Abstract: An improved control circuit that is structured to energize another device such as a squib. A first portion of the circuit includes a first transistor and is structured to discharge at a first rate a first portion of a charge stored by a capacitor. Another portion of the circuit includes a second transistor and is structured to discharge a second portion of the charge subsequent to the discharge of the first portion of the charge and at a second rate greater than the first rate.

Abstract: A blocking device for preventing the actuation of an automatic depressurization system in a pressurized nuclear reactor system due to spurious signals resulting from a software failure. The blocking signal is removed when the coolant level within the core makeup tanks drop below a predetermined level.

Abstract: An improved control circuit that is structured to energize another device such as a squib. A first portion of the circuit includes a first transistor and is structured to discharge at a first rate a first portion of a charge stored by a capacitor. Another portion of the circuit includes a second transistor and is structured to discharge a second portion of the charge subsequent to the discharge of the first portion of the charge and at a second rate greater than the first rate.

Abstract: A blocking device for preventing the actuation of an automatic depressurization system in a pressurized nuclear reactor system due to spurious signals resulting from a software failure. The blocking signal is removed when the coolant level within the core makeup tanks drop below a predetermined level.

Abstract: A solid state reversing AC motor starter that employs a DC power source and a power bridge employing insulated gate bipolar transistors that provide an ungrounded three phase AC output. The AC output is connected to the power input of the motor starter, which requires simultaneous RUN and Directional Commands to initiate valve actuation.

Abstract: A current limiting DC motor starter employing a closed loop current measurement to provide precise current control that adapts to changing motor conditions, integrated with a solid state reversing motor starter. The motor starter further includes a calibrated overcurrent indication and a control system interface that reduces the likelihood that cable faults and other single failures will cause spurious actuation of the motor.

Abstract: A solid state reversing DC motor starter that is testable on-line and satisfies the requirements for nuclear safety grade equipment. The motor starter employs a bridge of solid state switches which connect the polarity of the motor winding to conform to the desired direction of travel. The reversing switch bridge is in series with the main switch that is coupled in parallel with a reduced current by-pass flow path.

Abstract: A solid state reversing DC motor starter that is testable on-line and satisfies the requirements for nuclear safety grade equipment. The motor starter employs a bridge of solid state switches which connect the polarity of the motor winding to conform to the desired direction of travel. The reversing switch bridge is in series with the main switch that is coupled in parallel with a reduced current by-pass flow path.

Abstract: A solid state reversing AC motor starter that employs a DC power source and a power bridge employing insulated gate bipolar transistors that provide an ungrounded three phase AC output. The AC output is connected to the power input of the motor starter, which requires simultaneous RUN and Directional Commands to initiate valve actuation.

Abstract: A current limiting DC motor starter employing a closed loop current measurement to provide precise current control that adapts to changing motor conditions, integrated with a solid state reversing motor starter. The motor starter further includes a calibrated overcurrent indication and a control system interface that reduces the likelihood that cable faults and other single failures will cause spurious actuation of the motor.

Abstract: A component interface module (CIM) arbitrates through priority logic component command signals from redundant systems and integrates the selected priority command signal with component feedback signals in component logic to generate a control signal for a component in a complex plant. The non-software based CIM is programmable for use with a variety of plant components. The component logic includes blocking logic that prevents or terminates generation of the control signal such as when component activation has been completed. Diagnostics incorporated into the CIM include: an input port interface test, a pulse test that continuously checks for proper propagation of test pulses through the priority and component logic, and a test of the functioning of the CIM output device such as a relay.

Abstract: A component interface module (CIM) arbitrates through priority logic component command signals from redundant systems and integrates the selected priority command signal with component feedback signals in component logic to generate a control signal for a component in a complex plant. The non-software based CIM is programmable for use with a variety of plant components. The component logic includes blocking logic that prevents or terminates generation of the control signal such as when component activation has been completed. Diagnostics incorporated into the CIM include: an input port interface test, a pulse test that continuously checks for proper propagation of test pulses through the priority and component logic, and a test of the functioning of the CIM output device such as a relay.

Abstract: An adaptable current regulating system provides a regulated current in accordance with both the actual characteristics of a system under control and the actual measured period of an AC supply. The system constantly monitors its status, and provides a master controller with the status of the system, and is programmed to provide control in accordance with information received from the master controller.

Abstract: A control system for a nuclear reactor is disclosed. A control rod strategy computer provides for dynamic control of core power distribution in both radial and axial directions and forms the basis for a partial trip capability. Several microprocessor-based computation centers are combined together in a data-sharing network which processors determine local power density, determine the instantaneous differential and integral reactivity worth of each group of control rods, determine and effectuate partial trip for immediate power reduction, determine and provide for uniform core burnup, and effectuate core reactivity changes by directing the movement of groups of four control rods from zero to one hundred percent of travel while minimizing power distribution factors throughout the core. The power control circuitry to move the groups of control rods are bus arranged such that the power circuitry is shared among the groups of control rods.

Abstract: In a protection system for a complex process control system which generates three independent actuation signals, the power circuit includes three pairs of switches arranged in three groups connected in series with each other and with a load device and a voltage source. Each group of switches includes two switches selected from different pairs of switches and connected in parallel. The same circuit topography is used for normally energized and normally deenergized loads with normally closed siwtches used with the former and normally open switches used with the latter. For testing the circuit, each group of switches is shunted by a resistor to form a leakage path through the configuration of switches. The impedance of each resistor is several times that of a closed switch such that the leakage current is insufficient to energize the load, but sufficient to be detected by a current detector which measures the current drawn from the voltage source.

Abstract: The dynamic logic of each channel of a multichannel protection system for a nuclear power plant provides a trip logic path and a global bypass logic path by which pulse signals from a clock source may be transmitted to a dc-to-dc power converter which energizes the undervoltage coils for a pair of contactors in the reactor trip switchgear. Each of the logic paths is constructed of basic logic units which in turn, each include a toroidal core of rectangular hysteresis loop magnetic material having a control winding which must be energized by a dc current in order for pulses applied to an input winding to appear at an output winding. Blockage of pulses through any one of the serially connected basic logic units in a logic path terminates the flow of pulses to the converter through that logic path. The control windings of corresponding logic units of the trip logic path in each channel are energized by one of a set of redundant sensors which monitor one of a plurality of reactor trip parameters.

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: Excessive swing of the feedwater in power supply apparatus on the occurrence of a transient is suppressed by injecting an anticipatory compensating signal into the control for the feedwater. Typical overshoot occurs on removal of a large part of the load, the steam flow is reduced so that the conventional control system reduces the flow of feedwater. At the same time there is a reduction of feedwater level in the steam generator because of the collapse of the bubbles under increased steam pressure. By the time the control responds to the drop in level, the apparatus has begun to stabilize so that there is overshoot. The anticipatory signal is derived from the boiling power which is a function of the nuclear power developed, the enthalpy of saturated water and the enthalpy of the feedwater injected into the steam generator. From the boiling power and the increment in steam pressure resulting from the transient are anticipatory increment of feedwater flow is derived.