Detector setting method and device of micro reactor, and nuclear monitoring method and system

Abstract

The invention discloses a micro reactor detector setting method and device, and a nuclear monitoring method and system. The detector setting method comprises the following steps: acquiring a reactor core structure parameter and an out-of-reactor structure parameter of a micro reactor; adjusting the initial parameters of the neutron source and the initial parameters of the starting detector according to the counting rate requirement and the fission neutron proportion threshold of the starting detector under different working conditions to obtain the target source intensity and the first position of the neutron source and the first sensitivity and the second position of the starting detector; adjusting an initial parameter of the power range detector by performing range coverage continuity verification on the starting detector and the power range detector to obtain a second sensitivity and a third position of the power range detector; and according to the target source intensity, the first position, the first sensitivity, the second position, the second sensitivity and the third position, carrying out detector setting on the micro reactor. Therefore, the accuracy and the continuity of monitoring the miniature reactor nucleus by the detector are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power, and particularly relates to a method and device for setting detectors of a micro reactor, a nuclear monitoring method and system. Background Art

[0002] Micro nuclear energy devices have a high energy density and can stably and cleanly provide energy such as electricity and heat sources, while minimizing logistics supply. However, these application scenarios have high requirements for the safe operation of micro nuclear energy devices, and nuclear monitoring is the basis for guiding the normal operation of the reactor, ensuring nuclear safety, achieving reactivity control and protection.

[0003] Nuclear monitoring generally measures relevant parameters such as neutron flux level, power level, and reactor period through neutron detectors to provide signals for reactor operation and protection. At the same time, there may also be control rod position measurement or water level measurement in a pressurized water reactor to assist in core monitoring.

[0004] However, due to the compact structure and harsh in-core environment (high temperature, high pressure, and high radiation) of the micro reactor, it is difficult to arrange traditional in-core detectors, and the out-of-core structure seriously interferes with neutron signals, easily resulting in monitoring blind spots and signal distortion. Therefore, the detectors provided by the prior art for micro reactors have insufficient accuracy and continuity for nuclear monitoring of the core. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and device for setting detectors of a micro reactor, a nuclear monitoring method and system in view of the above deficiencies existing in the prior art. The detectors obtained by using this detector setting method can be arranged in a traditional reactor and can improve the accuracy and continuity of nuclear monitoring of the micro reactor by the detectors.

[0006] In a first aspect, an embodiment of the present invention provides a method for setting detectors of a micro reactor. The gas-cooled micro reactor includes a plurality of fuel assemblies, and the method includes:

[0007] Obtain the in-core structure parameters and out-of-core structure parameters of the micro reactor. The in-core structure parameters include the initial parameters of the neutron source, and the out-of-core structure parameters include the initial parameters of the startup detector and the power range detector;

[0008] Adjust the initial parameters of the neutron source and the initial parameters of the startup detector according to the count rate requirements of the startup detector and the fission neutron ratio threshold under different working conditions to obtain the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector;

[0009] By performing continuous verification on the range coverage of the startup detector and the power range detector, adjusting the initial parameters of the power range detector, the second sensitivity and the third position of the power range detector are obtained.

[0010] According to the target source strength of the neutron source and the first position, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector, detector settings are performed on the miniature reactor.

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

[0012] S201. Calculate the neutron flux density corresponding to each working condition according to the source strength of the neutron source and the position of the startup detector, where the neutron flux density is the neutron flux density in the sensitive area of the startup detector under a unit neutron source strength.

[0013] S202. Adjust the source strength of the neutron source and the sensitivity of the startup detector according to the neutron flux density corresponding to each working condition and the count rate requirement of the startup detector to obtain the target source strength of the neutron source and the first sensitivity of the startup detector.

[0014] Update the initial parameters of the neutron source and the initial parameters of the startup detector according to the target source strength and the first sensitivity.

[0015] S203. Calculate the first neutron flux density and the second neutron flux density according to the target source strength of the neutron source and the first sensitivity of the startup detector.

[0016] Wherein, the first neutron flux density is the neutron flux density in the sensitive area of the startup detector without considering fuel fission under the third working condition, the second neutron flux density is the neutron flux density in the sensitive area of the startup detector considering fuel fission under the third working condition, and the third working condition is the core state with full fuel loading and the core k eff ≈0.99.

[0017] S204. In the case that 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 startup detector to obtain the corrected position of the neutron source and the corrected position of the startup detector, and update the initial parameters of the neutron source and the initial parameters of the startup detector.

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

[0019] Optionally, adjusting the source strength of the neutron source and the sensitivity of the startup detector according to the neutron flux density corresponding to each working condition and the counting rate requirement of the startup detector to obtain the target source strength of the neutron source and the first sensitivity of the startup detector specifically includes:

[0020] S301. Judge whether the neutron flux density corresponding to each working condition meets the counting rate requirement of the startup detector according to formula (1):

[0021]

[0022] where Q is the source strength of the neutron source, St is the sensitivity of the startup neutron detector, σ is the calculation uncertainty, is the neutron flux density in the sensitive area of the startup detector per unit source strength of the neutron source under each working condition, and N is the counting rate requirement of the startup neutron detector under each working condition;

[0023] S302. In the case that the neutron flux density corresponding to each working condition does not meet formula (1), adjust the source strength of the neutron source and / or the sensitivity of the startup detector to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the startup detector, and update the initial parameters of the neutron source and the initial parameters of the startup detector;

[0024] S303. Calculate the neutron flux density corresponding to each working condition according to the updated initial parameters of the neutron source and the initial parameters of the startup detector, and return to execute S302 to S303,

[0025] until the neutron flux density corresponding to each working condition meets formula (1), determine the corrected source strength of the neutron source as the target source strength, and determine the corrected sensitivity of the startup detector as the first sensitivity.

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

[0027]

[0028] where is the first neutron flux density, is the second neutron flux density.

[0029] Optionally, the initial parameters of the power range detector are adjusted by continuously verifying the range coverage of the startup detector and the power range detector to obtain the second sensitivity and the third position of the power range detector, specifically including:

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

[0031] S402. Determine the neutron flux density and the power level measurement range under the full power operation condition of the power range detector according to the initial parameters of the power range detector;

[0032] S403. Determine whether the ranges of the startup detector and the power range detector meet the range coverage continuity according to the neutron flux density and the power level measurement range under the full power operation condition of the startup detector and the neutron flux density and the power level measurement range under the full power operation condition of the power range detector;

[0033] S404. In the case where the ranges of the startup detector and the power range detector do not meet the range coverage continuity, at least one of the sensitivity, position, power level measurement range of the power range detector and the power level measurement range of the startup detector is adjusted to obtain the corrected sensitivity, corrected position, corrected measurement range of the power range detector and the corrected measurement range of the startup detector, and the measurement ranges in the initial parameters of the power range detector and the initial parameters of the startup detector are updated.

[0034] Return to execute S402 - S404 until the ranges of the startup detector and the power range detector meet the range coverage continuity. In this case, 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 startup detector as the target measurement range of the startup detector.

