Abstract: A method and an apparatus for measuring a tapered cylindrical object, such as a mandrel. The apparatus employs a linear positioning table assembly with a slide mounting for a laser micrometer, an axial position stepper motor for moving the laser micrometer stepwise along the axial length of the mandrel, and an angular position stepper motor for stepwise rotation of the object. The laser micrometer measures a cross-sectional diameter of the mandrel at a plurality of angular positions of the mandrel for each one of a plurality of axial positions along the length of the mandrel. The measurements taken at a plurality of angular positions constitute a circumference profile at that axial position. The circumference profiles at a plurality of axial positions constitute the contour profile of the mandrel. The acquired data are compared to desired mandrel contour profile data.

Abstract: A tool for checking the required spacing between adjacent fingers of the spud in a control rod drive. The tool is a GO-NO-GO gauge with tight tolerance. The spud finger gauge has two circular cylindrical pins of different diameter. One pin (i.e., the GO pin) has a diameter less than the required spacing between adjacent fingers of the spud. The other pin (i.e., the NO GO pin) has a diameter greater than the required spacing between adjacent fingers of the spud. The spacing is correct if the GO pin passes through the spacing and the NO GO pin does not.

Abstract: A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.

Abstract: A nuclear fuel bundle includes a square array of fuel rods each having a concentration of enriched uranium and plutonium. Each rod of an interior array of the rods also has a concentration of gadolinium. The interior array of rods is surrounded by an exterior array of rods void of gadolinium. By this design, usage of plutonium in the nuclear reactor is enhanced.

Abstract: Leaf-type springs are inserted into slots in an upper tie plate of a nuclear fuel assembly and bear against interior surfaces of the fuel channel to center the upper tie plate within the fuel channel. More robust similarly configured leaf springs are secured in slots in the upper tie plate and are cantilevered for bearing engagement through slots in the fuel assembly channel against the reactor top guide to bias the fuel assemblies toward the control rod. To mount each spring to the upper tie plate, the base of each leaf spring includes a central beam and a pair of outermost beams spaced from the central beam, all beams lying in a common plane. Laterally outwardly directed tabs are provided on the lower ends of the outer beams. Stops are provided intermediate the ends of the outer beams. By inserting the unstressed, unloaded base of the springs into the slots, the outer beams are displaced inwardly into a stressed condition.

Abstract: A method for ultrasonically inspecting a closely packed regular array of mutually parallel, uniformly sized and spaced rigid rods surrounded by a thin-walled metallic channel and immersed in a compressible medium. The method utilizes the properties of coherently scattered ultrasonic waves to identify rods which are defective, out of position or missing. A plane, monochromatic ultrasonic wave is transmitted toward the array of rods on one side thereof. Then an interference pattern produced on an opposing side of the array is detected. This interference pattern is the result of multiple scattering and diffraction of the plane ultrasonic wave during propagation through the array of rods. When the wavelength is comparable with the rod diameter and the rods are not too close together, scattering results in spatial relationships that produce an unusually large amount of wave penetration through the array in certain directions relative to the incident propagation vector.

Abstract: A stator frame for an electromagnetic pump includes a casing joined to a hub by a plurality of circumferentially spaced apart struts. At least one electrically insulated power crossover lead extends through the hub, through a crossover one of the struts, and through the casing for carrying electrical current therethrough.

Abstract: A unitary one-piece lower tie plate grid has a lower portion and an upper portion for supporting the fuel rods. The lower tie plate grid includes cylindrical boss portions arranged in square matrices for receiving the lower end plugs of the fuel rods. Web portions interconnect the boss portions along the sides of the matrices. The lower grid portion includes a plurality of openings which open into the flow spaces defined by the convex portions of the bosses and the webs within each square matrix of the upper portion of the tie plate. Coolant flows through the lower flow openings into the flow spaces for further flow upwardly about the fuel rods. The openings are defined by the convex lower portions of the bosses and webs, as well as projections which extend laterally inwardly from the convex surfaces of the lower boss portions toward a central region in the middle of the square matrix.

Abstract: A grapple is provided for use with a fuel bundle channel of a nuclear reactor wherein the channel is provided with a pair of gussets in opposite corners of an upper end of the channel, each gusset having a hole therein. The grapple includes a pair of lever arms, each provided with a lifting foot at a lower end of the respective lever arm. The lever arms are movable in opposite directions to a channel lifting position wherein the channel gripper of each lever arm is located under a respective one of the pair of channel gussets. The channel lifting foot of each lever arm includes a pair of laterally spaced lifting elements such that the lifting feet may engage the underside of the gusset on either side of the gusset hole. In addition, each channel lifting foot includes a secondary foot or slider captured between the pair of lifting elements.

Abstract: An apparatus for cleaning inlet mixers while they remain in their operating position within a nuclear reactor. A cleaning tool is inserted by remote control into the inlet mixer via a secondary inlet opening. Following insertion of the cleaning tool, the internal surfaces of the inlet mixer are cleaned with a waterjet created from an ultra-high-pressure source and directed by controlled positioning of a cleaning head having a nozzle which scans the cleaning waterjet across the surface to be cleaned. The cleaning system includes a nozzle cleaning tool, a throat/barrel/flare cleaning tool, pumping systems for supplying ultra-high-pressure equal to at least 20,000 psi and low-pressure water to an installed cleaning tool, a launching system located at the top of the opened reactor vessel for feeding the water conduits (power), control cables, monitoring cables (instrument) and cleaning tool into and out of the inlet mixer, and a computerized process monitoring and control system.

