Novel molten salt reactor main pump structure with air cavity

Abstract

The invention belongs to the technical field of fluid machinery, and particularly relates to a novel fused salt reactor main pump structure with an air cavity, which comprises an air cavity section and a working section, the air cavity section comprises a first outer shell and an air cavity, the working section comprises a second outer shell and a working cavity, the air cavity is arranged in the first outer shell, and the working cavity is arranged in the second outer shell. A second outer shell is detachably arranged at the bottom of the first outer shell, the air cavity communicates with the working cavity, a rotating rod rotatably penetrates through the top of the first outer shell, and the working end of the rotating rod penetrates through the air cavity and is located in the working cavity; a liquid level measuring component and a space telescopic component are detachably arranged on the inner wall of the air cavity and jointly form a pressure adjusting device, the number of the pressure adjusting devices can be adjusted according to specific conditions, the liquid level measuring component is connected with the space telescopic component, and the liquid level measuring component is used for monitoring the height of molten salt. The space telescopic component expands / contracts according to the height of the fused salt, the space size of the air cavity section is adjusted, accordingly, the air pressure in the air cavity section is adjusted, and finally negative feedback adjustment on the height of the liquid level of the fused salt is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid machinery, and in particular relates to a novel main pump structure of a molten salt reactor with an air cavity. Background Art

[0002] The main pump for a molten salt reactor (MSR) is the core power unit of the primary circuit of a loop-type molten salt reactor (MSR). Molten salt serves as the heat exchange medium, and the main pump's primary function is to maintain the circulation of the molten salt within the reactor. Due to the high temperature of the molten salt, the main pump must possess excellent high-temperature tolerance and sealing properties to ensure the safe circulation of the molten salt within the reactor. Conventional PWR primary circuit main pumps utilize a shielded main pump structure. The primary circuit primarily undergoes a gas-liquid phase transition, with no solid-liquid phase transition. Within a MSR system, the molten salt transitions from liquid to solid as it cools. The liquid-to-solid phase transition caused by the high-temperature molten salt filling the shielded pump motor poses a risk of motor failure and operational failure due to the excessively high temperature of the molten salt. Conventional mechanical seals prevent molten salt from entering the motor cavity, protecting key motor components from the effects of liquid-solid phase transition and the high temperature of the molten salt. However, this solution presents a risk of high and low temperatures converging at the mechanical seal, causing the liquid, high-temperature molten salt to crystallize and solidify, damaging the mechanical seal surface, leading to seal failure and leakage of highly radioactive materials. The use of mechanical shaft seal pumps in the primary circuit system of molten salt reactors creates an extremely high risk of molten salt leakage.

[0003] The key to the structure of a loop-type molten salt reactor's main pump is how to achieve a molten salt seal. Mechanical seals, due to crystallization and solidification of the molten salt, pose a high risk of leaking radioactive materials. Achieving a primary loop molten salt seal is a key issue in the sealing structure of a molten salt reactor's main pump. Summary of the Invention

[0004] The purpose of the present invention is to provide a novel main pump structure of a molten salt reactor with an air cavity.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A novel main pump structure for a molten salt reactor with an air cavity comprises an air cavity section and a working section, wherein the air cavity section comprises a first outer shell and an air cavity, and the working section comprises a second outer shell and a working cavity, wherein the air cavity is provided in the first outer shell, and the working cavity is provided in the second outer shell, the second outer shell is detachably provided at the bottom of the first outer shell, the air cavity is connected to the working cavity, a rotating rod is rotatably provided through the top of the first outer shell, the working end of the rotating rod passes through the air cavity and is located in the working cavity; a liquid level measuring component and a space expansion component are detachably provided on the inner wall of the air cavity, the liquid level measuring component is connected to the space expansion component, the liquid level measuring component is used to monitor the height of molten salt, and the space expansion component expands / contracts according to the height of molten salt.

[0007] Furthermore, the liquid level measuring component includes a monitoring structure and a first pushing structure, the space telescopic component includes a second pushing structure and a telescopic structure, the first pushing structure is detachably provided on the inner wall of the air cavity, the monitoring structure is slidably provided on the bottom of the first pushing structure, the second pushing structure is detachably provided on the inner wall of the air cavity, the telescopic structure is fixedly provided on the bottom of the second pushing structure, and the top of the first pushing structure and the top of the second pushing structure are connected through a connecting pipe.

