Measuring device and measuring method for fluorination rate of uranium dioxide

Abstract

The embodiment of the invention discloses a measuring device and method for the fluorination rate of uranium dioxide. The measuring device comprises a pipeline assembly, a reaction container, a first gas source, a second gas source, a collecting container, a vacuum device, a switch assembly and a heating furnace. The pipeline assembly comprises a first pipeline unit, a second pipeline unit and a third pipeline unit. The reaction container comprises a container body and a container end cover, the container body is provided with a reaction cavity and an opening, and the reaction cavity is used for containing uranium dioxide. The first gas source is communicated with the reaction cavity and is used for supplying fluorine gas; the second gas source is communicated with the reaction cavity and is used for supplying inert gas. The collecting container is communicated with the reaction cavity and is used for collecting uranium hexafluoride. The vacuum device is arranged on the third pipeline unit and can be used for vacuumizing the collecting container and the reaction container. The switch assembly at least can be used for selectively connecting or disconnecting the first pipeline unit, the second pipeline unit and the third pipeline unit.

Description

Technical Field

[0001] The present application relates to the technical field of fluorination of uranium dioxide, and in particular to a device and method for measuring the fluorination rate of uranium dioxide. Background Art

[0002] The principle of fluorination volatilization technology is to use the volatility difference between uranium, plutonium and fluorides of fragmented elements to separate and recover uranium and plutonium. This technology has the advantages of radiation resistance, low criticality risk, less radioactive waste, high uranium and plutonium recovery rate, and high decontamination coefficient. It is suitable for processing spent fuel with high burnup and short cooling period, and has good application prospects. In the related technology, there is a problem of low reliability of the measurement device of fluorination rate of uranium dioxide. Summary of the invention

[0003] In view of this, the embodiments of the present application hope to provide a device and method for measuring the fluorination rate of uranium dioxide with high reliability.

[0004] To solve the above problems, the technical solution of the embodiment of the present application is implemented as follows:

[0005] The present application embodiment provides a device for measuring the fluorination rate of uranium dioxide, comprising:

[0006] A pipeline assembly, the pipeline assembly comprising a first pipeline unit, a second pipeline unit and a third pipeline unit;

[0007] A reaction container, the reaction container comprising a container body and a container end cover, the container body being provided with a reaction chamber and an opening, the opening being communicated with the reaction chamber, the container end cover being covered on the opening, the reaction chamber being used to contain uranium dioxide;

[0008] a first gas source, the first gas source being connected to the reaction chamber through the first pipeline unit, and the first gas source being used to supply fluorine gas;

[0009] a second gas source, the second gas source being connected to the reaction chamber through the second pipeline unit, and the second gas source being used for supplying an inert gas;

[0010] a collecting container, the collecting container being in communication with the reaction chamber through the third pipeline unit, and the collecting container being used to collect uranium hexafluoride;

[0011] A vacuum device, which is disposed in the third pipeline unit and can be used to evacuate the collection container and the reaction container;

[0012] a switch assembly, wherein the switch assembly can at least be used to selectively connect or close the first pipeline unit, the second pipeline unit, and the third pipeline unit;

[0013] A heating furnace, in which at least a portion of the container body is disposed.

[0014] In some embodiments, the measuring device further comprises a heat exchange device, wherein the heat exchange device comprises a heat exchange element, wherein the heat exchange element is arranged around the circumference of the collecting container, wherein a heat exchange medium is provided inside the heat exchange element, and wherein the heat exchange medium is used to perform heat exchange with the uranium hexafluoride gas flowing through the collecting container so that the uranium hexafluoride gas is condensed on the inner wall of the collecting container.

[0015] In some embodiments, the heat exchange device includes a condensation pipeline and a condensation circulation pump, the heat exchange element has an inlet and an outlet, both ends of the condensation pipeline are connected to the inlet and the outlet respectively, and the condensation circulation pump is arranged in the condensation pipeline.

[0016] In some embodiments, the measuring device also includes an exhaust gas treatment device, the pipeline assembly also includes a fourth pipeline unit, the fourth pipeline unit is connected in parallel to part of the third pipeline unit, the exhaust gas treatment device is arranged in the fourth pipeline unit, and the switch assembly can selectively connect or close the fourth pipeline unit.

[0017] In some embodiments, the reaction container includes a temperature measuring thermocouple, and at least a portion of the temperature measuring thermocouple is disposed in the reaction chamber to detect the temperature in the reaction chamber.

[0018] In some embodiments, the material of the reaction container includes monel alloy.

[0019] In some embodiments, the material of the pipeline assembly includes at least one of stainless steel and copper.

[0020] In some embodiments, the measuring device comprises a mass flow meter, and the first pipeline unit is provided with the mass flow meter.

[0021] In some embodiments, the measuring device includes a mass flow meter, and the second pipeline unit is provided with the mass flow meter.

[0022] In some embodiments, the tail gas treatment device includes an alkali absorption tank, and the alkali absorption tank is used to store alkaline substances.

[0023] In some embodiments, the tail gas treatment device includes an activated carbon absorption tank, in which activated carbon is arranged, and the activated carbon absorption tank is arranged between the alkali absorption tank and the vacuum device.

[0024] In some embodiments, the tail gas treatment device includes a buffer tank, and the buffer tank is disposed between the alkali absorption tank and the collection container.

[0025] In some embodiments, the measuring device comprises a pressure gauge;

[0026] The pipeline assembly includes a fifth pipeline unit, the first pipeline unit and the second pipeline unit are both connected to the reaction chamber through the fifth pipeline unit, and the fifth pipeline unit is provided with the pressure gauge.

