Method and system for shortening the construction process of a pebble bed type high-temperature gas-cooled first loading core

Abstract

To provide a method and a system for shortening a construction process of a pebble bed type high-temperature gas cooling initial core.SOLUTION: A method and a system for shortening a construction process of a pebble bed type high-temperature gas cooling initial core include: constructing a physical calculation model of an initial loading and the construction process of the initial core on the basis of a material and a structural parameter of each aggregate; selecting a combustible poison addition scheme which can be executed by using a physical calculation model by adding a combustible poison to at least one of a black lead sphere and a fuel element; and evaluating safety of the initial loading and the construction process of the initial core regarding the realizable combustible poison addition scheme and selecting the optimum combustible poison addition scheme on the basis of the result of the safety evaluation. An amount of the black lead sphere is reduced, an operation output level in the initial core construction step is increased, and time of constructing the initial core is reduced so that economy of the pebble bed type high-temperature gas cooling core is significantly reduced.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the technical field of nuclear reactor core fuel management and operation, and more particularly to a method and system for shortening the construction process of a pebble bed type high temperature gas cooled initial core. [Background technology]

[0002] The fuel elements in a pebble bed high-temperature gas-cooled reactor are different from the fuel assemblies in conventional pressurized water reactors; they are generally spherical elements with a diameter of 6 cm, and tens to hundreds of thousands of such fuel elements are arranged throughout the core.

[0003] The fuel loading process of the pebble bed type high-temperature gas-cooled reactor is different from that of the pressurized water reactor, which loads the fuel assemblies into the entire core at one time. In contrast, the pebble bed type high-temperature gas-cooled reactor first loads a certain height of pure graphite balls (the outer shape is the same as the fuel elements and does not contain uranium) layer in the lower part of the core, and then loads a certain height of mixed fuel (fuel elements and graphite balls mixed in a certain ratio) on top of the graphite ball laying layer to reach the initial full loading height and complete the initial loading. After the initial loading, the construction of the initial loading core is started, that is, the reactor is operated at a certain power, and the mixed fuel continues to be loaded into the core at the initial full loading height, and the mixed fuel reaches the full height of the active part, and then the graphite balls in the pure graphite ball laying layer are gradually removed, and at the same time, the same amount of mixed fuel is added to the upper part of the core, and thus the height of the pure graphite ball laying layer is gradually decreased and the height of the mixed fuel is gradually increased until the entire active part is completely composed of mixed fuel, completing the construction of the initial loading core.

[0004] Therefore, the process of constructing the initial core loading can be described as a process of adding mixed fuel to the initial full loading height up to the active core height and removing the pure graphite sphere laying layer to achieve the full mixed fuel loading of the active core of the reactor. In the process of constructing the initial core loading, the number of fuel elements in the core is small, the excess reactivity of the reactor is low, and due to the limitation of the output of each fuel element, the operating output of the reactor is low, and the loading and unloading take a long time (the loading and unloading speed is proportional to the output of the reactor). Therefore, the main time is spent on removing the pure graphite sphere laying layer, which often takes several months. Therefore, if the height of the graphite sphere laying layer can be reduced at the initial full loading or the loading height / loading amount of the mixed fuel can be increased, the time for constructing the initial core loading can be shortened (the number of graphite spheres in the pure graphite sphere laying layer is reduced, and the removal time is shortened). In addition, when increasing the loading amount of the mixed fuel into the initial core loading, the average output of each fuel element can be reduced by increasing the number of fuel elements, and the operating output of the reactor in the process of constructing the initial core loading can be appropriately increased. As a result, the removal speed of the graphite spheres can be increased, and the time for constructing the initial core loading can be further shortened.

Summary of the Invention

[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and briefly explain some preferred embodiments. In this section, the abstract of this application, and the title of the invention, simplifications or omissions can be made to avoid obscuring the purpose. Such simplifications or omissions are not used to limit the scope of the present invention.

[0006] The present invention has been proposed in view of the above problems.

