Estimation method for sampling amount and collection efficiency of tritiated water vapor in ambient air

Abstract

The invention belongs to the technical field of environmental radiation monitoring, and particularly relates to a method for estimating the sampling amount and collection efficiency of tritiated water vapor in environmental air, and the method comprises the steps: setting constant sampling flow and recording interval time by an intelligent recorder after a sampling device arrives at a sampling site, and starting sampling by the sampling device; the intelligent recorder sequentially records corresponding temperature and humidity data according to the interval time; various data recorded on the intelligent recorder are obtained, and the real-time water vapor sampling amount of the sampling device is calculated in real time according to the various data; and the sampling efficiency of the sampling device is calculated according to various data recorded on the intelligent recorder and the real-time sampling amount. According to the method for estimating the sampling amount and the collection efficiency of the tritiated water vapor in the ambient air, the sampling amount and the collection efficiency of the sampling device can be calculated in real time, the accuracy is high, and automatic monitoring and efficiency evaluation in the sampling process are achieved.

Description

Technical Field

[0001] This invention belongs to the field of environmental radiation monitoring technology, specifically relating to a method for estimating the sampling amount and collection efficiency of tritium water vapor in ambient air. Background Technology

[0002] tritium( 3 H or T (also known as superheavy hydrogen) is a radioactive isotope of hydrogen, a low-energy pure beta radionuclide with a maximum energy of 18.6 keV, an average energy of 5.7 keV, and a half-life of 12.33 years. Tritium can enter the human body through respiration and skin penetration, existing in the body as free water tritium and organic tritium, causing internal irradiation of human tissues and organs and resulting in radioactive hazards. Tritium in the air mainly exists in the form of tritized water; therefore, monitoring, managing, and controlling tritium in ambient air water vapor is essential.

[0003] Tritium water vapor in ambient air is mainly collected using condensation and desiccant methods. Regardless of the method used, real-time monitoring of the sampling volume and determination of sampling completion are crucial for sampling personnel. This avoids frequent trips to sampling locations to confirm completion, reducing manpower and material costs. Simultaneously, sampling efficiency is a factor affecting the accuracy of tritium water vapor activity concentration calculations; inaccurate sampling efficiency leads to inaccurate activity concentration results. However, current sampling instruments cannot provide accurate real-time data on sampling volume and efficiency during dynamic sampling processes, posing challenges to the sampling process and subsequent calculations. Summary of the Invention

[0004] To address the limitations of existing sampling instruments in real-time monitoring of sampling volume, which necessitates frequent manual confirmation of sampling progress and increases labor costs, and the inability to provide accurate real-time data on sampling volume and collection efficiency for dynamic sampling processes, this invention offers a method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air. This method can calculate the sampling volume and collection efficiency of the sampling device in real time with high accuracy, enabling automated monitoring and efficiency evaluation of the sampling process.

[0005] The technical solution of the present invention is as follows:

[0006] A method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air includes a sampling device, which comprises an air filter, a flow meter, an inlet thermo-hygrometer, a first drying bottle, a second drying bottle, an outlet thermo-hygrometer, a third drying bottle, a vacuum gauge, and a vacuum pump connected in sequence; the inlet thermo-hygrometer and the outlet thermo-hygrometer are both connected to an intelligent recorder.

[0007] The estimation method includes the following steps:

[0008] Step 1: After the sampling device arrives at the sampling location, set a constant sampling flow rate and a smart recorder recording interval. The sampling device starts sampling, and the smart recorder records the corresponding temperature and humidity data sequentially according to the interval.

[0009] Step 2: Acquire the various data recorded on the smart recorder, and calculate the real-time water vapor sampling volume of the sampling device based on the data.

[0010] Step 3: Calculate the sampling efficiency of the sampling device based on the data recorded on the smart recorder and the real-time sampling volume.

[0011] Preferably, the data includes sampling flow rate, inlet humidity, inlet temperature, outlet temperature, and outlet humidity.

[0012] Preferably, the formula for calculating the real-time water vapor sampling amount is as follows:

[0013]

[0014] Among them, V t The unit is the volume of air collected at each recording interval, and the unit is m. 3 V represents the sampling flow rate set on the sampling instrument, in L / min; 60 is the conversion factor between minutes and seconds, in s / min; 1000 is the conversion factor between liters and cubic meters, in L / m³. 3 t represents the interval at which the smart recorder records temperature and humidity data, measured in seconds (s).

[0015]

[0016] Where: m i is the mass of water vapor obtained during the i-th recording interval; 18.015 is the molar mass of water; P i V represents the saturated vapor pressure corresponding to the temperature data of the inlet or outlet collected by the i-th recorder; 100 is the conversion coefficient between Pa and hPa; V t The air volume collected at unit recording intervals; RH i Let represent the inlet or outlet humidity data collected by the i-th recorder; R is the ideal gas constant, 8.314 m. 3 ·Pa / (K·mol); T i The temperature data of the air inlet or outlet collected by the i-th recorder;

[0017]

[0018] In the formula, M1 is the cumulative mass of water vapor entering the air inlet of the sampling device when the recorder records up to the nth data point;

[0019]

[0020] In the formula: M2 is the cumulative mass of water vapor discharged from the sampling instrument outlet when the recorder records up to the nth data point;

[0021] M = M1 - M2

[0022] In the formula: M is the mass of water vapor collected by the sampling instrument when the recorder records up to the nth data point.

