Uranium hexafluoride gas diffusion coefficient measuring device and method

Abstract

The invention provides a uranium hexafluoride gas diffusion coefficient measuring device and method, and the device comprises a first constant-pressure pipe, valves are installed close to the two ends of the first constant-pressure pipe, and a first opening is formed in the first constant-pressure pipe between the valves; one end of the diffusion pipe is connected with the first opening of the first constant pressure pipe; a second opening is formed in the diffusion pipe and is used for being externally connected with a sampling device; valves are mounted close to the two ends of the second constant-pressure pipe respectively, a third opening is formed in the second constant-pressure pipe located between the valves, and the third opening is connected with the other end of the diffusion pipe; the plurality of flowmeters are respectively arranged on outer side pipelines, close to the valves, of the first constant-pressure pipe and the second constant-pressure pipe; the plurality of pressure gauges are respectively arranged on inner side pipelines, close to the valve, of the first constant-pressure pipe and the second constant-pressure pipe; and electric heat tracing equipment is arranged outside the first constant-pressure pipe, the diffusion pipe and the second constant-pressure pipe.

Description

Technical Field

[0001] The invention relates to the field of nuclear fuel technology, and in particular to a device and method for measuring the uranium hexafluoride gas diffusion coefficient. Background Art

[0002] In the field of nuclear fuel, the raw material uranium hexafluoride (UF6) is contained in international standard containers. UF6 is colorless or light yellow crystals at room temperature and pressure. During the nuclear fuel cycle, the solid uranium hexafluoride contained in the container is gasified and fed. The diffusion coefficient is an important parameter to characterize the diffusion ability of a substance and is one of the physical properties of a substance. According to Fick's law, the diffusion coefficient is the mass or mole of a substance diffused vertically through a unit area under the condition of a unit concentration drop per unit time in the diffusion direction.

[0003] At present, the determination of gas diffusion coefficient mainly adopts the method of "controlling pressure at both ends separately" to measure gas diffusion coefficient. It is necessary to set two pressure sensors at both ends of the test core to measure the gas pressure at the end respectively, and adjust according to the indication of the pressure sensor. It is impossible to ensure that the accuracy of the two pressure sensors is completely consistent, and thus it is impossible to ensure that there is no pressure difference at both ends of the test core during the measurement of gas diffusion coefficient, so that the measurement process cannot eliminate the influence of pressure difference. In this regard, the prior art also provides a pressure control device and a gas diffusion coefficient measurement device thereof, the pressure control device includes a first container with a first opening, a second opening and a third opening, wherein the first opening is used to connect one end of the core holder; a second container with a fourth opening, a fifth opening and a sixth opening, wherein the fourth opening is used to connect the other end of the core holder; and also includes a liquid supply unit, a balance pipe, the two ends of the balance pipe are respectively connected to the first container and the second container, and the balance pipe includes a horizontal pipe section, and a sliding member that can be provided in the horizontal pipe section to seal and separate the inside thereof, and the sliding member can slide horizontally in the horizontal pipe section to balance the pressure on both sides of the sliding member, so as to ensure that the gas pressure at both ends of the test core is consistent during the measurement of gas diffusion coefficient.

[0004] Since uranium hexafluoride has a high triple point temperature and is a colorless or light yellow crystal at room temperature and pressure, it will generate corrosive hydrofluoric acid (HF) when it reacts with water vapor in the air. Therefore, the above-mentioned prior art is not suitable for measuring the gas diffusion coefficient of uranium hexafluoride. Summary of the invention

[0005] In order to overcome the defects of the prior art, the object of the present invention is to provide a device and method for measuring the gas diffusion coefficient of uranium hexafluoride. The device is used to realize the free diffusion process of gaseous uranium hexafluoride in the air. By sampling and analyzing this process, the gas diffusion coefficient of uranium hexafluoride can be calculated.

