Maintenance planning support method and maintenance planning support device

Abstract

To provide a maintenance plan support method capable of appropriately setting a maintenance execution period for a maintenance plan of a nuclear power plant.SOLUTION: A maintenance plan support method for a maintenance plan support device that supports creation of a maintenance plan for a nuclear power plant, comprises: a component determination step (step S102) of determining components for which deterioration prediction is to be performed for an apparatus for which extension of a maintenance cycle is to be considered when planning maintenance; a period proposal step (step S103) of determining deterioration trend data and maintenance execution deterioration amounts for the determined components, and proposing a maintenance cycle based on the deterioration trend data and the maintenance execution deterioration amounts; and a comparison step (step S104, step S802) of comparing the proposed maintenance cycle with a maintenance cycle organized in PMBD (Preventive Maintenance Basis Database) of EPRI (Electric Power Research Institute).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a maintenance plan support method and a maintenance plan support device that support plans for extending the maintenance cycles and for regular inspections of equipment in a nuclear power plant. [Background technology]

[0002] After the Great East Japan Earthquake, nuclear power plants in Japan were required to install additional equipment due to new standards established by the new standards, which increased the amount of equipment to be operated and maintained compared to the previous plan. As a result, the cost of constructing the equipment increased compared to the previous plan, so operators who manage and operate nuclear power plants need to reduce the maintenance costs of this equipment and increase the capacity factor in order to supply electricity at low cost.

[0003] One way to improve the economic efficiency of nuclear power plants is to reduce the cost of maintenance tasks. Reducing maintenance tasks makes it possible to reduce human resources and shorten the inspection period that requires plant shutdowns. Various proposals have been made to reduce maintenance tasks, focusing on time-based maintenance, which is commonly practiced in Japan. Time-based maintenance is a method in which specific maintenance tasks are performed when a specified time is reached, based on the operating hours or time elapsed since installation of the equipment to be maintained.

[0004] Patent Document 1 proposes a plant construction planning support device that supports the creation of plans for construction or renewal work on a plant consisting of multiple components to be constructed in a construction area, and that includes a database means that stores multiple pieces of performance data on work that has been carried out in the past (hereinafter referred to as past work), an input means for inputting the type and construction area of ​​the work object that is the same as or similar to the planned work (hereinafter referred to as planned work), a performance data extraction means that extracts from the database means performance data on past work that corresponds to the type and construction area of ​​the work object input by the input means, and a planning means that uses the performance data extracted by the performance data extraction means to create a process schedule that sets the work content and chronological order of the planned work.

[0005] Patent Document 2 proposes that a plant maintenance work management device has a database that stores data including information on the target equipment required for creating a maintenance work schedule, information on the maintenance work content, and information on workers and work equipment; a schedule management support module that presents the minimum information required for creating a schedule and allows the user to set the data, obtains information from the database based on the user-set data to create an optimal schedule while avoiding interference between tasks, and outputs messages as necessary; an input / output device that includes at least one of a workstation input device, a screen, and a handheld terminal; and an information processing device that executes the commands of the schedule management support module based on user commands input via the input / output device and outputs the processing results to the input / output device.

[0006] Patent Document 3 proposes a parts lifespan management system having a plurality of sites that detect the lifespan characteristics of parts of operating equipment, and a parts lifespan management server that is connected to this group of sites via a network and collectively manages the lifespan characteristics of each part at the group of sites, where the parts lifespan management server is equipped with: receiving means for receiving lifespan characteristic data of parts at each site sent from the group of sites via the network; remaining lifespan prediction means for predicting the remaining lifespan of parts using this lifespan characteristic data; storage means for organizing the remaining lifespan of parts for each site and for each part and storing a remaining lifespan database; and processing means for outputting the remaining lifespan status of parts or information on replacement parts based on this remaining lifespan database. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-170496 [Patent Document 2] Japanese Patent Application Publication No. 08-129414 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-157330 Summary of the Invention [Problem to be solved by the invention]

[0008] It is necessary to provide more reliable and efficient maintenance at nuclear power plants based on risk information and equipment deterioration. One way to achieve this is to carry out maintenance activities at the most effective timing in terms of both safety and economy. By understanding the deterioration of equipment and performing maintenance according to the deterioration status, costs can be minimized while maintaining safety. However, to do this, it is necessary to appropriately determine the timing of maintenance and create a long-term plan.

[0009] The present invention is an invention for solving the above-mentioned problems, and an object of the present invention is to provide a maintenance plan support method and a maintenance plan support device that can appropriately set the timing of maintenance implementation in a maintenance plan for a nuclear power plant. [Means for solving the problem]

[0010] In order to achieve the above object, a maintenance plan support method of the present invention is a maintenance plan support method for a maintenance plan support device that supports creation of a maintenance plan for a nuclear plant, comprising: The processing unit of the maintenance plan support device When making a maintenance plan, for equipment for which the extension of the maintenance cycle is being considered, Extracting parts of the equipment from the database, and extracting parts that affect the maintenance cycle of the equipment and deterioration-related information from the extracted parts; Parts for which deterioration prediction is performed extraction a part determination step (for example, step S102) to determine a part to be used; extraction and a cycle proposing step (e.g., step S103) of determining deterioration trend data and a maintenance implementation deterioration amount for the selected part, and proposing a maintenance cycle based on the deterioration trend data and the maintenance implementation deterioration amount. Other aspects of the present invention will be described in the embodiments described later. [Effects of the Invention]

[0011] According to the present invention, the timing of maintenance can be appropriately set for a maintenance plan for a nuclear power plant. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating a configuration of a maintenance plan support device according to an embodiment of the present invention. [Figure 2] 10 is a flowchart showing a maintenance plan support process according to the present embodiment. [Figure 3] 10 is a flowchart showing a part / site selection process for predicting deterioration of equipment for which an extension of the maintenance cycle is being considered. [Figure 4] FIG. 10 is a diagram showing an example of extracting and displaying information such as parts that affect the maintenance cycle of equipment, their deterioration mechanisms, and the lifespan until loss of function. [Figure 5] 10 is a flowchart showing a process for examining an extension of a maintenance cycle; [Figure 6] 10 is a flowchart showing a process for setting a recommended value of deterioration amount for performing maintenance of a device based on the importance of the device; [Figure 7] FIG. 10 is a diagram illustrating a setting image of a recommended value of deterioration amount for performing maintenance of a device. [Figure 8] 10 is a flowchart showing a gap analysis process of the importance of maintenance by comparing the PMBD and the maintenance period. [Figure 9] 10 is a flowchart showing a cost optimization process for the next regular inspection. [Figure 10] 10A and 10B are graphs showing examples of time-dependent changes in physical quantities correlated with device performance, where the graph with the symbol 10A is for the breaking elongation and the graph with the symbol 10B is for the amount of functional groups. [Figure 11] 1 is a diagram showing a configuration of a work process optimization support device according to an embodiment of the present invention; [Figure 12] 10 is a flowchart showing a process of supporting the creation of a work plan by the work process optimization support device. [Figure 13] FIG. 10 is a diagram showing an example of a display of the evaluation results of plan feasibility. [Figure 14] FIG. 10 is a diagram showing an example of a display of an evaluation result of a work proficiency level. [Figure 15] FIG. 10 is a diagram illustrating an example of change in work efficiency depending on the number of workers. [Figure 16] 10 is a flowchart showing a process for determining a work efficiency coefficient based on the number of workers. [Figure 17]10 is a flowchart showing a process for evaluating a work proficiency level for each work group. DETAILED DESCRIPTION OF THE INVENTION

[0013] In this embodiment, a method for supporting the extension plan of the maintenance cycle and the periodic inspection plan of equipment in a nuclear power plant is proposed. First, the terms used in this embodiment, features, etc. will be explained.

[0014] <Definitions of terms, etc.> Deterioration refers to a general decline in the functionality and performance required of equipment. For example, if a pump with a maximum flow rate of 100 L / m is required to have a flow rate of 50 L / m, when the pump's performance falls below 100 L / m it is considered a "deterioration of functionality," and when it falls below 50 L / m it is considered a "loss of functionality." Both are caused by deterioration.

