JP7458297B2 - Maintenance support method and maintenance support device - Google Patents

Description

The present invention relates to a maintenance support method and a maintenance support device related to a maintenance plan in a nuclear power plant.

Maintenance of each piece of equipment related to nuclear power plants in Japan is carried out based on a unique chart that summarizes maintenance methods, maintenance cycles, etc.

Patent Document 1 states that by reviewing the template contents, it is possible to provide an equipment management support system that can be expected to be operated with high convenience. The equipment management support system is an equipment management support system that issues inspection and maintenance work orders for asset equipment and stores the inspection and maintenance results in an equipment information database, and comprehensively monitors the status of asset equipment and its surroundings. A health index database that is grasped, quantified, and stored as a health index, and the grasped health index is used as the actual condition of the asset equipment, and compared with the expected maintenance effect estimated from the condition at the time of installation or previous inspection/maintenance. , a comparison calculation function that determines differences in asset and equipment status, a work knowledge database that acquires and stores the work knowledge of veteran workers, and a work change point for inspection and maintenance according to differences in work knowledge or asset and equipment status. It has a maintenance process update function that extracts and reflects the information in the equipment information database, and a work order issuing function that issues inspection and maintenance work orders using the information in the equipment information database that stores changes in inspection and maintenance work. .

In Patent Document 2, a huge number of alternatives are divided into a plurality of groups as a maintenance planning support method. The criteria for grouping differs depending on the decision-making problem, but in a problem of drawing up an inspection plan for valves in a nuclear power plant, the groups are grouped by system (for example, recirculation system, etc.) that makes up the plant. Next, for all the divided groups, the overall importance of the alternatives is determined using a decision-making method. Next, the importance of the alternatives in each group is standardized using the importance of the standard alternative, and the common importance of all the alternatives is determined. Finally, it is stated that the priority of maintenance work is determined from the ranking based on the importance of the alternatives.

JP 2016-189088 A Japanese Patent Application Publication No. 6-110872

There has been a demand for higher reliability maintenance based on risks and equipment deterioration than the maintenance plans using the methods of Patent Documents 1 and 2.

In the United States, the overall utilization rate of nuclear power generation facilities was in the 70% range from the 1980s to the 1990s. Subsequently, in the 2000s, the utilization rate of nuclear power generation facilities in the United States was raised to 90% through plant modifications, maintenance inspections, and more efficient refueling operations. One factor contributing to this is reform of conservation regulations and processes. It is known that in the United States, a standard template for equipment maintenance has been developed, which has led to more effective and efficient equipment maintenance activities. Even in Japan, the occupancy rate from 1990 to 2000 has been around 80%. More reliable and efficient maintenance activities are required.

The present invention is an invention for solving the above-mentioned problems, and aims to provide a maintenance support method and a maintenance support device that allow highly reliable and efficient maintenance activities for equipment to be maintained at a nuclear power plant. purpose.

In order to achieve the above object, the maintenance support method of the present invention is a maintenance support method for a maintenance support device that supports a maintenance plan for equipment to be maintained in a nuclear power plant, wherein the processing unit of the maintenance support device includes:
A first step of extracting items including current maintenance items such as importance classification, frequency of use of the equipment, and conditions of use of the equipment for the equipment to be maintained as first information; A second step of extracting items including Criticality, Duty Cycle, and Service Conditions organized in the PMBD (Preventive Maintenance Basis Database) of Electric Power Research Institute as second information, and combining the second information with the first information. and a comparison step of comparing the information item by item , and outputting the comparison result in the comparison step . Other aspects of the present invention will be explained in the embodiments described below.

According to the present invention, it is possible to provide a maintenance support method that enables highly reliable and efficient maintenance activities for equipment to be maintained at a nuclear power plant.

1 is a diagram showing a configuration of a maintenance support device according to an embodiment of the present invention; 1 is a flowchart showing an overview of a maintenance support method according to the present embodiment. It is a diagram showing PMBD maintenance information and domestic plant maintenance information. It is a flowchart showing a comparison, gap analysis, and re-evaluation method. FIG. 3 is a diagram illustrating an example of a comparison between PMBD maintenance information and domestic plant maintenance information. 7 is a flowchart illustrating safety reevaluation processing. 13 is a flowchart showing a process of reevaluating economic efficiency. FIG. 3 is a diagram showing causes of gaps depending on patterns of gaps between maintenance methods and maintenance cycles. It is a flowchart which shows the process (step S17A) of re-evaluation of a maintenance method and cycle. 13 is a flowchart showing a process of reevaluating a maintenance method and cycle (step S17B).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a diagram showing the configuration of a maintenance support device 100 according to this embodiment. The maintenance support device 100 includes a processing section 10, a storage section 20, an input section 30, an output section 40, and a communication section 50. The processing unit 10 includes a comparison information extraction unit 11, a comparison unit 12, an importance determination unit 13, a safety evaluation unit 14, an economic evaluation unit 15, an analysis unit 16, a redefinition unit 17, and the like.

