Analysis method and system for flow distribution of reactor core of pool type reactor and medium

Abstract

The invention provides an analysis method for flow distribution of a pool type reactor core. The analysis method comprises the following steps: calculating flows of a plurality of equivalent channels according to a parallel channel principle and a classical hydraulics relational expression so as to determine the flow of a standard fuel assembly channel, the flow of a following fuel assembly channel and the bypass flow of a bypass channel; determining reactor core inlet flow distribution factors of each standard fuel assembly and each following fuel assembly according to the three-dimensional CFD model of the reactor core and a computational fluid mechanics method; determining real reactor core inlet mass flow of each standard fuel assembly and each following fuel assembly based on the reactor core inlet flow distribution factor, the flow of the standard fuel assembly type channels and the flow of the following fuel assembly type channels; and determining the flow distribution of the reactor core according to the real reactor core inlet mass flow and bypass flow of each standard fuel assembly and each following fuel assembly.

Description

Technical Field

[0001] The present invention relates to the field of nuclear reactors, and in particular to an analysis method for core flow distribution of a pool-type reactor, an analysis system for core flow distribution of a pool-type reactor, and a computer-readable storage medium. Background Art

[0002] Pool-type research reactors adopt the technology of pool-type reactors at normal temperature and pressure, and can be used for multi-purpose objectives such as irradiation tests of fuel materials and isotope production. The pool-type reactor includes a core and a core support structure. The core is arranged in a heavy water tank, and plate-shaped fuel assemblies are arranged in the core. The coolant flows through the core from top to bottom in the reactor pool, and then flows out along the outlet nozzle of the support structure of the core.

[0003] According to the requirements of nuclear safety guidelines (such as HAD102 / 07 "Safety Design of Nuclear Power Plant Cores"), the design of in-core components should ensure that the coolant can be distributed to the fuel assemblies and related core structures in the core in an appropriate proportion to provide the required cooling conditions. Therefore, the study of the non-uniformity of core inlet flow distribution is a key content in reactor design.

[0004] There is an urgent need in the art for an analysis technology for core flow distribution of a pool-type reactor, which can accurately obtain the core flow distribution of the pool-type reactor while reasonably saving the calculation amount and meeting the requirements of rapid iterative optimization. The obtained distribution can be used to verify the rationality of the core inlet flow distribution of the reactor to ensure that the core inlet flow distribution meets the core design requirements. Summary of the Invention

[0005] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0006] The present invention provides an analysis method for core flow distribution of a pool-type reactor, an analysis system for core flow distribution of a pool-type reactor, and a computer-readable storage medium, which can accurately obtain the core flow distribution of the pool-type reactor while reasonably saving the calculation amount and meeting the requirements of rapid iterative optimization. The obtained distribution can be used to verify the rationality of the core inlet flow distribution of the reactor to ensure that the core inlet flow distribution meets the core design requirements.

[0007] Specifically, the above analysis method for core flow distribution of the pool-type reactor according to the first aspect of the present invention includes the steps of: calculating the flow rates of multiple equivalent channels according to the parallel channel principle and classical hydraulics relationships to determine the flow rates of the standard fuel assembly type channels, the flow rates of the follower fuel assembly type channels, and the bypass flow rates of the bypass channels; determining the core inlet flow distribution factors of each standard fuel assembly and each follower fuel assembly according to the three-dimensional CFD model of the reactor core and computational fluid dynamics methods; based on the core inlet flow distribution factors, the flow rates of the standard fuel assembly type channels, and the flow rates of the follower fuel assembly type channels, determining the true core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly; and determining the flow distribution of the reactor core according to the true core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly and the bypass flow rate.

[0008] Preferably, in an embodiment of the present invention, it further includes a verification step: obtaining the measured flow rates of each standard fuel assembly and each follower fuel assembly according to the reactor core flow distribution test; determining the bypass measured flow rate based on the measured flow rates of each standard fuel assembly and each follower fuel assembly; and verifying the true core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly and the bypass flow rate based on the measured flow rates of each standard fuel assembly, each follower fuel assembly, and the bypass measured flow rate.

[0009] Preferably, in an embodiment of the present invention, the reactor core flow distribution test is implemented by a test piece simulating the prototype structure of the reactor, and the resistance coefficient of the simulated fuel assembly of the test piece is the same as that of the prototype fuel assembly.

[0010] Preferably, in an embodiment of the present invention, the simulated fuel assembly includes a plate bundle area, a flow meter, and a resistance adjustment device.

[0011] Preferably, in an embodiment of the present invention, the step of determining the core inlet flow distribution factors of each standard fuel assembly and each follower fuel assembly includes: determining the core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly according to the three-dimensional CFD model and computational fluid dynamics methods; and determining the core inlet flow distribution factors of each standard fuel assembly and each follower fuel assembly according to the core inlet mass flow rates.

