Abstract: The operation of a nuclear fueled, electric power generating unit is monitored by utilizing decision tree analysis of selected system parameters to generate a representation of the real time system status. Current system status is presented to the operator either in the form of conclusory indications, such as verbal statements, representative of system status, or in the form of a visual display of the entire decision tree including indications of the path through the tree representative of current conditions. In either case, indications of off-normal conditions are accompanied by directions as to appropriate action to be taken, either by the operator or the automatic control system, to steer the system toward more acceptable conditions. In addition, the status indications are prioritized to indicate the seriousness of the off-normal conditions and to direct the sequence of corrective action to be taken when multiple off-normal conditions exist.

Abstract: A termination frame assembly mounts signal conditioner circuit boards for a data acquisition system individually on a frame with an electromagnetic interference (EMI) barrier extending along the front edge and bending back over the circuit board and then out to form an integral trough through which the field wiring is routed to field terminals on terminal strips in the front face of the barrier. The circuit board is installed from the rear with a guide block, keyed to accept only a selected one of a family of boards, lifting the center of the leading edge to align edge connectors with connectors on the rear of the terminal strips.

Abstract: A filter system wherein a cylindrical shell having open ends and a gas-impervious wall with means for supporting a filter tube coaxially within the shell to form an annular chamber therebetween has means for securing the filter tube to the other open end, such that gases from the enclosure must pass through the filter tube into the annular chamber and then out of the cylindrical shell. A jet pulse means is provided to provide a jet pulse of fluid to the annular chamber to flex the filter tube inwardly to dislodge solids collected on the interior surface of the filter tube.

Abstract: A method for determining the amount of dissolved oxygen in the aqueous medium from a steam generator system that results from air leakage into the system above the water level in a condensor hotwell and that which results from air leakage below the water level in the condensor. Intentional injection of air above water level and intentional injection of air below water level are effected and resultant dissolved oxygen contents measured. The air leakage rate and dissolved oxygen contents at steady state operation are also measured. From these measurements, the amount of dissolved oxygen resulting from above and below water level are determined mathematically or graphically.

Abstract: A quick opening hatch for use on a transfer tube of a nuclear reactor plant that is adapted to replace the conventional hatch on the transfer tube. A locking ring is provided with a plurality of screw openings that is adapted for connection to the transfer tube, and a hatch cover fitably received within the locking ring for closing-off the transfer tube. To lock the cover to the ring, latches are movably connected with the cover for locking engagement with the locking ring, and a sprocket with a plurality of crank arms is movably connected with the cover and the latches for movement thereof into locking engagement with a latch housing on the locking ring for locking the cover to the ring and out of engagement with the latch housing for releasing the cover from the locking ring so as to permit removal of the hatch cover from the locking ring to provide access to the transfer tube.

Abstract: Method and apparatus for dismantling, shearing and compacting a fuel assembly frame skeleton. A frame is provided which can be placed into the transfer canal of a fuel-handling building for severing a bottom nozzle from the thimble tubes and grids of the frame skeleton, compacting the remainder of the skeleton, and then further severing the thimble tubes and grids into shorter longitudinal lengths, and placing the shortened compacted severed pieces into a container for off-site shipment or on-site storage.

Abstract: A slide and swing chassis assembly for electronic equipment which can be slid from an enclosure and swung to one side to permit complete access to equipment on the chassis, as well as equipment at the rear of the enclosure. The chassis assembly has a pair of chassis side frames which slide along slide members within the enclosure, one of the side frames having a pivotal slide plate attached to the rear portion which is pivotal from a closed position at the rear of the chassis to an extended position parallel with the side frame, such that the chassis may be slid from the enclosure along the slide members, and swung to one side while supported by the slide plate.

Abstract: Malfunction under water-solid conditions responsive either to increase in mass flow or increase in heat flow into the reactor coolant is suppressed. The power-actuable reactor-coolant relief valve is opened for increase in reactor-coolant mass influx if the rate of change of coolant pressure exceeds a setpoint during a predetermined interval, if, during this interval, the coolant temperature is less than a setpoint and if the level of the fluid in the pressurizer is above a predetermined setpoint (water-solid state). The interval is set to preclude opening of the relief valve for transients.