[0027] In some embodiments, the pressure gauge is provided at the gas outlet of the collection container.

[0028] In some embodiments, the pressure gauge is made of a material resistant to fluorine corrosion.

[0029] The embodiment of the present application also provides a method for measuring the fluorination rate of uranium dioxide, which is applied to a device for measuring the fluorination rate of uranium dioxide. The device includes a reaction container, a first gas source, a vacuum device, and a heating furnace. The method includes:

[0030] Placing uranium dioxide to be reacted in the reaction chamber;

[0031] Controlling the vacuum device to evacuate the reaction chamber;

[0032] Opening the second gas source to supply inert gas to the reaction chamber, closing the second gas source, and controlling the vacuum device to evacuate the reaction chamber;

[0033] Turning on the heating furnace to heat the reaction chamber to a preset temperature;

[0034] Controlling the vacuum device to evacuate the reaction chamber;

[0035] Open the first gas source to supply fluorine gas to the reaction chamber until the reaction chamber is at normal pressure, and close the first gas source;

[0036] Recording the reaction time and the gas pressure in the reaction chamber until the reaction is completed;

[0037] Based on the reaction time and the gas pressure in the reaction chamber, the fluorination rate of the uranium dioxide is obtained.

[0038] In some embodiments, obtaining the fluorination rate of uranium dioxide based on the reaction time and the pressure change in the reaction chamber includes:

[0039] Taking the derivative of the P vs. t curve, we get

[0040] The fluorination rate of uranium dioxide is

[0041] Wherein, V is the volume of the reaction chamber, t is the reaction time, P is the gas pressure in the reaction chamber, R is a constant of 8.314 J / (mol·K), and temperature T is a preset temperature.

[0042] In some embodiments, the measuring device further comprises a heat exchange device, the heat exchange device comprises a heat exchange element, and the heat exchange element is disposed around the circumference of the collection container;

[0043] After the reaction is completed, the measuring method comprises:

[0044] The heat exchange device is turned on, and the heat exchange element exchanges heat with the uranium hexafluoride gas flowing through the collection container, so that the uranium hexafluoride gas is condensed on the inner wall of the collection container.

[0045] The measuring device of the fluorination rate of uranium dioxide of the embodiment of the present application, the uranium dioxide to be reacted is placed in the reaction chamber of the reaction vessel, and the air in the reaction chamber is discharged and filled with nitrogen through the cooperation of the second gas source and the vacuum device. Keep the reaction chamber sealed, then turn on the heating furnace, heat the reaction chamber to the reaction temperature, and control the vacuum device to evacuate the reaction chamber. Then turn on the first gas source, supply fluorine gas to the reaction chamber until it is normal pressure in the reaction chamber, and turn off the first gas source. In this way, the reaction between fluorine gas and uranium dioxide can be achieved, the reaction time and the air pressure in the reaction chamber are recorded until the reaction ends, and the fluorination rate of uranium dioxide can be obtained based on the reaction time and the air pressure in the reaction chamber. The measuring device is simple and reliable in structure, and can measure the fluorination rate of uranium dioxide under the condition of high concentration of fluorine gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of the structure of a device for measuring the fluorination rate of uranium dioxide in some embodiments of the present application;

[0047] Figure 2 This is a schematic flow chart of a method for measuring the fluorination rate of uranium dioxide according to some embodiments of the present application.

[0048] Description of Reference Numerals

[0049] 10. Pipeline assembly; 11. First pipeline unit; 12. Second pipeline unit; 13. Third pipeline unit; 14. Fourth pipeline unit; 15. Fifth pipeline unit; 20. Reaction vessel; 21. Container body; 22. Container end cover; 23. Reaction chamber; 24. Crucible; 30. First gas source; 40. Second gas source; 50. Collecting container; 60. Vacuum device; 70. Switch assembly; 80. Heating furnace; 90. Tail gas treatment device; 91. Alkali absorption tank; 92. Activated carbon absorption tank; 93. Buffer tank; 110. Temperature measuring thermocouple; 120. Mass flow meter; 130. Pressure gauge; 140. Heat exchange device; 141. Heat exchange element; 142. Condensation pipeline; 143. Condensation circulation pump. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and are therefore only used as examples, and the protection scope of the present application cannot be limited by this. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0051] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0054] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0055] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and may be direct contact or contact through an intermediate medium layer. It may be contact with essentially no interaction force between the two contacting parties, or it may be contact with interaction force between the two contacting parties.

[0056] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] An embodiment of the present application provides a device for measuring the fluorination rate of uranium dioxide.

[0058] See also Figure 1 The measuring device includes a pipeline assembly 10, a reaction container 20, a first gas source 30, a second gas source 40, a collection container 50, a vacuum device 60, a switch assembly 70 and a heating furnace 80. The pipeline assembly 10 includes a first pipeline unit 11, a second pipeline unit 12 and a third pipeline unit 13. The reaction container 20 includes a container body 21 and a container end cover 22. The container body 21 is provided with a reaction chamber 23 and an opening, the opening is connected to the reaction chamber 23, and the container end cover 22 is covered on the opening. The reaction chamber 23 is used to contain uranium dioxide. The first gas source 30 is connected to the reaction chamber 23 through the first pipeline unit 11, and the first gas source 30 is used to supply fluorine gas. The second gas source 40 is connected to the reaction chamber 23 through the second pipeline unit 12, and the second gas source 40 is used to supply inert gas. The collection container 50 is connected to the reaction chamber 23 through the third pipeline unit 13, and the collection container 50 is used to collect uranium hexafluoride. The vacuum device 60 is disposed in the third pipeline unit 13, and the vacuum device 60 can be used to evacuate the collection container 50 and the reaction container 20. The switch assembly 70 can at least be used to selectively connect or close the first pipeline unit 11, the second pipeline unit 12 and the third pipeline unit 13. At least part of the container body 21 is disposed in the heating furnace 80.

