Analog calculation method and system suitable for telescopic control rod of pebble-bed high-temperature gas cooled reactor

Abstract

The invention discloses a simulation calculation method and system suitable for a telescopic control rod of a pebble-bed high-temperature gas cooled reactor, and relates to the field of nuclear reactor physical and thermal calculation, and the simulation calculation method comprises the following steps: collecting data information of each part of the telescopic control rod, and determining the grid division size of a reactor core model and the insertion depth of the control rod in the current state; establishing all axial grids of the control rod channel, and calculating the neutron-flux density of each part in the axial grids according to the neutron-flux density and size of the adjacent axial grids; uniformization calculation and neutron current effect correction are completed, and uniformization sections of all axial grids of the control rod channel are obtained. Under the condition of fixed grid division, aiming at various different sleeve type control rod combinations appearing in the grid, the flux and the length of each combination in the grid are used as weights to complete control rod grid homogenization calculation, an accurate homogenization cross section can be provided for subsequent reactor core physical calculation, and the calculation precision of a control rod problem is improved.

Description

Technical Field

[0001] The present invention relates to the field of nuclear reactor physics calculation, and in particular to a simulation calculation method and system suitable for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor. Background Art

[0002] Reactivity control is crucial to the safe operation of the reactor. Current pebble bed modular high-temperature gas-cooled reactor nuclear power plants generally use two reactivity control and shutdown systems, namely the control rod system and the absorber ball shutdown system. During the operation of the reactor, the position of the control rods needs to be moved to adjust the reactivity of the reactor to meet the requirements of safe operation.

[0003] Before a reactor is put into operation, a reactivity plan must be developed, which involves simulation calculations of control rods in nuclear reactor physics. The control rods of a pebble bed modular high-temperature gas-cooled reactor nuclear power plant use an inner and outer control rod sleeve structure, and the outer control rod has a downward insertion limit. Therefore, in actual operation, the outer control rod will remain in position while the inner control rod continues to be inserted, at which point the inner and outer control rods will separate. If a reflective layer with a certain height containing control rod holes is taken in the axial direction, the control rods inside will have three combinations:

[0004] 1) Contains only inner control rods;

[0005] 2) Contains only outer control rods;

[0006] 3) Inner and outer control rods exist at the same time.

[0007] Furthermore, during core simulations of high-temperature gas-cooled reactors, the position of control rods shifts as the simulated operating conditions change. This makes it easy for control rods to be partially inserted into the pre-defined model grid. Furthermore, due to the control rods' telescopic structure, multiple control rod combinations can occur within the grid, making it difficult to achieve uniform grid alignment. Therefore, it was necessary to develop a simulation method for telescopic control rods in pebble-bed high-temperature gas-cooled reactors, tailored to the telescopic control rod structure and the operational characteristics of this reactor type. Summary of the Invention

[0008] In view of the above-mentioned problems, the present invention is proposed.

[0009] Therefore, the technical problem solved by the present invention is: to be able to complete the homogenization calculation of the control rod channel grid in the complex situation where the separation of the sleeve-type control rod structure leads to multiple control rod combinations in the grid, provide an accurate homogenization cross-section for subsequent core calculations, and thus improve the calculation accuracy.

[0010] To solve the above technical problems, the present invention provides the following technical solution: a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor, comprising the following steps:

[0011] Collect data on various parts of the sleeve-type control rods to determine the mesh size of the reactor core model and the control rod insertion depth in the current state;

[0012] Establish all axial grids of the control rod channel and obtain the control rod combinations and corresponding lengths within each grid;

[0013] Calculate the neutron flux density of each part of all axial grids of the control rod channel based on the neutron flux density and size of adjacent axial grids;

[0014] According to the neutron flux density and axial length of each part in the grid, the homogenization calculation and neutron flow effect correction are completed to obtain the homogenized cross-section of all axial grids in the control rod channel.

[0015] As a preferred solution of the simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor described in the present invention, the data information of each part of the sleeve-type control rod is collected to confirm the lengths of the inner and outer rods of the sleeve-type control rods used in the pebble bed high-temperature gas-cooled reactor, as well as the moving length range of the inner and outer rods, to obtain the grid division size of the reactor core model and the control rod insertion depth in the current state.

