Abstract: A captive fastener is joinable to a stud for being retained in a nuclear reactor. The fastener includes a head fixedly joinable to the stud, and at least one spring clip extending perpendicularly from the head and having a proximal end fixedly joined thereto, and a distal end in the form of hook for retaining the fastener in the reactor. The hook is resiliently deflectable laterally relative to the head for allowing assembly and disassembly.

Abstract: An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor.

Abstract: A thimble tube for use in a guide the in a nuclear reactor. The thimble tube is an elongated hollow tube having one end closed. The portion of the tube that extends into the reactor is formed from a plurality of sections attached to each other to form the tube in an alternating fashion along the width and length of the tube. The sections are formed from materials having different coefficients of thermal expansion. This causes the thimble tube to warp into supporting contact with the interior of the guide tube at normal reactor operating temperature.

Abstract: Radioactivity exposure amount of workcraftmen is obtained through simulation by using an operation processor when the workcraftmen carry out work operation within an area under controlled radioactivity. The movement of the workcraftmen carrying out work operation in the area under controlled radioactivity is simulated by making use of layout graphic data relating to the area. The radioactivity exposure amount of the workcraftmen is calculated in response to the simulated movement of the workcraftmen. The operation procedures of the target work operation for radioactivity exposure amount calculation is outputted from the operation processor, when the calculated radioactivity exposure amount satisfies a predetermined value.

Abstract: An apparatus for form-locking torsion prevention in screw connections includes a bolt with a standard bolt thread and a special nut having a free end and nut threads. A thin-walled sheath is disposed on the free end of the special nut. An integral cross-sectional portion intended for deformation is in the form of a bead supported on the thin-walled sheath. The nut thread extends uninterruptedly through the sheath and the bead. The bolt thread extends through the bead. A thrust pad is pressed axially onto the bead and has a conically narrowing bore formed therein in which the bead is substantially radially plastically deformed and forced inward into the bolt thread.

Abstract: A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

Abstract: Lower internals for a reactor--typically a PWR--having a pressure vessel containing a core cooled by an upward flow of coolant and a core support include a shell defining a coolant volume between the support plate and the lower part of the vessel. The shell has a wall and ducts opening into passages of the support plate. Guide tubes passing through the volume receive glove fingers for in-core instrumentation probes. The internals further include a separation plate fixed to the wall means, situated below the core support plate. The separation plate is formed with holes connected to the coolant conveying ducts and is fixed to the lower support plate of the core by mechanical connection means spaced apart at the periphery of the separation plate and defining passages for radial access of the coolant to the distribution chamber.

Abstract: An apparatus and process for control rod assembly and construction for a nuclear reactor is disclosed wherein the control rod is of cruciform configuration having a plurality of and preferably four flat planar members. Each planar member is made up with an assembly of square cross sectioned tubular members. Each square cross sectioned tubular member includes a defined cylindrical center and a constant thickness surrounding tubular metallic shell to provide the contained neutron absorbing materials in a cylindrically shaped pressure vessel. The constant thickness surrounding tubular shell constituting the cylindrical shaped pressure vessel has four corner sections added to generate a modified square exterior profile. These added four corner sections comprise an addition to the tubular side wall thickness of the shell. Appropriate chamfers and rounding are provided to the square profile to impart both stress relief and convenient points for automated welding between side-by-side square sections.

Abstract: A reconstitutable control assembly has a spider structure which supports control rods by detachable attachment joints. Each attachment joint includes a hollow connecting finger on the spider structure and an elongated detachable split upper end plug on each control rod. The split upper end plug includes a pair of separate upper and lower plug portions. The upper plug portion has upper, middle and lower sections, whereas the lower plug portion has upper, middle and lower segments. The upper section of the upper plug portion is rigidly attached to the connecting finger on the spider structure, whereas the lower segment of the lower plug portion is rigidly connected to the control rod. Also, the lower section of the upper plug portion and the middle segment of the lower plug portion have complementary threads defined thereon for rigidly threadably attaching the upper and lower plug portions to one another.

