Abstract: An improved nuclear fuel assembly (10) of the type having a plurality of intersecting metal strips (14) welded at the strip intersections (32). At least some of the strips (16a, 18a) have nonlinear upper or lower edges (32a, 44a) at the intersections such that some of the intersection welds (34) at the strip upper or lower edges are at different elevations (34b) relative to intersection welds at other upper or lower edges (34a, 34c, 34d).

Abstract: An inproved grid (16) for a nuclear fuel assembly (10), having a plurality of externally projecting, integrally formed anti-bowing springs (50) spaced about the grid perimeter plate (26), for interacting with flat surfaces (52') on the opposite grids (16') of adjacent assemblies (10'). The anti-bowing springs (50) are horizontally separated along each grid (26) in periodic alternation with substantially flat portions (52) of the perimeter plate (26). Preferably, each grid has a plurality of primary anti-bowing springs (70) that project a distance at least equal to the nominal gap (g) between assemblies, and a plurality of secondary anti-bowing springs (72) that are stiffer but project less than the primary springs. Also, backup springs (74) are disclosed as integrally formed ridges adjacent to the anti-bowing springs. The interaction of each grid (16) with its neighbor (16') "tightens" the core during power operation and provides an anti-bowing effect.

Abstract: A two-speed stepper actuator unit for use in paper machine headbox slice lip control has a spindle 16 driven by a power nut 24. A lever clamp 32 has legs 34 and 36 selectively clamped together around nut 24 by means of a cam action locking plate 40 driven by solenoid 48. The longer leg 36 of clamp 32 has a cam follower which rotationally drives nut 24 through the lever 36 in response to the shape of a cam plate 50 which translates in the housing 12 on antifriction rollers 66 when drive solenoid 54 is actuated. The cam surface 60 guides the lever 36 in either of two speed modes depending on whether spring biased roller follower 52 is on cams surface portion 62 or 64.

Abstract: A wear-reduction-shield (40) for use between the core plate (24) and lower end fitting (26) of a pressurized water reactor (10) to reduce excessive wear of in-core-instrumentation thimbles (30) due to flow induced vibrations and resist fuel assembly tipping has a cylindrical body portion 42with core plate engaging lower end surface (44). At the opposite and upper end, a tapered internal end wall (46) assists upward threading of the monitor and cable. On the outside of the upper end symmetrical leg portions (52) and central land (54) surround a thimble (30) receiving opening (48). Smoothly tapering outer surface (56) minimizes turbulence in and beyond opening (34) in lower end fitting (26). Internal dimensions of shield (40) avoid structure such as sleeve (50) which may be present.

Abstract: A fuel element for a nuclear reactor having a zirconium tin alloy cladding tube, with a thin coating of enriched boron-containing alloy burnable poison, such as nickel-thallium-boron deposited from a reducing agent by an electroless plating process.

Abstract: A stabilized alpha metal matrix provides an improved ductility after irradation without loss of corrosion resistance in a "Zircaloy" alloy modified with measurable amounts of up to 0.6 percent by weight of niobium or 0.1 percent by weight of molybdenum. Tin is present in the Zircaloy in the range of 1.2 to 1.70 percent by weight and the oxygen level is in the range of from 1000 to 1600 ppm. Iron and chromium alloying element levels are those of typical Zircaloys. The average intermetallic precipitates' particle sizes are in the range of from 1200 to 1800 angstroms, thereby providing optimum corrosion resistance of the improved alloy in both boiling water and pressurized water reactors.

Abstract: Integral vanes 4 with optimized size, shape and bend angles maximize coolant mixing and fuel rod 12 heat transfer downstream. Recessed weld nuggets 5 with no vane cutout are optimized for size, strength and corrosion resistance. Staggered arches 20',22' and springs 20,22 minimize turbulence and reduce grid pressure drop and promote coolant mixing. Crowned arches 20',22' and springs 20,22 decrease scoring of fuel rods 12 and are sized to minimize turbulence and pressure drop. Minimum cutouts in unslotted section of grid strip 46,46' give 15-20% strength increase. Intermediate weld and tapered end slots 48 give 15% strength increase. Ribbed and round dimple stiffeners 38,39 on outer strips increase buckling resistance, reduce handling damage and spreads accidental loading. Outer strips 32 are optimized for strength, handling, turbulence generation and pressure drop. They also divert enough flow to interior of fuel assembly to match thermal power distribution and eliminate fuel rod corrosion concerns.

Abstract: A paper machine headbox slice lip rotector system which permits limited incremental movement up or down by means of a pivoting lever arm 32 with lock bolt end portions 36 and 38 moving in adjacent protectors' adjustable keeper recesses 40. The recesses 40 are defined by stop nuts 42 on a threaded body fixed to the adjustable spindles 20. The lever arm 32 is pivotally mounted on the body for permitting up and down movement a distance which is the average of the distance defined by the keeper recesses 40 of the adjacent protectors. This prevents the prior art problem of a protector being "locked" between adjacent protectors.

Abstract: A nuclear steam generator having anti-vibration bars for limiting the motion of spaced heat exchanging tubes is provided with a shim located between every n.sup.th tube where n is greater than 1. The shims have a thickness equal to n times the dimensional difference (x-y) of the distance x between a pair of tubes and the width y of an anti-vibration bar between the tubes. The shim is of channel-shape and is put in position by cutting and removing the wrap-around bars from the outside of the tube bundle, inserting and expanding a bladder to spread the pair of tubes in the bundle on opposite sides of an anti-vibration bar, moving the anti-vibration bar between the pair of tubes to one side of the opening created by the bladder, inserting a shim of modular links between the anti-vibration bar and one tube of the pair of tubes and repeating the bladder inserting, expanding and anti-vibration bar moving steps to insert shims at intervals n along the bundle.