The comparison information extraction unit 11 extracts maintenance information from EPRI's PMBD 200 and a DB 210 owned by a US electric power company, and stores it as PMBD output information 21. Further, the comparison information extraction unit 11 extracts maintenance information from a DB 220 held by a domestic electric power company and a DB 230 held by others such as a manufacturer, and stores it as domestic plant information 22.

EPRI (Electric Power Research Institute) is an American electric power research institute. PMBD (Preventive Maintenance Basis Database) is a database that aggregates PM (preventive maintenance) templates created for each specific device under EPRI.

The PMBD output information 21 that stores the output information includes maintenance-related information (Criticality, Duty Cycle, Service Conditions, Task (maintenance method), Baseline (maintenance cycle), Failure Mode) for domestic maintenance targets. It is a database of information extracted for comparison with equipment.

The DB 210 owned by the US electric power company is a database that stores information on which PM template to use and how to classify equipment when the US electric power company performs equipment maintenance.

The DB 220 held by domestic electric power companies is a database that stores maintenance activities of power generation plants managed by domestic electric power companies and design and test data of equipment related to maintenance.

The DB 230 owned by a manufacturer or the like is a database that stores information provided by equipment to be maintained and organizations that design and manufacture equipment of the same type. Domestic plant information 22 that stores outputted information regarding domestic plants is a database of information extracted for comparison with PMBD output information 21.

The comparison unit 12 compares the PMBD output information 21 (second information) and the domestic plant information 22 (first information).

The importance determining unit 13 determines whether or not the importance of maintenance in Japan is higher than that in the United States, based on the comparison results. The safety evaluation unit 14 focuses on safety and reviews the importance of the equipment. The economic efficiency evaluation unit 15 reviews the importance of the equipment by focusing on economic efficiency. The analysis unit 16 performs a gap analysis between the maintenance method and the maintenance cycle, and selects a redefined flow. The redefinition unit 17 evaluates and redefines the maintenance method and maintenance cycle in consideration of the reviewed importance.

The memory unit 20 stores PMBD output information 21, domestic plant information 22, extraction table 23 (see Figure 3), comparison table 24 (see Figure 5), maintenance method/cycle gap analysis table 25 (see Figure 8), etc.

In FIG. 1, the output unit 40 is a display or the like, which displays the execution status and execution results of processing by the maintenance support device 100. The input unit 30 is a device for inputting instructions to a computer, such as a keyboard or mouse, and inputs instructions such as starting a program. The processing unit 10 executes various programs stored in memory. The communication unit 50 exchanges various data and commands with other devices via the network NW. The external storage device 305 stores various data for the maintenance support device 100 to execute processing. The memory holds various programs and temporary data for the maintenance support device 100 to execute processing.

FIG. 2 is a flowchart showing an outline of the maintenance support method according to this embodiment.
In step S1, information regarding the current maintenance of equipment that is subject to maintenance at domestic nuclear power plants (importance classification, frequency of equipment use, equipment usage conditions, maintenance methods, maintenance cycles, deterioration mechanisms, etc.) is extracted.

In step S2, regarding the information extracted for the equipment to be maintained, maintenance information (Criticality, Duty Cycle, Service Conditions, Task (maintenance method), Baseline (maintenance cycle), Failure Mode ( Failure modes)) are extracted and compared for each item.

In order to make a comparison, it is necessary to allocate information corresponding to Criticality, Duty Cycle, and Service Conditions for equipment to be maintained at domestic nuclear power plants. In this embodiment, comparison can be made by obtaining the frequency of use of the device and the conditions of use of the device that are assumed at the time of design. The frequency of use of the device corresponds to the Duty Cycle, and the conditions of use of the device correspond to the Service Conditions. In addition, the level of importance of maintenance provided by the business operator is compared with Criticality. Maintenance methods, maintenance cycles, and failure modes are organized as the same items in both databases.

FIG. 3 is a diagram showing PMBD maintenance information and domestic plant maintenance information. FIG. 3 shows an example of the extraction table 23. The upper part of FIG. 3 is information based on PMBD (second information), and the lower part of FIG. 3 is information (first information) related to domestic plants.

