JP7699565B2 - Plant function management support method and plant function management support device - Google Patents

Description

The present invention relates to a method and device for supporting plant function management of a nuclear power plant.

In recent years, the expansion of renewable energy has led to demands for nuclear power generation to be more competitive in terms of productivity. In addition, nuclear power generation is also expected to serve as a baseload power source that can provide a stable supply in a planned and continuous manner due to tight power supplies. For this reason, there is an increasing need for highly reliable equipment management technology to eliminate factors that lead to unplanned shutdowns of power generation facilities.

For example, Patent Document 1 discloses a power plant operation management support device that includes an operation parameter extraction unit that extracts the operation parameters of the power plant and an information transmission command unit that transmits information on the operation parameters of the power plant extracted by the operation parameter extraction unit, thereby enabling appropriate sharing of information related to the operation management of power plants, including nuclear plants.

JP 2020-169964 A

At nuclear power plants, the operator is required to take on an initiative called Configuration Management (CM), which maintains or manages the consistency of the three elements of design requirements, design configuration information, and physical configuration. Since the start of operation, the consistency of these three elements has been maintained at nuclear power plants by performing conservative maintenance to maintain the performance at the time of start-up.
Conventionally, maintenance of equipment at nuclear power plants has been carried out with a large margin of error in terms of required equipment performance and deterioration state, but in the future, more economical and stable maintenance and facility management will be required.

In order to maintain and manage equipment with greater reliability and cost-effectiveness, it is necessary to monitor the performance required of the equipment or device and take effective maintenance measures at the appropriate time to prevent performance degradation while maintaining the three elements.

The object of the present invention is to provide a plant function management support method and a plant function management support device that monitors parameters related to plant functions and maintains the consistency of the three elements by appropriately maintaining or managing plant functions and performance based on the parameter information.

In order to solve the above-mentioned problems, the plant function management support method of the present invention includes the steps of extracting monitoring parameters that monitor plant required functions and extracting design requirement thresholds of the monitoring parameters that determine maintenance or management of plant functions and performance, acquiring values of the monitoring parameters, predicting changes over time in the monitoring parameters based on the acquired monitoring parameter values, determining the time at which the predicted value of the monitoring parameters will reach the design requirement threshold, and setting the predicted value of the changes over time in the monitoring parameters at a time obtained by subtracting an action lead time from the aforementioned time as an action threshold, and comparing the acquired monitoring parameter values with the action threshold, so that when the acquired monitoring parameter value reaches the action threshold, plant maintenance or corrective measures are implemented .

In addition, the plant function management support device of the present invention includes a plant function management unit that extracts monitoring parameters that monitor plant required functions and extracts design requirement thresholds of the monitoring parameters for determining maintenance or management of plant functions or performance, a parameter monitoring unit that acquires the monitoring parameters, a parameter judgment unit that compares the acquired monitoring parameters with the design requirement thresholds, and an action threshold update unit that predicts changes over time in the monitoring parameters based on the acquired monitoring parameter values, determines the time at which the predicted value of the monitoring parameter will reach the design requirement thresholds, and sets the predicted value of the changes over time in the monitoring parameters at a time obtained by subtracting an action lead time from the aforementioned time as an action threshold, and the parameter judgment unit compares the acquired monitoring parameter values with the action thresholds, and implements maintenance or corrective measures for the plant when the acquired monitoring parameter value reaches the action threshold .

According to the present invention, it is possible to provide a plant function management method and a plant function management device for maintaining the consistency of three elements by appropriately maintaining or managing the plant functions and performance based on parameter information.
Additionally, parameter monitoring can be used to predict facility or equipment performance degradation in combination with lead time information for implementing maintenance or corrective measures, providing users with the appropriate timing for implementing maintenance actions.
Furthermore, by updating the prediction data based on the actual measured values of the monitoring parameters, it is possible to improve accuracy and assist in the continuous maintenance or management of the three elements.

