Nuclear power plant SSCs lifetime management method

Abstract

The invention specifically relates to a nuclear power plant SSCs life period management method, which belongs to the technical field of midfield period operation and maintenance scheme formulation, and comprises the following steps: step 1, screening out SSCs needing life period management; 2, determining the boundary, the range and the function of the SSCs; step 3, SSCs operation and maintenance experience examination is carried out; step 4, performing multi-dimensional evaluation on the SSCs; 5, making an SSCs life period management scheme; step 6, evaluating the economical efficiency of the SSCs lifetime management scheme; step 7, selecting an optimal SSCs lifetime management scheme; step 8, executing the SSCs lifetime management scheme; step 9, evaluating the effect of the SSCs lifetime management scheme; and step 10, optimizing the SSCs lifetime management scheme. According to the method, through multi-dimensional comprehensive evaluation and intelligent decision support, the cost minimization and the reliability maximization of the equipment in the whole life cycle are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medium-term operation and maintenance scheme making, in particular to a nuclear power plant SSCs life cycle management method, which is suitable for equipment medium and long-term operation and maintenance scheme making, whole life cycle management and equipment whole life cycle cost economic improvement. BACKGROUND

[0002] Currently, equipment medium and long-term management mostly adopts aging management combined with preventive maintenance mode, which has four contradictions:

[0003] 1. Equipment aging and resource limitation contradiction: high-value equipment (such as nuclear steam generator) ages rapidly, but the maintenance budget allocation lacks scientific basis;

[0004] 2. Short-term cost and long-term asset value-added contradiction: excessive maintenance (such as early replacement) leads to waste of funds, and delayed maintenance may cause unplanned shutdown;

[0005] 3. One-sided technical evaluation contradiction: the existing method only evaluates the aging condition, and the preventive maintenance management only focuses on the equipment usage and defects, without comprehensive evaluation.

[0006] 3. Technical feasibility and economic optimality contradiction: the existing method focuses on one-sided technical evaluation, ignoring economic quantitative analysis. SUMMARY

[0007] In view of the problems of technical fragmentation, resource mismatch and economic insufficiency in high-value equipment medium and long-term operation and maintenance management, the present application provides a nuclear power plant SSCs life cycle management method, which is a dynamic closed-loop operation and maintenance scheme making method, realizes the minimization of equipment whole life cycle cost and the maximization of reliability through multi-dimensional comprehensive evaluation and intelligent decision support.

[0008] In order to achieve the above purpose, the present application provides the following technical scheme:

[0009] A nuclear power plant SSCs life cycle management method, comprising the following steps:

[0010] Step one, screening out SSCs needing life cycle management;

[0011] Step two, determining the boundary, range and function of SSCs;

[0012] Step three, SSCs operation and maintenance experience review;

[0013] Step four, multi-dimensional evaluation of SSCs;

[0014] Step five, making SSCs life cycle management scheme;

[0015] Step six, economic evaluation of SSCs life management scheme;

[0016] Step seven, selection of the optimal SSCs life management scheme;

[0017] Step eight, implementation of the SSCs life management scheme;

[0018] Step nine, evaluation of the effect of the SSCs life management scheme;

[0019] Step ten, optimization of the SSCs life management scheme.

[0020] As one of the ways to achieve, step one, screening of SSCs requiring life management, includes the following steps:

[0021] Setting an economic threshold to determine whether the value of SSCs is greater than or equal to the economic threshold; if the value of SSCs is less than the economic threshold, it is determined that SSCs do not require life management; if the value of SSCs is greater than or equal to the economic threshold, it is further determined whether SSCs contain whole replacement or core component refurbishment in the preventive maintenance schedule;

[0022] If SSCs contain whole replacement or core component refurbishment in the preventive maintenance schedule, it is determined that SSCs do not require life management; if SSCs do not contain whole replacement or core component refurbishment in the preventive maintenance schedule, it is further determined whether SSCs can be replaced or core component refurbished in daily overhaul or regular overhaul;

[0023] If SSCs can be replaced or core component refurbished in daily overhaul or regular overhaul, it is determined that SSCs do not require life management; if SSCs cannot be replaced or core component refurbished in daily overhaul or regular overhaul, it is further determined whether SSCs have design defects that cause the whole or major value components to be replaced or changed;

[0024] If SSCs have design defects that cause the whole or major value components to be replaced or changed, it is determined that SSCs require life management; if SSCs do not have design defects that cause the whole or major value components to be replaced or changed, it is further determined whether SSCs have common problems that cause the whole or major value components to be replaced or changed;

[0025] If SSCs have common problems that cause the whole or major value components to be replaced or changed, it is determined that SSCs require life management; if SSCs do not have common problems that cause the whole or major value components to be replaced or changed, it is further determined whether the operating life of SSCs meets the full life operation requirements of the nuclear power plant;

[0026] If the SSCs meet the nuclear power plant life cycle operation requirements, it is determined that the SSCs do not need to be managed; if the SSCs do not meet the nuclear power plant life cycle operation requirements, it is determined that the SSCs need to be managed.

[0027] As one of the implementable ways, step two, determining the boundary, scope and function of the SSCs, includes the following steps:

[0028] If the SSCs are systems, the boundary and scope of the system is a collection of a series of interconnected components combined together to complete a specific function; the boundary and scope of the system are determined intuitively by looking up the operation flowchart of the system; the function of the system is determined by the design reference file and safety analysis report of the system;

[0029] If the SSCs are structures, the boundary and scope of the structure is the limit of the physical space, which is determined by the structure drawing; the structure is a physical building that provides physical barriers, structural support and link isolation, and its function focuses on structural integrity and containment capacity;

[0030] If the SSCs are components, when the SSCs are pressure equipment, the boundary of the SSCs is the first isolation valve outside the pressure vessel and its accessories; when the SSCs are other equipment, the boundary and scope of the SSCs are the physical outline or functional unit of the SSCs themselves; the component is the basic execution unit of the system or structure, and its function is to execute the effect and possible consequences achieved by the component.