[0023] Preferably, the saturated water vapor pressure P i The calculation formula is as follows:

[0024]

[0025] P i Let be the saturated vapor pressure (hPa) corresponding to the temperature data (intake or exhaust) collected by the i-th recorder;

[0026] T is the triple point temperature of water, 273.16 K;

[0027] T1 is the thermodynamic temperature collected by the i-th recorder, T1 = T i +273.15K.

[0028] Preferably, M1 is the cumulative mass of water vapor entering the sampling instrument's air inlet when the recorder has recorded up to the nth data point, as shown in the following formula:

[0029]

[0030] The cumulative mass of water vapor M2 discharged from the sampling instrument's outlet when the recorder has recorded the nth data point is given by the following formula:

[0031]

[0032] Preferably, a needle valve is provided between the vacuum pump and the vacuum gauge.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) Real-time performance: Dynamically estimate sampling volume and efficiency to reduce manual intervention;

[0035] (2) Accuracy: The influence of temperature and humidity is corrected by thermodynamic model, the maximum sampling deviation is ≤3.4g, and the efficiency deviation is ≤3.2%;

[0036] (3) Universality: Applicable to various sampling devices such as condensation method and desiccant method, providing theoretical support for instrument design.

[0037] (4) This invention can be widely applied to tritium monitoring in scenarios such as the vicinity of nuclear facilities and laboratories, improving sampling efficiency and data accuracy, and providing technical support for radiation protection and environmental management. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the data acquisition device of the present invention;

[0039] In the diagram: 1-Air filter; 2-Flow meter; 3-Inlet temperature and humidity meter; 4-First drying bottle; 5-Second drying bottle; 6-Outlet temperature and humidity meter; 7-Third drying bottle; 8-Vacuum gauge; 9-Vacuum pump; 10-Smart recorder; 11-Needle valve. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0041] See Figure 1 A method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air includes a sampling device. The sampling device includes an air filter 1, a flow meter 2, an inlet thermo-hygrometer 3, a first drying bottle 4, a second drying bottle 5, an outlet thermo-hygrometer 6, a third drying bottle 7, a vacuum gauge 8, and a vacuum pump 9, which are connected in sequence. The inlet thermo-hygrometer 3 and the outlet thermo-hygrometer 6 are both connected to an intelligent recorder 10.

[0042] The estimation method includes the following steps:

[0043] Step 1: After the sampling device arrives at the sampling location, set a constant sampling flow rate and a smart recorder recording interval. The sampling device starts sampling, and the smart recorder 10 records the corresponding temperature and humidity data sequentially according to the interval.

[0044] Step 2: Acquire the various data recorded on the smart recorder 10, and calculate the real-time water vapor sampling volume of the sampling device based on the various data;

[0045] Step 3: Calculate the sampling efficiency of the sampling device based on the data recorded on the smart recorder 10 and the real-time sampling volume.

[0046] In this invention, the data includes sampling flow rate, inlet humidity, inlet temperature, outlet temperature, and outlet humidity;

[0047] In a preferred embodiment of the present invention, the model of the smart recorder may be the Shenzhen Topray TP740 paperless recorder.

[0048] In one embodiment of the present invention, the formula for calculating the real-time water vapor sampling amount is as follows:

[0049]

[0050] Among them, V t The unit is the volume of air collected at each recording interval, and the unit is m. 3 V represents the sampling flow rate set on the sampling instrument, in L / min; 60 is the conversion factor between minutes and seconds, in s / min; 1000 is the conversion factor between liters and cubic meters, in L / m³. 3 t represents the interval at which the smart recorder records temperature and humidity data, measured in seconds (s).

[0051]

[0052] Where: m i is the mass of water vapor obtained during the i-th recording interval; 18.015 is the molar mass of water; P i V represents the saturated vapor pressure corresponding to the temperature data of the inlet or outlet collected by the i-th recorder; 100 is the conversion coefficient between Pa and hPa; V t The air volume collected at unit recording intervals; RH i Let represent the inlet or outlet humidity data collected by the i-th recorder; R is the ideal gas constant, 8.314 m. 3 ·Pa / (K·mol); T i The temperature data of the air inlet or outlet collected by the i-th recorder;

[0053]

[0054] In the formula, M1 is the cumulative mass of water vapor entering the air inlet of the sampling device when the recorder records up to the nth data point;

[0055]

[0056] In the formula: M2 is the cumulative mass of water vapor discharged from the sampling instrument outlet when the recorder records up to the nth data point;

[0057] M = M1 - M2

[0058] In the formula: M is the mass of water vapor collected by the sampling instrument when the recorder records up to the nth data point.

