Abstract: A method of measuring the duration of a selected pulse in a pulse train produces a pulse count enable logic signal in response to a start pulse to enable a first down counter to count transition points in the pulse train. The pulse count enable logic signal has a duration at least as long as two sequences of pulses in the pulse train. The first down counter counts down from a predetermined initial count representative of the selected pulse in the pulse train and enables a second counter when the count corresponding to that selected pulse is reached. The second counter is used to count high speed clock pulses until the end of the selected pulse in the pulse train. The final output count of the second counter is then used to calculate the duration of the selected pulse.

Abstract: An improved method and apparatus for preventing electrical shorts between sets of stator coil headers and accompanying connections is disclosed in which a reinforced, non-conducting cover is fitted over a pair of stator coil headers, or a stator coil header and an adjacent phase connector. Thereafter, the cavity formed by the fitted cover can be filled with an insulating, solidifying or polymerizing material or resin. Use of such an apparatus insulates the entire header apparatus and prevents any accidental shorting between sets of stator coil ends.

Abstract: Gas diffusion oxygen cathodes, oxygen consuming electrochemical cells utilizing such cathodes, and a method of preparing such cathodes are disclosed. The cathode comprises an electronically conductive porous body defining respective gas and electrolyte contacting surfaces. The cathode is prepared by forming the porous body, disposing the electrolyte contacting the gas contacting surface with a gaseous atmosphere. Current is passed through the porous body at a degree of electrode polarization much higher than normal whereby modification of the electrode material is effected. If desired, a transition metal macrocycle catalyst may be incorporated in the electrode and is subjected to pretreatment as well. The inventive electrodes exhibit superior voltage performance under oxygen reduction polarization conditions.

Abstract: A motor controller or contactor is disclosed which utilizes a non-saturating current transformer for sensing the amount of current flowing in the electrical conductor connected to the contactor. The current sensor is made of homogeneous sintered powdered metal having evenly distributed microscopic air gaps therein which increase the reluctance of the magnetic circuit but resist the influence of stray magnetic flux. This increased reluctance prevents magnetic saturation over a wide range of input current and allows the secondary of the transducer to produce a voltage which is proportional to the derivative of the primary current, that is the current being sensed by the transducer. The aforementioned voltage is linearly proportional to the derivative of the current over a wide range of primary current values. This voltage is integrated to produce an output signal which is directly proportional to the aforementioned primary current over the wide range of current values.

Abstract: A reactor vessel O-ring spring clip designed to hold the tubular O-ring in the groove of a reactor vessel head flange, especially during head lifting. The spring clip is designed such that the weight of the O-ring acts to increase the friction force between the spring clip and the, typically, threaded hole into which it is inserted. The end of the clip adapted to be inserted through a slot in the tubular O-ring for securement thereto has a circular member thereon which prevents the spring clip from becoming disengaged from the O-ring during head lifting.

Abstract: An apparatus for holding a superconducting cable comprising a support structure having grooves and a slot that receives the cable. The apparatus is also comprised of at least one cable retaining clip. The clip is fitted into the grooves and held thereby such that the clip retains the cable in the slot and in contact with the support structure. In a preferred embodiment, the clip and the support structure are made out of different materials with the clip made of a material that has a lower coefficient of thermal expansion that the material of which the support structure is made.

Abstract: Apparatus for monitoring an object piece of qualified equipment in a nuclear power plant includes first passive means for memicking the effect of radiation received by the object piece, second means for mimicking hte effect of a thermal history of the object piece, and means for mounting the first and second mimic means in close proximity to the object piece in the nuclear power plant. In order to generate and maintain evidence to assure that qualified equipment used in such stations will operate on demand, the first and second mimic means, mounted in close proximity to the object piece, are exposed to the environment of a normally operating power plant and periodically analyzed to determine whether the qualified life of the object piece may be extended.

Abstract: Methods and apparatus for preventing swirl in a stem turbine having an annular-shaped stationary portion through which extends in regions of differential pressure a rotatable shaft include flow dams situated perpendicularly with respect to a plurality of spaced-apart annular teeth which extend radially inward from the stationary portion toward the shaft to within close proximity thereof, each adjacent pair of teeth forming a cavity there between. By damming the cavities, a circumferential stem flow is substantially minimized, thereby preventing the conditions necessary for the inducement of swirl.

Abstract: A nuclear fuel assembly having an array of longitudinally extending fuel rods and axially spaced transverse grids with cells receiving the fuel rods therethrough employs anti-fretting protective devices for protecting lower end portions of tubular claddings of the fuel rods from damage-inducing contact with debris entrained in upward flow of coolant through the fuel assembly. Each device is in the form of a hollow sleeve disposed about and extending coextensive with the lower end portion of one fuel rod cladding. The sleeve has an upper portion which extends through one grid cell between lower and upper ends thereof, and a lower portion which extends below the grid cell from the lower end thereof to a bottom end of the fuel rod cladding spaced below the grid cell lower end.

Abstract: A frequency selective limiting device is described incorporating a planar ferrite member and at least one signal-carrying conductor positioned thereon. A conductor is located on the ferrite member to confine a portion of an RF magnetic field produced by the microwave signals within the ferrite member. In one embodiment of the invention, the conductor comprises coplanar ground planes positioned adjacent to the signal-carrying conductor, thereby forming a coplanar waveguide. Alternatively a pair of coplanar conductors may form a slot line. In another embodiment a second ferrite member is positioned in confronting relationship with the first ferrite member carrying the conductors.

