System for optimizing the repair plan of nuclear power plants, method for optimizing the repair plan of nuclear power plants, and program for optimizing the repair plan of nuclear power plants.

Abstract

Evaluate the increased radiation exposure resulting from the extension of the inspection cycle for in-reactor equipment, and adjust the inspection cycle accordingly. [Solution] The plant repair plan optimization system S comprises: a detection unit that detects environmental information of a nuclear power plant in operation; a soundness monitoring unit that constantly monitors the soundness of equipment based on the environmental information of the nuclear power plant and the importance information of the equipment that constitutes it; an exposure dose evaluation unit that evaluates the exposure dose received by workers of the nuclear power plant based on the monitoring results of the nuclear power plant by the soundness monitoring unit; a preventive maintenance unit that issues preventive maintenance instructions for equipment based on the soundness evaluation results of the equipment in operation and the exposure dose evaluation results of workers; and a life cycle management unit that creates a repair plan for the nuclear power plant based on preventive maintenance instructions for equipment corrosion, the soundness evaluation results of the equipment, and the exposure dose evaluation results of workers.

Description

Technical Field

[0001] The present invention relates to a system for optimizing a maintenance plan of a nuclear power plant, a method for optimizing a maintenance plan of a nuclear power plant, and a program for optimizing a maintenance plan of a nuclear power plant.

Background Art

[0002] There is a need for a method to optimize the maintenance plan for nuclear facilities such as nuclear power plants, Fukushima decommissioning measures, and reprocessing facilities.

[0003] Patent Document 1 describes an invention that improves the reliability of equipment including large structures such as structural materials and weld lines, not only conventional equipment, by simultaneously utilizing inspections during the service period and operating parameters of nuclear facilities.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Currently, the US INPO (Institute of Nuclear Power Operation) and the domestic NRA (Nuclear Regulation Authority) have published reliability evaluation methods for equipment and facilities. In the future, the soundness of materials and large structures that will become important due to high aging is evaluated through inspections and the like conducted during regular inspections. Methods for continuously and constantly monitoring the soundness of these materials and large structures that will become important due to high aging are being studied.

[0006] Furthermore, Patent Document 1 describes an invention of a basic process for continuously monitoring and evaluating the deterioration state of large structures and materials in response to the aging of power plants. However, in addition to aging, power plants are also required to operate for longer periods and extend inspection cycles. Optimizing maintenance cycles requires not only evaluating water quality, which mitigates material degradation, but also assessing the increased radiation exposure that comes with extending inspection cycles.

[0007] Therefore, the present invention aims to optimize the repair plan for a nuclear power plant by taking into consideration the evaluation of the radiation exposure dose of workers working at the plant. [Means for solving the problem]

[0008] To solve the aforementioned problems, the nuclear power plant repair plan optimization system of the present invention is characterized by comprising: a detection unit that detects environmental information of a nuclear power plant in operation; a soundness monitoring unit that constantly monitors the soundness of the equipment constituting the nuclear power plant based on the environmental information of the nuclear power plant in operation and the importance information of the equipment constituting the nuclear power plant; an exposure dose evaluation unit that evaluates the exposure dose received by workers of the nuclear power plant based on the monitoring results of the nuclear power plant by the soundness monitoring unit; a preventive maintenance unit that instructs preventive maintenance of the equipment based on the soundness evaluation results of the equipment in operation by the soundness monitoring unit and the exposure dose evaluation results of workers by the exposure dose evaluation unit; and a life cycle management unit that creates a repair plan for the nuclear power plant based on the preventive maintenance instructions for corrosion of the equipment by the preventive maintenance unit, the soundness evaluation results of the equipment by the soundness monitoring unit, and the exposure dose evaluation results of workers by the exposure dose evaluation unit.

[0009] The present invention provides a method for optimizing the repair plan for a nuclear power plant, characterized by the following steps: a detection unit detects environmental information of a nuclear power plant in operation; a soundness monitoring unit continuously monitors the soundness of the equipment constituting the nuclear power plant based on the environmental information of the nuclear power plant in operation and the importance of the equipment constituting the nuclear power plant; an exposure dose evaluation unit evaluates the exposure dose of workers based on the monitoring results by the soundness monitoring unit; a preventive maintenance unit instructs preventive maintenance of the equipment based on the soundness evaluation results of the equipment in operation by the soundness monitoring unit and the exposure dose evaluation results of workers by the exposure dose evaluation unit; a life cycle management unit creates a repair plan for the nuclear power plant based on the preventive maintenance instruction for corrosion of the equipment by the preventive maintenance unit and the soundness evaluation results of the equipment by the soundness monitoring unit.

[0010] The present invention provides a program for optimizing repair plans for nuclear power plants, which enables a computer to perform the following steps: a procedure for detecting environmental information of a nuclear power plant in operation; a procedure for continuously monitoring the integrity of the equipment constituting the nuclear power plant based on the environmental information of the nuclear power plant in operation and the importance information of the equipment constituting the nuclear power plant; a procedure for evaluating the radiation exposure dose of workers based on the monitoring results of the integrity of the equipment constituting the nuclear power plant; a procedure for issuing preventive maintenance orders for the equipment based on the results of the integrity evaluation of the equipment in operation and the results of the radiation exposure dose evaluation of the workers; a procedure for creating a repair plan for the nuclear power plant based on preventive maintenance orders for corrosion of the equipment, the results of the integrity evaluation of the equipment, and the results of the radiation exposure dose evaluation of the workers at the nuclear power plant. Other means will be described within the descriptions of embodiments for carrying out the invention. [Effects of the Invention]

