A method and apparatus for screening and evaluating low risk items in a nuclear power plant

Abstract

This invention relates to the field of nuclear power plant risk assessment technology, and particularly to a method and equipment for screening and evaluating low-risk items in nuclear power plants. A method for screening and evaluating low-risk items in nuclear power plants includes: determining whether the item to be changed can be modeled using a PSA model; if so, using a funnel-shaped hierarchical screening mechanism to screen the item to be changed, obtaining screened items; performing safety analysis on the screened items to obtain specific parameters; using a PSA model based on the specific parameters to calculate the risk magnitude of the screened items, obtaining risk data; determining whether the risk data meets a preset risk threshold requirement to obtain the screening result; and determining the necessity of taking risk management actions based on the category of the screened items and formulating performance monitoring strategies after implementing the screened items. This invention simplifies the screening process for low-risk items, improves the execution efficiency of items to be changed in actual operation, and enhances the safety and economy of the execution process of items to be changed.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant risk assessment technology, and in particular to a method and equipment for screening and evaluating low-risk items in nuclear power plants. Background Technology

[0002] Currently, risk-guided technical evaluation methods that combine deterministic and probabilistic safety analysis have been applied in multiple fields in my country's nuclear power industry. Relatively mature application optimization and demonstration systems include risk-guided technical specification optimization, risk-guided periodic test optimization, risk-guided in-service inspection optimization, and risk-guided safety classification.

[0003] However, the demonstration process for each risk-guided optimization is complex and highly independent. For example, my country's Nuclear Safety Administration has issued nuclear safety translations for guiding the application of risk-guided technologies in technical specifications and in-service pipeline inspections. As other related application areas continue to expand, there will be a lack of unified guidelines for management and optimization. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to improve the efficiency of screening low-risk items, and to provide a method and equipment for screening and evaluating low-risk items in nuclear power plants.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for screening and evaluating low-risk events in nuclear power plants, comprising the following steps: S10: Determine whether the items to be changed can be modeled using the PSA model; S20: If so, the funnel-shaped hierarchical screening mechanism is used to screen the items to be changed to obtain the screened items; S30: Perform a security analysis on the selected items to obtain specific parameters; S40: Calculate the risk level of the screened item using the PSA model based on the specific parameters to obtain risk data; S50: Determine whether the risk data meets the preset risk threshold requirements to obtain the screening results; S60: Determine the necessity of taking risk management actions based on the categories of the screened items and formulate a performance monitoring strategy after implementing the screened items.

[0006] Optionally, S10 includes: Determine whether the items to be changed are timely actions to ensure the safe operation of the unit and timely maintenance required to ensure the unit continues to generate electricity; If not, determine whether the matter to be changed can be modeled using the PSA model.

[0007] Optionally, S20 includes: The funnel-shaped hierarchical screening mechanism is used to screen the items to be changed through at least two sets of preset general security questions to obtain the screened items.

[0008] Optionally, S30 includes: Obtain the filtering record of the filtering item in S20; Using a consensus decision-making process, the screening items are qualitatively and / or quantitatively evaluated based on the screening records to obtain evaluation results; The specific parameters in the corresponding PSA model are adjusted based on the feedback from the evaluation results.

[0009] Optionally, the risk data includes incremental risk data and cumulative risk data; S40 includes: The risk level of the screened item is calculated using the PSA model based on the specific parameters, thereby obtaining the risk increment data and the cumulative risk data.

[0010] Optionally, the risk increment data includes: the increment of core damage frequency and the increment of the frequency of large early radioactive releases; The cumulative risk data includes: the cumulative core damage frequency and the cumulative frequency of large-scale early radioactive releases after the power plant baseline risk is superimposed with the risk increment data of the screened items.

[0011] Optionally, the risk data includes incremental risk data and cumulative risk data; The S50 includes: Determine whether the risk increment data is less than a preset risk increment threshold; If so, calculate the cumulative risk data for the selected items; If the cumulative risk data is less than the preset cumulative risk threshold, then the item to be changed corresponding to the risk data will be used as the filtering result.

[0012] Optionally, S60 includes: Based on the category of the screened items and the risk data, determine whether risk management actions are required when the item to be changed is executed; if not, execute the item to be changed directly.

