Abstract: A medium power, high temperature pebble bed nuclear reactor, which includes a means for introduction and withdrawal of operating elements. The installation is provided in such a way that it can be more economically built and operated. The installation includes several input stations above a prestressed concrete pressure vessel, and charging hatch blocks positioned on top of the prestressed concrete pressure vessel. The blocks include selectors through which the pebble-shaped operating elements, after traversing helical and meandering charging conduits, reach into the reactor core. The selectors and charging conduits are installed within armored ducts which penetrate the prestressed concrete pressure vessel. Similar armored ducts are provided for exit ducts for withdrawal of pebbles from the core, and a first common exit hatch block is connected to the exit ducts. The block is arranged within foundation walls which support the prestressed concrete pressure vessel.

Abstract: An apparatus for moving an object in an isolated environment may be employed as a high pressure and temperature facility for testing steam generator tubes. A tube to be tested extends through an opening in a plate that is mounted in a test vessel. The vessel is partially filled with water having selected contaminants, and heated water under high pressure is circulated through the tube to raise the temperature and pressure within the vessel. A lever arm having an inner end and an outer end extends through an opening in the test vessel. A vibration-coupler connects the inner end of the arm to the tube under test, and a fulcrum-former operationally connects an intermediate portion of the arm to the test vessel. The outer end of the lever arm is connected to a plug element which is shaken, so that the arm pivots about a fixed point at the fulcrum-former and the vibration-coupler moves the tube under test with respect to the plate.

Abstract: Shielding for technicians working around a nuclear reactor during the refueling process is provided by permanently mounting a shield support around the reactor shroud and temporarily hanging shielding members such as lead panels from the support. The shield support includes a permanent rail encircling the shroud and swingout arms which are pivotably mounted to the permanent rail. During use the shielding members are positioned adjacent the swingout arms by a stud tensioner hoist, and the swingout arms are pivoted outward to receive the shielding members. When installed, the edges of the shielding members overlap.

Abstract: An apparatus for repairing a protruding portion of an outer grid strap spring includes a support frame made up of interconnected members defining a generally rectangular opening and a plurality of devices mounted on the frame members above and below the frame opening for attaching the frame to the outer strap of the support grid. At least some of the devices are adjustable for securing the frame in a stationary position on the outer strap so that the frame opening is stationarily aligned with the outwardly protruding spring on the outer strap. A pair of spaced apart rails attached to the members on upper and lower sides of the opeing define a guide channel therebetween which extends along the opening in a first direction.

Abstract: A neutron streaming shield comprising a plurality of wire mesh baskets, each basket located between two adjacent vessel nozzles, the total area of the nozzles and baskets being sufficient to intercept any streaming neutrons. The baskets are substantially filled with a multiplicity of randomly packed lumps of a neutron attenuating material, preferably a borated-hydrogenated-argillaceous media. Since the basket is somewhat flexible, it can be inserted in the annulus above the nozzles and then filled with the lumped material, forming a plurality of barriers to compliment the attenuating affect of the nozzles, such that any streaming neutrons will be stopped either by the nozzles or the lumped material in the baskets.

Abstract: A method and an apparatus for loading containers with individual fuel rods r fuel-rod sections of irradiated nuclear reactor fuel elements are disclosed. In order to ensure maximum safety, cleanliness and close packing when loading the containers, the fuel rods or fuel-rod sections are horizontally front-loaded into the container which is horizontally positioned. The loading aperture is located as closely as possible to the upper inner periphery of the container. Following their insertion, the fuel rods or fuel-rod sections will drop onto the inner wall surface of the container or onto the already existing pile of previously loaded fuel rods or fuel-rod sections. The container for loading with such a method has a loading aperture in the end wall thereof arranged close to the inner periphery thereof for insertion of the fuel rods or fuel-rod sections.

