Method for measuring sampling efficiency of bubbling tritium sampler

Abstract

The invention relates to a method for measuring the sampling efficiency of a bubbling tritium sampler, which is characterized in that gas generated by a water vapor generator is introduced into the tritium sampler, the sampling flow in a gas circuit is controlled by a flow meter, and after sampling is finished, the sampling efficiency is the ratio of the increased mass of the tritium sampler to the reduced mass of the water vapor generator. According to the method, the non-radioactive method that water vapor generated by the water vapor generator serves as a sampling gas source to replace a tritiated water vapor gas source is achieved, meanwhile, a weighing method is adopted for measuring and calculating the sampling efficiency of the bubbling method tritium sampler and the sampling device, the problem that tritiated water vapor activity concentration tracing is difficult is effectively solved, and the sampling efficiency of the sampling device is improved. Pollution to a tritium sampler and a sampler and risks of tritiated water vapor leakage possibly caused in the efficiency measurement process by using a tritiated water vapor source are avoided. The invention provides a convenient, quick, pollution-free and safe measuring method for measuring the sampling efficiency of the bubbling tritium sampler and the sampler. The radioactive source does not need to be operated.

Description

Technical Field

[0001] The invention relates to the technical field of sample sampling efficiency measurement, and in particular to a method for measuring the sampling efficiency of a bubbling method tritium sampler. Background Art

[0002] In environmental monitoring and gas monitoring processes at industrial sites, chimney exhaust streams, process pipelines, glove box atmospheres, etc., the use of tritium samplers and samplers is a key tool to ensure safe and compliant gas emissions. These devices are mainly used to detect and quantify the concentration of tritium (a radioactive isotope) in the air or exhaust to assess potential radiation exposure risks. As a commonly used sampling technique, the bubbling method is widely used due to its simplicity and effectiveness.

[0003] The bubbling method is a physical and chemical process that introduces air or other gases into a container containing an absorption liquid so that the target substance (such as tritiated water vapor HTO) in the gas is dissolved into the liquid, thereby achieving separation and capture. Specifically, when the gas passes through a bubbling bottle filled with a specific solvent (usually water or an aqueous solution), the solvent can effectively absorb the tritiated water vapor in the gas. Although the device used in the bubbling method has a simple structure and low cost, it is very important whether it can capture the target gas to the maximum extent. If the sampling efficiency is low, part of the target gas may not be captured, resulting in a low measurement result that cannot truly reflect the actual concentration. How to ensure the efficient sampling efficiency of the bubbling method is the key to ensuring the reliability and repeatability of the measurement data.

[0004] There are usually two main methods for determining the sampling efficiency of tritium samplers and samplers: theoretical calculation method and experimental measurement method. The theoretical calculation method is based on the basic principle of the bubbling method and uses mathematical models to predict and calculate the sampling efficiency. This method relies on a series of assumptions and physical and chemical laws, such as gas solubility, diffusion coefficient, flow rate, temperature and pressure. The specific calculation formulas involved are Henry's law, Ficker's first law, mass transfer coefficient, etc. In theory, these formulas can be used in combination with specific equipment geometry and operating conditions to calculate the expected sampling efficiency. However, due to the complexity and variability of actual operating conditions, theoretical calculations are often difficult to accurately reflect the actual situation, so they are often used as preliminary estimates or auxiliary means. The experimental measurement method is more direct. It involves using standard tritium water (HTO) with known activity concentration to generate tritiated water vapor through bubbling method, and then allowing this vapor to be captured by the bubbler (absorption bottle) of the sampler or sampler. After that, the amount of tritium captured in the absorption bottle is measured by a liquid scintillation counter (LSC) to determine the sampling efficiency. Although this method of experimental measurement can provide relatively accurate sampling efficiency data, it also has some problems:

[0005] (1) Traceability issue: The activity of standard tritium water with known activity concentration cannot be fully traced back to the international standard, which will affect the accuracy of the measurement results.