[0035] Optionally, the determination of whether the ranges of the startup detector and the power range detector meet the range coverage continuity according to the neutron flux density and the power level measurement range under the full power operation condition of the startup detector and the neutron flux density and the power level measurement range under the full power operation condition of the power range detector specifically includes:

[0036] Judge whether the ranges of the startup detector and the power range detector meet the range coverage continuity through the following formula (3):

[0037]

[0038] Wherein, ψt is the neutron flux density in the sensitive area of the startup detector when the fuel is fully loaded and operating at full power, and ψp is the neutron flux density in the sensitive area of the power range detector when the fuel is fully loaded and operating at full power. are respectively the lower limit and the upper limit of the neutron measurement range of the startup detector. are respectively the lower limit and the upper limit of the neutron measurement range of the power range detector;

[0039] When the neutron flux density and the power level measurement range under the full-power operation condition of the startup detector, and the neutron flux density and the power level measurement range under the full-power operation condition of the power range detector satisfy the formula (3), it is determined that the ranges of the startup detector and the power range detector satisfy the range coverage continuity.

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

[0041] In a second aspect, an embodiment of the present invention further provides a nuclear monitoring method, and the method includes:

[0042] Setting detectors in the micro reactor by the detector setting method of the micro reactor described in the first aspect;

[0043] Performing nuclear monitoring on the micro reactor by the detectors.

[0044] In a third aspect, an embodiment of the present invention further provides a detector setting device for a micro reactor, and the device includes:

[0045] An acquisition module, configured to acquire the core structure parameters and the out-of-core structure parameters of the micro reactor, where the core structure parameters include the initial parameters of the neutron source, and the out-of-core structure parameters include the initial parameters of the startup detector and the power range detector;

[0046] A first adjustment module, connected to the acquisition module, configured to adjust the initial parameters of the neutron source and the initial parameters of the startup detector according to the count rate requirement of the startup detector and the fission neutron ratio threshold under different working conditions, so as to obtain the target source strength and the first position of the neutron source, and the first sensitivity and the second position of the startup detector;

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

[0048] A setting module, connected to the first adjustment module and the second adjustment module respectively, is configured to perform detector setting on the micro reactor according to the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector.

[0049] Fourthly, an embodiment of the present invention further provides a nuclear monitoring system, and the system includes:

[0050] The detector setting device of the micro reactor described in the third aspect is configured to set detectors in the micro reactor;

[0051] A detection module is configured to perform nuclear monitoring on the micro reactor through the detector.

[0052] The detector setting method of the micro reactor of the present invention can adjust the source strength of the neutron source, the sensitivity and the setting position of the startup detector according to the counting rate requirement of the startup detector and the fission neutron proportion threshold, so as to ensure that the detector can still effectively monitor the nuclear state of the reactor in harsh environments such as high temperature, high pressure and high irradiation; by verifying the continuity of the range coverage of the startup detector and the power range detector, the sensitivity and the self position of the power range detector are further adjusted, so as to avoid monitoring blind areas or signal distortion of traditional detectors under the interference of complex external reactor structures. Therefore, the adaptability and accuracy of the detector under harsh conditions are improved, and high-precision and continuous monitoring of the micro reactor nuclear reactor is realized. Description of the Drawings

[0053] Figure 1 : A flowchart of a detector setting method for a micro reactor according to Embodiment 1 of the present invention;

[0054] Figure 2 : A flowchart of another detector setting method for a micro reactor according to Embodiment 1 of the present invention;

[0055] Figure 3 : A radial layout diagram of the core and nuclear monitoring system of the gas-cooled micro reactor according to Embodiment 1 of the present invention;

[0056] Figure 4 : An axial layout diagram of the core and nuclear monitoring system of the gas-cooled micro reactor according to Embodiment 1 of the present invention;

[0057] Figure 5 : A schematic structural diagram of the neutron detector according to Embodiment 1 of the present invention;

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

[0059] Figure 7 : It is the structure diagram of the detector setting device of a micro reactor in Embodiment 3 of the present invention.

[0060] The meanings of the marks in the figure are as follows:

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

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

[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 article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "including..." do not exclude the presence of additional identical elements in the process, method, article or device including the said elements.

[0065] Compared with the inaccessibility of the large power grid and the huge logistics requirements of diesel generators, the micro nuclear energy device has a high energy density and can stably and cleanly provide energy such as electricity and heat source, while minimizing the logistics supply. However, these application scenarios have high requirements for the safe operation of the micro nuclear energy device, and nuclear monitoring is the basis for guiding the normal operation of the reactor, ensuring nuclear safety, achieving reactivity control and protection.

[0066] Nuclear monitoring generally uses neutron detectors to measure neutron flux levels, power levels, reactor cycles and other related parameters to provide signals for reactor operation and protection. Control rod position measurement or water level measurement in pressurized water reactors may also be set up to assist in core monitoring. In commercial reactors, in addition to external source range detectors, intermediate range detectors, and power range detectors, mobile fission chamber in-core detectors are generally used in second-generation and "second-generation +" pressurized water reactors. Neutron measurement is independent of other measurement systems, and the full-core flux diagram is measured in time-sharing, which is time-consuming and has a large irradiation dose.

[0067] However, micro-reactors have a compact layout, small active area, complex structure, high core operating temperature, and harsh service environment for in-reactor instruments. They face problems such as high temperature, high pressure, high radiation, and narrow space. It is difficult to find a suitable type of in-reactor detector. In addition, inspection and maintenance are also difficult. Pebble bed high temperature gas-cooled reactor nuclear power plants solve the problem of not being able to arrange detectors in fuel assemblies by arranging detectors in side reflectors. However, the micro-reactor reactor system is compact, and it is difficult to open too many operating channels in the pressure vessel. In addition, the micro-reactor reflector layer is thin and the reflector layer temperature of the micro high temperature gas-cooled reactor is also very high, which can easily exceed the detector operating temperature limit. At present, there is no built mobile micro-reactor, and there is no mature micro-reactor nuclear monitoring method and system that can be directly applied.

[0068] Embodiment 1:

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

[0070] Specifically, the following steps are included from step 101 to step 104 .

[0071] Step 101, obtaining core structure parameters and external structure parameters of the micro reactor, wherein the core structure parameters include initial parameters of the neutron source.

[0072] Among them, the external pile structure parameters include the initial parameters of the startup detector and the power range detector.

[0073] Core structure parameters: including the initial parameters of the neutron source, that is, the initial state of the neutron source in the core of the nuclear reactor of the micro-reactor (for example, source intensity, energy spectrum, etc.). External structure parameters: involving the initial parameters of the start-up detector and the power range detector. The external structure usually affects the signal reception of the detector, especially the propagation and capture of the neutron signal.

[0074] Specifically, the core structure parameters of the micro-reactor (such as the size of the fuel assembly, the thickness of the reflector, the position of the control rod, the initial position and source strength of the neutron source) and the out-of-core structure parameters (such as the thickness of the shielding layer, the size of the pressure vessel, the initial position and sensitivity of the startup detector and power range detector) can be obtained through design drawings, Monte Carlo simulations or experimental measurements.

[0075] A three-dimensional modeling tool (such as CAD) can be used to construct a core geometry model, and the neutron transport characteristics can be defined in combination with a material database (such as ENDF / B) to provide basic data for subsequent simulations.

[0076] Step 102: According to the counting rate requirements of the startup detector and the fission neutron ratio threshold under different working conditions, adjust the initial parameters of the neutron source and the initial parameters of the startup detector to obtain the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector.