[0006] In order to achieve the above object, the present invention provides a device for measuring the diffusion coefficient of uranium hexafluoride gas, comprising:

[0007] A first constant pressure tube, with valves installed near both ends thereof, and a first opening is provided on the first constant pressure tube between the valves;

[0008] a diffusion tube, one end of which is connected to the first opening of the first constant pressure tube; a second opening is provided on the diffusion tube, and the second opening is used for connecting an external sampling device;

[0009] A second constant pressure tube, with valves installed near both ends thereof, and a third opening is provided on the second constant pressure tube between the valves, and the third opening is connected to the other end of the diffusion tube;

[0010] A plurality of flow meters are respectively arranged on the outer pipes of the first constant pressure tube and the second constant pressure tube close to the valve;

[0011] A plurality of pressure gauges are respectively arranged on the inner pipes of the first constant pressure tube and the second constant pressure tube close to the valve;

[0012] Electric heating equipment is arranged outside the first constant pressure tube, the diffusion tube and the second constant pressure tube.

[0013] Furthermore, the sampling device is connected to the second opening of the diffusion tube by a quick interface or a thread, and a valve is provided on the sampling device and an electromagnetic valve is used to control the opening and closing of the valve.

[0014] Furthermore, the diameter of the sampling device is smaller than or equal to the diameter of the diffusion tube.

[0015] Further, a first constant pressure valve is installed at one end of the first constant pressure tube, and a first regulating valve is installed at the other end of the first constant pressure tube;

[0016] A second constant pressure valve is installed at one end of the second constant pressure tube, and a second regulating valve is installed at the other end of the second constant pressure tube;

[0017] The first constant pressure valve, the first regulating valve, the second constant pressure valve and the second regulating valve are used to regulate the pressure inside the first constant pressure tube and the second constant pressure tube.

[0018] Furthermore, a fourth opening is provided on the second constant pressure tube located outside the second regulating valve, and the fourth opening is used for an external sampling device.

[0019] Furthermore, the number of the fourth openings is two, a valve is installed on the portion of the second constant pressure tube between the two fourth openings, and the sampling device is connected in parallel to the outside of the valve on the second constant pressure tube.

[0020] Furthermore, the sampling device externally connected to the fourth opening is connected in parallel to the second constant pressure tube using a hose; and the sampling device is provided with a valve whose opening and closing is controlled by a solenoid valve.

[0021] Furthermore, an electric heating device is provided outside the sampling device.

[0022] Furthermore, it includes a uranium hexafluoride container and a heating device;

[0023] The uranium hexafluoride container is connected to one end of the first constant pressure tube and is used to contain solid uranium hexafluoride;

[0024] The heating device is used to heat the uranium hexafluoride container to vaporize the uranium hexafluoride in the uranium hexafluoride container and pass it into the first constant pressure tube.

[0025] On the other hand, the present invention also provides a method for measuring the uranium hexafluoride gas diffusion coefficient, using the uranium hexafluoride gas diffusion coefficient measuring device as described above, the method comprising the following steps:

[0026] Continuously introducing uranium hexafluoride gas into the first constant pressure tube;

[0027] After the pressure gauge and the flow meter are stable, the constant pressure valves on the first constant pressure tube and the second constant pressure tube are adjusted according to the sizes of the pressure gauge and the flow meter, so that the two flow meters on each constant pressure tube display the same flow rate;

[0028] After collecting the sample gas through the sampling device, closing the valve on the sampling device;

[0029] The concentration and diffusion flux of the sample gas were measured, and the gas diffusion coefficient of uranium hexafluoride was calculated.

[0030] The uranium hexafluoride gas diffusion coefficient measuring device provided by the present invention has the following beneficial effects compared with the prior art:

[0031] By adjusting the pressure inside the device, gaseous uranium hexafluoride can freely diffuse from the first constant pressure tube through the diffusion tube to the second constant pressure tube, and then the gas diffusion coefficient of uranium hexafluoride can be calculated by sampling and analyzing this process. Electric heating equipment is provided on the outside of the first constant pressure tube, the diffusion tube and the second constant pressure tube to prevent condensation of uranium hexafluoride during the process, filling the gap in the uranium hexafluoride gas diffusion coefficient measurement device in the industry.

