Device and method for measuring fluorination rate of spent fuel short section

Abstract

The embodiment of the present application discloses a kind of measuring device and measuring method of fluorination rate of spent fuel short section, measuring device includes pipeline assembly, reaction vessel, first gas source, second gas source, collection device, vacuum device, switch assembly and heating furnace.Pipeline assembly includes first pipeline unit, second pipeline unit and third pipeline unit.The container body of reaction vessel is provided with reaction cavity.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 device is communicated with reaction cavity, and collection device includes at least one collection container, and collection container stores absorption solution, and the uranium hexafluoride flowing in the collection container can be dissolved in absorption solution.Vacuum device can be used at least to vacuumize collection device and reaction vessel.Switch assembly can be used at least to selectively communicate or close pipeline assembly.At least part of container body is arranged in heating furnace.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorination of spent fuel short section, and particularly to a device and method for measuring fluorination rate of spent fuel short section. 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. The 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 processing 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 the spent fuel short section. SUMMARY

[0003] Therefore, the embodiments of the present application aim to provide a device and method for measuring fluorination rate of spent fuel short section 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 fluorination rate of spent fuel short section, which comprises:

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

[0007] A reaction container, which comprises 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, which is in communication with the reaction cavity through the first pipeline unit, and is used for supplying fluorine gas;

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

[0010] A collection device, which is in communication with the reaction cavity through the third pipeline unit, and comprises at least one collection container, the collection container stores an absorption solution, and uranium hexafluoride flowing through the collection container can be dissolved in the absorption solution;

[0011] A vacuum device, which is arranged on the third pipeline unit and located downstream of the collection device, and can be used at least for vacuumizing the collection device and the reaction container;

[0012] a switch assembly, which is capable of selectively connecting or disconnecting the first pipe unit, the second pipe unit and the third pipe unit;

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

[0014] In some embodiments, the number of the collection containers is at least two, and the at least two collection containers are arranged in parallel.

[0015] In some embodiments, the collection device comprises a circulation pipe and a circulation pump, two ends of the circulation pipe are connected to the collection containers respectively, and the circulation pump is arranged in the circulation pipe.

[0016] In some embodiments, the measuring device further comprises a tail gas treatment device, which is arranged between the collection device and the vacuum device.

[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 for detecting 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 pipe 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 pipe unit is provided with the mass flow meter.

[0021] In some embodiments, the measuring device comprises a mass flow meter, and the second pipe 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 for storing alkali 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 collection device.

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

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

[0027] In some embodiments, the pressure gauge is arranged between the reaction container and the collection device.

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

[0029] The embodiments of the present application also provide a measurement method of fluorination rate of spent fuel short section, which is applied to a measurement device of fluorination rate of spent fuel short section, and the measurement device comprises a reaction container, a first gas source, a second gas source, a vacuum device, a collection device and a heating furnace, and the measurement method comprises the following steps:

[0030] Placing the spent fuel short section 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] Collecting uranium hexafluoride through the collection container;

[0036] Turning on the first gas source to supply fluorine gas to the reaction cavity;

[0037] Recording a reaction time, and sampling the absorption solution at a regular time to obtain the concentration of uranium in the absorption solution until the reaction is completed;

[0038] Obtaining the fluorination rate of the spent fuel short section based on the concentration of uranium in the absorption solution.

[0039] In some embodiments, the obtaining of the fluorination rate of the spent fuel short section based on the concentration of uranium in the absorption solution comprises:

[0040] Obtaining the amount of substance of uranium based on the maximum concentration of uranium in the absorption solution and the volume of the collection container;

[0041] The fluorination rate of the spent fuel short section is v,

[0042] Wherein, t is the reaction time, and S is the total surface area of the spent fuel short section reacting with fluorine gas.

[0043] In some embodiments, the number of the collection containers is at least two, the at least two collection containers are arranged in parallel, the collection device comprises a circulation pipeline and a circulation pump, two ends of the circulation pipeline are respectively connected to the collection containers, and the circulation pump is arranged in the circulation pipeline;

[0044] The collecting of the uranium hexafluoride by the collection containers comprises:

[0045] One of the collection containers is opened to collect the uranium hexafluoride, and the collection container is closed after a preset time;

[0046] The next collection container is opened to collect the uranium hexafluoride.

