Tritium release rate measuring method

Abstract

The invention provides a tritium release rate measuring method. The method comprises the following steps: obtaining a silica gel sample adsorbing water vapor released by a cement solidified body; obtaining background water according to a preset preparation mode; obtaining a mixture according to the silica gel sample and the background water; the mixture is leached, and a mixed leaching solution is obtained; obtaining a blank counting rate and a tritium standard solution counting rate according to the background water and the tritium standard solution; determining the tritium activity concentration in the silica gel sample according to the mixed leaching solution, a preset scintillation solution, the blank counting rate and the tritium standard solution counting rate; determining the leaching rate according to the dry silica gel and the tritium standard solution; and determining the tritium release rate according to the tritium activity concentration in the silica gel sample and the leaching rate. The method can accurately and reliably monitor the release rate of tritium in the cement solidified body, and has the advantages of simple operation, low cost and high working efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of tritium release rate measurement, and also relates to a method for measuring the tritium release rate. Background Art

[0002] Cement solidified body is a stable solid form formed by uniformly fixing radionuclides in a stable cement solidified body medium for long-term storage and safe transportation. Tritium is a radioactive isotope with potential hazards. Measuring the tritium release rate of cement solidified body helps to evaluate its safety and understand the potential risks to the environment and human body. By measuring the release rate, it can be determined whether the solidified body can effectively fix tritium and prevent it from leaking into the environment. In order to confirm the tritium release rate in the cement solidified body, in the prior art, generally, silica gel is used to adsorb tritium released from the cement solidified body in a closed container and convert it all into tritiated water (HTO and T2O); for silica gel samples, the vacuum heating desorption method is mostly used, which requires a special heating device and has a long operation time and low working efficiency. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for measuring the tritium release rate to improve the measurement efficiency of the tritium release rate of cement solidified body.

[0004] To solve the above technical problem, the technical solution of the present invention is as follows:

[0005] The present invention provides a method for measuring the tritium release rate, including:

[0006] Obtaining a silica gel sample adsorbed with water vapor released from a cement solidified body;

[0007] Obtaining background water according to a preset preparation method;

[0008] Obtaining a mixture according to the silica gel sample and the background water;

[0009] Performing leaching on the mixture to obtain a mixed leaching solution;

[0010] Obtaining a blank counting rate and a tritium standard solution counting rate according to the background water and a tritium standard solution;

[0011] Determining the tritium activity concentration in the silica gel sample according to the mixed leaching solution, a preset scintillation solution, the blank counting rate, and the tritium standard solution counting rate;

[0012] Determining the leaching rate according to dry silica gel and a tritium standard solution;

[0013] Determining the tritium release rate according to the tritium activity concentration in the silica gel sample and the leaching rate.

[0014] Optionally, obtaining a silica gel sample adsorbed with water vapor released from a cement solidified body includes:

[0015] Drying the silica gel according to preset drying parameters to obtain the dried silica gel;

[0016] Placing the dried silica gel in a closed space filled with a cement solidified body for water vapor adsorption according to preset adsorption parameters to obtain a silica gel sample.

[0017] Optionally, obtaining background water according to a preset preparation method includes:

[0018] Obtaining deep groundwater according to preset volume-taking parameters;

[0019] Performing distillation treatment on the deep groundwater according to preset distillation parameters to obtain distilled water;

[0020] Obtaining background water based on a preset preparation method, a preset value, and the distilled water; the tritium counting rate in the background water conforms to the preset value.

[0021] Optionally, obtaining a mixture based on the silica gel sample and the background water includes:

[0022] Crushing the silica gel sample to obtain silica gel powder;

[0023] Obtaining a mixture based on the silica gel powder and the background water.

[0024] Optionally, leaching the mixture to obtain a mixed leaching solution includes:

[0025] Adding 100 mL of the background water along the wall of the reagent bottle containing the mixture and stirring evenly to obtain a test sample;

[0026] Performing ultrasonic leaching on the test sample according to preset leaching parameters to obtain a leaching solution;

[0027] Washing the test sample in the reagent bottle with background water to obtain a washing solution;

[0028] Mixing the leaching solution and the washing solution evenly to obtain a mixed leaching solution.