[0059] Here, the pipe assembly 10 is mainly used to connect various parts of the measuring device.

[0060] The reaction vessel 20 is a reaction device part of the measuring device, that is, the reaction vessel 20 mainly serves as a reaction device between uranium dioxide and fluorine gas.

[0061] Illustratively, the reaction vessel 20 includes a vessel body 21 and a vessel end cover 22 .

[0062] The container body 21 is provided with a reaction chamber 23 and an opening, and uranium dioxide can be accommodated in the reaction chamber 23 through the opening.

[0063] Here, the container body 21 is in a can shape, that is, the container body 21 is, for example, a reaction tank.

[0064] The container end cover 22 covers the container body 21 and is disposed at the opening and connected to the container body 21 .

[0065] Exemplarily, the container end cover 22 is sealed with the container body 21, that is, the container end cover 22 has a good airtight seal after being connected with the container body 21, which is beneficial to improve the reliability of the reaction between uranium dioxide and fluorine gas.

[0066] Exemplarily, the reaction vessel 20 includes a crucible 24, which is disposed in the container body 21 and is used to carry uranium dioxide.

[0067] Exemplarily, the first gas source 30 may include a fluorine gas cylinder, and the fluorine gas cylinder is used to store fluorine gas.

[0068] Exemplarily, the first gas source 30 may include an inert gas bottle, and the inert gas bottle is used to store an inert gas, and the inert gas includes but is not limited to nitrogen.

[0069] Illustratively, the uranium dioxide is in pellet form and / or powder form.

[0070] Here, the second gas source 40 is used to supply an inert gas, which is beneficial to exhausting the air in the reaction chamber 23, and can improve the measurement accuracy of the fluorination rate by filling the reaction chamber 23 with the inert gas during the temperature rise stage.

[0071] Here, the switch assembly 70 is used to selectively connect or close the first pipeline unit 11, the second pipeline unit 12 and the third pipeline unit 13 to achieve the connection and disconnection of the first pipeline unit 11, the second pipeline unit 12 and the third pipeline unit 13, thereby achieving the connection and disconnection between the first gas source 30, the second gas source 40 and the vacuum device 60 and the collection container 50.

[0072] Exemplarily, the switch assembly 70 includes but is not limited to a switch valve, a one-way valve, and the like.

[0073] At least a portion of the container body 21 is disposed in the heating furnace 80 , that is, the container body 21 can be heated by the heating furnace 80 .

[0074] The measuring device of the fluorination rate of uranium dioxide of the embodiment of the present application, the uranium dioxide to be reacted is placed in the reaction chamber 23 of the reaction vessel 20, and the air in the reaction chamber 23 is discharged and filled with nitrogen through the cooperation of the second gas source 40 and the vacuum device 60. Keep the reaction chamber 23 sealed, then turn on the heating furnace 80, heat the reaction chamber 23 to the reaction temperature, and control the vacuum device 60 to evacuate the reaction chamber 23. Then turn on the first gas source 30, supply fluorine gas to the reaction chamber 23 until the reaction chamber 23 is at normal pressure, and turn off the first gas source 30. In this way, the reaction between fluorine gas and uranium dioxide can be achieved, the reaction time and the air pressure in the reaction chamber 23 are recorded until the reaction ends, and the fluorination rate of uranium dioxide can be obtained based on the reaction time and the air pressure in the reaction chamber 23. The measuring device has a simple and reliable structure, and can measure the fluorination rate of uranium dioxide under the condition of high concentration of fluorine gas.

[0075] In some embodiments, see Figure 1 The measuring device further comprises a heat exchange device 140, which comprises a heat exchange element 141. The heat exchange element 141 is arranged around the collecting container 50. The heat exchange element 141 has a heat exchange medium inside. The heat exchange medium is used to exchange heat with the uranium hexafluoride gas flowing through the collecting container 50, so that the uranium hexafluoride gas condenses on the inner wall of the collecting container 50.

[0076] Exemplarily, the heat exchange element 141 is, for example, a condensation jacket, which is wrapped around the circumferential side wall of the collection container 50 and is used for exchanging heat with the uranium hexafluoride gas flowing through the collection container 50 .

[0077] Here, the specific type of heat exchange medium is not limited, and includes but is not limited to water.

[0078] In this embodiment, a heat exchange device 140 including a heat exchange element 141 is provided to allow the uranium hexafluoride gas flowing through the collection container 50 to undergo heat exchange, so that the uranium hexafluoride gas is condensed on the inner wall of the collection container 50, thereby achieving collection of the uranium hexafluoride.

[0079] In some embodiments, see Figure 1 The heat exchange device 140 includes a condensation pipeline 142 and a condensation circulation pump 143 . The heat exchange element 141 has an inlet and an outlet. Both ends of the condensation pipeline 142 are respectively connected to the inlet and the outlet. The condensation circulation pump 143 is arranged in the condensation pipeline 142 .

[0080] That is, the heat exchange element 141, the condensation pipeline 142 and the condensation circulation pump 143 form a heat exchange circulation loop, which is conducive to further improving the heat exchange efficiency, thereby improving the collection of uranium hexafluoride. In addition, it is also conducive to keeping the collection container 50 at a set temperature through the heat exchange device 140.

