Impurity particle filtering device for lead-bismuth loop

Abstract

The invention provides an impurity particle filtering device for a lead-bismuth loop, and belongs to the technical field of impurity filtering, the impurity particle filtering device comprises a barrel, a material conveying pipe and a conical shell, the material conveying pipe extends into the barrel and is communicated with the barrel, the conical shell is fixedly mounted at the bottom of the barrel, the barrel is communicated with the conical shell, and the conical shell is fixedly mounted at the bottom of the barrel. The conical shell is in a funnel shape, a flow guide plate is fixedly installed at the end, stretching into the barrel, of the conveying pipe, the flow guide plate inclines towards the end away from the conveying pipe, and the inner diameter of the barrel is larger than the inner diameter of the conveying pipe. Impurity particles and liquid lead-bismuth eutectic are separated and filtered on the basis of buoyancy applied to the impurity particles caused by density difference between the impurity particles and the liquid lead-bismuth eutectic, the device can run in a lead-bismuth circulation loop for a long time, and the impurity particles can be effectively filtered and stored in a barrel of a pressure container in real time; and the defects of high flow resistance, easiness in damage, easiness in blockage and the like caused by the existing filter are overcome.

Description

Technical Field

[0001] This invention belongs to the field of impurity filtration technology, specifically an impurity particle filtration device for lead-bismuth circuits. Background Technology

[0002] Lead-bismuth fast reactors are one of the most promising reactor types in the fourth-generation reactor system, possessing advantages such as compact reactor design, high safety, high thermal efficiency, and strong adaptability. They are well-suited for platforms with specific needs for small size, high power, and high flexibility. As a novel coolant material, lead-bismuth eutectic in lead-bismuth fast reactors combines various advantages in nuclear physics, materials science, and thermodynamics, enabling safe and efficient operation. Therefore, it has been selected as the spallation target and primary coolant for lead-bismuth fast reactors. However, the corrosive effect of liquid lead-bismuth eutectic inevitably leads to the appearance of impurity particles in the circuit. The main components of these impurity particles are metal oxides, such as lead oxide particles and iron oxide particles. Due to their high melting point, these impurity particles cannot melt in the lead-bismuth circulation loop and can only exist in particulate form in the liquid lead-bismuth eutectic fluid. When deposited on the tube wall, they form a sticky layer, increasing the heat transfer resistance of the tube wall, and may even lead to excessive deposition and blockage of the pipes. Meanwhile, these impurity particles, along with the flowing liquid lead-bismuth eutectic, violently impact the pipe wall at pipe bends, causing severe damage to the pipe structure and resulting in serious erosion, which greatly affects the economics and safety of the reactor.

[0003] Currently, the impurity particle filtration devices commonly used in lead-bismuth fast reactors both domestically and internationally for lead-bismuth circuits generally employ woven alumina fibers, glass fibers, woven metal mesh, or sintered metal filters. For example, the Liliputter II lead-bismuth circulation circuit of the MYRRHA project at the Belgian Nuclear Research Centre uses 50-micron pore size 316L stainless steel sintered powder filter discs to filter out micron-sized impurity particles in the flowing lead-bismuth eutectic.

[0004] However, while these filters effectively remove impurities from the lead-bismuth circulation loop, their micron-sized filter elements increase the flow resistance of the liquid lead-bismuth eutectic, significantly increasing the power required for its circulation. Furthermore, these filters typically use relatively lead-bismuth-resistant steels such as austenitic stainless steel 316L; however, these materials suffer severe erosion and corrosion during prolonged flow of the lead-bismuth medium, gradually failing to effectively filter particulate matter. They may even oxidize and corrode under the influence of the lead-bismuth medium, producing impurities or breaking down, causing significant damage to the lead-bismuth circulation loop. Even more seriously, existing research indicates that a large number of impurities and corrosion products adhere to these filters, ultimately causing loop blockage. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide an impurity particle filtration device for lead-bismuth circuits.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an impurity particle filtering device for a lead-bismuth circuit, comprising a cylinder, a feed pipe, and a conical shell, wherein the feed pipe extends into the cylinder and is connected to the cylinder, the conical shell is fixedly installed at the bottom of the cylinder and is connected to the cylinder, the conical shell is funnel-shaped, a guide plate is fixedly installed at one end of the feed pipe extending into the cylinder, the guide plate is inclined toward the end away from the feed pipe, and the inner diameter of the cylinder is larger than the inner diameter of the feed pipe.

[0007] As a further improvement: a cap is fixedly installed at the top of the cylinder, and the cap is elliptical in shape.

[0008] As a further improvement: a discharge pipe is fixedly installed at the end of the conical shell away from the cylinder, and the discharge pipe is connected to the conical shell.

