Risk assessment monitoring method and system for nuclear power unit

Abstract

The invention discloses a risk assessment monitoring method and system for a nuclear power unit, and the method comprises the steps: obtaining a fault tree file corresponding to a shutdown signal, and carrying out the analysis of the fault tree file, so as to obtain a fault tree analysis result; bottom events of the fault tree model are extracted, and function positions and fault modes corresponding to the bottom events are determined; obtaining evaluation information of the failure mode of each device under the function position in real time, and calculating the current failure rate of the failure mode of the function position in real time; acquiring current configuration information of a room type event of the fault tree model by a user; and sending the fault tree analysis result, the current fault rate of the function position and the current configuration information of the room type event into a fault tree analysis system, and obtaining the calculated risk assessment value of the shutdown signal from the fault tree analysis system. According to the technical scheme of the invention, the calculated risk assessment value is more accurate, and the real-time monitoring of the risk state of the nuclear power unit is realized.

Description

Technical Field

[0001] The present application relates to the field of nuclear power technology, and in particular to a risk assessment and monitoring method and system for a nuclear power unit. Background Art

[0002] Accurately assessing the risk level of nuclear power units is the basis for improving nuclear safety management. At present, nuclear power plants mostly use fault tree analysis software (such as Isograph software) to conduct risk assessments on nuclear power units. When applying existing fault tree analysis software, users are required to first determine the probability of occurrence of each bottom event in the fault tree model based on the current situation of the nuclear power unit, and then send it to the fault tree analysis software for calculation to obtain the risk assessment value of the unit. This assessment method not only requires high professionalism and experience from the user, but also the assessment results are easily affected by human factors and are not accurate enough. In addition, it is impossible to achieve real-time monitoring of the risk status of the nuclear power unit. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a risk assessment and monitoring method and system for nuclear power units in view of the technical defects of the prior art, such as high requirements on personnel professionalism, susceptibility to human factors and inability to monitor risk status in real time.

[0004] The technical solution adopted by the present invention to solve the technical problem is: construct a risk assessment and monitoring method for a nuclear power unit, which is applied to a risk assessment and monitoring system, and the risk assessment and monitoring system is communicatively connected with a fault tree analysis system, and for each shutdown signal, the following are performed:

[0005] Step S10, obtaining a fault tree file corresponding to the shutdown signal from the fault tree analysis system, and parsing the fault tree file to obtain a fault tree parsing result, wherein the fault tree file includes a fault tree model pre-established for the shutdown signal;

[0006] Step S20, extracting the bottom events of the fault tree model from the fault tree analysis result, and determining the functional positions and fault modes corresponding to the bottom events respectively;

[0007] Step S30, for each functional position of the bottom event, obtaining in real time evaluation information of the failure mode occurring in each device under the functional position, and calculating in real time the current failure rate of the failure mode occurring in the functional position according to the evaluation information;

[0008] Step S40, obtaining the user's current configuration information for the room type event of the fault tree model;

[0009] Step S50, sending the fault tree analysis result, the current failure rate of the functional position, and the current configuration information of the room type event to the fault tree analysis system, and obtaining the calculated risk assessment value of the shutdown signal from the fault tree analysis system.

[0010] Optionally, the step S30 includes:

[0011] Step S31, for each functional position of the bottom event, obtain the equipment health assessment score of each equipment under the functional position from the equipment health assessment system, and determine whether the equipment failure rate of the corresponding equipment under the functional position that occurs in the failure mode can be obtained from the equipment health assessment system, wherein the equipment failure rate is the equipment operation failure rate or the equipment demand failure rate. If not, execute step S32; if yes, execute step S33;

[0012] Step S32, obtaining the initial failure rate of the failure mode occurring at the functional position from the fault tree analysis result, and using it as the current failure rate of the failure mode occurring at the functional position, and then executing step S40;

[0013] Step S33, according to the failure rate conversion rule pre-configured by the user, convert the device health assessment score of each device under the functional position into a corresponding device health assessment failure rate;

[0014] Step S34, taking the maximum value of the equipment health assessment failure rates of each device under the functional position as the functional position health assessment failure rate, and taking the maximum value of the equipment failure rates of each device under the functional position as the functional position failure rate;

[0015] Step S35, calculating the current failure rate of the functional location in which the failure mode occurs according to the functional location health assessment failure rate and the functional location failure rate, and then executing step S40.