[0081] Exemplarily, the heat exchange device 140 may further include a medium container, and the medium container is used to store the heat exchange medium.

[0082] Here, the condensation circulation pump 143 is used to provide power to allow the heat exchange medium to circulate in the heat exchange circulation loop.

[0083] It should be noted that other gases generated by the reaction of uranium dioxide and fluorine gas can be directly discharged through the vacuum device 60, or can be treated by setting up a tail gas treatment device 90.

[0084] In some embodiments, see Figure 1 The measuring device also includes an exhaust gas treatment device 90, and the pipeline assembly 10 also includes a fourth pipeline unit 14, which is connected in parallel to part of the third pipeline unit 13. The exhaust gas treatment device 90 is arranged in the fourth pipeline unit 14, and the switch assembly 70 can selectively connect or close the fourth pipeline unit 14.

[0085] When evacuating, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be closed by controlling the switch, so as to evacuate the collection container 50 through the third pipeline unit 13. During the reaction, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be connected by controlling the switch, and the area where the third pipeline unit 13 and the fourth pipeline unit 14 are connected in parallel can be closed. In this way, other gases can be processed by the exhaust gas treatment device 90 and then discharged through the vacuum device 60. This helps to reduce the possibility of gas polluting the environment or causing harm to people.

[0086] In some embodiments, please refer to Figure 1 The tail gas treatment device 90 includes an alkali absorption tank 91, and the alkali absorption tank 91 is used to store alkaline substances.

[0087] It should be noted that the specific type of the alkaline substance is not limited herein. For example, the alkaline substance is, for example, soda lime solution.

[0088] In this embodiment, an alkali absorption tank 91 storing alkaline substances is provided, and unreacted fluorine gas will be absorbed by the alkaline substances after entering the alkali absorption tank 91, which is beneficial to reduce the corrosion of fluorine gas to subsequent equipment, and can also reduce the possibility of polluting the environment or causing damage to people.

[0089] In some embodiments, please refer to Figure 1 The tail gas treatment device 90 includes an activated carbon absorption tank 92 , in which activated carbon is arranged. The activated carbon absorption tank 92 is arranged between the alkali absorption tank 91 and the vacuum device 60 .

[0090] In this embodiment, an activated carbon absorption tank 92 storing activated carbon is provided, and other impurities or liquids entering the activated carbon absorption tank 92 will be absorbed by the activated carbon tank, which is beneficial to drying and purifying the gas, thereby reducing the possibility of polluting the environment or causing harm to people.

[0091] In some embodiments, please refer to Figure 1 The tail gas treatment device 90 includes a buffer tank 93 , and the buffer tank 93 is disposed between the alkali absorption tank 91 and the collection container 50 .

[0092] In this embodiment, a buffer tank 93 is provided and disposed between the alkali absorption tank 91 and the collection container 50. In the event of back suction, the buffer tank 93 can, to a certain extent, buffer the liquid in the alkali absorption tank 91, thereby effectively preventing the liquid from entering the collection container 50 and the reaction container 20, which is beneficial to further improve the reliability of the measuring device.

[0093] In some embodiments, please refer to Figure 1 The reaction container 20 includes a temperature measuring thermocouple 110 , at least a portion of which is disposed in the reaction chamber 23 for detecting the temperature in the reaction chamber 23 .

[0094] In this embodiment, a temperature measuring thermocouple 110 is provided to measure the actual temperature of the reaction tank, thereby facilitating improving the measurement accuracy of the fluorination rate of uranium dioxide.

[0095] In some embodiments, see Figure 1 The material of the reaction container 20 includes monel alloy.

[0096] Here, by setting the material of the reaction container 20 to include monel alloy, it is beneficial to improve the structural strength of the reaction container 20 while also improving the corrosion resistance to fluorine gas and the like, further improving the reliability of the reaction container 20.

[0097] In some embodiments, see Figure 1 The material of the pipeline assembly 10 includes at least one of stainless steel and copper.

[0098] Exemplarily, the material of the pipe assembly 10 includes, for example, 316 stainless steel.

[0099] In this embodiment, by setting the material of the pipeline assembly 10 to include at least one of stainless steel and copper, it is beneficial to improve the structural strength of the pipeline assembly 10 while also improving the corrosion resistance to fluorine gas and other corrosion, further improving the reliability of the pipeline assembly 10.

[0100] In some embodiments, please refer to Figure 1, the measuring device includes a pressure gauge 130.

[0101] Here, the pressure gauge 130 is used to detect the pressure. By detecting and controlling the pressure, it is helpful to improve the measurement accuracy of the fluorination rate.

[0102] Exemplarily, the pressure gauge 130 may be a pressure gauge.

[0103] Exemplarily, the pipeline assembly 10 includes a fifth pipeline unit 15 , the first pipeline unit 11 and the second pipeline unit 12 are both connected to the reaction chamber 23 through the fifth pipeline unit 15 , and the fifth pipeline unit 15 is provided with a pressure gauge 130 .

[0104] That is, the first pipeline unit 11 and the second pipeline unit 12 are connected in parallel and then communicated with the fifth pipeline unit 15 .

[0105] In this way, the fluorine gas enters the reaction chamber 23 after passing through the first pipeline unit 11 and the fifth pipeline unit 15 in sequence. The inert gas enters the reaction chamber 23 after passing through the second pipeline unit 12 and the fifth pipeline unit 15 in sequence.

[0106] The fifth pipeline unit 15 is provided with a pressure gauge 130 , and the fifth pipeline unit 15 is in communication with the reaction chamber 23 , so that the pressure gauge 130 can be used to measure the gas pressure in the reaction chamber 23 .

