A heavy water reactor post-irradiation target canister transfer apparatus and method

Abstract

This invention relates to the field of target box transportation technology after heavy water reactor irradiation. Addressing the problem that existing transportation channels cannot effectively reduce radiation exposure to personnel during the transportation of radioactive target boxes, this invention provides a target box transportation device after heavy water reactor irradiation, comprising a transportation pipe, a shielded transfer container, and a conveyor belt. A negative pressure is established within the transportation pipe to draw the target box into a vertical section. A separator is installed on the vertical section of the transportation pipe to allow the target boxes to enter the shielded transfer container one by one within a shielded box. The shielded transfer container is transported via the conveyor belt. Furthermore, this invention also provides a method for transporting target boxes after heavy water reactor irradiation, sequentially loading the target boxes from the vertical section into designated positions within the shielded transfer container in the shielded box, and completing radiation protection treatment of the target boxes within the shielded box. By loading the irradiated target boxes into a shielded working box, compared to containerized transport, the dose rate in the operation and maintenance area can be reduced from 2 mSv / h to 25 μV / h, significantly reducing the dose level for operators.

Description

Technical Field

[0001] This invention relates to the field of target box transfer technology after heavy water reactor irradiation, and particularly to a target box transfer device and method after heavy water reactor irradiation. Background Technology

[0002] Heavy water reactors have high neutron flux in their cores, allowing technicians to install irradiation devices at observation ports for purposes such as producing medical isotopes. The target box contains the material to be irradiated and is introduced into the heavy water reactor core through the irradiation device, where it is irradiated. After irradiation, the irradiation device removes the target box from the core and discharges it through the device's discharge port. The irradiated target box is radioactive.

[0003] Chinese patent CN202210636177.5 (hereinafter referred to as the patent) describes a system and method for producing radioactive isotopes using a heavy water reactor nuclear power plant, and recommends a design scheme. In this design scheme, a production channel is installed in the observation port of the heavy water reactor, and the production channel is inserted into the heavy water reactor core. This design scheme provides a channel for entering and exiting the heavy water reactor core. The target box removed from the core leaves the production channel by its own weight and enters an automated transport channel, which transports the target box to a position away from the top of the heavy water reactor.

[0004] Clearly, the automated transport tunnel provided by this patent is large. However, the top of a heavy water reactor houses numerous critical devices, such as reactor flux measurement mechanisms, shutdown rod drive mechanisms, and regulating rod drive mechanisms, leaving insufficient space for an automated transport tunnel. Even if the top of the heavy water reactor were modified, the on-site modification work would be substantial due to space constraints. Furthermore, the automated transport tunnel must meet seismic resistance requirements, and the narrow tunnel path makes anchoring the foundation of the automated transport tunnel structure difficult.

[0005] Furthermore, the patented automated transport channel transfers containers containing radioactive target boxes. All target boxes unloaded from the reactor core are contained within these containers and transported in a single operation. The large number of targets transferred at once, coupled with the high radioactive dose, necessitates shielding measures. However, due to space constraints, the containers cannot simultaneously meet both size (loading) and shielding requirements. Meeting the container loading requirements necessitates reducing the shielding thickness; conversely, meeting the shielding requirements results in a thick container wall, insufficient internal volume for target box loading, and the weight of the containers makes it difficult to meet seismic resistance requirements. Target boxes are poured from the containers into the shielding transport container, and an automatic closing mechanism closes the container. During the container pouring and closing process, limited shielding means personnel can only operate remotely. In case of malfunction, operators cannot quickly access the container. Adding temporary shielding measures under these circumstances presents significant implementation challenges and hinders rapid and effective troubleshooting. Moreover, the automated transport channel's handling of containers within a confined space presents significant construction challenges.

[0006] In addition, in this patent, the target boxes are poured into the shielding container in an disorderly manner, which is not conducive to fixing the target boxes during transportation, such as fixing and removing the target boxes in the shielding container, and increases the complexity of downstream processes. Summary of the Invention

[0007] The main objective of this invention is to provide a target box transport device and method after heavy water reactor irradiation, which solves the problem that existing transport channels cannot effectively reduce radiation exposure to personnel when transporting radioactive target boxes.

[0008] Another objective of this invention is to provide a target box transport device after heavy water reactor irradiation, which solves the problem that existing transport channels are too large to be arranged on the top of the heavy water reactor.

[0009] Another objective of this invention is to provide a target box transport device after heavy water reactor irradiation, which solves the problem that existing transport channels cannot realize the movement, lifting, and turning functions of the target box in the confined space on site.

[0010] Another objective of this invention is to provide a target box transfer device after heavy water reactor irradiation, which solves the problem that the target box cannot simultaneously meet the size and shielding requirements.

[0011] Another objective of this invention is to provide a target box transfer device after heavy water reactor irradiation, which solves the problem that due to limited shielding measures, it is impossible to quickly and effectively handle fault situations.

[0012] Another objective of this invention is to provide a target box transport device after heavy water reactor irradiation, which solves the problem of difficulty in fixing the target box during the transport process in existing transport channels.

[0013] Another objective of this invention is to provide a target box transfer device after heavy water reactor irradiation, which solves the problem that the target box is inconvenient to remove from the shielding container, thus increasing the complexity of downstream processes.

[0014] Another objective of this invention is to provide a target box transfer device after heavy water reactor irradiation, which solves the problem of disordered target box loading.

[0015] To achieve the above objectives, the present invention provides the following technical solution:

[0016] A target box transfer device after heavy water reactor irradiation includes: a transfer pipe for receiving target boxes and passing through the top of the heavy water reactor, having a vertical section, a portion of which is inserted into a shielded box, a separator on the vertical section to allow the target boxes to enter the shielded box one by one, a vacuum pump on the transfer pipe to create negative pressure within the transfer pipe to draw the target boxes into the vertical section; a shielded transfer container for loading the target boxes, the inner cover of which is installed or removed by an inner cover lifting device mounted on the shielded box; and a conveyor belt for transporting the shielded transfer container into or out of the shielded box.

[0017] In one possible implementation, the separator includes a target separation cylinder and a pin connected to the front end of the target separation cylinder, the target separation cylinder driving the pin to move.

[0018] As one possible implementation, the vertical section is provided with a nozzle, through which the pin enters and exits the transmission tube.

[0019] As one possible implementation, the transmission pipe is provided with a control ball valve below the separator installation position, the control ball valve connecting the upper and lower parts of the vertical section into one unit.

[0020] As one possible implementation, the control ball valve has a channel with the same inner diameter as the transmission pipe. When the control ball valve is open, the inside of the control ball valve forms a channel with the transmission pipe, allowing the target box to enter the shielding box through the control ball valve. When the control ball valve is closed, the transmission pipe is sealed to create a negative pressure at the inlet of the transmission pipe, allowing the target box to enter the vertical section.

[0021] As one possible implementation, the transmission pipe is fitted with a telescopic sleeve that extends into the shielding box. The telescopic sleeve is driven by a telescopic cylinder to move up and down relative to the transmission pipe.

[0022] As one possible implementation, the vacuum pump is connected to the vertical section via a pipeline equipped with a control valve assembly.

[0023] As one possible approach, the vertical section is inserted vertically into the shielding box.

[0024] As one possible approach, a counter is fitted onto the vertical section to record the number of target boxes entering the vertical section.

[0025] As one possible implementation, the inlet of the transmission tube is connected to a target box receiving slot, which is used to receive the target box falling from the discharge port of the irradiation device.

[0026] As one possible implementation, the target box is cylindrical in shape with arc-shaped ends.

[0027] As one feasible approach, the shielding box is a lead-shielded box with two spaced-apart lifting holes and sleeve holes at the top, a channel at the front end to allow the conveyor belt to enter and exit the shielding box, and an opening at the rear end for installing an observation window.

[0028] As one possible implementation, the shielded transport container includes an inner cover, a basket, and a cylinder, with the basket disposed within the cylinder.