[0007] The first aspect according to an embodiment of the present invention provides a method for shortening the construction process of a pebble bed type high-temperature gas-cooled initial core loading, and based on the material and structural parameters of each assembly, constructs a physical calculation model of the initial core loading and the construction process of the initial core loading of a pebble bed type high-temperature gas-cooled reactor, adds combustible poison to graphite balls, fuel elements or both, selects an executable combustible poison addition scheme using the physical calculation model, and for the realizable combustible poison addition scheme, performs a safety assessment of the initial core loading and the construction process of the initial core loading, and selects an optimal combustible poison addition scheme based on the results of the safety assessment.

[0008] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high-temperature gas-cooled initial core loading described in the present invention, the material and structural parameters of each assembly include the diameter and height of the core, the loading amount and enrichment degree of the fuel elements, and the material and structural parameters of control rods, absorber balls, graphite reactor internals, carbon reactor internals, and metal reactor internals.

[0009] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high-temperature gas-cooled initial core loading described in the present invention, the construction of the physical calculation model divides the active region of the core in the radial direction into a plurality of linear flow paths with equal cross-sectional areas, and the linear flow paths are sequentially stacked in the axial direction from the center to the edge. divides the entire reactor into a plurality of "spectral zones" with equal volumes, and as the basic unit of energy spectrum calculation and fuel cycle simulation, the graphite ball laying layer and the mixed fuel elements are flowed layer by layer in the axial direction from top to bottom, assuming that there is no cross flow between the linear flow paths in the radial direction, and realizing the simulation of the core ball flow and the construction of the physical calculation model. After the physical calculation model is constructed, based on the calculation data, evaluate the influence of the mixing ball ratio, operating power, primary circuit flow rate, enrichment degree of the fuel elements, and number of cycles on the safety parameters of the core, obtain sensitivity parameters, and select an executable combustible poison addition scheme based on the sensitivity coefficients.

[0010] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high temperature gas cooled initial core described in the present invention, the selection of the combustible poison addition scheme is Considering that the graphite balls are directly taken out from the core in the construction process of the initial core and the influence on the subsequent reactor operation is much smaller than that of the fuel elements, preferably, combustible poison is added to the graphite balls, and according to the specific physical calculation results and operation requirements, combustible poison is added to both the fuel elements and By increasing the initial full loading mixed fuel loading amount of the pebble bed type high temperature gas cooled reactor and decreasing the height of the pure graphite ball laying layer, the construction time of the initial core is shortened, that is, by adding combustible poison, a certain negative reactivity is introduced into the original core loading, reducing the excess reactivity, thereby increasing the mixed fuel loading amount of the initial full loading of the pebble bed type high temperature gas cooled reactor, including The calculation of the negative reactivity of the combustible poison is TIFF0007712441000001.tif7170 Here, TIFF0007712441000002.tif6170 is the fast neutron multiplication factor, TIFF0007712441000003.tif7170 is the escape resonance absorption probability, TIFF0007712441000004.tif7170 is the thermal neutron utilization factor, TIFF0007712441000005.tif7170 is the effective nuclear fission neutron number, TIFF0007712441000006.tif7170 is the moderation non-leakage probability, TIFF0007712441000007.tif7170 indicates the diffusion non-leakage probability, When the loading of the mixed fuel is constant, when combustible poison is added to the core, the combustible poison absorbs some neutrons, and the proportion of all the absorbed thermal neutrons increases, so the thermal neutron utilization factor decreases and the reactivity of the core decreases. The formula is TIFF0007712441000008.tif14170 Here, TIFF0007712441000009.tif7170 indicates the reactivity of the reactor core.

[0011] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high temperature gas cooled initial loading reactor core described in the present invention, The addition amount of the combustible poison is not allowed to be too much or too little. If it is too much, even when the active part of the reactor core is fully loaded with mixed fuel, criticality cannot be achieved. If it is too little, the effect of increasing the loading amount of the mixed fuel is limited. That is, it further includes selecting an appropriate loading amount by calculation according to the physical calculation model.

[0012] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high temperature gas cooled initial loading reactor core described in the present invention, the safety evaluation of the process is For each selected combustible poison addition scheme, conduct a safety evaluation of the initial loading and the construction process of the initial loading reactor core, and confirm that the entire process of the combustible poison addition scheme meets the requirements of the safety parameters specified in the reactor safety analysis report, and does not exceed the safety limit under any operating conditions. This includes The safety parameters specified in the reactor safety analysis report include the primary circuit pressure of the reactor, the maximum temperature of the fuel element, the maximum single sphere output, the inlet and outlet temperatures, and the maximum discharge burnup.

