Abstract: The invention provides at least two electrochemical sensors positioned in a nuclear reactor or in a system adjacent to the nuclear reactor, wherein at least one of the at least two electrochemical sensors has a heated zirconium electrode, and the at least two electrochemical sensors produce voltages proportional to an electrochemical corrosion potential for a surface that each of the at least two electrochemical sensors are installed upon. The invention also provides an arrangement configured to accept the voltages produced by the at least two electrochemical sensors, wherein the arrangement is configured to determine an electrochemical corrosion potential of a zirconium fuel rod in the nuclear reactor based upon the voltages of the at least two electrochemical sensors.

Abstract: An in-core neutron monitor that employs vacuum microelectronic devices to configure an in-core instrument thimble assembly that monitors and wirelessly transmits a number of reactor parameters directly from the core of a nuclear reactor without the use of external cabling. The in-core instrument thimble assembly is substantially wholly contained within an instrument guide tube within a nuclear fuel assembly.

Abstract: A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a graphing component that displays the plot of the neutron distribution from the unknown source over a Poisson distribution and a plot of neutrons due to background or environmental sources. The system further includes a known neutron source placed in proximity to the unknown source to actively interrogate the unknown source in order to accentuate differences in neutron emission from the unknown source from Poisson distributions and/or environmental sources.

Abstract: Provided are an operation support device and an operation support method for a nuclear power plant which are capable of accurately grasping the condition of a nuclear power plant and capable of offering support for instantly performing a predetermined operation by an operator when an unusual situation occurs. The operation support device for a nuclear power plant is provided with an operation state check display unit (20) for displaying whether or not a system or equipment necessary for a safe operation of the entire nuclear power plant operates on the basis of a command signal to the system or equipment and a bypass and operation impossibility state display unit (21) for displaying whether the system or equipment is operable or not.

Abstract: Disclosed herein are apparatus and methods for detecting and quantifying contaminants in aqueous solutions. In one embodiment, an apparatus for the detection of contaminants within a liquid comprises a sensor and a controller. The sensor comprises a film and a transducer configured such that, during use, a first surface of the transducer is in fluid communication with a liquid, and the film is disposed between the first surface and the liquid. The film can be a polymeric material capable of hindering the transport of a non-desired species therethrough. The controller is in operational communication to the transducer, and is configured to determine the concentration of contaminants within the liquid.

Abstract: An apparatus for inspecting and testing a startup range neutron monitoring system for a nuclear reactor. The apparatus includes: a neutron-flux detector; a preamplifier that amplifies an electric signal output from the neutron-flux detector; a pulse measurement unit that counts times when electric signal output from the preamplifier exceeds a discrimination voltage; a discrimination-voltage setting unit that applies the discrimination voltage to the pulse measurement unit; a voltage-setting unit that applies a voltage to the neutron-flux detector; an arithmetic processing unit that calculates an output power of the reactor based upon an output signal of the pulse measurement unit; an output unit that outputs data representing the output power of the reactor, calculated by the arithmetic processing unit; and an inspecting/testing unit that sets the discrimination voltage and the voltage to be applied by the voltage-setting unit.

Abstract: A method of determining in-reactor susceptibility of a zirconium-based alloy to shadow corrosion according to a non-limiting embodiment of the present invention may include immersing a first electrode and a second electrode in an electrolytic solution. The first electrode may be formed of the zirconium-based alloy, while the second electrode may be formed of a metallic material suitable for use in a nuclear reactor and having a higher electrochemical corrosion potential than the zirconium-based alloy. The method may additionally include irradiating the immersed first and second electrodes with electromagnetic radiation. A galvanic current may then be measured between the first electrode and the second electrode to ascertain the relative in-reactor susceptibility of the zirconium-based alloy to shadow corrosion. The present invention allows a simplified and more rapid method of developing solutions that mitigate shadow corrosion, thereby potentially saving years of expensive in-reactor testing.

Abstract: Provided is an automated periodic surveillance testing method and apparatus in a digital reactor protection system, which unites a passive testing means such as a self-diagnosis or an on-line state comparison with an active testing means such as an automatic logic test and the like in the digital reactor protection system. Accordingly, a device self-diagnosis, an on-line state diagnosis, and an automatic logic test are used as the automated periodic surveillance testing method in the digital reactor protection system. Thus, the time consumed in a periodic surveillance test can be minimized, thereby saving reactor operating costs, and excessive manpower can be avoided, thereby decreasing potential human errors. Also, a channel detour time at which one of multiple channels is detoured can be minimized based on the automated periodic surveillance test in the digital reactor protection system, thereby enhancing stability.