[0011] According to the present invention, the repair plan for a nuclear power plant can be optimized by taking into consideration the evaluation of the radiation dose received by workers working at the nuclear power plant. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the reliability and lifecycle management of equipment in a nuclear power plant according to this embodiment. [Figure 2] This is a diagram illustrating the configuration of a system for optimizing repair plans for nuclear power plants. [Figure 3] This is a diagram illustrating the configuration of a nuclear power plant. [Figure 4] This is a hardware configuration diagram for the server. [Figure 5] This is a hardware configuration diagram of the terminal. [Figure 6] This is a functional block diagram of a system for optimizing repair plans for nuclear power plants. [Figure 7] This diagram shows the reliability and lifecycle management of welds in nuclear power plants. [Figure 8] This diagram shows the reliability and lifecycle management of piping in nuclear power plants. [Figure 9] This is a flowchart showing the process for periodic inspections in the comparative example. [Figure 10] This figure shows the reliability and lifecycle management of equipment in a comparative example nuclear power plant. [Modes for carrying out the invention]

[0013] Hereafter, embodiments for implementing comparative examples will be described with reference to Figures 9 and 10, and embodiments for implementing the present invention will be described with reference to Figures 1 to 8. In the following description, identical components will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0014] 《Operation of the comparative example》 Figure 9 is a flowchart showing the process for a comparative example's periodic inspection. This periodic inspection is carried out with the nuclear power plant shut down. The inspector starts the inspection during the regular inspection (step S40). In the comparative example, structural materials, weld lines, etc. related to the integrity of the reactor are inspected and evaluated separately. The inspector evaluates the inspection results (step S41) and sets the inspection period (step S42).

[0015] Next, the inspector replaces the equipment / facility (step S43) and reflects it in the large-scale repair plan (step S44). Finally, when the inspector evaluates the plant life (step S45), the process in FIG. 9 ends.

[0016] FIG. 10 is a diagram showing the reliability and life cycle management of the equipment of the comparative example nuclear power plant, and is based on AP-913 (Equipment Reliability Process Description) of the Nuclear Power Generation Operation Association of the United States. AP-913 is a diagram showing the process for managing the reliability of equipment and facilities related to operation in a nuclear power reactor and the life cycle of the plant.

[0017] First, when the management system classifies the importance (step S50), it monitors the performance according to this importance (step S51). Then, the administrator continuously improves the reliability of the equipment according to this importance (step S53). The administrator performs preventive maintenance of the equipment / facility (step S54). The equipment / facility for which preventive maintenance has been performed becomes the object of the performance monitoring process (step S51).

[0018] The administrator takes corrective measures for the equipment / facility based on the monitoring results of the performance (step S52). And the result of the corrective measures is fed back to the performance monitoring process (step S51) and the continuous equipment reliability improvement process (step S53).

[0019] Finally, based on the continuous equipment reliability improvement process (step S53), the corrective measures (step S52), and the performance monitoring process (step S51), the administrator executes life cycle management (step S55).

[0020] Operation and Configuration of This Embodiment In this embodiment, the reliability of the entire nuclear power plant is visualized by introducing the assessment of structural materials and large structures into the conventional AP-913 concept. This then optimizes the repair plan for the nuclear power plant. The structural integrity of materials and large structures such as pressure vessels in the nuclear power plant is assessed by reflecting data on system importance, frequency of use, operating temperature or the operating environment of fluids such as water or steam, and operating corrosion environment data, as well as past data from periodic inspections and standard data.

[0021] This integrity assessment method evaluates the integrity, configuration, and function of the system and equipment based on the types of chemical elements and materials contained in the reactor water during operation, as well as construction data. Here, integrity is assessed using not only data from operation but also inspection results obtained during periodic maintenance.

[0022] The integrity of materials in nuclear power plants, as well as the integrity of large structures such as pressure vessels, is continuously evaluated by taking into account the importance of the system, frequency of use, operating temperature or the operating environment of fluids such as water or steam, and operating corrosion environment data, as well as the number of fuel replacements during periodic inspections, the radioactivity concentration during operation, and the corrosion behavior of the target materials.

[0023] For operation spanning over 40 years, it is possible to continuously monitor the reliability of not only conventional equipment but also large structural components such as structural materials and weld lines. This allows for optimal inspection, equipment replacement, and large-scale repair work, ensuring reliability while optimizing costs.

[0024] Figure 1 shows the reliability and lifecycle management of equipment in a nuclear power plant according to this embodiment. The repair plan optimization system S shown in Figure 2 classifies structures by importance (step S10). The importance of a structure affects the safety system within the reactor, the integrity of the fuel inside the reactor, and the release of radioactive materials outside the system. Factors influencing the importance of a structure include not only those stipulated by law, but also the results of previous inspections, the fluids that come into contact with the structure under operating conditions, and the types and concentrations of chemical substances contained in the reactor water in the reactor pressure vessel during operation.

[0025] The types of structures classified in step S10 include reactor pressure vessels, shrouds, shroud supports, jet pumps, grid plates and other in-reactor structures and equipment related to the insertion of control rods, turbine casings, bearings, condensers, generators and hydrogen supply equipment, heat exchangers of the old condensate system, fuel support plates, and major piping connecting equipment whose safety importance and power generation importance are above a threshold. Nuclear facilities also include fuel fabrication plants, nuclear fuel cycle plants, and radioactive waste disposal sites.

[0026] In step S10B, the repair plan optimization system S obtains the fuel operation plan for the nuclear power plant P from a higher-level functional unit (not shown). The fuel operation plan information includes information on fuel replacement and / or the number of fuel shuffling units. By searching the database based on this information, the system obtains information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0027] In step S11, the repair plan optimization system S monitors the structural integrity. Integrity monitoring involves evaluating the current reliability of the structure based on previous inspection results, the fuel operation plan of the nuclear power plant P, the operating status of the nuclear power plant P, maintenance standards, criteria, and conventional knowledge such as research papers. The repair plan optimization system S continuously monitors the structural integrity of large structures at the nuclear power plant by using information on the structure's configuration, equipment layout, material composition, corrosion environment data, cobalt (Co) concentration, water quality data, operating status, fuel replacement and shuffling unit count, corrosion rate information for stainless steel, carbon steel, and nickel-based alloys, thinning rate information for stainless steel, carbon steel, and nickel-based alloys, corrosion rate information for carbon steel, thinning rate information for carbon steel, and platinum deposition amount. The repair plan optimization system S may further monitor the structural integrity based on periodic inspection information of the nuclear power plant P.