[0047] The measuring device for the fluorination rate of the short spent fuel piece in the embodiments of the present application places the short spent fuel piece to be reacted in a reaction cavity of a reaction container, discharges the air in the reaction cavity and fills the reaction cavity with nitrogen by 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 opened to heat the reaction cavity to a reaction temperature, and the vacuum device is controlled to vacuumize the reaction cavity. Then the collection container is opened to collect the uranium hexafluoride by the collection container. Then the first gas source is opened to supply fluorine gas to the reaction cavity. In this way, the reaction time can be recorded, the absorption solution can be sampled at a fixed time, the concentration of uranium in the absorption solution can be obtained, and the fluorination rate of the short spent fuel piece can be obtained based on the concentration of uranium in the absorption solution. The measuring device is simple and reliable in structure, and can measure the fluorination rate of the short spent fuel piece under the condition of high-concentration fluorine gas. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The structure diagram of the measuring device for the fluorination rate of the short spent fuel piece in some embodiments of the present application;

[0049] Figure 2 The flowchart of the measuring method for the fluorination rate of the short spent fuel piece in some embodiments of the present application.

[0050] REFERENCE SIGNS

[0051] 10, pipeline assembly; 11, first pipeline unit; 12, second pipeline unit; 13, third pipeline unit; 14, fourth pipeline unit; 20, reaction container; 21, container body; 22, container end cover; 23, reaction cavity; 30, first gas source; 40, second gas source; 50, collection device; 51, collection container; 52, circulation pipeline; 53, circulation pump; 60, vacuum device; 70, switch assembly; 80, heating furnace; 90, tail gas treatment device; 91, alkali absorption tank; 92, activated carbon absorption tank; 110, temperature measuring thermocouple; 120, mass flowmeter; 130, pressure gauge. DETAILED DESCRIPTION

[0052] 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 clarify the technical solutions of the present application, 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 effort belong to the protection scope of the present application.

[0053] 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 “plurality” is two or more, unless otherwise explicitly and specifically limited.

[0054] In this document, the reference to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the 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 all refer to the same embodiment, nor is it necessarily mutually exclusive or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0055] In the description of the embodiments of the present application, the term “and / or” is only used to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character “ / ” in this document generally represents an “or” relationship between the front and rear associated objects.

[0056] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms “mounting”, “connection”, “connection”, “fixing” and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0057] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical term "contact" should be interpreted in a broad sense, which can be direct contact or contact through an intermediate medium layer, which can be contact between two objects in contact without interaction force or contact between two objects in contact with interaction force.

[0058] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] The present application provides a measuring device for the fluorination rate of a short section of spent fuel.

[0060] 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 device 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, and the container end cover 22 is arranged on the opening. The reaction cavity 23 is used to accommodate 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 to supply 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 to supply inert gas. The collection device 50 is in communication with the reaction cavity 23 through the third pipeline unit 13, and the collection device 50 includes at least one collection container 51. The collection container 51 stores an absorption solution, and uranium hexafluoride flowing through the collection container 51 can be dissolved in the absorption solution. The vacuum device 60 is arranged on the third pipeline unit 13 and is located downstream of the collection device 50. The vacuum device 60 can at least be used to vacuumize the collection device 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 arranged in the heating furnace 80.

[0061] Here, the pipeline assembly 10 is mainly used to connect various parts of the measuring device.

[0062] 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 uranium dioxide and fluorine gas.

[0063] Exemplarily, the reaction container 20 includes the container body 21 and the container end cover 22.

[0064] The container body 21 is provided with the reaction cavity 23 and the opening, and uranium dioxide can be accommodated in the reaction cavity 23 through the opening.

[0065] Here, the container body 21 is in the shape of a pot, that is, the container body 21 is, for example, a reaction pot.

[0066] The container end cover 22 covers the opening of the container body 21 and is connected to the container body 21.

[0067] 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 to the container body 21, the container end cover 22 has good air tightness, so as to be beneficial to improving the reaction reliability between the uranium dioxide and the fluorine gas.

[0068] Exemplarily, the reaction container 20 includes a crucible arranged in the container body 21 and used for carrying the uranium dioxide.

[0069] Exemplarily, the first gas source 30 can include a fluorine gas bottle used for storing the fluorine gas.

[0070] Exemplarily, the first gas source 30 can include an inert gas bottle used for storing an inert gas, which includes but is not limited to nitrogen.

[0071] Exemplarily, the spent fuel short section can include uranium dioxide pellets and / or uranium dioxide powder.

[0072] Here, the second gas source 40 is used for supplying the inert gas, which is beneficial to discharging the air in the reaction cavity 23 and can improve the measurement accuracy of the fluorination rate by filling the inert gas in the reaction cavity 23 in the heating stage.

[0073] 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 device 50.

