Dissolving device

Abstract

The invention relates to the technical field of nuclear reaction, and provides a dissolving device which is used for dissolving spent fuel and comprises a shell, a separator, a catalyst, an anode piece and a cathode piece. A dissolving cavity for accommodating a dissolving solution is formed in the shell; a containing cavity is formed in the partition part, the partition part is arranged in the dissolving cavity, an annular cavity is defined between the partition part and the cavity wall of the dissolving cavity, an opening is formed in the partition part, and the opening communicates with the containing cavity and the annular cavity; the catalyst is arranged in the annular cavity; the cathode part is arranged in the containing cavity, the anode part is located in the annular cavity, and the spent fuel is placed in the annular cavity so as to oxidize plutonium elements in the spent fuel. The dissolving device provided by the invention can improve the dissolving efficiency of the plutonium element in the spent fuel.

Description

Technical Field

[0001] The present application relates to the field of nuclear reaction technology, and in particular to a dissolution device. Background Art

[0002] Fast reactors are reactors that use fast neutrons to achieve chain fission reactions. They have the characteristics of greatly improving the utilization rate of radioactive element resources, transmuting long-lived waste and inherent safety. The development of fast reactor fuel cycles is a key link in achieving sustainable development of nuclear energy. Therefore, there is an urgent need for a device that can dissolve spent fuel.

[0003] In the related art, spent fuel such as MOX fuel is placed in a device containing nitric acid solution for dissolution. However, plutonium-rich insoluble residues are inevitably produced during the dissolution process, and the dissolution efficiency is low. Summary of the invention

[0004] In view of this, an embodiment of the present application hopes to provide a dissolution device that can improve the dissolution efficiency of plutonium in spent fuel.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the embodiment of the present application is implemented as follows:

[0006] The embodiment of the present application discloses a dissolution device for dissolving spent fuel, comprising:

[0007] The shell is formed with a dissolving cavity for containing the dissolving liquid;

[0008] A separator, wherein the separator is formed with a receiving cavity, the separator is arranged in the dissolving cavity, an annular cavity is defined between the separator and the cavity wall of the dissolving cavity, and the separator is formed with an opening, and the opening communicates the receiving cavity and the annular cavity;

[0009] A catalyst is arranged in the annular cavity;

[0010] An anode component and a cathode component, wherein the cathode component is arranged in the accommodating cavity, and the anode component is located in the annular cavity. The spent fuel is placed in the annular cavity to oxidize the plutonium element in the spent fuel.

[0011] In one embodiment, the anode member and the cathode member are both hollow barrel-shaped, the anode member is sleeved on the outside of the separator at intervals, and the cathode member is sleeved on the inside of the separator.

[0012] In one embodiment, the partition comprises a diaphragm and a supporting shell, the supporting shell forms the accommodating cavity, and the diaphragm is attached to the cavity wall of the accommodating cavity.

[0013] In one embodiment, the partition is fixedly disposed on the bottom wall of the dissolution chamber or the side wall of the dissolution chamber.

[0014] In one embodiment, the support shell is made of polytetrafluoroethylene; and / or,

[0015] The material of the shell is polytetrafluoroethylene.

[0016] In one embodiment, the housing comprises a shell and a cover, the shell is formed with the dissolution chamber and a mounting port communicating with the dissolution chamber, and the cover is used to open or close the mounting port;

[0017] The cover body is formed with an injection hole and an exhaust hole. When the cover body closes the mounting port, the injection hole and the exhaust hole are both connected to the dissolution chamber. Valves are provided at the injection hole and the exhaust hole.

[0018] In one embodiment, the dissolving device comprises a temperature sensor, and the temperature sensor is used to detect the temperature of the dissolving chamber.

[0019] In one embodiment, the dissolving device comprises a stirring member, and the stirring member is arranged in the dissolving chamber for stirring the dissolving liquid.

[0020] In one embodiment, the stirring element is a magnetic stirrer.

[0021] In one embodiment, the dissolving liquid is nitric acid, and the catalyst is monovalent silver ions or trivalent cerium ions.

