Method and device for setting up a detector of a micro-pile, nuclear monitoring method and system

Abstract

The application discloses a micro reactor probe setting method and device, a nuclear monitoring method and system. The probe setting method comprises the following steps: obtaining the core structure parameters and the out-of-core structure parameters of a micro reactor; adjusting the initial parameters of a neutron source and the initial parameters of a starting probe according to the count rate requirement and the threshold of the proportion of fission neutrons of the starting probe under different working conditions, so as to obtain the target source intensity and the first position of the neutron source, the first sensitivity and the second position of the starting probe; adjusting the initial parameters of a power range probe through the continuity verification of the range coverage of the starting probe and the power range probe, so as to obtain the second sensitivity and the third position of the power range probe; and setting the probe of the micro reactor according to the target source intensity and the first position, the first sensitivity and the second position, and the second sensitivity and the third position. Thus, the accuracy and continuity of the probe in the nuclear monitoring of the micro reactor are improved.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to a detector setting method, device, nuclear monitoring method and system for a microreactor. Background Technology

[0002] Miniature nuclear energy devices possess high energy density and can stably and cleanly provide energy sources such as electricity and heat, while minimizing logistical supply. However, these applications place high demands on the safe operation of miniature nuclear energy devices, and nuclear monitoring is fundamental to guiding the normal operation of reactors, ensuring nuclear safety, and achieving reactivity control and protection.

[0003] Nuclear monitoring typically involves using neutron detectors to measure parameters such as neutron flux levels, power levels, and reactor cycle, providing signals for reactor operation and protection. Additionally, control rod position measurements or water level measurements may be used in pressurized water reactors to assist in core monitoring.

[0004] However, due to the compact structure and harsh internal environment (high temperature, high pressure, and high radiation) of microreactors, it is difficult to deploy traditional in-reactor detectors. Furthermore, the external structures severely interfere with neutron signals, easily leading to monitoring blind spots and signal distortion. Therefore, existing detectors designed for microreactors lack sufficient accuracy and continuity in nuclear monitoring of the reactor core. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a detector setting method, device, nuclear monitoring method and system for microreactors. The detector obtained by using the detector setting method can be arranged in a conventional reactor and can improve the accuracy and continuity of the detector's nuclear monitoring of the microreactor.

[0006] In a first aspect, embodiments of the present invention provide a detector setting method for a gas-cooled microreactor, the gas-cooled microreactor comprising multiple fuel assemblies, the method comprising:

[0007] The core structure parameters and external structure parameters of the microreactor are obtained. The core structure parameters include the initial parameters of the neutron source, and the external structure parameters include the initial parameters of the start-up detector and the power range detector.

[0008] Based on the count rate requirement and fission neutron proportion threshold of the detector under different operating conditions, the initial parameters of the neutron source and the initial parameters of the detector are adjusted to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector.

[0009] By verifying the continuity of range coverage of the start-up detector and the power range detector, the initial parameters of the power range detector are adjusted to obtain the second sensitivity and the third position of the power range detector.

[0010] The detector settings for the microreactor are configured based on the target source strength and first position of the neutron source, the first sensitivity and second position of the activation detector, and the second sensitivity and third position of the power range detector.

[0011] Optionally, adjusting the initial parameters of the neutron source and the initial parameters of the detector based on the count rate requirement and fission neutron proportion threshold under different operating conditions to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector, specifically includes:

[0012] S201. Calculate the neutron flux density corresponding to each operating condition based on the neutron source intensity and the location of the activated detector. The neutron flux density is the neutron flux density of the activated detector sensitive area under unit neutron source intensity.

[0013] S202. Based on the neutron flux density and the count rate requirement for activating the detector corresponding to each operating condition, the source strength of the neutron source and the sensitivity of the detector are adjusted to obtain the target source strength of the neutron source and the first sensitivity of the detector.

[0014] The initial parameters of the neutron source and the initial parameters of the activated detector are updated based on the target source strength and the first sensitivity.

[0015] S203. Based on the target source strength of the neutron source and the first sensitivity of the activation detector, calculate the first neutron flux density and the second neutron flux density.

[0016] Wherein, the first neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is not considered in the third operating condition, and the second neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is considered in the third operating condition. The third operating condition is when the fuel is fully loaded and the core k eff Core condition ≈0.99;

[0017] S204. If the first neutron flux density and the second neutron flux density do not meet the fission neutron proportion threshold verification condition, the position of the neutron source and the position of the activation detector are adjusted to obtain the corrected position of the neutron source and the corrected position of the activation detector, and the initial parameters of the neutron source and the initial parameters of the activation detector are updated.

[0018] Return to execute steps S201 to S204 until the first neutron flux density and the second neutron flux density meet the fission neutron proportion threshold verification condition. Then, determine the corrected position of the neutron source as the first position of the neutron source and determine the corrected position of the activated detector as the second position.

[0019] Optionally, adjusting the source strength of the neutron source and the sensitivity of the detector based on the neutron flux density and the count rate requirement for starting the detector for each operating condition to obtain the target source strength of the neutron source and the first sensitivity of the detector specifically includes:

[0020] S301. Determine whether the neutron flux density corresponding to each working condition meets the count rate requirements for starting the detector according to formula (1):

[0021]

[0022] Where Q is the source strength of the neutron source, St is the sensitivity of the neutron detector, and σ is the calculation uncertainty. Let N be the neutron flux density in the sensitive region of the detector under each neutron source strength, and let N be the count rate requirement for activating the neutron detector under each operating condition.

[0023] S302. When the neutron flux density corresponding to each working condition does not satisfy formula (1), the source strength of the neutron source and / or the sensitivity of the start detector are adjusted to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the start detector, and the initial parameters of the neutron source and the initial parameters of the start detector are updated.

[0024] S303. Based on the updated initial parameters of the neutron source and the initial parameters of the activated detector, calculate the neutron flux density corresponding to each operating condition, and return to execute S302-S303.

[0025] Until the neutron flux density corresponding to each operating condition satisfies formula (1), the corrected source strength of the neutron source is determined as the target source strength, and the corrected sensitivity of the activated detector is determined as the first sensitivity.

[0026] Optionally, the fission neutron proportion threshold verification condition includes the following formula (2):

[0027]

[0028] in, The first neutron flux density, This represents the second neutron flux density.

[0029] Optionally, the step of verifying the continuity of range coverage of the activation detector and the power range detector, and adjusting the initial parameters of the power range detector to obtain the second sensitivity and third position of the power range detector, specifically includes:

[0030] S401. Determine the measurement range of neutron flux density and power level under the full-power operation condition of the start-up detector;

[0031] S402. Based on the initial parameters of the power range detector, determine the neutron flux density and power level measurement range of the power range detector under full-power operation.

[0032] S403. Based on the measurement range of neutron flux density and power level under the full-power operation of the start-up detector and the measurement range of neutron flux density and power level under the full-power operation of the power range detector, determine whether the ranges of the start-up detector and the power range detector meet the range coverage continuity requirement.

[0033] S404. If the ranges of the start-up detector and the power range detector do not meet the range coverage continuity requirement, at least one of the following is adjusted: the sensitivity, position, power level measurement range of the power range detector, and the power level measurement range of the start-up detector. This yields corrected sensitivity, corrected position, corrected measurement range of the power range detector, and corrected measurement range of the start-up detector. The initial parameters of the power range detector and the measurement range in the initial parameters of the start-up detector are then updated.

[0034] Return to execute steps S402-S404 until the ranges of the start detector and the power range detector meet the range coverage continuity requirement. Then, determine the corrected sensitivity of the power range detector as the second sensitivity, determine the corrected position of the power range detector as the third position, determine the corrected power level measurement range of the power range detector as the target measurement range of the power range detector, and determine the corrected power level measurement range of the start detector as the target measurement range of the start detector.