[0032] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 This is a schematic structural diagram of a device for measuring the diffusion coefficient of uranium hexafluoride gas according to an embodiment of the present invention;

[0035] Figure 2 This is a flow chart of a method for measuring the diffusion coefficient of uranium hexafluoride gas according to an embodiment of the present invention;

[0036] Figure 3 The figure is a schematic diagram of a process for measuring the diffusion coefficient of uranium hexafluoride gas according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0038] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0039] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0040] It should be noted that the concepts of “first”, “second”, etc. may be mentioned in the present invention only to distinguish different devices, components or parts, and are not used to limit the order or interdependence of the functions performed by these devices, components or parts.

[0041] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more". "Plurality" should be understood as two or more.

[0042] In an embodiment of the present invention, a device and method for measuring the diffusion coefficient of uranium hexafluoride gas are provided, the device comprising:

[0043] A first constant pressure tube, with valves installed near both ends thereof, and a first opening is provided on the first constant pressure tube between the valves;

[0044] a diffusion tube, one end of which is connected to the first opening of the first constant pressure tube; a second opening is provided on the diffusion tube, and the second opening is used for connecting an external sampling device;

[0045] A second constant pressure tube, with valves installed near both ends thereof, and a third opening is provided on the second constant pressure tube between the valves, and the third opening is connected to the other end of the diffusion tube;

[0046] A plurality of flow meters are respectively arranged on the outer pipes of the first constant pressure tube and the second constant pressure tube close to the valve;

[0047] A plurality of pressure gauges are respectively arranged on the inner pipes of the first constant pressure tube and the second constant pressure tube close to the valve;

[0048] Electric heating equipment is arranged outside the first constant pressure tube, the diffusion tube and the second constant pressure tube.

[0049] Example 1

[0050] The uranium hexafluoride gas diffusion coefficient measuring device of the embodiment of the present invention includes a diffusion device and a sampling device. The diffusion device is used to realize the free diffusion process of UF6 gas, and the sampling device is used to sample the process, and then calculate the UF6 gas diffusion coefficient according to the sampling data. Figure 1 The structure diagram of the device for measuring the diffusion coefficient of uranium hexafluoride gas according to an embodiment of the present invention is shown below. Figure 1 The specific implementation of this embodiment is described in detail.

[0051] The diffusion device of the embodiment of the present invention comprises a UF6 constant pressure tube 101, a diffusion tube 102 and an air constant pressure tube 103. The UF6 constant pressure tube 101 is used to pass UF6 gas, the air constant pressure tube 103 is used to pass dry air (dry and clean air without water vapor, liquid and solid impurities), and the two ends of the diffusion tube 102 are respectively connected to the UF6 constant pressure tube 101 and the air constant pressure tube 103, so that the UF6 gas can diffuse freely inside the diffusion tube 102.

[0052] A first constant pressure valve 104 is provided at one end (inlet end) of the UF6 constant pressure tube 101, and a first regulating valve 105 is provided at the other end of the UF6 constant pressure tube 101. Similarly, a second constant pressure valve 106 is provided at one end (inlet end) of the air constant pressure tube 103, and a second regulating valve 107 is provided at the other end of the air constant pressure tube 103. Flow meters 108 and pressure gauges 109 are installed on the pipelines on both sides of the first constant pressure valve 104, the first regulating valve 105, the second constant pressure valve 106, and the second regulating valve 107, wherein the flow meter 108 is arranged close to the outer pipeline of the valve, and the pressure gauge 109 is arranged close to the inner pipeline of the valve. Figure 1 As shown, "P" represents a pressure gauge and "F" represents a flow meter.

[0053] The sampling device of the embodiment of the present invention includes a sampling tube 110. The sampling tube 110 can be connected to the diffusion tube 102 to take samples at the reserved interface of the diffusion tube 102, and measure and obtain the uranium hexafluoride concentration at the interface point. By adjusting the constant pressure valve and the regulating valve on the UF constant pressure tube 101 and the air constant pressure tube 103, the pressure in the two constant pressure tubes can be changed, so that UF6 gas can be freely diffused from the UF6 constant pressure tube 101 in the diffusion tube 102 to the air constant pressure tube 103, realizing the free diffusion process of UF6 gas, and then by measuring and sampling the process, the diffusion coefficient of UF6 gas is calculated.