Abstract: A fuel transfer system for transferring fuel assemblies through a transfer tube between fuel exchange locations respectively in a fuel storage and handling building and a containment structure of a nuclear reactor includes a segmented track comprising first, second and third track segments and a segmented drive screw comprising first, second and third drive screw segments respectively associated with the fuel storage and handling building, the transfer tube, and the containment structure. Gaps between the successive, corresponding track segments and drive screw segments permit operation of valves for closing the ends of the transfer tube during normal operation of the reactor, which valves are then opened during fuel exchange operations. The adjacent but normally displaced ends of the first and second and of the second and third drive screw segments include respective, mating engagement means.

Abstract: A canister for the consolidation of nuclear fuel rods (22) comprises an elongated, tapered box (24) of generally rectangular cross-section having upper (42) and lower (44) internal sections, the upper section having rectangular grid structure (46) and the lower section having vertically extending plate members (48). The upper section receives individual fuel rods in a relatively loosely packed rectangular array of rows and columns and urges the rods closer together as they are lowered into the box, such that the rods emerge through the lower end of the grid section in a relatively tightly rectangular array. The number of plate members (48) in the lower section corresponds to the number of rows of fuel rods in the upper section. Each plate has tapered side edges (204) abutting the tapered box, and a plurality of integrally formed, corrugated channels (206) corresponding to the number of rows of fuel rods.

Abstract: Fuel handling apparatus for transporting fuel elements into and out of a nuclear reactor and transporting them within the reactor vessel extends through a penetration in the side of the reactor vessel. A lateral transport device carries the fuel elements laterally within the vessel and through the opening in the side of the vessel, and a reversible lifting device raises and lowers the fuel elements. In the preferred embodiment, the lifting device is supported by a pair of pivot arms.

Abstract: A refueling machine (100) is provided with a latching/unlatching rod (116) which is provided with a hexagonally configured head portion for mated engagement with a hexagonally configured socket (34) defined within a latching/unlatching screw (22) of a fuel assembly (10) whereby the fuel assembly (10) may be securely mechanically connected to the lower core support plate of the reactor internals. The latching/unlatching rod (116) is fixedly connected to a housing (118) which is co-axially disposed within a torque tube (140), the latter of which is fixedly secured to the lower end of a spur gear (130). The spur gear (130) is rotatably engaged with a drive spur gear (148) through means of an idler gear (128), whereby torque is transmitted to the torque tube (140).

Abstract: A nuclear reactor refueling system for a liquid metal-cooled fast breeder reactor includes a large rotatable plug (18) eccentrically mounted relative to the reactor core (12), and a small rotatable plug (24) mounted within the large plug (18). A fuel handling machine (28) is rotatably mounted upon the small plug (24), and the eccentric mounting of the large plug (18) permits the fuel handling machine (28) to access all areas of the reactor core (12) as well as a fuel transfer station or port (34) located externally of the reactor core barrel (16) yet internally of the reactor pressure vessel. A unique six-fingered star-shaped upper internals structure (36) is eccentrically mounted upon the large plug (18) so as to be concentrically disposed relative to the core (12) when the reactor is in operation yet permitting access to the central-most fuel assemblies (14) of the core (12) as the large rotatable plug (18) is rotated during refueling operations.

Abstract: A method for reconstituting a nuclear reactor fuel assembly having its top nozzle adapter plate welded to its control rod guide thimble sleeves. Circumferentially cut the sleeves from the adapter plate below the weld. Separate the top nozzle from the cut sleeve 5. Obtain a modified top nozzle refashioned with a groove in its adapter plate control rod passageways. Insert the cut sleeves in the passageways of the modified top nozzle. Circumferentially bulge the sleeves into the grooves. A system for attachment of the top nozzle to the sleeves employing the above-described circumferential bulge and groove attachment.

Abstract: Magnetic actuators with dogs for positioning regulating rods in a nuclear reactor. The dogs (2) for lifting and/or holding the control shaft (1) are provided with at least two teeth (4) separated by a distance equalling that separating two successive grooves (3) of the shaft (1).