[0016] As a preferred embodiment of the simulation calculation method for sleeve-type control rods of a pebble-bed high-temperature gas-cooled reactor according to the present invention, the method of establishing all axial grids of the control rod channel and obtaining the control rod combinations and corresponding lengths within each grid is based on the insertion depth of the control rods and the positions of the upper and lower edges of the inner and outer rods, as expressed by:

[0017]

[0018] p in,↓ =d 0≤d≤s total

[0019]

[0020] Among them, p in,↑ 、p in,↓ is the upper and lower edge positions of the inner rod, p out,↑ 、p out,↓ is the upper and lower edge positions of the outer rod, s total is the maximum insertion depth of the control rod, s out is the maximum insertion depth of the outer rod; l in is the inner rod length of the telescopic control rod, l out is the outer rod length of the cylindrical control rod, and d is the control rod insertion depth in the current state;

[0021] Based on all axial grids of the control rod channel, the boundary position or coordinates of each grid in the axial direction are obtained. Combined with the obtained upper and lower edge positions of each part of the sleeve-type control rod, the control rod combinations within all grids and the corresponding lengths of each control rod combination are traversed to obtain.

[0022] As a preferred embodiment of the simulation calculation method for sleeve-type control rods of a pebble-bed high-temperature gas-cooled reactor according to the present invention, the calculation of the neutron flux density of each portion within all axial grids of the control rod channel includes solving the neutron diffusion equation to obtain the neutron flux density on all grids of the reactor core model, which is expressed as follows:

[0023] -D g (u)▽ 2 φ g (u)+Σ r,g (u)φ g (u) = Q g (u)

[0024]

[0025] Among them, u is the spatial position variable, g is the energy group variable; G is the total number of energy groups; ▽ 2 is the Laplace operator; φ g is the neutron flux density of the gth group; Q g The source term for the g-th group neutrons; D g is the diffusion coefficient of the gth group; ν is the average number of neutrons produced per fission; Σ f,g is the macroscopic fission reaction cross section of group g, f represents fission; χ g is the fission energy spectrum of the gth group; Σ s,g→g′ is the macroscopic scattering cross section from the gth group to the g′th group, s represents scattering; k eff is the effective proliferation coefficient; Σ r,g is the macroscopic removal cross section of the gth group, that is, the macroscopic total cross section minus the macroscopic self-scattering cross section, and r represents the removal.

[0026] As a preferred embodiment of the simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to the present invention, the calculation of the neutron flux density of each part within all axial grids of the control rod channel further includes:

[0027] According to the neutron flux density of adjacent axial grids and the grid size in the axial direction, the neutron flux density of each part of all axial grids in the control rod channel is calculated as follows:

[0028]

[0029] Where z is the axial grid number, grid z+1 is located above grid z; g is the energy group number;

[0030] is the neutron flux density of the gth group in the upper half of the grid z; is the neutron flux density of the gth group in the lower half of the grid z; φ z+1,g 、φ z,g 、φ z-1,g is the neutron flux density of the gth group in grids z+1, z and z-1; h z+1 、h z-1 is the axial length of grids z+1 and z-1; is the axial length of the upper half of the grid z; is the axial length of the lower half of the grid z;

[0031] The grid size in the axial direction includes the axial length.

[0032] As a preferred embodiment of the simulation calculation method for sleeve-type control rods of a pebble-bed high-temperature gas-cooled reactor according to the present invention, the homogenization calculation and neutron flux effect correction are performed based on the neutron flux density and axial length of each portion within the grid to obtain the homogenized cross-section of all axial grids of the control rod channel. The homogenization calculation and neutron flux effect correction are performed based on the neutron flux density and axial length of each portion within the grid, with the product of flux and length as the weight, to obtain the homogenized cross-section of the axial grid of the control rod channel. The expression is:

[0033]

[0034] Among them, x represents the type of nuclear reaction; Σ x,z,g is the homogenized cross section of the gth group of grid z; is the gth group homogenized section of the upper half of the grid z; is the gth group homogenized section of the lower half of the grid z;

[0035] The nuclear reaction types include total reaction, absorption reaction and scattering reaction.