Abstract: A method for fabricating a composite cladding comprised of a moderate-purity metal barrier of zirconium metallurgically bonded on the inside surface of a zirconium alloy tube which improves corrosion resistance. The improved corrosion resistance of the liner is accomplished by suitable heat treatment of the Zircaloy-zirconium composite cladding to allow diffusion of alloying elements, notably Fe and Ni, from the Zircaloy into the zirconium, in particular, to the inner surface of the zirconium liner. This diffusion anneal reduces the undesirable tendency of zirconium liner to oxidize rapidly.

Abstract: A combined ultrasonic and eddy-current method and apparatus for non-destructively determining the liner thickness of a zirconium liner provided at the inner surface of a zirconium alloy nuclear fuel rod tube utilizes dimensional data acquired via conventional ultrasonic measurement techniques and impedance data acquired through electromagnetic techniques to calculate liner thickness in accordance with a specific formula. The apparatus utilizes a computer or programmable arithmetic unit with associated memory and I/O devices connected to electromagnetic and ultrasonic measurement subsystems. A particular eddy-current probe arrangement consisting of a differential coil pair is employed to obtain impedance measurements from the outside of the cladding tube. Calibrated reference impedance values for various different inner and outer tube diameters having a constant liner thickness are measured and retained in a memory.

Abstract: In a fuel bundle for use in the core of a boiling water nuclear reactor, part length rods having a tendency to reduce pressure drop are used in combination with spacers and spacer attached devices tending to utilize pressure drop to improve critical power. The addition of the part length rods has the advantage of lowering the pressure drop. Attached devices substantially increase the pressure drop. Exemplary spacer attached mechanisms for the utilization of pressure drop are set forth including vanes--preferably swirl vanes on the spacers, decreasing the spacer pitch to increase the total number of spacers in the upper two phase region of the fuel bundle, increasing the vertical height of the spacers, and increasing the thickness of the metal from which the spacers are constructed. Two classes of separation devices are disclosed for placement in the volume overlying the end of the partial length fuel rods.

Abstract: A passive and inherent shutdown heat removal method with a backup air flow path which allows decay heat removal following a postulated double vessel leak event in a liquid metal-cooled nuclear reactor. The improved reactor design incorporates the following features: (1) isolation capability of the reactor cavity environment in the event that simultaneous leaks develop in both the reactor and containment vessels; (2) a reactor silo liner tank which insulates the concrete silo from the leaked sodium, thereby preserving the silo's structural integrity; and (3) a second, independent air cooling flow path via tubes submerged in the leaked sodium which will maintain shutdown heat removal after the normal flow path has been isolated.

Abstract: A two part lower tie plate assembly is disclosed for use with a fuel bundle of a boiling water nuclear reactor. The two parts include a rod supporting grid section and nozzle section. Both the rod supporting grid section and the nozzle section are constructed asymmetrically. The rod supporting grid section contains one half of the total offset required for a D lattice lower tie plate and the nozzle section contains one half of the total offset required for a D lattice lower tie plate. When a D lattice lower tie plate is required, assembly occurs so that the offsets are additive. When a C lattice lower tie plate is required, assembly occurs that the offsets are subtractive. Assembly of the lower tie plate is provided be either bolting or welding. There results on single rod supporting grid and nozzle section components capable of assembly to fit either a C or a D lattice.

Abstract: A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives.

Abstract: A safe analytical technique for determining the concentration amount of dibutyl and monobutyl phosphate degradation products in the TBP-dodecane solvent used in solvent extraction processes. This method of chemical analysis eliminates the use of diazomethane, which is toxic and explosive, thereby providing a safer laboratory technique for routine analyses required to monitor production solvent extraction processes. The solvent sample to be analyzed is spiked with mass labelled, deuterated dibutyl and monobutyl phosphates, which act as internal standards. After adding a silylating agent, bistrimethylsilyltrifluoracetamide, the sample is injected into a gas chromatograph/mass spectrometer, which measures the ratio between the labelled internal standard and the naturally occurring material to obtain a quantitative result.

Abstract: A tool for removal of the internal bushings from a piston coupling of a CRD. The tool incorporates a spring-loaded and hardened collet supported on one end of a ram. The collet has a pair of arms with shoulders or projections which latch inside the internal bushing ring to be removed. The tool is inserted into the piston coupling from either end, depending on which internal bushing is to be removed. The tool is inserted until the latching shoulders or projections snap behind the radially inwardly projecting internal bushing, with the contact surfaces of the shoulders or projections in contact with a radial end surface of the bushing. The bushing can then be dislodged, from the inside out, by impacting the other end of the ram with a hammer.

Abstract: A gauge for ensuring that the uncoupling rod of a control rod drive is properly inserted in the center hole of the spud and not in one of the outer lobes, i.e., spud flow holes, which communicate with the center hole. The uncoupling rod is inserted in the spud. Then the gauge is placed on top of the spud with a centering ring protruding into the spud. The uncoupling rod is correctly installed if it is free to slide inside the gauge and the spud. The gauge is also provided with a ring to protect the spud during transfer of the control rod drive.

Abstract: A vapor of diethylzinc or dimethylzinc is reacted with water vapor to form very small particles of depleted zinc oxide which are entrained in the gas flow. In accordance with one version of the method, a spray nozzle is used to mix liquid diethylzinc with dry nitrogen to prevent combustion. The nozzle sprays the diluted diethylzinc into a chamber heated up to its boiling point of 118.degree. C. to completely vaporize the diethylzinc. The diluted diethylzinc gas is then reacted with water vapor to form a fume of very small zinc oxide particles entrained in ethane gas without combustion. A similar process can be used to convert dimethylzinc into depleted zinc oxide powder. In accordance with another version of the process, an inert gas stream is saturated with diethylzinc or dimethylzinc vapor by passing a dry inert gas through a vessel containing liquid diethylzinc or dimethylzinc. A second inert gas stream is saturated with water vapor in a similar manner.