Abstract: Method for extending service life of nuclear reactor components prepared from ductile, high strength crystalline alloys obtained by devitrification of metallic glasses. Two variations of the method are described: (1) cycling the temperature of the nuclear reactor between the operating temperature which leads to irradiation damage and a lThe U.S. Government has rights in this invention by virtue of Department of Energy, Office of Fusion Energy, Grant No. DE-AC02-78ER-10107.

Abstract: A spider assembly for supporting a corresponding rod cluster in a pressurized water reactor vessel, through which the core outlet flow passes in a predetermined direction. Each spider assembly comprises a generally cylindrical, central hub disposed in parallel axial relationship to the predetermined direction of the core outlet flow and a plurality of vane assemblies. Each vane assembly comprises means for mounting at least one rod to the assembly and at least one vane element connecting the rod mounting means to the hub. Each vane element has generally parallel, major planar surfaces disposed parallel to the predetermined direction of flow and a square trailing edge configuration which mitigates the shedding forcing function on the spider resulting from the core outlet flow thereover, while maximizing material content and thereby the strength thereof.

Abstract: A temporary support structure for supporting a lower internals assembly above the reactor vessel during inspection and/or maintenance thereof. A support bracket is bolted to the reactor vessel flange at the vessel head stud closure holes. A pivotally mounted arm, upon the top surface of which the internals rest, is attached at one end to the support bracket and projects radially inwardly therefrom. A compliant foot depends from the bottom of the opposite end of the arm and engages the vessel internals support ledge to provide a secure support structure for the internals assembly. An alignment bracket on the arm aligns the internals with the support. Four such structures are installed around the circumference of the vessel flange while the internals are within the reactor vessel. The structure allows the lower internals to be quickly removed from the interior of the reactor vessel and placed on the temporary supports.

Abstract: An insert for providing a reduced inside diameter for a structural tube, specifically an instrumentation guide tube, of a nuclear fuel assembly. The insert has forming lobes which coact with the structural tube to plastically deform the structural tube and mechanically lock it with respect to grid straps of a grid assembly. The insert also has centering lobes to prevent it from being expanded in other than a coaxial alignment with the structural tube. An expansion tool is provided for sequentially registering with and expanding sequential forming lobes in a simplified manner whereby all of the operations necessary to assemble the structural tube in the fuel assembly can be easily and accurately performed.

Abstract: A pressurized water reactor of an advanced design comprises, in vertically spaced relationship, a lower barrel assembly having lower and upper core plates, an inner barrel assembly and an axially removable calandria assembly having a lower calandria plate. A plurality of rod guides are cantilever-mounted in parallel axial relationship within the inner barrel assembly by rigidly mounting the lower ends thereof to the upper core plate. Axially extending sleeves affixed to the upper ends of the rod guides and telescopingly receive therein generally cylindrical supports which are affixed to and depend downwardly from the lower calandria plate and define alignment axes for the respectively associated rod guides. Axially extending leaf springs in each sleeve are normally biased radially inwardly and, in the assembled relationship of the calandria and inner barrel assemblies, resiliently and frictionally engage the respective cylindrical supports to maintain alignment and react both lateral and axial loads.

Abstract: A wiring installation for electrical connections of a plurality of devices of a nuclear reactor, comprising: (a) a plurality of first multiwire cables each extending at least from certain ones of said devices and terminated with a first connector located above said cover at an end remote from said device, and (b) a plurality of second multiwire cables each for connection with a respective one of the first cables and each having a first section having a first multicables connector having a plurality of electrical contacts connected to respective wires of said section, said first multicables connector being common to at least ten independent first sections, and a second section having a second multicables connector having a plurality of electrical contacts connected to respective wires of said second section and corresponding to respective wires of said first section for removable connection to said first multicables connector.