Abstract: A wiring device of the type which by itself is configured for surface mounting is made more universally mountable by an adapter plate to which the device may be joined and the adapter plate joined to any of a number of different outlet box configurations. In addition and alternatively, a wiring device so described may be further utilized with a portable box on which it is mounted, which portable box has sidewalls with cord openings communicating to the device. All such configurations are designed for compactness and shallowness from a front face which may provide a plurality of outlet openings. In addition, the wiring device of the present invention utilizes a snub hole wiring termination configuration that facilitates installation.

Abstract: Measurement of lengths for determining the outside diameter, wall thickness or inside diameter of tubes which, must be maintained to close tolerances. A mandrel of tungsten carbide having a coaxial projection of knife-edge width is postioned so that its transverse dimension intersects the beam and is parallel to the plane of the beam. A first length is measured between the end of the beam and the nearest point on the projection. A tube is mounted on the projection with its its longitudinal axis parallel to the longitudinal axis of the mandrel and its inner surface engaging this. A second length is measured from the end of the beam and the nearest point on the tube. The outside diameter is measured on the shadow of the tube produced by the laser between the shadow of the nearest point and the shadow of the most remote point from the end of the laser beam. The wall thickness is equal to the first length less the second length. The inside diameter is the outside diameter less twice the wall thickness.

Abstract: A system for real beam radar ground mapping using a monopulse antennae to determine off-boresight angle of target returns. Off-boresight angle is converted to azimuth bins. After processing, return energy for each contiguous azimuth bin of an illuminated area is dumped during a respective "look" of the antenna.

Abstract: A valve plug assembly for use in a steam throttle valve includes a valve body and a removable guide ring attached to one end of the valve body. An outer edge portion is removed from the guide ring at the interface with the valve body so that a circumferential groove is defined about the valve plug when the guide ring is assembled to the valve body. A slot is formed in one wall of the groove, preferably in the guide ring, and a wear ring inserted in the slot. The wear ring extends above the wall surface and terminates in an angled bearing surface. A pressure seal ring is formed with a mating bearing surface and is placed in the groove prior to assembly of the valve plug. The angular taper on the mating bearing surfaces causes some retraction of the pressure seal ring in response to sudden valve plug movement in the closed direction.

Abstract: An arrangement for determining an amount of SO.sub.2 present in the gaseous emissions of a combustible process utilizes an oxygen measuring device and the resultant O.sub.2 measurement to make an inferred determination of such SO.sub.2 measurement. A processing element reads an EMF signal representative of the O.sub.2 present and calculates therefrom, an amount of SO.sub.2 which can be selectively or automatically displayed alone or in conjunction with the O.sub.2 measurement.

Abstract: A modified inspection apparatus for inspecting nuclear fuel pellets for surface defects includes a pellet guide chute assembly extending through an ultrasonic inspection chamber. The guide chute assembly has a support substrate and a pair of elongated plates attached on respective upper adjacent sides of the substrate. The substrate is composed of a pair of elongated wall sections rigidly attached together to have a V-shaped configuration in cross section. The plates are adjustably attached on the substrate wall sections for supporting a nuclear fuel pellet between and on adjacent longitudinal portions of the plates located in the inspection chamber.

Abstract: A corrosion product monitoring system and method are described using a recirculation loop including a sample line, a particulate collection vessel, a recirculating pump, a microporous membrane "cross-flow" filter, and valves to control the flow rate and pressure of a fluid sample taken from the secondary fluid system of a nuclear power plant. The liquid sample is processed at a constant flow rate and temperature. When a relatively short time has elapsed in a trial sample run to stabilize conditions in the sample line, an actual sample run is started by feeding sample into the loop. Non-soluble, particulate concentration increases in the filter and particulate collection vessel as the run progresses. The permeate of soluble contaminants is passed through an ion exchange column to concentrate soluble ions in the sample. The filter is backwashed on a timed cycle by filtered water pressurized by a pump, or gas pressure, by realigning the system valves.

Abstract: In a method for nondestructive measurement of the heat affected zone of an identification code on a nuclear fuel rod tube, the change in impedance of an electromagnetic coil produced by a portion of the tube to be etched with a bar code is measured before and after the etching of the bar code is performed by use of laser power. The impedance change in the coil produced by the bar code-bearing tube portion is compared with the impedance change produced in the coil by the same tube portion before the bar code is generated thereon to determine whether a maximum allowed depth of the heat affected zone of the tube portion has been exceeded.

Abstract: A hydraulic lock for latching a displacer rod drive mechanism in an up position. A piston having a truncated cone-shaped valve element is formed at an end of the drive rod. A complementary truncated cone-shaped valve seat is formed in the cap of the reactor housing. When the drive rod is activated to the up position, the valve element seats against the valve seat creating a seal and a pressure boundary. The piston is provided with piston rings. The pressure differential acting across the piston is transferred to the area of contact between the valve element and valve seat thus maintaining the drive rod in the up position and preventing leakage flow from around the piston rings. A hydraulic control system for operating the hydraulic latch is also disclosed.

Abstract: A method of improving the quality of metal matrix fiber reinforced monotape and thin foil overlays made by the arc spray process by tailoring the surface finish of mandrels used in the process to the overlay being formed and making the mandrels of materials with high thermal conductivity so that the spray applied overlays hold and adhere to the mandrel during the spraying process and are easy to remove from the mandrel without damaging the overlay after the spray has solidified.