Item quality management method of nuclear power plant

Abstract

The invention belongs to the technical field of nuclear safety, and particularly relates to a nuclear power plant item quality management method comprising the following steps: obtaining an input item list; identifying the type of each item on the item list by using a pre-trained probabilistic safety evaluation model of the nuclear power plant, and evaluating the risk guidance type safety level of the item; wherein the items of which the types and the risk guidance type security levels are identified are at least pre-modeled in a probabilistic security evaluation model; the risk guidance type security level comprises a security level and high security importance, a non-security level and high security importance, a security level and low security importance, and a non-security level and low security importance; and based on the type of the item, matching a corresponding quality management requirement from a quality management requirement database of the risk guidance type security level corresponding to the item, and managing and maintaining the item according to the quality management requirement. The safety of the nuclear power plant can be considered, objective economic benefits are brought, and safe, stable and continuous operation of the nuclear power plant is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear safety technology, and in particular relates to a method for managing the quality of items in a nuclear power plant. Background Art

[0002] Safety is the cornerstone of nuclear power, and nuclear safety depends on whether the structures, systems and equipment (i.e. items) that ensure the safety functions of nuclear power plants are highly reliable. In this regard, my country's nuclear safety regulations require that all nuclear power operating units and (or) designers must carry out safety classification of nuclear power plant items. Safety classification can divide nuclear power plant items into two categories: safety level and non-safety level. Traditional safety classification was generated and developed in the period when there was a lack of actual operation data of nuclear power plants. It usually focuses on accident types, release of radioactive materials and consequences, but there is less probabilistic analysis of different accident sequences. With the continuous accumulation of nuclear reactor operating years around the world, information and data related to actual transients, accidents and power plant item performance have gradually become rich. After using these data to carry out probabilistic safety assessment (PSA) of various accident sequences, risk insights show that the actual safety importance of some safety-level items in the traditional safety classification is not high, while some non-safety-level items have higher safety importance.

[0003] The traditional nuclear power plant item quality management method is based on the traditional safety classification, based on the principle of defense in depth, identifying items that perform safety functions, and dividing items into two categories: safety level and non-safety level according to the importance of their safety functions. Safety level items need to implement corresponding special processing requirements, including quality assurance, maintenance rules, reports, environmental assessment, seismic assessment, inspection and testing requirements. It can be seen that the traditional nuclear power plant item quality management method requirements are somewhat conservative, which will increase the management burden of some low-safety-level important safety equipment to a certain extent, and may also ignore the potential risks of some non-safety-level high-safety-level important equipment to the operation of nuclear power plants. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to establish a nuclear power plant item quality management method that is compatible with risk-guided safety classification, so as to more reasonably allocate limited resources to high-safety-important items on the basis of ensuring the safety of the nuclear power plant, thereby improving the economy of the nuclear power plant.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a method for item quality management of a nuclear power plant, comprising: obtaining an input item list; using a probabilistic safety assessment model pre-trained by the nuclear power plant to identify the type of each item on the item list, and assessing the risk-guided safety level of the item; wherein items of identified types and risk-guided safety levels are pre-modeled at least in the probabilistic safety assessment model; the risk-guided safety levels include: safety level and high safety importance, non-safety level and high safety importance, safety level and low safety importance, and non-safety level and low safety importance; based on the type of the item, matching corresponding quality management requirements from a quality management requirement database corresponding to the risk-guided safety level of the item, and managing and maintaining the item in accordance with the quality management requirements.

[0006] According to a specific embodiment of the present invention, before using the probabilistic safety assessment model to identify the type of item and the risk-guided safety level, it also includes: for the quality management requirements database of non-safety level and high safety importance / safety level and low safety importance, importing temporarily added quality management requirements to update the preset quality management requirements database.

[0007] According to a specific embodiment of the present invention, when the risk-informed safety level of the item is non-safety level and has high safety importance, based on the type of the item, the corresponding quality management requirements are matched from the quality management requirements database of the risk-informed safety level of the item, and the step of managing and maintaining the item according to the quality management requirements also includes: identifying the key attributes of the item, and evaluating the relevant factors to ensure that the item can maintain the key attributes; querying and supplementing the corresponding quality management requirements from the quality management requirements database of the risk-informed safety level according to the relevant factors for maintaining the key attributes of the item; integrating the matched and supplemented quality management requirements, and managing and maintaining the item in accordance with them.

[0008] According to a specific embodiment of the present invention, after integrating matching and supplementary quality management requirements, it also includes: adjusting the quality management requirements based on the critical failure modes and historical operation data of the item, so as to manage and maintain the item in accordance with the adjusted quality management requirements; wherein, the critical failure modes of the item are identified through the probabilistic safety assessment model.

[0009] According to a specific embodiment of the present invention, the step of evaluating relevant factors to ensure that the item can maintain key attributes includes: evaluating based on historical experience, performance, maintenance and operation of the item.