[0031] As one of the implementable ways, step three, SSCs operation and maintenance experience review, includes the following steps:

[0032] Obtain external operation and maintenance experience data, internal operation and maintenance history data and existing preventive maintenance scheme of the SSCs and list them in table form;

[0033] Compare the external operation and maintenance experience data and internal operation and maintenance history data of the SSCs with the existing preventive maintenance scheme respectively, evaluate whether the existing preventive maintenance scheme of the SSCs can avoid the faults in the external operation and maintenance experience data and internal operation and maintenance history data, and sort out the improvement suggestions for the operation and maintenance of the SSCs;

[0034] The external operation and maintenance experience data of the SSCs include the faults of the SSCs, their root causes and treatment measures, and the existing preventive maintenance measures of the SSCs, which provide reference for the operation and maintenance management optimization of the SSCs in the nuclear power plant;

[0035] The internal operation and maintenance history data of the SSCs include corrective maintenance work orders, historical operation logs and historical major change data of the SSCs.

[0036] As one of the ways to achieve, in step four, SSCs multi-dimensional assessment, including SSCs life assessment, SSCs aging problem assessment and SSCs technology obsolescence assessment.

[0037] As one of the ways to achieve, SSCs life includes the expected life analysis of core components, which provides the basis for subsequent modification or replacement; the core components are the components that will affect the function of SSCs and cannot be replaced by daily overhaul;

[0038] SSCs life is evaluated by one or more of the following methods:

[0039] 1. Research to obtain internal and external operation and maintenance experience of SSCs, refer to the relevant suggestions given by the manufacturer, and list the expected life of SSCs and its core components;

[0040] 2. Research to obtain peer replacement cycle for comparison and further discrimination;

[0041] 3. Research to obtain domestic power plant failure rate for comparison and discrimination;

[0042] 4. Verify and evaluate by test or entrust professional institutions to evaluate.

[0043] As one of the ways to achieve, SSCs aging problem assessment, including the following steps:

[0044] 1. Determine the four parameters of SSCs component name, degradation prone position, material type and operating environment;

[0045] 2. According to the parameters of SSCs, combined with the experience and lessons learned from the review of nuclear power plant and industry operation experience, determine the mechanisms that may not have been observed in nuclear power plants for aging management;

[0046] 3. Research the aging mechanism and aging effect of the same SSCs in peer power plants;

[0047] 4. Conduct in-depth interviews with field personnel to obtain missing information and solicit opinions on possible failure mechanisms and alternative methods for managing aging and scrapping;

[0048] 5. Review the above information to determine where the existing plan is excessive, sufficient or insufficient to address aging management and scrapping issues;

[0049] 6. Review SSCs for existing or potential aging issues and whether existing management measures at the nuclear power plant are adequate to detect or mitigate the existing or potential aging issues in a timely manner, determine the current method or plan for addressing each aging mechanism, typically including periodic preventive maintenance, predictive or diagnostic based maintenance, periodic replacement, corrective maintenance after failure, and failure unavailability.

[0050] As one of the implementable ways, the SSCs technology obsolescence assessment includes assessing the obsolescence status of SSCs according to a pre-set SSCs obsolescence assessment table, providing a basis for subsequent modification or replacement of SSCs;

[0051] As one of the implementable ways, step five, developing a suitable SSCs operation and maintenance plan, includes the following steps:

[0052] Step 501, developing a SSCs operation and maintenance plan according to the operation and maintenance experience of step two and the technical assessment results of step four;

[0053] Step 502, developing a SSCs life management plan according to the SSCs operation and maintenance plan.

[0054] As one of the implementable ways, the SSCs operation and maintenance plan includes continuing to use the current operation and maintenance plan.

[0055] As one of the implementable ways, the SSCs operation and maintenance plan further includes optimizing the current operation and maintenance plan, including preventive maintenance, predictive maintenance, condition monitoring, inspection, testing; and taking measures to mitigate the environmental or operating conditions of SSCs.

[0056] As one of the implementable ways, the SSCs operation and maintenance plan further includes making changes or modifications to the design of SSCs.

[0057] As one of the implementable ways, the SSCs operation and maintenance plan further includes replacement or renovation.

[0058] As one of the implementable ways, the SSCs operation and maintenance plan further includes SSCs running to failure, applicable to SSCs whose failure will not affect the safety or availability of the nuclear power plant;

[0059] SSCs running to failure, implementing replacement of SSCs measures or mitigating SSCs aging pressure measures;

[0060] Mitigating SSCs aging pressure measures include reducing the environmental aging pressure or operating aging pressure of SSCs, environmental aging pressure such as temperature, radiation, humidity and corrosive chemicals; operating aging pressure such as erosive flow in pipes and thermal cycling.

[0061] As one of the possible ways to achieve, step six, SSCs life management program economic evaluation, including the following steps:

[0062] The economic evaluation of the developed SSCs life management program, in the economic analysis time interval, the preventive maintenance cost, major replacement cost, expenditure, income and total expenditure of the SSCs life management program are calculated;

[0063] The preventive maintenance cost and major replacement cost of the SSCs life management program are evaluated according to the historical work order and maintenance procedure;

[0064] The expenditure of the SSCs life management program is equal to the sum of the preventive maintenance cost and major replacement cost of the SSCs life management program and the loss of electricity income due to the implementation of the SSCs life management program; the loss of electricity income due to the implementation of the SSCs life management program is set according to the practice of nuclear power plant;

[0065] The income of the SSCs life management program is equal to the income brought by the implementation of the SSCs life management program;

[0066] The total expenditure of the SSCs life management program = the expenditure of the SSCs life management program - the income of the SSCs life management program.