[0107] In some embodiments, see Figure 1 A pressure gauge 130 is provided at the gas outlet of the collecting container 50 .

[0108] In this way, by providing the pressure gauge 130 at the gas outlet of the collection container 50 , the gas pressure at the gas outlet of the collection container 50 can be measured.

[0109] In some embodiments, see Figure 1 The pressure gauge 130 is made of a material resistant to fluorine gas corrosion.

[0110] In this embodiment, by setting the material of the pressure gauge 130 to be a material resistant to fluorine gas corrosion, the corrosion resistance of the pressure gauge 130 can be improved, and the reliability of the pressure gauge 130 can be further improved.

[0111] In some embodiments, see Figure 1 The measuring device includes a mass flow meter 120 , and the first pipeline unit 11 is provided with the mass flow meter 120 .

[0112] In this way, the flow rate of fluorine gas can be controlled, further improving the measurement accuracy of the fluorination rate.

[0113] In some embodiments, see Figure 1The measuring device includes a mass flow meter 120 , and the second pipeline unit 12 is provided with the mass flow meter 120 .

[0114] In this way, the flow rate of the inert gas can be controlled, further improving the measurement accuracy of the fluorination rate.

[0115] The present application also provides a method for measuring the fluorination rate of uranium dioxide, which is applied to a device for measuring the fluorination rate of uranium dioxide. The device includes a reaction vessel 20, a first gas source 30, a vacuum device 60, and a heating furnace 80. Figure 2 , measurement methods include:

[0116] Step S210: placing uranium dioxide to be reacted in a reaction chamber;

[0117] Illustratively, the reaction vessel 20 includes a vessel body 21 and a vessel end cover 22 .

[0118] The container body 21 is provided with a reaction chamber 23 and an opening, and uranium dioxide can be accommodated in the reaction chamber 23 through the opening.

[0119] Here, the container body 21 is in a can shape, that is, the container body 21 is, for example, a reaction tank.

[0120] The container end cover 22 covers the container body 21 and is disposed at the opening and connected to the container body 21 .

[0121] Exemplarily, the container end cover 22 is sealed with the container body 21, that is, the container end cover 22 has a good airtight seal after being connected with the container body 21, which is beneficial to improve the reliability of the reaction between uranium dioxide and fluorine gas.

[0122] Exemplarily, the reaction vessel 20 includes a crucible 24, which is disposed in the container body 21 and is used to carry uranium dioxide.

[0123] Exemplarily, the crucible 24 is disposed at the bottom of the container body 21 .

[0124] Here, the container body 21 , the first gas source 30 , the second gas source 40 , the collection container 50 , the alkali absorption tank 91 , the activated carbon absorption tank 92 , the buffer tank 93 , and the vacuum device 60 are connected through the pipeline assembly 10 .

[0125] Step S220: controlling the vacuum device to evacuate the reaction chamber;

[0126] Step S230: turning on the second gas source to supply inert gas to the reaction chamber, turning off the second gas source, and controlling the vacuum device to evacuate the reaction chamber;

[0127] For example, see Figure 1The switch assembly 70 includes a first valve, which is arranged on the third pipeline unit 13 between the reaction container 20 and the collection container 50.

[0128] The switch assembly 70 includes a second valve, which is disposed on the fifth pipeline unit 15 .

[0129] The switch assembly 70 includes a third valve, a fourth valve, a fifth valve, and a sixth valve. The third valve is arranged on the third pipeline unit 13 between the fourth pipeline unit 14 and the collecting container 50. The fourth valve is arranged on the third pipeline unit 13 in parallel with the fourth pipeline unit 14. The fifth valve and the sixth valve are respectively arranged on the fourth pipeline unit 14 located upstream and downstream of the exhaust gas treatment device 90.

[0130] The vacuum device 60 is turned on, and the switch assembly 70 (i.e., the first valve, the third valve, and the fourth valve) between the vacuum device 60 and the reaction container 20 is opened in sequence to evacuate the reaction container 20. After the reaction container 20 is evacuated to a vacuum, the first valve between the reaction container 20 and the collection container 50 is closed. The second gas source 40 is turned on, the flow rate of the mass flow meter 120 on the second pipeline unit 12 is set, the second valve is opened, and the vacuum device 60 is controlled to evacuate the reaction chamber, and this is repeated three times.

[0131] Step S240: Turn on the heating furnace to heat the reaction chamber to a preset temperature;

[0132] The reaction container 20 is heated by the heating furnace 80 to heat the reaction chamber 23 to a preset temperature.

[0133] Here, the preset temperature is, for example, a reaction temperature.

[0134] Exemplarily, the measuring device includes a pipeline heating belt, and the pipeline heating belt can be turned on while the heating furnace 80 heats the reaction container 20.

[0135] Step S250: controlling the vacuum device to evacuate the reaction chamber;

[0136] After the reaction chamber 23 is heated to a preset temperature, the vacuum device 60 is controlled to evacuate the reaction chamber 23 .

[0137] Step S260: Turn on the first gas source, supply fluorine gas to the reaction chamber until the reaction chamber is at normal pressure, and then turn off the first gas source;

[0138] The first gas source 30 is turned on, and the fluorine gas mass flow meter 120 is set to control the flow of the fluorine gas. The second valve is opened, and the fluorine gas is filled into the reaction container 20 to normal pressure, and the second valve is closed.

