Device and method for measuring water surface radon exhalation rate and calculating radon concentration in water

Abstract

The invention discloses a device and a method for calculating radon concentration in water by measuring a radon exhalation rate on a water surface. The device comprises a static floating chamber, an air inlet pipe, an air outlet pipe, a foam plate, a drying bottle and an RAD7 radon measuring instrument, the cystosepiment is arranged around the static floating chamber and is fixedly connected with the static floating chamber, and the air outlet pipe, the drying bottle and the RAD7 emanometer are sequentially connected with the static floating chamber. Normal connection and measurement use of the device are controlled, balanced radon concentration data is achieved through a measurement process recording system, a corresponding calculation formula of the water surface radon exhalation rate and the water radon concentration is deduced, the water surface radon exhalation rate J is fitted through a Po-218 radon concentration curve measured by an RAD7 radon measurement instrument, and the water surface radon exhalation rate J is calculated. And calculating the radon concentration in the water according to the obtained radon exhalation rate on the water surface. The device is simple in structure and convenient to operate, the measured result is convenient and easy to read, and the calculated radon concentration in water is high in accuracy; the radon concentration in the water sample is continuously monitored and analyzed for a long time, and a basis is provided for subsequent treatment.

Description

Technical Field

[0001] The present invention relates to a nuclear radiation detection technology, in particular to a device and method for measuring the radon exhalation rate on a water surface and calculating the radon concentration in water. Background Art

[0002] Radon is a naturally occurring radioactive gas commonly found in soil and water, and enters the air through precipitation from water surfaces. Radon concentration plays a crucial role in environmental monitoring and water quality assessment, particularly in groundwater and drinking water safety testing. Therefore, accurately measuring radon concentrations in water and the rate of radon precipitation from water surfaces is crucial for aquatic environmental protection and public health and safety.

[0003] Currently, radon concentration measurement methods primarily rely on direct sampling and detection of radon gas, using radon detectors such as the RAD7. However, existing measurement technologies have several drawbacks, primarily due to their complex measurement process, significant impact on data accuracy due to environmental factors, cumbersome operation, and the time required to obtain stable measurement results. These issues are particularly prominent in long-term, continuous monitoring projects, limiting their application in water quality monitoring and water resource protection.

[0004] Traditional methods rely on collecting water samples and analyzing their radon content, or inferring radon concentrations through indirect experimental methods. However, these methods typically require long experimental cycles and are complex to operate, failing to meet the demands of rapid response and real-time monitoring. Therefore, it is imperative to quickly and accurately measure radon-220 concentrations in water. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a device and method for measuring the radon exhalation rate on a water surface and calculating the radon concentration in water.

[0006] The technical solution of the present invention is: a device for measuring the radon exhalation rate of a water surface and calculating the radon concentration in water, comprising a static floating chamber, an air inlet pipe, an air outlet pipe, a foam board, a drying bottle, and a RAD7 radon detector; the foam board is arranged around the static floating chamber and fixedly connected to the static floating chamber; a substance for drying gas is placed in the drying bottle; the air inlet pipe and the air outlet pipe are respectively installed on the static floating chamber; the air outlet pipe is connected to the air inlet end of the drying bottle through a hose; the air outlet end of the drying bottle is connected to the air inlet end of the RAD7 radon detector through a hose; and the air outlet end of the RAD7 radon detector is connected to the air inlet pipe of the static floating chamber through a hose.

[0007] A further technical solution of the present invention is: calcium chloride powder is placed in the drying bottle.

[0008] Another technical solution of the present invention is: a method for applying a device for measuring the radon exhalation rate on the water surface to calculate the radon concentration in water, including a measurement process and a calculation process, and the specific steps are as follows: I. Measurement process Place the static floating chamber and the surrounding foam board on the water surface of the water sample to be measured, start the pump of the RAD radon detector, and the radon-containing air in the static floating chamber enters the drying bottle through the air outlet pipe under the action of the pump for drying and then enters the RAD7 radon detector. When the radon concentration data measured by the RAD7 radon detector basically does not change, that is, the radon concentration measured in the RAD7 radon detector reaches equilibrium, record the radon concentration curve of the gas measured by the RAD7 radon detector from startup to the equilibrium state.

