Device and method for measuring the fluorination rate of uranium dioxide

Abstract

The embodiment of the present application discloses a kind of measuring device and measuring method of fluorination rate of uranium dioxide, measuring device includes pipeline assembly, reaction container, first gas source, second gas source, collection container, vacuum device, switch assembly and heating furnace.Pipeline assembly includes first pipeline unit, second pipeline unit and third pipeline unit.Reaction container includes container body and container end cover, container body is provided with reaction cavity and opening, reaction cavity is used to accommodate uranium dioxide.First gas source is communicated with reaction cavity, and first gas source is used to supply fluorine gas.Second gas source is communicated with reaction cavity, and second gas source is used to supply inert gas.Collection container is communicated with reaction cavity, and collection container is used to collect uranium hexafluoride.Vacuum device is arranged in third pipeline unit, and vacuum device can be used to vacuumize collection container and reaction container.Switch assembly can be used at least selectively to open or close first pipeline unit, second pipeline unit and third pipeline unit.

Description

TECHNICAL FIELD

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

[0002] The principle of the fluorination volatilization technology is to separate and recover uranium and plutonium by using the difference in volatility of uranium, plutonium and fluorinated elements. This technology has the advantages of radiation resistance, low critical risk, less radioactive waste, high uranium and plutonium recovery rate, and high decontamination factor, and is suitable for treating spent fuel with high burnup and short cooling period, and has good application prospect. In related technologies, there is a problem of low reliability of the device for measuring the fluorination rate of uranium dioxide. SUMMARY

[0003] Therefore, the embodiments of the present application aim 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 scheme of the embodiments of the present application is as follows:

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

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

[0007] A reaction container, comprising a container body and a container end cover, the container body is provided with a reaction cavity and an opening, the opening is in communication with the reaction cavity, the container end cover is arranged on the opening, and the reaction cavity is used for containing uranium dioxide;

[0008] A first gas source, in communication with the reaction cavity through the first pipeline unit, and used for supplying fluorine gas;

[0009] A second gas source, in communication with the reaction cavity through the second pipeline unit, and used for supplying inert gas;

[0010] A collection container, in communication with the reaction cavity through the third pipeline unit, and used for collecting uranium hexafluoride;

[0011] A vacuum device, arranged on the third pipeline unit, and capable of being used for vacuumizing the collection container and the reaction container;

[0012] A switch assembly, capable of selectively connecting or closing the first pipeline unit, the second pipeline unit and the third pipeline unit;

[0013] a heating furnace, at least a part of the container body being arranged in the heating furnace.

[0014] In some embodiments, the measuring device further comprises a heat exchange device, the heat exchange device comprising a heat exchange member, the heat exchange member being arranged around the collecting container, the heat exchange member having a heat exchange medium inside, the heat exchange medium being used to exchange heat with the uranium hexafluoride gas flowing through the collecting container, so that the uranium hexafluoride gas sublimes on the inner wall of the collecting container.

[0015] In some embodiments, the heat exchange device comprises a condensing pipeline and a condensing circulating pump, the heat exchange member has an inlet and an outlet, two ends of the condensing pipeline are in communication with the inlet and the outlet respectively, and the condensing circulating pump is arranged in the condensing pipeline.

[0016] In some embodiments, the measuring device further comprises a tail gas treatment device, the pipeline assembly further comprises a fourth pipeline unit, the fourth pipeline unit is connected in parallel on part of the third pipeline units, the tail gas treatment device is arranged in the fourth pipeline unit, and the switch assembly can selectively communicate or close the fourth pipeline unit.

[0017] In some embodiments, the reaction container comprises a temperature measuring thermocouple, at least a part of the temperature measuring thermocouple is arranged in the reaction cavity, and the temperature measuring thermocouple is used to detect the temperature in the reaction cavity.

[0018] In some embodiments, the material of the reaction container comprises Monel alloy.

[0019] In some embodiments, the material of the pipeline assembly comprises at least one of stainless steel and red 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 comprises 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 comprises an alkali absorption tank, and the alkali absorption tank is used to store alkaline substances.