[0016] Optionally, in step S35, the current failure rate of the failure mode occurring at the functional position is calculated according to the following formula:

[0017] λ=P1+P2

[0018] Wherein, λ is the current failure rate, P1 is the health assessment failure rate of the functional position, and P2 is the failure rate of the functional position.

[0019] Optionally, after step S50, the method further includes:

[0020] Step S60, displaying the risk assessment value of the shutdown signal within a preset time period in the form of a trend graph.

[0021] Optionally, after step S50, the method further includes:

[0022] Step S70, predicting the incremental risk of shutdown at a future time point according to the risk assessment value of the shutdown signal within a preset time period, and outputting the incremental risk of shutdown.

[0023] Optionally, after step S50, the method further includes:

[0024] Step S80, determining the risk level corresponding to the risk assessment value of the shutdown signal according to a preset risk level table, wherein the risk level table includes a plurality of risk levels and a risk assessment range corresponding to each risk level.

[0025] Optionally, after step S50, the method further includes:

[0026] When a first viewing instruction input by a user is received, intermediate calculation information is obtained from the fault tree analysis system and output, wherein the intermediate calculation information includes at least one of the following: bottom event list information, intermediate event list information, static cut set list information, dynamic cut set list information, and risk importance list information.

[0027] Optionally, it also includes:

[0028] When receiving the second viewing instruction input by the user, obtaining shutdown signal list information and outputting the shutdown signal list information, wherein the shutdown signal list information includes a signal code, a signal description, a signal state, an applicable unit, and a monitoring state of each shutdown signal;

[0029] When receiving the operation instruction input by the user, the corresponding shutdown and stacking signal is managed and operated.

[0030] Optionally, it also includes:

[0031] When a third viewing instruction input by the user is received, a fault tree model of the shutdown signal is acquired and the fault tree model is displayed.

[0032] The present invention also constructs a risk assessment and monitoring system for a nuclear power unit, comprising a processor and a memory storing a computer program, wherein the processor implements the steps of any of the above-mentioned risk assessment and monitoring methods for a nuclear power unit when executing the computer program.

[0033] Through the technical solution of the present application, the bottom events of the fault tree model are obtained by parsing the fault tree file of the shutdown signal, and then the functional positions and fault modes corresponding to each bottom event are determined, and then the evaluation information of the fault mode of each device under each functional position is obtained in real time, and the current failure rate of the fault mode at the functional position is calculated. In addition, the user's current configuration information of the room type event of the fault tree model is also obtained. Finally, this information is sent to the fault tree analysis system in real time to calculate the risk assessment value of the shutdown signal in real time. This risk assessment and monitoring method no longer requires users to estimate the probability of occurrence of each bottom event based on professional experience, and has lower requirements on the user's professionalism and experience, and also avoids human errors, so the calculated risk assessment value is more accurate, and it realizes real-time monitoring of the risk status of nuclear power units. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0035] Figure 1 It is a flow chart of Embodiment 1 of the risk assessment and monitoring method for a nuclear power unit of the present invention;

[0036] Figure 2 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0037] Figure 3 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0038] Figure 4 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0039] Figure 5 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0040] Figure 6 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0041] Figure 7 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0042] Figure 8 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0043] Fig. 9 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0044] Fig.10 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention;

