WO2021248389A1

WO2021248389A1 - Self-rotating shielding device and use method therefor

Info

Publication number: WO2021248389A1
Application number: PCT/CN2020/095472
Authority: WO
Inventors: 周国丰; 郑传栋; 刘刚; 何之; 丁慧民; 唐叔建; 吴玉; 刘治; 张梦金
Original assignee: 中广核研究院有限公司; 中国广核集团有限公司; 中国广核电力股份有限公司
Priority date: 2020-06-10
Filing date: 2020-06-10
Publication date: 2021-12-16

Abstract

A self-rotating shielding device and a use method therefor. The self-rotating shielding device comprises a shielding main body (10), a shielding ball (20), and at least one group of linking components (30). The shielding main body (10) is provided with a fuel channel (100) penetrating through two opposite ends thereof and used for allowing a fuel component to pass through; the shielding ball (20) is rotatably provided in the fuel channel (100), and is provided with a ball channel (200) penetrating through two opposite ends thereof; the linking components (30) pass through one end of the shielding main body (10) and are connected to the shielding ball (20); the linking components (30) have one end exposed on one end of the shielding main body (10), and drive by action the shielding ball (20) to rotate back and forth between a first position and a second position under the action of the external force to open or close the fuel channel (100). The self-rotating shielding device is used for ray irradiation shielding in the loading and unloading process of the fuel component, does not require the staff to operate to open or close the fuel channel (100), reduces the risk that the staff is exposed to radiation, shortens the operation procedure, and improves the efficiency.

Description

Self-rotating shielding device and method of use

Technical field

The invention relates to the technical field of reactor nuclear fuel loading and unloading, in particular to a self-rotating shielding device and a use method thereof.

Background technique

At present, during the loading and unloading process of the core fuel assembly of the small-scale marine reactor, cooling water is used to shield the core radiation or rely on the control of the operator to realize the partial opening of the core radiation shield. The current two methods have the following shortcomings:

In the use of cooling water to shield the core radiation, the fuel assembly operation must be performed underwater, and the shielding water layer must be at least 3m deep, which is not suitable for radiation shielding in narrow spaces, and is not suitable for water-free refueling conditions.

... Relying on the control of the operator to realize the partial opening of the core radiation shielding body requires personnel to operate, resulting in a more complicated work flow; there is a risk of misoperation, which leads to the shielding being opened by mistake; the work flow connection cannot be seamlessly connected, and the shielding is opened in advance The core ray is in an unshielded state. Delaying opening the shielding body will increase the time of the entire operation process.

technical problem

The technical problem to be solved by the present invention is to provide a self-rotating shielding device for loading and unloading fuel assemblies and a method of use thereof in view of the above-mentioned defects in the prior art.

Technical solutions

The technical solution adopted by the present invention to solve its technical problems is to provide a self-rotating shielding device for loading and unloading fuel assemblies, the self-rotating shielding device including a shielding body, a shielding sphere, and at least one set of linkage components;

The shielding body is provided with fuel passages penetrating opposite ends of the shield body and used for the passage of fuel assemblies; the shielding sphere is rotatably arranged in the fuel passage, and the shielding sphere is provided with spheres penetrating the opposite ends of the shielding sphere. aisle;

The interlocking component penetrates into one end of the shielding body and is connected to the shielding sphere; one end of the interlocking component is exposed on one end of the shielding body, and under the action of external force, the shielding sphere is actuated to drive the shielding sphere to a first Rotate back and forth between position and a second position;

When the shielding sphere is in the first position, the sphere passage and the fuel passage are connected in parallel to open the fuel passage;

When the shielding sphere is in the second position, the sphere passage is staggered from the fuel passage, and the fuel passage is closed.

Preferably, the linkage assembly includes a rotating gear, a trigger lever and a return spring;

The rotating gear is arranged in the fuel passage and connected to one side of the shielding sphere, and the rotating direction of the rotating gear is consistent with the rotating direction of the shielding sphere;

The trigger rod penetrates the shield body and can move back and forth along the axial direction of the shield body; the first end of the trigger rod exposes one end of the shield body, and the second end penetrates into the fuel channel And is a straight rack meshed with the rotating gear;

The return spring is positioned in one end of the shielding main body and sleeved on the first end of the trigger rod to drive the trigger rod to move and reset.

Preferably, the self-rotating shielding device further includes at least one set of supporting components arranged corresponding to the linkage component;

The support assembly includes a support shaft and a bearing; the support shaft penetrates the shield body and is connected to the rotating gear, the bearing is fitted between the support shaft and the rotating gear, and the rotating gear passes through the bearing It is rotatable relative to the supporting shaft.