[0022] The embodiment of the present application discloses a dissolution device. By providing a dissolution chamber in the shell, not only can the internal components such as the separator, cathode component and anode component be protected to a certain extent and their service life be improved, but also the introduction of impurities such as dust into the dissolution chamber can be reduced. By providing a separator in the dissolution chamber, a support is formed to form a receiving chamber, and part of the cathode component can be provided in the receiving chamber. In this way, on the one hand, support can be provided for the cathode component to better perform the electrochemical reaction; on the other hand, the situation that the spent fuel to be dissolved is driven and washed away by the dissolving liquid can be reduced; on the other hand, the cathode component and the anode component can be blocked to a certain extent to reduce the harm caused by direct contact between the two. By providing the anode component in the annular cavity and the cathode component in the receiving chamber, so that the annular cavity is formed into an anode chamber, and the receiving chamber is formed into a cathode chamber, and the spent fuel and the catalyst are both provided in the annular cavity, the receiving chamber and the annular cavity are connected by an opening, and the dissolving liquid can flow between the receiving chamber and the annular cavity through the opening, so that an oxidation reaction can occur at the anode component, and the catalyst can oxidize the plutonium element in the spent fuel into hexavalent amide ions. Based on the water-soluble property of amide ions, the dissolution efficiency of plutonium in spent fuel can be improved. That is to say, the dissolution device provided in the present application can realize indirect electrochemical oxidation to oxidize plutonium elements such as plutonium dioxide in spent fuel to facilitate subsequent dissolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of a dissolving device provided in an embodiment of the present application; wherein the cover body opens the installation opening;

[0024] Figure 2 A schematic structural diagram of a dissolving device provided in another embodiment of the present application, wherein a cover body closes the mounting opening.

[0025] Description of Reference Numerals

[0026] 100. Dissolving device; 1. Outer shell; 1a. Dissolving chamber; 1b. Ring chamber; 11. Shell; 11a. Mounting port; 12. Cover; 2. Partition; 2a. Accommodating chamber; 21. Diaphragm; 22. Support shell; 3. Anode member; 4. Cathode member; 5. Anode ear; 6. Cathode ear; 7. Stirring member. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0028] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The descriptions of "first", "second", etc. in the embodiments of the present application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly including at least one feature. In the description of the embodiments of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0029] The present application provides a dissolving device 100 for dissolving spent fuel. Figure 1 and Figure 2 The dissolution device 100 includes a shell 1, a separator 2, a catalyst, an anode member 3 and a cathode member 4. The shell 1 is formed with a dissolution chamber 1a for containing a dissolving liquid. The separator 2 is formed with a containing chamber 2a, and the separator 2 is arranged in the dissolution chamber 1a. An annular chamber 1b is defined between the separator 2 and the chamber wall of the dissolution chamber 1a. The separator 2 is formed with an opening, and the opening connects the containing chamber 2a and the annular chamber 1b. The catalyst is arranged in the annular chamber 1b. The cathode member 4 is arranged in the containing chamber 2a, the anode member 3 is located in the annular chamber 1b, and the spent fuel is placed in the annular chamber 1b to oxidize the plutonium in the spent fuel.

[0030] The dissolution device 100 provided in the present application, by providing a dissolution chamber 1a in the housing 1, can not only protect its internal components such as the separator 2, cathode component 4 and anode component 3 to a certain extent and improve their service life, but also reduce the introduction of dust and other impurities into the dissolution chamber 1a. By providing a separator 2 in the dissolution chamber 1a, a support is formed to form a receiving chamber 2a, and part of the cathode component 4 can be provided in the receiving chamber 2a. In this way, on the one hand, support can be provided for the cathode component 4 to better perform the electrochemical reaction; on the other hand, it can also reduce the situation where the spent fuel to be dissolved is driven and washed away by the dissolving liquid; on the other hand, the cathode component 4 and the anode component 3 can be blocked to a certain extent to reduce the harm caused by direct contact between the two. The anode member 3 is arranged in the annular cavity 1b, and the cathode member 4 is arranged in the accommodating cavity 2a, so that the annular cavity 1b is formed into an anode chamber, and the accommodating cavity 2a is formed into a cathode chamber, and the spent fuel and the catalyst are both arranged in the annular cavity 1b, and the accommodating cavity 2a and the annular cavity 1b are connected by an opening, and the dissolved liquid can flow between the accommodating cavity 2a and the annular cavity 1b through the opening, so that an oxidation reaction can occur at the anode member 3, and the catalyst can oxidize the plutonium element in the spent fuel into hexavalent amide ions. Based on the water-soluble property of amide ions, the dissolution efficiency of plutonium in spent fuel can be improved. That is to say, the dissolution device 100 provided in the present application can realize indirect electrochemical oxidation to oxidize plutonium elements such as plutonium dioxide in spent fuel to facilitate subsequent dissolution.