[0029] As one possible implementation, the cylinder has a stepped cylindrical cavity, and the inner cover is a stepped cylinder that is fitted and installed with the upper part of the stepped cylindrical cavity.

[0030] As one possible implementation, the top of the inner cover is provided with an inner cover hole with a stepped shape, the upper hole diameter of the inner cover hole is smaller than the lower hole diameter, and the connection part between the upper hole and the lower hole is provided with an arc-shaped structure.

[0031] As one feasible approach, the suspended platform is a two-layer disc-shaped structure, including an upper suspended platform and a lower suspended platform. The upper suspended platform has multiple through holes evenly arranged along the circumference, and the lower suspended platform has multiple deep holes evenly arranged along the circumference. The upper and lower suspended platforms have the same size, number of holes, and distribution spacing.

[0032] As one feasible approach, a first control lever is provided in the middle of the upper suspended basket, which is used for downstream processes to extract and transfer the upper suspended basket, and a second control lever is provided in the middle of the lower suspended basket, which is used for downstream processes to extract and transfer the lower suspended basket.

[0033] As one possible implementation, the shielded transfer container also includes an outer cover, which is a disc with a central opening connected to the cylinder body, restricting the axial movement of the inner cover and the basket.

[0034] As one possible implementation, the conveyor belt includes a frame, an intermediate conveying mechanism, and an inner conveying trolley, the inner conveying trolley being slidably disposed on the intermediate conveying mechanism, and the intermediate conveying mechanism being slidably disposed on the frame.

[0035] As one feasible approach, the frame is installed inside the shielded box and includes two relatively parallel C-shaped channel steels and several transverse supports connecting the two C-shaped channel steels. One end of one of the C-shaped channel steels is equipped with a transmission belt drive motor and a gearbox, and the other end is equipped with a driven sprocket. The driven sprocket is connected to the drive sprocket in the gearbox via a chain.

[0036] As one possible implementation, the conveyor belt drive motor is connected to the horizontal bevel gear in the gearbox via a coupling, the drive sprocket and the vertical bevel gear are mounted on the same shaft, and the vertical bevel gear meshes with the horizontal bevel gear.

[0037] As one feasible approach, the intermediate conveying mechanism includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. Rollers are installed at both ends of the outer side of the C-shaped channel steels of the intermediate conveying mechanism. One end of the intermediate conveying mechanism is fixedly connected to the shielding door, and the other end is installed inside the C-shaped channel steel of the frame. The inner side of the C-shaped channel steel of the frame is provided with a stop block to limit the movement stroke of the intermediate conveying mechanism and prevent the intermediate conveying mechanism from detaching from the frame.

[0038] As one feasible approach, the inner conveying trolley includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. Guide wheels are installed at both ends of the outer side of the C-shaped channel steels of the inner conveying trolley. The guide wheels move along the inner side of the C-shaped channel steels of the intermediate conveying mechanism. The two ends of the C-shaped channel steels of the intermediate conveying mechanism are closed to prevent the inner conveying trolley from detaching from the intermediate conveying mechanism.

[0039] As one feasible approach, a drive plate is installed on the inner layer conveying trolley, with one end of the drive plate welded to the inner layer conveying trolley and the other end located above the chain. The drive plate and the chain are connected by a connector.

[0040] As one possible implementation, the inner transport trolley is equipped with a turntable that carries and rotates the shielded transfer container.

[0041] In one possible implementation, the turntable includes a gear disk, a drive wheel, and a turntable drive motor. The shielded transfer container is placed on the gear disk, the turntable drive motor is connected to the drive wheel, and the drive wheel meshes with the gear disk.

[0042] As one feasible method, the conveyor belt is provided with a drag chain, one end of which is fixedly installed on the frame and the other end is installed on the turntable.

[0043] As one feasible approach, the conveyor belt is equipped with a target box loading position, an inner cover operation position, and a shielded transfer container hoisting position. When the conveyor belt is in the target box loading position, the shielding door is closed, and the target boxes are loaded into the shielded transfer container one by one. When the conveyor belt is in the inner cover operation position, the shielding door is closed, and the inner cover is hoisted or installed using the inner cover hoisting tool. When the conveyor belt is in the shielded transfer container hoisting position, the shielding door is open, and the shielded transfer container is hoisted in or out using an external crane.

[0044] As one possible implementation, the shielding box is provided with a manual operation hole, and a removable plug is installed on the manual operation hole. A rotating tool passes through the manual operation hole and drives the conveyor belt to the inner cover operation position by manual drive.

[0045] As one feasible method, the inner cover lifting device includes a locking pin, a control lever, a movable inner rod, an outer cylinder, a guide head, and a ball pin. The movable inner rod is located inside the outer cylinder, and a C-shaped groove is provided on the outer cylinder. The control lever is connected to the movable inner rod through the C-shaped groove. The lower end of the movable inner rod is provided with a tapered body, and the tapered body pushes the ball pin to extend out of the guide head.

[0046] As one possible implementation, the guide head has three spherical holes along the circumferential radial direction at its middle section, and the three ball pins are disposed in the spherical holes.

[0047] As one possible implementation, the inner cover lifting device also includes a lifting ring that is threadedly connected to the cap at the upper end of the outer cylinder.

[0048] As one feasible approach, the inner cover lifting device is hoisted by a crane outside the shielding box.

[0049] As one feasible approach, a gamma probe and a camera are installed inside the shielded box.

[0050] A method for transporting target boxes after heavy water reactor irradiation includes: establishing a negative pressure environment inside a transport pipe; sequentially drawing target boxes from the inlet of the transport pipe into a vertical section of the transport pipe; sequentially loading the target boxes in the vertical section into designated positions within a shielded transport container in a shielded box; and after the shielded transport container is filled, installing an inner cover inside the shielded box and an outer cover outside the shielded box.

[0051] Furthermore, the above-mentioned target box transfer method after heavy water reactor irradiation specifically includes the following steps:

[0052] Step 1: Establish negative pressure in the transmission tube and transfer the target box from the target box receiving slot to the vertical section using negative pressure.

[0053] Step 2: Open the shielding door, place the shielded transfer container on the turntable of the inner conveyor trolley, and remove the outer cover;

[0054] Step 3: The inner layer conveying trolley moves the shielding transfer container to the inner cover operation position, the inner cover tool lifts the inner cover, the inner layer conveying trolley moves the shielding transfer container to the target box loading position, and the shielding door is closed;

[0055] Step 4: Insert the target boxes in the vertical section into the holes of the basket inside the shielded transfer container in sequence;

[0056] Step 5: Install the inner cover onto the top of the shielded transport container inside the shielded box;

[0057] Step 6: Transport the shielded transfer container out of the shielded box via a conveyor belt, and install the outer cover on the shielded transfer container;

[0058] Step 7: Transport the shielded transport container to the designated location.

[0059] Further, step 1 includes:

[0060] Close the control ball valve, retract the separator pin, and start the vacuum pump;

[0061] As the trolley moves within the production channel, the target boxes are sucked into the vertical section one by one, and a counter counts the target boxes entering the vertical section.

[0062] Further, step 2 includes:

[0063] The conveyor belt drive motor moves the inner layer conveyor trolley to the hoisting position of the shielded transfer container;

[0064] The factory crane places the shielded transfer container on the turntable of the inner conveyor trolley and removes the outer cover.

[0065] Furthermore, step 3 includes:

[0066] The conveyor belt drive motor moves the inner layer conveying trolley to the inner cover operation position. The crane inserts the inner cover tool into the hole of the inner cover. After it is in place, the inner cover lifting tool is locked to the inner cover, the locking pin is inserted, and the inner cover is lifted away from the shielded transfer container to a preset height.

[0067] The conveyor belt drive motor moves the inner layer conveyor trolley to the target box loading position and closes the shielding door.

