System and method for collecting and processing waste liquid from metal fuel pellet metallographic sample preparation

Abstract

A kind of metal fuel core metallographic sample preparation waste liquid collecting and processing system and method for special metal, including polishing device, waste liquid storage pool, polypropylene filter cotton, resin unit, purified liquid collection and reuse box;Polishing device is connected by pipeline waste liquid storage pool, polypropylene filter cotton is loaded in waste liquid storage pool;Waste liquid storage pool is connected by pipeline resin unit, and resin unit is connected purified liquid collection and reuse box.It uses ion exchange resin system, effectively removes the solubility radioactivity that traditional filter cotton cannot handle, and the radioactivity level of purified liquid is significantly reduced, to meet the requirements of reuse or further processing.Through polypropylene filter cotton, the solid waste residue containing nuclear material is efficiently recycled, nuclear safety is guaranteed, and resource reuse is realized.

Description

Technical Field

[0001] This invention relates to the field of metallographic sample preparation technology for nuclear fuel cores, and specifically to a system and method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores. Background Technology

[0002] In the preparation of uranium-plutonium metal fuel cores, metallographic sample preparation is a crucial step in quality control. Metallographic analysis, as an effective means of observing the microstructure of nuclear fuel cores, provides vital information for optimizing core preparation process parameters. This sample preparation process involves polishing (generating waste containing radioactive materials) and microstructure visualization. Water and polishing agents play indispensable roles in metallographic polishing, jointly ensuring the smoothness and gloss of the sample surface, laying a solid foundation for subsequent accurate metallographic analysis. However, these processes also result in the generation of complex-component waste liquids with high radioactivity levels at the metallographic preparation stage. Due to their complex composition and radioactivity exceeding limits, these waste liquids do not meet direct discharge standards and lack dedicated treatment and discharge channels. Traditional filter cotton is inefficient, only able to trap larger waste residues in the waste liquid, unable to effectively recover soluble important nuclides, and simultaneously generating a large amount of secondary waste, resulting in the waste of nuclear materials.

[0003] Uranium-plutonium metal fuel waste differs from conventional nuclear fuel waste, presenting greater challenges in its treatment. In waste disposal, deep conversion is required; in recycling, the target is not simply uranium, but plutonium, a highly radioactive and toxic element. Therefore, the process is complex, requires extremely high levels of protection, and is very costly. Traditional resin purification columns or single-stage purification columns are inefficient for removing uranium and plutonium; while evaporation / precipitation methods suffer from high energy consumption, low efficiency, and the generation of enriched waste. In summary, this waste liquid is characterized by complex composition, high radioactivity, significant treatment difficulty, high safety risks, and the need for nuclear material recovery. Therefore, developing and applying an efficient, safe, and economical system for the collection, treatment, and resource recovery of nuclear fuel core metallographic sample preparation waste liquid is particularly urgent. Summary of the Invention

[0004] The purpose of this invention is to provide a system and method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores, which solves the problems of low processing efficiency, inability to effectively remove dissolved radionuclides, high operating costs, large amount of secondary waste, and insufficient recovery of nuclear materials in the existing technology.

[0005] The technical solution of the present invention is as follows: A waste liquid collection and treatment system for metallographic sample preparation of special metal fuel cores, comprising a polishing device, a waste liquid storage tank, polypropylene filter cotton, a resin unit, and a purified liquid collection and reuse tank; the polishing device is connected to the waste liquid storage tank through a pipeline, and the waste liquid storage tank is filled with polypropylene filter cotton; the waste liquid storage tank is connected to the resin unit through a pipeline, and the resin unit is connected to the purified liquid collection and reuse tank.

[0006] There is a mechanical pump between the waste liquid storage tank and the resin unit.

[0007] There is a check valve between the resin unit and the purified liquid collection and reuse tank.

[0008] The purified liquid collection and reuse tank is connected to the evaporation and concentration device, which is used to evaporate and concentrate excess purified liquid that cannot be reused or purified liquid that has accumulated after multiple reuses.

[0009] The resin unit comprises a primary resin column and a secondary resin column connected in series. The primary resin column is made of polystyrene-ethylenedibenzene copolymer, nitrogen-containing porous polymer, and acrylic acid-divinylbenzene skeleton. The secondary resin column is made of polystyrene-divinylbenzene skeleton (with quaternary ammonium groups) and styrene-vinylpyridine-divinylbenzene copolymer. Both the primary and secondary resin columns adopt a bottom-in, top-out method.