[0028] In step S11B, the repair plan optimization system S evaluates the radiation dose that workers will be exposed to while working at the nuclear power plant P. The repair plan optimization system S evaluates the radiation dose of workers from the information included in the fuel operation plan, such as the number of fuel replacements and / or fuel shuffling units, the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0029] Based on the type of structure classified in step S10, the repair plan optimization system S continuously improves the reliability of the equipment (step S13). Specifically, the repair plan optimization system S performs inspection and mitigation (step S14). In the inspection phase, the repair plan optimization system S selects an inspection frequency and inspection method that minimizes costs while ensuring reliability, taking into account the inspection results, maintenance standards, laws, and periodic inspection procedures. In the mitigation phase, the repair plan optimization system S instructs the worker's terminal 6 to perform stress relief and / or environmental mitigation (step S14). In response, the worker performs stress relief and / or environmental mitigation on the structure.

[0030] The repair plan optimization system S implements countermeasures for operational methods (step S12) based on the results of monitoring the structural integrity and the radiation exposure doses of workers at the nuclear power plant P. Countermeasures for operational methods here refer to improvements in the operation and operational methods of the nuclear power plant P, taking into account the radiation exposure doses of workers, strengthening sampling, and changing the operation of mitigation technologies.

[0031] In step S15, the repair plan optimization system S optimizes the repair plan based on the results of the soundness monitoring, the results of the countermeasures for the operational methods, the results of the continuous improvement of the reliability of the structure, and the evaluation results of the radiation exposure of workers. Here, the optimization of the repair plan is life cycle management, which requires large-scale construction and inspections. Therefore, the repair plan optimization system S takes into account the long-term periodic inspection process and optimizes the plan to ensure the reliability of the structure while considering the radiation exposure of workers, so that the radiation dose is below the level at which workers can work, and so that the sum of the maintenance cost of the structure and the work cost of the workers is minimized.

[0032] Extending the replacement cycle of components that make up a structure reduces the maintenance cost of the structure. However, using components for extended periods reduces the amount of time a single worker can work on the structure, and multiple workers may be required for the same task. This increases the labor cost of the workers. Furthermore, if the radiation dose to which workers can work on the structure exceeds a certain level, workers will be unable to work, and expensive equipment such as robots will need to be deployed. Therefore, it is necessary to determine the maintenance and inspection cycles, such as component replacement, so that the radiation dose to which workers can work remains below a certain level, and the sum of the structure's maintenance cost and the labor cost of the workers is minimized.

[0033] Figure 2 is a diagram showing the configuration of the repair plan optimization system S for a nuclear power plant P. The repair plan optimization system S consists of a server 5, an environmental information sensor 58, a corrosion potential sensor 4, a dose sensor 59, and multiple terminals 6.

[0034] Server 5 is a computer that embodies the functional parts of the repair plan optimization system S. Terminal 6 is an input / output device for accessing Server 5. The operating environment information sensor 58 is a sensor that detects the operating environment of the equipment constituting the nuclear power plant P. The corrosion potential sensor 4 is a sensor that detects corrosion environment information of the equipment constituting the nuclear power plant P. The dose sensor 59 is a sensor that measures the radiation dose at each site.

[0035] Figure 3 is a diagram showing the configuration of a nuclear power plant P. Nuclear power plant P is a boiling water type nuclear power plant and is equipped with a reactor pressure vessel 20, a reactor containment vessel 21, a turbine 22, recirculation system piping 23, a reactor purification system 24, and multiple corrosion potential measuring devices. The reactor pressure vessel 20, installed inside the reactor containment vessel 21, houses a reactor core 25 loaded with multiple fuel assemblies (not shown).

[0036] Each of the two recirculation systems has recirculation piping 23 and a recirculation pump 26. Main steam piping 27, connected to the reactor pressure vessel 20, is connected to the turbine 22. A condenser 28, connected to the turbine 22, is connected to the reactor pressure vessel 20 via feedwater piping 30 after condensate piping 29. Off-gas piping 31 is connected to the condenser 28. Off-gas piping 31 is connected to condensate piping 29, and a dose rate monitor 32 is installed near the main steam piping 27.

[0037] The reactor purification system 24 has piping connected to the recirculation system piping 23 and drain piping 33 connected to the bottom of the reactor pressure vessel 20, and includes a purification device (not shown) within the system. The reactor purification system 24 is connected to the feedwater piping 30.

[0038] Water quality measuring device 34a is connected to drain pipe 33 by sampling pipe 35a, and water quality measuring device 34b is installed in reactor purification system 24 by sampling pipe 35b. Water quality measuring device 34c is connected to feedwater pipe 30 by sampling pipe 35c, and water quality measuring device 34d is installed in main steam pipe 27 by sampling pipe 35d.

[0039] The corrosion potential sensor 4 is installed at the relevant location in the boiling water reactor nuclear power plant using the local power area monitor outer tube 1. The corrosion potential sensor 4 is installed at a corresponding position within the lower plenum 36 at the bottom of the reactor pressure vessel 20 in order to measure the water quality within the lower plenum 36. In this case, the corrosion potential sensor 4 is installed at the height near the lower end of the pressure vessel to measure the corrosion potential near the lower end of the pressure vessel 8, and a corrosion potential measurement window is opened at that height (not shown).

[0040] Corrosion potential measurement using a local output region monitor does not provide a direct correspondence with the sampled water quality, such as oxygen and hydrogen peroxide. However, in the case of measuring the corrosion potential near the lower end of the pressure vessel 8 as described above, furnace water can be collected using the sampling pipe 35a and measured with the water quality measuring device 34a.

