Heat pipe micro-reactor critical safety analysis method and system

Abstract

The invention provides a heat pipe micro-reactor critical safety analysis method and system. The analysis method comprises the following steps: step 1, determining an application scene of a heat pipe micro-reactor; 2, determining an assumed condition of critical safety analysis based on the target application scene; 3, working condition analysis is conducted on the heat pipe micro-stack in the target application scene according to the assumed conditions; and step 4, calculating an effective increment coefficient based on a working condition analysis result, and adjusting the reactor core structure or the reactor core material when the effective increment coefficient exceeds a limit value. According to the heat pipe micro-reactor critical safety analysis method, the assumed conditions are determined based on different scenes, working condition analysis is carried out under the target scene, and an improvement scheme can be provided for the reactor core structure and the type of the reactor core material according to the analysis result, so that the heat pipe micro-reactor critical safety problem can be accurately evaluated, and an effective solution can be provided.

Description

Technical Field

[0001] The present invention relates to the technical field of critical safety analysis of a heat pipe micro-reactor, and in particular to a critical safety analysis method and system for a heat pipe micro-reactor. Background Art

[0002] The heat pipe micro-reactor can meet the special needs of different application scenarios on land, sea, air and space due to its completely passive, fully static, no coolant loop, simplified system, small size and weight, and flexible operation and deployment. In recent years, it has become a hot topic in micro-reactor research at home and abroad.

[0003] However, due to the mobility of the reactor, the heat pipe micro-reactor brings higher challenges to traditional criticality safety analysis and calculations. Currently, there is no method to accurately evaluate the criticality safety of the heat pipe micro-reactor.

[0004] Based on this, the inventor of the present application proposes a heat pipe micro-reactor critical safety analysis method and system in order to solve the above technical problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of great difficulty in critical safety analysis of heat pipe micro-reactors in the prior art, and to provide a critical safety analysis method and system for heat pipe micro-reactors.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a heat pipe micro-reactor criticality safety analysis method, which is characterized by comprising:

[0008] Step 1, determine the application scenario of the heat pipe micro-stack;

[0009] Step 2: Determine the assumptions for criticality safety analysis based on the target application scenario;

[0010] Step 3: Performing a working condition analysis on the heat pipe micro-stack in the target application scenario according to the assumed conditions;

[0011] Step 4: Calculate the effective incremental coefficient based on the operating condition analysis result, and adjust the core structure or the core material when the effective incremental coefficient exceeds the limit value.

[0012] According to one embodiment of the present invention, in step 1,

[0013] The application scenarios of the heat pipe micro-reactor include on-land vehicle application scenarios and marine application scenarios.

[0014] According to one embodiment of the present invention, in step 2,

[0015] The assumptions include:

[0016] Condition 1: The nuclear fuel is new fuel; Condition 2: The water immersed in the core after the accident is pure water; Condition 3: The temperature reactivity coefficient of the core is negative; Condition 4: After the accident, assuming that the drum limit fails, its position will turn to the same direction under the action of gravity and buoyancy, with the absorber facing upward and the reflector facing downward.

[0017] According to one embodiment of the present invention, in step 3,

[0018] The operating conditions analyzed in the on-land vehicle application scenario include water ingress into the core, failure of the drum limiter, and safety rod detachment from the core;

[0019] The operating conditions analyzed in the marine application scenario include compression of the gaps between fuel assemblies and water ingress due to rupture of heat pipes.

[0020] According to one embodiment of the present invention, the core water inflow condition includes water inflow into the gaps between the fuel assemblies and the gaps between the fuel rods, heat pipes and the fuel grid matrix;

[0021] Under the working condition of the drum limit failure, the drum absorber faces upward and the reflective layer faces downward;

[0022] When the safety rod is out of the core, water will fill the area where the safety rod is located.

[0023] According to one embodiment of the present invention, when the gaps between the fuel assemblies are compressed, the gaps between the core fuel assemblies are squeezed, and the assemblies fit tightly together;

[0024] Under the condition of heat pipe rupture and water inflow, the heat pipe wall breaks and seawater enters the core through the heat pipe.

[0025] According to one embodiment of the present invention, the core structure adjustment method includes one or more combinations of fuel assembly gap adjustment, adding limit switches to the drum, and strengthening the mechanical design of the drive mechanism.

[0026] According to one embodiment of the present invention, the core material adjustment includes adjusting the fuel matrix material to a molybdenum-rhenium alloy.