[0013] Optionally, S60 further includes: The performance monitoring strategy is formulated after the screening criteria are implemented.

[0014] The present invention also provides a computer device, including a memory and a processor; the memory stores a computer program. The processor executes the steps of the screening and evaluation method for low-risk events in nuclear power plants as described above by calling the computer program stored in the memory.

[0015] The implementation of this invention has the following beneficial effects: This invention determines whether items to be changed can be modeled using a PSA model and whether they are screened using a funnel-style hierarchical screening mechanism. It identifies items that can be judged as low-risk simply by screening for problems and risk data. Simultaneously, it simplifies PSA calculation requirements to some extent, thereby improving the efficiency of the PSA model in calculating risk data. Therefore, it simplifies the screening and evaluation process for low-risk items, improves the execution efficiency of items to be changed in actual operation, and enhances the safety and economy of the execution process. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart of a method for screening and evaluating low-risk items at a nuclear power plant, as illustrated in one embodiment. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0018] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0019] This invention provides a method for screening and evaluating low-risk events in nuclear power plants, such as... Figure 1 As shown, it includes the following steps: S10: Determine whether the items to be changed can be modeled using the PSA model.

[0020] If the issue to be changed can be modeled using a PSA model, it means that the issue can be analyzed and evaluated quantitatively. At this point, the PSA model can be further constructed or modified, collecting data related to the issue, such as equipment reliability data and the frequency of initiating events. This data is then input into the PSA model to accurately simulate the various consequences and risks that the issue may produce. Through the calculation and analysis of the PSA model, the specific impact and risk magnitude of the issue to be changed on the nuclear power plant's safety system and operational performance can be determined.

[0021] S20: If so, the funnel-shaped hierarchical screening mechanism is used to screen the items to be changed, and the screened items are obtained.

[0022] If it is confirmed that the items to be changed can be modeled using the PSA model, a pre-set funnel-shaped hierarchical screening mechanism is activated to systematically screen all items to be changed at multiple levels. This mechanism first performs preliminary classification based on the priority and scope of impact of the items, screening out potentially low-risk items to be changed, thereby improving the efficiency of security assessment for items to be changed.

[0023] S30: Perform a security analysis on the selected items to obtain specific parameters.

[0024] When conducting security analysis on the selected items, it is necessary to proceed from multiple dimensions.

[0025] Simultaneously, the impact of the screening process on nuclear power plant personnel safety and operational procedures must be considered. An assessment should be conducted to determine whether this will increase the workload of operators, whether adjustments to operational procedures are necessary, and the potential risks associated with such adjustments. Through simulation and analysis of personnel operations, the likelihood and consequences of human error after the changes should be identified.

[0026] Other indirect or related impacts also need to be identified, including potential effects on multiple specific functions or other aspects of the power plant, such as equipment reliability, power plant safety systems and mitigation functions, to ensure that no potential risks are left out of the assessment.

[0027] After completing a comprehensive safety analysis, specific parameters of the PSA model are determined based on the analysis results. These parameters include, but are not limited to, correction values ​​for the frequency of initiating events and quantification values ​​for the severity of accident sequence consequences. For factors identified in the safety analysis as having a significant impact on nuclear power plant safety, the corresponding parameters in the PSA model are adjusted accordingly to more accurately reflect the actual risk situation. The determination of specific parameters requires rigorous review and verification to ensure their accuracy and reliability, thereby providing a solid foundation for the subsequent screening and evaluation of low-risk change items for nuclear power plants.

[0028] S40: Calculate the risk level of the screened items based on specific parameters using the PSA model to obtain risk data.

[0029] Before conducting risk calculations, risk analysts can clearly define the affected "SSCs," "personnel actions," and "accident sequences" that need to be included in the PSA model modification through a detailed definition and relevant analysis of the matter to be changed. Furthermore, the data inputs to the PSA model must use "verified baseline data" (such as equipment failure probability, personnel reliability, etc.), avoiding the use of data that has not been peer-reviewed. If the matter involves new equipment or processes, "industry experience data" or "verified data provided by the vendor" should be used as inputs. Simultaneously, it is necessary to assess not only the direct impact of the matter to be changed but also other indirect or related impacts, including potential effects on specific safety functions or other aspects of the power plant, ensuring that no potential risks are missed in the assessment. After the risk analysts modify the PSA model, they should calculate the risk increments of core damage frequency and the frequency of large-scale early radioactive releases affected by the matter to be changed, and keep detailed records to ensure the calculation process is reproducible, including input parameters, model modifications, and calculation steps.

