Abstract: In a method for sealing a hollow, elongate member within a reactor pressure vessel of a nuclear reactor, a section of the elongate member may be removed to separate the elongate member into an upper portion and a lower portion with an opening there between. The lower portion may be attached to a surface of the reactor pressure vessel in-situ, so as to seal off a potential leakage path through the elongate member.

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: The invention relates to a method of repairing the labyrinth seal of a diffuser in a primary pump, the diffuser being of the type comprising a peripheral skirt and a circular end wall having an orifice provided with the labyrinth seal. The method consists in making a bore in the circular end wall having a diameter greater than that of the orifice, in reducing the thickness of the remaining portion of the end wall, in forming a chamfer on the edge of the bore, in positioning a replacement part in said bore, the replacement part including a central orifice and a chamfer on its own peripheral edge, in making a bead of welding between the chamfers, and in making a new labyrinth seal in the central orifice of the replacement part.

Abstract: There is provided a nuclear power station primary pump of the type comprising a drive shaft for rotating a wheel, a heat exchanger, a thermal barrier cover comprising a peripheral skirt provided at its base with a circular end wall, and a diffuser comprising a peripheral skirt provided at its base with a rim. The circular end wall co-operates with the base of the heat exchanger to define a bottom chamber for cold water and includes a central bore provided with a succession of circumferential and superposed rings forming a lip seal of the labyrinth type, and a space is formed between the thermal barrier cover and the diffuser to maintain stagnant cooling fluid.

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 protective hose, and a method of making the same, for an in-core instrument assembly used in a nuclear reactor, including a first end that is hermetically sealed to a first member of in-core instrument assembly such as a bullet nose, a second end that is hermetically sealed to a second member of said in-core instrument assembly such as a seal plug, and a body portion that surrounds at least one detector in the in-core instrument assembly, and has flexible, corrugated outer and inner surfaces. The body portion includes a series of ribs having peaks. The hose is compacted in length to a degree that the peaks of the ribs are substantially adjacent to one another. The ribs also have side surfaces that decline from the peaks to valley portions that are disposed between the side surfaces. The hose is compacted in length to a degree that the side surfaces are completely in physical contact with one another.

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 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: An in-situ testing apparatus for testing the integrity of rib plugs used to seal faulty reactor boiler tubes consists of a cup-shaped member with a groove on the open end, a tapped hole for attaching a hydraulic hose of known pressure, and a hole through the top of the member. A seal is installed in the groove on the open end of the cup to seal to the primary face of a tubesheet around the tested rib plug. A threaded mandrel goes through the hole in the top of the cup-shaped member and engages the expander member of the rib plug. The threading action of the mandrel into the expander draws the seal against the tubesheet to seal the testing apparatus and allows the rib plug to be in-situ pressure tested.

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 nuclear power plant comprising a casing which encloses a primary space, a reactor vessel arranged in the primary space, and a reactor core provided in the reactor vessel. The plant further comprises an upper space provided above the casing. The reactor core is separated from the upper space by means of an openable cover arrangement. The casing is designed in such a manner that the primary space is completely closed against the environment to at least the level corresponding to the most highly located part of the reactor core. The upper space is arranged to house a volume of a liquid sufficiently large to permit the filling of the primary space with the liquid to a level located above the most highly located part of the reactor core.

Abstract: A seal assembly for sealing a space between an annular flange on a nuclear reactor vessel and a surrounding ledge of a refueling canal to provide a temporary water barrier during refueling operations. The seal assembly includes an annular closure plate having an outer portion secured to the surrounding ledge and an inner portion supporting a first sealing surface. A second sealing surface opposing the first sealing surface is formed on or secured to the annular flange of the reactor vessel. An annular space between the first and second sealing surfaces provides a ventilation path from the reactor cavity during normal plant operation. The annular space is sealed by an inflatable seal during refueling operations to provide a water barrier between the refueling canal and the reactor vessel. The inflatable seal is secured to and supported by an annular support structure that straddles the annular space.

