Modularization method for visualizing bubble movement during fuel breakage and leakage of lead-bismuth reactor

Abstract

The invention discloses a lead-bismuth reactor fuel damage leakage bubble movement visualization modeling method, which can screen out a visual fluid similar to high-temperature liquid lead-bismuth so as to carry out a more direct, simple and convenient visual experiment, and comprises the following steps: 1, carrying out dimensionless processing on three conservation equations of liquid lead-bismuth and gas to obtain dimensionless parameters; 2, carrying out dimensionless treatment on the motion equation of the gas in the liquid lead bismuth to obtain dimensionless parameters in the motion equation; 3, according to experimental conditions and physical significance of dimensionless parameters, selecting dimensionless numbers capable of ensuring that experimental phenomena of the prototype and the model are similar, enabling the dimensionless numbers to be equal in prototype fluid and model fluid, and solving to obtain a proportionality coefficient of the prototype and the model; and 4, based on the physical properties of the prototype fluid and the alternative fluid, the alternative gas and the fluid are screened, and if the non-dimensional number equation set is established, screening is completed. According to the method, the high-temperature liquid lead bismuth experiment can be simplified, the similarity of experimental data can be ensured, and meanwhile certain help can be provided for experimental design.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid modeling, and in particular relates to a modeling method for visualizing the movement of bubbles in a lead-bismuth pile fuel breakage and leakage. Background Art

[0002] When the fuel cladding of a lead-bismuth reactor is damaged, the fission products inside the cladding will be released into the lead-bismuth coolant through the rupture of the fuel rod cladding and migrate therein. In order to clarify the release mechanism of fission products, it is necessary to study it through experiments. However, due to the characteristics of liquid lead-bismuth being invisible, high in temperature, highly dangerous, and high in experimental cost, it brings great inconvenience to the fission gas release experiment of the lead-bismuth reactor. At the same time, the radioactivity of fission gas krypton and xenon gas makes it a certain safety hazard during the experiment. Therefore, an experimental modeling method is urgently needed. Using visible liquid instead of liquid lead-bismuth for fission gas release experiments can simplify the experiment and reduce safety hazards. At the same time, the corresponding proportional relationship between the parameters of the model fluid and the parameters of the prototype fluid can be found to realize the conversion of gas release experimental data between different fluids with low parameters. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a modeling method for visualizing the movement of bubbles in lead-bismuth pile fuel damage and leakage, so as to solve the problem that the temperature of liquid lead-bismuth is high and invisible.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for modeling the movement visualization of bubbles in a lead-bismuth fuel pile damage and leakage, comprising the following steps:

[0006] (1) The mass conservation equation, momentum conservation equation, and energy conservation equation of liquid lead and bismuth and gas are dimensionlessly processed to obtain the dimensionless parameters in the three conservation equations;

[0007] (2) The dimensionless parameters of the bubbling and jet motion equations of gas in high-temperature liquid lead and bismuth are obtained by dimensionless processing;

[0008] (3) Select dimensionless parameters that can characterize the similarity between prototype and model experiments according to the experimental conditions and the physical meaning of dimensionless parameters, and solve the corresponding proportionality coefficient as the correlation between the model and prototype data conversion;

[0009] (4) Based on the physical properties of the prototype fluid and the alternative fluid, select suitable alternative gases and fluids to ensure that the selected dimensionless parameters are equal in the prototype and model experiments or the error values ​​are within the preset range.