[0009] As a further improvement: a number of fixing rods are fixedly installed at one end of the conveying pipe that extends into the cylinder, and a guide plate is fixedly installed at the end of the fixing rod away from the conveying pipe.

[0010] As a further improvement, it also includes a temperature detection element and a heating element, which are installed on the inner wall of the cylinder.

[0011] Compared with existing technologies, the beneficial effects of this invention are: based on the density difference between impurity particles and liquid lead-bismuth eutectic, the buoyancy applied to the impurity particles separates and filters the impurity particles from the liquid lead-bismuth eutectic. Compared with filters commonly used in lead-bismuth circulation loops, this invention's device can operate in the lead-bismuth circulation loop for extended periods, effectively filtering impurity particles and storing them in the pressure vessel cylinder in real time. It also avoids the defects of current filters, such as high flow resistance, easy breakage, and easy clogging. Ultimately, it prevents impurity particles from reducing the heat exchange efficiency of the circulation loop, causing blockage, and impacting and bending the pipe walls, thus preventing structural damage. Therefore, this device has significant practical implications for the economy and safety of lead-bismuth fast reactors. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of an impurity particle filtration device for a lead-bismuth circuit.

[0013] In the diagram: 1. End cap; 2. Cylinder; 3. Inner cavity; 4. Conical shell; 5. Baffle plate; 6. Feed pipe; 7. Temperature detection element; 8. Discharge pipe. Detailed Implementation

[0014] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0015] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0016] Please see Figure 1 In one embodiment, an impurity particle filtering device for a lead-bismuth circuit is characterized by comprising a cylindrical body 2, a feed pipe 6, and a conical shell 4. The feed pipe 6 extends into the cylindrical body 2 and is in communication with the cylindrical body 2. The conical shell 4 is fixedly installed at the bottom of the cylindrical body 2 and is in communication with the cylindrical body 2. The conical shell 4 is funnel-shaped. A guide plate 5 is fixedly installed at one end of the feed pipe 6 that extends into the cylindrical body 2. The guide plate 5 is inclined toward the end away from the feed pipe 6. The inner diameter of the cylindrical body 2 is larger than the inner diameter of the feed pipe 6.

[0017] The top end of the cylinder 2 is fixedly installed with a cap 1, which is elliptical in shape.

[0018] In this embodiment, the lead-bismuth eutectic alloy flows into the cylinder 2 through the feed pipe 6. Under the action of the guide plate 5 at the inlet of the feed pipe 6, the lead-bismuth eutectic alloy flows into the inner cavity 3 of the cylinder 2 through the feed pipe 6. Under the action of the guide plate 5 and the inner cavity 3 with a large inner diameter, the overall flow rate of the fluid remains unchanged, but the flow velocity is significantly reduced. Furthermore, the inflowing lead-bismuth eutectic impacts the surface of the guide plate 5, and the impact on the guide plate 5 causes the backflowing liquid lead-bismuth eutectic and the subsequent liquid lead-bismuth eutectic alloy flowing to the guide plate 5 to form a high-pressure, low-velocity region at the guide plate 5. This causes the liquid lead-bismuth eutectic carrying impurity particles to flow towards the outlet of the elliptical head 1, resulting in a large accumulation of impurity particles at the top of the filter device. Due to the action of the guide plate 5 and the large inner diameter cavity 3, the flow velocity of the liquid lead-bismuth eutectic is low, that is, the liquid-solid coupling force (dragging force) between the liquid lead-bismuth eutectic and the impurity particles is small. This makes buoyancy and gravity the main forces acting on the impurity particles. Since the density of the liquid lead-bismuth alloy is greater than the density of the impurity particles, the buoyancy force on the impurity particles is greater than the gravity force, causing the impurity particles to slowly float up in the filtration device and accumulate at the top elliptical end cap 1, thus achieving the purpose of filtering out the impurity particles from the lead-bismuth circulation loop.

[0019] Please see Figure 1 In one embodiment, a discharge pipe 8 is fixedly installed at one end of the conical shell 4 away from the cylindrical body 2, and the discharge pipe 8 is connected to the conical shell 4.

[0020] In this embodiment,

[0021] Please see Figure 1 In one embodiment, a plurality of fixing rods are fixedly installed at one end of the conveying pipe 6 that extends into the cylinder 2, and a guide plate 5 is fixedly installed at the end of the fixing rod that is away from the conveying pipe 6.

[0022] In this embodiment, the guide plate 5 is used to reduce the flow velocity of the bismuth eutectic and guide impurity particles to the top of the filter device. The guide plate 5 is a stainless steel metal plate located in the inner cavity 3, connected to the feed pipe 6 at a certain angle to the vertical direction. The fixing rod can be made of solid steel pipe, and the guide plate 5 is welded to the feed pipe 6 by three solid steel pipes. Liquid lead-bismuth eutectic flows into the feed pipe 6 and impacts the guide plate 5. Under the guiding action of the guide plate 5, the liquid lead-bismuth eutectic flows into the inner cavity 3 of the filter device through the connection between the guide plate 5 and the feed pipe 6.