[0010] According to a specific embodiment of the present invention, when the risk-informed safety level of the item is the safety level and the safety importance is low, based on the type of the item, the corresponding quality management requirements are matched from the quality management requirements database corresponding to the risk-informed safety level of the item, and the step of managing and maintaining the item according to the quality management requirements also includes: traversing a pre-imported quality management requirement exemption table, identifying and querying the quality management requirements that need to be exempted for the item, so as to readjust the matched quality management requirements; and managing and maintaining the item according to the quality management requirements after the exemption.

[0011] According to a specific embodiment of the present invention, after identifying and querying the quality management requirements that need to be exempted corresponding to the item, it also includes: for each quality management requirement that needs to be exempted, judging whether to adopt an alternative with a relatively lower standard based on the quality management requirement exemption table: if so, adopting a general alternative to replace the general type of quality management requirements, or adopting a specific alternative to replace a specific type of quality management requirements; if not, directly exempting; wherein the specific type of quality management requirements is related to the type of the item.

[0012] According to a specific embodiment of the present invention, specific types of quality management requirements include: design and procurement, preventive maintenance, inspection and testing.

[0013] According to a specific embodiment of the present invention, the general alternative solution includes: special supervision and inspection activities, planned quality assurance activities, maintenance strategies, monitoring and reporting.

[0014] According to a specific embodiment of the present invention, the method for item quality management of a nuclear power plant according to claim 7 is characterized in that, after adopting an alternative solution to replace the quality management requirements that need to be exempted, it also includes: adjusting the quality management requirements based on the critical failure modes and historical operating data of the items, so as to manage and maintain the items in accordance with the adjusted quality management requirements; wherein, the critical failure modes of the items are identified by means of the probabilistic safety assessment model.

[0015] The present invention provides a method for nuclear power plant item quality management based on risk-guided technology, which combines the advantages of deterministic and probabilistic analysis methods, comprehensively considers the impact of various factors on nuclear power plants, and carries out risk-guided safety grading. According to the safety importance of items to nuclear power plants, on the basis of traditional deterministic grading, the safety level and non-safety level are further subdivided into two categories of high safety importance and low safety importance, respectively. The quality management requirements for low and medium safety importance items are reduced, and more resources are focused on high and medium safety importance items in the non-safety level. It can take into account the safety of nuclear power plants while bringing objective economic benefits, and ensure the safe, stable and continuous operation of nuclear power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flowchart of a specific embodiment of a method for managing item quality in a nuclear power plant provided by the present invention; Figure 2 A schematic flow chart of another specific embodiment of a method for managing item quality in a nuclear power plant provided by the present invention; Figure 3 A schematic diagram of a specific embodiment of the risk-guided security classification provided by the present invention; Figure 4 A schematic diagram of a specific embodiment of a nuclear power plant item quality management system provided by the present invention; Figure 5 The present invention provides a structural block diagram of a specific embodiment of an electronic device. DETAILED DESCRIPTION

[0017] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0019] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0021] First of all, it should be explained that in order to enable people in this technical field to better understand the present application scheme, the technical background of this application is explained accordingly.

[0022] The specific quality management of items can be referred to as follows: Seismic assessment refers to the seismic assessment, testing and specific engineering methods of equipment to detect the response performance of the equipment to earthquake conditions.

[0023] Environmental qualification is to ensure that the equipment continues to meet its functional requirements under the design reference conditions in order to test the equipment's response performance to all environmental conditions during its service life.

[0024] Local leakage rate test, that is, leakage test on equipment to ensure the sealing of the reactor containment building.

[0025] In-service testing is the testing of equipment’s pumps, valves or dampers to ensure that they meet their functional requirements.

[0026] In-service inspections are checks on the functional integrity of equipment’s tanks, containers, pumps, pipelines, etc.

[0027] Quality requirements include all necessary tests and certifications to ensure that the equipment operates well in a nuclear power plant. Tests and certifications related to the physical characteristics of materials, structures, equipment or systems are used to determine whether the equipment meets the predetermined requirements.

[0028] Reporting requirements and licensed event reporting require equipment to report major events, conditions, construction defects, etc. of nuclear power plants to the National Nuclear Safety Administration (NNSA).

[0029] Defect and non-conformity reporting, mandatory reporting of equipment failures and defects.

[0030] ASME (American Society of Mechanical Engineers) repair and replacement, which puts forward design, manufacturing and testing requirements for the repair or replacement of ASME equipment to ensure that the repair and replacement complies with the construction specification records.

[0031] The above is only part of the item quality management requirements, including but not limited to the above. It can be seen that when the equipment enters the nuclear power plant for the first time, it can be identified and tested in accordance with the above standards, or when the equipment is in storage or use, it can be managed and maintained in accordance with the above standards, etc. Based on the quality management requirements of the items, corresponding management strategies are implemented for different equipment to ensure the safety and economy of the nuclear power plant.

