Abstract: A pressurized water reactor fuel assembly (10) has a fastener or bolt (40) of stainless steel with a longitudinal groove (48) attaching zircaloy guide tubes (16) to stainless steel lower end fitting (14). The guide tubes have internally threaded zircaloy plugs (52) for mating with the threads (46) of bolt (40) with points (50) created in the threads (46) by groove (48) providing increased friction. The groove (48) acts to accommodate stresses set up by differential thermal expansion of zircaloy and stainless steel. Apertured stainless steel cups (60) receive the plugged ends of guide tubes (16) to capture them and provide connections to lower grid (22) of stainless steel.

Abstract: An apparatus (10) and a method for applying a chromized coating (46,60,62,66) to one or more of the surfaces of an article (44,56,58,64) particularly in those situations in which the article (44,56,58,64) is intended to be employed in an application wherein the article (44,56,58,64) will be subject to corrosion.

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, deposited from a liquid sol-gel which includes a glass binder material.

Abstract: A wear-reduction-sleeve for in-core-instrumentation thimbles of a pressurized water nuclear reactor having bottom mounted instrumentation to curtail flow induced excitation and increase support contact area in the region of thimble length which extends through and defines an annulus with the core support plate and extends upwardly to and through the fuel assembly flow distribution plates. The wear-reduction-sleeve includes a hollow shank portion which gives a low wear coefficient when in contact with the chrome-plated thimble and is inserted into the annulus and below where it is radially expanded and secured to a thimble guide tube. An upper portion of the wear-reduction-sleeve between the core support plate and flow distribution plate has a flow collection chamber and radial flow exit slots which divert thimble flow substantially away from the hole in the fuel assembly flow distribution plate through which the thimble extends.

Abstract: A welding apparatus (10) for longitudinally traversing and circumferentially welding within the interior of a tube. A rotating weld tip and gas supplying containing head is mounted on and rotationally driven by a rotor tube (36) extending from the end (90) of a cylindrical housing (12) in which it is mounted. The axially fixed rotor (36) is surrounded by and is driven by a helix drive connection (52,54,56) to a piston (20). The piston (20) reciprocates in a cylindrical bore (14) within the housing (12) in response to selectively applied fluid pressure acting against a spring bias (26). A strain gage (72) on the spring (26) controls the fluid pressure by means of valve ("V") whereby reciprocation of the piston (20) rotates the rotor (36) by means of the helical groove (52) and balls (54). The various parts are hollow to accommodate the necessary wire conductors (70,86) and gas flow.

Abstract: A tool 10 for creating a standard repeatable impact on a nuclear steam supply system (NSSS) structure to determine the response of an accelerometer to the impact of a known energy at a predetermined location on the structure. The tool 10 includes a barrel 12 and a spring 30 which biases a ram 20 reciprocally mounted in the barrel and driven by cam plates 66 and 68 on shaft 60. A flange 28 on ram 20 compresses spring 30 and upon movement of follower 72 to a maximum radial distance from shaft 60, the follower 72 drops down step 70 on the cam surface to allow spring 30 to uncompress and project ram 20 out of the barrel such that end 22 of the ram creates a standard impact on the NSSS structure. A hand crank drives shaft 60. A dampening spring 78 assists in the rebound of the ram 20.

Abstract: A chromium coating process for coating large size articles such as boiler tubes and boiler tube assemblies, comprises the steps of: (a) mounting on a stationary foundation a retort having a removable cover; (b) covering the articles to be coated in the retort by a chromium source powder containing 3% of ammonium chloride and 42% ferrochromium, the balance consisting of alumina; (c) sealing the cover on the retort; (d) heating the retort to a uniform temperature of 2100.degree. F. for 10 hours; (e) supplying concurrent with the commencement of the heating an inert gas to the interior of the retort; (f) terminating the heating of the retort and shutting off the flow of the inert gas to the retort; (g) cooling the retort and the articles within the retort uniformly throughout to a temperature of 400.degree. F.; (h) removing the cover from the retort; (i) removing the coated articles therefrom.