Preferably, the shielding body includes a columnar shielding base and a pressing plate; the shielding base is provided with a central channel penetrating opposite ends of the shielding base, and the pressing plate is provided with a central through hole;

The shielding sphere is accommodated in the central passage, and the pressing plate is arranged at one end of the shielding base and is covered on the shielding sphere to restrict the shielding sphere in the central passage; the center The through hole communicates with the central passage to form the fuel passage;

The pressure plate is provided with a slot hole corresponding to the trigger rod, the trigger rod is inserted in the slot hole, the first end exposes the pressure plate, and the second end passes through the slot hole and is opposite to the rotating gear. Meshing.

Preferably, the return spring is sleeved on the first end of the trigger rod and is accommodated in the slot; the end of the first end of the trigger rod that exposes the pressure plate is provided with a baffle, so A positioning step is provided in the slot hole through an inner recess, and both ends of the return spring abut the baffle and the positioning step respectively;

The trigger rod moves under the action of an external force and then compresses the return spring; the return spring stretches under the action of the restoring force to drive the trigger rod to move and reset.

Preferably, a concave annular step is provided on the side of the pressure plate facing away from the shielding base, and the annular step is formed on the periphery of the central through hole and communicates with the central through hole;

The slot hole penetrates the two opposite surfaces of the pressing plate between the bottom surface and the side wall of the annular step; the first end of the trigger rod exposes the annular step in the slot hole.

Preferably, a stopper for preventing the trigger rod from falling out of the slot is provided on the side of the pressure plate facing away from the shielding base; the stopper is located in the slot that penetrates the side wall of the annular step Section above.

Preferably, the self-rotating shielding device further includes an outer gear ring that drives the self-rotating shielding device to rotate under an external driving force; the outer gear ring is sleeved and fixed on the outer circumference of the shielding body.

Preferably, a scale is provided on the outer gear ring.

Preferably, a protruding annular protrusion is provided on the outer periphery of the shielding body; the outer gear ring is supported and fixed on the annular protrusion.

The present invention also provides a method for using the self-rotating shielding device, which includes the following steps:

S1. Docking the self-rotating shielding device according to any one of claims 1-10 with external fuel assembly handling equipment;

S2, the external fuel assembly loading and unloading equipment presses down the linkage assembly of the self-rotating shielding device under the action of gravity;

S3. The linkage assembly acts to drive the shielding sphere of the self-rotating shielding device to rotate until the sphere passage of the shielding sphere is in parallel communication with the fuel passage in the shield body, and the fuel passage is opened;

S4. The fuel assembly enters or leaves the core through the fuel passage.

Preferably, the method of using the self-rotating shielding device further includes the following steps:

S5. Disconnect the self-rotating shielding device from the external fuel assembly handling equipment;

S6. The linkage assembly acts to reset under its own restoring force, and drives the shield sphere to rotate until the sphere channel of the shield sphere is staggered with the fuel channel in the shield body, closing the fuel channel.

Beneficial effect

The self-rotating shielding device of the present invention is used for radiation shielding during fuel assembly loading and unloading. According to the passing requirements of the fuel assembly during the loading and unloading process, its linkage assembly can act under the action of external force (such as external fuel assembly loading and unloading equipment) to drive the shielding sphere The rotation realizes the opening and closing of the fuel passage, so that the external fuel assembly handling equipment can perform the loading and unloading operation of the fuel assembly. There is no need for personnel to open or close the fuel channel, reducing the risk of personnel being exposed to radiation; shortening the operation process and improving efficiency.

Description of the drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the accompanying drawings:

FIG. 1 is a schematic diagram of a three-dimensional structure of a self-rotating shielding device according to an embodiment of the present invention;

2 is a schematic cross-sectional structure diagram of a spin shielding device according to an embodiment of the present invention.

Embodiments of the present invention

In order to have a clearer understanding of the technical features, objectives and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the self-rotating shielding device according to an embodiment of the present invention is used for loading and unloading fuel assemblies. The self-rotating shielding device may include a shielding body 10, a shielding sphere 20 and at least one set of linkage components 30.