[0032] However, the traditional nuclear power plant item quality management method is based on the principle of defense in depth, identifies items that perform safety functions, and divides items into two categories: safety level and non-safety level according to the importance of their safety functions. The special handling requirements for safety level items exceed the requirements of normal commercial and industrial practices to provide reasonable assurance that the structures, systems and equipment of nuclear power plants can perform their design basis safety functions under design basis conditions. These special handling requirements include design considerations, identification, change control, documentation, reporting, maintenance, testing, monitoring and quality assurance, and the same is true for their item quality management requirements. However, the actual safety importance of some safety level items is not high, while some non-safety level items have higher safety importance. If the traditional item quality management method is still used, it will be difficult to use reasonable resources to effectively ensure the safety of nuclear power plants. For example, too much resources and energy are spent on some safety level items with low safety importance, while some non-safety level items with high safety importance are ignored, which will endanger the safety of nuclear power plants and even cause economic losses.

[0033] In this regard, this application combines the advantages of both deterministic and probabilistic analysis methods, comprehensively considers the impact of various factors on nuclear power plants, and carries out risk-guided safety grading. According to the safety importance of items to nuclear power plants, the safety level and non-safety level are further subdivided into two categories, high safety significance (HSS) and low safety significance (LSS), on the basis of traditional deterministic grading, in order to improve the economy of nuclear power plants and ensure their safe and stable operation.

[0034] Example 1 See also Figure 1 , a method for item quality management of a nuclear power plant as shown in 2, comprising: Step S100, obtaining an input list of items.

[0035] It is understandable that when a batch of items needs to be stored in a nuclear power plant, or when a batch of items in use in a nuclear power plant needs to be maintained, each item on the item list is identified and processed one by one according to the corresponding quality management requirements. In addition, in order to be different from the traditional two categories of safety-level and non-safety-level item quality management, the focus and resources of item quality management can be concentrated on truly important equipment, improving the safety of nuclear power plants and reducing management burdens.

[0036] In this regard, Figure 3As shown, this application is divided into four levels based on Risk-Informed Safety Classification (RISC), including: safety level and high safety importance (RISC-1), non-safety level and high safety importance (RISC-2), safety level and low safety importance (RISC-3), non-safety level and low safety importance (RISC-4), so as to divide the original safety level items into high safety importance and low safety importance, and also divide the non-safety level items into high safety importance and low safety importance. When performing quality management on safety level items, the quality management requirements for low safety importance can be appropriately lowered to focus on the quality management of high safety importance in non-safety level items.

[0037] Secondly, the original safety-level and non-safety-level items have already been formulated with corresponding quality management requirements. After the risk-based safety classification is divided into RISC-1, RISC-2, RISC-3, and RISC-4, RISC-1 and RISC-4 can continue to use the original standards, that is, RISC-1 still corresponds to the quality management requirements of the safety level, and RISC-4 corresponds to the quality management requirements of the non-safety level. However, due to the particularity of RISC-2 and RISC-3, it is necessary to appropriately lower the standards of the original quality management requirements for the safety-level and low-safety-level items, and to appropriately increase the standards of the original quality management requirements for the non-safety-level and high-safety-level items, so as to concentrate the focus of item quality management and corresponding resources on the truly important items. At the same time, it is understandable that the quality management requirements for different risk-based safety levels are not just one or two, or more than a dozen. Because there are a large number of different items to be faced, even if the items are of the same risk-based safety level, due to different types, the corresponding quality management requirements that need to be met will be different.

[0038] Therefore, the quality management requirements of RISC-2 can be appropriately supplemented on the basis of the original quality management requirements of the safety level. Similarly, the quality management requirements of RISC-3 are the same. They can be appropriately supplemented on the basis of the original quality management requirements of the non-safety level, so as to develop a database of quality management requirements for different risk-guided safety levels. Of course, the specific method of supplementation can be determined according to the actual situation. The standards, specifications, and requirements of different nuclear power plants are different, and the quality management requirements of the corresponding items will also be different. The operation and maintenance personnel can prepare the corresponding text in advance according to the operating conditions and historical experience of the nuclear power plant, so as to import it into the computer equipment in advance, so that the computer equipment can match the corresponding quality management requirements by identifying the risk-guided safety level of the item.

[0039] Specifically, in practical applications, since RISC-1 and RISC-3 are divided by security level, RISC-2 and RISC-4 are divided by non-security level, and the security level and non-security level have corresponding quality management requirements and form corresponding databases. Therefore, RISC-1 can continue to use the quality management requirements database of the security level, and RISC-4 can continue to use the quality management requirements database of the non-security level, and no corresponding adjustments are required. RISC-2 needs to use the quality management requirements temporarily introduced by the operation and maintenance personnel to update the original quality management requirements database of the security level to form a new database, and RISC-3 needs to use the quality management requirements temporarily introduced by the operation and maintenance personnel to update the original quality management requirements database of the non-security level to form a new database, so that different items can be configured according to the quality management requirements database corresponding to the four risk-guided security levels.

[0040] It should also be noted that the above specific description of how to configure the quality management requirements database for different risk-based safety levels is only a preferred solution, and there are no excessive restrictions on this. For example, the quality management requirements database for four risk-based safety levels can be re-established. At the same time, specific items for RISC-2 and RISC-3 are required. The corresponding quality management requirements database can be updated in real time according to actual conditions and needs. That is, after obtaining the list of items, it is necessary to identify whether the operation and maintenance personnel have synchronously imported the text content related to the quality management requirements to update the quality management requirements database for RISC-2 and RISC-3.