[0068] Furthermore, step 4 includes:

[0069] The telescopic cylinder drives the telescopic sleeve to descend to a preset position above the basket;

[0070] The turntable drive motor rotates the shielded transfer container, axially aligning one hole of the suspended basket with the telescopic sleeve;

[0071] The target separation cylinder drives the pin to insert between the two target boxes;

[0072] Open the control ball valve, and the target box falls into the basket hole by gravity;

[0073] Close the control ball valve, retract the pin, the next target box falls onto the control ball valve, and then insert the pin again;

[0074] The turntable drive motor rotates the shielded transfer container to the next empty position of the suspended basket, aligning it with the telescopic sleeve;

[0075] Repeat the above steps to insert all the target boxes into the holes of the basket.

[0076] Furthermore, step 5 includes:

[0077] The telescopic cylinder drives the telescopic sleeve to lift it to the preset position.

[0078] The conveyor belt drive motor moves the inner layer conveying trolley to the inner cover operation position;

[0079] Operate the inner cover lifting tool to install the inner cover onto the shielded transfer container, unlock the inner cover lifting tool, and lift it to the preset position.

[0080] Furthermore, step 6 includes:

[0081] The conveyor belt drive motor moves the inner layer conveyor trolley to the shielding container hoisting position;

[0082] The outer cover is installed on the shielded transport container.

[0083] Compared with the prior art, the post-irradiation target box transfer device and method provided by the present invention have the following beneficial effects:

[0084] The target box after irradiation is loaded in a shielded working box. Compared with the material box transportation, the dose rate in the operation and maintenance area can be reduced from 2msv / h to 25μv / h, which greatly reduces the dose level of operators.

[0085] This invention uses a vacuum pump to establish the gas flow direction, which is more conducive to the target box being drawn into the transmission tube for transmission.

[0086] This invention uses gas-driven transmission via a transmission pipe, which is beneficial for equipment layout in confined spaces.

[0087] The anchoring of the transmission pipe of this invention is simpler and more likely to meet seismic requirements.

[0088] The transmission pipe of this invention is lightweight and small in size, and will not cause adverse effects on surrounding equipment during construction and operation, with a low risk of damage to surrounding equipment.

[0089] This invention enables the target box to decay in the vertical section of the transmission tube, thereby reducing the radioactivity level of the shielded transport container.

[0090] This invention enables individual unloading of the target box, allowing for flexible unloading based on downstream needs. Furthermore, this invention allows the target box to be packaged and transported as needed after leaving the reactor, enabling the production of different types of isotopes within the same irradiation channel.

[0091] Furthermore, the target box receiving slot provided by the present invention can ensure the correct orientation when the target box falls.

[0092] Furthermore, the target box of the present invention can be placed in the basket in an orderly manner, reducing the difficulty of downstream processes.

[0093] Furthermore, the shielding door and the conveyor belt of the present invention are connected together, and the closing of the shielding door is mechanically interlocked with the fuel unloading operation, so that the shielding door is always closed at any time when the radioactive target box is operated inside the shielding box, avoiding personnel from being accidentally exposed to radiation and achieving intrinsic safety. Attached Figure Description

[0094] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below.

[0095] Figure 1 A schematic diagram of the target box transfer device after unloading and entering the irradiated target box provided by the present invention;

[0096] Figure 2 A schematic diagram of the target box entering the target box receiving slot provided by the present invention;

[0097] Figure 3 This is a schematic diagram of the target box provided by the present invention;

[0098] Figure 4 A schematic diagram of the structure of the target box transmission device after irradiation with the shielding door closed, provided by the present invention;

[0099] Figure 5Left view of the post-irradiation target box transmission device without a shielding door provided by the present invention;

[0100] Figure 6 for Figure 4 Enlarged view of point A in the middle;

[0101] Figure 7 A schematic diagram of the structure of the target box transmission device after irradiation with the shielding door open, provided by the present invention;

[0102] Figure 8 This is a schematic diagram of the structure of the conveyor belt in the extended state provided by the present invention;

[0103] Figure 9 A schematic diagram of the structure of the transmission belt in the retracted state provided by the present invention;

[0104] Figure 10 A schematic diagram of the transmission belt gearbox provided by the present invention is shown in cross section, in which the internal structure of the gearbox is shown.

[0105] Figure 11 This is a schematic diagram of the structure of the turntable provided by the present invention;

[0106] Figure 12 A top view of the turntable provided by the present invention;

[0107] Figure 13 This is a schematic diagram of the upper suspended platform provided by the present invention;

[0108] Figure 14 This is a schematic diagram of the structure of the inner cover lifting device provided by the present invention;

[0109] Figure 15 A front view of the inner cover lifting device provided by the present invention;

[0110] Figure 16 for Figure 15 A cross-sectional view along the BB plane;

[0111] Figure 17 This is a top view of the inner cover lifting device provided by the present invention.

[0112] Explanation of reference numerals in the attached figures:

[0113] 1. Irradiation device; 2. Discharge port; 3. Target box; 4. Target box receiving slot; 5. Transfer pipe; 6. Shielding box; 7. Separator; 8. Vacuum pump; 9. Control valve group; 10. Telescopic sleeve; 11. Control ball valve; 12. Counter; 13. Shielding door; 14. Shielding transfer container; 15. Conveyor belt; 16. Inner cover; 17. Inner cover lifting device; 18. Suspended basket; 19. Frame; 20. Intermediate conveyor mechanism; 21. Inner layer conveyor trolley; 22. Drive plate; 23. Driven sprocket; 24. Conveyor belt drive motor; 25. Gearbox; 26. Observation window; 27. Gamma probe 28. Head; 29. ​​Camera; 30. Turntable; 31. Gear disk; 32. Drive wheel; 33. Turntable drive motor; 34. Coupling; 35. Horizontal bevel gear; 36. Cable chain; 37. Crane; 38. Cylinder; 39. Outer cover; 40. Lifting ring; 41. Locking pin; 42. Control lever; 43. Movable inner rod; 44. Outer cylinder; 45. Guide head; 46. Ball pin; 47. Chain; 48. Drive sprocket; 49. Plug; 50. Lower suspended basket; 51. Upper suspended basket; 52. Telescopic tube telescopic cylinder; 53. Target separation cylinder; 54. Roller; 55. Guide wheel. Detailed Implementation

[0114] The following detailed description provides further details on specific implementation methods.

[0115] To facilitate understanding, a brief introduction to the existing irradiation device 1 will be given first. For example... Figure 1 As shown, the irradiation device 1 has a discharge port 2. After the target box 3 is irradiated, the irradiation device 1 removes the target box 3 from the core and discharges it from the discharge port 2.

[0116] like Figures 1 to 17 As shown, the present invention provides a target box transfer and loading device after heavy water reactor irradiation, including a target box receiving slot 4, a transfer pipe 5, a shielding box 6, a separator 7, a shielded transfer container 14, a conveyor belt 15, and an inner cover lifting device 17.

[0117] like Figures 1 to 3 As shown, the target box receiving slot 4 is matched with the unloading port 2 of the irradiation device 1. After irradiation, the target box 3 falls from the unloading port 2 under gravity and enters the target box receiving slot 4. The transmission pipe 5 is connected to the target box receiving slot 4, and the target box receiving slot 4 and part of the transmission pipe 5 are located near the observation port at the top of the heavy water reactor.

[0118] like Figure 2 As shown, the target box receiving slot 4 has a specially designed arc-shaped cross-section. The cross-sectional shape of the target box receiving slot 4 is U-shaped or approximately U-shaped, wider at the top and narrower at the bottom, with smooth curved transitions on both sides. This ensures that the target box 3 is axially parallel when entering the bottom of the target box receiving slot 4, allowing it to slide along the direction of the target box receiving slot 4. It should be noted that the cross-sectional shape of the target box receiving slot 4 is not limited to a U-shape; for example, it can be semi-circular or... The shape is acceptable as long as the target box 3 is axially parallel when it enters the bottom of the target box receiving slot 4.