Abstract: A method and means of non-invasively determining the liquid level and density in a nuclear power reactor pressure vessel is disclosed. In general the method consists of detecting neutron levels external of the pressure vessel at least at positions adjacent the bottom of the fuel core, the center of the fuel core and the top of the fuel core; and the detected neutron level signals are directed to monitoring means.The detecting means may comprise fission chambers and monitoring means may comprise simple electric meters.

Abstract: A quick release guide sleeve assembly comprises an outer sleeve, an inner sleeve axially slidably received in the outer sleeve and having first and second axial positions with respect to the outer sleeve; and a locking mechanism movably mounted on the outer sleeve for frictionally engaging wall surfaces defining an opening for receiving the outer sleeve. The locking mechanism has a locking position in which at least part of the locking mechanism projects radially outwardly beyond the external circumferential surface of the outer sleeve. The locking mechanism further has a releasing position in which the locking mechanism is in a radially inwardly withdrawn state relative to the circumferential surface of the outer sleeve.

Abstract: A device for evacuating, filling and closing final storage containers for radioactive materials mixed with molten glass, comprising a suction pipe connected to the container, a meltable closure for said pipe and a closable evacuation connection fitting mounted in said meltable closure. The container is evacuated through the fitting whereupon the fitting is sealed closed to preserve the vacuum. When the suction pipe is dipped into the molten glass to fill the container, the closure melts and with the glass is sucked into the container.In another form the device also includes a protective sleeve surrounding the fitting, closed at its outer end with a meltable plate which also serves as a heat radiation shield. The shield prevents premature melting of the meltable closure, i.e. melting from the heat in the glass furnace prior to immersion of the suction pipe in the molten glass.

Abstract: Nuclear power station, including a containment for enclosing activity-carrying components having a given height and upper and lower parts, pipelines being extended in vertical direction in the containment over at least half of the given height thereof from the upper part to the lower part of the containment for mixing a gas atmosphere in the containment, the pipelines having an open top and bottom and an outlet in the lower part of the containment, a transporting device for mixing the gas atmosphere in the containment in the form of a blower connected in the pipelines for transporting gas from the upper part to the lower part of the containment in the pipelines, and a recombination device connected downstream of the blower in the pipelines for shunting the outlets thereof in the lower part and for targeted oxidation of free hydrogen within the containment.

Abstract: A nuclear reactor fuel assembly having an improved attaching structure for removably mounting the top nozzle on the upper ends of the control rod guide thimbles. The attaching structure includes an outer socket defined in the adapter plate of the top nozzle, an inner socket formed on the upper ends of the guide thimbles, and a removable locking tube that is inserted in the inner socket to maintain it in locking engagement with the outer socket. The outer socket is in the form of a complement of special shaped bores having an annular groove. The inner socket is in the form of a sleeve having its lower end attached to the upper end of the guide thimble and with its upper end provided with a circumferential bulge which seats in the annular groove. Three elongated slots are provided in the upper end of the sleeve to permit inward elastic collapse of the slotted portion so as to allow the larger bulge diameter to be inserted through the bore of the adapter plate and expansion into the annular groove.

Abstract: Nuclear power plant with a reactor building, a fuel building, buildings for the ancillary nuclear, electrical and safety equipment, and a building for turbo-electric machines.The group of buildings is in the general shape of a T, with the fuel and ancillary equipment buildings (2) and (3) in line at both sides of the reactor building, and the engine building (6) facing the reactor building (1) and perpendicular to the latter. The vault of the protective enclosure is connected to the foundation of the reactor building and is in the shape of a cylinder with horizontal generatrices.The invention is applicable to light water nuclear power stations.

Abstract: The shroud is designed to prevent components of a damaged nuclear fuel element from dropping into a pool. The shroud consists of a body 1 surrounding the nuclear element over the major part of its height, and a base 2 equipped with a device to attach it to the feed 13 of the fuel element. The attaching device is actuated by the rotation of a control shaft 17 capable of being inserted in the center of a hub 9 equipped with two arms 10, which carry at their ends gripper fingers 11, maintained in their position of engagement in the feet 13 by springs 20.