[0029] Optionally, obtaining a blank counting rate and a tritium standard solution counting rate based on the background water and a tritium standard solution includes:

[0030] Measuring the background water with a liquid scintillation spectrometer to obtain a blank counting rate;

[0031] Measuring the tritium standard solution with a liquid scintillation spectrometer to obtain a tritium standard solution counting rate.

[0032] Optionally, determining the tritium activity concentration in the silica gel sample according to the mixed leaching solution, the preset scintillation solution, the blank counting rate, and the tritium standard solution counting rate includes:

[0033] Mixing the mixed leaching solution and the preset scintillation solution to obtain a sample to be measured;

[0034] Measuring the sample to be measured by a liquid scintillation spectrometer to obtain a sample counting rate;

[0035] Determining the tritium activity concentration in the silica gel sample according to the sample counting rate, the sample to be measured, the blank counting rate, and the tritium standard solution counting rate.

[0036] Optionally, determining the tritium activity concentration in the silica gel sample according to the sample counting rate, the sample to be measured, the blank counting rate, and the tritium standard solution counting rate includes:

[0037] According to the sample counting rate, the sample to be measured, the blank counting rate, the tritium standard solution counting rate, and Determining the tritium activity concentration in the silica gel sample;

[0038] where C is the tritium activity concentration in the silica gel sample, N c is the sample counting rate, N0 is the blank counting rate, A is the tritium standard solution activity, V is the constant volume, V1 is the sampling volume of the sample to be measured, N s is the tritium standard solution counting rate.

[0039] Optionally, determining the extraction rate according to the dry silica gel and the tritium standard solution includes:

[0040] Placing the dry silica gel above the tritium standard solution so that the dry silica gel adsorbs the tritium gas released by the tritium standard solution to obtain the tritium activity concentration adsorbed by the silica gel;

[0041] According to the tritium activity concentration adsorbed by the silica gel, the tritium activity concentration in the silica gel sample, and Determining the extraction rate;

[0042] where η1 is the extraction rate, C is the tritium activity concentration in the silica gel sample, and C1 is the tritium activity concentration adsorbed by the silica gel.

[0043] Optionally, determining the tritium release rate according to the tritium activity concentration in the silica gel sample and the extraction rate includes: According to the tritium activity concentration in the silica gel sample, the extraction rate, and Determining the tritium release rate;

[0044] where η2 is the tritium release rate, C is the tritium activity concentration in the silica gel sample, C2 is the total tritium content in the cement solidified body, and η1 is the extraction rate.

[0045] The above - mentioned solution of the present invention has at least the following beneficial effects:

[0046] In the above - mentioned solution of the present invention, by using a silica gel sample adsorbed with water vapor released from a cement solidified body and obtaining background water according to a preset preparation method, a mixture is obtained. The mixture is leached to obtain a mixed leaching solution. According to the background water and a tritium standard solution, a blank counting rate and a tritium standard solution counting rate are obtained. Then, the tritium activity concentration in the silica gel sample is calculated. Then, according to the dry silica gel and the tritium standard solution, the leaching rate is determined. Finally, the tritium release rate can be calculated, realizing accurate and reliable monitoring of the tritium release rate in the cement solidified body, and having the advantages of simple method operation, low cost and high working efficiency. Description of the Drawings

[0047] Figure 1 It is a schematic flow chart of the method for measuring the tritium release rate in an embodiment of the present invention. Detailed Embodiments

[0048] Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be completely conveyed to those skilled in the art.