Abstract: A system and method for installing a nozzle dam unit (26) in a nuclear steam generator having a head (12) including a head internal surface, a manway (14) penetrating the head, and a nozzle (16) penetrating the head. The system comprises a manipulator (76) adapted to be passed through the manway and having one end (82) adapted to be attached remotely to the head internal surface and a free end including a clamp member (104). A plurality of nozzle dam segments (54, 56, 58) are each sized to pass through the manway and carry means thereon (120) for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle. The manipulator is controlled so that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then is translated within the head until the dam subassembly seats within the nozzle.

Abstract: A gap sensor comprising a C-type core (38, 62, 126) wrapped with a coil (44, 68, 130), and arranged to be responsive to the variable reluctance in a magnetic circuit passing through the core, two refiner plates (28a, 28b, 194, 198) and the gap (34, 90) between the plates. The two sensing ends (134, 136) of the transducer core legs (128, 132) are positioned in close proximity to the circumferential surfaces, or rims (82, 86, 212, 214) of the two spaced apart refiner plates, respectively. The magnetic field generated by the coil follows a magnetic path or circuit including the core (38), the radial gaps (46), between the sensor and the discs (16, 18), the refiner disc material, the plates (28a, 28b) mounted on the disc, and the clearance gap (34) between the two refiner plates.

Abstract: A method of repairing leaky compression fitting seal joints between a pressure stub tube (22) projecting from a nuclear reactor head (12) and a cylindrical thermocouple body (24) concentrically mounted in the stub tube (22) for penetration of the reactor pressure boundary. The method includes the steps of loosening and disassembling compression fitting nuts (30,32) and fitting body (34) to expose, and remove by grinding, a cammed ferrule radial compression means (26,28), cleaning the surfaces to be sealed, axially telescoping a split collar (40) between the tube (22) and the thermocouple body (24) and providing split rings (44,46) of brazing material surrounding the thermocouple body adjacent the exposed ends of the tube (22) and the collar (40). Resistance heating the tube and, therefore, the brazing material and repositioning and reassembling the fitting body (22) and fitting nuts (30,32) to complete the repaired seal joint.

Abstract: A camera is mountable near the target for generating a composite video signal including the target and a region extending along a predetermined direction from the target. A video signal converter is associated with the camera, for separating the video signal into horizontal and vertical digital data points associated with arbitrary horizontal and vertical axes in the camera. The horizontal data points and the vertical data points are spaced apart by a horizontal unit pitch and a vertical unit pitch, respectively. One of the arbitrary axes is aligned with the predetermined direction of target movement, and calibration establishes a quantitative relation between the unit pitch of the video signal data points along one aligned axis and a known distance along the predetermined direction. The number of digital data points are counted between a reference position of the target and a displaced position of the target on the aligned axis, which is commensurate with the displaced position of the target.

Abstract: A permanent magnetic filter is provided in a form that includes a closed vessel having an inlet plenum, a central filtering region, and an exit plenum. The central filtering region includes a plurality of magnet filter tubes arranged in a substantially uniform array that is supported in a manner which achieves satisfactory filtering, minimizes fluid pressure drop, and permits easy cleaning.

Abstract: Calibration of an eddy current probe (24) and associated data acquisition and analysis system (42, 48, 52, 54, 66) is accomplished using a step tube sample (68) having a nominal diameter portion (74) substantially equivalent to a nominal field tube (22). Two readings of eddy current test units are obtained from the step tube sample, and the diameter of the probe is used as a boundary condition on the non-linear response of the probe to variations in tube radius. A calibration curve is generated for use in converting field tube eddy current measurements to field tube radius or profile.

