Abstract: A system for loading nuclear fuel pellets into tubular fuel pins. The system includes means for locating a fuel pin in registry with a pellet channel to enable a pellet stack to be displaced lengthwise into the fuel pin. The pellet channel and the pin locating means are mounted on a common structure. Linear vibrator means comprise first driving means arranged to urge the common structure in a lengthwise direction, and second driving means arranged to urge the common structure in a substantially perpendicular direction, so that the common structure is driven in a closed loop. Sensing means provide a signal upon cessation of pellet motion upstream of the fuel pin locating means. Means operable in response to said signal automatically adjust the phase relationship between said first and second driving means to effect reverse motion of the pellets.

Abstract: Sludge-removing fluid lances are moved simultaneously toward the center of a tube bundle in a steam generator through diametrically opposite lance ports. Fluid-blocking suction dams are placed in the peripheral lane of the steam generator at diametrically opposite inspection ports from which fluid-entrained sludge is removed. All four of the ports are spaced apart by 90.degree.. Fluid-entrained sludge is blocked on the opposite sides of both suction dams, thereby preventing redeposition of sludge in previously cleaned areas of the tube sheet of the generator. The fluid flow rates of the lances are controlled to be equal to each other, and the rate of removal of the fluid-entrained sludge through each suction dam is controlled to be the same as the fluid flow rate of each lance. A separate flushing stream in the peripheral lane is not required.

Abstract: An auxiliary seal for preparing a reactor coolant pump for vacuum degasification of the reactor coolant system includes at least a pair of sealing segments. The sealing segments are composed of metal and have semicircular shaped bodies with attaching ears and an anchoring flange fixed thereon. The attaching ears extend radially outward from opposite ends of the sealing segment bodies. The ears on one segment body when aligned with and attached by fasteners to the ears on the other segment body draw the sealing segments together in releasably attached relation to one another and in sealing and clamping engagement about a shaft of the pump. The segment bodies also have interior and exterior circumferential recesses with O-rings therein which seal respectively with a portion of the pump shaft and a portion of a housing of the pump. The annular flange extends radially outward from the sealing segment bodies and is attachable to the housing portion for anchoring the seal segments thereto.

Abstract: A method and apparatus for reducing thermal stress in steam turbines having steam chests with a plurality of linearly-arranged valves controlling respective nozzle chambers. By crosstying selected pairs of the valves, and selectively admitting steam through the crosstie, transfers of the turbine from a full-arc admission mode to a partial-arc admission mode, and vice versa, can be made with a minimum temperature differential.

Abstract: An apparatus for the inspection of nuclear reactor fuel rods combined in fuel rod clusters with spaces therebetween in a fuel assembly includes test probes each being disposed at a different respective level along the fuel assembly. Fingers are each part of a respective one of the test probes. Ultrasonic test heads are each disposed on a respective one of the fingers. The test heads are inserted into the spaces between the fuel rods, and the insertion position of each of the test probes is corrected independently of the insertion position of the others of the test probes, before insertion of the test probes.

Abstract: The method consists in separating the worn-out steam generator (1) from the primary circuit, by sectioning the pipes (3, 5) in the vicinity of the steam generator pipework, withdrawing the worn-out steam generator, placing a replacement steam generator in position and welding the pipe work of the replacement steam generator to the primary pipes (3, 5). Topometric measurements are carried out on the replacement generator, on the worn-out steam generator (1) in position in its compartment (11) and in the compartment (11) after the removal of the worn-out generator (1). Comparison of the topometric measurements enables the replacement procedure to be determined, i.e., the number of cuts to be made on the primary pipes (3, 5), the modifications to be made to the supporting and positioning devices (8, 17) and the position of the chamfers for welding the pipes (3, 5) and the pipework of the replacement steam generator.