[0036] Another object of the present invention is to provide a simulation calculation system for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor. The system can perform control rod grid homogenization calculations for a variety of different sleeve-type control rod combinations appearing in the grid, using the flux and length of each combination in the grid as weights, thereby solving the problem that existing methods are difficult to perform homogenization calculations for the situation where a variety of control rod combinations appear in the control rod grid.

[0037] To solve the above technical problems, the present invention provides the following technical solutions: a simulation and calculation system for sleeve-type control rods of a pebble-bed high-temperature gas-cooled reactor, comprising: a data acquisition and preprocessing module, a grid generation and establishment module, a neutron flux solution module, and a homogenization calculation and neutron flux correction module;

[0038] The data acquisition and preprocessing module collects and processes input data related to the sleeve-type control rods and the reactor core, confirms the structural parameters of the pebble-bed high-temperature gas-cooled reactor, and determines the mesh size of the reactor core model and the control rod insertion depth;

[0039] The grid generation and establishment module generates an axial grid of the control rod channel and establishes the boundary position and coordinates of the grid;

[0040] The neutron flux solving module solves the neutron flux density on all grids in the reactor core based on the neutron diffusion equation, and calculates the neutron flux density of each part in each axial grid of the control rod channel according to the neutron flux density of the adjacent axial grids of the control rod channel;

[0041] The homogenization calculation and neutron flux correction module performs homogenization calculation based on the neutron flux density and axial length of each part in the grid, obtains the homogenized cross section of each grid through neutron flux effect correction, and completes the correction using the weighted average method.

[0042] A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the steps of the above-mentioned simulation calculation method applicable to sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor.

[0043] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor.

[0044] The beneficial effects of the present invention are as follows: under the condition of fixed grid division, the control rod grid homogenization calculation can be completed for a variety of different sleeve-type control rod combinations appearing in the grid, using the flux and length of each combination in the grid as weights, thereby providing an accurate homogenization cross section for subsequent core physics calculations and improving the calculation accuracy of control rod problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] 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 paying any creative work.

[0046] Figure 1 This is an overall flow chart of a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor, provided in accordance with the first embodiment of the present invention;

[0047] Figure 2 This is a graph showing the calculation results of the reactivity value curve of HTR-PM6 regulating rods in a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0048] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only 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 this field without creative work should fall within the scope of protection of the present invention.

[0049] Example 1, with reference to Figure 1 As one embodiment of the present invention, a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor is provided, comprising:

[0050] First, the lengths of the inner and outer rods of the sleeve-type control rods used in the pebble bed modular high-temperature gas-cooled reactor, as well as the range of their movable lengths, are determined to obtain the grid division size of the reactor core model and the control rod insertion depth in the current state. Then, the positions of the upper and lower edges of the inner and outer rods are determined, and all axial grids of the control rod channel are established to obtain the control rod combination and corresponding length within each grid. Based on the neutron flux density and size of adjacent axial grids, the neutron flux density of each part within all axial grids of the control rod channel is calculated. Finally, based on the neutron flux density and axial length of each part within the grid, homogenization calculations and neutron flow effect corrections are completed to obtain the homogenized cross-sections of all axial grids of the control rod channel for subsequent core calculations.

[0051] The following describes the calculation process of the homogenized neutron diffusion coefficient of the reflector layer containing control rods, taking the reflector layer containing inner and outer control rods as an example. The specific steps include:

[0052] Step 1: Confirm the length of the inner and outer rods of the sleeve-type control rods used in the pebble bed high-temperature gas-cooled reactor (l in and l out ), as well as the moving length ranges of the inner and outer rods, to obtain the mesh size of the reactor core model and the control rod insertion depth d in the current state;

[0053] Step 2: To obtain the control rod combination inside the control rod channel grid of the reactor model, confirm the upper and lower edge positions of the inner and outer rods based on the control rod insertion depths obtained in Step 1:

[0054]

[0055] pin,↓ =d 0≤d≤s total (2)

[0056]

[0057] Among them, p in,↑ 、p in,↓ is the upper and lower edge positions of the inner rod, p out,↑ 、p out,↓ is the upper and lower edge positions of the outer rod, s total is the maximum insertion depth of the control rod, s out is the maximum insertion depth of the outer rod; l in is the inner rod length of the telescopic control rod, l out is the outer rod length of the cylindrical control rod, and d is the control rod insertion depth in the current state.