Abstract: Removable and lockable guide ring in an orifice passing through a plate and its use for a guide tube of a nuclear reactor. The guide ring comprises a tubular body (25), one part (25a) of which is introduced into the orifice (22) in the plate (20). A second part (25b) of the tubular body (25) comes up against the plate (20), and claws (40) having the form of being levers, for attaching the ring (21) to the edges of the orifice (22), are mounted freely in the tubular body (25). A spring (45) makes it possible to return the claws (40) into the attachment position. The invention applies particularly to a guide tube of a pressurized-water nuclear reactor.

Abstract: Device for locking a guide ring on a plate having an orifice comprising a tubular intermediate piece (22) fastened rigidly to a plate (20) so that its central orifice (36) is coaxial with the orifice (32) in the plate (20), receptacles (28) machined radially in the intermediate piece (22) and separated by passages open towards one end of the intermediate piece, and attachment parts (39) which match the receptacles (28) of the intermediate piece (22) and which are associated with the guide ring (21). The invention is used particularly for locking the guide ring of an extension piece on a guide tube of a light-water nuclear reactor.

Abstract: A fluidic device, in particular a vortex diode, has a vortex chamber formed by spaced apart end walls and a peripheral side wall. An axial port is provided in one end wall and a further port permitting tangential flow into or out of the chamber is provided in the other end wall.

Abstract: A burnable absorber cluster assembly includes a support plate, a plurality of burnable absorber rods, and an improved attachment joint for detachably connecting an upper end of each of the absorber rods to the support plate. The attachment joint includes a plug insert defined on the end of each of the rods, a hollow annular wall extending outwardly from each plug insert, holes defined through the support plate for receiving the plug inserts, and recesses formed in the support plate and connected with the holes therein. Each recess is conical-shaped and extends in flared fashion outwardly from one hole to a maximum diameter greater than the diameter of the hole. The annular wall on each plug insert is deformed into conformity with the shape of one of the recesses for providing an interengaging connection between the insert plug and the support plate in which the plug insert is disposed within the support plate hole.

Abstract: A reactor stud hole plug unit having a mandrel with a central stem having a threaded upper portion, a longitudinal passageway extending therethrough and a mandrel plate attached to the lower end. The mandrel plate has threads on its periphery which engage internal threads on a stud hole in a nuclear reactor, and an annular stop is located at the upper end of the threads on the mandrel plate which engages a shoulder on the cavity when the mandrel plate is in position in a stud hole. A compression plate with a central opening having a diameter slightly larger than the diameter of the upper portion of the mandrel stem fits over the mandrel stem, and an annular sealing ring is positioned around the periphery of the mandrel plate above the annular shoulder and in contact with the compression plate when the compression plate is positioned over the mandrel stem.

Abstract: The reactor vessel thread protector is a metal cover that is placed over the exposed stud, nut and washer projecting above the closure head to protect the threads from accidental corrosive leakage impingement emitted from mechanical seals on the top of the reactor vessel head. The stud protector includes a drip pan to collect any such fluid being emitted from the reactor vessel. Additionally, the reactor vessel stud thread protector will provide protection from accidental deformation to a stud due to operator maintenance around adjacent studs. The reactor vessel stud thread protector can be in the form of a cylinder which would cover a single stud bolt or a curved box having a rectangular cross-section that would cover a plurality of stud bolts.

Abstract: Disclosed are a method of making a connection in a liquid and an apparatus therefor wherein a first connector having a protrusion at its front end is housed in a protecting tube which is open at its lower end and into which a gas is introduced, the protecting tube is filled with the gas so as to form a gaseous space therein within the liquid, a second connector which is normally held within the liquid and which has a destructible plate at its upper end is exposed to the gaseous space, and the destructible plate is destroyed by the front end of said one connector so as to connect both connectors, whereby the connection in the liquid can be made without being affected by an ambient liquid.