[0041] Step S200, using the probabilistic safety assessment model pre-trained by the nuclear power plant to identify the type of each item on the item list, and assess the risk-guided safety level of the item; wherein the items of the identified type and risk-guided safety level are pre-modeled in at least the probabilistic safety assessment model; the risk-guided safety levels include: safety level and high safety importance, non-safety level and high safety importance, safety level and low safety importance, and non-safety level and low safety importance.

[0042] Based on the above content, after obtaining the list of items and configuring the quality management requirements database of different risk-based safety levels, the probabilistic safety assessment model can be used to identify the type and risk-based safety level of each item on the list of items. Of course, the configuration of the quality management requirements database can also be performed simultaneously with the identification of item types and risk-based safety levels, and there are no excessive restrictions on this.

[0043] It is understandable that the probabilistic safety assessment model can be constructed using the historical experience data of nuclear power plants, such as statistics of a large number of items and their corresponding importance, etc. Moreover, since the probabilistic safety assessment model is constructed using historical experience data, the items that can be identified by the corresponding probabilistic safety assessment model have been pre-modeled, and the items that cannot be identified by the probabilistic safety assessment model may appear for the first time, and an immediate alarm response can be issued to remind the operation and maintenance personnel to make special treatments.

[0044] Step S300, based on the type of the item, matching corresponding quality management requirements from a quality management requirement database corresponding to the risk-based safety level of the item, and managing and maintaining the item according to the quality management requirements.

[0045] For each item on the item list, after identifying its corresponding type and risk-guided security level, the quality management requirements of the item can be intelligently matched from the corresponding quality management requirements database. It can be understood here that for RISC-1 and RISC-4 items, which are respectively important for high safety level and low safety level in non-safety level, the existing quality management requirements should be maintained, and no additional processing or action is required, and no existing quality management requirements need to be strengthened. Of course, the no need for additional processing or action mentioned here, and no need to strengthen the quality management requirements, means that the existing quality management requirements can ensure that the performance of RISC-1 and RISC-4 items is consistent with the assumed performance of the part that exceeds its design benchmark, that is, to ensure that the performance of the items can reach the expected goal. If it cannot be met, and because the quality management requirements of the above-mentioned matching items are the preliminary processing of computer equipment, the quality management requirements can be supplemented according to the relevant attributes of the items. In this embodiment, no excessive elaboration is made, and no excessive restrictions are made. The modifications and embellishments made to the embodiments of the present invention by those skilled in the art without departing from the spirit of the present invention still fall within the scope of the invention application of the present invention.

[0046] As for RISC-2 items, since they are non-safety-level medium-to-high safety-critical items, the original quality management requirements may not guarantee that their performance can meet the actual standards. Accordingly, it is necessary to appropriately increase the quality management requirements according to the key attributes of the items to ensure their safety-critical functions. Specifically, it is first necessary to determine the key attributes of the item that are classified as safety-critical, and evaluate the relevant factors on how to ensure that the item can maintain the key attributes. For example, the key attribute of a valve device is whether it opens and closes normally to ensure that gas or liquid can flow through the valve. Therefore, the quality management requirements of the valve should focus on how to keep it open and closed normally. Of course, the quality management requirements mentioned here are required to be configured for the special functions of valve-type items, while there are not too many restrictions on the general quality management requirements for some items. In this regard, the key attributes of the item are evaluated based on the historical experience, performance, maintenance and operation of the item, and the quality management requirements that can keep the item safe and important are queried from the RISC-2 quality management requirements database to fully supplement the original quality management requirements. The specific quality management requirements that can be supplemented include: replacing existing items that have performed poorly in their operation and maintenance history; strengthening the scope and / or frequency of preventive maintenance; performing regular tests or inspections to ensure the continued availability of items; performing quality or other inspections to ensure the adequacy of the work performed and the usable status of the items; etc.

[0047] It can be seen that although RISC-2 items are still non-safety-level items and do not need to take safety-level regulatory control measures to manage and maintain them, their key attributes can be maintained by fully formulating their corresponding quality management requirements to ensure their important safety functions. In a specific embodiment, RISC-2 items can be equipment such as instrument air compressors, filters and storage tanks, main feed water regulating valves and bypass valves, fire HVAC, dampers, auxiliary diesel engines, etc. Of course, there are no excessive restrictions on this. Different nuclear power plants may have different regulatory requirements, and the risk-guided safety level of the items can be formulated accordingly according to the actual situation. Based on the preliminary matching quality management requirements and the subsequent supplementary quality management requirements, the final results are fed back to the operation and maintenance personnel so that they can manage and maintain the items in accordance with the corresponding quality management requirements.

[0048] For RISC-3 items, it is still necessary to ensure that they can perform safety-related functions under design basis conditions throughout their life cycle, and to formulate inspection, test and corrective measures. However, since they are of low safety importance, some unnecessary quality management requirements can be fully or partially exempted from existing quality management requirements after fully proving that their design basis functions can be performed.