[0049] As Figure 1 shown, an embodiment of the present invention provides a method for measuring the tritium release rate, including the following steps:

[0050] Step 101: Obtain a silica gel sample adsorbed with water vapor released from a cement solidified body;

[0051] Step 102: Obtain background water according to a preset preparation method;

[0052] Step 103: Obtain a mixture according to the silica gel sample and the background water;

[0053] Step 104: Leach the mixture to obtain a mixed leaching solution;

[0054] Step 105: Obtain a blank counting rate and a tritium standard solution counting rate according to the background water and a tritium standard solution;

[0055] Step 106: Determine the tritium activity concentration in the silica gel sample according to the mixed leaching solution, a preset scintillation solution, the blank counting rate and the tritium standard solution counting rate;

[0056] Step 107: Determine the leaching rate according to the dry silica gel and the tritium standard solution;

[0057] Step 108: Determine the tritium release rate based on the tritium activity concentration in the silica gel sample and the extraction rate.

[0058] In the tritium release rate measurement method according to the embodiments of the present invention, by using a silica gel sample adsorbed with water vapor released from a cement solidified body and obtaining background water according to a preset preparation method to obtain a mixture, extracting the mixture to obtain a mixed extraction solution, obtaining a blank counting rate and a tritium standard solution counting rate based on the background water and the tritium standard solution, and then calculating the tritium activity concentration in the silica gel sample. Then, determine the extraction rate according to the dry silica gel and the tritium standard solution. Finally, the tritium release rate can be calculated, realizing accurate and reliable monitoring of the tritium release rate in the cement solidified body. It has the advantages of simple method operation, low cost, and high working efficiency.

[0059] In an optional embodiment of the present invention, step 101 includes:

[0060] Step 1011: Dry the silica gel according to preset drying parameters to obtain dried silica gel.

[0061] Specifically, the preset drying parameters include: a drying temperature of 300 to 400 °C and a drying time of 2 to 4 hours. Here, take 200 g to 500 g of anhydrous dry silica gel with a mesh size of 20 to 40 and a uniform pore structure, remove oversized or undersized particles by screening, and dry at 300 to 400 °C for 2 to 4 hours to obtain dried silica gel, ensuring the consistency of adsorption sites and avoiding uneven adsorption problems.

[0062] Step 1012: Place the dried silica gel in a closed space containing a cement solidified body for water vapor adsorption according to preset adsorption parameters to obtain a silica gel sample.

[0063] Specifically, encapsulate the dried silica gel with a dressing bag having good air permeability and place it at the central position of a closed box containing a cement solidified body to adsorb the water vapor released from the cement solidified body. After 30 days, collect the silica gel sample into a sealed bottle for encapsulation (to prevent the evaporation of the water adsorbed by the silica gel) as the silica gel sample.

[0064] In an optional embodiment of the present invention, step 102 includes:

[0065] Step 1021: Obtain deep groundwater according to preset volume-taking parameters.

[0066] Specifically, the preset volume-taking parameters include: a volume of 500 mL, a filter membrane pore size of 0.45 μm, and a liquid loading not exceeding 2 / 3 of the container. In a specific embodiment, measure 500 mL of deep groundwater, remove suspended particles through a 0.45 μm filter membrane and transfer it to a borosilicate glass round-bottom flask, with the liquid loading not exceeding 2 / 3 of the flask to avoid bumping.

[0067] Step 1022: Distill the deep groundwater according to preset distillation parameters to obtain distilled water.

[0068] Specifically, the preset distillation parameters include: a distillation speed of 1 to 2 drops per second, and repeated distillation 3 to 5 times, etc. In a specific embodiment, the round-bottomed borosilicate glass bottle containing deep groundwater is covered with a ground glass stopper, and a snake-shaped condenser is installed. Then, start atmospheric distillation using an electric heating mantle, control the heating rate to make the distillation speed 1 to 2 drops per second to reduce the isotope fractionation effect. The first 50 mL of distillate may contain volatile impurities and needs to be discarded. Collect 400 mL of the middle-section distillate in a beaker. Repeat the distillation of the middle-section distillate 3 to 5 times, and discard the initial distillate and residual liquid each time to gradually reduce the tritium content.

[0069] Step 1023: Obtain background water according to a preset preparation method, preset value, and the distilled water; the counting rate of tritium in the background water meets the preset value.