[0006] (2) Pollution risk: When handling radioactive materials, any leakage may cause contamination of the environment and personnel.

[0007] (3) Safety risks: If tritiated water vapor leaks during operation, it will not only cause environmental pollution but also pose a threat to the health of operators.

[0008] Therefore, there is an urgent need for a convenient, fast, pollution-free, radioactive source-free and safe method for determining the sampling efficiency of a bubbling tritium sampler. Summary of the invention

[0009] The invention discloses a method for determining the sampling efficiency of a tritium sampler using a bubbling method, so as to solve the problems of low accuracy, pollution and safety risks in the above tritium sampler and the method for determining the sampling efficiency of the sampler.

[0010] The present invention adopts the following technical solutions:

[0011] The first aspect of the present invention provides a method for determining the sampling efficiency of a bubbling tritium sampler, comprising the following steps: passing the gas generated by a water vapor generator into the tritium sampler, the tritium sampler comprising a plurality of absorption bottles, the absorption bottles being filled with absorbents, the plurality of absorption bottles being connected in series in sequence, the first absorption bottle being connected to the water vapor generator via a gas pipeline, the gas pipeline being provided with a vacuum pump and a flow regulating valve, the sampling flow in the gas circuit being controlled by a flow meter, and after the sampling is completed, the sampling efficiency is the ratio of the mass increased by the tritium sampler to the mass reduced by the water vapor generator.

[0012] Preferably, the tritium sampler includes a first-stage absorption bottle and a second-stage absorption bottle connected in series in sequence, one end of the first-stage absorption bottle is connected to the water vapor generator through a gas pipe, the other end of the first-stage absorption bottle is connected to one end of the second-stage absorption bottle, and the other end of the second-stage absorption bottle is connected to an exhaust pipe, and a flow meter is provided on the exhaust pipe.

[0013] Preferably, the absorbent is ethanol.

[0014] Preferably, the sampling flow rate includes the instantaneous flow rate and the cumulative sampling flow rate displayed by the flow meter, wherein the instantaneous flow rate is 55-65 L / h and the cumulative sampling flow rate is 0.5-2 m / h. 3 .

[0015] Preferably, the instantaneous flow rate is 60L / h and the cumulative sampling flow rate is 1.5m 3 .

[0016] Preferably, the sampling efficiency=(the weight gain of the first-stage absorption bottle+the weight gain of the second-stage absorption bottle) / the weight loss of the water vapor generator×100%.

[0017] Preferably, the sampling efficiency is measured to be above 99% by the measuring method.

[0018] The second aspect of the present invention provides a bubbling method tritium sampler sampling device, including a water vapor generator and a tritium sampler. The tritium sampler includes a plurality of absorption bottles, which are connected in series in sequence. The first absorption bottle is connected to the water vapor generator through a gas pipeline, and the last absorption bottle is connected to the exhaust pipeline.

[0019] Preferably, a vacuum pump and a flow regulating valve are sequentially arranged on the gas pipeline along the gas flow direction, and a flow meter is arranged on the exhaust pipeline.

[0020] Preferably, the gas pipeline at one end for introducing gas into the absorption bottle extends below the ethylene glycol liquid level, and the gas pipeline at one end for discharging gas is located above the ethylene glycol liquid level.

[0021] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0022] (1) The traditional bubbling method for sampling efficiency determination usually relies on standard tritium water (HTO) with known activity concentration, and the tritiated water vapor is generated by the bubbling method for testing. However, this method has obvious safety hazards, including the risk of leakage of tritiated water vapor and potential pollution to the environment and personnel. The present invention completely avoids the use of radioactive materials by using a water vapor generator to generate water vapor as the sampling gas source. This not only eliminates the safety risks brought by the operation of radioactive materials, but also simplifies the experimental operation process and reduces the need for special protective equipment.

