Method and system for measuring reactivity value of control rod of high-temperature gas cooled reactor

Abstract

The invention discloses a high-temperature gas cooled reactor control rod reactivity value measurement method and system, and relates to the technical field of high-temperature gas cooled reactor debugging and operation, and the method comprises the following steps: arranging measurement equipment to lift a to-be-measured control rod group to an upper limit, maintaining the reactor power stable operation, and carrying out initial data acquisition; calculating the theoretical reactivity value and neutron kinetic parameters of the control rod in a specific state, quickly inserting the control rod group to be measured to a lower limit, and recording data change; the reactivity value of the control rod is calculated, and the reactivity value obtained through calculation is corrected according to the initial power state of the reactor; and carrying out uncertainty analysis on the corrected reactivity value, and comparing a measurement result with a theoretical calculation value to optimize a measurement strategy. According to the invention, the time required for measurement can be reduced, the measurement precision is improved, the accuracy of the measurement result is enhanced, the measurement strategy is more perfect through continuous optimization, and the measurement result is more reliable.

Description

Technical Field

[0001] The invention relates to the technical field of high temperature gas-cooled reactor commissioning and operation, and in particular to a method and system for measuring the reactivity value of control rods of a high temperature gas-cooled reactor. Background Art

[0002] In the design and operation of nuclear reactors, the calibration and verification of core physics calculation models and corresponding programs are crucial links. Among them, the reactivity value of control rods is not only one of the important indicators to verify the accuracy of calculations, but also a key parameter to ensure the safe and stable operation of reactors. With the development of nuclear power technology, the requirements for accurate measurement of the reactivity value of control rods are increasing. Traditional measurement methods such as the periodic method have been widely used in various reactor types such as light water reactors, heavy water reactors, and high temperature gas-cooled reactors. The periodic method measures the reactor cycle at different rod positions and then calculates the integral value and differential value of the control rod. Although this method is relatively mature, it still has certain limitations in practical applications.

[0003] At present, high-temperature gas-cooled reactors usually use the periodic method to measure the reactivity value of control rods. This method requires dividing the control rod into several segments and measuring the reactivity value corresponding to each segment one by one, then summarizing the overall integral value, and calculating the differential value through the position difference of each segment. However, since the measurement of each segment will introduce a certain error, these errors will accumulate in the final result, resulting in a decrease in measurement accuracy. In addition, the segmented measurement of the periodic method is not only time-consuming, but also increases the operational complexity and potential safety risks, especially when the control rod position needs to be adjusted frequently, which may have an adverse effect on the continuous and safe operation of the reactor. Therefore, finding a more efficient and accurate method to replace the periodic method has become the focus of research. Summary of the invention

[0004] In view of the problems existing in the existing high temperature gas-cooled reactor control rod reactivity value measurement method, the present invention is proposed. Therefore, the problem to be solved by the present invention is how to provide a high temperature gas-cooled reactor control rod reactivity value measurement method and system.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor, which includes arranging measurement equipment to lift the control rod group to be measured to the upper limit position, maintaining the stable operation of the reactor power to perform initial data collection; calculating the theoretical reactivity value and neutron kinetic parameters of the control rods under a specific state, quickly inserting the control rod group to be measured to the lower limit position and recording data changes at the same time; calculating the reactivity value of the control rods, and correcting the calculated reactivity value according to the initial power state of the reactor; performing uncertainty analysis on the corrected reactivity value, and comparing the measurement results with the theoretical calculated values ​​to optimize the measurement strategy.

[0007] As a preferred solution of the method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor according to the present invention, the measuring equipment comprises a neutron detector, a temperature sensor and a control rod position indicator; the calculation of the theoretical reactivity value of the control rod under a specific state comprises the following steps: using an improved dynamic reactor equation to calculate the instantaneous reactivity of the control rod; applying the generalized least squares method to fit the reactivity curve to obtain the fitted dynamic reactor equation to calculate the theoretical reactivity value of the control rod.