Abstract: In a nuclear reactor fuel assembly having a fuel rod filled with nuclear fuel retained in a gap formed in a lattice-like spacer by a spring disposed in the gap, the fuel assembly is repaired by replacing the fuel rod with a replacement rod and the replacement rod is retained in the gap of the spacer with a retaining spring.

Abstract: An elongate selector member 16 having a Y-shaped passage 16a extending through it is rotatably mounted in a hollow cylindrical housing 12 and driven or switched between fixed limit positions by an actuator 17 to establish a continuous insertion/withdrawal path for a flexible cable between an inlet guide tube 11 and either one of two outlet guide tubes 19a, 19b.

Abstract: A support for the top ends of plural rod guides of at least first and second types which are generally vertically disposed within a pressurized water reactor vessel in corresponding, first and second interleaved matrices. Lower ends of the rod guides are affixed to a lower support structure and the upper ends thereof are disposed adjacent to and spaced vertically below an upper support structure of the vessel. Corresponding, first and second types of top support plates are disposed on and connected to respective top ends of the first and second types of rod guides. The first and second types of top support plates have mating exterior peripheral surfaces which are assembled in sliding, telescoping relationship, a transverse extension from one peripheral surface being received in a vertically extending, recessed channel in a mating peripheral surface of the contiguous support plates.

Abstract: A device for suspending a core cover from a sealing slab of a fast neutron nuclear reactor of the type comprising a vertically axed vessel structure filled with liquid metal, closed by the slab and containing the reactor core. The device comprises an upper row and a lower row of superimposed, generally flat, planar, metal plates enabling the rows to be joined to the slab and to the core cover, each row of plates defining a closed convex envelope. The plates are flexible in a direction radial relative to the envelope, while being rigid in a direction circumferential with respect to the envelope. The two rows of flexible plates are interconnected by a lattice of rigid bars in an "X" or "V" form. The upper row plates have upper edges rigidly fixed in position relative to the slab and lower edges rigidly fixed in position relative to the lattice. The lower row plates have upper edges rigidly fixed in position relative to the lattice and lower edges rigidly fixed in position relative to the core cover.

Abstract: A high-temperature gas cooled nuclear reactor system comprises a containment building, a concrete reactor pressure vessel inside the containment building, and a safety relief valve connected to the concrete reactor pressure vessel. The spring of the safety valve consists of a material with a spring constant decreasing as temperature rises. A heat exchanger is provided in close proximity to cool the spring of the safety valve which is subject to the heat of the reactor coolant escaping when the safety valve is open. The heat exchanger of the safety valve is connected to a liner cooling system of the concrete reactor pressure vessel.

Abstract: A support pin system which is a non-welded system for fastening a first structural member, such as a nuclear reactor control rod guide tube flange, to a second structural member, such as nuclear reactor upper core plate, includes a support pin and nut. A first pin portion passes through the first member and has a threaded section which mates with the nut. A second pin portion has a solid body section and a split-leaf base section which biasingly engages a bore in the second member. The solid body section is accommodated by a close clearance fit. The split-leaf base section has an intermediate diameter which is less than the diameter of the solid body section. Thus, loads applied transversely to the system are reacted substantially in pure shear through the solid body section. The nut may be a locking nut having a crimpable cylindrical section integrally connected to an internally threaded section.

Abstract: A support pin system (10) for fastening nuclear reactor guide tube flanges (14) to a nuclear reactor upper core plate (12) includes a support pin (16) having a lower portion (20) frictionally disposed within the upper core plate (12), while an upper section (24) is disposed within a through-bore (22) of the guide tube flange (14). The support pin (16) includes a threaded region (30) upon which is threadedly mounted a nut (32). In order to prevent retrograde rotation of the nut (32) relative to the support pin (16), a locking cap (46) is mounted upon the nut (32) and support pin (16) such that first crimped sections (48) are engaged within apertures (44) defined within the nut (32), while second crimped sections (54) are engaged within longitudinal grooves (50) defined upon the external surface of the support pin (16).