[0023] In some embodiments, the tail gas treatment device comprises an activated carbon absorption tank, the activated carbon absorption tank is provided with activated carbon, 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 comprises a buffer tank, and the buffer tank is arranged between the alkali absorption tank and the collecting container.

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

[0026] The pipeline assembly comprises a fifth pipeline unit, the first pipeline unit and the second pipeline unit are communicated with the reaction cavity through the fifth pipeline unit, and the fifth pipeline unit is provided with the pressure gauge.

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

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

[0029] The embodiments of the present application further provide a method for measuring fluorination rate of uranium dioxide, which is applied to a measuring device for measuring fluorination rate of uranium dioxide, and the measuring device comprises a reaction container, a first gas source, a vacuum device and a heating furnace, and the measuring method comprises the following steps:

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

[0031] Controlling the vacuum device to vacuumize the reaction cavity;

[0032] Turning on the second gas source to supply inert gas to the reaction cavity, turning off the second gas source, and controlling the vacuum device to vacuumize the reaction cavity;

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

[0034] Controlling the vacuum device to vacuumize the reaction cavity;

[0035] Turning on the first gas source to supply fluorine gas to the reaction cavity to reach normal pressure in the reaction cavity, and turning off the first gas source;

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

[0037] Obtaining the fluorination rate of the uranium dioxide based on the reaction time and the gas pressure in the reaction cavity.

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

[0039] Deriving the curve of P and t to obtain

[0040] The fluorination rate of the uranium dioxide is

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

[0042] In some embodiments, the measuring device further comprises a heat exchange device, which comprises a heat exchange element surrounding the collecting container.

[0043] After the reaction ends, 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 collecting container, so that the uranium hexafluoride gas sublimes on the inner wall of the collecting container.

[0045] The measuring device for the fluorination rate of uranium dioxide according to the embodiments of the present application places the uranium dioxide to be reacted in the reaction cavity of the reaction container, discharges the air in the reaction cavity and fills it with nitrogen gas through the cooperation of the second gas source and the vacuum device. The reaction cavity is kept in a sealed state, and then the heating furnace is turned on to heat the reaction cavity to the reaction temperature, and the vacuum device is controlled to vacuumize the reaction cavity. Then the first gas source is turned on to supply fluorine gas to the reaction cavity until the air pressure in the reaction cavity is normal, and the first gas source is turned off. In this way, the reaction between fluorine gas and uranium dioxide can be realized, the reaction time and the air pressure in the reaction cavity 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 cavity. The measuring device is simple and reliable in structure, and can measure the fluorination rate of uranium dioxide under the condition of high-concentration fluorine gas. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The structure diagram of the measuring device for the fluorination rate of uranium dioxide according to some embodiments of the present application;

[0047] Figure 2 The flowchart of the measuring method for the fluorination rate of uranium dioxide according to some embodiments of the present application.

[0048] REFERENCE SIGNS

[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, vessel body; 22, vessel end cap; 23, reaction cavity; 24, crucible; 30, first gas source; 40, second gas source; 50, collection vessel; 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, condensing pipeline; 143, condensing circulating pump. DETAILED DESCRIPTION

[0050] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. The following embodiments are only used to make the technical solutions of the present application clearer, and therefore only serve as examples, but cannot be used to limit the protection scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] In the description of the embodiments of the present application, the technical terms “first”, “second”, “third” and the like 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 “a plurality of” is two or more, unless otherwise explicitly and specifically limited.

[0052] In this document, the phrase “embodiment” means that a specific feature, structure or property described in connection with an embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. A person of ordinary skill in the art explicitly and implicitly understands that the embodiments described herein can 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 the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character “ / ” in this document generally represents an “or” relationship between the front and rear associated objects.

[0054] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be interpreted broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the internal communication of two elements or the interaction relationship between two elements. For those skilled 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 specifically defined and limited otherwise, the technical term "contacting" should be interpreted broadly, which can be direct contact or contact through an intermediate medium layer, which can be contact between two contacting objects without interaction force, or contact between two contacting objects with interaction force.