[0045] Fig.11 This is a page diagram of a risk assessment and monitoring system for a nuclear power unit in one embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] Figure 1 1 is a flow chart of a first embodiment of a risk assessment and monitoring method for a nuclear power unit of the present invention. The risk assessment and monitoring method of this embodiment is applied to a risk assessment and monitoring system. The risk assessment and monitoring system is connected to a fault tree analysis system. The fault tree analysis system is, for example, an Isograph software system. The Isograph software is a reliability, availability, safety, maintainability and security engineering design analysis software based on a fault tree model. In this embodiment, for each shutdown signal, the following is performed:

[0048] Step S10, obtaining a fault tree file (e.g., a file in rwb format) corresponding to the shutdown signal from the fault tree analysis system, and parsing the fault tree file to obtain a fault tree parsing result, wherein the fault tree file includes a fault tree model pre-established for the shutdown signal;

[0049] Step S20, extracting the bottom event of the fault tree model from the fault tree analysis result, and determining the functional position and failure mode corresponding to the bottom event, wherein the failure mode includes, for example, shutdown, overload, etc.;

[0050] Step S30, for each functional position of the bottom event, obtaining in real time evaluation information of the failure mode occurring in each device under the functional position, and calculating in real time the current failure rate of the failure mode occurring in the functional position according to the evaluation information;

[0051] Regarding this step, it should be noted that the evaluation information of each failure mode of each device under the functional position corresponding to the bottom event can be obtained from the existing component / equipment health assessment system, and the evaluation information of the component / equipment is based on the pre-established component / equipment health assessment model and is determined according to the actual monitoring data of the corresponding measuring points of the component / equipment.

[0052] Step S40, obtaining the user's current configuration information for the room type event of the fault tree model;

[0053] Step S50, sending the fault tree analysis result, the current failure rate of the functional position, and the current configuration information of the room type event to the fault tree analysis system, and obtaining the calculated risk assessment value of the shutdown signal from the fault tree analysis system.

[0054] In this embodiment, the bottom events of the fault tree model are obtained by parsing the fault tree file of the shutdown signal, and then the functional positions and fault modes corresponding to each bottom event are determined, and then the evaluation information of the fault mode of each device under each functional position is obtained in real time, and the current failure rate of the fault mode of the functional position is calculated. In addition, the user's current configuration information of the room type event of the fault tree model is also obtained. Finally, this information is sent to the fault tree analysis system in real time to calculate the risk assessment value of the shutdown signal in real time. This risk assessment and monitoring method no longer requires users to estimate the probability of occurrence of each bottom event based on professional experience, and has lower requirements on the user's professionalism and experience, and also avoids human errors, so the calculated risk assessment value is more accurate, and the real-time monitoring of the risk status of the nuclear power unit is realized.

[0055] Further, in an optional embodiment, step S30 includes:

[0056] Step S31, for each functional position of the bottom event, obtain the equipment health assessment score of each equipment under the functional position from the equipment health assessment system, and determine whether the equipment failure rate of the corresponding equipment under the functional position that occurs in the failure mode can be obtained from the equipment health assessment system, wherein the equipment failure rate is the equipment operation failure rate or the equipment demand failure rate. If not, execute step S32; if yes, execute step S33;

[0057] Step S32, obtaining the initial failure rate of the failure mode occurring at the functional position from the fault tree analysis result, and using it as the current failure rate of the failure mode occurring at the functional position, and then executing step S40;

[0058] Step S33, according to the failure rate conversion rule pre-configured by the user, convert the device health assessment score of each device under the functional position into a corresponding device health assessment failure rate;

[0059] Step S34, taking the maximum value of the equipment health assessment failure rates of each device under the functional position as the functional position health assessment failure rate, and taking the maximum value of the equipment failure rates of each device under the functional position as the functional position failure rate;

[0060] Step S35, calculating the current failure rate of the functional location in which the failure mode occurs according to the functional location health assessment failure rate and the functional location failure rate, and then executing step S40.