[0074] Exemplarily, the switch assembly 70 includes but is not limited to a switch valve, a one-way valve and the like.

[0075] 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.

[0076] The collection device 50 includes at least one collection container 51, which means that the collection device 50 can include one collection container 51 or multiple collection containers 51.

[0077] The multiple in the embodiments of the present application means two or more.

[0078] The collection container 51 stores an absorption solution used for absorbing the uranium hexafluoride.

[0079] For example, the absorption solution can be water.

[0080] Of course, the absorbing solution can also be any other solution capable of dissolving uranium hexafluoride.

[0081] The device for measuring the fluorination rate of spent fuel short segments according to this application embodiment places the spent fuel short segments to be reacted in the reaction chamber 23 of the reaction vessel 20. Through the cooperation of the second gas source 40 and the vacuum device 60, the air in the reaction chamber 23 is purged and filled with nitrogen. The reaction chamber 23 is kept sealed, and then the heating furnace 80 is turned on to heat the reaction chamber 23 to the reaction temperature. The vacuum device 60 is then used to evacuate the reaction chamber 23. Then, the collection container 51 is opened to collect uranium hexafluoride. Then, the first gas source 30 is turned on to supply fluorine gas to the reaction chamber 23. In this way, the reaction time can be recorded, and the absorption solution can be sampled periodically to obtain the concentration of uranium in the absorption solution until the reaction is complete. Based on the concentration of uranium in the absorption solution, the fluorination rate of the spent fuel short segments can be obtained. This measuring device has a simple and reliable structure and can measure the fluorination rate of spent fuel short segments under high-concentration fluorine gas conditions.

[0082] In some embodiments, please refer to Figure 1 The number of collection containers 51 is at least two, and at least two collection containers 51 are set in parallel.

[0083] It should be noted that uranium hexafluoride will exhibit a specific color when dissolved in the absorption solution. Thus, when the amount of uranium hexafluoride dissolved in a collection container 51 reaches a certain level, the color will become darker, which is not conducive to determining whether uranium hexafluoride continues to dissolve and also presents a sensitivity issue in detection.

[0084] In this embodiment, by setting at least two collection containers 51 connected in parallel, uranium hexafluoride can be collected sequentially through different collection containers 51, which helps to improve the collection efficiency of the collection containers 51, and thus helps to improve the measurement accuracy of the fluorination rate of the short segment of spent fuel. In addition, the color of the absorption solution can be used to determine whether the reaction has ended, which further helps to improve the measurement accuracy and efficiency of the fluorination rate of the short segment of spent fuel.

[0085] In some embodiments, please refer to Figure 1 The collection device 50 includes a circulation pipeline 52 and a circulation pump 53. The two ends of the circulation pipeline 52 are respectively connected to the collection container 51, and the circulation pump 53 is disposed in the circulation pipeline 52.

[0086] That is, the collection container 51, the circulation pipeline 52, and the circulation pump 53 constitute an absorption solution circulation loop, so that the absorption efficiency is further improved, thereby improving the collection of uranium hexafluoride.

[0087] Here, the circulation pump 53 is configured to provide power for the circulation of the absorption solution in the absorption solution circulation loop.

[0088] It should be noted that the other gas generated by the reaction of the spent fuel short section and the fluorine gas can be directly discharged through the vacuum device 60, or can be treated through the tail gas treatment device 90.

[0089] In some embodiments, referring to Figure 1 , the measuring device further comprises a tail gas treatment device 90, and the tail gas treatment device 90 is arranged between the collection device 50 and the vacuum device 60.

[0090] During the reaction, the other gas can be treated through the tail gas treatment device 90 and then discharged through the vacuum device 60, so that the possibility of polluting the environment or causing damage to people is reduced.

[0091] 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 configured to store an alkaline substance.

[0092] It should be noted that the specific type of the alkaline substance is not limited herein. For example, the alkaline substance is a lime solution.

[0093] In this embodiment, by arranging the alkali absorption tank 91 storing the alkaline substance, the fluorine gas that is not reacted enters the alkali absorption tank 91 and is absorbed by the alkaline substance, which is beneficial to reduce the corrosion of the fluorine gas to the subsequent equipment, and can reduce the possibility of polluting the environment or causing damage to people.

[0094] In some embodiments, referring to Figure 1 , the tail gas treatment device 90 comprises an activated carbon absorption tank 92, and the activated carbon absorption tank 92 is arranged between the alkali absorption tank 91 and the vacuum device 60.