[0041] By measuring the corrosion potential in this way, the amount of hydrogen injected into the feedwater from the sampling pipe, which is a hydrogen injection device, is adjusted so that the corrosion potential in the lower plenum 36 drops to a target value. Any excess hydrogen injected into the reactor water in the reactor pressure vessel 20 is exhausted to the off-gas system piping 31 via the main steam piping 27, turbine 22, and condenser 28. The excess hydrogen exhausted to the off-gas system piping 31 is combined with oxygen and processed in a recombiner (not shown) provided in the off-gas system piping 31.

[0042] The hydrogen concentration of the feedwater is obtained by measuring the feedwater sampled in the sampling pipe 35c using the water quality measuring device 34c. Furthermore, the dose rate in the main steam pipe 27 during hydrogen injection is monitored by the dose rate monitor 32.

[0043] This method allows multiple corrosion potential sensors 4 to be placed on the local output area monitor outer tube 1. By installing them at multiple locations in a boiling water reactor (BCU) nuclear power plant, it is possible to three-dimensionally map the corrosion environment in which stress corrosion cracking (SCC) occurs in the structural members of the BCU within the lower plenum 36. As a result, it is possible to provide maintenance measures to ensure the long-term safety, soundness, and reliability of the nuclear power plant.

[0044] Figure 4 is a hardware configuration diagram of server 5. Server 5 is, for example, a computer installed in a data center. Server 5 consists of a CPU (Central Processing Unit) 51, a storage unit 57, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, an operation unit 54, a display unit 55, and a communication unit 56.

[0045] The CPU 51 is a central processing unit that executes the program 571 stored in the memory unit 57. The program 571 is executed by the CPU 51 and performs the processes shown in Figure 1. The CPU 61 implements each of the functional units shown in Figure 6 by executing program 571. The processes performed by the CPU 61 will be described later using Figures 1, 7, and 8.

[0046] The memory unit 57 is a large-capacity storage device, and is composed of, for example, a hard disk drive or flash memory.

[0047] RAM53 is volatile memory and functions as a work area that temporarily stores various programs, input data, output data, and parameters that can be executed by the CPU51. ROM52 is non-volatile memory and stores things like the BIOS (Basic I / O System).

[0048] The control unit 54 is comprised of a keyboard equipped with cursor keys, number input keys, and various function keys, and a pointing device such as a mouse. The control unit 54 detects key press signals from the keyboard and operation signals from the mouse. The CPU 51 performs various processes based on the operation signals from the control unit 54.

[0049] The display unit 55 is configured to include a monitor display such as an LCD (Liquid Crystal Display). The display unit 55 displays various screens based on display signals input from the CPU 51. Furthermore, the display unit 55 and the operation unit 54 can also employ touch panel displays.

[0050] Figure 5 is a hardware configuration diagram of terminal 6. Terminal 6 is, for example, a tablet terminal owned by each worker. Terminal 6 is composed of a CPU 61, a memory unit 67, a ROM 62, a RAM 63, a touch panel display 64, and a communication unit 66.

[0051] The CPU 61 is a central processing unit that executes the program 671 stored in the memory unit 67. The program 671 is, for example, a browser, which is executed by the CPU 61 to perform input / output processing with the server 5.

[0052] The memory unit 67 is a large-capacity storage device, and is composed of, for example, a hard disk drive or flash memory.

[0053] RAM63 is volatile memory and functions as a work area that temporarily stores various programs, input data, output data, and parameters that can be executed by the CPU61. ROM62 is non-volatile memory and stores, for example, the BIOS.

[0054] The touch panel display 64 consists of a transparent touch panel superimposed on a display such as an LCD. The touch panel display 64 detects press signals when a touch is pressed on the touch panel. The CPU 61 performs various processes based on the operation signals from the touch panel display 64. The touch panel display 64 then displays various screens based on display signals input from the CPU 61.

[0055] Figure 6 is a functional block diagram of the nuclear power plant repair plan optimization system S. The repair plan optimization system S includes a detection unit 511, a severity classification unit 512, a periodic inspection information reception unit 513, a health monitoring unit 514, a preventive maintenance unit 515, a life cycle management unit 516, a fuel operation planning unit 517, a radiation dose evaluation unit 518, a fuel exchange / shuffling database 519, and a radiation dose database 520. The detection unit 511 detects environmental information of the operating nuclear power plant P. The environmental information detected by the detection unit 511 includes any of the following: the types and concentrations of chemical substances contained in the reactor water of the reactor pressure vessel during operation, the types of materials, and construction data from the time of construction.

[0056] The fuel operation planning unit 517 obtains the fuel operation plan for the nuclear power plant P from a higher-level functional unit (not shown). The fuel operation plan information includes information on the number of fuel replacements and / or fuel shuffling units. The fuel replacement / shuffling database 519 contains the correspondence between the information on the number of fuel replacements and / or fuel shuffling units and information on the corrosion rates of stainless steel, carbon steel, and nickel-based alloys, the thinning rates of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited. The fuel operation planning unit 517 refers to this fuel replacement / shuffling database 519 to obtain the information on the number of fuel replacements and / or fuel shuffling units, the corrosion rates of stainless steel, carbon steel, and nickel-based alloys, the thinning rates of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0057] The integrity monitoring unit 514 continuously monitors the integrity of the equipment constituting the nuclear power plant P based on environmental information of the operating nuclear power plant P, importance information of the equipment constituting the nuclear power plant P, and the fuel operation plan of the nuclear power plant P. The integrity monitoring unit 514 may, but is not limited to, continuously monitor the integrity of the equipment constituting the nuclear power plant P based on periodic inspection information and / or standard information of the nuclear power plant P.