[0049] The specific quality management requirements that can be exempted for RISC-3 items are as follows: nuclear quality assurance requirements, defect reporting requirements, tests for environmental identification, documentation and margin requirements, some requirements of ASME and IEEE (Institutions of Electrical and Electronics Engineers) specifications and standards, maintenance rule requirements, licensed event reporting requirements, reactor containment leakage test requirements, seismic identification tests and specific engineering method requirements, etc. Of course, in actual application, corresponding adjustments can be made according to actual conditions. The above content is for reference only.

[0050] Furthermore, it is also possible to determine which contents of the exempted quality management requirements can ensure that RISC-3 items can perform their designed baseline functions, and then formulate appropriate alternative processing plans for these contents to lower the standards of the original quality management requirements. To this end, the first thing is to determine the quality management requirements that the items can be exempted from, and secondly, to determine whether alternative solutions are needed for the exempted quality management requirements. Specifically, in actual applications, operation and maintenance personnel can pre-prepare relevant table data of the quality management requirements that different items in RISC-3 items can be exempted from, and import them into computer equipment in advance. The corresponding computer equipment can traverse the table data to query the quality management requirements that an item can be exempted from, and check from the table whether there is an alternative to the quality management requirement. If so, the alternative is used to replace the quality management requirement. If not, the quality management requirement is directly exempted, thereby adjusting the quality management requirements that are initially matched. The alternative solutions for some quality management requirements can be referred to the following table, Table 1

[0051] In addition, since there are general types of quality management requirements in the quality management requirements, which are not related to the type or function of the item, and can be replaced by general alternatives accordingly, and there are specific types of quality management requirements, which are related to the type of the item, and can be replaced by specific alternatives accordingly. It can be understood here that general types of quality management requirements can be applied to different items of the same risk-informed safety level, while specific types of quality management requirements are related to the type of the item, that is, they are formulated according to the specific functions of the item.

[0052] Therefore, some common alternatives for common types of quality management requirements include: dedicated supervision and inspection activities, planned quality assurance activities, maintenance strategies, monitoring and reporting, etc.

[0053] Specifically, the regulatory supervision and inspection measures and activities for RISC-3 items are no longer carried out in accordance with the regulatory requirements determined by their original safety requirements. NPPs should modify some of the corresponding procedures to confirm the relevant regulatory requirements that RISC-3 items no longer need to comply with.

[0054] Planned quality assurance activities include: design control, that is, control measures must be developed and documented to ensure that the relevant design requirements (such as the requirements of the national nuclear safety department, design basis, specifications and standards, etc.) are correctly reflected in the technical specifications, drawings, procedures or details. Design control measures must also include clauses to ensure that appropriate quality standards are specified and described in the design documents. Changes and deviations from the specified design requirements and quality standards must be controlled. Measures must also be specified to select any materials, parts, equipment and processes that play an important role in the function of the structure, system or equipment and review their applicability; corresponding possible alternatives: the applicability of RISC-3 items can be evaluated and implemented for the design standard requirements of non-nuclear industries, that is, more relaxed design standard requirements can be selected for RISC-3 items. Procurement control, that is, measures must be developed and documented to ensure that the relevant requirements, design basis, standards, technical specifications of the national nuclear safety department and other requirements necessary to ensure quality are included or referenced in the documents for purchasing items and services; corresponding possible alternatives: alternative clauses for quality and design requirements can be appropriately used. Control of non-conforming items means that some measures must be formulated to control items that do not meet the requirements to prevent misuse or misinstallation. In order to ensure the control of non-conforming items, non-conforming items must be identified by marking, labeling or physical separation when practicable. Measures to control the next process, delivery or installation must be formulated, documented and implemented for non-conforming items or defective items. Corresponding possible alternatives: more flexible ways to ensure equipment quality and reliability, including inspection or testing at delivery, quality plan measures and documentation, source inspection, historical performance evaluation, etc.

[0055] The repair, installation, replacement and post-repair testing and inspection of RISC-3 items no longer need to meet regulatory requirements or specifications and can be determined by the nuclear power plant. For RISC-3 items, nuclear power plants can appropriately use the processes and procedures for handling non-safety-level items.

[0056] For RISC-3 items, only the corrective action process is required to be determined, and no additional monitoring and reporting is required. When a RISC-3 item does not meet its design baseline functional performance standards, that is, a RISC-3 item has non-conformity or defects, corrective actions should be taken in a timely manner. For the continued implementation of the same corrective action requirements as RISC-1 items; formulate alternative corrective action requirements that apply only to RISC-3 items. For example, the threshold for entering the corrective action procedure can be different, or the time for taking corrective actions RISC-3 items have the following corrective measures: can be extended.

[0057] Specific treatments can be performed for specific types of quality management requirements, including: design and procurement of items, preventive maintenance, inspection and testing. For specific types of RISC-3 items, the alternatives for specific items are optimized based on a comprehensive comparison of the implementation costs of existing items and the costs of alternative treatments. For example, the existing costs of design and procurement, including material costs, replacement cycles, inventory, waste, taxes, etc., can be determined through maintenance plans and organizations responsible for procurement and supply chains. For the optimization of regular inspections and tests, the focus is on activities that can be reduced, alternative activities with lower costs, and other existing activities, and their cost components include test plan costs, labor costs, etc.