1 is a diagram for explaining three elements of a CM design requirement, design configuration information, and physical configuration in a plant function management support method and a plant function management support device for a nuclear plant according to an embodiment. FIG. 1 is a diagram illustrating a configuration of a plant function management support device according to an embodiment. FIG. 11 is a flow diagram illustrating a three-element matching confirmation operation. FIG. 2 is a diagram illustrating a configuration of a plant function management support device according to an embodiment for formulating a maintenance plan. FIG. 11 is a flow diagram illustrating a process for determining an action threshold for a monitoring parameter. 11 is a diagram for explaining a method of determining an action threshold when the predicted curve of the aging change of a monitoring parameter is a straight line or a simple curve. FIG. FIG. 13 is a diagram illustrating a method for determining a predicted curve of the aging change of a monitoring parameter based on the upper peak value of the measured value of the monitoring parameter when the measured value of the monitoring parameter has a range, and for determining an action threshold. This is a diagram showing the monitoring items of functions or performance in the control function of the core reactivity and power output of the control rod drive mechanism (CRD) in TR-107434. FIG. 1 is a diagram showing a decrease in pump flow rate due to aging of the pump. FIG. 4 is a diagram showing an example of a pump performance curve showing the relationship between the flow rate and the discharge pressure of a pump. FIG. 13 is a diagram illustrating an example of an estimate of an action lead time. FIG. 13 is a diagram illustrating an example of setting an action threshold value in consideration of an operation schedule. FIG. 13 is a flow diagram for continuously maintaining or managing plant function requirements using action thresholds.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
First, three elements of design requirements, design configuration information, and physical configuration of a CM in a plant function management support method and a plant function management support apparatus for a nuclear plant according to an embodiment will be described with reference to FIG.

In the embodiment of the plant function management support method and plant function management support device for a nuclear plant, as shown in FIG. 1, the design requirements (design requirement thresholds) and required function information (plant required functions) in the design, construction, and manufacture of the plant are stored as CM design requirements in a design requirement database (hereinafter referred to as design requirement DB50).

The plant function management support method and plant function management support device link monitoring parameter information corresponding to the request data based on the design request DB50, and also quantify the corresponding monitoring parameter information and threshold information from the qualitative function information.

Then, the basis information for the design requirement thresholds, the relationship between the design requirement functions and the monitoring parameters, and the target component information are stored in a design information database (hereinafter referred to as design information DB60) as CM design configuration information.

In the plant function management support method and the plant function management support device, the relationship between the design requirement function and the monitoring parameters, the thresholds that are the operating limit values and their basis information, and the component information corresponding to the monitoring parameters are extracted from the design information DB 60. In addition, threshold information for quantifying the design requirement function is extracted from the design information DB 60.

Furthermore, the monitoring parameters (parameter records and latest values) are stored in a monitoring parameter database 33 (hereinafter, referred to as monitoring parameter DB 33) as the physical configuration of the CM.
In detail, the monitoring parameter DB 33 stores data of the acquired monitoring parameters, and also stores past data and test data of similar parameters.

In the embodiment of the plant function management support method and plant function management support device for a nuclear plant, the consistency of three elements, the design requirement DB 50, the design information DB 60, and the monitoring parameter DB 33, is maintained or managed during the maintenance of the nuclear plant.

In other words, the design requirements DB50 corresponds to the design requirements of the CM, the design information DB60 corresponds to the design configuration information of the CM, and the monitoring parameter DB33 corresponds to the physical configuration of the CM. Since the consistency of the three elements of the design requirements DB50, the design information DB60, and the monitoring parameter DB33 is maintained or managed, the plant function management support method and the plant function management support device for the nuclear plant of the embodiment are in line with the CM initiative.

FIG. 2 is a diagram showing the configuration of the plant function management support device of this embodiment.
The plant function management support device of this embodiment includes a plant function management unit 10 that manages compatibility information for plant required functions, a parameter determination unit 20 that determines whether monitored parameters are within the ranges of various threshold values set for the parameters, a parameter monitoring unit 30 that acquires parameter information and records information related to the monitored parameters, an input unit 70 that inputs operation information of the device, a communication unit 80 that exchanges data with other devices, and an output unit 90 that notifies the user of warnings and action information.

