Reactor core non-melting evaluation method suitable for heat pipe micro-reactor

Abstract

The invention provides a systematic and comprehensive reactor core non-melting analysis and evaluation method for heat pipe micro-reactor design for the first time, and the method comprises the following steps: screening accident conditions possibly causing reactor core melting based on probability theory and engineering judgment; inputting the accident condition into a heat pipe micro-reactor analysis model, calculating the temperature of each part in the heat pipe micro-reactor under the accident condition, and evaluating whether the reactor core is damaged or not according to the temperature of each part in the heat pipe micro-reactor; inputting the temperature of each component in the heat pipe micro-reactor into a heat pipe micro-reactor mechanical model, calculating mechanical parameters of a matrix supporting a reactor core, and evaluating the structural integrity of the matrix according to the mechanical parameters; and according to whether the reactor core is damaged or not and the structural integrity of the matrix, evaluating whether the reactor core is not molten or not.

Description

Technical Field

[0001] The invention mainly relates to the field of nuclear power technology, and in particular to a core infusibility evaluation method suitable for a heat pipe micro-reactor. Background Art

[0003] The core of a heat pipe micro reactor remains intact after an accident, which can effectively prevent the release of a large amount of radioactive materials. It has the design basis and conditions to eliminate core melting. However, through domestic and foreign patent and literature searches, the existing heat pipe micro reactor patents and literature are mainly focused on the structural composition of the overall design and the overall structure of the core. No relevant technology for eliminating core melting has been found. When the research is extended to other reactor types, there are few technical achievements on the evaluation method of core non-melting. This has become a difficult problem in the design and analysis and evaluation of heat pipe micro reactors to eliminate core melting. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a core non-melting evaluation method applicable to a heat pipe micro-reactor, so as to solve the problem of the current lack of a core non-melting evaluation method for a heat pipe micro-reactor.

[0005] In order to solve the above technical problems, the present invention provides a method for evaluating the non-melting of a core of a heat pipe micro-reactor, comprising: screening accident conditions that may cause core melting based on probability theory and engineering judgment; inputting the accident conditions into a heat pipe micro-reactor analysis model, calculating the temperatures of various components in the heat pipe micro-reactor under the accident conditions, and evaluating whether the core is damaged according to the temperatures of various components in the heat pipe micro-reactor; inputting the temperatures of various components in the heat pipe micro-reactor into a heat pipe micro-reactor mechanical model, calculating the mechanical parameters of a matrix supporting the core, and evaluating the structural integrity of the matrix according to the mechanical parameters; and evaluating whether the non-melting requirement of the core is met according to whether the core is damaged and the structural integrity of the matrix.

[0006] Optionally, the accident conditions that may lead to core melting are screened based on probability theory and engineering judgment, including:

[0007] A heat pipe micro-reactor event tree is established, and the occurrence probability of each accident condition is calculated according to the heat pipe micro-reactor event tree; an accident condition with an occurrence probability greater than or equal to a preset probability is regarded as an accident condition that may cause core melting.

[0008] Optionally, the method for establishing a heat pipe micro-reactor event tree includes: screening typical initiating events; establishing a heat pipe micro-reactor event tree based on key safety function requirements, according to the characteristics of the initiating events, and taking into account the accident process; through event tree analysis, defining the final state of the initiating event according to the consequences of radioactive release, and quantifying the probability of occurrence of different final states, and using the probability of occurrence of the final state as the probability of occurrence of the accident condition.

[0009] Optionally, it also includes: judging whether the accident condition with a probability of occurrence less than a preset probability has serious consequences based on engineering knowledge, and if so, considering the accident condition with serious consequences as an accident condition that may cause core melting.

[0010] Optionally, evaluating whether the core is damaged according to the temperature of each component in the heat pipe micro-stack includes: if the temperature of any component in the heat pipe micro-stack exceeds the material temperature limit, then evaluating that the core is damaged.

[0011] Optionally, the material temperature limit is the cladding peak temperature.

[0012] Optionally, the mechanical parameter comprises stress that varies with time.