[0012] Preferably, in an embodiment of the present invention, the step of determining the core inlet flow distribution factors of the standard fuel assemblies and the follower fuel assemblies includes: determining a first average core inlet mass flow rate of the standard fuel assemblies based on the sum of the core inlet mass flow rates of the standard fuel assemblies and the number of the standard fuel assemblies; determining the core inlet flow distribution factors of the standard fuel assemblies according to the core inlet mass flow rates of the standard fuel assemblies and the first average inlet mass flow rate of the standard fuel assemblies; determining a first average core inlet mass flow rate of the follower fuel assemblies based on the sum of the core inlet mass flow rates of the follower fuel assemblies and the number of the follower fuel assemblies; and determining the core inlet flow distribution factors of the follower fuel assemblies according to the core inlet mass flow rates of the follower fuel assemblies and the first average inlet mass flow rate of the follower fuel assemblies.

[0013] Preferably, in an embodiment of the present invention, the step of determining the true core inlet mass flow rates of the standard fuel assemblies and the follower fuel assemblies includes: determining a second average core inlet mass flow rate of the standard fuel assemblies based on the flow rate of the standard fuel assembly channels and the number of the standard fuel assemblies; determining the true core inlet mass flow rates of the standard fuel assemblies based on the core inlet flow distribution factors of the standard fuel assemblies and the second average core inlet mass flow rate of the standard fuel assemblies; determining a second average core inlet mass flow rate of the follower fuel assemblies based on the flow rate of the follower fuel assembly channels and the number of the follower fuel assemblies; and determining the true core inlet mass flow rates of the follower fuel assemblies based on the core inlet flow distribution factors of the follower fuel assemblies and the second average core inlet mass flow rate of the follower fuel assemblies.

[0014] Preferably, in an embodiment of the present invention, the three-dimensional CFD model is established based on the standard fuel assemblies, the follower fuel assemblies, the fixed control rod assemblies, the irradiation channel assemblies, and the multi-channel assemblies of the reactor core.

[0015] In addition, the above-mentioned analysis system for core flow distribution of the pool-type reactor provided by the second aspect of the present invention includes a memory and a processor. Computer instructions are stored on the memory. The processor is connected to the memory and is configured to execute the computer instructions stored on the memory to implement the analysis method for core flow distribution of the pool-type reactor provided by any one of the above embodiments.

[0016] In addition, computer instructions are stored on the above-mentioned computer-readable storage medium provided by the third aspect of the present invention. When the computer instructions are executed by a processor, the analysis method for core flow distribution of the pool-type reactor provided by any one of the above embodiments is implemented. Brief Description of the Drawings

[0017] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components with similar related characteristics or features may have the same or similar reference numerals.

[0018] Figure 1 A schematic diagram showing an analysis system for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention;

[0019] Figure 2 A flowchart showing an analysis method for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention;

[0020] Figure 3 A schematic diagram showing the component layout of a pool-type reactor core provided according to some embodiments of the present invention;

[0021] Figure 4 A summary table showing the classification of reactor core flow channels provided according to some embodiments of the present invention;

[0022] Figure 5 A schematic diagram of the core of a three-dimensional CFD model provided according to some embodiments of the present invention;

[0023] Figure 6 A schematic diagram showing a test piece simulating the prototype structure of a reactor provided according to some embodiments of the present invention;

[0024] Figure 7 A schematic diagram showing a simulated standard fuel assembly provided according to some embodiments of the present invention;

[0025] Figure 8 A schematic diagram showing a simulated follower fuel assembly provided according to some embodiments of the present invention; and

[0026] Figure 9 A schematic diagram showing an analysis method for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention.

[0027] Reference Numerals:

[0028] 100: Analysis System;

[0029] 110: Memory;

[0030] 111: Computer-readable Storage Medium;

[0031] 120: Processor;

[0032] 200: Analysis method;

[0033] 310, 320, 330, 340, 350, 360: Positions;

[0034] 370, 380: Clearances;

[0035] 500: 3D CFD model;

[0036] 510: Mass flow rate inlet;

[0037] 520: Pressure outlet;

[0038] 600: Test piece;

[0039] 610: Water tank assembly;

[0040] 620: Cylinder simulation piece;

[0041] 630: Simulated core assembly;

[0042] 640: Core support simulation piece;

[0043] 700: Simulated standard fuel assembly;

[0044] 710: Plate bundle area;

[0045] 720: Venturi tube;

[0046] 800: Simulated follower fuel assembly;

[0047] 810: Plate bundle area;

[0048] 820: Venturi tube;

[0049] 900: Analysis method;

[0050] 910: Analysis part;

[0051] 911: Calculation part;

[0052] 912: Calculation part;

[0053] 920: Verification part; and

[0054] S210~S240: Steps. Detailed implementation manners

[0055] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are merely exemplary and should not be construed as imposing any limitation on the protection scope of the present invention.

[0056] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0057] In addition, the "upper", "lower", "left", "right", "top", "bottom", "horizontal", and "vertical" used in the following description should be understood as the orientations shown in this section and the relevant drawings. Such relative terms are only for convenience of description and do not represent that the devices described need to be manufactured or operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0058] It can be understood that although terms such as "first", "second", and "third" can be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first component, region, layer, and / or part discussed below can be referred to as the second component, region, layer, and / or part without departing from some embodiments of the present invention.