Returning to FIG. 2, in step S3, a gap analysis is performed based on the comparison results for each item, and the maintenance importance classification for each device is redefined. In particular, we will focus on the patterns of differences between the domestic conservation importance classification and Criticality (Critical, Non-Critical) and RTF described in the EPRI PM template. Note that RTF (Run to Failure) refers to corrective maintenance, and is a method of repairing equipment after it is discovered that it has lost its function.

In step S4, the maintenance methods and maintenance cycles are evaluated according to the pattern of differences between domestic and US maintenance methods and maintenance cycles.

In step S5, the maintenance method and maintenance cycle for the equipment to be maintained are redefined based on the evaluation results.

FIG. 4 is a flowchart showing the comparison, gap analysis, and reevaluation method. In the maintenance support device 100, the comparison unit 12 determines the equipment of the maintenance target system input from the input unit 30 (see FIG. 1), extracts information for comparison from the PMBD output information 21 and the domestic plant information 22 ( Step S11), and the extracted information is compared (Step S12).

The importance determination unit 13 determines whether the domestic maintenance importance is higher than that of the United States based on the comparison result (step S13). If the domestic maintenance demand is equal to or higher than the US maintenance importance (step S13, Yes), the safety evaluation unit 14 reassess the importance of the equipment with a focus on safety (step S14: reassess safety), and then proceeds to step S16. If the domestic maintenance demand is lower than the US maintenance importance (step S13, No), the economic evaluation unit 15 reassess the importance of the equipment with a focus on economic efficiency (step S15: reassess economic efficiency), and then proceeds to step S16.

In step S16, the analysis unit 16 performs a gap analysis of the maintenance method and the maintenance cycle, and selects a redefinition flow. The redefinition unit 17 then evaluates and redefines the maintenance method and the maintenance cycle, taking into account the revised importance (step S17), and ends the series of processes.

This will be explained in more detail.
In order to compare the PMBD output information 21 and the domestic plant information 22, the comparison unit 12 compares each item of the domestic plant information 22 (importance classification, equipment usage frequency, equipment usage conditions, maintenance method, maintenance cycle, The items of the PMBD output information 21 (Criticality, Duty Cycle, Service Conditions, Maintenance Method, Maintenance Cycle, Failure Mode) are assigned to the PMBD output information 21 (Deterioration Mechanism).

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

In this embodiment, it is assumed that the comparison information extraction unit 11 classifies the devices according to the type of device and the system in which the device is used so that it can be compared with a standard pattern assigned in the United States.

The importance determination unit 13 compares the Criticality with the level of security importance established by domestic businesses (step S13 in FIG. 4). In other words, it determines whether the assessment is conservative compared to the US standard. If the comparison shows that the security importance in Japan is higher than in the US (step S13 in FIG. 4, Yes), safety is re-evaluated using the processing flow of step S14 shown in FIG. 6. If the security importance in Japan is lower than in the US (step S13 in FIG. 4, No), economic viability is re-evaluated using the processing flow of step S15 shown in FIG. 7.

The analysis section 16 reviews the importance of maintenance based on the results of the evaluation by the safety evaluation section 14 and the economic evaluation section 15. Perform a gap analysis between maintenance methods and maintenance cycles based on the reviewed maintenance importance. It is thought that gaps can be classified into patterns such as the maintenance method/cycle gap analysis table 25 shown in FIG. 8, and depending on the gap pattern, the maintenance method and maintenance cycle of step S17A shown in FIG. Select the redefinition flow.

The redefining unit 17 redefines the maintenance method and maintenance cycle by implementing the processing flow of steps S17A and S17B.

FIG. 5 is a diagram showing an example of a comparison between PMBD maintenance information and domestic plant maintenance information. FIG. 5 shows the processing contents of the comparison unit 12. The Duty Cycle and Service Conditions described in the PM template are divided into High/Low and Severe/Mild expressions, respectively, but the classification is defined in the PM template, and the corresponding information of domestic equipment is With this arrangement, it is possible to select a more appropriate classification for comparison from eight patterns based on Criticality, Duty Cycle, and Service Conditions. Degradation mechanisms correspond to failure modes. The definition of maintenance methods and maintenance cycles is a common concept in Japan and the United States.

