and the other on the odd pump of each jet pump assembly, which incorporates three plugs (6), both mounted on a common base (3) at the end of respective arms (4), articulated in the central area, which are actuated by mechanical or hydropneumatic means. The plugs may be blind, in which case they are used to seal the five outlets of the nozzle of the jet pump, or channeled, being used to close the decontamination circuit of the recirculation loops, preventing the cleaning solution from being dispersed in the reactor.

Abstract: A core spray sparger T-box attachment assembly for a nuclear reactor pressure vessel, wherein the pressure vessel includes a shroud, a sparger T-box penetrating the shroud, a plurality of sparger distribution header pipes coupled to the sparger T-box, and a downcomer pipe. The sparger header pipes may include at least one sparger nozzle, and the sparger T-box attachment assembly may include a downcomer pipe coupling and a sparger T-box clamp. The sparger T-box clamp may include an anchor plate having a draw bolt opening to receive a draw bolt, a first clamp block substantially aligned at one end of the anchor plate, and a second clamp block substantially aligned at the other end of the anchor plate.

Abstract: A core spray T-box attachment assembly for a core spray nozzle includes a primary cruciform wedge and a secondary cruciform wedge in contact with the primary cruciform wedge to form a cruciform wedge subassembly adapted for insertion within a bore of the core spray nozzle to sealingly engage an interior converging portion of a safe end of the core spray nozzle. The assembly includes a spider in contact with the cruciform wedge subassembly, and a draw bolt engaging an axial bore of a center portion of the cruciform wedge subassembly and the spider to the T-box.

Abstract: A method and apparatus is disclosed for smoothly inserting a fuel rod loader through the skeleton of a fuel cell and then for pulling an attached fuel rod into the fuel rod skeleton while keeping the fuel rod under constant tension and preventing the bowing of the fuel rod. The pulling mechanism comprises a smooth collet with a smooth bullet end cap for guiding the puller mechanism into and through the skeleton where the bullet end cap is removed and the fuel rod is attached with a unique ball and slide mechanism actuated by a long puller rod that grabs the end of the fuel rod by a forward motion of the puller rod and is easily removed from the fuel rod by reversing this motion once the fuel rod is in place.

Abstract: A seal arrangement for providing a seal between a nuclear reactor in-core instrument housing and an instrument contained within the housing includes a lower seal assembly surrounding an outer portion of the in-core instrument housing, an upper seal assembly surrounding an outer portion of the in-core instrument, a seal housing enclosing the lower and upper seal assemblies, and lower and upper compression assemblies positioned on respective ends of the seal housing. The compression assemblies each include a drive nut and a compression collar. The compression collars engage and apply an axial load on the seal assemblies to maintain a reliable seal between the seal housing and the outer portion of the in-core instrument housing, and between the seal housing and the outer portion of the in-core instrument.

Abstract: A device for sealing a tube in an opening which is located in a component. The tube is in particular a lance shaft and the component is in particular a nozzle connected to a cover of a reactor pressure vessel. A pressure element is in operative connection with the tube. As a result, the tube is pressed against the component. Provision is made for the pressure element to be driven hydraulically.

Abstract: The present invention is used to reduce thermal load itself, being the cause to generate stress, which develops near liquid surface in a nuclear reactor wall and to contribute to further improvement of safety. A partition member (5) is arranged above a coolant liquid surface (9) in an annulus space (3) between a reactor vessel (1) and a guard vessel (2), a low-temperature gas is circulated through the annulus space above the partition member to cool down, the gas is circulated through the annulus space from under the coolant liquid surface to the partition member, and the high-temperature gas heated under the coolant liquid surface is used to raise the temperature above the coolant liquid surface.

