Solid core temperature field reconstruction verification system and method

Abstract

This application provides a solid-state reactor core temperature field reconstruction verification system and method. The verification system includes a simulated reactor core subsystem, comprising: a test substrate, multiple electric heating rods embedded in the test substrate, and multiple test heat pipes; the axial length of the test substrate is less than the axial length of the actual substrate, and the test heat pipes include an evaporation section, an adiabatic section, and a condensation section. The evaporation section has the same axial length as the test substrate and is fixed in position, while the length of the condensation section is adjustable; the length of the heating section of the electric heating rods is adjustable; a cooling subsystem includes at least one adjustable cooling medium circulation loop, which is connected to the condensation section of the test heat pipes to equivalently simulate the heat sink boundary of the solid-state reactor core; and a data acquisition and control subsystem, connected to the electric heating rods and the cooling subsystem respectively, for adjusting the heating power of the electric heating rods according to preset operating conditions and changing the cooling capacity of the cooling subsystem by adjusting the adjustable parameters of the cooling medium circulation loop.

Description

Technical Field

[0001] This application mainly relates to the field of nuclear reactor thermal-hydraulic and safety monitoring technology, and in particular to a solid core temperature field reconstruction verification system and method. Background Technology

[0002] In the field of nuclear energy, especially in solid-state reactor systems such as heat pipe microreactors, the core temperature field is a key physical quantity characterizing the core's thermal state and safety margin. However, due to the highly compact structure of solid-state reactor cores, the dense arrangement of internal components, and the high operating temperature and limited space, the number of temperature measurement points that can be deployed in practical engineering is very limited. Typically, only a small amount of discrete temperature information can be obtained from local locations, making it difficult to directly obtain a complete and continuous three-dimensional temperature field distribution within the core. This contradiction between "sparse measurement points" and "continuous temperature field distribution" makes it difficult to meet the needs of core condition awareness and safety assessment by relying solely on direct measurement methods.

[0003] To address the aforementioned issues, various methods for reconstructing the temperature field of solid reactor cores have been developed in recent years. These methods, using limited temperature measurement data combined with physical or data-driven models, infer and reconstruct the overall temperature field of the reactor core. These approaches provide a feasible technical path for obtaining the internal temperature distribution of the reactor core under limited measurement conditions, and have significant application potential in core condition monitoring, anomaly early warning, and accident analysis.

[0004] However, the application of temperature field reconstruction methods to practical engineering systems requires thorough verification of the methods' accuracy and reliability. Currently, the verification of temperature field reconstruction methods largely relies on numerical simulation results, typically comparing the reconstructed temperature field with the numerical simulations from Computational Fluid Dynamics (CFD) simulations. However, these results are insufficient to provide a sufficient basis for engineering applicability.

[0005] Experimental verification based on real physical systems can more directly reflect the actual thermal behavior of the reactor core, and is especially representative under complex operating conditions. However, how to construct an experimental system under laboratory conditions that is both safe and controllable, and can equivalently reproduce various operating and abnormal conditions of the actual reactor core, is a current technical challenge. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide a solid core temperature field reconstruction verification system and method to solve the problem that existing solid core temperature field reconstruction methods lack systematic experimental verification methods based on real physical systems, which makes it difficult to reliably evaluate their engineering applicability.

[0007] To address the aforementioned technical problems, this application provides a solid-state reactor core temperature field reconfiguration verification system, comprising:

[0008] The simulated reactor core subsystem includes: a test substrate, multiple electric heating rods embedded in the test substrate, and multiple test heat pipes; the axial length of the test substrate is less than the axial length of the actual substrate, the test heat pipes include an evaporation section, an adiabatic section, and a condensation section, the evaporation section has the same axial length as the test substrate and is fixed in position, the length of the condensation section is adjustable; the length of the heating section of the electric heating rods is adjustable;

[0009] The cooling subsystem includes at least one adjustable cooling medium circulation loop, which is connected to the condensation section of the test heat pipe to simulate the heat sink boundary of a solid reactor core.

[0010] The data acquisition and control subsystem is connected to the electric heating rod and the cooling subsystem respectively. It is used to adjust the heating power of the electric heating rod according to the preset working conditions, and to change the cooling capacity of the cooling subsystem by adjusting the adjustable parameters of the cooling medium circulation loop. At the same time, it collects the temperature data measured by the temperature sensors arranged at key positions of the test substrate, the electric heating rod, and the test heat pipe.

[0011] Optionally, the data acquisition and control subsystem is configured to: determine the axial scaling factor based on the ratio of the axial length of the test substrate to the axial length of the actual substrate; calculate the target total power of the test based on the axial scaling factor and the actual total power of the solid core; and control the sum of the heating power of all electric heating rods to be equal to the target total power of the test.