[0008] As a preferred solution of the method for measuring the reactivity value of control rods of high-temperature gas-cooled reactors described in the present invention, the calculation of the reactivity value of control rods includes the following steps: constructing a space-independent point pile neutron dynamic equation for a thermal neutron reactor; integrating the point pile neutron dynamic equation to obtain a rod drop method integral formula derived from point pile dynamics that does not consider the power or neutron flux density distribution and non-step changes of rod drop; optimizing the rod drop method integral formula in combination with the characteristics of high-temperature gas-cooled reactor control rod drop, and determining the weight factor to correct the neutron density; considering the average generation time of prompt neutrons and the second limit value, obtaining the rod drop method integral formula that considers non-instantaneous rod drop; substituting the measured value of the power or neutron flux change law of the control rod falling into the reactor into the optimized integral formula to calculate the reactivity value of the control rod.

[0009] As a preferred solution of the method for measuring the reactivity value of control rods of high-temperature gas-cooled reactors described in the present invention, the correction includes temperature effect correction and power effect correction; the temperature effect correction includes calculating the three-dimensional temperature distribution change during the measurement process, applying the local temperature coefficient for correction, and obtaining a temperature correction term; arranging multiple temperature sensors in the reactor core to form a three-dimensional temperature measurement grid, and continuously recording the temperature of each measurement point during the control rod insertion process; calculating the temperature change of the measurement point, and calculating the local temperature reactivity coefficient at different positions and temperatures through the core physics calculation software; discretizing the core space into N grid cells, calculating the temperature correction contribution of each grid cell at each time point, integrating all grid cells, and obtaining a total temperature correction term.

[0010] As a preferred solution of the method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor described in the present invention, the power effect correction includes calculating the power distribution change during the measurement process, applying the local power coefficient for correction, and obtaining the power correction term; measuring the three-dimensional power distribution of the core, and continuously recording the power distribution to calculate the power change during the control rod insertion process; calculating the local power reactivity coefficient at different positions and power levels by the core physics calculation software, and dividing the core into N grid units; calculating the power correction contribution of each grid unit at each time point, integrating all grid units, obtaining the total power correction term, and calculating the final reactivity value by integrating various corrections, and calculating the final reactivity value, the calculation formula is:

[0011] ρ final =ρ0+ρ T +ρ P

[0012] In the formula, ρ final is the final reactivity value of the control rod, ρ T is the temperature correction term, ρ P is the power correction term.

[0013] As a preferred solution of the method for measuring the reactivity value of the control rod of the high temperature gas-cooled reactor described in the present invention, wherein: the uncertainty analysis of the corrected reactivity value includes the following steps: obtaining all sources of uncertainty, quantitatively evaluating each source of uncertainty, and determining the standard uncertainty; for each source of uncertainty, calculating the partial derivative of the final reactivity value to form a sensitivity coefficient matrix; evaluating the correlation between the sources of uncertainty, determining the correlation coefficient to construct a covariance matrix; calculating the synthetic standard uncertainty, determining the expanded uncertainty for simulation verification, generating random samples that meet the distribution characteristics for each source of uncertainty, using the random samples to repeatedly calculate the reactivity value, analyzing the distribution of the simulation results, calculating the standard deviation and comparing it with the expanded uncertainty, and the calculation formula is:

[0014]

[0015] where x i , x j is the source of uncertainty, u(x i ,x j ) is the element of the covariance matrix; calculate the relative contribution of each uncertainty source, sort the uncertainty sources according to the contribution size, and determine the uncertainty sources.