[0031] Exemplarily, in one embodiment, Figure 1 R1 can be in the inside-outside direction, and R2 can be in the top-bottom direction.

[0032] In one embodiment, the dissolving liquid is nitric acid, the catalyst is monovalent silver ions or trivalent cerium ions, the spent fuel can be a mixed fuel of plutonium uranium oxide (MOX), and the cathode member 4 and the anode member 3 can both be titanium-based platinum-plated metal. In this way, an electrolytic oxidation reaction occurs on the anode member 3:

[0033] Ag + →Ag 2+ (or Ce 3+ →Ce 4+ )

[0034]

[0035] NO3 is generated on the cathode 4 - Reduction reaction:

[0036]

[0037]

[0038] The overall reaction is:

[0039]

[0040] Here, the electrochemical method of dissolving the plutonium in the spent fuel has many advantages: it can be carried out at close to room temperature, requires a lower concentration of nitric acid, has a fast dissolution efficiency, which is twice that of the HNO3-HF dissolution method, and can achieve complete dissolution of plutonium oxide (PuO2).

[0041] It should be noted that the dissolution rate of PuO2 has little to do with its specific surface area and calcination temperature. It is only necessary to maintain the necessary Ag in the ring cavity 1b. 2+ (or Ce 4+ ) ion concentration, efficient dissolution can be achieved.

[0042] Exemplarily, in one embodiment, the concentration of nitric acid may be between 10 mol / L and 16 mol / L.

[0043] In one embodiment, the anode member 3 and the cathode member 3 are both hollow barrel-shaped, the anode member 3 is sleeved on the outside of the separator 2 at intervals, and the cathode member 4 is sleeved on the inside of the separator 2 .

[0044] In this way, by making the anode member 3 and the cathode member 4 into a hollow barrel shape, the anode member 3 is sleeved on the outside of the partition and the cathode member 4 is sleeved on the inside of the partition, the electrochemical mass transfer efficiency can be improved and the dissolution efficiency of the spent fuel can be further improved.

[0045] For example, in one embodiment, please refer to Figure 1 The dissolution device 100 includes an anode ear 5 and a cathode ear 6. The anode ear 5 and the anode component 3 can be connected by welding, and the cathode ear 6 and the cathode component 4 can be connected by welding. Then, the positive pole of the power supply is connected to the anode ear 5, and the negative pole of the power supply is connected to the cathode ear 6.

[0046] For example, in one embodiment, the dimensions of the anode member 3 are: the diameter may be 100 mm, and the height may be 90 mm. The dimensions of the anode member 3 are: the diameter may be 3 mm, and the height may be 50 mm.

[0047] For example, in one embodiment, the dimensions of the cathode member 4 are: 50 mm in diameter and 90 mm in height. The dimensions of the cathode tab 6 are: 3 mm in diameter and 50 mm in height.

[0048] In one embodiment, both the anode member 3 and the cathode member 4 are formed with openings that penetrate inward and outward directions. In this way, the dissolving liquid can flow through the openings, thereby improving the electrochemical mass transfer efficiency, promoting the electrochemical reaction, and improving the dissolution efficiency of the spent fuel.

[0049] In one embodiment, the number of openings is multiple, so that the anode member 3 and the cathode member 4 are in a mesh barrel shape.

[0050] Exemplarily, in one embodiment, the anode member 3 and the cathode member 4 may have planar mesh electrodes rolled up to form barrel-shaped electrodes.