Abstract: A flexureless insert guide assembly. An annular shaped body inserted through the hole in a guide structure card has spring loaded arms pivotally mounted in the body which snap outward to retain the assembly in place. The assembly has an exterior groove adapted to receive removal tooling which causes retraction of the arms for removal of the assembly.

Abstract: A bolt and keeper secure nuclear steam generation isolation dam segments in assembled relation. The bolt is rotated into locked position with its handle in a slot as a transverse projection on the bolt end is moved along a ramp into a securing notch against the bias of a compressible rubber spring.

Abstract: This hooking device is fastened to the choke plug (8) for guide tube (2). comprises of catches (54) regularly arrayed along the periphery of the flange (9) of the choke plug (8) and hooks to the upper spacer (4S) of the guide tube (2). It is kept in the engaged position by a spring system (56-58), 63-65) and can disengage by means of a tool means comprising a roller (77) acting on each catch (54) and a rim (68) resting on a muff (56) acting as a rest also for the spring (57).

Abstract: A stuck fuel rod capping sleeve to be used during derodding of spent fuel assemblies if a fuel rod becomes stuck in a partially withdrawn position and, thus, has to be severed. The capping sleeve has an inner sleeve made of a lower work hardening highly ductile material (e.g., Inconel 600) and an outer sleeve made of a moderately ductile material (e.g., 304 stainless steel). The inner sleeve may be made of an epoxy filler. The capping sleeve is placed on a fuel rod which is then severed by using a bolt cutter device.

Abstract: An electrical penetrator employs metal-sheathed insulated conductors that extend completely through and are sealed within a tubular housing. A filler block is disposed centrally within the housing and is surrounded by elastomeric material of a sealing member. Plugs are inserted into opposite ends of the housing so as to compress the elastomeric material and are sealed within the housing. Hollow end caps threaded into the opposite ends of the housing urge the plugs toward the elastomeric material. The metal-sheathed conductors extend through the hollow end caps and through longitudinal passages in the plugs and the sealing member. The conductors are sealed in the sealing member by the elastomeric material, are sealed in the plugs by tube fitting assemblies threaded into the plugs about the conductors, and are sealed in the hollow end caps by potting material.

Abstract: The invention relates to floating roof tanks for liquids, of the type comprising a cylindrical wall (2), a floating roof (3), and a flexible membrane (4) connecting the periphery of the floating roof to the wall. In accordance with the invention, the tank further includes an overflow duct for providing protection against over-filling when the roof (3) is in its top position. The overflow duct (26) is mounted on the outside of the tank and has an upsidedown U-shaped portion disposed at a height corresponding to a maximum predetermined level for liquid inside the tank when the roof is in its top position. The invention is applicable to the nuclear power industry for storage tanks for topping up the primary circuit of a nuclear reactor with de-gassed water.

Abstract: A system for remotely repairing nuclear fuel rod assemblies is disclosed herein. Generally, the system comprises a rod handler for gripping, lifting, lowering and ungripping a selected fuel rod, a work station for securing the nuclear fuel rod assembly to be repaired into a desired location, and a positioner device for laterally positioning the rod handler over a selected rod in the fuel assembly secured within the work station. The rod handler includes a contractable collet for gripping and ungripping a desired fuel rod, and a rod sensor concentrically disposed within the collet for sensing when a rod is in a grippable position. The positioner includes a movable carriage which is slidably mounted onto a frame assembly by means of a pair of rail and bearing mechanisms. The system also includes a microcomputer for controlling the manner in which the positioner positions the rod handler, as well as gripping, lifting, lowering and ungripping motions of the handler itself.