Abstract: A seal arrangement for providing a seal between a nuclear reactor in-core instrument housing and an instrument contained within the housing includes a lower seal assembly surrounding an outer portion of the in-core instrument housing, an upper seal assembly surrounding an outer portion of the in-core instrument, a seal housing enclosing the lower and upper seal assemblies, and lower and upper compression assemblies positioned on respective ends of the seal housing. The compression assemblies each include a drive nut and a compression collar. The compression collars engage and apply an axial load on the seal assemblies to maintain a reliable seal between the seal housing and the outer portion of the in-core instrument housing, and between the seal housing and the outer portion of the in-core instrument.

Abstract: A seal arrangement for providing a seal between a nuclear reactor in-core instrument housing and an instrument contained within the housing includes a lower seal assembly surrounding an outer portion of the in-core instrument housing, an upper seal assembly surrounding an outer portion of the in-core instrument, a seal housing enclosing the lower and upper seal assemblies, and lower and upper compression assemblies positioned on respective ends of the seal housing. The compression assemblies each include a drive nut and a compression collar. The compression collars engage and apply an axial load on the seal assemblies to maintain a reliable seal between the seal housing and the outer portion of the in-core instrument housing, and between the seal housing and the outer portion of the in-core instrument.

Abstract: A seal arrangement for providing a seal between a nuclear reactor in-core instrument housing and an instrument contained within the housing includes a lower seal assembly surrounding an outer portion of the in-core instrument housing, an upper seal assembly surrounding an outer portion of the in-core instrument, a seal housing enclosing the lower and upper seal assemblies, and lower and upper compression assemblies positioned on respective ends of the seal housing. The compression assemblies each include a drive nut and a compression collar. The compression collars engage and apply an axial load on the seal assemblies to maintain a reliable seal between the seal housing and the outer portion of the in-core instrument housing, and between the seal housing and the outer portion of the in-core instrument.

Abstract: A reactor pressure vessel (RPV) for a nuclear reactor that permits measurement of the flow through each reactor internal pump (RIP) is described. The reactor pressure vessel also includes at least one reactor internal pump that includes an impeller and a pump diffuser. At least two seal rings extend circumferentially around an outer surface of the diffuser housing outer wall and are located in circumferential grooves in the housing outer wall. At least one lateral bore extends through the housing outer wall into a diffuser housing longitudinal flow passage. Each lateral bore is located in an area between two adjacent seal rings, with each inter-seal ring area containing one lateral bore. At least one pressure tap bore extends from the outer surface of the RPV bottom head petal, through the pump deck to an inner surface of a pump deck opening. Each pressure tap bore is aligned with an area in the RIP containing a corresponding lateral bore.

Abstract: A T-box assembly includes a T-box housing, a thermal sleeve coupled to the T-box housing, a cruciform wedge, a spider threadedly engaging the thermal sleeve, and a draw bolt coupling the cruciform wedge and the spider. At least one spring washer is located between the end of the thermal sleeve and the end of a core spray nozzle safe end. The T-box housing includes a cover opening having a plurality of breach lock lugs extending into the cover opening. A T-box cover plate includes a head portion and an insertion portion. A plurality of breach lock lugs extend from the periphery of the insertion portion. A plurality of ratchet teeth extend around the periphery of the head portion. A lock spring includes an engagement portion having a plurality of ratchet teeth sized to mesh with cover plate ratchet teeth.

Abstract: A locking device for a reactor instrumentation protective sleeve and reactor instrumentation column assembly. The locking device includes a protective sleeve coupled to the instrumentation column by a selectively operable and closeable clip assembly. The locking device also includes a locking sleeve supported by the protective sleeve. The locking sleeve is supported by the protective sleeve such that a portion of the locking sleeve covers a portion of the protective sleeve and the clip assembly.