[0054] In the embodiment of the present invention, since the triple point temperature of UF6 is high and it is in a solid state at room temperature, in order to prevent UF6 from condensing during the measurement process, an electric heating device 111 is provided outside the UF6 constant pressure tube 101, the diffusion tube 102 and the air constant pressure tube 103. The electric heating device 111 can keep the pipeline temperature above the UF6 triple point temperature to prevent UF6 from condensing during the measurement experiment.

[0055] In some exemplary embodiments, a first opening is provided on the side wall of the UF6 constant pressure tube 101 between the two valves, and a third opening is provided on the side wall of the air constant pressure tube 103 between the two valves. One end of the diffusion tube 102 is connected to the first opening of the UF6 constant pressure tube 101, and the other end is connected to the third opening of the air constant pressure tube 103, so that the UF6 constant pressure tube 101, the diffusion tube 102, and the air constant pressure tube 103 are connected.

[0056] In some exemplary embodiments, a second opening is provided on the side wall of the diffusion tube 102 for externally connecting a sampling tube 110, and an electric heating device is provided outside the sampling tube 110 to prevent UF6 from condensing. The sampling tube 110 does not react with UF6 and its hydrolysis products and can withstand HF corrosion.

[0057] In the embodiment of the present invention, in order to maintain a stable free diffusion state in the diffusion tube 102, the sampling device on the diffusion tube 102 cannot adopt a vacuum sampling method, and the gas should be allowed to diffuse freely into the sampling tube.

[0058] In some exemplary embodiments, the sampling tube 110 is connected to the second opening of the diffusion tube 102 by using a quick interface or a thread, and a valve is provided on the sampling tube 110 and an electromagnetic valve is used to control the opening and closing of the valve.

[0059] In some exemplary embodiments, the diameter of the sampling tube 110 is no greater than the diameter of the diffusion tube 102 .

[0060] The sampling device of the embodiment of the present invention further includes a sampling bottle 112 for sampling the tail gas flowing out of the air constant pressure tube 103 to obtain the diffusion flux of uranium hexafluoride. Figure 1 As shown, a sampling bottle 112 (or sampling tube) is externally connected to the air constant pressure tube 103 located outside the second regulating valve 107 .

[0061] In some exemplary embodiments, a fourth opening is provided on the air constant pressure tube 103 (hereinafter referred to as the tail gas pipe of the air constant pressure tube 103) located outside the second regulating valve 107, and the fourth opening is used to connect the sampling bottle 112. The sampling bottle 112 is provided with a valve and the opening and closing of the valve is controlled by an electromagnetic valve.

[0062] In some exemplary embodiments, a valve 113 is provided on the tail gas pipe of the air constant pressure pipe 103, and openings are provided on the air constant pressure pipe 103 on both sides of the valve 113 for connecting the sampling bottle 112 in parallel, such as Figure 1 As shown, the effect of the sampling bottle 112 on the flow field of the diffusion device is reduced.

[0063] The uranium hexafluoride gas diffusion coefficient measuring device of the present invention is used to collect samples, measure the uranium hexafluoride gas diffusion coefficient, and provide basic parameters for the safety analysis of uranium hexafluoride leakage accidents. Since the triple point temperature of uranium hexafluoride is relatively high, about 64°C, and it is a white solid at room temperature, therefore, in the process of measuring the uranium hexafluoride gas diffusion coefficient, in order to prevent the uranium hexafluoride from condensing into a solid, it is necessary to use an electric heating device to heat the entire diffusion coefficient measuring device so that the temperature of the device is always higher than the triple point of uranium hexafluoride.

[0064] The diffusion coefficient measurement principle is as follows:

[0065] According to Fick's first law, the diffusion flux of UF6 gas through a unit cross-sectional area perpendicular to the diffusion direction per unit time is proportional to the concentration gradient at the cross section, and the expression is as follows:

[0066]

[0067] Where: J is the diffusion flux, unit is kg / (m 2 s); A represents the cross-sectional area of ​​the diffusion tube, in m 2 ; m is the diffusion material flow rate, unit is kg; t is the time, unit is s; D is the diffusion coefficient, unit is m 2 s; X is the diffusion length, in m; C is the volume concentration of the diffusing substance, in kg / m 3 ; Indicates gradient concentration; the “–” sign indicates that the diffusion direction is in the opposite direction of the concentration gradient, that is, the diffusion component diffuses from the high concentration area to the low concentration area.