[0058] Then, all axial grids of the control rod channel are established, and according to the boundary positions or coordinates of the control rod channel grids in the axial direction, the control rod combinations and corresponding lengths within all grids are obtained;

[0059] Step 3: Since the neutron flux density of different control rod combinations within the control rod grid is inconsistent, and the control rod grid considers the differences in neutron flux density of each combination within the grid during the homogenization calculation process, it is necessary to solve the neutron flux density of each combination within the grid. To this end, the present invention first solves the neutron diffusion equation to obtain the neutron flux density on all grids of the reactor core model. The equation is expressed as:

[0060] -D g (u)▽ 2 φ g (u)+Σ r,g (u)φ g (u) = Q g (u) (5)

[0061]

[0062] Among them, u is the spatial position variable, g is the energy group variable; G is the total number of energy groups; ▽ 2 is the Laplace operator; φ g is the neutron flux density of the gth group; Q g The source term for the g-th group neutrons; D g is the diffusion coefficient of the gth group; ν is the average number of neutrons produced per fission; Σ f,g is the macroscopic fission reaction cross section of group g, f represents fission; χ g is the fission energy spectrum of the gth group; Σ s,g→g′ is the macroscopic scattering cross section from the gth group to the g′th group, s represents scattering; k effis the effective proliferation coefficient; Σ r,g is the macroscopic removal cross section of the gth group, that is, the macroscopic total cross section minus the macroscopic self-scattering cross section, and r represents the removal.

[0063] Then, the neutron flux density of each part of all axial grids in the control rod channel is calculated based on the neutron flux density of adjacent axial grids and the grid size in the axial direction. The expression is:

[0064]

[0065] Where z is the axial grid number, grid z+1 is located above grid z; g is the energy group number; is the neutron flux density of the gth group in the upper half of the grid z; is the neutron flux density of the gth group in the lower half of the grid z; φ z+1,g 、φ z,g 、φ z-1,g is the neutron flux density of the gth group in grids z+1, z and z-1; h z+1 、h z-1 is the axial length of grids z+1 and z-1; is the axial length of the upper half of the grid z; is the axial length of the lower half of the grid z;

[0066] It should be further explained that:

[0067] The mesh size in the axial direction includes the axial length.

[0068] This step of the present invention utilizes the neutron flux density of adjacent axial grids and the grid size in the axial direction to approximately calculate the neutron flux density of each control rod combination within the control rod channel grid, omitting the neutron diffusion calculation of the local control rod half-insertion grid, thereby reducing the amount of calculation and ensuring the efficiency of the reactor simulation calculation.

[0069] Step 4: Based on the neutron flux density and axial length of each part of the grid obtained in Steps 2 and 3, the product of flux and length is used as the weight to complete the homogenization calculation and neutron flux effect correction to obtain the homogenized cross-section of all axial grids in the control rod channel:

[0070]

[0071] Among them, x represents the type of nuclear reaction; Σ x,z,g is the homogenized cross section of the gth group of grid z; is the gth group homogenized section of the upper half of the grid z; is the gth group homogenized cross section in the lower half of the grid z; nuclear reaction types include total reaction, absorption reaction and scattering reaction.

[0072] This step of the present invention takes into account the neutron flux density differences of each control rod combination within the grid control rod channel grid, performs homogenization calculations and neutron flow effect corrections on the control rod channel grid, and obtains a high-precision homogenization cross section, providing reliable data for subsequent precise calculations of the core.

[0073] Example 2 is an embodiment of the present invention, which provides a system for a simulation calculation method of sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor, including: a data acquisition and preprocessing module, a grid generation and establishment module, a neutron flux solution module, and a homogenization calculation and neutron flux correction module.