Abstract: A clamp assembly prevents separation of a thermal sleeve penetrating a nuclear reactor pressure vessel wall and a jet pump riser elbow welded one to the other and lying within an annular space between the pressure vessel wall and core shroud. The clamp assembly includes a pair of heads having semi-cylindrical recesses. Pins project inwardly from each of the heads in the semi-cylindrical recesses and have axes which lie parallel to one another. By using actuators mounting multiple electrodes, holes may be formed in situ in the adjoining ends of the thermal sleeve and elbow. Once the holes are formed, the heads can be applied in situ with the pins being received through the holes and the heads clamped to one another. Thug, the pins in each of the sleeve and elbow prevent separating movement of the sleeve and elbow in the event of failure of the welded joint therebetween.

Abstract: A target grid assembly for employment in a target assembly used to produce radioisotopes by bombarding a target material contained in the target assembly with a particle beam. The target assembly includes the target grid assembly, the target window and a target body enclosed in a target housing. The target body defines a target reservoir for receiving the target material and the target window serves to seal the target reservoir. The target grid assembly includes a vacuum window and a target grid. The target grid defines a target grid portion, a helium input and a helium output. The target grid portion defines a plurality of target grid supports which are configured to form a plurality of target grid oblong openings. The vacuum window is supported against the upstream side of the target grid portion and the target window is supported between the downstream side and the target body.

Abstract: A T-box/thermal sleeve assembly replaces a damaged T-box/thermal sleeve in a core spray nozzle of a nuclear reactor. To replace the parts, the T-box and a portion of the extant thermal sleeve are removed from a location within the reactor vessel wall. The end of the thermal sleeve remnant is smoothed and a groove is formed along its interior surface. A replacement T-box/thermal sleeve and collet assembly are inserted into the nozzle bore from the interior of the vessel wall. The collet has axially projecting fingers with radial flanges for engaging in the groove to form a mechanical connection between the thermal sleeve remnant and the T-box/thermal sleeve replacement. A Belleville spring washer is interposed between the assembly and thermal sleeve remnant to place both parts in compression. A retention sleeve is screwthreaded within the replacement thermal sleeve to lock the fingers from radial movement.

Abstract: A T-box assembly to facilitate attaching a core spray line to a reactor core spray nozzle safe end without welding is described. In one embodiment, the T-box assembly includes a T-box housing, a cruciform wedge, and a draw bolt. The T-box housing is configured to be positioned so that a first end is located inside a core spray nozzle and engages the core spray nozzle safe end. Two other ends are configured to be in substantial alignment and configured to couple to core spray line header pipes. The T-box housing also includes a cover opening configured to receive a T-box cover plate. The T-box cover plate includes a draw bolt opening configured to receive the draw bolt. The first end of the T-box also includes a plurality of positioning lugs configured to engage the core spray nozzle to center the T-box housing in the nozzle bore. The cruciform wedge includes four web members extending from a central member and configured so as to form an X shaped configuration.

Abstract: An integral stub tube which simplifies the reactor pressure vessel fabrication process, provides a structural transition between the penetration and head, and facilitates future remote inspection of the attachment weld is described. In one embodiment, a stub tube is machined into the bottom head dome. Specifically, a penetration is formed in the bottom head dome by a bore having a stub tube portion. The stub tube portion has a cylindrical shape and a length of the stub tube portion is selected to provide a transition between a penetration housing and an adjacent portion of bottom head dome. The penetration housing extends through the penetration, in the dome. A weld attaches the stub tube portion to the penetration housing.

Abstract: A canopy seal clamp assembly (40) for stopping leaking in a canopy seal weld (42) located between a nuclear reactor vessel nozzle (30) and an elongated housing (24) includes an upper plate (44) having a central aperture (50) and an inner flange (52) spaced apart from a lower plate (60) having a central aperture (66) and an inner flange (68), a seal carrier (70) located adjacent the lower plate carriers a seal (72) for contacting an outer surface of a leaking weld (42) and connector (56) between the upper and lower plate maintain a compressive load to tightly seal the leaking weld and the compressive load tends to close and arrest further crack propagation in the weld. A method for repairing a weld is also described.