[0013] As a preferred embodiment of the method for shortening the construction process of the pebble bed type high temperature gas cooled initial loading reactor core described in the present invention, the selection of the optimal combustible poison addition scheme is For the realizable combustible poison addition schemes that pass the safety evaluation, comprehensively consider the fuel economy, safety margin, construction time of the initial loading reactor core, operating power level of the reactor, and loading and unloading speed to determine the optimal combustible poison addition scheme. This includes

[0014] The second aspect according to the embodiment of the present invention provides a system for shortening the construction process of a pebble bed type high temperature gas cooled initial loading reactor core. A model construction unit used to construct a physical calculation model for the initial loading of a pebble bed type high temperature gas cooled reactor and the construction process of the initial loading core based on the material and structural parameters of each assembly, An addition scheme selection unit used to add burnable poison to graphite balls, fuel elements or both, and select a burnable poison addition scheme executable using the physical calculation model, For the realizable burnable poison addition scheme, an evaluation and selection unit used to perform a safety evaluation of the initial loading and the construction process of the initial loading core, and select an optimal burnable poison addition scheme based on the results of the safety evaluation, is included.

[0015] A third aspect according to an embodiment of the present invention provides a facility, and the facility includes a processor, a memory for storing instructions executable by the processor, and the processor is configured to call the instructions stored in the memory to execute the method described in any one of the embodiments of the present invention.

[0016] A fourth aspect according to an embodiment of the present invention provides a computer-readable storage medium having computer program instructions stored thereon, when the computer program instructions are executed by a processor, the method described in any one of the embodiments of the present invention is realized.

[0017] The beneficial effects of the present invention are as follows. In the method and system for shortening the construction process of a pebble bed type high-temperature gas-cooled initial loading core provided by the present invention, by reducing the height of the graphite ball laying layer, that is, reducing the amount of graphite balls, the procurement cost of graphite balls is significantly reduced, the investment in the power plant is saved, the economy is improved, and at the same time, the demand for graphite balls is reduced, the number of graphite balls taken out from the initial loading core is reduced, the construction time of the initial loading core is significantly shortened. Furthermore, in the present invention, the loading amount of the mixed fuel for the initial full loading is increased, the output level of the construction process of the initial reactor is increased, the loading and unloading speed is increased, the construction time of the initial loading core is further reduced, the trial operation period of the power plant is shortened, and the economy of the pebble bed type high-temperature gas-cooled reactor is significantly improved.

Brief Description of the Drawings

[0018] To more clearly explain the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments are briefly introduced below. Of course, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the figures,

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0019] In order to make the above objects, features and advantages of the present invention clearer and easier to understand, the following will describe in detail the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification. However, it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall be included in the protection scope of the present invention.

[0020] In order to facilitate a complete understanding of the present invention, many specific details will be described below. However, the present invention can also be implemented in other ways different from those described in this specification. Those skilled in the art can make similar expansions without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0021] Also, as used herein, "one embodiment" or "embodiment" refers to specific features, structures or characteristics that may be included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or selectively mutually exclusive embodiment from other embodiments.

[0022] The present invention will be described in detail in conjunction with schematic diagrams. When detailing the embodiments of the present invention, for the sake of ease of explanation, the cross-sectional views showing the structure of the device are enlarged partially regardless of the normal scale, and moreover, the said schematic diagrams are merely illustrative and do not limit the protection scope of the present invention. It should be noted that during actual production, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0023] Also, in the description of the present invention, as described, terms such as "upper, lower, inner, outer" indicate the orientation or positional relationship based on that shown in the accompanying drawings, and are only intended to facilitate and simplify the description of the present invention, and do not indicate or imply that the mentioned device or element must have a specific orientation and be structured and operated in a specific orientation, and thus should not be understood as a limitation of the present invention. Furthermore, the terms "first, second, or third" are merely for the purpose of explanation and should not be understood as indicating or suggesting relative importance.