[0008] Furthermore, the monitoring structure includes a float, a limit block, a spring, a fixed block and a push rod. The fixed block is fixedly provided on the inner wall of the air cavity, the push rod is slidably provided on the fixed block, the push rod is located at the bottom part of the fixed block and the limit block is fixedly provided, the push rod is sleeved with the spring, the spring is located between the fixed block and the limit block, the float is provided at the bottom of the push rod, and the top of the push rod is fixedly connected to the first pushing structure.

[0009] Furthermore, the first pushing structure includes a first sleeve and a first piston, the first piston is slidably provided in the first sleeve, the pushing rod is fixedly provided at the bottom of the first piston, the top of the first sleeve is connected to the connecting pipe, and the first sleeve is detachably provided on the inner wall of the air cavity.

[0010] Furthermore, the telescopic structure includes a bottom plate, a bellows, a limiting rod, a top plate, a slide plate, an arc-shaped support plate and a connecting rod; the second pushing structure includes a second sleeve and a second piston;

[0011] The second sleeve is detachably provided on the inner side wall of the air cavity, the top of the second sleeve is connected to the communicating pipe, the second piston is slidably provided in the second sleeve, and the bottom of the second sleeve is symmetrically provided with two arc-shaped support plates around the axis, the bottom of the arc-shaped support plate is fixedly provided with the top plate, the bottom of the top plate is fixedly provided with the bellows, the bottom of the bellows is fixedly provided with the bottom plate, the slide plate is slidably provided between the two arc-shaped support plates, the connecting rod is fixedly provided between the slide plate and the second piston, and a plurality of limit rods are provided on the circumference of the bottom of the slide plate, the limit rods pass through the top plate and are fixedly connected to the bottom plate, and the limit rods are slidably connected to the top plate.

[0012] Furthermore, the working end of the rotating rod is provided with a guide vane for guiding flow.

[0013] Furthermore, a molten salt inlet is provided at the bottom of the second outer shell, and a molten salt outlet is provided on the side wall of the second outer shell. The molten salt inlet and the molten salt outlet are connected to the working chamber.

[0014] Furthermore, an air inlet is provided on the side wall of the first outer shell, and the air inlet is connected to the air cavity.

[0015] The present invention has the following beneficial effects: by providing an air cavity section and injecting inert gas into the air cavity section, a stable gas barrier is generated to prevent the molten salt liquid level from being too high and directly contacting the sealing section to damage the device. However, the molten salt pressure in the air cavity will change with the working conditions of the pump. If it is not controlled, there may be a problem of insufficient dry gas pressure and molten salt flowing back into the gas injection system, or excessive pressure gas entering the pump section and causing cavitation, causing the pump to vibrate and make noise, and even causing corrosion and damage to the impeller and pump, shortening the life of the pump. Therefore, a liquid level measuring component and a space expansion component are provided. The liquid level measuring component can monitor the height of the liquid level, and the space expansion component can expand and contract in real time according to the change in the liquid level height, thereby changing the relative space size of the air cavity section, thereby changing the internal air pressure, and ultimately keeping the liquid level at a relatively stable height, preventing gas from entering the pump section or molten salt from entering the sealing section. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 This is the exploded view of the second propulsion structure. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0019] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] like Figure 1-2As shown, a new type of main pump structure of a molten salt reactor with an air cavity includes an air cavity section and a working section. The air cavity section includes a first outer shell 2 and an air cavity 202, and the working section includes a second outer shell 3 and a working cavity 303. The air cavity 202 is provided in the first outer shell 2, and the working cavity 303 is provided in the second outer shell 3. The bottom of the first outer shell 2 is detachably provided with a second outer shell 3, the air cavity 202 is connected to the working cavity 303, and the top of the first outer shell 2 is rotatably penetrated by a rotating rod 1, the working end of the rotating rod 1 passes through the air cavity 202 and is located in the working cavity 303; a liquid level measuring component 5 and a space telescopic component 6 are detachably provided on the inner wall of the air cavity 202, and the liquid level measuring component 5 and the space telescopic component 6 together constitute a pressure regulating device. The number of pressure regulating devices can be adjusted according to specific circumstances. The liquid level measuring component 5 is connected to the space telescopic component 6. The liquid level measuring component 5 is used to monitor the height of the molten salt, and the space telescopic component 6 expands / contracts according to the height of the molten salt. The monitoring structure of the liquid level measuring component 5 monitors the height of the molten salt in the pump body and then pulls the first piston 507 upward / downward to push the hydraulic oil in the first sleeve 506. The power is transmitted to the second piston 608 through the hydraulic oil, thereby causing the bellows 602 to expand / contract, thereby adjusting the size of the air cavity section space, thereby adjusting the gas pressure in the air cavity section, and finally achieving negative feedback regulation of the molten salt liquid level.