Abstract: Control for the operation of a mechanical handling and gauging system for nuclear fuel pellets. The pellets are inspected for diameters, lengths, surface flaws and weights in successive stations. The control includes, a computer for commanding the operation of the system and its electronics and for storing and processing the complex data derived at the required high rate. In measuring the diameter, the computer enables the measurement of a calibration pellet, stores that calibration data and computes and stores diameter-correction factors and their addresses along a pellet. To each diameter measurement a correction factor is applied at the appropriate address.The computer commands verification that all critical parts of the system and control are set for inspection and that each pellet is positioned for inspection. During each cycle of inspection, the measurement operation proceeds normally irrespective of whether or not a pellet is present in each station.

Abstract: Each parameter of the processes of the nuclear reactor and of the components of a power supply which convert the thermal energy generated by the reactor into electrical power is monitored by a set of four like sensors. One each of the unlike sensors which monitor the different parameters is contained in a reactor-trip logic channel. Each such unlike sensor is referred to here as a "local sensor". Each channel is interlocked with the other three channels and receives the signals sensed by the other three sensors, herein called "remote sensors". Each channel also includes means for processing the signals from the local and remote sensors. The apparatus also includes means for tripping the reactor to deenergize or trip the control rod drive and insert the control rods fully into the core so that the reactor stops supplying power. The apparatus normally operates on a "two out of four" configuration. This assumes that all sensors are in normal operating condition.

Abstract: The redundant signals from the sensor assemblies measuring the process parameters of a nuclear reactor power supply are transmitted each in its turn to a protection system which operates to actuate the protection apparatus for signals indicating off-process conditions. Each sensor assembly includes a number of like sensors measuring the same parameters. The protection system has a number of separate protection units, each unit receiving the process signals from the like sensors of each assembly in its turn. The sets of process signals derived from the sensor parameter assemblies are each in its turn transmitted from the protection system to the control system which impresses control signals on the reactor or its components to counteract the tendency for conditions to drift off-normal status requiring operation of the protection system. A parameter signal selector is interposed between the protection system and the control system.

Abstract: A protection and control system for a nuclear reactor which monitors a variable operating parameter indicative of the state of reactor operation and identifies an abnormal rate of change in reactor operating conditions. The operating parameter monitored at a given time after the abnormal change in operating conditions is identified and is employed as a base for a variable setpoint defining a design limit within which the reactor can continue to operate. At a preselected time following the identification of the abnormal rate of change of the reactor operating conditions, control of the reactor is automatically modified to establish a reactor working environment in which the reactor can continue to operate. Should the established setpoint be exceeded, the reactor will automatically be tripped.In one embodiment the negative rate of change of neutron flux of the nuclear core is monitored and compared to a preselected reference.

Abstract: An adjustable face milling cutter is carried on a turntable rotatable about a central axis that is coaxial with the cylindrical shell of the steam generator in which the tubesheet is located, to machine a circular path on the upper tubesheet surface. For complete circle-by-circle scanning of the tubesheet surface, the radius of the circular machined path is variable by virtue of mounting the milling cutter on the outer periphery of a circular mounting member turnable to different locked rotary positions about an off-center pivot axis on the turntable. The rotary support for the turntable is at its outer periphery, as provided by an encircling support ring which in turn is supported by a ball bearing assembly having an inner race secured to the turntable top and an outer race secured to the support ring top; teeth on the inner race being provided to accommodate a motor-operated drive gear.