Abstract: A top mount canopy seal mechanical clamp assembly 20 for repair of a leaking canopy seal weld 16 between a nuclear reactor head penetration nozzle 12 and a mating part 14 has an annular housing 24 with insert support halves 28 and 30 for surrounding the nozzle. A top plate 34 is urged toward the support halves and housing by Belleville washers mounted on cap screws 42 threaded in bores 44 of the housing. A flexible graphite seal annulus 22 is compressed by the clamping action against the canopy seal weld 16 to create a flexible graphite leak stopping seal at the weld.

Abstract: For nozzle replacement, repair and initial installation in ASME pressure vessels, disclosed are nozzles, nozzle assemblies and nozzle repair assemblies, all of which are mechanically attached and mechanically sealed to the vessel, i.e., without any welding to the vessel, and in most embodiments without any welding at all. For nozzle replacement, a part or the entire existing nozzle is removed and a partial or full replacement nozzle or nozzle assembly is mechanically attached and mechanically sealed to the vessel. For nozzle repair, the existing nozzle within the bore is not removed, and a mechanical seal is provided for the existing nozzle which may also be welded or mechanically attached to the repair assembly.

Abstract: A coolant pipe blocking device for use in a nuclear power plant is provided to temporarily choke up a coolant inlet pipe to thereby inhibit fluid communication between a reactor and a steam generator, the steam generator having a coolant chamber in communication with the reactor via the coolant inlet pipe and a manway providing access to the coolant chamber. The pipe blocking device includes a plurality of hub segments(42-48) arranged along a longitudinal axis substantially with a uniform spacing to one another and an elongated, flexible, support rod(50) extending in a coaxial relationship with the longitudinal axis for interconnecting and keeping spaced apart the hub segments. A plurality of bladders(52-60) are arranged in an end-to-end relationship with respect to one another and attached to the hub segments to define a series of hermetically sealed air chambers.

Abstract: A nuclear reactor vessel has a nozzle plug in its cold leg and hot leg nozzles for isolating the reactor vessel from the balance of the reactor coolant loop. The nozzle plug is mechanically compression fitted with the nozzle without the need for hydraulic or pneumatic actuation. The plug has a primary seal ring compressed against the inner wall of the nozzle and a secondary seal ring compressed against the end wall of the nozzle for withstanding a pressure differential of about 34 feet of water.

Abstract: A sealing device comprising a supporting assembly (9) containing sealing members (16) supporting the instrument column (5), and an assembly (17, 18) for lifting the instrument column (5) in sealing engagement with the supporting members (16). The sealing members (16) supporting the instrument column (5) include a clamping ring (28) and at least one O-ring seal (29, 30). Axial movement of the instrument column (5) enables clamping of the inner seal (30) via the clamping ring (28). When axial movement of the instrument column (5) is restricted, the seals may be clamped by means of a suitably sized clamping ring (28).

Abstract: A thermal sleeve for insertion into a feedwater nozzle bore of a reactor pressure vessel for a nuclear reactor is described. In one embodiment, the sleeve includes a substantially cylindrical main body and a substantially cylindrical interference ring. The interference ring has a first secured end and a second free end. The interference ring is connected at the first secured end to an exterior surface of the substantially cylindrical main body. An interference surface is located at the second free end of the ring. The second free end of the cylindrical interference ring is biased so that when the sleeve is positioned in the nozzle bore, the second free end is biased towards the nozzle bore wall. In one embodiment, the second free end is biased into contact with a surface of an outer sleeve which also is positioned in the nozzle bore. The connector, a nozzle safe end wall, the outer sleeve and the inner sleeve cooperate to define a stagnant water area.

Abstract: The instrumentation column (5) comes to bear via a bearing surface and a sealing gasket (16) inside a bearing element including a tubular length (8) and a closure cover (11) joined together by screwed assembly means. The tubular length (8) and the cover (11) each include a bearing surface (33a, 34) which is symmetrical of revolution about the axis of the instrumentation column (5). The bearing surface (33a) of the cover (11) and the bearing surface (34) of the tubular length (8) between them, through direct metal-to-metal contact, provide sealing against the pressurized water of the reactor.