[0013] Optionally, evaluating the structural integrity of the matrix according to the mechanical parameters includes: when the maximum instantaneous stress exceeds the fracture safety limit of the matrix material, evaluating that the structure of the matrix is ​​incomplete.

[0014] Optionally, evaluating the structural integrity of the matrix according to the mechanical parameters includes: when the long-term stress limit is exceeded under the coupled conditions of temperature, stress and time, evaluating that the structure of the matrix is ​​incomplete.

[0015] Optionally, evaluating whether the core non-melting requirement is met according to whether the core is damaged and the structural integrity of the matrix includes: when the core is not damaged and the structure of the matrix is ​​intact, the core non-melting requirement is met.

[0016] Optionally, the components in the heat pipe micro-stack include fuel cores, cladding, matrix, heat pipes, heat exchangers and reactivity control components.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The core non-meltability evaluation method applicable to heat pipe micro-reactors of the present invention proposes a systematic and comprehensive core non-meltability analysis and evaluation method for the first time for heat pipe micro-reactor design, providing a powerful analysis and demonstration method system for the core non-meltability design of heat pipe micro-reactors; the present invention can effectively screen out accident conditions with low occurrence frequency through probability analysis, significantly reduce the number of accident conditions for deterministic analysis and evaluation, and improve the efficiency of core non-meltability analysis and evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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:

[0020] Figure 1 The present invention is a flowchart of a method for evaluating the inmeltability of a core of a heat pipe micro-reactor according to an embodiment of the present invention.

[0021] Figure 2 yes Figure 1 Flow chart of an embodiment of step S11 in FIG.

[0022] Figure 3 Schematic diagram of an event tree of a heat pipe micro-stack according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] 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.

[0024] Heat pipe micro-reactors refer to nuclear reactors that do not use a coolant loop arrangement for the reactor's primary loop system, but use heat pipes to transfer the heat generated by the core to the secondary loop system or thermoelectric conversion device. In order to support the design and safety analysis of heat pipe micro-reactors to eliminate the possibility of core melting, this patent proposes a heat pipe micro-reactor core non-melting evaluation method.

[0025] Figure 1 FIG. 1 is a flow chart of a method for evaluating the infusibility of a core of a heat pipe micro-reactor according to an embodiment of the present invention. Figure 1 As shown, a core non-melting evaluation method applicable to a heat pipe micro-reactor (hereinafter referred to as a core non-melting evaluation method) 100 includes the following steps:

[0026] Step S11: Screening accident conditions that may lead to core melting based on probability theory and engineering judgment.

[0027] Figure 2 yes Figure 1 Flow chart of step S11 in an embodiment. Figure 2 As shown, step S11 includes:

[0028] Step S111: Establish a heat pipe micro-repile event tree, and calculate the occurrence probability of each accident condition according to the heat pipe micro-repile event tree.

[0029] Event Tree Analysis (ETA) is a method of identifying hazards by inferring possible consequences from the initiating event in the chronological order of the accident. This method uses a tree diagram called an event tree to represent the logical relationship between a certain accident that may occur in the system and the various causes that lead to the accident. Through qualitative and quantitative analysis of the event tree, the main cause of the accident is found, providing a reliable basis for determining safety countermeasures, so as to achieve the purpose of guessing and preventing accidents. The heat pipe micro-reactor event tree is established in the computer.

[0030] Optionally, step S111 is divided into the following three steps:

[0031] The first step is to screen typical initiating events, including but not limited to heat pipe failure and accidental shutdown.

[0032] The second step is to establish a heat pipe micro-reactor event tree based on key safety function requirements such as reactivity control, decay heat removal, and prevention of radioactive release, according to the characteristics of the initiating event and with reasonable consideration of the accident process.

[0033] The third step is to define the final state according to the consequences of radioactive release through event tree analysis, quantify the probability of occurrence of different final states, and use the probability of occurrence of the final state as the probability of occurrence of the accident condition.