[0016] As a preferred solution of the method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor described in the present invention, the optimization measurement strategy includes: when the relative deviation δ between the measurement result and the theoretical calculation value is ≤ the first deviation limit, the measurement result is considered to be credible, the current measurement parameter settings and data acquisition frequency are maintained, and the final reactivity value measurement result is recorded as a credible result; when the relative deviation between the measurement result and the theoretical calculation value is greater than the first deviation limit, and the relative deviation is ≤ the second deviation limit, the measurement result is considered to have an error, the data acquisition frequency of the sensor is increased, the temperature effect correction model is updated using the latest temperature distribution data, the weight of the spatial effect correction factor in the final reactivity value calculation is increased, a secondary measurement is performed and a new relative deviation is calculated, if the new relative deviation is ≤5%, the optimized measurement result is considered to be credible; when the relative deviation δ between the measurement result and the theoretical calculation value is greater than 10% or the new relative deviation after optimization is greater than 5%, the measurement result is considered to be unreliable, the power effect correction model is updated using the latest power distribution data, the reactivity calculation is re-evaluated and adjusted, the control rod position measurement system is checked and calibrated, and the number of measurement points is increased for measurement, the processed data is compared and analyzed with the historical measurement results, and saved in a database.

[0017] In the second aspect, the present invention provides a control rod reactivity value measurement system for a high-temperature gas-cooled reactor, which includes: an acquisition module, which is used to arrange measurement equipment, lift the control rod group to be measured to the upper limit, maintain the stable operation of the reactor power to perform initial data acquisition, and record the data changes of quickly inserting the control rod group to be measured to the lower limit; a measurement module, which is used to calculate the control rod reactivity value, and correct the calculated reactivity value according to the initial power state of the reactor; an analysis module, which is used to perform uncertainty analysis on the corrected reactivity value, and compare the measurement results with the theoretical calculated values ​​to optimize the measurement strategy.

[0018] In a third aspect, the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the processor executes the computer program, the steps of a method for measuring the reactivity value of a high-temperature gas-cooled reactor control rod are implemented.

[0019] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, the steps of a method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor are implemented.

[0020] The beneficial effects of the present invention are to avoid the cumulative errors in the traditional segmented measurement method, reduce the time required for measurement, and at the same time improve the measurement accuracy, enhance the accuracy of the measurement results, make the measured value closer to the true reactive value, continuously improve the measurement method, make it more scientific and reasonable, and through continuous optimization make the measurement strategy more perfect and the measurement results more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 Flow chart of the method for measuring the reactivity value of control rods of high temperature gas-cooled reactors. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0026] Example 1

[0027] Reference Figure 1 , which is the first embodiment of the present invention, provides a method for measuring the reactivity value of a control rod of a high temperature gas-cooled reactor, comprising:

[0028] S1: Arrange the measuring equipment, lift the control rod group to be measured to the upper limit, maintain the stable operation of the reactor power and conduct initial data collection;

[0029] Specifically, the measuring equipment includes neutron detectors, temperature sensors and control rod position indicators; the test data measurement points are selected, and the nuclear measurement system of the high temperature gas-cooled reactor is arranged outside the reactor, which is divided into source range, intermediate range and power range. The source range uses a boron counter, which has high sensitivity and a lower detection range limit, but has an upper limit; the intermediate range uses a fission chamber, which has high sensitivity and a wide detection range; the power range uses a fission chamber, which has high sensitivity at higher powers and a higher detection limit. In order to avoid errors caused by fluctuations and background when measuring power or neutron flux density data and to ensure sufficient sensitivity during detection, the advantages and disadvantages of each range of the nuclear measurement system are analyzed, and the intermediate range detector is selected as the test data measurement point.

[0030] Collect test data, raise the control rod to be measured to the upper limit, raise the reactor power to a certain power level and run it stably for a period of time, and quickly drop the control rod to be measured into the reactor by gravity. When the reactor power or neutron flux density drops to 0, copy the output data of the intermediate range detector during the test through the DCS engineer station.

[0031] S2: Calculate the theoretical reactivity value and neutron kinetic parameters of the control rods under a specific state, quickly insert the control rod group to be measured to the lower limit and record the data changes;

[0032] Specifically, the calculated values ​​and neutron dynamic parameters of the control rods under specific conditions are calculated by the core physics calculation software, and the measured control rods (single or multiple) are raised to the upper limit.