[0010] Preferably, based on the mass conservation equation, momentum conservation equation, and energy conservation equation of the liquid lead-bismuth, the parameters in the equations are dimensionless and brought into the original equations to obtain their dimensionless forms. The dimensionless equations of the liquid lead-bismuth are as follows:

[0011] The dimensionless mass conservation equation for liquid lead and bismuth is in the form of:

[0012]

[0013] The dimensionless momentum conservation equation for liquid lead and bismuth is in the form of:

[0014]

[0015] The dimensionless energy conservation equation for liquid lead and bismuth is in the form of:

[0016] Where: ρ represents the density of liquid lead bismuth / kgm -3 , x, y, z represent the lengths of the three directions / m, u x 、u y 、u z Represents the speed in three directions / ms -1 , L represents length / m, t represents time / s, t0 represents characteristic time / s, u0 represents characteristic speed / ms -1 , g represents the acceleration due to gravity / ms -2 , P represents the pressure of liquid lead bismuth / Pa, μ represents the viscosity of liquid lead bismuth / Pas -1 , T represents the temperature of liquid lead bismuth / K, C p Indicates the specific heat capacity of liquid lead-bismuth at constant pressure / J kg -1 K -1 ; Adding "'" to the upper right of a letter indicates that the letter is dimensionless;

[0017] The dimensionless parameters included in the equation are: Fr represents the Froude number, Eu represents the Euler number, Eu=ΔP / ρ0u0 2 , Re represents the Reynolds number, Re = ρ0u0L0 / μ0, Pr represents the Prandtl number, Pr = C P,0 μ0 / λ0, and define Among them, ΔP represents the pressure difference / Pa, λ represents the thermal conductivity, and the "0" in the lower right corner of the letter represents the characteristic quantity of the letter, C P,o Represents characteristic specific heat at constant pressure.

[0018] Preferably, the dimensionless processing of the mass conservation equation, momentum conservation equation, and energy conservation equation of the gas is as follows:

[0019] The dimensionless mass conservation equation for gases is in the form:

[0020]

[0021] The dimensionless momentum conservation equation for a gas is in the form:

[0022]

[0023] The dimensionless energy conservation equation for gases is in the form:

[0024]

[0025] The subscript "g" indicates a gas, where

[0026] Preferably, based on the momentum equation and energy equation in the jet motion equation of the gas in the high-temperature liquid lead-bismuth, the parameters in the equation are dimensionless and brought into the original equation to obtain its dimensionless form. The forms of the dimensionless equations are as follows:

[0027] The dimensionless momentum conservation equation in the jet motion equation of gas in high-temperature liquid lead-bismuth is in the form of:

[0028]

[0029] The dimensionless energy conservation equation in the jet motion equation of gas in high-temperature liquid lead-bismuth is in the form of:

[0030]

[0031] Where α is the thermal expansion coefficient, is the thermal diffusion coefficient of the fluid; adding "'" to the upper right of the letter indicates that the letter is dimensionless; the dimensionless parameters included in the equation are: Ri is the Richardson number, u g,0 is the characteristic gas velocity, Pe is the Picreau number, Pe = L0u g,0 / D T，0 , D T,0 is the characteristic thermal diffusivity.

[0032] Preferably, based on the bubbling motion equation of the gas in the high-temperature liquid lead-bismuth, the parameters in the equation are dimensionless and brought into the original equation to obtain its dimensionless equation form, and the form of the dimensionless equation is as follows:

[0033]

[0034] Among them, P o is the equilibrium pressure / Pa, R is the instantaneous radius of the bubble / m, R o is the bubble equilibrium radius / m, k is the polynomial index, μ l is the dynamic viscosity of the liquid / Pa s-1 , ρ l is the liquid density / kg m -3 , σ is the surface tension coefficient / N m; adding "'" to the upper right of the letter indicates that the letter is dimensionless;

[0035] The dimensionless parameters included in the dimensionless equation are:

[0036] Preferably, when screening for suitable replacement fluids, the physical properties of liquid lead and bismuth need to be used, and the calculation is as follows:

[0037] Liquid lead bismuth density: ρ = 11065-1.293T

[0038] Liquid lead bismuth viscosity:

[0039] Surface tension of liquid lead-bismuth: σ=0.4485-7.99×10 -5 T

[0040] Preferably, when screening for suitable alternative gases, the physical properties of fission gas need to be used, calculated as follows:

[0041] The fission gases in the lead-bismuth reactor fuel cladding are helium, xenon, and krypton, with proportions of 85%, 10%, and 5%, respectively. The physical properties of helium, xenon, and krypton are calculated using the material property calculation query platform AP1700. The fission gas temperature is 800K. According to the different internal pressures of the fuel rods, the physical properties of pure gases under different pressures are calculated, and the physical properties of the mixed gas are calculated using weighted methods.