[0023] (2) The tritiated water vapor produced by the traditional method using standard tritium water with known activity concentration is difficult to trace back to the international standard, which affects the accuracy of the measurement results. The present invention directly measures the mass reduced by the water vapor generator and the mass increased by the tritium sampler by weighing, thereby calculating the sampling efficiency. This measurement method based on the law of conservation of mass is more intuitive and reliable, and can provide more accurate sampling efficiency data.

[0024] (3) The present invention simplifies the entire sampling efficiency measurement operation process, uses a water vapor generator and a flow meter to control the sampling flow in the gas path, and makes the experimental device simpler and easier to use. At the same time, the design of multiple absorption bottles connected in series can effectively improve the capture efficiency and reduce sample loss. In addition, the setting of the vacuum pump and the flow regulating valve makes the flow control more accurate and the operation more convenient.

[0025] (4) When using tritiated water vapor to measure sampling efficiency in the traditional method, there is a great risk of environmental pollution. Even if strict safety measures are taken, the possibility of leakage cannot be completely eliminated. The present invention completely eliminates this risk by using water vapor as the sampling gas source. Water vapor itself is non-toxic and harmless, and even if leakage occurs, it will not cause any pollution to the environment.

[0026] (5) The present invention uses a water vapor generator and a weighing method to determine the sampling efficiency of a bubbling tritium sampler and a sampler, thereby avoiding the use of radioactive substances, improving the accuracy of measurement results, simplifying the operating procedures, and reducing the risk of environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0028] Figure 1 This is a flow chart for determining the sampling efficiency of Example 1.

[0029] Description of reference numerals:

[0030] 1. Water vapor generator; 2. Vacuum pump; 3. Flow regulating valve; 4. First-stage absorption bottle; 5. Second-stage absorption bottle; 6. Ethylene glycol; 7. Flow meter. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically limited.

[0033] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The present embodiment provides a method for determining the sampling efficiency of a tritium sampler using a bubbling method, comprising the following steps: passing the gas generated by a water vapor generator into the tritium sampler, controlling the sampling flow rate in the gas path by a flow meter, and after the sampling is completed, the sampling efficiency is the ratio of the mass increased by the tritium sampler to the mass reduced by the water vapor generator.

[0035] At present, the most accurate method for determining the sampling efficiency of the bubbling tritium sampler is experimental measurement. However, this method requires standard tritium water with known activity concentration as raw material, generates tritiated water vapor by bubbling method, and then uses a sampler or sampler to capture the above tritiated water vapor. Finally, a liquid scintillation counter is used to measure the amount of tritium captured in the sampler and sampler, and the sampling efficiency is calculated based on the amount of tritium captured and the amount of tritium initially input. The steps that may cause errors in the above experimental measurement are: the method used to measure the standard tritium water with known activity concentration, whether the activity concentration given can truly reflect its tritium water concentration, which is uncertain; whether the sampler or sampler can capture all the tritiated water vapor produced, which is also uncertain; and finally, the measurement of the tritium amount by a liquid scintillation counter again has errors. Therefore, there are errors in multiple steps in the experimental measurement in the prior art, which leads to larger errors in the final sampling efficiency measurement results and poorer accuracy. In view of this problem, the present invention proposes a new sampling efficiency determination method, which generates water vapor through a water vapor generator to replace the use of standard tritium water with known activity concentration in the traditional experimental measurement process to generate tritiated water vapor through the bubbling method. This effectively avoids the problem of difficulty in tracing the activity concentration of standard tritium water, and also reduces the risk of contamination of the tritium sampler and sampler and leakage of tritiated water vapor HTO that may be caused in the process of using tritiated water vapor HTO gas source for efficiency measurement. In the present invention, the sampling efficiency is the ratio of the mass increased by the tritium sampler to the mass reduced by the water vapor generator. The present invention does not perform LSC measurement on the amount of tritium captured in the tritium sampler, which not only simplifies the operating steps, but also avoids the inevitable errors generated in the LSC measurement process. The present invention directly uses a calibrated analytical balance to measure the mass, which can further improve the accuracy of the sampling efficiency measurement.