[0070] Specifically, the counting rate of tritium in each distillate needs to be measured by a liquid scintillation spectrometer (the counting rate of tritium refers to the number of tritium radioactive decay events measured per unit time). After the counting rate of tritium meets the preset value, store it in a glass bottle or PTFE (polytetrafluoroethylene) bottle that has been pickled and heat-treated to obtain background water.

[0071] In an alternative embodiment of the present invention, step 103 includes:

[0072] Step 1031: Crush the silica gel sample to obtain silica gel powder.

[0073] Specifically, to improve the leaching rate of tritium in the silica gel sample, the silica gel sample can be crushed into powder, but grinding is not allowed to prevent the volatilization of moisture during the grinding process, resulting in a low measurement result.

[0074] Step 1032: Obtain a mixture according to the silica gel powder and the background water.

[0075] Specifically, weigh 50 g of silica gel powder, add a preset volume of background water, and use a pulverizer to crush it into a mixture of silica gel powder and water, and then transfer it all to a reagent bottle to obtain a mixture.

[0076] In an alternative embodiment of the present invention, step 104 includes:

[0077] Step 1041: Add 100 mL of the background water along the wall of the reagent bottle containing the mixture and stir evenly to obtain a test sample.

[0078] Step 1042: Perform ultrasonic extraction on the test sample according to preset extraction parameters to obtain an extraction solution.

[0079] Step 1043: Wash the sample in the reagent bottle with background water to obtain a washing solution.

[0080] Step 1044: Mix the leaching solution and the washing solution evenly to obtain a mixed leaching solution.

[0081] Specifically, in a reagent bottle containing a mixture of silica gel powder and water, quickly add 100 mL of background water along the inner wall of the cup and stir evenly to obtain a sample. Ultrasonically leach the sample for 1 h under sealed conditions at 80 °C to 90 °C, filter, and collect all the leaching solutions. Repeat this operation twice. Then, wash the silica gel powder in the reagent bottle with a small amount of background water, and mix the leaching solutions and the washing solution collected twice evenly, and make up the volume to a 250 mL volumetric flask as the mixed leaching solution.

[0082] In an alternative embodiment of the present invention, step 105 includes:

[0083] Step 1051: Measure the background water with a liquid scintillation spectrometer to obtain a blank counting rate.

[0084] Step 1052: Measure the tritium standard solution with a liquid scintillation spectrometer to obtain a tritium standard solution counting rate.

[0085] Specifically, put the background water and the tritium standard solution (a tritium standard solution sample with a known radioactivity) into a liquid scintillation spectrometer and measure indoors. The measurement results are used as the blank counting rate and the tritium standard solution counting rate.

[0086] In an alternative embodiment of the present invention, step 106 includes:

[0087] Step 1061: Mix the mixed leaching solution and a preset scintillation solution to obtain a sample to be measured.

[0088] Step 1062: Measure the sample to be measured with a liquid scintillation spectrometer to obtain a sample counting rate.

[0089] Specifically, collect 2 mL of the multiple ultrasonic leaching solutions (i.e., the mixed leaching solution) and mix it with 15 mL of the scintillation solution (a scintillator mixture for liquid scintillation counting measurement). After standing in the dark for 2.5 h, measure with a liquid scintillation spectrometer to obtain the sample counting rate.

[0090] Step 1063: Determine the tritium activity concentration in the silica gel sample according to the sample counting rate, the sample to be measured, the blank counting rate, and the tritium standard solution counting rate.

[0091] In an alternative embodiment of the present invention, step 1063 includes:

[0092] According to the sample counting rate, the sample to be measured, the blank counting rate, the tritium standard solution counting rate, and Determine the tritium activity concentration in the silica gel sample;

[0093] Wherein, C is the tritium activity concentration in the silica gel sample, N c is the sample counting rate, N0 is the blank counting rate, A is the activity of the tritium standard solution, V is the fixed volume, V1 is the sampling volume of the sample to be measured, N s is the counting rate of the tritium standard solution.