In more detail, the plant function management unit 10 is composed of a plant required function extraction unit 11, a plant required function related information extraction unit 12, a monitoring parameter extraction unit 13, a design required threshold extraction unit 14, and a requirement determination unit 15, which will be described in detail later.

The parameter determining unit 20 is made up of a threshold determining unit 21 and a parameter change influence determining unit 22, the details of which will be described later.
The parameter monitoring unit 30 includes a monitoring information input unit 31, an input information recording unit 32, and a monitoring parameter DB 33, the details of which will be described later.

In FIG. 2, the plant function management support device of this embodiment is shown as being connected to a design request DB 50 and a design information DB 60 shared with other management devices via a communication unit 80, but the plant function management support device may also be configured to include a design request DB 50 and a design information DB 60.

Specifically, the plant function management support device of this embodiment is configured with a computer (information processing device) equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage device such as a HDD (hard disk drive), and a display.

As shown in FIG. 2, the HDD forms a monitoring parameter DB 33 that stores the various information described above, and the CPU executes the program stored in the HDD to function as the plant function management unit 10, the parameter determination unit 20, and the parameter monitoring unit 30. The output unit 90 is a display.

Next, the operation of checking the consistency of the three elements by the plant function management support device of this embodiment will be explained using the flow diagram in Figure 3.

Using the flow in Figure 3, the design requirement thresholds for achieving the performance required of CM and the measured values of the monitoring parameters (monitoring parameter values) are organized (visualized) using the plant function management support device, and the consistency of the three elements is confirmed.

In Figure 3, information and values associated during the flow are stored as related information that can be referenced from one another. Also, in Figure 3, the thresholds that are determined by the thresholds of the element functions of the operating limit values and economic indicators in the design requirements and are compared with the monitoring parameters associated with the element functions are called "design requirement thresholds."

In step S31, the plant required function extraction unit 11 of the plant function management unit 10 extracts the plant required functions from the design requirements DB 50.

In step S32, the plant required function related information extraction unit 12 extracts the component functions and design basis information of the required function extracted in step S31 from the design information DB 60, and manages them as related information of the required function. Here, the component functions refer to the performance, status, degradation information, etc. of the equipment required to achieve the required function. From the design perspective, this also includes information that serves as a constraint imposed from the functional design to the equipment design.

In step S33, the monitoring parameter extraction unit 13 extracts existing monitoring parameters and design basis information related to the element function from the design information DB 60, and manages them as related information for the element function.

In step S34, the design requirement threshold extraction unit 14 extracts the minimum required performance values of the element functions required to achieve the plant requirement functions as thresholds from the design information DB 60, and associates them with the monitoring parameters. In addition, the design requirement threshold extraction unit 14 extracts information that is the basis for the thresholds of the element functions as related information from the design information DB 60.

By performing steps S31 to S34 above, the relationship between the plant required performance and the monitoring parameters and related information are organized in the design requirements DB 50 and design information DB 60 in Figure 1.

In step S35, the threshold value determining unit 21 of the parameter determining unit 20 confirms that the latest value of the monitoring parameter acquired by the parameter monitoring unit 30 does not exceed the threshold value of the monitoring parameter associated with the element function. Then, the requirement determining unit 15 confirms that the threshold value is not exceeded in all of the element functions associated with the plant requirement function.
In this manner, the consistency between the design request DB 50, the design information DB 60, and the monitoring parameter DB 33 in FIG. 1 can be confirmed.

Next, we will explain how the plant function management support device of this embodiment monitors the performance required of equipment or devices during plant operation and formulates a plant maintenance plan to maintain consistency among the three elements of CM (design requirement DB 50, design information DB 60, and monitoring parameter DB 33).

For example, to prevent unplanned plant shutdowns or even long-term shutdowns, predictions of changes in monitoring parameters and information on lead times for maintenance actions can be used to help continuously maintain consistency among the three elements. Note that action lead time refers to the time required for consideration, procurement, work, etc., required to implement an action to restore the functionality of facilities or equipment.