[0010] The purification liquid collection and reuse tank is also connected to the polishing device. The purification liquid collected in the purification liquid collection and reuse tank is reused for the initial cleaning of the core sample and the polishing grinding disc.

[0011] A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores includes the following steps:

[0012] S1: The grinding and polishing device grinds and polishes the core. This process uses water and polishing agent and produces waste liquid containing radioactive waste residue and dissolved nuclides.

[0013] S2: Waste liquid is transported from the grinding and polishing device to the waste liquid storage tank through a stainless steel pipeline, and then filtered and recycled through polypropylene filter cotton 3.

[0014] S3: The filtered waste liquid in the waste liquid storage tank is transported through pipelines to the primary resin column to remove the main radioactive uranium ion nuclides in the waste liquid; subsequently, the waste liquid passes through the secondary resin column to remove residual radioactive plutonium ion nuclides.

[0015] S4: The waste liquid purified by the resin unit is transported to the purified liquid collection and reuse tank.

[0016] In step S3, a mechanical pump transports the filtered waste liquid from the waste liquid storage tank to the primary resin column through a pipeline at a controllable flow rate of 0.25 L / min. Both the primary and secondary resin columns adopt a bottom-in, top-out method, with the flow rate controlled at 1.5 column volumes.

[0017] In step S4, the purified liquid in the purified liquid collection and reuse tank is used for core grinding and polishing in step S1.

[0018] It also includes S5, where excess purified liquid that cannot be reused or purified liquid accumulated after multiple reuses is processed by an evaporation and concentration device, with an evaporation rate preferably of 1.5L / h and a heating temperature controlled at 80℃.

[0019] The significant advantages of this invention are as follows: This system employs an ion exchange resin system, effectively removing soluble radionuclides that traditional filter cotton cannot handle, significantly reducing the radioactivity level of the purified liquid to meet the requirements for reuse or further treatment. The efficient recovery of solid waste containing nuclear materials through polypropylene filter cotton ensures nuclear safety and achieves resource reuse. The regenerable nature of the resin is a major economic breakthrough for this system, significantly reducing long-term operating consumable costs and the amount of secondary solid waste generated (mainly saturated resin, with a volume much smaller than waste filter cotton or evaporation residue) compared to disposable filter cotton or energy-intensive pure evaporation / precipitation methods. The purified liquid can be safely reused in the cleaning process, reducing fresh water consumption and the total amount of waste liquid to be treated, making it both environmentally friendly and economical. The evaporation device efficiently concentrates non-reusable liquids, greatly reducing the volume of high-level radioactive waste that ultimately needs to be disposed of. The system has a clear structure, modular design (especially the resin column), and clearly defined key parameters, facilitating engineering implementation, operation, and maintenance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a waste liquid collection and treatment system for metallographic sample preparation of special metal fuel cores.

[0021] In the diagram: 1—Polishing device; 2—Waste liquid storage tank; 3—Polypropylene filter cotton; 4—Mechanical pump;

[0022] 5—Primary resin column; 6—Secondary resin column; 7—Purified liquid collection / reuse tank; 8—Evaporation and concentration unit; 9—Check valve Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "upper / lower end," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "set / sleeved," "sleeved," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Please see Figure 1 This invention provides a waste liquid collection and treatment system for metallographic sample preparation of special metal fuel cores, including a polishing device 1, a waste liquid storage tank 2, a polypropylene filter cotton 3, a resin unit, and a purified liquid collection and reuse tank 7; the polishing device 1 is connected to the waste liquid storage tank 2 through a pipeline, and the waste liquid storage tank 2 is filled with polypropylene filter cotton 3; the waste liquid storage tank 2 is connected to the resin unit through a pipeline, and the resin unit is connected to the purified liquid collection and reuse tank 7.

[0027] Specifically, a mechanical pump 4 is installed between the waste liquid storage tank 2 and the resin unit. The mechanical pump 4 is used to pump the waste liquid, after preliminary sedimentation and waste residue recovery in the waste liquid storage tank, to the resin purification unit for further treatment at a controllable flow rate (preferably 0.2-0.3 L / min). It adopts a radiation-resistant and corrosion-resistant design to ensure long-term reliable operation.