Abstract: A method of temporarily sealing a reactor pressure vessel during an outage permits the water level in the vessel to be drawn down to a level which enables the interior surfaces of associated structures and equipment in the primary coolant loop to be inspected while dry when the vessel is submerged in a pool of water. A reactor pressure vessel internals lifting rig is used to position a temporary reactor pressure vessel head having an elliptical shaped dome with a circumferential flange retaining a pair of spaced apart, circumferential seal rings onto a reactor pressure vessel circumferential flange without marking or damaging the reactor pressure vessel flange.

Abstract: Downcommer coupling apparatus and methods for replacing a core spray line downcommer pipe coupled to a shroud T-box are described. In one embodiment, the coupling apparatus includes a wedge flange, a wedge, a wedge housing, a pipe seal, a cylindrical pipe, an elbow, a lower flange, and a shroud seal. The downcommer pipe is connected to the coupling apparatus by extending the pipe through the wedge flange, the wedge, and the wedge housing. The wedge has a plurality of flexible thinned segments that extend into the wedge housing to secure the downcommer pipe to the wedge housing. Wedge flange bolts extend through the wedge flange, the wedge, and the wedge housing to rigidly secure the downcommer pipe to the coupling apparatus. Dowel bolts extend through the wedge housing and the downcommer pipe to provide vertical and torsional load transfer from the downcommer pipe to the coupling apparatus. The lower flange is configured to receive the shroud T-box.

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: A tool fixture device for positioning tools to repair defects adjacent to the sealing grooves in a pressure vessel head. The device includes a two pair of parallel, spaced apart, arcuate segments adapted to fit into one of the sealing grooves. A support plate is attached to the first and the second pair of parallel, spaced apart, arcuate segments. The fixture includes a plurality of threaded rods for expanding the ends of the parallel arcuate segments to engage the inside walls of one of the grooves to hold the fixture in place. In the preferred embodiment, a tool positioner is adapted to be attached to the support plate for positioning a repair tool to permit the repair tool to be used to repair defects adjacent to the sealing grooves. The tool positioner includes a planar table and a tool jig attached to the planar table for receiving the repair tool.

Abstract: A system for seating at least one gasket member used to seal a pressure vessel penetration where a column penetrates therethrough includes a tubular member, a column which penetrates through the tubular member in a telescoping manner and is normally movable axially relative to and in axial sliding communication with the tubular member before assembly of hardware used to seat the gasket member, and at least one gasket member for sealing the interfaces between the tubular member and the column. The system also includes spacer for filling the axial gap in series with at least one properly seated gasket member between the column and the tubular member and at least one properly seated gasket member when the column cannot be suitably positioned axially relative to the tubular member in order to properly seat at least one gasket member during assembly of hardware utilized to seat at least one gasket member.

Abstract: Methods for sealing cracks adjacent stub tube attachment welds in a reactor pressure vessel of a nuclear reactor are described. The reactor pressure vessel includes at least one stub tube through which a control rod housing extends. The control rod housing is attached to one end of the stub tube with an upper stub tube attachment weld. In one embodiment, a sidewall of a control rod drive housing is cut at a location below the upper stub tube attachment weld to form a weld passage in the control rod drive housing between the control rod drive housing and the stub tube. A weld is then formed in the weld passage so that it is in physical contact with both the stub tube and the control rod housing, and thus seals the control rod drive housing against the stub tube.

Abstract: The measurement device includes a means (18) for leaktight passage of a measurement conduit (20), produced in the form of a thimble, and an element (25) for connecting the end of the measurement conduit (20) to a smooth cylindrical extension element. The connection element (25) is produced in the form of a sleeve (26), the internal bore of which includes a first part (35) for receiving the measurement conduit (20) and a second part (36) for receiving the smooth cylindrical extension element. The connection element (25) includes, at the ends of the sleeve (26), a first removable means (28) for fastening and leaktight passage of the measurement conduit (20), and a second removable means (30) for fastening and leaktight passage of the smooth cylindrical extension element. The invention applies both to mobile-probe devices for measuring in the core of the reactor and to fixed-probe measurement devices.