Abstract: A nuclear steam supply steam generator primary nozzle 16 is sealed by a nozzle dam having segmented bulkhead portions 42 and 45 with peripheral flanges 46,50,52. A rubber diaphragm with a body 54 and peripheral strata form oppositely opening cavities 56 and 58. Hydraulic pressure from either side enters one of the cavities to create a radial sealing force against the inside surface of nozzle 16. A closed cell foam rubber sealing material 76 of 20 to 30 durometer can be interposed between the cavity defining strata and the surface 16 to improve sealing. A hinged retaining ring 70 is pinned to hold the nozzle dam against radial surface 68 machined in nozzle 16.

Abstract: A manipulator for a fiberscope probe or other inspection probe includes a fixed base 20 and a chassis 96 rotating on a hollow spindle 70 relative to the base. The chassis, spindle and an internal housing 66 rotate together with a translative motor 60 for powering a friction drive and the rotation providing motor 100. The friction drive wheels 26 and 28 oppose idlers 30 and 32 which are movable by means of a tensioner 74 to increase the friction of the drive mechanism. The friction drive wheels extend into a central passage 12 through which the probe passes to drive the probe. The rotation motor acts with a gear fixed relative to base 20 and is controlled through limit switches 122 and 124 for 400.degree. of rotation. A potentiometer 130 monitors rotational positions. An encoder 140, driven by an idler to eliminate slippage, monitors the friction drive of the probe.

Abstract: Two pressurized fluid system orifices in series (48,50), one (50) having a variable effective flow area (A.sub.2 ) provide a proportionate measurement of a gap (x) between a nuclear reactor vessel (12) and a core support barrel (20) by means of the variation of pressure in the intermediate chamber (44) between them. A transducer (T) or a pressure gage (P) senses the proportionate pressure.

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: An orbital weld head tool (10) has an orbiting and reciprocating carriage (22) for movement around a mandrel (12) fixed to a workpiece. Reciprocation is by a ball nut and screw drive means (70,74) driven by an arc voltage controlled motor (64). Rotation of carriage (22) with its ceramic shielded tungsten weld tip (16) and gas conduit (19) is by means of a separate motor (62) and drive belt (28). Power is supplied from a flexible hose connected through a conductive ball bearing assembly (30) and a conductive shoe (20) for weld tip (16) mounted on carriage (22).

Abstract: Apparatus and associated methods for measuring the polymer content of a mixture having polymer and cellulose components. Infrared absorption means are employed to derive a measurement of that fraction of the combined weights of polymer and cellulose components which is accounted for by the polymer.

Abstract: A feedwater sparger assembly, and more particularly a thermal sleeve device, to prevent relatively cold feedwater from contacting the vulnerable surfaces of a feedwater nozzle in a boiling water nuclear reactor. Inner and outer concentric tubular thermal sleeve members (42,56) span the distance between the sparger (12) and a substantially cylindrical transition surface (34) machined into the feedwater nozzle (14) or pipe (22). At the first ends (46,64) of the tubular members, adjacent the transition surface (34), a packing means (50), is deformed against the transition surface (34). The second ends (60,62) of the tubular members are operatively connected to the sparger (12). One of the tubular members (42,56) is rigidly connected to the sparger (12) and the other tubular member is mounted on the sparger such that it can be longitudinally moved relative to the rigidly connected member.

Abstract: A fuel assembly (10) has a lower end fitting debris collector (40) assembled in the form of a welded assembly of an "eggcrate" grid (21) and cast base (40) with hollow legs (42). Fastener seats (46) in hollow legs (42) permit guide tubes (14) with internally threaded ends to be joined to the upper surface of the lower end fitting debris collector (40) by means of slotted fasteners (50). Bevels (62) and notches (64) in the grid bars (26 and 24a, respectively), provide an embodiment with contoured seats for fuel rod end caps (22). Otherwise, end caps (22) rest on grid (21) at the intersection of slottedly interlocked bars (24 and 26). Thin strips (30) mounted in slots between bars (24) and bars (26) provide small debris catching openings in grid (21).

Abstract: A nozzle dam 14 has an integral diaphragm 50 and peripheral seal 58 radially engaged by bladder 46 to seal against the nozzle dam surface 12. The bladder receives force from a surface 44 on a plunger member 42. The plunger member 42 moves with the nozzle dam securing pin 32 as it seats in socket 40. A manual toggle type action clamp 20 actuates the pin 32.

Abstract: A fuel element for a nuclear reactor having a zirconium-tin alloy cladding tube, with a thin coating of particles of enriched boron-containing compound burnable poison particles, such as ZrB.sub.2 deposited from a liquid suspension which includes an acrylic polymer binder material and isopropanol. Graphite lubricant particles can be included in the coating.

Abstract: A tool having a rotating hollow electrode is provided power through a rotary electrical connection in the form of ball bearings and conductive lubricant, with a fixed hollow power supply fitting mounted in and insulated from a housing structure journaled in the bearings. Gas for welding is supplied through the hollow fitting and electrode which are in fluid communication.