Safety analysis method and system for heat pipe micro-stack

Abstract

The invention provides a safety analysis method and system for a heat pipe micro-stack. The method comprises the following steps: carrying out key phenomenon identification and grading analysis on design characteristics of the heat pipe micro-stack to obtain a heat pipe micro-stack phenomenon grading table; performing failure mode and influence analysis based on the design characteristics of the heat pipe micro-stack and the heat pipe reaction phenomenon grading table to obtain a heat pipe micro-stack accident list; determining safety criteria of the heat pipe micro-reactor according to important components of the heat pipe micro-reactor, safety regulations of the nuclear power plant and the accident list of the heat pipe micro-reactor; determining a potential protection signal list of the heat pipe micro-stack according to the heat pipe micro-stack safety criterion and the heat pipe micro-stack accident list; according to a legal protection signal requirement and a design constraint condition, implementing optimization is carried out on the potential protection signal list, and a preliminary protection signal list is determined; and performing key accident verification on the protection signals in the primary protection signal list to obtain a final protection signal list.

Description

Technical Field

[0001] The present invention mainly relates to a nuclear micro-reactor safety design, and in particular to a safety analysis method and system for a heat pipe micro-reactor. Background Art

[0002] In nuclear power plants, protection signals are physical parameters used for operating status monitoring and accident condition monitoring, which activate the protection system when the change exceeds the safety setting value. In the research and development stage of new reactor types, protection signals are the prerequisite for scheme design and safety analysis. Therefore, the comprehensiveness and effectiveness of the protection signal list are crucial to the safe operation of nuclear power plants.

[0003] Heat pipe micro-reactor refers to a solid-state reactor in which the primary loop system of the micro-reactor does not adopt a coolant loop arrangement, but uses heat pipes to transfer the heat generated by the core to the secondary loop system or the thermoelectric conversion system. Compared with traditional pressurized water reactors, high-temperature gas-cooled reactors and other reactor models, heat pipe micro-reactors have the following differences: 1) The equipment is very different, no main pump is required, and the main equipment includes fuel rods, matrix, high-temperature heat pipes, shielding, drive mechanism, dedicated exhaust system and thermodynamic conversion module, etc.; 2) The heat transfer path is very different. The fuel rod conducts heat to the matrix, and then conducts heat to the evaporation end of the high-temperature heat pipe. The heat is transferred to the condensation section of the heat pipe through the evaporation and condensation process of the working fluid inside the heat pipe, and then the heat is transferred to the hot end of the thermoelectric conversion device / secondary loop system through natural circulation. After the thermoelectric conversion device / secondary loop system converts thermal energy into electrical energy, the remaining waste heat is discharged to the final heat sink (atmosphere or environment) through the heat exchanger.

[0004] Due to the gaps in the above equipment and heat transfer paths, new key phenomena and characteristics have been generated in heat pipe micro-reactors. For heat pipe micro-reactors, the existing safety analysis methods and regulatory requirements are no longer applicable. It is necessary to conduct research on safety analysis methods and form a safety analysis system suitable for heat pipe micro-reactors to support the research and development of heat pipe micro-reactors. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for safety analysis of a heat pipe micro-reactor.

[0006] To solve the above technical problems, the present invention provides a safety analysis method for a heat pipe micro-reactor, comprising the following steps: performing key phenomenon identification and hierarchical analysis on the design features of the heat pipe micro-reactor to obtain a heat pipe micro-reactor phenomenon grading table, wherein the heat pipe micro-reactor phenomenon grading table includes phenomenon items, grading items and requirement items; performing failure mode and effect analysis based on the design features of the heat pipe micro-reactor and the heat pipe reaction phenomenon grading table to obtain a heat pipe micro-reactor accident list, wherein the heat pipe micro-reactor accident list includes at least one accident category, and each accident category includes one or more accidents; determining heat pipe micro-reactor safety criteria according to important components of the heat pipe micro-reactor, nuclear power plant safety regulations and the heat pipe micro-reactor accident list, wherein each heat pipe micro-reactor safety criteria involves at least one protection signal; determining a potential protection signal list for the heat pipe micro-reactor according to the heat pipe micro-reactor safety criteria and the heat pipe micro-reactor accident list, wherein the potential protection signal list includes at least one potential protection signal; optimizing the feasibility of the potential protection signal list according to statutory protection signal requirements and design constraints to determine a preliminary protection signal list; and performing key accident verification on the protection signals in the preliminary protection signal list to obtain a final protection signal list.

[0007] Optionally, the step of performing a failure mode and effect analysis based on the design features of the heat pipe micro-repile and the heat pipe reaction phenomenon classification table to obtain a heat pipe micro-repile accident list includes: analyzing the potential failure modes of equipment and components in the design features of the heat pipe micro-repile one by one to obtain a deterministic preliminary accident list; dividing the design features of the heat pipe micro-repile into multiple systems, analyzing the failure mode of each system to obtain an initiating event list, the initiating event list including system entries, failure mode entries and initiating event entries, the multiple systems including a core, a main heat transfer system, a reactivity control drum drive mechanism, a safety shutdown rod drive mechanism, a thermoelectric conversion system, a passive residual heat removal system, an electrical system, and a control and protection system; and comparing the preliminary accident list with the initiating event list to obtain the heat pipe micro-repile accident list.

[0008] Optionally, the step of determining the safety criteria of the heat pipe micro-reactor based on the important components of the heat pipe micro-reactor, the safety regulations of the nuclear power plant and the accident list of the heat pipe micro-reactor includes: determining the important safety-related components of the heat pipe micro-reactor; performing failure mode and effect analysis on the important safety-related components to obtain a first set of safety criteria; extracting basic safety contents related to reactivity control, residual heat removal and radioactive containment in the safety regulations of the nuclear power plant; decomposing the basic safety contents into multiple safety items; determining a second set of safety criteria based on the multiple safety items and the design features of the heat pipe micro-reactor; establishing an accident analysis model; for specific accident categories in the accident list of the heat pipe micro-reactor, using the accident analysis model to analyze the thermal-hydraulic response and potential mitigation paths after the accident; forming a third set of safety criteria based on the analysis results; and obtaining the safety criteria of the heat pipe micro-reactor by combining the first to third sets of safety criteria.

[0009] Optionally, the step of determining the second set of safety criteria based on the multiple safety entries and the design features of the heat pipe micro-stack includes: establishing a design feature network of the heat pipe micro-stack; screening relevant design features in the design feature network that are related to specific safety entries among the multiple safety entries; and determining the safety criteria of the relevant design features based on the specific safety entry.