[0034] Figure 3 FIG. 1 is a schematic diagram of an event tree of a heat pipe micro-stack according to an embodiment of the present invention. Figure 3 As shown, this embodiment takes the initiating event of an accidental shutdown as an example to establish a heat pipe micro-reactor event tree 300. Among them, accident condition 1 indicates that an accidental shutdown occurs but the residual heat removal system is normal and the stack container is intact. Accident condition 2 indicates that an accidental shutdown occurs, the residual heat removal system fails but the stack container is intact. Accident condition 3 indicates that an accidental shutdown occurs, the residual heat removal system fails and the stack container is damaged. The final state corresponding to accident condition 1 is N3, and N3 indicates that there will be no radioactive leakage. The final state corresponding to accident condition 2 is L1, and L1 indicates that a local radioactive leakage occurs. The final state corresponding to accident condition 3 is L0, and L0 indicates that a large-scale radioactive leakage occurs.

[0035] Assume that the probability of the initiation of an unexpected shutdown is P1, the probability that the residual heat removal system is normal is P2, and the probability that the stack container is intact is P3.

[0036] The calculation results are as follows:

[0037] The probability of occurrence of accident condition 1 is P1*P2*P3;

[0038] The probability of occurrence of accident condition 2 is P1*(1-P2)*P3;

[0039] The probability of occurrence of accident condition 3 is P1*(1-P2)*(1-P3).

[0040] Step S112: An accident condition with an occurrence probability greater than or equal to a preset probability is regarded as an accident condition that may cause core melting.

[0041] Finally, the probability of occurrence of the accident condition is compared with the preset probability, and some accident conditions with very low probability of occurrence are screened out to obtain the recommended accident condition. The preset probability can be 10 -8 / reactor year, the present application does not impose any restrictions on the value of the preset probability. The present invention can effectively screen out accident conditions with low occurrence frequency through probability analysis, significantly reduce the number of accident conditions for deterministic analysis and evaluation, and improve the efficiency of core non-melting analysis and evaluation.

[0042] In some embodiments, the process also includes screening out accident conditions whose probability of occurrence is higher than a preset probability but in which it is determined that core melting will not occur.

[0043] Step S113: Based on the preset engineering knowledge base, the consequence level of the accident condition with a probability of occurrence less than the preset probability is evaluated, and it is determined whether the consequence level reaches the preset level. If so, the accident condition is also regarded as an accident condition that may cause core melting. The consequence level may include low, medium and high levels, and the preset level may be high. The accident condition with a consequence level reaching high level is also regarded as an accident condition that may cause core melting. In short, the accident condition with a small probability of occurrence but serious consequence is also regarded as an accident condition that may cause core melting.

[0044] The above can be understood as judging whether the accident conditions with a probability of occurrence lower than the preset probability have serious consequences. If so, the accident conditions with serious consequences are also regarded as accident conditions that may lead to core melting.

[0045] Step S12: input the accident condition into the heat pipe micro-reactor analysis model, calculate the temperature of each component in the heat pipe micro-reactor under the accident condition, and evaluate whether the core is damaged according to the temperature of each component in the heat pipe micro-reactor.

[0046] In some embodiments, before entering step S12, it also includes establishing a heat pipe micro-pile analysis model. The heat pipe micro-pile analysis model is established using a system analysis program, CFD software, etc. dedicated to the heat pipe micro-pile. The heat pipe micro-pile analysis model covers the main components of the heat pipe micro-pile such as fuel pellets, cladding, matrix, heat pipes, heat exchangers, reactivity control components, etc. The grid nodes of the local area can be subdivided according to different analysis needs, and the temperature of the main components in the heat pipe micro-pile at each time can be better simulated.

[0047] In step S12, the accident conditions selected in step S11 are input into the established heat pipe micro-reactor analysis model, and the temperature of each component in the heat pipe micro-reactor under the accident conditions can be simulated and calculated. The above analysis model is used to carry out deterministic accident consequence analysis, focusing on the accident time process, the temperature rise of core fuel assemblies, matrix and other structures, and to carry out sensitivity analysis of different accident assumptions and model parameters to evaluate the possibility of core temperature rise and melting under various accident conditions.