[0051] In one embodiment, please refer to Figure 1 The dissolving device 100 includes a stirring member 7, which is disposed in the dissolving chamber 1a for stirring the dissolving liquid.

[0052] Exemplarily, the stirring member 7 can be arranged at the center bottom of the dissolution chamber 1a. Thus, by arranging the stirring member 7 to stir the dissolution liquid, on the one hand, the contact area and contact frequency between the dissolution liquid and the spent fuel can be increased, thereby accelerating the dissolution rate and reducing the error caused by uneven dissolution; on the other hand, stirring can ensure the uniformity of the dissolution liquid, reduce the occurrence of local concentrations that are too high or too low, and facilitate the electrochemical reaction.

[0053] In one embodiment, the stirring member 7 is a magnetic stirrer. Exemplarily, the magnet of the magnetic stirrer can be placed in the dissolution chamber 1a, and the magnet is rotated by magnetic force to stir the dissolution liquid, so that the spent fuel can be fully dissolved, while reducing the error caused by uneven dissolution; on the other hand, the magnetic stirrer stirs by magnetic force, so that the dissolution device 100 can be fully sealed during the dissolution process, reducing the situation where mechanical stirring requires strict sealing, so as to simplify the structure of the dissolution device 100.

[0054] In one embodiment, please refer to Figure 1 and Figure 2 The separator 2 includes a diaphragm 21 and a support shell 22. The support shell 22 forms a receiving cavity 2a. The diaphragm 21 is attached to the cavity wall of the receiving cavity 2a.

[0055] Exemplarily, the support shell 22 can be disposed in the dissolution chamber 1a, and the diaphragm 21 can be an anion diaphragm 21, which is attached to the wall of the accommodating chamber 2a. The support shell 22 can provide support for the cathode member 4 to reduce the situation where the spent fuel to be dissolved is washed away by the flow of the dissolving liquid, and the diaphragm 21 can selectively allow ions to pass through.

[0056] In one embodiment, the dimension between the bottom of the cathode member 4 and the bottom wall of the dissolution chamber 1a is about 25 mm.

[0057] For example, in one embodiment, the diaphragm 21 may be a porous ceramic, which is not only corrosion-resistant but also selectively allows ions to pass through.

[0058] Exemplarily, in one embodiment, the support shell 22 can be fixedly disposed on the bottom wall of the dissolution chamber 1a or the side wall of the dissolution chamber 1a. In this way, the connection strength between the support shell 22 and the outer shell 1 can be improved, and the shaking of the support shell 22 caused by the flow of the dissolved liquid can be reduced.

[0059] In one embodiment, the support shell 22 is made of polytetrafluoroethylene. In this way, the dissolving device can have the special effect of resisting nitric acid corrosion, thereby greatly improving the service life of the dissolving device 100 and stably promoting the progress of the electrochemical reaction.

[0060] In one embodiment, the material of the housing 1 is polytetrafluoroethylene. Here, by setting the material of the housing 1 to polytetrafluoroethylene, the nitric acid corrosion resistance of the housing 1 can be improved, thereby greatly improving the service life of the dissolving device 100, reducing the leakage of the dissolving solution from the housing 1, and improving the working stability.

[0061] In one embodiment, the support shell 22 is made of polytetrafluoroethylene, and the outer shell 1 is made of polytetrafluoroethylene. In this way, the service life of the dissolving device 100 can be further improved.

[0062] Exemplarily, in one embodiment, the shape of the support shell 22 is not limited. For example, the shape of the support shell 22 may be a cylindrical barrel. For example, its diameter may be 56 mm and its height may be 90 mm.

[0063] Exemplarily, in one embodiment, the shape of the shell 1 is not limited. For example, the shape of the shell 1 can be a cylindrical barrel. For example, its outer diameter can be 130 mm, the inner diameter can be 120 mm, and the height can be 130 mm. The effective volume of the shell 1 is 1 L, and the liquid level height is about 90 mm.