[0094] In an alternative embodiment of the present invention, step 107 includes:

[0095] Step 1071: Place the dried silica gel above the tritium standard solution so that the dried silica gel adsorbs the tritium gas released by the tritium standard solution, obtaining dried silica gel adsorbed with tritium gas and the tritium activity concentration adsorbed by the silica gel;

[0096] Specifically, measure 6 portions of 100 mL of the tritium standard solution into beakers, and place them respectively in a closed space containing 50 g of dried silica gel (accurate to 0.2 mg). Control the temperature and humidity of the closed space (temperature is 20 °C to 30 °C, humidity is < 30% RH) to allow the tritium standard solution to slowly release, and make it all adsorbed in the dried silica gel. Then weigh its weight after adsorption, and calculate the tritium activity concentration adsorbed by the silica gel.

[0097] Step 1072: Leach the dried silica gel adsorbed with tritium gas to obtain the tritium activity concentration in the silica gel sample;

[0098] Specifically, crush the dried silica gel adsorbed with tritium gas in step 1071 and transfer it to a reagent bottle. Quickly add 100 mL of background water along the wall of the cup and stir evenly. Conduct two leaching operations and one washing. Mix the washing liquid with the two leaching liquids and measure the tritium content to obtain the tritium activity concentration in the silica gel sample. It should be noted that the formula for calculating the tritium activity concentration in the silica gel sample in this step can be the same as that in step 1063.

[0099] Step 1073: Determine the leaching rate according to the tritium activity concentration adsorbed by the silica gel, the tritium activity concentration in the silica gel sample, and Determine the leaching rate.

[0100] Wherein, η1 is the leaching rate, C is the tritium activity concentration in the silica gel sample, C1 is the tritium activity concentration adsorbed by the silica gel, and is obtained from the tritium standard with a known activity.

[0101] In an alternative embodiment of the present invention, step 108 includes:

[0102] According to the tritium activity concentration in the silica gel sample, the leaching rate, and Determine the tritium release rate;

[0103] Among them, η2 is the tritium release rate, C is the tritium activity concentration in the silica gel sample, C2 is the total tritium content in the cement solidified body, and η1 is the leaching rate.

[0104] In the method for measuring the tritium release rate according to the embodiment of the present invention, by utilizing the characteristic that silica gel has strong water absorption, when an air flow containing tritiated water vapor flows through the silica gel for sampling or the silica gel is directly exposed to the air, the tritiated water vapor will be adsorbed by the silica gel together with ordinary water vapor, achieving the purpose of sampling. After sampling, the tritium in the silica gel sample is displaced into the leaching solution through multiple ultrasonic leaching. The leaching solution and the scintillation solution are mixed in a certain proportion. The energy of the β-rays emitted by tritium in the sample to be tested is absorbed by the solvent in the scintillation solution and transmitted to the scintillator molecules. The visible light photons emitted by the de-excitation of the scintillator molecules are detected by the photomultiplier tube in the liquid scintillation counter, so as to measure the counting rate of tritium in the silica gel sample. After blank and detection efficiency correction, the tritium activity concentration in the silica gel is obtained, and then the tritium release rate is calculated.

[0105] A specific embodiment of the method for measuring the tritium release rate according to the embodiment of the present invention includes:

[0106] Step 111, obtaining a silica gel sample;

[0107] Take 200 g to 500 g of anhydrous dry silica gel with a mesh number of 20 to 40 and a uniform pore structure. Remove oversized or undersized particles by sieving, and dry at 300 to 400 °C for 2 to 4 hours to ensure the consistency of adsorption sites and avoid uneven adsorption problems. Package the dried silica gel with a dressing bag having good air permeability and place it at the central position of a sealed box containing the cement solidified body to adsorb the water vapor released by the cement solidified body. After 30 days, collect the silica gel sample into a sealed bottle for packaging (to prevent the evaporation of the water adsorbed by the silica gel), and use it as the silica gel sample.