[0042] Preferably, the dimensionless parameters selected to characterize the similarity between the prototype and model experiments are as follows:

[0043] Based on the dimensionless equation, a series of dimensionless numbers are obtained, Fr, Eu, Re, Pr, L1, R i , R1, R2, R3, according to the modeling principle and comprehensive consideration of the fission gas release process, the Reynolds number Re, Froude number Fr, and Richardson number R in the above dimensionless numbers are selected i And R1, R2, and R3 that characterize the bubble motion are used as dimensionless criterion parameters to characterize whether the prototype flow and model experiment are similar.

[0044] Preferably, the characteristic length, flow rate and time ratio of the fluid flow in the model experiment and the prototype are defined as the proportionality coefficient, and the Reynolds number and Froude number in the fluid flow in the prototype and the model experiment are kept equal to obtain the calculation formula of the proportionality coefficient, as shown below:

[0045]

[0046] Among them, f urepresents the speed proportionality factor, f L represents the scale factor, f t represents the time proportional coefficient, M represents the model test, and P represents the prototype flow; the above proportional coefficient is used to express the conversion proportional relationship between the data in the model after modeling and the prototype experiment.

[0047] Preferably, according to the physical properties of liquid lead and bismuth and the physical properties of the initially screened alternative fluid and the flow rate and scale ratio coefficient calculation formula, assuming that the flow rate and scale of the fluid flow in the prototype are both unit "1", the specific values ​​of the flow rate and scale ratio coefficient are calculated, and the values ​​are used as important parameters for subsequent dimensionless number calculations; through the above process, the Reynolds number and Froude number of the model and the prototype are guaranteed to be equal. In order to ensure that the release process of the fission gas includes bubbling and jetting, it is necessary to calculate the R of the model and the prototype respectively on the basis of the above process. i , R1, R2, R3 dimensionless numbers. If the above dimensionless numbers of the model and the prototype are equal or the deviation is within the preset range, they are considered equal, that is, the model and the prototype are similar, and the screened fluid can be used as an adaptive alternative fluid to complete the process modeling.

[0048] Technical problems and advantages solved by the present invention:

[0049] Technical problems solved by the present invention:

[0050] 1) Since the method of the present invention is based on the derivation of the basic equation of liquid lead-bismuth to screen out the visualized fluid, the method of the present invention solves the problem that the release and migration of fission products after the lead-bismuth reactor fuel is damaged is difficult to visualize and measure;

[0051] 2) Since the method of the present invention is based on high-temperature liquid lead-bismuth to screen out room-temperature fluid, the method of the present invention solves the problem of experimenting in a high-temperature environment of a real lead-bismuth fluid and reduces safety hazards;

[0052] The present invention has the following advantages and beneficial effects:

[0053] 1) Since the method of the present invention is derived based on the basic fluid control equations and motion equations, the modeling method provided by the present invention has a wide range of applications and is highly applicable in scenarios of interaction between gas and invisible fluids.

[0054] 2) Since the method of the present invention can screen out normal temperature and pressure fluids based on actual high temperature and high pressure fluids for research, the modeling method provided by the present invention can reduce experimental parameters and visualize the experiment, which can greatly simplify the experiment.

[0055] 3) The modeling method provided by the present invention is derived based on basic control equations and is simple and easy to understand. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a modeling flow chart.

[0057] Figure 2 This is the corresponding diagram of the pressure relationship between the prototype gas and the model gas.