[0033] The transient reactivity of the control rod is calculated using the modified dynamic reactor equation, which is expressed as:

[0034]

[0035] Where ρ(t) is the instantaneous reactivity of the control rod, Λ is the neutron lifetime, β eff is the effective delayed neutron fraction, λ is the prompt neutron decay constant, i and C i (t) are the decay constant and concentration of the delayed neutron precursor nuclei of the i-th group;

[0036] The generalized least squares method is used to fit the reactivity curve, and the fitted dynamic reactor equation is obtained, which is expressed as follows:

[0037]

[0038] Among them, ρ fit (t) is the theoretical reactivity value of the control rod, τ eff is the effective time constant, A i and τ i is the fitting parameter.

[0039] S3: Calculate the control rod reactivity value and correct the calculated reactivity value according to the initial power state of the reactor;

[0040] By integrating and solving the point pile neutron dynamic equation and approximately obtaining the reactivity-introduced falling rod method integral formula; solving the falling rod method integral formula, for thermal neutron reactors, the point pile neutron dynamic equation that is independent of space is constructed as follows:

[0041]

[0042]

[0043]

[0044] Where N(t) is the time-dependent neutron density; ρ(t) is the reactivity; β eff is the effective delayed neutron fraction; Λ is the average generation time of prompt neutrons; λ i is the delayed neutron decay constant of the i-th group; β i,eff is the effective fraction of delayed neutrons in group i; C i (t) is the density of the precursor nuclei of the i-th group; S(t) is the external neutron source.

[0045] By integrating the point-pile neutron dynamic equation, the integral formula of the dropping rod method derived from the point-pile dynamics without considering the power or neutron flux density distribution and the non-step change of the dropping rod is obtained. The expression is:

[0046]

[0047] The integral formula is corrected in combination with the characteristics of the control rod drop of the high temperature gas-cooled reactor. Considering the correction of the control rod drop time, the full stroke of the control rod of the high temperature gas-cooled reactor is greater than 11m, and the influence of the control rod drop time on the power or neutron flux density needs to be considered.

[0048] The power or neutron flux density is multiplied by the weight factor in different time periods for correction, and the wide pulse weight function with better effect is selected for optimization. The weight function is as follows:

[0049]

[0050] Where W(t) is the weight factor, t1 is the first limit, which is the time when the control rod falls to the lower limit, and t2 is the second limit, which is the time when the power or neutron flux density drops by more than 3 orders of magnitude.

[0051] Considering the average generation time of prompt neutrons and the second limit, the integral formula of the falling rod method considering the non-instantaneous falling rod is finally obtained, which is expressed as:

[0052]

[0053] The value of the control rod is calculated by substituting the measured law of power or neutron flux change when the control rod falls into the reactor into the optimized integral formula.

[0054] The correction includes temperature effect correction and power effect correction; the temperature effect correction includes calculating the change of three-dimensional temperature distribution during the measurement process, applying the local temperature coefficient for correction, and obtaining the temperature correction term;

[0055] Multiple temperature sensors are arranged in the reactor core to form a three-dimensional temperature measurement grid, and the temperature of each measurement point is continuously recorded during the control rod insertion process;

[0056] Calculate the temperature change at the measuring point and calculate the local temperature reactivity coefficient at different positions and temperatures using the core physics calculation software;

[0057] The core space is discretized into N grid cells, the temperature correction contribution of each grid cell is calculated at each time point, and the total temperature correction term is obtained by integrating all grid cells.

