Construction method for dynamic transfer model of fish to radionuclide concentration

Abstract

The invention discloses a construction method of a fish-to-radionuclide concentration dynamic transfer model, and the method comprises the following steps: building a water body-fish two-chamber model, and obtaining a differential equation for describing the dynamic transfer of radionuclides in a water body and a fish body in a concentration process; transforming the differential equation to obtain a parameter equation that the radionuclide specific activity in the fish body library changes along with time; aiming at the obtained parameter equation, setting a fish body nuclide concentration coefficient, an uptake half-life period and a water body density in an equilibrium state, and combining an initial condition that the initial specific activity is 0 to obtain an equation set and carrying out simultaneous solution; the dynamic transfer model of the radionuclide in the fish body in the concentration process is obtained by substituting the water body density, the specific activity of the radionuclide in the water body, the nuclide concentration coefficient of the fish body and the specific numerical value of the uptake half-life period into a formula, and the dynamic transfer model of the radionuclide in the fish body in the final concentration process is obtained. By means of the method, the dynamic transfer behavior of fishes to radionuclides in water can be simulated, the dynamic transfer rule of fishes to radionuclides is explored, and therefore the influence of nuclear power liquid effluent discharge on the water environment is further evaluated.

Description

Technical Field

[0001] This invention relates to the field of environmental impact assessment technology for nuclear facilities, and in particular to a method for constructing a dynamic transfer model of radionuclide concentration in fish. Background Technology

[0002] Nuclear energy is economical and efficient, making it an ideal clean energy source that has fueled rapid economic development. However, while creating economic value, nuclear power also releases liquid effluents containing radioactive nuclides into nearby waters, potentially impacting the aquatic environment and marine life. Studies have shown that fish, as a key link in the aquatic food chain, can accumulate radioactive nuclides through direct contact with water or ingestion, posing a potential threat to human health through biomagnification.

[0003] In existing technologies, to study the dynamic transfer and concentration patterns of radionuclides in aquatic ecosystems and assess the impact of radionuclide liquid effluent discharges on fish in the aquatic environment, patent publication number CN113609654A describes a method and system for estimating the concentration coefficient of radionuclides in water equilibrium by fish. Based on the living characteristics of fish and the accumulation characteristics of radionuclides within organisms, this method divides different tissues of fish into fast and slow phases according to the different rates of radionuclide transfer and accumulation, establishing a dynamic transfer model of radionuclides between the fish body and the aquatic environment. However, this method is only applicable to studying the dynamic transfer and concentration of radionuclides in larger fish that can clearly distinguish between different tissues and the fast and slow phases. It is not applicable to smaller fish that cannot distinguish between different tissues and the fast and slow phases. Furthermore, this model requires obtaining the transfer parameters of radionuclides in different tissues of fish; however, research on transfer parameters is relatively limited both domestically and internationally, and data is scarce, resulting in poor practicality of the method. Therefore, further exploration and research on the dynamic transfer and concentration processes of radionuclides are lacking in this field. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for constructing a dynamic transfer model of radionuclide concentration in fish. This method can simulate the dynamic transfer behavior of radionuclides in water by fish, explore the dynamic transfer law of radionuclides in fish, and thus further evaluate the impact of nuclear power plant liquid effluent discharge on the aquatic environment.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for constructing a dynamic transfer model of radionuclide concentration in fish, characterized by comprising the following steps: A two-compartment model of water and fish was established, and differential equations describing the dynamic transfer of radionuclides in the water and fish during the concentration process were obtained. Assuming that the specific activity of radionuclides in the water reservoir does not change with time, the above differential equation is transformed to obtain the parametric equation for the change of the specific activity of radionuclides in the fish reservoir with time. Regarding the parametric equation, let the nuclide concentration coefficient of the fish body in equilibrium be... The uptake half-life is The density of the water is By combining the initial condition of zero initial specific activity, a set of equations was obtained and solved simultaneously to obtain a dynamic transfer model of radionuclides in fish during the concentration process. water density Specific activity of radionuclides in water Fish body nuclide concentration coefficient and uptake half-life The specific values ​​are substituted into the dynamic transfer model of the radionuclide in the fish body to obtain the corresponding dynamic transfer model relationship of the concentration of radionuclide in fish.

[0006] Furthermore, the dynamic transfer model of radionuclides within the fish during the concentration process is as follows: (1) In the formula, C 1( t ( ) represents the time of radioactive nuclides in the fish storage room t Specific activity, Bq / kg Specific activity of radionuclides in a water reservoir, in Bq / kg.