[0015] The amount of degradation is the measured or estimated value of a physical quantity when changes in the material, mechanical, or electrical physical quantities of the parts and components (hereafter collectively referred to as "parts") that make up a device are associated with a decline in the device's function or performance. Parts are considered to have multiple physical quantities that are associated with degradation. In this embodiment, degradation due to changes in representative physical quantities is predicted by clarifying changes in device performance due to changes over time in a specific environment, and changes over time and in the amount of degradation in a specific environment. The amount of degradation used here is called the representative amount of degradation.

[0016] Deterioration trend data is data that shows the change in the representative amount of deterioration over time. This deterioration trend data is created based on the environmental conditions of each component and part of the equipment. The time from the present until the representative amount of deterioration reaches a level at which it is determined that functionality has been lost or that maintenance tasks are necessary is called the remaining life of the equipment.

[0017] Representative deterioration amounts and deterioration trend data are created based on actual equipment measurement data, environmental test data, etc. The accuracy of deterioration prediction changes depending on the representative deterioration amount used to create the deterioration trend data. More accurate deterioration trend data can be created by using measured values ​​or experimental values ​​with high measurement accuracy or by using deterioration amounts that have a high correlation with part deterioration. For this reason, it is desirable for the representative deterioration amount to have high measurement accuracy, a simple measurement method, and easy data collection.

[0018] (Features) In this embodiment, from the viewpoint of risk in the event that the equipment loses its function, a deterioration threshold is set as a maintenance cycle for maintaining a state in which functional requirements are satisfied. Risks can be broadly divided into safety-related risks and economic risks. In the case of nuclear power plants, the importance of equipment is usually classified taking these risks into consideration.

[0019] The maintenance planning support device sets the appropriate timing for performing maintenance tasks based on the classification of equipment importance, the characteristics of the deterioration trend data, the cost evaluation of the maintenance tasks, etc., and the amount of deterioration for performing maintenance based on the deterioration trend data. Regarding the characteristics of the deterioration trend data, the change curve of the amount of deterioration, resolution, minimum detectable amount of deterioration, etc. are taken into consideration, and a tolerance for the limit value of equipment function and performance is set.

[0020] In the cost evaluation of maintenance tasks, the costs involved in carrying out maintenance on the target part are compared. For example, if there are multiple maintenance tasks to choose from for a certain part, the maintenance planning support device will select the method that results in the lowest cost by comparing the costs of time-based maintenance and corrective maintenance, and will set the degradation amount threshold from the degradation trend data, taking into account the limit value of the amount of degradation to which that method can be applied.

[0021] The maintenance planning support device takes into account the characteristics of the deterioration trend data and maintenance costs, and appropriately sets the timing for performing maintenance tasks as a deterioration amount threshold. By performing these tasks, safety can be ensured and maintenance costs can be reduced.

[0022] <Maintenance planning support device> FIG. 1 illustrates a configuration of a maintenance plan support device 100 according to this embodiment. The maintenance plan support device 100 includes a processing unit 110, a storage unit 120, an input unit 130, an output unit 140, and a communication unit 150. The processing unit 110 includes a maintenance cycle extension unit 111 that considers extending a maintenance cycle, and a maintenance importance gap analysis unit 112 that compares the maintenance cycle with the Electric Power Research Institute's (EPRI) PMBD (Preventive Maintenance Basis Database). The maintenance cycle extension unit 111 includes a component determination processing unit 111A that determines components for which deterioration prediction is performed for equipment whose maintenance cycle extension is being considered when creating a maintenance plan, and a cycle proposal processing unit 111B that determines deterioration trend data and a maintenance implementation deterioration amount for the determined components and proposes a maintenance cycle based on the deterioration trend data and the maintenance implementation deterioration amount. The storage unit 120 stores equipment deterioration analysis data 121, a maintenance task list 122, equipment maintenance implementation deterioration amount setting information 123, and processing unit output information 124.

[0023] EPRI is the Electric Power Research Institute in the U.S. The PMBD (Preventive Maintenance Basis Database) is a database that aggregates PM (Preventive Maintenance) templates created for specific equipment under EPRI.

[0024] In FIG. 1, the processing unit 110 is a central processing unit (CPU) that executes various programs stored in RAM, a HDD, or the like. The storage unit 120 is a HDD that stores various data used by the maintenance plan support device 100 to execute processing. The input unit 130 is a device for inputting instructions to a computer, such as a keyboard or a mouse, and inputs instructions such as program startup. The output unit 140 is a display or the like that displays the execution status and execution results of processing by the maintenance plan support device 100. The communication unit 150 exchanges various data and commands with other devices via the network NW.

[0025] The maintenance planning support device 100 also includes a database device 200 in an external storage device. The database device 200 includes a degradation-related DB 210, an equipment importance-related DB 220, a regulation-related DB 230, a maintenance task-related DB 240, an EPRI PMBD-related DB 250, etc. DB refers to a database.

[0026] The data stored in each DB is explained below. The deterioration-related data stored in the deterioration-related DB 210 is data related to the deterioration of equipment, such as data showing the deterioration characteristics of equipment and parts (effects of deterioration, deterioration events and usage environment, methods for detecting deterioration, methods for correcting deterioration), maintenance and failure records (as-found data), deterioration test data, and PMBD (Preventive Maintenance Basis Database).

[0027] The equipment importance related data stored in the equipment importance related DB 220 is data related to the importance of equipment, such as the maintenance importance classification of equipment in a nuclear power plant, the importance of safety and economy, and required functional data of the equipment.

[0028] The regulation-related data stored in the regulation-related DB 230 is data related to domestic regulatory requirements.

[0029] The maintenance task related data stored in the maintenance task related DB 240 includes the equipment to be maintained, the basis for the equipment's maintenance cycle, maintenance tasks, incidental work related to the maintenance tasks, the resources required to perform these tasks, cost information, and the like.

[0030] The data stored in the EPRI PMBD-related DB 250 is data extracted to compare maintenance-related information (Criticality, Duty Cycle, Service Conditions, Task (maintenance method), Baseline (maintenance cycle), Failure Mode, etc.) with domestic equipment subject to maintenance.

[0031] <Overall processing flow> 2 is a flowchart showing the maintenance plan support process S100 according to this embodiment. The maintenance plan support process S100 includes a periodic inspection plan optimization support process (details of which will be described later with reference to FIG. 12).

[0032] In step S101, the processing unit 110 constructs a database stored in the maintenance plan support device 100 shown in FIG. 1 and the work process optimization support device WPO shown in FIG.

[0033] In step S102, the processing unit 110 selects parts and portions of the equipment for which deterioration prediction is to be performed for the equipment for which maintenance extension consideration is to be performed, as will be described in detail later with reference to FIGS.

[0034] In step S103, the processing unit 110 performs degradation prediction and life extension for the parts selected in step S102. By predicting the amount of degradation of the parts, it is examined whether it is possible to extend the life of the parts. By extending the life of the parts, it becomes possible to postpone the implementation of equipment maintenance tasks, and maintenance tasks can be implemented at more effective timing. Details will be described later with reference to FIGS. 5 to 7.

[0035] In step S104, the processing unit 110 examines whether the extended maintenance cycle is within an acceptable range from the viewpoint of risk. Details will be described later with reference to Fig. 8. In step S104, if the safety and economic risks of the extended maintenance cycle are not within an acceptable range (step S104; No), the process returns to step S103, and if the safety and economic risks of the extended maintenance cycle are within an acceptable range (step S104; Yes), the process proceeds to step S105.

[0036] In step S105, the processing unit 110 applies the maintenance cycle determined to be within the allowable range and optimizes the regular inspection plan, as will be described in detail later with reference to FIG.

[0037] In step S106, the work process optimization support device WPO (see FIG. 11) examines whether the optimized periodic inspection plan is feasible, as will be described in detail later with reference to FIGS.

[0038] If it is determined that the regular inspection plan can be carried out (step S106; Yes), the process proceeds to step S107, and if it is not determined that the regular inspection plan can be carried out, the process returns to step S105.

[0039] In step S107, the processing unit 110 performs a regular inspection, collects various performance data, and feeds back the data to help improve the regular inspection plan for the next and subsequent inspections.

[0040] When planned maintenance is carried out, data that will become maintenance results is acquired, such as instrumentation of actual work time and acquisition of various amounts of deterioration of parts to be maintained. To support the selection of equipment and parts to be acquired, the system supports implementation by displaying the data acquisition method and required time from the database. The data acquired in this way is stored in the database and fed back into consideration of extending the maintenance cycle from the next time onwards and the creation and consideration of regular inspection plans. Then, return to step S101.