[0108] Step 112, obtaining background water;

[0109] Measure 500 mL of deep groundwater, remove suspended particles through a 0.45 μm filter membrane and transfer it to a borosilicate glass round-bottom flask. The liquid filling amount does not exceed 2 / 3 of the container to avoid bumping. Cover the ground glass stopper, install a snake-shaped condenser and start atmospheric distillation using an electric heating mantle. Control the heating rate so that the distillation speed is 1 to 2 drops / second to reduce the isotope fractionation effect. The first 50 mL of the distillate may contain volatile impurities and needs to be discarded. Collect 400 mL of the middle distillate in a beaker. Repeat the distillation of the middle distillate 3 to 5 times. Each time, discard the initial distillate and the residual liquid to gradually reduce the tritium content. The tritium counting rate of each distillate needs to be measured by a liquid scintillation spectrometer. After the tritium counting rate meets the preset value, store it in a glass bottle or a PTFE (polytetrafluoroethylene) bottle that has been pickled and heat-treated as the background water.

[0110] Step 113, preparing a mixture;

[0111] To improve the leaching rate of tritium in the silica gel sample, the silica gel sample particles can be crushed into powder, but grinding is not allowed to prevent the volatilization of moisture during the grinding process, which may cause the measurement result to be on the low side. Weigh 50 g of silica gel powder, add a preset volume of background water, and use a pulverizer to crush it into a mixture of silica gel powder and water, then transfer all of it to a 200 mL reagent bottle.

[0112] Step 114, prepare the mixed leaching solution;

[0113] Single ultrasonic leaching. In the reagent bottle containing the mixture of silica gel powder and water, accurately pipette 100 mL of background water with a volumetric flask, quickly pour it along the inner wall of the cup into the reagent bottle and stir evenly. Cover the reagent bottle cap to ensure that the reagent bottle is in a sealed state to prevent the loss of tritium during the leaching process. Place the sealed reagent bottle in a water bath and perform ultrasonic leaching at 80 °C to 90 °C for 1 h, then filter and collect the first leaching solution.

[0114] Double ultrasonic leaching. Add another 100 mL of background water to the reagent bottle containing the mixture of silica gel powder and water, perform ultrasonic leaching at 80 °C to 90 °C for 1 h, and collect the second leaching solution.

[0115] Washing of the mixture. To prevent the measurement result from being on the low side due to the residual tritium on the surface of the reagent bottle, add 30 mL of background water to the reagent bottle containing the mixture of silica gel powder and water to wash the residual tritium on the surface of the reagent bottle, then filter and collect the washing solution.

[0116] Prepare the mixed leaching solution. Mix the two collected leaching solutions and rinsing solutions evenly, and make up the volume to a 250 mL volumetric flask as the mixed leaching solution.

[0117] Step 115, determine the blank counting rate and the counting rate of the tritium standard solution;

[0118] Take 2 mL of background water and tritium standard solution, mix them with 15 mL of scintillation solution, let it stand in the dark for 2.5 h, and then measure with a liquid scintillation spectrometer to obtain the blank counting rate and the counting rate of the tritium standard solution.

[0119] Step 116, determine the tritium activity concentration in the silica gel sample;

[0120] Mix 2 mL of the mixed leaching solution and 15 mL of scintillation solution, let it stand in the dark for 2.5 h as the sample to be measured, and measure with a liquid scintillation spectrometer to obtain the sample counting rate.

[0121] Input the sample counting rate, the sample weighing amount (the mass of the sample to be measured) of the sample to be measured, the blank counting rate, and the counting rate of the tritium standard solution into the formula Calculate to obtain the tritium activity concentration in the silica gel sample.

[0122] Among them, C is the tritium activity concentration in the silica gel sample, Bq (when expressed in Bq / g, it can be obtained by dividing by the weighed sample amount of the sample to be measured), N c is the sample counting rate, with the unit of cpm, N0 is the blank counting rate, with the unit of cpm, A is the tritium standard solution activity (obtained from the tritium standard solution with a known activity), with the unit of Bq, V is the fixed volume, with the unit of L, V1 is the sampling volume of the sample to be measured, with the unit of L, N s is the tritium standard solution counting rate.