[0010] Optionally, the design feature network includes multiple layers of nodes, wherein the first layer of nodes includes micro-repile system nodes and thermoelectric conversion system nodes, the second layer of nodes includes core nodes, heat pipe nodes, main heat exchanger nodes, exhaust heat exchanger nodes and stack nodes connected to the micro-repile system nodes, and regenerator nodes, turbine nodes, compressor nodes and motor nodes connected to the thermoelectric conversion system nodes, and the third layer of nodes includes fuel rod nodes, matrix nodes, reflector nodes, drum nodes and safety rod nodes connected to the core nodes, and each node is a design feature.

[0011] Optionally, the step of determining a potential protection signal list of a heat pipe micro-repile according to the heat pipe micro-repile safety criteria and the heat pipe micro-repile accident list includes: determining a first potential protection signal list according to the safety criteria, the first potential protection signal list including at least one potential protection signal; determining a second potential protection signal list according to the heat pipe micro-repile accident list, the second potential protection signal list including at least one potential protection signal; and merging the first potential protection signal list and the second potential protection signal list into the potential protection signal list.

[0012] Optionally, the step of determining the first potential protection signal list according to the safety criterion includes: extracting keywords in each safety criterion to obtain corresponding potential protection signals; and merging the potential protection signals corresponding to each safety criterion into the first potential protection signal list.

[0013] Optionally, the step of determining a second potential protection signal list based on the heat pipe micro-reactor accident list includes: establishing an accident analysis model; for a specific accident category, using the accident analysis model to analyze the thermal-hydraulic response and potential mitigation paths after the accident; and forming potential protection signals based on the analysis results to form the second potential protection signal list.

[0014] Optionally, the step of optimizing the feasibility of the potential protection signal list according to statutory protection signal requirements and design constraints includes: for any potential protection signal in the potential protection signal list, determining whether there is a matching preliminary protection signal for any potential protection signal; if so, placing the preliminary protection signal in the preliminary protection signal list; if not, determining whether there is an alternative preliminary protection signal for any potential protection signal; if so, placing the preliminary protection signal in the preliminary protection signal list, wherein the preliminary protection signal is a protection signal that can be implemented according to the design constraints.

[0015] Optionally, the step of performing critical accident verification on the preliminary protection signal in the preliminary protection signal list includes: establishing an accident analysis model; adding the preliminary protection signal to the accident analysis model and assigning an initial value; and using the accident analysis model to analyze critical accidents, and iteratively optimizing the preliminary protection signal based on the analysis results to obtain a protection signal setting value that can alleviate the critical accident as the final protection signal.

[0016] Optionally, the potential protection signal is a shutdown protection signal or a dedicated driving signal.

[0017] Optionally, the accident categories include increased heat output of the heat pipe micro-reactor system, reduced heat removal capacity of the thermoelectric conversion system, abnormal reactivity and power distribution, decreased matrix / heat pipe heat exchange capacity, and expected transients that fail to shut down the reactor urgently.

[0018] Optionally, the above method also includes: determining a first candidate dedicated capacity of the dedicated system according to the regulations of nuclear power plants and nuclear power units; determining a second candidate dedicated capacity of the dedicated system according to the reference dedicated capacity; selecting one of the first candidate dedicated capacity and the second candidate dedicated capacity as the preliminary dedicated capacity; and performing critical accident verification on the preliminary dedicated capacity to determine the final dedicated capacity that meets the safety criteria of the dedicated system.

[0019] The present invention also proposes a safety analysis system for determining a heat pipe micro-pile, comprising: a memory for storing instructions executable by a processor; and a processor for executing the instructions to implement the method as described above.

[0020] The present invention also provides a computer storage medium storing computer program codes, which implement the above method when executed by a processor.

[0021] Compared with the prior art, the system and method of the present invention cover the processes of accident phenomenon identification and classification, list determination, safety criteria research, protection signal and dedicated safety system capacity configuration research, and key accident demonstration, forming a complete deterministic safety analysis system suitable for heat pipe micro-reactors, which effectively supports the research and development and design of heat pipe micro-reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a cross-sectional view of a micro-stack system in a heat pipe micro-stack according to an embodiment of the present application.

[0024] Figure 2 It is a cross-sectional view of a thermoelectric conversion system in a heat pipe micro-stack according to an embodiment of the present application.

[0025] Figure 3 It is a flow chart of a security analysis method according to an embodiment of the present application.

[0026] Figure 4 It is a flow chart of a method for obtaining an accident list according to an embodiment of the present application.

[0027] Figure 5 It is a flow chart of a method for obtaining safety criteria of a heat pipe micro-stack according to an embodiment of the present application.

[0028] Figure 6 is a flow chart of a method for determining a second security criterion set according to an embodiment of the present application.

[0029] Figure 7 It is a schematic diagram of a design feature network according to an embodiment of the present application.

[0030] Figure 8 It is a flow chart of a method for determining a second potential protection signal list based on a heat pipe micro-reactor accident list according to an embodiment of the present application.

[0031] Fig. 9 It is a flow chart of a method for performing critical accident verification on preliminary protection signals in a preliminary protection signal list to determine protection signal setting values ​​that meet safety criteria according to an embodiment of the present application.

[0032] Fig.10 It is a flow chart of a method for determining dedicated capacity according to an embodiment of the present application.

[0033] Fig.11 is a block diagram of a security analysis system according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0035] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0037] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0038] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0039] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0040] Figure 1 It is a cross-sectional view of a micro-stack system in a heat pipe micro-stack according to an embodiment of the present application. Figure 2 FIG. 1 is a cross-sectional view of a thermoelectric conversion system in a heat pipe micro-stack according to an embodiment of the present application. Figure 1 As shown, the micro-reactor system 10 of the present application includes a core 11, a heat pipe 12, a main heat exchanger 13, a residual heat exchanger (not shown) and a stack (not shown). The core 11 further includes a fuel rod 111, a substrate 112, a reflective layer 113, a drum 114 and a safety rod 115. The substrate 112 is cylindrical, and its cross-section can be rectangular, regular hexagonal or circular. A reflective layer 113 is arranged outside the substrate 112. The fuel rods 111 are distributed in the substrate 112 and are separated from each other. The drum 114 is inserted into the reflective layer 113 and can be rotated under the drive of the drum drive mechanism 114a to achieve the adjustment of the micro-reactor power. The control rod 115 can be movably inserted into the core 11, and can be inserted to different depths of the core 11 under the drive of the safety rod drive mechanism 115a to control the operation and stop of the micro-reactor. The heat pipe 12 is a core component responsible for heat transfer, connecting the core 11 and the main heat exchanger 13. The heat pipe 12 is located in the matrix 112 and is arranged between the fuel rods 111. Figure 2As shown, the thermoelectric conversion system 20 includes a regenerator 21, a gas turbine 22, a compressor 23, a motor 24, an air inlet 25 and an air outlet 26. The micro-reactor system 10 is mainly responsible for generating heat by micro-reactor fission and safely transferring the heat from the core 11 to the main heat exchanger 13. The thermoelectric conversion system 20 is responsible for converting the heat provided by the micro-reactor system 10 into electricity. The micro-reactor system 10 is connected to the thermoelectric conversion system 20 through an external pipeline.