[0058] Figure 3 It is the velocity proportionality coefficient diagram of gas and fluid.

[0059] Figure 4 It is the scale factor diagram of gas and fluid.

[0060] Figure 5 This is the time proportional coefficient diagram of gas and fluid.

[0061] Figure 6 Figure 2 shows the Ri numerical results of the prototype and the model.

[0062] Figure 7 Figure 2 shows the R1 numerical results of the prototype and the model.

[0063] Figure 8 Figure 2 is the R2 numerical result diagram of the prototype and the model.

[0064] Fig. 9 Figure 2 shows the R3 numerical results of the prototype and the model. DETAILED DESCRIPTION

[0065] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0066] The present invention discloses a modeling method for visualizing the movement of bubbles in a lead-bismuth pile fuel damage leakage, which can screen out a visualized fluid similar to high-temperature liquid lead-bismuth to conduct a more direct and convenient visualization experiment, and comprises the following steps: step 1: according to the mass conservation equation, momentum conservation equation and energy conservation equation of liquid lead-bismuth and gas, dimensionless processing is performed on them to obtain dimensionless parameters contained in the dimensionless forms of the three conservation equations; step 2: according to the motion equation of gas in liquid lead-bismuth (bubble and jet equation), dimensionless processing is performed on them to obtain dimensionless parameters contained in the dimensionless forms; step 3: according to the experimental conditions and the physical meaning of the dimensionless parameters, dimensionless numbers that can ensure the similarity of the experimental phenomena of the prototype and the model are selected, and the dimensionless numbers are made equal in the prototype fluid and the model fluid to obtain a dimensionless number equation group, and the proportional coefficient of the prototype and the model is obtained by solving; step 4: based on the physical properties of the prototype fluid and the substitute fluid, alternative gases and fluids are screened, and if the dimensionless number equation group is established, the screening is completed. The method disclosed in the present invention can simplify the high-temperature liquid lead-bismuth experiment and ensure the similarity of experimental data, and can also provide certain help for experimental design. The specific description is as follows:

[0067] The mass conservation equation, momentum conservation equation and energy conservation equation of liquid lead bismuth and gas are dimensionless processed to obtain dimensionless parameters in the three conservation equations.

[0068] In this embodiment, the dimensionless parameters obtained for liquid lead bismuth and gas are in the same form, as shown below:

[0069]

[0070] The dimensionless parameters of the bubbling and jet motion equations of gas in high-temperature liquid lead and bismuth are obtained by dimensionless treatment.

[0071] In this embodiment, the extracted dimensionless parameters are as follows:

[0072]

[0073] According to the experimental conditions and the physical meaning of dimensionless parameters, dimensionless parameters that can characterize the similarity between prototype and model experiments are selected;

[0074] In this embodiment, based on the dimensionless equation, a series of dimensionless numbers are obtained, Fr, Eu, Re, Pr, L1, R i , R1, R2, R3, according to the modeling principle, dimensionless parameters and comprehensive consideration of the fission gas release process, the Reynolds number (Re), Froude number (Fr), Richardson number (R i ) and R1, R2, and R3 (characterizing bubble motion) are used as dimensionless criterion parameters to characterize whether the prototype flow and model experiment are similar.

[0075] Based on the prototype fluid, the selected alternative gases and fluids ensure that the selected dimensionless parameters are equal or the error values ​​are within the preset range in the prototype and model experiments;

[0076] In this embodiment, the temperature of liquid lead-bismuth is calculated as 673K, and the physical properties required for calculation are: density of liquid lead-bismuth: 10216kg / m 3 ; Liquid lead bismuth viscosity: 1.516mPa s; Liquid lead bismuth surface tension: 0.3992N / m.