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

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

[0058] Please refer to 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 cavity 23 and an opening, the opening is in communication with the reaction cavity 23, the container end cover 22 is covered on the opening, and the reaction cavity 23 is used for accommodating uranium dioxide. The first gas source 30 is in communication with the reaction cavity 23 through the first pipeline unit 11, and the first gas source 30 is used for supplying fluorine gas. The second gas source 40 is in communication with the reaction cavity 23 through the second pipeline unit 12, and the second gas source 40 is used for supplying inert gas. The collection container 50 is in communication with the reaction cavity 23 through the third pipeline unit 13, and the collection container 50 is used for collecting uranium hexafluoride. The vacuum device 60 is arranged in the third pipeline unit 13, and the vacuum device 60 can be used for vacuumizing the collection container 50 and the reaction container 20. The switch assembly 70 can be used at least for selectively opening or closing 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 arranged in the heating furnace 80.

[0059] Here, the pipeline assembly 10 is mainly used for connecting each part of the measuring device.

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

[0061] Exemplarily, the reaction container 20 comprises a container body 21 and a container end cover 22.

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

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

[0064] The container end cover 22 covers the opening of the container body 21 and is connected with the container body 21.

[0065] Exemplarily, the container end cover 22 is in sealed cooperation with the container body 21, that is, after the container end cover 22 is connected with the container body 21, the container end cover 22 has good air tightness, so as to be conducive to improving the reaction reliability between the uranium dioxide and the fluorine gas.

[0066] Exemplarily, the reaction container 20 comprises a crucible 24, which is arranged in the container body 21 and is used for carrying the uranium dioxide.

[0067] Exemplarily, the first gas source 30 can comprise a fluorine gas bottle, which is used for storing the fluorine gas.

[0068] Exemplarily, the first gas source 30 can comprise an inert gas bottle, which is used for storing an inert gas, including but not limited to nitrogen.

[0069] Exemplarily, the uranium dioxide is in the shape of a pellet and / or powder.

[0070] Here, the second gas source 40 is used for supplying the inert gas, which is conducive to discharging the air in the reaction cavity 23, and can improve the accuracy of the measurement of the fluorination rate by filling the inert gas in the reaction cavity 23 in the heating stage.

[0071] Here, the switch assembly 70 is used for selectively connecting or closing the first pipeline unit 11, the second pipeline unit 12 and the third pipeline unit 13, so as to realize the on-off of the first pipeline unit 11, the second pipeline unit 12 and the third pipeline unit 13, thereby realizing 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 comprises but is not limited to a switch valve, a one-way valve and the like.

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

[0074] The measuring device for the fluorination rate of the uranium dioxide in the embodiment of the application places the uranium dioxide to be reacted in the reaction cavity 23 of the reaction container 20, discharges the air in the reaction cavity 23 and fills the reaction cavity 23 with nitrogen by cooperation of the second gas source 40 and the vacuum device 60. The reaction cavity 23 is kept in a sealed state, then the heating furnace 80 is turned on to heat the reaction cavity 23 to a reaction temperature, and the vacuum device 60 is controlled to vacuumize the reaction cavity 23. Then the first gas source 30 is turned on to supply fluorine gas to the reaction cavity 23 to make the pressure in the reaction cavity 23 normal pressure, and the first gas source 30 is turned off. In this way, the reaction between the fluorine gas and the uranium dioxide can be realized, the reaction time and the gas pressure in the reaction cavity 23 are recorded until the reaction ends, and the fluorination rate of the uranium dioxide can be obtained based on the reaction time and the gas pressure in the reaction cavity 23. The measuring device is simple and reliable in structure and can realize the measurement of the fluorination rate of the uranium dioxide under the condition of high-concentration fluorine gas.

[0075] In some embodiments, referring to Figure 1 , the measuring device further comprises a heat exchange device 140, the heat exchange device 140 comprises a heat exchange member 141, the heat exchange member 141 is arranged around the periphery of the collection container 50, and the heat exchange member 141 has a heat exchange medium in the inside thereof, which is used to exchange heat with the uranium hexafluoride gas flowing through the collection container 50 so as to make the uranium hexafluoride gas condense on the inner wall of the collection container 50.