[0061] In this embodiment, the evaluation information of the equipment includes the equipment health assessment score and the equipment failure rate of the equipment in the failure mode, and the equipment failure rate is the equipment operation failure rate or the equipment demand failure rate. After obtaining the equipment health assessment scores of each device under the functional position from the equipment health assessment system, it is determined whether the equipment failure rate of the corresponding device under the functional position in the failure mode can be obtained from the equipment health assessment system. If not, it means that the equipment health assessment system has not configured the failure assessment model of the corresponding device under the functional position in the failure mode, or, although the corresponding failure assessment model is configured, the corresponding measurement point value is missing in the monitoring information, and it is not necessary to recalculate the current failure rate of the failure mode at the functional position, that is, use the initial failure rate of the fault tree model; if the equipment failure rate of each device under the functional position in the failure mode can be obtained, first convert the equipment health assessment score of each device into the corresponding equipment health assessment failure rate, then select the maximum value from the equipment health assessment failure rates of multiple devices, and select the maximum value from the equipment failure rates of multiple devices, and finally calculate the current failure rate of the failure mode at the functional position based on these maximum values.

[0062] Further, in an optional embodiment, in step S35, the current failure rate of the functional position in which the failure mode occurs is calculated according to the following formula:

[0063] λ=P1+P2

[0064] Wherein, λ is the current failure rate, P1 is the health assessment failure rate of the functional position, and P2 is the failure rate of the functional position.

[0065] Furthermore, in an optional embodiment, after step S50, the method further includes:

[0066] Step S60, displaying the risk assessment value of the shutdown signal within a preset period of time in the form of a trend graph. Figure 2As shown, the risk assessment value in the past seven days is displayed in area A1. In addition, the cut set statistics information can also be displayed on this page, including: displaying the number and proportion of the first-order, second-order, third-order, and fourth-order cut sets.

[0067] Furthermore, in an optional embodiment, after step S50, the method further includes:

[0068] Step S70, predicting the incremental risk of shutdown at a future time point according to the risk assessment value of the shutdown signal within a preset time period, and outputting the incremental risk of shutdown. Figure 2 As shown, the shutdown risk increment for the next 24 hours is displayed in area A2.

[0069] Furthermore, in an optional embodiment, after step S50, the method further includes:

[0070] Step S80, according to a preset risk level table, determine the risk level corresponding to the risk assessment value of the shutdown signal, wherein the risk level table includes multiple risk levels and the risk assessment range corresponding to each risk level. For example, the risk level table includes three risk levels: high risk, medium risk, and low risk, wherein the risk assessment range corresponding to high risk is a risk assessment value between 0.006-1, the risk assessment range corresponding to medium risk is a risk assessment value between 0.004-0.006, and the risk assessment range corresponding to low risk is a risk assessment value between 0-0.004.

[0071] Furthermore, in an optional embodiment, after step S50, the method further includes:

[0072] When a first viewing instruction input by a user is received, intermediate calculation information is obtained from the fault tree analysis system and output, wherein the intermediate calculation information includes at least one of the following: bottom event list information, intermediate event list information, static cut set list information, dynamic cut set list information, and risk importance list information.