[0058] The power effect correction includes calculating the power distribution change during the measurement process, applying the local power coefficient for correction, and obtaining the power correction term;

[0059] Measure the three-dimensional power distribution in the core and continuously record the power distribution and calculate the power change during the control rod insertion process;

[0060] The core is divided into N grid cells by calculating the local power reactivity coefficients at different positions and power levels using core physics calculation software;

[0061] Calculate the power correction contribution of each grid unit at each time point, integrate all grid units to get the total power correction term, and calculate the final reactivity value by combining various corrections. The calculation formula is:

[0062] ρ final =ρ0+ρ T +ρ P

[0063] In the formula, ρ final is the final reactivity value of the control rod, ρ T is the temperature correction term, ρ P is the power correction term.

[0064] S4: Perform uncertainty analysis on the corrected reactivity value and compare the measurement results with the theoretical calculated values ​​to optimize the measurement strategy.

[0065] Obtain all sources of uncertainty, quantitatively evaluate each source of uncertainty, and determine the standard uncertainty;

[0066] The sources of uncertainty include neutron flux measurement error, control rod position measurement error, temperature measurement error, power measurement error, reactivity calculation method error, temperature coefficient uncertainty, power coefficient uncertainty and space effect correction factor uncertainty;

[0067] For each uncertainty source, the partial derivatives with respect to the final reactivity value are calculated to form a sensitivity coefficient matrix;

[0068] Evaluate the correlation between the uncertainty sources, determine the correlation coefficients and construct the covariance matrix;

[0069] Calculate the combined standard uncertainty, determine the expanded uncertainty for simulation verification, generate random samples that meet the distribution characteristics for each uncertainty source, use random samples to repeatedly calculate the reactivity value, analyze the distribution of simulation results, calculate the standard deviation and compare it with the expanded uncertainty. The calculation formula is:

[0070]

[0071] where x i , x j is the source of uncertainty, u(x i ,x j ) is the covariance matrix element;

[0072] Calculate the relative contribution of each uncertainty source, sort the uncertainty sources according to their contribution, and determine the uncertainty sources.

[0073] When the relative deviation δ between the measurement result and the theoretical calculated value is ≤ the first limit of the deviation, the measurement result is considered to be credible, the current measurement parameter settings and data acquisition frequency are maintained, and the final reactive value measurement result is recorded as a credible result;

[0074] When the first limit of the relative deviation between the measurement result and the theoretical calculated value is less than δ ≤ the second limit of the deviation, it is considered that there is an error in the measurement result, the data acquisition frequency of the sensor is increased, the temperature effect correction model is updated using the latest temperature distribution data, the weight of the spatial effect correction factor in the calculation of the final reactivity value is increased, a second measurement is performed and a new relative deviation is calculated. If the new relative deviation is ≤5%, the optimized measurement result is considered to be credible;

[0075] When the relative deviation δ between the measurement result and the theoretical calculated value is greater than 10% or the new relative deviation after optimization is greater than 5%, the measurement result is considered unreliable, the power effect correction model is updated using the latest power distribution data, the reactivity calculation is re-evaluated and adjusted, the control rod position measurement system is checked and calibrated, and the number of measurement points is increased for measurement, the processed data is compared and analyzed with the historical measurement results, and saved in the database. The first limit of deviation is 5%, and the second limit of deviation is 10%.

[0076] Furthermore, the present embodiment also provides a control rod reactivity value measurement system for a high-temperature gas-cooled reactor, comprising: an acquisition module, used to arrange measurement equipment, lift the control rod group to be measured to the upper limit, maintain stable reactor power operation for initial data acquisition, and record data changes when the control rod group to be measured is quickly inserted to the lower limit; a measurement module, used to calculate the control rod reactivity value, and correct the calculated reactivity value according to the initial power state of the reactor; an analysis module, used to perform uncertainty analysis on the corrected reactivity value, and compare the measurement results with the theoretical calculated values ​​to optimize the measurement strategy.

[0077] This embodiment also provides a computer device, which is applicable to the case of a method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor, and includes: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement all or part of the steps of the method described in the embodiment of the present invention as proposed in the above embodiment.