[0139] Step S270: recording the reaction time and the gas pressure in the reaction chamber until the reaction is completed;

[0140] The time and pressure recorded while the reaction container 20 is filled with fluorine gas to normal pressure, the time is the time when the reaction starts, and the pressure is the pressure when the reaction starts.

[0141] The reading of the pressure gauge 130 on the fifth pipeline unit 15 is recorded at regular intervals until the pressure indicator does not change significantly for a period of time.

[0142] Step S280: obtaining the fluorination rate of uranium dioxide based on the reaction time and the gas pressure in the reaction chamber.

[0143] In some embodiments, see Figure 1 , based on the reaction time and the pressure change in the reaction chamber 23, the fluorination rate of uranium dioxide is obtained, including:

[0144] Taking the derivative of the P vs. t curve, we get

[0145] The fluorination rate of uranium dioxide is

[0146] Wherein, V is the volume of the reaction chamber 23, t is the reaction time, P is the gas pressure in the reaction chamber 23, R is a constant of 8.314 J / (mol·K), and temperature T is a preset temperature.

[0147] The reactions that occurred during the experiment were:

[0148] UO2(s)+3F2(g)→UF6(g)+O2(g)

[0149] Calculation of reaction rate: There are 3 F2 molecules before the reaction, and 1 UF6 molecule and 1 O2 molecule after the reaction. There is a difference of 1 gas molecule before and after the reaction, so a pressure difference will be generated. The reaction rate formula can be expressed as dn / dt, which is the change in the amount of substance per unit time. According to the curve of the pressure value P and time t obtained from the experimental record, dP / dt can be obtained by taking the derivative. According to PV=nRT, the reaction rate can be obtained The reaction rate is related to the concentration of the reactants. In this reaction condition, it is related to the F2 concentration in the reaction tank. Therefore, the obtained reaction rate is the reaction rate under the current reactant concentration.

[0150] In some embodiments, see Figure 1 The measuring device further includes a heat exchange device 140, the heat exchange device 140 includes a heat exchange element 141, and the heat exchange element 141 is disposed around the collecting container 50;

[0151] Until the reaction is complete, measurement methods include:

[0152] The heat exchange device 140 is turned on, and the heat exchange element 141 exchanges heat with the uranium hexafluoride gas flowing through the collection container 50 , so that the uranium hexafluoride gas condenses on the inner wall of the collection container 50 .

[0153] The heat exchange device 140 includes a heat exchange element 141, which is disposed around the collecting container 50. The heat exchange element 141 has a heat exchange medium inside. The heat exchange medium is used to exchange heat with the uranium hexafluoride gas flowing through the collecting container 50, so that the uranium hexafluoride gas condenses on the inner wall of the collecting container 50.

[0154] Exemplarily, the heat exchange element 141 is, for example, a condensation jacket, which is wrapped around the circumferential side wall of the collection container 50 and is used for exchanging heat with the uranium hexafluoride gas flowing through the collection container 50 .

[0155] Here, the specific type of heat exchange medium is not limited, and includes but is not limited to water.

[0156] In this embodiment, a heat exchange device 140 including a heat exchange element 141 is provided to allow the uranium hexafluoride gas flowing through the collection container 50 to undergo heat exchange, so that the uranium hexafluoride gas is condensed on the inner wall of the collection container 50, thereby achieving collection of the uranium hexafluoride.

[0157] In some embodiments, see Figure 1 The heat exchange device 140 includes a condensation pipeline 142 and a condensation circulation pump 143 . The heat exchange element 141 has an inlet and an outlet. Both ends of the condensation pipeline 142 are respectively connected to the inlet and the outlet. The condensation circulation pump 143 is arranged in the condensation pipeline 142 .

[0158] That is, the heat exchange element 141, the condensation pipeline 142 and the condensation circulation pump 143 form a heat exchange circulation loop, which is conducive to further improving the heat exchange efficiency, thereby improving the collection of uranium hexafluoride. In addition, it is also conducive to keeping the collection container 50 at a set temperature through the heat exchange device 140.

[0159] Exemplarily, the heat exchange device 140 may further include a medium container, and the medium container is used to store the heat exchange medium.

[0160] Here, the condensation circulation pump 143 is used to provide power to allow the heat exchange medium to circulate in the heat exchange circulation loop.

[0161] It should be noted that other gases generated by the reaction of uranium dioxide and fluorine gas can be directly discharged through the vacuum device 60, or can be treated by setting up a tail gas treatment device 90.

[0162] In some embodiments, see Figure 1The measuring device also includes an exhaust gas treatment device 90, and the pipeline assembly 10 also includes a fourth pipeline unit 14, which is connected in parallel to part of the third pipeline unit 13. The exhaust gas treatment device 90 is arranged in the fourth pipeline unit 14, and the switch assembly 70 can selectively connect or close the fourth pipeline unit 14.

[0163] When evacuating, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be closed by controlling the switch, so as to evacuate the collection container 50 through the third pipeline unit 13. During the reaction, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be connected by controlling the switch, and the area where the third pipeline unit 13 and the fourth pipeline unit 14 are connected in parallel can be closed. In this way, other gases can be processed by the exhaust gas treatment device 90 and then discharged through the vacuum device 60. This helps to reduce the possibility of gas polluting the environment or causing harm to people.

[0164] In some embodiments, see Figure 1 The tail gas treatment device 90 includes an alkali absorption tank 91, and the alkali absorption tank 91 is used to store alkaline substances.

[0165] It should be noted that the specific type of the alkaline substance is not limited herein. For example, the alkaline substance is, for example, soda lime solution.