[0041] In one embodiment, the size of the micro-stack system 10 and the thermoelectric conversion system 20 of the present application can be small enough to be placed on a container truck, forming a movable heat pipe micro-stack system.

[0042] The embodiment description of the present application provides a safety analysis method for a heat pipe micro-reactor, which covers the processes of accident phenomenon identification and classification, list determination, safety criterion research, protection signal and dedicated safety system capacity configuration research, and key accident demonstration, forming a systematic and complete deterministic safety analysis system suitable for heat pipe micro-reactors, effectively supporting the research and development and design of heat pipe micro-reactors.

[0043] Figure 3 is a flow chart of a security analysis method according to an embodiment of the present application. Figure 3 The safety analysis method of the heat pipe micro-stack of this embodiment is described.

[0044] In step 301, key phenomena identification and classification analysis are performed on the design features of the heat pipe micro-stack to obtain a heat pipe micro-stack phenomenon classification table. Here, the heat pipe micro-stack phenomenon classification table includes phenomenon items, classification items, and requirement items.

[0045] In step 302, a failure mode and effect analysis is performed based on the design features of the heat pipe micro-repile and the heat pipe reaction phenomenon classification table to obtain a heat pipe micro-repile accident list. The heat pipe micro-repile accident list includes at least one accident category, and each accident category includes one or more accidents.

[0046] In step 303, the heat pipe micro-reactor safety criteria are determined according to the heat pipe micro-reactor important components, nuclear power plant safety regulations and the heat pipe micro-reactor accident list, and each heat pipe micro-reactor safety criteria involves at least one protection signal.

[0047] In step 304, a potential protection signal list of the heat pipe micro-stack is determined according to the heat pipe micro-stack safety criterion and the heat pipe micro-stack accident list. Here, the potential protection signal list includes at least one potential protection signal.

[0048] In step 305, the feasibility of the potential protection signal list is optimized according to the legal protection signal requirements and design constraints to determine a preliminary protection signal list.

[0049] In step 306, critical accident verification is performed on the protection signals in the preliminary protection signal list to obtain a final protection signal list.

[0050] In the present application, the above method can be implemented in a computer-aided design manner, and one or more steps in the above method can be executed by a program. In one or more steps, the program can obtain a form, model or other data required for processing from a user or other device. In one or more steps, the program can process to obtain preliminary results and provide them to the user for reference, modification or confirmation. Based on the user's feedback, the program can modify the processing results and optimize the processing flow.

[0051] In step 301, a PIRT (Phenomena Identification And Ranking Table) analysis can be performed on the heat pipe micro-reactor during the research and development stage. PIRT analysis is used to identify important safety phenomena related to safety, and to evaluate their importance and awareness by ranking these phenomena. In this step, the objects of concern and their criteria related to the safety of the heat pipe micro-reactor are first determined. Then, the phenomena related to the safety of the heat pipe micro-reactor under the solid-state micro-reactor accident are analyzed and identified. These phenomena are phenomena that affect the objects of concern and their criteria of the heat pipe micro-reactor. Thirdly, the identified phenomena are graded to determine the importance of each phenomenon under each accident, and a heat pipe micro-reactor phenomenon grading table is formed. Finally, it is determined whether the list of key phenomena is complete and whether the phenomenon grading is reasonable to complete the PIRT analysis. Table 1 below shows an exemplary PIRT table. The program can receive one or more contents in the PIRT table entered by the user.

[0052]

[0053]

[0054] Table 1 PIRT analysis table

[0055] Figure 4 FIG. 1 is a flow chart of a method for obtaining an accident list according to an embodiment of the present application. Figure 4 The present application describes a process for performing a failure mode and effect analysis based on the design features of the heat pipe micro-repile and a heat pipe reaction phenomenon classification table to obtain a heat pipe micro-repile accident list.

[0056] In step 401, potential failure modes of equipment and components in the design features of the heat pipe micro-reactor are analyzed one by one to obtain a preliminary deterministic accident list.

[0057] In this step, the heat pipe micro-pile is divided into multiple systems and components according to the design features of the heat pipe micro-pile. Optionally, the heat pipe micro-pile is divided into a micro-pile system and a thermoelectric conversion system. The exemplary classification method is as follows: Figure 1-2 As shown. In addition, the existing accident list, the operating experience of similar nuclear power plants, the special requirements of the national nuclear safety department and the severity report of potential consequences are used as the preliminary accident list. For each of the initiating events, combined with the system and component structure of the heat pipe micro reactor, a comparison is made one by one to screen out accidents applicable to the heat pipe micro reactor. For example, referring to the accident list of pressurized water propulsion, the accident list of pressurized water reactor divides accidents into the following categories:

[0058] (1) Increased heat removal from micro-reactors;

[0059] (2) Micro-reactor heat removal is reduced;

[0060] (3) The flow rate of the micro-reactor coolant system is reduced;

[0061] (4) Abnormal reactivity and power distribution;

[0062] (5) Increased amount of coolant in micro reactors;

[0063] (6) Other events that cause emergency shutdown or rapid shutdown of the micro-reactor.

[0064] Since the heat pipe micro-reactor does not include coolant, the coolant-related accidents are no longer applicable. The coolant-related accidents are deleted, that is, the accident category of the heat pipe micro-reactor does not include (3) the flow rate of the micro-reactor coolant system is reduced and (5) the amount of micro-reactor coolant is increased. The remaining initiating events are verified to be applicable through subsequent steps. In one example, the program can obtain these design features based on the heat pipe micro-reactor model obtained from other parts.

[0065] Afterwards, based on the deterministic safety analysis method, the potential failure modes of the micro-reactor system, thermoelectric conversion system and each component were analyzed one by one, and the adverse effects of their failure on key safety functions were evaluated to obtain the accident category and specific accident.

