Raman analysis method and system for simulating real-time detection of chemical form of iodine in spent fuel head end dissolving process
Through Raman analysis methods and systems, the chemical form of iodine during the dissolution of the first end of spent fuel is detected in real time, solving the problem of iodine residual pollution in spent fuel treatment, and providing scientific data to improve iodine removal technology.
Patent Information
- Application Number
- CN202411818275.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-04-29
AI Technical Summary
During the post-treatment process of spent fuel water method, radioactive iodine remains in the nitric acid dissolving solution, contaminating the entire solvent extraction system, resulting in problems such as damage to the radiation of organic solvents, increasing the generation of organic iodine, and excessive radioactivity of the tail end of spent fuel treatment. The prior art lacks effective iodine chemical morphology recognition methods and removal techniques.
Raman analysis methods and systems are used to simulate the dissolution process of the spent fuel at the first end. By putting spent fuel simulated dissolving solution into the reaction vessel, heating and sampling, Raman spectroscopy is used to analyze the content changes of various chemical forms of iodine, and the chemical forms of iodine are detected and identified in real time.
Real-time monitoring and identification of the chemical morphology of iodine during the dissolution of spent fuel at the first end is achieved, scientific data is provided for iodine removal in spent fuel treatment, improved the understanding of the chemical morphology changes of iodine, and helped to formulate effective removal strategies.
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Figure CN119901723A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of spent fuel post-processing, and in particular relates to a Raman analysis method and system for real-time detection of iodine chemical forms in a simulated spent fuel head-end dissolution process. Background Art
[0002] Radioactive iodine is an inevitable product of nuclear fission reaction and one of the polluting elements that need to be paid attention to in the reprocessing of spent fuel. During the aqueous reprocessing of spent fuel, most of the iodine will enter the exhaust gas, but some of it will remain in the nitric acid solution. This part of the radioactive iodine remaining in the solution will enter the downstream extraction process and pollute the entire solvent extraction system, leading to problems such as organic solvent irradiation damage, increased generation of organic iodine, and excessive iodine radioactivity at the end of spent fuel treatment. Accurate identification of iodine chemical forms is the key to achieving efficient removal of radioactive iodine. However, there is still a lack of in-depth understanding of the chemical forms of iodine and its evolution. To date, residual iodine is still an important problem that plagues the reprocessing process. Developing new iodine chemical form identification methods, accurately understanding the evolution mechanism of iodine chemical forms in the solution, and proposing new iodine removal technologies are the key to breaking through the bottleneck problem of poor iodine removal efficiency in spent fuel dissolution. Raman spectroscopy is an analytical method that provides molecular intrinsic information such as vibration and rotation that is closely related to molecular structure. It is an important tool for the identification of functional groups and microstructure research of substances, and has great advantages in molecular specific identification. According to literature reports and standard sample testing, the Raman spectra of various forms of iodine are very different, making it possible to use Raman spectroscopy to identify the chemical form of iodine during the first-end dissolution process. Summary of the invention
[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.
[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.
[0005] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a Raman analysis method for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution.
[0006] In order to solve the above technical problems, the present invention provides the following technical solutions, including:
[0007] Spent fuel simulated dissolution liquid is added to the reaction vessel and heated to 85-95°C for reaction. Samples are taken at various time points of the reaction. The samples are analyzed by Raman spectroscopy to determine the changes in the content of various chemical forms of iodine and to identify the progress of the dissolution reaction.
[0008] As a preferred embodiment of the Raman analysis method for real-time detection of iodine chemical forms in the simulated spent fuel head-end dissolution process of the present invention, the simulated liquid includes nitric acid and potassium iodide, wherein the concentration of nitric acid is 3-6 mol / L, and the concentration of potassium iodide is 1-5 g / L.
[0009] As a preferred solution of the Raman analysis method for real-time detection of iodine chemical forms in the simulated spent fuel head-end dissolution process of the present invention, the heating rate is 10°C / min.
[0010] Another object of the present invention is to overcome the deficiencies in the prior art and provide a system for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution.
[0011] In order to solve the above technical problems, the present invention provides the following technical solutions, including:
[0012] Port 1 of the reactor is connected to a gas cylinder, with a gas flow meter installed in the middle; port 2 is installed with a thermometer sleeve and a temperature probe; port 3 is connected to a sampling needle; port 4 is connected to a gas washing bottle;
[0013] The sampling needle is connected to the NC port of the three-way solenoid valve, the common port of the three-way solenoid valve is connected to the Raman spectrum test cell through a pipeline, and then connected to the ON port of the dispensing syringe pump through a pipeline, and the OFF port of the dispensing syringe pump is immersed in the cleaning agent solvent; the NO port of the three-way solenoid valve is connected to the waste liquid receiving bottle; the dispensing syringe pump and the solenoid valve in the system are remotely controlled through the program, and the timed sampling test of the dissolved liquid is realized according to the sampling time plan.