[0028] Specifically, there is a check valve 9 between the resin unit and the purified liquid collection and reuse tank 7;

[0029] Specifically, the purified liquid collection and reuse tank 7 is connected to the evaporation and concentration device 8; the purified liquid collection and reuse tank 7 is used to collect the waste liquid (purified liquid) after deep purification by the resin unit. It is made of 316L stainless steel, and its capacity is preferably 3-5L. The purified liquid collection and reuse tank 7 is also connected to the polishing device 1. Since the radioactivity level of the collected purified liquid has been significantly reduced, it can be safely used for the preliminary cleaning of core samples and polishing discs, achieving closed-loop reuse of wastewater, significantly reducing the consumption of fresh water and the total amount of radioactive waste liquid requiring final disposal, thus reducing the overall treatment load and disposal costs.

[0030] The evaporation and concentration unit 8 is used to evaporate and concentrate excess purified liquid that cannot be reused or purified liquid accumulated after multiple reuses. The evaporation rate is preferably 0.5L / h to 2.5L / h, and the heating temperature is controlled at 60℃ to 90℃ to reduce aerosol generation and energy consumption, concentrating large quantities of purified liquid into small volumes of high-level radioactive concentrate or solid waste. The significantly reduced volume of the concentrate facilitates subsequent solidification or safe temporary storage, significantly reducing the difficulty and cost of final disposal. The radioactivity level of the distillate is extremely low, and after passing testing, it can be discharged or further reused as appropriate.

[0031] Specifically, the grinding and polishing device 1 is used for grinding and polishing metallographic samples of nuclear fuel cores to obtain a mirror-like observation surface that meets the requirements of high-magnification microscopy. This process uses water and polishing agents and generates waste liquid containing radioactive residue and dissolved nuclides.

[0032] Waste liquid storage tank 2 is used to centrally collect highly radioactive waste liquid generated by the grinding and polishing device, preventing splashing and diffusion and avoiding environmental pollution. It is made of 316L stainless steel, possessing good corrosion resistance and radiation stability. Simultaneously, it serves as a preliminary settling tank for the waste liquid, allowing larger particles to settle naturally, facilitating subsequent separation and recycling. The waste liquid storage capacity is 2-3L. Since a certain amount of large waste residue is generated during the core grinding and polishing sample preparation process, it must be recycled and reused. Therefore, polypropylene filter cotton 3 is added to intercept and recover the solid waste residue mainly containing nuclear materials generated during grinding and polishing.

[0033] Specifically, the resin unit comprises a primary resin column 5 and a secondary resin column 6 connected in series.

[0034] The primary resin column 5 is mainly composed of polystyrene-ethylene-benzene copolymer, nitrogen-containing porous polymer, and acrylic acid-divinylbenzene framework. It is used to remove the main radioactive uranium ion nuclides in waste liquid. It adopts a bottom-in, top-out method, and the flow rate is controlled at 1.5-2 column volumes.

[0035] The secondary resin column 6 is primarily composed of a polystyrene-divinylbenzene framework (containing quaternary ammonium groups) and a styrene-vinylpyridine-divinylbenzene copolymer. It is used for the deep removal of residual radioactive plutonium ions, ensuring a significant reduction in the radioactivity level of the purified solution. It employs a bottom-in, top-out flow method, with the flow rate controlled at 1.5-2 column volumes. The resin achieves a removal rate of over 99% for the target radioactive nuclides.

[0036] The resin columns in the resin unit are designed as modular structures that can be quickly disassembled and replaced, facilitating offline regeneration or replacement after resin saturation. Resin regeneration capability is a key advantage of this system in reducing long-term operating costs and minimizing secondary solid waste. The resin type is selected and customized based on the characteristics of the waste liquid components (such as the main radionuclides, pH, salinity, etc.).

[0037] The following is an example of a specific working process;

[0038] A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores includes the following steps:

[0039] S1: Grinding and polishing device 1 grinds and polishes the core. This process uses water and polishing agent and produces waste liquid containing radioactive waste residue and dissolved nuclides.

[0040] S2: Waste liquid is transported from the grinding and polishing device 1 to a 3L waste liquid storage tank 2 through a stainless steel pipe, and then filtered and recycled through polypropylene filter cotton 3.

[0041] S3: Mechanical pump 4 transports the filtered waste liquid from waste liquid storage tank 2 through pipeline to primary resin column 5 (using polystyrene-ethylenedibenzene copolymer resin) at a controllable flow rate of 0.25 L / min to remove the main radioactive uranium ion nuclides in the waste liquid. The flow rate is controlled at 1.5 column volumes, using a bottom-in, top-out method. Subsequently, the waste liquid passes through secondary resin column 6 (using styrene-vinylpyridine-divinylbenzene copolymer resin) to further remove residual radioactive plutonium ion nuclides. The flow rate is controlled at 1.5 column volumes, using a bottom-in, top-out method.