[0036] In a further embodiment, the tritium sampler includes a plurality of absorption bottles, which are connected in series in sequence, and the first absorption bottle is connected to the water vapor generator through a gas pipeline.

[0037] In the present invention, multiple absorption bottles are arranged to be connected in series in sequence to form a multi-stage capture system. Each level of absorption bottles can capture a portion of the target gas (such as water vapor), thereby significantly improving the overall capture efficiency. Even if the first-stage absorption bottle fails to completely capture all the gas, the subsequent absorption bottles can continue to capture the remaining part to ensure that the sample loss is minimized. Multiple absorption bottles can better distribute the airflow and avoid the overload phenomenon caused by excessive flow in a single absorption bottle. By reasonably designing the volume and structure of each absorption bottle, the airflow can be evenly distributed in each absorption bottle to improve the capture effect. The multi-stage absorption system can effectively reduce the pulsation and fluctuation in the airflow, provide more stable sampling conditions, and ensure the accuracy of the measurement results. The design of multiple absorption bottles in the present invention can also make the entire sampling and measurement process easy to maintain and reduce errors. When a certain absorption bottle needs to be maintained or replaced, other absorption bottles can continue to work to ensure the continuous operation of the system. This modular design makes maintenance and overhaul more convenient and quick; through the capture results of multiple absorption bottles, more data points can be obtained for cross-validation. This helps to identify potential problems, such as a drop in the capture efficiency of a certain level of absorption bottle, and take timely measures to make adjustments. The multi-stage absorption system can reduce the accidental error caused by a single absorption bottle through multiple capture and measurement, and improve the reliability and accuracy of the measurement results.

[0038] In a further embodiment, the tritium sampler includes a first-stage absorption bottle and a second-stage absorption bottle connected in series in sequence, one end of the first-stage absorption bottle is connected to the water vapor generator through a gas pipe, the other end of the first-stage absorption bottle is connected to one end of the second-stage absorption bottle, and the other end of the second-stage absorption bottle is connected to an exhaust pipe, and a flow meter is provided on the exhaust pipe.

[0039] In a further embodiment, a vacuum pump and a flow regulating valve are arranged on the gas pipeline. Specifically, the gas pipeline is arranged between the water vapor generator and the first-stage absorption bottle, and a vacuum pump and a flow regulating valve are arranged in sequence along the gas flow direction.

[0040] The vacuum pump, flow regulating valve and flow meter in the present invention work together as a whole to regulate the flow in the gas circuit, wherein the vacuum pump can provide a stable pressure source to ensure that the gas passes through the absorption bottle at a constant speed, which helps to maintain the consistency of experimental conditions and reduce measurement errors caused by air flow fluctuations. By adjusting the power of the vacuum pump, the air flow speed can be controlled to be within the optimal range (such as 55 to 65 L / h), thereby improving the capture efficiency of the absorption bottle for the target gas (such as tritiated water vapor). The flow regulating valve can adjust the air flow size in real time according to the experimental requirements to ensure that each experiment can be carried out under the optimal flow conditions. For example, in different stages or different samples, the flow rate can be flexibly adjusted to meet different capture requirements. The flow meter can display the instantaneous flow in real time to help the operator understand the current air flow status at any time. The flow meter can also record the cumulative sampling flow rate and provide complete flow data for subsequent analysis and verification.

[0041] In a further embodiment, the absorption bottle is filled with ethylene glycol. Specifically, a gas pipeline at one end of the absorption bottle for introducing gas extends below the ethylene glycol liquid level, and a gas pipeline at one end for discharging gas is located above the ethylene glycol liquid level.

[0042] The ethylene glycol used in the present invention has a high solubility for water vapor and can effectively capture moisture in the gas, including tritiated water vapor (HTO). Compared with pure water, ethylene glycol can maintain a high solubility in a wider temperature range, ensuring that the target gas can be effectively captured under different environmental conditions. In addition, ethylene glycol has a high boiling point and is not easy to evaporate, which reduces the volatilization loss of the absorption liquid itself and ensures a long-term stable capture effect. Ethylene glycol is relatively environmentally friendly, and is relatively simple to handle and discharge, meets strict environmental protection standards, and reduces the risk of pollution to the environment.

