Abstract: Thermal expansion compensating arrangement including a vessel and a first member anchored to the vessel so that it can thermally expand uniformly radially outwardly in a given direction from a longitudinal axis of the vessel. A second member is disposed in the vessel with a desired alignment in the given direction relative to the first member at a base temperature, the second member being made of the same material as the first member. An anchoring arm is provided for anchoring the second member to the vessel. The anchoring arm has one end which forms a rigid connection with the vessel and another end which forms a rigid connection with the second member. The anchoring arm is made of material having a coefficient of thermal expansion for causing the anchoring arm to expand away from its rigid connection with the vessel while the second member thermally expands away from the rigid connection with the anchoring arm.

Abstract: An emergency transfer tube closure for a nuclear reactor well comprising an elongated, vertically-extending, U-shaped guide laterally disposed on each side of the transfer tube, a closure plate vertically disposed between the guides having rollers thereon riding within the guides permitting movement of the closure plate downwardly into sealing engagement with the transfer tube under emergency conditions.

Abstract: A power contact with low off current for switching a-c loads in response to a logic signal includes a rectifier bridge circuit in a series with the load and the a-c power source, a MOSFET connected across the d-c terminals of the bridge, and a series RC filter circuit in parallel with the MOSFET. A metal oxide varistor connected across the d-c side of the bridge protects the MOSFET from transients in the a-c circuit. While this power contact is capable of switching sizable a-c currents, the leakage current with the MOSFET off is less than 1/10 of a milliamp so that it can also be used to switch loads which draw very low level currents. The MOSFET is electrically isolated from the logic signal by an opto-isolator which has a unique switchable output which permits the power contact to be readily adapted for use with normally energized or normally deenergized loads.

Abstract: A T-connection fiber-optical repeater employs redundant electrical-to-optical converters for generating optical signals to be distributed to terminal devices connected the repeater, and redundant optical-to-electrical converters for receiving optical signals from the terminal devices. Reliability is markedly increased by including one or two mixing stars in the fiber system between the converter and the repeaters. The number of converters and supporting circuitry that is needed can be reduced by coupling more than one fiber from the star or stars to each converter. The reliability of the repeater can be further enhanced by using redundant optical-to-electrical converters to receive optical signals from other repeaters and by using redundant electrical-to-optical converters to emit optical signals to other repeaters. Monitoring optical-to-electrical converters can be coupled to the stars in order to detect failure of electrical-to-optical converters connected to the stars.

Abstract: The inner barrel assembly of a pressurized water reactor includes an array of interleaved first and second matrices of respective first and second pluralities of rod guides of corresponding first and second different types, disposed in parallel axial relationship, the bottom ends of the guides being affixed to the top core plate of a lower barrel assembly. A flexible support structure connects the top ends of the rod guides to a lower calandria plate and particularly includes corresponding first and second pluralities of top support plates respectively connected to the rod guides of the first and second different types and having outer peripheries generally corresponding to the respective first and second types of rod guides and inner openings for permitting axial passage therethrough of corresponding, first and second different types of rod clusters.

Abstract: Each of the either normally closed or normally open switches, in an n out of m voted power interface circuit having parallel connected groups of serially connected switches, is shunted by a high impedance resistor to form a leakage path through each group of switches. A detector associated with each group of switches, and responsive to the change of impedance produced by actuation of a resistor shunted switch in the group, generates an output signal, preferably a one bit digital signal, indicative of the state of the switches in the group in response to a sequence of test signals which selectively actuate fewer switches than are required to actuate the load controlled by the power interface. Compensation for large variations in supply voltage is provided by incorporating each group of switches into a resistance measuring bridge circuit in which the digital output signal is generated by a comparator connected across the bridge. Preferably, the bridge circuits share common reference voltage generating legs.

Abstract: A method of operating a pressurized water nuclear reactor comprising determining the present core power and reactivity levels and predicting the change in such levels due to displacer rod movements. Groups or single clusters of displacer rods can be inserted or withdrawn based on the predicted core power and reactivity levels to change the core power level and power distribution thereby providing load follow capability, without changing control rod positions or coolant boron concentrations.

Abstract: A tube support for U-shaped tubes of a moisture separator reheater is disclosed. The tube supports in the proximity of U-bend of the U-shaped tubes being divided into an upper movable tube support member and a lower immovable tube support member, whereby the U-shaped tube members are permitted to expand without binding.

Abstract: A contact chatter detector includes a bipolar power supply and a switching system which permits the fixed contacts of a relay under test to be connected either to the positive or the negative terminal of the power supply, the movable contacts of the relay under test being grounded. Depending upon the switch position and whether or not chatter is present, the fixed contacts may be at ground potential, a positive potential, or a negative potential. Binary gates continuously monitor the fixed contacts, and are able to accommodate the three input states by receiving power from power supply translation circuits which effectively adjust the gates to be responsive to the negative potential and ground at one switch position and to ground and the positive potential at another switch position. Interruption alarms connected to the gates determine whether chatter exceeds a predetermined minimum, regardless of the rate at which the chatter pulses occur.

Abstract: A dynamoelectric machine has rockable pedestal journal members to support the rotor. The rockable journal members ride on spherical buttons to permit movement. A lower bearing shell supports the rockable members within an outer housing. A key is provided in channels between the lower bearing shell and the outer housing which may be easily removed. Shims may be placed on top of the key as desired to effect positioning of the rotor.

Abstract: Drift compensation for the output signal of a magneto-optic current measuring system is achieved through the use of two light emitting sources, each at different frequencies, to generate two alternating optical input signals to the current sensor to establish a signal reference in order to compensate for signal drift caused by variable attenuator characteristics of the optical elements in the system.