[0024] In the present invention, the terms "mounting, connecting, coupling" should be understood in a broad sense unless otherwise specified or limited. For example, it may be fixedly connected, detachably connected or integrally connected, may be mechanically connected, may be electrically connected, may be directly connected, may be indirectly connected through an intermediate medium, or may be internal communication between the two members. A person skilled in the art can understand the specific meaning of the above terms in the present application according to the actual situation.

[0025] Example 1 Referring to FIGS. 1 to 6, an embodiment of the present invention provides a method for shortening the construction process of a pebble bed type high temperature gas cooled initial loading core. The fuel elements of a pebble bed type high temperature gas cooled reactor are generally spherical elements with a diameter of 6 cm (see FIG. 2), which are different from the fuel assemblies of conventional pressurized water reactors. Tens of thousands to hundreds of thousands of such fuel elements are arranged throughout the core. FIGS. 3 to 6 show a schematic diagram of the core loading and the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor. For this purpose, a method is proposed to increase the mixed fuel loading amount of the initial full loading of a pebble bed type high temperature gas cooled reactor, shorten the construction process of the initial loading core, achieve a reduction in the amount of graphite balls, increase the operating power level in the initial loading core construction stage, shorten the construction time of the initial loading core, and greatly improve the economic efficiency of the pebble bed type high temperature gas cooled reactor. The specific steps include the following S1 to S3.

[0026] S1: Based on the material and structural parameters of each assembly, construct a physical calculation model for the initial loading and the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor. Note that The material and structural parameters of each assembly include the diameter and height of the core, the loading amount and enrichment of the fuel elements, and the material and structural parameters of the control rods, absorber balls, graphite internal components, carbon internal components, and metal internal components.

[0027] Furthermore, the initial loading and the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor are different from those of a pressurized water reactor. There are different loading regions in the core, such as a graphite ball laying layer and mixed fuel. The heights of different loading regions gradually change (as shown in FIGS. 3 to 6), and the whole process is very complicated. Therefore, it is necessary to construct an accurate physical calculation model for analyzing and calculating the whole process.

[0028] As described, constructing a physical calculation model means dividing the active region of the core in the radial direction into a plurality of linear flow paths with equal cross-sectional areas, and the linear flow paths are sequentially stacked in the axial direction from the center to the edge, and The entire nuclear reactor is divided into a plurality of "spectral zones" with equal volumes. As the basic unit of energy spectrum calculation and fuel cycle simulation, the graphite ball laying layer and the mixed fuel elements are flowed layer by layer axially from top to bottom, assuming that there is no cross-flow between the linear flow paths in the radial direction, and realizing the simulation of the core ball flow and the construction of the physical calculation model. After the physical calculation model is constructed, based on the calculation data, evaluate the influence of the mixed ball ratio, operating power, primary circuit flow rate, enrichment degree of fuel elements, and number of cycles on the safety parameters of the core to obtain sensitivity parameters, and select a feasible burnable poison addition scheme based on the sensitivity coefficients.

[0029] S2: Add burnable poison to the graphite balls, fuel elements, or both, and select a feasible burnable poison addition scheme using the physical calculation model. Note that In the case of a pebble bed type high temperature gas cooled reactor, since all the fuel elements loaded at the initial loading are new, there is no fission poison, and the loading amount required to achieve criticality is small. Combined with the safety requirements of the shutdown margin, the mixed fuel loading at the initial full loading is only a part of the active core of the nuclear reactor (see Figure 4), and it is necessary to add a pure graphite ball laying layer at the bottom. If the height of the graphite ball laying layer is high, it will take a long time to remove all the graphite balls in it, that is, the construction time of the initial loading core will be long. Therefore, by increasing the mixed fuel loading amount of the initial full loading of the pebble bed type high temperature gas cooled reactor and reducing the height of the pure graphite ball laying layer, the construction time of the initial loading core can be shortened.

[0030] The pebble bed type high temperature gas cooled reactors built in China, whether it is HTR-10 or HTR-PM, do not use burnable poison. Burnable poison plays a role in offsetting most of the excess reactivity contained in the initial loading of the nuclear reactor. In the case of a pebble bed type high temperature gas cooled reactor, intuitively speaking, by adding burnable poison, a certain negative reactivity is introduced into the original core loading, reducing the excess reactivity, and thereby increasing the mixed fuel loading amount of the initial full loading.