[0043] It should also be noted that ethylene glycol is mainly used as a water vapor absorbent. As long as it can absorb water vapor, other absorbents can also be used in the present invention to replace ethylene glycol. Ethylene glycol is preferred in the present invention because, compared with some other organic solvents, ethylene glycol has lower toxicity and less impact on human health. During operation, even if a small amount of leakage occurs, it will not cause serious harm to the operator, thus improving the safety factor. In addition, ethylene glycol is relatively environmentally friendly, and its treatment and discharge are relatively simple, meeting strict environmental standards, and reducing the risk of environmental pollution.

[0044] In a further embodiment, the sampling flow rate includes the instantaneous flow rate and the cumulative sampling flow rate displayed by the flow meter, wherein the instantaneous flow rate is 55-65 L / h and the cumulative sampling flow rate is 0.5-2 m / h. 3 .

[0045] The present invention sets a specific instantaneous flow rate (55-65L / h) and a cumulative sampling flow rate (0.5-2m3 ), can ensure the consistency of experimental conditions and reduce the impact of external factors on the measurement results. By strictly controlling the flow parameters, more accurate and reliable sampling efficiency data can be obtained. At the same time, within this range, the absorption bottle can give full play to its capture capacity and ensure efficient capture of the target gas. The appropriate flow setting in the present invention can avoid incomplete capture caused by too fast airflow, or too long sample retention time caused by too slow airflow. By optimizing the flow parameters, sample loss can be minimized and capture efficiency can be improved.

[0046] In a further embodiment, the sampling efficiency is measured to be above 99% by a determination method.

[0047] The sampling efficiency of the present invention is above 99%, that is, almost all the target gas (such as water vapor) is effectively captured in the absorption bottle, which makes the measurement result more accurate and reduces the error caused by sample loss.

[0048] Example 1

[0049] Embodiment 1 of the present application provides a method for determining the sampling efficiency of a bubbling tritium sampler. In the process of determining the sampling efficiency of a bubbling tritium sampler, water vapor is generated by a water vapor generator to replace the use of standard tritium water with known activity concentration to generate tritiated water vapor HTO by bubbling method, which effectively avoids the problem of difficult traceability of the activity concentration of the generated tritiated water vapor HTO, and avoids the risk of contamination of the tritium sampler and sampler and leakage of tritiated water vapor HTO that may be caused by using the tritiated water vapor HTO gas source for efficiency determination. The sampling efficiency of the bubbling tritium sampler is obtained by weighing the water weight loss of the water vapor generator and the weight gain of the two-stage bubbler (absorption bottle) filled with ethylene glycol through the ratio between the two, which facilitates the determination of the sampling efficiency of the bubbling tritium sampler and sampler.

[0050] like Figure 1 As shown, this embodiment provides a method for determining the sampling efficiency of a bubbling tritium sampler, comprising the following steps:

[0051] A three-stage bubbler is connected in series, including a water vapor generator 1, a first-stage absorption bottle 4 and a second-stage absorption bottle 5. Pure water is contained in the water vapor generator 1 to generate water vapor during the heating process. The water vapor is introduced into the first-stage absorption bottle 4 as a gas source. One end of the first-stage absorption bottle 4 is connected to the water vapor generator 1 through a gas pipeline. The other end of the first-stage absorption bottle 4 is connected to one end of the second-stage absorption bottle 5. The other end of the second-stage absorption bottle 5 is connected to an exhaust pipeline. A flow meter 7 is provided on the exhaust pipeline. A vacuum pump 2 and a flow regulating valve 3 are arranged in sequence. The first-stage absorption bottle 4 and the second-stage absorption bottle 5 are both filled with ethylene glycol 6 absorption liquid. The gas pipeline at one end of the absorption bottle for introducing gas extends below the liquid level of ethylene glycol 6, and the gas pipeline at one end for discharging gas is located above the liquid level of ethylene glycol 6. The first absorption bottle 4 and the second-stage absorption bottle 5 are connected in series for continuous sampling. The gas flow of each gas path is adjusted by the vacuum pump 2, the flow regulating valve 3 and the flow meter 7. During the test, the instantaneous flow rate of sampling is 60L / h, and the cumulative sampling flow rate is 0.5m 3 , until the measurement is completed.

