Rapid calculation method for fission delayed nuclear radiation fluence or dose under impact wave influence

Abstract

The invention discloses a rapid calculation method for fission delayed nuclear radiation fluence or dose under the impact wave influence, which solves the problem of low particle fluence or dose calculation speed in a fission delayed nuclear radiation environment under the impact wave influence in the prior art, and considers the complex distribution of air density under the impact wave disturbance. The method can be used for calculating the fission delayed nuclear radiation environment under the impact wave influence, and can provide support for nuclear radiation environment evaluation and personnel and equipment nuclear radiation shielding design in a specific scene. In addition, calculation is carried out based on the mapping relation between the air quality thickness and the nuclear radiation environment, and compared with simulation of a traditional Monte Carlo method, the calculation time is obviously shortened, and the calculation speed is effectively increased.

Description

Technical Field

[0001] This invention relates to a method for calculating flux or dose, specifically a rapid method for calculating the flux or dose of slow-emission nuclear radiation from fission under the influence of a shock wave. Background Technology

[0002] Nuclear power generation has been widely used around the world, and the safety of nuclear reactors has long been a major concern. Major nuclear accidents, whether caused by natural disasters or human error, are typically accompanied by powerful explosions. The spontaneous decay of fission product nuclei produces slow-release fission radiation. Because most fission product nuclei have long half-lives, the transport of this slow-release radiation is inevitably affected by shock waves. Therefore, the impact of shock waves must be considered during the transport of slow-release fission radiation to reasonably assess the nuclear radiation environment.

[0003] Currently, the Monte Carlo method is widely used to study nuclear radiation transport problems. However, the complex air density distribution under the influence of shock waves increases the difficulty of modeling with the Monte Carlo method. Furthermore, for particle transport problems in large-scale spaces and complex geometries, simulation using the Monte Carlo method inevitably requires a significant amount of computation time, resulting in a substantial decrease in the calculation speed of particle fluence or dose compared to simulating radiation transport without the influence of shock waves. To address these issues, it is necessary to develop a rapid calculation method for the fluence or dose of slow-initiated nuclear radiation from fission under the influence of shock waves. Summary of the Invention

[0004] To address the problem of slow calculation speed of fission slow-emission nuclear radiation particle fluence or dose under the influence of shock waves in existing technologies, this invention provides a rapid calculation method for fission slow-emission nuclear radiation fluence or dose under the influence of shock waves.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A rapid calculation method for the slow-release nuclear radiation flux or dose under the influence of a shock wave, characterized by the following steps:

[0007] Step 1: Set up the first radiation source. With the first radiation source as the origin of the coordinate system, establish a first geometric scene with uniform air density distribution. Set up multiple concentric spheres with different radii and use the surface of each concentric sphere as a detection surface. The radiation source in the environment affected by the shock wave is recorded as the second radiation source. The first radiation source is the same as the second radiation source, and its energy spectrum is the energy spectrum of slow-emitted neutrons or gamma rays from fission.

[0008] Step 2: Simulate the transport process of slow-emitted neutrons or gamma rays from fission, record the first particle fluence or dose on each of the detection surfaces, obtain the first air mass thickness between each detection surface and the first radiation source, and construct the mapping relationship between each first air mass thickness and the corresponding first particle fluence or dose.

[0009] Step 3: In the environment affected by the shock wave, establish a second geometric scene with non-uniform air density distribution, select a target detection point in the second geometric scene; calculate the air density distribution within a preset range from the second radiation source, and calculate the second air mass thickness between the second radiation source and the target detection point at different time periods based on the air density distribution;

[0010] Step 4: Calculate the first particle flux rate or dose rate corresponding to the mapping relationship obtained in step 2 for the second air mass thickness;

[0011] Step 5: Based on the functional relationship between radiation source intensity and time, obtain the radiation source intensity of the second radiation source corresponding to the different time periods, and multiply each radiation source intensity by the corresponding first particle fluence rate or dose rate to obtain the second particle fluence rate or dose rate.