[0066] For the remaining accidents, the deterministic safety analysis method is used to evaluate the possibility of accidents caused by failures in the micro-reactor system, the thermal-electric conversion system, and any of its components. If an accident does not meet the existing success criteria or consequence grouping, a new accident will occur.

[0067] The following is an example of a preliminary accident list based on a deterministic safety analysis approach:

[0068] Taking the accident "the air supply system air supply temperature drops" as an example, the drop in air supply temperature causes the heat pipe to increase, causing the substrate and fuel temperatures to drop, which in turn causes the core power to increase. The drop in air supply temperature may be caused by a failure in the thermoelectric conversion system or a change in ambient temperature. When the power is running, the drop in air supply temperature causes a greater load requirement on the micro-reactor heat pipe.

[0069]

[0070] Table 2 Preliminary accident list

[0071] Table 2 above is an example of a preliminary accident list. It is understood that Table 2 only shows some categories and some accidents in the heat pipe micro reactor accident list. The heat pipe micro reactor accident list of this application may include more categories and more accidents. The event categories of the preliminary accident list include:

[0072] (1) The heat output of the heat pipe micro-reactor system increases;

[0073] (2) The heat removal capacity of the thermoelectric conversion system is reduced;

[0074] (3) Abnormal reactivity and power distribution;

[0075] (4) The heat transfer capacity of the substrate / heat pipe decreases;

[0076] (5) Anticipated transients that fail to emergency shutdown.

[0077] Among them, it is important to point out that (4) the decrease in heat transfer capacity of the substrate / heat pipe is a new category of initiating events, because the substrate and heat pipe are unique components of the heat pipe micro-reactor. The initiating event list of other types of micro-reactors will not be considered. In other words, (4) the decrease in heat transfer capacity of the substrate / heat pipe is a new category of initiating events. (4) The decrease in heat transfer capacity of the substrate / heat pipe includes the initiating event-heat pipe failure accident, etc.

[0078] The above accident list is obtained based on the deterministic safety analysis method. The initiating events included may not be complete. It is necessary to use probabilistic methods and analysis requirements of radioactive source items to further sort out the preliminary accident list and obtain the final accident list, thereby supporting the determination of safety criteria and subsequent accident analysis.

[0079] In step 402, the design features of the heat pipe micro-stack are divided into multiple systems, and the failure mode of each system is analyzed to obtain an initiating event list. The initiating event list includes system entries, failure mode entries, and initiating event entries.

[0080] In this step, the design features of the heat pipe micro-reactor are divided into the following systems: core, main heat transfer system, reactivity control drum drive mechanism, safety shutdown rod drive mechanism, thermoelectric conversion system, passive residual heat removal system, electrical system, control and protection system.

[0081] Failure Mode and Effects Analysis (FMEA) is one of the important methods for system reliability and safety analysis. It analyzes system failures (results) by causes, that is, using system engineering methods, starting from each potential failure mode of the subsystem, analyzing the possible problems from bottom to top, and predicting the failure of the entire system.

[0082] The FMEA method is used to conduct a specific analysis of the initiating events that may result from the failure of a subsystem of the heat pipe micro-reactor, and to find the potential failure modes that may lead to radioactive release directly or in combination with other failures. The potential failure modes include but are not limited to operational failure, malfunction, fracture and leakage.

[0083] Afterwards, the initiating events that may be generated by each potential failure mode can be analyzed based on the probabilistic safety analysis method. First, the initiating events that may be generated by each potential failure mode and the probability of occurrence of each initiating event are calculated based on the probabilistic safety analysis method. The initiating events with a probability of occurrence greater than or equal to the preset value are taken as the initiating events corresponding to the potential failure mode. In some embodiments, the initiating events with a probability of occurrence less than the preset value but the accident consequences of the initiating events are very serious are also taken as the initiating events corresponding to the potential failure mode. Table 3 below is the potential failure modes and initiating events of the system of one embodiment. As shown in Table 3, the potential failure modes of the core include body structure failure, and the initiating events that may be generated by the failure of the body structure are matrix rupture. The initiating events that may be generated by the core operation failure are the performance degradation or failure of one or more heat pipes. The initiating event that may be generated by the rupture of the heat pipe in the matrix area of ​​the core potential failure mode-the rupture of the heat pipe is heat pipe rupture. The potential failure modes and corresponding initiating events of other subsystems refer to Table 3 and will not be repeated here.

[0084]

[0085]

[0086] Table 3 Potential failure modes and initiating events of the system

[0087] Afterwards, the initiating events are grouped to obtain an initiating event list. The principles for grouping initiating events are as follows:

[0088] 1. Initiating events with the same response system and success criteria (including automatic response of the system and operator action) to avoid unexpected radioactive release can be grouped together;

[0089] 2. In some cases, the relative importance is determined according to the frequency of the initiating events, and the initiating events that are not dominant can be merged into the dominant initiating events without the need to build a separate event tree;

[0090] 3. Determine whether the initiating event can be further divided into multiple sub-events. If so, determine whether the deviation between the radioactive release consequences of multiple sub-events is greater than the preset value. If so, divide the multiple sub-events of the initiating event into different groups. The above can be understood as that in the grouping process, it is found that some categories of initiating events need to be further subdivided because the micro-reactor response is obviously different or there is a possibility of more serious radioactive release. For example: a heat pipe rupture event, it needs to be subdivided according to the degree of rupture, rupture location, etc.;

[0091] 4. For initiating events that may directly lead to unexpected radioactive releases, since their frequency of occurrence is very low and there are no mitigation measures, there is no need to establish a special event tree for analysis, but they must be included in the frequency of unexpected radioactive releases, such as damage to storage containers.

[0092] According to the above principles, internal initiating events under power operation conditions can be divided into eight categories: accidental shutdown, transient loss of thermoelectric conversion system, general transient, rupture of heat pipes in the core area, failure of the core and reactor body, failure of the heat exchanger, and failure of radioactive shielding and containment.

[0093] As shown in Table 4 below, the event categories of the initiating event list include matrix rupture, general transient, core area heat pipe rupture, transient of loss of thermoelectric conversion system, accidental shutdown and heat exchanger failure, radioactive shielding and containment failure. Among them, heat exchanger failure and radioactive shielding and containment failure are not shown.

[0094]

[0095] Table 4 List of initiating events

[0096] In step 403, the preliminary accident list and the initiating event list are compared to obtain the heat pipe micro-reactor accident list.