[0095] In this embodiment, by arranging the activated carbon absorption tank 92 storing the activated carbon, the other impurities or liquids enter the activated carbon absorption tank 92 and are absorbed by the activated carbon tank, which is beneficial to dry and purify the gas, thereby reducing the possibility of polluting the environment or causing damage to people.

[0096] In some embodiments, referring to Figure 1 , the tail gas treatment device 90 comprises a buffer tank, and the buffer tank is arranged between the alkali absorption tank 91 and the collection device 50.

[0097] In this embodiment, by setting the buffer tank and setting the buffer tank between the alkali absorption tank 91 and the collection device 50, in the case of generating reverse suction, the buffer tank can to some extent buffer the liquid in the alkali absorption tank 91, thereby effectively preventing the liquid from entering the collection device 50 and the reaction container 20, which is conducive to further improving the reliability of the measuring device.

[0098] In some embodiments, referring to Figure 1 The reaction container 20 includes a temperature measuring thermocouple 110, at least part of the temperature measuring thermocouple 110 is arranged in the reaction cavity 23, and is used to detect the temperature in the reaction cavity 23.

[0099] In this embodiment, by setting the temperature measuring thermocouple 110, the actual temperature of the reaction tank is measured, thereby facilitating the improvement of the measurement accuracy of the fluorination rate of uranium dioxide.

[0100] In some embodiments, referring to Figure 1 The material of the reaction container 20 includes Monel alloy.

[0101] Here, by setting the material of the reaction container 20 to include Monel alloy, the structural strength of the reaction container 20 is improved, and the corrosion resistance to fluorine gas and the like is also improved, further improving the reliability of the reaction container 20.

[0102] In some embodiments, referring to Figure 1 The material of the pipeline assembly 10 includes at least one of stainless steel and red copper.

[0103] Exemplarily, the material of the pipeline assembly 10 includes 316 stainless steel.

[0104] In this embodiment, by setting the material of the pipeline assembly 10 to include at least one of stainless steel and red copper, the structural strength of the pipeline assembly 10 is improved, and the corrosion resistance to fluorine gas and the like is also improved, further improving the reliability of the pipeline assembly 10.

[0105] In some embodiments, referring to Figure 1 The measuring device includes a pressure gauge 130.

[0106] Here, the pressure gauge 130 is used to detect the pressure, and by detecting and controlling the pressure, the measurement accuracy of the fluorination rate is improved.

[0107] Exemplarily, the pressure gauge 130 can be a pressure gauge.

[0108] Exemplarily, the pipeline assembly 10 comprises a fourth pipeline unit 14, the first pipeline unit 11 and the second pipeline unit 12 are communicated with the reaction cavity 23 through the fourth pipeline unit 14, and the fourth pipeline unit 14 is provided with a pressure gauge 130.

[0109] That is, the first pipeline unit 11 and the second pipeline unit 12 are communicated with the fourth pipeline unit 14 in parallel.

[0110] In this way, the fluorine gas enters the reaction cavity 23 through the first pipeline unit 11 and the fifth pipeline unit in sequence. The inert gas enters the reaction cavity 23 through the second pipeline unit 12 and the fourth pipeline unit 14 in sequence.

[0111] The fourth pipeline unit 14 is provided with the pressure gauge 130, and the fourth pipeline unit 14 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.

[0112] In some embodiments, referring to Figure 1 , the pressure gauge 130 is arranged between the reaction container 20 and the collecting device 50.

[0113] In this way, by arranging the pressure gauge 130 between the reaction container 20 and the collecting device 50, the gas pressure between the reaction container 20 and the collecting device 50 can be measured.

[0114] In some embodiments, referring to Figure 1 , the pressure gauge 130 is made of a fluorine-resistant material.

[0115] 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 can be improved, and the reliability of the pressure gauge 130 is further improved.

[0116] In some embodiments, referring to Figure 1 , the measuring device comprises a mass flow meter 120, and the first pipeline unit 11 is provided with the mass flow meter 120.

[0117] In this way, the flow of fluorine gas can be controlled, and the measurement accuracy of the fluorination rate is further improved.

[0118] In some embodiments, referring to Figure 1 , the measuring device comprises a mass flow meter 120, and the second pipeline unit 12 is provided with the mass flow meter 120.

[0119] In this way, the flow of inert gas can be controlled, and the measurement accuracy of the fluorination rate is further improved.

[0120] The embodiment of the present application also provides a method for measuring the fluorination rate of a spent fuel short section, which is applied to a device for measuring the fluorination rate of a spent fuel short section, and the device comprises a reaction container 20, a first gas source 30, a second gas source 40, a vacuum device 60, a collection device 50 and a heating furnace 80. Please refer to Figure 2 The method comprises the following steps:

[0121] S210: placing the spent fuel short section to be reacted into the reaction cavity;

[0122] Exemplarily, please refer to Figure 1 The reaction container 20 comprises a container body 21 and a container end cover 22.

