Radionuclide aquatic organism ecological transfer simulation experiment device and method

Abstract

The invention relates to a radionuclide aquatic organism ecological transfer simulation experiment device which comprises a glass aquarium, a filtering water tank, a water body circulating pump, an air blowing pump and an ultraviolet lamp, the glass aquarium is used for constructing an aquatic ecological environment, a filtering material is arranged in the filtering water tank, and the water body circulating pump is connected with the air blowing pump. The water circulating pump is communicated with the filtering water tank and the glass aquarium and used for enabling water in the glass aquarium to circularly pass through the filtering water tank and then return into the glass aquarium. The invention further relates to a radionuclide aquatic organism ecological transfer simulation experiment method. By adopting the radionuclide aquatic organism ecological transfer simulation experiment device and the radionuclide aquatic organism ecological transfer simulation experiment method, an aquatic ecology simulation experiment can be smoothly carried out, the filter material has no adsorption loss on nuclides, the water quality of a water body is ensured to reach the standard, and the device and the method can be used for simulating a river / ocean water ecosystem and researching a transfer and transformation mechanism of various nuclides in aquatic organisms. And the internal irradiation dose estimation accuracy of nuclear facility environment evaluation is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear facility environmental impact assessment, and in particular relates to a radionuclide aquatic biological ecological transfer simulation experimental device and method. Background Art

[0002] Liquid effluents from nuclear facility operations are an important component of radioactive effluents. Liquid effluents are discharged into surface waters such as rivers and oceans. Radioactive nuclides may be transferred to aquatic organisms and enter the human food chain through various pathways, becoming an important source of public internal exposure dose estimation. With the development of the times, it is necessary to accurately evaluate the safety impact of radioactive effluents on the public and the environment, conduct in-depth research on the transfer law of radioactive nuclides from water bodies to aquatic organisms, obtain the relevant transfer coefficients of nuclides in aquatic organisms, and establish experimental simulation methods for the transfer of nuclides in aquatic organisms.

[0003] The General Provisions on Nuclear Radiation Environmental Quality Assessment clearly state that: Based on the aquatic biological resources in local waters and in combination with the exposure pathway, appropriate calculation models, bioconcentration factors and related parameters should be selected to estimate the concentration and radiation dose of important radionuclides in aquatic animals and plants in the wastewater receiving waters. The Regulations on Environmental Radiation Protection of Nuclear Power Plants require that: When evaluating the suitability of a nuclear power plant site, the impact of the nuclear power plant's radioactive effluent emissions (especially effluent emissions under accident conditions), thermal emissions and chemical effluent emissions on the environment, local ecosystems and the public must be fully demonstrated. This shows that the study of the transfer of radionuclides in liquid effluents to aquatic organisms is an important part of nuclear environmental science, involving research on nuclide transfer parameters and public dose estimation.

[0004] Aquatic biological experimental devices can be used to simulate the transfer and concentration process of liquid effluent from nuclear facilities in freshwater / seawater aquatic ecosystems, such as the transfer scenario of nuclides in water-aquatic biological systems, to obtain the transfer parameters of nuclides in aquatic organisms. Aquatic biological experimental devices are essential facilities for studying water ecological radiology. Generally speaking, the filter materials of popular aquatic biological experimental devices on the market include activated carbon, which will strongly adsorb radionuclides and may not meet the requirements of radiological ecological simulation experiments.

[0005] According to IAEA Technical Report No. 472 (IAEA. Handbook of parameter values ​​for the parameter values ​​for the prediction of radionuclide transfer in terrestrial and freshwater environments. IAEA technical reports series NO. 472, 2010), concentration ratios (CR) are used to characterize the absorption capacity of aquatic organisms in freshwater for radionuclides at different times. The concentration ratio calculation formula is as follows:

[0006]

[0007] IAEA Technical Report No. 472 gives recommended values ​​for concentration ratios of freshwater invertebrates and freshwater fish, which are suitable for evaluations without specific site conditions. When conducting environmental impact assessments of nuclear facilities, it is recommended to use transfer parameters with site characteristics and specific organisms. Ecological transfer parameters are important data for nuclear environmental assessments. It is urgent to conduct in-depth research on the migration of radionuclides in aquatic organisms, obtain ecological transfer parameters that meet the characteristics of my country's nuclear facilities according to the types of aquatic organisms and nuclear facility emissions in my country, and establish relevant simulation experimental method processes. Summary of the invention