[0041] The main steps are described in detail below. <Details of Step S102> Fig. 3 is a flowchart showing the parts selection process S300 for predicting deterioration of equipment for which an extension of the maintenance cycle is being considered. Fig. 3 shows details of step S102 in Fig. 2. In Fig. 3, the left column shows the processing of the maintenance plan support device 100, and the right column shows the processing of the maintenance planner (reviewer).

[0042] The parts selection process S300 analyzes the type of deterioration that determines the maintenance cycle of the equipment in order to extend the maintenance cycle of the equipment. The maintenance cycle of the equipment is set so that the functions and performance required for the equipment can be maintained. When considering the parts that make up the equipment, it can be thought that the maintenance cycle of the equipment is determined based on the most fragile part based on the role of the equipment.

[0043] In step S301, a maintenance planner such as a power company or manufacturer that performs maintenance determines equipment for which an extension of the maintenance cycle is to be considered. In step S302, the maintenance plan supporting device 100 extracts deterioration-related data for each part of the selected device (target device) from the database. In step S303, the maintenance plan support device 100 extracts, from the extracted parts, parts that affect the maintenance cycle of the equipment, their deterioration mechanisms, and the lifespan until loss of function, and displays the extraction results and the maintenance tasks corresponding to the parts as shown in Figure 4.

[0044] Fig. 4 is a diagram showing an example of the parts that affect the maintenance cycle of equipment, their deterioration mechanisms, and the lifespan until loss of function, etc. that are extracted and displayed. Fig. 4 shows an example of a ball valve, which is one of the many types of valves used in nuclear power plants. The maintenance plan support device 100 extracts data related to the deterioration of the ball valve from the database device 200, and displays the parts that affect the maintenance cycle, their deterioration mechanisms, and the lifespan until loss of function, etc., on the output unit 140.

[0045] This allows maintenance planners to consider extending the maintenance intervals of components that have a short lifespan before losing function.

[0046] Returning to FIG. 3, in step S304, if it is determined in step S303 that there is insufficient information, the maintenance planner adds information about the part from the design data of the equipment or the like.

[0047] In step S305, the maintenance plan support device 100 compares the information extracted in step S303 with the degradation mode information extracted from the PMBD and outputs the result. The components to be considered, their degradation mechanisms, and the effects of degradation are compared with the Failure Modes in the PMBD. The component boundary of the target equipment is checked to see if there are any differences in the scope of consideration for the extracted equipment. Furthermore, the component (Failure Location), degradation mechanism, and degradation influence, which indicate the degradation mode for the equipment, are compared.

[0048] In step S306, the maintenance planner examines the results of the comparison to determine whether there are any omissions in the parts or deterioration modes that should be considered. If there are any omissions (step S306; No), they are examined to determine whether they should be considered, and if necessary, return to step S304 and refer to the equipment design data, PMBD, etc. to acquire or supplement data on the impact of part deterioration and deterioration modes. In addition, the task objectives and task contents of the maintenance tasks for the PMBD equipment are compared with the maintenance tasks for the equipment whose maintenance cycle is to be extended, and it is confirmed that there are no differences in the objectives and scope of the maintenance tasks. If there are any differences, it is determined whether they need to be taken into consideration. If the comparison determines that there are no omissions (step S306; Yes), proceed to step S307.

[0049] In step S307, the maintenance plan supporting device 100 displays on the output unit 140 the maintenance cycle that can be extended by extending the life of each part and the amount of cost reduction when this is applied.

[0050] In step S308, the maintenance planner considers whether extending the lifespan is effective in reducing maintenance costs. Since equipment is usually made up of a combination of multiple parts, for example, a target extension for a certain maintenance cycle is determined. The maintenance planner determines whether extending the lifespan of part A will contribute to extending the maintenance cycle and whether it will be effective in reducing costs. The maintenance planner also determines whether extending the lifespan of part A and then part B will be even more effective in reducing costs. The maintenance planner also takes into account the cost of the study and decides which parts to consider extending their remaining lifespan.

[0051] In step S309, the maintenance plan support device 100 checks whether the extended maintenance cycle satisfies domestic regulatory requirements. If a cost-effective cycle extension would clearly exceed regulatory requirements, the system does not consider extending the cycle.

[0052] In step S310, the maintenance planner determines the parts for which degradation prediction and life extension study will be performed. That is, since the equipment parts for which extension of the maintenance tasks can be expected through life extension have been selected, the maintenance planner can decide to perform a life extension study on these parts.

[0053] <Details of Step S103> Fig. 5 is a flowchart showing the maintenance cycle extension consideration process S500. Fig. 5 shows details of step S103 in Fig. 2. In Fig. 5, the left column shows the processing of the maintenance plan support device 100, and the right column shows the processing of the maintenance planner (reviewer).

[0054] There are various environmental factors that cause breakdowns and functional degradation of equipment and parts, and these generally accumulate as degradation over time. Furthermore, it is believed that there are multiple factors involved. By predicting the amount of degradation of these factors, it is possible to propose more accurate maintenance cycles. The amount of degradation refers to measured or estimated values ​​resulting from the material, mechanical, and electrical degradation of parts. The characteristics of such changes in degradation over time are identified and collected based on prior degradation tests, simulations, and measurements on actual equipment, and then stored in a database.

[0055] In step S501, the maintenance planner determines the parts for which remaining life extension will be considered. In principle, the parts to be considered are those determined in step S310 of FIG.

[0056] In step S502, the maintenance plan supporting device 100 extracts degradation-related data (degradation mechanism of the part, degradation detection method, degradation test data, failure record data, etc.) of the target part from the database.

[0057] In step S503, the maintenance plan support device 100 displays on the output unit 140 the deterioration amount that can be used to predict deterioration of the target part from the database, as well as the deterioration amounts of parts that have similar properties such as shape and material.

[0058] In step S504, the maintenance planner determines a representative deterioration amount for the component for which deterioration prediction is to be performed. The representative deterioration amount is selected based on a deterioration amount that allows for more accurate deterioration prediction, such as one that has a high correlation with deterioration, allows for easy measurement and recording on-site, and is easy to predict because the change in deterioration amount is linear over time. Note that more than one representative deterioration amount may be selected at this time. The maintenance plan support device 100 also assists in the selection of a highly accurate representative deterioration amount by referencing deterioration trend data for similar conditions in terms of the type, material, shape, environmental conditions, required performance, etc. of the target component in the database.

[0059] In step S505, the maintenance plan support device 100 creates deterioration trend data that predicts the relationship between the selected representative deterioration amount and changes in deterioration amount over time, based on the actual machine measurement data, test data, environmental conditions, etc. That is, the maintenance plan support device 100 creates the deterioration trend data based on the change characteristics of the representative deterioration amount and the environmental conditions of the equipment, using the deterioration test data (EQ test data), on-site measurement data (as-found data), etc. as the basis.

[0060] In step S506, the maintenance planner checks the deterioration trend data, corrects the data, manages margins, etc., and determines the deterioration trend data.

[0061] In step S507, the maintenance plan supporting device 100 creates a recommended value for the deterioration amount for maintenance implementation based on the importance of the equipment, displays it on the output unit 104, and proposes a maintenance cycle.

[0062] The created degradation trend data allows for prediction of deterioration over time for each component. Here, the maintenance execution degradation amount is calculated, taking into account the component's importance and indicating when a specified value of degradation is reached and maintenance tasks should be performed. The importance of a component can be divided into safety-related and economic-related importance. For example, safety-related importance is evaluated based on the component's contribution to the safety of the equipment in which it is located, as well as the accuracy of detecting and checking the degradation amount. Economic importance is evaluated based on factors such as the cost of performing maintenance tasks for the component and the impact of loss of functionality of the equipment due to component degradation on power generation. Taking these factors into consideration, the maintenance execution degradation amount that provides the best economical performance while ensuring safety is determined. If this extends the lifespan of the component, the maintenance task execution cycle for the equipment can be extended.

[0063] Fig. 6 is a flowchart showing the process S600 for setting a recommended deterioration amount for implementing maintenance of a device based on the importance of the device. Fig. 7 is a diagram showing an image of setting a recommended deterioration amount for implementing maintenance of a device.