[0077] The fission neutron ratio threshold is a key parameter for judging whether the detector can effectively detect the core reaction, and it reflects the effectiveness of fission neutrons on the detector response.

[0078] Specifically, adjust the initial parameters of the neutron source and the startup detector according to the counting rate requirements of the startup detector and the fission neutron ratio threshold under different working conditions. By adjusting the initial parameters of the neutron source, that is, selecting a suitable neutron source (the neutron source strength and energy spectrum distribution of which meet the target source strength) and determining the installation position of the neutron source (i.e., the first position), so as to ensure that the detector can obtain sufficient signal strength under different working conditions; by adjusting the sensitivity (i.e., selecting a detector with appropriate sensitivity) and installation position (i.e., the second position) of the startup detector, to ensure that the detector can effectively respond to the neutron signal of the micro-reactor.

[0079] Step 103: Through the continuity verification of the range coverage of the startup detector and the power range detector, adjust the initial parameters of the power range detector to obtain the second sensitivity and the third position of the power range detector.

[0080] Specifically, conduct the continuity verification of the range coverage of the startup detector and the power range detector, and adjust the initial parameters of the power range detector to determine a more appropriate sensitivity and position of the power range detector, so as to ensure that under different power outputs and detection conditions, the ranges and detection capabilities of the startup detector and the power range detector can be seamlessly connected to avoid monitoring blind spots.

[0081] Step 104: According to the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector, perform detector settings for the micro-reactor.

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

[0083] In this embodiment, by adjusting the initial parameters of the neutron source and the detector, it is ensured that accurate nuclear monitoring data can still be obtained even in the case of a complex and harsh in-reactor environment; through continuous verification and sensitivity adjustment, it is ensured that the range coverage of the detector is seamlessly connected, and the detector can effectively work under the condition of external reactor structure interference, avoiding the blind area problem that traditional detectors are prone to. According to the parameter adjustment under different operating conditions, it is ensured that the detector can monitor the response of the micro reactor in real time and accurately, improving the continuity and accuracy of nuclear monitoring. Even under different operating states or environmental conditions, the detector can reliably respond to neutron signals and provide stable data support.

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

[0085] S201. Calculate the neutron flux density corresponding to each operating condition according to the source strength of the neutron source and the position of the start-up detector. The neutron flux density is the neutron flux density in the sensitive area of the start-up detector under a unit neutron source strength;

[0086] S202. Adjust the source strength of the neutron source and the sensitivity of the start-up detector according to the neutron flux density corresponding to each operating condition and the count rate requirement of the start-up detector to obtain the target source strength of the neutron source and the first sensitivity of the start-up detector,

[0087] Update the initial parameters of the neutron source and the initial parameters of the start-up detector according to the target source strength and the first sensitivity;

[0088] S203. Calculate the first neutron flux density and the second neutron flux density according to the target source strength of the neutron source and the first sensitivity of the start-up detector,

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

[0090] S204. In the case where the first neutron flux density and the second neutron flux density do not meet the verification condition of the fission neutron proportion threshold, adjust the position of the neutron source and the position of the start-up detector to obtain the corrected position of the neutron source and the corrected position of the start-up detector, and update the initial parameters of the neutron source and the initial parameters of the start-up detector,

[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, determine the corrected position of the neutron source as the first position of the neutron source, and determine the corrected position of the start detector as the second position.

[0092] Among them, the operating conditions of the micro-reactor can be divided into the following four operating conditions:

[0093] The first operating condition: no fuel core, and the counting rate requirement is N1.

[0094] The second operating condition: completely shutdown, fuel is loaded but 0 < k eff < 0.99, and the neutron counting rate requirement is N2;

[0095] The third operating condition: k eff ≈ 0.99, fuel is loaded and the subcritical state is set, and the neutron counting rate requirement is N3.

[0096] The fourth operating condition: full power operation.

[0097] Specifically, first, in S201, according to the source strength of the neutron source and the position of the start detector through Monte Carlo simulation, the neutron flux density of the start detector under each operating condition is obtained;

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

[0099] For S203, evaluate the performance of the start detector under different operating conditions, especially consider the neutron flux difference when the fuel fissions and when it does not fission, analyze the different effects of fission neutrons and non-fission neutrons on the detector response, so as to provide data support for the next step of judging whether the fission neutron proportion threshold is met.

[0100] For S204, if the first neutron flux density and the second neutron flux density do not meet the fission neutron ratio threshold verification condition, the positions of the neutron source and the startup detector need to be adjusted. By modifying the position of the detector, the capture efficiency of the neutron signal can be optimized, the interference of the out-of-core structure can be reduced, and thus the accuracy of the signal can be improved. After the adjustment, the calculations and verifications of S201 to S203 are performed again. Through repeated adjustments until the fission neutron ratio threshold is met. Finally, the corrected position of the neutron source is determined as the first position, the corrected position of the startup 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 startup detector, the counting rate requirement of the startup detector can be met under each working condition, ensuring that the neutron signals of the microreactor can be effectively monitored under different working conditions; through position adjustment and parameter update, the problem of the interference of the out-of-core structure on the neutron signal is solved, enabling the position layout of the neutron source and the detector to better adapt to the specific environment of the microreactor, avoiding blind spots and signal weakening, and enhancing the stability and adaptability of the detector under harsh conditions. Thereby, the monitoring accuracy and continuity of the microreactor nuclear reactor are improved, providing a more reliable technical guarantee for the safe operation of the microreactor.

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

[0103] S301. Determine whether the neutron flux density corresponding to each working condition meets the counting rate requirement of the startup detector according to formula (1):

[0104]

[0105] where Q is the source strength of the neutron source, St is the sensitivity of the startup neutron detector, σ is the calculation uncertainty, is the neutron flux density in the sensitive area of the startup detector per unit source strength of the neutron source under each working condition, and N is the counting rate requirement of the startup neutron detector under each working condition;

[0106] S302. In the case where the neutron flux density corresponding to each working condition does not meet formula (1), adjust the source strength of the neutron source and / or the sensitivity of the startup detector to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the startup detector, and update the initial parameters of the neutron source and the initial parameters of the startup detector;

[0107] S303. Calculate the neutron flux density corresponding to each working condition according to the updated initial parameters of the neutron source and the initial parameters of the startup detector, 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, it is judged according to formula (1) whether the neutron flux density corresponding to each working condition meets the count rate requirement of the corresponding activated detector.

[0110] For S302, if the neutron flux density under a certain working condition does not meet the requirement of formula (1), adjust the source strength of the neutron source and / or the sensitivity of the activated detector to meet the requirement. In S301, if it is determined that the neutron flux density under a certain working condition does not meet the requirement, it is necessary to adjust the source strength Q of the neutron source or the sensitivity St of the activated detector. According to the actual situation, it is possible to choose to adjust the source strength, the sensitivity, or both at the same time. The corrected source strength of the neutron source and / or the corrected sensitivity after adjustment update the initial parameters to ensure that the new settings can meet the count rate requirement and maintain the accuracy of the detector.

[0111] For S303, recalculate the neutron flux density under each working condition for the adjusted neutron source strength and the sensitivity of the activated detector to ensure that the count rate requirement is met. According to the adjusted neutron source strength and the sensitivity of the activated detector, recalculate the neutron flux density under each working condition to check whether it meets the requirement in formula (1). If the flux density still does not meet the requirement after adjustment, then perform the adjustment of S302 again until the neutron flux density of each working condition meets the count rate requirement to reach the final corrected source strength and sensitivity values.