Abstract: A system for sealing the nozzle of a steam generator including a collapsible nozzle dam and an installation pivot arm. The collapsible nozzle dam includes a base portion receivable through a manway in the steam generator for retaining an inflatable seal in place within the nozzle, a post extending from the base portion, a plurality of foot assemblies positioned radially about the post for engaging a nozzle ring around the nozzle of the steam generator, a truss structure for supporting the foot assemblies with respect to said base portion including compression legs interconnecting the foot assemblies with the base portion and tension legs interconnecting the foot assemblies with the post. The foot assemblies fold about the post for insertion thereof through the manway to unfold once inside the steam generator for engaging the nozzle ring and positioning the base portion within the nozzle.

Abstract: An omega seal (32) between a housing (24) having a circumferential omega lip (38) including a free end, and a reactor vessel nozzle (22) having a complimentary omega lip (40) including a free end. A semi-rigid, annular seat member (60) is placed within one of the lips, and the housing is positioned in vertical alignment with the nozzle so that the free end of the housing lip and the free end of the nozzle lip are juxtaposed, thereby forming an omega structure having a cavity (44) occupied by the seat member, a gap (42) between the free ends of the lips, and an outer surface (47,49) on either side of the gap. A semi-rigid ring (46) is positioned in conforming relation to the outside surface of the omega structure. A compressive force is applied and maintained on the exterior of the seal ring, thereby extruding a portion of the ring into the gap.

Abstract: A nuclear power plant fuel transfer tube quick operating remote closure device (10) comprised of a reducing ring (20) and a cover assembly (60). The reducing ring (20) is bolted to the transfer tube housing flange (12). Rotation of a chuck key advances jaws on the cover assembly (60) which feed closure latches (78) into a groove (40) on the reducing ring (20). The upper surface (80) of each latch (78) has a bevelled surface (82) corresponding to a bevelled surface (42) of the groove (40). As the latches (78) engage the groove bevelled surface (42), the entire cover assembly (60) is uniformly drawn toward the reducing ring (20). Machined seal faces (13, 30, 44, 68) and O rings (36, 74) provide a fluid and air tight seal between the transfer tube housing flange (12) and the sealing ring (20) and between the cover assembly (60) and the sealing ring (20).

Abstract: A fluid tight mechanical clamp for creating a compressed graphite seal between a resistance temperature detector nozzle and a NSSS piping hot or cold leg pipe is provided which includes a split graphite seal ring, a peripheral seal back-up ring, a split load sleeve to axially compress and radially expand the split seal ring, a reactor plate and load ring with bolts to drive the load sleeve and compress the seal, and a blowout retainer to prevent the nozzle from blowing out of its seat in the pipe wall in the event of a weld failure. Extensive welding procedures to repair nozzle leaks are thus eliminated.

Abstract: The invention disclosed herein provides nozzles for vessels such as a pressurizer vessel, reactor vessel or piping in a nuclear power facility, and methods for attaching and sealing the nozzles to the vessels without any welding at all, i.e., without using a structural or seal weld. The nozzles are clamped or bolted to the vessel or attached by an interference fit, and a mechanical seal is obtained using gasket material and/or contacting, preferably polished, metal surfaces. Some embodiments of clamping the nozzle to the vessel comprise tightening a nut on the threaded end of the nozzle projecting from the bore in the vessel against the vessel, and structure which prevents the nozzle from being withdrawn through the bore, thereby clamping the nozzle against the vessel. Another embodiment of clamping a nozzle to the vessel comprises a sleeve threaded in the bore and forcing an interfering portion of the nozzle body into engagement with the bore.