[0064] 6, the maintenance plan support device 100 determines whether the safety importance of the equipment is high (step S601), and if the safety importance of the equipment is high (step S601; Yes), it sets a maintenance implementation deterioration amount by taking a safety margin from the deterioration amount at which the equipment required function decreases (step S602), and ends the processing. On the other hand, if the safety importance of the equipment is not high (step S601, No), it proceeds to step S603.

[0065] The maintenance plan support device 100 determines whether the degradation or loss of equipment function will affect economic efficiency (step S603), and if it will affect economic efficiency (step S603; Yes), it sets an appropriate maintenance implementation deterioration amount taking into account the impact on economic efficiency and the cost of the maintenance task (step S604), and ends the process. On the other hand, if it will not affect economic efficiency (step S603; No), it proceeds to step S605. In step S605, the maintenance plan support device 100 sets the deterioration amount that is expected to result in loss of function as the maintenance implementation deterioration amount, and ends the process.

[0066] Referring to Figure 7, the setting in step S602 means that since the equipment is related to safety-critical functions, it should be maintained with a measurement (prediction) margin (see circle), the setting in step S604 means that maintenance should be performed before a failure or deterioration in function occurs (see triangle), and the setting in step S605 means that maintenance should be performed after a failure has been confirmed (see square).

[0067] Returning to FIG. 5, in step S508, the maintenance planner determines the amount of deterioration required for maintenance and the maintenance cycle with reference to the displayed recommended values.

[0068] In step S509, the maintenance plan supporting device 100 sets the time until the determined maintenance implementation deterioration amount is reached as the remaining life of the part, and stores the set in the database.

[0069] <Details of Step S104> FIG. 8 is a flowchart showing the gap analysis process S800 for maintenance importance by comparing PMBD and maintenance cycles. FIG. 8 shows details of step S104 in FIG. 2. In step S104, the maintenance plan support device 100 determines whether the safety and economic risks of the extended maintenance cycle are within an acceptable range. It is confirmed whether the extended maintenance cycle based on the set amount of deterioration in maintenance implementation satisfies domestic regulatory requirements. If it deviates from the regulatory requirements, the maintenance cycle is extended to the extent possible within the regulatory requirements. In addition, an explainability check is performed to see if the difference between the extended cycle and the previous maintenance cycle is correct. If the explainability is insufficient, it is examined whether it is possible to obtain information on the insufficient items and elements. If it is possible to obtain the information, the information is obtained and the maintenance cycle is extended.

[0070] In step S801, the maintenance importance gap analysis unit 112 (see FIG. 1) of the maintenance plan support device 100 extracts target equipment and component information. That is, the maintenance importance gap analysis unit 112 extracts the type of maintenance task, the execution period of the maintenance task, and the task purpose for the equipment of the same type as the equipment whose maintenance cycle has been extended.

[0071] In step S802, the maintenance importance gap analysis unit 112 compares the extended maintenance tasks and their cycles with the PMBD. The environmental conditions when the deterioration trend data was created, and the content and purpose of the maintenance tasks are extracted and compared with the PMBD. From the tasks in the PMBD, the task objective, task content, and eight patterns of classification of the equipment's environmental (operational) conditions - criticality (critical / non-critical), duty cycle (HI / LO), and service conditions (severe / mild) - as well as the maintenance cycles defined therein are extracted and compared.

[0072] In the PM (Preventive Maintenance) template, Criticality is divided into Critical and Non-Critical, Duty Cycle is divided into High and Low, and Service Conditions are divided into Severe and Mild, and eight patterns are classified based on the combination of these three items.

[0073] In step S803, the maintenance importance gap analysis unit 112 determines whether the compared maintenance cycles are Japan ≧ USA, and if Japan ≧ USA (step S803; Yes), proceeds to step S804, and if Japan < USA (step S803; No), proceeds to step S805. That is, the safety and economic importance are reevaluated from the maintenance cycle comparison result.

[0074] In step S804, if the domestic maintenance cycle is longer than the US maintenance cycle (domestic ≧ US), it is possible that the concepts of safety importance for the device in question differ. The maintenance importance gap analysis unit 112 performs a gap analysis of the differences in safety, such as the role of safety related to the device in Japan and the US, and the concepts of safety margin, for the device in question, and considers whether the setting of the maintenance implementation deterioration amount was optimal. In step S806, the maintenance cycle is redefined to ensure greater safety.

[0075] In step S805, if the maintenance cycle in Japan is shorter than in the United States (Japan < United States), it is possible that the approach to the importance of the economic efficiency of the equipment in question differs. A gap analysis is performed to determine the difference in approach to the economic efficiency of the plant, such as the introduction and operation costs, maintenance costs, and power generation risks of the equipment in question, and a review is conducted to determine whether the setting of the maintenance implementation deterioration amount was optimal. In step S806, the maintenance cycle is redefined to be more economical.

[0076] <Details of Step S105> Fig. 9 is a flowchart showing the cost optimization process S900 for the next regular inspection. Fig. 9 shows details of step S105 in Fig. 2. In step S105, the regular inspection plan is simulated and optimized.

[0077] To more effectively improve the economic efficiency of maintenance through the redefined equipment maintenance cycles, it is necessary not only to extend the cycles of each task but also to create implementation plans for efficient resource utilization. Nuclear power plants in Japan are required to shut down the reactor approximately once a year for periodic inspections (regular inspections). By appropriately developing equipment inspection plans based on these inspections during reactor shutdowns, it is necessary to minimize the duration of power generation outages at nuclear power plants and increase their capacity utilization rates. Furthermore, when performing maintenance tasks, ancillary work such as system isolation and the installation of scaffolding for high-altitude work may be required, which can require significantly more man-hours than the maintenance tasks themselves. By appropriately coordinating and planning these tasks, it is possible to optimize overall power plant maintenance costs.

[0078] For example, suppose there are two pieces of equipment A and B in the same area that require aerial scaffolding for maintenance tasks, with maintenance task execution cycles of five and six years, respectively. In this case, by estimating the long-term cost increase of reducing the maintenance task execution cycle of equipment B from six years to five years and the cost reduction resulting from the reduction in the number of aerial scaffolding installations, and selecting the least costly method, the overall maintenance cost can be optimized. However, such partial adjustments may also affect the duration of power generation outages, etc. When aiming for overall optimization, the number of items to be considered is enormous, and optimizing by hand would require a significant amount of work from highly skilled experts. Therefore, by using a system to assist in the organization of each item in a database and the optimization process, it is expected that the amount of planning work can be reduced.

[0079] First, in step S901, the processing unit 110 (see FIG. 1) extracts the equipment to be maintained and its maintenance task-related information. The equipment to be maintained is the equipment that is determined to require inspection at the next regular inspection according to its maintenance cycle. The maintenance task-related information includes the order of the maintenance tasks and incidental work, the time required for the work, the required resources, and their cost information.

[0080] In step S902, the processing unit 110 creates a tentative process based on the extracted maintenance task information and predicts the time required for this process as the plant downtime. The predicted plant downtime will be used as a reference time for later cost evaluation.

[0081] In step S903, the processing unit 110 calculates the cost of each maintenance task for the tentative process. The cost of each maintenance task is the sum of the cost of performing the maintenance task and the cost of any incidental work. If the same work contributes to multiple maintenance tasks, these costs are taken into consideration and allocated to each maintenance task.

[0082] In step S904, the processing unit 110 extracts a maintenance task that involves the same incidental work as the maintenance task scheduled to be performed in step S902 from the tentative process.

[0083] In step S905, the processing unit 110 simulates the increase or decrease in costs when the maintenance task cycle is performed earlier (advanced), as in the example described above. The cost increase or decrease takes into account the cost reduction due to the reduction in incidental work during the next regular inspection and thereafter, the cost increase due to the replacement of consumable parts, etc., earlier than the maintenance cycle, as well as the increase or decrease in the capacity factor (power generation amount) due to the increase or decrease in work resources and the increase or decrease in the plant shutdown period, and performs a long-term simulation to compare costs depending on the timing of the maintenance task. The processing unit 110 also has a function to extract, from the simulation results, maintenance tasks that are expected to have an impact on the execution of other maintenance tasks and incidental work and reduce costs when the cycle of the maintenance task is extended, as candidates for consideration of extending the maintenance cycle.

[0084] In step S906, the processing unit 110 extracts, from the simulation results, maintenance tasks that can reduce costs in the long term by advancing the execution of the maintenance tasks to the next regular inspection.