[0119] The target box receiving slot 4 is positioned directly below the discharge port 2 and is tilted downwards so that the target box 3 can slide to the inlet of the transfer pipe 5 by gravity alone. For example, Figure 1 As shown, the target box receiving slot 4 is positioned lower than the unloading port 2. The lower end of the target box receiving slot 4 is connected to the transmission pipe 5. When the target box 3 falls into the target box receiving slot 4 by gravity, due to the shape of the target box receiving slot 4, the target box 3 will form a shape as shown in the diagram. Figure 1 As shown, the end of the target box 3 is directly opposite the inlet of the transmission tube 5.

[0120] like Figure 3 As shown, the target box 3 is cylindrical in shape with an arc-shaped end, which is more conducive to the transmission of the target box 3 in the transmission tube 5. Figure 4 and Figure 6 As shown, there is a gap at the end edges of two adjacent target boxes 3, which facilitates the insertion of the pin of the separator 7 between the two adjacent target boxes 3 to separate them.

[0121] One end of the transmission pipe 5 is connected to the target box receiving slot 4, and the other end is connected to the shielding box 6. The transmission pipe 5 needs to pass through the equipment area at the top of the heavy water reactor (this area has many devices and limited space). Its length is determined by the distance between the irradiation device 1 and the shielding box 6. The pipe shape and anchoring of the transmission pipe 5 are determined according to the conditions at the top of the heavy water reactor. The arrangement of the transmission pipe 5 is very flexible and suitable for the limited space at the top of the heavy water reactor. The transmission pipe 5 can be flexibly arranged with necessary bends and ascents according to the actual site conditions. The direction of the transmission pipe 5 is as follows: it starts from the target box receiving slot 4 and ends at the telescopic sleeve 10. The inner diameter of the telescopic sleeve 10 is slightly larger than the outer diameter of the transmission pipe 5. One end of the telescopic sleeve 10 is fitted over the outside of the transmission pipe 5, and the other end is inserted into the inside of the shielding box 6. The telescopic sleeve 10 can slide up and down along the transmission pipe 5.

[0122] The transmission pipe 5 enters the shielded box 6 from the top. (Example:) Figure 4 As shown, a section of transmission pipe 5 that enters the shielding box 6 is perpendicular to the shielding box 6. This section is called the vertical section, and multiple target boxes 3 can be temporarily placed in the vertical section.

[0123] A shield of a certain thickness is installed outside the vertical section of the transmission tube 5 to cause the short-half-life nuclides in the target box 3 to decay in a short time, thereby reducing the surface radioactivity level of the shielded transport container 14 and reducing the dose to the staff.

[0124] With the flexible arrangement of the transmission pipe 5, the shielding box 6 can be placed far away from the top of the heavy water stack, without being limited by space, which facilitates the arrangement of the shielding box 6 and the loading operation of the target box 3.

[0125] like Figure 4 and Figure 5 As shown, vacuum pump 8 and control valve assembly 9 are connected to the vertical section of transmission pipe 5 via pipelines. One end of control valve assembly 9 is connected to the outlet pipeline of vacuum pump 8, and the other end is connected to transmission pipe 5. Vacuum pump 8 generates a pressure lower than atmospheric pressure, and the negative pressure and flow rate are adjusted by control valve assembly 9.

[0126] like Figure 4 As shown, the control ball valve 11 is connected to the transmission pipe 5 at both ends. The vertical section of the transmission pipe 5 is a segmented structure. The upper and lower parts of the vertical section are connected by the control ball valve 11. The transmission pipe 5 above the control ball valve 11 (upper pipeline) is used to temporarily store multiple target boxes 3. The transmission pipe 5 below the control ball valve 11 (lower pipeline) is connected to the telescopic sleeve 10. A separator 7 is installed on the upper pipeline of the control ball valve 11, and the telescopic sleeve 10 is installed on the lower pipeline. When the control ball valve 11 is open, a channel with the same inner diameter as the transmission pipe 5 is formed inside the ball valve. The target box 3 enters the shielding box 6 through the ball valve. The valve core of the control ball valve 11 is a spherical structure with a through hole. When the ball valve is open, the axis of the through hole coincides with the axis of the ball valve, forming a channel. When the control ball valve 11 is closed, the transmission pipe 5 is sealed, which helps to create a negative pressure at the inlet of the transmission pipe 5, allowing the target box 3 to enter the vertical section of the transmission pipe 5.

[0127] The telescopic sleeve 10 is coaxial with the transmission pipe 5, fitted onto the outside of the transmission pipe 5, and extends into the shielding box 6. The telescopic sleeve 10 is driven by a telescopic cylinder 52, allowing it to move up and down relative to the transmission pipe 5. Normally, the telescopic sleeve 10 is in the raised position to avoid interference with the shielding transfer container 14. When loading the target box 3, the shielding transfer container 14 is first moved to the shielding transfer container hoisting position, and the telescopic sleeve 10 is lowered, aligned with the hole in the basket 18. The target box 3 falls into the hole in the basket 18 through the transmission pipe 5 and the telescopic sleeve 10. After the target box 3 is loaded, the telescopic sleeve 10 is raised again, allowing the shielding transfer container 14 to move to the inner cover operating position.

[0128] Preferably, the control ball valve 11 is an electrically controlled ball valve.

[0129] like Figure 4 and Figure 6 As shown, a nozzle is provided on the transmission pipe 5 located outside the shielding box 6, and the separator 7 is connected to the nozzle of the transmission pipe 5. The separator 7 is a cylinder with a pin, including a target separation cylinder 53 and a pin connected to the front end of the target separation cylinder 53. The pin enters the nozzle, and the target separation cylinder 53 drives the pin to move, allowing the pin to pass through the nozzle into and out of the transmission pipe 5. The nozzle is positioned near the upper part of the control ball valve 11 so that the separator 7 is installed near the upper part of the control ball valve 11. The pin of the separator 7 can be radially inserted into the transmission pipe 5 to separate two adjacent target boxes 3, enabling the sequential loading of the target boxes 3.

[0130] like Figure 4 As shown, counter 12 is mounted on the outside of transmission tube 5, located in the upper part of the vertical section of transmission tube 5. When target box 3 passes through counter 12, counting is triggered. Counter 12 is used to record the number of target boxes 3 entering the vertical section of transmission tube 5.

[0131] A negative pressure loop is formed by a vacuum pump 8, a control ball valve 11 (when closed), and a transmission pipe 5, creating a negative pressure zone at the inlet of the transmission pipe 5. The target box 3 falling from the discharge port 2 is drawn into the vertical section of the transmission pipe 5 by the combined action of its own kinetic energy and the negative pressure generated by the vacuum pump 8. The negative pressure loop established by this invention has a small volume (the inner diameter of the transmission pipe 5 is small, resulting in a smaller loop volume compared to the entire shielding box), and the negative pressure formation time is short, ensuring smooth drawing of the target box 3 into the transmission pipe 5. Multiple target boxes 3 can be placed in the vertical section of the transmission pipe 5, allowing for individual loading as needed, providing loading flexibility.

[0132] like Figure 4 , Figure 5 and Figure 7 As shown, the shielding box 6 is a lead-shielded enclosure with a rectangular structure. Two spaced-apart lifting holes and sleeve holes are located on the top of the enclosure. The lifting holes are closer to the front of the shielding box 6 than the sleeve holes. The distance between the lifting holes and sleeve holes can be adjusted according to actual needs. The inner cover lifting device 17 and the telescopic sleeve 10 pass through the lifting holes and sleeve holes respectively to enter the enclosure. An observation window 26 is installed at the rear of the shielding box 6. Operators can observe the operation of the equipment inside the enclosure through the observation window 26. A channel is located at the front of the shielding box 6, which is the passage for the conveyor belt 15 and the shielded transfer container 14 to enter and exit the shielding box 6. This channel is sealed by a shielding door 13. It should be noted that... Figure 4 The left side of the diagram shows the front end of the shielding box 6, and the right side shows the rear end of the shielding box 6.

[0133] Preferably, the channel is rectangular, and the observation window 26 is a lead glass observation window.