[0068] The uranium hexafluoride gas diffusion coefficient measuring device of the present invention adjusts the pressure of the UF6 constant pressure tube 101 and the air constant pressure tube 103 to maintain the pressure and flow rate of the two constant pressure tubes constant, so that the diffusion process of the UF6 gas in the diffusion tube 102 is in a steady state, and the UF6 gas passes through the diffusion tube 102 with a constant diffusion flux. At this time, at any sampling point in the diffusion tube 102, the concentration gradient of the UF6 gas along the diffusion direction is the same value, and the diffusion process satisfies the following expression:

[0069]

[0070] Wherein: X1, X2 are the axial coordinates of the positions of the two sampling points on the diffusion tube 102, and the unit is m; C1, C2 are the volume concentrations of the diffusion substances at the two sampling points on the diffusion tube, and the unit is kg / m3.

[0071] In the embodiment of the present invention, in the diffusion tube 102, when the UF6 gas diffuses to the end of the diffusion tube 102 (the end connected to the air constant pressure tube 103), the UF6 gas will be taken away by the air flowing rapidly through the air constant pressure tube 103. Therefore, it can be considered that the UF6 gas at the end of the diffusion tube 102 is 0 kg / m 3 According to the distance from the sampling point to the end of the diffusion tube 102 and the volume concentration of UF6 gas at the sampling point, the UF6 gas diffusion coefficient can be calculated:

[0072]

[0073] Where: L is the distance from the sampling point to the end of the diffusion tube 102, in meters; C0 is the volume concentration of UF6 gas at the sampling point, in kg / m 3 .

[0074] In the embodiment of the present invention, the tail gas sampling bottle 112 is used to sample the tail gas flowing out of the air constant pressure tube 103 to obtain the diffusion flux of uranium hexafluoride. In order to reduce the influence on the flow field of the diffusion device, the sampling bottle 112 is connected in parallel to the tail gas pipe part of the air constant pressure tube 103 to measure the volume concentration of UF6 in the sample. The tail gas pipe of the air constant pressure tube 103 is equipped with a volume flow meter 108. According to the flow displayed by the flow meter 108 on the tail gas pipe, the diffusion flux of uranium hexafluoride can be calculated:

[0075]

[0076] Where: J is the diffusion flux, unit is kg / (m 2 s); A is the cross-sectional area of ​​the diffusion tube, in m 2 ; Q is the exhaust gas volume flow rate, unit is m 3 / s; C is the volume concentration of uranium hexafluoride, unit: kg / m 3 .

[0077] In some exemplary embodiments, the sampling bottle 112 is connected in parallel to the tail gas pipe of the air constant pressure pipe 103 by a hose, and the opening and closing of the valve on the sampling bottle 112 is controlled by a solenoid valve. In order to prevent uranium hexafluoride from condensing on the pipe wall, the outside of the sampling bottle 112 is equipped with an electric heating device, and it does not react with UF6 and its hydrolysis products and can withstand HF corrosion.

[0078] The uranium hexafluoride gas diffusion coefficient measuring device provided in this embodiment includes two parts, a diffusion device and a sampling device, and is a structure designed according to the characteristics of uranium hexafluoride, so that gaseous uranium hexafluoride can diffuse freely in the diffusion coefficient measuring device with electric heating, and then the parameters such as uranium hexafluoride concentration and flux are obtained through sampling, monitoring and other methods, and the uranium hexafluoride gas diffusion coefficient is derived and calculated. The prior art weaknesses in the field of uranium hexafluoride gas diffusion coefficient measurement are made up.

[0079] Example 2

[0080] In this embodiment, a method for measuring the uranium hexafluoride gas diffusion coefficient is provided, and the uranium hexafluoride gas diffusion coefficient measuring device of the above embodiment is used to measure the uranium hexafluoride gas diffusion coefficient. The method comprises:

[0081] Continuously introducing uranium hexafluoride gas into the first constant pressure tube;

[0082] After the pressure gauge and the flow meter are stable, the constant pressure valves on the first constant pressure tube and the second constant pressure tube are adjusted according to the sizes of the pressure gauge and the flow meter, so that the two flow meters on each constant pressure tube display the same flow rate;

[0083] After collecting the sample gas through the sampling device, closing the valve on the sampling device;

[0084] The concentration and diffusion flux of UF6 were measured, and the gas diffusion coefficient of UF6 was calculated.