[0035] Optionally, determining whether the ranges of the start-up detector and the power range detector satisfy the range coverage continuity based on the neutron flux density and power level measurement ranges of the start-up detector under full-power operation and the power range detector under full-power operation specifically includes:

[0036] The following formula (3) is used to determine whether the ranges of the start-up detector and the power range detector meet the range coverage continuity requirement:

[0037]

[0038] Wherein, ψt is the neutron flux density in the sensitive region of the detector when it is fully fueled and at full power, and ψp is the neutron flux density in the sensitive region of the power range detector when it is fully fueled and at full power. These represent the lower and upper limits of the neutron measurement range that will be activated by the detector. These are the lower and upper limits of the neutron measurement range in the power range detector, respectively.

[0039] If the neutron flux density and power level measurement ranges of the start-up detector and the power range detector are both at full power operation, and the neutron flux density and power level measurement ranges of the power range detector are at full power operation, respectively, and the ranges of the start-up detector and the power range detector are satisfied with the formula (3), then the ranges of the start-up detector and the power range detector are determined to satisfy the range coverage continuity.

[0040] If the neutron flux density and power level measurement ranges under full-power operation of the start-up detector and the power range detector do not satisfy the formula (3), it is determined that the ranges of the start-up detector and the power range detector do not satisfy the range coverage continuity.

[0041] Secondly, embodiments of the present invention also provide a nuclear monitoring method, the method comprising:

[0042] A detector is installed in the micro-pillar using the detector installation method described in the first aspect.

[0043] The detector is used to perform nuclear monitoring on the microreactor.

[0044] Thirdly, embodiments of the present invention also provide a detector setting device for a micro-pile, the device comprising:

[0045] The acquisition module is used to acquire the core structure parameters and external structure parameters of the microreactor. The core structure parameters include the initial parameters of the neutron source, and the external structure parameters include the initial parameters of the start-up detector and the power range detector.

[0046] The first adjustment module, connected to the acquisition module, is used to adjust the initial parameters of the neutron source and the initial parameters of the start-up detector according to the count rate requirement and fission neutron ratio threshold of the start-up detector under different operating conditions, so as to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the start-up detector.

[0047] The second adjustment module, connected to the first adjustment module, is used to adjust the initial parameters of the power range detector by verifying the continuity of range coverage of the start detector and the power range detector, so as to obtain the second sensitivity and the third position of the power range detector.

[0048] The setting module is connected to the first adjustment module and the second adjustment module respectively, and is used to set the detector of the microreactor according to the target source strength and first position of the neutron source, the first sensitivity and second position of the activation detector, and the second sensitivity and third position of the power range detector.

[0049] Fourthly, embodiments of the present invention also provide a nuclear monitoring system, the system comprising:

[0050] The detector setting device for the micro-repository described in the third aspect is used to set a detector in the micro-repository;

[0051] The detection module is used to perform nuclear monitoring on the microreactor using the detector.

[0052] The detector setup method for microreactors of this invention can adjust the source strength of the neutron source, the sensitivity of the detector, and its placement position according to the count rate requirement and the fission neutron ratio threshold. This ensures that the detector can effectively monitor the nuclear state of the reactor even in harsh environments such as high temperature, high pressure, and high radiation. By verifying the continuity of range coverage between the detector and the power range detector, the sensitivity and placement position of the power range detector are further adjusted to avoid monitoring blind spots or signal distortion caused by interference from complex external structures, as is common with traditional detectors. Therefore, the adaptability and accuracy of the detector under harsh conditions are improved, achieving high-precision and continuous monitoring of the microreactor nuclear reactor. Attached Figure Description

[0053] Figure 1 This is a flowchart of a detector setting method for a micro-pile according to Embodiment 1 of the present invention;

[0054] Figure 2 This is a flowchart of a method for setting up a detector for another micro-pile according to Embodiment 1 of the present invention;

[0055] Figure 3 : This is a radial diagram showing the layout of the gas-cooled microreactor core and nuclear monitoring system according to Embodiment 1 of the present invention;

[0056] Figure 4 : This is an axial view of the gas-cooled microreactor core and nuclear monitoring system layout of Embodiment 1 of the present invention;

[0057] Figure 5 : A schematic diagram of the neutron detector structure in Embodiment 1 of the present invention;

[0058] Figure 6 : This is a range coverage diagram of the detector power measurement range in Embodiment 1 of the present invention;

[0059] Figure 7 : This is a structural diagram of a detector setting device for a micro-pile according to Embodiment 3 of the present invention.

[0060] The markings in the diagram mean:

[0061] 1. Carriage frame; 2. Shielding and insulation layer; 3. Pressure vessel; 4. Boron-containing carbon bricks;

[0062] 5. Reflector layer; 6. Fuel assembly; 7. Neutron source; 8. Second set of control rods; 9. First set of control rods. Detailed Implementation

[0063] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0065] Compared to the difficulty of accessing large power grids and the massive logistical demands of diesel generators, micro nuclear energy devices offer high energy density and can stably and cleanly provide electricity, heat, and other energy sources while minimizing logistical requirements. However, these applications place high demands on the safe operation of micro nuclear energy devices, and nuclear monitoring is fundamental to guiding normal reactor operation, ensuring nuclear safety, and achieving reactivity control and protection.

[0066] Nuclear monitoring typically uses neutron detectors to measure parameters such as neutron flux levels, power levels, and reactor cycle, providing signals for reactor operation and protection. It may also include control rod position measurements or water level measurements within pressurized water reactors to assist core monitoring. In commercial reactors, in addition to external source range detectors, intermediate range detectors, and power range detectors, second-generation and "second-generation+" pressurized water reactors generally use mobile fission chamber in-reactor detectors. Neutron measurements are independent of other measurement systems, and the whole-reactor flux map is measured time-divisionally, which is time-consuming and involves high radiation doses.

[0067] However, microreactors are characterized by their compact internal layout, small and complex active zones, high core operating temperatures, and harsh operating environments for in-reactor instruments. They face challenges such as high temperature, high pressure, high radiation, and limited space, making it difficult to find suitable in-reactor detector types. Furthermore, inspection and maintenance are also challenging. While pebble bed high-temperature gas-cooled reactors address the limitation of placing detectors within fuel assemblies by using detectors within side reflectors, microreactor systems are compact, making it difficult to create numerous operating channels in the pressure vessel. Moreover, the thin reflector layer and the high temperature of the reflector layer in microreactors easily exceed the detector's operating temperature limits. Currently, there are no operational mobile microreactors, nor are there mature microreactor nuclear monitoring methods and systems that can be directly applied.

[0068] Example 1:

[0069] Based on the above research, in order to solve the aforementioned technical problems, such as Figure 1 As shown, this embodiment provides a detector setting method for a microreactor, which can be applied to nuclear power plants.

[0070] Specifically, it includes the following steps 101 to 104.

[0071] Step 101: Obtain the core structure parameters and external structure parameters of the microreactor. The core structure parameters include the initial parameters of the neutron source.

[0072] Among them, the external structural parameters include the initial parameters of the start-up detector and the power range detector.

[0073] Core structural parameters: These include the initial parameters of the neutron source, i.e., the initial state of the neutron source within the reactor core of the microreactor (e.g., source strength, energy spectrum, etc.). External structural parameters: These involve the initial parameters of the start-up detectors and power range detectors. The external structure typically affects the detector's signal reception, especially the propagation and capture of neutron signals.

[0074] Specifically, core structural parameters (such as fuel assembly size, reflector thickness, control rod position, initial position and source strength of neutron source) and external structural parameters (such as shield thickness, pressure vessel size, initial position and sensitivity of start-up detector and power range detector) of microreactors can be obtained through design drawings, Monte Carlo simulations or experimental measurements.

[0075] Three-dimensional modeling tools (such as CAD) can be used to construct the core geometry model, and material databases (such as ENDF / B) can be used to define neutron transport characteristics, providing basic data for subsequent simulations.