[0123] Step 117, determine the leaching rate;

[0124] Weigh 6 portions of 50 g of dry silica gel above the tritium standard (accurate to 0.2 mg), allow it to adsorb the tritium gas released by the tritium standard and weigh it, and the tritium activity concentration adsorbed by the silica gel can be calculated; after the dry silica gel adsorbed with tritium gas is crushed, it is all transferred to a 200 mL reagent bottle, quickly add 100 mL of background water along the wall of the cup and stir evenly, perform ultrasonic leaching at 80 °C to 90 °C for 1 h, filter and collect the first leaching solution, add 100 mL of background water to the reagent bottle again, perform ultrasonic leaching at 80 °C to 90 °C for 1 h, and collect the second leaching solution. Add 30 mL of background water to the reagent bottle to wash the tritium remaining on the surface of the reagent bottle, filter and collect the washing solution. Mix the two collected leaching solutions and rinsing solutions evenly and fix the volume to a 250 mL volumetric flask, then measure the tritium content and calculate the leaching rate.

[0125] Here, the leaching rate can be determined through the tritium activity concentration adsorbed by the silica gel, the tritium activity concentration in the silica gel sample, and Determine the leaching rate; among them, η1 is the leaching rate, C is the tritium activity concentration in the silica gel sample, Bq, C1 is the tritium activity concentration adsorbed by the silica gel, Bq.

[0126] Step 118, determine the tritium release rate.

[0127] According to the tritium activity concentration in the silica gel sample, the leaching rate, and Determine the tritium release rate; among them, η2 is the tritium release rate, C is the tritium activity concentration in the silica gel sample, Bq, C2 is the total tritium content in the cement solidified body, Bq, η1 is the leaching rate.

[0128] The method for measuring the tritium release rate in the embodiments of the present invention utilizes the high adsorption efficiency of silica gel and its strong water absorption. By using silica gel, all the tritium released from the cement solidified body can be adsorbed and collected. At the same time, through the pretreatment method of ultrasonic extraction with background water multiple times, the adsorbed tritium is converted into tritiated water, realizing accurate and reliable monitoring of the tritium release rate in the cement solidified body. This method is applicable to various tritium-containing solids, including but not limited to environmental samples, nuclear fuel samples, etc., and has a wide application range. The background water is easy to obtain and has a low cost. The treatment method of ultrasonic extraction multiple times only requires conventional laboratory equipment, which is relatively simple, easy for on-site personnel to master and implement, has good operability, can extract multiple samples simultaneously, is suitable for large-scale sample analysis, and has the advantages of low cost and simple operation.

[0129] It should be noted that in the above embodiments, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element. In addition, it should be pointed out that the scope of the methods and devices in the above embodiments of the implementation manner is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described method may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, the features described with reference to certain examples may be combined in other examples.

[0130] The above is the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art in the technical field of the present invention, without departing from the principle described in the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for measuring the tritium release rate, characterized in that, including: obtaining a silica gel sample adsorbed with water vapor released from a cement solidified body; obtaining background water according to a preset preparation method; obtaining a mixture based on the silica gel sample and the background water; performing leaching on the mixture to obtain a mixed leaching solution; obtaining a blank counting rate and a tritium standard solution counting rate based on the background water and a tritium standard solution; determining the tritium activity concentration in the silica gel sample based on the mixed leaching solution, a preset scintillation solution, the blank counting rate, and the tritium standard solution counting rate; determining the leaching rate based on dry silica gel and a tritium standard solution; determining the tritium release rate based on the tritium activity concentration in the silica gel sample and the leaching rate.