Wherein, the shield body 10 is provided with fuel passages 100 passing through opposite ends of the shield body 10 for the passage of fuel assemblies. The shielding sphere 20 is rotatably disposed in the fuel passage 100, and the shielding sphere 20 is provided with a sphere passage 200 passing through opposite ends of the shielding sphere 20. The spherical passage 200 can communicate with the fuel passage 100 for the fuel assembly to pass through. According to the fuel assembly, the main passing portion of the fuel passage 100 and the spherical passage 200 are preferably arranged as square passages.

The linkage assembly 30 penetrates into one end of the shield body 10 and is connected to the shield sphere 20 for driving the rotation of the shield sphere 20. One end of the linkage assembly 30 is exposed on one end of the shielding body 10, and under the action of external force, the shielding ball 20 is driven to rotate back and forth between a first position and a second position. When the shielding sphere 20 is in the first position, the sphere passage 200 and the fuel passage 100 are connected in parallel, and the fuel passage 100 is opened. When the shielding sphere 20 is in the second position, the sphere passage 200 is offset from the fuel passage 100 (as shown in FIG. 2), and the fuel passage 200 is closed.

Specifically, in the present invention, the shielding body 10 serves as a support structure of the spin shielding device, which is made of shielding material, has a radiation shielding function and has a certain structural strength. The shielding body 10 may be an integral structure or a separate structure. In this embodiment, as shown in FIG. 2, the shielding body 10 includes a shielding base 11 and a pressing plate 12. The shielding base 11 has a columnar structure, and a central channel 110 penetrating opposite ends of the shielding base 11 is provided, and the shielding sphere 20 is accommodated in the central channel 110. The pressing plate 12 is arranged on one end of the shielding base 11 and can be fixedly connected to the shielding base 11 through a number of connecting pieces. The pressing plate 12 is simultaneously covered on the shielding sphere 20 on one end of the shielding base 11 to restrict the shielding sphere 20 in the central channel 110. The pressure plate 12 is provided with a central through hole 120, and the central through hole 120 communicates with the central channel 110 to form a fuel channel 100.

In order to better connect and cooperate to form the shielding body 10, the pressing plate 12 may be partially fitted to the inner side of one end of the shielding base 11, and partially fitted on the end surface of the shielding base 11 to be connected to it.

The fuel passage 100 may include an accommodating portion and an opening connected to both ends of the accommodating portion in its length. The accommodating portion and an opening are opened on the shielding base 11, that is, formed by the central channel 110; the central through hole 120 on the pressure plate 12 forms another opening. The accommodating part has a size larger than the shielding sphere 20 and is used for accommodating the shielding sphere 20 and facilitating the rotation of the shielding sphere 20 therein. The two openings are set according to the peripheral shape of the fuel assembly, such as square holes,

The ball channel 200 on the shielding ball 20 may be arranged corresponding to the shape of the opening. When the shielding sphere 20 opens the fuel passage 100 (that is, in the first position), the sphere passage 200 communicates with the two openings on both sides thereof, and the sphere passage 200 also constitutes the inner passage of the fuel passage 100 for the passage of fuel assemblies . After the shielding sphere 20 rotates relative to the shielding body 10 (that is, in the second position), the sphere passage 200 is staggered with the fuel passage 100 in the shielding body 10 to form a certain included angle (can be an acute angle or a right angle), and the fuel passage is cut off 100, that is, the fuel passage 100 is closed, and the fuel assembly cannot pass through.

The shielding ball 20 is made of a shielding material. The shield sphere 10 is inside the shield body 10, and the spherical surfaces at the upper and lower ends of the shield sphere 10 can be arc-shapedly connected with the inner peripheral sides of the upper and lower ends of the fuel channel 100 to ensure a certain degree of sealing and ensure that the shield sphere 20 can rotate smoothly.

The linkage assembly 20 is mainly used to act under the gravity of the external fuel assembly loading and unloading equipment to drive the shielding sphere 10 to rotate, without requiring personnel to operate, and reducing the risk of radiation to personnel. Alternatively, the linkage assembly 30 is provided with at least two groups, which are respectively connected to at least two opposite sides of the shield sphere 20 to drive the entire shield sphere 20 to rotate in a stable and balanced manner.

The linkage assembly 30 may include a rotating gear 31, a trigger lever 32 and a return spring 33.

The rotating gear 31 is disposed in the fuel passage 100 (specifically, the central passage 110) and connected to one side of the shield sphere 20. The rotating direction of the rotating gear 31 is consistent with the rotating direction of the shielding sphere 20, and the two are relatively fixed, so that when the rotating gear 31 rotates, the shielding sphere 20 is also driven to rotate.