Figure 6 is a flowchart showing the safety reassessment process. Figure 6 shows the process of reassessing the importance of equipment by the safety assessment unit 14 with a focus on safety (corresponding to step S14 in Figure 4). The flow diagram shows the procedure for extracting equipment with a higher importance from the viewpoint of safety from equipment with a high level of maintenance importance using PRA (probabilistic risk assessment) or the like. Since the concepts of safety, laws, regulations, and standards differ between Japan and the United States, the safety assessment unit 14 defines safety indicators (step S141) and performs risk assessment taking into account the differences in concepts defined by system function (step S142). The safety assessment unit 14 performs risk assessment on an equipment-by-equipment basis taking into account the risk assessment by system function performed in step S142 (step S143).

In other words, in step S141, the safety assessment unit 14 checks the difference between the domestic safety approach and the US safety approach. Taking into account the impact of this difference on the safety assessment, in step S142, the safety risk is assessed by system function, and the importance of conservation is reassessed.

In this embodiment, PRA (Probabilistic Risk Assessment), PSA (Probabilistic Safety Assessment), and Transient PSA are used as risk assessment techniques to evaluate safety importance. Probabilistic risk assessment refers to assessing the risk of various events that may occur, taking into account the probability of occurrence, such as the frequency of core damage. Probabilistic safety evaluation is the evaluation of safety by considering the probability of occurrence of various events that may occur. Transient PSA in this embodiment refers to performing PSA without limiting assumed transient events to coolant loss accident events. In step S143, a safety risk evaluation is performed for each device, and the maintenance importance level is reviewed for each device, so that maintenance methods and maintenance cycles can be compared.

In this embodiment, risk evaluation for each device is performed by FMEA (Failure Mode Effect Analysis) or SPV (Single Point Vulnerability Model) to evaluate the degree of importance. Failure mode and impact analysis is a method of analyzing the events that cause failures, the location of the failures, their probability of occurrence, and the effects of the failures on the equipment being evaluated. A single-point vulnerability model is a model that evaluates the impact on the reactor core or turbine due to a single failure of the equipment being evaluated.

FIG. 7 is a flowchart showing the process of re-evaluating economic efficiency. FIG. 7 shows a process performed by the economic efficiency evaluation unit 15 to review the importance of the equipment by focusing on economic efficiency (corresponding to step S15 in FIG. 4). The flowchart shows the procedure for extracting equipment with high importance from the viewpoint of economical efficiency using GRA (power generation risk assessment) from equipment with low maintenance importance.

In Japan, the importance of maintenance is rated low, but in the United States, from an economic standpoint, equipment whose loss of functionality greatly contributes to power generation efficiency may be rated as High Criticality and subject to maintenance. This flow is for reviewing the importance of conservation based on differences in economic evaluation.

Since the concept of economic efficiency, laws, and regulations are different between Japan and the United States, the economic efficiency evaluation unit 15 defines safety indicators (step S151) and performs risk assessment taking into account the difference in concept defined in step S151. (Step S152), risk evaluation for each device is performed in consideration of the risk evaluation for each system function performed in Step S152 (Step S153).

That is, in step S151, the difference between the way of thinking regarding economic efficiency in Japan and the way of thinking regarding economic efficiency in the United States is confirmed. Considering the influence of this difference on the evaluation of economic efficiency, in step S152, power generation risk is evaluated for each system function, and the impact of loss of function on power generation efficiency is evaluated. In this embodiment, GRA (power generation risk assessment) is performed as a risk assessment method to evaluate economic importance. Power generation risk assessment is the evaluation of the impact on power generation functions of various events that may occur, taking into consideration the probability of their occurrence. In step S153, a power generation risk evaluation is performed for each device, and maintenance importance is reviewed for each device, so that maintenance methods and maintenance cycles can be compared. In this embodiment, risk evaluation for each device is performed by performing FMEA (Failure Mode Effect Analysis) and SPV (Single Point Vulnerability Model) to evaluate the degree of importance.

Figure 8 shows the causes of gaps in maintenance methods and maintenance cycles according to their patterns. It shows an example of selecting a flow more suitable for the redefinition unit 17 depending on the cause of the gap (maintenance method/cycle gap analysis table 25 (see Figure 1)).

There are four types of patterns for comparing maintenance methods and maintenance cycles: patterns in which both match, patterns in which only one matches, and patterns in which neither matches. Even if comparisons cannot be made due to reasons such as

In this embodiment, there are differences in the causes of gaps when maintenance methods and maintenance cycles can be compared and when they cannot. We believe that higher reliability can be obtained. The maintenance method and maintenance cycle are redefined using the flow selected here. In the case of FIG. 8, step S17A is executed in the case of #1 and #2, and step S17B is executed in the case of #3. Note that step S17A and step S17B are the detailed processing flow of step S17 in FIG.