[0097] Compare the preliminary accident list based on determinism with the initiating event list based on probability theory. Table 5 below is a comparison of the preliminary accident list and the initiating event list.

[0098]

[0099] Table 5 Comparison of the preliminary accident list and the initiating event list

[0100] Figure 5 FIG. 1 is a flow chart of a method for obtaining safety criteria for a heat pipe micro-stack according to an embodiment of the present application. Figure 5 The specific process of determining the safety criteria of the heat pipe micro-reactor according to the important components of the heat pipe micro-reactor, nuclear power plant safety regulations and the heat pipe micro-reactor accident list in this application is described.

[0101] In step 501, important safety-related components of the heat pipe micro-stack are determined.

[0102] In this step, the safety regulations of nuclear power plants can be used as a reference, combined with the overall safety features of heat pipe micro-reactors, to determine the important components of the heat pipe micro-reactor safety barrier. The computer program can obtain these important components based on user input.

[0103] Starting from these important components and combining them with basic safety functions (controlling reactivity; removing residual heat from the core; containing radioactive materials, shielding radiation, controlling planned emissions of radioactivity, and limiting accidental radioactive releases), the design criteria for important components of the heat pipe micro-reactor can be studied.

[0104] In step 502, a failure mode and effect analysis is performed on safety-related important components to obtain a first safety criterion set.

[0105] In this step, by analyzing the potential failure modes of important safety-related components and the potential consequences of different failures, factors that pose greater challenges to safety are identified and corresponding design criteria are obtained.

[0106] For example, the important components of heat pipe micro reactors include: fuel, matrix, heat pipe, drum, thermoelectric conversion system. For fuel, in order to meet the basic safety functions of "containing radioactive materials, shielding radiation, controlling planned radioactive emissions, and limiting radioactive releases in accidents", the integrity of the fuel rods must be ensured, that is, the integrity of both the fuel core and the cladding must be ensured, and the corresponding design criteria are as follows:

[0107] 1) Under normal operating conditions and accident conditions, the fuel pellets and cladding should not exceed the melting temperature.

[0108] 2) Under normal operating conditions and accident conditions, the fuel cladding should not exceed the stress limit considering the effects of long-term service under high temperature.

[0109] 3) Under normal operating conditions and accident conditions, the fuel cladding should not exceed the strain limit.

[0110] Regarding heat pipes, in order to meet the basic safety function of "discharging residual heat from the core", the design of heat pipes should not produce unacceptable consequences.

[0111] 1) The design power of the heat pipe should ensure sufficient safety factor (safety factor = theoretical maximum power of a single heat pipe / design power of a single heat pipe).

[0112] 2) The operating range of the heat pipe should not reach the heat transfer limit of the heat pipe (capillary limit, sonic limit, viscosity limit, carrying limit, boiling limit).

[0113] In step 503, basic safety contents related to reactivity control, residual heat removal and radioactive containment in the safety regulations of nuclear power plants are extracted.

[0114] In this step, the basic safety content regarding reactivity control, residual heat removal and radioactive containment in the safety regulations of nuclear power plants can be extracted through computer programs, and the basic safety content input into the computer program by the user through the human-computer interface can also be received.

[0115] At step 504, the basic security content is decomposed into a plurality of security items; and

[0116] In this step, the basic security content can be identified through the Natural Language Processing (NLP) model and decomposed into multiple security items. For security reasons, each security item can be reviewed and confirmed by the user before it becomes effective.

[0117] In step 505 , a second safety criterion set is determined according to a plurality of safety items and design features of the heat pipe micro-stack.

[0118] Here, the design feature of the heat pipe micro-stack is a node network composed of components of the heat pipe micro-stack, and the determination of the second safety criterion set needs to consider the design feature network represented by this node network.

[0119] Figure 6 is a flow chart of a method for determining a second security criterion set according to an embodiment of the present application. Figure 6 The following is an exemplary implementation of step 505. In step 601, a design feature network of a heat pipe micro stack is established. Figure 7 As shown, the exemplary design feature network includes multiple layers of nodes, wherein the first layer of nodes includes micro-stack system nodes and thermoelectric conversion system nodes, the second layer of nodes includes core nodes, heat pipe nodes, main heat exchanger nodes, exhaust heat exchanger nodes and stack nodes connected to the micro-stack system nodes, and regenerator nodes, turbine nodes, compressor nodes and motor nodes connected to the thermoelectric conversion system nodes, and the third layer of nodes includes fuel rod nodes, matrix nodes, reflector nodes, drum nodes and safety rod nodes connected to the core nodes, and each node is a design feature. In step 602, the design feature network is screened for relevant design features related to a specific safety item in multiple safety items. In this step, the design feature network is screened for relevant design features for a specific safety item. For example, if a certain safety item involves a certain performance requirement of the core, the nodes related to the performance requirement are screened from each subnode of the core. In step 603, the safety criteria of the relevant design features are determined according to the specific safety item. After determining the relevant design features (i.e., the nodes in the previous text), the second safety criteria set of the relevant design features is determined according to the performance requirements of the specific safety item.

[0120] For example, for the safety item "Radioactive Containment of the Core", it can be seen from the analysis that in order to limit the release of radioactivity, it is necessary to ensure that all components of the core are intact. Figure 7 From the design feature network, we can see that the integrity of the fuel rods and the matrix must be ensured. Therefore, two safety criteria are obtained: using the highest cladding temperature to ensure the integrity of the fuel cladding (fuel cladding criterion); using the highest fuel temperature to ensure the integrity of the fuel pellets (fuel pellet criterion).

[0121] In step 506, an accident analysis model is established.

[0122] Specifically, a digital model is established based on the structure of the heat pipe micro-reactor to simulate the cause of the heat pipe micro-reactor accident, the accident evolution process, accident phenomena, potential consequences of the accident and potential mitigation paths.

[0123] In step 507, for a specific accident category in the heat pipe micro-reactor accident list, an accident analysis model is used to analyze the thermal-hydraulic response after the accident and potential mitigation paths.

[0124] For a specific accident category (such as one of the categories in Table 2), the accident analysis model is used to analyze the thermal-hydraulic response and potential mitigation paths after the accident. Here, the thermal-hydraulic response represents the accident evolution process, accident phenomena, potential consequences of the accident, etc.

[0125] In step 508, a third security criterion set is formed according to the analysis result.

[0126] Here, a third safety criterion set is formed according to the analysis results.