The trigger rod 32 passes through the shield body 10 and can move back and forth along the axial direction of the shield body 10. The trigger rod 32 includes a first end and a second end opposite to each other in its length, and the second end is a straight rack. The first end of the trigger rod 32 is exposed at one end of the shield body 10 and serves as a gravity force application part of the external fuel assembly handling equipment. The second end of the trigger rod 32 penetrates the fuel passage 100 and meshes with the rotating gear 31. The return spring 33 is positioned in one end of the shield body 10 and sleeved on the first end of the trigger rod 32 to drive the trigger rod 32 to move and reset.

When the gravity of the external fuel assembly loading and unloading equipment acts on the trigger rod 32, the trigger rod 32 is driven to move (downward) into the fuel passage 100, and the return spring 33 is compressed. The movement of the trigger lever 32 drives the rotating gear 31 meshed with it to rotate, thereby driving the shielding ball 20 to rotate. When the gravitational action of the external fuel assembly loading and unloading equipment is cancelled, the return spring 33 expands due to its own restoring force, driving the trigger rod 32 to move in the reverse direction (upward) to reset, and then drive the shielding ball 20 to rotate in the reverse direction.

In this embodiment, corresponding to the split structure of the shield body 10, the linkage assembly 30 penetrates the pressure plate 12 and extends into the fuel channel 100 to connect to the shield sphere 20. Therefore, the pressure plate 12 is provided with a slot hole 121 corresponding to the trigger rod 32. The slot hole 121 penetrates two opposite surfaces of the pressure plate 12. The trigger rod 32 penetrates into the slot 121 from the pressure plate 12, the first end exposes the pressure plate 12 to facilitate the application of gravity by external fuel assembly handling equipment, and the second end (straight rack) passes through the slot 121 to mesh with the rotating gear 31.

Further, a concave annular step 122 is provided on the side of the pressing plate 12 facing away from the shielding base 11, and the annular step 122 is formed on the periphery of the central through hole 120 and communicates with the central through hole 120. The slot 121 penetrates the two opposite surfaces of the pressure plate 12 between the bottom surface and the side wall of the annular step 122, so that a part of the slot 121 in the circumferential direction is located on the bottom surface of the annular step 122, and the other part is located on the side wall and the annular step of the annular step 122. 122 on the outer periphery of the pressure plate 12 part. The first end of the trigger rod 32 exposes the annular step 122 in the slot 121, which is convenient for the external fuel assembly handling equipment to act on the annular step 122 to drive the trigger rod 32 to move, and it also prevents the trigger rod 32 from protruding to the periphery of the annular step 122. There is a risk of misoperation on the surface of the pressing plate 12.

A stop 123 is provided on the side of the pressing plate 12 facing away from the shielding base 11. The stopper 123 is located above the part of the slot 121 passing through the side wall of the annular step 122 to prevent the trigger rod 32 from falling out of the slot 121. Preferably, a notch (not shown) adapted to the stopper 123 is provided on the side of the pressing plate 12 facing away from the shielding base 11, and the notch is located on the outer periphery of the annular step 122 and communicates with the annular step 122. The stopper 123 is fitted to the notch above the slot 121 to resist the trigger lever 32 and to ensure the overall appearance of the pressure plate 12 without affecting the trigger lever 32 to expose the annular step 122 for external force.

The return spring 33 is sleeved on the first end of the trigger rod 32 and is accommodated in the slot 121. In order to position the return spring 33, the first end of the trigger lever 32 is provided with a baffle 34 at the end that exposes the pressing plate 12, a positioning step (not shown) is recessed in the slot 121, and the return spring 33 is in the slot 121 It is sleeved on the first end of the trigger rod 32, and its two ends respectively abut against the baffle 34 and the positioning step. After the trigger rod 32 moves under the action of external force, the return spring 33 is compressed; the return spring 33 expands under the action of the restoring force to drive the trigger rod 32 to move and reset.

Further, as shown in FIGS. 1 and 2, in order to make the shielding sphere 20 rotate stably in the shielding body 10, the self-rotating shielding device of the present invention further includes at least one set of support components 40, and each set of support components 40 is linked to The component 30 is correspondingly set.

Alternatively, the support assembly 40 may include a support shaft 41 and a bearing 42. The support shaft 41 can penetrate into the shield main body 10 from the outer peripheral side of the shield main body 10 and be connected to the rotating gear 31, and the support shaft 41 is relatively fixed to the shield main body 10. The bearing 42 is fitted between the supporting shaft 41 and the rotating gear 31 to effectively reduce rotational friction. The rotating gear 31 is rotatable relative to the supporting shaft 41 through the bearing 42. Corresponding to the position of the shielding sphere 20 in the shielding body 10, the support shaft 41 mainly penetrates the shielding base 11 to the fuel passage 100 from the outer peripheral side of the shielding base 11, and is connected to the rotating gear 31.