[0077] In this embodiment, the fission gas in the lead-bismuth reactor fuel cladding is mainly helium, xenon, and krypton, with proportions of 85%, 10%, and 5% respectively. The physical properties of helium, xenon, and krypton are calculated using the material property calculation query platform AP1700. The fission gas temperature is 800K. According to the different internal pressures of the fuel rods, the physical properties of pure gases under different pressures are calculated, and the physical properties of the mixed gas are calculated by weighted calculation. The results of some gas properties are shown in the figure below:

[0078] pressure Physical property category Helium Xenon Krypton Mixed gas properties 10MPa <![CDATA[Density (kg / m 3 )]]> 5.9285 196.1656 123.2484 30.8182 Viscosity (mPa s) 0.04 0.04 0.04 0.04 2MPa <![CDATA[Density (kg / m 3 )]]> 1.2 39.46 25.094 6.22 Viscosity (mPa s) 0.04 0.04 0.04 0.04 1MPa <![CDATA[Density (kg / m 3 )]]> 0.6 19.735 12.572 3.1121 Viscosity (mPa s) 0.04 0.04 0.04 0.04 0.4MPa <![CDATA[Density (kg / m 3 )]]> 0.2406 7.895 5.0352 1.2458 Viscosity (mPa s) 0.04 0.04 0.04 0.04

[0079] In this embodiment, the characteristic length, flow velocity and time ratio of the model experiment and the prototype flow are defined as the proportionality coefficient, so that the Reynolds number and Froude number of the fluid flow in the prototype and the model experiment remain equal, and the expression of the proportionality coefficient can be solved:

[0080]

[0081] In this embodiment, based on the physical properties of liquid lead and bismuth and the physical properties of the initially screened alternative fluids and the flow rate and scale ratio coefficient calculation formula, and assuming that the flow rate and scale of the fluid flow in the prototype are both unit "1", the specific values ​​of the flow rate and scale ratio coefficient can be calculated as a reference for subsequent dimensionless number calculations and experimental design. In order to ensure the release process of fission gas (including bubbling and jetting), it is necessary to calculate the R of the model and prototype respectively on the basis of the above. i ,R1,R2,R3 dimensionless numbers. If the above dimensionless numbers of the model and prototype are equal or the deviation is within a certain range, they are considered equal, which ensures that the model and prototype are similar.

[0082] In this embodiment, through analysis and calculation, helium is finally selected as the alternative gas (corresponding to different prototype gas pressures), and the corresponding relationship between the alternative gas pressure and the prototype gas pressure at different operating points is: 3.59MPa-10MPa, 1.04MPa-3MPa, 0.72MPa-2MPa, 0.36MPa-1MPa, 0.14MPa-0.4MPa, 0.104MPa-0.3MPa. Figure 2 As shown: A mixed solution of acetonitrile and water with a molar ratio of 1:2 is selected as the alternative liquid. The density of acetonitrile solution at room temperature is 786 kg / m 3 , then the density of the mixed solution with acetonitrile and water in a molar ratio of 1:2 is 916 kg / m 3 .

[0083] Based on the physical properties of the alternative gas and fluid and the relationship between velocity, scale and time proportionality coefficient, its specific values ​​can be calculated as follows: Figure 3 , Figure 4 and Figure 5 As shown: It can be seen from the figure that the three proportional coefficients of gas and fluid are very close, so the proportional coefficient of the fluid can be used as the unified proportional coefficient of the two.

[0084] Based on the above analysis and calculation results, the dimensionless number R of the prototype and model can be calculated i , R1, R2, and R3, and the results are as follows Figure 6 , Figure 7 , Figure 8 and Fig. 9 shown.

[0085] It can be seen from the figure that the four dimensionless numbers of the prototype and the model are close in value, except for R1, but they are at the same order of magnitude. Therefore, it can be considered that the screened alternative fluids and alternative gases are similar to the prototype.