[0112] In this embodiment, iterative adjustment is performed according to formula (1) to ensure that the neutron flux density under each working condition meets the count rate requirement of the activated detector. It is possible to dynamically adjust the source strength of the neutron source and the sensitivity of the activated detector to ensure that the system can always respond accurately under various working conditions. Maximize the sensitivity and response ability of the activated detector under different working conditions, avoid detection errors caused by environmental changes or inappropriate parameters, optimize the parameters of the neutron source and the detector, and make the neutron monitoring of nuclear reactors such as microreactors more accurate during actual operation.

[0113] Optionally, the above-mentioned fission neutron ratio threshold verification condition includes the following formula (2):

[0114]

[0115] where, is the first neutron flux density, that is, under the working condition (the third working condition) where the fuel is fully loaded and the core k eff ≈0.99, the fuel fission reaction can be closed through Monte Carlo simulation, and only the contributions of the neutron source and non-fission neutrons (such as scattering, absorption) are calculated.

[0116] is the second neutron flux density. Under the same operating condition (the third operating condition), the fuel fission reaction is initiated, and the total neutron flux density (including the comprehensive contributions of neutron sources, fission neutrons, and non-fission neutrons) is calculated.

[0117] Specifically, formula (2) ensures that the core monitored by the detector is 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. Through the verification of the proportion of fission neutrons (>95%), the interference of the out-of-core structure on the neutron signal is effectively excluded, and the signal-to-noise ratio of the monitoring data is improved.

[0118] Since the neutron flux span of the microreactor from loading to full-power operation is extremely large, a single detector cannot cover the entire range. Therefore, a complementary design of a startup detector (high sensitivity, low range) and a power range detector (wide range, high upper limit) can be adopted to ensure blind-free monitoring under all operating conditions.

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

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

[0121] S402. Determine the neutron flux density and power level measurement range under the full-power operation condition of the power range detector according to the initial parameters of the power range detector;

[0122] S403. Determine whether the ranges of the startup detector and the power range detector satisfy the range coverage continuity according to the neutron flux density and power level measurement range under the full-power operation condition of the startup detector and the neutron flux density and power level measurement range under the full-power operation condition of the power range detector;

[0123] S404. In the case where the ranges of the startup detector and the power range detector do not satisfy the range coverage continuity, at least one of the sensitivity, position, power level measurement range of the power range detector, and the power level measurement range of the startup detector is adjusted to obtain the corrected sensitivity, corrected position, corrected measurement range of the power range detector, and the corrected measurement range of the startup detector, and the measurement ranges in the initial parameters of the power range detector and the initial parameters of the startup detector are updated.

[0124] Return to execute the steps S402 to S404 until the ranges of the start-up detector and the power range detector satisfy 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 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-up detector as the target measurement range of the start-up detector.

[0125] In this embodiment, first, it is necessary to determine the neutron flux density and the power level measurement range under the full-power operation condition (the fourth condition) of the start-up detector. Then, according to the initial parameters of the power range detector, determine its corresponding parameters under the full-power operation condition. Then, judge whether the coverage continuity requirement is met by comparing the ranges of the two. If not, adjust the sensitivity or position of the power range detector and repeat the verification until the condition is met.

[0126] Specifically, for S401, a core model under the full-power operation condition can be constructed through Monte Carlo simulation (such as MCNP or Serpent), load the actual fuel assembly and set the thermal parameters (such as coolant temperature, pressure), simulate the neutron transport process, and output the neutron flux density in the sensitive area of the start-up detector. According to the sensitivity and range index 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, calculate the neutron flux density of the power range detector under the full-power condition through Monte Carlo simulation. And determine the range according to its technical index.

[0128] For S403, through the neutron flux density and measurement range of the start-up detector and the power range detector under the full-power condition, verify whether there is overlap or continuity in the range coverage of the two. That is, it is necessary to judge whether the start-up detector and the power range detector have overlapping ranges throughout the power range.

[0129] For S404, if there is discontinuity or insufficient overlap in the range coverage (i.e., the range coverage continuity is not satisfied), at least one of the sensitivity, position of the power range detector, and the power level measurement range of the power range detector and the startup detector needs to be adjusted so that the ranges of the power range detector and the startup detector continuously cover. Adjusting the parameters of the power range detector can be adjusting its sensitivity (denoted as replacing the detector with other sensitivities, thereby changing the detector's response ability to neutron flux), or 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 startup detector can also be adjusted. After adjustment, the initial parameters of the power range detector or the startup detector need to be updated, and the loop of S402 - S404 is returned until the range meets the requirements of range coverage continuity. The corrected sensitivity and corrected position of the power range detector are determined as the second sensitivity and the third position of the power range detector, and the corrected range of the startup detector or the power range detector is determined as the target measurement range of the two detectors.

[0130] In this embodiment, through the continuity verification mechanism, the parameter configuration of the power range detector is optimized so that the startup detector and the power range detector can cover the entire measurement range. It ensures that the range coverage of the startup detector and the power range detector always maintains continuity. The measurement range of the detector is optimized to ensure that the system can accurately respond in each power range.

[0131] Optionally, judging whether the ranges of the startup detector and the power range detector meet the range coverage continuity according to the neutron flux density and power level measurement range under the full operating condition of the startup detector, and the neutron flux density and power level measurement range under the full power operating condition of the power range detector specifically includes:

[0132] Judging whether the ranges of the startup detector and the power range detector meet the range coverage continuity through the following formula (3):

[0133]

[0134] Where ψt is the neutron flux density in the sensitive area of the startup detector when the fuel is fully loaded and operating at full power, ψp is the neutron flux density in the sensitive area of the power range detector when the fuel is fully loaded and operating at full power, are respectively the lower and upper limits of the neutron measurement range of the startup detector, are respectively the lower and upper limits of the neutron measurement range of the power range detector;

[0135] Under the condition that the neutron flux density and power level measurement ranges of the startup detector under full operating conditions and the neutron flux density and power level measurement ranges of the power range detector under full operating conditions satisfy formula (3), determine that the ranges of the startup detector and the power range detector meet the continuity of range coverage;

[0136] Under the condition that the neutron flux density and power level measurement ranges of the startup detector under full operating conditions and the neutron flux density and power level measurement ranges of the power range detector under full operating conditions do not satisfy formula (3), determine that the ranges of the startup detector and the power range detector do not meet the continuity of range coverage.

[0137] Among them, the detector range is determined according to the detector technical specifications. The continuity of range coverage means that the measurement ranges of the two detectors under different power conditions can be seamlessly connected, without overlapping or blank areas, ensuring that the system can work properly throughout the measurement range.

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

[0139] Embodiment 2: This embodiment provides a nuclear monitoring method applied to a micro reactor, which specifically includes:

[0140] Set detectors in the micro reactor by using the detector setting method of the micro reactor provided in any of the above embodiments;

[0141] Perform nuclear monitoring on the micro reactor through the detectors.