[0067] As one of the possible ways to achieve, step seven, the selection of the optimal SSCs life management program, including the following steps:

[0068] Considering the economy, reliability and implementation difficulty of the SSCs life management program, combining with the current situation and expectation of the nuclear power plant, focusing on maximizing the value of SSCs rather than minimizing the maintenance cost, the optimal SSCs life management program is determined.

[0069] As one of the possible ways to achieve, step nine, SSCs life management program effect evaluation, including the following steps:

[0070] After the implementation of the SSCs life management program, the health report and operation history of the SSCs are regularly reviewed to determine the new equipment vulnerabilities that need to be addressed; if a major safety accident occurs during the implementation of the SSCs life management program, the effect of the SSCs life management program is evaluated at any time.

[0071] As one of the possible ways to achieve, step ten, SSCs life management program optimization, including the following steps:

[0072] According to the implementation of the SSCs life management program, the SSCs life management program is evaluated every five years, and a new life management program is developed; if a major safety accident occurs during the implementation of the SSCs life management program, a new life management program is developed at any time;

[0073] Implement the new lifecycle management plan.

[0074] Beneficial technical effects of the present invention:

[0075] The nuclear power plant SSCs lifecycle management method of this invention achieves continuous optimization of operation and maintenance strategies and dynamic risk control through a dynamic closed-loop process of "screening-evaluation-optimization-feedback". By clarifying the screening principles and establishing a lifecycle management object screening and evaluation process model, it effectively avoids subjective judgment errors and selects the equipment that most needs medium- and long-term strategy customization, focusing efforts on critical equipment. Multi-dimensional comprehensive evaluation model technology enables coordinated decision-making based on technology, economy, and safety. It integrates pre-maintenance experience, lifecycle assessment, aging assessment, technology obsolescence scoring, and economic analysis to form a scientific decision-making framework. Through dynamic matching of equipment health status and overhaul cycle, it optimizes the implementation window and flexible window planning technology, minimizing resource scheduling and schedule conflicts. It has developed tools such as the "Lifecycle Management Equipment Screening and Evaluation Template", "Obsolution Assessment Template", and "Economic Analysis Template", and standardized templates and tool-based design technology enable rapid cross-industry replication and compliance assurance. Attached Figure Description

[0076] Figure 1 A flowchart of an embodiment for screening Service Controllers (SSCs) requiring lifetime management;

[0077] Figure 2 This is a flowchart illustrating one embodiment of the nuclear power plant SSCs life management method of the present invention. Detailed Implementation

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0079] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0080] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0081] Compared with existing aging management and pre-maintenance management models, lifecycle management is a process that combines aging management, pre-maintenance management and asset management. It aims to maintain equipment availability while effectively utilizing funds and resources. For a detailed comparison of the differences, please refer to Table 1.

[0082] Table 1: Comparison of Lifespan Management, Aging Management, and Pre-Maintenance

[0083]

[0084]

[0085] refer to Figure 2 The diagram illustrates a flowchart of an embodiment of a nuclear power plant SSCs lifecycle management method, which includes the following steps:

[0086] Step 1: Screen out SSCs that require lifecycle management;

[0087] Step 2: Determine the boundaries, scope, and functions of SSCs;

[0088] Step 3: Review of SSCs operation and maintenance experience;

[0089] Step 4: Multi-dimensional evaluation of SSCs;

[0090] Step 5: Develop an SSCs lifecycle management plan;

[0091] Step Six: Economic Evaluation of SSCs Lifetime Management Plan;

[0092] Step 7: Select the optimal SSCs lifecycle management plan;

[0093] Step 8: Implement the SSCs lifecycle management plan;

[0094] Step 9: Evaluation of the effectiveness of the SSCs lifecycle management program;

[0095] Step 10: Optimize the SSCs lifecycle management plan.

[0096] SSCs is an abbreviation for "Systems, Structures, and Components." In nuclear power plants, SSCs refer to all physical entities within the plant. The lifespan of a nuclear power plant's SSCs refers to the period from commissioning until the intended function of each physical entity ceases to reliably and safely meet design requirements. The nuclear power plant SSCs lifespan management method of this invention is applicable to the lifespan management of all physical entities within a nuclear power plant.

[0097] See Figure 1In this embodiment, as one possible approach, step one involves screening out SSCs that require lifetime management, including the following steps:

[0098] Set an economic threshold and determine whether the value of SSCs is greater than or equal to the economic threshold. If the value of SSCs is less than the economic threshold, it is determined that SSCs do not need life management. If the value of SSCs is greater than or equal to the economic threshold, it is further determined whether the SSCs include complete replacement or core component refurbishment in the preventive maintenance program.

[0099] If the preventive maintenance program includes complete replacement or core component refurbishment, then the SSCs are deemed not to require life-cycle management; if the preventive maintenance program does not include complete replacement or core component refurbishment, then it is further determined whether the SSCs can be completely replaced or core component refurbished during routine overhauls or regular maintenance.

[0100] If SSCs can be completely replaced or have their core components refurbished during routine or regular overhauls, then SSCs are deemed not to require lifecycle management. If SSCs cannot be completely replaced or have their core components refurbished during routine or regular overhauls, then it is further determined whether the SSCs have design defects that would require the replacement or alteration of the entire or critically valuable components.