Abstract: A bottom head dome assembly which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome is described. The bottom head dome has a plurality of openings extending therethrough. The liner also has a plurality of openings extending therethrough, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending therethrough, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner.

Abstract: A method for sealing cracks adjacent stub tube attachment welds in a reactor pressure vessel of a nuclear reactor is described. The reactor pressure vessel includes at least one stub tube through which a control rod housing extends. The control rod housing is attached to one end of the stub tube with an upper stub tube attachment weld. A sidewall of a control rod drive housing is cut at a location below the upper stub tube attachment weld to separate an upper portion of the control rod housing from a lower portion of the control rod housing. The lower portion of the control rod drive housing is removed from the bottom head opening, and a replacement lower portion is positioned in the bottom head opening proximate to the remaining upper portion. The replacement lower portion then is secured to the reactor pressure vessel without securing the replacement lower portion to the remaining upper portion of the control rod drive housing.

Abstract: A nuclear power plant has a cooling system that operates under a variety of temperature and pressure conditions. A storage container is provided to allow expansion of fluid within the cooling system, and access is gained to the interior chamber of the container via a rupture disc. When pressure above a design threshold is exceeded, the rupture disc ruptures allowing fluid to fill the chamber. When desired, a valve may be opened to allow fluid to exit the chamber and travel to a desired location.

Abstract: A tight crossing to ensure a high efficiency seal between the interior (1) and the exterior (2) of a high activity cell. The crossing comprises a sleeve (6) placed in the wall (3), a guide tube (11) placed within the sleeve (6) and a support flange (12) placed between the sleeve (6) and the guide tube (11) on its outer end. A joint holder flange or ring (15) is placed in the cell interior (1) and is secured against the cell skin (4), the guide tube (11) and the sleeve (6) by means of captive bolts (18).

Abstract: A circular outage cover of light-weight composite material is normally situated in a standby position adjacent to the opening at the outer end of the equipment access tunnel of a nuclear reactor containment vessel. In case of an emergency during an outage, the outage cover can be quickly rolled into position and engaged with a transition ring provided as an extension of the tunnel by retractable retaining shoes on the retaining ring and an inflatable seal carried by the outage cover. The ability of the outage cover to be closed quickly makes it possible to keep the operational cover open throughout most of the outage, and reduces the overall outage time. Hydraulic, pneumatic and electrical services pass radially through the transition ring and do not interfere with closure of the outage cover. An auxiliary diaphragm cooperable with the transition ring is used for pressure testing of the outage cover.

Abstract: A reactor vessel seal for temporarily sealing a reactor pressure vessel from a water-filled refueling canal above the reactor pressure vessel. The reactor vessel seal is installed in place of the removable reactor pressure vessel closure head for inspecting/servicing the reactor vessel. The reactor seal comprises a seal cap having a surface connected to a flange which is complementary to the upper flange of the reactor pressure vessel. A seal is located between the seal cap flange and the upper flange of the reactor pressure vessel. A lifting rig is connected to the seal cap for lifting the seal cap and placing it in position, with the seal cap flange in alignment with the reactor vessel upper flange, such that the seal located between the seal cap flange and the reactor pressure vessel upper flange is compressed by hydrostatic pressure from water in the water-filled refueling canal acting on the surface of the seal cap as water in the reactor pressure vessel is evacuated.