[0009] II. Calculation process The radon concentration in water mainly comes from the decay of radium dissolved in water. The radon in water is released into the air through the water-air interface, which is the radon exhalation on the water surface. Since the water volume is approximately infinite during the measurement process, assuming that the radon concentration in water remains unchanged when measuring the radon exhalation rate on the water surface, the radon concentration in the static floating chamber is expressed by formula (1): (1) Wherein, c C(t) is the radon concentration in the static floating chamber, with the unit of Bq / m 3 ; S S is the area of the water surface in the static floating chamber in contact with the air, with the unit of m 2 ; V V is the gas path volume, including the volume of the static floating chamber, the volume of the gas in the drying bottle and the volume of the connecting hose, with the unit of m 3 ; c(H 2 O) Cw is the radon concentration in water, with the unit of Bq / m 3 ; A 1 Kw is the rate of radon concentration in the air entering the water surface, with the unit of m / s; A 2 Ka is the rate of radon concentration on the water surface entering the air, with the unit of m / s; λ λ is the decay constant of radon; λ l β is the leakage coefficient of radon.

[0010] Let the effective decay constant of radon be: (2) And the radon exhalation rate J on the water surface is the product of the rate of radon in water entering the air and the radon concentration in water, and is expressed as: (3) Therefore, according to formulas (2) and (3), formula (1) can be simplified to the following expression: (4) Solving formula (4) gives the following expression for the static floating indoor radon concentration: (5) Where, c 0 represents the initial radon concentration, i.e., the radon concentration in the environment. Since the range of the initial water surface is very large and the radon concentration in the environment is very low and can be basically ignored, formula (5) is simplified to: (6) Since the RAD7 radon detector cannot directly measure the radon concentration, but measures the concentration of the radon daughter Po-218 in the internal measurement cavity of the RAD7 radon detector 6, the calculation expression for the concentration of the radon daughter Po-218 in the internal measurement cavity of the RAD7 radon detector 6 is: (7) Where, c po (t) represents the concentration of Po-218 in the measurement cavity of the RAD7 radon detector, with the unit of Bq / m 3 ; λ po represents the decay constant of Po-218. Substituting the measured radon concentration curve into formula (7) for non-linear fitting gives the radon exhalation rate of the water surface J。

[0011] Under the condition of constant temperature, A 2 is a constant value, and thus the calculation expression for the radon concentration in water is: (8) Substitute A 2 and the radon exhalation rate J of the water surface obtained by fitting formula (7) into formula (8) to calculate the radon concentration in water.

[0012] The present invention has the following advantages compared with the prior art: 1. The device for measuring the radon exhalation rate of the water surface and calculating the radon concentration in water provided by the present invention has a simple structure, is easy to operate, and has a short measurement time.

[0013] 2. The calculation process of radon concentration in water by the measurement method provided by the present invention is simple, and the calculation result is accurate. It can provide a basis for the state to formulate healthy drinking water standards and for water pollution treatment, national disease prevention and treatment, agricultural and livestock water use, etc. by continuously monitoring and analyzing the radium concentration in groundwater samples in a certain area, ensuring the safety of the groundwater environment and residents' drinking water.

[0014] The detailed structure of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of a device for measuring the radon exhalation rate on the water surface and calculating the radon concentration in water; Figure 2 It is a top view of the static floating chamber in the working state. Specific Embodiments

[0016] Example 1. As Figure 1-2 shown, a device for measuring the radon exhalation rate on the water surface and calculating the radon concentration in water includes a static floating chamber 1, an intake pipe 2, an exhaust pipe 3, a foam board 4, a drying bottle 5, and a RAD7 radon detector 6. The foam board 4 is arranged around the static floating chamber 1 and fixedly connected to the static floating chamber 1, enabling the static floating chamber 1 to float on the water surface to be measured. Substances for drying gases, such as calcium chloride powder, etc., are placed in the drying bottle 5. The intake pipe 2 and the exhaust pipe 3 are respectively installed on the static floating chamber 1. The exhaust pipe 3 is connected to the intake end of the drying bottle 5 through a hose. The exhaust end of the drying bottle 5 is connected to the intake end of the RAD7 radon detector 6 through a hose. The exhaust end of the RAD7 radon detector 6 is connected to the intake pipe 2 of the static floating chamber 1 through a hose.