[0142] Specifically, by combining the detector setting method of the above micro reactor, design the detectors for the micro reactor, and then perform nuclear monitoring on the micro reactor through the set detectors. Solve the range coverage problem in the micro reactor monitoring, ensure that the detectors can achieve accurate monitoring under various power conditions in the reactor, and thus improve the safety, stability and operation efficiency of the micro reactor.

[0143] To facilitate the understanding of the detector setting method of the micro reactor provided in this embodiment, the actual application description of the above method is provided here.

[0144] Taking a typical gas-cooled micro reactor as an example, a typical gas-cooled micro reactor core model is as Figure 3 and Figure 4As shown in the figure, the reactor core consists of hexagonal fuel assemblies 6 with the same geometric structure in the active zone, control rod assemblies (the first set of control rods 9 and the second set of control rods 8), and a reflector layer 5. Outside the reactor core, there are boron carbide bricks 4, a pressure vessel 3, a shielding and thermal insulation layer 2, a carriage frame 1, a neutron source 7, etc. There are 12 columns of fuel assemblies radially in the reactor core, and each column of assemblies has 3 layers of fuel assemblies axially. Therefore, there are 36 fuel assemblies in the whole reactor. There are two sets of control rods arranged. The first set of control rods 9 is located outside the active zone and has 6 groups of control rods, which are used for reactor core operation control, cold shutdown, hot shutdown, emergency shutdown, etc.; the second set of control rods 8 is located in the center of the reactor core and has 1 group of control rods, which is used as a backup shutdown means. Only when the first set of control rods cannot shut down the reactor, the reactor core can be hot shutdown.

[0145] Since the main cause of the detector nuclear signal is thermal neutrons, and thermal neutrons are extremely vulnerable to the effects of scattering, absorption, etc. of the boron carbide bricks 4, pressure vessel 3, and shielding and thermal insulation layer 2 outside the reactor, the thermal neutron signal measured by the detector cannot accurately reflect the state of the reactor core. To avoid the complex structure outside the reactor interfering with the detector's monitoring of neutrons, as Figure 5 shown in the figure, a cadmium layer is arranged around the structures such as the sensitive area of the detector to absorb thermal neutrons, and a polyethylene layer is arranged to slow down fast neutrons. Finally, by monitoring fast neutrons, the influence of the structure outside the reactor on the neutron count of the detector can be avoided.

[0146] Analysis of nuclear monitoring methods is carried out for the typical gas-cooled micro-reactor core. The specific implementation steps are as Figure 2 shown:

[0147] S21. Obtain the loading of the micro-reactor core and the structure outside the reactor.

[0148] In the initial stage of design, first establish the reactor core model of the micro-reactor and the related detector model. This process includes the arrangement of fuel assemblies in the reactor core, the configuration of structures outside the reactor (such as shielding layers and pressure vessels, etc.), and the position design of the starting detector. Provide a basic model for subsequent calculations and parameter determination.

[0149] Specifically, (1) Obtain the loading scheme of the micro-reactor core and parameters such as the size and material of the structure outside the reactor:

[0150] Reactor core geometric parameters: including fuel assembly size, reflector thickness, control rod position, etc.

[0151] Material composition: fuel type (such as hexagonal fuel assemblies), moderator (graphite), coolant (gas), shielding layer (boron carbide bricks), etc.

[0152] Parameters of the structure outside the reactor: pressure vessel size, shielding and thermal insulation layer thickness, etc.

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

[0154] Model building: Use a Monte Carlo program to establish a three-dimensional core model, and replace the positions of fuel assemblies with graphite blocks.

[0155] Embed a neutron source: Define the initial position of the neutron source (such as the core center or within the reflector).

[0156] Embed a startup detector: Preliminarily set the position of the startup detector (such as outside the out-of-core shielding layer).

[0157] Output parameters: Generate the neutron flux distribution in the state without fuel.

[0158] S23. Establish a three-dimensional core and out-of-core structure model with full fuel loading.

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

[0160] Embed power range detectors: Preliminarily set the positions of power range detectors (such as multi-layer axial arrangement outside the core).

[0161] Output parameters: Generate the neutron flux distribution and k eff value in the state with full fuel.

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

[0163] S241. Define operating conditions.

[0164] Operating condition 1: Core state without fuel loading, with a required neutron count rate of N1;

[0165] Operating condition 2: Core state with full fuel loading and complete shutdown, with a required neutron count rate of N2;

[0166] Operating condition 3: Core state with full fuel loading and k eff ≈ 0.99, with a required neutron count rate of N3;

[0167] Operating condition 4: Full power operation.

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

[0169] The corresponding values under each operating condition can be obtained through Monte Carlo simulation.

[0170] S243. Judge whether the neutron source strength and the sensitivity of the startup detector satisfy the following formula (1) in the cases of operating conditions 1 to 3.

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

[0172]

[0173] In the formula,

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

[0175] St is the sensitivity of the start neutron detector;

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

[0177] is the neutron flux density in the sensitive area of the start neutron detector at unit neutron source strength under each working condition;

[0178] N is the count rate requirement of the start neutron detector under each working condition.

[0179] If, in the cases of working conditions 1 to 3, the neutron source strength and the sensitivity of the start detector both satisfy formula (1), then go to S25;

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

[0181] Table 1 is an example of the sensitivity requirements of the start detector under different working conditions. Therefore, when an americium-beryllium source with a source strength of 5.0E+06 n / s is selected for the neutron source, a pulse-type neutron detector with a sensitivity of 100 cps / flux can be selected for the start detector.

[0182] Table 1 Sensitivity Requirements of Start Detector under Different Working Conditions

[0183]

[0184] S25. Determine the positions of the neutron source and the start detector.

[0185] S251. Calculate the neutron flux density in the sensitive area of the start detector when considering and not considering fission under working condition 3 and

[0186] S252. Judge and Whether it satisfies formula (2).

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

[0188]

[0189] In the formula, For the full loading of the fuel assembly, and when the core k eff ≈ 0.99, and without considering the neutron reaction of fuel fission, the neutron flux density in the sensitive area of the startup detector;

[0190] For the full loading of the fuel assembly, and when the core k eff ≈ 0.99, and considering various neutron reactions such as fuel fission, the neutron flux density in the sensitive area of the startup detector;

[0191] If and satisfy formula (2), then go to S26;

[0192] If and do not satisfy formula (2), then adjust the positions of the neutron source and the startup detector, and return to execute S242 - S252.

[0193] In one example, the obtained positions of the neutron source and the startup detector are as shown in Figure 3 and Figure 4 . The neutron source is located inside the reactor, radially on the central graphite block assembly of the core, and axially 15 cm deep into the active area from the coolant inlet side. The startup detector is radially located outside the in - reactor shielding and thermal insulation layer and inside the carriage frame, and axially aligned with the third - layer fuel assembly. The calculation results show that among the measured neutrons, the proportion of fission neutrons is 97.6%, meeting the design requirements.

[0194] S26. Determine the detector range.

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

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

[0197] S263. Calculate the power level measurement ranges of the startup detector and the power range detector under operating condition four and

[0198] S264. Determine whether the power level measurement ranges of the startup detector and the power range detector satisfy formula (3).

[0199]

[0200] In the formula,

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

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

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

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

[0205] If the power level measurement ranges of the startup detector and the power range detector satisfy formula (3), then output the neutron source intensity, the sensitivity of the startup detector, the positions of the neutron source and the startup detector, as well as the position and sensitivity of the power range detector of the power range detector;

[0206] If the power level measurement ranges of the startup detector and the power range detector do not satisfy 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 ranges of the startup detector and the power range detector, and return to execute S261~S263.