Figure 4 is a diagram showing the configuration of the plant function management support device of this embodiment when formulating a maintenance plan.

The plant function management support device of this embodiment is configured by adding an action threshold update unit 40 that formulates a maintenance plan to the plant function management support device described in FIG. 2. The other configuration of the plant function management support device of this embodiment is the same as that of FIG. 2, so the description will be omitted here.

The action threshold update unit 40 is composed of a prediction information extraction unit 41, a prediction execution unit 42, a maintenance or corrective action information extraction unit 43, an action lead time estimation unit 44, and an action threshold determination unit 45, which will be described in detail later.

With this configuration, the action threshold update unit 40 predicts the time when the threshold of the plant required function will be reached from the predicted value of the monitoring parameter, and extracts maintenance actions and their lead times. Then, from the above time information (predicted time) and lead time information (extracted lead time), it sets a new threshold (action threshold) for the monitoring parameter in the threshold determination unit 21. In other words, the action threshold update unit 40 combines the performance degradation prediction with lead time information for implementing maintenance or corrective measures, and sets a threshold (action threshold) that triggers the implementation of an action.

The plant function management support device of this embodiment uses this as a threshold for maintenance actions, and when it detects that a monitoring parameter has reached this threshold, it either notifies the user of a warning and action information, or initiates a maintenance process such as procurement.
This enables the plant function management support device to start maintenance-related actions (planning, procurement, actual work, etc.) and complete the actions before the facility or equipment loses the required function.

Next, referring to FIG. 5, the process of determining the action threshold for the monitoring parameters for implementing conservation or corrective actions in the action threshold update unit 40 will be described.

In step S51, the action threshold update unit 40 (see FIG. 4) selects the monitoring parameters for setting the action threshold.

In step S52, the prediction information extraction unit 41 (see FIG. 4) of the action threshold update unit 40 extracts the design request thresholds related to the monitoring parameters selected in step S51 from the design request DB 50 and the design information DB 60. In addition, prediction information such as simulation information that includes past data and test data from the monitoring parameter DB 33 and is necessary for predicting the aging of the monitoring parameters is acquired. The acquired prediction information is stored in the monitoring parameter DB 33.

In step S53, the prediction execution unit 42 (see FIG. 4) predicts the aging of the monitoring parameters by simulation or the like based on the prediction information acquired in step S52. In this case, the prediction method is selected from known techniques according to the type of parameters and data.

In parallel with steps S52 and S53, in step S54, the maintenance or corrective action information extraction unit 43 (see FIG. 4) extracts component information related to the monitoring parameter selected in step S51 from the design information DB 60. In addition, it extracts information on the maintenance or corrective action of the target component from a maintenance or corrective action database (not shown).

Maintenance or corrective action information is information necessary to inspect or repair the decline or deterioration of the functionality or performance of the target component. For example, it is work information, required materials, work resource information, work constraint information, etc.

In step S55, the action lead time estimation unit 44 estimates the action lead time for the maintenance or corrective action based on the information on the maintenance or corrective action extracted in step S52. For example, the action lead time for the maintenance is estimated based on information on material procurement, securing of work resources, actual work time, work constraint conditions, etc. Furthermore, if necessary, the action lead time is estimated to include the period for investigating the cause of parameter changes.

In step S56, the action threshold determination unit 45 determines an action threshold based on the predicted results of the aging of the monitoring parameters in step S53 and the estimated results of the action lead time in step S55.

In detail, the action threshold determination unit 45 uses the time at which the predicted value of the aging change of the monitoring parameter reaches the design requirement threshold set for the monitoring parameter as a reference, and sets the predicted value of the aging change of the monitoring parameter corresponding to the time minus the action lead time as the action threshold. At this time, the design requirement threshold can be reset according to the management purpose of the monitoring parameter.

In step S57, the action threshold determination unit 45 stores the action threshold determined in step S56 in the monitoring parameter DB 33.