[0031] Specifically, the calculation of the negative reactivity of the burnable poison is TIFF0007712441000010.tif7170 Here, TIFF0007712441000011.tif6170 is the fast neutron multiplication factor, TIFF0007712441000012.tif7170 is the resonance escape probability, TIFF0007712441000013.tif7170 is the thermal neutron utilization factor, TIFF0007712441000014.tif7170 is the effective number of fission neutrons, TIFF0007712441000015.tif7170 is the non-leakage probability of moderation, TIFF0007712441000016.tif7170 indicates the non-leakage probability of diffusion, When the loading of the mixed fuel is constant, adding burnable poison to the core causes the burnable poison to absorb some neutrons, and since the proportion of all absorbed thermal neutrons increases, the thermal neutron utilization factor decreases, and the reactivity of the core decreases. The formula is TIFF0007712441000017.tif14170 Here, TIFF0007712441000018.tif7170 indicates the reactivity of the core, In addition, it is physically possible in the nuclear reactor to add burnable poison to the graphite balls or the fuel elements, or both. The graphite balls are directly removed from the core during the construction process of the initial loading core (and may be partially reinserted into the nuclear reactor for cycling), and the impact on subsequent nuclear reactor operation is much smaller than that of the fuel elements (which generally pass through the core multiple times). Considering that the penalty of the burnable poison can be avoided or minimized, it is preferable to add burnable poison to the graphite balls. Of course, depending on the specific physical calculation results and operational requirements, burnable poison can also be added to the fuel elements or both.

[0032] Note that the amount of burnable poison added should not be too much or too little. If it is too much, the core cannot reach criticality even when the active part of the core is fully loaded with mixed fuel. If it is too little, the effect of increasing the mixed fuel loading amount is limited. That is, an appropriate loading amount is selected by calculation using a physical calculation model.

[0033] S3: For the realizable burnable poison addition scheme, conduct a safety assessment of the initial loading and the construction process of the initial loading core, and select the optimal burnable poison addition scheme based on the results of the safety assessment. Note that the safety assessment of the process For each of the selected burnable poison addition schemes, conduct a safety assessment of the initial loading and the construction process of the initial loading core, and confirm that the entire process of the burnable poison addition scheme meets the requirements of the safety parameters specified in the nuclear reactor safety analysis report, and that the safety limit is not exceeded under any operating conditions. This includes The safety parameters specified in the nuclear reactor safety analysis report include the primary circuit pressure of the nuclear reactor, the maximum temperature of the fuel element, the maximum single ball output, the inlet and outlet temperatures, and the maximum discharge burnup.

[0034] Furthermore, the selection of the optimal burnable poison addition scheme For the realizable burnable poison addition schemes that pass the safety assessment, comprehensively consider the fuel economy, safety margin, construction time of the initial loading core, operating power level of the nuclear reactor, and loading and unloading speeds to determine the optimal burnable poison addition scheme.

[0035] As described, in the method and system for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core provided by the present invention, by reducing the height of the graphite ball laying layer, that is, reducing the amount of graphite balls, the procurement cost of graphite balls is significantly reduced, the investment in the power plant is saved, the economy is improved, and at the same time, the demand for graphite balls is reduced, the number of graphite balls taken out from the initial loading core is reduced, the construction time of the initial loading core is significantly shortened. Furthermore, in the present invention, the loading amount of the mixed fuel for the initial full loading is increased, the output level of the construction process of the initial reactor is increased, the loading and unloading speed is increased, the construction time of the initial loading core is further reduced, the trial operation period of the power plant is shortened, and the economy of the pebble bed type high-temperature gas-cooled reactor is significantly improved.

[0036] The second aspect disclosed in the present invention is to provide a system for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core, a model construction unit used to construct a physical calculation model for the initial loading and the initial loading core construction process of the pebble bed type high-temperature gas-cooled reactor based on the material and structural parameters of each aggregate, and an addition scheme selection unit used to add combustible poison to graphite balls, fuel elements or both, and select an executable combustible poison addition scheme using the physical calculation model, and an evaluation and selection unit used to perform a safety evaluation of the initial loading and the construction process of the initial loading core for the realizable combustible poison addition scheme, and select the optimal combustible poison addition scheme based on the results of the safety evaluation.