Abstract: A low noise, high gain differential amplifier suitable for EEG amplification is constructed in a shielded metal enclosure, preferably on a ground plane circuit board. The amplifier is battery powered to eliminate all possibility of noise from the power system. The amplifier utilizes a pair of operational amplifiers to provide high input impedance for each of two input signals. A differential amplifier generates an internal signal which is filtered and amplified by a pair of bandpass amplifiers and overlapping low pass and high pass amplifiers.

Abstract: A circuit arrangement for monitoring ground faults to a normally ungrounded coil of a motor, the circuit arrangement including;a source of a low-level d.c. voltage, the source having first and second output terminals between which the d.c. voltage is established and a conductive connection being established between the first output terminal and the motor coil;a current responsive unit connected between a point at ground potential relative to the motor coil and the second output terminal of the source for producing an output signal proportional to the amplitude of current flow between the second terminal and ground; anda motor control unit connected for preventing operation of the motor when the output signal from the current responsive means reaches a selected value.

Abstract: An improvement in a process for operating a gas turbine system containing a compression unit, a combustion unit and an expansion unit to operate a generator, wherein a low BTU gaseous fuel is used in the combustion unit and a portion of the air from the compression unit is bled from the system so as to prevent surges in the compression unit by limiting the flow of combustion gases to the compression unit, which comprises heating the air charged to the compression unit so as to reduce the volume of air from the compression unit that is bled from the system, and thereby increase the efficiency of the gas turbine system.

Abstract: A modular head assembly (110) for a nuclear reactor pressure vessel includes a closure head (112) having control rod drive mechanisms (116) mounted therein and projecting thereabove. Cooling baffles (118) provide air paths for cooling air for the CRDMs (116), and a lower air manifold (120) is fluidically connected to the cooling baffles (118) as well as to vertically upwardly extending air ducts and manifolds (136, 138, 140). Axial flow exhaust fans (126) are fluidically connected to the ducts (140) through means of plenum chambers (162) with the latter mounted upon a missile shield plate (134). The missile shield plate (134) is fixedly mounted upon closure head lift rods (144) as is a seismic support platform (128).

Abstract: A low noise EEG probe wiring system that substantially eliminates noise picked up by the loop enclosed by the cables of the wiring system, electrostatic and magnetic noise, and noise due to triboelectric effects. The low noise EEG probe wiring system comprises a pair of coaxial cables each including a central connector, a graphite coated insulating layer positioned around the central conductor, a first braid shield positioned around the graphite coated insulating layer and along the length of the coaxial cable, and a first insulator layer positioned around the first braid shield and along the length of the coaxial cables.

Abstract: A hatch assembly has an annular seat, a hatch cover and a plurality of latching units. Each latching unit has a slidably supported locking bolt movable generally radially inwardly with respect to the annular seat into a hatch cover locking position and generally radially outwardly into a hatch cover releasing position. In the hatch cover locking position at least one length portion of the locking bolt extends over the hatch cover for maintaining the hatch cover on the annular seat. Each latching unit further has a rotary crankshaft, an operating handle torque-transmittingly connected to the crankshaft for applying a locking torque and an opposite, releasing torque thereto; and a coupling mechanism for connecting the crankshaft with the locking bolt and for converting rotary motion of the crankshaft to linear motion of the locking bolt. The coupling mechanism has a spring for transmitting the locking torque from the crankshaft as a radially inwardly oriented resilient force to the locking bolt.

Abstract: The real time actual and reference values of parameters pertinent to the key safety concerns of a pressurized water reactor nuclear power plant are used to generate an integrated graphic display representative of the plant safety status. This display is in the form of a polygon with the distances of the vertices from a common origin determined by the actual value of the selected parameters normalized such that the polygon is regular whenever the actual value of each parameter equals its reference value despite changes in the reference value with operating conditions, and is an irregular polygon which visually indicates deviations from normal otherwise. The values of parameters represented in analog form are dynamically scaled between the reference value and high and low limits which are displayed as tic marks at fixed distances along spokes radiating from the common origin and passing through the vertices.

Abstract: A holddown spring retention assembly for use in a nuclear reactor having a pressure vessel, a core barrel having an upper outwardly extending flange, an inner barrel having an upper outwardly extending flange and an annular holddown spring, the barrels and the spring being installed in the pressure vessel during normal operation, with the inner barrel flange disposed above the core barrel flange and the holddown spring interposed between the core barrel flange and the inner barrel flange, the holddown spring retention assembly is composed of a plurality of assembly units disposed around the periphery of the holddown spring, each unit including a lift lug secured to the outer periphery of the spring and having at least one outwardly radially projecting portion and a hanger secured to the inner barrel flange and having a lower portion suspended below the inner barrel flange and below the radially projecting portion of the lift lug means; the lower portion being arranged to support the radially projecting portio

Abstract: A tool for maintaining ice baskets associated with a nuclear reactor system. The frame of the tool includes a platform which is disposed on a lattice support structure surrounding a selected and isolated basket. The tool includes an electric drill mounted for vertical reciprocation, in parallel axial relationship with the ice basket, and plural, selectively connectable auger shaft sections having a continuous helical fin thereabout which are connected in succession between the drill and a rotary drill bit, for drilling a hole of the required length, down through the ice within the ice basket. The drill then is maintained at an upper, vertically fixed position and a funnel positioned about the auger; ice chips or flakes are fed into the funnel while the drill is driven in reverse rotation, the auger conveying the ice to the bottom of the ice basket for filling lowermost voids and for filling successively higher voids as the auger is withdrawn.