Here, the method of determining the action threshold in step S56 will be described in more detail with reference to FIGS. 6A and 6B.
FIG. 6A shows a case where the predicted curve of the aging change obtained from the measured values of the monitored parameters is a straight line or a simple curve.

In FIG. 6A, as explained in step S56, first, the time when the predicted curve of the aging change of the monitoring parameter reaches the design requirement threshold of the monitoring parameter is calculated, and the time when the action is to be started is calculated by subtracting the action lead time from this time. Then, the predicted value of the monitoring parameter corresponding to the time when the action is to be started on the predicted curve of the aging change of the monitoring parameter is set as the action threshold.

In order to simplify the explanation in Figure 6A, a case has been described in which the predicted curve of the aging change of the monitored parameter simply decreases, but since there are no limitations on the characteristics of the monitored parameter and the parameters can change due to various factors, the measured value of the monitored parameter may have a range, as shown in Figure 6B. In this case, the design requirement threshold of the monitored parameter is managed by setting upper and lower limits, and the action threshold is also set accordingly.

Figure 6B shows a case where a predicted curve of the aging of a monitored parameter is calculated based on the upper peak value of the measured value of the monitored parameter, and an action threshold is calculated. In detail, the time at which the predicted curve of the aging of the monitored parameter reaches the upper design requirement threshold of the monitored parameter is calculated, and the time at which the action is to be started is calculated by subtracting the action lead time from this time. The predicted value of the monitored parameter corresponding to the time at which the action is to be started on the predicted curve of the aging of the monitored parameter is then set as the action threshold.

Instead of the upper peak value of the measured value of the monitored parameter, a predicted curve of the change over time of the monitored parameter may be calculated based on the lower peak value of the measured value of the monitored parameter, and an action threshold may be calculated.

A more specific example of setting the action threshold will be described below.
Figure 7 shows the monitoring items for the function or performance of the control rod drive mechanism (CRD) core reactivity and power control function described in "TR-107434 System Monitoring by System Engineers 37 System Monitoring Plans" issued by the Electric Power Research Institute (EPRI) of the United States. Below, we will explain an example of setting action thresholds for this.

In the control function of the control rod drive (CRD) core reactivity and power shown in Figure 7, the pump flow rate, CRD bearing temperature, pump rotor or gearbox or motor vibration frequency, and CRD pump discharge pressure are selected as monitoring parameters. The method for setting the action threshold for the pump flow rate is explained below.

Figure 8 shows a case where the pump's performance deteriorates due to aging during operation, causing the pump flow rate to decrease. The normal operating range of the pump flow rate is 40-42 GPM. The predicted curve of the change in pump flow rate (predicted curve of aging change), which is a monitoring parameter, can be obtained from predictions based on measured values, pump test results, past data, etc.

Figure 9 shows an example of a pump performance curve showing the relationship between pump flow rate and discharge pressure. The pump's operating limit value, design value, and measured value have a relationship that satisfies the consistency of the three elements, and a predicted curve of aging can be obtained by using the pump's discharge pressure as a monitoring parameter.

Next, the time required from start to finish (function recovery) of the maintenance or corrective action is estimated as the action lead time. Actions due to reduced pump flow rate include inspecting the pump, checking connections, verifying valve deterioration, and making repairs.

Here, as shown in Figure 10, the action lead time is estimated for pump inspection or repair work. In more detail, the time required to consider and plan each task of the action, the time required to procure materials, the actual work time, and constraints on carrying out the work (the time required until work permission is granted), etc. are extracted and organized. If there are items that can be carried out in parallel with other work, the shortest total time is used. The time required for consideration or planning, procurement of materials or services, actual work, and constraints that directly contribute to carrying out the work are generally constant for the implementation of the action. Constraints are conditions that are set when it is required to carry out an action at an effective timing, such as to improve the economic efficiency of the work.

Returning to Figure 8, based on the predicted curve of the aging of the monitored parameter (pump flow rate), an action threshold is set taking into account the action lead time and the timing at which the pump flow rate falls below the design requirement value. Then, when the measured pump flow rate reaches the action threshold, a maintenance or corrective action is implemented.