[0042] S4: The waste liquid after deep purification by the resin unit is transported to the 5L purification liquid collection and reuse tank 7 through a stainless steel pipeline. It can be safely used for the initial cleaning of core samples and polishing discs, thereby realizing the closed-loop reuse of wastewater.

[0043] S5: Excess purified liquid that cannot be reused or purified liquid accumulated after multiple reuses is treated by evaporation and concentration unit 8. The evaporation rate is preferably 1.5 L / h, and the heating temperature is controlled at 80℃, thereby reducing the storage volume of radioactive waste liquid. The units are connected by stainless steel pipes, and check valves are installed between adjacent units to prevent waste liquid backflow.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0045] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0046] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0047] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.

Claims

1. A system for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores, characterized in that: It includes a polishing device (1), a waste liquid storage tank (2), a polypropylene filter cotton (3), a resin unit, and a purified liquid collection and reuse box (7); the polishing device (1) is connected to the waste liquid storage tank (2) through a pipeline, and the waste liquid storage tank (2) is filled with polypropylene filter cotton (3); the waste liquid storage tank (2) is connected to the resin unit through a pipeline, and the resin unit is connected to the purified liquid collection and reuse box (7).

2. The system for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 1, characterized in that: There is a mechanical pump (4) between the waste liquid storage tank (2) and the resin unit.

3. The system for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 2, characterized in that: There is a check valve (9) between the resin unit and the purified liquid collection and reuse box (7).

4. The system for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 3, characterized in that: The purified liquid collection and reuse box (7) is connected to the evaporation and concentration device (8), which is used to evaporate and concentrate excess purified liquid that cannot be reused or purified liquid accumulated after multiple reuses.

5. A waste liquid collection and treatment system for metallographic sample preparation of special metal fuel cores according to claim 4, characterized in that: The resin unit includes a primary resin column (5) and a secondary resin column (6) connected in series. The primary resin column (5) is made of polystyrene-ethylene benzene copolymer, nitrogen-containing porous polymer and acrylic acid-divinylbenzene skeleton; the secondary resin column (6) is made of polystyrene-divinylbenzene skeleton and styrene-vinylpyridine-divinylbenzene copolymer; both the primary resin column (5) and the secondary resin column (6) adopt the bottom-in, top-out method.

6. The system for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 5, characterized in that: The purification liquid collection and reuse box (7) is also connected to the polishing device (1). The purification liquid collected in the purification liquid collection and reuse box (7) is reused for the initial cleaning of the core sample and the polishing disc.

7. A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores, used in the system described in claim 6, characterized in that: Includes the following steps: S1: Grinding and polishing device (1) grinds and polishes the core. This process uses water and polishing agent and produces waste liquid containing radioactive waste residue and dissolved nuclides. S2: Waste liquid is transported from the grinding and polishing device (1) to the waste liquid storage tank (2) through a stainless steel pipe, and then filtered and recycled by polypropylene filter cotton (3). S3: The filtered waste liquid in the waste liquid storage tank (2) is transported through a pipeline to the primary resin column (5) to remove radioactive uranium ion nuclides in the waste liquid; subsequently, the waste liquid passes through the secondary resin column (6) to remove residual radioactive plutonium ion nuclides; S4: The waste liquid purified by the resin unit is transported to the purified liquid collection and reuse tank (7).

8. A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 7, characterized in that: In S3, the mechanical pump (4) transports the filtered waste liquid in the waste liquid storage tank (2) to the primary resin column (5) through a pipeline at a controllable flow rate of 0.25 L / min; both the primary resin column (5) and the secondary resin column (6) adopt the bottom-in, top-out method, and the flow rate is controlled at 1.5 times the column volume.

9. A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 7, characterized in that: In S4, the purified liquid in the purified liquid collection and reuse box (7) is used for core grinding and polishing in S1.

10. A method for collecting and treating waste liquid from metallographic sample preparation of special metal fuel cores according to claim 7, characterized in that: It also includes S5, where excess purified liquid that cannot be reused or purified liquid accumulated after multiple reuses is processed by an evaporation and concentration device (8), with an evaporation rate preferably of 1.5 L / h and a heating temperature controlled at 80°C.

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