[0085] <Details of Step S106> FIG. 11 is a diagram showing the configuration of a work process optimization support device WPO according to this embodiment. FIG. 12 is a flowchart showing the work plan creation support process performed by the work process optimization support device WPO. FIG. 12 shows details of step S106 in FIG. 2. In step S106, it is examined whether the optimized periodic inspection plan is feasible. That is, the execution plan for the optimized maintenance tasks is converted into a process, and the support device reviews whether it can be carried out with the assumed resources and time period entered by the process creator. Feasibility is determined from the feasibility evaluation.

[0086] 11 is a diagram showing the configuration of a work process optimization support device WPO according to this embodiment. The work process optimization support device WPO has a processing unit 10, a memory unit 20, an input unit 30, an output unit 40, and a communication unit 50. The processing unit 10 has a work process optimization unit 11 and a work plan evaluation unit 12. The work plan evaluation unit 12 has functions such as evaluation of work time, evaluation of radiation exposure, extraction of pending items in the work plan, and comparison between the work plan and work performance. The memory unit 20 stores radiation exposure management information 21, process progress status 22, resource information 23, worker work proficiency 24, processing unit output information 25, etc.

[0087] The work process optimization support device WPO also has a database device 60, which is an external storage device. The database device 60 has a work basic information DB 61, a plant environment information DB 62, an inspection performance information DB 63, a worker information DB 64, a real-time update information DB 65, a new knowledge and countermeasures information DB 66, etc.

[0088] The information stored in each DB is explained below. The basic work information DB 61 is a DB of information required to perform work, including the conditions for performing the work, procedures, required resources, and the context of other work. The plant environment information DB 62 is a DB of information related to the worker's work environment, including structural information of the work area when an inspection is carried out, 3D-CAD information, dose distribution information, and scaffolding information during work. The inspection performance information DB 63 is a DB of information including the work process, detailed plans (work procedures) for each work, work content, work time, number of workers, worker work proficiency information, worker exposure information, and work execution result information from past inspections of nuclear plants, etc.

[0089] The worker information DB64 is a DB of information on worker skills and radiation exposure, including work experience information for individual and group workers engaged in inspection work, education and training results information, radiation management information, and information on acquired qualifications, etc. The real-time update information DB65 is a DB of information on ongoing work, including work progress information for ongoing inspections and worker exposure information. The new knowledge and countermeasures information DB66 is a DB of information on improvements obtained from sources other than past performance, including techniques and methods for improving inspection methods.

[0090] The processing unit 10 will now be described. The work process optimization unit 11 has the function of automatically creating a work process that satisfies the input conditions from a database containing basic information about the work, plant environment information, worker information, and inspection record information by specifying the conditions for each work related to process creation.

[0091] The work plan evaluation unit 12 predicts the work completion time and worker exposure dose from the created process using information from the database. The work plan evaluation unit 12 also has a function to display the comparison results of the work plan and past performance data in a work plan / performance comparison unit. Here, it has a function to suggest improvement items for the work plan, displaying items that are determined to have a large difference based on the comparison results as improvement items. Furthermore, the work plan evaluation unit 12 has a function to display and refer to related information including work procedures for simulations, structural data of the work location, and performance information on past identical and similar work.

[0092] Next, support for creating inspection plans and inspection processes for periodic inspections by the work process optimization support device WPO will be explained in more detail using the flowchart of the periodic inspection plan support process S230 in Fig. 12. Refer to Fig. 11 as needed. In Fig. 12, the left column shows the processing by the work process optimization support device WPO, and the right column shows the processing by the process creator.

[0093] <Detailed example 1: Support for periodic inspection planning> (Steps S200 to S202) The process planner determines the maintenance items to be performed during the next periodic inspection, and then determines the work items required to perform the maintenance items.

[0094] During regular inspections of nuclear power plants in Japan, the timing of maintenance tasks for the facilities and equipment that are subject to maintenance is determined based on the maintenance cycle set for them. This maintenance cycle varies depending on the type of facility and equipment, installation environment, function, etc., and maintenance must be carried out within an appropriate cycle.

[0095] Performing maintenance on each piece of equipment and machinery at each work cycle is the most efficient way to carry out maintenance tasks, but when inspecting areas that require a lot of preparatory work, such as setting up scaffolding or using large heavy machinery, preparing each time can be costly and time-consuming. When considering multiple regular inspections of nuclear power plants, appropriately adjusting the timing of work that requires specific preparatory work can be effective in shortening the regular inspection period and reducing worker exposure. The Work Process Optimization Support System (WPO) supports the selection of appropriate work timing.

[0096] The work process optimization support device WPO extracts and organizes work that has common work preparation items and is performed in related work areas from a database (DB). It extracts and organizes the execution history and inspection cycles of these tasks. For work that has common work preparation items and is performed in related work areas, information such as the preparation content, work area, maintenance cycle, and the chronological relationship of these tasks is displayed on the display device of the output unit 40. This information clarifies the maintenance tasks that require common preparation work for each task, and supports the consideration of the optimal implementation timing based on the cost required for the preparation work, the maintenance task cost, and its cycle. This information makes it possible to determine the work to be performed at the next regular inspection.

[0097] (Step S203) The process planner measures and collects on-site work information. He organizes information such as the area where workers prepare for work, the route they take, information on the structure of the area where they will be working, and information on the scaffolding that will be installed. As this information is used to consider work procedures, predict risks, and estimate radiation exposure, he obtains three-dimensional data such as 3D-CAD and information on dose distribution using gamma scans, etc., as needed. He organizes this information in the plant environment information DB62 and checks to see if there are any updates to this information.

[0098] (Step S204) The process planner collects maintenance performance data. This is performance data of past maintenance work, i.e., information such as past maintenance plans, performance data, and analysis data that contributes to improvements. This information is organized into the maintenance performance information, new findings, countermeasures, etc. information DB 66, and a check is made to see if this information has been updated.

[0099] (Step S205, Step S206) The process planner inputs the conditions for each task from the confirmed tasks (step 205). If a significant improvement in work efficiency is expected from improvements in equipment specifications or methods based on past performance, this information is entered so that it can be referenced in future evaluations and reviews, and is stored and organized in the basic task information DB 61 as necessary.

[0100] The Work Process Optimization Support System WPO creates an overall process based on the input information and information from the database. At this time, the Work Process Optimization Support System WPO supports the input of data by the process creator so that the number of workers required for each task, the required work time, and predicted radiation exposure can be referenced from past performance data, etc.

[0101] Thereafter, the work process optimization support device WPO organizes the constraints and sequential relationships in the execution of each task, creates a critical path, and schedules other tasks with a focus on leveling out the number of workers based on the critical path, thereby creating a work process (step 206).

[0102] Leveling the number of workers means minimizing changes in the minimum number of workers required to carry out work during periodic inspections (regular inspections) as the process progresses, in other words, minimizing the difference between the peak and bottom number of workers as much as possible. The work process optimization support device WPO visualizes changes in the number of workers required for the entire process using graphs, etc., and provides information to consider whether the implementation date can be moved forward or backward from the peak number of workers. To provide this support, the display device of the output unit 40 displays a diagram showing the time schedule and number of workers required for the entire process, as well as the constraints and chronological relationship of each task. Leveling the peak number of workers is expected to have the effect of reducing excess resources during periodic inspections.

[0103] (Step S207) The process planner secures the necessary personnel for the work based on the work process. The personal data of the secured workers is collected. This personal data includes each worker's work performance, qualifications, education and training records, and radiation management information, and is compiled into the worker information DB64 (securing the number of workers and collecting the workers' personal data).

[0104] (Step S208) The work process optimization support device WPO extracts information necessary for reviewing each work plan, such as the work number, work content, work procedure, number of people required for the work, required time for the work, predicted radiation exposure, work area, special skills required for the work, equipment required for the work, and tools required for the work (extracts information necessary for work plan review).

[0105] (Step S209) The work process optimization support device WPO evaluates the work plan for each work item based on the extracted information. The evaluation (review) of each work plan is based on the estimated work completion time and estimated radiation exposure for each work item. The work process optimization support device WPO compares the work time and estimated radiation exposure with those at the time of creating the overall process, and outputs the estimated work completion time and estimated radiation exposure as shown in the output images of Figures 13 and 14, identifying gaps and their causes as pending items, and supports the review of the work plan. The estimated work time T predicted by the review support is calculated as shown in equation (2).