Abstract: In order to plug a pressure vessel penetration through which a heater was disposed, a stepped diameter hollow cylinder is provided with grafoil seals which are set on an annular shoulder defined by the stepped diameters of the cylinder and compressed against a lower annular edge of a sleeve which is partially machined away. The hollow cylinder is locked in position in the sleeve by a plurality of barb-shaped flanges which are formed at the upper ends of a plurality of flexible finger-like segments defined in the upper end of the hollow cylinder, and which engage the upper end of the sleeve. A rod is disposed in the hollow cylinder and welded in positon to complete the plug.

Abstract: A nuclear containment arrangement has a permanent pool cavity seal extending across an annular gap between a reactor pressure vessel and a refueling pool wall to provide a water tight seal therebetween. A seal plate has a support ring with a cylindrical section weldedly connected to an outer seal ring on an embedded ring. A J-shaped flexible ring attached to the seal plate allows axial and radial movement of the reactor vessel during thermal expansion and contraction. The inner portion of the seal plate overhangs the J-shaped flexible ring thereby to protect it from damage resulting from an object dropped thereon. Cooperating access holes and access hole covers in the seal plate provide access to the refueling pool cavity. Support arms underneath the seal plate are provided. Each support arm may have leveling screws to adjust the level of the seal plate.

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: 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: A device for preventing moisture, debris or other liquids from entering a hole adapted to receive a threaded member. The device comprises an interior plug having an external thread, an exterior plug having substantially the same diameter as the hole and suitably adapted such the top surface of the exterior plug is adapted to translate toward the interior plug when the threaded member is inserted into the hole. A resilient means, such as a spring, returning the exterior plug to a position such that its top surface is co-planar with the surface surrounding the hole when the threaded member is withdrawn from the hole.

Abstract: A plug which is inserted into the nozzle of nuclear reactor steam line is provided with a set of inflatable primary seals which resemble a pair of tires. A locking ring which features pads which can be hydraulically driven radially outward into engagement with the nozzle wall, is located adjacent the tire-like inflatable seals. The latter are inflated by a spring loaded piston. A tool which inserts the plug into the nozzle is adapted to tract the piston against the bias of the preloading springs, until such time as the plug is inserted into position. After insertion the piston is released and the seals are inflated.

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 clamping and locking device (18) of the clamp includes a screw (22) arranged in a direction which is transverse with respect to the articulated elements of the clamp and engaged through two blocks (19, 19') bearing on two articulated elements of the clamp, which include two guide journals (20a, 20b) each engaged and held in an opening of a bar (26a, 26b). The openings (27a, 27b; 28a, 28b) include a pair (27a, 27b) of circular openings and a pair (28a, 28b) of oblong openings. Nuts (25, 25') allow the clamp to be clamped and locked. The clamp further includes a blocking device (31) consisting of a support (33) including a strut (34) traversed by an opening and including parts (35a, 35b) for engagement on the bars (26a, 26b), a lock nut (37) rotationally mounted in the opening of the support (33), an arrangement (41) for blocking the lock nut (37) in rotation and in axial translation, and at least one blocking finger (44a, 44b) pivotably mounted on the support (33).

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

Abstract: An arrangement of reactor coolant pump seals arranged in a generally annular stack with a plurality of stacking spacers in a test housing for emplacement in a chemical decontamination test loop enables a variety of flow characteristics to be simulated by varying the detailed arrangement of the RCP seals and supporting structure in the test housing. By adjusting parameters such as fluid chemistry, gross flow, pressure, and temperature in a controlled manner with systems incorporated into the test loop, additional information can be obtained regarding the feasibility of any specific decontamination process. The magnitude of process fluid flow across particular surfaces of one or more RCP seal components can be predetermined by selecting the placement, number and dimensions of penetrations in a flow distribution tube through which the process fluid enters the housing.