[0059] In one embodiment of the present invention, the saturated water vapor pressure P i The calculation formula is as follows:

[0060]

[0061] P i Let be the saturated vapor pressure (hPa) corresponding to the temperature data (intake or exhaust) collected by the i-th recorder;

[0062] T is the triple point temperature of water, 273.16 K;

[0063] T1 is the thermodynamic temperature collected by the i-th recorder, T1 = T i +273.15K.

[0064] In one embodiment of the present invention, M1 is the cumulative mass of water vapor entering the air inlet of the sampling instrument when the recorder records up to the nth data point, and the formula is as follows:

[0065]

[0066] The cumulative mass of water vapor M2 discharged from the sampling instrument's outlet when the recorder has recorded the nth data point is given by the following formula:

[0067]

[0068] In one embodiment of the present invention, a needle valve is provided between the vacuum pump and the vacuum gauge.

[0069] Acquire the data recorded by the recorder and calculate the following parameters according to the estimation method described above: the mass of water vapor entering through the air inlet, the mass of water vapor exiting through the air outlet, the sampling volume, and the sampling efficiency. Compare the estimated sampling volume and sampling efficiency with the actual sampling volume and sampling efficiency. The comparison deviation data are shown in Tables 1 and 2.

[0070] Table 1. Experimental data for verifying the deviation of the sampling estimation method.

[0071]

[0072]

[0073] Table 2. Experimental data for verifying the deviation of the sampling efficiency estimation method.

[0074]

[0075]

[0076] As shown in Tables 1 and 2, this estimation method accurately reflects the sampling status of the sampling device. The maximum deviation between the estimated and actual sampling volume is 3.4 g, and the maximum deviation between the estimated and actual sampling efficiency is 3.2%. This estimation method allows for real-time acquisition of the sampling volume and efficiency of the sampling device, effectively addressing existing problems in current sampling instruments and providing a reference for the design of future sampling instruments for tritium water vapor in ambient air.

[0077] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air, characterized in that, The device includes a sampling apparatus, which comprises an air filter, a flow meter, an inlet temperature and humidity meter, a first drying bottle, a second drying bottle, an outlet temperature and humidity meter, a third drying bottle, a vacuum gauge, and a vacuum pump, all connected in sequence. The inlet and outlet temperature and humidity meters are both connected to an intelligent recorder. The estimation method includes the following steps: Step 1: After the sampling device arrives at the sampling location, set a constant sampling flow rate and a smart recorder recording interval. The sampling device starts sampling, and the smart recorder records the corresponding temperature and humidity data sequentially according to the interval. Step 2: Acquire the various data recorded on the smart recorder, and calculate the real-time water vapor sampling volume of the sampling device based on the data. Step 3: Calculate the sampling efficiency of the sampling device based on the data recorded on the smart recorder and the real-time sampling volume.

2. The method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air according to claim 1, characterized in that, The data includes sampling flow rate, inlet humidity, inlet temperature, outlet temperature, and outlet humidity.

3. The method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air according to claim 2, characterized in that, The formula for calculating the real-time water vapor sampling volume is as follows: Among them, V t The unit is the volume of air collected at each recording interval, and the unit is m. 3 V represents the sampling flow rate set on the sampling instrument, in L / min; 60 is the conversion factor between minutes and seconds, in s / min; 1000 is the conversion factor between liters and cubic meters, in L / m³. 3 t represents the interval at which the smart recorder records temperature and humidity data, measured in seconds (s). Where: m i is the mass of water vapor obtained during the i-th recording interval; 18.015 is the molar mass of water; P i V represents the saturated vapor pressure corresponding to the temperature data of the inlet or outlet collected by the i-th recorder; 100 is the conversion coefficient between Pa and hPa; V t The air volume collected at unit recording intervals; RH i Let represent the inlet or outlet humidity data collected by the i-th recorder; R is the ideal gas constant, 8.314 m. 3 ·Pa / (K·mol); T i The temperature data of the air inlet or outlet collected by the i-th recorder; In the formula, M1 is the cumulative mass of water vapor entering the air inlet of the sampling device when the recorder records up to the nth data point; In the formula: M2 is the cumulative mass of water vapor discharged from the sampling instrument outlet when the recorder records up to the nth data point; M = M1 - M2 In the formula: M is the mass of water vapor collected by the sampling instrument when the recorder records up to the nth data point.

4. The method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air according to claim 3, characterized in that, Saturated vapor pressure P i The calculation formula is as follows: P i Let be the saturated vapor pressure (hPa) corresponding to the temperature data (intake or exhaust) collected by the i-th recorder; T is the triple point temperature of water, 273.16 K; T1 is the thermodynamic temperature collected by the i-th recorder, T1 = T i +273.15K.

5. The method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air according to claim 4, characterized in that, M1 represents the cumulative mass of water vapor entering the sampling instrument's air inlet when the recorder has recorded up to the nth data point, as shown in the following formula: The cumulative mass of water vapor M2 discharged from the sampling instrument's outlet when the recorder has recorded the nth data point is given by the following formula:

6. The method for estimating the sampling volume and collection efficiency of tritium water vapor in ambient air according to claim 1, characterized in that, A needle valve is installed between the vacuum pump and the vacuum gauge.

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