[0017] Example 2. A method applied to the device for measuring the radon exhalation rate on the water surface and calculating the radon concentration in water in Example 1 includes a measurement process and a calculation process, and the specific steps are as follows: I. Measurement Process Place the static floating chamber 1 and the surrounding foam board 4 on the water surface of the water sample 7 to be measured. Start the pump of the RAD7 radon detector ⑥. The radon-containing air in the static floating chamber 1 enters the drying bottle 5 through the exhaust pipe 3 under the action of the pump for drying, and then enters the RAD7 radon detector 6. When the radon concentration data measured by the RAD7 radon detector 6 basically does not change, that is, when the radon concentration measured in the RAD7 radon detector 6 reaches equilibrium, record the radon concentration curve of the gas measured by the RAD7 radon detector from startup to the equilibrium state.

[0018] II. Calculation Process The radon concentration in water mainly comes from the decay of radium dissolved in water. The radon in water is released into the air through the water-air interface, which is the radon exhalation from the water surface. Since the water volume is approximately infinite during the measurement process, assuming that the radon concentration in water remains unchanged when measuring the radon exhalation rate from the water surface, the radon concentration in the static floating chamber is expressed by Equation (1): (1) Wherein, c C(t) is the radon concentration in the static floating chamber 1, with the unit of Bq / m 3 ; S S is the area of the water surface in contact with the air in the static floating chamber 1, with the unit of m 2 ; V V is the gas path volume, including the volume of the static floating chamber 1, the volume of the gas in the drying bottle, and the volume of the connecting hose, with the unit of m 3 ; c(H 2 O) Cw is the radon concentration in water, with the unit of Bq / m 3 ; A 1 Ka is the rate of radon concentration in the air entering the water surface, with the unit of m / s; A 2 Ke is the rate of radon concentration on the water surface entering the air, with the unit of m / s; λ λ is the decay constant of radon; λ l β is the leakage coefficient of radon.

[0019] Let the effective decay constant of radon be:[[]] (2) And the radon exhalation rate J from the water surface is the product of the rate of radon in water entering the air and the radon concentration in water, expressed as:[[]] (3) Therefore, according to Equation (2) and Equation (3), Equation (1) can be simplified to the following expression:[[]] (4) Solving Equation (4) gives the following expression for the radon concentration in the static floating chamber 1:[[]] (5) Wherein, c C0 represents the initial radon concentration, i.e., the radon concentration in the environment. Since the initial water surface area is very large and the radon concentration in the environment is very low and can be basically ignored, Equation (5) is simplified to:[[]] (6) Since the RAD7 radon detector 6 cannot directly measure the radon concentration, but measures the concentration of radon daughter Po-218 in the internal measurement chamber of the RAD7 radon detector 6. The calculation expression for the concentration of radon daughter Po-218 in the internal measurement chamber of the RAD7 radon detector 6 is: (7) Where, c po (t) represents the concentration of Po-218 in the measurement chamber of the RAD7 radon detector 6, with the unit of Bq / m 3 ; λ po represents the decay constant of Po-218. Substitute the measured radon concentration curve into formula (7) for non-linear fitting to obtain the radon exhalation rate of the water surface J .

[0020] Under the condition of constant temperature, A 2 is a fixed value, obtained by referring to existing literature or experiments. Thus, the calculation expression for the radon concentration in water is: (8) Substitute A 2 and the radon exhalation rate J of the water surface obtained by fitting formula (7) into formula (8) to calculate the radon concentration in water.