[0076] Step 102: Adjust the initial parameters of the neutron source and the initial parameters of the detector based on the count rate requirements and fission neutron ratio threshold under different operating conditions to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector.

[0077] The fission neutron percentage threshold is a key parameter for determining whether a detector can effectively detect core reactions, reflecting the effectiveness of the detector's response to fission neutrons.

[0078] Specifically, the initial parameters of the neutron source and the detector are adjusted according to the count rate requirements for starting the detector under different operating conditions and the fission neutron proportion threshold. By adjusting the initial parameters of the neutron source, i.e., selecting a suitable neutron source (where the source intensity and energy spectrum distribution meet the target source strength) and determining the setting position of the neutron source (i.e., the first position), it is ensured that the detector can obtain sufficient signal strength under different operating conditions. By adjusting the sensitivity of the detector (i.e., selecting a detector with appropriate sensitivity) and the setting position (i.e., the second position), it is ensured that the detector can effectively respond to the neutron signal of the microreactor.

[0079] Step 103: By verifying the continuity of range coverage of the start detector and the power range detector, the initial parameters of the power range detector are adjusted to obtain the second sensitivity and the third position of the power range detector.

[0080] Specifically, the continuity of range coverage of the start-up detector and the power range detector is verified, and the initial parameters of the power range detector are adjusted to determine a more suitable sensitivity and position of the power range detector. This ensures that the range and detection capability of the start-up detector and the power range detector can be seamlessly connected under different power output and detection conditions, avoiding monitoring blind spots.

[0081] Step 104: Configure the detectors for the microreactor based on the target source strength and first position of the neutron source, the first and second sensitivities and second positions of the activation detector, and the second and third sensitivities and third positions of the power range detector.

[0082] Specifically, the adjusted parameters (neutron source target strength and location, start-up detector sensitivity and location, power range detector sensitivity and location) are applied to the microreactor, detectors are installed and a signal processing system is configured to achieve continuous monitoring of the microreactor under all operating conditions from loading to full power.

[0083] In this embodiment, by adjusting the initial parameters of the neutron source and detector, accurate nuclear monitoring data is ensured even under complex and harsh in-reactor environments. Through continuity verification and sensitivity adjustment, seamless coverage of the detector's measurement range is ensured, and the detector can operate effectively under external structural interference, avoiding the blind zone problem common in traditional detectors. Parameter adjustments based on different operating conditions ensure real-time and accurate monitoring of the microreactor's response, improving the continuity and accuracy of nuclear monitoring. Even under different operating states or environmental conditions, the detector reliably responds to neutron signals, providing stable data support.

[0084] Optionally, S102 above specifically includes the following steps:

[0085] S201. Based on the source strength of the neutron source and the location of the detector activation, calculate the neutron flux density corresponding to each operating condition. The neutron flux density is the neutron flux density in the sensitive area of ​​the detector activation under a unit neutron source strength.

[0086] S202. Based on the neutron flux density and the count rate requirement for activating the detector corresponding to each operating condition, adjust the source strength of the neutron source and the sensitivity of the detector to obtain the target source strength of the neutron source and the initial sensitivity of the detector.

[0087] The initial parameters of the neutron source and the initial parameters of the detector are updated based on the target source strength and the first sensitivity.

[0088] S203. Based on the target source strength of the neutron source and the initial sensitivity of the detector, calculate the first neutron flux density and the second neutron flux density.

[0089] The first neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is not considered in the third operating condition; the second neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is considered in the third operating condition; and the third operating condition is the core state with full fuel loading and core keff≈0.99.

[0090] S204. If the first and second neutron flux densities do not meet the fission neutron proportion threshold verification condition, the positions of the neutron source and the detector activation are adjusted to obtain the corrected positions of the neutron source and the detector activation, and the initial parameters of the neutron source and the detector activation are updated.

[0091] Return to execute S201 to S204 until the first neutron flux density and the second neutron flux density meet the fission neutron proportion threshold verification condition. Then, determine the corrected position of the neutron source as the first position of the neutron source and determine the corrected position of the detector as the second position.

[0092] The operating conditions of the micro-relay can be divided into the following four types:

[0093] First operating condition: No fuel core, count rate requirement is N1.

[0094] Second operating condition: Complete reactor shutdown, fuel loading but 0 < k eff <0.99, neutron count rate requirement is N2;

[0095] Third working condition: k eff ≈0.99, load fuel and set subcritical state, neutron count rate required is N3.

[0096] Fourth operating condition: Full power operation.

[0097] Specifically, firstly, S201 uses Monte Carlo simulation to obtain the neutron flux density of the neutron source under each operating condition based on the source strength of the neutron source and the location of the activated detector;

[0098] For S202, the source strength of the neutron source (i.e., the target source strength) and the sensitivity of the detector are adjusted according to the neutron flux density and the count rate requirement for starting the detector under each operating condition. The target source strength is a key parameter to ensure that the detector can accurately monitor the required neutron signal under this operating condition, while the sensitivity adjustment of the detector is to enable the detector to effectively respond to the neutron signal under actual operating conditions. When the neutron source is fixed, only the detector sensitivity needs to be adjusted, and a detector with suitable sensitivity can be selected.

[0099] For S203, the performance of the detector under different operating conditions was evaluated, especially the difference in neutron flux when considering fuel fission and when not considering fission. The different effects of fission neutrons and non-fission neutrons on the detector response were analyzed, so as to provide data support for the next step of determining whether the fission neutron proportion threshold is met.

[0100] For S204, if the first and second neutron flux densities fail to meet the fission neutron proportion threshold verification condition, the positions of the neutron source and the activation detector need to be adjusted. Modifying the detector's position optimizes the neutron signal capture efficiency and reduces interference from external structures, thereby improving signal accuracy. After adjustment, calculations and verifications for S201 to S203 are performed again. This process is repeated until the fission neutron proportion threshold is met. Finally, the corrected position of the neutron source is determined as the first position, the corrected position of the activation detector is determined as the second position, and the relevant parameters are updated.

[0101] In this embodiment, by precisely adjusting the source strength of the neutron source and the sensitivity of the detector, the count rate requirements for detector activation are met under each operating condition, ensuring effective monitoring of the neutron signal of the microreactor under different conditions. Through position adjustments and parameter updates, the interference of external structures on the neutron signal is resolved, allowing the neutron source and detector layout to better adapt to the specific environment of the microreactor, avoiding blind spots and signal weakening, and improving the stability and adaptability of the detector under harsh conditions. This improves the monitoring accuracy and continuity of the microreactor nuclear reactor, providing a more reliable technical guarantee for the safe operation of the microreactor.

[0102] Optionally, S202 above specifically includes the following steps:

[0103] S301. Determine whether the neutron flux density corresponding to each working condition meets the count rate requirements for starting the detector according to formula (1):

[0104]

[0105] Where Q is the source strength of the neutron source, St is the sensitivity of the neutron detector, and σ is the calculation uncertainty. Let N be the neutron flux density in the sensitive region of the detector under each neutron source strength, and let N be the count rate requirement for activating the neutron detector under each operating condition.

[0106] S302. When the neutron flux density corresponding to each working condition does not satisfy formula (1), the source strength of the neutron source and / or the sensitivity of the start detector are adjusted to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the start detector, and the initial parameters of the neutron source and the start detector are updated.

[0107] S303. Based on the updated initial parameters of the neutron source and the initial parameters for starting the detector, calculate the neutron flux density corresponding to each operating condition, and return to execute S302~S303.

[0108] Until the neutron flux density corresponding to each working condition satisfies formula (1), the corrected source strength of the neutron source is determined as the target source strength, and the corrected sensitivity of the activated detector is determined as the first sensitivity.

[0109] Specifically, for S301, according to formula (1), it is determined whether the neutron flux density corresponding to each working condition meets the count rate requirement of the corresponding start detector.