[0134] like Figure 4 , Figure 5 and Figure 7 As shown, the shielding box 6 is equipped with a conveyor belt 15, a turntable 29, an inner cover hanger 17, and a telescopic sleeve 10. The shielding box 6 is also equipped with auxiliary components such as a gamma probe 27, a camera 28, and lighting tools.

[0135] Conveyor belt 15 has three positions, namely the target box loading position (e.g., Figure 4 (as shown in the image), inner cover operation position (directly below inner cover lifting device 17), and shielded transfer container lifting position (as shown in the image). Figure 7(As shown in the diagram). When the conveyor belt 15 is in the target box loading position and the shielding door 13 is closed, the target boxes 3 are loaded one by one into the basket 18 of the shielded transfer container 14. When the conveyor belt 15 is in the inner cover operation position and the shielding door 13 is closed, the inner cover lifting device 17 is suspended by the crane 36 outside the shielding box 6 to lift or load the inner cover 16 of the shielded transfer container 14. When the conveyor belt 15 is in the shielded transfer container hoisting position and the shielding door 13 is open, the shielded transfer container 14 is hoisted into or out of the inner conveyor trolley 21 by an external crane.

[0136] like Figures 8 to 10 As shown, the conveyor belt 15 is a telescopic conveyor belt, which includes a frame 19, an intermediate conveying mechanism 20, an inner conveying trolley 21, a drive plate 22, a driven sprocket 23, a conveyor belt drive motor 24, a gearbox 25, rollers 54, guide wheels 55, and a shielding door 13.

[0137] The frame 19 is fixedly installed inside the shielding box 6. The frame 19 includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. One end of the outer side of one of the C-shaped channel steels is equipped with the gearbox 25 of the transmission belt 15 and the drive sprocket 48, and the other end is equipped with the driven sprocket 23. The chain 47 connects the drive sprocket 48 and the driven sprocket 23.

[0138] The intermediate conveying mechanism 20 includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. The distance between the two C-shaped channel steels of the intermediate conveying mechanism 20 is smaller than the distance between the two C-shaped channel steels of the frame 19, so that the intermediate conveying mechanism 20 can move between the two C-shaped channel steels of the frame 19. Two rollers 54 are installed at each end of the outer side of the C-shaped channel steel. One end of the intermediate conveying mechanism 20 is fixedly connected to the shielding door 13, and the other end is installed inside the C-shaped channel steel of the frame 19. The rollers 54 of the intermediate conveying mechanism 20 move inside the C-shaped channel steel of the frame 19. A stop is provided inside the C-shaped channel steel of the frame 19 to limit the travel of the intermediate conveying mechanism 20 and prevent the intermediate conveying mechanism 20 from detaching from the frame 19.

[0139] The inner conveyor trolley 21 includes two relatively parallel C-shaped channel steels and several transverse supports connecting the two C-shaped channel steels. The distance between the two C-shaped channel steels of the inner conveyor trolley 21 is smaller than the distance between the two C-shaped channel steels of the intermediate conveyor mechanism 20, so that the inner conveyor trolley 21 can move between the two C-shaped channel steels of the intermediate conveyor mechanism 20. Two guide wheels 55 are installed at each end of the outer side of the C-shaped channel steel of the inner conveyor trolley 21. The guide wheels 55 move along the inner side of the C-shaped channel steel of the intermediate conveyor mechanism 20. The two ends of the C-shaped channel steel of the intermediate conveyor mechanism 20 are closed, preventing the inner conveyor trolley 21 from detaching from the intermediate conveyor mechanism 20. A drive plate 22 is installed on the inner conveyor trolley 21. The drive plate 22 is a thin metal plate, one end of which is welded to the inner conveyor trolley 21, and the other end is suspended above the chain 47. It has two holes and is connected to the chain 47 by connectors (such as screws, bolts, etc.). The drive plate 22 transmits the driving force of the conveyor belt drive motor 24 to the inner conveyor trolley 21 via the chain 47, and realizes the opening and retraction of the conveyor belt 15. The chain 47 drives the inner conveyor trolley 21 to move back and forth along the frame 19 and the intermediate conveyor mechanism 20.

[0140] like Figures 8 to 10 As shown, the conveyor belt drive motor 24 is connected to the horizontal bevel gear 34 via a coupling 33. The horizontal bevel gear 34 is connected to the vertical bevel gear, and the vertical bevel gear is fixedly connected to the drive sprocket 48 on the same shaft. The drive sprocket 48 and the driven sprocket 23 are connected via a chain 47. The conveyor belt drive motor 24, the horizontal bevel gear 34, the vertical bevel gear, the drive sprocket 48, and the driven sprocket 23 are connected in a driving connection to drive the inner conveyor trolley 21 and the intermediate conveyor mechanism 20. The driven sprocket 23 is installed on the outer side of the frame 19, and the gearbox 25 containing the drive sprocket 48 is installed at the outer end of the frame 19. The chain 47 is fixedly connected to the drive plate 22.

[0141] Under the action of the chain 47, the inner layer conveying trolley 21 first moves along the intermediate conveying mechanism 20. When it moves to the end of the C-shaped channel steel of the intermediate conveying mechanism 20, the movement of the inner layer conveying trolley 21 in the intermediate conveying mechanism 20 is restricted. The inner layer conveying trolley 21 drives the intermediate conveying mechanism 20 to move together along the frame 19.

[0142] like Figure 7 As shown, a turntable 29 is fixedly installed on the inner conveyor trolley 21, and a shielded transfer container 14 is placed on the turntable 29. A manual operation hole is provided on the top of the shielded box 6, which is sealed by a plug 49. The conveyor belt drive motor 24 is located inside the shielded box 6. If the conveyor belt drive motor 24 malfunctions, the plug 49 on the top of the shielded box 6 can be removed, a rotating tool can be inserted through the manual operation hole, and the conveyor belt 15 can be manually driven to the inner cover operation position. The inner cover 16 can then be installed, and the fault can be resolved.

[0143] like Figure 3 , Figure 5 , Figure 7 , Figures 11 to 13 As shown, the turntable 29 is fixedly mounted on the inner conveyor trolley 21. The turntable 29 includes a gear disk 30 and a drive wheel 31, the diameter of which is larger than that of the drive wheel 31. One end of the cable chain 35 is fixedly mounted on the frame 19, and the other end is mounted on the turntable 29. The turntable drive motor 32 is connected to the drive shaft of the drive wheel 31. The cable and control line of the turntable drive motor 32 are driven by the cable chain 35, and the cable and control line pass through the cable groove of the cable chain 35. The cable chain 35 moves with the inner conveyor trolley 21. The cable chain 35 is composed of numerous unit chains that rotate freely between each other. The cable chain is used in reciprocating motion applications and can provide traction and protection for the built-in cables. To prevent cables from tangling, abrasion, pull-out, snagging, and scattering, cables are usually placed in cable cable chains to protect them, and the cables can also move back and forth with the cable chain. The shielded transfer container 14 is placed on the turntable 29. The turntable 29 drives the shielded transfer container 14 to rotate, so that the hole of the basket 18 is aligned with the outlet of the telescopic sleeve 10, and the target box 3 is accurately dropped into the hole of the basket 18.

[0144] like Figure 7 , Figures 11 to 13 As shown, the shielded transfer container 14 is a shielding body made of steel and lead materials. The shielded transfer container 14 is cylindrical in shape and has an internal cavity. The shielded transfer container 14 includes a cylindrical body 38, an inner cover 16, an outer cover 39, and a hanging basket 18.

[0145] The cylinder 38 includes a stepped cylindrical cavity, a basket 18 is placed inside the cylinder 38, a stepped inner cover 16 is installed on the upper part, and an outer cover 39 is installed on the outside of the inner cover 16.