[0012] Step 6: Integrate the second particle fluence rate or dose rate over time to obtain the particle fluence or dose corresponding to the target detection point, thus completing the rapid calculation of the fission slow-emission nuclear radiation fluence or dose under the influence of the shock wave.

[0013] Further, step 1 specifically involves setting up a first radiation source, establishing a first geometric scene with uniform air density distribution using the first radiation source as the origin of the coordinate system, and setting up n geometric scenes from the inside out with radii r1, r2...r... n The concentric spheres are used as detection surfaces, where n≥50; the radiation source in the environment affected by the shock wave is denoted as the second radiation source, and the first radiation source is the same as the second radiation source, whose energy spectrum is the energy spectrum of slow-emitted neutrons or gamma rays from fission.

[0014] Further, step 2 specifically involves simulating the transport process of slow-emitted neutrons or gamma rays from fission using the Monte Carlo method, and recording the first particle fluence or dose D on each detection surface. 01 D 02 ...D 0n Obtain the first air mass thickness MT1, MT2...MT between each detection surface and the first radiation source. n Construct the first air mass thicknesses MT1, MT2...MT n With the corresponding first particle dose or dosage D 01 D 02 ...D 0n The mapping relationship between them.

[0015] Further, step 3 specifically involves establishing a second geometric scene with non-uniform air density distribution in the shock wave environment containing the second radiation source, selecting a target detection point within the second geometric scene, calculating the air density distribution within a preset range from the second radiation source using the shock wave reflection flow field theory method, and calculating the time intervals t1, t2...t between the second radiation source and the target detection point based on this air density distribution. m Second air mass thickness MT t1 MT t2 ……MT tm , m≥50.

[0016] Further, step 4 specifically involves calculating the second air mass thickness MT using an interpolation algorithm. t1 MT t2 ……MT tm The first particle fluence rate or dose rate D corresponding to the mapping relationship obtained in step 2 t1 D t2 …D tm .

[0017] Furthermore, step 5 specifically includes:

[0018] 5.1. Based on the functional relationship between radiation source intensity and time, obtain the values ​​corresponding to the time intervals t1, t2, ... t... m The intensity of the corresponding second radiation source is compared with the first particle fluence rate or dose rate D. t1 D t2 ...D tm By multiplying the corresponding values, we obtain the second particle fluence rate or dose rate D. T1 D T2 …D Tm ;

[0019] 5.2. For each second particle infusion rate or dose rate D... T1 D T2 …D Tm Perform geometric corrections to obtain the corrected second particle fluence rate or dose rate D. TF1 D TF2 …D TFm ;

[0020] Step 6 specifically involves adjusting the corrected second particle dose rate or dosage rate D. TF1 D TF2 …D TFm By performing time integration, the particle fluence or dose corresponding to the target detection point is obtained, thus completing the rapid calculation of the slow-release nuclear radiation fluence or dose under the influence of the shock wave.

[0021] Further, step 5.2 specifically involves applying the following formula to each second particle infusion rate or dose rate D. T1 D T2 …D Tm Perform geometric corrections to obtain the corrected second particle fluence rate or dose rate D. TF1 D TF2 …D TFm :

[0022]

[0023] in, ρ is the uniform air density corresponding to the first geometric scene, and R is the distance between the target detection point and the second radiation source.

[0024] Furthermore, in step 3, the preset range is within 3000m of the second radiation source.

[0025] Furthermore, in step 2, the first air mass thickness MT1, MT2...MT n Calculate using the following formula:

[0026] MT j =∫ρ1(r)dr

[0027] Where j = 1, 2, ..., n, ρ1(r) is the air density at a distance r from the first radiation source, and the integration interval is from the first radiation source to a radius of r. j The detection surface;

[0028] In step 3, the second air mass thickness MT t1 MT t2 ……MT tm Calculate using the following formula:

[0029] MT ti =∫ρ ti (r)dr

[0030] Where, ρ ti (r) represents the distance r from the second radiation source, t i The air density corresponding to the time period, with the integration interval from the second radiation source to the target detection point.

[0031] Furthermore, in step 3, the target detection point is selected at a distance of 0.5-1.5m from the ground.