[0008] In view of the defects existing in the prior art, the purpose of the present invention is to provide a radionuclide aquatic biological ecological transfer simulation experimental device and method, so as to conduct research on the radionuclide ecological transfer in aquatic organisms.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is: a radioactive nuclide aquatic biological ecological transfer simulation experimental device, including: a glass aquarium, a filter water tank, a water circulation pump, an air pump and an ultraviolet lamp, the glass aquarium is used to construct an aquatic ecological environment, the filter water tank is provided with a filter material, the water circulation pump is connected to the filter water tank and the glass aquarium respectively, and is used to circulate the water in the glass aquarium through the filter water tank and then return to the glass aquarium, the air pump is used to blow air into the water body, and the ultraviolet lamp is used to sterilize the water body.

[0010] Furthermore, there are multiple filter water tanks, which are connected in sequence, and the water circulation pump is connected to the first filter water tank and the glass aquarium respectively, and the last filter water tank is connected to the glass aquarium.

[0011] Furthermore, the number of the filtering water tanks is three.

[0012] Furthermore, the filter material in the filter tank is five layers.

[0013] Furthermore, the five layers of filter materials are arranged from bottom to top as follows: first layer: ceramic rings, bio-balls; second layer: filter cotton; third layer: ceramic rings, bio-balls; fourth layer: filter cotton; fifth layer: ceramic rings.

[0014] Furthermore, the filter water tank is arranged at one end of the glass aquarium away from the ground.

[0015] Furthermore, the dimensions of the filtering water tank are: 90 cm long×20 cm wide×20 cm high.

[0016] Furthermore, the dimensions of the glass aquarium are: length 146 cm×width 58 cm×height 71 cm, and a volume of 600 L.

[0017] Furthermore, the water circulation pump: 60w, is placed in the water body, the air pump is placed outside the glass aquarium, and the ultraviolet lamp: 3W, is equipped with a sunshade.

[0018] The present invention also provides a radionuclide aquatic biological ecological transfer simulation experimental method, comprising the steps of: determining experimental parameters according to research needs; establishing an aquatic ecological environment; starting water circulation after introducing radionuclides, and adding aquatic organisms to conduct experiments.

[0019] The effect of the present invention is that: the aquatic ecological simulation experiment can be smoothly carried out, the filter material has no adsorption loss of nuclides, the water quality of the water body is ensured to meet the standard, and the normal survival of aquatic organisms is guaranteed. A simulation experiment process method for the ecological transfer of radioactive nuclides in aquatic organisms is proposed, representative aquatic organisms are selected as experimental objects according to the research objectives, experimental parameters are determined, key nuclides are added to the aquarium water body, and ecological transfer simulation experiments of nuclides in different growth periods of aquatic organisms are carried out. It can be used to simulate the water ecosystem of rivers / oceans, study the migration and transformation mechanism of multiple nuclides in aquatic organisms, obtain transfer parameters with site characteristics, improve the accuracy of internal exposure dose estimation in nuclear facility environmental assessment, and provide basic data for nuclear safety goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of a filter tank of a radionuclide aquatic biological ecological transfer simulation experimental device;

[0021] Figure 2 It is a schematic diagram of a method for simulating the ecological transfer of radionuclides in aquatic organisms;

[0022] Figure 3 The edible part of the crab 137 Cs, 90 Schematic diagram of the change of Sr concentration ratio;

[0023] Figure 4 It is in the chest carapace of adult crabs 137 Cs, 90 Schematic diagram of the change in Sr concentration ratio. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] like Figure 1 As shown, the present invention proposes a radioactive nuclide aquatic biological ecological transfer simulation experimental device, including a glass aquarium (not shown), a filter water tank, a water circulation pump (not shown), an air pump (not shown) and an ultraviolet lamp (not shown). The glass aquarium is used to construct an aquatic ecological environment. The filter water tank is provided with a filter material. The water circulation pump is connected to the filter water tank and the glass aquarium respectively, and is used to circulate the water in the glass aquarium through the filter water tank and then return to the glass aquarium. The air pump is used to blow air into the water body, and the ultraviolet lamp is used to sterilize the water body.

[0026] It can be understood that the filter material in the filter tank is used to circulate and filter the water flow in the glass aquarium to adsorb the nuclides in the water. In this embodiment, it is necessary to ensure that the filter material adsorbs less nuclides and does not cause the loss of radioactive nuclides, while ensuring the survival rate of aquatic organisms.