[0059] As described above, according to the requirements of the nuclear safety guidelines, the design of the in-core components should ensure that the coolant can be distributed to the fuel assemblies and the relevant in-core structures in the core in an appropriate proportion to provide the required cooling conditions. Therefore, the study of the non-uniformity of the core inlet flow rate distribution is a key content of reactor design.

[0060] The present invention provides an analysis method for the core flow rate distribution of a pool-type reactor, an analysis system for the core flow rate distribution of a pool-type reactor, and a computer-readable storage medium, which can accurately obtain the distribution of the core flow rate of the pool-type reactor while reasonably saving the calculation amount and meeting the requirements of rapid iterative optimization. The obtained distribution can be used to verify the rationality of the core inlet flow rate distribution of the reactor to ensure that the core inlet flow rate distribution meets the core design requirements.

[0061] In some non-limiting embodiments, the above-mentioned analysis method for the core flow rate distribution of a pool-type reactor provided by the first aspect of the present invention can be implemented via the above-mentioned analysis system for the core flow rate distribution of a pool-type reactor provided by the second aspect of the present invention.

[0062] Please refer to Figure 1 , Figure 1A schematic diagram of an analysis system for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention is shown.

[0063] As Figure 1 shown, a memory 110 and a processor 120 may be configured in the analysis system 100 for core flow distribution of the pool-type reactor. The memory 110 includes but is not limited to the above-mentioned computer-readable storage medium 111 provided in the third aspect of the present invention, on which computer instructions are stored. The processor 120 is connected to the memory 110 and is configured to execute the computer instructions stored on the memory 110 to implement the analysis method for core flow distribution of the pool-type reactor provided in the first aspect of the present invention.

[0064] The working principle of the above-mentioned analysis system for core flow distribution of the pool-type reactor will be described below first in conjunction with some embodiments of the analysis method for core flow distribution of the pool-type reactor. Those skilled in the art can understand that these embodiments of the analysis method for core flow distribution of the pool-type reactor are only some non-limiting implementation manners provided by the present invention, aiming to clearly show the main concept of the present invention and provide some specific solutions convenient for the public to implement, rather than being used to limit all functions or all working modes of the analysis system for core flow distribution of the pool-type reactor. Similarly, the analysis system for core flow distribution of the pool-type reactor is also a non-limiting implementation manner provided by the present invention, and does not limit the execution subject and execution order of each step in these analysis methods for core flow distribution of the pool-type reactor.

[0065] Please refer to Figure 2 , Figure 2 which shows a flowchart of an analysis method for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention.

[0066] As Figure 2 shown, the analysis method 200 for core flow distribution of the pool-type reactor may include step S210: calculating the flow rates of a plurality of equivalent channels according to the parallel channel principle and classical hydraulics relations to determine the flow rate of the standard fuel assembly class channel, the flow rate of the follower fuel assembly class channel, and the bypass flow rate of the bypass channel.

[0067] Please refer to Figure 3 and Figure 4 , Figure 3 which shows a schematic diagram of the component arrangement of the core of a pool-type reactor provided according to some embodiments of the present invention, Figure 4 which shows a summary table of reactor core flow channel classification provided according to some embodiments of the present invention.

[0068] In Figure 3 the shown embodiment, the fuel assemblies of the reactor can be divided into two categories: standard fuel assemblies and follower fuel assemblies. AsFigure 3 As shown, in the core of the pool-type reactor, standard fuel assemblies can be arranged at position 310, follower fuel assemblies at position 320, neutron source assemblies at position 330, irradiation channel assemblies at position 340, fixed control rod assemblies and / or irradiation channel assemblies at position 350, and multi-channel assemblies at position 360. Additionally, in addition to being distributed to each component in the core, the coolant also flows through the gaps 370 between the components. Moreover, the core is arranged in the heavy water tank, and the coolant also flows through the gap 380 between the components and the heavy water tank.

[0069] As Figure 4 shown, based on Figure 3 the positions of the components of the reactor core shown, the flow channels can be classified into 8 categories according to the components: standard fuel assemblies, follower fuel assemblies, neutron source assemblies, fixed control rod assemblies, irradiation channel assemblies, multi-channel assemblies, component gaps, and the gap between the components and the heavy water tank. Combining Figure 3 and Figure 4 it can be seen that the number of flow channels of the standard fuel assembly is 26, the number of flow channels of the follower fuel assembly is 6, the number of flow channels of the neutron source assembly is 2, the number of flow channels of the fixed control rod assembly is 1, the number of flow channels of the irradiation channel assembly is 6, and the number of flow channels of the multi-channel assembly is 2.

[0070] Figure 3 The embodiment shown is the component layout of the pool-type reactor under the first reactor net circulation condition. In some embodiments, for example, during the subsequent use of the pool-type reactor, position 360 may also be partially or fully replaced by an irradiation test device.

[0071] The analysis system for the core flow rate distribution of the pool-type reactor can merge the flow channels according to the flow channel positions of the components to determine multiple equivalent channels. The multiple equivalent channels can include standard fuel assembly type channels, follower fuel assembly type channels, and bypass channels.