2. The measurement method of the tritium release rate according to claim 1, characterized in that, Obtaining a silica gel sample adsorbed with water vapor released from a cement solidified body includes: performing a drying treatment on silica gel according to preset drying parameters to obtain dried silica gel; placing the dried silica gel in a closed space containing a cement solidified body for water vapor adsorption according to preset adsorption parameters to obtain a silica gel sample.

3. The method for measuring the tritium release rate according to claim 1, characterized in that, Obtaining background water according to a preset preparation method includes: obtaining deep groundwater according to preset volume-taking parameters; performing a distillation treatment on the deep groundwater according to preset distillation parameters to obtain distilled water; obtaining background water based on a preset preparation method, a preset value, and the distilled water; the counting rate of tritium in the background water conforms to the preset value.

4. The measurement method of tritium release rate according to claim 1, characterized in that, Obtaining a mixture based on the silica gel sample and the background water includes: performing a pulverization treatment on the silica gel sample to obtain silica gel powder; obtaining a mixture based on the silica gel powder and the background water.

5. The measurement method of tritium release rate according to claim 1, wherein Performing leaching on the mixture to obtain a mixed leaching solution includes: adding 100 mL of the background water along the wall of a reagent bottle containing the mixture and stirring evenly to obtain a test sample; performing ultrasonic leaching on the test sample according to preset leaching parameters to obtain a leaching solution; washing the test sample in the reagent bottle with background water to obtain a washing solution; mixing the leaching solution and the washing solution evenly to obtain a mixed leaching solution.

6. The method for measuring the tritium release rate according to claim 1, wherein, Obtaining a blank counting rate and a tritium standard solution counting rate based on the background water and a tritium standard solution includes: measuring the background water by a liquid scintillation spectrometer to obtain a blank counting rate; measuring the tritium standard solution by a liquid scintillation spectrometer to obtain a tritium standard solution counting rate.

7. The method for measuring the tritium release rate according to claim 1, wherein Determining the tritium activity concentration in the silica gel sample based on the mixed leaching solution, a preset scintillation solution, the blank counting rate, and the tritium standard solution counting rate includes: mixing the mixed leaching solution and a preset scintillation solution to obtain a sample to be measured; measuring the sample to be measured by a liquid scintillation spectrometer to obtain a sample counting rate; determining the tritium activity concentration in the silica gel sample based on the sample counting rate, the sample to be measured, the blank counting rate, and the tritium standard solution counting rate.

8. The method for measuring the tritium release rate according to claim 7, characterized in that, Determining the tritium activity concentration in the silica gel sample based on the sample counting rate, the sample to be measured, the blank counting rate, and the tritium standard solution counting rate includes: Based on the sample counting rate, the sample to be measured, the blank counting rate, the tritium standard solution counting rate, and determine the tritium activity concentration in the silica gel sample; Where C is the tritium activity concentration in the silica gel sample, N c is the sample counting rate, N0 is the blank counting rate, A is the activity of the tritium standard solution, V is the fixed volume, V1 is the sampling volume of the sample to be measured, and N s is the counting rate of the tritium standard solution.

9. The measurement method of tritium release rate according to claim 1, characterized in that, Determining the leaching rate based on dry silica gel and a tritium standard solution includes: placing dry silica gel above a tritium standard solution so that the dry silica gel adsorbs the tritium gas released from the tritium standard solution to obtain the tritium activity concentration adsorbed by the silica gel; Determine the leaching rate according to the tritium activity concentration adsorbed by the silica gel, the tritium activity concentration in the silica gel sample, and ​ Among them, η1 is the leaching rate, C is the tritium activity concentration in the silica gel sample, and C1 is the tritium activity concentration adsorbed by the silica gel.

10. The method for measuring the tritium release rate according to claim 1, wherein Determine the tritium release rate according to the tritium activity concentration in the silica gel sample and the leaching rate, including: according to the tritium activity concentration in the silica gel sample, the leaching rate and Determine the tritium release rate; Among them, η2 is the tritium release rate, C is the tritium activity concentration in the silica gel sample, C2 is the total tritium content in the cement solidified body, and η1 is the leaching rate.

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