[0073] In this embodiment, the first viewing instruction includes: viewing the bottom event list, viewing the intermediate event list, viewing the static cut set list, viewing the dynamic cut set list, and viewing the risk importance list. When the user clicks "bottom event list", the user can Figure 3 The page shown shows the bottom event list information, which includes the event ID, event description, event type, logic mode, fault model, CCF model, sequence, remarks, hyperlink, whether it matches the fault mode, etc. corresponding to multiple bottom events. When the user clicks "Intermediate Event List", the bottom event list can be displayed in Figure 4The page shown in Figure 1 displays the intermediate event list information, which includes the event ID, event description, event type, remarks, and other information of multiple intermediate events. When the user clicks "Static Cut Set List", the user can Figure 5 The page shown in Figure 1 displays the static cut set list information, which includes the minimum cut set code, minimum cut set event description, and cut set order of each minimum cut set. When the user clicks "Dynamic Cut Set List", the user can Figure 6 The page shown in the figure displays the dynamic cut set list information, which includes the minimum cut set code, minimum cut set event description, and cut set order of each minimum cut set. When the user clicks on "Risk Importance List", the dynamic cut set list can be viewed in the following ways: Figure 7 The page shown shows the risk importance list information, which includes event ID, event description, static importance, dynamic importance, fault model category, functional location failure rate, number of equipment failure modes, RRW, RAW, matching functional location failure mode, etc. Moreover, shutdown importance application decision judgment rules: RAW criterion value and RRW criterion value divide the coordinate axis into 4 areas, each area represents a type of application decision. ① Critical equipment / no need to optimize: RAW ≥ RAW criterion value, and RRW < RRW criterion value; ② Critical equipment / optimizable: RAW ≥ RAW criterion value, and RRW ≥ RRW criterion value; ③ Non-critical equipment / optimizable: RAW < RAW criterion value, and RRW ≥ RRW criterion value; ④ RTM equipment: RAW < RAW criterion value, and RRW < RRW criterion value.

[0074] Furthermore, in an optional embodiment, the method further comprises:

[0075] When receiving the second viewing instruction input by the user, obtaining shutdown signal list information and outputting the shutdown signal list information, wherein the shutdown signal list information includes a signal code, a signal description, a signal state, an applicable unit, and a monitoring state of each shutdown signal;

[0076] When receiving the operation instruction input by the user, the corresponding shutdown and stacking signal is managed and operated.

[0077] In this embodiment, the second viewing instruction includes a shutdown signal viewing instruction and a shutdown signal viewing instruction. Taking the shutdown signal as an example, when the user clicks "shutdown signal management", in the following example, Figure 8The page shown displays the shutdown signal list information, which includes the signal code, signal description, applicable base, applicable unit, consequence type, set value, action logic, compliance condition, signal status (effective, ineffective, draft, calculating, null value), risk status, monitoring status (normal, warning, alarm), etc. of each shutdown signal. In addition, the user can view, modify, delete, etc. in area A3.

[0078] Furthermore, in an optional embodiment, the method further comprises:

[0079] When a third viewing instruction input by the user is received, a fault tree model of the shutdown signal is acquired and the fault tree model is displayed.

[0080] In this embodiment, when the user clicks on “Fault Tree Model”, Fig. 9 The page shown shows the fault tree model. Regarding the fault tree model, it should be noted that all the information of the fault tree model is taken from the uploaded fault tree file, and the acquisition method is to directly parse the RWB format file. Fig. 9 As shown, the structure tree on the left shows the fault tree, events, and CCF model information, among which:

[0081] In the structure tree on the left, under the fault tree branch: ① The top event and the logic gate event with paging checked are displayed in the structure tree on the left, and the corresponding attachment relationship is displayed. ② Attachment rules: The top event is the one without a superior, and the top event is the first level. The logic gate event with paging checked keeps looking up for the superior until the superior is another logic gate event with paging checked or the top event. ③ The attachment relationship can be sorted and stored separately after each model file is uploaded. ④ Click to switch paging. ⑤ After paging, the logic gate event with paging checked has a small triangle next to the logic gate to prompt that it has a superior.

[0082] In the structure tree on the left, under the event branch: all bottom events that appear on the current page are displayed. Double-click to view details.

[0083] In the structure tree on the left, under the CCF model branch: all CCF models of this fault tree are displayed. Double-click to view details. Including ID, CCF model group, description, CCF model type, β value, remarks, hyperlink, and correlation.