[0110] For S302, if the neutron flux density under a certain operating condition does not meet the requirements of formula (1), the source strength of the neutron source and / or the sensitivity of the detector are adjusted to meet the requirements. In S301, if it is determined that the neutron flux density under a certain operating condition does not meet the requirements, the source strength Q of the neutron source or the sensitivity St of the detector needs to be adjusted. Depending on the actual situation, the source strength, sensitivity, or both can be adjusted. The adjusted neutron source corrects the source strength and / or corrects the sensitivity to update the initial parameters, ensuring that the new settings can meet the count rate requirements and maintain the accuracy of the detector.

[0111] For S303, the neutron flux density under each operating condition is recalculated based on the adjusted neutron source strength and detector sensitivity to ensure that the count rate requirement is met. The neutron flux density under each operating condition is recalculated based on the adjusted neutron source strength and detector sensitivity to check if it meets the requirements in formula (1). If the flux density still does not meet the requirements after adjustment, S302 is adjusted again until the neutron flux density under each operating condition meets the count rate requirement, reaching the final corrected source strength and sensitivity values.

[0112] In this embodiment, iterative adjustments are made according to formula (1) to ensure that the neutron flux density under each operating condition meets the count rate requirement of the start-up detector. This allows for dynamic adjustment of the neutron source strength and the sensitivity of the start-up detector, ensuring accurate response under various operating conditions. It maximizes the sensitivity and response capability of the start-up detector under different operating conditions, avoiding detection errors caused by environmental changes or unsuitable parameters, thus optimizing the parameters of the neutron source and detector, and making neutron monitoring in actual operation of nuclear reactors such as microreactors more accurate.

[0113] Optionally, the above-mentioned fission neutron proportion threshold verification conditions include the following formula (2):

[0114]

[0115] in, The first neutron flux density is the density when the fuel is fully loaded and the core k eff Under the operating condition of ≈0.99 (condition 3), the fuel fission reaction can be shut down using Monte Carlo simulation, and only the contributions of the neutron source and non-fission neutrons (such as scattering and absorption) can be calculated.

[0116] Given the second neutron flux density, under the same operating condition (third operating condition), with the fuel fission reaction initiated, calculate the total neutron flux density (including the combined contributions of neutron sources, fission neutrons, and non-fission neutrons).

[0117] Specifically, formula (2) ensures that the detector monitors the core fission activity rather than background noise (such as source neutrons or scattered neutrons) by quantifying the proportion of fission neutrons in the total neutron signal. By verifying the proportion of fission neutrons (>95%), the interference of external structures on the neutron signal is effectively eliminated, and the signal-to-noise ratio of the monitoring data is improved.

[0118] Because the neutron flux of a microreactor varies greatly from fuel loading to full-power operation, a single detector cannot cover the entire range. Therefore, a complementary design of a starter detector (high sensitivity, low range) and a power range detector (wide range, high upper limit) can ensure blind-spot-free monitoring under all operating conditions.

[0119] Optionally, S103 above may specifically include the following steps:

[0120] S401. Determine the measurement range of neutron flux density and power level under the full-power operation condition of the detector.

[0121] S402. Based on the initial parameters of the power range detector, determine the neutron flux density and power level measurement range of the power range detector under full-power operation.

[0122] S403. Based on the measurement range of neutron flux density and power level under full-power operation of the start-up detector and the measurement range of neutron flux density and power level under full-power operation of the power range detector, determine whether the range of the start-up detector and the power range detector meets the range coverage continuity requirement.

[0123] S404. If the ranges of the start-up detector and the power range detector do not meet the range coverage continuity requirement, at least one of the following should be adjusted: the sensitivity, position, and power level measurement range of the power range detector, and the power level measurement range of the start-up detector. This will yield corrected sensitivity, corrected position, corrected measurement range of the power range detector, and corrected measurement range of the start-up detector. The initial parameters of the power range detector and the initial parameters of the start-up detector should also be updated.

[0124] Return to execute steps S402 to S404 until the ranges of the start detector and the power range detector meet the range coverage continuity requirement. Then, determine the corrected sensitivity of the power range detector as the second sensitivity, determine the corrected position of the power range detector as the third position, determine the corrected measurement range of the power range detector as the target measurement range of the power range detector, and determine the corrected measurement range of the start detector as the target measurement range of the start detector.

[0125] In this embodiment, it is first necessary to determine the neutron flux density and power level measurement range under the full-power operation condition (fourth condition) of the start-up detector. Then, based on the initial parameters of the power range detector, its corresponding parameters under the full-power operation condition are determined. Next, the ranges of the two detectors are compared to determine whether the coverage continuity requirement is met. If not, the sensitivity or position of the power range detector is adjusted, and the verification is repeated until the condition is met.

[0126] Specifically, for S401, a core model under full-power operation can be constructed using Monte Carlo simulations (such as MCNP or Serpent), loading actual fuel assemblies and setting thermal parameters (such as coolant temperature and pressure) to simulate the neutron transport process and output the neutron flux density in the detector's sensitive region. Based on the sensitivity and range of the start-up detector, determine the power range that the start-up detector can measure.

[0127] For S402, based on the initial parameters of the power range detector, the neutron flux density of the power range detector under full-power operation is calculated using Monte Carlo simulation. And determine the measurement range based on its technical specifications.

[0128] For S403, the neutron flux density and measurement range of the start-up detector and the power range detector under full-power conditions are used to verify whether their range coverage overlaps or is continuous. In other words, it is necessary to determine whether the start-up detector and the power range detector have overlapping ranges across the entire power range.

[0129] For S404, if the range coverage is discontinuous or insufficiently overlapping (i.e., range coverage continuity is not met), it is necessary to adjust at least one of the following: the sensitivity and position of the power range detector, and the power level measurement range of both the power range detector and the start-up detector, to ensure continuous coverage between the power range detector and the start-up detector. Adjusting the parameters of the power range detector can involve adjusting its sensitivity (e.g., replacing it with a detector of different sensitivities, thereby changing its response to neutron flux), adjusting its position (changing the spatial relationship between the detector and the area to be measured), or adjusting the upper and lower limits of the neutron measurement range. The measurement range parameters of the start-up detector can also be adjusted. After adjustment, the initial parameters of either the power range detector or the start-up detector need to be updated, and the loop from S402 to S404 needs to be returned until the range meets the coverage continuity requirement. The corrected sensitivity and corrected position of the power range detector are then determined as the second sensitivity and third position of the power range detector, and the corrected range of either the start-up detector or the power range detector is determined as the target measurement range for both detectors.

[0130] In this embodiment, a continuity verification mechanism is used to optimize the parameter configuration of the power range detector, enabling both the start-up detector and the power range detector to cover the entire measurement range. This ensures that the range coverage of the start-up detector and the power range detector remains continuous. The measurement range of the detectors is optimized to ensure that the system responds accurately within each power range.

[0131] Optionally, the determination of whether the ranges of the start-up detector and the power range detector satisfy the range coverage continuity based on the measurement ranges of neutron flux density and power level under full-power operation of the start-up detector and the power range detector under full-power operation specifically includes:

[0132] The following formula (3) is used to determine whether the ranges of the start-up detector and the power range detector meet the range coverage continuity requirement:

[0133]

[0134] Wherein, ψt is the neutron flux density in the sensitive region of the detector when it is fully fueled and at full power, and ψp is the neutron flux density in the sensitive region of the power range detector when it is fully fueled and at full power. These represent the lower and upper limits of the neutron measurement range that will be activated by the detector. These are the lower and upper limits of the neutron measurement range in the power range detector, respectively.

[0135] Under the condition that the neutron flux density and power level measurement range of the start-up detector and the neutron flux density and power level measurement range of the power range detector are satisfied with formula (3), the range of the start-up detector and the power range detector are determined to satisfy the range coverage continuity.

[0136] If the measurement ranges of neutron flux density and power level under full operating conditions of the start-up detector and the power range detector do not satisfy formula (3), it is determined that the ranges of the start-up detector and the power range detector do not satisfy the range coverage continuity.