Abstract: A self-aligning seal system for facilitating the repair or replacement of components of recirculation pump assemblies which penetrate the bottom head of the reactor pressure vessel of a boiling water reactor. The self-aligning seal system enables an operator to block off stub openings in the bottom portion of a water-filled reactor pressure vessel while performing maintenance in an underlying dry field without draining the coolant water from the reactor pressure vessel. To prevent leakage due to misalignment of the seal relative to the open end of the stub, the seal system is provided with a self-alignment guide member which centers the sealing unit relative to a diffuser opening coaxial with the stub as the sealing unit is lowered onto the stub.

Abstract: The surface of the component (1, 2) to be protected is scanned, a jet of semitransferred arc plasma (17) into which a metal powder is introduced. The process can be applied to the production of a layer of coating (18) on the outer surface of a region of welding connection (3) between a nozzle (1) and a primary pipe (2) of a pressurized water nuclear reactor or to the coating of the inner surface or the connecting surface of an adapter passing through the reactor vessel head.

Abstract: In order to reduce the time and difficulty of disassembling a seal arrangement in a cramped radioactive environment, a nozzle assembly hub is provided with a step bore which receives a seal arrangement, a compression collar, and a retaining nut which presses the seal arrangement into engagement with an inner wall portion of the hub and an outer wall portion of an ICI (in-core instrument) seal plug assembly. The ICI units remain connected to the seal plug assembly during normal disassembly operations. In this manner, the nozzle assembly may be disassembled by merely removing the retaining nut, compression collar, and seal arrangement and lifting the reactor head, along with the nozzle assembly, over the ICI units. The compression collar extends outside the retaining nut such that the collar can be engaged and compressed by an hydraulic loading tool while threading the retaining nut onto the hub.

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: The device includes a removable supporting end piece (26) which comes to rest on the top end part of a support assembly (21) fixed to the end of a port adapter of the head of the vessel of a nuclear reactor, and a pressure plate (28) including an odd number of lifting screws (31), so as to move the instrumentation column (22) upward and to clamp it against a support surface (24). A tightening assembly (35) for the lifting screws includes a tightening spindle (42a) having an end part (45) shaped to receive a tool (40) for rotating the spindle, and in turn rotates tightening spindles mounted so as to idle in the mounting plate (38) of the tightening assembly (35). The tightening spindles comprise shaped end parts (46a) coming into engagement with drive parts (31b) of the lifting screws (31) of the pressure plate (28), so as to tighten all the lifting screws simultaneously.

Abstract: A tool for remotely installing a plug in a steam line of a reactor vessel. The tool has a strongback assembly on which a plug is securely mounted, a collapsible structure (e.g., a scissors jack assembly) which supports the strongback assembly and is movable between an extended state and a collapsed state, a hanging bracket assembly for hanging the collapsible structure inside the reactor vessel, and a rotatable actuating screw coupled to the collapsible structure. The collapsible structure moves between the extended and collapsed states in response to rotation of the actuating screw. During this operation, the plug is carried from a retracted position outside and aligned with the steam line nozzle to an inserted position inside the nozzle.

Abstract: A nozzle includes a barrel being integral with a vessel and includes a first bore. A safe end is joined at one end to the barrel by a first weld and at an opposite end to an inlet pipe at a second weld. A first thermal sleeve is disposed inside the first bore and has one end disposed in an interference fit with a second bore of the safe end. In order to repair the nozzle for reducing leakage at the interference fit between the first and second bores, a method includes removing a portion of the inlet pipe and the weld at the safe end and installing a replacement extension therefor. The extension includes a tubular body having a first fork at one end joined to the safe end by a replacement weld, and having a distal end joined to the inlet pipe at a third weld. A second fork is disposed concentrically inside the body and is integrally joined at one end with an intermediate portion of the body, and includes a distal end extending toward the safe end.

Abstract: A nozzle dam has a valve controlled passage through the nozzle dam wall for releasing trapped gas from the nozzle in the region below the nozzle dam. The gas is released while the reactor coolant system water general level is above the level of the nozzle dam.