[0127] In one embodiment, reference may also be made to existing experience with other reactor types to study corresponding safety criteria to ensure that after various accidents are effectively alleviated, components or systems can enter a safe state, thereby ensuring the safety of the heat pipe micro-reactor.

[0128] In the process of forming the third set of safety criteria, in addition to considering the common acceptance criteria for other reactor types, the design features of the heat pipe micro-reactor can also be considered comprehensively. For example, the heat pipe micro-reactor adopts a solid core design. In addition to considering temperature failure, it is also necessary to consider the effects of deformation, expansion, and bending caused by temperature, thereby determining the category of safety criteria.

[0129] For example, for the two types of accidents of decreased heat transfer capacity of the matrix / heat pipe, since the heat pipe has the safety function of performing residual heat removal, when a single, a small number or a large number of heat pipes fail due to various factors such as irradiation, deformation, common cause failure during long-term operation, the temperature of the local or overall fuel and matrix of the core will increase. If the local or overall power of the core exceeds the heat transfer limit of the adjacent heat pipe, it will cause damage to the fuel and core matrix. The potential consequences of this accident require monitoring the temperature of the fuel elements, matrix, and heat pipes to avoid core melting or damage and ensure the safety of the core. The relevant criteria obtained from the study are: fuel core temperature criteria, fuel cladding temperature criteria, heat pipe heat transfer limit criteria, etc.

[0130] In step 509 , the heat pipe micro-stack safety criterion is obtained by integrating the first to third safety criterion sets.

[0131] In this step, the first to third safety criteria sets are combined to obtain the heat pipe micro-stack safety criteria. The combination can be achieved by taking the union of multiple criteria sets.

[0132] In one embodiment, the safety criteria obtained in step 509 can also be summarized and concluded according to a preset knowledge base, so as to focus on forming accident analysis acceptance criteria. The preset knowledge base may include professional knowledge such as fuels and materials, as well as safety analysis and review experience of different reactor types, literature obtained from research, test results, etc. According to the preset knowledge base, it is possible to comprehensively judge the key thermal parameters that need to be focused on for different accident types. The above safety criteria are summarized and concluded to obtain parameters that can envelop the above safety criteria, so as to focus on forming accident analysis acceptance criteria, and finally form specific values ​​of acceptance criteria that can be used to carry out safety analysis.

[0133] For example, for the fuel pellet temperature criteria, based on fuel expertise and related test results, the fuel pellet non-melting temperature safety limit under normal operating conditions is obtained; the fuel pellet non-melting temperature safety limit under expected operating events and accident conditions is obtained. For the heat transfer limit criteria for heat pipes: under normal operating conditions, expected operating events and accident conditions, the operating range power of the wall temperature of the evaporation section of a single heat pipe should not exceed the minimum value of the four major heat transfer limits of the heat pipe (including capillary limit, sonic limit, carrying limit, and viscosity limit).

[0134] An exemplary process of the aforementioned step 304 is described as follows. First, a first potential protection signal list is determined according to the safety criteria, and the first potential protection signal list includes at least one potential protection signal. Specifically, keywords in each safety criterion are extracted to obtain the corresponding potential protection signal, and the potential protection signals corresponding to each safety criterion are merged into the first potential protection signal list. Secondly, a second potential protection signal list is determined according to the heat pipe micro-reactor accident list, and the second potential protection signal list includes at least one potential protection signal. Finally, the first potential protection signal list and the second potential protection signal list are merged into a potential protection signal list.

[0135] Based on the above example, in step 304, the keywords "maximum cladding temperature" and "maximum fuel temperature" in each safety criterion, such as the fuel cladding criterion and the fuel pellet criterion, are extracted to obtain corresponding potential protection signals: fuel cladding temperature and fuel pellet temperature. The potential protection signals corresponding to each safety criterion are merged into a first potential protection signal list. In the embodiment of the present application, the potential protection signal may be a shutdown protection signal or a dedicated drive signal.

[0136] Figure 8 1 is a flow chart of a method for determining a second potential protection signal list according to a heat pipe reactor accident list according to an embodiment of the present application. Figure 8 The exemplary implementation details of step 304 are described as shown. In step 801, an accident analysis model is established. Specifically, a digital model is established based on the structure of the heat pipe micro-repile to simulate the cause of the accident, the evolution process of the accident, the accident phenomenon, the potential consequences of the accident and the potential mitigation path of the heat pipe micro-repile accident. In step 802, for a specific accident category (such as a category in Table 1), the accident analysis model is used to analyze the thermal-hydraulic response and potential mitigation path after the accident. Here, the thermal-hydraulic response characterizes the evolution process of the accident, the accident phenomenon, the potential consequences of the accident, etc. In step 803, a potential protection signal is formed according to the analysis results to form a second potential protection signal list. Here, the potential protection signal is a protection signal that ensures that the accident safety criteria do not exceed the limit value and the accident can be effectively mitigated.

[0137] For example, in the case of an increase in heat output accident in a heat pipe micro-reactor system, the accident analysis model shows that it will introduce positive reactivity, increase the core power, and the core heat cannot be effectively removed in time, the core heat transfer will deteriorate, and the fuel element-matrix-heat pipe temperature may exceed the specified limit, resulting in damage to the fuel element and matrix. In response to this accident, the reactor must be shut down as soon as possible and the residual heat removal system must be put into use to form a shutdown protection signal: high neutron flux positive change rate, fuel pellet temperature, fuel cladding temperature, etc.; and a dedicated drive signal: fuel pellet temperature signal, fuel cladding temperature, etc.

[0138] A similar analysis method is also used for other accident categories such as accidents involving reduced heat removal capacity of thermoelectric conversion systems to obtain corresponding potential protection signals, which will not be elaborated here.

[0139] In the aforementioned step 305, on the one hand, the protection signal is optimized according to the statutory protection signal requirements. These regulations are, for example, the "Safety Regulations for Research Reactor Design" (HAF201), the IAEA safety standard SSR-3, and the GJB 843.11A-2006 "Safety Regulations for Submarine Nuclear Power Plant Design Part 11: Protection System Design Criteria". The protection signal can be optimized according to the requirements of margin, margin, diversity, and redundancy in these statutory requirements.