[0076] For example, the heat exchange member 141 is a condensing jacket which is wrapped around the circumferential side wall of the collection container 50 and is used to exchange heat with the uranium hexafluoride gas flowing through the collection container 50.

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

[0078] In the embodiment, the heat exchange device 140 comprising the heat exchange member 141 is arranged, the uranium hexafluoride gas flowing through the collection container 50 exchanges heat so as to make the uranium hexafluoride gas condense on the inner wall of the collection container 50, thereby realizing the collection of the uranium hexafluoride.

[0079] In some embodiments, referring to Figure 1 , the heat exchange device 140 comprises a condensing pipeline 142 and a condensing circulating pump 143, the heat exchange member 141 has an inlet and an outlet, the two ends of the condensing pipeline 142 are in communication with the inlet and the outlet respectively, and the condensing circulating pump 143 is arranged in the condensing pipeline 142.

[0080] That is to say, the heat exchange member 141, the condensing pipeline 142 and the condensing circulating pump 143 constitute a heat exchange circulating loop, and thus it is beneficial to further improve the heat exchange efficiency, thereby improving the collection of the uranium hexafluoride. In addition, it is also beneficial to keep the collection container 50 at a constant temperature through the heat exchange device 140.

[0081] Exemplarily, the heat exchange device 140 can further include a medium container for storing the heat exchange medium.

[0082] Here, the condensation circulating pump 143 is configured to provide power for the heat exchange medium to circulate in the heat exchange circulating loop.

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

[0084] In some embodiments, referring to Figure 1 , the measuring device further includes a tail gas treatment device 90, and the pipeline assembly 10 further includes a fourth pipeline unit 14, the fourth pipeline unit 14 is connected in parallel with the partial third pipeline unit 13, the tail 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] During the vacuumizing, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be closed through the control switch, so that the collection container 50 is vacuumized through the third pipeline unit 13, and during the reaction, the connection between the fourth pipeline unit 14 and the third pipeline unit 13 can be connected through the control switch, and the region where the third pipeline unit 13 and the fourth pipeline unit 14 are connected in parallel is closed, so that the other gas is treated through the tail gas treatment device 90 and then discharged through the vacuum device 60, which is conducive to reducing the possibility of polluting the environment or causing damage to people.

[0086] In some embodiments, referring to Figure 1 , the tail gas treatment device 90 includes an alkali absorption tank 91 for storing an alkaline substance.

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

[0088] In this embodiment, by arranging the alkali absorption tank 91 storing the alkaline substance, the fluorine gas which is not reacted enters the alkali absorption tank 91 and is absorbed by the alkaline substance, which is conducive to reducing the corrosion of the fluorine gas to the subsequent equipment, and can also reduce the possibility of polluting the environment or causing damage to people.

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

[0090] In this embodiment, the activated carbon absorption tank 92 is provided to store activated carbon. When other impurities or liquid enters the activated carbon absorption tank 92, the activated carbon tank can absorb the impurities or liquid, which is beneficial to dry and purify the gas, thereby reducing the possibility of polluting the environment or causing damage to people.

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

[0092] In this embodiment, the buffer tank 93 is arranged between the alkali absorption tank 91 and the collection container 50. In the case of reverse suction, the buffer tank 93 can store the liquid in the alkali absorption tank 91 to some extent, 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 part of which is arranged in the reaction cavity 23 to detect the temperature in the reaction cavity 23.

[0094] In this embodiment, the temperature measuring thermocouple 110 is arranged to measure the actual temperature of the reaction tank, which is beneficial to improve the measurement accuracy of the fluorination rate of uranium dioxide.

[0095] In some embodiments, please refer to Figure 1 The material of the reaction container 20 includes Monel alloy.

[0096] Here, the material of the reaction container 20 is set to include Monel alloy, which is beneficial to improve the structural strength of the reaction container 20, and also improves the corrosion resistance to fluorine gas and other corrosion, further improving the reliability of the reaction container 20.

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

[0098] For example, the material of the pipeline assembly 10 includes 316 stainless steel.