[0207] In one example, as Figure 6 shown, Figure 6 is the range coverage diagram of the power measurement ranges of the startup detector and the power range detector. It can be seen that the startup detector can measure as low as 3.3E-11 * full power, which is much lower than the power level of the Doppler heating point. The power range detector can measure up to 60 * full power. There is a range coverage of more than two orders of magnitude between the two types of detectors, and the monitoring from 3.3E-11 * full power to 60 * full power level can be achieved, which can ensure that the reactor core is always within the monitored range.

[0208] In another example, the present application provides a gas-cooled micro reactor nuclear measurement system. The nuclear measurement system includes the above-mentioned americium-beryllium neutron source, startup detector, power range detector, and supporting auxiliary circuits, signal processors, and computer memories.

[0209] Based on meeting environmental condition restrictions such as temperature, the neutron source can be located within the core active zone, within the reflector, or outside the reactor.

[0210] The startup detector is a source range pulse-type neutron detector, with multiple groups arranged. Based on meeting environmental condition restrictions such as temperature, it can be located inside the core of the micro-reactor or outside the core of the micro-reactor.

[0211] For example, there are 2 groups of pulse-type neutron detectors arranged for the startup detector, with 1 neutron proportional counter tube in each group. The startup detector is radially located outside the out-of-pile shielding and thermal insulation layer and inside the carriage frame, and is axially aligned with the third-layer fuel assembly.

[0212] The power range detector is a wide-range current-type neutron detector, with multiple groups arranged, and multiple detectors are arranged at different axial heights in each group. Based on meeting environmental condition restrictions such as temperature, the power range detector can be located inside the core of the micro-reactor or outside the core of the micro-reactor.

[0213] For example, there are 3 groups of current-type neutron detectors arranged for the power range detector, and 4 γ-compensated ionization chambers are arranged at different axial heights in each group. The power range detector is radially located outside the out-of-pile shielding and thermal insulation layer and inside the carriage frame, and is approximately flush with the core active zone axially.

[0214] A layer of absorber layer and a layer of strong moderator layer are arranged around the sensitive area of the startup detector. The materials of the absorber layer include but are not limited to cadmium, boron, and gadolinium, and the materials of the strong moderator layer include but are not limited to polyethylene.

[0215] A layer of absorber layer and a layer of strong moderator layer are arranged around the sensitive area of the power range detector. The materials of the absorber layer include but are not limited to cadmium, boron, and gadolinium, and the materials of the strong moderator layer include but are not limited to polyethylene.

[0216] This gas-cooled micro-reactor nuclear monitoring system can ensure that the core of the gas-cooled micro-reactor is always within the neutron monitoring range during refueling, reactor startup, and operation, avoiding monitoring blind spots and unknown core states, and also avoiding similar problems of excessive detector range overlap in pressurized water reactors. It solves the problem of the lack of a mature core monitoring system faced by micro-reactors, provides nuclear measurement signal support for the operation control and nuclear safety of micro-reactors, and is of great significance for the research and development of micro-reactors.

[0217] The embodiments of the present application can use a pulsed source range detector as the startup detector and a wide-range current detector as the power range detector, and realize neutron monitoring throughout the whole process of refueling, startup and operation of the micro-reactor through a nuclear monitoring method that couples the neutron source, startup detector and power range detector, avoiding monitoring blind spots and unknown core states, and also avoiding similar problems of excessive detector range overlap in pressurized water reactors. By arranging an absorber layer and a strong moderation layer around the detector, the monitoring of fast neutrons in the core is realized, and excessive interference of complex out-of-core structures on neutron monitoring is avoided. The present invention solves the problem that it is difficult to monitor the core nuclear characteristics of a micro-reactor due to its compact layout, unsuitability for arranging a large number of in-core detectors, and lack of a mature nuclear monitoring system. Without destroying the compact layout of the micro-reactor, it provides nuclear measurement signal support for the operation control and nuclear safety of the micro-reactor, which is of great significance for the realization of functions such as core monitoring, intelligent operation, remote monitoring, and safe shutdown of the micro-reactor product, and provides an engineering implementation guarantee for the research and development of the micro-reactor product.

[0218] Embodiment 3:

[0219] As Figure 7 shown, this embodiment provides a detector setting device 700 for a micro-reactor, and the device includes:

[0220] An acquisition module 701, configured to acquire the core structure parameters and out-of-core structure parameters of the micro-reactor, where the core structure parameters include the initial parameters of the neutron source, and the out-of-core structure parameters include the initial parameters of the startup detector and the power range detector;

[0221] A first adjustment module 702, connected to the acquisition module 701, configured to adjust the initial parameters of the neutron source and the initial parameters of the startup detector according to the counting rate requirement of the startup detector and the fission neutron proportion threshold under different working conditions, to obtain the target source strength and the first position of the neutron source, and the first sensitivity and the second position of the startup detector;

[0222] A second adjustment module 703, connected to the first adjustment module 702, configured to adjust the initial parameters of the power range detector by verifying the continuity of the range coverage of the startup detector and the power range detector, to obtain the second sensitivity and the third position of the power range detector;

[0223] A setting module 704, respectively connected to the first adjustment module 702 and the second adjustment module 703, configured to perform detector setting on the micro-reactor according to the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector.

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

[0225] The first calculation unit is configured to execute S201: Calculate the neutron flux density corresponding to each working condition according to the source strength of the neutron source and the position of the start-up detector. The neutron flux density is the neutron flux density in the sensitive area of the start-up detector under a unit neutron source strength;

[0226] The first adjustment unit, connected to the first calculation unit, is configured to execute S202: Adjust the source strength of the neutron source and the sensitivity of the start-up detector according to the neutron flux density corresponding to each working condition and the count rate requirement of the start-up detector, so as to obtain the target source strength of the neutron source and the first sensitivity of the start-up detector.

[0227] Update the initial parameters of the neutron source and the initial parameters of the start-up detector according to the target source strength and the first sensitivity;

[0228] The second calculation unit, connected to the first adjustment unit, is configured to execute S203: Calculate the first neutron flux density and the second neutron flux density according to the target source strength of the neutron source and the first sensitivity of the start-up detector.

[0229] Wherein, the first neutron flux density is the neutron flux density in the sensitive area of the start-up detector without considering fuel fission under the third working condition, and the second neutron flux density is the neutron flux density in the sensitive area of the start-up detector considering fuel fission under the third working condition. The third working condition is the core state with full fuel loading and the core k eff ≈0.99;

[0230] The second adjustment unit, connected to the second calculation unit, is configured to execute S204: In the case that the first neutron flux density and the second neutron flux density do not meet the verification condition of the fission neutron ratio threshold, adjust the position of the neutron source and the position of the start-up detector to obtain the corrected position of the neutron source and the corrected position of the start-up detector, and update the initial parameters of the neutron source and the initial parameters of the start-up detector.

[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 verification condition of the fission neutron ratio threshold, and determine the corrected position of the neutron source as the first position of the neutron source and the corrected position of the start-up detector as the second position.