Abstract: Tube plug and method for plugging a heat exchanger tube having an inner wall, which tube plug has a reduced susceptibility to stress corrosion cracking. The tube plug includes a shell having a closed end, an open end and an outer wall, the shell defining a chamber therein in communication with the open end of the shell. Disposed in the chamber is an expander member for expanding the outer wall of the shell into sealing engagement with the inner wall of the tube. A sealing member engages the expander member and is disposed across the open end of the shell for sealing the chamber defined by the shell so that fluid can not enter the chamber to corrosively attack the shell.

Abstract: The confining and covering enclosure (10) comprises a heat-insulating wall (13, 14) designed to insulate thermally the outer surface (2a) of the vessel head (2). The heat-insulating wall (13, 14) is leaktight to the fluid coming from the vessel of the reactor in the case of leakage and comprises leaktight connection seals (15, 27) at the outer surface (2a) of the head and at the adaptors (6) serving to delimit a chamber (30) for confinement and for recovery of leakage gases.

Abstract: A permanent annular ring seal and refueling deck assembly providing an effective water barrier over the annular space between a nuclear reactor vessel flange and a surrounding annular ledge includes annular platform, a support and a joint seal. The joint seal has an upper cylindrical section and a lower flexible corrugated or arcuate shaped section which accommodates radial, axial and rotational movements of the vessel, and reduces joint stress.

Abstract: Extrusion-resistant seal assembly for sealing a gap defined between a first structure spaced-apart from a second structure, which first structure and second structure may be an annular first flange and an annular second flange belonging to an instrumentation column of the kind typically found penetrating nuclear reactor pressure vessels. The seal assembly includes an annular retainer disposed in a gap defined between the first flange and the second flange, the first flange and the second flange capable of being moved into close proximity to reduce the gap therebetween. The retainer includes a first surface thereon having a first recess extending therearound. The retainer also has a second surface thereon having a second recess extending therearound. An annular first gasket is retained in the first recess and an annular second gasket is retained in the second recess.

Abstract: A self-aligning seal system for use in carrying out maintenance services in a nuclear fission reactor plant is disclosed. The self-aligning seal system enables an operator to block off openings in the lower portion of a water filled reactor pressure vessel for maintenance service in an underlying dry field without draining the coolant water from the reactor pressure vessel.

Abstract: A fastener for fastening together a plurality of members, such as the plurality of members comprising a tube plug, and a method for plugging an opening in a solid member, which may be a tube, for preventing the flow of fluid through the opening in a solid member or through the tube, such as a nuclear steam generator tube, comprises a first member, such as a shell, a second member, such as a bolt, and locking structure. A deformable tab portion of the locking structure may have an undercut positioned so that when the second member is installed within the first member, a first surface of the undercut is bent toward a second surface of the undercut thereby plastically deforming the tab portion into a recess in at least one of the first and the second members for automatically securing together the plurality of members.

Abstract: A mechanically actuated plug comprises a pole system to lower a pair of seals into a refueling pool in a Boiling Water Reactor ("BWR") plant. A plug adapter is connected to the end of a pole system and is attached to a scissors jack assembly. The scissors jack assembly is comprised of at least one jack screw shaft, at least a pair of nuts, scissor arms connected between the nuts and the seals, and scissor arms connected between the nuts and a loading pad. The pole and plug adapter have a central shaft assembly which is connected to the jack screw shaft and transfers rotational motion from the top of the pole to the jack screw shaft. By rotating the central shaft assembly, the plug may be opened to seal the recirculation line. Once opened, the pole and plug adapter are preferably detached from the plug so that the plug may remain in position while the pole system is removed from the refueling pool.

Abstract: An apparatus is provided for moving shielding plugs into and out of holes in concrete shielding walls in hot cells for handling radioactive materials without the use of external moving equipment. The apparatus provides a means whereby a shield plug is extracted from its hole and then swung approximately 90 degrees out of the way so that the hole may be accessed. The apparatus uses hinges to slide the plug in and out and to rotate it out of the way, the hinge apparatus also supporting the weight of the plug in all positions, with the load of the plug being transferred to a vertical wall by means of a bolting arrangement.