[0012] Optionally, the data acquisition and control subsystem is further configured to: determine the volumetric power density required to be achieved by the electric heating rod; and determine the heating section length of the electric heating rod based on the total test target power, the volumetric power density, the number of electric heating rods, and the cross-sectional area of ​​the electric heating rods.

[0013] Optionally, the cooling medium circulation loop includes: a compressor, an electric valve, a mass flow meter, and a heat exchanger connected in sequence. The condensing section of the test heat pipe is inserted into the interior of the heat exchanger. The compressor and the electric valve cooperate to regulate the gas flow rate, thereby regulating the heat transfer coefficient of the condensing section of the test heat pipe.

[0014] Optionally, the data acquisition and control subsystem is configured to: determine the design heat capacity of a single test heat pipe based on the total power of the test target and the number of test heat pipes; and match the heat transfer capacity of the condensing section of the test heat pipe with the design heat capacity by adjusting the length of the condensing section and / or the heat transfer coefficient of the condensing section of the test heat pipe.

[0015] Optionally, the data acquisition and control subsystem is configured to: acquire the response curve of temperature change over time at key measuring points during the test, and calculate the time constant of the simulated core subsystem based on the temperature response curve; compare the time constant of the simulated core subsystem with the time constant of the solid core, and adjust the condensation section length of the test heat pipe and / or the heat transfer coefficient of the condensation section of the test heat pipe according to the comparison result, and iteratively adjust the time constant of the simulated core subsystem until the time constant of the simulated core subsystem matches the time constant of the solid core.

[0016] Optionally, the data acquisition and control subsystem is further configured to: when the time constant of the simulated core subsystem and the time constant of the solid core cannot be strictly equal, establish a time mapping relationship so that the temperature response curve of the simulated core subsystem corresponds to the temperature response curve of the solid core through time coordinate transformation.

[0017] Optionally, it further includes: a heat pipe failure simulation device, the heat pipe failure simulation device comprising: a vent valve assembly disposed at the bottom end of the test heat pipe, used to remain closed under normal operating conditions to maintain the sealing of the test heat pipe, and to open when it is necessary to simulate failure conditions to release the sodium working fluid inside the test heat pipe; a vent pipe connected to the vent valve assembly; a throttling and metering unit disposed in the vent pipe for adjusting and monitoring the leakage rate of the sodium working fluid; and a sodium collection box connected to the vent pipe for collecting the leaked sodium working fluid, the interior of which is a vacuum environment or filled with an inert gas environment.

[0018] To address the aforementioned technical problems, this application provides a method for verifying solid-state reactor core temperature field reconstruction using the system described in this application. The method includes: conducting various operating conditions and abnormal operating conditions tests on the solid-state reactor core temperature field reconstruction verification system; acquiring full-field measured temperature data reflecting the actual temperature response through the temperature sensor; extracting a sparse measurement point dataset from the full-field measured temperature data, corresponding to the actual number and location of measurement points in the solid-state reactor core; inputting the sparse measurement point dataset into the solid-state reactor core temperature field reconstruction method to be verified, obtaining the reconstructed reactor core temperature field; using the full-field measured temperature data as a verification benchmark, comparing and analyzing the reconstructed reactor core temperature field to evaluate the prediction accuracy and robustness of the solid-state reactor core temperature field reconstruction method.

[0019] Optionally, the various operating conditions and abnormal operating conditions include one or more of the following: rated power operation, power variation operation, local cooling capacity degradation operation, and single or multiple test heat pipe failure operation.

[0020] Optionally, the simulated reactor core subsystem and the solid reactor core satisfy a physical equivalence relationship in terms of heat source distribution, heat conduction path, heat dissipation channel, heat sink boundary and dynamic temperature response.

[0021] Compared with the prior art, this application has the following advantages:

[0022] The solid-state reactor core temperature field reconfiguration verification system of this application elevates the verification benchmark of the temperature field reconfiguration method from numerical simulation to physical measurement by constructing a simulated reactor core subsystem that satisfies multi-level physical equivalence relationships with the solid-state reactor core. This overcomes the limitations of the traditional "simulation-to-simulation verification" approach. Key parameters such as the length and power of the electric heating rod, the length of the experimental heat pipe condensation section, and cooling conditions are all adjustable, enabling the same experimental system to cover different reactor design parameters or different operating conditions. This provides an engineering-grade experimental verification platform for the reconfiguration method, significantly improving the reliability and engineering applicability of the verification results. Attached Figure Description

[0023] The accompanying drawings are included to provide a further understanding of this application. They are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application.

[0024] Figure 1 This is a schematic diagram of a solid core temperature field reconstruction verification system according to an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the structure of an electric heating rod according to an embodiment of this application.

[0026] Figure 3 This is a schematic diagram of the structure of an experimental heat pipe according to an embodiment of this application.

[0027] Figure 4 This is a schematic diagram of the arrangement of temperature sensors according to an embodiment of this application.