[0101] If SSCs have design flaws that require the replacement or alteration of the entire or critical value components, then the SSCs are deemed to require lifecycle management; if SSCs do not have design flaws that require the replacement or alteration of the entire or critical value components, then it is further determined whether the SSCs have common problems that would require the replacement or alteration of the entire or critical value components.

[0102] If SSCs have common problems that require replacement or alteration of the entire or critically valuable components, then the SSCs are deemed to require life-cycle management; if SSCs do not have common problems that require replacement or alteration of the entire or critically valuable components, then it is further determined whether the operating life of the SSCs meets the full life-cycle operating requirements of the nuclear power plant.

[0103] If the operating life of SSCs meets the full life-cycle operating requirements of the nuclear power plant, then the SSCs are deemed not to require life-cycle management; if the operating life of SSCs does not meet the full life-cycle operating requirements of the nuclear power plant, then the SSCs are deemed to require life-cycle management.

[0104] In this embodiment, as one possible approach, the preventive maintenance strategy of SSCs in the preventive maintenance outline is searched to determine whether the SSCs include overall replacement or core component refurbishment in the preventive maintenance outline; if the preventive maintenance strategy of the SSCs includes overall replacement or core component refurbishment, then the SSCs are determined to include overall replacement or core component refurbishment in the preventive maintenance outline; if the preventive maintenance strategy of the SSCs does not include overall replacement or core component refurbishment, or if the SSCs do not have a preventive maintenance strategy, then the SSCs are determined to not include overall replacement or core component refurbishment in the preventive maintenance outline.

[0105] By consulting the technical specifications of SSCs, determine whether SSCs can be completely replaced or have their core components refurbished during routine or regular overhauls. If the technical specifications of an SSC indicate that it can be completely replaced or have its core components refurbished during routine or regular overhauls, then it is determined that an SSC can be completely replaced or have its core components refurbished during routine or regular overhauls.

[0106] By reviewing historical defect and status reports of SSCs during their operation at the nuclear power plant, it is determined whether any SSCs have design flaws that would necessitate the replacement or alteration of overall or critically valuable components. If any design flaws are found in the historical defect and status reports of SSCs during their operation at the nuclear power plant, it is confirmed that the SSCs have such design flaws. Conversely, if no design flaws are found in the historical defect and status reports of SSCs during their operation at the nuclear power plant, it is confirmed that the SSCs do not have such design flaws.

[0107] By identifying whether SSCs share common issues with other power plants in the same industry that lead to the need for replacement or alteration of the entire or critically valuable components; if so, it is determined that SSCs have common issues that lead to the need for replacement or alteration of the entire or critically valuable components; if not, it is determined that SSCs do not have common issues that lead to the need for replacement or alteration of the entire or critically valuable components.

[0108] By reviewing the life-related technical documents of SSCs, it is determined whether the operational life of the SSCs meets the full life-cycle operational requirements of the nuclear power plant. If the life-related technical documents of the SSCs indicate that the operational life of the SSCs meets the full life-cycle operational requirements of the nuclear power plant, then the operational life of the SSCs is determined to meet the full life-cycle operational requirements of the nuclear power plant. If the life-related technical documents of the SSCs do not indicate that the operational life of the SSCs meets the full life-cycle operational requirements of the nuclear power plant, then the operational life of the SSCs is determined not to meet the full life-cycle operational requirements of the nuclear power plant.

[0109] In this embodiment, as one possible approach, in step one, the economic threshold is 10 million yuan; when the value of SSCs does not exist, the value of similar SSCs is used to replace the value of SSCs.

[0110] Defining the boundaries, functions, and scope of SSCs is fundamental to subsequent SSC technology evaluation. Before commencing SSC technology evaluation, it is necessary to assess the boundaries, scope, and functions of SSCs as the objects of subsequent technology evaluation.

[0111] In this embodiment, as one possible approach, step two, determining the boundaries, scope, and functions of SSCs, includes the following steps:

[0112] If SSCs are systems, the boundaries and scope of a system are a collection of interconnected components that are grouped together to perform a specific function. The boundaries and scope of a system can be intuitively determined by looking up the system's operation flowchart. Each system has detailed design baseline documents and safety analysis reports, which clearly define the system's functions, composition, design baselines, operating parameters, and interfaces with other systems and structures. The functions of a system are determined through its design baseline documents and safety analysis reports.

[0113] If SSCs are structures, the boundaries and extent of the structures are the limits of the physical space, which are determined by the structure drawings; structures are physical buildings that provide physical barriers, structural support and link isolation, and their function focuses on structural integrity and containment capacity.

[0114] If SSCs are components, when SSCs are pressure equipment, the boundary of an SSC is the first isolation valve outside the pressure vessel and its accessories; when SSCs are other equipment, the boundary and scope of an SSC are the physical outline or functional unit of the SSC itself, generally the equipment body supplied by the manufacturer and the subsystems, sub-equipment or sub-components installed on the equipment body; a component is the basic execution unit of a system or structure, and its function is to execute the effect achieved by the component and the possible consequences.

[0115] In this embodiment, as one possible approach, step three, the review of SSCs operation and maintenance experience, includes the following steps:

[0116] Obtain external operation and maintenance experience data, internal operation and maintenance historical data, and existing preventive maintenance plans for SSCs and list them in tabular form;

[0117] Compare the external maintenance experience data and internal maintenance history data of SSCs with the existing preventive maintenance plan to evaluate whether the existing preventive maintenance plan of SSCs can avoid the failures in the external maintenance experience data and internal maintenance history data, and compile improvement suggestions for SSCs maintenance.