[0027] Furthermore, there are multiple filter water tanks, which are connected in sequence, and a water circulation pump is connected to the first filter water tank and the glass aquarium respectively, and the last filter water tank is connected to the glass aquarium.

[0028] It can be understood that by forming a circular filtration through multiple filter tanks connected in sequence, the effect of strong filtration can be increased. The flow direction of the circular filtration is: the water circulation pump draws the water in the glass aquarium into the first filter tank, and after being filtered by the filter material in the first filter tank, it flows to the next filter tank connected in sequence, until it flows to the last filter tank and is filtered by the filter material in the last filter tank, and then flows back into the glass aquarium to complete the circulation process.

[0029] Furthermore, the number of the filtering water tanks is three.

[0030] Furthermore, the filter material in the filter tank is five layers.

[0031] Furthermore, the five layers of filter materials are arranged from bottom to top as follows: first layer: ceramic rings, bio-balls; second layer: filter cotton; third layer: ceramic rings, bio-balls; fourth layer: filter cotton; fifth layer: ceramic rings.

[0032] Furthermore, the filter tank is arranged at one end of the glass aquarium away from the ground.

[0033] In this embodiment, the dimensions of the filter tank are: 90 cm long×20 cm wide×20 cm high.

[0034] It should be noted that the discharge of liquid effluent from nuclear facilities 90 Sr. 137 Cs has a long half-life and is closely related to the human food chain. It is a key nuclide in nuclear environmental assessment. In the selection of filter materials, stable elements Sr and Cs were used.

[0035] Selection of filter materials: Compare the adsorption of Sr and Cs in water by four filter materials: activated carbon, bio-balls, filter cotton and ceramic rings.

[0036] Quantitatively weigh SrCl2.6H2O and CsCl reagents to prepare solutions. The concentrations of Sr and Cs in the solutions are 4.90 mg / L and 8.86 mg / L, respectively. Add 7.4 g of filter cotton, 40.5 g of ceramic rings, 4 bio balls (33.6 g), and 67.0 g of activated carbon to four beakers (the volume of the four filter materials is the same), and add 2L of Sr and Cs solutions respectively. Stir with a glass rod to allow sufficient adsorption. Three days later, take water samples from the four beakers and measure the concentrations of Sr and Cs in the water. Use plasma emission spectrometry to determine the Sr concentration and atomic absorption spectrometry to determine the Cs concentration. Calculate the adsorption rates of Sr and Cs in water by the four filter materials: activated carbon, bio balls, ceramic rings, and filter cotton, see Table 1.

[0037]

[0038]

[0039] Table 1

[0040] Adsorption rate = (initial concentration - measured value) / initial concentration.

[0041] The adsorption capacity of the four adsorbent materials for Sr is: activated carbon > filter cotton > ceramic ring > bio ball, and the adsorption capacity of the four adsorbent materials for Cs is: activated carbon > ceramic ring > bio ball > filter cotton. Under the conditions of this experiment, the adsorption rates of activated carbon for Sr and Cs are 62.04% and 72.12% respectively, which is a strong adsorbent. In the aquatic biological experiment, activated carbon is not used. Three filter materials, filter cotton, ceramic ring and bio ball, will be used to filter water, which can not only ensure the survival rate of organisms, but also ensure the smooth progress of the experiment.

[0042] In this embodiment, the water circulation pump and the air pump are both electric submersible pumps, wherein the water circulation pump: 60w, with a thickened water pipe, is placed in the water body for water circulation. The air pump is placed outside the glass aquarium to blow air into the water body to increase oxygen. The ultraviolet lamp: 3W, with a light shield, is used for water sterilization.

[0043] In this embodiment, glass aquarium: according to the volume of the types of aquatic organisms studied, such as fish / shrimp / crab / shell, a glass aquarium is processed, which is 146cm long×58cm wide×71cm high and has a volume of 600L.

[0044] The radioactive nuclide aquatic organism ecological transfer simulation experimental device is easy and quick to use, ensuring that the filter material has less adsorption of nuclides and at the same time ensuring the survival rate of aquatic organisms.