[0028] Figure 5 This is a schematic diagram of a heat pipe failure simulation device according to an embodiment of this application.

[0029] Figure 6 This is a flowchart of a solid core temperature field reconstruction verification method according to an embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0031] Figure 1 This is a schematic diagram of a solid-state reactor core temperature field reconfiguration verification system according to an embodiment of this application. Figure 1 As shown, the solid reactor core temperature field reconstruction verification system includes a simulated core subsystem, a cooling subsystem, and a data acquisition and control subsystem. The simulated core subsystem includes an electric heating rod control cabinet 1, electrical control cables 2, electric heating rods 3, a test substrate 4, and test heat pipes 5. The test substrate 4 is made of a metallic material (such as stainless steel or a high-temperature alloy) with the same thermophysical properties as the actual solid reactor core substrate material, and its radial geometry and arrangement are consistent with a single solid reactor core component. The test substrate 4 has precisely arranged channels for embedding the electric heating rods 3 and the test heat pipes 5. The axial length of the test substrate 4 is less than the axial length of the actual solid reactor core substrate to achieve axial scaling.

[0032] An electric heating rod 3 is embedded within the pores of the test substrate 4 to simulate the heat release of a fuel rod. For example... Figure 2 As shown, the electric heating rod includes a heating section 31 and an adjustable length section 32 connected to the heating section. The length of the heating section 31 is adjustable, and the adjustable length section 32 is used to adjust the axial position of the heating section within the test substrate. Optionally, a limiting structure 33 can be provided between the heating section 31 and the adjustable length section 32. The limiting structure 33 is used to ensure the axial positioning accuracy and radial alignment of the heating section within the test substrate.

[0033] The experimental heat pipe 5 is embedded within the pores of the experimental substrate 4 to simulate the heat dissipation channels of a solid-state reactor core. For example... Figure 3 As shown, the test heat pipe 5 includes an evaporation section 51, an adiabatic section 52, and a condensation section 53. The evaporation section 51 has the same axial length as the test substrate 4 and is fixed in position, ensuring complete coupling between the evaporation section and the test substrate. The condensation section 53 is entirely located inside the heat exchanger in the cooling subsystem. The length of the condensation section 53 is adjustable, and the length of the adiabatic section can also be adjusted as needed to regulate the heat dissipation capacity of the test heat pipe without changing the coupling relationship between the evaporation section and the test substrate. Optionally, the total length of the test heat pipe 5 is adjustable; by adjusting the length distribution between the adiabatic section 52 and the condensation section 53, different external heat transfer distances and condensation areas can be simulated.

[0034] The cooling subsystem is connected to the condensation section of the experimental heat pipe to simulate the heat sink boundary of a solid reactor core. The cooling subsystem includes at least one adjustable cooling medium circulation loop. Figure 1As shown, the cooling medium circulation loop includes a gas loop and a cooling water loop. The gas loop and the cooling water loop are coupled through a heat exchanger 6. The condenser section of the test heat pipe is inserted into the heat exchanger 6. The gas loop includes an air filter 7, a compressor 8, an electric valve 9, and a mass flow meter 10 connected in sequence. The air filter 7 ensures gas cleanliness, the compressor 8 provides power to the gas, and the electric valve 9 and the mass flow meter 10 together regulate and measure the gas flow rate.

[0035] Optionally, a pressure transmitter 11 and a temperature transmitter 12 are also included between the mass flow meter 10 and the heat exchanger 6. The pressure transmitter 11 and the temperature transmitter 12 are used to monitor key parameters in real time, and adjust the gas flow rate by controlling the operation of the compressor 8 and the electric valve 9, thereby adjusting the heat transfer coefficient of the condensing section of the test heat pipe, so as to reliably simulate the heat sink conditions of the actual reactor core.

[0036] like Figure 1 As shown, the cooling water circuit includes a cooling water tank 15, a chiller inlet manual valve 16, a chiller outlet manual valve 17, and a chiller 18. It provides secondary cooling for the gas circuit, ensuring its continuous heat dissipation capacity. Optionally, the cooling water circuit also includes a silencer 19 to reduce operating noise. The cooling water circuit operates as follows: chilled water from the chiller 18 enters the cooling water tank 15 via the chiller inlet manual valve 16. The hot air discharged from the heat exchanger 6 is cooled by the chilled water in the cooling water tank 15. The cooled air enters the silencer 19 and is finally discharged from the atmospheric heat trap. The heated water in the cooling water tank 15 flows back to the chiller 18 via the chiller outlet manual valve 17.

[0037] The data acquisition and control subsystem is connected to the electric heating rod and the cooling subsystem respectively. It is used to adjust the heating power of the electric heating rod according to the preset working conditions, and to change the cooling capacity of the cooling subsystem by adjusting the adjustable parameters of the cooling medium circulation loop. At the same time, it collects the temperature data measured by the temperature sensors arranged at key positions of the test substrate, electric heating rod and test heat pipe.