[0023] Please see Figure 1 In one embodiment, the device further includes a temperature detection element 7 and a heating element, which are mounted on the inner wall of the cylinder 2.

[0024] In this embodiment, the temperature sensing element 7 can be a thermocouple, and the heating element can be an electric heating tape. The temperature is controlled by wrapping the electric heating tape and insulation cotton around the outside and by monitoring the thermocouple reading in real time.

[0025] Thermocouples are used to detect the temperature of liquid lead-bismuth eutectic inside the filter device. In the circulation loop, the liquid lead-bismuth alloy can be prevented from solidifying and causing blockage due to low temperature by using electric heating tape and insulation cotton wrapped around the outside.

[0026] Based on current domestic and international research on lead-bismuth recycling loops, the main components of impurity particles are the oxidation and corrosion products of structural steel, namely, iron(III) oxide and lead oxide. The principle and products of oxidation and oxide layer reduction separation of structural materials in the lead-bismuth recycling loop are shown in the following formula:

[0027]

[0028]

[0029] Liquid lead-bismuth eutectic has a relatively high density (approximately ten times that of water), greater than most particulate matter. The density of iron(III) oxide and lead oxide is less than that of liquid lead-bismuth eutectic. According to the buoyancy formula, iron(III) oxide and lead oxide experience a constant upward buoyancy force in liquid lead-bismuth eutectic.

[0030]

[0031] Where F Gρ is the resultant force of gravity and buoyancy acting on a unit mass of particle in the vertical direction, g is the acceleration due to gravity, and ρ is the acceleration due to gravity. LBE ρ is the eutectic density of liquid lead-bismuth. p This represents the density of impurity particles.

[0032] The force balance equation for particles in the flow field is:

[0033]

[0034] In the formula u p F represents the velocity of discrete phase particles, u represents the flow velocity of the liquid lead-bismuth eutectic; D (uu p The drag force F is the force exerted on a unit mass of particles along the relative flow direction. In the filtration device, due to the action of the guide plate 5 and the large-diameter inner cavity 3, the flow velocity of the liquid lead-bismuth eutectic is relatively low, resulting in a low relative flow velocity between the liquid lead-bismuth eutectic and the impurity particles, i.e., the drag force F. D (uu p The buoyancy is relatively low at this time. G The main force acts on the impurity particles, causing them to move slowly upward in the filtration device and accumulate at the top elliptical end cap 1, thus achieving the purpose of filtering out the impurity particles from the lead-bismuth circulation loop.

[0035] Compared to current filtration devices commonly used in lead-bismuth circulation loops, this invention utilizes the density difference between impurity particles and the liquid lead-bismuth medium, rather than relying on the pore size of current filters to prevent the passage of micron-sized particles. This eliminates the drawbacks of filters with micron-sized pores, such as high flow resistance, susceptibility to damage, and easy clogging. As a result, this invention not only effectively separates impurity particles from the liquid lead-bismuth eutectic but also boasts long-term operational reliability, the ability to filter and store large quantities of particles, and convenient replacement, making it highly practical for engineering applications.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A particle filtration device for lead-bismuth circuits, characterized in that, The device includes a cylinder, a conveying pipe, and a conical shell. The conveying pipe extends into the cylinder and is connected to the cylinder. A conical shell is fixedly installed at the bottom of the cylinder and is connected to the cylinder. The conical shell is funnel-shaped. A guide plate is fixedly installed at one end of the conveying pipe that extends into the cylinder. The guide plate is inclined toward the end away from the conveying pipe. The inner diameter of the cylinder is larger than the inner diameter of the conveying pipe.

2. The impurity particle filtering device for a lead-bismuth circuit according to claim 1, characterized in that, A cap is fixedly installed at the top of the cylinder, and the cap is elliptical in shape.

3. The impurity particle filtering device for a lead-bismuth circuit according to claim 1, characterized in that, A discharge pipe is fixedly installed at one end of the conical shell away from the cylinder, and the discharge pipe is connected to the conical shell.

4. The impurity particle filtering device for a lead-bismuth circuit according to claim 1, characterized in that, A number of fixing rods are fixedly installed at one end of the conveying pipe that extends into the cylinder, and a guide plate is fixedly installed at the end of the fixing rod that is away from the conveying pipe.

5. The impurity particle filtering device for a lead-bismuth circuit according to claim 1, characterized in that, It also includes a temperature detection element and a heating element, which are installed on the inner wall of the cylinder.

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