FIG. 9 is a flowchart showing the maintenance method/cycle re-evaluation process (step S17A). When differences in maintenance methods, maintenance cycles, or both are recognized, this flow is used to redefine the maintenance methods and maintenance cycles.

The redefinition unit 17 determines whether the usage conditions of the equipment for which the maintenance method and maintenance cycle have been compared are the same (step S17A1), and if the usage conditions are different (step S17A1, No), the redefinition unit 17 corrects the difference in usage conditions. (step S17A2), and the process proceeds to step S17A3. On the other hand, if the usage conditions are the same (step S17A1, Yes), the process advances to step S17A3.

In step S17A3, the redefining unit 17 determines whether the deterioration modes evaluated for the devices are the same. If the evaluated degradation modes are different (step S17A3, No), the redefining unit 17 performs re-evaluation using FMEA (step S17A4), and proceeds to step S17A5). On the other hand, if the evaluated degradation modes are the same (step S17A3, Yes), the process advances to step S17A5.

In step S17A5, the redefining unit 17 uses the maintenance method and maintenance period of the PM template as reference values to evaluate the deterioration mechanism and failure probability of the device. Then, the redefining unit 17 determines the deterioration mode to be monitored and measured and its evaluation method (testing, measurement, etc.) and evaluates the remaining life (step S17A6). It is determined whether it is approved (step S17A7).

If the remaining life until the next periodic inspection is recognized (Step S17A7, Yes), the redefining unit 17 instructs to perform inspections at intervals that take into account the uncertainty of the remaining life (Step S17A8). If the remaining life beyond the periodic inspection is not recognized (Step S17A7, No), a command is given to the unrecognized equipment to carry out parts replacement or repair as usual as a countermeasure (Step S17A9), and the series of processing is completed. do.

To explain further, in step S17A1, it is determined whether the operating conditions of the devices compared in step S12 in FIG. 4, Duty Cycle and Service Conditions, are the same. If they are different, a correction is made for the difference in the operating conditions in step S17A2. In principle, the correction is made by selecting conservative conditions from the PM template.

In step S17A3, it is determined whether the deterioration modes of the equipment components, which are factors that determine the maintenance method and the maintenance cycle, are the same. If they are different, the FMEA is re-evaluated, taking into consideration the possibility that there may be omissions in the deterioration mode. By performing Steps S17A1 to S17A4, when reviewing the maintenance method and maintenance cycle of domestic maintenance target equipment, it is possible to perform evaluation under the same conditions as the equipment described in the PM template.

Step S17A5 evaluates the deterioration mechanism and failure probability using the maintenance method and maintenance cycle of the PM template as reference values. In step S17A6, a deterioration mode to be monitored or evaluated and its evaluation method (test, measurement, etc.) are determined based on the evaluated deterioration mechanism and failure probability, and the remaining life is evaluated. From this information, the most effective maintenance method and maintenance cycle can be determined for each device. During evaluation, the reference value is considered, for example, as an upper limit value, and by providing an evaluation result that does not exceed this value, it can be treated as a valid evaluation result for the maintenance importance level reviewed on a device-by-device basis.

In step S17A7, reliable evidence (accumulation and evaluation of actual data, etc.) is established for the remaining life evaluated in step S17A6, and once it is approved by the domestic nuclear regulatory agency, the equipment maintenance methods and maintenance cycles are redefined.

For example, by digitizing and quantifying the deterioration status of equipment during periodic inspections or during operation (vibration, sound, temperature, images, etc.) as performance data, we can improve its explainability as evidence. improves.

If approved, a maintenance plan will be created using redefined maintenance methods and maintenance intervals, conservatively taking into account the uncertainty of remaining service life. For those that are not recognized, maintenance activities are continued based on the conventional maintenance plan, and the remaining life evaluated in step S17A6 is set as a target value and reliability evidence is accumulated.

FIG. 10 is a flowchart showing the maintenance method/cycle re-evaluation process (step S17B). When it is difficult to compare differences in maintenance methods and maintenance cycles, this flow is used to redefine maintenance methods and maintenance cycles.

The redefining unit 17 determines whether the classification of the PM task is RTF in the PM template (step S17B1), and if different (step S17B1, No), re-evaluates safety and economy (step S17B2), As a result of the re-evaluation, it is determined whether it is possible to consider performing RTF in Japan (step S17B3). On the other hand, if the classification of the PM task in the PM template is RTF (step S17B1, Yes), the process advances to step S17B5.