Abstract: A method for operating a process plant, in which a number of alarm notifications for indicating non-compliant operating events of the process plant are generated at process level. Alarm notifications which can be generated during the operation of the process plant are defined. At least a number of the generatable alarm notifications are assigned, in each case at least a first value or a second value as a dependency value. A current process state of the process plant is determined and depending on the determined process state, those alarm notifications to which the first value was assigned as a dependency value are not indicated.

Abstract: An apparatus may include two or more electrical conductors, one or more signal devices, and an analyzer. The one or more signal devices may be adapted to apply one or more signals to the two or more electrical conductors and receive one or more signals from the two or more electrical conductors. The analyzer may be adapted to determine power level in the nuclear reactor using at least one of the applied signals and at least one of the received signals. A method of determining power level in a nuclear reactor may include: measuring impedance values of two or more electrical conductors disposed in the nuclear reactor and using the measured impedance values to determine the power level. A method of operating a nuclear reactor may include: measuring the impedance values and using the measured impedance values to determine parameters of the nuclear reactor.

Abstract: There are provided a first display that displays a system diagram of a safety system and makes it possible to select a symbol indicating a safety-system plant equipment included in the system diagram; a second display that displays an operating device for operating the safety-system plant equipment and makes it possible to operate the operating device; and a safety system display control device that outputs the system diagram to be displayed on the first display, outputs on the second display an operating device corresponding to a symbol that is included in the system diagram and is selected by means of the first display, and converts operation of the operating device performed on the second display into a signal that is outputted to the safety-system plant equipment.

Abstract: This document's object is to provide an axial power distribution control method in which only the control of an axial power distribution in a nuclear reactor with a simple operation with a clear operational target keeps the control of a xenon oscillation, thereby suppressing the xenon oscillation to an extremely small magnitude in advance at the same time.

Abstract: A method of analyzing structural vibration according to one aspect of the present invention includes reception of data from a plurality of sensors on a structure, filtration of the data to exclude data outside of a selected frequency band, association of sensor locations with locations on computer model, and generation of an animation which displays the structural vibration.

Abstract: A boiling water reactor core power level monitoring system includes a desired length of high dielectric, non-linear material insulated coaxial type cable in close proximity to the reactor core and a time domain reflectometry apparatus configured to measure a temporary characteristic impedance change associated with the coaxial type cable in response to at least one of neutron or gamma irradiation generated via the reactor core.

Abstract: A method of maintaining a rod of a hydraulic cylinder for a motion compensation system of an offshore platform includes non-destructive testing of a metallic cladding deposited onto the rod. An inspection crawler includes a visual inspection device, an eddy current inspection device and an ultrasonic inspection device. The method includes rotating the visual inspection device, the eddy current inspection device and the ultrasonic inspection device around a circumference of the rod while moving the inspection crawler along a longitudinal axis of the rod to simultaneously collect data related to the metallic cladding from the visual inspection device, the eddy current inspection device and the ultrasonic inspection device. The data is analyzed to detect any discontinuities, i.e., defects, in the metallic cladding.

Abstract: A method is provided for recovering operating margin in a nuclear reactor. The reactor includes a steam generator, a Reactor Coolant System (RCS) having a hot leg with a temperature, Thot, and a cold leg with a temperature, Tcold, a Reactor Trip System (RTS) having an Over Temperature Delta Temperature (OTDT) trip function and an Over Power Delta Temperature (OPDT) trip function, and a control system. The method improves the RTS by filtering only the hot leg temperature signal of the RCS. Thus, the needs for separate Tavg and Delta-T filters, and for filtering of temperature signals in both the hot leg and cold leg are eliminated. A reactor system is also disclosed.

Abstract: A method for determining a fresh fuel bundle design for a core of a nuclear reactor may include defining a plurality of inputs including user-defined target conditions for evaluating one or more reference fresh fuel bundle designs for each of N bundle groups, and generating a response surface based on making single rod-type changes in each (i,j) rod location of each bundle of a given reference bundle design being evaluated for each of the N bundle groups. A search algorithm may be iterated to evaluate a given combination of multiple rod-type changes made simultaneously across each of the N bundle groups using the generated response surface to determine an accepted fuel bundle design for each of the N bundle groups that satisfies the user-defined target conditions.