[0123] 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.

[0124] Here, the container body 21 is in the shape of a pot, that is, the container body 21 is, for example, a reaction pot.

[0125] The container end cover 22 covers the opening of the container body 21 and is connected with the container body 21.

[0126] Exemplarily, the container end cover 22 is in sealed cooperation with the container body 21, that is, the container end cover 22 has good air tightness after being connected with the container body 21, so as to be beneficial to improving the reaction reliability between the spent fuel short section and the fluorine gas.

[0127] Exemplarily, the reaction container 20 comprises a crucible, which is arranged in the container body 21 and is used for carrying the spent fuel short section.

[0128] Exemplarily, the crucible is arranged at the bottom of the container body 21.

[0129] Here, please refer to Figure 1 The container body 21, the first gas source 30, the second gas source 40, the collection device 50, an alkali absorption tank 91, an activated carbon absorption tank 92, a buffer tank and the vacuum device 60 are communicated through a pipeline assembly 10.

[0130] S220: controlling the vacuum device to vacuumize the reaction cavity;

[0131] Exemplarily, please refer to Figure 1 The switch assembly 70 comprises a first valve, which is arranged on the third pipeline unit 13 between the reaction container 20 and the collection device 50.

[0132] The switch assembly 70 comprises a second valve, which is arranged on the fourth pipeline unit 14.

[0133] The vacuum device 60 is opened, and then the switch assembly 70 between the vacuum device 60 and the reaction container 20 is opened in sequence, so as to vacuumize the reaction container 20.

[0134] Step S230: opening the second gas source, supplying inert gas to the reaction cavity, closing the second gas source, and controlling the vacuum device to vacuumize the reaction cavity;

[0135] After the reaction container 20 is vacuumized, the first valve between the reaction container 20 and the collection device 50 is closed. The second gas source 40 is opened, the flow rate of the mass flow meter 120 on the second pipeline unit 12 is set, the second valve is opened, and the reaction container 20 is vacuumized to normal pressure, which is repeated three times.

[0136] Step S240: opening the heating furnace, and heating the reaction cavity to a preset temperature;

[0137] The reaction container 20 is heated by the heating furnace 80, and the reaction cavity 23 is heated to a preset temperature.

[0138] Here, the preset temperature is, for example, a reaction temperature.

[0139] Exemplarily, the measuring device includes a pipeline heating belt, which can be opened while the reaction container 20 is heated by the heating furnace 80.

[0140] Step S250: controlling the vacuum device to vacuumize the reaction cavity;

[0141] After the reaction cavity 23 is heated to a preset temperature, the vacuum device 60 is controlled to vacuumize the reaction cavity 23.

[0142] Step S260: collecting uranium hexafluoride by the collection device;

[0143] The collection device 50 includes at least one collection container 51, which means that the collection device 50 can include one collection container 51 or multiple collection containers 51.

[0144] The multiple in the embodiments of the present application means two or more.

[0145] The collection container 51 stores an absorption solution, which is used to absorb uranium hexafluoride.

[0146] Exemplarily, the absorption solution can be water.

[0147] Of course, the absorption solution can also be other solutions that can dissolve uranium hexafluoride.

[0148] Step S270: opening the first gas source, and supplying fluorine gas to the reaction cavity;

[0149] The first gas source 30 is opened, the fluorine gas mass flow meter 120 is set, the second valve is opened, and fluorine gas is filled into the reaction container 20. The second valve is closed to ensure that the gas pressure in the device is balanced.

[0150] Step S280: Record the reaction time, and take samples of the absorption solution at regular time intervals to obtain the concentration of uranium in the absorption solution until the reaction is completed.

[0151] At 5 min, start sampling, and use a centrifuge tube to take about 5 ml of absorption solution. Then, take samples at every 5 min interval, and number the samples respectively.

[0152] Step S290: Obtain the fluorination rate of the spent fuel short section based on the concentration of uranium in the absorption solution.

[0153] In some embodiments, referring to Figure 1 , obtaining the fluorination rate of the spent fuel short section based on the concentration of uranium in the absorption solution includes:

[0154] Obtaining the amount of substance of generated uranium based on the maximum concentration of uranium in the absorption solution and the volume of the collection container 51;

[0155] The fluorination rate of the spent fuel short section is v,

[0156] Wherein, t is the reaction time, and S is the total surface area of the spent fuel short section reacting with fluorine gas.