[0030] S50: Determine whether the risk data meets the preset risk threshold requirements to obtain the screening results.

[0031] The system employs risk data to perform a detailed characterization of the security impact of the proposed changes. If the calculated risk of the proposed changes exceeds a preset risk threshold, it cannot be used for security assessment within this evaluation system. However, if the risk slightly exceeds the preset risk threshold, and there is evidence to suggest that this is due to an overly conservative analysis, it can still be used for screening and evaluation after further review and confirmation.

[0032] S60: Determine the necessity of taking risk management actions based on the category of the screened items and develop performance monitoring strategies after implementing the screened items.

[0033] Based on the category and specific characteristics of the screened items, determine whether corresponding risk management actions are indeed necessary, as well as the scope and depth of these actions. At the same time, after implementing the screened items, it is necessary to clearly formulate and implement corresponding performance monitoring strategies to ensure continuous tracking and evaluation of relevant processes and results, so as to ensure the effectiveness of risk management measures and the stable operation of relevant systems and equipment.

[0034] This invention, based on the modeling of items to be changed using the PSA model, employs a funnel-shaped hierarchical screening mechanism to filter items. Only those items that pass the screening undergo limited risk data calculation, thereby improving the efficiency of the PSA model in calculating risk data. The screening results are then determined by judging whether the risk data meets preset risk threshold requirements. Furthermore, this simplifies the evaluation process for low-risk items, improves the execution efficiency of items to be changed in actual operation, and enhances the safety, economy, and reliability of the execution process.

[0035] In some executable embodiments, S10 includes: Determine whether the items to be changed are timely actions to ensure the safe operation of the unit and timely maintenance required to ensure the unit continues to generate electricity.

[0036] If the matter to be changed falls under one of the two categories of actions mentioned above, then the method of the present invention cannot be used for risk screening.

[0037] If not, determine whether the items to be changed can be modeled using the PSA model.

[0038] If the items to be changed cannot be modeled using the PSA model, further analysis is needed to determine if there are other alternative assessment methods.

[0039] Furthermore, the power plant must have established a comprehensive decision-making team whose members play a decisive role in the safety analysis and final decision-making regarding the matters to be changed. If the power plant has implemented technical systems such as risk management-based technical specifications, monitoring frequency control outlines, and risk-guided safety classification, its comprehensive decision-making team can be considered equivalent to the decision-making team for this evaluation system. The professional backgrounds of the members of the comprehensive decision-making team should cover the main functional elements of the industry and regulatory processes to ensure that team members have a detailed understanding of the safety impact of the matters to be changed and are familiar with the application guidelines and methods of the characteristic evaluation process for the safety impact caused by the matters. The team can also call upon experts from other fields or external consultants in real time as needed to assist in the safety impact analysis of the matters to be changed. Generally, there should be at least five experts as members of the comprehensive decision-making team, and one member should be designated as the principal person in charge. They should each have professional backgrounds in one or more of the following areas: power plant operation, power plant design and systems engineering, safety analysis, risk-guided comprehensive decision assessment, and license application.

[0040] In some executable embodiments, S20 includes: A funnel-shaped hierarchical screening mechanism is adopted to screen items to be changed through at least two sets of preset general security questions, thereby obtaining the screened items.

[0041] This invention utilizes a funnel-shaped hierarchical screening mechanism to assess the security impact of a matter through at least two sets of preset general security questions. In some scenarios, there are two sets of preset general security questions. Matters requiring modification that fail to pass the first set of preset general security questions proceed to the second set for screening. Furthermore, any potential uncertainties discovered during the modeling process should have their sources detailed and their potential impact on the overall risk assessment evaluated to ensure the scientific validity and reliability of the final conclusions.