[0014] As a preferred solution of the system for real-time detection of iodine chemical forms in the process of simulating spent fuel head-end dissolution described in the present invention, the reactor is a glass container.
[0015] As a preferred solution of the system for real-time detection of iodine chemical forms in the process of simulating spent fuel head-end dissolution described in the present invention, the gas washing bottle contains a receiving agent of sodium thiosulfate or sodium hydroxide aqueous solution.
[0016] As a preferred solution of the system for real-time detection of iodine chemical forms in the process of simulating spent fuel head-end dissolution described in the present invention, the material of the sampling needle includes 316 stainless steel, glass, and polytetrafluoroethylene.
[0017] As a preferred solution of the system for real-time detection of iodine chemical forms in the process of simulating spent fuel head-end dissolution described in the present invention, a gas flow meter is installed between the port 1 and the gas cylinder.
[0018] As a preferred solution of the system for real-time detection of iodine chemical forms in the process of simulating spent fuel head-end dissolution described in the present invention, the gas flow rate of the port 1 is 0.05-1 L / min.
[0019] In view of the above problems, the present invention designs an experimental device for simulating the dissolution process of spent fuel head end, which is used to simulate the chemical form change of iodine in the dissolution process of spent fuel head end. The device is designed with a gas inlet, which can simulate the chemical form change of iodine under the condition of gas existence.
[0020] In order to realize the real-time analysis of iodine chemical forms in the simulated spent fuel head-end dissolution process, the technical solution adopted in the present invention is Raman spectroscopy.
[0021] The solution is as follows:
[0022] 1) A glass container is used as a reaction container and an exhaust gas receiving device, and a heating device is provided outside to achieve temperature regulation of the dissolved liquid.
[0023] 2) A spent fuel simulation solution is added inside the fuel tank. The simulation solution contains nitric acid and potassium iodide. The concentration of nitric acid can be adjusted within the range of 3 to 6 mol / L, and the concentration of potassium iodide can be adjusted within the range of 1 to 5 g / L.
[0024] 3) After completing the above two steps, start heating, set the heating rate to 10°C / min, and maintain the temperature after reaching a certain temperature, the temperature range is 85-95°C.
[0025] 4) Take samples through the sampling port at each time point of the reaction, and the sampler should be made of polytetrafluoroethylene material.
[0026] 5) The sample is transferred into a glass capillary, and the Raman spectrum of the dissolved solution is collected using a Raman spectrometer.
[0027] 6) The content changes of various chemical forms of iodine are analyzed by Raman spectroscopy to identify the progress of the dissolution reaction and provide guidance for the time node of the dissolution solution regulation.
[0028] Nitrogen oxides can regulate the chemical form of iodine in the solution, but existing data only provide data on the change in the final iodine removal rate, and the actual change in the form of iodine in the solution is still unknown. In the present invention, a nitrogen oxide mixed gas can be introduced through the remaining gas loading port, and the actual regulating effect of nitrogen oxides on the chemical form of iodine in the solution can be obtained through sampling and Raman spectroscopy analysis.
[0029] To achieve the above object, the present invention also discloses a real-time online detection device for iodine chemical forms in a simulated spent fuel head-end dissolution process. Figure 2 The device realizes liquid control through a three-channel distributing syringe pump. Specifically: the sampler of the glass reactor sampling port is connected to the NC port of the three-way solenoid valve, the common port of the three-way solenoid valve is connected to the Raman spectrum test pool through a pipeline, and then connected to the ON port of the distributing syringe pump through a pipeline, and the OFF port of the distributing syringe pump is immersed in the cleaning agent solvent. The NO port of the three-way solenoid valve is connected to a waste liquid receiving bottle. As shown in the figure. The distributing syringe pump and solenoid valve in the device can be remotely controlled by the program, and the timed sampling test of the dissolved liquid can be realized according to the sampling time plan.
[0030] During the test, the dissolved liquid is pumped into the test pool by the pump, and after the test is completed, it is pushed back to the reactor by the pump. Then the cleaning process begins: the cleaning liquid is pumped into the OFF port of the dispensing syringe pump and then discharged from the ON port. At this time, the first solenoid valve is switched to the NO port, and the test pool can be cleaned.