[0074] The data acquisition and preprocessing module collects and processes input data related to the sleeve-type control rods and the reactor core, confirms the structural parameters of the pebble-bed high-temperature gas-cooled reactor, and determines the grid size of the reactor core model and the control rod insertion depth.

[0075] The grid generation and establishment module generates the axial grid of the control rod channel and establishes the boundary position and coordinates of the grid.

[0076] The neutron flux solving module solves the neutron flux density on all grids in the reactor core based on the neutron diffusion equation, and calculates the neutron flux density of each part within each axial grid of the control rod channel according to the neutron flux density of the adjacent axial grids of the control rod channel.

[0077] The homogenization calculation and neutron flux correction module performs homogenization calculation based on the neutron flux density and axial length of each part in the grid, obtains the homogenized cross section of each grid through neutron flux effect correction, and completes the correction using the weighted average method.

[0078] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0079] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0080] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0081] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0082] Example 3: In this example, in order to verify the beneficial effects of the present invention, economic benefit calculation and simulation experiments were conducted to scientifically demonstrate the effectiveness of the present invention. This example conducted experiments on the existing traditional method and the method of this example.

[0083] In order to verify the feasibility and effectiveness of the method of the present invention, a core model of a high-temperature gas-cooled reactor nuclear power plant demonstration project (HTR-PM) was used for calculation verification. The bottom of the pebble bed of the model is filled with 605cm of graphite balls, and the top is loaded with 385cm of fuel balls and graphite balls. The number ratio of the two balls is 7:8, the enrichment of uranium dioxide is 4.2%, the pebble bed filling rate is 61%, and the helium atmosphere in the reactor is 600K. The high-temperature gas-cooled reactor core physics calculation program NECP-Panda was used to calculate the reactivity value of the six regulating rods in the model. The continuous energy calculation results of the Monte Carlo particle transport calculation software NECP-MCX were used as the reference solution. Table 1 shows the calculation results of the reactivity value of the six regulating rods. Figure 2 The reactivity value curves of 6 adjustment rods are given.

[0084] Table 1 Calculation results of the reactivity value of 6 regulating rods

[0085]

[0086] As can be seen from Table 1, the control rod reactivity value calculated based on the method of the present invention for the pebble bed high-temperature gas-cooled reactor is only 3.93% larger than the Monte Carlo reference solution. The keff calculation deviations corresponding to the fully inserted and fully withdrawn control rod states are both within 200 pcm, demonstrating that the method of the present invention is completely feasible and accurate for the simulation calculation of sleeve-type control rods in the pebble bed high-temperature gas-cooled reactor.

[0087] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. 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 simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor, characterized in that: include: Collect data on various parts of the sleeve-type control rods to determine the mesh size of the reactor core model and the control rod insertion depth in the current state; Establish all axial grids of the control rod channel and obtain the control rod combinations and corresponding lengths within each grid; Calculate the neutron flux density of each part of all axial grids of the control rod channel based on the neutron flux density and size of adjacent axial grids; According to the neutron flux density and axial length of each part in the grid, the homogenization calculation and neutron flow effect correction are completed to obtain the homogenized cross-section of all axial grids in the control rod channel.

2. The simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to claim 1, characterized in that: The purpose of collecting data information on various parts of the sleeve-type control rods is to confirm the lengths of the inner and outer rods of the sleeve-type control rods used in the pebble bed high-temperature gas-cooled reactor, as well as the range of their movable lengths, and to obtain the mesh size of the reactor core model and the control rod insertion depth in the current state.

3. The simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to claim 2, characterized in that: The establishment of all axial grids of the control rod channel and the determination of the control rod combination and corresponding length within each grid are based on the insertion depth of the control rods and the determination of the upper and lower edge positions of the inner and outer rods. The expression is: p in,↓ =d 0≤d≤s total Among them, p in,↑ 、p in,↓ is the upper and lower edge positions of the inner rod, p out,↑ 、p out,↓ is the upper and lower edge positions of the outer rod, s total is the maximum insertion depth of the control rod, s out is the maximum insertion depth of the outer rod; l in is the inner rod length of the telescopic control rod, l out is the outer rod length of the cylindrical control rod, and d is the control rod insertion depth in the current state; Based on all axial grids of the control rod channel, the boundary position or coordinates of each grid in the axial direction are obtained. Combined with the obtained upper and lower edge positions of each part of the sleeve-type control rod, the control rod combinations within all grids and the corresponding lengths of each control rod combination are traversed to obtain.