[0086] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A simulation method for visualizing the movement of bubbles in a lead-bismuth fuel pile, characterized in that: The steps include: (1) The mass conservation equation, momentum conservation equation, and energy conservation equation of liquid lead and bismuth and gas are dimensionlessly processed to obtain the dimensionless parameters in the three conservation equations; (2) The dimensionless parameters of the bubbling and jet motion equations of gas in high-temperature liquid lead and bismuth are obtained by dimensionless processing; (3) Select dimensionless parameters that can characterize the similarity between prototype and model experiments according to the experimental conditions and the physical meaning of dimensionless parameters, and solve the corresponding proportionality coefficient as the correlation between the model and prototype data conversion; (4) Based on the physical properties of the prototype fluid and the alternative fluid, select suitable alternative gases and fluids to ensure that the selected dimensionless parameters are equal in the prototype and model experiments or the error values ​​are within the preset range.

2. The method for modeling the movement visualization of bubbles in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: Based on the mass conservation equation, momentum conservation equation, and energy conservation equation of the liquid lead-bismuth, the parameters in the equations are non-dimensionalized and brought into the original equations to obtain their dimensionless forms. The dimensionless equations of the liquid lead-bismuth are as follows: The dimensionless mass conservation equation for liquid lead and bismuth is in the form of: The dimensionless momentum conservation equation for liquid lead and bismuth is in the form of: The dimensionless energy conservation equation for liquid lead and bismuth is in the form of: Where: ρ represents the density of liquid lead bismuth / kgm -3 , x, y, z represent the lengths of the three directions / m, u x 、u y 、u z Represents the speed in three directions / ms -1 , L represents length / m, t represents time / s, t0 represents characteristic time / s, u0 represents characteristic speed / ms -1 , g represents the acceleration due to gravity / ms -2 , P represents the pressure of liquid lead bismuth / Pa, μ represents the viscosity of liquid lead bismuth / Pas -1 , T represents the temperature of liquid lead bismuth / K, C p Indicates the specific heat capacity of liquid lead-bismuth at constant pressure / Jkg -1 K -1 ; Add "'" to the upper right of the letter to indicate that the letter is dimensionless; The dimensionless parameters included in the equation are: Fr represents the Froude number, Eu represents the Euler number, Eu=ΔP / ρ0u0 2 , Re represents the Reynolds number, Re = ρ0u0L0 / μ0, Pr represents the Prandtl number, Pr = C P,0 μ0 / λ0, and define Among them, ΔP represents the pressure difference / Pa, λ represents the thermal conductivity, and the "0" in the lower right corner of the letter represents the characteristic quantity of the letter, C P,o Represents characteristic specific heat at constant pressure.

3. The method for modeling the visualization of bubble movement in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: The dimensionless treatment of the gas mass conservation equation, momentum conservation equation, and energy conservation equation is as follows: The dimensionless mass conservation equation for gases is in the form: The dimensionless momentum conservation equation for a gas is in the form: The dimensionless energy conservation equation for gases is in the form: The subscript "g" indicates gas, where 4. The method for modeling the movement visualization of bubbles in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: Based on the momentum equation and energy equation in the jet motion equation of the gas in the high-temperature liquid lead-bismuth, the parameters in the equation are non-dimensionalized and brought into the original equation to obtain its dimensionless form. The forms of the dimensionless equations are as follows: The dimensionless momentum conservation equation in the jet motion equation of gas in high-temperature liquid lead-bismuth is in the form of: The dimensionless energy conservation equation in the jet motion equation of gas in high-temperature liquid lead-bismuth is in the form of: Where α is the thermal expansion coefficient, is the thermal diffusion coefficient of the fluid; adding "'" to the upper right of the letter indicates that the letter is dimensionless; the dimensionless parameters included in the equation are: Ri is the Richardson number, u g,0 is the characteristic gas velocity, Pe is the Picreau number, Pe = L0u g,0 / D T，0 , D T,0 is the characteristic thermal diffusivity.