[0072] In Figure 3 the embodiment shown, the 8 categories of flow channels divided according to the components can be merged according to the flow channel categories to form 8 groups of equivalent channels. Among them, the neutron source assembly channel, the fixed control rod assembly channel, the irradiation channel assembly channel, the multi-channel assembly channel, the component gap channel, and the gap between the components and the heavy water tank channel are the bypass channels of the reactor core.

[0073] After that, the analysis system can calculate the flow rates of the multiple equivalent channels according to the parallel channel principle and classical hydraulics relationships to determine the flow rate of the standard fuel assembly type channels, the flow rate of the follower fuel assembly type channels, and the bypass flow rate of the bypass channels. The bypass flow rate can be the sum of the flow rates of all other equivalent channels except the fuel assemblies, that is, the total flow rate minus the flow rates of the standard fuel assembly type channels and the follower fuel assembly type channels.

[0074] The analysis system can obtain a parallel channel by connecting all equivalent channels in parallel. According to the principle that the pressure drops of each sub-channel in the parallel channel are equal and the total flow rate of the parallel channel is equal to the sum of the flow rates of each sub-channel, the distribution of the flow rates of each sub-channel can be calculated using classical hydraulics relationships.

[0075] In Figure 3 and Figure 4 In the illustrated embodiment, the analysis system can perform flow rate distribution calculations for 8 groups of equivalent channels to obtain the effective cooling flow rate of the standard fuel assembly type, the effective cooling flow rate of the follower fuel assembly type, and the flow rates of the neutron source assembly, the fixed control rod assembly, the irradiation channel assembly, the multi-channel assembly, the assembly gap, and the gap between the assembly and the heavy water tank. Additionally, the sum of the flow rates of the neutron source assembly, the fixed control rod assembly, the irradiation channel assembly, the multi-channel assembly, the assembly gap, and the gap between the assembly and the heavy water tank is Figure 3 the bypass flow rate of the reactor core shown in

[0076] Thus, based on step S210, the analysis method 200 can achieve the overall reactor flow rate distribution calculation. The overall reactor flow rate distribution is obtained through one-dimensional calculation of the overall reactor flow rate distribution calculation method, which is convenient for calculation and has a fast iteration speed.

[0077] Please continue to refer to Figure 2 , the analysis method 200 can include step S220: determining the core inlet flow rate distribution factors of each standard fuel assembly and each follower fuel assembly according to the three-dimensional CFD model of the reactor core and the computational fluid dynamics method.

[0078] After determining the overall flow rate distribution of the reactor, the analysis system can establish a three-dimensional computational fluid dynamics (CFD) model based on the key structure of the reactor core to achieve the flow rate distribution calculation between reactor fuel assemblies.

[0079] The inlet setting of the three-dimensional CFD model can be a mass flow rate boundary, and the outlet setting can be a pressure outlet boundary. The mass flow rate boundary is the flow rate of the equivalent channels of the components for establishing the three-dimensional CFD model, which can be determined by subtracting the flow rates of the equivalent channels of the components not included in the three-dimensional CFD model and the leakage flow of the natural circulation valve from the total flow rate. The leakage flow of the natural circulation valve is a known fixed value.

[0080] The three-dimensional CFD model of the core structure can be a simplified three-dimensional CFD model that only considers fuel assemblies or a more refined three-dimensional CFD model that considers all components of the core.

[0081] In some embodiments, in a simplified three-dimensional CFD model of only the fuel assemblies being considered, the analysis system can establish a three-dimensional CFD model based only on the standard fuel assemblies and follower fuel assemblies of the reactor core.

[0082] In some embodiments, in a more refined three-dimensional CFD model that takes into account all components of the core, the analysis system can establish a three-dimensional CFD model based on all components of the reactor core.

[0083] In some embodiments, the three-dimensional CFD model can select key channel structures for modeling according to the actual situation, without the need for refined modeling of all channel structures within the reactor core. By means of partial refined modeling, the number of computational grids can be greatly reduced, saving computational effort.

[0084] Please refer to Figure 5 , Figure 5 which shows a schematic diagram of the core of a three-dimensional CFD model provided according to some embodiments of the present invention.

[0085] In Figure 5 the illustrated embodiment, the three-dimensional CFD model 500 is established based on Figure 3 the standard fuel assemblies, follower fuel assemblies, fixed control rod assemblies, irradiation hole channel assemblies, and multi-channel assemblies of the reactor core shown. Combining Figure 3 it can be seen that the neutron source assemblies, component gaps, and gaps between components and the heavy water tank of the reactor core are not considered in the three-dimensional CFD model 500.

[0086] The three-dimensional CFD model 500 can be provided with a mass flow inlet 510 and a pressure outlet 520. The analysis system can determine the mass flow boundary of the mass flow inlet 510 by deducting the flow share occupied by the component types not included in the three-dimensional CFD model. Specifically, the analysis system determines the mass flow boundary of the mass flow inlet 510 based on the total flow under the calculation conditions after deducting the flow of the neutron source assemblies, component gaps, and gaps between components and the heavy water tank and the leakage flow of the natural circulation valve.