[0021] like Figure 1 As shown, the liquid level measuring component 5 includes a monitoring structure and a first pushing structure, the space telescopic component 6 includes a second pushing structure and a telescopic structure, the first pushing structure is detachably provided on the inner wall of the air cavity 202, and a monitoring structure is slidably provided at the bottom of the first pushing structure, the second pushing structure is detachably provided on the inner wall of the air cavity 202, and a telescopic structure is fixedly provided at the bottom of the second pushing structure, and the top of the first pushing structure and the top of the second pushing structure are connected through a connecting pipe 509.

[0022] Furthermore, the monitoring structure includes a float 501, a limit block 502, a spring 503, a fixed block 504, and a push rod 505. The fixed block 504 is fixed on the inner wall of the air cavity 202. The push rod 505 is slidably mounted on the fixed block 504. The push rod 505 is located at the bottom of the fixed block 504 and fixed with the limit block 502. The push rod 505 is sleeved with a spring 503, which is located between the fixed block 504 and the limit block 502. The float 501 is mounted at the bottom of the push rod 505. The top of the push rod 505 is fixedly connected to the first push structure. The first push structure includes a first sleeve 506 and a first piston 507. The first piston 507 is slidably mounted in the first sleeve 506. The push rod 505 is fixed at the bottom of the first piston 507. The first sleeve 506 is connected to a connecting pipe 509. The first sleeve 506 is detachably mounted on the inner wall of the third outer shell 12. The float 501 is a hollow iron structure, which ensures that it will not liquefy in the high-temperature molten salt while providing sufficient buoyancy. When the molten salt liquid level rises, the float 501 drives the push rod 505 to move upward, thereby pushing the piston upward. The hydraulic oil in the first sleeve 506 flows into the second sleeve 609 through the connecting pipe 509. Conversely, when the molten salt liquid level drops, the push rod 505 drives the first piston 507 to move downward under the action of the spring 503, so that the hydraulic oil in the second sleeve 609 enters the first sleeve 506. The spring 503 is made of a high-temperature alloy (such as Inconel or Hastelloy). The hydraulic oil is made of a material with a high ignition point and boiling point (such as silicon-based hydraulic oil). At the same time, the first sleeve 506, the second sleeve 609 and the connecting pipe 509 can be covered with a heat-insulating material.

[0023] It should be emphasized that the telescopic structure includes a bottom plate 601, a bellows 602, a limit rod 603, a top plate 604, a slide plate 605, an arc-shaped support plate 606 and a connecting rod 607; the second pushing structure includes a second sleeve 609 and a second piston 608; a second sleeve 609 is detachably provided on the inner wall of the air cavity 202, the top of the second sleeve 609 is connected to the connecting pipe 509, a second piston 608 is slidably provided in the second sleeve 609, and two arc-shaped pistons are symmetrically provided on the bottom of the second sleeve 609 around the axis. Support plate 606, a top plate 604 is fixed at the bottom of the arc-shaped support plate 606, a bellows 602 is fixed at the bottom of the top plate 604, a bottom plate 601 is fixed at the bottom of the bellows 602, a slide plate 605 is slidably provided between the two arc-shaped support plates 606, a connecting rod 607 is fixed between the slide plate 605 and the second piston 608, and a plurality of limiting rods 603 are provided on the circumference of the bottom of the slide plate 605. The shape and distribution of the arc-shaped support plate 606, the shape of the slide plate 605 and the connection between the limiting rod 603 are as follows: Figure 2As shown, the limiting rod 603 runs through the top plate 604 and is fixedly connected to the bottom plate 601, and the limiting rod 603 is slidably connected to the top plate 604. When the molten salt liquid level rises, the hydraulic oil in the second sleeve 609 increases, pushing the second piston 608 and the limiting rod 603 downward, and then pushing the bottom plate 601 to move downward, thereby stretching the bellows 602 internal space so that the air cavity 202 internal space (the relative space of gas storage) is relatively reduced so that the internal gas pressure increases and pushes the molten salt liquid level downward in the opposite direction. On the contrary, when the molten salt liquid level drops, the hydraulic oil in the second sleeve 609 decreases, and the second piston 608 moves upward to pull the limiting rod 603 and the bottom plate 601 upward, thereby compressing the bellows 602 internal space, increasing the relative space of the air cavity 202, reducing the internal gas pressure of the air cavity 202, reducing the pressure on the molten salt liquid level, thereby making the molten salt liquid level have a relatively upward trend. In addition, the rise / fall of the molten salt liquid level itself will also lead to an increase / decrease in the gas pressure inside the air cavity 202, thereby achieving relative negative feedback regulation. The bellows 602 can be made of a high-temperature resistant alloy such as Inconel 625 or Hastelloy X. In addition, the bellows 602 is only one embodiment and can also be two closed chambers that can slide relative to each other. It only needs to be able to achieve relative expansion / contraction of the internal closed space under the push of the limit rod 603 so that the relative space of the air cavity 202 is reduced / increased. In addition, it should be noted that in order to ensure that the buoyancy provided by the float 501 can push the first piston 507 and the second piston 608, the cross-sectional area of the first piston 507 should be smaller than the cross-sectional area of the second piston 608. The thrust ratio of the second piston 608 to the first piston 507 is linearly related to the ratio of the cross-sectional areas of the two. The actual setting depends on the specific situation. The height of the molten salt liquid level is mainly related to the injection pressure, inlet and outlet flow rates and other working conditions. The relative space size of the air cavity section is also related to the two. The gas in the air cavity section will perform a negative feedback regulation on the relative change of the space. The pressure regulating device is set to amplify the intensity of this negative feedback regulation (achieved by increasing the degree of internal air pressure change through the relative size of the dynamic step air cavity section), so that the molten salt liquid level can tend to be stable and stabilize between the high liquid level and the low liquid level.