[0166] In this embodiment, an alkali absorption tank 91 storing alkaline substances is provided, and unreacted fluorine gas will be absorbed by the alkaline substances after entering the alkali absorption tank 91, which is beneficial to reduce the corrosion of fluorine gas to subsequent equipment, and can also reduce the possibility of polluting the environment or causing damage to people.

[0167] In some embodiments, see Figure 1 The tail gas treatment device 90 includes an activated carbon absorption tank 92 , in which activated carbon is arranged. The activated carbon absorption tank 92 is arranged between the alkali absorption tank 91 and the vacuum device 60 .

[0168] In this embodiment, an activated carbon absorption tank 92 storing activated carbon is provided, and other impurities or liquids entering the activated carbon absorption tank 92 will be absorbed by the activated carbon tank, which is beneficial to drying and purifying the gas, thereby reducing the possibility of polluting the environment or causing harm to people.

[0169] In some embodiments, see Figure 1 The tail gas treatment device 90 includes a buffer tank 93 , and the buffer tank 93 is disposed between the alkali absorption tank 91 and the collection container 50 .

[0170] In this embodiment, a buffer tank 93 is provided and disposed between the alkali absorption tank 91 and the collection container 50. In the event of back suction, the buffer tank 93 can, to a certain extent, buffer the liquid in the alkali absorption tank 91, thereby effectively preventing the liquid from entering the collection container 50 and the reaction container 20, which is beneficial to further improve the reliability of the measuring device.

[0171] In this embodiment, the cooling program of the heating furnace 80 is set, the condensation circulation pump 143 is turned on at the same time, the condensation temperature is set, and the first valve is opened, and the uranium hexafluoride (UF6) product after the reaction will be condensed on the collection container 50. The vacuum device 60 is opened, and the sixth valve, the fifth valve, and the third valve are opened in sequence, and the fluorine gas and oxygen in the reaction container 20 and the vacuum device 60 will pass through the buffer tank 93, the alkali absorption tank 91, and the activated carbon absorption tank 92 in sequence, and the fluorine gas is absorbed by the soda lime in the alkali absorption tank 91, and the oxygen is discharged through the vacuum device 60.

[0172] After the reaction is finished, the fluorinated residue on the crucible 24 is taken out, and the product in the collection container 50 is taken out.

[0173] The following is a further description of the method for measuring the fluorination rate of uranium dioxide provided in the embodiments of the present application through two specific examples.

[0174] Embodiment 1:

[0175] The operation steps are as shown above, except that the condition parameters are different. The specific parameters are: weigh 20g of UO2 pellets and place them on the crucible 24, place them on the bottom of the container body 21, and seal the container body 21 with the container end cover 22. Then replace the air in the reaction container 20 with nitrogen, and then evacuate the reaction container 20. Then heat the heating furnace 80 to 550°C at a heating rate of 8°C / min. After keeping the temperature constant for 1 hour, evacuate the reaction container 20. Rapidly introduce fluorine gas to normal pressure at a flow rate of 10L / min, close the valve to maintain a closed environment in the reaction container 20, and record the time t and pressure value P at this time. Record the pressure value at this time every 5 minutes until there is no obvious change in pressure.

[0176] The volume V of the reaction vessel 20 is 19.52 L, R is a constant of 8.314 J / (mol·K), the temperature T is 823.15 K, the pressure P of the reaction vessel 20 changes from the initial 101 kPa to 80.156 kPa, and the fluorine gas in the reaction vessel 20 decreases from 101 kPa to 38.468 kPa. The relationship between the partial pressure of the reactant F2 and the concentration of the UO2 pellet reactant is summarized in the following table.

[0177] Reactant F2 partial pressure / kPa UO2 pellet reaction rate mmol / min

[0178] <![CDATA[Partial pressure of reactant F2 / kPa]]> <![CDATA[Reaction rate of UO2 pellets mmol / min <!-- 10 -->]]> 101 1.92 81.32 0.98 60.24 0.37 50.25 0.11

[0179] Embodiment 2:

[0180] The operation steps are as shown above, except that the condition parameters are different. The specific parameters are: weigh 20g of UO2 pellets and place them on the crucible 24, place them on the bottom of the reaction vessel 20, and seal the reaction vessel 20 with the lid of the reaction vessel 20. Then replace the air in the reaction vessel 20 with nitrogen, and then evacuate the reaction vessel 20. Then heat the heating furnace 80 to 600°C at a heating rate of 8°C / min. After keeping the temperature constant for 1 hour, evacuate the reaction vessel 20. Rapidly introduce fluorine gas to normal pressure at a flow rate of 10L / min, close the valve to maintain a closed environment in the reaction vessel 20, and record the time and pressure values ​​at this time. Record the pressure value at this time every 5 minutes until there is no obvious change in pressure. According to PV=nRT and the change in pressure, the reaction rate of the UO2 pellet can be calculated.

[0181] The volume V of the reaction vessel 20 is 19.52 L, R is a constant of 8.314 J / (mol·K), the temperature T is 873.15 K, the pressure P of the reaction vessel 20 changes from the initial 101 kPa to 73.613 kPa, and the fluorine gas in the reaction vessel 20 decreases from 101 kPa to 18.839 kPa. The relationship between the partial pressure of the reactant F2 and the concentration of the UO2 pellet reactant is shown in the following table.

[0182] Reactant F2 partial pressure / kPa UO2 pellet reaction rate mmol / min

[0183] Reactant F2 partial pressure / kPa UO2 pellet reaction rate mmol / min 101 3.49 79.63 1.96 60.28 0.99 39.78 0.40

[0184] According to the above experiments, the test method of the embodiment of the present application can accurately test the fluorination rate of uranium dioxide and the reaction rate under different reactant concentrations.