Here, we will use Figure 11 to explain a case where an action threshold is set taking into account the execution constraint of a maintenance or corrective action, that is, the operation schedule of the plant, in which actual work is performed during the plant's planned shutdown period.

Figure 11 shows, on a single graph, the time changes in the monitoring parameters of two managed objects that have the same design requirement threshold value. The time when the predicted curves of the aging changes of the two managed objects reach the design requirement threshold value is a timing during plant operation in the operation schedule. If a constraint condition for implementing the maintenance or corrective action is set to prevent the plant from being shut down due to the maintenance or corrective action of the target, the maintenance or corrective action work for the target is carried out during the shutdown period immediately preceding the plant operation period that includes the time when the predicted curves of the aging changes of the two managed objects reach the design requirement threshold value.

Then, the time is calculated by subtracting the action lead time from the start timing of the plant shutdown period, and the predicted value of the aging change of each monitoring parameter corresponding to this time is set as the action threshold value. In Fig. 11, the action lead time is set to 6 months, assuming that it takes 6 months to plan the maintenance or corrective action and to procure parts.
The above process is performed by the action threshold update unit 40.

In addition, in FIG. 11, different action thresholds are set because the change characteristics of the predicted curves of the aging changes in the target monitoring parameters are different.
As a result, the action threshold of the equipment being monitored can be appropriately set based on the action lead time and other constraints.

As mentioned above, the action threshold is determined by the design requirement threshold and monitoring interval of the monitoring parameters, and the timing of the lead of the maintenance action, so the value must be changed depending on changes in the design requirements, operational requirements, maintenance methods, etc.

For this reason, the plant function management support device of this embodiment repeats the flow shown in FIG. 12 to continuously maintain or manage the plant function requirements using the action threshold.

In step S121, the plant function management support device continuously acquires monitoring parameter data, new test data, etc., and continuously updates the action threshold.

In step S122, the plant function management support device uses the parameter determination unit 20 to determine whether the monitoring parameter has reached the action threshold, and if it has (Yes in S122), proceeds to step S123. If it has not (No in S122), the process ends.

In step S123, the plant function management support device outputs a warning to the user and action information such as resources, work content, and constraints required to implement maintenance or corrective measures, or starts a maintenance process.

In step S124, the plant function management support device records the content and results of the maintenance or corrective action taken in the maintenance or corrective action database.

In step S125, the plant function management support device confirms that there are no problems with the monitoring parameters.
The plant function management support device of this embodiment repeats steps S121 to S125 to continuously maintain or manage the plant function requirements using the action threshold value.

As explained above, the plant function management support device takes action to implement maintenance or corrective measures when a monitored parameter reaches an action threshold. However, if there is a sudden change in plant performance or equipment failure or signs of failure, there may be an abnormal change in the monitored parameter, such as a clear increase in the amount of parameter change over a certain period of time (a sudden change in the slope of the parameter change).

For this reason, the plant function management support device of this embodiment is provided with a parameter change impact determination unit 22 (see FIG. 2) that detects unusual changes in the monitoring parameters, and outputs an alarm when an unusual change in the monitoring parameters is detected.

In more detail, the parameter change impact determination unit 22 determines that an unusual change in the monitoring parameter has been detected when it determines that the action threshold reset by updating the action threshold is a value at a time earlier than the time corresponding to the action threshold before the update on the prediction curve of the aging change.

The parameter change effect determination unit 22 may also determine that an unusual change in the monitored parameter has been detected when the amount of change per unit time (the slope of the change) of the monitored parameter exceeds the allowable amount of change, and may set the allowable amount of change for the determination according to the monitoring purpose and necessity of the monitored parameter to be detected.

The present invention is not limited to the above-mentioned examples, and includes various modified examples. The above-mentioned examples have been described in detail to provide an easy-to-understand explanation of the present invention, and are not necessarily limited to those having all of the configurations described. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.