[0058] The radiation dose evaluation unit 518 evaluates the radiation doses of workers working at the nuclear power plant P. The radiation dose evaluation unit 518 refers to the radiation dose database 520 and evaluates the radiation doses of workers from information obtained from health monitoring information and fuel operation plan information, including information on the number of fuel replacements and / or fuel shuffling units, information on the thinning rate of stainless steel, carbon steel, and nickel-based alloys, information on the corrosion rate of carbon steel, information on the thinning rate of carbon steel, and information on the amount of platinum deposited. The radiation dose database 520 stores the relationship between the information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, information on the thinning rate of stainless steel, carbon steel, and nickel-based alloys, information on the corrosion rate of carbon steel, information on the thinning rate of carbon steel, and information on the amount of platinum deposited, and the radiation doses of workers.

[0059] The Preventive Maintenance Unit 515 issues instructions for preventive maintenance for each piece of equipment based on the results of the integrity assessment of the equipment constituting the operating nuclear power plant P conducted by the Integrity Monitoring Unit 514. The Lifecycle Management Department 516 creates a repair plan for the nuclear power plant P based on preventive maintenance instructions for equipment corrosion issued by the Preventive Maintenance Department 515 and the results of the equipment integrity assessment conducted by the Integrity Monitoring Department 514.

[0060] The periodic inspection information receiving unit 513 receives input of periodic inspection information and / or standard information for the nuclear power plant P. Note that this periodic inspection information receiving unit 513 is not an essential component.

[0061] The importance classification unit 512 classifies the importance of the equipment constituting the nuclear power plant P. Note that this importance classification unit 512 is not an essential component, and the importance of the equipment may be classified manually.

[0062] Figure 7 shows the reliability and lifecycle management of welds in a nuclear power plant. Weld lines can be found in various structures and piping joints, including those in the reactor pressure vessel, shroud, shroud support, jet pumps, grid plates, and other in-reactor structures and equipment related to the insertion of control rods, as well as in the turbine casing, bearings, condenser, generator and hydrogen supply equipment, and heat exchangers of the old condenser system.

[0063] The Repair Plan Optimization System S classifies weld lines by importance (Step S20). The importance of a weld line is determined by factors that affect long-term integrity assessment, such as whether it affects the safety system inside the reactor, the integrity of the fuel inside the reactor, whether it affects the release of radioactive materials outside the system, whether it is mandated by law, conventional knowledge, welding method, type of welding, metal used for welding, post-weld processes such as polishing, contacting fluids, and the types and concentrations of chemical substances contained in the reactor water in the reactor pressure vessel during operation.

[0064] In step S20B, the repair plan optimization system S obtains the fuel operation plan for the nuclear power plant P from a higher-level functional unit (not shown). The fuel operation plan information includes information on fuel replacement and / or the number of fuel shuffling units. By searching the database based on this information, the system obtains information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0065] In step S21, the repair plan optimization system S monitors the integrity of welds. Specifically, monitoring the integrity of welds involves evaluating the current reliability of welds based on previous inspection results and conventional knowledge such as the operational status of the nuclear power plant P, maintenance standards, criteria, and published papers. The repair plan optimization system S continuously monitors the integrity of large structures at the nuclear power plant by using information on the structure's configuration during operation, equipment layout, material composition, corrosion environment data, cobalt (Co) concentration, water quality data, operating status, fuel replacement and shuffling number information, corrosion rate information for stainless steel, carbon steel, and nickel-based alloys, thinning rate information for stainless steel, carbon steel, and nickel-based alloys, corrosion rate of carbon steel, thinning rate of carbon steel, and platinum deposition amount. The repair plan optimization system S may further monitor the integrity of structures based on periodic inspection information of the nuclear power plant P.

[0066] In step S21B, the repair plan optimization system S evaluates the radiation dose to be received by workers working at the nuclear power plant P. The repair plan optimization system S evaluates the radiation dose to be received by workers from the information on the number of fuel replacements and / or fuel shuffling units included in the fuel operation plan, the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0067] Based on the type of weld line classified in step S20, the maintenance plan optimization system S continuously improves the reliability of the equipment (step S23). Specifically, the maintenance plan optimization system S performs inspection and mitigation (step S24). In the inspection phase, the maintenance plan optimization system S selects an inspection frequency and inspection method that minimizes costs while ensuring reliability, taking into account the inspection results, maintenance standards, laws, and periodic inspection procedures. Then, in the mitigation phase, the maintenance plan optimization system S instructs stress mitigation and / or environmental mitigation (step S24). In response, the workers perform stress mitigation and / or environmental mitigation on the weld line.

[0068] The repair plan optimization system S implements countermeasures for operational methods (step S22) based on the monitoring results of the integrity of weld lines and the radiation exposure doses of workers working at the nuclear power plant P. Countermeasures for operational methods here refer to improvements in the operation and operational methods of the nuclear power plant P, taking into account the radiation exposure doses of workers, strengthening sampling, and changing the operation of mitigation technologies.

[0069] In step S25, the repair plan optimization system S optimizes the repair plan based on the results of health monitoring, the results of countermeasures for operational methods, the results of continuous equipment reliability improvement, and the evaluation results of worker exposure doses. Here, the optimization of the repair plan is life cycle management, which requires large-scale construction and inspections. Therefore, the repair plan optimization system S takes into account the long-term periodic inspection process, ensuring the reliability of equipment and machinery, while also considering worker exposure doses, so that the dose is below the level at which workers can work, and so that the sum of structural maintenance costs and worker work costs is minimized.

[0070] Extending the replacement cycle of components that make up a structure reduces the maintenance cost of the structure. However, using components for extended periods reduces the amount of time a single worker can work on the structure, and may require multiple workers for the same task. This increases the labor cost of the workers. Furthermore, if the radiation dose to which workers can work on the structure exceeds a certain level, workers will be unable to work, and expensive equipment such as robots will need to be deployed. Therefore, it is necessary to determine the component replacement cycle so that the radiation dose to which workers can work remains below a certain level, and so that the sum of the structure's maintenance cost and the labor cost of the workers is minimized.