Abstract: A method of fuel bundle consideration in a reactor. The method includes creating or editing bundle groups including fuel bundles.

Abstract: An apparatus for inspecting and testing a startup range neutron monitoring system for a nuclear reactor. The apparatus includes: a neutron-flux detector; a preamplifier that amplifies an electric signal output from the neutron-flux detector; a pulse measurement unit that counts times when electric signal output from the preamplifier exceeds a discrimination voltage; a discrimination-voltage setting unit that applies the discrimination voltage to the pulse measurement unit; a voltage-setting unit that applies a voltage to the neutron-flux detector; an arithmetic processing unit that calculates an output power of the reactor based upon an output signal of the pulse measurement unit; an output unit that outputs data representing the output power of the reactor, calculated by the arithmetic processing unit; and an inspecting/testing unit that sets the discrimination voltage and the voltage to be applied by the voltage-setting unit.

Abstract: A method and system is provided for a nuclear reactor safety related application. The method includes executing two forms of a same application-specific logic, one of the two forms implemented as hardware logic, and the other of the two forms implemented as software instructions for execution by microprocessor-based controlling software. Each form of the application-specific logic is executed with a same set of inputs. The method compares a result produced from the execution of the hardware-implemented form to a result produced from the execution of the software-implemented form. When the compared results concur, the controlling software performs actions associated with the concurring results by executing microprocessor-based software. When the compared results fail to concur, the controlling software reports the failure of the compared results to concur to an operator by executing microprocessor-based software, and thereafter places the microprocessor-based software system into an inoperative (INOP) mode.

Abstract: A nuclear reactor plant protection system printed circuit card comprises a first logic device having a number of basic logic circuits, and a second logic device operatively connected with the first logic device for testing the number of basic logic circuits without taking the printed circuit card out of service. A nuclear reactor plant protection system printed circuit card comprises a first logic device producing a first output signal in response to a test signal, a second logic device producing a second output signal in response to the test signal, and a comparator for comparing the first output signal and the second output signal, wherein the test signal has a pulse duration that is less than a latching period associated with the printed circuit card. A method of testing and a nuclear reactor control system incorporating the nuclear reactor plant protection system printed circuit card is also provided.

Abstract: In a method of determining an operating margin to a given operating limit in a nuclear reactor, operational plant data from an on-line nuclear reactor plant is accessed, and reactor operation is simulated off-line using the operational plant data to generate predicted dependent variable data representative of the given operating limit. The predicted dependent variable data is normalized for evaluation with normalized historical dependent variable data from stored operating cycles of plants having a similar plant configuration to the on-line plant. A time-dependent average bias and a time-dependent uncertainty value for the predicted dependent variable data are determined using the normalized historical dependent variable data, and a risk-tolerance level for the on-line plant is obtained.

Abstract: A method of operating a nuclear power plant includes determining and licensing a maximum power level at which the power plant can be operated subsequent to the beginning of a fuel cycle, and with the power plant being operated at less than its maximum power rating at certain times such as at the beginning of a fuel cycle. The maximum power level is greater than the power level that would be calculated based upon an assumption that the heat flux peaking factor (FQ) and enthalpy rise peaking factor (F?H) remain at their maximum level throughout an entire fuel cycle. The maximum power rating takes advantage of factors such as known reductions in FQ and F?H at certain points in the fuel cycle, the marginal additional capacity of the Balance Of Plant, and the occasional optimization of process parameters such as ultimate heat sink temperature and atmospheric conditions.

Abstract: A method for operating a system having a plurality of modes and interlocks between the modes is provided. The method includes operating the system in a first mode and switching the system to a second mode without going to a standby mode.

Abstract: A multifunctional photoelectric switch comprises a display section for displaying a first display information and a second display information. The first display information includes a plurality of items concerning a threshold value and the second display information includes a plurality of items concerning functions of the photoelectric switch. A switch is provided for switching information to be displayed on the display section between each type of display information. A selection menu for the user to select either “Easy” or “Pro” is displayed in the progress of making a transition from a “light reception amount and/or threshold value display” mode of the basic display information to an “operation function setting” mode of the second display information. The user selects and sets either “Easy” or “Pro” on the selection screen. In the “Pro” mode, the set items concerning all functions are displayed; in the “Easy” mode, only the basic items are displayed.