Abstract: A device for use in a nuclear reactor which includes a pressure vessel having a vessel head, a core in the vessel, elements for controlling the reactivity of the core, drive rods which pass through the vessel head for displacing the elements, and a plurality of head adapters which pass through the vessel head, each head adapter forming part of a drive rod housing enclosing a respective drive rod, each housing enclosing a region which communicates with the interior of the vessel and which is closed at the top. The drive is associated with a respective housing and constitutes a housing extension including a component for connecting the device to the head adapter forming part of the respective housing, and a component for forming, around the associated drive rod and within the associated housing, a fluid passage having a cross-sectional area not exceeding a selected value at least upon the occurrence of a leak in the respective housing.

Abstract: A grid assembly fixture for use in assembling grid straps to form a grid comprises a generally flat plate having first and second sets of parallel grooves, with the grooves of the sets at right angles. A retention strap comprises first and second pairs of bars, the bars of each pair hinged together adjacent their ends, and releasable joining elements for joining the pair of bars.A method of assembling the grid straps includes positioning a first set of straps in a grid assembly fixture, positioning a second set of straps at right angles to the first set to form a grid, placing outer straps on the grid, and placing a retention strap on the outer straps.

Abstract: An improved nuclear reactor wherein the bolted connections between the baffle plates and baffle former and the baffle former and the core barrel are provided with a noval locking device that prevents loosening of the bolted connections. The locking device to prevent loosening of bolted connections where a threaded bolt is used to secure two components together uses a threaded lock nut over the bolt head, cooperative with a threaded wall in a recess in a component. The lock nut and wall of the recess have threads opposite the threads of the bolt. Deformable sections are formed in the base of the lock nut to engage an unsymmetrical cavity in the head of the bolt. Turning of the bolt in a direction that would tend to loosen the connection causes tightening of the lock nut. The wall of the lock nut may be threadedly engaged with the wall of the recess or the lock nut wall may have slits formed thereon which enable deformation of wall portions to engage the threaded wall of the recess.

Abstract: Removable cruciforms are selectively installed at predetermined, spaced elevations within ice baskets associated with a nuclear power system, each ice basket having a generally cylindrical sidewall with plural, annular retaining rings secured therein at predetermined, spaced elevations, each cruciform being installed at predetermined, axially displaced elevations, engaging a corresponding annular retaining ring. Each cruciform comprises a pair of brackets joined together between parallel base portions by respective support plate assemblies and slide plates in telescoping, sliding relationshp, defining with the base portions, a spring housing of generally square configuration within which a generally C-shaped spring is received. A pair of legs extends integrally from the longitudinal edges of the base portion of each bracket, angularly disposed so as to extend radially within the ice basket.

Abstract: A crash protection apparatus for a pulling device having a hollow piston cylinder and a pulling claw for pulling a tube out of a tube sheet of a heat exchanger chamber in which the pulling device is disposed, the crash protection apparatus includes another cylinder without a piston rod having an axis substantially parallel to the axis of the hollow-piston cylinder and being fixed relative to the tube sheet in the chamber, a piston of the other cylinder, a bracket extending from the piston substantially at a right angle to the axis of the other cylinder for supporting the pulling device with a supporting force provided by the other cylinder, and a device for controlling the supporting force for compensating only the weight of the pulling device in each position of the pulling device.

Abstract: A control unit for a nuclear reactor constituted by a plurality of sealed vessels (17) communicating with the inside of the tank of the reactor (15) which they extend upwards above its cover (16); each containing a displacement mechanism for a unit absorbing neutrons in the core of the reactor. The drive motors (18) for the mechanisms are positioned in the upper part of the sealed vessels (17) within vertical aeration ducts (32). The control unit includes a supporting and insulating device for the sealed vessels (17) constituted by a vertical structure (23) fast to the cover of the tank (16), a horizontal strengthening plate (27) fixed to the upper part of the vertical structure (23) and a heat-insulating envelope (36) surrounding the sealed vessels (17) to a level below the level of the motors (18). The invention is particularly applicable to pressurized water nuclear reactors equipped with screw and nut mechanisms.