[0137] The detector's measurement range is determined based on its technical specifications. Measurement range coverage continuity refers to the seamless connection between the measurement ranges of two detectors under different power conditions, without overlap or gaps, ensuring the system functions normally throughout the entire measurement range.

[0138] Specifically, the range continuity of the start detector and the power range detector is quantitatively judged by formula (3) to ensure that the two can achieve seamless connection and continuous coverage under high power conditions, thus avoiding blank areas or overlapping areas between different power ranges.

[0139] Example 2: This example provides a nuclear monitoring method applied to a microreactor, specifically including:

[0140] The detector setting method for the micro-stack provided in any of the above embodiments is used to set a detector in the micro-stack;

[0141] Nuclear monitoring of the microreactor is performed using a detector.

[0142] Specifically, by combining the aforementioned detector setup method for microreactors, detectors for microreactors are designed, and then nuclear monitoring of the microreactors is performed using these detectors. This solves the range coverage problem in microreactor monitoring, ensuring that the detectors can achieve accurate monitoring under various power conditions within the reactor, thereby improving the safety, stability, and operating efficiency of the microreactor.

[0143] To facilitate understanding of the detector setting method for the micro-stack provided in this embodiment, a practical application description of the above method is provided here.

[0144] Taking a typical gas-cooled microreactor core as an example, a typical gas-cooled microreactor core model is as follows: Figure 3 and Figure 4As shown, the reactor core consists of hexagonal prism fuel assemblies 6 with identical geometry within the active zone, control rod assemblies (first set of control rods 9 and second set of control rods 8), and a reflector layer 5. Outside the core, there are boron-carbon bricks 4, a pressure vessel 3, a shielding and insulation layer 2, a carriage frame 1, a neutron source 7, etc. The core has 12 radial rows of fuel assemblies, and each row has 3 axial layers of fuel assemblies, resulting in a total of 36 fuel assemblies. Two sets of control rods are arranged. The first set of control rods 9 is located outside the active zone and has 6 sets of control rods, used for core operation control, cold shutdown, hot shutdown, and emergency shutdown. The second set of control rods 8 is located at the core center and has 1 set of control rods, serving as a backup shutdown method. Hot shutdown of the core is only implemented when the first set of control rods fails.

[0145] Since the primary source of the detector's nuclear signal is thermal neutrons, which are highly susceptible to scattering and absorption by the boron-containing carbon bricks 4, pressure vessel 3, and shielding insulation layer 2 outside the reactor core, the thermal neutron signal measured by the detector cannot accurately reflect the core state. To avoid interference from the complex external structure on the detector's neutron monitoring, such as... Figure 5 As shown, a cadmium layer is arranged around the sensitive area of ​​the detector to absorb thermal neutrons, and a polyethylene layer is arranged to slow down fast neutrons. Ultimately, fast neutrons are monitored to prevent the external structure from having an excessive impact on the neutron count of the detector.

[0146] Analysis of nuclear monitoring methods for typical gas-cooled microreactor cores, including specific implementation steps, such as... Figure 2 As shown:

[0147] S21. Obtain the microreactor core loading and external structure.

[0148] In the initial design phase, a core model of the microreactor and its associated detector models are first established. This process includes the arrangement of fuel assemblies within the core, the configuration of external structures (such as shielding layers and pressure vessels), and the design of detector activation locations. This provides the foundational model for subsequent calculations and parameter determination.

[0149] Specifically, (1) obtain the core loading scheme of the micro reactor and the dimensions and materials of the external structure:

[0150] Core geometry parameters include fuel assembly dimensions, reflector thickness, and control rod positions.

[0151] Material composition: fuel type (such as hexagonal prism fuel assembly), moderator (graphite), coolant (gas), shielding layer (boron-carbon brick), etc.

[0152] External structural parameters: pressure vessel dimensions, shielding and insulation layer thickness, etc.

[0153] S22. Establish a three-dimensional core and external structure model without fuel loading.

[0154] Model building: A three-dimensional reactor core model was built using the Monte Carlo program, with the fuel assembly locations replaced by graphite blocks.

[0155] Embedded neutron source: Defines the initial location of the neutron source (such as the core center or within the reflector).

[0156] Embedded start-up detector: Initially set the location of the start-up detector (e.g., outside the outer shielding layer of the stack).

[0157] Output parameters: Generate the neutron flux distribution in the fuel-free state.

[0158] S23. Establish a three-dimensional model of the reactor core and external structure with the fuel fully loaded.

[0159] Replace fuel components: Load actual fuel components into the model.

[0160] Embedded power range detector: Initially determine the location of the power range detector (e.g., multi-layer axial arrangement outside the stack).

[0161] Output parameters: Neutron flux distribution and k under full fuel conditions. eff value.

[0162] S24: Determine the neutron source strength and activate the detector sensitivity.

[0163] S241, Define operating conditions.

[0164] Operating condition 1: Core state without fuel loading, neutron count rate requirement N1;

[0165] Operating Condition 2: Core state with full fuel loading and complete shutdown, neutron count rate requirement N2;

[0166] Condition 3: Fully loaded with fuel and core k eff For a core state of approximately 0.99, a neutron count rate of N3 is required.

[0167] Operating Condition 4: Full power operation.

[0168] S242. Calculate the neutron flux density in the sensitive region of the detector under unit neutron source intensity.

[0169] Monte Carlo simulation can be used to obtain the corresponding values ​​for each working condition. The value of .

[0170] S243. Determine whether the neutron source intensity and the activation detector sensitivity satisfy the following formula (1) under operating conditions one to three.

[0171] The neutron source strength and the activation detector sensitivity are determined by the following formula (1):

[0172]

[0173] In the formula,

[0174] Q represents the source strength of the neutron source. In this embodiment, an americium-beryllium neutron source with a source strength of 5.0E+06n / s can be selected.

[0175] St represents the sensitivity of the neutron detector.

[0176] σ is the calculation uncertainty, conservatively taken as 20%;

[0177] The neutron flux density in the sensitive region of the neutron detector is set for each unit neutron source strength under various operating conditions.

[0178] N represents the required count rate for starting the neutron detector under various operating conditions.

[0179] If the neutron source intensity and the activation detector sensitivity both satisfy formula (1) under operating conditions one to three, then proceed to S25;

[0180] If the neutron source strength and the activation detector sensitivity do not satisfy formula (1) under any of the operating conditions 1 to 3, then adjust the neutron source strength or the activation detector sensitivity, and return to execute S242 to S243.

[0181] Table 1 shows examples of detector sensitivity requirements under different operating conditions. Therefore, when selecting an americium-beryllium neutron source with a source strength of 5.0E+06n / s, a pulsed neutron detector with a sensitivity of 100 cps / flux can be selected for activation.

[0182] Table 1. Sensitivity requirements for detector startup under different operating conditions.

[0183]

[0184] S25. Determine the location of the neutron source and activate the detector.

[0185] S251. Neutron flux density in the detector's sensitive region under both calculation conditions considering and ignoring fission. and

[0186] S252, Judgment and Does it satisfy formula (2)?

[0187] The positions of the neutron source and the start-up neutron detector are determined by the following formula (2), that is, the positions of the neutron source and the start-up neutron detector must satisfy formula (2):

[0188]

[0189] In the formula, For fuel assemblies fully loaded, and core k eff ≈0.99, and without considering fuel fission neutron reactions, the neutron flux density in the detector's sensitive region is activated;

[0190] For fuel assemblies fully loaded, and core k eff ≈0.99, and considering various neutron reactions such as fuel fission, the neutron flux density in the detector's sensitive region is activated;

[0191] like and If formula (2) is satisfied, then proceed to S26;

[0192] like and If formula (2) is not satisfied, then adjust the position of the neutron source and the start detector, and return to execute S242~S252.