[0085] Figure 2 This is a flow chart of a method for measuring the diffusion coefficient of uranium hexafluoride gas according to an embodiment of the present invention. Figure 3 The following is a schematic diagram of the measurement process of the uranium hexafluoride gas diffusion coefficient according to an embodiment of the present invention. Figure 2 and Figure 3 The specific implementation of this embodiment is described in detail.

[0086] First, in step 201, the feeding device is started to continuously introduce UF6 gas into the UF6 constant pressure tube 101.

[0087] In an embodiment of the present invention, the feeding device includes a uranium hexafluoride container and a heating device, wherein the uranium hexafluoride container is used to contain uranium hexafluoride powder, and the uranium hexafluoride container is heated by the heating device to convert the uranium hexafluoride powder into a gaseous state, and then the gaseous state is introduced into the UF6 constant pressure tube 101 through a feeding pipeline with an electric heating device.

[0088] In some exemplary embodiments, the feeding device further includes a control device for controlling the heating device to heat the uranium hexafluoride container, raising the temperature inside the uranium hexafluoride container to a preset temperature to vaporize the UF6 powder, and controlling the conduction of the feeding pipeline to provide gaseous UF6 to the UF6 constant pressure tube 101.

[0089] In some exemplary embodiments, before executing step 201, the method further includes:

[0090] (1) Check whether the equipment and valves are normal;

[0091] (2) Open all valves in the diffusion device and sampling device;

[0092] (3) Use dry air to purge the diffusion device pipeline;

[0093] (4) continuously introducing dry air into the air constant pressure tube 103;

[0094] (5) Close the valve on the exhaust gas pipeline connected in parallel with the exhaust gas sampling bottle 112;

[0095] (6) Turn on the electric heating device and set the temperature above 70°C as required, and maintain it for a period of time until the pipeline temperature reaches the set value;

[0096] (7) Start the tail gas recovery device;

[0097] After making full experimental preparations, start the feeding device and continuously introduce UF6 gas into the UF6 constant pressure tube 101.

[0098] In step 202, after the pressure gauge and flow meter are stabilized, the constant pressure valve is adjusted according to the size of the instrument so that the two flow meters of each constant pressure tube display the same flow rate. Figure 1 As shown, after UF6 gas is continuously introduced into the UF6 constant pressure tube 101 and waiting for a period of time, after each pressure meter and flow meter are stable, the first constant pressure valve 104 and the second constant pressure valve 106 are adjusted according to the size of the pressure meter and the flow meter, so that the two flow meters of the UF6 constant pressure tube 101 show the same flow rate, and the two flow meters on the air constant pressure tube 103 show the same flow rate.

[0099] In step 203, samples are collected through the sampling tube on the diffusion tube 102 and the sampling bottle on the air constant pressure tube 103. According to the size of the sampling tube on the diffusion tube 102 and the size of the exhaust gas sampling bottle on the air constant pressure tube 102, a sufficient amount of time is continued to wait after the pressure meter and the flow meter are stable so that the sampling tube and the sampling bottle can obtain enough samples.

[0100] At step 204 , the sampling tube valve on the diffusion tube 102 is closed.

[0101] In step 205, the valve on the exhaust gas pipeline of the air constant pressure tube 103 connected in parallel with the sampling bottle is opened, and the solenoid valve on the sampling bottle is closed.

[0102] In step 206, the introduction of UF6 gas into the UF6 constant pressure tube 101 is stopped.

[0103] Sample collection is completed through steps 201 to 206.

[0104] In the embodiment of the present invention, after the sample collection is completed, the device cleaning and result processing are also included, and the steps are as follows:

[0105] (1) Dry air at a temperature above 70° C. is introduced into the UF6 constant pressure tube 101, and the pipeline is continuously swept for a period of time, and the residual UF6 gas in the device is blown into the tail gas recovery device to condense and recover the UF6 in the tail gas;

[0106] (2) Turn off the exhaust gas recovery device;

[0107] (3) Close the valve of the diffusion device;

[0108] (4) Collect samples and detect UF6 concentration;

[0109] (5) Calculate the diffusion coefficient of UF6 gas in air.