The self-rotating shielding device of the present invention further includes an outer gear ring 50 sheathed and fixed on the outer circumference of the shield body 10. The outer gear ring 50 is used to cooperate with an external driving device to drive the self-rotating shielding device to rotate as a whole under the external driving force, so as to adjust the direction of the fuel channel 100.

According to needs, a scale (not shown) may be provided on the outer gear ring 50 to facilitate obtaining the rotation angle of the outer gear ring 50 and the entire self-rotating shielding device.

The outer gear ring 50 is an annular structure with teeth provided on the outer peripheral surface, and can be fixed on the outer periphery of the shielding base 11 by bolts and other connectors. Corresponding to the outer gear ring 50, the outer circumference of the shield base 11 of the shield body 10 is provided with a protruding annular protrusion 111, and the outer gear ring 50 is supported and fixed on the annular protrusion 111.

The self-rotating shielding device of the present invention is used for loading and unloading fuel assemblies, and is docked with external fuel assembly loading and unloading equipment during the loading and unloading of fuel assemblies. The fuel assemblies enter or leave the core through the fuel passage 100 of the spinning shielding device.

Referring to Figures 1 and 2, the method of using the self-rotating shielding device of the present invention may include the following steps:

S1. Docking the self-rotating shielding device with the external fuel assembly handling equipment.

In a natural state, the fuel passage 100 of the spin shield device is in a closed state.

S2. The external fuel assembly handling equipment presses down the linkage assembly 30 of the self-rotating shielding device under the action of gravity.

S3. The linkage assembly 30 acts to drive the shielding sphere 20 of the self-rotating shielding device to rotate until the sphere passage 200 of the shielding sphere 20 is in parallel communication with the fuel passage 100 in the shielding body 10, and the fuel passage 100 is opened.

Specifically, the trigger rod 32 of the linkage assembly 30 moves downward under the action of the gravity of the external fuel assembly handling equipment, and the straight rack of the trigger rod 32 drives the rotating gear 31 meshed with it to rotate, thereby driving the shield sphere 20 to support the shaft 41 as The center of rotation rotates by a certain angle, such as 90°, until the spherical passage 200 and the fuel passage 100 are connected in parallel, and the fuel passage 100 is opened.

S4. The fuel assembly enters or leaves the core through the fuel passage 100.

S5. Separate the self-rotating shielding device from the external fuel assembly handling equipment.

S6. The linkage assembly 30 acts to reset under its own restoring force, and drives the shield sphere 20 to rotate until the sphere passage 200 of the shield sphere 20 is offset from the fuel passage 100 in the shield body 10, and the fuel passage 100 is closed.

In this step S6, when the external fuel assembly loading and unloading equipment is disengaged, the trigger lever 32 of the linkage assembly 30 moves upward under the action of the restoring force of the return spring 33, and the straight rack of the trigger lever 32 drives the rotating gear 31 meshed with it to rotate. In turn, the shield sphere 20 is driven to rotate in the opposite direction by a certain angle (such as 90°) with the support shaft 41 as the center of rotation, until the sphere passage 200 and the fuel passage 100 are staggered, and the fuel passage 100 is closed.

In the above-mentioned method of use, the fuel assembly enters the core through the fuel channel 100 to realize the charging of the fuel assembly; the fuel assembly is separated from the core through the fuel channel 100 to realize the unloading of the fuel assembly.

The above are only the embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the description and drawings of the present invention, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of the present invention.

Claims

A self-rotating shielding device for loading and unloading fuel assemblies, wherein the self-rotating shielding device includes a shielding body, a shielding sphere, and at least one set of linkage components;

The shielding body is provided with fuel passages penetrating opposite ends of the shield body and used for the passage of fuel assemblies; the shielding sphere is rotatably arranged in the fuel passage, and the shielding sphere is provided with spheres penetrating the opposite ends of the shielding sphere. aisle;

The interlocking component penetrates into one end of the shielding body and is connected to the shielding sphere; one end of the interlocking component is exposed on one end of the shielding body, and under the action of external force, the shielding sphere is actuated to drive the shielding sphere to a first Rotate back and forth between position and a second position;