[0193] In one example, the location of the neutron source and the activation detector are as follows: Figure 3 and Figure 4 As shown, the neutron source is located within the reactor core, radially on the graphite block assembly at the center of the core, and axially extending 15 cm into the active region from the coolant inlet side. The activation detector is radially positioned outside the outer shielding insulation layer and inside the chassis frame, axially aligned with the third fuel assembly. Calculation results show that fission neutrons account for 97.6% of the measured neutrons, meeting the design requirements.

[0194] S26. Determine the detector's measurement range.

[0195] S261. Obtain the position, structure, and sensitivity of the power range detector, as well as the upper and lower limits of the neutron measurement range of the start detector and the power range detector.

[0196] S262. Calculate the neutron flux densities ψt and ψp in the sensitive region of the detector and the power range detector under operating condition four.

[0197] S263, Calculation of the power level measurement range of the detector and power range detector under four operating conditions. and

[0198] S264. Determine whether the power level measurement range of the start detector and the power range detector meets the formula (3).

[0199]

[0200] In the formula,

[0201] ψt is the neutron flux density in the sensitive region of the detector when it is fully fueled and operating at full power, which is 3.73E+08n·cm. -2 ·s -1 ;

[0202] ψp is the neutron flux density in the sensitive region of the power range detector when fully fueled and operating at full power, which is 2.34E+08n·cm. -2 ·s -1 ;

[0203] These represent the lower and upper limits of the neutron measurement range for activating the detector, respectively, and are 1.25E-02n·cm. -2 ·s -1 and 2.0E+05n·cm -2 ·s -1 ;

[0204] These represent the lower and upper limits of the neutron measurement range for the power range detector, respectively, which are 5.0E+02n·cm. -2 ·s -1 and 1.4E+10n·cm -2 ·s -1 .

[0205] If the power level measurement range of the start detector and the power range detector satisfies formula (3), then the outputs are the neutron source intensity, the start detector sensitivity, the neutron source and start detector positions, and the power range detector position and sensitivity.

[0206] If the power level measurement range of the start detector and the power range detector does not meet the formula (3), then adjust the position or sensitivity of the power range detector, as well as the upper and lower limits of the neutron measurement range of the start detector and the power range detector, and return to execute S261~S263.

[0207] In one example, such as Figure 6 As shown, Figure 6 This is a power measurement range coverage diagram for the start-up detector and the power range detector. It can be seen that the start-up detector can measure a minimum of 3.3E-11* full power, far below the Doppler heating point power level. The power range detector can measure a maximum of 60* full power. There is a range coverage of more than two orders of magnitude between the two types of detectors, enabling monitoring from 3.3E-11* full power to 60* full power levels, ensuring that the reactor core is always within the monitored range.

[0208] In another example, this application provides a gas-cooled microreactor nuclear testing system, which includes the aforementioned americium-beryllium neutron source, start-up detector, power range detector, and supporting auxiliary circuitry, signal processor, and computer memory.

[0209] Neutron sources, provided that environmental conditions such as temperature are met, can be located within the active region of the reactor core, within the reflector layer, or outside the reactor.

[0210] The start-up detectors are source-range pulsed neutron detectors, and multiple sets are arranged. Subject to environmental constraints such as temperature, they can be located either inside or outside the microreactor core.

[0211] For example, the start-up detector is equipped with two sets of pulsed neutron detectors, each with one neutron proportional counter tube. The start-up detector is radially located outside the external shielding insulation layer and inside the vehicle frame, and axially aligned with the third fuel assembly.

[0212] The power range detectors are wide-range current-type neutron detectors, arranged in multiple groups, with each group containing multiple detectors at different heights along the axis. Subject to environmental constraints such as temperature, the power range detectors can be located either inside or outside the microreactor core.

[0213] For example, the power range detector is equipped with three sets of current-type neutron detectors, and each set has four gamma-compensated ionization chambers arranged at different axial heights. The power range detector is radially located outside the reactor core's external shielding insulation layer and inside the vehicle frame, and axially approximately flush with the reactor core's active region.

[0214] The detector's sensitive area is surrounded by an absorber layer and a strong moderator layer. The absorber layer is made of materials including, but not limited to, cadmium, boron, and gadolinium, while the strong moderator layer is made of materials including, but not limited to, polyethylene.

[0215] The power range detector has an absorber layer and a strong moderator layer arranged around its sensitive area. The absorber layer material includes, but is not limited to, cadmium, boron, and gadolinium, and the strong moderator layer material includes, but is not limited to, polyethylene.

[0216] This gas-cooled microreactor nuclear monitoring system ensures that the gas-cooled microreactor core remains within the neutron monitoring range from fuel loading and startup to operation, avoiding monitoring blind spots and unknown core states. It also avoids similar problems as the overlapping ranges of too many detectors in pressurized water reactors. This system solves the problem of the lack of mature core monitoring systems for microreactors, provides nuclear measurement signal support for the operation control and nuclear safety of microreactors, and is of great significance to the research and development of microreactors.

[0217] This application's embodiments achieve full-process neutron monitoring of the microreactor during fuel loading, startup, and operation by employing a pulsed source range detector as the startup detector and a wide-range current-type detector as the power range detector. This method, coupled with the neutron source, startup detector, and power range detector, avoids monitoring blind spots and unknown core states, and also avoids the problem of overlapping detector ranges found in pressurized water reactors. By setting an absorber layer and a strong moderator layer around the detector, monitoring of fast neutrons in the core is achieved, avoiding excessive interference from complex external structures. This invention solves the problem of difficulty in core nuclear characteristic monitoring in microreactors due to their compact layout, unsuitability for a large number of in-core detectors, and lack of mature nuclear monitoring systems. Without compromising the compact layout of the microreactor, it provides nuclear measurement signal support for the operation control and nuclear safety of the microreactor, which is of great significance for the realization of core monitoring, intelligent operation, remote monitoring, and safe shutdown functions of microreactor products, and provides engineering support for microreactor product development.

[0218] Example 3:

[0219] like Figure 7 As shown, this embodiment provides a detector setting device 700 for a micro-pile, the device comprising:

[0220] The acquisition module 701 is used to acquire the core structure parameters and external structure parameters of the microreactor. The core structure parameters include the initial parameters of the neutron source, and the external structure parameters include the initial parameters of the start-up detector and the power range detector.

[0221] The first adjustment module 702, connected to the acquisition module 701, is used to adjust the initial parameters of the neutron source and the initial parameters of the detector according to the count rate requirement and fission neutron ratio threshold under different operating conditions, so as to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector.

[0222] The second adjustment module 703, connected to the first adjustment module 702, is used to adjust the initial parameters of the power range detector by verifying the continuity of range coverage of the start detector and the power range detector, so as to obtain the second sensitivity and the third position of the power range detector.

[0223] The setting module 704 is connected to the first adjustment module 702 and the second adjustment module 703 respectively, and is used to set the detector of the microreactor according to the target source strength and first position of the neutron source, the first sensitivity and second position of the start detector, and the second sensitivity and third position of the power range detector.

[0224] Optionally, the first adjustment module 702 includes:

[0225] The first calculation unit is used to execute S201: calculate the neutron flux density corresponding to each working condition based on the source strength of the neutron source and the location of the detector activation. The neutron flux density is the neutron flux density of the sensitive area of ​​the detector activation under a unit neutron source strength.

[0226] The first adjustment unit, connected to the first calculation unit, is used to execute S202: Adjusting the source strength of the neutron source and the sensitivity of the detector activation based on the neutron flux density and the count rate requirement for each operating condition, to obtain the target source strength of the neutron source and the first sensitivity of the detector activation.

[0227] The initial parameters of the neutron source and the initial parameters of the detector are updated based on the target source strength and the first sensitivity.

[0228] The second calculation unit, connected to the first adjustment unit, is used to execute S203: calculate the first neutron flux density and the second neutron flux density based on the target source strength of the neutron source and the initial sensitivity of the detector.

