Patent Application
20250226125
Controllers and local I/O modules 120 include controllers 123 in a triple modular redundant (TMR)—three controller—or quad modular redundant (QMR)—four controller—configuration to execute application software logic for all modes and states of plant operation, including startup, power operation, shutdown, and off-normal operations. Each system controller 123 may execute the same application software logic independently and asynchronously. Two-out-of-three voting for TMR configurations, or two-out-of-four voting for QMR configurations, may determine the state of system input and output signals. Multiple controllers 123 ensure continued capability to perform applicable voting of inputs, with continued execution of the control software logic without operator intervention in the event of a loss of a redundant input or instrument channel.
I&C system 100 may be controlled by application software having a series of modules each having of a series of functions, methods, or programmable logic threads that determine the state of outputs and control variables based on the state of inputs. Programmable sequence function charts (SFCs), software task enabling/disabling, or conditional logic is used to control portions of the software logic, and to control data flow through it. The SFCs and software logic are structured to establish and ensure that control functions are executed in a predetermined sequence, similar to that performed by the reactor operator(s) for a manually controlled reactor. Within the SFCs, conditional logic enables or disables threads of software logic and controls the flow of software logic from one module of the software to another.
Local I/O modules 125 are used to process input and output signals from local equipment that may interface with controllers 123 via switches 122 across network 121, which may be an ethernet or other digitized network configured for communication with controllers 123. The local equipment may include sensors and actuators, hardwired switches 131, alarms 132, and indicators 133 included in the system HMI 130. Local I/O modules 125 are configured in a TMR or QMR configuration with either three or four I/O controllers configured to process the type of I/O signals handled by the module. Examples of types of I/O signals include discrete, analog, thermocouple, vibration, serial, and digital communications using industry-standard communication protocols.
Redundant input signals are provided to I&C System 100 for those signals used in control of the reactor. Each of the redundant input signals is processed by unique I/O module 125 to ensure that adequate inputs exist for voting of input signals in the event of failure of a single I/O module 125. The state of outputs on an I/O module is determined based on two-out-of-three or two-out-of-four voting of the output state determined by each I/O controller on the I/O module 125. For discrete outputs that are used for control of the reactor, the output from each I/O module 125 is configured in a series/parallel configuration with the outputs of other I/O modules providing control outputs for the same control parameter. This ensures that final control outputs from the system are based on two-out-of-three voting even in the presence of a single component failure (e.g., output relay failure). For analog outputs used for control of the reactor, the final system output is determined based on a median select of the redundant control outputs for the same control parameter. Communications with I/O modules using industry standard communication protocols are performed using a network ring topology which ensures reliability of the communications in the presence of a single failure of a component or data link within the communications ring.
Redundant I/O network switches 122 are used to relay multiplexed communication data from local and I/O module I/O controllers 125 to I&C system controllers 123. I/O network switches 122 support communications with I/O module controllers 125 over copper or fiber optic media, as needed for a given system application. For example, where the distance between remote I/O modules 115 and I&C system controllers 120 is great or electromagnetic interference is present, fiber optic cable is used.
I&C System Human Machine Interface 130 receives simple limited inputs from and provides high level reactor status indications to operators for confirmation of proper operation of the automated control system. From HMI 130, plant operators request plant startup, shutdown, power setpoint(s) at which the reactor will be controlled by the automated control system etc. via HMI server 135 interfacing with human input devices 134 such as keyboards or touchscreens. The control input requests are transmitted from HMI 130 to control network 127 for input to controllers 123 via switches 126. Application software logic in I&C system controller 123 evaluates operator control input requests from HMI 130 and implements them only if all prerequisites, permissions, and interlocks are met for their implementation. Hardwired controls 131 are provided to support manual shutdown of the reactor in the event of failure of I&C system 100. Hardwired shutdown controls 131 are designed to function irrespective of the state of I&C system controllers 123, I/O modules 125, and other components executing software. The I&C system control logic is designed to continue plant operation in a predetermined state based on setpoints stored on and software logic executed by the system controllers. Power distribution components 124 may receive local or plant power to power all off the input, output and processing devices in HMI 130 and local I/O modules 120.
Remote I/O modules and equipment 110 are provided where needed to interface with reactor sensors and actuators. The functioning of remote I/O modules 115 and switches 116 is the same as that of local I/O modules 125 and switches 122 described above, and may receive input from the same to reflect the same switch settings, input, and output. Switches 116 may communicate across network 117, which may be an ethernet or other digitized network. Variable speed/frequency power sources 111 are included with the remote I/O modules 115 to control movement of control elements to a commanded position at a commanded speed. Variable speed/frequency power source 111 is also provided to control the speed of the coolant pump or circulator and therefore mass flow of coolant through the reactor. Analog-to-digital converters 112 may receive and translate control element position information. Power distribution components 114 may receive local or plant power to power all off the input, output and processing devices in remote I/O modules 110. Ethernet network 113 may permit communication between remote I/O modules and equipment 110 and local I/O modules and equipment 120.
This background provides a useful baseline or starting point from which to better understand some example embodiments discussed below. Except for any clearly-identified third-party subject matter, likely separately submitted, this Background and any figures are by the Inventor(s), created for purposes of this application. Nothing in this application is necessarily known or represented as prior art.