[0099] In this embodiment, the material of the pipeline assembly 10 is set to include at least one of stainless steel and red copper, which is beneficial to improve the structural strength of the pipeline assembly 10, and also improves 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 1The measuring device includes a pressure gauge 130.

[0101] Here, the pressure gauge 130 is used to detect pressure, and through detection and control of the pressure, the measurement accuracy of the fluorination rate is improved.

[0102] Exemplarily, the pressure gauge 130 can 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 communicated with the reaction cavity 23 through the fifth pipeline unit 15, and the fifth pipeline unit 15 is provided with the pressure gauge 130.

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

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

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

[0107] In some embodiments, referring to Figure 1 The gas outlet of the collection container 50 is provided with the pressure gauge 130.

[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, referring to Figure 1 The pressure gauge 130 is made of a fluorine-resistant material.

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

[0111] In some embodiments, referring to 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 of fluorine gas can be controlled, and the measurement accuracy of the fluorination rate is further improved.

[0113] In some embodiments, referring to 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 of the inert gas can be controlled, and the measurement accuracy of the fluorination rate is further improved.

[0115] The application further provides a method for measuring a fluorination rate of uranium dioxide, which is applied to a device for measuring the fluorination rate of uranium dioxide, and the measuring device includes a reaction container 20, a first gas source 30, a vacuum device 60, and a heating furnace 80. Figure 2 The measuring method includes the following steps.

[0116] In step S210, the uranium dioxide to be reacted is placed in the reaction cavity.

[0117] The reaction container 20 includes a container body 21 and a container end cover 22.

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

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

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

[0121] The container end cover 22 is in sealed fit with the container body 21, that is, the container end cover 22 has good air tightness after being connected to the container body 21, so as to improve the reaction reliability between the uranium dioxide and the fluorine gas.

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

[0123] The crucible 24 is arranged 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] In step S220, the vacuum device is controlled to vacuumize the reaction cavity.

[0126] In step S230, the second gas source is opened to supply the inert gas to the reaction cavity, the second gas source is closed, and the vacuum device is controlled to vacuumize the reaction cavity.

[0127] For example, the second gas source is opened to supply the inert gas to the reaction cavity, the second gas source is closed, and the vacuum device is controlled to vacuumize the reaction cavity. Figure 1The switching assembly 70 includes a first valve provided on the third pipeline unit 13 between the reaction vessel 20 and the collection vessel 50.

[0128] The switching assembly 70 includes a second valve provided on the fifth pipeline unit 15.

[0129] The switching assembly 70 includes a third valve provided on the third pipeline unit 13 between the fourth pipeline unit 14 and the collection vessel 50, a fourth valve provided on the third pipeline unit 13 in parallel with the fourth pipeline unit 14, and a fifth valve and a sixth valve provided on the fourth pipeline unit 14 upstream and downstream of the exhaust gas treatment device 90, respectively.

[0130] The vacuum device 60 is turned on, and then the switching assembly 70 (i.e. the first valve, the third valve and the fourth valve) between the vacuum device 60 and the reaction vessel 20 is turned on in sequence to vacuumize the reaction vessel 20. After the reaction vessel 20 is vacuumized, the first valve between the reaction vessel 20 and the collection vessel 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 vacuumize the reaction chamber. The above process is repeated three times.

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

[0132] The reaction vessel 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 tape, which can be turned on while the heating furnace 80 heats the reaction vessel 20.

[0135] Step S250: Control the vacuum device to vacuumize the reaction chamber.

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

[0137] Step S260: Turn on the first gas source to supply fluorine gas to the reaction chamber to a 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 rate of the fluorine gas. The second valve is opened to fill the reaction vessel 20 with fluorine gas to a normal pressure, and then the second valve is closed.

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

[0140] The time recorded while fluorine gas is filled into the reaction container 20 to the normal pressure 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 every certain time until the pressure gauge reading does not change significantly within a period of time.

[0142] Step S280: Based on the reaction time and the gas pressure in the reaction cavity, the fluorination rate of uranium dioxide is obtained.