[0045] like Figure 2 As shown, the present invention also provides a method for simulating the ecological transfer of radionuclides in aquatic organisms. According to the research objectives, representative aquatic organisms are selected as experimental subjects, key nuclides are added to the water in the glass aquarium, and a simulation experiment of the ecological transfer of nuclides in aquatic organisms at different growth stages is carried out. The method for simulating the ecological transfer of nuclides in aquatic organisms is clearly proposed, and the method comprises the following steps:

[0046] S1, determine the experimental parameters according to research requirements;

[0047] Specifically, according to the specific research objectives, experimental parameters such as aquatic organisms, water flow rate, water temperature, and radionuclide types are selected. At the same time, according to the biological concentration ratio and the detection limit of radionuclides in water, the radionuclide activity concentration in water is determined to minimize the radiation dose of workers.

[0048] S2, establish aquatic ecological environment;

[0049] Specifically, a radioactive aquatic organism ecological transfer experimental device is assembled. The experimental device is easy to use and ensures that the filter material has less adsorption of radionuclides while ensuring the survival rate of aquatic organisms.

[0050] S3, after the introduction of radionuclides, the water cycle was started and aquatic organisms were added for the experiment;

[0051] Specifically, radioactive nuclides are introduced into the aquarium water, and the circulating water flow mode is turned on with a water flow rate of 50L / min. Water oxygenation, circulating filtration, and ultraviolet light irradiation are carried out. After the water has circulated for one week, aquatic organisms are added for pollution experiments. At different pollution times, the organisms and supporting water are collected, pre-treated, analyzed and measured, and the concentration ratio of aquatic organisms to nuclides is obtained.

[0052] Let's take a specific example as an example:

[0053] Using the radioactive aquatic biological ecological transfer experimental device, freshwater adult crabs were purchased. Adult crabs: 6 kg, 2 autumns old, with an average weight of 98.7 g and an average length of 5.9 cm per adult crab.

[0054] conduct 90 Sr. 137 Determination method of Cs: 90 Sr determination instrument: low background α, β counting device, 137 Cs determination instrument: γ spectrometer.

[0055] Glass aquarium water: Radioactive nuclides are added to the water, and the solution 137 Cs radioactivity concentration 300Bq / L, in water 90 Sr radioactivity concentration is 300Bq / L.

[0056] Adult crab samples were collected at different times, and supporting water samples were collected separately. The sampling time of crab concentration test is shown in Table 2. Adult crabs were sampled in two parts: cephalothorax and edible parts (parts other than cephalothorax, including crab legs, internal organs, etc.).

[0057]

[0058] Table 2

[0059] Using the independently developed aquatic ecological experimental device, we conducted pollution tests on adult crabs. We collected biological samples and water samples at the same time. 137 Cs, 90 There are two ways to absorb Sr: 1. Through crab meat and shell 137 Cs, 90 2. Absorption of Sr into the water through the internal organs of adult crabs 137 Cs, 90 Sr is then transferred to the meat and shell. The radionuclide activity concentrations in the edible parts and cephalothorax of adult crabs and the supporting water were measured (detailed data omitted).

[0060] The concentration ratio was used to characterize the crabs' 137 Cs, 90 The absorption capacity of Sr was calculated for different parts of adult crabs at different times. 137 Cs, 90 The concentration ratio of Sr is calculated according to the concentration ratio formula in IAEA Technical Report No. 472 (2010) as follows:

[0061]

[0062] Figure 3 and Figure 4 The edible parts of adult crabs at different times are given respectively. 137 Cs, 90The concentration ratio of Sr and the changes of the cephalothorax of adult crabs at different times 137 Cs, 90 Sr concentration ratio variation diagram.

[0063] Figure 3 During the 21-day pollution test, the edible part of adult crabs 137 Cs has a significant concentration effect, and the concentration ratio shows an increasing trend over time. When the pollution test lasts for 1 day, the edible part of adult crabs has a significant effect on 137 The concentration ratio of Cs was 4.1 L / kg. At 21 days, the concentration ratio reached the maximum, and the maximum concentration ratio was 21.1 L / kg. During the 21-day pollution test, the edible part of adult crabs was 90 The concentration ratio of Sr was 1.0 L / kg, and the maximum concentration ratio during the test period was 8.5 L / kg. 90 The concentration effect of Sr is obvious.

[0064] Figure 4 During the 21-day pollution test, the cephalothorax of adult crabs 137 Cs has a significant concentration effect. When the test lasts for 1 day, the head and chest of adult crabs have 137 The concentration ratio of Cs was 3.0L / kg, and the maximum concentration ratio during the test was 25.1L / kg. 90 The concentration ratio of Sr is 0.9L / kg, and the maximum concentration ratio during the test period is 15.4L / kg. 90 Sr has an obvious concentration effect.