[0037] The third aspect disclosed in the present invention is to provide equipment, including a processor and a memory for storing instructions executable by the processor, wherein the processor is configured to call the instructions stored in the memory to execute the method according to any one of the above items.

[0038] The fourth aspect disclosed in the present invention is Provide a computer-readable storage medium having computer program instructions stored thereon, When the computer program instructions are executed by a processor, the method according to any one of the preceding items is realized.

[0039] The present invention can be a method, an apparatus, a system and / or a computer program product, and the computer program product may include a computer-readable storage medium in which computer-readable program instructions for executing each aspect of the present invention are stored.

[0040] The computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution facility. The computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer-readable storage media include portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disk (DVD), memory stick, floppy disk, mechanically encoded device, punch cards or raised structures in grooves having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium used herein is not construed as a transient signal per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through an optical fiber cable), or electrical signals transmitted through wires.

[0041] Example 2 This embodiment is different from Embodiment 1 in that, in order to verify and explain the technical effects used in this method, a verification test of a method and system for shortening the construction process of a pebble bed type high-temperature gas-cooled initial loading core is provided.

[0042] In this embodiment, taking the demonstration project HTR-PM of a high-temperature gas-cooled reactor nuclear power plant as an example, the pure graphite ball laying layer at the bottom of the core before initial loading is about 6 m, and the number of pure graphite balls is about 240,000. The construction of the initial loading core is to gradually remove these 240,000 graphite balls and replace them with the same number of mixed fuels. Since the removal capacity of the HTR-PM fuel loading / removal system is 6,000 elements / day, the time until the completion of the initial loading core loading is about 240,000 / 6,000 = 40 days.

[0043] If the loading amount of the mixed fuel in the initial loading furnace is increased and the corresponding loading amount of the pure graphite balls is decreased, the construction time of the initial loading core can be significantly shortened. For example, if the loading amount of the mixed fuel is increased by 120,000, it can be shortened by 120,000 / 6,000 = 20 days. Thus, there are quite a few advantages both schedule-wise and economically. Therefore, in the method provided by the present invention, by reducing the height of the graphite ball laying layer, that is, reducing the amount of graphite balls, the procurement cost of the graphite balls can be significantly reduced, the investment in the power plant can be saved, the economy can be improved, and at the same time, the demand for graphite balls can be decreased, the number of graphite balls removed from the initial loading core can be reduced, the construction time of the initial loading core can be significantly shortened. Furthermore, in the present invention, the loading amount of the mixed fuel for the initial full loading is increased, the output level of the construction process of the initial reactor is increased, the loading / removal speed is increased, the construction time of the initial loading core is further reduced, the trial operation period of the power plant is shortened, and the economy of the pebble bed type high-temperature gas-cooled reactor is significantly improved.

[0044] It should be noted that the above-described embodiments are only for explaining the technical solutions of the present invention and do not limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art can make modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and these modifications or substitutions should be included in the scope of the claims of the present invention.

Claims

1. Constructing a physical calculation model for the initial loading and the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor based on the material and structural parameters of each assembly, and Adding combustible poison to the graphite balls, fuel elements or both, and selecting a combustible poison addition scheme that can be realized using the physical calculation model, and Performing a safety assessment of the initial loading and the construction process of the initial loading core for the realizable combustible poison addition scheme, and selecting an optimal combustible poison addition scheme based on the result of the safety assessment, characterized by including the above, a method for shortening the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor.

2. The material and structural parameters of each assembly include the diameter and height of the core, the loading amount and enrichment of the fuel elements, and the material and structural parameters of the control rods, absorber balls, graphite reactor internals, carbon reactor internals, and metal reactor internals. The method for shortening the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor according to Claim 1.