[0052] After the determination is completed, a calibrated balance is used to weigh the sample, and finally the weight loss of water in the water vapor generator 1 and the total weight gain of the first-stage absorption bottle 4 and the second-stage absorption bottle 5 filled with ethylene glycol absorption liquid are measured respectively. By using the ratio of the two, the collection efficiency of the two-stage absorption bottle in series for water vapor can be obtained, thereby testing the collection efficiency of the sampler for water vapor, and further verifying the collection efficiency of the sampler for tritiated water vapor.

[0053] Sampling efficiency = (weight gain of the first-stage absorption bottle + weight gain of the second-stage absorption bottle) / weight loss of the water vapor generator × 100%.

[0054] Example 2

[0055] The difference between this embodiment and embodiment 1 is that the cumulative sampling flow rate is different. The cumulative sampling flow rate in this embodiment is 1m 3 .

[0056] Example 3

[0057] The difference between this embodiment and embodiment 1 is that the cumulative sampling flow rate is different. The cumulative sampling flow rate in this embodiment is 1.5m 3 .

[0058] The sampling efficiency test data and results of Examples 1 to 3 are shown in Table 1.

[0059] Table 1

[0060]

[0061] It can be seen from Table 1 that the present invention can ensure a sampling efficiency of more than 99% under a specific sampling cumulative flow rate, indicating that the water vapor gas source generated by the water vapor generator is almost completely absorbed by the ethylene glycol in the first-stage absorption bottle and the second-stage absorption bottle, which significantly improves the sampling efficiency.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the sampling efficiency determination method adopted is different, and this comparative example adopts the traditional experimental measurement method.

[0064] Radioactive sampling and capture efficiency test method: Use three-stage bubblers connected in series to absorb and capture tritiated water vapor. The first, second and third bubblers are absorption bottles filled with deionized water absorption liquid for continuous sampling. Finally, liquid scintillation is used to measure the tritium counts in the three bubblers. The ratio of the tritium counts in the first two bubblers to the tritium counts in the third bubbler can be used to determine the capture efficiency of the two-stage bubblers in series for tritiated water vapor.

[0065] During the test, the instantaneous flow rate of sampling was 60L / h, and the cumulative sampling flow rate was 5m 3 Under the conditions, the water vapor sampling and collection efficiency is calculated. The test data is shown in Table 2

[0066] Table 2 3 H Sampling Efficiency Test Data

[0067]

[0068] Comparative Example 2

[0069] The difference between this comparative example and Example 1 is that the sampling efficiency determination method adopted is different, and this comparative example adopts the traditional theoretical calculation measurement method.

[0070] Theoretical calculation:

[0071] The HTO sampling efficiency of the bubbler was calculated and verified using the RVOsborne formula, which is shown in equations (1) and (2).

[0072] That is, the collection efficiency of HTO by the first-stage bubbling bottle is:

[0073]

[0074] The collection efficiency of HTO by the second-stage bubbling bottle is:

[0075]

[0076] Where: Assuming the relative humidity of the bubbler gas is H, then X is the moisture content of air (g / m 3 ); Y is the saturated water content of air at the sampling temperature (g / m 3 ) ; ε is the saturation coefficient, which refers to the percentage of tritiated water vapor contained in the bubbled air absorbed by the water in the bubbler; V is the volume of sampled air; α is the isotope effect coefficient, A1 is the radioactivity in the first-stage bubbler (Bq); A2 is the radioactivity in the second-stage bubbler (Bq); C is the concentration of tritiated water vapor HTO (Bq / m 3 ); m0 is the initial filling amount of the collecting liquid in the bubbler; m is the remaining amount of the collecting liquid in the bubbler; X is the water content of the gas entering the bubbler.