[0007] Furthermore, the differential equation for the dynamic transfer is: (2) In the formula, The radioactive decay constant is 1 / d; C 0( t )and C 1( t ( ) represent the time-related radionuclides in the water and fish tank, respectively. t Specific activity, Bq / kg; k 01 and k 10 1 / d represents the migration rate constant of radionuclides from the water reservoir to the fish reservoir, and from the fish reservoir to the water reservoir, respectively.

[0008] Furthermore, the parametric equation is as follows: (3) In the formula, K Let be any non-zero constant.

[0009] Furthermore, the specific activity of radionuclides in the water reservoir did not change over time. constant .

[0010] Furthermore, the system of equations is as follows: .

[0011] Furthermore, the fish in question is a zebrafish.

[0012] Furthermore, the radioactive nuclide is 137 Cs.

[0013] Furthermore, the concentration process of the radionuclide takes at least 58 days.

[0014] Furthermore, the average value of the specific activity of radionuclides in the fish over several days was selected as the nuclide concentration in the fish at equilibrium.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This method constructs a dynamic transfer model of radionuclide concentration in fish. It is established by combining the characteristics of radionuclide accumulation and decay in fish. It focuses on the concentration and excretion of radionuclide in fish and no longer depends on the acquisition of transfer parameters.

[0016] This method provides a new approach for studying the dynamic accumulation and transfer of radionuclides in small fish, where it is difficult to distinguish between different tissue sites and the fast and slow phases of radionuclide accumulation. This offers a valuable reference for further understanding the accumulation patterns of radionuclides in fish and for subsequently assessing the impact of liquid radionuclide effluent discharges on fish and the aquatic environment. Attached Figure Description

[0017] Figure 1 This is a block diagram of a reservoir model established for the dynamic transfer process of radionuclides between water and fish in an embodiment of the present invention. Figure 2 The zebrafish body obtained during the concentration process in the embodiments of the present invention 137 A comparison chart of measured and calculated Cs specific activity values. Detailed Implementation

[0018] To enhance understanding of the present invention, we will now describe it in further detail with reference to the accompanying drawings. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0019] To study the dynamic transfer patterns of radionuclide concentration in aquatic ecosystems and assess the impact of radionuclide liquid effluent discharge on fish in the aquatic environment, a model for the dynamic transfer of radionuclide concentration in fish can be established.

[0020] A specific embodiment of a method for constructing a dynamic transfer model of radionuclide concentration in fish is provided. In this embodiment, wild-type AB strain zebrafish is used as the research object, and the method includes the following specific steps: S1: Establish as follows Figure 1 The water-zebrafish two-compartment model is shown, and a systematic analysis method is used to analyze it, resulting in a description of the radionuclide concentration process. 137 The differential equation for the dynamic transfer of Cs in water and zebrafish is as follows: (2) In the formula, The radioactive decay constant is 1 / d; C 0( t )and C 1( t ( ) are radionuclides in water and zebrafish reservoirs, respectively. 137 Cs in time t Specific activity, Bq / kg; k 01 and k 10 They are radioactive nuclides 137 Cs is the migration rate constant from the water reservoir to the zebrafish reservoir, and from the zebrafish reservoir to the water reservoir, 1 / d.

[0021] S2.1: Due to radioactive nuclides in the water reservoir 137 Cs specific activity does not change significantly over time. Can be converted to a constant .make , Equation (2) can be simplified to: (4) S2.2: After several transformations of equation (4), we get the following: (6) (7) According to the relevant theory of integrals, we can obtain from equation (7): (8) In the formula, C It is an arbitrary constant.

[0022] Equation (8) can be further transformed sequentially to obtain: (9) (10) Simplifying equation (10) yields: (5) In the formula, K Let be any non-zero constant.

[0023] S2.3: Will , Substituting back into equation (5), we obtain the radionuclides found in zebrafish. 137 The parametric equation for the change of Cs specific activity over time is shown below: (3) S3: Regarding the parametric equation (3) obtained in S2, let the CF value (fish body nuclide concentration coefficient) in equilibrium be... The uptake half-life is The density of the water is Combining this with the initial condition of zero specific activity, we can obtain the following system of equations: Solving the above system of equations yields the results of the radionuclide concentration process. 137 The dynamic transfer model of Cs in zebrafish is as follows: (1) S4: Water density Radionuclides in water 137 Cs specific activity and zebrafish's reaction to radionuclides 137 Cs Value and uptake half-life Substituting the specific data into equation (1) yields the radionuclides obtained during the final concentration process. 137 A dynamic transfer model of Cs in zebrafish.

[0024] The dynamic transfer model constructed by this method divides the system or object under study into several interconnected chambers, each representing a specific part of the system, and describes the dynamic behavior of the system through the flow and exchange of matter between these chambers.

[0025] The model of radionuclide migration between water and fish can be viewed as a combination of a water reservoir and a fish reservoir with certain boundary spaces. Radionuclides can migrate and mix freely between the reservoirs, and the transfer rate of radionuclides can be characterized by specific rate constants or transfer coefficients, thereby enabling the analysis of the entire system.