[0024] In addition, the working end of the rotating rod 1 is equipped with a guide vane 3 for flow diversion. A molten salt inlet 301 is provided at the bottom of the second outer shell 3, and a molten salt outlet 302 is provided on the side wall of the second outer shell 3. The molten salt inlet 301 and the molten salt outlet 302 are connected to the working chamber 303. An air inlet 201 is provided on the side wall of the first outer shell 2, connecting to the air chamber 202. The air inlet 201 is connected to an external gas injection component. During operation, an appropriate amount of inert gas is injected into the air chamber to maintain the air pressure balance within the air chamber and keep the molten salt liquid level at an appropriate height. The air inlet 201 is then closed.

[0025] It should be noted that another shell is provided on the top of the first outer shell 2, and a dry gas sealing device and a mechanical sealing device are provided inside the shell. The dry gas sealing device and the mechanical sealing device are sleeved on the rotating rod 1. The dry gas sealing device and the mechanical sealing device are both existing technologies. At the same time, because they are not the improvement points of the present invention, they will not be described in detail.

[0026] Working principle: molten salt enters the working chamber 303 through the molten salt inlet 301, and diffuses into the air chamber 202 from the working chamber 303. After the flow is stabilized by the guide vane 4 in the working chamber 303, it flows out from the molten salt outlet 302 to the external circulation pipeline. When the molten salt enters the working section, the injection pressure and flow rate will change to a certain extent, and the molten salt liquid level will also change. When the molten salt liquid level rises, it will drive the push rod 505 to move upward through the float 501 and then push the piston to move upward. The hydraulic oil in the first sleeve 506 flows into the second sleeve 609 through the connecting pipe 509. The hydraulic oil in the second sleeve 609 increases, pushing the second piston 608 and the limit rod 603 downward, and then pushing the bottom plate 601 to move downward, thereby stretching the internal space of the bellows 602 so that the internal space of the air chamber 202 is relatively reduced, thereby increasing the internal gas pressure and pushing the molten salt liquid level down in the opposite direction. When the molten salt level drops, the push rod 505 drives the first piston 507 to move downward under the action of the spring 503, so that the hydraulic oil in the second sleeve 609 enters the first sleeve 506. When the molten salt level drops, the hydraulic oil in the second sleeve 609 decreases, and the second piston 608 moves upward to pull the limit rod 603 and the bottom plate 601 upward, thereby compressing the internal space of the bellows 602, increasing the relative space of the air cavity 202, reducing the gas pressure in the air cavity 202, reducing the pressure on the molten salt liquid surface, and causing the molten salt liquid surface to have a relatively upward trend.