[0027] The present invention also provides a heat pipe micro-reactor critical safety analysis method, which is characterized in that it is implemented by using the heat pipe micro-reactor critical safety analysis method as described above, and the analysis system includes:

[0028] A determination module, used to determine the application scenario of the heat pipe micro-stack;

[0029] The condition qualification module is used to determine the assumptions of critical safety analysis based on the target application scenario;

[0030] An analysis module, used for performing a working condition analysis of the heat pipe micro-stack in the target application scenario according to the assumed conditions;

[0031] The adjustment module is used to calculate the effective incremental coefficient based on the operating condition analysis result, and adjust the core structure or the core material when the effective incremental coefficient exceeds the limit value.

[0032] The positive and progressive effects of the present invention are:

[0033] The critical safety analysis method of the heat pipe micro-reactor of the present invention determines the assumed conditions based on different scenarios and performs operating condition analysis under the target scenario. According to the analysis results, improvement plans can be proposed for the core structure and the type of core materials. In this way, the critical safety problem of the heat pipe micro-reactor can be accurately evaluated and an effective solution can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0035] Figure 1 This is a flow chart of the critical safety analysis method of the heat pipe micro-reactor of the present invention;

[0036] Figure 2 It is a schematic diagram of the heat pipe micro-reactor core of the present invention;

[0037] Figure 3 Schematic diagram of water ingress into the gaps between fuel assemblies and between fuel rods, heat pipes and fuel grid substrates;

[0038] Figure 4 It is a schematic diagram of the structure of the electronic device of the present invention. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0040] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used in all drawings to represent the same or similar parts. In addition, although the terms used in the present invention are selected from well-known and commonly used terms, some of the terms mentioned in the specification of the present invention 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 the present invention not only by the actual terms used, but also by the meaning implied by each term.

[0041] Critical safety analysis needs to consider different conservative factors to obtain conservative calculation results. The mobility of heat pipe micro reactors brings challenges to traditional critical safety analysis and calculation. The present invention is used to analyze the critical safety conservative factors in land-based vehicle and marine application scenarios.

[0042] Please refer to Figure 1 The present invention proposes a heat pipe micro-reactor criticality safety analysis method, comprising:

[0043] S1. Determine the application scenarios of heat pipe micro-stacks.

[0044] Please refer to Figure 2 The core fuel assembly is composed of multiple hexagonal fuel grid matrixes, with a certain gap between each adjacent matrix. Fuel rods and heat pipes are inserted into the matrix, and a certain gap is left between the fuel rods and heat pipes and the matrix. The core reactivity control is achieved through two methods: the central safety rod and the surrounding control drums, both of which can achieve independent shutdown.

[0045] The application scenarios of the heat pipe micro-reactor of the present invention include on-land vehicle application scenarios and marine application scenarios. Different assumptions for analysis need to be set based on different application scenarios. For example, refer to the following step 2.

[0046] S2. Determine the assumptions for criticality safety analysis based on the target application scenario.

[0047] It can be seen that criticality safety analysis needs to consider different conservative factors to obtain conservative calculation results.

[0048] The assumptions include at least:

[0049] Condition 1: The nuclear fuel is new fuel;

[0050] Condition 2: The water used to immerse the core after the accident is pure water; in different scenarios, seawater can also be used instead.

[0051] Condition three: the core temperature reactivity coefficient is negative; from a conservative point of view, the present invention adopts cold parameters (300K) for analysis.

[0052] Condition 4: After the accident, if the drum limit fails, its position will turn to the same direction under the action of gravity and buoyancy, with the absorber facing upward and the reflective layer facing downward. Specifically, according to the different densities of the absorber and the reflective layer, it can be assumed that the heavy one faces downward and the light one faces upward.

[0053] It can be seen that because the calculation shows that the water layer thickness outside the core has little effect on the calculation results, the present invention takes 5 cm for example calculation. According to different test requirements, 5 cm to 25 cm can also be used, and the water layer thickness is not limited here.

[0054] S3. Perform operating condition analysis of the heat pipe micro-stack in the target application scenario based on assumed conditions.

[0055] The present invention analyzes the working conditions in the on-land vehicle application scenario and the working conditions in the marine application scenario. Different assumptions can be set for the on-land vehicle application scenario and the marine application scenario to meet the test requirements in different scenarios.

[0056] Land-based heat pipe micro-reactors need to consider the requirements for vehicle transportation, as well as the possibility of traffic accidents that may damage the integrity during transportation and the possibility of the reactor module falling into the water.

[0057] The operating conditions that may be encountered in on-land vehicle application scenarios include at least: water ingress into the core, failure of the drum limit, and safety rod detachment from the core.

[0058] like Figure 3 As shown in the figure, in the transport condition, the drum absorber is completely turned toward the core and the safety rod is fully inserted into the core. The core gap water inflow condition mainly includes two aspects: water inflow between the fuel assembly gap and water inflow between the fuel rod, heat pipe and fuel grid matrix. After calculation, the reactivity introduced in the core water inflow condition is 6385PCM.