[0106] W=T′×α′×β′ (1) T = W / (α × β) (2) X = T × I (3) Here, the workload based on past data is W, the past actual working time is T'(H), the work efficiency coefficient based on the past actual number of workers is α', the work proficiency coefficient of past workers is β', the estimated working time is T(H), the work efficiency coefficient based on the number of workers at the time of planning is α, the work proficiency coefficient at the time of planning is β, the estimated radiation dose of workers at the end of work is X(Sv), and the dose per unit time in the work space is I(Sv).

[0107] The work process optimization support device WPO calculates the workload W for each task number based on past data using equation (1). If more detailed data is available, it calculates the workload for each procedure number. The work process optimization support device WPO calculates the estimated work time T based on the workload using equation (2), and calculates the estimated radiation exposure X from the estimated work time using equation (3).

[0108] The work process optimization support device WPO creates work items for tasks where the work time varies significantly depending on resources other than workers (heavy machinery, etc.), and evaluates the estimated work time using separate simulations, etc.

[0109] When calculating estimated work time, changes in work efficiency due to the number of workers are taken into account. If there is a change in the number of workers from the past data used to calculate the workload, the impact of the increase or decrease in the number of workers on work productivity is taken into account as work efficiency coefficients α and α'. In addition, work proficiency is evaluated by evaluating the skills required for the work for each work group, and the impact on productivity is taken into account as work proficiency coefficients β and β'.

[0110] The change in the work efficiency coefficient depending on the number of workers and the work proficiency coefficient will be explained with reference to Figs. 15, 16 and 17, as it is necessary to take into account the nature of the work.

[0111] FIG. 15 is a diagram showing an example of how work efficiency changes with the number of workers. The explanation will refer to FIG. 11 as appropriate. As shown in FIG. 15, the way in which work efficiency changes with an increase in the number of workers can differ depending on the type of work. Graph 15A in FIG. 15 shows a case in which work efficiency increases with an increase in the number of workers. Graph 15B in FIG. 15 shows a case in which work efficiency increases with an increase in the number of workers but then saturates. Graph 15C in FIG. 15 shows a case in which work efficiency increases in a stepwise manner with an increase in the number of workers.

[0112] An example of a work efficiency coefficient based on the work efficiency shown in Fig. 15 is shown in Table 1. The left side of Table 1 corresponds to the graph indicated by reference numeral 15A in Fig. 15, and the right side of Table 1 corresponds to the graph indicated by reference numeral 15C in Fig. 15. [Table 1]

[0113] 16 is a flowchart showing the process S400 for determining the work efficiency coefficient based on the number of workers, which will be described with reference to FIGS. The processing unit 10 of the work process optimization support device WPO considers how the efficiency of the work to be evaluated changes with changes in the number of workers and sets a model (step S401). In considering this model of changes in the number of workers and work efficiency, if the work process optimization support device WPO has sufficient information in its database, it creates a model based on past data. If there is not enough data, it displays related information to support the process creator in considering the model.

[0114] The processing unit 10 sets the maximum and minimum number of workers required to perform the work (step S402: setting the upper and lower limits of the number of workers). By setting the upper and lower limits of the number of workers required in the physical configuration when performing the work, it is possible to prevent the work efficiency from being affected by assuming an infeasible number of workers at the work site. It is also possible to prevent inputting the number of workers incorrectly, work interruptions due to a shortage of workers at the site, or a significant excess of workers.

[0115] The processing unit 10 plans and determines the number of people to perform the work (step S403). Then, the processing unit 10 determines a work efficiency coefficient to be used for estimating the workload and work time from a model of changes in work efficiency depending on the number of workers (step S404).

[0116] Figure 17 is a flowchart showing the task proficiency evaluation process S700 for each task group. Description will be made with reference to Figure 11 as appropriate. Task proficiency is ranked, and the skill proficiency required for each task is evaluated. Required skills and standards are set for each task's characteristics, proficiency is ranked, and a task proficiency coefficient related to task efficiency is set. The task proficiency evaluation process S700 evaluates task proficiency, which affects task time, but if necessary, task quality can also be evaluated and reflected in the work plan.

[0117] The processing unit 10 of the work process optimization support device WPO displays basic information about the work on the display unit of the output unit 40 (step S701), and the process creator extracts the skills and qualifications required to perform the work (step S702). The work process optimization support device WPO can support the process creator in extracting the skills and qualifications required to perform the work.

[0118] The processing unit 10 displays the basic information of the work and past worker data on the display device of the output unit 40 (step S703), and the process planner evaluates and sets items that affect the work execution time based on the extracted skills and qualifications, past data, work simulations, etc. (step S704). The work process optimization support device WPO can support the evaluation and setting of items that affect the work execution time.

[0119] The processing unit 10 extracts past data and reference data and displays them on the display device of the output unit 40 (step S705). The process creator considers and sets the evaluation conditions for each evaluation item, taking into account the type of work, since the proportion of experienced and qualified workers required to improve work efficiency varies depending on the type of work (step S706).

[0120] The processing unit 10 extracts information about the workers in the work group in charge of the scheduled periodic inspection, and evaluates the work proficiency (step S707).

[0121] Table 2 shows an example of work proficiency coefficients based on work proficiency. The left side of Table 2 shows the case where work can be done individually, in the case of ultrasonic flaw detection inspection. The right side of Table 2 shows the case where work is done in a group, in the case of disassembling and inspecting equipment or replacing it. [Table 2] As explained above, the estimated task time can be calculated using equation (2) taking into consideration the task efficiency coefficient and task proficiency coefficient depending on the number of workers.

[0122] Returning to the processing of step S209 (see FIG. 12), the work process optimization support device WPO displays, in addition to the calculation results, an evaluation of whether the work can be carried out with the work time, number of workers, and planned exposure dose set for the overall process created in step S206 by comparing each term used in the calculation with the database, and displays the evaluation on the display device of the output unit 40 (evaluate the work plan). This evaluation result can support the review of pending items to determine whether measures are necessary to prevent delays or deterioration in quality in the planned overall process.

[0123] (Step S210, Step S211) The process planner reviews the plan for each task based on the evaluation results (step S210). If there are any pending issues regarding the feasibility of the planned tasks, the process planner decides to take measures for the pending issues, and implements the measures for the pending issues that are determined to require measures (step S211). If long-term measures such as data collection that will contribute to inspection work after the currently planned outage are considered, the process planner decides whether to implement them.

[0124] <Examples of measures to be implemented> (1) Assume that the worker's proficiency level is not sufficient for work that requires special skills or is complex and where knowledge and experience have a significant impact on work productivity. By providing education and work training before the implementation of periodic inspection work, the worker's proficiency level can be improved and the feasibility of completing the work as planned can be increased.

[0125] (2) If the dose rate in the work area is higher than expected and the radiation exposure is higher than planned, or if the cumulative radiation exposure of individual workers exceeds the tolerable range, it may be necessary to improve the radiation environment in the work area or change the worker's position. To improve the environment, consider chemical decontamination or installation of shielding in high-radiation areas in the work area, work preparation area, and travel routes, as well as improving water quality management methods.

[0126] (3) If the number of workers or work equipment is insufficient compared to the actual data, changes in worker placement and the addition of resources should be considered. If the cumulative radiation exposure of individual workers exceeds the allowable range even after implementing measures to improve the radiation environment, changes in worker placement should also be considered.

[0127] (4) For tasks that are frequently delayed or require rework, we will review the work procedures to increase productivity on-site and prevent mistakes. We will also provide information support by displaying work procedures on-site to ensure that work is carried out correctly and that no redoing is required.

[0128] When making the reassignment changes described in (2) and (3) above, the number of workers, their work proficiency, and the cumulative radiation exposure of each individual will change, so the changed work must be re-evaluated. However, the database device 200 and the work process optimization support device WPO can easily re-evaluate the work, reflecting the results of adjustments and countermeasures implemented during process optimization, which has the effect of making it easier to make detailed adjustments to reassignment. If it is determined that there is insufficient data to consider countermeasures, the necessary actual data will be considered. In addition, a plan to collect work data will be made with an eye toward inspections after the next regular inspection.

[0129] The work process optimization support device WPO evaluates the effects of each measure implemented in step S211 and reflects the results in the review of the work plan. The work process optimization support device WPO records the implementation details of the measures in the real-time update information DB65 as real-time update information so that the effects of the implemented measures can be evaluated at the end of the regular inspection, and records the evaluation results as inspection performance information for consideration of improvements in the next and subsequent regular inspections.