[0071] Figure 8 shows the reliability and lifecycle management of piping in a nuclear power plant. Piping types include the type of fluid flowing through the pipe, the material, and whether it is installed on the reactor side, turbine side, or RAID equipment. The type of liquid refers to whether it contains water, steam, or chemical substances.

[0072] The Repair Plan Optimization System S classifies piping by importance (Step S30). The importance classification of piping is determined by factors such as the safety system within the reactor, the integrity of the fuel within the reactor, whether or not it affects the release of radioactive materials outside the system, whether or not it is determined by laws, company regulations, standards, and environmental factors such as the concentration of radioactive materials and the type and concentration of chemical substances.

[0073] In step S30B, the repair plan optimization system S obtains the fuel operation plan for the nuclear power plant P from a higher-level functional unit (not shown). The fuel operation plan information includes information on fuel replacement and / or the number of fuel shuffling units. By searching the database based on this information, the system obtains information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0074] In step S31, the repair plan optimization system S monitors the integrity of the piping. Specifically, piping integrity monitoring evaluates the current reliability of the piping based on previous inspection results, the plant's operating status, maintenance standards, criteria, and conventional knowledge such as published papers. The repair plan optimization system S continuously monitors the reliability of the nuclear power plant's piping by using information on the structure's configuration during operation, equipment layout, material composition, corrosion environment data, cobalt (Co) concentration, water quality data, operating status, fuel replacement and shuffling count, corrosion rate information for stainless steel, carbon steel, and nickel-based alloys, thinning rate information for stainless steel, carbon steel, and nickel-based alloys, corrosion rate of carbon steel, thinning rate of carbon steel, and platinum deposition amount. The repair plan optimization system S may further monitor the reliability of the piping based on periodic inspection information of the nuclear power plant P.

[0075] In step S31B, the repair plan optimization system S evaluates the radiation dose that workers will be exposed to while working at the nuclear power plant P. The repair plan optimization system S evaluates the radiation dose of workers from the information included in the fuel operation plan, such as the number of fuel replacements and / or fuel shuffling units, the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited.

[0076] Based on the type of weld classified in step S30, the maintenance plan optimization system S continuously improves the reliability of the equipment (step S33). Specifically, the maintenance plan optimization system S performs inspection and mitigation (step S34). In the inspection phase, the maintenance plan optimization system S selects an inspection frequency and inspection method that minimizes costs while ensuring reliability, taking into account inspection results, maintenance standards, laws, and periodic inspection procedures. Then, in the mitigation phase, the maintenance plan optimization system S performs stress relief and / or environmental relief.

[0077] The repair plan optimization system S implements countermeasures for operational methods (step S32) based on the monitoring results of the integrity of weld lines and the radiation exposure doses of workers working at the nuclear power plant P. Countermeasures for operational methods here refer to improvements in the operation and operational methods of the nuclear power plant P, taking into account the radiation exposure doses of workers, strengthening sampling, and changing the operation of mitigation technologies.

[0078] In step S35, the repair plan optimization system S optimizes the repair plan based on the results of health monitoring, the results of countermeasures for operational methods, the results of continuous equipment reliability improvement, and the evaluation results of worker exposure doses. Here, the optimization of the repair plan is life cycle management, which requires large-scale construction and inspections. Therefore, the repair plan optimization system S takes into account the long-term periodic inspection process, ensuring the reliability of the equipment while considering the worker exposure dose, so that the dose is below the level at which workers can work, and so that the sum of the structural maintenance cost and the worker's work cost is minimized.

[0079] By incorporating corrosion environment, material composition, material degradation data, and inspection results—which were previously obtained through in-service inspections—into the equipment reliability standards set by the U.S. Institute of Nuclear Power Operations (INPO), it becomes possible to continuously monitor the degradation status of structures, equipment, and systems. This facilitates continuous monitoring of the integrity of nuclear power plants and the evaluation of the plant lifecycle.

[0080] The configuration and effects of the present invention will be described below.

[0081] [Claim 1] A detection unit (511) that detects environmental information of a nuclear power plant (P) in operation, A soundness monitoring unit (514) continuously monitors the soundness of the equipment constituting the nuclear power plant (P) based on the environmental information of the operating nuclear power plant (P) and the importance information of the equipment constituting the nuclear power plant (P), Based on the monitoring results of the nuclear power plant (P) by the soundness monitoring unit (514), the exposure dose evaluation unit (518) evaluates the exposure dose to which the workers of the nuclear power plant (P) were exposed, Based on the results of the integrity evaluation of the equipment during operation by the integrity monitoring unit (514) and the results of the worker's exposure dose evaluation by the exposure dose evaluation unit (518), the preventive maintenance unit (515) instructs preventive maintenance on the equipment, Based on the preventive maintenance instructions for corrosion of the equipment issued by the preventive maintenance unit (515), the results of the integrity evaluation of the equipment by the integrity monitoring unit (514), and the results of the radiation dose evaluation of workers by the radiation dose evaluation unit (518), the life cycle management unit (516) creates a repair plan for the nuclear power plant (P), A system for optimizing the repair plan of a nuclear power plant, characterized by comprising the following features.

[0082] This will allow for the optimization of the repair plan for the nuclear power plant, taking into account the assessment of radiation exposure levels for workers at the plant.

[0083] [Claim 2] The soundness monitoring unit (514) is further provided with a fuel operation planning unit (517) that outputs information on the operation plan of the fuel used by the nuclear power plant (P), The integrity monitoring unit (514) reflects the fuel operation plan used by the nuclear power plant (P) in the evaluation of the integrity of the equipment constituting the nuclear power plant (P). The system for optimizing the repair plan of a nuclear power plant according to feature 1.

[0084] This allows for the optimization of the nuclear power plant's maintenance plan by taking into account information on the operational plan for the fuel used by the nuclear power plant.