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

[0233] The first judgment subunit is configured to execute S301: Judge whether the neutron flux density corresponding to each working condition meets the count rate requirement of the start-up detector according to formula (1):

[0234]

[0235] Wherein, Q is the source strength of the neutron source, St is the sensitivity of the startup neutron detector, σ is the calculation uncertainty, is the neutron flux density in the sensitive area of the startup detector at unit neutron source strength under each working condition, and N is the count rate requirement of the startup neutron detector under each working condition;

[0236] The first adjustment subunit is used to execute S302: When the neutron flux density corresponding to each working condition does not satisfy formula (1), adjust the source strength of the neutron source and / or the sensitivity of the startup detector to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the startup detector, and update the initial parameters of the neutron source and the initial parameters of the startup detector;

[0237] The first control subunit is used to execute S303: Calculate the neutron flux density corresponding to each working condition according to the updated initial parameters of the neutron source and the initial parameters of the startup detector, and control the above-mentioned judgment subunit and adjustment subunit to execute S302 - S303,

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

[0239] Optionally, the fission neutron proportion threshold verification condition includes the following formula (2):

[0240]

[0241] Wherein, is the first neutron flux density, is the second neutron flux density.

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

[0243] The first determination unit is used to execute S401: Determine the neutron flux density and power level measurement range under the full operating condition of the startup detector;

[0244] The second determination unit is used to execute S402: Determine the neutron flux density and power level measurement range under the full operating condition of the power range detector according to the initial parameters of the power range detector;

[0245] The second judgment unit is used to execute S403: Judge whether the ranges of the startup detector and the power range detector satisfy the range coverage continuity according to the neutron flux density and power level measurement range under the full operating condition of the startup detector, and the neutron flux density and power level measurement range under the full power operating condition of the power range detector;

[0246] A second control unit, configured to execute S404: when the ranges of the startup detector and the power range detector do not satisfy range coverage continuity, adjust at least one of the sensitivity, position, power level measurement range of the power range detector, and the power level measurement range of the startup detector, to obtain the corrected sensitivity, corrected position, corrected measurement range of the power range detector, and the corrected measurement range of the startup detector, and update the measurement ranges in the initial parameters of the power range detector and the initial parameters of the startup detector.

[0247] Control the second determination unit and the second judgment unit to execute S402 to S404. Until the ranges of the startup detector and the power range detector satisfy range coverage continuity, 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 startup detector as the target measurement range of the startup detector.

[0248] Optionally, the above second judgment unit is specifically configured to:

[0249] Judge whether the ranges of the startup detector and the power range detector satisfy range coverage continuity through the following formula (3):

[0250]

[0251] where ψt is the neutron flux density in the sensitive region of the startup detector when the fuel is fully loaded and operating at full power, ψp is the neutron flux density in the sensitive region of the power range detector when the fuel is fully loaded and operating at full power, are respectively the lower and upper limits of the neutron measurement range of the startup detector, are respectively the lower and upper limits of the neutron measurement range of the power range detector;

[0252] When the neutron flux density and power level measurement range under the full operating condition of the startup detector, and the neutron flux density and power level measurement range under the full operating condition of the power range detector satisfy formula (3), determine that the ranges of the startup detector and the power range detector satisfy range coverage continuity;

[0253] When the neutron flux density and power level measurement range under the full operating condition of the startup detector, and the neutron flux density and power level measurement range under the full operating condition of the power range detector do not satisfy formula (3), determine that the ranges of the startup detector and the power range detector do not satisfy range coverage continuity.

[0254] In the detector setting device of the micro-reactor in this embodiment, by adjusting the initial parameters of the neutron source and the detector, it is ensured that accurate nuclear monitoring data can still be obtained even in the complex and harsh in-reactor environment; through continuous verification and sensitivity adjustment, seamless connection of the detector range coverage is ensured, and the detector can work effectively under the condition of external reactor structure interference, avoiding the blind area problem that traditional detectors are prone to. According to the parameter adjustment under different working conditions, it is ensured that the detector can monitor the response of the micro-reactor in real time and accurately, improving the continuity and accuracy of nuclear monitoring. Even under different operating states or environmental conditions, the detector can reliably respond to neutron signals and provide stable data support.

[0255] Embodiment 4:

[0256] This embodiment provides a micro-reactor nuclear monitoring system for a micro-reactor, and the system includes:

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

[0258] A detection module, which is used to perform nuclear monitoring on the micro-reactor through the detector.

[0259] It should be clear 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, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of this application.

[0260] The functional blocks shown in the above structural block diagrams can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a functional card, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted via a data signal carried in a carrier wave on a transmission medium or a communication link. "Machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical discs, hard disks, fiber optic media, radio frequency (RF) links, and so on. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

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

[0262] As described above with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each block in the flowchart and / or block diagram, and the combination of blocks in the flowchart and / or block diagram, 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 devices to produce a machine, such that the instructions executed by the processor of the computer or other programmable scheduling devices enable the implementation of the functions / actions specified in one or more blocks of the flowchart and / or block diagram. 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 can also be understood that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can also be implemented by dedicated hardware that executes the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

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

Claims

1. A method for arranging detectors of a micro reactor, characterized in that, The method includes: Obtaining the core structure parameters and out-of-core structure parameters of the microreactor, where the core structure parameters include the initial parameters of the neutron source, and the out-of-core structure parameters include the initial parameters of the startup detector and the power range detector; Adjusting the initial parameters of the neutron source and the initial parameters of the startup detector according to the counting rate requirements of the startup detector and the fission neutron proportion threshold under different working conditions to obtain the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector; Adjusting the initial parameters of the power range detector by verifying the continuity of range coverage of the startup detector and the power range detector to obtain the second sensitivity and the third position of the power range detector; Performing detector setting on the microreactor according to the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector.

2. The method according to claim 1, wherein The adjusting the initial parameters of the neutron source and the initial parameters of the startup detector according to the counting rate requirements of the startup detector and the fission neutron proportion threshold under different working conditions to obtain the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector specifically includes: S201. Calculating the neutron flux density corresponding to each working condition according to the source strength of the neutron source and the position of the startup detector; S202. Adjusting the source strength of the neutron source and the sensitivity of the startup detector according to the neutron flux density corresponding to each working condition and the counting rate requirements of the startup detector to obtain the target source strength of the neutron source and the first sensitivity of the startup detector, Updating the initial parameters of the neutron source and the initial parameters of the startup detector according to the target source strength and the first sensitivity; S203. Calculating the first neutron flux density and the second neutron flux density according to the target source strength of the neutron source and the first sensitivity of the startup detector; Wherein, the first neutron flux density is the neutron flux density of the sensitive area of the startup detector without considering fuel fission under the third condition, the second neutron flux density is the neutron flux density of the sensitive area of the startup detector considering fuel fission under the third condition, and the third condition is the core state with full fuel loading and a core k eff ≈ 0.99; S204. In the case that the first neutron flux density and the second neutron flux density do not meet the fission neutron proportion threshold verification condition, adjusting the position of the neutron source and the position of the startup detector to obtain the corrected position of the neutron source and the corrected position of the startup detector, and updating the initial parameters of the neutron source and the initial parameters of the startup detector, Returning to execute S201 - S204 until the first neutron flux density and the second neutron flux density meet the fission neutron proportion threshold verification condition, and determining the corrected position of the neutron source as the first position of the neutron source and the corrected position of the startup detector as the second position.