[0032] The beneficial effects of this invention are:

[0033] 1. The present invention provides a rapid calculation method for the flux or dose of slow-release fission nuclear radiation under the influence of shock waves. It takes into account the complex distribution of air density under shock wave disturbance, so that the method can be used to calculate the slow-release fission nuclear radiation environment under the influence of shock waves, and can provide support for the assessment of nuclear radiation environment in specific scenarios and the design of nuclear radiation shielding for personnel and equipment.

[0034] 2. The present invention provides a rapid calculation method for the fission slow-emission nuclear radiation flux or dose under the influence of shock waves. The calculation is based on the mapping relationship between air mass thickness and nuclear radiation flux or dose. Compared with the traditional Monte Carlo method simulation, the calculation time is significantly reduced, and the calculation speed is effectively improved. Attached Figure Description

[0035] Figure 1 This is a flowchart of an embodiment of a method for rapidly calculating the fission slow-emission nuclear radiation flux or dose under the influence of a shock wave according to the present invention;

[0036] Figure 2 This is an embodiment of the present invention. 235 U fission delayed gamma-ray energy spectrum;

[0037] Figure 3 This is an embodiment of the present invention. 235 U fission delayed gamma-ray time spectrum;

[0038] Figure 4 It is calculated in the embodiments of the present invention. 235 U fission delayed gamma ray dose distribution map. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] This invention provides a method for rapidly calculating the slow-release nuclear radiation fluence or dose under the influence of a shock wave, such as... Figure 1 As shown, the method includes the following steps:

[0041] Step 1: Set up the first radiation source and establish a uniform air density distribution with the first radiation source as the origin (air density is taken as 0.001 g / cm³). 3 The first geometric scene is set with n elements from the inside out, with radii r1, r2...r... nThe concentric spheres, each with its own surface serving as a detection surface; the first radiation source is the same as the second radiation source in the shock wave-affected environment, and its energy spectrum is that of slow-emitted fission neutrons or gamma rays; n≥50, in this embodiment, n=100; furthermore, as Figure 2 As shown, 235 The energy spectra of slow-emitted gamma rays from U fission at different times do not differ significantly. Therefore, the energy spectrum of 0.2–0.5 s is used to represent the energy spectrum of any arbitrary time period; thus, the energy spectra of both the first and second radiation sources are within the range of 0.2–0.5 s. 235 U fission delayed gamma-ray energy spectrum.

[0042] Step 2: Simulate the transport process of slow-emitted neutrons or gamma rays from fission using the Monte Carlo method, and record the first particle fluence or dose D on each detector surface. 01 D 02 ...D 0n Obtain the first air mass thickness MT1, MT2...MT between each detection surface and the first radiation source. n Construct the first air mass thicknesses MT1, MT2...MT n With the corresponding first particle dose or dosage D 01 D 02 ...D 0n The mapping relationship between them.

[0043] Among them, the first air mass thicknesses MT1, MT2...MT n Calculate using the following formula:

[0044] MT j =∫ρ1(r)dr

[0045] Where j = 1, 2, ..., n, ρ1(r) is the air density at a distance r from the first radiation source, and the integration interval is from the first radiation source to a radius of r. j The detection surface;

[0046] Step 3: In the shock wave environment containing the second radiation source, establish a second geometric scene with non-uniform air density distribution, and select a target detection point in the second geometric scene; calculate the air density distribution within a preset range from the second radiation source using the shock wave reflection flow field theory method, and calculate the time intervals t1, t2...t between the second radiation source and the target detection point based on this air density distribution. m Second air mass thickness MT t1 MT t2 ……MT tm m≥50. In this embodiment, m=100, and the preset range is within 3000m of the second radiation source; in addition, the target detection position can be selected at a distance of 0.5-1.5m from the ground, and in this embodiment, a distance of 1m from the ground is selected;

[0047] Among them, the second air mass thickness MT t1 MT t2 ……MT tm Calculate using the following formula:

[0048] MT ti =∫ρ ti (r)dr

[0049] Where i = 1, 2…m, ρ ti (r) represents the distance r from the second radiation source, t i The air density corresponding to the time period, with the integration interval from the second radiation source to the target detection point.