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

[0144] The derivative of the curve of P and t is obtained

[0145] The fluorination rate of uranium dioxide is

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

[0147] The reaction occurring during the experiment is:

[0148] UO2(s)+3F2(g)→UF6(g)+O2(g)

[0149] Calculation of reaction rate: Before the reaction, there are 3 F2 molecules, and after the reaction, there is 1 UF6 molecule and 1 O2 molecule. There is a difference of 1 molecule of gas 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 of the amount of substance per unit time. According to the derivative of the curve of the pressure value P and the time t obtained by the experiment, dP / dt can be obtained, and according to PV=nRT, the reaction rate The reaction rate is related to the concentration of the reactant, and in this reaction condition, it is related to the F2 concentration in the reaction tank, so the obtained reaction rate is the reaction rate under the current concentration of the reactant.

[0150] In some embodiments, referring to Figure 1 , the measuring device further comprises a heat exchange device 140, and the heat exchange device 140 comprises a heat exchange piece 141, and the heat exchange piece 141 is arranged around the periphery of the collection container 50;

[0151] Until the reaction is completed, the measuring method comprises:

[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 sublimes on the inner wall of the collection container 50.

[0153] The heat exchange device 140 includes the heat exchange element 141, which is arranged around the collection container 50, and the heat exchange element 141 has a heat exchange medium inside, which exchanges heat with the uranium hexafluoride gas flowing through the collection container 50, so that the uranium hexafluoride gas sublimes on the inner wall of the collection container 50.

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

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

[0156] In this embodiment, by arranging the heat exchange device 140 including the heat exchange element 141, the uranium hexafluoride gas flowing through the collection container 50 exchanges heat, so that the uranium hexafluoride gas sublimes on the inner wall of the collection container 50, thereby realizing the collection of the uranium hexafluoride.

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

[0158] That is, the heat exchange element 141, the condensation pipeline 142 and the condensation circulating pump 143 constitute a heat exchange circulating loop, so as to further improve the heat exchange efficiency and improve the collection of the uranium hexafluoride. In addition, it is also beneficial to keep the collection container 50 at a constant temperature through the heat exchange device 140.

[0159] For example, the heat exchange device 140 can further include a medium container for storing the heat exchange medium.

[0160] Here, the condensation circulating pump 143 is used to provide power to circulate the heat exchange medium in the heat exchange circulating 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 arranging the tail gas treatment device 90.

[0162] In some embodiments, referring to Figure 1, the measuring device further comprises a tail gas treatment device 90, the pipeline assembly 10 further comprises a fourth pipeline unit 14, the fourth pipeline unit 14 is connected in parallel with the third pipeline unit 13, the tail gas treatment device 90 is arranged on the fourth pipeline unit 14, and the switch assembly 70 can selectively connect or close the fourth pipeline unit 14.

[0163] During vacuumizing, the fourth pipeline unit 14 and the third pipeline unit 13 can be closed by the control switch, so that the collecting container 50 is vacuumized through the third pipeline unit 13, and during the reaction, the fourth pipeline unit 14 and the third pipeline unit 13 can be connected by the control switch, and the region in which the third pipeline unit 13 and the fourth pipeline unit 14 are connected in parallel is closed, so that other gas is discharged through the vacuum device 60 after being treated by the tail gas treatment device 90, and thus, the possibility of polluting the environment or causing damage to people by the gas is reduced.

[0164] In some embodiments, referring to Figure 1 The tail gas treatment device 90 comprises an alkali absorption tank 91, and the alkali absorption tank 91 is used to store an alkali substance.

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

[0166] In this embodiment, by arranging the alkali absorption tank 91 storing the alkali substance, the fluorine gas not reacted is absorbed by the alkali substance after entering the alkali absorption tank 91, which is beneficial to reducing the corrosion of the fluorine gas to subsequent equipment and reducing the possibility of polluting the environment or causing damage to people.

[0167] In some embodiments, referring to Figure 1 The tail gas treatment device 90 comprises an activated carbon absorption tank 92, the activated carbon absorption tank 92 is arranged between the alkali absorption tank 91 and the vacuum device 60, and the activated carbon absorption tank 92 is provided with activated carbon.