[0118] External operation and maintenance experience data for SSCs includes SSC failures, their root causes and handling measures, as well as existing preventive maintenance measures for SSCs, providing a reference for optimizing the operation and maintenance management of SSCs in this nuclear power plant.

[0119] SSCs' internal maintenance history data includes corrective maintenance work orders, historical operation logs, and historical major change data.

[0120] In this embodiment, as one possible approach, step four involves a multi-dimensional evaluation of SSCs, including SSCs lifetime assessment, SSCs aging problem assessment, and SSCs technology obsolescence assessment.

[0121] In this embodiment, as one possible approach, the lifespan of SSCs includes the expected lifespan analysis of core components, providing a basis for subsequent modifications or replacements; core components are those that affect the function of SSCs and cannot be replaced during routine overhauls.

[0122] The lifetime of SSCs is evaluated using one or more of the following methods:

[0123] 4. Conduct research to obtain internal and external operation and maintenance experience of SSCs, and refer to the relevant suggestions given by the manufacturer to list the expected life of SSCs and their core components.

[0124] 5. Conduct research to obtain information on competitors' replacement cycles for comparison and then make a judgment;

[0125] 6. Conduct research to obtain domestic power plant failure rates for comparison and judgment;

[0126] 4. Verify and evaluate through testing, such as using accelerated aging simulation test models to determine the remaining lifespan and effective service time of the equipment; or entrust a professional organization to conduct an assessment.

[0127] In this embodiment, as one possible approach, the SSCs aging problem assessment includes the following steps:

[0128] 1. Locate the manuals and drawings of SSCs and list the four parameters of SSCs in order: component name, parts prone to degradation, material type, and operating environment;

[0129] 2. Based on the parameters of SSCs and lessons learned from the review of nuclear power plant and industry operating experience, identify mechanisms that may not yet be observed in nuclear power plants that are important for aging management.

[0130] 3. Investigate the aging mechanism and aging effect of similar SSCs in peer power plants;

[0131] 4. Conduct in-depth interviews with on-site personnel to obtain missing information and solicit opinions on possible failure mechanisms and alternative methods for managing aging and obsolescence;

[0132] 5. Review the above information to determine in what areas the existing plan is excessive, adequate, or insufficient in addressing aging management and obsolescence issues;

[0133] 6. Review existing or potential aging issues of SSCs according to the SSCs Aging Management Review Checklist, and determine whether the existing management measures of the nuclear power plant can detect or mitigate existing or potential aging issues of SSCs in a timely manner. Identify the current methods or plans used to address each aging mechanism, which typically include regular preventive maintenance, predictive or diagnostic-based maintenance, regular replacement, corrective maintenance after failure operation, and failure-unreliable maintenance.

[0134] Table 4 SSCs Aging Management Review Form

[0135]

[0136] In this embodiment, as one possible approach, SSCs technology obsolescence assessment includes assessing the obsolescence status of SSCs according to a preset SSCs obsolescence assessment table, providing a basis for subsequent modification or replacement of SSCs.

[0137] The SSCs obsolescence assessment table is shown in the table below:

[0138] Table 5. SSCs Obsolescence Assessment Table

[0139]

[0140]

[0141] In this embodiment, as one possible approach, step five involves developing a suitable SSCs operation and maintenance plan, including the following steps:

[0142] Step 501: Based on the operation and maintenance experience in Step 2 and the technical evaluation results in Step 4, formulate an SSCs operation and maintenance plan.

[0143] Step 502: Based on the SSCs operation and maintenance plan, formulate the SSCs lifecycle management plan. There are multiple SSCs operation and maintenance plans, and the final SSCs operation and maintenance plan is the SSCs lifecycle management plan.

[0144] In this embodiment, as one possible approach, the SSCs operation and maintenance solution includes continuing to use the current operation and maintenance solution.

[0145] In this embodiment, as one possible approach, the SSCs operation and maintenance solution also includes optimizing the current operation and maintenance solution;

[0146] Optimizing the current maintenance program aims to refine the current maintenance schedule by increasing or decreasing maintenance volume to reflect the results of aging assessments. For example, increasing preventative maintenance on parts to avoid major failures that could lead to forced downtime may be cost-effective. Conversely, if the current maintenance schedule is excessive, maintenance volume can be reduced without compromising safety, reliability, or availability. However, the purpose of lifecycle management planning is not to become another preventative maintenance optimization plan. To a large extent, we assume that an effective maintenance optimization process has already been completed, and lifecycle management planning receives that information as a starting point.

[0147] Maintenance methods to be considered include preventative maintenance, predictive maintenance, condition monitoring, inspection, and testing. Additionally, measures may be taken to mitigate the environmental or operating conditions of SSCs.

[0148] In this embodiment, as one possible approach, the SSCs operation and maintenance solution also includes making changes or modifications to the SSCs design;

[0149] Optimize the lifecycle cost of SSCs by changing or modifying their design. For example, replace poorly designed SSCs with an improved design that requires less maintenance, or remove a control system function that has been determined to provide little added protection but is likely to lead to an emergency shutdown.

[0150] In this embodiment, as one possible approach, the SSCs maintenance solution also includes replacement or refurbishment;

[0151] Replacement or refurbishment, which includes physically replacing the entire SSC, replacing existing parts with upgraded or improved parts, or refurbishing / overhauling.

[0152] When the lifespan or performance trends recommended by the SSC manufacturer indicate that the SSCs need to be replaced or refurbished, physical replacement or refurbishment is appropriate. Typically, replacement will improve material performance, such as upgrading the water supply lines to stainless steel.