Abstract: In a boiling water reactor controlling each control rod hydraulically by driving a solenoid valve, the control system comprises an operation control means 41 having a duplicated data processing unit for generating sequence patterns based on the timing of the driving sequence based on the control information provided manually, a transmission control means 42 for creating a command word corresponding to each control rod being controlled based on said sequence pattern, and mutually communicating each command word between duplicated data processing units and computing the AND logic of said data within a predetermined time difference, and when the computed result coincide, transmitting the selected command word serially; a transmission unit 32 for receiving said command word and performing protocol conversion thereto, and transmitting the same to a plurality of transmission branch units positioned downstream as the control command; and a solenoid valve drive circuit 31 for driving the control rod drive unit corres

Abstract: A radiation measurement device includes a radiation detector generating an analog signal containing pulse components, an A/D converter converting the analog signal into sampled data, an n-th power pulse discrimination unit calculating n-th power values of the sampled data to discriminate the pulse component, where n is two or more, and a pulse counter counting a number of the discriminated pulse components.

Abstract: A branch amplifier card for a nuclear reactor control rod drive control system is provided. The control system includes a control processor, a plurality of transponder cards arranged in clusters with each cluster under the control of a branch amplifier card. The branch amplifier card is configured to receive commands from the control processor, send the converted commands to transponder cards under the control of the branch amplifier card and to a downstream branch amplifier card, receive an acknowledge word from transponder cards under the control of the branch amplifier card, add AC voltage threshold level information about the transponder cards under the control of the branch amplifier card to the acknowledge word, permit transponder trouble information attached to the acknowledge word to remain in the acknowledge word, and resend the acknowledge word including the transponder trouble information to an upstream branch amplifier card.

Abstract: Disclosed is a digital reactor protction system capable of self-excluding a software common mode failure.

Abstract: The present invention is an analysis method for simulating accidental phenomena that may occur in a nuclear power plant system and applying them to actual safety analysis of a power plant. The present invention is an optimum evaluation system for safety analysis, which may exactly simulate thermal hydraulic phenomena in the nuclear power plant system with obtaining a suitable safety margin for various kinds of virtual accidents.

Abstract: A picture of a plan view of an area is displayed on a screen of a base unit of a measuring apparatus. The picture contains symbols for respective traps disposed in the displayed area. A bar code is assigned to each trap for identifying it. When the bar code on one trap is read out, a marking “X” is added to the symbol for that trap, so that an operator can readily know the location in the area of that trap on the display screen and, therefore, the current position of the operator in the area.

Abstract: A method and apparatus for the detection of radioactive material in an area is disclosed. The apparatus comprises a transmitter operatively arranged to transmit electromagnetic radiation, a receiver operatively arranged to measure an intensity of the electromagnetic radiation, and processing means operatively arranged to determine the presence of radioactive material based on the intensity measurement. Two receiver configurations are possible. In the first, the receiver measures the intensity of the electromagnetic radiation reflected by ion tracks in the air proximate to the area scanned for radioactive material. Alternatively, the receiver measures the intensity of the electromagnetic radiation transmitted by the air proximate to the area scanned for radioactive material.

Abstract: The method includes receiving parameters input by a user and calculating crack behavior estimations based on the received parameters by using a plurality of accessible crack behavior models. The crack behavior estimations calculated from each of the models are displayed to the user in order to illustrate how the different models compare in calculating a desired crack behavior profile. The displayed crack behavior estimations utilize a compilation of both historical crack growth rate data, as well as predicted crack growth rate data, and may be displayed as an estimated crack growth rate versus time, or as estimated crack growth over time. These parameters are displayed graphically for each crack behavior model in order to enable the user to make a comparison for each crack growth model.

Abstract: A method and system for thermal-dynamic modeling and performance evaluation of a nuclear Boiling Water Reactor (BWR) core design is presented. Based on a predetermined generic transient bias and uncertainty distribution in the change in critical power ratio (&Dgr;CPR/ICPR), shifted histograms of fuel rod critical power ratio (CPR) are generated. Ultimately, the operating limit minimum critical power ratio (OLMCPR) of the reactor is directly evaluated from a shifted histogram of fuel rod CPRs for a particular set of initial conditions which result in a probability calculation representing the number of fuel rods subject to a boiling transition (NRSBT) during the transient condition being equal to a predetermined value.