[0038] Temperature sensors, such as thermocouple networks or distributed fiber optic sensors, are arranged at a density far exceeding that of actual reactors to acquire full-field temperature distribution data as a verification benchmark. For example... Figure 2 and Figure 4As shown, the temperature sensor mainly collects key temperature data from three test components: the inner wall of the measurement through-hole, the wall of the electric heating rod, and the wall of the test heat pipe. For a single measurement through-hole, there are five equally spaced temperature measurement points: measurement point P1, measurement point P2, measurement point P3, measurement point P4, and measurement point P5, all located on the inner wall of the measurement through-hole near the center of the simulated reactor core. For a single electric heating rod, there is a second measurement point P7 in the middle, and measurement points P6 and P8 near its two ends, respectively. For a single test heat pipe, there are two measurement points: the first measurement point P9 at the top of the evaporation section and the second measurement point P10 at the top of the condensation section. All the temperature measurement data from these points together constitute the test temperature data, used for experimental verification.

[0039] The solid-state reactor core temperature field reconstruction verification system of this application uses an actual solid-state reactor single component as a prototype. By establishing clear physical equivalence relationships at multiple levels such as geometric structure, heat source distribution, heat dissipation channels, heat sink boundaries and dynamic temperature response, it can equivalently reproduce the thermal behavior of the actual reactor core under different operating and abnormal conditions in the laboratory. This provides a systematic experimental verification means for the accuracy, reliability and accident diagnosis capability of the temperature field reconstruction method.

[0040] First, in terms of geometry, the test substrate 4 of this application maintains the same through-hole arrangement as the actual substrate of a solid reactor core. Specifically, the number of electric heating rods inserted into the test substrate 4 equals the number of fuel rods in the actual substrate, and the number of test heat pipes inserted into the test substrate 4 equals the number of heat pipes in the actual substrate. The outer diameter of the electric heating rods is the same as the outer diameter of the test heat pipes. This consistency ensures that the radial heat conduction path between the electric heating rods, the test substrate, and the test heat pipes is consistent with the thermal resistance network topology.

[0041] In this application, the axial length of the test substrate It is fixed; the evaporation section of the test heat pipe is inserted into the test substrate and is at the same height as the test substrate, therefore the length of the evaporation section is... .

[0042] The total length of the heat pipe is adjustable, and the length of the insulation section is also adjustable. With the length of the condensation section Since these are also adjustable parameters, the test heat pipes in the experiment have the following length relationships:

[0043]

[0044] in, The total length of the heat pipe being tested. This is the length of the evaporation section.

[0045] The length and position of the heating section of the electric heating rod are adjustable, and the electric heating rod is located in the hole of the test substrate and is arranged axially in the center. That is, its heating section is symmetrically distributed in the middle of the test substrate, which is equivalent to the working condition of the actual fuel section being arranged in the center.

[0046] This embodiment uses a certain type of solid reactor core as a prototype to explain in detail the process of establishing the physical equivalence relationship of heat source distribution.

[0047] The actual parameters of the target solid-state reactor core are as follows: axial length of the actual matrix. Actual fuel rod length It is located in the middle of the matrix, with a 0.175 m cavity section at each end. Number of fuel rods. fuel rod diameter fuel rod cross-sectional area fuel rod volumetric power density Actual total power 45.07 kW.

[0048] First, the axial length of the test substrate is selected based on laboratory space and manufacturing costs. Calculate the axial scaling factor .

[0049] Secondly, the total target power of the test is calculated based on the axial scaling factor. Calculate The data acquisition and control subsystem controls the total heating power of all electric heating rods to be equal to 14.54 kW.

[0050] Finally, based on the total target power, the number of electric heating rods, and the cross-sectional area of ​​the electric heating rods, the required volumetric power density of the electric heating rods is calculated. The number of electric heating rods is equal to the number of fuel rods. The cross-sectional area of ​​the electric heating rod is equal to the cross-sectional area of ​​the fuel rod. Alternatively, it can be calculated using the following formula:

[0051]

[0052] in, The required volumetric power density for the electric heating rod. This refers to the length of the heating section of the electric heating rod. This is to maximize the actual volumetric power density of the electric heating rod. With fuel rod volumetric power density By matching the parameters, the length of the heating section of the electric heating rod can be calculated. = 0.3871 m. Therefore, by adjusting the length of the heating rod to 0.387 m and arranging it in the center, the volumetric power density of the fuel rod can be directly made consistent with the actual value in the experiment, while satisfying the equivalence of the total power reduction ratio.