[0085] [Claim 3] The fuel operation plan information output by the fuel operation plan unit (517) includes information on the number of fuel replacements and / or fuel shuffling units. The system for optimizing the repair plan of a nuclear power plant according to feature 2.

[0086] This allows for the optimization of the nuclear power plant's maintenance plan by taking into account information on the number of fuel replacements and / or fuel shuffling units used by the nuclear power plant.

[0087] [Claim 4] The fuel operation planning unit (517) outputs one of the following: information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys; information on the thinning rate of stainless steel, carbon steel, and nickel-based alloys; information on the corrosion rate of carbon steel; information on the thinning rate of carbon steel; and information on the amount of platinum deposited. The system for optimizing the repair plan of a nuclear power plant according to feature 3.

[0088] This allows for the optimization of the nuclear power plant's maintenance plan by outputting information on the corrosion rate of stainless steel, carbon steel, and nickel-based alloys, the thinning rate of stainless steel, carbon steel, and nickel-based alloys, the corrosion rate of carbon steel, the thinning rate of carbon steel, and the amount of platinum deposited, based on information on the number of fuel replacements and / or fuel shufflings used by the nuclear power plant.

[0089] [Claim 5] The radiation dose evaluation unit (518) reflects the fuel operation plan used by the nuclear power plant in the evaluation of the radiation dose received by the workers of the nuclear power plant (P). The system for optimizing the repair plan of a nuclear power plant according to feature 2.

[0090] This allows for a more accurate assessment of the radiation dose received by workers at nuclear power plants, based on information regarding the number of fuel replacements and / or fuel shufflings used in the plants, and enables the optimization of maintenance plans for nuclear power plants.

[0091] [Claim 6] The aforementioned nuclear power plant (P) is a power plant that includes a reactor pressure vessel, The environmental information detected by the detection unit (511) includes any of the following: the type and concentration of chemical substances contained in the reactor water of the reactor pressure vessel during operation, the type of material, the radiation dose, and construction data from the time of construction. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

[0092] This will allow for the optimization of repair plans for power plants, including reactor pressure vessels.

[0093] [Claim 7] The aforementioned equipment relates to the insertion of control rods and the internal structure of the reactor. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

[0094] This allows for the optimization of repair plans for control rods and in-core structures in power plants, including reactor pressure vessels.

[0095] [Claim 8] The aforementioned equipment is one of the following: reactor pressure vessel, shroud, shroud support, jet pump, grid plate, fuel support plate, or main piping connecting equipment whose safety importance and power generation importance are higher than a threshold. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

[0096] This allows for the optimization of repair plans for the reactor pressure vessel, shroud, shroud support, jet pump, grid plate, fuel support plate, and major piping connecting equipment whose safety importance and power generation importance are above a threshold in power plants that include the reactor pressure vessel.

[0097] [Claim 9] The aforementioned equipment is composed of any of the following: a structure, a weld line, and piping. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

[0098] This allows for the optimization of repair plans for equipment, including structures, welds, and piping, in power plants, including reactor pressure vessels.

[0099] [Claim 10] The detection unit (511) detects environmental information of the operating nuclear power plant (P), The Integrity Monitoring Unit (514) continuously monitors the integrity of the equipment constituting the nuclear power plant (P) based on environmental information of the nuclear power plant (P) in operation and the importance of the equipment constituting the nuclear power plant (P), Based on the monitoring results from the soundness monitoring unit (514), the exposure dose evaluation unit (518) evaluates the exposure dose of the worker, Based on the results of the integrity evaluation of the equipment during operation by the integrity monitoring unit (514) and the results of the worker's exposure dose evaluation by the exposure dose evaluation unit (518), the preventive maintenance unit (515) instructs preventive maintenance for the equipment. The steps include: a life cycle management unit (516) creating a repair plan for the nuclear power plant based on preventive maintenance instructions for corrosion of the equipment issued by the preventive maintenance unit (515) and the results of the integrity assessment of the equipment by the integrity monitoring unit (514); A method for optimizing the repair plan of a nuclear power plant, characterized by performing the following.

[0100] This will allow for the optimization of the repair plan for the nuclear power plant, taking into account the assessment of radiation exposure levels for workers at the plant.

[0101] [Claim 11] Computers Procedure for detecting environmental information of a nuclear power plant (P) in operation. A procedure for continuously monitoring the integrity of the equipment constituting the nuclear power plant (P) based on environmental information of the nuclear power plant (P) during operation and information on the importance of the equipment constituting the nuclear power plant (P), A procedure for evaluating the radiation dose of workers based on the results of monitoring the integrity of the equipment constituting the nuclear power plant (P), A procedure for instructing preventive maintenance on the equipment based on the results of the integrity assessment of the equipment during operation and the results of the radiation dose assessment of the workers. A procedure for creating a repair plan for the nuclear power plant (P) based on preventive maintenance instructions for corrosion of the equipment, the results of the soundness assessment of the equipment, and the results of the radiation dose assessment of the workers of the nuclear power plant (P). A program to optimize the repair plans for nuclear power plants in order to implement this.

[0102] This will allow for the optimization of the repair plan for the nuclear power plant, taking into account the assessment of radiation exposure levels for workers at the plant.

[0103] Variant form The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. It is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0104] Each of the above configurations, functions, processing units, and processing means may be implemented in part or in whole by hardware, such as an integrated circuit. Each of the above configurations and functions may also be implemented in software by a processor interpreting and executing a program that implements each function. Information such as programs, tables, and files that implement each function can be stored in a recording device such as memory, a hard disk, or an SSD (Solid State Drive), or on a recording medium such as a flash memory card or a DVD (Digital Versatile Disk).