[0157] The reaction occurring during the experiment is:

[0158] UO2(s)+3F2(g)→UF6(g)+O2(g)

[0159] The uranium concentration c (unit: g / L) in the collection device 50 is determined by analyzing the highest uranium concentration in the spent fuel short section sample. The volume of the collection device 50 is V (unit: L), and the amount of substance of generated uranium is m = cV (unit: g). The mass of uranium reacted is equal to the mass of generated uranium, and the total surface area of the spent fuel short section reacting with fluorine gas is S (unit: cm 2 ). Therefore, the fluorination reaction rate of the spent fuel short section can be expressed as:

[0160]

[0161] The reaction rate v refers to the mass of the spent fuel short section reacting with fluorine gas per unit area per unit time, and the unit is g / (min·cm2).

[0162] In some embodiments, referring to Figure 1The number of the collection containers 51 is at least two, the at least two collection containers 51 are arranged in parallel, the collection device 50 comprises a circulation pipeline 52 and a circulation pump 53, two ends of the circulation pipeline 52 are respectively communicated to the collection containers 51, and the circulation pump 53 is arranged in the circulation pipeline 52;

[0163] The uranium hexafluoride is collected through the collection container 51, which comprises:

[0164] One of the collection containers 51 is opened to collect the uranium hexafluoride, and the collection container 51 is closed after a preset time;

[0165] The next collection container 51 is opened to collect the uranium hexafluoride.

[0166] Sampling is started every first preset time, about 5 ml of the absorption solution is taken by using a centrifugal tube, and then sampling is performed every first preset time, and the samples are numbered respectively.

[0167] When the reaction approaches the end point, or when the interval second preset time is reached, the next collection container 51 is opened to collect the uranium hexafluoride.

[0168] It should be noted that the first preset time is not limited herein. Exemplarily, the first preset time can be a point value of any one of 2 min, 2 min, 5 min, 10 min, 20 min or a point value between any two of them.

[0169] It should be noted that the second preset time is not limited herein. Exemplarily, the second preset time can be a point value of any one of 30 min, 60 min, 120 min, 180 min, 240 min or a point value between any two of them.

[0170] It should be noted that the uranium hexafluoride dissolved in the absorption solution will present a specific color. Thus, when the amount of the uranium hexafluoride dissolved by one collection container 51 reaches a certain amount, the color will be deeper, which is not conducive to determining whether the uranium hexafluoride continues to dissolve, and there is a problem of detection sensitivity.

[0171] In this embodiment, by arranging at least two collection containers 51, the at least two collection containers 51 are arranged in parallel, so that the uranium hexafluoride can be collected through different collection containers 51 in turn, thereby being conducive to improving the collection efficiency of the collection container 51, and further being conducive to improving the measurement accuracy of the fluorination rate of the short section of the spent fuel. In addition, it can be determined through the color of the absorption solution whether the reaction is finished, which is further conducive to improving the measurement accuracy and efficiency of the fluorination rate of the short section of the spent fuel.

[0172] In some embodiments, please refer to Figure 1The collecting device 50 comprises a circulating pipeline 52 and a circulating pump 53. Two ends of the circulating pipeline 52 are respectively connected to the collecting container 51, and the circulating pump 53 is arranged in the circulating pipeline 52.

[0173] That is, the collecting container 51, the circulating pipeline 52 and the circulating pump 53 form an absorption solution circulating loop, so that the absorption efficiency is further improved, thereby improving the collection of uranium hexafluoride.

[0174] Here, the circulating pump 53 is used to provide power to circulate the absorption solution in the absorption solution circulating loop.

[0175] It should be noted that other gases generated by the reaction of the spent fuel short section and the fluorine gas can be directly discharged through the vacuum device 60, or can be treated through the tail gas treatment device 90.

[0176] In some embodiments, referring to Figure 1 The measuring device further comprises a tail gas treatment device 90 arranged between the collecting device 50 and the vacuum device 60.

[0177] During the reaction, the other gases can be treated through the tail gas treatment device 90 and then discharged through the vacuum device 60, so as to reduce the possibility of polluting the environment or causing damage to people.

[0178] In some embodiments, referring to Figure 1 The tail gas treatment device 90 comprises an alkali absorption tank 91 for storing an alkaline substance.

[0179] It should be noted that the specific type of the alkaline substance is not limited here. For example, the alkaline substance is an alkali lime solution.