Abstract: An improved liquid jet pump for water is described in which the water issuing from the jet pump drive nozzle passes into a nozzle mixing chamber where steam is introduced to nozzle outflow. This steam, traveling in the same direction as and converging upon the liquid driving stream, is raised to high velocities. These uncommonly high velocities of steam are attained both as a result of passage through a converging/diverging nozzle and the action of condensation upon the passing liquid stream. The liquid driving stream is supplied at a temperature which promotes immediate condensation of the steam molecules of the high speed steam jet. A process of momentum exchange immediately occurs within the drive nozzle mixing chamber between the high-velocity steam and the parallel-moving slower liquid stream with momentum being transferred from the steam to the liquid driving stream.

Abstract: A riot shield comprising a planar shield member (1), and at least one handle (3,4), secured to the back of the shield member (1). Integral linking means (5,6), is provided on each of two opposing sides of the shield member (1) whereby the shield member (1) can be releasably interlinked with the integral linking means of a second riot shield.

Abstract: A fuel element support grid for supporting a plurality of nuclear fuel elements intermediate their ends has at least some of the pairs of intersecting and slottedly interlocked strips including pairs of intersecting integral fluid flow directing vanes along at least one adjacent edge of each of the strips of the pair. Welds attach the pair of vanes to each other thereby providing welded attachment of the strips. The welds may be at the intersection of the vanes remote from their areas of integral attachment to their respective strips or they may be adjacent to their areas of integral attachment to their respective strips. The strips may be bent to provide the strip function and the arch function within the same stream engaging profile as the strip alone presents.

Abstract: A reactor cavity dosimetry system and method in a nuclear power plant having a reactor vessel and a primary biological shield substantially surrounding the reactor vessel thereby forming a reactor cavity between the vessel and the shield, the system and method providing for remotely and repeatedly positioning a plurality of neutron dosimeters at preselected locations within the cavity, and for withdrawing the dosimeters for analysis thereof and replacing them at the same preselected positions. Assessment of the long-term effects of neutron irradiation on the vessel is enhanced by accurate and repetitive placement of the dosimeters.

Abstract: A hairpin spring for holding a fuel rod in a fuel assembly grid consists of a metal strip bent to form two mutually confronting legs arranged to be welded together locally. At least in a zone which bears on the other leg, one of the legs is U-shaped and straddles the other leg through a respective window of the grid. The legs of the U may be formed as appendices bent substantially at 90.degree.. The arms may also close up slightly so that the other leg can snap thereinto or flare for self-centering of the other arm.

Abstract: A pellet collating system includes a tray positioning station located adjacent a pellet collating line with a tray transfer robot located therebetween. The tray positioning station has mobile carts lodged thereat, some supporting pellet supply trays and others supporting pellet storage trays. Pellets on one supply tray and later placed on one storage tray are of the same enrichment. Pellet enrichments on some trays are different from on others. The collating line includes pellet input, work and output stations arranged in tandem. The robot is operable to transfer supply and storage trays one at a time to and from the positioning station and the respective input and output stations. An input sweep head is operable for sweeping pellets onto the work station from a supply tray on the input station. A gripping and measuring head is operable for measuring a desired length of pellets on the work station and then separating the measured desired length of pellets from the remaining pellets, if any.

Abstract: A recoil absorbing gun mount (A) is disclosed which includes an elongated base (20) with a widened stabilized front end (22). A rear (24) of the base is supported by an incline adjusting leg (30) adjusted by a star wheel (32). Clamping jaws (40, 42) carry resilient gripping pads (44, 46) to frictionally clamp a gun (10) in the mount. The clamping jaws are attached by means of a pivot (C) which allows the clamping jaws to pivot in a yaw direction (56) and a roll direction (58). The pivotal movement in two degrees of freedom allows a clamping space (48) to be adjusted to accommodate different shapes and sizes of guns. The pivot includes angled slots (40f, 42f) formed in clamping jaws (40, 42). These angled slots slide over an operator rod (60) so that jaws (40, 42) may pivot relative to the base. A reduced clamping force is applied at (66) which is reduced from the force applied by operator rod ( 60).