[0185] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application is described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A device for measuring the fluorination rate of uranium dioxide, characterized in that: include: A pipeline assembly, the pipeline assembly comprising a first pipeline unit, a second pipeline unit and a third pipeline unit; A reaction container, the reaction container comprising a container body and a container end cover, the container body being provided with a reaction chamber and an opening, the opening being communicated with the reaction chamber, the container end cover being covered on the opening, the reaction chamber being used to contain uranium dioxide; a first gas source, the first gas source being connected to the reaction chamber through the first pipeline unit, and the first gas source being used to supply fluorine gas; a second gas source, the second gas source being connected to the reaction chamber through the second pipeline unit, and the second gas source being used for supplying an inert gas; a collecting container, the collecting container being in communication with the reaction chamber through the third pipeline unit, and the collecting container being used to collect uranium hexafluoride; A vacuum device, which is disposed in the third pipeline unit and can be used to evacuate the collection container and the reaction container; a switch assembly, wherein the switch assembly can at least be used to selectively connect or close the first pipeline unit, the second pipeline unit, and the third pipeline unit; A heating furnace, in which at least a portion of the container body is disposed.

2. The measuring device according to claim 1, characterized in that The measuring device also includes a heat exchange device, which includes a heat exchange element. The heat exchange element is arranged around the collecting container. A heat exchange medium is provided inside the heat exchange element. The heat exchange medium is used to exchange heat with the uranium hexafluoride gas flowing through the collecting container, so that the uranium hexafluoride gas is condensed on the inner wall of the collecting container.

3. The measuring device according to claim 2, characterized in that The heat exchange device comprises a condensation pipeline and a condensation circulation pump. The heat exchange element has an inlet and an outlet. Both ends of the condensation pipeline are respectively connected to the inlet and the outlet. The condensation circulation pump is arranged on the condensation pipeline.

4. The measuring device according to claim 1, characterized in that The measuring device further includes an exhaust gas treatment device, the pipeline assembly further includes a fourth pipeline unit, the fourth pipeline unit is connected in parallel to part of the third pipeline unit, the exhaust gas treatment device is arranged in the fourth pipeline unit, and the switch assembly can selectively connect or close the fourth pipeline unit; and / or, The reaction container comprises a temperature measuring thermocouple, at least part of which is disposed in the reaction chamber for detecting the temperature in the reaction chamber; and / or, The material of the reaction container includes monel alloy; and / or, The material of the pipeline assembly includes at least one of stainless steel and copper; and / or, The measuring device comprises a mass flow meter, and the first pipeline unit is provided with the mass flow meter; and / or, The measuring device includes a mass flow meter, and the second pipeline unit is provided with the mass flow meter.

5. The measuring device according to claim 4, characterized in that The tail gas treatment device comprises an alkali absorption tank, and the alkali absorption tank is used to store alkaline substances.

6. The measuring device according to claim 5, characterized in that The tail gas treatment device comprises an activated carbon absorption tank, in which activated carbon is arranged, and the activated carbon absorption tank is arranged between the alkali absorption tank and the vacuum device; and / or, The tail gas treatment device comprises a buffer tank, and the buffer tank is arranged between the alkali absorption tank and the collection container.

7. The measuring device according to claim 1, characterized in that The measuring device comprises a pressure gauge; The pipeline assembly includes a fifth pipeline unit, the first pipeline unit and the second pipeline unit are both connected to the reaction chamber through the fifth pipeline unit, and the fifth pipeline unit is provided with the pressure gauge; and / or, The pressure gauge is provided at the gas outlet of the collecting container; and / or, The pressure gauge is made of a material resistant to fluorine gas corrosion.

8. A method for measuring the fluorination rate of uranium dioxide, applied to a device for measuring the fluorination rate of uranium dioxide, characterized in that: The measuring device comprises a reaction container, a first gas source, a second gas source, a vacuum device and a heating furnace, and the measuring method comprises: Placing uranium dioxide to be reacted in the reaction chamber; Controlling the vacuum device to evacuate the reaction chamber; Opening the second gas source to supply inert gas to the reaction chamber, closing the second gas source, and controlling the vacuum device to evacuate the reaction chamber; Turning on the heating furnace to heat the reaction chamber to a preset temperature; Controlling the vacuum device to evacuate the reaction chamber; Open the first gas source to supply fluorine gas to the reaction chamber until the reaction chamber is at normal pressure, and close the first gas source; Recording the reaction time and the gas pressure in the reaction chamber until the reaction is completed; Based on the reaction time and the gas pressure in the reaction chamber, the fluorination rate of the uranium dioxide is obtained.

9. The measuring method according to claim 8, characterized in that: The method of obtaining the fluorination rate of uranium dioxide based on the reaction time and the pressure change in the reaction chamber comprises: Taking the derivative of the P vs. t curve, we get The fluorination rate of uranium dioxide is Wherein, V is the volume of the reaction chamber, t is the reaction time, P is the gas pressure in the reaction chamber, R is a constant of 8.314 J / (mol·K), and temperature T is a preset temperature.

10. The measuring method according to claim 8, characterized in that: The measuring device further comprises a heat exchange device, wherein the heat exchange device comprises a heat exchange element, and the heat exchange element is arranged around the peripheral side of the collecting container; After the reaction is completed, the measuring method comprises: The heat exchange device is turned on, and the heat exchange element exchanges heat with the uranium hexafluoride gas flowing through the collection container, so that the uranium hexafluoride gas is condensed on the inner wall of the collection container.

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