[0078] This embodiment also provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method in any optional implementation of the above embodiment is executed. Wherein, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, disk or optical disk.

[0079] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0080] From the above, it can be seen that this method can greatly shorten the test time by measuring the value of an entire control rod or a group of control rods at a time and processing the test data offline. Quickly measure the integral value of a control rod or multiple controls. By selecting the mid-range detection as the data measurement point, the initial power of the reactor test can be increased, errors caused by fluctuations and background during data measurement can be avoided, and the test measurement accuracy can be improved. Avoid the cumulative errors in the traditional segmented measurement method, reduce the time required for measurement, and at the same time improve the measurement accuracy, enhance the accuracy of the measurement results, make the measured value closer to the true reactivity value, continuously improve the measurement method, make it more scientific and reasonable, and make the measurement strategy more perfect and the measurement results more reliable through continuous optimization.

[0081] Example 2

[0082] Referring to Table 1, which is the second embodiment of the present invention, this embodiment provides a method for measuring the reactivity value of control rods of a high-temperature gas-cooled reactor. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments. Taking the measurement of the reactivity value of two control rods as an example, this method adopts simulation experiments, and the periodic method adopts actual test data for comparison.

[0083] Table 1 Test data table

[0084]

[0085] As can be seen from the above, the average measurement time of this method is 2.3 hours, while the average measurement time of the periodic method is 15.3 hours. This shows that the method of the present invention greatly shortens the measurement time and improves work efficiency. Compared with the traditional method, it reduces the time required for measurement, enhances the accuracy of the measurement results, is more scientific and reasonable, and the measurement results are more reliable.

[0086] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor, characterized in that: include, Arrange the measuring equipment, lift the control rod group to be measured to the upper limit, maintain the stable operation of the reactor power and conduct initial data collection; Calculate the theoretical reactivity value and neutron kinetic parameters of the control rods under specific conditions, quickly insert the control rod group to be measured to the lower limit and record the data changes; Calculate the control rod reactivity value and correct the calculated reactivity value according to the initial power state of the reactor; Uncertainty analysis was performed on the corrected reactivity values, and the measurement results were compared with the theoretical calculated values ​​to optimize the measurement strategy.

2. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 1, characterized in that: The measuring equipment includes neutron detectors, temperature sensors and control rod position indicators; The calculation of the theoretical reactivity value of the control rod under a specific state comprises the following steps: Calculate the transient reactivity of control rods using the modified dynamic reactor equations; The generalized least square method is used to fit the reactivity curve, and the fitted dynamic reactor equation is obtained to calculate the theoretical reactivity value of the control rod.

3. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 2, characterized in that: The calculation of the control rod reactivity value comprises the following steps, Constructing the space-independent point-pile neutron dynamic equations for thermal neutron reactors; By integrating the point-pile neutron dynamic equation, the integral formula of the dropping-rod method derived from the point-pile dynamics is obtained without considering the power or neutron flux density distribution and the non-step change of the dropping rod. The integral formula of the control rod drop method is optimized based on the characteristics of the high temperature gas-cooled reactor control rod drop, and the weight factor is determined to correct the neutron density. Considering the average generation time of prompt neutrons and the second limit, the integral formula of the falling-rod method considering the non-instantaneous falling-rod is obtained; The measured value of the power or neutron flux variation law when the control rod falls into the reactor is substituted into the optimized integral formula to calculate the reactivity value of the control rod.

4. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 3, characterized in that: The correction includes temperature effect correction and power effect correction; The temperature effect correction includes calculating the change of three-dimensional temperature distribution during the measurement process, applying the local temperature coefficient for correction, and obtaining the temperature correction term; Multiple temperature sensors are arranged in the reactor core to form a three-dimensional temperature measurement grid, and the temperature of each measurement point is continuously recorded during the control rod insertion process; Calculate the temperature change at the measuring point and calculate the local temperature reactivity coefficient at different positions and temperatures using the core physics calculation software; The core space is discretized into N grid cells, the temperature correction contribution of each grid cell is calculated at each time point, and the total temperature correction term is obtained by integrating all grid cells.

5. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 4, characterized in that: The power effect correction includes calculating the power distribution change during the measurement process, applying the local power coefficient for correction, and obtaining a power correction term; Measure the three-dimensional power distribution in the core and continuously record the power distribution and calculate the power change during the control rod insertion process; The core is divided into N grid cells by calculating the local power reactivity coefficients at different positions and power levels using core physics calculation software; Calculate the power correction contribution of each grid unit at each time point, integrate all grid units to get the total power correction term, and calculate the final reactivity value by combining various corrections. The calculation formula is: r final =ρ0+ρ T +r P In the formula, ρ final is the final reactivity value of the control rod, ρ T is the temperature correction term, ρ P is the power correction term.

6. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 5, characterized in that: The uncertainty analysis of the modified reactivity value comprises the following steps: Obtain all sources of uncertainty, quantitatively evaluate each source of uncertainty, and determine the standard uncertainty; For each uncertainty source, the partial derivatives with respect to the final reactivity value are calculated to form a sensitivity coefficient matrix; Evaluate the correlation between the uncertainty sources, determine the correlation coefficients and construct the covariance matrix; Calculate the combined standard uncertainty, determine the expanded uncertainty for simulation verification, generate random samples that meet the distribution characteristics for each uncertainty source, use random samples to repeatedly calculate the reactivity value, analyze the distribution of simulation results, calculate the standard deviation and compare it with the expanded uncertainty. The calculation formula is: where x i , x j is the source of uncertainty, u(x i ,x j ) is the covariance matrix element; Calculate the relative contribution of each uncertainty source, sort the uncertainty sources according to their contribution, and determine the uncertainty sources.

7. The method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to claim 6, characterized in that: The optimization measurement strategy includes: when the relative deviation δ between the measurement result and the theoretical calculated value is less than or equal to the first deviation limit, the measurement result is considered to be credible, the current measurement parameter settings and data acquisition frequency are maintained, and the final reactive value measurement result is recorded as a credible result; When the relative deviation between the measurement result and the theoretical calculation value is greater than the first limit of the deviation, and the relative deviation is less than or equal to the second limit of the deviation, it is considered that the measurement result has an error, the data acquisition frequency of the sensor is increased, the temperature effect correction model is updated using the latest temperature distribution data, the weight of the spatial effect correction factor in the calculation of the final reactivity value is increased, a second measurement is performed and a new relative deviation is calculated. If the new relative deviation is less than or equal to 5%, the optimized measurement result is considered to be credible; When the relative deviation δ between the measurement result and the theoretical calculated value is greater than 10% or the new relative deviation after optimization is greater than 5%, the measurement result is considered unreliable, the power effect correction model is updated using the latest power distribution data, the reactivity calculation is re-evaluated and adjusted, the control rod position measurement system is checked and calibrated, and the number of measurement points is increased for measurement. The processed data is compared and analyzed with the historical measurement results and saved in the database.

8. A high temperature gas-cooled reactor control rod reactivity value measurement system, based on the high temperature gas-cooled reactor control rod reactivity value measurement method according to any one of claims 1 to 7, characterized in that: include, The acquisition module is used to arrange the measuring equipment, lift the control rod group to be measured to the upper limit, maintain the stable operation of the reactor power for initial data acquisition, and record the data changes of the control rod group to be measured when it is quickly inserted to the lower limit; A measurement module, used for calculating the control rod reactivity value and correcting the calculated reactivity value according to the initial power state of the reactor; The analysis module is used to perform uncertainty analysis on the corrected reactivity value and compare the measurement results with the theoretical calculated values ​​to optimize the measurement strategy.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for measuring the reactivity value of control rods of a high temperature gas-cooled reactor described in any one of claims 1 to 7 are implemented.

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