Abstract: A rod arraying system for nuclear fuel rods or burnable poison rods. A support structure positions a consolidation canister vertically to receive the rods. A rod loading pattern provides a gap between rods to allow projections to hold each rod in position. One or more rod arraying devices positioned vertically along and inclined toward the canister provide a triangular pitch loading configuration. A guide assembly slidably mounted on the mounting base of the rod arraying device has two guide plates with scalloped edges. The guide plates are offset relative to each other with one being cycled back and forth by an air cylinder to allow individual loading of fuel rods one row at a time. The inclined weight of the guide plates keeps them in position against the rods to prevent unwanted shifting of rods during the loading operation.

Abstract: Colloidal corrosion products which are referred to as crud are removed from nuclear reactor coolant streams by suspending zirconium oxide particles in the coolant stream. The crud will be attracted to the surfaces of the zirconia particles and caused to agglomerate thereon. Such zirconia/crud agglomerates may be readily filtered from the coolant. By providing scavenger particles which comprise active areas of zirconia on basically magnetite particles, after the crud is agglomerated to the active zirconia surfaces, the agglomerates may be removed from the coolant utilizing magnetic separation principles.

Abstract: A gun tube thermal shroud for reducing temperature gradients across the gun tube caused by asymmetric external and internal heat flux distributions, which includes an inner layer of high thermal conductivity extending about and along the gun tube in intimate thermal contact with the gun tube. In the preferred embodiment, this inner layer is formed of aluminum wire which is tightly wound about the gun tube and which is embedded in a thermally conductive flexible adhesive. The shroud also includes a middle layer of thermal insulating material and an outer layer of high thermal conductivity material, which may be formed in the same manner as the inner layer.

Abstract: A reactor cavity dosimetry system and method for deploying the system which includes a top access support stand. Having a generally rectangular frame assembly formed by a pair of cross members and a pair of frame tubes, the support stand holds the dosimetry in place as part of a continuous loop. The continuous loop is first fed through a U-shaped tube situated beneath the support stand, and coupled together by a chain support plug which is adapted for insertion within a hole formed in an upper one of the cross members to fix the position of the dosimetry axially with respect to the core of a nuclear power plant within which the system is deployed. Each of the frame tubes has mounted thereon a pivotable arm assembly with a spring-loaded slide. After insertion within the cavity, the arm assemblies are pivoted out from the plane of the frame assembly, and disposed locked in place perpendicularly across the cavity.

Abstract: A bimetallic spacer for supporting fuel rods in position in a nuclear reactor fuel assembly substantially comprises inner and outer structural elements of a first metallic material and spring elements of a second metallic material. The structural and spring elements together define a lattice, the interstices of which receive the individual fuel rods. The structural elements and spring elements in the spacer are connected together by forming the structural elements with openings and fitting the ends of the spring elements in the openings. At one end of the opening in the structural element, two slots can be provided for forming a tongue-shaped member which is moved aside to make space for the spring element and then moves back when the end of the spring element is in position, thus preventing a possible vertical return movement of the end of the spring element.

Abstract: A container for a liquid radioactive and/or fissionable substance includes an outer container. An inner container is disposed in said outer container for receiving the substance. The inner container includes a primary container and a separate, closed secondary container having upper and lower ends. The primary container has an upper end protruding beyond said upper end of said secondary container and a lower end protruding beyond said lower end of said secondary container in longitudinal direction. A first connecting tube leads continuously downward in a direction from said lower end of said secondary container toward said lower end of said primary container. A second connecting tube leads continuously upward from said upper end of said secondary container in a direction toward said upper end of said primary container. The outer container has a fill chamber disposed therein for filling with heat-conducting filler.

Abstract: A nuclear battery in which the energy imparted to radioactive decay products during the spontaneous disintegrations of radioactive material is utilized to sustain and amplify the oscillations in a high-Q LC tank circuit is provided. The circuit inductance comprises a coil wound on a core composed of radioactive nuclides connected in series with the primary winding of a power transformer. The core is fabricated from a mixture of three radioactive materials which decay primarily by alpha emission and provides a greater flux of radioactive decay products than the equivalent amount of a single radioactive nuclide.