[0053] In summary, the total experimental power and heating rod length were derived from the equivalent power density of the fuel rod, ultimately resulting in a unified expression for the equivalent heat source, i.e., with the base length fixed at a certain value. Under the condition that the heating section length of the electric heating rod is adjustable, the test heat source can be equivalently transmitted through... A unified description. Specifically, when the length of the heating section of the electric heating rod... When arranged in the center, make This allows for simultaneous equivalence of heat source intensity and axial distribution.

[0054] Based on the above-determined total test target power ≈ 14.54 kW. The following explains the process of establishing the physical equivalence between the heat dissipation channel and the heat sink boundary.

[0055] First, the design heat capacity of a single test heat pipe is determined based on the total target power and the number of test heat pipes. (Number of test heat pipes) Assuming the power carried away by the heat pipe is β ≈ 1, then the design heat capacity of a single experimental heat pipe is... The heat capacity of a single experimental heat pipe was calculated. .

[0056] Secondly, the length of the evaporation section of the experimental heat pipe is equal to the length of the experimental substrate, i.e., Lev,e = 0.5 m. Therefore, the heat absorbed per unit length of the evaporation section is... This parameter is directly related to the heat flux density of the evaporation section of the heat pipe and is an important basis for heat pipe selection.

[0057] Then, by adjusting the length of the condenser section of the test heat pipe and / or the heat transfer coefficient between the condenser section and the cooling medium, the actual heat transfer of the test heat pipe is matched with the designed heat transfer capacity. The heat transfer in the condenser section of the test heat pipe satisfies:

[0058]

[0059] Among them, when Given the allowable temperature difference, the lower limit of the condensation section length is: The required heat transfer coefficient can be derived from this. .

[0060] Because the total length of the heat pipe is adjustable: ,and Since the length is fixed at 0.5 m, the length of the condensation section can be increased by increasing the total length or shortening the adiabatic section within a given total length, thereby reducing convective thermal resistance and improving heat dissipation capacity. This allows for increased condensation section length even under the constraint of "fixed substrate and evaporation section". , , Three adjustable parameters enable equivalent or dynamic matching of the heat sink.

[0061] If take Then the length of the heat pipe condenser section .

[0062] If take Then the length of the heat pipe condenser section .

[0063] Optionally, under heat sink conditions and equivalent load (approximately 765W per pipe), the preferred range for the length of the heat pipe's insulation section is: = 0.05 - 0.15 m, the length range of the condensation section is = 0.50 - 0.70 m.

[0064] More preferably, the length of the condensation section is Insulation section length Total length The heat pipes were tested. Correspondingly, the actual temperature difference requirement for each working section of this heat pipe is... Therefore, the outer wall of the condensation section only needs to be approximately higher than the incoming flow. This is a very reasonable way to dissipate 765W of heat.

[0065] The following section further explains the process of establishing the physical equivalence relationship for the dynamic temperature response. The data acquisition and control subsystem is configured as follows:

[0066] The response curves of temperature change over time at key measuring points during the experiment are obtained, and the time constant of the simulated reactor core subsystem is calculated based on the temperature response curves.

[0067] Under an engineering-acceptable first-order dominant approximation, the temperature response at key measuring points can be described by an equivalent heat capacity-equivalent thermal resistance model, and its governing equation can be expressed as:

[0068]

[0069] in, Indicates the key measurement points in time temperature, This indicates the incoming flow temperature of the external heat sink. Indicates the time of the electric heating rod Total thermal power input; Equivalent heat capacity represents the combined heat capacity of components such as the electric heating rod, the test substrate, and the local structure of the heat pipe that participate in heat storage during the transient process; Equivalent thermal resistance represents the overall heat transfer resistance exhibited throughout the entire process of heat transfer from the heat source location through heat conduction in the test substrate, heat absorption in the evaporation section of the heat pipe, heat transport within the heat pipe, and finally dissipation to the external heat trap through the condensation section.

[0070] As can be seen from the above model, the speed of the system's temperature response can be determined by the time constant. Characterization is performed, where the time constant is... This represents the characteristic time scale required for the system temperature to complete its main change under disturbance. A larger time constant indicates a slower temperature response; a smaller time constant indicates a faster temperature response. To ensure that the experimental system and the actual system have the same temperature response speed under the same type of disturbance, i.e., satisfying the time constant requirement, is crucial. In a preferred embodiment, through proper design, the overall heat transfer process of the system can be mainly controlled by the convective heat transfer of the heat pipe condensation section, and the convective heat transfer thermal resistance of the condensation section is minimized. It can be represented as:

[0071]

[0072] in, The heat transfer coefficient of the condenser section of the test heat pipe is given. This refers to the length of the condenser section of the heat pipe being tested.

[0073] At this point, it can be approximated that... Under these conditions, the length of the condenser section of the test heat pipe was adjusted. And / or the heat transfer coefficient of the condensing section of the test heat pipe The time constant of the simulated reactor core subsystem Iterative adjustments are made until the time constant of the simulated reactor core subsystem is reached. The time constant of the solid core Matching.