Abstract: A servicing machine for a steam generator is accurately set up in the generator channel head with a pivoted arm mounted for rotation in a plane parallel to the tubesheet. The angular position of the arm, the longitudinal position of a carriage mounted on the arm and the vertical position of a platform on the carriage are remotely controlled to maneuver a probe used in mapping the precise location of the thousands of holes in the tubesheet. Various operations are then performed at each precise hole location by tools carried by the arm mounted carriage to prepare for installation of new tubing. The operation of a pair of remotely controlled pivoted arms, one on each side of the channel head divider plate, is coordinated to automatically position the ends of U-shaped tubes in corresponding holes in the tubesheet on opposite sides of the divider plate and to secure the same in place.

Abstract: An improved tungsten inert gas-shielded non-consumable composite welding electrode having a solid tungsten rod center (12) and a concentric outer sleeve (14) substantially lower in electrical resistivity than the tungsten rod, bonded adhesively and cohesively to the tungsten by flame spraying so that the surface irregularities of the mating surface areas of the tungsten and outer sleeve mechanically interlock. The improvement is provided by coating the outer sleeve onto the tungsten center and adhesively and cohesively bonding the interface of the surface area of contact to maintain a minimum resistance electric coupling at welding operating temperatures.

Abstract: Apparatus for tracking a welding electrode (22) within a weld groove (12). As the welding arc struck between the electrode (22) and the workpiece (16) is oscillated laterally (14) within the groove means (28 and 30) are provided for supplying an indication of both the voltage drop between the electrode and the side wall of the groove as the arc approaches the side wall, and the width of the excursion of the arc from the center of oscillation to the point where the voltage is measured. The center of oscillation is then adjusted as a function of the measured width and voltage.

Abstract: An eddy current probe for mapping holes within a tube sheet of a steam generator, having a first coil (12) positioned at the top of the probe (10) with its axis coincident with the axis of the probe. A first coil pair (14 and 16) is arranged along a common axis perpendicular to the axis of the probe below the first coil (12) and is situated a distance from and on either side of the axis of the probe. A second pair of eddy current coils (18 and 20) is positioned along a common axis perpendicular to the axis of the probe and the axis of the first coil pair with the respective coils of the second pair located on either side of and spaced from the probe axis. Each of the respective coils are arranged to be separately excited by an alternating current source with the respective coil pairs coupled in opposition in corresponding balanced bridge arrangements.

Abstract: An improved method and system for chemically digesting low level radioactive, solid waste material having a high through-put. The solid waste material is added to an annular vessel (10) substantially filled with concentrated sulfuric acid. Concentrated nitric acid or nitrogen dioxide is added to the sulfuric acid within the annular vessel while the sulfuric acid is reacting with the solid waste. The solid waste is mixed within the sulfuric acid so that the solid waste is substantilly fully immersed during the reaction. The off gas from the reaction and the products slurry residue is removed from the vessel during the reaction.

Abstract: The work is scanned by acoustic energy from a focused-arc transducer and from an acoustic-lens transducer. An echo-ranging subassembly energizes the focused-arc transducer and processes the echo trains relfected from the lines or pencils in the work along which the acoustic energy is focused. A holographic echo-processing subassembly is connected to energize the acoustic-lens transducer and to process the echoes reflected from the work where the energy from the acoustic lens impinges. The echo-ranging subassembly and the holographic echo-processing subassembly are enabled alternately and the acoustic energy from the focused-arc transducer and from the acoustic-lens transducer impinge on, and is reflected by, each of a succession of elemental areas of the work. The outputs of the echo-ranging subassembly and of the holographic echo-processing subassembly are supplied to an elastic store which may include one or more shift registers.

Abstract: A method is described for electrically converting an analog signal into a digital representation in a manner that maximizes noise rejection. The digital representation is formed from a preselected number of discrete points corresponding to sampled approximations of the analog signal. In establishing the magnitudes of the respective points, digital samples of the analog signal are taken at a predetermined number of discrete coordinates along the analog signal on either side of the respective discrete points. The predetermined number of coordinates are averaged and employed as corresponding approximations for the respective discrete points in the digital representative reproduction of the analog signal. The effects of harmonics of power line frequencies associated with processing electrical equipment are minimized by sampling the discrete coordinates for a particular point over an integral number of cycles of the power line frequency.