[0084] like Fig. 9As shown, in the model area, when the user double-clicks an event, a pop-up window appears, showing detailed information, including event ID, event description, event type, logic mode, fault model, CCF model, sequence, notes, hyperlinks, and correlations. Users can also click on the fault mode information to jump to the reliability model library-fault model page. Users click on the device information to jump to the configuration configuration microservice page to view the device information. Click on the reliability index to jump to the electronic resume library-indicator statistics. In addition, in the model area, when the user double-clicks the logic gate, a pop-up window appears, showing detailed information, including ID, description, type, identification, number of votes, modularization, paging information, notes, hyperlinks, and correlations.

[0085] In addition, if Fig. 9 As shown, users can query by manually entering ID, description, category (logic gate, event), type (type corresponding to logic gate or event) or selecting from the drop-down box. Logic gate type options: AND gate, OR gate, voting gate, NOT gate, XOR gate, inhibition gate, priority AND gate, transfer gate, empty gate. Event type options: basic event, unexpanded event, conditional event, room type event, hidden event. In addition, users can view the historical version of the fault tree model by clicking "Historical Version". Each time a user uploads a fault tree file, the system assigns a version number and upgrades the version to 0.1. The initial version is V1.0. When switching to the historical version, you can only view the fault tree model tab, and you cannot switch to the cut set list and risk assessment tab. The fault tree model can also be uploaded / downloaded by users. When an authorized user uploads a fault tree model file from the local computer, the format needs to be verified, which should be in RWB format. When downloading, the latest version of the RWB format fault tree model file is downloaded.

[0086] The user can also click in the model area and drag with the mouse to drag the whole, and control the display ratio by dragging left and right. Click again to restore the normal mode and reset to the initial state. The user can configure the color of the fault tree as a whole in the pop-up window that appears after clicking.

[0087] Furthermore, in Fig. 9 In the fault tree model shown, the user can configure the room type event calculation rules by clicking the room type event of the fault tree model, and can directly obtain the allowable signal calculation rules of the unit from the qualified list. After completing the configured room type event, such as Fig.10 As shown, it is also marked in the structure tree on the left.

[0088] Furthermore, users can configure the failure rate conversion rules. When users click on “Health Assessment Failure Rate”, they will enter the following Fig.11The page shown in the figure, on which the user can configure the failure rate conversion rule, for example, the configured failure rate conversion rule is: if the health score of the device is greater than 99 and less than level 100, the health assessment failure rate of the device is 0.001; if the health score of the device is greater than 98 and less than or equal to 99, the health assessment failure rate of the device is 0.003; if the health score of the device is greater than 97 and less than or equal to 98, the health assessment failure rate of the device is 0.005; if the health score of the device is greater than 96 and less than or equal to 97, the health assessment failure rate of the device is 0.007; if the health score of the device is greater than 95 and less than or equal to 99, the health assessment failure rate of the device is 0.008; If the health score of the device is less than or equal to 96, the health assessment failure rate of the device is 0.008; if the health score of the device is greater than 90 and less than or equal to 95, the health assessment failure rate of the device is 0.01; if the health score of the device is greater than 80 and less than or equal to 90, the health assessment failure rate of the device is 0.02; if the health score of the device is greater than 70 and less than or equal to 80, the health assessment failure rate of the device is 0.03; if the health score of the device is greater than 60 and less than or equal to 70, the health assessment failure rate of the device is 0.04; if the health score of the device is greater than 50 and less than or equal to 60, the health assessment failure rate of the device is 0.05.

[0089] The present invention also constructs a risk assessment and monitoring system for a nuclear power unit, the risk assessment and monitoring system comprising a processor and a memory storing a computer program, and the processor implements the steps of the risk assessment and monitoring method for a nuclear power unit described above when executing the computer program.