In step S17B3, if it cannot be determined whether RTF can be considered (step S17B3, No), the process moves to step S17A by referring to conservative data in the PM template (step S17B4); on the other hand, it can be determined whether RTF can be considered. If so (step S17B3, Yes), the process advances to step S17B5.

In step S17B5, the redefining unit 17 performs FMEA of the device whose PM task is RTF in the PM template, determines the deterioration mode to be monitored and measured and its evaluation method (test, measurement, etc.), and determines the remaining lifespan. is evaluated (step S17B6), and it is determined whether this remaining life is acceptable until the next periodic inspection or later (step S17B7).

In step S17B7, if the remaining life until the next regular inspection is not recognized (step S17B7, No), the redefinition unit 17 instructs the equipment not recognized in S17B7 to undergo conventional parts replacement or repair. (Step S17B8). On the other hand, if the remaining life until the next periodic inspection or later is recognized (step S17B7, Yes), the redefining unit 17 proceeds to step S17B9.

In step S17B9, the redefining unit 17 determines whether the conditions that enable RTF are satisfied, and if the conditions are not satisfied (step S17B9, No), the redefinition unit 17 instructs to perform inspections at intervals that take into account the uncertainty of the remaining life ( Step S17B10), if satisfied (Step S17B9, Yes), a command is given to set the device as RTF (Step S17B11), and the series of processing ends.

To explain further, in step S17B1, it is determined whether the PM template to be compared with the device is classified as RTF. If it is not RTF, the safety evaluation (step S14) and economic efficiency evaluation (step S15) performed in FIGS. 6 and 7 are carried out again. At this time, a possible pattern is a case in which only the domestic maintenance method performs RTF, etc., and the maintenance tasks are defined in the US PM template. In this case, since there is a large difference in the importance of maintenance with the United States, safety evaluation and economic evaluation are performed in step S17B2 to review the importance of maintenance in Japan again.

As a result of this evaluation, the maintenance importance level is significantly revised and if it is determined that the RTF response is not appropriate, the process proceeds from step S17B2 to step S17B4, and from the new maintenance importance level, eight patterns based on Criticality, Duty Cycle, and Service Conditions are selected. Select a classification that is more appropriate for comparison, or select a conservative classification and refer to the data for comparison. Thereafter, the process moves to step S17A, and then to step S17A3 to continue evaluation.

If the classification in the PM template is RTF, consider whether to classify the device as RTF, review the maintenance method and maintenance cycle, or perform maintenance tasks as usual.

In step S17B5, FMEA of the device is performed. Based on this analysis result, in step S17B6, the deterioration mode to be monitored or evaluated and its evaluation method (test, measurement, etc.) are determined, and the remaining life is evaluated. Here, for example, by converting test and measurement values (vibration, sound, temperature, images, etc.) into digital and quantitative data, the explainability of evidence can be improved.

At this time, since there is no upper limit set by the PM template, in step S17B7, reliable evidence regarding the remaining life is built, approved by the domestic nuclear regulatory agency, and the equipment maintenance method and maintenance cycle are redefined. Decide if it is possible. For those that are not recognized, maintenance activities are continued based on the conventional maintenance plan, and the remaining life evaluated in step S17B6 is set as a target value and reliability evidence is accumulated. It is determined in step S17B9 whether the recognized device is capable of performing RTF. When the failure of the equipment in question is approved to be handled by domestic RTF, it will be removed from the list of equipment subject to maintenance. If not approved, a maintenance plan is created using the redefined maintenance method and maintenance cycle, conservatively considering the uncertainty of the remaining life recognized in step S17B7.

As explained above, for nuclear power generation equipment, etc., maintenance with higher reliability is required based on risks and equipment deterioration. As a gap analysis, it is known to refer to good practices of domestic and foreign power plants.

In this embodiment, the comparison will be particularly made with the US Preventive Maintenance Basis Database (PMBD). When comparing Japan and the United States, there are differences in how they think about safety and economy, and there is an issue that needs to be taken into account. ) and Failure Mode.

In addition, in this embodiment, in comparing overseas maintenance examples and domestic maintenance activities, PMBD is used to provide information on the current maintenance of equipment subject to maintenance at domestic nuclear power plants (importance classification, equipment usage frequency, Equipment usage conditions, maintenance methods, maintenance cycles, deterioration mechanisms, etc.) and maintenance information organized in EPRI's PMBD (Criticality, Duty Cycle, Service Conditions, Task (maintenance method), Baseline (maintenance cycle), Failure Mode) (failure mode))) and compare it for each item.