[0229] Wherein, the first neutron flux density is the neutron flux density in the detector sensitive area when the third operating condition is not considered (without considering fuel fission), the second neutron flux density is the neutron flux density in the detector sensitive area when the third operating condition is considered (considering fuel fission), and the third operating condition is when the fuel is fully loaded and the core k eff Core condition ≈0.99;

[0230] The second adjustment unit, connected to the second calculation unit, is used to execute S204: If the first neutron flux density and the second neutron flux density do not meet the fission neutron proportion threshold verification condition, the position of the neutron source and the position of the detector are adjusted to obtain the corrected position of the neutron source and the corrected position of the detector, and the initial parameters of the neutron source and the detector are updated.

[0231] Control the first calculation unit, the first adjustment unit, and the second calculation unit to execute S201 to S204 until the first neutron flux density and the second neutron flux density meet the fission neutron ratio threshold verification condition. Then, determine the corrected position of the neutron source as the first position of the neutron source and determine the corrected position of the detector as the second position.

[0232] Optionally, the first adjustment unit mentioned above includes:

[0233] The first judgment subunit is used to execute S301: according to formula (1), determine whether the neutron flux density corresponding to each working condition meets the count rate requirements for starting the detector.

[0234]

[0235] Where Q is the source strength of the neutron source, St is the sensitivity of the neutron detector, and σ is the calculation uncertainty. Let N be the neutron flux density in the sensitive region of the detector under each neutron source strength, and let N be the count rate requirement for activating the neutron detector under each operating condition.

[0236] The first adjustment subunit is used to perform S302: when the neutron flux density corresponding to each working condition does not satisfy formula (1), the source strength of the neutron source and / or the sensitivity of the start detector are adjusted to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the start detector, and the initial parameters of the neutron source and the initial parameters of the start detector are updated.

[0237] The first control subunit is used to execute S303: based on the updated initial parameters of the neutron source and the initial parameters for starting the detector, calculate the neutron flux density corresponding to each operating condition, and control the aforementioned judgment subunit and adjustment subunit to execute S302 to S303.

[0238] Until the neutron flux density corresponding to each working condition satisfies formula (1), the corrected source strength of the neutron source is determined as the target source strength, and the corrected sensitivity of the activated detector is determined as the first sensitivity.

[0239] Optionally, the verification conditions for the fission neutron proportion threshold include the following formula (2):

[0240]

[0241] in, The first neutron flux density, This represents the second neutron flux density.

[0242] Optionally, the second adjustment module 703 mentioned above specifically includes:

[0243] The first determining unit is used to execute S401: determine the measurement range of neutron flux density and power level under the full operating conditions of the start detector;

[0244] The second determining unit is used to perform S402: determine the neutron flux density and power level measurement range of the power range detector under full operating conditions based on the initial parameters of the power range detector.

[0245] The second judgment unit is used to execute S403: based on the measurement range of neutron flux density and power level under full-operation conditions of the start-up detector and the measurement range of neutron flux density and power level under full-power operation conditions of the power range detector, determine whether the range of the start-up detector and the power range detector meets the range coverage continuity requirement.

[0246] The second control unit is configured to execute S404: when the ranges of the start-up detector and the power range detector do not meet the range coverage continuity requirement, adjust at least one of the sensitivity, position, power level measurement range of the power range detector, and power level measurement range of the start-up detector to obtain the corrected sensitivity, corrected position, corrected measurement range of the power range detector, and corrected measurement range of the start-up detector, and update the measurement range in the initial parameters of the power range detector and the start-up detector.

[0247] Control the second determining unit and the second judging unit to execute S402 to S404 until the range of the start detector and the power range detector meets the range coverage continuity, then determine the corrected sensitivity of the power range detector as the second sensitivity, determine the corrected position of the power range detector as the third position, determine the corrected power level measurement range of the power range detector as the target measurement range of the power range detector, and determine the corrected power level measurement range of the start detector as the target measurement range of the start detector.

[0248] Optionally, the second judgment unit described above is specifically used for:

[0249] The following formula (3) is used to determine whether the ranges of the start-up detector and the power range detector meet the range coverage continuity requirement:

[0250]

[0251] Wherein, ψt is the neutron flux density in the sensitive region of the detector when it is fully fueled and at full power, and ψp is the neutron flux density in the sensitive region of the power range detector when it is fully fueled and at full power. These represent the lower and upper limits of the neutron measurement range that will be activated by the detector. These are the lower and upper limits of the neutron measurement range in the power range detector, respectively.

[0252] Under the condition that the neutron flux density and power level measurement range of the start-up detector and the neutron flux density and power level measurement range of the power range detector are satisfied with formula (3), the range of the start-up detector and the power range detector are determined to satisfy the range coverage continuity.

[0253] If the measurement ranges of neutron flux density and power level under full operating conditions of the start-up detector and the power range detector do not satisfy formula (3), it is determined that the ranges of the start-up detector and the power range detector do not satisfy the range coverage continuity.

[0254] The detector setup for the microreactor in this embodiment ensures accurate nuclear monitoring data even in complex and harsh in-reactor environments by adjusting the initial parameters of the neutron source and detector. Through continuity verification and sensitivity adjustment, it ensures seamless coverage of the detector's measurement range and effective operation even under external structural interference, avoiding the blind zone problem common in traditional detectors. Parameter adjustments under different operating conditions ensure real-time and accurate monitoring of the microreactor's response, improving the continuity and accuracy of nuclear monitoring. Even under different operating states or environmental conditions, the detector reliably responds to neutron signals, providing stable data support.

[0255] Example 4:

[0256] This embodiment provides a microreactor core monitoring system for microreactors, the system comprising:

[0257] The detector setting device 700 for a micro-pile provided in any of the above embodiments is used to set a detector in a micro-pile;

[0258] The detection module is used to perform nuclear monitoring on the microreactor using a detector.

[0259] It should be clarified that this application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0260] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. Programs or code segments can be stored on a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried on a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0261] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0262] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable scheduling apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable scheduling apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0263] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method for setting up a detector in a miniature stack, characterized in that, The method includes: The core structure parameters and external structure parameters of the microreactor are obtained. The core structure parameters include the initial parameters of the neutron source, and the external structure parameters include the initial parameters of the start-up detector and the power range detector. Based on the count rate requirement and fission neutron proportion threshold of the detector under different operating conditions, the initial parameters of the neutron source and the initial parameters of the detector are adjusted to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector. By verifying the continuity of range coverage of the start-up detector and the power range detector, the initial parameters of the power range detector are adjusted to obtain the second sensitivity and the third position of the power range detector. The detector settings for the microreactor are configured based on the target source strength and first position of the neutron source, the first sensitivity and second position of the activation detector, and the second sensitivity and third position of the power range detector.

2. The method according to claim 1, characterized in that, The process of adjusting the initial parameters of the neutron source and the initial parameters of the detector based on the count rate requirements and fission neutron proportion threshold under different operating conditions to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the detector, specifically includes: S201. Calculate the neutron flux density for each operating condition based on the source strength of the neutron source and the location of the activated detector. S202. Based on the neutron flux density and the count rate requirement for activating the detector corresponding to each operating condition, the source strength of the neutron source and the sensitivity of the detector are adjusted to obtain the target source strength of the neutron source and the first sensitivity of the detector. The initial parameters of the neutron source and the initial parameters of the activated detector are updated based on the target source strength and the first sensitivity. S203. Based on the target source strength of the neutron source and the first sensitivity of the activation detector, calculate the first neutron flux density and the second neutron flux density. Wherein, the first neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is not considered in the third operating condition, and the second neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is considered in the third operating condition. The third operating condition is when the fuel is fully loaded and the core k eff Core condition ≈0.99; S204. If the first neutron flux density and the second neutron flux density do not meet the fission neutron proportion threshold verification condition, the position of the neutron source and the position of the activation detector are adjusted to obtain the corrected position of the neutron source and the corrected position of the activation detector, and the initial parameters of the neutron source and the initial parameters of the activation detector are updated. Return to execute steps S201~S204 until the first neutron flux density and the second neutron flux density meet the fission neutron proportion threshold verification condition, then determine the corrected position of the neutron source as the first position of the neutron source, and determine the corrected position of the activated detector as the second position.