[0180] In this embodiment, by arranging the alkali absorption tank 91 storing the alkaline substance, the fluorine gas not reacted enters the alkali absorption tank 91 and is absorbed by the alkaline substance, which is beneficial to reduce the corrosion of the fluorine gas to the subsequent equipment and can reduce the possibility of polluting the environment or causing damage to people.

[0181] In some embodiments, referring to Figure 1 The tail gas treatment device 90 comprises an activated carbon absorption tank 92 provided with activated carbon, and the activated carbon absorption tank 92 is arranged between the alkali absorption tank 91 and the vacuum device 60.

[0182] In this embodiment, by arranging the activated carbon absorption tank 92 storing the activated carbon, other impurities or liquids enter the activated carbon absorption tank 92 and are absorbed by the activated carbon tank, which is beneficial to dry and purify the gas, thereby reducing the possibility of polluting the environment or causing damage to people.

[0183] In some embodiments, referring to Figure 1 , the tail gas treatment device 90 includes a buffer tank, which is arranged between the alkali absorption tank 91 and the collection device 50.

[0184] In this embodiment, by arranging the buffer tank and arranging the buffer tank between the alkali absorption tank 91 and the collection device 50, in the case of reverse suction, the buffer tank can to some extent buffer the liquid in the alkali absorption tank 91, thereby effectively preventing the liquid from entering the collection device 50 and the reaction container 20, and facilitating further improvement of the reliability of the measuring device.

[0185] After the reaction is completed, the fluorine gas mass flow meter 120 is closed, the nitrogen gas mass flow meter 120 is opened, and nitrogen gas is continuously introduced for a period of time, the residual fluorine gas in the device is discharged into the collection device 50 for absorption, and then all the valves are closed, the heating furnace 80 is closed, and natural cooling is performed. When the temperature of the reaction container 20 reaches room temperature, the fluorination residue on the crucible is taken out, and the fluorination residue and the sampled sample are analyzed.

[0186] The measurement method of the fluorination rate of uranium dioxide provided by the embodiments of the present application is further described below through two specific embodiments.

[0187] Embodiment one:

[0188] The operation steps are as shown above, except that the condition parameters are different, and the specific parameters are: 21g spent fuel short section is weighed and placed on the crucible, which is placed at the bottom of the reaction container 20 and sealed with the container end cover 22. Then the air in the reaction cavity 23 is replaced by nitrogen gas, and then the reaction cavity 23 is pumped to vacuum. Then the reaction container 20 is heated at a heating rate of 8℃ / min to 550℃, and after constant temperature for 1 hour, fluorine gas is introduced at a flow rate of 300ml / min, and at the same time, the vacuum device 60 is used for pumping. The gas passes through one of the collection containers 51, and the pressure in the collection container 51 is kept stable. The sample is taken every 10 minutes, and after 120 minutes, the collection container 51 is replaced with another collection container 51, and the sampling is continued until the reaction is completed. After the reaction is completed, the remaining residue and the sampled sample are analyzed.

[0189] The contact area of the spent fuel short section with fluorine gas in the operation is 2.27cm 2 , the pressure in the reaction container 20 during the reaction changes in the range of 80kPa-101kPa, the fluorine gas partial pressure remains unchanged during the reaction, and the reaction is carried out for a total of 180min. The calculated average fluorination reaction rate is 0.044g / (min·cm 2 ).

[0190] Embodiment two:

[0191] The operation steps are the same as those shown above, except that the condition parameters are different, and the specific parameters are as follows: 14 g of spent fuel short section is taken and placed on the crucible, which is placed at the bottom of the reaction container 20 and sealed with the container end cover 22. The air in the reaction container 20 is replaced with nitrogen, and then the reaction container 20 is pumped to vacuum. Then the reaction container 20 is heated at a rate of 8 ℃ / min to 650 ℃, and after constant temperature for 1 hour, the mixed gas of fluorine and nitrogen is introduced at a total flow rate of 300 ml / min, wherein the fluorine flow rate is 100 ml / min and the nitrogen flow rate is 200 ml / min, and at the same time the vacuum device 60 is used for gas pumping. The gas passes through one of the collection containers 51, and the pressure in the collection container 51 is kept stable. The sample is taken every 5 min, and after 60 min, the collection container 51 is replaced with another collection container 51 until the reaction is completed. After the reaction is completed, the remaining residue and the sample are analyzed. According to the uranium content in the sample, the total amount of UF6 generated can be calculated, and the fluorination reaction rate of the spent fuel short section can be calculated.