[0031] Beneficial effects of the present invention:
[0032] (1) The present invention proposes an in-situ real-time Raman analysis method to monitor and identify the chemical forms of iodine and its dynamic changes in the dissolution process in real time during the first-end dissolution process, providing scientific data on the chemical forms and evolution mechanism of iodine during the first-end dissolution of spent fuel.
[0033] (2) The present invention designs an experimental device to simulate the dissolution process of the first end of spent fuel, and builds an in-situ real-time sampling and analysis device. By combining it with a Raman spectrometer, it realizes the real-time Raman analysis of the iodine chemical forms in the process of simulating the dissolution of the first end of spent fuel, and detects the time Raman spectra of various iodine chemical forms. The device can realize the online analysis of the iodine form evolution under gas control conditions by loading different gases.
[0034] (3) The present invention provides a Raman analysis method and device for real-time detection of iodine chemical forms during the first-end dissolution of spent fuel, thereby improving the understanding of iodine chemical forms during the first-end dissolution of spent fuel. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:
[0036] Figure 1 This is a diagram of a reaction device for simulating the spent fuel head-end dissolution process of the present invention.
[0037] Figure 2 This is a schematic diagram of the real-time online detection system for iodine chemical forms in the process of simulating the dissolution of spent fuel head end according to the present invention.
[0038] Figure 3 These are Raman spectra of the dissolved liquid at the simulated spent fuel head end at different times.
[0039] Figure 4 The Raman spectra thermal images of the first-end dissolved liquid at different times obtained by the real-time online detection system. DETAILED DESCRIPTION
[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.
[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0042] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0043] The raw materials used in the present invention are all commercially available unless otherwise specified.
[0044] Example 1
[0045] This embodiment provides a Raman analysis method for real-time detection of iodine chemical forms in a simulated spent fuel head-end dissolution process, specifically:
[0046] (1) Experimental device simulating the dissolution process of spent fuel head end, see Figure 1 , specifically:
[0047] A four-mouth round-bottom flask is used as a reactor, port 1 is used to connect the gas, and a gas flowmeter is installed in the middle; port 2 is used to install a thermometer sleeve and a temperature probe; port 4 is used to connect the gas washing bottle (containing the receiving agent sodium thiosulfate or sodium hydroxide aqueous solution), with a conversion head and a polytetrafluoroethylene pipeline in the middle; port 3 is used to connect the sampling needle, and the material of the needle is selected to be resistant to strong acid and corrosion, such as 316 stainless steel or PTFE tube or glass.
[0048] A program temperature controller is used as a heating device, and temperature sensing is achieved through a thermometer probe.
[0049] (2) A spent fuel simulation solution is added internally. The simulation solution contains nitric acid and potassium iodide. The concentration of nitric acid can be adjusted within the range of 4 mol / L, and the concentration of potassium iodide can be adjusted within the range of 5 g / L.
[0050] (3) Start heating, set the heating rate to 10°C / min, and maintain the temperature at 90°C.
[0051] (4) Sampling is performed through the sampling port at various time points of the reaction, and the sampler is made of polytetrafluoroethylene.
[0052] (5) The sample was transferred to a glass capillary tube, and the Raman spectrum of the dissolved solution was collected using a Raman spectrometer. 10x objective lens, 532nm laser, 60mW, collection time 1s, accumulation 3 times.
[0053] (6) Raman spectroscopy is used to analyze the changes in the content of various chemical forms of iodine and identify the progress of the dissolution reaction. Figure 3 It can be seen that as the dissolution reaction proceeds, the characteristic Raman peaks of various forms of iodine appear in turn, including 110-116 cm -1 、140~148cm -1 170~178cm -1 200~220cm -1 Etc., representing that the form of iodine is gradually transformed from polyiodide anion to iodine molecule form, providing visual guidance for the change of chemical form of iodine during the dissolution process.
[0054] Example 2
[0055] The difference between this embodiment and embodiment 1 is that the reactor port 1 is used to access the gas connection gas, and a gas flow meter is installed in the middle; the gas is a mixture of nitrogen oxides, oxygen, and air, and the gas flow rate ranges from 0.05 to 1 L / min.