Abstract: A risk-informed method for safety analyses of nuclear power generating systems is provided. In an exemplary embodiment, the method includes ordering events by an initiating event frequency, defining an initiating event frequency threshold value, defining acceptance criteria having an adjusted amount of conservatism, where the amount of conservatism is a function of the initiating event frequency, and analyzing an event by a deterministic safety analysis methodology when the event has an event initiating frequency at or above the threshold value, or analyzing an event by a probabilistic risk assessment methodology when the event has an event initiating frequency below the threshold value.

Abstract: A transponder card for a nuclear reactor control rod drive control system is provided. The control system includes a control processor and a plurality of electrical devices operationally coupled to the control processor. The transponder card is configured to receive commands from the control processor, energize an appropriate electrical device when commanded, detect a failure in control circuitry of the transponder card, send a failure alarm, and remove power from an electrical device during a control circuitry failure event when there is no command to energize the electrical device.

Abstract: A water monitoring system for a nuclear reactor is provided. In an exemplary embodiment, the water monitoring system includes a fiber optic cable having a first end and a second end, with the first end configured to optically couple to the reactor cooling water distribution system, and at least one laser light source optically coupled to the second end of the fiber optic cable. The water monitoring system also includes a spectrophotometer optically coupled to the second end of the fiber optic cable.

Abstract: In a boiling water reactor controlling each control rod hydraulically by driving a solenoid valve, the control system comprises an operation control means 41 having a duplicated data processing unit for generating sequence patterns based on the timing of the driving sequence based on the control information provided manually, a transmission control means 42 for creating a command word corresponding to each control rod being controlled based on said sequence pattern, and mutually communicating each command word between duplicated data processing units and computing the AND logic of said data within a predetermined time difference, and when the computed result coincide, transmitting the selected command word serially; a transmission unit 32 for receiving said command word and performing protocol conversion thereto, and transmitting the same to a plurality of transmission branch units positioned downstream as the control command; and a solenoid valve drive circuit 31 for driving the control rod drive unit corres

Abstract: A method and a device are provided for monitoring a power rise during startup of a nuclear reactor (diversitary excursion monitoring). In order to be able to shut down the reactor during startup in the event of prompt critical states, a power band situated in a lower measuring range is prescribed for a signal of power range channels which detects the reactor power in the power range. Startup is continued only when the signal does not exceed an upper limit within a minimum time, after the last occasion of exceeding a lower limit of the power band.

Abstract: The measurement device comprises a real-time measurement-signal acquisition module (25) and means (23, 24) for connecting the cables for picking up the voltage from electrical windings for measuring the movement of the control rods to the acquisition module (25), in order to deliver, to the acquisition module (25), voltage signals corresponding to the voltage induced in the windings while the control rods are being dropped. The signal acquisition module (25) is thus permanently connected to the voltage-signal pickup cables (29) and the signals relating to the set of nuclear reactor control rods may be recorded simultaneously. Means (26, 27) for using the voltage signals delivered by the acquisition system (25) allow the drop times of the control rods to be determined.

Abstract: An auction service is provided that stimulates competition between energy suppliers (i.e., electric power or natural gas). A bidding moderator (Moderator) receives bids from the competing suppliers of the rate each is willing to charge to particular end users for estimated quantities of electric power or gas supply (separate auctions). Each supplier receives competing bids from the Moderator and has the opportunity to adjust its own bids down or up, depending on whether it wants to encourage or discourage additional energy delivery commitments in a particular geographic area or to a particular customer group. Each supplier's bids can also be changed to reflect each supplier's capacity utilization. Appropriate billing arrangements are also disclosed. The technology required to facilitate forward delivery transactions, in which a buyer and seller agree to the terms of a transaction today but schedule the delivery for a future time, would be helpful to end users, resellers and suppliers.

Abstract: In a boiling water reactor controlling each control rod hydraulically by driving a solenoid valve, the control system comprises an operation control means 41 having a duplicated data processing unit for generating sequence patterns based on the timing of the driving sequence based on the control information provided manually, a transmission control means 42 for creating a command word corresponding to each control rod being controlled based on said sequence pattern, and mutually communicating each command word between duplicated data processing units and computing the AND logic of said data within a predetermined time difference, and when the computed result coincide, transmitting the selected command word serially; a transmission unit 32 for receiving said command word and performing protocol conversion thereto, and transmitting the same to a plurality of transmission branch units positioned downstream as the control command; and a solenoid valve drive circuit 31 for driving the control rod drive unit corres

Abstract: The present invention provides an apparatus and method for measuring nonferrous electrical resistance measurement. The method includes providing a nonferrous material, inducing a magnetic field on the nonferrous material, measuring the remote magnetic field of the nonferrous material, and comparing the measured remote magnetic field to a standard.