Example embodiments include systems of monitoring and commanding industrial systems like nuclear power plants without need for human operator intervention to achieve a change in system status in the short or long term. Example embodiment systems may include controllers that can change the facility physical configuration, like pump and turbine actuators and speed controls, control rod drives, fuel feeds, etc. Example embodiment system may include sensors that can detect the facility physical configuration, including coolant and fuel temperatures, moderator flow rates, energy production rates, control element positions, etc. and report the same electronically. Example systems include a computer or other configured processor interfaced with the controllers and/or sensors and programmed to handle multiple pieces of data from/to the same for operations. For example, the processor may determine reactivity of a nuclear reactor from the sensors and/or issue operational commands to plant actuators to maintain operations or achieve a different reactivity. The controller could use a simple reactivity summation across provided contributing factors and/or a physics model simulating the plant to determine reactivity, for example, and issue commands of control rod positioning and/or moderator flow volumes in response. For a nuclear power plant instrumentation and control module, the processor may be connected between remote or local I&C I/O switches and sensors. Multiple independent processors may be used, for example one per switch, and example embodiment system may resolve operation commands issued by the processors through a majority-or at-least-half-rule of the controllers distinctly interfaced with the switches. While human operator input is not required in a continuous, day-to-day, or even month-to-month manner, example embodiment systems may include displays and input interfaces for operators to monitor facility operations and potentially input overriding commands or high-level operating goals such as target reactivities, power levels, cycle lengths, etc.
Example embodiments will become more apparent by describing, in detail, the attached drawings, wherein similar elements are represented by similar reference numerals. The drawings serve purposes of illustration only and thus do not limit example embodiments herein. Elements in these drawings may be to scale with one another and exactly depict shapes, positions, operations, and/or wording of example embodiments, or some or all elements may be out of scale or embellished to show alternative proportions and details.
Because this is a patent document, general broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only examples set forth herein.
Membership terms like “comprises,” “includes,” “has,” or “with” reflect the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof. Rather, exclusive modifiers like “only” or “singular” may preclude presence or addition of other subject matter in modified terms. The use of permissive terms like “may” or “can” reflect optionality such that modified terms are not necessarily present, but absence of permissive terms does not reflect compulsion. In listing items in example embodiments, conjunctions and inclusive terms like “and,” “with,” and “or” include all combinations of one or more of the listed items without exclusion of non-listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s). Modifiers “first,” “second,” “another,” etc. do not confine modified items to any order. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship among those elements.
When an element is related, such as by being “connected,” “coupled,”
“on,” “attached,” “fixed,” etc., to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.).
As used herein, singular forms like “a,” “an,” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. Indefinite articles like “a” and “an” introduce or refer to any modified term, both previously-introduced and not, while definite articles like “the” refer to the same previously-introduced term. Relative terms such as “almost” or “more” and terms of degree such as “approximately” or “substantially” reflect 10% variance in modified values or, where understood by the skilled artisan in the technological context, the full range of imprecision that still achieves functionality of modified terms. Precision and non-variance are expressed by contrary terms like “exactly.”
The structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from exact operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments.
The inventors have recognized that typical industrial plant operations require operator intervention on a continuous or at least daily basis to achieve desired operations. Without continuous human feedback, no facility-wide analysis or configuration changes are implemented, and the facilities may enter unproductive or dangerous conditions. Moreover, where individual components may have failsafe or shutdown routines for their independent operation, there is no facility-wide automated controller that can coordinate and keep operable all such components. This is more so true for nuclear power plants, where there may be no single plant processor or instrumentation to gather plant-wide data and/or provide automated operations to all components. To overcome these newly-recognized problems as well as others, the inventors have developed example embodiments and methods described below to address these and other problems recognized by the inventors with unique solutions enabled by example embodiments.
The present invention is instrumentation and control systems for industrial facilities and methods of operating such facilities. In contrast to the present invention, the few example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention.
Multivariable controllers 200 may be further configured with physics models for a more detailed determination of reactor responses, including reactor heat transfer coefficients, temperature dependent reactivity coefficients, control element reactivities (worth), fuel depletion (burnup), and the quantity of fission product poisons present in the reactor core. Heat transfer of the coolant may be modeled to account for the need to limit reactor power in response to changes or faults in the coolant system. For example, models using TRACG, SCDAp/RELAP, MELCOR, etc. may be provided with plant configuration to allow multivariable controllers 200 to determine plant response from any change in control element position and/or coolant flow rate. Additionally, multivariable controllers 200 may be coupled with point or spatial kinetics formulations to predict neutronic behavior of the reactor based on operational power history of the reactor to determine this response.
Multivariable controllers 200 may determine an expected change in reactor power in thermal and neutron flux terms, and coolant temperature, resulting from changes to control element position and/or moderator/coolant flow rates. Similarly, multivariable controllers 200 may calculate the opposite, control element position(s) and/or moderator/coolant flows that will achieve a reactivity, power level, and/or coolant/moderator temperature. These calculations are used to establish limits for plant control by I&C controllers 123, and in conjunction with inputs from plant sensors, to confirm proper response of the reactor following control element repositioning, valve reconfigurations, moderator pump speed changes, etc. This feedback essentially provides closed loop control of reactor power and temperature to support automated control of the reactor.
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Because multivariable controllers 200 may directly interface with plant controllers and receive sensor data from the same, controllers 200 may effectively replicate or replace human input through HMI 130, such that a plant can be operated without human constant monitoring or interface up to full automation. Reactor startup, operation at power, and reactor shutdown can all be automated with direct control interface of controllers 200, with human operators potentially only monitoring and/or inputting high-level goals. Further, this automation can be achieved despite failure of sensors, actuators, input/output modules and controllers in a shingle channel, with such failures being bypassed. This streamlined deterministic reactor control may minimize the potential for human error and assure high reliability and availability of nuclear reactor controls.
Some example embodiments and methods thus being described, it will be appreciated by one skilled in the art that examples may be varied through routine experimentation and without further inventive activity. For example, although commercial nuclear power plant control systems are used in some example methods, it is understood that other plants are useable with example embodiments and methods.
Variations are not to be regarded as departure from the spirit and scope of the example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