3. The construction of the physical calculation model is In the radial direction, dividing the active region of the core into a plurality of linear flow paths with equal cross-sectional areas, and sequentially stacking the linear flow paths in the order from the center to the edge in the axial direction, and Dividing the entire reactor into a plurality of "spectral zones" with equal volumes, and using the graphite ball laying layer and the mixed fuel elements as the basic units for energy spectrum calculation and fuel cycle simulation, flowing them layer by layer from top to bottom in the axial direction, assuming that there is no cross flow between the linear flow paths in the radial direction, and realizing the simulation of the core ball flow and the construction of the physical calculation model, and After the physical calculation model is constructed, based on the calculation data, evaluating the influence of the mixing ball ratio, operating power, primary circuit flow rate, enrichment of the fuel elements, and number of cycles on the safety parameters of the core, obtaining sensitivity parameters, and selecting a combustible poison addition scheme that can be realized based on the sensitivity parameters. The method for shortening the construction process of the initial loading core of a pebble bed type high temperature gas cooled reactor according to Claim 2.

4. The selection of the combustible poison addition scheme is The graphite balls are directly taken out from the core during the construction process of the initial core, combustible poison is added to the graphite balls, and according to the specific physical calculation results and operating requirements, combustible poison is added to the fuel elements and both of them. By increasing the initial full-loading mixed fuel loading amount of the pebble bed type high-temperature gas-cooled reactor and decreasing the height of the pure graphite sphere laying layer, the construction time of the initial loading core is shortened, that is, by adding a burnable poison, a certain negative reactivity is introduced into the original core loading, reducing the excessive reactivity, thereby increasing the initial full-loading mixed fuel loading amount of the pebble bed type high-temperature gas-cooled reactor, and The calculation of the negative reactivity of the burnable poison is Here, is the fast neutron multiplication factor, is the escape resonance absorption probability, is the thermal neutron utilization factor, is the effective number of fission neutrons, is the moderation non-leakage probability, indicates the diffusion non-leakage probability, When the loading of the mixed fuel is constant, when a burnable poison is added to the core, the burnable poison absorbs some neutrons, and the proportion of all absorbed thermal neutrons increases, so the thermal neutron utilization factor decreases, and the reactivity of the core decreases. The formula is Here, indicating the reactivity of the core, a method for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core according to claim 3.

5. If the addition amount of the burnable poison is too much, the core cannot reach criticality even when the active part of the core is fully loaded with the mixed fuel. If the addition amount of the burnable poison is too little, the effect of increasing the mixed fuel loading amount is limited. That is, further including selecting an appropriate loading amount by calculation according to the physical calculation model, a method for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core according to claim 4.

6. The safety evaluation of the construction process is For each selected burnable poison addition scheme, perform a safety evaluation of the initial loading and the construction process of the initial core, and confirm that the entire process of the burnable poison addition scheme meets the requirements of the safety parameters specified in the nuclear reactor safety analysis report, and does not exceed the safety limit under any operating conditions. The safety parameters specified in the nuclear reactor safety analysis report include the primary circuit pressure of the nuclear reactor, the maximum temperature of the fuel element, the maximum single sphere output, the inlet and outlet temperatures, and the maximum unloaded burnup, a method for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core according to claim 5.

7. The selection of the optimal burnable poison addition scheme is For a feasible combustible poison addition scheme that has passed the safety assessment, considering comprehensively the fuel economy, safety margin, construction time of the initial loading core, operating power level of the reactor, and loading / unloading speed, to determine the optimal combustible poison addition scheme, which is characterized by including shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core as described in claim 6.

8. A model construction unit used to construct a physical calculation model of the initial loading and the construction process of the initial loading core of a pebble bed type high-temperature gas-cooled reactor based on the material and structural parameters of each aggregate, An addition scheme selection unit used to add combustible poison to graphite balls, fuel elements, or both, and select a feasible combustible poison addition scheme using the physical calculation model, An evaluation / selection unit used to perform a safety assessment of the initial loading and the construction process of the initial loading core for the feasible combustible poison addition scheme, and select the optimal combustible poison addition scheme based on the results of the safety assessment, which is characterized by including a system for shortening the construction process of the pebble bed type high-temperature gas-cooled initial loading core.

9. A facility, including a processor, and a memory for storing instructions executable by the processor, wherein the processor is configured to call the instructions stored in the memory and execute the method according to any one of claims 1 to 7, which is characterized by the facility.

10. A computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are executed by a processor, realizing the method according to any one of claims 1 to 7, which is characterized by the computer-readable storage medium.

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