[0048] Optionally, evaluating whether the core is damaged based on the temperature of each component in the heat pipe micro-reactor includes: if the temperature of any component in the heat pipe micro-reactor exceeds the material temperature limit, the core is evaluated to be damaged. Preferably, the material temperature limit is the cladding peak temperature of 1204°C. The present application takes into account the solid core properties of the heat pipe micro-reactor, and the core damage criterion considers the following aspects:

[0049] According to the heat transfer characteristics of the core, the temperature margin of the fuel pellets is much higher than that of the cladding, and the substrate temperature will not be higher than that of the fuel cladding. Therefore, the criterion for determining core damage in heat pipe micro-reactors is to focus on the maximum temperature of the fuel cladding not exceeding the rapid failure temperature of the cladding material. In probabilistic safety analysis, it is generally emphasized to reflect the actual situation of the power plant or reactor as accurately as possible. For example, the damage of a hot rod in a pressurized water reactor cannot be defined as core damage. The American Society of Mechanical Engineers (ASME) and energy standards also define core damage as oxidation or damage of a certain scale of the core. Similarly, for heat pipe micro-reactors, local cladding temperature exceeding the limit caused by poor contact of the local substrate or failure of a single heat pipe should not be directly defined as core damage. However, heat pipe micro-reactors are different from water reactors. If the local core structure temperature exceeds the limit and continues to operate, it is likely to cause cracking of the core structure, reduce the heat transfer capacity of the structural materials in the nearby area, increase the over-temperature area, and further cause a certain range of cores to lose coolable structures. Therefore, from a conservative point of view, the heat pipe micro-reactor uses the cladding temperature at any point in the entire core exceeding the material temperature limit as the criterion for core damage.

[0050] Step S13: Input the temperature of each component in the heat pipe micro-repile into the heat pipe micro-repile mechanical model, calculate the mechanical parameters of the matrix supporting the core, and evaluate the structural integrity of the matrix based on the mechanical parameters.

[0051] If structural failure such as the matrix occurs under high temperature in a heat pipe micro-reactor, the heat transfer of the fuel assembly will deteriorate sharply. Therefore, it is necessary to conduct a structural integrity assessment of the matrix structure of the heat pipe micro-reactor under high temperature conditions.

[0052] Generally, a finite element analysis software can be used to establish a heat pipe micro-pile mechanical model for the heat pipe micro-pile structure. The temperature of each component in the heat pipe micro-pile obtained in step S12 is input into the heat pipe micro-pile mechanical model to calculate the mechanical parameters of the matrix supporting the core. Optionally, the mechanical parameters include stress on the matrix that changes with time.

[0053] Optionally, evaluating the structural integrity of the matrix according to the mechanical parameters includes: when the maximum instantaneous stress exceeds the fracture safety limit of the matrix material, evaluating that the structure of the matrix is ​​incomplete.

[0054] For the matrix structure, if only the maximum instantaneous stress is considered in an extreme accident, the stress on the matrix may exceed the fracture safety limit and the structural integrity cannot be maintained. Due to the existence of a certain time effect in the temperature rise process, the material's instantaneous stress increase should be alleviated. Simply considering the instantaneous stress is more conservative and extreme. If the time effect is considered, the analysis can be performed according to the long-term stress limit. In view of this, in some embodiments, evaluating the structural integrity of the matrix based on mechanical parameters includes: when the long-term stress limit is exceeded under the coupling conditions of temperature, stress, and time, the structure of the matrix is ​​evaluated to be incomplete.

[0055] Step S14: Evaluate whether the core non-melting requirement is met based on whether the core is damaged and the structural integrity of the matrix.

[0056] When the core is not damaged and the structure of the matrix is ​​intact, the core non-melting requirement is met.

[0057] In some embodiments, it also includes: conducting radioactive consequence analysis for accidents in which the entire stack or part of the fuel cladding is damaged but no fuel core melting occurs, determining the barrier leakage rate applicable to the heat pipe micro-reactor design, analyzing whether the radioactive consequences are acceptable, and providing more comprehensive support for eliminating the conclusion of core melting.