Furthermore, in this embodiment, in order to review the maintenance method and maintenance cycle, the maintenance importance level is reviewed in the evaluation flow to be performed, and the maintenance method and maintenance cycle are reevaluated based on the results. Here, we focus on the level of importance and evaluate the level of maintenance importance of equipment to be maintained in Japan from the perspectives of safety and economics, such as PRA (probabilistic risk assessment), PSA (probabilistic safety assessment), transient PSA, and GRA (power generation risk). review), FMEA (Failure Mode and Effect Analysis), and SPV (Single Point Vulnerability Model).

According to the present embodiment, a maintenance support method for supporting a maintenance plan for equipment to be maintained at a nuclear power plant includes a first step of extracting current maintenance items for the equipment to be maintained as first information (for example, 2 step S1), items including Criticality, Duty Cycle, and Service Conditions organized in PMBD (Preventive Maintenance Basis Database) of EPRI (Electric Power Research Institute) are extracted for the equipment to be maintained and used as second information. and a comparison step (for example, step S2 in FIG. 2) in which the second information and the first information are compared item by item.

The items to be compared in the first step are importance classification, equipment usage frequency, equipment usage conditions, maintenance method, maintenance cycle, and deterioration mechanism, and in the second step, Criticality, Duty Cycle, Service Conditions. , Task, Baseline, and Failure Modes.

In addition, the maintenance support method further includes a third step (for example, in FIG. Step S3). In the third step, PRA (Probabilistic Risk Assessment), PSA (Probabilistic Safety Assessment), Transient PSA, GRA (Generation Risk Assessment), FMEA (Failure Mode and Effects Analysis), and SPV (Single Point Vulnerability Model) are The maintenance importance classification of equipment to be maintained can be reviewed.

The maintenance support method further includes a fourth step (for example, the step in FIG. S4), and a fifth step (for example, step S5 in FIG. 2) of redefining the maintenance method and maintenance cycle of the equipment to be maintained based on the re-evaluation result of the fourth step.

The maintenance support device 100 of this embodiment extracts current maintenance items for equipment to be maintained at a nuclear power plant as first information, and uses PMBD (Preventive Maintenance Basis) of EPRI (Electric Power Research Institute) for equipment to be maintained. A comparison information extraction unit 11 extracts items including Criticality, Duty Cycle, and Service Conditions organized in the Database) and uses them as second information, and a comparison unit 12 compares the second information and first information item by item. and an evaluation unit (e.g., safety evaluation unit 14, economic evaluation unit 15) that reviews the maintenance importance classification of the equipment to be maintained from the aspects of safety evaluation and economic evaluation based on the importance classification of Criticality of the second information. ), an analysis unit 16 that re-evaluates the maintenance method and maintenance cycle of the first information according to the pattern of differences between the maintenance method and maintenance cycle of the first information and the second information, and an analysis unit 16 that re-evaluates the maintenance method and maintenance cycle of the first information, based on the re-evaluation results of the analysis unit 16. It also includes a redefining unit 17 that redefines the maintenance method and maintenance cycle of the equipment to be maintained. According to the maintenance support device 100, highly reliable and efficient maintenance activities can be performed for equipment to be maintained at a nuclear power plant.

Note that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the embodiments described above are described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations. Further, each of the above-mentioned configurations, functions, processing units, processing means, etc. may be partially or entirely realized in hardware by designing, for example, an integrated circuit. Furthermore, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs, tables, files, etc. that implement each function can be stored in a memory, a recording device such as a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

10 Processing unit 11 Comparison information extraction unit 12 Comparison unit 13 Importance determination unit 14 Safety evaluation unit (evaluation unit)
15 Economic Evaluation Department (Evaluation Department)
16 Analysis section 17 Redefinition section 20 Storage section 21 PMBD output information 22 Domestic plant information 23 Extraction table 24 Comparison table 25 Maintenance method/cycle gap analysis table 30 Input section 40 Output section 50 Communication section 100 Maintenance support device 200 PMBD
210,220,230 DB
EPRI Electric Power Research Institute
FMEA Potential Failure Mode and Effects Analysis
GRA Generation Risk Assessment
PMBD Preventive Maintenance Basis Database
PRA Probabilistic Risk Assessment
PSA Probabilistic Safety Assessment
RTF Run to Failure
SPV Single Point Vulnerability

Claims (6)