[0056] Example 3
[0057] The difference between this embodiment and embodiment 1 is that the sampler of the sampling port of the glass reactor is connected to the NC port of the three-way solenoid valve, and the common port of the three-way solenoid valve is connected to the Raman spectrum test pool through a pipeline. The test pool adopts a quartz dish formed by optical glue, which contains a 1.5mm*2mm channel and is connected to the ON port of the dispensing injection pump through a pipeline. The OFF port of the dispensing injection pump is immersed in the cleaning agent solvent, and the cleaning agent is water. The NO port of the three-way solenoid valve is connected to a waste liquid receiving bottle, such as Figure 2 .
[0058] The dissolved liquid is pumped into the test pool by the pump, and after the test is completed, it is pushed back to the reactor by the pump. Then the cleaning process begins: the cleaning liquid is pumped into the OFF port of the dispensing syringe pump and then discharged from the ON port. At this time, the three-way solenoid valve is switched to the NO port to complete the cleaning of the test pool, thus completing a test cycle.
[0059] The test procedure is to test every 5 minutes in the first 60 minutes and every 10 minutes in the next 90 minutes.
[0060] Raman spectroscopy is used to analyze the changes in the content of various chemical forms of iodine and to identify the changes in the chemical forms of iodine during the dissolution reaction. Figure 4 The various iodine chemical forms (characteristic peaks 110-116 cm -1 、140~148cm -1 170~178cm -1 200~220cm -1 ) content, as the dissolution reaction proceeds, the iodine form changes from the polyiodine anion content to the iodine molecular form, which gradually increases and then evaporates quickly from the solution. This test result more clearly shows the change in the chemical form of iodine during the simulated spent fuel dissolution process.
[0061] In summary, the present invention designs an experimental device to simulate the dissolution process of the first end of spent fuel, and builds a set of in-situ real-time sampling and analysis devices. By combining with a Raman spectrometer, the real-time Raman analysis of the iodine chemical forms in the process of simulating the dissolution of the first end of spent fuel is realized, and the time Raman spectra of various iodine chemical forms are detected. The device can realize the online analysis of the iodine form evolution under gas control conditions by loading different gases.
[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
Claims
1. A Raman analysis method for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution, characterized in that: include, Spent fuel simulated dissolution liquid is added to the reaction vessel and heated to 85-95°C for reaction. Samples are taken at various time points of the reaction. The samples are analyzed by Raman spectroscopy to determine the changes in the content of various chemical forms of iodine and to identify the progress of the dissolution reaction.
2. The Raman analysis method for real-time detection of iodine chemical forms in the simulated spent fuel head-end dissolution process according to claim 1, characterized in that: The simulated liquid includes nitric acid and potassium iodide, wherein the concentration of the nitric acid is 3-6 mol / L, and the concentration of the potassium iodide is 1-5 g / L.
3. The Raman analysis method for real-time detection of iodine chemical forms in the simulated spent fuel head-end dissolution process according to claim 1, characterized in that: The heating rate is 10°C / min.
4. A system for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution, characterized in that: include, Port 1 of the reactor is connected to a gas cylinder, with a gas flow meter installed in the middle; port 2 is installed with a thermometer sleeve and a temperature probe; port 3 is connected to a sampling needle; port 4 is connected to a gas washing bottle; The sampling needle is connected to the NC port of the three-way solenoid valve, the common port of the three-way solenoid valve is connected to the Raman spectrum test cell through a pipeline, and then connected to the ON port of the dispensing syringe pump through a pipeline, and the OFF port of the dispensing syringe pump is immersed in the cleaning agent solvent; the NO port of the three-way solenoid valve is connected to the waste liquid receiving bottle; the dispensing syringe pump and the solenoid valve in the system are remotely controlled through the program, and the timed sampling test of the dissolved liquid is realized according to the sampling time plan.
5. The system for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution as claimed in claim 4, characterized in that: The reactor is a glass container.
6. The system for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution as claimed in claim 4, characterized in that: The gas washing bottle contains a receiving agent, sodium thiosulfate or sodium hydroxide aqueous solution.
7. The system for real-time detection of iodine chemical forms during simulated spent fuel head-end dissolution as claimed in claim 4, characterized in that: The materials of the sampling needle include 316 stainless steel, glass, and polytetrafluoroethylene.
8. The Raman analysis method for real-time detection of iodine chemical forms in a simulated spent fuel head-end dissolution process as claimed in claim 4, characterized in that: A gas flow meter is installed between the port 1 and the gas cylinder.
9. The Raman analysis method for real-time detection of iodine chemical forms in the simulated spent fuel head-end dissolution process as claimed in claim 8, characterized in that: The gas flow rate of the port 1 is 0.05-1 L / min.