[0087] After that, the analysis system can determine the core inlet flow distribution factors of the standard fuel assemblies and follower fuel assemblies according to the three-dimensional CFD model and the computational fluid dynamics method.

[0088] Specifically, the analysis system can use three-dimensional CFD modeling and computational fluid dynamics methods to calculate the flow rate distribution among reactor fuel assemblies, thereby determining the core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly, and thus obtaining the flow rate distribution among the fuel assemblies at the core inlet. Subsequently, based on the core inlet mass flow rate of each standard fuel assembly and the average inlet mass flow rate of the standard fuel assemblies, the core inlet flow rate distribution factor of each standard fuel assembly can be determined; correspondingly, based on the core inlet mass flow rate of each follower fuel assembly and the average inlet mass flow rate of the follower fuel assemblies, the core inlet flow rate distribution factor of each follower fuel assembly can be determined.

[0089] In some embodiments, the analysis system can determine the flow rate distribution among the fuel assemblies at the core inlet according to the results of the flow field calculation of the flow rate distribution among the reactor fuel assemblies. Then, the inlet flow rates of the fuel assemblies of the same category are normalized through formula (1) to obtain the core inlet flow rate distribution factor of each fuel assembly. Formula (1) is as follows:

[0090]

[0091] where σ i is the core inlet flow rate distribution factor of fuel assembly i; m i is the core inlet mass flow rate of fuel assembly i determined according to the three-dimensional CFD model and computational fluid dynamics methods, with the unit of kg / s; is the average core inlet mass flow rate of the fuel assemblies determined according to the three-dimensional CFD model and computational fluid dynamics methods, with the unit of kg / s.

[0092] Here, the average core inlet mass flow rate of the fuel assemblies can be determined by the above formula (2): the sum of the flow rates of a certain category of fuel assemblies determined according to the three-dimensional CFD model and computational fluid dynamics methods divided by the number n of fuel assemblies in this category. That is, the sum of the core inlet mass flow rates of each standard fuel assembly is divided by the number of standard fuel assemblies to determine the average core inlet mass flow rate of the standard fuel assemblies, and the sum of the core inlet mass flow rates of each follower fuel assembly is divided by the number of follower fuel assemblies to determine the average core inlet mass flow rate of the follower fuel assemblies.

[0093] In this way, through formulas (1) and (2), the core inlet flow rate distribution factor of each fuel assembly can be determined, and thus the non-uniformity of the inlet flow rate distribution of the fuel assemblies of the same category can be obtained.

[0094] After that, the analysis system can execute step S230: Determine the true core inlet mass flow rate of each standard fuel assembly and each follower fuel assembly based on the core inlet flow distribution factor, the flow rate of the standard fuel assembly class channels, and the flow rate of the follower fuel assembly class channels.

[0095] According to the total flow rate of each type of fuel assembly in the reactor total flow distribution result obtained in step S210, that is, the flow rate of the standard fuel assembly class channels and the flow rate of the follower fuel assembly class channels determined in S210, and combined with the core inlet flow distribution factor determined in step S220, the true core inlet mass flow rate of each fuel assembly can be obtained using formula (3) to determine the inlet flow distribution of each fuel assembly. Formula (3) is as follows:

[0096]

[0097] Where, is the true core inlet mass flow rate of fuel assembly i, with the unit of kg / s; is the average core inlet mass flow rate of a certain type of fuel assembly determined according to the flow rates of the standard fuel assembly class channels and the follower fuel assembly class channels in S210, with the unit of kg / s.

[0098] Here, the average core inlet mass flow rate of the standard fuel assembly can be determined by dividing the flow rate of the standard fuel assembly class channels by the number of standard fuel assemblies; correspondingly, the average core inlet mass flow rate of the follower fuel assembly can be determined by dividing the flow rate of the follower fuel assembly class channels by the number of follower fuel assemblies.

[0099] After that, as shown in formula (3), multiplying the core inlet flow distribution factor of each standard fuel assembly by the average core inlet mass flow rate of the standard fuel assembly can determine the true core inlet mass flow rate of each standard fuel assembly; multiplying the core inlet flow distribution factor of each follower fuel assembly by the average core inlet mass flow rate of the follower fuel assembly can determine the true core inlet mass flow rate of each follower fuel assembly.

[0100] In this way, according to the total flow rate of each type of fuel assembly in the reactor total flow distribution result obtained in step S210 combined with the core inlet flow distribution factor determined in step S220, the true core inlet mass flow rate of each fuel assembly can be obtained, thereby determining the inlet flow distribution of each fuel assembly.

[0101] Finally, the analysis system can execute step S240: Determine the flow distribution of the reactor core according to the true core inlet mass flow rate of each standard fuel assembly and each follower fuel assembly and the bypass flow rate.

[0102] The analysis method for core flow distribution of the pool-type reactor provided by the present invention combines the parallel-channel calculation for the overall reactor flow distribution and the three-dimensional calculation for the flow distribution among the reactor fuel assemblies to obtain the flow distribution results and bypass flow results at the core inlet of the fuel assemblies. The analysis method first calculates and determines the overall reactor flow distribution using empirical formulas, and then further determines the flow distribution among the reactor fuel assemblies using a refined three-dimensional computational fluid dynamics method. In this way, by combining the flow distribution calculation and the flow distribution calculation among the reactor fuel assemblies, it is possible to obtain the refined flow distribution results of each fuel assembly in the core, and at the same time, reasonably save the calculation amount to meet the requirements of rapid iterative optimization in the reactor design process.