[0027] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various deformations, modifications, and substitutions made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A new type of main pump structure for molten salt reactor with air cavity, characterized by: The invention comprises an air cavity section and a working section, wherein the air cavity section comprises a first outer shell (2) and an air cavity (202), and the working section comprises a second outer shell (3) and a working cavity (303), wherein the air cavity (202) is provided in the first outer shell (2), and the working cavity (303) is provided in the second outer shell (3), the bottom of the first outer shell (2) is detachably provided with the second outer shell (3), the air cavity (202) is connected to the working cavity (303), the top of the first outer shell (2) is rotatably provided with a rotating rod (1), the working end of the rotating rod (1) passes through the air cavity (202) and is located in the working cavity (303); a liquid level measuring component (5) and a space expansion component (6) are detachably provided on the inner wall of the air cavity (202), the liquid level measuring component (5) is connected to the space expansion component (6), the liquid level measuring component (5) is used to monitor the height of the molten salt, and the space expansion component (6) expands / contracts according to the height of the molten salt.

2. The novel main pump structure of a molten salt reactor with an air cavity according to claim 1 is characterized in that: The liquid level measuring component (5) includes a monitoring structure and a first pushing structure, and the space telescopic component (6) includes a second pushing structure and a telescopic structure. The first pushing structure is detachably provided on the inner wall of the air cavity (202), and the monitoring structure is slidably provided on the bottom of the first pushing structure. The second pushing structure is detachably provided on the inner wall of the air cavity (202), and the telescopic structure is fixedly provided on the bottom of the second pushing structure. The top of the first pushing structure and the top of the second pushing structure are connected through a connecting pipe (509).

3. The novel main pump structure of a molten salt reactor with an air cavity according to claim 2 is characterized in that: The monitoring structure comprises a float (501), a limit block (502), a spring (503), a fixed block (504) and a push rod (505); the fixed block (504) is fixedly provided on the inner wall of the air cavity (202); the push rod (505) is slidably provided on the fixed block (504); the push rod (505) is located at the bottom part of the fixed block (504) and is fixedly provided with the limit block (502); the push rod (505) is sleeved with the spring (503); the spring (503) is located between the fixed block (504) and the limit block (502); the float (501) is provided at the bottom of the push rod (505); and the top of the push rod (505) is fixedly connected to the first pushing structure.

4. The novel main pump structure of a molten salt reactor with an air cavity according to claim 3 is characterized by: The first pushing structure includes a first sleeve (506) and a first piston (507), the first piston (507) is slidably provided in the first sleeve (506), the pushing rod (505) is fixedly provided at the bottom of the first piston (507), the top of the first sleeve (506) is connected to the connecting pipe (509), and the first sleeve (506) is detachably provided on the inner wall of the air cavity (202).

5. The novel main pump structure of a molten salt reactor with an air cavity according to claim 2 is characterized in that: The telescopic structure includes a bottom plate (601), a bellows (602), a limiting rod (603), a top plate (604), a slide plate (605), an arc-shaped support plate (606) and a connecting rod (607); the second pushing structure includes a second sleeve (609) and a second piston (608); The second sleeve (609) is detachably provided on the inner wall of the air cavity (202), the top of the second sleeve (609) is connected to the connecting pipe (509), the second piston (608) is slidably provided in the second sleeve (609), the bottom of the second sleeve (609) is symmetrically provided with two arc-shaped support plates (606) around the axis, the bottom of the arc-shaped support plate (606) is fixedly provided with the top plate (604), the bottom of the top plate (604) is fixedly provided with the bellows (602), and the bellows The bottom of (602) is fixedly provided with the bottom plate (601), the slide plate (605) is slidably provided between the two arc-shaped support plates (606), the connecting rod (607) is fixedly provided between the slide plate (605) and the second piston (608), and a plurality of limiting rods (603) are provided on the circumference of the bottom of the slide plate (605), the limiting rods (603) pass through the top plate (604) and are fixedly connected to the bottom plate (601), and the limiting rods (603) are slidably connected to the top plate (604).

6. The novel main pump structure of a molten salt reactor with an air cavity according to claim 1 is characterized in that: The working end of the rotating rod (1) is provided with a guide vane (3) for guiding flow.

7. The novel main pump structure of a molten salt reactor with an air cavity according to claim 1 is characterized in that: A molten salt inlet (301) is provided at the bottom of the second outer shell (3), and a molten salt outlet (302) is provided on the side wall of the second outer shell (3); the molten salt inlet (301) and the molten salt outlet (302) are connected to the working chamber (303).

8. The novel main pump structure of a molten salt reactor with an air cavity according to claim 1 is characterized by: An air inlet (201) is provided on the side wall of the first outer shell (2), and the air inlet (201) is connected to the air cavity (202).

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