[0059] It can be seen that reactivity is a parameter that characterizes the degree of deviation of the chain nuclear reaction system from criticality, which can be quantitatively expressed as:

[0060]

[0061] Among them, K eff It represents the effective value-added coefficient and is usually calculated using the six-factor formula.

[0062] Effective value-added coefficient K eff It is the ratio of the number of neutrons in a certain generation to the number of neutrons in the previous generation in the reactor. It is used to reflect the balance between the number of neutrons produced by fission in a self-sustaining chain fission reaction and the number of neutrons lost by non-fission absorption and leakage.

[0063] In order to start the reactor and control the reactor at an appropriate power level, ρ>0 is required. When the power level reaches the specified level, ρ=0 is adjusted and maintained. When the reactor is shut down, ρ<0 must be maintained.

[0064] The main tasks of reactor control are:

[0065] Under the premise of ensuring safety, various effective control methods are adopted to control the residual reactivity of the reactor to meet the needs of long-term operation of the reactor. Through appropriate space layout and the best rod lifting method, the reactor can maintain a relatively flat power distribution throughout the life of the core, making the power peak factor as small as possible. When the external load changes, the reactor power can be adjusted to adapt to the external load changes. When an accident occurs in the reactor, the reactor can be shut down quickly and safely, and the appropriate shutdown depth can be maintained.

[0066] In the event of an accident, the drum limit may also fail. Since the design has taken into account that when the safety rod is inserted into the core, even if all the drum absorbers are turned outside the core, the system can still remain within the subcritical limit. Under the condition of core water inflow, assuming that according to condition 4, the drum absorber is facing up and the reflector is facing down, the introduced reactivity is calculated to be 9559PCM.

[0067] Among them, in the event of an accident, there is a risk that the safety rod will be separated from the core. When water enters the core, the water will fill the area where the safety rod is located. After calculation, the reactivity introduced in this case is 7247PCM.

[0068] Different from the onshore application scenarios, the marine heat pipe micro-reactor needs to be equipped with a pressure chamber to withstand the seawater pressure. In some extreme accidents, the pressure chamber is destroyed or opened in an emergency, which will lead to at least the following two working conditions: the gap between the fuel assemblies is compressed and the heat pipes break and water enters.

[0069] When the safety rod is fully inserted into the core and the drum absorber is turned toward the core, the core is flooded. Under the pressure of seawater, the gaps between the core fuel assemblies will be squeezed out and the fuel assemblies will fit tightly together. After calculation, the reactivity introduced in this case is 3090 PCM.

[0070] When the gaps between fuel assemblies are compressed, since the heat pipe design usually cannot withstand the seawater pressure, in the event of an accident, the heat pipe wall will break and seawater will enter the core through the heat pipe, filling the space originally occupied by the heat pipe. After calculation, the reactivity introduced in this case is 22684PCM.

[0071] S4. Calculate the effective value-added coefficient based on the operating condition analysis results, and adjust the core structure or the core material when the effective value-added coefficient exceeds the limit.

[0072] The calculated effective value-added factor may exceed the statutory or regulatory limit, so the plan can be further adjusted. Common methods include:

[0073] 1. Adjustment of the core structure, including but not limited to: adjustment of the gap between fuel assemblies, addition of limit switches to the drum, and strengthening of the mechanical design of the drive mechanism.

[0074] 2. Adjust the core material, change the fuel matrix and other materials from stainless steel to molybdenum-rhenium alloy, increase the absorption of thermal neutrons and reduce the impact of energy spectrum softening after water ingress.

[0075] The present invention determines assumptions based on different scenarios and performs operating condition analysis under the target scenario. According to the analysis results, improvement plans can be proposed for the core structure and the type of core materials. In this way, the critical safety issues of the heat pipe micro-reactor can be accurately evaluated and effective solutions can be provided.

[0076] The present invention also proposes a heat pipe micro-reactor critical safety analysis system, which is implemented by using the above heat pipe micro-reactor critical safety analysis method. The analysis system includes:

[0077] A determination module, used to determine the application scenario of the heat pipe micro-stack;

[0078] The condition qualification module is used to determine the assumptions of critical safety analysis based on the target application scenario;

[0079] An analysis module is used to analyze the operating conditions of the heat pipe micro-stack in the target application scenario based on assumed conditions;

[0080] The adjustment module is used to calculate the effective value-added coefficient based on the operating condition analysis results, and to adjust the core structure or the core material when the effective value-added coefficient exceeds the limit.

[0081] Reference Figure 4 The present invention also provides an electronic device 900, including: a processor 901 and a memory 902, the memory 902 stores a program or instruction that can be run on the processor 901, and the program or instruction is executed by the processor 901 to perform the above-mentioned heat pipe micro-reactor critical safety analysis method. When the program or instruction is executed by the processor 901, each process of the implementation method of the above-mentioned heat pipe micro-reactor critical safety analysis method is implemented, and the same technical effect can be achieved. In order to avoid repetition, it will not be repeated here.