Claims

1. An apparatus for measuring the radon exhalation rate on the water surface to calculate the radon concentration in water, characterized in that: It includes a static floating chamber, an intake pipe, an outlet pipe, a foam board, a drying bottle and a RAD7 radon detector; the foam board is arranged around the static floating chamber and fixedly connected to the static floating chamber. A substance for drying gas is placed in the drying bottle. The intake pipe and the outlet pipe are respectively installed on the static floating chamber. The outlet pipe is connected to the intake end of the drying bottle through a hose. The outlet end of the drying bottle is connected to the intake end of the RAD7 radon detector through a hose. The outlet end of the RAD7 radon detector is connected to the intake pipe of the static floating chamber through a hose.

2. The device for measuring the radon exhalation rate on the water surface and calculating the radon concentration in water according to claim 1, characterized in that: Calcium chloride powder is placed in the drying bottle.

3. A method applied to the device for measuring the radon exhalation rate of the water surface and calculating the radon concentration in water according to claim 1 or 2, characterized in that: It includes a measurement process and a calculation process, and the specific steps are as follows. I. Measurement process Place the static floating chamber and the surrounding foam board on the water surface of the water sample to be measured. Start the pump of the RAD radon detector. The radon-containing air in the static floating chamber enters the drying bottle through the outlet pipe under the action of the pump for drying and then enters the RAD7 radon detector. When the radon concentration data measured by the RAD7 radon detector basically does not change, that is, the radon concentration measured in the RAD7 radon detector reaches equilibrium, record the radon concentration curve of the gas measured by the RAD7 radon detector from startup to the equilibrium state. II. Calculation process The radon concentration in water mainly comes from the decay of radium dissolved in water. The radon in water is released into the air through the water-air interface, which is the precipitation of radon on the water surface. Since the water volume is approximately infinite during the measurement process, assuming that the radon concentration in water remains unchanged when measuring the radon precipitation rate on the water surface, the radon concentration in the static floating chamber is expressed by formula (1): （1） Among them, c (t) is the static floating indoor radon concentration, with the unit of Bq / m 3 ; S is the area of the water surface in the static floating indoor contacting with the air, with the unit of m 2 ; V is the volume of the gas path, including the volume of the static floating chamber, the volume of the gas in the drying bottle and the volume of the connecting hose, with the unit of m 3 ; c(H 2 O) is the radon concentration in water, with the unit of Bq / m 3 ; A 1 is the rate of the radon concentration in the air entering the water surface, with the unit of m / s; A 2 is the rate of the radon concentration in the water surface entering the air, with the unit of m / s; λ is the decay constant of radon; λ l is the leakage coefficient of radon; Let the effective decay constant of radon be: （2） The radon exhalation rate of the water surface J It is the product of the rate at which radon in water enters the air and the radon concentration in the water, expressed as: （3） Therefore, according to formula (2) and formula (3), formula (1) can be simplified to the following expression: （4） Solve formula (4) to obtain the following expression for the radon concentration in the static floating chamber: （5） Among them, c 0 represents the initial radon concentration, that is, the radon concentration in the environment. Since the range of the initial water surface is very large and the radon concentration in the environment is very low and can be basically ignored, formula (5) is simplified to: （6） Since the RAD7 radon detector cannot directly measure the radon concentration, but measures the concentration of radon daughter Po-218 in the internal measurement chamber of the RAD7 radon detector 6. The calculation expression for the concentration of radon daughter Po-218 in the internal measurement chamber of the RAD7 radon detector 6 is: （7） Among them, c po (t) represents the concentration of Po-218 in the measurement chamber of the RAD7 radon detector, with the unit of Bq / m 3 ; λ po represents the decay constant of Po-218. The measured radon concentration curve is substituted into formula (7) for non-linear fitting to obtain the radon exhalation rate of the water surface J ; At a constant temperature, A 2 is a constant value, and thus the calculation expression for the radon concentration in water is: （8） Will A 2 The radon exhalation rate of the water surface obtained by fitting formula (7) J Substitute into formula (8) to calculate the radon concentration in water.

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