[0074] Optionally, when the time constants of the test system and the solid reactor core cannot be strictly equal, the data acquisition and control subsystem establishes a time mapping relationship. This allows the temperature response curve of the test system to correspond to the temperature response curve of the solid reactor core through time coordinate transformation.

[0075] In the temperature field reconstruction verification test of this application, in addition to normal operation conditions and heat sink change conditions, a heat pipe failure equivalent method based on controllable leakage of sodium working fluid and its test device are further proposed to simulate the degradation or loss of heat dissipation capacity of high-temperature sodium heat pipes in actual reactor systems due to working fluid leakage, insufficient working fluid inventory or internal cavity failure, thereby realizing the effective verification of the temperature field reconstruction method in accident diagnosis scenarios.

[0076] In practical reactor systems, typical failure mechanisms of high-temperature sodium heat pipes include, but are not limited to: slow leakage of sodium working fluid caused by microcracks in the heat pipe shell, vacuum disruption due to seal failure, and the resulting interruption of two-phase circulation. A common characteristic of these failure mechanisms is the reduction in the effective working fluid mass inside the heat pipe, leading to a significant decrease in its equivalent heat transfer capacity, causing the heat pipe to degenerate from a highly efficient heat dissipation channel into an inefficient channel relying solely on heat conduction from the metal shell. Based on this physical essence, this application uses "heat transfer capacity attenuation caused by sodium working fluid leakage" as the equivalent object of heat pipe failure conditions.

[0077] To achieve the above equivalence, this application designs a heat pipe failure simulation device. For example... Figure 5 As shown, the heat pipe failure simulation device includes: a sodium heat pipe 20, a vent valve assembly 21 disposed at the bottom end of the sodium heat pipe, a vent pipe 22 connected to the vent valve assembly, a throttling and metering unit 23 disposed in the vent pipe, and a vacuum or inert gas sodium collection box 24 connected to the vent pipe. The evaporation section of the sodium heat pipe 20 is arranged inside the test substrate. The vent valve assembly 21 remains closed under normal operating conditions to maintain the sealing of the sodium heat pipe, and can be opened to release the sodium working fluid inside the sodium heat pipe when it is necessary to simulate failure conditions. The vent valve assembly is preferably an adjustable valve, and its opening degree is adjustable.

[0078] The venting line 22 is used to guide the safe discharge of sodium working fluid during failure simulation. The throttling and metering unit 23, which can be in the form of an orifice plate, adjustable valve, or mass flow meter, is used to control and monitor the leakage rate of sodium working fluid, thereby achieving continuous adjustment of the heat pipe failure level. The sodium collection box 24 is a sealed structure, maintaining a vacuum environment or filled with inert gas inside to avoid the risk of chemical reactions caused by contact between sodium working fluid and air or water, and also serves as a safe collection chamber for leaked sodium. The sodium collection box 24 is equipped with a vacuum or inert gas filling interface 241, as well as a pressure sensor 25 and a temperature sensor 26 for real-time monitoring of the internal environment.

[0079] In the specific experimental process, when it is necessary to simulate the planned failure of a heat pipe, the test system is first stabilized at the set power level and thermal equilibrium is reached. Then, while keeping other heat pipes and operating parameters unchanged, the vent valve assembly 21 is opened through the data acquisition and control subsystem, allowing the sodium working fluid in the sodium heat pipe to enter the sodium collection box 24 through the vent pipe 22. As the working fluid leaks, the two-phase circulation inside the heat pipe is gradually blocked, and its equivalent heat transfer capacity decreases continuously as the working fluid inventory decreases, thus forming a temperature response characteristic inside the simulated reactor core that is consistent with the sodium heat pipe leakage failure in an actual reactor.

[0080] By adjusting the opening degree of the relief valve assembly 21 or the parameters of the throttling and metering unit 23, equivalent simulations of different failure mode degrees can be achieved:

[0081] Slow leakage condition: This refers to a failure scenario where the heat transfer capacity of the heat pipe gradually decreases.

[0082] Rapid leakage condition: This refers to a sudden failure situation in which the heat transfer capacity of the heat pipe decreases significantly in a short period of time.

[0083] Partial leakage condition: This refers to a partial failure where the heat pipe still retains limited heat dissipation capacity.

[0084] Complete leakage condition: This refers to a complete failure situation where the heat pipe's heat transfer capacity is almost completely lost.

[0085] When leakage reaches a preset threshold, the heat pipe can be determined to have "failed." This threshold can be defined based on one or more criteria, such as the proportion of leaked sodium mass, the percentage decrease in the heat pipe's equivalent heat transfer capacity, or the temperature rise at the evaporation section or adjacent measuring points exceeding a preset value. By collecting temperature response data from the failed heat pipe and its surrounding electric heating rod measuring points, the accuracy and reliability of the temperature field reconstruction method in identifying the heat pipe failure location, determining the degree of failure, and predicting the temperature field under accident conditions can be verified.