[0077] By taking the saturation coefficient ε of the bubbler as 1 and the isotope effect coefficient α as 0.88 under the conditions of temperature of 20.6°C and relative humidity of 50%, the isotope effect coefficient increases with the increase of temperature. However, in the actual instrument sampling work, the temperature of the bubbler is basically between 0°C and 30°C, so the average value of 0.88 is taken. The calculation results are shown in Table 3.

[0078] Table 3 3 Theoretical calculation value of H sampling efficiency

[0079] Sampling temperature (℃) Primary bubbler efficiency (%) Secondary bubbler efficiency (%) 20.6 76.2 96.6

[0080] It can be seen from Table 2 and Table 3 that, whether using traditional experimental measurement or theoretical calculation, the sampling efficiency is lower than the sampling efficiency measured by the weighing method in the present invention, which shows that the determination method of the present invention can avoid many errors existing in the prior art and further improve the measurement accuracy.

[0081] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for determining the sampling efficiency of a bubbling tritium sampler, characterized in that: The method comprises the following steps: the gas generated by the water vapor generator is introduced into a tritium sampler, the tritium sampler comprises a plurality of absorption bottles, the absorption bottles are filled with absorbent, the plurality of absorption bottles are connected in series in sequence, the first absorption bottle is connected with the water vapor generator through a gas pipeline, the gas pipeline is provided with a vacuum pump and a flow regulating valve, the sampling flow in the gas circuit is controlled by a flow meter, and after the sampling is completed, the sampling efficiency is the ratio of the mass increased by the tritium sampler to the mass reduced by the water vapor generator.

2. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 1, characterized in that: The tritium sampler includes a first-stage absorption bottle and a second-stage absorption bottle connected in series in sequence. One end of the first-stage absorption bottle is connected to a water vapor generator through a gas pipeline, the other end of the first-stage absorption bottle is connected to one end of the second-stage absorption bottle, and the other end of the second-stage absorption bottle is connected to an exhaust pipeline, on which a flow meter is arranged.

3. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 1, characterized in that: The absorbent is ethanol.

4. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 1, characterized in that: The sampling flow rate includes the instantaneous flow rate displayed by the flow meter and the cumulative sampling flow rate, where the instantaneous flow rate is 55-65L / h and the cumulative sampling flow rate is 0.5-2m 3 .

5. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 4, characterized in that: The instantaneous flow rate is 60L / h and the cumulative sampling flow rate is 1.5m 3 .

6. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 2, characterized in that: Sampling efficiency = (weight gain of the first-stage absorption bottle + weight gain of the second-stage absorption bottle) / weight loss of the water vapor generator × 100%.

7. The method for determining the sampling efficiency of a bubbling tritium sampler according to claim 1, characterized in that: The sampling efficiency was found to be above 99%.

8. A bubbling tritium sampler sampling device, characterized in that: It includes a water vapor generator and a tritium sampler. The tritium sampler includes a plurality of absorption bottles, which are connected in series in sequence. The first absorption bottle is connected to the water vapor generator through a gas pipeline, and the last absorption bottle is connected to an exhaust pipeline.

9. The bubbling tritium sampler sampling device according to claim 8, characterized in that: A gas pump and a flow regulating valve are sequentially arranged on the gas pipeline along the gas flow direction, and a flow meter is arranged on the exhaust pipeline.

10. The bubbling tritium sampler sampling device according to claim 8, characterized in that: One end of the gas pipeline for introducing gas into the absorption bottle extends to below the ethylene glycol liquid surface, and one end of the gas pipeline for discharging gas is located above the ethylene glycol liquid surface.

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