Abstract: A top end support for rod guides disposed in closely spaced, parallel axial relationship within an inner barrel assembly of a pressurized water reactor vessel includes, in telescoping relationship, a generally cylindrical support having an end closure with a central aperture therein for receiving a downwardly depending extension from a lower calandria plate and a sleeve having an outer periphery corresponding in cross-section to that of said rod guide and affixed thereto at its lower end, the sleeve having an interior, generally cylindrical surface for receiving the cylindrical support in close engagement therein. The telescopingly engaged, generally cylindrical surfaces of the cylindrical support and the sleeve provide substantial area to function as a long-life wear couple.

Abstract: A steam control value for a steam chest such as used in a nuclear plant with an improved muffler portion. The muffler portion includes window openings of predetermined dimensions. A ring portion is below the window opening having a plurality of pockets. Each pocket is aligned with one of the window openings. This design greatly reduces vibrations which may damage the valve.

Abstract: A process for improving resistance of control rod guide tube split pins in nuclear reactors to stress corrosion cracking comprising heating the split pin to a critical elevated temperature level, cooling at least the surface portions of the split subject to stress corrosion cracking and then permitting the split pin to come to ambient temperature.

Abstract: The responses of a nuclear reactor refueling machine to commands from a detachable control console are simulated to allow operation of the console for testing and operator training with the console removed from the machine. A simulator, which is connected to the console by the same input and output leads which normally connect the console to the refueling machine, includes a single pulse generator driven by a single three phase A-C motor to simulate movement of the refueling machine bridge, trolley and hoist. The motor drive signals generated on separate console output leads are all connected to the single simulator motor, while the brake release signals energize relays which switch the pulse signals generated by the single pulse generator to the console input leads corresponding to the selected refueling machine component drive motor.

Abstract: A core barrel hole plug. A plug body sized to easily fit the hole to be plugged is slidably attached to a flange sized larger than the hole to limit the movement of the plug body into the hole. A rectangular bore at the inner end of the plug body has a pair of pawls pivotally mounted therein which are moveable between retracted and extended positions for releasing or locking the plug in position. An actuator screw is threadably engaged through a cylindrical bore in the plug body and in communication with the rectangular bore where a cam on the actuator screw causes movement of the pawls between the release and locking positions. The flange and screw are adapted to receive a remotely operated tool for remote operation of the assembly.

Abstract: A reconstitutable fuel assembly has a top nozzle which not only can be readily removed from and replaced back on the fuel assembly as a unitary subassembly, but also can be readily disassembled and reassembled itself in order to repair or replace some of its own components. The top nozzle uses a plurality of reusable locking pins releasably mounted in bores defined in the sidewall of the top nozzle lower adapter plate. The locking pins, in being mounted in the bores, extend across slots formed in the sidewall and, in so doing, close the open upper ends of slots so as to prevent upward movement of elements on the upper hold-down plate lugs out of the slots and thereby prevent disassembly of the upper hold-down plate from the lower adapter plate.

Abstract: A nuclear reactor coolant pump impeller/shaft assembly, including an impeller nut with a plurality of conduits formed therein in fluid communication with both ends of a passageway formed in the impeller nut in contact with a portion of the shaft, the fluid inlet and fluid outlet of the pump. Due to this conduit/passageway combination, coolant is effectively pumped into the passageway to heat the shaft to a temperature approximately equal to that of the impeller, thus creating thermal balance of the pump's component parts and providing improved pump efficiency.

Abstract: Installation for electric connection of devices placed inside the containment of a PWR, comprising a first cable associated with each electric device, extending from the device and connected to a fixed connector installed above the cover of the reactor vessel. A second cable is connected to the connector and to a connector fixed to a plate remote from the reactor vessel. Each second cable is formed from several sections including a first section for connection to the fixed connector above the cover and to a lead-in connector at the end of a leak tight conduit installed horizontally above the cover and a second section inside the conduit. A third section is adapted for connection to a lead-out connector from the conduit and to the connector fixed to the plate at a distance from the reactor.