[0146] The inner cover 16 is a stepped cylinder that fits into the upper part of the cavity of the cylinder 38. The top of the inner cover 16 has a stepped inner cover hole, the upper diameter of which is smaller than the lower diameter, and there is an arc-shaped structure at the connection between the upper and lower holes. The upper hole is used to insert the guide head 45 of the inner cover hanger 17. When the tapered body of the movable inner rod 43 of the inner cover hanger 17 is inserted downwards, the ball pin 46 moves from the inside to the outside of the spherical hole under the outward pressing force of the tapered body, locking the inner cover hanger 17 to the inner cover 16. When the tapered body of the movable inner rod 43 of the inner cover hanger 17 is lifted upwards, the ball pin 46 loses the outward pressing force of the tapered body and retracts under the action of the arc-shaped structure, thus disengaging the inner cover hanger 17 from the inner cover 16.

[0147] The basket 18 has a two-layer circular structure. The upper basket 51 has multiple through holes evenly arranged along the circumference, with a first control lever in the middle for downstream processes to extract and transfer the basket. The lower basket 50 has multiple deep holes evenly arranged along the circumference, with a second control lever in the middle for transfer. The upper and lower baskets 51 and 50 have the same size, number of holes, and distribution spacing, allowing the target box 3 to be placed vertically. The target box 3, when placed in the basket, protrudes a certain distance above the basket surface to facilitate gripping by downstream processes; this distance can be selected according to the downstream process. The lower basket 50 can be placed alone in the shielded transfer container 14, or two baskets can be stacked together and placed in the shielded transfer container 14, giving the basket 18 the flexibility to load the target box 3.

[0148] The outer cover 39 is a disc with a central opening, which is bolted to the cylinder 38 to restrict the axial movement of the inner cover 16 and the basket 18, facilitating the transportation of the shielded transfer container 14 and mitigating the consequences of an accident where the shielded transfer container 14 tipped over.

[0149] The shielded transfer container 14 is placed on the turntable 29, and the rotation angle is precisely positioned by adding existing control components such as shaft encoders. The turntable drive motor 32 is controlled by the shaft encoder and PLC. By comparing the difference between the actual position and the preset position of the turntable 29, the turntable drive motor 32 drives the turntable 29 to be precisely positioned to the preset position.

[0150] like Figures 14 to 17 As shown, the inner cover lifting tool 17 is a specially designed tool for gripping, securing, and releasing the inner cover 16 of the shielded transport container 14. The inner cover lifting tool 17 includes a lifting ring 40, a locking pin 41, an operating lever 42, a movable inner rod 43, an outer cylinder 44, a guide head 45, and a ball pin 46. Figure 7 As shown, the inner cover lifting device 17 is lifted by the crane 36 outside the shielding box 6.

[0151] The outer cylinder 44 is a cylindrical steel tube with a threaded cap at the top and a flange structure at the bottom. The lifting ring 40 is threadedly connected to the cap. The flange of the guide head 45 is bolted to the flange at the bottom of the outer cylinder 44. A C-groove is provided at the top of the outer cylinder 44, through which the operating lever 42 enters the outer cylinder 44 and connects to the movable inner rod 43. When the operating lever 42 moves the movable inner rod 43 upwards to the leftmost position above the C-groove, the ball pin 46 is retracted and inserted into the locking pin 41, keeping the inner cover lifting device 17 in the unlocked state. When the operating lever 42 moves the movable inner rod 43 downwards to the leftmost position below the C-groove, the ball pin 46 is extended and inserted into the locking pin 41, keeping the inner cover lifting device 17 in the locked state. It should be noted that the connection between the operating lever 42 and the movable inner rod 43 is as follows: Figure 15 As shown, another rod (on the right side) is connected to the outer cylinder 44, which acts as a handrail to facilitate manual operation of the control lever 42 and the locking pin 41.

[0152] The guide head 45 has a through hole in the middle, a flange mechanism at the upper end, and a tapered structure at the lower end. Three spherical holes are formed circumferentially in the middle section of the guide head 45, each capable of accommodating a ball pin 46. These three spherical holes are, for example, evenly distributed circumferentially. The size of the spherical holes is designed to ensure that the ball pin 46 engages with the inner hole of the inner cover 16, while also preventing the ball pin 46 from disengaging outwards. Specifically, the outlet size of the spherical hole is small to prevent the ball pin 46 from completely disengaging; only a portion of the ball pin 46 can extend outwards. The ball pin 46 can move within the spherical holes but will not disengage. When the movable inner rod 43 moves downwards, the three ball pins 46 extend under the force of the tapered body at the lower end of the movable inner rod 43. When the movable inner rod 43 moves upwards, the force of the tapered body at the lower end of the movable inner rod 43 disappears, and the three ball pins 46 can retract back into the through hole in the middle of the guide head 45.

[0153] The movable inner rod 43 is located inside the outer cylinder 44. The lower end of the movable inner rod 43 has a certain taper, and the upper end is connected to the operating rod 42. The movable inner rod 43 is installed inside the outer cylinder 44, with the tapered end ( Figure 16 The lower end of the inner rod is inserted into the guide head 45, and the control lever 42 drives the movable inner rod 43 to move along the C-shaped groove of the outer cylinder 44.

[0154] When the lever 42 moves upward, the ball pin 46 of the guide head 45 retracts. When the lever 42 moves downward, the ball pin 46 of the guide head 45 extends. The guide head 45 is inserted into the hole of the inner cover 16, and the extension and retraction of the ball pin 46 locks and releases the inner cover hanger 17 from the inner cover 16.

[0155] like Figure 4 and Figure 7 As shown, the gamma probe 27 is installed inside the shielding box 6 to detect the gamma dose level of the box. Only when the gamma dose is below a certain level is the shielding door 13 allowed to be opened to prevent personnel from receiving accidental radiation.

[0156] Camera 28 is installed inside the shielded enclosure 6 and is used to monitor the operation of the equipment inside the enclosure via a remote terminal. The number and installation location of cameras 28 can be selected according to the actual situation.

[0157] In addition, the present invention also provides a method for transporting a target box after heavy water reactor irradiation, comprising the following steps:

[0158] Step 1: Establish a negative pressure within the transfer tube 5, and transfer the target box 3 from the target box receiving slot 4 to the vertical section of the transfer tube 5 using a negative pressure method. In Step 1, storing the target box 3 in the vertical section of the transfer tube 5 for a period of time allows the extremely short half-life nuclide in the target box 3 to decay, reducing the dose level of the target box 3 loading operation and the shielded transport container 14.

[0159] Step 2: Open the shielding door 13, place the shielding transfer container 14 on the turntable 29 of the inner conveyor trolley 21, and remove the outer cover 39 of the shielding transfer container 14.

[0160] Step 3: The inner layer conveyor trolley 21 moves the shielding transfer container 14 to the inner cover operation position, the inner cover lifting device 17 lifts the inner cover 16 of the shielding transfer container 14, the inner layer conveyor trolley 21 moves the shielding transfer container 14 to the target box loading position, and the shielding door 13 closes.

[0161] Step 4: Insert the target box 3 in the vertical section of the transmission pipe 5 into the hole of the basket in the shielded transfer container 14 in the shielded box 6.

[0162] Step 5: Install the inner cover 16 onto the top of the shielded transfer container 14 in the shielded box 6;

[0163] Step 6: Transport the shielded transfer container 14 out of the shielded box 6 via the conveyor belt 15, and install the outer cover 39 on the shielded transfer container 14.

[0164] Step 7: Transport the shielded transport container 14 to the designated location.

[0165] Specifically, the implementation process of the target box transfer method after heavy water reactor irradiation provided by the present invention is as follows:

[0166] Close the control ball valve 11, retract the pin of the separator 7, start the vacuum pump 8, and as the trolley moves in the production channel, the target boxes 3 are sucked into the vertical section of the transfer pipe 5 one by one. The counter 12 counts the target boxes 3 that enter the vertical section of the transfer pipe 5.

[0167] The conveyor belt drive motor 24 moves the inner layer conveyor trolley 21 to the hoisting position of the shielded transfer container, at which time the shielding door 13 is in the open state.