[0058] Specifically, for RISC-3 items, their specific alternative processing needs to be incorporated into existing processes for control, including design change processes, procurement processes, preventive maintenance processes, planning and maintenance processes, work control processes, and corrective action processes, to ensure that the items perform their design basis safety functions throughout their service life.

[0059] For the design and procurement of RISC-3 items, suppliers with ISO 9000 quality system certification or other system certification that can replace the nuclear quality assurance system can be selected. Suppliers should have the ability to manufacture and test items using non-nuclear industry specifications and standards.

[0060] If the commercial-grade items used for replacement have differences or new technologies compared to the original items, the design properties of the original items (such as pressure, temperature, flow, voltage, size, seismic conditions and environmental conditions, etc.) should be evaluated to determine the properties that the items must meet, and further evaluate the differences in the design properties of the new equipment. For RISC-3 items, it must be demonstrated that they can still perform safety functions under seismic conditions and environmental conditions to provide reasonable confidence.

[0061] For seismic conditions, alternatives to RISC-3 specific items include: applying the guideline EPRI 1011783 for seismic qualification assessment; using credible industry experience and analysis instead of seismic qualification tests; undergoing seismic certification or qualification tests conducted by standardization organizations and / or product certification bodies that are qualified to certify or qualify equipment for other critical infrastructure applications; the alternative equipment used has reliable and stable characteristics, especially equipment used under high-acceleration earthquakes, which has been verified to have performance under conditions exceeding the seismic design requirements of the power plant; and using documented calculation methods and results to verify seismic design.

[0062] Similarly, for environmental conditions, alternatives for RISC-3 specific categories of items include: applying guidance EPRI 1009748 to conduct environmental qualification assessments; applying industry experience to replace maintenance qualification documents and files; operating the equipment in an environment similar to that expected during a design basis accident, but without formal equipment qualification; extending the qualified service life of the equipment based on operating experience; using equipment specifically designed for environmental conditions, and verifying its performance under conditions that meet or exceed the requirements of the environmental conditions; and using documented calculation methods and results to demonstrate its design qualification.

[0063] For inspection and testing, RISC-3 alternatives for specific categories of items include: Inspection: operator inspection, maintenance, chemical or engineering department inspection; containment final inspection, pressure test after maintenance, system water filling and exhaust, in-service leak detection under normal operating conditions, weld non-destructive testing, internal surface inspection instrument inspection, eddy current, license extension inspection, etc.

[0064] Power plant operation: normal system operation, valve travel, system flow; switching train and equipment operation, circuit breaker cycle; boundary integrity, system commissioning verification; Power plant monitoring: key system parameters, system alarms, pump response after startup (time to reach maximum pressure, flow, etc.), pit level, radiation monitoring; remote monitoring of the power plant; review of system parameters and trends, review of operator inspection data trends; use of field corrective action plans to identify equipment problems; Testing: monitoring testing and data review; previously used IST instructions; integrated safety measures testing; Maintenance activities: electrical continuity check, relay operation, circuit breaker preventive maintenance, dielectric strength test, contact grinding, circuit breaker replacement, rotor coil test, motor current surge test, etc.; equipment modification, preventive maintenance, oil test, vibration data collection, temperature recording, pneumatic valve and electric valve dynamic test, actuator setting value; logic test, time response test, loop calibration and action; maintenance strategy.

[0065] In a specific embodiment, for electrical cabinets (distribution cabinets) in nuclear power plants, if they still need to be classified into safety level according to the safety level and non-safety level classification, they need to be correspondingly classified according to the mandatory provisions of national laws and regulations such as "Nuclear Power Plant Design Safety Regulations", "General Safety Principles for Nuclear Power Plant Design", and "Nuclear Power Earthquake Resistance Appraisal Test Guidelines", and in accordance with the "Quality Appraisal Test Methods and Environmental Conditions for Safety-Grade Electrical Equipment in Nuclear Power Plants", "Earthquake Resistance Appraisal of Safety-Grade Electrical Equipment in Nuclear Power Plants", "Appraisal of Safety-Grade Electrical Equipment in Nuclear Power Plants" and other guidelines to conduct environmental appraisal and seismic resistance appraisal of safety-grade electrical cabinets, and only after the appraisal is passed will it be considered that this item is capable of completing the functions required by the nuclear power plant under hypothetical harsh conditions. In this embodiment, the nuclear power plant can be classified as RISC-3 according to its actual situation, and the electrical cabinet can be exempted from the mandatory requirements of the above national regulations, that is, it is not necessary to conduct seismic identification and environmental identification, cancel the quality management requirement of "nuclear power plants must use safety-grade electrical cabinets that have passed environmental identification and seismic identification", and the item can be proved to be able to complete the functions required by the nuclear power plant under hypothetical harsh conditions by using historical experience, peer experience, or ordinary commercial tests of lower standards. For example, the failure mode of the relay disconnection failure of the electrical cabinet under ground vibration environment contributes the most to the impact on nuclear safety, so the problem of the failure of the electrical cabinet in earthquake operation should be focused on, and the established alternative solution needs to reasonably prove that the safety-grade electrical cabinet can still maintain its performance under earthquake conditions, including: selecting a lower test standard, only needing to meet the general standards of non-nuclear industries for test verification; using the relevant experience of peers, the same item has maintained good performance in other industries in the region after several years, which proves that it is fully capable of being used in nuclear power plants.