[0192] The contact area of the spent fuel short section and fluorine in the operation is 2.27 cm 2 The pressure in the reaction container 20 during the reaction changes in the range of 80 kPa to 101 kPa, and the fluorination reaction rate calculated by measuring for 120 min is 0.26 g / (min·cm 2 ).

[0193] According to the above experiment, it can be seen that the test method of the embodiment of the present application can accurately test the fluorination rate of the spent fuel short section, and the reaction rate under different reactant concentrations can be tested.

[0194] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the above 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 fluorination rate of a spent fuel slug, characterized in that, The measuring 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 device communicated with the reaction cavity through the third pipeline unit, and the collection device comprises at least one collection container, and an absorption solution is stored in the collection container, and uranium hexafluoride flowing through the collection container can be dissolved in the absorption solution; a vacuum device arranged on the third pipeline unit and located downstream of the collection device, and the vacuum device can be used at least for vacuumizing the collection device and the reaction container; a switch assembly used at least for selectively connecting or closing the first pipeline unit, the second pipeline unit and the third pipeline unit; a heating furnace, and at least part of the container body is arranged in the heating furnace.

2. The measuring device of claim 1, wherein, The number of the collection containers is at least two, and the at least two collection containers are arranged in parallel.

3. The measuring device of claim 1, wherein, The collection device comprises a circulating pipeline and a circulating pump, two ends of the circulating pipeline are communicated with the collection containers respectively, and the circulating pump is arranged on the circulating pipeline.

4. The measuring device of claim 1, wherein, The measuring device further comprises a tail gas treatment device arranged between the collection device and the vacuum device; 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 measuring device comprises a mass flow meter, and the first pipeline unit is provided with the mass flow meter; and / or The measuring device comprises a mass flow meter, and the second pipeline unit is provided with the mass flow meter.

5. The measuring device of claim 4, wherein, The tail gas treatment device comprises an alkali absorption tank used for storing alkaline substances.

6. The measuring device of claim 5, wherein, The tail gas treatment device comprises an activated carbon absorption tank, 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 arranged between the alkali absorption tank and the collection device.

7. The measuring device of claim 1, wherein, The measuring device comprises a pressure gauge; The pipeline assembly comprises a fourth pipeline unit, the first pipeline unit and the second pipeline unit are communicated with the reaction cavity through the fourth pipeline unit, and the fourth pipeline unit is provided with the pressure gauge; and / or The pressure gauge is arranged between the reaction container and the collection device; and / or The pressure gauge is arranged between the reaction container and the collection device; and / or The pressure gauge is made of fluorine corrosion resistant material.

8. A method for measuring the fluorination rate of a spent fuel slug, applied to the measuring device for the fluorination rate of a spent fuel slug according to any one of claims 1 to 7, characterized in that, The measuring device comprises a reaction container, a first gas source, a second gas source, a vacuum device, a collection device and a heating furnace, and the measuring method comprises the following steps: Placing the spent fuel short section to be reacted into the reaction cavity; Controlling the vacuum device to vacuumize the reaction cavity; Opening the second gas source to supply inert gas to the reaction cavity, closing the second gas source, and controlling the vacuum device to vacuumize the reaction cavity; Opening the heating furnace to heat the reaction cavity to a preset temperature; Controlling the vacuum device to vacuumize the reaction cavity; Collecting uranium hexafluoride through the collection device; Opening the first gas source to supply fluorine gas to the reaction cavity; Recording the reaction time, and sampling the absorption solution at regular time intervals to obtain the concentration of uranium in the absorption solution until the reaction is completed; Based on the concentration of uranium in the absorption solution, obtaining the fluorination rate of the spent fuel short section.

9. The measurement method according to claim 8, characterized in that, The method for obtaining the fluorination rate of the spent fuel short section based on the concentration of uranium in the absorption solution comprises the following steps: Based on the maximum concentration of uranium in the absorption solution and the volume of the collection container, obtaining the amount of substance of the generated uranium; The fluorination rate of the spent fuel short section is v , ; Wherein, t is the reaction time, and S is the total surface area of the spent fuel short section reacting with fluorine gas.

10. The measurement method according to claim 8, characterized by, The number of the collection containers is at least two, and the at least two collection containers are arranged in parallel, the collection device comprises a circulation pipeline and a circulation pump, two ends of the circulation pipeline are respectively connected to the collection containers, and the circulation pump is arranged in the circulation pipeline; The method for collecting uranium hexafluoride through the collection container comprises the following steps: Opening one of the collection containers to collect uranium hexafluoride, and closing the collection container after a preset time; Opening the next collection container to collect uranium hexafluoride.

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