A maintenance support method for a maintenance support device that supports a maintenance plan for equipment to be maintained at a nuclear power plant, the method comprising:
The processing unit of the maintenance support device includes:
a first step of extracting items including current maintenance items such as importance classification, frequency of use of the device, and conditions of use of the device for the equipment to be maintained as first information;
a second step of extracting items including Criticality, Duty Cycle, and Service Conditions organized in PMBD (Preventive Maintenance Basis Database) of EPRI (Electric Power Research Institute) with respect to the equipment to be maintained as second information;
a comparison step of comparing the second information and the first information item by item ;
Output the comparison results in the comparison step
A conservation support method characterized by: The above items are
In the first step, the importance classification, the frequency of use of the equipment, the usage conditions of the equipment, the maintenance method, the maintenance cycle, the deterioration mechanism,
The maintenance support method according to claim 1, wherein the second step includes Criticality, Duty Cycle, Service Conditions, Task, Baseline, and Failure Modes. The equipment to be maintained includes equipment with a high maintenance importance and equipment with a lower maintenance importance than the equipment with a high maintenance importance,
The maintenance support method further includes:
The processing unit determines the maintenance importance classification of the equipment to be maintained in the first information based on the importance classification of the Criticality of the second information , from the equipment with the highest maintenance importance to the system function from the viewpoint of safety. A separate risk assessment and a safety assessment, which is a risk assessment for each device, are performed, and an economic evaluation is performed, starting from the equipment with the lowest maintenance importance, and a risk assessment for each system function and a risk assessment for each device are performed from an economic perspective. The maintenance support method according to claim 1, further comprising a third step of reviewing the maintenance importance level from the viewpoint of the safety evaluation and the economic evaluation . In the third step,
The processing unit,
PRA (probabilistic risk assessment) , which evaluates risks by considering the probability of occurrence of injury frequency for various events that may occur ;
PSA (probabilistic safety assessment) , which evaluates safety by considering the probability of occurrence of various events that may occur ;
Transient PSA when performing the PSA, in which the assumed transient event is not limited to a loss of coolant accident event ;
GRA (power generation risk assessment) , which evaluates the impact on power generation functions by considering the probability of occurrence of various events that may occur ;
FMEA (failure mode and effect analysis) , which analyzes the events that cause failures of the equipment being evaluated, their failure locations, probability of occurrence, and the effects of failures ;
SPV (Single Point Vulnerability Model) , which evaluates the impact on the reactor core or turbine due to a single failure of the equipment being evaluated ;
4. The maintenance support method according to claim 3, wherein the maintenance importance classification of the equipment to be maintained is reviewed using the following. The maintenance support method further includes:
The processing unit,
Determine the remaining life of the equipment to be maintained according to a pattern of differences between the maintenance method and maintenance cycle of the first information and the second information, and determine the maintenance method and maintenance cycle of the first information based on the remaining life. The fourth step is to reevaluate.
A fifth step of redefining a maintenance method and a maintenance cycle for the equipment to be maintained based on the maintenance importance level reviewed in the third step and the re-evaluation result in the fourth step. The maintenance support method according to claim 3. Regarding equipment to be maintained at nuclear power plants , items including current maintenance items such as importance classification, equipment usage frequency, and equipment usage conditions are extracted as first information, and regarding the equipment to be maintained, EPRI (Electric Power a comparative information extraction unit that extracts items including Criticality, Duty Cycle, and Service Conditions organized in PMBD (Preventive Maintenance Basis Database) of the Research Institute) and uses them as second information;
a comparison unit that compares the second information and the first information item by item;
The equipment to be maintained includes equipment with a high maintenance importance and equipment with a lower maintenance importance than the equipment with a high maintenance importance, and based on the importance classification of the Criticality of the second information, Based on the maintenance importance classification of the above-mentioned equipment to be maintained in the 1 information , a risk assessment for each system function and a safety assessment, which is a risk assessment for each device, are performed from the viewpoint of safety , starting from the equipment with the highest maintenance importance. Evaluate the importance of maintenance from the perspective of the safety evaluation and the economic evaluation by performing an economic evaluation, which is a risk evaluation for each system function and a risk evaluation for each device, from the viewpoint of economic efficiency, starting with the equipment with a low degree of safety. Department and
Determine the remaining life of the equipment to be maintained according to a pattern of differences between the maintenance method and maintenance cycle of the first information and the second information, and determine the maintenance method and maintenance cycle of the first information based on the remaining life. The analysis department re-evaluates,
A maintenance support comprising: a redefining unit that redefines a maintenance method and a maintenance cycle for the equipment to be maintained, based on the maintenance importance level reviewed by the evaluation unit and the re-evaluation result of the analysis unit. Device.

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