[0103] In addition, since the core structure of the pool-type reactor is different from that of the traditional large-scale pressurized water reactor, the analysis method for core flow distribution of the pool-type reactor provided by the present invention may further include a verification step for further verifying the true core inlet mass flow rate and bypass flow rate of the fuel assemblies obtained from the above calculations.

[0104] The verification step can be achieved by conducting a core flow distribution test for the pool-type reactor. According to the core flow distribution test of the reactor, the measured flow rates of the standard fuel assemblies and the follower fuel assemblies are obtained.

[0105] Please refer to Figure 6 、 Figure 7 and Figure 8 , Figure 6 which shows a schematic diagram of a test piece simulating the prototype structure of the reactor provided by some embodiments of the present invention, Figure 7 which shows a schematic diagram of a simulated standard fuel assembly provided by some embodiments of the present invention, Figure 8 which shows a schematic diagram of a simulated follower fuel assembly provided by some embodiments of the present invention.

[0106] As Figure 6 shown, the core flow distribution test of the reactor can be achieved through a test piece 600 simulating the prototype structure of the reactor. The test piece 600 is designed based on the prototype structure of the reactor at a 1:1 ratio. The test piece 600 may include a water tank assembly 610 for simulating the reactor pool, a cylinder simulation piece 620 for simulating the heavy water tank, a simulated core assembly 630 for simulating the core, and a core support simulation piece 640 for simulating the core support structure. The simulated core assembly 630 is arranged in the cylinder simulation piece 620, and the simulated core assembly 630 may include at least one simulated standard fuel assembly 700 for simulating the standard fuel assembly as Figure 7 shown and at least one Figure 8The simulated follower fuel assembly 800 shown is used to simulate following the fuel assembly. The simulated standard fuel assembly 700 may include a plate bundle region 710. Correspondingly, the simulated follower fuel assembly 800 may include a plate bundle region 810. The simulated standard fuel assembly 700 and the simulated follower fuel assembly 800 utilize the plate bundle region to simulate the flow characteristics of the prototype plate fuel assembly.

[0107] The test piece uses a simulated fuel assembly with the same drag coefficient as the prototype fuel assembly to replace the real prototype fuel assembly. In addition to the plate bundle region, the simulated fuel assembly may further include a drag adjustment device and a flow meter.

[0108] In the test piece 600, each simulated standard fuel assembly 700 and each simulated follower fuel assembly 800 can make the drag coefficient the same as that of the prototype standard fuel assembly and the follower fuel assembly through the drag adjustment device, so as to simulate the drag characteristics of the prototype fuel assembly and ensure that the simulated core assembly 630 can characterize the core of the reactor prototype. In some embodiments, the drag adjustment device may include a contraction section and an adjustment cone, and the contraction section 720 may be a throttle ring.

[0109] In addition, each simulated standard fuel assembly 700 and each simulated follower fuel assembly 800 may include a flow meter. The test piece 600 can measure and obtain the measured flow of each standard fuel assembly by using the flow meter in each simulated standard fuel assembly 700, and measure and obtain the measured flow of each follower fuel assembly by using the flow meter in each simulated follower fuel assembly 800.

[0110] As Figure 7 and Figure 8 shown, each simulated standard fuel assembly 700 may include a venturi tube 720 for measuring the flow rate flowing through each simulated standard fuel assembly 700. Correspondingly, each simulated follower fuel assembly 800 may include a venturi tube 820 for measuring the flow rate flowing through each simulated follower fuel assembly 800. According to the flow rates measured by the venturi tube 720 and the venturi tube 820, the measured flow rates of each standard fuel assembly and each follower fuel assembly in the reactor core flow distribution test can be obtained. In some embodiments, the venturi tube may be replaced by other types of flow measurement devices.

[0111] In this way, through the reactor core flow distribution test carried out by the test piece 600 and each simulated standard fuel assembly 700 and each simulated follower fuel assembly 800 provided in its simulated core assembly 630, the measured flow rates of the simulated fuel assemblies including the measured flow rates of each standard fuel assembly and each follower fuel assembly can be determined.

[0112] Further, based on the measured standard fuel assembly measurement flow rate and follower fuel assembly measurement flow rate, the test core inlet flow rate distribution factor of each simulated fuel assembly in the test can be determined based on the inlet average flow rate. Here, the sum of the measured flow rates of each standard fuel assembly is divided by the number of standard fuel assemblies to determine the inlet average flow rate of the standard fuel assemblies, and the sum of the measured flow rates of each follower fuel assembly is divided by the number of follower fuel assemblies to determine the inlet average flow rate of the follower fuel assemblies.

[0113] After that, based on the standard fuel assembly measurement flow rate and the follower fuel assembly measurement flow rate, the analysis system can determine the bypass measurement flow rate.