[0168] The factory crane places the shielded transfer container 14 onto the turntable 29 of the inner conveyor trolley 21. The outer cover 39 of the shielded transfer container 14 is then removed.

[0169] The conveyor belt drive motor 24 moves the inner layer conveyor trolley 21 to the inner cover operation position. The crane 36 inserts the inner cover lifting device 17 into the hole of the inner cover 16. After it is in place, the inner cover lifting device 17 is locked to the inner cover 16, the locking pin 41 is inserted, and the inner cover 16 is lifted away from the shielded transfer container 14 to the preset height.

[0170] The conveyor belt drive motor 24 moves the inner layer conveyor trolley 21 to the target box loading position, and the shielding door 13 closes.

[0171] The telescopic cylinder 52 drives the telescopic sleeve 10 to a preset position above the suspended platform.

[0172] The turntable drive motor 32 drives the turntable 29, which in turn causes the shielded transfer container 14 placed on the drive turntable 29 to rotate together, so that one hole of the basket 18 is axially aligned with the telescopic sleeve 10.

[0173] The target separation cylinder 53 of the separator 7 drives the pin to insert between the two target boxes 3.

[0174] Open the control ball valve 11, and a target box 3 falls into the basket 18 hole by gravity.

[0175] Close the control ball valve 11, retract the pin of the separator 7, the next target box 3 falls onto the control ball valve 11, and then insert the pin of the separator 7.

[0176] The turntable drive motor 32 rotates the shielded transfer container 14 to the next empty position of the basket 18, aligning it with the telescopic sleeve 10.

[0177] Repeat the above steps to insert all target boxes 3 into the holes of the basket 18.

[0178] The telescopic cylinder 52 drives the telescopic sleeve 10 to the preset position.

[0179] The conveyor belt drive motor 24 moves the inner layer conveyor trolley 21 to the inner cover operation position.

[0180] Operate the inner cover lifting device 17 to place the inner cover 16 onto the shielded transport container 14. Unlock the inner cover lifting device 17 and raise it to the preset position.

[0181] The conveyor belt drive motor 24 moves the inner layer conveyor trolley 21 to the shielding container hoisting position.

[0182] The operator manually installs the outer cover 39 of the shielded transfer container 14.

[0183] The shielded transfer container 14 was transported to the designated location in the factory using a factory crane.

[0184] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A target box transfer device after heavy water reactor irradiation, characterized in that, include: A transfer pipe (5) for receiving target boxes (3) and passing through the top of the heavy water stack has a vertical section. A portion of the vertical section is inserted into a shielded box (6). A separator (7) is provided on the vertical section to allow the target boxes (3) to enter the shielded box (6) one by one. A vacuum pump (8) is provided on the transfer pipe (5) to create a negative pressure in the transfer pipe (5) to draw the target boxes (3) into the vertical section. A control ball valve (11) is provided on the transfer pipe (5) below the installation position of the separator (7). The control ball valve (11) connects the upper and lower parts of the vertical section into one unit. The control ball valve (11) has the same inner diameter as the transfer pipe (5). When the control ball valve (11) is opened, the inside of the control ball valve (11) forms a channel with the transmission pipe (5) so that the target box (3) enters the shielding box (6) through the control ball valve (11); when the control ball valve (11) is closed, the transmission pipe (5) is sealed to form a negative pressure at the entrance of the transmission pipe (5) so that the target box (3) enters the vertical section. The transmission pipe (5) is covered with a telescopic sleeve (10), which extends into the shielding box (6). The telescopic sleeve (10) is driven by a telescopic cylinder (52) to move the telescopic sleeve (10) up and down relative to the transmission pipe (5). A shielded transport container (14) for loading the target box (3), with the inner cover (16) of the shielded transport container (14) installed or removed by an inner cover lifter (17) mounted on the shielded box (6); and A conveyor belt (15) is used to transport the shielded transfer container (14) into or out of the shielded box (6). The conveyor belt (15) includes a frame (19), an intermediate conveying mechanism (20), and an inner layer conveying trolley (21). The inner layer conveying trolley (21) is slidably disposed on the intermediate conveying mechanism (20), and the intermediate conveying mechanism (20) is slidably disposed on the frame (19). The conveyor belt (15) is provided with a target box loading position, an inner cover operation position, and a shielded transfer container hoisting position. When the target box is in the loading position, the shielding door (13) is closed, and the target box (3) is loaded into the shielding transfer container (14) one by one; when the conveyor belt (15) is in the inner cover operation position, the shielding door (13) is closed, and the inner cover is lifted off or loaded into the inner cover (16) using the inner cover lifting tool (17); when the conveyor belt (15) is in the shielding transfer container hoisting position, the shielding door (13) is open, and the shielding transfer container (14) is hoisted in or off by an external crane.

2. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The separator (7) includes a target separation cylinder (53) and a pin connected to the front end of the target separation cylinder (53), and the target separation cylinder (53) drives the pin to move.

3. The target box transfer device after heavy water reactor irradiation according to claim 2, characterized in that, The vertical section is provided with a nozzle, and the pin enters and exits the transmission pipe (5) through the nozzle.

4. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The vacuum pump (8) is connected to the vertical section via a pipeline, and a control valve group (9) is provided on the pipeline.

5. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The vertical section is inserted vertically into the shielding box (6).

6. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, A counter (12) is fitted on the vertical section to record the number of target boxes (3) entering the vertical section.

7. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The inlet of the transmission tube (5) is connected to a target box receiving slot (4), which is used to receive the target box (3) falling from the discharge port (2) of the irradiation device (1).

8. The target box transfer device after heavy water reactor irradiation according to claim 1 or 7, characterized in that, The target box (3) is cylindrical in shape with arc-shaped ends.

9. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The shielding box (6) is a box with lead shielding. The top has two lifting holes and sleeve holes spaced a certain distance apart. The front end has a channel to allow the conveyor belt (15) to enter and exit the shielding box (6). The rear end has a hole to install an observation window (26).

10. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The shielded transfer container (14) includes the inner cover (16), the basket (18) and the cylinder (38), with the basket (18) disposed in the cylinder (38).

11. The target box transfer device after heavy water reactor irradiation according to claim 10, characterized in that, The cylinder (38) has a stepped cylindrical cavity, and the inner cover (16) is a stepped cylinder, which is fitted and installed with the upper part of the stepped cylindrical cavity.

12. The target box transfer device after heavy water reactor irradiation according to claim 10 or 11, characterized in that, The top of the inner cover (16) is provided with an inner cover hole with a stepped shape. The diameter of the upper hole of the inner cover hole is smaller than that of the lower hole. The connection between the upper hole and the lower hole is provided with an arc-shaped structure.

13. The target box transfer device after heavy water reactor irradiation according to claim 10, characterized in that, The suspended basket (18) is a two-layer circular structure, including an upper suspended basket (51) and a lower suspended basket (50). The upper suspended basket (51) has multiple through holes evenly arranged along the circumference, and the lower suspended basket (50) has multiple deep holes evenly arranged along the circumference. The upper suspended basket (51) and the lower suspended basket (50) have the same size, number of holes and distribution spacing.

14. The target box transfer device after heavy water reactor irradiation according to claim 13, characterized in that, The upper basket (51) is provided with a first control lever in the middle, which is used for downstream processes to extract and transfer the upper basket (51). The lower basket (50) is provided with a second control lever in the middle, which is used for downstream processes to extract and transfer the lower basket (50).

15. The target box transfer device after heavy water reactor irradiation according to claim 10, characterized in that, The shielded transfer container (14) also includes an outer cover (39), which is a disc with a central opening, connected to the cylinder (38), and restricts the axial movement of the inner cover (16) and the basket (18).

16. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The frame (19) is installed inside the shielding box (6) and includes two C-shaped channel steels arranged in parallel and several transverse supports connected between the two C-shaped channel steels. One of the outer ends of one of the C-shaped channel steels is equipped with a transmission belt drive motor (24) and a gearbox (25), and the other end is equipped with a driven sprocket (23). The driven sprocket (23) is connected to the drive sprocket (48) inside the gearbox (25) through a chain (47).