[0064] In one embodiment, please refer to Figure 1 and Figure 2 The housing 1 includes a shell 11 and a cover 12. The shell 11 is formed with a dissolving chamber 1a and a mounting port 11a communicating with the dissolving chamber 1a. The cover 12 is used to open or close the mounting port 11a.

[0065] In this way, on the one hand, the split installation method is adopted, which makes it easy to set the partition 2 and the spent fuel in the dissolution chamber 1a through the installation hole. After the installation is completed, the installation port 11a can be covered by the cover body 12; on the other hand, when it is necessary to inspect and repair the parts in the dissolution chamber 1a, the installation port 11a can also be opened by operating the cover body 12, which is convenient for inspection and repair.

[0066] In one embodiment, the cover body 12 and the shell body 11 can be connected by threads. For example, the dissolution chamber 1a is formed with one of an internal thread and an external thread on the outside or inside of the installation port 11a, and the cover body 12 is formed with the other of an internal thread and an external thread on the outside or inside. Through the threaded matching method, the connection strength and sealing between the cover body 12 and the shell body 11 can be improved, the overflow of the dissolved liquid from the installation port 11a can be reduced, and the pressure bearing capacity of the dissolution device 100 can be improved, and the working stability is good.

[0067] Illustratively, in one embodiment, the cover body 12 is formed with an anode ear hole and a cathode ear hole. The anode ear 5 can be fixed to the cover body 12 by a nut after passing through the anode ear hole, and the cathode ear 6 can also be fixed to the cover body 12 by a nut after passing through the cathode ear hole, so as to improve the connection stability between the cathode component 4 and the anode component 3, so as to stabilize the electrochemical reaction of the plutonium element, oxidize it into amide ions and dissolve it, thereby improving the dissolution efficiency.

[0068] In one embodiment, the cover body 12 is formed with an injection hole and an exhaust hole. When the cover body 12 closes the mounting port 11a, the injection hole and the exhaust hole are both connected to the dissolution chamber 1a, and valves are provided at the injection hole and the exhaust hole.

[0069] Exemplarily, the dissolution device 100 includes an injection tube and an exhaust tube, wherein a portion of the injection tube is disposed in the dissolution chamber 1a, and another portion of the injection tube passes through the injection hole, and a corresponding valve can be disposed on the injection tube at the injection hole; a portion of the exhaust tube can be disposed in the dissolution chamber 1a, and another portion of the exhaust tube passes through the exhaust hole, and a corresponding valve can be disposed on the exhaust tube at the exhaust hole.

[0070] In this way, when it is necessary to add a dissolving liquid and a catalyst to the dissolving chamber 1a, the valve at the injection hole can be opened to sample the dissolving chamber 1a through the injection hole. By setting the exhaust hole and the corresponding valve, the risk of gas generated by the reaction being retained in the dissolving chamber 1a and causing pressure holding can be reduced, and the safety is high.

[0071] Exemplarily, in one embodiment, the sum of the volumes of the dissolved liquid and the spent fuel does not exceed 900 ml, so that more space can be left for temporary storage of the gas produced by the reaction.

[0072] For example, in one embodiment, the diameter of the exhaust hole may be 6 mm, so that the gas in the dissolving chamber 1a can be discharged relatively quickly.

[0073] In one embodiment, the dissolution device 100 includes a temperature sensor, and the temperature sensor is used to detect the temperature of the dissolution chamber 1a.

[0074] Exemplarily, the cover body 12 may be formed with a temperature measuring hole. When the cover body 12 closes the mounting port 11a, the temperature measuring hole is connected to the dissolution chamber 1a. A temperature sensor may be disposed in the temperature measuring hole. The temperature measuring end of the temperature sensor may measure the temperature in the dissolution chamber 1a through the temperature measuring hole, so as to obtain the electrochemical reaction state in a timely manner.