[0168] In this embodiment, by arranging the activated carbon absorption tank 92 storing the activated carbon, other impurities or liquid are absorbed by the activated carbon tank after entering the activated carbon absorption tank 92, which is beneficial to drying and purifying the gas, thereby reducing the possibility of polluting the environment or causing damage to people.

[0169] In some embodiments, referring to Figure 1 The tail gas treatment device 90 comprises a buffer tank 93, and the buffer tank 93 is arranged between the alkali absorption tank 91 and the collecting container 50.

[0170] In this embodiment, the buffer tank 93 is arranged between the alkali absorption tank 91 and the collection container 50, and the buffer tank 93 can store the liquid in the alkali absorption tank 91 to some extent in the case of backflow, thereby effectively preventing the liquid from entering the collection container 50 and the reaction container 20, and further improving the reliability of the measuring device.

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

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

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

[0174] Embodiment One:

[0175] The operation steps are as shown above, except that the condition parameters are different. The specific parameters are as follows: 20 g of UO2 pellets are weighed and placed on the crucible 24, which is placed at the bottom of the container body 21 and sealed with the container end cover 22. The air in the reaction container 20 is replaced with nitrogen gas, and then the reaction container 20 is pumped to a vacuum. Then the heating furnace 80 is heated at a rate of 8 ℃ / min to 550 ℃, and after constant temperature for 1 hour, the reaction container 20 is pumped to a vacuum. Fluorine gas is rapidly introduced at a flow rate of 10 L / min to normal pressure, the valve is closed to maintain a closed environment in the reaction container 20, and the time t and the pressure value P at this time are recorded. Every 5 min, the pressure value at this time is recorded until the pressure does not change significantly.

[0176] The volume V of the reaction container 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 container 20 changes from the initial 101 kPa to 80.156 kPa, and the fluorine gas in the reaction container 20 decreases from 101 kPa to 38.468 kPa. The relationship between the reactant F2 partial pressure and the UO2 pellet reactant concentration is as follows.

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

[0178] Reactant F2 partial pressure / kPa UO2 pellet reaction rate mmol / min <!-- 10 -->]]> 101 1.92 81.32 0.98 60.24 0.37 50.25 0.11

[0179] Example 2

[0180] The operation steps are shown as above, except that the condition parameters are different, and the specific parameters are as follows: 20 g of UO2 pellets are taken and placed on the crucible 24, which is placed at the bottom of the reaction container 20, and the reaction container 20 is sealed with the reaction container 20 cover. Then the air in the reaction container 20 is replaced by nitrogen, and then the reaction container 20 is pumped to vacuum. Then the heating furnace 80 is heated at a temperature increasing rate of 8℃ / min to 600℃, and after constant temperature for 1 hour, the reaction container 20 is pumped to vacuum. Fluorine gas is rapidly introduced at a flow rate of 10 L / min to normal pressure, the valve is closed to maintain the sealed environment in the reaction container 20, and the time and pressure value at this time are recorded. Every 5 min, the pressure value at this time is recorded until the pressure has no obvious change. According to PV = nRT and the change of pressure, the reaction rate of the UO2 pellets can be calculated.

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

[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 experiment, it can be known that the fluorination rate of uranium dioxide can be accurately tested by the test method of the embodiments of the present application, and the reaction rate under different reactant concentrations can be tested.