[0130] (Step S213, Step S214) The work process optimization support device WPO reevaluates the feasibility of the work with the effects of the measures reflected (reevaluation of the overall work process). If the process creator wants to change the overall process again based on the results of this evaluation (step S214; No), the process creator returns to step S205 and reexamines the overall process as currently created.

[0131] (Step S215) If the process creator determines from the re-review in step S214 that the overall process is sufficiently feasible (step S214; Yes), the process creator decides on the overall process in step S215.

[0132] Next, an example of step S102 and an example of step S103 will be described. <Example of Step S102 (Parts Determination Step)> Parts for which deterioration prediction is performed are selected for equipment for which the extension of maintenance cycles is being considered. From the large number and types of valves used in nuclear plants, equipment parts are selected using ball valves as an example.

[0133] The maintenance planning support device 100 extracts information related to the deterioration of the ball valve from the database and displays the parts that affect the maintenance cycle of the equipment, their deterioration mechanisms, and the lifespan until loss of function, as shown in FIG.

[0134] Furthermore, the degradation mechanism and degradation influence corresponding to the information extracted and displayed from the PMBD are compared with the PMBD's Failure Modes. First, the component boundary of the target equipment is checked to see if there are any differences in the scope of consideration for the extracted equipment. Then, the components (Failure Location), degradation mechanism, and degradation influence for which degradation modes are indicated for the equipment are compared and organized in a table similar to the degradation-related information shown in Figure 4 as a degradation analysis table, and the results of the comparison are displayed on the output unit 140 (see Figure 1) by arranging them horizontally or vertically.

[0135] That is, the maintenance plan support method of the maintenance plan support device that supports the creation of a maintenance plan for a nuclear plant includes a first step in which, in a parts determination step, the parts / locations, degradation mechanisms, and degradation influences, which are maintenance items for equipment for which an extension of the maintenance cycle is being considered, are extracted and set as first information, and a second step in which, for the equipment for which an extension of the maintenance cycle is being considered, items including Failure Location, Degradation Mechanism, and Degradation Influence, which are organized in the PMBD (Preventive Maintenance Basis Database) of EPRI (Electric Power Research Institute), are extracted and set as second information, and the first information and the second information are compared for each item, and the comparison results are output to an output unit, thereby making it possible to support the maintenance plan.

[0136] As a result of the comparison, it is examined whether there are any omissions in the parts or degradation modes that should be considered. If there are any omissions, it is examined whether they should be considered, and if it is determined that they are necessary, data on the impact of part degradation and degradation modes is acquired or supplemented by referring to the equipment design data and PMBD. In addition, the maintenance tasks, task objectives, and task content of the PMBD equipment are compared with the maintenance tasks of the equipment targeted for maintenance cycle extension, and it is confirmed that there are no differences in the objectives and scope of the maintenance tasks. If there are any differences, it is examined whether they need to be taken into consideration, and the maintenance method and scope are revised as necessary.

[0137] Next, the database is used to extract and display the possible maintenance intervals and cost savings that result from extending the lifespan of each component. The effectiveness of extending a component's lifespan in reducing maintenance costs is examined. For example, the extent to which extending the lifespan of a component's gasket contributes to extending the maintenance interval of the corresponding maintenance task is determined, and the effectiveness of cost reduction is assessed. Furthermore, equipment typically consists of multiple components, and maintenance tasks target multiple components. For example, assume that the maintenance interval for the gasket, bolts, and structural connectors in Figure 4 is set to five years. When extending this maintenance interval, these three components must be considered. For example, if the gasket's lifespan is set to five years, the bolt's lifespan is seven years, and the structural connector's lifespan is ten years, then extending the maintenance interval must first consider the gasket's lifespan. If the gasket's lifespan is extended to seven years or more, the maintenance interval can be extended to seven years. In this way, the lifespans of all components subject to a maintenance task must be considered.

[0138] In addition, a target is set for the extent to which a maintenance task should be extended in order to effectively extend the maintenance cycle, and the cost required to achieve this is compared with the expected cost reduction from extending the maintenance cycle. This is a study that contributes to the optimization of regular inspection plans, and when other work incidental to the implementation of a maintenance task is required, a significant impact can be expected from the reduction in man-hours due to the extension of the maintenance cycle by carrying out the work at the same time, and this study is particularly carried out for maintenance tasks that have incidental work in common with other maintenance tasks.

[0139] Confirm whether the maintenance interval after extension to the target interval is compatible with domestic regulatory requirements. If extending the interval in a cost-effective manner clearly exceeds regulatory requirements, change the target maintenance interval and reconsider the cost, or do not consider extending the life of the part. Based on the above considerations, the equipment for which the life extension of equipment parts will be considered will be selected.

[0140] <Example of Step S103 (Cycle Proposal Step)> This will be explained using the packing shown in Figure 4 as an example. For example, let's consider a case where we focus on a packing made of a polymeric material used in a valve joint, and predict the amount of deterioration at a certain location, deterioration trend data, and remaining lifespan. The functional requirement for this packing is to prevent internal fluid from leaking from the joint, and the remaining lifespan while maintaining the functional requirement is predicted based on the deterioration trend data.

[0141] First, data related to packing deterioration is extracted. The data related to deterioration includes the packing deterioration mechanism, deterioration effects, deterioration detection methods, maintenance performance, usage environment information, material data, etc. From the extracted information, the amount of deterioration to be used to create packing deterioration trend data is determined.

[0142] Deterioration can be caused by several environmental factors, such as the pressure at the joints of the piping and valves in which the packing is used, the influence of the fluid (temperature, chemical reactions), and the influence of radiation.When used in a nuclear power plant, the environmental conditions are generally constant whether the system in which the part is used is operating or not, so deterioration can be considered to be correlated with changes over time during operation.

[0143] There are various methods for checking the degradation of polymer materials, such as measuring compression set and hardness, but when checking the degradation at a nuclear power plant, it is preferable to use a method that is simple and has a high correlation with performance degradation, from the perspective of reducing the burden on workers and radiation exposure.It is also preferable that the measurement be non-destructive.

[0144] Figure 10 shows an example of time changes in physical quantities that correlate with equipment performance, with the graph labeled 10A being for breaking elongation and the graph labeled 10B being for functional group content. Both graphs 10A and 10B can be used as degradation quantities to evaluate and predict part degradation, but it is desirable to use a physical quantity that shows a greater correlation with performance degradation and whose change in degradation quantity over time is easier to predict. In the example of Figure 10, it can be said that degradation prediction based on functional group content shown in graph 10B is easier to predict based on time changes than breaking elongation shown in graph 10A.

[0145] In this example, infrared absorption spectra are measured for polymeric materials using infrared spectroscopy or the like, and the change in the amount of functional groups due to the measured oxidative degradation is used as a representative amount of degradation, and the current amount of degradation is determined based on the ratio to the limit value of the mechanical properties. Since many polymeric materials in nuclear plants are constantly exposed to high doses of radiation, when materials for general products are used, periodic inspections must be conducted at short intervals. It is known that oxidative degradation of polymeric materials is accelerated in a radiation environment. Since the acceleration of oxidative degradation largely depends on the absorbed dose, there is a proportional relationship between the usage time of polymeric materials in a radiation environment and the amount of degradation.

[0146] Degradation trend data is created by the support device based on the time-dependent changes in the amount of degradation in test data and actual equipment measurement data, as well as the environmental conditions involved. The degradation trend data for the same or similar parts is automatically estimated by converting the differences in environmental conditions into percentages based on the degradation characteristics obtained under each environmental condition, including the test and actual equipment measurement data, and the degradation trend data is displayed along with the differences between these conditions. The examiner can refer to this data and make corrections or set margins as necessary to create the degradation trend data.