Abstract: A radiation reducing door assembly comprises a mounting bracket having hinge means affixed thereto, said hinge means defining different axes of rotation for doors of at least two types, the doors being sized and shaped to overlie at least a portion of the opening with which the assembly is associated. The door assembly also includes means for rotatably coupling the removable doors to the hinge means whereby the mounted door is supported from said bracket and may be pivoted between open and closed positions.

Abstract: A self-cleaning filtering apparatus is provided comprising a body with an inner filtering basket communicating with an intake duct for the product to be filtered and a drain for discharging waste and forming, with the body, a peripheral space communicating with an outlet duct for the filtrate. Rotary scrapers clean the inside of the basket. The peripheral space communicates with the filtrate outlet duct through an annular restriction.

Abstract: The disclosed method includes the steps of positioning an ultrasonic transmitter (50, 52) on the exterior body portion (54) of the valve (14), oriented so that the transmitted ultrasonic wave intercepts the path (46) of the closure member (30) at least at one location, and positioning an ultrasonic receiver on the body portion oriented to detect reflected ultrasonic waves when the closure member passes through such location. The valve body (20) is filled with water and the closure member is caused to move along the path. The transmitter and receiver are operated to generate an output signal trace (64) commensurate with the magnitude of the ultrasonic wave reflected from the closure member at the targeted locations along the path.

Abstract: A fuel assembly (10) has a lower end fitting debris collector and end cap spacer grid (20) 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 (20) by means of slotted fasteners (50). 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). Thick strips (30a) project upwardly between strips (30) to limit lateral movement of the end caps. Projections (70) on bars (24) prevent axial fuel rod movement by engagement of tab (70a) in circumferential groove (23) of end caps (22). Opposing capture force is provided by a wire (72) which is supported in openings in thick strips (30a) and which is received in groove (23).

Abstract: The steam generator water level, the feed water temperature, and the reactor power are continuously measured and a level signal (76), a temperature signal (78), and a power signal (80) commensurate with these measurements are respectively generated. From the power signal and the temperature signal, a target flow signal (84) is generated corresponding to the feedwater flow rate that would produce a stable steam generator water level at the steady state condition of the power signal and the temperature signal. The level signal is compared to a level signal setpoint (54) and a resulting level error signal (86) is generated. The level error signal is adjusted by a gain factor (88) that is dependent on the temperature signal to produce an adjusted level error signal (90). The feedwater flow through the bypass valve is then controlled in response to the target flow signal (84') and the adjusted level error signal.

Abstract: Wet stream is extracted isokinetically through a steam sampling nozzle and is directed, preferably vertically, through a moisture separating and divider unit (24) having a center tube (84) coaxially disposed in a substantially cylindrical shell (20), and a helical swirling device (98) coaxially located within the tube, which imparts centrifugal motion to the wet steam. As the steam passes through the helical device, the separated moisture droplets are drawn off from the vapor through holes (92, 94) in the periphery of the tube and fall to a liquid accumulator volume (26) in the shell. The extracted vapor is passed out of the shell to a measurement station including an orifice plate or venturi. Sensors (48, 50) are provided in the shell accumulator volume, to measure directly or indirectly, the mass of water extracted from the moisture separator. Similarly, the orifice plate and associated sensors (36, 38), measure the mass of vapor in the steam from which the liquid was extracted.

Abstract: An arrangement for temporarily sealing the space between two substantially parallel, adjacent plates in which a flexible, partially inflatable seal is located between the plates to effect primary and secondary sealing interfaces along the upper and lower edges of the plates, respectively. The seal has a wedge-shaped upper portion, a tubular lower portion and a substantially solid intermediate shank. The tubular end of the seal is inflated so that it expands into contact with the lower edges of the plates, drawing the wedge-shaped upper portion of the seal toward the tubular portion, thereby forming primary sealing interfaces between the wedged-shaped portion and the upper edges of the plates. The contact of the inflated tubular portion with the lower edges of the plates forms secondary seal interfaces. The effectiveness of the seal can be tested by measuring the pressure in the chambers formed between each set of primary and secondary sealing interfaces.