[0140] On the other hand, the protection signal is optimized according to the design constraints. A preliminary protection signal table can be established in advance as a design constraint. The preliminary protection signal in the table is a protection signal that can be implemented according to the design constraints. For a potential protection signal in the first potential protection signal list and the second potential protection signal list, by searching the preliminary protection signal table, it is determined whether the potential protection signal has a matching preliminary protection signal in the table. If so, it indicates that the potential protection signal is implementable, and the preliminary protection signal is directly placed in the preliminary protection signal list; if not, it indicates that the potential protection signal is not implementable, and further determines whether there is a replaceable preliminary protection signal for the potential protection signal. If so, it indicates that there is an implementable preliminary protection signal to replace the potential protection signal, so that the replaceable preliminary protection signal can be placed in the preliminary protection signal list. Generally speaking, the pre-established preliminary protection signal table contains preliminary protection signals that can replace potential protection signals. Otherwise, the user can input a preliminary protection signal that meets the requirements through the human-machine interface. Since the setting of the fuel micro-pile system involves a large number of personnel, the program can establish a collaborative workflow to allow multiple users to communicate on the substitutes of the potential protection signal to determine the available preliminary protection signal.

[0141] For example, the potential protection signals formed in step 304 include: fuel pellet temperature signals and fuel cladding temperature, etc. Due to the design characteristics of the heat pipe micro-core, the core is compactly arranged, and the matrix 112 is in direct contact with the fuel rod 111 and the heat pipe 12 (refer to Figure 1 ), there is almost no air gap, and with the current measurement technology, the core block and cladding temperature of the fuel rod 111 cannot be directly monitored. Therefore, these potential protection signals are replaced with indirect signals - matrix high temperature to monitor the safety of the core 11.

[0142] Through the above-mentioned iterative optimization, a preliminary protection signal list is formed.

[0143] Fig. 9The present invention is a flowchart of a method for performing critical accident verification on a preliminary protection signal in a preliminary protection signal list to determine a protection signal setting value that meets a safety criterion according to an embodiment of the present invention. Fig. 9 Further details of step 306 are described as shown. In step 901, an accident analysis model is established. Specifically, a digital model is established according to the structure of the heat pipe micro-pile and an accident analysis is performed to verify the effect of the preliminary protection signal. In step 902, the preliminary protection signal is added to the accident analysis model and an initial value is assigned. For example, the initial value of the temperature of the preliminary protection signal matrix high temperature obtained in the previous example is set as a basis for monitoring. In step 903, the key accident is analyzed using the accident analysis model, and the preliminary protection signal is iteratively optimized according to the analysis results to obtain the protection signal setting value and logic that can alleviate the key accident as the final protection signal. Here, the logic is a trigger logic related to the setting value. For example, "the matrix temperature reaches 800°C" is a protection signal, and the triggered logic includes "shutdown protection" and "triggering the residual discharge system after a certain delay".

[0144] For example, the shutdown protection signal and dedicated driving signal (such as substrate high temperature signal) were optimized and demonstrated for one of the key accidents, the accident of complete loss of heat exchange capacity of multiple heat pipes in the heat pipe micro-reactor. After the complete loss of heat exchange capacity of multiple heat pipes, the heat of the core exported outward by the heat pipes decreased, the local fuel assembly heated up, and the local temperature of the substrate continued to rise. When the substrate high temperature setting value was reached, the reactor was shut down. The power of the micro-reactor decreased, and the dedicated system was put into use for a certain period of time after the shutdown to continuously export heat. The temperature of the fuel core, cladding, and substrate also dropped subsequently. The entire accident process met the safety criteria, and the temperature of the fuel cladding and the temperature of the fuel core did not exceed the limit, which could effectively mitigate the accident. This shows that the substrate high temperature setting value meets the requirements and can be used as the final protection signal. Otherwise, the substrate high temperature setting value can be modified, the accident analysis model can be updated, and the key accidents can be further verified to further demonstrate the safety of the heat pipe micro-reactor.

[0145] Fig.10 is a flow chart of a method for determining dedicated capacity according to an embodiment of the present application. Fig. 9 As shown, in one embodiment, the method also includes determining a dedicated capacity, and the specific process is described as follows. In step 1001, a first candidate dedicated capacity of a dedicated system is determined according to nuclear power plant and nuclear power device regulations. In step 1002, a second candidate dedicated capacity of a dedicated system is determined according to a reference dedicated capacity. In step 1003, one of the first candidate dedicated capacity and the second candidate dedicated capacity is selected as a preliminary dedicated capacity. In step 1004, a critical accident verification is performed on the preliminary dedicated capacity to determine a final dedicated capacity that meets the safety criteria of the dedicated system.

[0146] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0147] Fig.10 Schematic diagram of the system implementation environment for security analysis according to an example of the present application. Fig.10 As shown, the system 1100 is used to implement Figure 2 The method shown may include an internal communication bus 1101, a processor 1102, a read-only memory (ROM) 1103, a random access memory (RAM) 1104, a communication port 1105, and a hard disk 1106. The internal communication bus 1101 can implement data communication between the components of the system 1100. The processor 1102 can make judgments and issue prompts. In some embodiments, the processor 1102 can be composed of one or more processors. The communication port 1105 can implement data communication between the implementation environment 1100 and the outside. In some embodiments, the implementation environment 1100 can send and receive information and data from the network through the communication port 1105. The implementation environment 1100 can also include different forms of program storage units and data storage units, such as a hard disk 1106, a read-only memory (ROM) 1103 and a random access memory (RAM) 1104, which can store various data files used for computer processing and / or communication, and possible program instructions executed by the processor 1102. The processor executes these instructions to implement the main part of the method. The above-mentioned security analysis method can be implemented as a computer program, stored in the hard disk 1106, and loaded into the processor 1102 for execution.

[0148] The present invention also includes a computer-readable medium storing a computer program code, which implements the above security analysis method when executed by a processor.

[0149] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0150] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0151] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0152] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0153] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A safety analysis method for a heat pipe micro-reactor, comprising the following steps: Performing key phenomenon identification and classification analysis on the design features of the heat pipe micro-stack to obtain a heat pipe micro-stack phenomenon classification table, wherein the heat pipe micro-stack phenomenon classification table includes phenomenon items, classification items, and requirement items; Performing a failure mode and effect analysis based on the design features of the heat pipe micro-repile and the heat pipe reaction phenomenon classification table to obtain a heat pipe micro-repile accident list, wherein the heat pipe micro-repile accident list includes at least one accident category, and each accident category includes one or more accidents; Determine the safety criteria of the heat pipe micro-reactor according to the important components of the heat pipe micro-reactor, the safety regulations of the nuclear power plant and the accident list of the heat pipe micro-reactor, each safety criterion of the heat pipe micro-reactor involves at least one protection signal; Determine a potential protection signal list of the heat pipe micro-reactor according to the heat pipe micro-reactor safety criteria and the heat pipe micro-reactor accident list, wherein the potential protection signal list includes at least one potential protection signal; Optimize the feasibility of the potential protection signal list according to the statutory protection signal requirements and design constraints, and determine the preliminary protection signal list; as well as Performing critical accident verification on the protection signals in the preliminary protection signal list to obtain a final protection signal list.