[0086] This application also provides a method for verifying the temperature field reconstruction of a solid-state reactor core using the system described in this application, such as... Figure 6 As shown, the method includes:

[0087] Step S61: Conduct various operating conditions and abnormal operating conditions tests on the solid core temperature field reconstruction verification system, and obtain full-field measured temperature data reflecting the real temperature response through temperature sensors.

[0088] Among them, the solid core temperature field reconstruction verification system is equivalent to the solid core in multiple aspects such as heat source distribution, heat conduction path, heat dissipation channel, heat sink boundary and dynamic temperature response.

[0089] Conduct tests under various operating conditions and abnormal operating conditions, including:

[0090] Normal operating conditions: Rated power operation, acquiring steady-state temperature field reference data;

[0091] Power variation conditions: step increase or ramp change of heating power to simulate reactive accidents;

[0092] Localized cooling capacity degradation condition: By adjusting the parameters of the cooling subsystem, the heat dissipation capacity of a specific heat pipe is reduced;

[0093] Heat pipe failure conditions: A heat pipe failure simulation device is used to simulate the complete or partial failure of a single or multiple test heat pipes.

[0094] During the experiment, high-density temperature sensors placed at key locations on the test substrate, electric heating rod, and test heat pipe were used to obtain full-field measured temperature data that reflects the true temperature response.

[0095] Step S62: Extract a sparse measurement point dataset from the full-field measured temperature data, which corresponds to the actual number and location of measurement points in the solid core.

[0096] Step S63: Input the sparse measurement point dataset into the solid core temperature field reconstruction method to be verified, and obtain the reconstructed core temperature field.

[0097] Step S64: Using the measured temperature data across the entire field as a verification benchmark, compare and analyze the reconstructed core temperature field to evaluate the prediction accuracy and robustness of the solid core temperature field reconstruction method.

[0098] Optionally, the following metrics may be evaluated:

[0099] Peak temperature prediction error: the absolute deviation between the reconstructed peak value and the measured peak value;

[0100] Hotspot location accuracy: the spatial offset between the reconstructed hotspot location and the actual hotspot location;

[0101] Overall temperature distribution deviation: root mean square error of temperature across the entire field;

[0102] Anomaly identification timeliness: The time delay after an abnormal operating condition occurs when the reconstructed temperature field first reflects the anomaly.

[0103] Through the above verification process, the prediction accuracy and robustness of the temperature field reconstruction method under different working conditions can be comprehensively evaluated, providing reliable experimental support for its engineering application.

[0104] The solid core temperature field reconstruction verification system and method of this application have the following beneficial effects:

[0105] 1. Real physical experimental verification of the temperature field reconstruction method: This application no longer relies solely on numerical simulation results as the verification basis, but instead constructs a solid core temperature field reconstruction verification system with clear physical equivalence to directly obtain temperature response data from the real physical system, thereby significantly improving the engineering credibility of the temperature field reconstruction method verification results.

[0106] 2. Capable of systematically covering various operating and abnormal conditions: The experimental verification method proposed in this application is not only applicable to normal steady-state power operation conditions, but also capable of equivalently simulating typical abnormal conditions such as power changes, heat sink capacity changes, and single heat pipe failure, so that the effectiveness of the temperature field reconstruction method in accident diagnosis scenarios can also be verified.

[0107] 3. Clear equivalent relationships, explicit physical meaning, and quantitative design: This application establishes a systematic equivalent analysis framework from multiple levels, including heat source equivalence, heat conduction path equivalence, heat dissipation channel equivalence, heat sink boundary equivalence, and temperature response dynamic equivalence. Each equivalent relationship has a clear physical meaning and calculable design criteria, avoiding the uncertainty brought about by empirical or qualitative experimental methods.

[0108] 4. Adjustable test parameters and strong adaptability: In this application, key parameters such as the length and power of the electric heating rod, the total length and length of each section of the heat pipe, and the cooling conditions are all adjustable, so that the same test system can cover different reactor design parameters or different operating conditions, and has good versatility and expandability.

[0109] 5. It is beneficial to improve the engineering applicability of the temperature field reconstruction method: Through the experimental verification method of this application, the prediction error and anomaly identification capability of the temperature field reconstruction model under steady-state and transient conditions can be systematically evaluated, providing a reliable basis for the application of this type of method in actual solid reactor safety monitoring and accident diagnosis.