[0050] Step 4: Calculate the second air mass thickness MT using an interpolation algorithm. t1 MT t2 ……MT tm The first particle fluence rate or dose rate D corresponding to the above mapping relationship t1 D t2 …D tm .

[0051] Step 5, based on 235 U fission delayed gamma-ray time spectrum as follows Figure 3 As shown in the figure, the intensity of the radiation source varies at different time periods. Based on the functional relationship between the radiation source intensity and time, the values ​​of t1, t2, ..., t3 are obtained. m corresponding 235 The intensity of the U fission delayed gamma-ray radiation source, respectively, is compared with the first particle fluence rate or dose rate D. t1 D t2 ...D tm By multiplying the corresponding values, we obtain the second particle fluence rate or dose rate D. T1 D T2 …D Tm Then, the dosage rate or dose rate D of each second particle is calculated using the following formula. T1 D T2 …D Tm Perform geometric corrections to obtain the corrected second particle fluence rate or dose rate D. TF1 D TF2 …D TFm :

[0052]

[0053] in, ρ is the uniform air density corresponding to the first geometric scene, and R is the distance between the target detection point and the second radiation source.

[0054] Step 6: Adjust the corrected second particle dose rate or dose rate D. TF1 D TF2 …D TFm Integrating over time, it is approximately equal to the second particle dose rate or dose rate D obtained in step 5. TF1 D TF2 …D TFm Multiplying by the time interval and summing the results, we obtain the particle fluence or dose corresponding to the above target detection point:

[0055] D TF1 ×(t2-t1)+D TF2 ×(t3-t2)+…+D TFm ×(t m+1 -t m )

[0056] The above steps are used to calculate the second radiation source and target detection point at different heights above the ground. 235 U fission delayed gamma ray fluence or dose distribution such as Figure 4 As shown, each line in the figure represents an isodose curve, and the dose values ​​are marked on the figure. The dose unit is rad, and the shock wave source intensity is equivalent to 10,000 tons of TNT.

[0057] Actual calculation results show that the technical solution of this embodiment effectively solves the problem of rapid calculation of fission delayed gamma ray flux or dose under the influence of shock wave. The calculation time is short, the process is simple and clear, easy to implement, the physical image is clear, and it has strong versatility.

[0058] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A rapid calculation method for the slow-release nuclear radiation flux or dose under the influence of a shock wave, characterized in that, Includes the following steps: Step 1: Set up the first radiation source. With the first radiation source as the origin of the coordinate system, establish a first geometric scene with uniform air density distribution. Set up multiple concentric spheres with different radii and use the surface of each concentric sphere as a detection surface. The radiation source in the environment affected by the shock wave is recorded as the second radiation source. The first radiation source is the same as the second radiation source, and its energy spectrum is the energy spectrum of slow-emitted neutrons or gamma rays from fission. Step 2: Simulate the transport process of slow-emitted neutrons or gamma rays from fission, record the first particle fluence or dose on each of the detection surfaces, obtain the first air mass thickness between each detection surface and the first radiation source, and construct the mapping relationship between each first air mass thickness and the corresponding first particle fluence or dose. Step 3: In the environment affected by the shock wave, establish a second geometric scene with non-uniform air density distribution, select a target detection point in the second geometric scene; calculate the air density distribution within a preset range from the second radiation source, and calculate the second air mass thickness between the second radiation source and the target detection point at different time periods based on the air density distribution; Step 4: Calculate the first particle flux rate or dose rate corresponding to the mapping relationship obtained in step 2 for the second air mass thickness; Step 5: Based on the functional relationship between radiation source intensity and time, obtain the radiation source intensity of the second radiation source corresponding to the different time periods, and multiply each radiation source intensity by the corresponding first particle fluence rate or dose rate to obtain the second particle fluence rate or dose rate. Step 6: Integrate the second particle fluence rate or dose rate over time to obtain the particle fluence or dose corresponding to the target detection point, thus completing the rapid calculation of the fission slow-emission nuclear radiation fluence or dose under the influence of the shock wave.

2. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 1, characterized in that: Step 1 specifically involves setting up a first radiation source, establishing a first geometric scene with uniform air density distribution using the first radiation source as the origin, and setting up n geometric scenes from the inside out with radii r1, r2...r... n The concentric spheres are used as detection surfaces, where n≥50; the radiation source in the environment affected by the shock wave is denoted as the second radiation source, and the first radiation source is the same as the second radiation source, whose energy spectrum is the energy spectrum of slow-emitted neutrons or gamma rays from fission.

3. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 2, characterized in that: Step 2 specifically involves simulating the transport process of slow-emitted neutrons or gamma rays from fission using the Monte Carlo method, and recording the first particle fluence or dose D on each detector surface. 01 D 02 ...D 0n Obtain the first air mass thickness MT1, MT2...MT between each detection surface and the first radiation source. n Construct the first air mass thicknesses MT1, MT2...MT n With the corresponding first particle dose or dosage D 01 D 02 ...D 0n The mapping relationship between them.

4. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 3, characterized in that: Step 3 specifically involves establishing a second geometric scene with non-uniform air density distribution within the shock wave environment containing the second radiation source, selecting a target detection point within the second geometric scene, calculating the air density distribution within a preset range from the second radiation source using the shock wave reflection flow field theory method, and calculating the time intervals t1, t2...t between the second radiation source and the target detection point based on this air density distribution. m Second air mass thickness MT t1 MT t2 ……MT tm , m≥50.

5. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 6, characterized in that: Step 4 specifically involves calculating the second air mass thickness MT using an interpolation algorithm. t1 MT t2 ……MT tm The first particle fluence rate or dose rate D corresponding to the mapping relationship obtained in step 2 t1 D t2 …D tm .

6. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 5, characterized in that: Step 5 specifically includes: 5.

1. Based on the functional relationship between radiation source intensity and time, obtain the values ​​corresponding to the time intervals t1, t2, ... t... m The intensity of the corresponding second radiation source is compared with the first particle fluence rate or dose rate D. t1 D t2 ...D tm By multiplying the corresponding values, we obtain the second particle fluence rate or dose rate D. T1 D T2 …D Tm ; 5.

2. For each second particle infusion rate or dose rate D... T1 D T2 …D Tm Perform geometric corrections to obtain the corrected second particle fluence rate or dose rate D. TF1 D TF2 …D TFm ; Step 6 specifically involves adjusting the corrected second particle dose rate or dosage rate D. TF1 D TF2 …D TFm By performing time integration, the particle fluence or dose corresponding to the target detection point is obtained, thus completing the rapid calculation of the slow-release nuclear radiation fluence or dose under the influence of the shock wave.

7. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 6, characterized in that: Step 5.2 specifically involves applying the following formula to each second particle infusion rate or dose rate D. T1 D T2 …D Tm Perform geometric corrections to obtain the corrected second particle fluence rate or dose rate D. TF1 D TF2 …D TFm : in, ρ is the uniform air density corresponding to the first geometric scene, and R is the distance between the target detection point and the second radiation source.

8. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 7, characterized in that: In step 3, the preset range is within 3000m of the second radiation source.

9. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 8, characterized in that: In step 2, the first air mass thickness MT1, MT2...MT n Calculate using the following formula: MT j =∫ρ1(r)dr Where j = 1, 2, ..., n, ρ1(r) is the air density at a distance r from the first radiation source, and the integration interval is from the first radiation source to a radius of r. j The detection surface; In step 3, the second air mass thickness MT t1 MT t2 ……MT tm Calculate using the following formula: MT ti =∫ρ ti (r)dr Where, ρ ti (r) represents the distance r from the second radiation source, t i The air density corresponding to the time period, with the integration interval from the second radiation source to the target detection point.

10. The rapid calculation method for fission-induced slow-release nuclear radiation flux or dose under the influence of a shock wave according to claim 9, characterized in that: In step 3, the target detection point is selected at a distance of 0.5-1.5m from the ground.

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