[0185] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; 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 be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A device for measuring the rate of fluorination of uranium dioxide, characterized in that, The measurement device comprises: a pipeline assembly comprising a first pipeline unit, a second pipeline unit and a third pipeline unit; a reaction container comprising a container body and a container end cover, the container body is provided with a reaction cavity and an opening, the opening is communicated with the reaction cavity, the container end cover is arranged on the opening, and the reaction cavity is used for containing uranium dioxide; a first gas source communicated with the reaction cavity through the first pipeline unit, and the first gas source is used for supplying fluorine gas; a second gas source communicated with the reaction cavity through the second pipeline unit, and the second gas source is used for supplying inert gas; a collection container communicated with the reaction cavity through the third pipeline unit, and the collection container is used for collecting uranium hexafluoride; a vacuum device arranged on the third pipeline unit, and the vacuum device can be used for vacuumizing the collection container and the reaction container; a switch assembly capable of selectively connecting or closing the first pipeline unit, the second pipeline unit and the third pipeline unit; a heating furnace, at least part of the container body is arranged in the heating furnace; a tail gas treatment device comprising an alkali absorption tank, an activated carbon absorption tank and a buffer tank, the alkali absorption tank is used for storing alkaline substances, the activated carbon absorption tank is provided with activated carbon, the activated carbon absorption tank is arranged between the alkali absorption tank and the vacuum device, and the buffer tank is arranged between the alkali absorption tank and the collection container; a heat exchange device comprising a heat exchange element, the heat exchange element is arranged around the periphery of the collection container, the heat exchange element has a heat exchange medium inside, the heat exchange medium is used for exchanging heat with the uranium hexafluoride gas flowing through the collection container, so that the uranium hexafluoride gas sublimes on the inner wall of the collection container; a pressure gauge.

2. The measuring device of claim 1, wherein, The heat exchange device comprises a condensation pipeline and a condensation circulating pump, the heat exchange element has an inlet and an outlet, the two ends of the condensation pipeline are communicated with the inlet and the outlet respectively, and the condensation circulating pump is arranged on the condensation pipeline.

3. The measuring device of claim 1, wherein, The pipeline assembly further comprises a fourth pipeline unit, the fourth pipeline unit is connected in parallel on part of the third pipeline unit, the tail gas treatment device is arranged on 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 the temperature measuring thermocouple is arranged in the reaction cavity, and the temperature measuring thermocouple is used for detecting the temperature in the reaction cavity; and / or The material of the reaction container comprises Monel alloy; and / or The material of the pipeline assembly comprises at least one of stainless steel and red copper; and / or The measurement device comprises a mass flow meter, and the first pipeline unit is provided with the mass flow meter; and / or The measurement device comprises a mass flow meter, and the second pipeline unit is provided with the mass flow meter.

4. The measurement device according to claim 1, wherein The pipeline assembly comprises a fifth pipeline unit, the first pipeline unit and the second pipeline unit are communicated with the reaction cavity through the fifth pipeline unit, the fifth pipeline unit is provided with the pressure gauge; and / or, The gas outlet of the collection container is provided with the pressure gauge; and / or, The pressure gauge is made of fluorine gas corrosion resistant material.

5. A method of measuring the rate of fluorination of uranium dioxide, applied to the device for measuring the rate of fluorination of uranium dioxide according to any one of claims 1 to 4, characterized in that, The measurement method comprises: Placing the uranium dioxide to be reacted in the reaction cavity; Controlling the vacuum device to vacuumize the reaction cavity; Turning on the second gas source to supply inert gas to the reaction cavity, turning off the second gas source, and controlling the vacuum device to vacuumize the reaction cavity; Turning on the heating furnace to heat the reaction cavity to a preset temperature; Controlling the vacuum device to vacuumize the reaction cavity; Turning on the first gas source to supply fluorine gas to the reaction cavity until the reaction cavity is at normal pressure, and turning off the first gas source; Recording the reaction time and the gas pressure in the reaction cavity until the reaction is completed; Based on the reaction time and the gas pressure in the reaction cavity, the fluorination rate of the uranium dioxide is obtained.

6. The measurement method according to claim 5, characterized in that, The fluorination rate of the uranium dioxide is obtained based on the reaction time and the pressure change in the reaction cavity, which comprises: Taking the derivative of the curve of P versus t gives ; The rate of fluorination of the uranium dioxide is , ; Wherein, V is the volume of the reaction cavity, t is the reaction time, P is the gas pressure in the reaction cavity, R is a constant 8.314 J / (mol·K), and the temperature T is the preset temperature.

7. The measurement method according to claim 5, characterized by, The measurement device further comprises a heat exchange device, the heat exchange device comprises a heat exchange part, and the heat exchange part surrounds the side of the collection container; After the reaction is completed, the measurement method comprises: Turning on the heat exchange device, the heat exchange part exchanges heat with the uranium hexafluoride gas flowing through the collection container, so that the uranium hexafluoride gas sublimes on the inner wall of the collection container.

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