[0090] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A risk assessment and monitoring method for a nuclear power unit, applied to a risk assessment and monitoring system, wherein the risk assessment and monitoring system is communicatively connected with a fault tree analysis system, characterized in that: For each shutdown signal, perform: Step S10, obtaining a fault tree file corresponding to the shutdown signal from the fault tree analysis system, and parsing the fault tree file to obtain a fault tree parsing result, wherein the fault tree file includes a fault tree model pre-established for the shutdown signal; Step S20, extracting the bottom events of the fault tree model from the fault tree analysis result, and determining the functional positions and fault modes corresponding to the bottom events respectively; Step S30, for each functional position of the bottom event, obtaining in real time evaluation information of the failure mode occurring in each device under the functional position, and calculating in real time the current failure rate of the failure mode occurring in the functional position according to the evaluation information; Step S40, obtaining the user's current configuration information for the room type event of the fault tree model; Step S50, sending the fault tree analysis result, the current failure rate of the functional position, and the current configuration information of the room type event to the fault tree analysis system, and obtaining the calculated risk assessment value of the shutdown signal from the fault tree analysis system.

2. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: The step S30 comprises: Step S31, for each functional position of the bottom event, obtain the equipment health assessment score of each equipment under the functional position from the equipment health assessment system, and determine whether the equipment failure rate of the corresponding equipment under the functional position that occurs in the failure mode can be obtained from the equipment health assessment system, wherein the equipment failure rate is the equipment operation failure rate or the equipment demand failure rate. If not, execute step S32; if yes, execute step S33; Step S32, obtaining the initial failure rate of the failure mode occurring at the functional position from the fault tree analysis result, and using it as the current failure rate of the failure mode occurring at the functional position, and then executing step S40; Step S33, according to the failure rate conversion rule pre-configured by the user, convert the device health assessment score of each device under the functional position into a corresponding device health assessment failure rate; Step S34, taking the maximum value of the equipment health assessment failure rates of each device under the functional position as the functional position health assessment failure rate, and taking the maximum value of the equipment failure rates of each device under the functional position as the functional position failure rate; Step S35, calculating the current failure rate of the functional location in which the failure mode occurs according to the functional location health assessment failure rate and the functional location failure rate, and then executing step S40.

3. The risk assessment and monitoring method for a nuclear power unit according to claim 2, characterized in that: In step S35, the current failure rate of the failure mode occurring at the functional position is calculated according to the following formula: λ=P1+P2 Wherein, λ is the current failure rate, P1 is the health assessment failure rate of the functional position, and P2 is the failure rate of the functional position.

4. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: After step S50, the method further includes: Step S60, displaying the risk assessment value of the shutdown signal within a preset time period in the form of a trend graph.

5. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: After step S50, the method further includes: Step S70, predicting the incremental risk of shutdown at a future time point according to the risk assessment value of the shutdown signal within a preset time period, and outputting the incremental risk of shutdown.

6. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: After step S50, the method further includes: Step S80, determining the risk level corresponding to the risk assessment value of the shutdown signal according to a preset risk level table, wherein the risk level table includes a plurality of risk levels and a risk assessment range corresponding to each risk level.

7. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: After step S50, the method further includes: When a first viewing instruction input by a user is received, intermediate calculation information is obtained from the fault tree analysis system and output, wherein the intermediate calculation information includes at least one of the following: bottom event list information, intermediate event list information, static cut set list information, dynamic cut set list information, and risk importance list information.

8. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: Also includes: When receiving the second viewing instruction input by the user, obtaining shutdown signal list information and outputting the shutdown signal list information, wherein the shutdown signal list information includes a signal code, a signal description, a signal state, an applicable unit, and a monitoring state of each shutdown signal; When receiving the operation instruction input by the user, the corresponding shutdown and stacking signal is managed and operated.

9. The risk assessment and monitoring method for a nuclear power unit according to claim 1, characterized in that: Also includes: When a third viewing instruction input by the user is received, a fault tree model of the shutdown signal is acquired and the fault tree model is displayed.

10. A risk assessment and monitoring system for a nuclear power unit, comprising a processor and a memory storing a computer program, characterized in that: The processor implements the steps of the risk assessment and monitoring method for a nuclear power unit as described in any one of claims 1 to 9 when executing the computer program.

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