[0066] In summary, by replacing the quality management requirements that can be exempted for items with some alternatives, or directly exempting them, the original quality management requirements can be lowered to focus attention and nuclear power plant resources on the quality management of RISC-2 items. Based on partial exemptions of the quality management requirements for preliminary matching, and the adoption of alternatives, the final results will be fed back to the operation and maintenance personnel so that they can manage and maintain the items in accordance with the corresponding quality management requirements.

[0067] In addition, it should be added that for the quality management requirements of RISC-2 and RISC-3 configuration, the quality management requirements can be further adjusted according to the failure mode of the item. For example, the failure of a key function of an item will have a huge impact on its application contribution in the nuclear power plant, and the standards for the relevant quality management requirements need to be strengthened accordingly. In this regard, the adjustment direction and requirements of different failure modes of items can still be integrated through the historical experience data of nuclear power plants, so that after the RISC-2 supplements the quality management requirements and after the RISC-3 is exempted from the quality management requirements, further adjustments can be made to make the quality management requirements of RISC-2 and RISC-3 items closer to actual applications, so as to ensure the safe and stable operation of nuclear power plants. Among them, the probabilistic safety assessment model can still be used to identify the key failure modes of items, and the probabilistic safety assessment model can be constructed by statistically analyzing the historical experience, performance, maintenance and operation of the items.

[0068] It should be noted that the original quality management requirements mentioned above specifically refer to the quality management requirements that are initially matched by computer equipment according to the type of item and the risk-based safety level. The quality management requirements are further adjusted to better adapt to the current item type, key failure mode and other specific attributes of the item. In addition, it should be explained that since the stable operation of a nuclear power plant requires a large number of staff to work together, there will be departments with different functions. Therefore, the quality management requirements for different risk-based safety levels and the alternative plans for exemption can be prepared in advance by the operation and maintenance personnel of the safety-related departments. When the operation and maintenance personnel of the maintenance department or the inspection department and other related departments input the item list into the computer equipment, the computer equipment can configure the quality management requirements for each item in the item list and provide visual display, so as to manage and maintain the items according to the corresponding quality management requirements.

[0069] It should be noted that the step division of the above methods is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they contain the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0070] Example 2 See also Figure 4 As shown, this implementation also provides an item quality management system for a nuclear power plant, including: The data receiving module 10 is used to obtain an input list of items.

[0071] The item identification module 20 is used to use the probabilistic safety assessment model pre-trained by the nuclear power plant to identify the type of each item on the item list and assess the risk-guided safety level of the item; wherein the items of the identified type and risk-guided safety level are pre-modeled at least in the probabilistic safety assessment model; the risk-guided safety levels include: safety level and high safety importance, non-safety level and high safety importance, safety level and low safety importance, and non-safety level and low safety importance.

[0072] The result feedback module 30 is used to match the corresponding quality management requirements from the quality management requirements database corresponding to the risk-oriented safety level of the item based on the type of the item, and manage and maintain the item according to the quality management requirements.

[0073] It should be noted that the item quality management system for a nuclear power plant provided in the above embodiment and the item quality management method for a nuclear power plant provided in the above embodiment 1 belong to the same concept, wherein the specific manner in which each module and unit performs operations has been described in detail in the method embodiment, and will not be repeated here. In practical applications, the item quality management assessment method for a nuclear power plant provided in the above embodiment 1 can allocate the above functions to different functional modules as needed, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0074] Example 3 See also Figure 5 As shown, an embodiment of the present application further provides an electronic device, comprising a memory 2, a processor 1, and a program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the program.

[0075] Among them, the memory includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example: SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of the electronic device, such as a mobile hard disk of the electronic device. In other embodiments, the memory can also be an external storage device of the electronic device, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Further, the memory can also include both an internal storage unit of the electronic device and an external storage device. The memory can not only be used to store application software and various types of data installed in the electronic device, but also can be used to temporarily store data that has been output or is to be output.

[0076] In some embodiments, the processor may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and a combination of various control chips. The processor is the control core (Control Unit) of the electronic device, which connects the various components of the entire electronic device using various interfaces and lines, and executes various functions of the electronic device and processes data by running or executing programs or modules stored in the memory, and calling data stored in the memory.

[0077] The processor executes the operating system of the electronic device and various installed application programs. The processor executes the application programs to implement the steps in the above method embodiment.

[0078] Exemplarily, the program may be divided into one or more modules, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules may be a series of program instruction segments capable of completing specific functions, which are used to describe the execution process of the program in the electronic device.