[0153] SSC replacement or refurbishment includes planned periodic maintenance, performance enhancement, or when other methods of management are no longer feasible or economically infeasible due to aging. SSC replacement or refurbishment is often a last resort when normal maintenance and monitoring measures are no longer applicable.

[0154] Most long-term lifecycle management programs consist of a maintenance / monitoring phase and a replacement / refurbishment phase. No matter how good the maintenance / monitoring plan is, if it operates long enough, parts will eventually need to be replaced or refurbished. The tricky question is often how long a part will last.

[0155] The transition from maintenance / monitoring to replacement / renovation can be an expensive and time-consuming process. Therefore, it is crucial to anticipate replacement or renovation needs as early as possible. This gives power companies more time to assess and implement the lowest-cost alternatives. Implementing a replacement or renovation typically involves retrofit planning and budgeting, along with a condition-based assessment of the necessary timeframe.

[0156] The following are the factors to consider when determining whether to refurbish or replace an SSCs maintenance solution:

[0157] 1. Can the renovation be carried out online without affecting the power operation of the nuclear power plant?

[0158] 2. Can the overhaul be postponed to the planned refueling overhaul and carried out during the overhaul period without delay?

[0159] 3. Is refurbishment or repair a permanent solution or does it need to be repeated periodically, for example, when the root cause has not been determined?

[0160] 4. Has the candidate refurbishment addressed obsolescence issues? For example, are spare parts available now and in the foreseeable future?

[0161] 5. Have the candidate refurbishment or repair techniques (such as welding processes, code repair, or material compatibility) been validated by industry experience?

[0162] 6. Have the key aspects of the refurbishment or replacement been assessed in terms of cost, schedule, and system performance / reliability (e.g., inlet-outlet, cranes or lifting / transportation equipment, scaffolding, cleanroom, disposal of replaced items, testing-inspection, configuration compatibility)?

[0163] 7. If replacement is to be considered, is it a physical replacement or a replacement with new technology / upgraded technology (capital and O&M costs)?

[0164] 8. If new or upgraded technologies are applied, have the materials, supports, power, control, cooling, vibration resistance, EQ, licenses, documentation, quality assurance, etc. of the component interfaces been evaluated?

[0165] 9. How is the user experience of the new technology in similar applications? Are there any guarantees regarding performance improvements (such as availability, reliability, failure rate, and condition)?

[0166] 10. Will the maintenance, inspection, and parts requirements increase or decrease with the new replacement or refurbishment technology?

[0167] 11. Has the long-term plan included a budget or forecast for replacement or renovation?

[0168] In this embodiment, as one possible approach, the SSCs operation and maintenance scheme also includes SSCs that operate to a fault, and the applicable fault will not affect the safety or availability of the nuclear power plant.

[0169] When SSCs fail, implement measures to replace SSCs or reduce the aging pressure on SSCs.

[0170] Measures to reduce the aging stress of SSCs include reducing the environmental aging stress or operational aging stress of SSCs. Environmental aging stresses include temperature, radiation, humidity and corrosive chemicals; operational aging stresses include erosive flow and thermal cycling in pipelines.

[0171] In this embodiment, as one possible approach, step six, the economic evaluation of the SSCs lifecycle management scheme, includes the following steps:

[0172] Assess the economics of the developed SSCs life management program, and calculate the preventive maintenance cost, major replacement cost, expenditure, benefits and total expenditure of the SSCs life management program within the economic analysis time period;

[0173] The preventive maintenance costs and major replacement costs of the SSCs lifecycle management plan are assessed based on historical work orders and maintenance procedures to ensure reasonableness;

[0174] The expenditure of the SSCs life management program equals the sum of the preventive maintenance costs and major replacement costs of the SSCs life management program, plus the electricity revenue lost from implementing the SSCs life management program; the sum of the electricity revenue lost from implementing the SSCs life management program is set according to nuclear power plant practice.

[0175] The benefits of an SSCs lifecycle management plan are equal to the benefits of implementing an SSCs lifecycle management plan.

[0176] Total expenditure of SSCs lifecycle management program = expenditure of SSCs lifecycle management program - benefits of SSCs lifecycle management program.

[0177] In this embodiment, as one possible approach, step seven, selecting the optimal SSCs lifecycle management scheme, includes the following steps:

[0178] Taking into account the economics, reliability, and implementation difficulty of the SSCs life management plan, and combining the current operating status and expectations of the nuclear power plant, the focus is on maximizing the value of SSCs rather than minimizing maintenance costs, to determine the optimal SSCs life management plan.

[0179] The goal of lifecycle management is to select alternative O&M solutions for each SSC that deliver optimal safety, reliability, and cost-effectiveness throughout the facility's lifespan. The best alternative O&M solution may not be the lowest cost. The optimal strategy must represent the value judgment of the responsible engineer / manager, considering all applicable factors such as safety, reliability, cost, failure risk, NRC regulations, public concern, and the overall objectives of the plant and the company. Engineering and management judgment are crucial because it is difficult to allocate absolute failure risk and cost to most of these factors.

[0180] Optimal life management strategies are almost always closely related to the planned life of the facility. One approach may be best suited for a plant planned to operate for a few more years, while another may be best suited for a plant planned to operate for more than 30 years. If a target plant life has not yet been specified, it may be necessary to perform economic modeling of the range of plant life options under consideration.

[0181] These may include 1) early shutdown, 2) operation to the end of the original license life, and 3) operation to a typical 20-year license renewal. However, please note that comparisons between different lifecycle management schemes can only be made for a given operating life. Comparisons between alternative lifecycle management plans with different plant life assumptions can only be made through plant-level economic assessments.