[0042] In one embodiment, the first set of preset general security questions mainly includes the following questions: Does it have any impact on the frequency of the initiating event or lead to new initiating events? Does it have any impact on the reliability or availability of structures, systems, and components (SSCs) or personnel used to mitigate the effects of power plant transients, accidents, or disasters? Does it have any impact on the consequences of the accident sequence? Does it have any effect on the fission product barrier capability? Does this have any impact on the power plant's defense-in-depth capabilities or security margins? The analysis of relevant impacts primarily covers key considerations such as the initiating event, equipment and personnel reliability, response to accident sequence consequences, fission product barrier capabilities, and the power plant's defense-in-depth capabilities and safety margins. Although the answers to the above questions are only "yes" or "no," all responses must be detailed for review by the subsequent integrated decision-making team. In the initial assessment of the safety impact of the proposed change, the direct and potential impacts should be described as comprehensively as possible using operational experience and engineering judgment. If any question is answered "yes," the corresponding impact should be discussed as beneficial or detrimental. For negative impacts, the adverse factors must be identified to facilitate the generation of specific parameters and the completion of quantitative risk calculations.

[0043] The first screening criteria based on the first set of preset general security questions can be determined as "no security impact" or "favorable security impact".

[0044] In one embodiment, the second set of preset general security questions assesses whether the adverse effects of the event are minor by answering final security impact screening questions. Part of this assessment can be performed concurrently with PSA model calculations, as relevant risk analysis information is needed to support the answers to the questions in this step. The main questions include: (1) Does it cause the frequency of the initiating event to exceed the minimum limit or cause a new initiating event? (2) Does it adversely affect the reliability and availability of SSCs or personnel used to mitigate the impact of power plant transients, accidents or disasters, exceeding the minimum increase? (3) Does the adverse effect on the consequences of the accident sequence exceed the minimum increase? (4) Does the adverse effect on the fission product barrier capability exceed the minimum reduction? (5) Does it result in an adverse impact on defense-in-depth capability or security margin exceeding the minimum reduction? The first question identifies whether the frequency of established initiating events affected by the proposed change has significantly increased, and also determines whether it has led to any new accident triggers. When determining whether the frequency of existing initiating events exceeds the minimum limit due to the proposed change, reasonable recommendations should be given based on professional practice, engineering judgment, and PSA (Power, Service, Allocation) techniques. The second question involves numerous factors related to the reliability and availability of SSCs (Self-Controlled Controllers) or personnel; quantification of performance changes can be achieved through appropriate calculation methods. The second question assesses performance changes; if the performance change is very small, or the uncertainty leading to the performance change is too great to reasonably conclude the actual magnitude of the change, then the impact of the proposed change on performance change is considered negligible. The third question determines whether the resulting accident sequence consequences have significantly increased, using a risk increment exceeding 10% of the original value as the criterion. The fourth question assesses whether the proposed change has a significant impact on the safety of fission product barriers (including fuel cladding, reactor primary coolant pressure boundaries, and containment). The fifth question can be based on the standards in NNSA-0147, and a detailed analysis of the impact of the proposed changes on the seven principles of defense-in-depth in power plants and the requirements for adequate safety margins can be conducted by combining deterministic and probabilistic analysis.

[0045] After completing the final security impact screening assessment of the proposed change, if the answer to all the above questions is "no", the proposed change will be screened as having the smallest security impact event sequence range.

[0046] In some executable embodiments, S30 includes: Obtain the filtered records of the items to be changed in step S20.

[0047] Using a consensus-based decision-making process, qualitative and / or quantitative assessments of the screening items are conducted based on screening records to obtain assessment results.

[0048] Adjust the corresponding parameters in the corresponding PSA model based on the feedback from the evaluation results.

[0049] In some embodiments, the affected model parameters in the PSA model are obtained based on the filtering criteria.

[0050] The model parameters are adjusted based on the evaluation results to obtain specific parameters.

[0051] Based on the funnel-shaped hierarchical screening mechanism and the evaluation process and corresponding evaluation results of the consensus decision-making procedure, the model parameters affecting the screening items are adjusted and then determined as specific parameters of the model.

[0052] Through detailed definition and relevant analysis of specific events, it is crucial to identify the affected "SSCs," "personnel actions," and "accident sequences" that need to be included in the PSA model modification. Furthermore, the data inputs to the model must use "verified baseline data" (such as equipment failure probability, human error probability, etc.), avoiding the use of data that has not been peer-reviewed. If the event involves new equipment or processes, "industry experience data" or "manufacturer-provided verified data" must be used as input. Simultaneously, it is necessary not only to assess the direct impact of specific events but also to identify other indirect or related impacts, including potential effects on multiple specific functions or other aspects of the power plant, ensuring that no potential risks are overlooked in the assessment.