[0082] The present invention also provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the above-mentioned heat pipe micro-reactor critical safety analysis method is implemented. When the program or instruction is executed by the processor, each process of the implementation method of the above-mentioned heat pipe micro-reactor critical safety analysis method is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0083] 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 implementation of the present application.

[0084] 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, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0085] 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 ...).

[0086] 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.

[0087] Similarly, it should be noted that in order to simplify the description disclosed in this application, so as to help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawings or descriptions thereof. However, this disclosure method does not mean that the features required by the object of the present application are more than the features mentioned in the claims. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above. 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 "approximately", "approximately" or "substantially" in some examples. Unless otherwise specified, "approximately", "approximately" or "substantially" indicate that the number allows a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining the 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, such numerical settings are as accurate as possible within the feasible range.

[0088] Although the present invention is disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A heat pipe micro-reactor criticality safety analysis method, characterized in that: include: Step 1, determine the application scenario of the heat pipe micro-stack; Step 2: Determine the assumptions for criticality safety analysis based on the target application scenario; Step 3: Performing a working condition analysis on the heat pipe micro-stack in the target application scenario according to the assumed conditions; Step 4: Calculate the effective incremental coefficient based on the operating condition analysis result, and adjust the core structure or the core material when the effective incremental coefficient exceeds the limit value.

2. The heat pipe micro-reactor criticality safety analysis method according to claim 1, characterized in that: In the step 1, The application scenarios of the heat pipe micro-reactor include on-land vehicle application scenarios and marine application scenarios.

3. The heat pipe micro-reactor criticality safety analysis method according to claim 2, characterized in that: In the step 2, The assumptions include: Condition 1: The nuclear fuel is new fuel; Condition 2: The water immersed in the core after the accident is pure water; Condition 3: The temperature reactivity coefficient of the core is negative; Condition 4: After the accident, assuming that the drum limit fails, its position will turn to the same direction under the action of gravity and buoyancy, with the absorber facing upward and the reflector facing downward.

4. The heat pipe micro-reactor criticality safety analysis method according to claim 2, characterized in that: In step 3, The operating conditions analyzed in the on-land vehicle application scenario include water ingress into the core, failure of the drum limiter, and safety rod detachment from the core; The operating conditions analyzed in the marine application scenario include compression of the gaps between fuel assemblies and water ingress due to rupture of heat pipes.

5. The heat pipe micro-reactor criticality safety analysis method according to claim 4, characterized in that: The core water inflow condition includes water inflow into the gaps between the fuel assemblies and between the fuel rods, heat pipes and the fuel grid matrix; Under the working condition of the drum limit failure, the drum absorber faces upward and the reflective layer faces downward; When the safety rod is out of the core, water will fill the area where the safety rod is located.

6. The heat pipe micro-reactor criticality safety analysis method according to claim 4, characterized in that: Under the condition where the gaps between the fuel assemblies are compressed, the gaps between the core fuel assemblies are squeezed, and the assemblies fit tightly together; Under the condition of heat pipe rupture and water inflow, the heat pipe wall breaks and seawater enters the core through the heat pipe.

7. The heat pipe micro-reactor criticality safety analysis method according to claim 1, characterized in that: The core structure adjustment method includes one or more combinations of fuel assembly gap adjustment, adding limit switches to the drum, and strengthening the mechanical design of the drive mechanism.

8. The heat pipe micro-reactor criticality safety analysis method according to claim 1, characterized in that: The core material adjustment includes adjusting the fuel matrix material to a molybdenum-rhenium alloy.

9. A heat pipe micro-reactor criticality safety analysis system, characterized in that: The critical safety analysis method of a heat pipe micro-reactor according to any one of claims 1 to 8 is used, and the analysis system comprises: A determination module, used to determine the application scenario of the heat pipe micro-stack; The condition qualification module is used to determine the assumptions of critical safety analysis based on the target application scenario; An analysis module, used for performing a working condition analysis of the heat pipe micro-stack in the target application scenario according to the assumed conditions; The adjustment module is used to calculate the effective incremental coefficient based on the operating condition analysis result, and adjust the core structure or the core material when the effective incremental coefficient exceeds the limit value.

10. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and the programs or instructions are executed by the processor to implement the heat pipe micro-reactor critical safety analysis method as described in any one of claims 1 to 8.

11. A readable storage medium, characterized in that: The readable storage medium stores programs or instructions, and when the programs or instructions are executed by the processor, the critical safety analysis method for a heat pipe micro-reactor as described in any one of claims 1 to 8 is implemented.

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