3. The method according to claim 2, characterized in that, The step of adjusting the source strength of the neutron source and the sensitivity of the detector based on the neutron flux density and the count rate requirement for starting the detector under each operating condition to obtain the target source strength of the neutron source and the first sensitivity of the detector specifically includes: S301. Determine whether the neutron flux density corresponding to each working condition meets the count rate requirement for starting the detector according to formula (1): （1） Where Q is the source strength of the neutron source, and St is the sensitivity of activating the neutron detector. To calculate the uncertainty, Let N be the neutron flux density in the sensitive region of the detector under each neutron source strength, and let N be the count rate requirement for activating the neutron detector under each operating condition. S302. When the neutron flux density corresponding to each working condition does not satisfy formula (1), the source strength of the neutron source and / or the sensitivity of the start detector are adjusted to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the start detector, and the initial parameters of the neutron source and the initial parameters of the start detector are updated. S303. Based on the updated initial parameters of the neutron source and the initial parameters of the activated detector, calculate the neutron flux density corresponding to each operating condition, and return to execute S302~S303. Until the neutron flux density corresponding to each operating condition satisfies formula (1), the corrected source strength of the neutron source is determined as the target source strength, and the corrected sensitivity of the activated detector is determined as the first sensitivity.

4. The method according to claim 2, characterized in that, The verification condition for the fission neutron proportion threshold includes the following formula (2): in, The first neutron flux density, This represents the second neutron flux density.

5. The method according to claim 1, characterized in that, The step of verifying the continuity of range coverage of the activation detector and the power range detector, adjusting the initial parameters of the power range detector, and obtaining the second sensitivity and third position of the power range detector specifically includes: S401. Determine the measurement range of neutron flux density and power level under the full-power operation condition of the start-up detector; S402. Determine the neutron flux density and power level measurement range of the power range detector under full-power operation conditions. S403. Based on the measurement range of neutron flux density and power level under the full-power operation of the start-up detector and the measurement range of neutron flux density and power level under the full-power operation of the power range detector, determine whether the ranges of the start-up detector and the power range detector meet the range coverage continuity requirement. S404. If the ranges of the start-up detector and the power range detector do not meet the range coverage continuity requirement, at least one of the following is adjusted: the sensitivity, position, power level measurement range of the power range detector, and the power level measurement range of the start-up detector. This yields corrected sensitivity, corrected position, corrected measurement range of the power range detector, and corrected measurement range of the start-up detector. The initial parameters of the power range detector and the measurement range in the initial parameters of the start-up detector are then updated. Return to execute steps S402~S404 until the ranges of the start detector and the power range detector meet the range coverage continuity requirement. Then, determine the corrected sensitivity of the power range detector as the second sensitivity, determine the corrected position of the power range detector as the third position, determine the corrected measurement range of the power range detector as the target measurement range of the power range detector, and determine the corrected measurement range of the start detector as the target measurement range of the start detector.

6. The method according to claim 5, characterized in that, The step of determining whether the ranges of the start-up detector and the power range detector satisfy the range coverage continuity requirement based on the measurement ranges of the neutron flux density and power level under full-power operation of the start-up detector and the power range detector under full-power operation specifically includes: The range of the start-up detector and the power range detector is determined by the following formula (3) to determine whether the range coverage continuity is satisfied: （3） Wherein, ψt is the neutron flux density in the sensitive region of the detector when it is fully fueled and at full power, and ψp is the neutron flux density in the sensitive region of the power range detector when it is fully fueled and at full power. tmin, tmax represents the lower and upper limits of the neutron measurement range when the detector is activated. pmin, pmax represents the lower and upper limits of the measurement range of the neutron in the power range detector, respectively. If the neutron flux density and power level measurement ranges of the start-up detector and the power range detector are both at full power operation, and the neutron flux density and power level measurement ranges of the power range detector are at full power operation, respectively, and the ranges of the start-up detector and the power range detector are satisfied with the formula (3), then the ranges of the start-up detector and the power range detector are determined to satisfy the range coverage continuity. If the neutron flux density and power level measurement ranges under the full-power operation of the start-up detector and the full-power operation of the power range detector do not satisfy the formula (3), it is determined that the ranges of the start-up detector and the power range detector do not satisfy the range coverage continuity.

7. A nuclear monitoring method, characterized in that, The method includes: A detector is installed in the micro-pile using the detector installation method according to any one of claims 1 to 6; The detector is used to perform nuclear monitoring on the microreactor.

8. A detector setting device for a miniature stack, characterized in that, The device includes: The acquisition module is used to acquire the core structure parameters and external structure parameters of the microreactor. The core structure parameters include the initial parameters of the neutron source, and the external structure parameters include the initial parameters of the start-up detector and the power range detector. The first adjustment module, connected to the acquisition module, is used to adjust the initial parameters of the neutron source and the initial parameters of the start-up detector according to the count rate requirement and fission neutron ratio threshold of the start-up detector under different operating conditions, so as to obtain the target source strength and first position of the neutron source, and the first sensitivity and second position of the start-up detector. The second adjustment module, connected to the first adjustment module, is used to adjust the initial parameters of the power range detector by verifying the continuity of range coverage of the start detector and the power range detector, so as to obtain the second sensitivity and the third position of the power range detector. The setting module is connected to the first adjustment module and the second adjustment module respectively, and is used to set the detector of the microreactor according to the target source strength and first position of the neutron source, the first sensitivity and second position of the activation detector, and the second sensitivity and third position of the power range detector.

9. The apparatus according to claim 8, characterized in that, The first adjustment module includes: The first calculation unit is used to execute S201, calculate the neutron flux density corresponding to each working condition based on the source strength of the neutron source and the location of the detector activation, wherein the neutron flux density is the neutron flux density of the sensitive area of ​​the detector activation under unit neutron source strength; The first adjustment unit, connected to the first calculation unit, is used to execute S202, adjusting the source strength of the neutron source and the sensitivity of the detector activation based on the neutron flux density and the count rate requirement for each operating condition, to obtain the target source strength of the neutron source and the first sensitivity of the detector activation. The initial parameters of the neutron source and the initial parameters of the activated detector are updated based on the target source strength and the first sensitivity. The second calculation unit, connected to the first adjustment unit, is used to execute S203, calculating the first neutron flux density and the second neutron flux density based on the target source strength of the neutron source and the first sensitivity of the activated detector. Wherein, the first neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is not considered in the third operating condition, and the second neutron flux density is the neutron flux density of the detector sensitive area when fuel fission is considered in the third operating condition. The third operating condition is when the fuel is fully loaded and the core k eff Core condition ≈0.99; The second adjustment unit, connected to the second calculation unit, is used to execute S204: if the first neutron flux density and the second neutron flux density do not meet the fission neutron proportion threshold verification condition, adjust the position of the neutron source and the position of the activation detector to obtain the corrected position of the neutron source and the corrected position of the activation detector, and update the initial parameters of the neutron source and the initial parameters of the activation detector. The first calculation unit, the first adjustment unit, and the second calculation unit are controlled to execute S201~S204 until the first neutron flux density and the second neutron flux density meet the fission neutron ratio threshold verification condition. The corrected position of the neutron source is determined as the first position of the neutron source, and the corrected position of the activated detector is determined as the second position.

10. A nuclear monitoring system, characterized in that, The system includes: The detector placement device for a micro-pile according to any one of claims 8 to 9 is used to place a detector in the micro-pile; The detection module is used to perform nuclear monitoring on the microreactor using the detector.

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