[0058] The core non-meltability evaluation method applicable to the heat pipe micro-reactor of the present invention proposes a systematic and comprehensive core non-meltability analysis and evaluation method for the heat pipe micro-reactor design for the first time, providing a powerful analysis and demonstration method system for the core non-meltability design of the heat pipe micro-reactor; and proposes applicable core damage judgment criteria for the heat pipe micro-reactor, a solid-state reactor model, for the first time, providing a powerful basis for the judgment and evaluation of core damage.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Some aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor may be one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. In addition, various aspects of the present application may be expressed as computer products located in one or more computer-readable media, which include computer-readable program codes. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes ...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs ...), smart cards, and flash memory devices (e.g., cards, sticks, key drives ...).

[0065] A computer-readable medium may include a propagated data signal containing computer program code, such as in baseband or as part of a carrier wave. The propagated signal may have a variety of manifestations, including electromagnetic, optical, etc., or a suitable combination. A computer-readable medium may be any computer-readable medium other than a computer-readable storage medium, which may be connected to an instruction execution system, device or apparatus to communicate, propagate or transmit a program for use. The program code on the computer-readable medium may be propagated via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above mediums.

[0066] 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.

[0067] 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.

[0068] 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 method for evaluating the infusibility of a core of a heat pipe micro-reactor, characterized in that: include: Screening of accident conditions that may lead to core melt based on probability theory and engineering judgment; Inputting the accident condition into a heat pipe micro-reactor analysis model, calculating the temperature of each component in the heat pipe micro-reactor under the accident condition, and evaluating whether the core is damaged according to the temperature of each component in the heat pipe micro-reactor; Inputting the temperature of each component in the heat pipe micro-reactor into a heat pipe micro-reactor mechanical model, calculating the mechanical parameters of a matrix supporting the core, and evaluating the structural integrity of the matrix according to the mechanical parameters; Whether the core non-melting requirement is met is evaluated based on whether the core is damaged and the structural integrity of the matrix.

2. The method according to claim 1, characterized in that The accident conditions that may lead to core melt are screened based on probability theory and engineering judgment, including: Establishing a heat pipe micro-reactor event tree, and calculating the occurrence probability of each accident condition according to the heat pipe micro-reactor event tree; Accident conditions with a probability of occurrence greater than or equal to a preset probability are regarded as accident conditions that may lead to core melting.

3. The method according to claim 1, characterized in that The method of establishing the event tree of heat pipe micro-reactor includes: Screening of typical initiating events; Based on the requirements of key safety functions, according to the characteristics of the initiating event and taking into account the accident process, the event tree of the heat pipe micro reactor is established; Through event tree analysis, the final state of the initiating event is defined according to the consequences of radioactive release, and the probability of occurrence of different final states is quantified, and the probability of occurrence of the final state is used as the probability of occurrence of the accident condition.

4. The method according to claim 2, characterized in that Also includes: The consequence level of an accident condition with a probability less than a preset probability is evaluated based on a preset engineering knowledge base, and it is determined whether the consequence level reaches the preset level. If so, the accident condition is also regarded as an accident condition that may cause core melting.

5. The method according to claim 1, characterized in that Evaluating whether the core is damaged according to the temperature of each component in the heat pipe micro-stack includes: if the temperature of any component in the heat pipe micro-stack exceeds the material temperature limit, the core is evaluated to be damaged.

6. The method according to claim 5, characterized in that The material temperature limit stated is the peak cladding temperature.

7. The method according to claim 1, characterized in that The mechanical parameters include stress that varies with time.

8. The method according to claim 7, characterized in that Evaluating the structural integrity of the matrix according to the mechanical parameters includes: when the maximum instantaneous stress exceeds the fracture safety limit of the matrix material, evaluating that the structure of the matrix is ​​incomplete.

9. The method according to claim 7, characterized in that Evaluating the structural integrity of the matrix according to the mechanical parameters includes: when the long-term stress limit is exceeded under the coupled conditions of temperature, stress and time, evaluating that the structure of the matrix is ​​incomplete.

10. The method according to claim 1, characterized in that The evaluation of whether the core is damaged and the structural integrity of the matrix meets the core non-melting requirement includes: When the core is not damaged and the structure of the matrix is ​​intact, the requirement that the core does not melt is met.

11. The method according to any one of claims 1 to 9, characterized in that: The various components in the heat pipe micro-pile include fuel core blocks, cladding, matrix, heat pipes, heat exchangers and reactivity control components.

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