17. The target box transfer device after heavy water reactor irradiation according to claim 16, characterized in that, The transmission belt drive motor (24) is connected to the horizontal bevel gear (34) in the gearbox (25) via a coupling (33). The drive sprocket (48) and the vertical bevel gear are mounted on the same shaft, and the vertical bevel gear meshes with the horizontal bevel gear (34).

18. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The intermediate conveying mechanism (20) includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. Rollers (54) are installed at both ends of the outer side of the C-shaped channel steels of the intermediate conveying mechanism (20). One end of the intermediate conveying mechanism (20) is fixedly connected to the shielding door (13), and the other end is installed in the C-shaped channel steel of the frame (19). The inner side of the C-shaped channel steel of the frame (19) is provided with a stop block to limit the movement stroke of the intermediate conveying mechanism (20) and prevent the intermediate conveying mechanism (20) from detaching from the frame (19).

19. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The inner conveying trolley (21) includes two relatively parallel C-shaped channel steels and several transverse supports connected between the two C-shaped channel steels. Guide wheels (55) are installed at both ends of the outer side of the C-shaped channel steels of the inner conveying trolley (21). The guide wheels (55) move along the inner side of the C-shaped channel steels of the intermediate conveying mechanism (20). The two ends of the C-shaped channel steels of the intermediate conveying mechanism (20) are closed, restricting the inner conveying trolley (21) from leaving the intermediate conveying mechanism (20).

20. The target box transfer device after heavy water reactor irradiation according to claim 19, characterized in that, A drive plate (22) is installed on the inner layer conveying trolley (21). One end of the drive plate (22) is welded to the inner layer conveying trolley (21), and the other end is located above the chain (47). The drive plate (22) and the chain (47) are connected by a connector.

21. The target box transfer device after heavy water reactor irradiation according to any one of claims 16 to 20, characterized in that, The inner layer conveying trolley (21) is equipped with a turntable (29), which carries and rotates the shielded transfer container (14).

22. The target box transfer device after heavy water reactor irradiation according to claim 21, characterized in that, The turntable (29) includes a gear disk (30), a drive wheel (31), and a turntable drive motor (32). The shielded transfer container (14) is placed on the gear disk (30). The turntable drive motor (32) drives the drive wheel (31), and the drive wheel (31) drives the gear disk (30) to rotate.

23. The target box transfer device after heavy water reactor irradiation according to claim 22, characterized in that, The conveyor belt (15) is provided with a drag chain (35), one end of which is fixedly installed on the frame (19), and the other end is installed on the turntable (29).

24. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The shielding box (6) is provided with a manual operation hole, and a removable plug (49) is installed on the manual operation hole. The rotating tool passes through the manual operation hole and drives the conveyor belt (15) to the inner cover operation position by manual drive.

25. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The inner cover lifting device (17) includes a locking pin (41), a control lever (42), a movable inner rod (43), an outer cylinder (44), a guide head (45), and a ball pin (46). The movable inner rod (43) is located inside the outer cylinder (44). A C-shaped groove is provided on the outer cylinder (44). The control lever (42) is connected to the movable inner rod (43) through the C-shaped groove. A tapered body is provided at the lower end of the movable inner rod (43). The tapered body pushes the ball pin (46) to extend out of the guide head (45).

26. The target box transfer device after heavy water reactor irradiation according to claim 25, characterized in that, The guide head (45) has three spherical holes along the circumferential radial direction in the middle section, and the three ball pins (46) are located in the spherical holes.

27. The target box transfer device after heavy water reactor irradiation according to claim 25, characterized in that, The inner cover lifting device (17) also includes a lifting ring (40), which is threadedly connected to the upper end of the outer cylinder (44).

28. The target box transfer device after heavy water reactor irradiation according to claim 25, characterized in that, The inner cover lifting device (17) is lifted by a crane (36) outside the shielding box (6).

29. The target box transfer device after heavy water reactor irradiation according to claim 1, characterized in that, The shielding box (6) is equipped with a gamma probe (27) and a camera (28).

30. A method for transporting a target box after heavy water reactor irradiation, characterized in that, The method, employing the apparatus as described in any one of claims 1 to 29, comprises: A negative pressure environment is established inside the transmission tube, and the target box is sequentially sucked into the vertical section of the transmission tube from the inlet of the transmission tube. The target boxes in the vertical section are sequentially inserted into the designated positions inside the shielded transport container in the shielded box; After the shielded transport container is filled, an inner cover is installed inside the shielded box, and an outer cover is installed outside the shielded box.

31. The target box transfer method after heavy water reactor irradiation according to claim 30, characterized in that, The transmission method specifically includes the following steps: Step 1: Establish negative pressure in the transmission tube and transfer the target box from the target box receiving slot to the vertical section using negative pressure. Step 2: Open the shielding door, place the shielded transfer container on the turntable of the inner conveyor trolley, and remove the outer cover; Step 3: The inner layer conveying trolley moves the shielding transfer container to the inner cover operation position, the inner cover tool lifts the inner cover, the inner layer conveying trolley moves the shielding transfer container to the target box loading position, and the shielding door is closed; Step 4: Insert the target boxes in the vertical section into the holes of the basket inside the shielded transfer container in sequence; Step 5: Install the inner cover onto the top of the shielded transport container inside the shielded box; Step 6: Transport the shielded transfer container out of the shielded box via a conveyor belt, and install the outer cover on the shielded transfer container; Step 7: Transport the shielded transport container to the designated location.

32. The target box transfer method after heavy water reactor irradiation according to claim 31, characterized in that, Step 1 includes: Close the control ball valve, retract the separator pin, and start the vacuum pump; As the trolley moves within the production channel, the target boxes are sucked into the vertical section one by one, and a counter counts the target boxes entering the vertical section.

33. The target box transfer method after heavy water reactor irradiation according to claim 31, characterized in that, Step 2 includes: The conveyor belt drive motor moves the inner layer conveyor trolley to the hoisting position of the shielded transfer container; The factory crane places the shielded transfer container on the turntable of the inner conveyor trolley and removes the outer cover.

34. The target box transfer method after heavy water reactor irradiation according to claim 31, characterized in that, Step 3 includes: The conveyor belt drive motor moves the inner layer conveying trolley to the inner cover operation position. The crane inserts the inner cover tool into the hole of the inner cover. After it is in place, the inner cover lifting tool is locked to the inner cover, the locking pin is inserted, and the inner cover is lifted away from the shielded transfer container to a preset height. The conveyor belt drive motor moves the inner layer conveyor trolley to the target box loading position and closes the shielding door.

35. The target box transfer method after heavy water reactor irradiation according to claim 31, characterized in that, Step 4 includes: The telescopic cylinder drives the telescopic sleeve to descend to a preset position above the suspended basket; The turntable drive motor rotates the shielded transfer container, axially aligning one hole of the suspended basket with the telescopic sleeve; The target separation cylinder drives the pin to insert between the two target boxes; Open the control ball valve, and the target box falls into the basket hole by gravity; Close the control ball valve, retract the pin, the next target box falls onto the control ball valve, and then insert the pin again; The turntable drive motor rotates the shielded transfer container to the next empty position of the suspended basket, aligning it with the telescopic sleeve; Repeat the above steps to insert all the target boxes into the holes of the basket.

36. The method for transferring a target box after heavy water reactor irradiation according to claim 31, characterized in that, Step 5 includes: The telescopic cylinder drives the telescopic sleeve to lift it to the preset position. The conveyor belt drive motor moves the inner layer conveying trolley to the inner cover operation position; Operate the inner cover lifting tool to install the inner cover onto the shielded transfer container, unlock the inner cover lifting tool, and lift it to the preset position.

37. The method for transferring a target box after heavy water reactor irradiation according to claim 31, characterized in that, Step 6 includes: The conveyor belt drive motor moves the inner layer conveyor trolley to the shielding container hoisting position; The outer cover is installed on the shielded transport container.

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