[0110] The method for measuring the gas diffusion coefficient of uranium hexafluoride in the embodiment of the present invention adjusts the pressure inside the gas diffusion coefficient measuring device to achieve free diffusion of gaseous uranium hexafluoride from the UF6 constant pressure tube 101 through the diffusion tube 102 to the air constant pressure tube 103, and samples and analyzes this process to calculate the gas diffusion coefficient of uranium hexafluoride.

[0111] Those skilled in the art can understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for measuring the diffusion coefficient of uranium hexafluoride gas, characterized in that: include: A first constant pressure tube, with valves installed near both ends thereof, and a first opening is provided on the first constant pressure tube between the valves; a diffusion tube, one end of which is connected to the first opening of the first constant pressure tube; a second opening is provided on the diffusion tube, and the second opening is used for connecting an external sampling device; A second constant pressure tube, with valves installed near both ends thereof, and a third opening is provided on the second constant pressure tube between the valves, and the third opening is connected to the other end of the diffusion tube; A plurality of flow meters are respectively arranged on the outer pipes of the first constant pressure tube and the second constant pressure tube close to the valve; A plurality of pressure gauges are respectively arranged on the inner pipes of the first constant pressure tube and the second constant pressure tube close to the valve; Electric heating equipment is arranged outside the first constant pressure tube, the diffusion tube and the second constant pressure tube.

2. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 1, characterized in that: The sampling device is connected to the second opening of the diffusion tube by a quick interface or a thread, and a valve is provided on the sampling device and an electromagnetic valve is used to control the opening and closing of the valve.

3. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 1, characterized in that: The diameter of the sampling device is less than or equal to the diameter of the diffusion tube.

4. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 1, characterized in that: A first constant pressure valve is installed at one end of the first constant pressure tube, and a first regulating valve is installed at the other end of the first constant pressure tube; A second constant pressure valve is installed at one end of the second constant pressure tube, and a second regulating valve is installed at the other end of the second constant pressure tube; The first constant pressure valve, the first regulating valve, the second constant pressure valve and the second regulating valve are used to regulate the pressure inside the first constant pressure tube and the second constant pressure tube.

5. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 4, characterized in that: A fourth opening is provided on the second constant pressure tube located outside the second regulating valve, and the fourth opening is used for connecting an external sampling device.

6. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 5, characterized in that: The number of the fourth openings is two, a valve is installed on the portion of the second constant pressure tube between the two fourth openings, and the sampling device is connected in parallel to the outside of the valve on the second constant pressure tube.

7. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 5, characterized in that: The sampling device externally connected to the fourth opening is connected in parallel to the second constant pressure tube by a hose; the sampling device is provided with a valve whose opening and closing is controlled by a solenoid valve.

8. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 1 or 5, characterized in that: An electric heating device is arranged outside the sampling device.

9. The uranium hexafluoride gas diffusion coefficient measuring device according to claim 1, characterized in that: Also included are uranium hexafluoride containers and heating devices; The uranium hexafluoride container is connected to one end of the first constant pressure tube and is used to contain solid uranium hexafluoride; The heating device is used to heat the uranium hexafluoride container to vaporize the uranium hexafluoride in the uranium hexafluoride container and pass it into the first constant pressure tube.

10. A method for measuring the gas diffusion coefficient of uranium hexafluoride, using the uranium hexafluoride gas diffusion coefficient measuring device according to any one of claims 1 to 9, characterized in that: The method comprises: Continuously introducing uranium hexafluoride gas into the first constant pressure tube; After the pressure gauge and the flow meter are stable, the constant pressure valves on the first constant pressure tube and the second constant pressure tube are adjusted according to the sizes of the pressure gauge and the flow meter, so that the two flow meters on each constant pressure tube display the same flow rate; After collecting the sample gas through the sampling device, closing the valve on the sampling device; The concentration and diffusion flux of the sample gas were measured, and the gas diffusion coefficient of uranium hexafluoride was calculated.

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