4. The simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to claim 3, characterized in that: The calculation of the neutron flux density of each part of all axial grids of the control rod channel includes solving the neutron diffusion equation to obtain the neutron flux density on all grids of the reactor core model, which is expressed as: Among them, u is the spatial position variable, g is the energy group variable; G is the total number of energy groups; is the Laplace operator; φ g is the neutron flux density of the gth group; Q g The source term for the g-th group neutrons; D g is the diffusion coefficient of the gth group; ν is the average number of neutrons produced per fission; Σ f,g is the macroscopic fission reaction cross section of group g, f represents fission; χ g is the fission energy spectrum of the gth group; Σ s,g→g′ is the macroscopic scattering cross section from the gth group to the g′th group, s represents scattering; keff is the effective multiplication coefficient; Σ r,g is the macroscopic removal cross section of the gth group, that is, the macroscopic total cross section minus the macroscopic self-scattering cross section, and r represents the removal.

5. The simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to claim 4, characterized in that: The calculation of the neutron flux density of each part of all axial grids of the control rod channel also includes: According to the neutron flux density of adjacent axial grids and the grid size in the axial direction, the neutron flux density of each part of all axial grids in the control rod channel is calculated as follows: Where z is the axial grid number, grid z+1 is located above grid z; g is the energy group number; is the neutron flux density of the gth group in the upper half of the grid z; is the neutron flux density of the gth group in the lower half of the grid z; φ z+1,g 、φ z,g 、φ z-1,g is the neutron flux density of the gth group in grids z+1, z and z-1; h z+1 、h z-1 is the axial length of grids z+1 and z-1; is the axial length of the upper half of the grid z; is the axial length of the lower half of the grid z; The grid size in the axial direction includes the axial length.

6. The simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to claim 5, characterized in that: The homogenization calculation and neutron flux effect correction are performed based on the neutron flux density and axial length of each part in the grid to obtain the homogenized cross section of all axial grids of the control rod channel. The homogenization calculation and neutron flux effect correction are performed based on the neutron flux density and axial length of each part in the grid, with the product of flux and length as the weight, to obtain the homogenized cross section of the axial grid of the control rod channel. The expression is: Among them, x represents the type of nuclear reaction; Σ x,z,g is the homogenized cross section of the gth group of grid z; is the gth group homogenized section of the upper half of the grid z; is the gth group homogenized section of the lower half of the grid z; The nuclear reaction types include total reaction, absorption reaction and scattering reaction.

7. A system using the simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to any one of claims 1 to 6, characterized in that: It includes data acquisition and preprocessing module, grid generation and establishment module, neutron flux solution module, homogenization calculation and neutron flux correction module; The data acquisition and preprocessing module collects and processes input data related to the sleeve-type control rods and the reactor core, confirms the structural parameters of the pebble-bed high-temperature gas-cooled reactor, and determines the mesh size of the reactor core model and the control rod insertion depth; The grid generation and establishment module generates an axial grid of the control rod channel and establishes the boundary position and coordinates of the grid; The neutron flux solving module solves the neutron flux density on all grids in the reactor core based on the neutron diffusion equation, and calculates the neutron flux density of each part in each axial grid of the control rod channel according to the neutron flux density of the adjacent axial grids of the control rod channel; The homogenization calculation and neutron flux correction module performs homogenization calculation based on the neutron flux density and axial length of each part in the grid, obtains the homogenized cross section of each grid through neutron flux effect correction, and completes the correction using the weighted average method.

8. 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 processor implements the steps of a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to any one of claims 1 to 6.

9. 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 a simulation calculation method for sleeve-type control rods of a pebble bed high-temperature gas-cooled reactor according to any one of claims 1 to 6 are implemented.

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