[0053] Once the specific parameters are determined, they need to be calculated in the PSA model to quantitatively assess the risk level of the corresponding items to be changed.

[0054] In some executable embodiments, the risk data includes incremental risk data and cumulative risk data.

[0055] S40 includes: The risk level of the screened items is calculated using the PSA model based on specific parameters, resulting in incremental risk data and cumulative risk data.

[0056] In one embodiment, the risk increment data includes: core damage frequency increment and large early radioactive release frequency increment.

[0057] The cumulative risk data includes: the cumulative core damage frequency and the frequency of large-scale early radioactive releases after the power plant baseline risk is superimposed with the risk increment data of the screened items.

[0058] Understandably, in this embodiment, only the core damage frequency increment, the large number of early radioactive release frequency increments, the cumulative core damage frequency, and the cumulative large number of early radioactive release frequencies need to be calculated, which to some extent reduces the amount of calculation required for risk assessment of the items to be changed and improves the efficiency of risk assessment for low-risk items to be changed.

[0059] In one embodiment, S50 includes: Determine whether the incremental risk data is less than the preset risk threshold.

[0060] If so, calculate the cumulative risk data for the selected items.

[0061] If the cumulative risk data is less than the preset cumulative risk threshold, the item to be changed corresponding to the risk data will be used as the screening and evaluation result.

[0062] If the incremental risk data is greater than or equal to the preset incremental risk threshold, the item to be changed is directly determined to be ineligible for screening; similarly, if the cumulative risk data is greater than or equal to the preset cumulative risk threshold, it is also excluded from the screening results. This step-by-step judgment method systematically assesses the risk impact of the screened items, ensuring that only those items with both incremental and cumulative risks within acceptable ranges are ultimately selected. This improves the accuracy and reliability of screening low-risk items to be changed while ensuring the operational safety of the nuclear power plant.

[0063] Based on the above overall logic, specific risk indicators are used for quantitative judgment: First, it is determined whether the core damage frequency increment is less than the preset core damage frequency increment threshold, and whether the large number of early radioactive release frequency increment is less than the preset large number of early radioactive release frequency increment threshold; if both are satisfied, the cumulative core damage frequency and the cumulative large number of early radioactive release frequency after the change of the screening item are calculated as the power plant baseline risk; when the cumulative core damage frequency is less than the preset cumulative core damage frequency threshold, and the cumulative large number of early radioactive release frequency is less than the preset cumulative large number of early radioactive release frequency threshold, the corresponding item to be changed is used as the screening result.

[0064] By using core damage frequency increments, large early radioactive release frequency increments, cumulative core damage frequencies, and cumulative large early radioactive release frequencies, the screening and evaluation process for low-risk items can be simplified, while also avoiding some ineffective or overly conservative evaluation processes.

[0065] This invention introduces a funnel-shaped hierarchical screening mechanism, using only the increment of core damage frequency, cumulative core damage frequency, increment of a large number of early radioactive release frequencies, and cumulative a large number of early radioactive release frequencies for screening. This establishes a criterion for determining low-risk events, greatly simplifying the screening process and calculation tasks, while also avoiding some ineffective or overly conservative evaluation processes. This not only simplifies complex and diverse argumentation processes and improves the efficiency of optimizing argumentation for specific matters, but also allows risk analysts to focus their time and energy on matters of higher safety importance, thereby improving the nuclear safety level of power plants.

[0066] In some embodiments, the core damage frequency increment is less than 1.0E-07 / reactor-year, and the significant early radioactive release frequency increment is less than 1.0E-08 / reactor-year.

[0067] In some embodiments, the cumulative core damage frequency is less than 1.0E-04 / reactor-year, and the cumulative early radioactive release frequency is less than 1.0E-05 / reactor-year.

[0068] In some executable embodiments, S60 includes: Based on the screened items and risk data, determine whether risk management actions are required when the items to be changed are executed.

[0069] If not, proceed directly with the changes to be made.

[0070] By screening items and risk data, we can determine the impact of the changes on security when they are implemented, and thus determine whether risk management actions are necessary.