[0182] In this embodiment, as one possible approach, step nine, evaluating the effectiveness of the SSCs lifecycle management scheme, includes the following steps:

[0183] After the SSCs lifecycle management program is implemented, the health reports and operational history of the SSCs will be reviewed every five years to identify new equipment vulnerabilities that need to be addressed. If a major security incident occurs during the implementation of the SSCs lifecycle management program, the effectiveness of the SSCs lifecycle management program will be evaluated at any time.

[0184] In this embodiment, as one possible approach, step ten, SSCs lifecycle management scheme optimization, includes the following steps:

[0185] Based on the implementation of the SSCs life management plan, the SSCs life management plan will be evaluated every five years, and a new life management plan will be developed; if a major safety incident occurs during the implementation of the SSCs life management plan, a new life management plan will be developed immediately.

[0186] Implement the new lifecycle management plan.

[0187] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for life-cycle management of nuclear power plant SSCs, characterized in that, Includes the following steps: Step 1: Screen out SSCs that require lifecycle management; Step 2: Determine the boundaries, scope, and functions of SSCs; Step 3: Review of SSCs operation and maintenance experience; Step 4: Multi-dimensional evaluation of SSCs; Step 5: Develop an SSCs lifecycle management plan; Step Six: Economic Evaluation of SSCs Lifetime Management Plan; Step 7: Select the optimal SSCs lifecycle management plan; Step 8: Implement the SSCs lifecycle management plan; Step 9: Evaluation of the effectiveness of the SSCs lifecycle management program; Step 10: Optimize the SSCs lifecycle management plan.

2. The nuclear power plant SSCs lifecycle management method according to claim 1, characterized in that, Step 1: Identify SSCs that require lifecycle management, including the following steps: Set an economic threshold and determine whether the value of SSCs is greater than or equal to the economic threshold. If the value of SSCs is less than the economic threshold, it is determined that SSCs do not need life management. If the value of SSCs is greater than or equal to the economic threshold, it is further determined whether the SSCs include complete replacement or core component refurbishment in the preventive maintenance program. If the preventive maintenance program includes complete replacement or core component refurbishment, then the SSCs are deemed not to require life-cycle management; if the preventive maintenance program does not include complete replacement or core component refurbishment, then it is further determined whether the SSCs can be completely replaced or core component refurbished during routine overhauls or regular maintenance. If SSCs can be completely replaced or have their core components refurbished during routine or regular overhauls, then SSCs are deemed not to require lifecycle management. If SSCs cannot be completely replaced or have their core components refurbished during routine or regular overhauls, then it is further determined whether the SSCs have design defects that would require the replacement or alteration of the entire or critically valuable components. If SSCs have design flaws that require the replacement or alteration of the entire or critical value components, then the SSCs are deemed to require lifecycle management; if SSCs do not have design flaws that require the replacement or alteration of the entire or critical value components, then it is further determined whether the SSCs have common problems that would require the replacement or alteration of the entire or critical value components. If SSCs have common problems that require replacement or alteration of the entire or critically valuable components, then the SSCs are deemed to require life-cycle management; if SSCs do not have common problems that require replacement or alteration of the entire or critically valuable components, then it is further determined whether the operating life of the SSCs meets the full life-cycle operating requirements of the nuclear power plant. If the operating life of SSCs meets the full life-cycle operating requirements of the nuclear power plant, then it is determined that the SSCs do not require life-cycle management. If the operating life of SSCs does not meet the full life-cycle operating requirements of a nuclear power plant, then the SSCs are deemed to require life-cycle management.

3. The nuclear power plant SSCs lifecycle management method according to claim 1, characterized in that, Step two, determine the boundaries, scope, and functions of SSCs, including the following steps: If SSCs represent a system, the system's boundaries and scope are defined as a collection of interconnected components grouped together to perform a specific function. The system's boundaries and scope can be visually determined by consulting the system's operation flowchart. The system's functions can be determined through the system's design baseline documents and safety analysis reports. If SSCs are structures, the boundaries and extent of the structures are the limits of the physical space, which are determined by the structure drawings; structures are physical buildings that provide physical barriers, structural support and link isolation, and their function focuses on structural integrity and containment capacity. If SSCs are components, when SSCs are pressure equipment, the boundary of SSCs is the first isolation valve outside the pressure vessel and its accessories; When SSCs are other devices, the boundaries and scope of SSCs are the physical outline or functional unit of the SSCs themselves; a component is the basic execution unit of a system or structure, whose function is to execute the effects achieved by the component and the possible consequences.

4. The nuclear power plant SSCs lifecycle management method according to claim 1, characterized in that, Step 3, SSCs operation and maintenance experience review, includes the following steps: Obtain external operation and maintenance experience data, internal operation and maintenance historical data, and existing preventive maintenance plans for SSCs and list them in tabular form; Compare the external maintenance experience data and internal maintenance history data of SSCs with the existing preventive maintenance plan to evaluate whether the existing preventive maintenance plan of SSCs can avoid the failures in the external maintenance experience data and internal maintenance history data, and compile improvement suggestions for SSCs maintenance. External operation and maintenance experience data for SSCs includes SSC failures, their root causes and handling measures, as well as existing preventive maintenance measures for SSCs, providing a reference for optimizing the operation and maintenance management of SSCs in this nuclear power plant. SSCs' internal maintenance history data includes corrective maintenance work orders, historical operation logs, and historical major change data.