Abstract: A system and method is provided for a continual updating of the optimization of multiple operational control-variables during the operation of a nuclear reactor over a plurality of fuel cycles. A networked computer system includes one or more hosts programmed to execute an optimization process to identify and make changes in quantitative values of operational control-variables that result in improved efficiency and operational flexibility. Optimization and updating of operational control-variables may proceed selectively under manual control for inputting specific optimization constraints and reactor state-point information or may proceed autonomously through a repetitive performing of the optimization process based upon a predetermined user-defined strategy stored on the network.

Abstract: A method of controlling a nuclear power plant includes determining a first maximum linear heat generation rate and a first minimum critical power ratio by a core monitoring system, and determining a second maximum linear heat generation rate and a second minimum critical power ratio by utilizing the first maximum linear heat generation rate and the first minimum critical power ratio determined by the core monitoring system and plant data. The second maximum linear heat generation rate and the second minimum critical power ratio are compared with predetermined thermal limit values and a control signal outputted from an automatic power regulator system to a re-circulation flow control system and to a control rod control system is held when at least one of the second maximum linear heat generation rate and the second minimum critical power ratio exceeds the predetermined thermal limit values.

Abstract: An inspection apparatus for inspecting welds in a nuclear reactor jet pump includes a probe subassembly rotatably and linearly movably coupled to a frame structure configured to attach to a top flange of the reactor pressure vessel. The probe subassembly includes a plurality of probe arms pivotably coupled to a housing, with each probe arm including a sensor. The probe arms are pivotably movable between a first position where the probe arms are parallel to a longitudinal axis of the probe subassembly, and a second position where the probe arms are at an angle to the longitudinal axis of the probe subassembly. An insertion subassembly couples to the jet pump suction inlet. The insertion subassembly is sized to receive the probe subassembly and guide the probe subassembly into the jet pump through the jet pump suction inlet.

Abstract: A method and apparatus for controlling components in a component control system in a nuclear power plant includes an image processing system and display processor (IPS-DP) for issuing an encrypted command for a selected component in a component command system (CCS) in the nuclear power plant; a soft controller for receiving the encrypted command and matching the command with the selected component in the CCS for issuing a control command to the selected component; and control channel gateway for receiving the encrypted command from the IPS-DP and soft controller, deciphering the encrypted command, and, if authenticated, issuing a control command for said selected component in the CCS. Security and isolation, while complying with applicable codes and regulations, are assured.

Abstract: A component actuation circuit for an engineered safety features actuation system (ESFAS) includes a plurality of coincidence logic contacts, and a plurality of parallel-connected ESFAS component relays. Each of the coincidence logic contacts closes in response to a command signal. The plurality of parallel-connected ESFAS component relays are connected in series between at least two of the plurality of coincidence logic contacts. Closure of at least two of the coincidence logic contacts energizes the parallel-connected ESFAS component relays, thereby energizing a plurality of ESFAS components.

Abstract: A control system, and a control method, of a nuclear power plant capable of easily executing automatic output regulation by an automatic power regulator system even when a lower-accuracy maximum linear heat generation rate and a lower-accuracy minimum critical power ratio are determined in a short cycle by using brief calculation. While a core monitoring system does not calculate a maximum linear heat generation rate and a minimum critical power ratio, they are determined by utilizing the maximum linear heat generation rate and the minimum critical power ratio calculated by the core monitoring system as well as plant data, and the lower-accuracy maximum linear heat generation rate and the lower-accuracy minimum critical power ratio so determined are compared with predetermined thermal limit values.

Abstract: A communication network for nuclear plant protection systems includes monitoring and control channels, including a first pair of channels having first and second channels, the first pair of channels communicating through fiber optic data paths with a second pair of channels having third and fourth channels; a plurality of engineered safety feature trains, including first and second trains, the first train communicating directly with the first pair of channels and the second train, the second train communicating directly with the second pair of channels and the first train; a first vital power bus powering the first channel; a second vital power bus powering the second channel, and redundantly powering the first train and first vital power bus; a third vital power bus powering the third channel; and a fourth vital power bus powering the fourth channel, and redundantly powering the second train together with the third vital power bus.