[0114] In some embodiments, the component arrangement in the simulated core assembly 630 of the test piece 600 is the same as Figure 3 the component arrangement of the reactor core shown. The sum of the flow rates of all other channels except the simulated standard fuel assemblies and the simulated follower fuel assemblies is the bypass measurement flow rate. Specifically, the analysis system can obtain the total bypass measurement flow rate of the core by subtracting the measured flow rates of 32 groups of simulated fuel assemblies (26 groups of simulated standard fuel assemblies and 6 groups of simulated follower fuel assemblies) from the total flow rate. Here, the total flow rate during the reactor core flow rate distribution test can be determined according to the actual working conditions and is consistent with the total flow rate used in the above analysis method. In this embodiment, the calculation formula for the total bypass measurement flow rate is shown in Formula (4):

[0115]

[0116] where Q_total is the total flow rate during the reactor core flow rate distribution test, with the unit of kg / s; q j is the measured flow rate of the simulated fuel assembly j, with the unit of kg / s.

[0117] Thus, through the reactor core flow rate distribution test, the measured flow rates of each standard fuel assembly, each follower fuel assembly, and the bypass measurement flow rate can be obtained. Then, the analysis system can verify the true core inlet mass flow rate and bypass flow rate of each standard fuel assembly and each follower fuel assembly based on the measured flow rates of each standard fuel assembly, each follower fuel assembly, and the bypass measurement flow rate.

[0118] Here, the analysis calculation results can be the true core inlet mass flow rates and bypass flow rates of each standard fuel assembly and each follower fuel assembly obtained through steps S210 to S240 of the analysis method, and the verified test results can be the measured flow rates of each standard fuel assembly, the measured flow rates of each follower fuel assembly, and the bypass measured flow rate obtained in the verification step. By mutually verifying the analysis calculation results and the verified test results, if the analysis calculation results and the verified test results are basically matched, it can be determined that the analysis calculation results are reasonable, and further, the rationality of the reactor core structure design can be determined.

[0119] In addition, the analysis system can also compare the test core inlet flow distribution factor with the core inlet flow distribution factor to verify the rationality of the analysis calculation results of the research on inlet flow non-uniformity obtained based on the three-dimensional CFD model.

[0120] Please refer to Figure 9 , Figure 9 which shows a schematic diagram of an analysis method for core flow distribution of a pool-type reactor provided according to some embodiments of the present invention.

[0121] In Figure 9 the illustrated embodiment, the analysis method 900 for core flow distribution of a pool-type reactor may include an analysis part 910 and a verification part 920. The analysis part 910 may include a calculation part 911 for implementing the overall reactor flow distribution calculation and a calculation part 912 for implementing the flow distribution calculation between reactor fuel assemblies. The calculation part 911 for implementing the overall reactor flow distribution calculation is step S210 calculated by the parallel channel principle and classical hydrodynamics relations in the analysis method 200; the calculation part 912 for implementing the flow distribution calculation between reactor fuel assemblies is steps S220 to S230 calculated according to the three-dimensional CFD model and computational fluid dynamics method in the analysis method 200. The analysis part 910 may use the flow rates of the multiple equivalent channels determined in the calculation part 911 as the input of the three-dimensional CFD model in the calculation part 912, that is, the inlet setting of the three-dimensional CFD model.

[0122] Combined with Figure 2 it can be seen that the calculation part 911 for implementing the overall reactor flow distribution calculation can determine the overall reactor flow distribution, that is, the flow rates of the standard fuel assembly type channels and the follower fuel assembly type channels and the bypass flow rate. The calculation part 912 for implementing the flow distribution calculation between reactor fuel assemblies can, based on the input provided by the calculation part 911, determine the flow distribution between reactor fuel assemblies and further determine the true core inlet mass flow rates of each standard fuel assembly and each follower fuel assembly.

[0123] The verification part 920 can determine the test results according to the reactor core flow distribution test. The test results include the measured flow rates of each standard fuel assembly and each follower fuel assembly measured in the test piece, as well as the determined bypass measured flow rate.

[0124] The overall flow distribution and the flow distribution between fuel assemblies output by the analysis part 910 can be mutually verified with the test results determined by the verification part 920, so as to further determine the flow distribution of the fuel assemblies in the reactor core and verify the rationality of the reactor core structure design.

[0125] In summary, the analysis method for the reactor core flow distribution of the pool-type reactor proposed by the present invention realizes the calculation of the overall reactor flow distribution through the parallel channel principle and the calculation of classical hydraulics relations, and realizes the calculation of the flow distribution between the reactor fuel assemblies through the three-dimensional CFD model and the computational fluid dynamics method. It can not only obtain the fine flow distribution results of each fuel assembly in the reactor core, but also reasonably save the calculation amount and meet the requirements of rapid iterative optimization in the reactor design process.

[0126] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions that are illustrated and described herein or that are not illustrated and described herein but are understood by those skilled in the art.

[0127] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0128] The steps of a method or algorithm described in connection with the embodiments disclosed in this specification can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read from, and write to, the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium can reside in an ASIC. The ASIC can reside in a user terminal. In an alternative, the processor and the storage medium can reside as discrete components in a user terminal.