[0071] In some embodiments, if the item to be changed is a first screening item and the risk data of the screening item meets the aforementioned threshold requirements, it is determined to be an item to be changed without security impact and there is no need to force the implementation of risk management actions.

[0072] In some embodiments, if the matter to be changed is a second screening matter, and the risk data of this screening matter meets the aforementioned threshold requirements, then the characteristic result of this matter is considered to have a minimal impact on safety. Therefore, it is considered necessary to consider implementing risk management actions to offset or mitigate the increased risk caused by this matter. However, the consideration of risk management actions cannot be used to change the quantitative risk assessment results. If this specific matter is subsequently approved (becoming a permanent configuration of the power plant), then the temporary risk management actions will also become permanent measures.

[0073] In some embodiments, S60 further includes: Develop a performance monitoring strategy based on the screening criteria.

[0074] Develop performance monitoring strategies for screened items to ensure that engineering assessments supporting proposed changes remain valid in the future. Thoroughly monitor Service Controllers (SSCs) whose performance degradation could adversely affect the proposed changes. For specific items involving changes to the license's underlying structure, regulators should review the licensee's implementation of performance monitoring measures to ensure that conclusions supporting the proposed changes remain valid in the future.

[0075] The present invention also provides a computer device, including a memory and a processor; the memory stores a computer program.

[0076] The processor executes the steps of the screening and evaluation method for low-risk events in nuclear power plants, as described above, by calling computer programs stored in memory.

[0077] The above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for screening and evaluating low-risk items in nuclear power plants, characterized in that, Includes the following steps: S10: Determine whether the items to be changed can be modeled using the PSA model; S20: If so, the funnel-shaped hierarchical screening mechanism is used to screen the items to be changed to obtain the screened items; S30: Perform a security analysis on the selected items to obtain specific parameters; S40: Calculate the risk level of the screened item using the PSA model based on the specific parameters to obtain risk data; S50: Determine whether the risk data meets the preset risk threshold requirements to obtain the screening results; S60: Based on the screening, determine the necessity of taking risk management actions and formulate a performance monitoring strategy after implementing the screening.

2. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, S10 includes: Determine whether the items to be changed are timely actions to ensure the safe operation of the unit and timely maintenance required to ensure the unit continues to generate electricity; If not, determine whether the matter to be changed can be modeled using the PSA model.

3. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, S20 includes: The funnel-shaped hierarchical screening mechanism is used to screen the items to be changed through at least two sets of preset general security questions to obtain the screened items.

4. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, S30 includes: Obtain the filtering record of the filtering item in S20; Using a consensus decision-making process, the screening items are qualitatively and / or quantitatively evaluated based on the screening records to obtain evaluation results; The specific parameters in the corresponding PSA model are adjusted based on the feedback from the evaluation results.

5. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, The calculation of the risk data includes calculating incremental risk data and cumulative risk data; S40 includes: The risk level of the screened item is calculated using the PSA model based on the specific parameters, thereby obtaining the risk increment data and the cumulative risk data.

6. The method for screening and evaluating low-risk items in nuclear power plants according to claim 5, characterized in that, Risk increment data includes: increments in the frequency of core damage and increments in the frequency of large-scale early radioactive releases; The cumulative risk data includes: the cumulative core damage frequency and the cumulative frequency of large-scale early radioactive releases after the power plant baseline risk is superimposed with the risk increment data of the screened items.

7. The method for screening and evaluating low-risk items in nuclear power plants according to claim 5, characterized in that, The S50 includes: Determine whether the risk increment data is less than a preset risk increment threshold; If so, calculate the cumulative risk data for the selected items; If the cumulative risk data is less than the preset cumulative risk threshold, then the item to be changed corresponding to the risk data will be used as the filtering result.

8. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, The S60 includes: Based on the category of the screened items and the risk data, determine whether risk management actions are required when the item to be changed is executed; if not, execute the item to be changed directly.

9. The method for screening and evaluating low-risk items in nuclear power plants according to claim 1, characterized in that, The S60 further includes: The performance monitoring strategy is formulated after the screening criteria are implemented.

10. A computer device, characterized in that, It includes a memory and a processor; the memory stores a computer program; The processor executes the steps of the screening and evaluation method for low-risk events in nuclear power plants as described in any one of claims 1 to 9 by calling the computer program stored in the memory.

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