[0105] In each embodiment, the control lines and information lines shown are those deemed necessary for explanation and do not necessarily represent all control lines and information lines in the actual product. In practice, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0106] S Repair Plan Optimization System 1. Local output area monitor outer tube 20. Reactor pressure vessel 21. Reactor containment vessel 22 Turbines 23 Recirculation system piping 24. Reactor purification system 25 Core 26 Recirculation pump 27 Main steam piping 28 Condenser 29 Condensate piping 30 Water supply piping 31 Off-gas piping 32. Dose Rate Monitor 33 Drain piping 34a~34d Water quality measuring device 35a~35c Sampling piping 35d Sampling piping 4. Corrosion potential sensor 5 Servers 51 CPU 511 Detection unit 512 Importance classification section 513 Periodic Inspection Information Reception Department 514 Health Monitoring Department 515 Preventive Maintenance Department 516 Lifecycle Management Department 517 Fuel Operations Planning Department 518 Exposure Dose Assessment Department 519 Fuel Change / Shuffling Database 520 Radiation Dose Database 52 ROM 53 RAM 54 Control section 55 Display section 56 Communications Department 57 Memory section 58. Sensor for providing information on the operating environment 6 terminals 61 CPU 62 ROM 63 RAM 64 Touchscreen displays 66 Communications Department 67 Memory section

Claims

1. A detection unit that detects environmental information of a nuclear power plant in operation, A health monitoring unit that continuously monitors the health of the equipment constituting the nuclear power plant based on the environmental information of the nuclear power plant in operation and the importance information of the equipment constituting the nuclear power plant, Based on the monitoring results of the nuclear power plant by the aforementioned health monitoring unit, the exposure dose evaluation unit evaluates the exposure dose received by the workers of the nuclear power plant, Based on the results of the integrity evaluation of the equipment during operation by the integrity monitoring unit and the results of the worker's radiation dose evaluation by the radiation dose evaluation unit, the preventive maintenance unit instructs preventive maintenance on the equipment. A Life Cycle Management Unit creates a repair plan for the nuclear power plant based on preventive maintenance instructions for corrosion of the equipment issued by the Preventive Maintenance Unit, the results of the equipment integrity assessment by the Integrity Monitoring Unit, and the results of the worker radiation dose assessment by the Radiation Dose Assessment Unit. A system for optimizing the repair plan of a nuclear power plant, characterized by comprising the following features.

2. The aforementioned health monitoring unit is further provided with a fuel operation planning unit that outputs information on the operation plan of the fuel used by the nuclear power plant. The soundness monitoring unit reflects the fuel operation plan used by the nuclear power plant in the evaluation of the soundness of the equipment constituting the nuclear power plant. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

3. The fuel operation plan information output by the fuel operation planning unit includes information on the number of fuel replacements and / or fuel shuffling units. The system for optimizing the repair plan of a nuclear power plant according to feature 2.

4. The fuel operation planning unit outputs one of the following: information on the corrosion rate of stainless steel, information on the corrosion rate of carbon steel, information on the corrosion rate of nickel-based alloys, information on the thinning rate of stainless steel, information on the thinning rate of carbon steel, information on the thinning rate of nickel-based alloys, information on the corrosion rate of carbon steel, information on the thinning rate of carbon steel, or information on the amount of platinum deposited. The system for optimizing the repair plan of a nuclear power plant according to feature 3.

5. The radiation dose evaluation unit reflects the fuel operation plan used by the nuclear power plant in the evaluation of the radiation dose received by the workers of the nuclear power plant. The system for optimizing the repair plan of a nuclear power plant according to feature 2.

6. The aforementioned nuclear power plant is a power plant that includes a reactor pressure vessel, The environmental information detected by the detection unit includes any of the following: the type and concentration of chemical substances contained in the reactor water of the reactor pressure vessel during operation, the type of material, the radiation dose, and construction data from the time of construction. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

7. The aforementioned equipment relates to the insertion of control rods and the internal structure of the reactor. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

8. The aforementioned equipment is one of the following: reactor pressure vessel, shroud, shroud support, jet pump, grid plate, fuel support plate, or main piping connecting equipment whose safety importance and power generation importance are higher than a threshold. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

9. The aforementioned equipment is composed of any of the following: a structure, a weld line, and piping. The system for optimizing the repair plan of a nuclear power plant according to feature 1.

10. The detection unit detects environmental information of a nuclear power plant in operation, The Integrity Monitoring Unit continuously monitors the integrity of the equipment constituting the nuclear power plant based on environmental information of the nuclear power plant in operation and the importance of the equipment constituting the nuclear power plant, Based on the monitoring results from the aforementioned health monitoring unit, the exposure dose evaluation unit evaluates the exposure dose of the worker. Based on the results of the integrity evaluation of the equipment during operation by the integrity monitoring unit and the results of the worker's radiation dose evaluation by the radiation dose evaluation unit, the preventive maintenance unit instructs preventive maintenance on the equipment. The steps include: a life cycle management unit creating a repair plan for the nuclear power plant based on preventive maintenance instructions for corrosion of the equipment issued by the preventive maintenance unit and the results of the equipment integrity assessment by the integrity monitoring unit; A method for optimizing the repair plan of a nuclear power plant, characterized by performing the following.

11. Computers Procedures for detecting environmental information at a nuclear power plant in operation. A procedure for continuously monitoring the integrity of the equipment constituting the nuclear power plant, based on environmental information of the nuclear power plant during operation and information on the importance of the equipment constituting the nuclear power plant. A procedure for evaluating the radiation dose of workers based on the results of monitoring the integrity of the equipment constituting the nuclear power plant, A procedure for instructing preventive maintenance on the equipment based on the results of the integrity assessment of the equipment during operation and the results of the radiation dose assessment of the workers. A procedure for creating a repair plan for the nuclear power plant based on preventive maintenance instructions for corrosion of the equipment, the results of the integrity assessment of the equipment, and the results of the radiation dose assessment of the workers of the nuclear power plant. A program to optimize the repair plans for nuclear power plants in order to implement this.

Images