[0129] The foregoing description of the disclosure has been provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing flow distribution in a pool-type reactor core, characterized in that: Includes steps: Calculating the flow rates of multiple equivalent channels according to the parallel channel principle and classical hydraulic relations to determine the flow rate of the standard fuel assembly type channel, the flow rate of the follow-up fuel assembly type channel and the bypass flow rate of the bypass channel; Determine the core inlet flow distribution factor of each standard fuel assembly and each follower fuel assembly based on the three-dimensional CFD model of the reactor core and the computational fluid dynamics method; Determine the actual core inlet mass flow rate of each standard fuel assembly and each follower fuel assembly based on the core inlet flow distribution factor, the flow rate of the standard fuel assembly channel and the flow rate of the follower fuel assembly channel; as well as The flow distribution of the reactor core is determined according to the actual core inlet mass flow rates of the standard fuel assemblies and the follower fuel assemblies and the bypass flow rate.

2. The method for analyzing flow distribution in a pool-type reactor core according to claim 1, characterized in that: Also includes a verification step: According to the reactor core flow distribution test, the measured flow rate of each standard fuel assembly and the measured flow rate of each follower fuel assembly are obtained; Determining a bypass measurement flow rate based on the measurement flow rates of the standard fuel assemblies and the measurement flow rates of the follower fuel assemblies; as well as Based on the measured flow rates of the standard fuel assemblies, the measured flow rates of the follower fuel assemblies and the bypass measured flow rate, the actual core inlet mass flow rates of the standard fuel assemblies and the follower fuel assemblies and the bypass flow rate are verified.

3. The method for analyzing flow distribution in a pool-type reactor core according to claim 2, characterized in that: The reactor core flow distribution test is implemented by a test piece simulating a reactor prototype structure, and the resistance coefficient of the simulated fuel assembly of the test piece is the same as that of the prototype fuel assembly.

4. The method for analyzing flow distribution in a pool-type reactor core according to claim 3, characterized in that: The simulated fuel assembly comprises a plate bundle area, a flow meter and a resistance adjusting device.

5. The method for analyzing flow distribution in a pool-type reactor core according to claim 1, characterized in that: The step of determining the core inlet flow distribution factor of each standard fuel assembly and each follower fuel assembly comprises: Determining the core inlet mass flow rate of each standard fuel assembly and each follower fuel assembly according to the three-dimensional CFD model and computational fluid dynamics method; and According to the core inlet mass flow rate, a core inlet flow rate distribution factor of each standard fuel assembly and each follower fuel assembly is determined.

6. The method for analyzing flow distribution in a pool-type reactor core according to claim 5, characterized in that: The step of determining the core inlet flow distribution factor of each standard fuel assembly and each follower fuel assembly comprises: Determining a first average core inlet mass flow rate of the standard fuel assembly based on the sum of the core inlet mass flow rates of the standard fuel assemblies and the number of the standard fuel assemblies; Determining a core inlet flow rate distribution factor of each standard fuel assembly according to the core inlet mass flow rate of each standard fuel assembly and a first average inlet mass flow rate of the standard fuel assembly; Determining a first average core inlet mass flow rate of the following fuel assembly based on the sum of the core inlet mass flow rates of the following fuel assemblies and the number of the following fuel assemblies; and The core inlet flow rate distribution factor of each following fuel assembly is determined according to the core inlet mass flow rate of each following fuel assembly and the first average inlet mass flow rate of the following fuel assembly.

7. The method for analyzing flow distribution in a pool-type reactor core according to claim 1, characterized in that: The step of determining the actual core inlet mass flow rate of the standard fuel assembly and the follower fuel assembly comprises: Determining a second average core inlet mass flow rate of the standard fuel assembly based on the flow rate of the standard fuel assembly class channel and the number of the standard fuel assemblies; Determining a true core inlet mass flow rate of the standard fuel assembly based on the core inlet flow rate distribution factor of each standard fuel assembly and a second average core inlet mass flow rate of the standard fuel assembly; Determining a second average core inlet mass flow rate of the following fuel assembly based on the flow rate of the following fuel assembly-like channel and the number of the following fuel assemblies; and Based on the core inlet flow distribution factor of each of the following fuel assemblies and the second average core inlet mass flow rate of the following fuel assembly, the actual core inlet mass flow rate of the following fuel assembly is determined.

8. The method for analyzing flow distribution in a pool-type reactor core according to claim 1, characterized in that: The three-dimensional CFD model is established based on the standard fuel assemblies, the follower fuel assemblies, the fixed control rod assemblies, the irradiation channel assemblies and the multi-channel assemblies of the reactor core.

9. An analysis system for core flow distribution of a pool-type reactor, characterized in that: include: a memory having computer instructions stored thereon; as well as A processor is connected to the memory and is configured to execute computer instructions stored in the memory to implement the analysis method for core flow distribution of a pool-type reactor according to any one of claims 1 to 8.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the method for analyzing flow distribution in a pool-type reactor core according to any one of claims 1 to 8 is implemented.

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