10 Plant function management unit 20 Parameter determination unit 30 Parameter monitoring unit 33 Monitoring parameter DB
50 Design requirements DB
60 Design information DB
70 Input section 80 Communication section 90 Output section

Claims (9)

Extracting monitoring parameters for monitoring required plant functions and extracting design requirement thresholds for the monitoring parameters for determining maintenance or management of the plant functions and performance;
obtaining values of the monitored parameters;
a step of predicting an aging change of the monitoring parameter based on the acquired monitoring parameter value, determining a time when the predicted value of the monitoring parameter will reach the design requirement threshold, and setting the predicted value of the aging change of the monitoring parameter at a time obtained by subtracting an action lead time from the determined time as an action threshold;
comparing the obtained monitored parameter value with said action threshold;
and implementing a plant maintenance or corrective action when the acquired monitoring parameter value reaches the action threshold . 2. The plant function management support method according to claim 1,
A plant function management support method, comprising the steps of: determining that an abnormal change in a monitored parameter has been detected when a change in the monitored parameter per unit time exceeds an allowable change amount. 2. The plant function management support method according to claim 1 ,
The plant function management support method, wherein the action lead time is information on material procurement, work resource acquisition, actual work time, or work constraint conditions for plant maintenance or corrective measures. 2. The plant function management support method according to claim 1 ,
A plant function management support method, comprising: predicting, when the acquired monitoring parameter value has a range, a change over time in the monitoring parameter based on a peak value on the upper or lower limit side. 2. The plant function management support method according to claim 1 ,
1. A plant function management support method comprising the steps of: predicting a change over time of a monitoring parameter based on an acquired monitoring parameter value; determining a time at which the predicted value of the monitoring parameter will reach said design requirement threshold; and, when said time is during a plant operation period, setting as an action threshold the predicted value of the change over time of the monitoring parameter at a time obtained by subtracting an action lead time from the start time of a shutdown period immediately preceding said operation period; and implementing maintenance or corrective measures for the plant during said shutdown period. 2. The plant function management support method according to claim 1 ,
A plant function management support method, comprising the steps of: determining that an abnormal change in a monitoring parameter has been detected when it is determined that an action threshold that has been reset by updating the action threshold is a value corresponding to a time earlier than a time corresponding to the action threshold before the update. A plant function management unit extracts monitoring parameters for monitoring required plant functions and extracts design required thresholds for the monitoring parameters for determining whether the plant functions and performances are maintained or managed;
A parameter monitoring unit that acquires the monitoring parameters;
a parameter determination unit that compares the acquired monitoring parameters with the design requirement thresholds;
an action threshold update unit that predicts an aging change of a monitoring parameter based on the acquired monitoring parameter value, determines a time when the predicted value of the monitoring parameter will reach the design requirement threshold, and sets the predicted value of the aging change of the monitoring parameter at a time obtained by subtracting an action lead time from the determined time as an action threshold;
the parameter determination unit compares the acquired monitoring parameter value with the action threshold, and when the acquired monitoring parameter value reaches the action threshold, implements a plant maintenance or corrective action.
A plant function management support device comprising: 8. The plant function management support device according to claim 7 ,
The action threshold update unit,
predicting the aging change of the monitoring parameter based on the acquired monitoring parameter value, determining the time when the predicted value of the monitoring parameter will reach the design requirement threshold, and when the time is during the plant operation period, setting the predicted value of the aging change of the monitoring parameter at a time obtained by subtracting an action lead time from the start time of a shutdown period immediately preceding the operation period as the action threshold;
A plant function management support device characterized in that during the shutdown period, maintenance or corrective measures are implemented for the plant. 8. The plant function management support device according to claim 7 ,
A plant function management support device comprising: a parameter change influence determination unit that determines that an unusual change in a monitored parameter has been detected when an amount of change per unit time in the monitored parameter exceeds an allowable amount of change, or that an unusual change in a monitored parameter has been detected when it is determined that an action threshold that has been reset by updating the action threshold is a value at a time earlier than a time corresponding to the action threshold before the update.

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