When the shielding sphere is in the first position, the sphere passage and the fuel passage are connected in parallel to open the fuel passage;

When the shielding sphere is in the second position, the sphere passage is staggered from the fuel passage, and the fuel passage is closed.
The self-rotating shielding device according to claim 1, wherein the linkage assembly includes a rotating gear, a trigger lever, and a return spring;

The rotating gear is arranged in the fuel passage and connected to one side of the shielding sphere, and the rotating direction of the rotating gear is consistent with the rotating direction of the shielding sphere;

The trigger rod penetrates the shield body and can move back and forth along the axial direction of the shield body; the first end of the trigger rod exposes one end of the shield body, and the second end penetrates into the fuel channel And is a straight rack meshed with the rotating gear;

The return spring is positioned in one end of the shielding main body and sleeved on the first end of the trigger rod to drive the trigger rod to move and reset.
The self-rotating shielding device according to claim 2, wherein the self-rotating shielding device further comprises at least one set of supporting components arranged corresponding to the linkage component;

The support assembly includes a support shaft and a bearing; the support shaft penetrates the shield body and is connected to the rotating gear, the bearing is fitted between the support shaft and the rotating gear, and the rotating gear passes through the bearing It is rotatable relative to the supporting shaft.
The self-rotating shielding device according to claim 2, wherein the shielding body comprises a columnar shielding base and a pressing plate; the shielding base is provided with a central channel passing through opposite ends of the shielding base, and the pressing plate is provided with a center Through hole

The shielding sphere is accommodated in the central passage, and the pressing plate is arranged at one end of the shielding base and is covered on the shielding sphere to restrict the shielding sphere in the central passage; the center The through hole communicates with the central passage to form the fuel passage;

The pressure plate is provided with a slot hole corresponding to the trigger rod, the trigger rod is inserted in the slot hole, the first end exposes the pressure plate, and the second end passes through the slot hole and is opposite to the rotating gear. Meshing.
The self-rotating shielding device according to claim 4, wherein the return spring is sleeved on the first end of the trigger rod and is accommodated in the slot; the first end of the trigger rod A baffle is provided at the end exposing the pressure plate, a positioning step is recessed in the slot, and both ends of the return spring abut the baffle and the positioning step respectively;

The trigger rod moves under the action of an external force and then compresses the return spring; the return spring stretches under the action of the restoring force to drive the trigger rod to move and reset.
The self-rotating shielding device according to claim 4, wherein a concave annular step is provided on the side of the pressing plate facing away from the shielding base, and the annular step is formed on the periphery of the central through hole and Communicate with the central through hole;

The slot hole penetrates the two opposite surfaces of the pressing plate between the bottom surface and the side wall of the annular step; the first end of the trigger rod exposes the annular step in the slot hole.
The self-rotating shielding device according to claim 6, wherein a stopper for preventing the trigger rod from coming out of the slot is provided on the side of the pressure plate facing away from the shielding base; the stopper is located at Above the slotted portion passing through the side wall of the annular step.
The self-rotating shielding device according to any one of claims 1-7, wherein the self-rotating shielding device further comprises an outer gear ring that drives the self-rotating shielding device to rotate under an external driving force; the outer gear ring It is sleeved and fixed on the outer circumference of the shielding main body.
8. The self-rotating shielding device according to claim 8, wherein the outer gear ring is provided with a scale.
8. The self-rotating shielding device according to claim 8, wherein a protruding annular protrusion is provided on the outer periphery of the shielding body; the outer gear ring is supported and fixed on the annular protrusion.
A method for using a self-rotating shielding device is characterized in that it comprises the following steps:

S1. Docking the self-rotating shielding device according to any one of claims 1-10 with external fuel assembly handling equipment;

S2, the external fuel assembly loading and unloading equipment presses down the linkage assembly of the self-rotating shielding device under the action of gravity;

S3. The linkage assembly acts to drive the shielding sphere of the self-rotating shielding device to rotate until the sphere passage of the shielding sphere is in parallel communication with the fuel passage in the shield body, and the fuel passage is opened;

S4. The fuel assembly enters or leaves the core through the fuel passage.
The method of using the self-rotating shielding device according to claim 11, further comprising the following steps:

S5. Disconnect the self-rotating shielding device from the external fuel assembly handling equipment;

S6. The linkage assembly acts to reset under its own restoring force, and drives the shield sphere to rotate until the sphere channel of the shield sphere is staggered with the fuel channel in the shield body, closing the fuel channel.