2. The method according to claim 1, characterized in that The steps of performing failure mode and effect analysis based on the design features of the heat pipe micro-repile and the heat pipe reaction phenomenon classification table to obtain a heat pipe micro-repile accident list include: Analyze the potential failure modes of equipment and components in the design features of the heat pipe micro-reactor one by one, and obtain a preliminary deterministic accident list; Dividing the design features of the heat pipe micro-reactor into multiple systems, analyzing the failure mode of each system to obtain an initiating event list, the initiating event list includes system items, failure mode items and initiating event items, the multiple systems include a core, a main heat transfer system, a reactivity control drum drive mechanism, a safety shutdown rod drive mechanism, a thermoelectric conversion system, a passive residual heat removal system, an electrical system, and a control and protection system; and The preliminary accident list and the initiating event list are compared to obtain the heat pipe micro-reactor accident list.

3. The method according to claim 1, characterized in that The steps to determine the safety criteria of heat pipe micro reactors based on the important components of heat pipe micro reactors, nuclear power plant safety regulations and the heat pipe micro reactor accident list include: Identify the safety-related critical components of the heat pipe micro-reactor; Performing a failure mode and effect analysis on the safety-related important components to obtain a first safety criterion set; Extract the basic safety contents of nuclear power plant safety regulations regarding reactivity control, residual heat removal and radioactivity containment; Decomposing the basic security content into a plurality of security items; and determining a second safety criterion set according to the plurality of safety items and design features of the heat pipe micro-stack; Establish accident analysis model; For specific accident categories in the heat pipe micro-reactor accident list, the accident analysis model is used to analyze the thermal hydraulic response and potential mitigation paths after the accident; forming a third safety criterion set according to the analysis result; and The heat pipe micro-stack safety criterion is obtained by integrating the first to third safety criterion sets.

4. The method according to claim 3, characterized in that The step of determining the second safety criteria set according to the plurality of safety items and the design features of the heat pipe micro-stack comprises: Establishing a design feature network of the heat pipe micro-stack; screening the design feature network for relevant design features related to a specific security entry among the plurality of security entries; and The safety criteria of the relevant design features are determined according to the specific safety items.

5. The method according to claim 4, characterized in that The design feature network includes multiple layers of nodes, wherein the first layer of nodes includes micro-repile system nodes and thermoelectric conversion system nodes, the second layer of nodes includes core nodes, heat pipe nodes, main heat exchanger nodes, waste heat exchanger nodes and stack nodes connected to the micro-repile system nodes, and regenerator nodes, turbine nodes, compressor nodes and motor nodes connected to the thermoelectric conversion system nodes, and the third layer of nodes includes fuel rod nodes, matrix nodes, reflector nodes, drum nodes and safety rod nodes connected to the core nodes, and each node is a design feature.

6. The method according to claim 1, characterized in that The step of determining a potential protection signal list of a heat pipe micro-reactor according to the heat pipe micro-reactor safety criteria and the heat pipe micro-reactor accident list comprises: determining a first potential protection signal list according to the safety criterion, wherein the first potential protection signal list includes at least one potential protection signal; Determine a second potential protection signal list according to the heat pipe micro-reactor accident list, wherein the second potential protection signal list includes at least one potential protection signal; The first potential protection signal list and the second potential protection signal list are combined into the potential protection signal list.

7. The method according to claim 6, characterized in that The step of determining a first potential protection signal list according to the safety criterion comprises: extracting keywords in each security criterion to obtain corresponding potential protection signals; and The potential protection signals corresponding to the safety criteria are combined into the first potential protection signal list.

8. The method according to claim 6, characterized in that The step of determining a second potential protection signal list according to the heat pipe micro-reactor accident list comprises: Establish accident analysis model; For a specific accident category, use the accident analysis model to analyze the thermal-hydraulic response after the accident and potential mitigation paths; and A potential protection signal is formed according to the analysis result to form the second potential protection signal list.

9. The method according to claim 1, characterized in that The steps of optimizing the feasibility of the potential protection signal list according to the statutory protection signal requirements and design constraints include: For any potential protection signal in the potential protection signal list, determine whether any potential protection signal has a matching preliminary protection signal, if yes, put the preliminary protection signal into the preliminary protection signal list, if no, determine whether any potential protection signal has a replaceable preliminary protection signal, if yes, put the preliminary protection signal into the preliminary protection signal list, The preliminary protection signal is a protection signal that can be implemented according to the design constraint condition.

10. The method according to claim 1, characterized in that The steps of performing critical accident verification on the preliminary protection signals in the preliminary protection signal list include: Establish accident analysis model; Adding the preliminary protection signal to the accident analysis model and assigning an initial value; and The accident analysis model is used to analyze the critical accident, and the preliminary protection signal is iteratively optimized according to the analysis result to obtain the protection signal setting value that can alleviate the critical accident as the final protection signal.

11. The method according to claim 1, characterized in that The potential protection signal is a shutdown protection signal or a dedicated driving signal.

12. The method according to claim 1, characterized in that The accident categories include increased heat output from the heat pipe micro-reactor system, reduced heat removal capacity of the thermoelectric conversion system, abnormal reactivity and power distribution, decreased heat exchange capacity of the matrix / heat pipe, and expected transients that fail to shut down the reactor urgently.

13. The method according to claim 1, characterized in that Also includes: Determine the first candidate engineered capacity of the engineered system in accordance with nuclear power plant and nuclear power plant regulations; Determine a second candidate dedicated capacity of the dedicated system according to the reference dedicated capacity; Selecting one of the first candidate dedicated capacity and the second candidate dedicated capacity as a preliminary dedicated capacity; as well as The preliminary dedicated capacity is subjected to critical accident verification to determine a final dedicated capacity that meets the safety criteria of the dedicated system.

14. A safety analysis system for determining a heat pipe micro-reactor, comprising: a memory for storing instructions executable by a processor; as well as A processor, configured to execute the instructions to implement the method according to any one of claims 1 to 13.

15. A computer storage medium storing computer program code, wherein the computer program code, when executed by a processor, implements the method according to any one of claims 1 to 13.

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