[0110] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0111] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

[0113] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0114] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A solid core temperature field reconstruction verification system, characterized in that, include: The simulated reactor core subsystem includes: a test substrate, multiple electric heating rods embedded in the test substrate, and multiple test heat pipes; the axial length of the test substrate is less than the axial length of the actual substrate, the test heat pipes include an evaporation section, an adiabatic section, and a condensation section, the evaporation section has the same axial length as the test substrate and is fixed in position, the length of the condensation section is adjustable; the length of the heating section of the electric heating rods is adjustable; A cooling subsystem includes at least one adjustable cooling medium circulation loop connected to the condensation section of the test heat pipe for equivalent simulation of the heat sink boundary of a solid reactor core. The cooling medium circulation loop includes a compressor, an electric valve, a mass flow meter, and a heat exchanger connected in sequence. The condensation section of the test heat pipe is inserted into the heat exchanger. The compressor and the electric valve work together to adjust the gas flow rate, thereby adjusting the heat transfer coefficient of the condensation section of the test heat pipe. The data acquisition and control subsystem is connected to the electric heating rod and the cooling subsystem respectively. It is used to adjust the heating power of the electric heating rod according to the preset working conditions, and to change the cooling capacity of the cooling subsystem by adjusting the adjustable parameters of the cooling medium circulation loop. At the same time, it collects the temperature data measured by the temperature sensors arranged at key positions of the test substrate, the electric heating rod, and the test heat pipe. The data acquisition and control subsystem is configured to: determine the axial scaling factor based on the ratio of the axial length of the test substrate to the axial length of the actual substrate; calculate the target total power of the test based on the axial scaling factor and the actual total power of the solid core; and control the sum of the heating power of all electric heating rods to be equal to the target total power of the test.

2. The system of claim 1, wherein, The data acquisition and control subsystem is also configured as follows: Determine the required volumetric power density of the electric heating rod; The heating section length of the electric heating rod is determined based on the total power of the test target, the volumetric power density, the number of electric heating rods, and the cross-sectional area of ​​the electric heating rods.

3. The system as described in claim 1, characterized in that, The data acquisition and control subsystem is configured as follows: The design heat capacity of a single test heat pipe is determined based on the total power of the test target and the number of test heat pipes. By adjusting the length of the condenser section of the test heat pipe and / or the heat transfer coefficient of the condenser section, the heat transfer capacity of the condenser section of the test heat pipe is matched with the designed heat transfer capacity.

4. The system as described in claim 1, characterized in that, The data acquisition and control subsystem is configured as follows: The temperature response curves of key measuring points during the experiment as a function of time are obtained, and the time constant of the simulated reactor core subsystem is calculated based on the temperature response curves. The time constant of the simulated core subsystem is compared with that of the solid core. Based on the comparison results, the condensation section length of the test heat pipe and / or the heat transfer coefficient of the condensation section of the test heat pipe are adjusted to iteratively adjust the time constant of the simulated core subsystem until the time constant of the simulated core subsystem matches that of the solid core.

5. The system as described in claim 4, characterized in that, The data acquisition and control subsystem is further configured to: when the time constant of the simulated core subsystem and the time constant of the solid core cannot be strictly equal, establish a time mapping relationship so that the temperature response curve of the simulated core subsystem corresponds to the temperature response curve of the solid core through time coordinate transformation.

6. The system as described in claim 1, characterized in that, Also includes: Heat pipe failure simulation device, the heat pipe failure simulation device comprising: A vent valve assembly is located at the bottom of the test heat pipe. It is used to keep the test heat pipe closed under normal operating conditions to maintain its airtightness, and to open when it is necessary to simulate failure conditions to release the sodium working fluid inside the test heat pipe. The discharge pipeline is connected to the discharge valve assembly; A throttling and metering unit is installed in the discharge pipeline to regulate and monitor the leakage rate of sodium working fluid; The sodium collection box, connected to the discharge pipeline, is used to collect leaked sodium working fluid. Its interior is a vacuum environment or filled with an inert gas environment.

7. A method for verifying the temperature field reconstruction of a solid-state reactor core using the system described in any one of claims 1 to 6, characterized in that, include: Various operating conditions and abnormal operating conditions were tested on the solid core temperature field reconstruction verification system, and the full-field measured temperature data reflecting the true temperature response were obtained through the temperature sensor. Extract a sparse measurement point dataset from the full-field measured temperature data, which corresponds to the actual number and location of measurement points in the solid core. The sparse measurement point dataset is input into the solid core temperature field reconstruction method to be verified to obtain the reconstructed core temperature field. Using the measured temperature data across the entire field as a verification benchmark, the reconstructed core temperature field is compared and error analyzed to evaluate the prediction accuracy and robustness of the solid core temperature field reconstruction method.

8. The method as described in claim 7, characterized in that, The various operating conditions and abnormal operating conditions include one or more of the following: rated power operation, power variation operation, local cooling capacity degradation operation, and single or multiple test heat pipe failure operation.

9. The method as described in claim 7, characterized in that, The simulated reactor core subsystem and the solid reactor core are physically equivalent in terms of heat source distribution, heat conduction path, heat dissipation channel, heat sink boundary, and dynamic temperature response.

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