[0147] Because deterioration trend data makes it possible to predict component deterioration based on changes in the amount of deterioration over time, the timing of performing maintenance tasks for a component is determined based on the importance of the component. When a predetermined amount of deterioration is reached based on the deterioration trend data, the performance of the packing deteriorates. Further deterioration increases until a certain level is reached, resulting in a loss of functionality. The timing of maintenance is appropriately selected based on the performance required of the packing. For example, the degree to which the required function of the packing (fluid leakage prevention) needs to be ensured is determined by the importance of the component. Fluid leakage from the equipment containing the packing may affect plant safety, reduce power generation, or otherwise have no impact on the economy, or a minor leak may have no impact. It is desirable to perform maintenance on these packings at an appropriate level of deterioration based on their respective importance. The importance required of the packing can be determined based on the required functions and their importance for the equipment and system. In this embodiment, the amount of deterioration (lifespan) required to perform a maintenance task for a component is displayed as a recommended value based on the importance of the equipment's safety and economy, as shown in Figure 4. At this time, the resolution of the deterioration amount, the minimum detectable deterioration amount, etc. are displayed to assist the maintenance planner in determining the deterioration amount for which maintenance should be performed.

[0148] Furthermore, a cost comparison for carrying out maintenance on the target part is displayed. For example, when multiple maintenance tasks for a certain part can be selected, such as comparing the costs of maintenance performed before a failure and replacing the part after a failure, the method with the lowest cost can be selected, and the limit value of the deterioration amount to which that method can be applied can be set as the maintenance deterioration amount from the deterioration trend data.

[0149] By comparing the characteristics of the deterioration trend data and maintenance costs, and appropriately setting the timing for performing maintenance tasks based on the amount of deterioration required for maintenance, safety can be ensured and maintenance costs can be reduced.

[0150] From this information, the maintenance planner determines the amount of deterioration that requires maintenance. The determined amount of deterioration that requires maintenance is used to determine the lifespan of the part, and the time from the present until the amount of deterioration that requires maintenance is reached is used as the remaining lifespan. In addition, the execution cycle of the maintenance task corresponding to the part whose time until maintenance has been extended is extended. The lifespan, remaining lifespan, and new maintenance cycle of these parts are recorded in a database.

[0151] As described above, the maintenance plan support method of this embodiment is a maintenance plan support method for a maintenance plan support device that supports the creation of a maintenance plan for a nuclear power plant, and includes a parts determination step (step S102) of determining parts for which deterioration prediction is performed for equipment for which extension of the maintenance cycle is being considered when creating a maintenance plan, and a cycle proposal step (step S103) of determining deterioration trend data and a maintenance implementation deterioration amount for the determined parts and proposing a maintenance cycle based on the deterioration trend data and the maintenance implementation deterioration amount. This makes it possible to appropriately set the maintenance implementation timing for the maintenance plan for the nuclear power plant.

[0152] The maintenance planning support method further includes a comparison step (e.g., step S104, step S802) of comparing the proposed maintenance cycle with the maintenance cycles organized in the PMBD (Preventive Maintenance Basis Database) of the Electric Power Research Institute (EPRI).

[0153] The parts determination step has a first step of extracting the maintenance items, such as parts and locations, degradation mechanisms, and degradation influences, for the equipment for which the extension of the maintenance cycle is being considered and setting them as first information, and a second step of extracting items including Failure Location, Degradation Mechanism, and Degradation Influence, which are organized in the PMBD (Preventive Maintenance Basis Database) of the Electric Power Research Institute (EPRI), for the equipment for which the extension of the maintenance cycle is being considered, and setting them as second information.The first information and second information are compared for each item, and the comparison results are output to an output section, thereby supporting maintenance planning.

[0154] In the cycle proposing step, when determining the maintenance implementation deterioration amount, a maintenance implementation deterioration amount that enables more reliable prediction from information including the environmental conditions, required performance, material, and shape of the part can be selected as the representative deterioration amount.

[0155] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, or the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment can be added, deleted, or replaced with other configurations. Furthermore, the above-described configurations, functions, processing units, processing means, etc. may be implemented in hardware, in part or in whole, by designing, for example, an integrated circuit. Furthermore, the above-described configurations, functions, etc. may be implemented in software, by a processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function can be stored in memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD. [Explanation of symbols]

[0156] 10 Processing section 11 Work Process Optimization Department 12 Work Plan Evaluation Department 20 Memory section 30 Input section 40 Output section 50 Communications Department 60 Database Device 61 Basic work information DB 62 Plant Environmental Information DB 63 Inspection performance information DB 64 Worker Information DB 65 Real-time update information DB 66 Information database of new findings and countermeasures 100 Maintenance planning support device 110 Processing section 111 Maintenance cycle extension part 111A part determination processing unit (part determination unit) 111B Period proposal processing unit (period proposal unit) 112 Maintenance Criticality Gap Analysis Department 120 Storage section 121 Equipment Deterioration Analysis 122 Maintenance Task List 123 Equipment maintenance implementation deterioration amount setting information 124 Processing unit output information 200 Database Device 210 Deterioration-related DB 220 Equipment Importance Related DB 230 Regulatory-related DB 240 Maintenance task related DB 250 EPRI PMDB related databases S100 Maintenance planning support processing S230 Periodic inspection planning support processing S300 Parts selection process S400 Work efficiency coefficient determination process S500 Maintenance cycle extension review process S600 Setting process for recommended deterioration value for equipment maintenance S700 Work proficiency evaluation process for each work group S800 Maintenance Importance Gap Analysis Processing WPO work process optimization support device

Claims

1. A maintenance plan support method for a maintenance plan support device that supports the creation of a maintenance plan for a nuclear power plant, comprising: The processing unit of the maintenance plan support device a parts determination step of extracting parts of a device for which the extension of the maintenance cycle is to be considered when making a maintenance plan from the database, extracting parts that affect the maintenance cycle of the device and deterioration-related information from the extracted parts, and extracting parts for which deterioration prediction is to be performed; a cycle proposing step of determining deterioration trend data and a maintenance implementation deterioration amount for the extracted parts, and proposing a maintenance cycle based on the deterioration trend data and the maintenance implementation deterioration amount.

2. The maintenance plan support method further includes: The processing unit has a comparison step of comparing the proposed maintenance interval with maintenance intervals organized in the Electric Power Research Institute (EPRI) Preventive Maintenance Basis Database (PMBD).

2. The maintenance planning support method according to claim 1.

3. In the part determination step, a first step in which the processing unit extracts parts / sites, deterioration mechanisms, and effects of deterioration, which are maintenance items, for the equipment for which extension of the maintenance cycle is to be considered, and sets the extracted items as first information; a second step of extracting items including Failure Location, Degradation Mechanism, and Degradation Influence, which are organized in the Preventive Maintenance Basis Database (PMBD) of the Electric Power Research Institute (EPRI), from the equipment for which the extension of the maintenance cycle is to be considered, and setting the extracted items as second information; The first information and the second information are compared for each item, and the comparison results are output to an output unit, thereby supporting a maintenance plan.

2. The maintenance planning support method according to claim 1.

4. In the cycle suggestion step, When determining the maintenance implementation deterioration amount, the processing unit selects, as a representative deterioration amount, a maintenance implementation deterioration amount that enables a more reliable prediction from information including the environmental conditions, required performance, material, and shape of the part.

2. The maintenance planning support method according to claim 1.

5. In the cycle suggestion step, The processing unit measures the amount of functional groups in the polymer material used in the determined part by infrared spectroscopy to check for part deterioration, and evaluates deterioration based on this.

2. The maintenance planning support method according to claim 1.

6. In the part determination step, When determining components for which deterioration prediction is to be performed for the equipment for which extension of the maintenance cycle is to be considered, the processing unit focuses on the components that constitute the equipment when considering the maintenance cycle of the equipment, and identifies components that affect the maintenance cycle based on the purpose and implementation range of the maintenance task.

2. The maintenance planning support method according to claim 1.

7. In the part determination step, The processing unit compares the extracted part and deterioration-related information with deterioration mode information extracted from the PMBD (Preventive Maintenance Basis Database) of the EPRI (Electric Power Research Institute), and outputs the comparison result to the output unit.

2. The maintenance planning support method according to claim 1.

8. A maintenance plan support device that supports the creation of a maintenance plan for a nuclear power plant, a parts determination unit that, when making a maintenance plan, extracts parts of the equipment from a database for which an extension of the maintenance cycle is to be considered, extracts parts that affect the maintenance cycle of the equipment and deterioration-related information from the extracted parts, and extracts parts for which deterioration prediction is to be performed; a cycle proposal unit that determines deterioration trend data and a maintenance implementation deterioration amount for the extracted parts, and proposes a maintenance cycle based on the deterioration trend data and the maintenance implementation deterioration amount.

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