[0026] To verify the effectiveness of the model, the following comparative experiments were conducted.

[0027] zebrafish 137 Taking the construction of a dynamic transfer model for Cs concentration as an example, the experiment used wild-type AB strain zebrafish as the research subject. During the concentration experiment, the radionuclide concentration in the water was maintained at a certain level. 137 The activity of Cs remains constant.

[0028] The concentration experiment was conducted over 58 days, with samples taken on days 1, 2, 5, 10, 15, 20, 25, 30, 45, 50, 51, and 58 for in vivo measurements. The concentration in zebrafish was then... 137 After the Cs nuclide level remained basically stable, the concentration experiment was terminated, and the experimental results were as follows: Figure 2 The measured values ​​are shown in the figure.

[0029] The fish's body on days 50, 51, and 58 137 The average Cs specific activity was used as the nuclide concentration of the organism in equilibrium, and the corresponding number of days in the water body was used as the concentration of the nuclide. 137 The average Cs activity was used as the nuclide activity concentration in the water at equilibrium. The equilibrium concentration of radionuclides in zebrafish was then calculated. 137 Cs's CF value .

[0030] In addition, water density Radionuclides in water 137 Cs specific activity and uptake half-life The possible values ​​are as follows: 1kg / L =1000Bq / L, =5.81 Bq / L, =30d, substituting into equation (1), we obtain the dynamic transfer model: The zebrafish obtained during the concentration process in the above embodiments 137 The calculated values ​​of Cs specific activity from the model were compared with the experimentally measured values, such as... Figure 2 As shown.

[0031] As can be seen from the figure, the calculated and experimental values ​​of the dynamic transfer model established by this method are in relatively good agreement, especially in the early stage of the experiment when the concentration period is less than 40 days. The results obtained using this method in zebrafish are particularly good. 137The calculated Cs specific activity values ​​from the model approximate the measured values, demonstrating the effectiveness of this method. Therefore, this method is highly practical and provides a new approach for studying the dynamic accumulation and transfer of radionuclides in small fish, where it is difficult to distinguish between different tissue sites and the fast and slow phases.

[0032] The above specific embodiments are only for illustrating the technical concept and structural features of the present invention, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit and essence of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for constructing a dynamic transfer model of radionuclide concentration in fish, characterized in that, Includes the following steps: A two-compartment model of water and fish was established, and differential equations describing the dynamic transfer of radionuclides in the water and fish during the concentration process were obtained. Assuming that the specific activity of radionuclides in the water reservoir does not change with time, the above differential equation is transformed to obtain the parametric equation for the change of the specific activity of radionuclides in the fish reservoir with time. Regarding the parametric equation, let the nuclide concentration coefficient of the fish body in equilibrium be... The uptake half-life is The density of the water is By combining the initial condition of zero initial specific activity, a set of equations was obtained and solved simultaneously to obtain a dynamic transfer model of radionuclides in fish during the concentration process. water density Specific activity of radionuclides in water Fish body nuclide concentration coefficient and uptake half-life The specific values ​​are substituted into the dynamic transfer model of the radionuclide in the fish body to obtain the corresponding dynamic transfer model relationship of the concentration of radionuclide in fish.

2. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 1, characterized in that: The dynamic transfer model of radionuclides within the fish during the concentration process is as follows: （1） In the formula, C 1( t ( ) represents the time of radioactive nuclides in the fish storage room t Specific activity, Bq / kg Specific activity of radionuclides in a water reservoir, in Bq / kg.

3. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 2, characterized in that: The differential equation for the dynamic transfer is: （2） In the formula, The radioactive decay constant is 1 / d; C 0( t )and C 1( t ( ) represent the time-related radionuclides in the water and fish tank, respectively. t Specific activity, Bq / kg; k 01 and k 10 1 / d represents the migration rate constant of radionuclides from the water reservoir to the fish reservoir, and from the fish reservoir to the water reservoir, respectively.

4. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 3, characterized in that: The parametric equation is as follows: （3） In the formula, K Let be any non-zero constant.

5. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 4, characterized in that: The specific activity of radionuclides in the water reservoir does not change over time. constant .

6. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 5, characterized in that: The system of equations is 。 7. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 1, characterized in that: The fish in question is a zebrafish.

8. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 1, characterized in that: The radioactive nuclide is 137 Cs.

9. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 8, characterized in that: The concentration process of the radionuclide takes at least 58 days.

10. The method for constructing a dynamic transfer model of radionuclide concentration in fish according to claim 1, characterized in that: The average value of the specific activity of radionuclides in fish over several days was selected as the nuclide concentration in fish at equilibrium.

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