5. The method for modeling the visualization of bubble movement in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: Based on the bubbling motion equation of the gas in the high-temperature liquid lead-bismuth, the parameters in the equation are non-dimensionalized and substituted into the original equation to obtain its dimensionless equation form. The form of the dimensionless equation is as follows: Among them, P o is the equilibrium pressure / Pa, R is the instantaneous radius of the bubble / m, R o is the bubble equilibrium radius / m, k is the polynomial index, μ l is the dynamic viscosity of the liquid / Pa s -1 , ρ l is the liquid density / kg m -3 , σ is the surface tension coefficient / Nm; adding "'" to the upper right of the letter indicates that the letter is dimensionless; The dimensionless parameters included in the dimensionless equation are:

6. The method for modeling the visualization of bubble movement in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: When screening for suitable replacement fluids, the physical properties of liquid lead and bismuth need to be used, calculated as follows: Liquid lead bismuth density: ρ = 11065-1.293T Liquid lead bismuth viscosity: Surface tension of liquid lead-bismuth: σ=0.4485-7.99×10 -5 T.

7. The method for modeling the visualization of bubble movement in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: When screening for suitable alternative gases, the physical properties of fission gases need to be used, calculated as follows: The fission gases in the lead-bismuth reactor fuel cladding are helium, xenon, and krypton, with proportions of 85%, 10%, and 5%, respectively. The physical properties of helium, xenon, and krypton are calculated using the material property calculation query platform AP1700. The fission gas temperature is 800K. According to the different internal pressures of the fuel rods, the physical properties of pure gases under different pressures are calculated, and the physical properties of the mixed gas are calculated using weighted methods.

8. The method for modeling the movement visualization of bubbles in lead-bismuth fuel pile damage leakage according to claim 1, characterized in that: The dimensionless parameters selected to characterize the similarity between prototype and model experiments are as follows: Based on the dimensionless equation, a series of dimensionless numbers are obtained, Fr, Eu, Re, Pr, L1, R i , R1, R2, R3, according to the modeling principle and comprehensive consideration of the fission gas release process, the Reynolds number Re, Froude number Fr, and Richardson number R in the above dimensionless numbers are selected i And R1, R2, and R3 that characterize the bubble motion are used as dimensionless criterion parameters to characterize whether the prototype flow and model experiment are similar.

9. The method for modeling the visualization of bubble movement in lead-bismuth pile fuel damage leakage according to claim 8, characterized in that: Define the ratio of the characteristic length, velocity and time of the fluid flow in the model experiment and the prototype as the proportional coefficient, and keep the Reynolds number and Froude number in the prototype and the model experiment equal to obtain the calculation formula of the proportional coefficient, as shown below: Among them, f u represents the speed proportionality factor, f L represents the scale factor, f t represents the time proportional coefficient, M represents the model test, and P represents the prototype flow; the above proportional coefficient is used to express the conversion proportional relationship between the data in the model after modeling and the prototype experiment.

10. The method for modeling the movement visualization of bubbles in lead-bismuth fuel pile damage leakage according to claim 9, characterized in that: According to the physical properties of liquid lead and bismuth and the physical properties of the initially screened alternative fluids, as well as the flow rate and scale ratio coefficient calculation formula, assuming that the flow rate and scale of the fluid flow in the prototype are both unit "1", the specific values ​​of the flow rate and scale ratio coefficient are calculated, which are used as important parameters for the subsequent dimensionless number calculation; through the above process, the Reynolds number and Froude number of the model and the prototype are guaranteed to be equal. In order to ensure that the release process of fission gas includes bubbling and jetting, it is necessary to calculate the R of the model and the prototype respectively on the basis of the above process. i , R1, R2, R3 dimensionless numbers. If the above dimensionless numbers of the model and the prototype are equal or the deviation is within the preset range, they are considered equal, that is, the model and the prototype are similar, and the screened fluid can be used as an adaptive alternative fluid to complete the process modeling.

Images