3. The method according to claim 2, wherein The adjusting the source strength of the neutron source and the sensitivity of the startup detector according to the neutron flux density corresponding to each working condition and the counting rate requirements of the startup detector to obtain the target source strength of the neutron source and the first sensitivity of the startup detector specifically includes: S301. Judging whether the neutron flux density corresponding to each working condition meets the counting rate requirements of the startup detector according to formula (1): Where Q is the source strength of the neutron source, St is the sensitivity of the start-up neutron detector, and σ is the calculation uncertainty, is the neutron flux density in the sensitive area of the start-up detector per unit neutron source strength under each working condition, and N is the required counting rate of the start-up neutron detector under each working condition; S302. When the neutron flux density corresponding to each working condition does not satisfy formula (1), adjust the source strength of the neutron source and / or the sensitivity of the startup detector to obtain the corrected source strength of the neutron source and / or the corrected sensitivity of the startup detector, and update the initial parameters of the neutron source and the initial parameters of the startup detector; S303. According to the updated initial parameters of the neutron source and the initial parameters of the startup detector, calculate the neutron flux density corresponding to each working condition, and return to execute S302 - S303, until the neutron flux density corresponding to each working condition satisfies formula (1), determine the corrected source strength of the neutron source as the target source strength, and determine the corrected sensitivity of the startup detector as the first sensitivity.

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

5. The method according to claim 1, wherein The continuity verification of the range coverage of the startup detector and the power range detector is carried out, and the initial parameters of the power range detector are adjusted to obtain the second sensitivity and the third position of the power range detector. Specifically, it includes: S401. Determine the neutron flux density and the power level measurement range under the full - power operation condition of the startup detector; S402. Determine the neutron flux density and the power level measurement range under the full - power operation condition of the power range detector; S403. According to the neutron flux density and the power level measurement range under the full - power operation condition of the startup detector, and the neutron flux density and the power level measurement range under the full - power operation condition of the power range detector, judge whether the ranges of the startup detector and the power range detector satisfy the range coverage continuity; S404. When the ranges of the startup detector and the power range detector do not satisfy the range coverage continuity, adjust at least one of the sensitivity, position, power level measurement range of the power range detector, and the power level measurement range of the startup detector to obtain the corrected sensitivity, corrected position, corrected measurement range of the power range detector, and the corrected measurement range of the startup detector, and update the measurement ranges in the initial parameters of the power range detector and the initial parameters of the startup detector, return to execute S402 - S404 until the ranges of the startup detector and the power range detector satisfy 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 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 startup detector as the target measurement range of the startup detector.

6. The method according to claim 5, wherein The judgment of whether the ranges of the startup detector and the power range detector satisfy the range coverage continuity according to the neutron flux density and the power level measurement range under the full - power operation condition of the startup detector, and the neutron flux density and the power level measurement range under the full - power operation condition of the power range detector specifically includes: Determine whether the ranges of the startup detector and the power range detector satisfy the range coverage continuity through the following formula (3): where ψt is the neutron flux density in the sensitive region of the startup detector when the fuel is fully loaded and operating at full power, and ψp is the neutron flux density in the sensitive region of the power range detector when the fuel is fully loaded and operating at full power, which are the lower and upper limits of the neutron measurement range of the startup detector, respectively, and which are the lower and upper limits of the neutron measurement range of the power range detector, respectively; Under the neutron flux density and power level measurement ranges in the full-power operation condition of the startup detector, and the neutron flux density and power level measurement ranges in the full-power operation condition of the power range detector, when the formula (3) is satisfied, it is determined that the ranges of the startup detector and the power range detector satisfy the range coverage continuity; Under the neutron flux density and power level measurement ranges in the full-power operation condition of the startup detector, and the neutron flux density and power level measurement ranges in the full-power operation condition of the power range detector, when the formula (3) is not satisfied, it is determined that the ranges of the startup detector and the power range detector do not satisfy the range coverage continuity.

7. A nuclear monitoring method, characterized in that The method includes: Set detectors in the microreactor by the detector setting method of the microreactor according to any one of claims 1 to 6; Perform nuclear monitoring on the microreactor through the detectors.

8. A detector setting device for a micro reactor, characterized in that, The device includes: An acquisition module, configured to acquire the core structure parameters and out-of-core structure parameters of the microreactor, where the core structure parameters include the initial parameters of the neutron source, and the out-of-core structure parameters include the initial parameters of the startup detector and the power range detector; A first adjustment module, connected to the acquisition module, configured to adjust the initial parameters of the neutron source and the initial parameters of the startup detector according to the count rate requirement of the startup detector and the fission neutron ratio threshold under different working conditions, to obtain the target source strength and the first position of the neutron source, and the first sensitivity and the second position of the startup detector; A second adjustment module, connected to the first adjustment module, configured to adjust the initial parameters of the power range detector by verifying the continuity of the range coverage of the startup detector and the power range detector, to obtain the second sensitivity and the third position of the power range detector; A setting module, respectively connected to the first adjustment module and the second adjustment module, configured to perform detector setting on the microreactor according to the target source strength and the first position of the neutron source, the first sensitivity and the second position of the startup detector, and the second sensitivity and the third position of the power range detector.

9. The device according to claim 8, characterized in that, The first adjustment module includes: A first calculation unit, configured to execute S201, and calculate the neutron flux density corresponding to each working condition according to the source strength of the neutron source and the position of the startup detector, where the neutron flux density is the neutron flux density in the sensitive area of the startup detector under a unit neutron source strength; A first adjustment unit, connected to the first calculation unit, configured to execute S202, and adjust the source strength of the neutron source and the sensitivity of the startup detector according to the neutron flux density corresponding to each working condition and the count rate requirement of the startup detector, to obtain the target source strength of the neutron source and the first sensitivity of the startup detector, Update the initial parameters of the neutron source and the initial parameters of the startup detector according to the target source strength and the first sensitivity; A second calculation unit, connected to the first adjustment unit, configured to execute S203, calculate a first neutron flux density and a second neutron flux density according to the target source intensity of the neutron source and the first sensitivity of the start detector. Wherein, the first neutron flux density is the neutron flux density in the sensitive area of the startup detector without considering fuel fission under the third condition, the second neutron flux density is the neutron flux density in the sensitive area of the startup detector considering fuel fission under the third condition, and the third condition is the core state with full fuel loading and a core k eff ≈ 0.99; A second adjustment unit, connected to the second calculation unit, configured to execute S204, in the case where the first neutron flux density and the second neutron flux density do not meet the fission neutron ratio threshold verification condition, adjust the position of the neutron source and the position of the start detector to obtain a corrected position of the neutron source and a corrected position of the start detector, and update the initial parameters of the neutron source and the initial parameters of the start detector. Control the first calculation unit, the first adjustment unit, and the second calculation unit to execute the S201 to S204 until the first neutron flux density and the second neutron flux density meet the fission neutron ratio threshold verification condition, determine the corrected position of the neutron source as the first position of the neutron source, and determine the corrected position of the start detector as the second position.

10. A nuclear monitoring system, characterized in that, The system includes: The detector setting device of the micro reactor according to any one of claims 8 to 9, configured to set a detector in the micro reactor. A detection module, configured to perform nuclear monitoring on the micro reactor through the detector.

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