[0079] The above-mentioned integrated unit implemented in the form of software function modules can be stored in a computer-readable storage medium. The above-mentioned software function modules are stored in a storage medium and include several instructions for enabling a computer device (which can be a personal computer, a computer device, or a network device, etc.) or a processor to perform part of the functions of various embodiments of the present invention.

[0080] In summary, the present invention provides a method for quality management of nuclear power plant items based on risk-guided technology, which combines the advantages of deterministic and probabilistic analysis methods, comprehensively considers the impact of various factors on nuclear power plants, and carries out risk-guided safety grading. According to the safety importance of items to nuclear power plants, on the basis of traditional deterministic grading, the safety level and non-safety level are further subdivided into two categories of high safety importance and low safety importance, respectively. The quality management requirements for low and medium safety importance items are reduced, and more resources are focused on high and medium safety importance items in the non-safety level. It can take into account the safety of nuclear power plants while bringing objective economic benefits, and ensure the safe, stable and continuous operation of nuclear power plants.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for item quality management of a nuclear power plant, characterized in that: include: Get the list of items entered; The type of each item on the item list is identified by using a probabilistic safety assessment model pre-trained by the nuclear power plant, and the risk-guided safety level of the item is assessed; wherein the items of the identified type and risk-guided safety level are pre-modeled at least in the probabilistic safety assessment model; the risk-guided safety levels include: safety level and high safety importance, non-safety level and high safety importance, safety level and low safety importance, non-safety level and low safety importance; Based on the type of the item, the corresponding quality management requirements are matched from a quality management requirements database corresponding to the risk-guided safety level of the item, and the item is managed and maintained according to the quality management requirements.

2. The method for item quality management of a nuclear power plant according to claim 1, characterized in that: Before using the probabilistic safety assessment model to identify the type and risk-informed safety level of an item, it also includes: For the quality management requirement database of non-safety level and high safety importance / safety level and low safety importance, temporarily added quality management requirements are imported to update the preset quality management requirement database.

3. The item quality management method for a nuclear power plant according to claim 1, characterized in that: When the risk-based safety level of the item is non-safety level and high safety importance, Based on the type of the item, the step of matching the corresponding quality management requirements from a quality management requirements database corresponding to the risk-based safety level of the item, and managing and maintaining the item according to the quality management requirements also includes: Identify the key attributes of the item and assess the factors relevant to ensure that the item maintains the key attributes; According to the relevant factors of maintaining the key attributes of the item, query and supplement the corresponding quality management requirements from the quality management requirements database of the corresponding risk-based safety level; Integrate matching and complementary quality management requirements and manage and maintain the items in accordance with them.

4. The method for item quality management of a nuclear power plant according to claim 3, characterized in that: After integrating matching and complementary quality management requirements, this also includes: Adjust the quality management requirements according to the critical failure modes and historical operation data of the items, so as to manage and maintain the items in accordance with the adjusted quality management requirements; Wherein, the critical failure mode of the item is identified through the probabilistic safety assessment model.

5. The method for item quality management of a nuclear power plant according to claim 3, characterized in that: The steps to assess factors relevant to ensuring that the item in question maintains its critical attributes include: The assessment is based on historical experience, performance, maintenance and operation of the item in question.

6. The method for item quality management of a nuclear power plant according to claim 1, characterized in that: When the risk-based safety level of the item is safety level and low safety importance, Based on the type of the item, the step of matching the corresponding quality management requirements from a quality management requirements database corresponding to the risk-based safety level of the item, and managing and maintaining the item according to the quality management requirements also includes: Traverse the pre-imported quality management requirement exemption table, identify and query the quality management requirements that need to be exempted for the item, and readjust the matching quality management requirements; The items mentioned shall be managed and maintained in accordance with the quality management requirements after exemption.

7. The method for item quality management of a nuclear power plant according to claim 6, characterized in that: After identifying and querying the quality management requirements that need to be exempted for the items in question, it also includes: For each quality management requirement that needs to be exempted, determine whether to adopt an alternative with a relatively lower standard based on the quality management requirement exemption table: If so, a general alternative is used to replace a general type of quality management requirement, or a specific alternative is used to replace a specific type of quality management requirement; If not, then it will be exempted directly; Among other things, the specific type of quality management requirement is related to the type of item in question.

8. The method for item quality management of a nuclear power plant according to claim 7, characterized in that: Specific types of quality management requirements include: design and procurement, preventive maintenance, inspection and testing.

9. The method for item quality management of a nuclear power plant according to claim 7, characterized in that: The generic alternatives described include: dedicated surveillance and inspection activities, planned quality assurance activities, maintenance strategies, monitoring and reporting.

10. The method for item quality management of a nuclear power plant according to claim 7, characterized in that: After adopting alternative solutions to replace the quality management requirements that need to be exempted, it also includes: Adjust the quality management requirements according to the critical failure modes and historical operation data of the items, so as to manage and maintain the items in accordance with the adjusted quality management requirements; Wherein, the critical failure mode of the item is identified through the probabilistic safety assessment model.

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