[0075] Exemplarily, in one embodiment, the operation of dissolving spent fuel using the dissolution device 100 of the present application is as follows:

[0076] 1. The separator 21 can be cut and then wrapped around the outside of the cathode member 4, and can be fixed with a cable tie, and then placed in the support shell 22;

[0077] 2. First, place an appropriate amount of spent fuel and magnetons in the dissolution chamber 1a, and then place the support shell 22 containing the cathode member 4 in the dissolution chamber 1a. Then, add an appropriate amount of dissolving liquid such as nitric acid and catalyst to the annular chamber 1b in sequence through the injection hole on the cover 12, and the sum of the volume of the dissolving liquid and the spent fuel does not exceed 900ml. Then, add an appropriate amount of nitric acid to the containing chamber 2a, and the volume of nitric acid does not exceed 120ml;

[0078] 3. Check the sealing of the dissolving device 100 to ensure that there is no liquid leakage;

[0079] 4. Start the magnetic stirrer and adjust the speed. The magnet starts to rotate to fully mix the reactants.

[0080] 5. Connect the anode tab 5 of the anode component 3 and the cathode tab 6 of the cathode component 4 to the positive and negative electrodes of a DC power supply respectively, and then turn on the power supply;

[0081] 6. Control reaction conditions: according to the reaction requirements, the output current of the power supply, the speed of the magneton and the reaction time can be controlled;

[0082] 7. During the electrochemical dissolution process, gas will be produced at the cathode, so the valve at the exhaust hole on the cover 12 of the dissolution device 100 should always be kept open;

[0083] 8. Stop the reaction: Stop the reaction in time according to the reaction requirements and situation;

[0084] 9. Separation of products: After the reaction is completed, turn off the DC power supply, stop the magnetic stirrer, and slowly open the cover 12. Finally, the reaction products are separated, extracted, purified, and other processes according to the reaction requirements.

[0085] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. All modifications, equivalent substitutions, improvements, etc. within the spirit and principles of the present application are included in the protection scope of the present application.

Claims

1. A dissolving device for dissolving spent fuel, characterized in that: include: The shell is formed with a dissolving cavity for containing the dissolving liquid; A separator, wherein the separator is formed with a receiving cavity, the separator is arranged in the dissolving cavity, an annular cavity is defined between the separator and the cavity wall of the dissolving cavity, and the separator is formed with an opening, and the opening communicates the receiving cavity and the annular cavity; A catalyst is arranged in the annular cavity; An anode component and a cathode component, wherein the cathode component is arranged in the accommodating cavity, and the anode component is located in the annular cavity. The spent fuel is placed in the annular cavity to oxidize the plutonium element in the spent fuel.

2. The dissolving device according to claim 1, characterized in that: The anode member and the cathode member are both hollow barrel-shaped, the anode member is sleeved on the outside of the separator at intervals, and the cathode member is sleeved on the inside of the separator.

3. The dissolving device according to claim 1, characterized in that: The separator comprises a diaphragm and a supporting shell, the supporting shell forms the accommodating cavity, and the diaphragm is attached to the cavity wall of the accommodating cavity.

4. The dissolving device according to claim 3, characterized in that: The partition is fixedly arranged on the bottom wall of the dissolution chamber or the side wall of the dissolution chamber.

5. The dissolving device according to claim 3, characterized in that: The support shell is made of polytetrafluoroethylene; and / or, The material of the shell is polytetrafluoroethylene.

6. The dissolving device according to claim 1, characterized in that: The housing comprises a shell and a cover, the shell is formed with the dissolution chamber and a mounting port communicating with the dissolution chamber, and the cover is used to open or close the mounting port; The cover body is formed with an injection hole and an exhaust hole. When the cover body closes the mounting port, the injection hole and the exhaust hole are both connected to the dissolution chamber. Valves are provided at the injection hole and the exhaust hole.

7. The dissolving device according to claim 1, characterized in that: The dissolving device comprises a temperature sensor, and the temperature sensor is used to detect the temperature of the dissolving chamber.

8. The dissolving device according to claim 1, characterized in that: The dissolving device comprises a stirring member, which is arranged in the dissolving chamber and is used for stirring the dissolving liquid.

9. The dissolving device according to claim 8, characterized in that: The stirring element is a magnetic stirrer.

10. The dissolving device according to claim 1, characterized in that: The dissolving liquid is nitric acid, and the catalyst is monovalent silver ions or trivalent cerium ions.

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