[0065] Maximum concentration ratio conclusion:

[0066] As the experiment progressed, we obtained 137 Cs, 90 The maximum concentration ratio of Sr in the edible part of adult crabs 137 Cs, 90 The maximum concentration ratios of Sr were 21.1 L / kg and 8.5 L / kg, respectively. 137 Cs, 90 The maximum concentration ratios of Sr were 25.1 L / kg and 15.4 L / kg, respectively.

[0067] It can be seen from the above embodiments that the present invention forms an experimental device through a glass aquarium, a filter water tank, a water circulation pump, an air pump, and an ultraviolet lamp. The assembly is convenient and quick, and aquatic ecological simulation experiments can be carried out smoothly. The filter material has no adsorption loss on the nuclides, ensuring that the water quality meets the standards, thereby ensuring the normal survival of aquatic organisms. A simulation experiment process method for the ecological transfer of radioactive nuclides in aquatic organisms is proposed. According to the research objectives, representative aquatic organisms are selected as experimental objects, experimental parameters are determined, key nuclides are added to the aquarium water, and ecological transfer simulation experiments of nuclides in different growth periods of aquatic organisms are carried out. It can be used to simulate the water ecosystem of rivers / oceans, study the migration and transformation mechanism of multiple nuclides in aquatic organisms, obtain transfer parameters with site characteristics, improve the accuracy of internal exposure dose estimation in nuclear facility environmental assessment, and provide basic data for nuclear safety goals.

[0068] The present invention is not limited to the embodiments described in the specific implementation manner. Those skilled in the art may derive other implementation manners based on the technical solution of the present invention, which also fall within the technical innovation scope of the present invention.

Claims

1. A radionuclide aquatic biological ecological transfer simulation experimental device, characterized in that: include: A glass aquarium, a filter water tank, a water circulation pump, an air pump and an ultraviolet lamp. The glass aquarium is used to construct an aquatic ecological environment. The filter water tank is provided with filter materials. The water circulation pump is connected to the filter water tank and the glass aquarium respectively, and is used to circulate the water in the glass aquarium through the filter water tank and then return to the glass aquarium. The air pump is used to blow air into the water body, and the ultraviolet lamp is used to sterilize the water body.

2. A radionuclide aquatic biological ecological transfer simulation experimental device as claimed in claim 1, characterized in that: There are multiple filter water tanks, and the multiple filter water tanks are connected in sequence. The water circulation pump is connected to the first filter water tank and the glass aquarium respectively, and the last filter water tank is connected to the glass aquarium.

3. A radionuclide aquatic biological ecological transfer simulation experimental device as claimed in claim 2, characterized in that: The number of the filtering water tanks is three.

4. The radionuclide aquatic biological ecological transfer simulation experimental device according to claim 1, characterized in that: The filter material in the filter tank has five layers.

5. A radionuclide aquatic biological ecological transfer simulation experimental device as claimed in claim 4, characterized in that: The five layers of filter materials are arranged from bottom to top as follows: first layer: ceramic rings, bio-balls; second layer: filter cotton; The third layer: ceramic rings and bio-balls; the fourth layer: filter cotton; the fifth layer: ceramic rings.

6. The radionuclide aquatic biological ecological transfer simulation experimental device according to claim 1, characterized in that: The filter water tank is arranged at one end of the glass aquarium away from the ground.

7. The radionuclide aquatic biological ecological transfer simulation experimental device according to claim 1, characterized in that: The dimensions of the filter tank are: 90 cm long×20 cm wide×20 cm high.

8. The radionuclide aquatic biological ecological transfer simulation experimental device according to claim 1, characterized in that: The dimensions of the glass aquarium are: length 146 cm×width 58 cm×height 71 cm, and a volume of 600 L.

9. The radionuclide aquatic biological ecological transfer simulation experimental device according to claim 1, characterized in that: The water circulation pump: 60w, is placed in the water body, the air pump is placed outside the glass aquarium, and the ultraviolet lamp: 3W, is equipped with a light shield.

10. The experimental method of the radionuclide aquatic biological ecological transfer simulation experimental device according to any one of claims 1 to 9, characterized in that: Includes steps: Determine experimental parameters according to research needs; Establishing aquatic ecological environment; After the introduction of radionuclides, the water circulation was started and aquatic organisms were added for experiments.

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