5. The method for life management of nuclear power plant SSCs according to claim 1, characterized in that, In step four, SSCs are evaluated in multiple dimensions, including SSCs lifetime assessment, SSCs aging problem assessment, and SSCs technology obsolescence assessment. SSCs lifespan includes the expected lifespan analysis of core components, providing a basis for subsequent modifications or replacements; Core components are those that affect the function of SSCs and cannot be replaced during routine overhauls; the lifespan of SSCs is assessed using one or more of the following methods: researching and obtaining internal and external maintenance experience of SSCs, referring to relevant recommendations from manufacturers, and listing the expected lifespan recommendations for SSCs and their core components; researching and obtaining replacement cycles from peers for comparison and judgment; researching and obtaining failure rates from domestic power plants for comparison and judgment; verifying and evaluating through experiments or commissioning professional institutions to conduct assessments; The assessment of SSC aging issues includes the following steps: determining four parameters of the SSC: component name, areas prone to degradation, material type, and operating environment; based on the parameters of the SSC and lessons learned from the review of nuclear power plant and industry operating experience, identifying mechanisms that may not yet be observed in nuclear power plants and are important for aging management; and investigating the aging mechanisms and effects of similar SSCs in peer power plants. Conduct in-depth interviews with on-site personnel to obtain missing information and solicit opinions on possible failure mechanisms and alternative methods for managing aging and obsolescence; Review the above information to determine in which aspects the existing plan is excessive, adequate, or insufficient in addressing aging management and decommissioning issues; review existing or potential aging issues of SSCs according to the SSCs Aging Management Review Checklist, and determine whether the existing management measures of the nuclear power plant can promptly identify or mitigate existing or potential aging issues of SSCs; identify the current methods or plans used to address each aging mechanism, which typically include periodic preventive maintenance, predictive or diagnostic-based maintenance, periodic replacement, corrective maintenance after failure operation, and failure-unreliable maintenance; SSCs technology obsolescence assessment includes evaluating the obsolescence status of SSCs according to a pre-set SSCs obsolescence assessment form, providing a basis for subsequent SSCs modification or replacement.

6. The method for life management of nuclear power plant SSCs according to claim 1, characterized in that, Step 5: Develop a suitable SSCs operation and maintenance plan, including the following steps: Step 501: Based on the operation and maintenance experience in Step 2 and the technical evaluation results in Step 4, formulate an SSCs operation and maintenance plan. Step 502: Based on the SSCs operation and maintenance plan, formulate an SSCs lifecycle management plan; SSCs operation and maintenance solutions include continuing to use the current operation and maintenance solutions; SSCs operation and maintenance solutions also include optimizing the current operation and maintenance solutions, including preventive maintenance, predictive maintenance, status monitoring, inspection, and testing; And take measures to mitigate the environmental or operating conditions of SSCs; The SSCs operation and maintenance plan also includes making changes or modifications to the SSCs design; SSCs maintenance solutions also include replacement or refurbishment; SSCs operation and maintenance solutions also include SSCs operating to failure, applicable SSCs whose failures will not affect the safety or availability of the nuclear power plant; When SSCs fail, implement measures to replace SSCs or reduce the aging pressure on SSCs. Measures to reduce the aging stress of SSCs include reducing the environmental aging stress or operational aging stress of SSCs. Environmental aging stresses include temperature, radiation, humidity and corrosive chemicals; operational aging stresses include erosive flow and thermal cycling in pipelines.

7. The nuclear power plant SSCs life management method according to claim 1, characterized in that, Step six, economic evaluation of the SSCs lifecycle management plan, includes the following steps: Assess the economics of the developed SSCs life management program, and calculate the preventive maintenance cost, major replacement cost, expenditure, benefits and total expenditure of the SSCs life management program within the economic analysis time period; The costs of preventative maintenance and major replacements in the SSCs lifecycle management program are assessed based on historical work orders and maintenance procedures. The expenditure for the SSCs life management program equals the sum of the preventive maintenance costs and major replacement costs of the SSCs life management program, as well as the electricity revenue lost from implementing the SSCs life management program. The sum of electricity revenue lost from implementing the SSCs lifecycle management program is set based on nuclear power plant practices; The benefits of an SSCs lifecycle management plan are equal to the benefits of implementing an SSCs lifecycle management plan. Total expenditure of SSCs lifecycle management program = expenditure of SSCs lifecycle management program - benefits of SSCs lifecycle management program.

8. The method for life management of nuclear power plant SSCs according to claim 1, characterized in that, Step 7: Select the optimal SSCs lifecycle management plan, including the following steps: Taking into account the economics, reliability, and implementation difficulty of the SSCs life management plan, and combining the current operating status and expectations of the nuclear power plant, the focus is on maximizing the value of SSCs rather than minimizing maintenance costs, to determine the optimal SSCs life management plan.

9. The method for life management of nuclear power plant SSCs according to claim 1, characterized in that, Step nine, evaluation of the SSCs lifecycle management program effectiveness, includes the following steps: After the SSCs lifecycle management program is implemented, the health reports and operating history of the SSCs will be reviewed regularly to identify new device vulnerabilities that need to be addressed. If a major safety incident occurs during the implementation of the SSCs lifecycle management plan, the effectiveness of the SSCs lifecycle management plan will be evaluated at any time.

10. The method for life management of nuclear power plant SSCs according to claim 1, characterized in that, Step 10, SSCs lifecycle management plan optimization, including the following steps: Based on the implementation of the SSCs life management plan, the SSCs life management plan will be evaluated every five years, and a new life management plan will be developed. If a major safety incident occurs during the implementation of the SSCs life management plan, a new life management plan will be developed immediately.

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