Device for reducing the dose of operating maintenance of an isotopic production target station

Abstract

The application discloses a device for reducing operation and maintenance dose of an isotope production target station, comprising a collimator and a proton trap, wherein a graphite protection layer is arranged around the end face of the collimator which is directly irradiated by a beam and the guiding slope in the proton trap through which the beam passes, for absorbing radiation and reducing equipment activation; a quick chuck type structure is arranged outside the collimator and the proton trap, so that quick installation and disassembly of the equipment are realized; and movable lead shielding devices, namely A and B lead shielding devices, are further arranged outside the collimator and the proton trap, wherein the lead shielding devices are driven by a driving mechanism and can move to the two sides of the collimator and the proton trap during maintenance, so as to provide local radiation shielding; the application breaks through the depth coupling of the technologies in the fields of material science, mechanical design and radiation protection engineering, solves the problems of high radiation dose and serious activation in the prior art, and solves the problems of inconvenient maintenance operation, low efficiency and environmental radiation influence.

Description

Technical Field

[0001] This invention belongs to the field of nuclear technology application / radioactive isotope production, and particularly relates to a device for reducing the operating and maintenance dose of an isotope production target station. Background Technology

[0002] Isotope production target stations are crucial devices for preparing radioactive isotopes, primarily consisting of systems for beam transmission, collimation, energy attenuation, and the target itself. Under prolonged irradiation by high-energy particle beams (such as proton beams), the metal structural components within the target station (especially copper components, such as collimators and proton traps) undergo significant activation, producing a series of long-half-lived radionuclides (e.g., Co-58, Co-57, and Zn-65 generated after copper activation). These activated components continue to release strong radiation during shutdown maintenance, posing significant challenges to equipment maintenance. For example, under proton beam intensities of approximately 5 μA, the surface dose rate of an activated copper collimator can reach around 100 mSv / h; the surface dose rate of an activated proton trap without graphite protection can also reach around 43 mSv / h. Maintenance personnel working in such high-dose radiation environments face serious health risks, requiring strict radiation protection measures and severely limited working hours, leading to a significant reduction in maintenance efficiency. Furthermore, in existing high-energy isotope production target stations, highly activated components (such as collimators and proton traps) and vacuum boxes are mostly connected by bolts. During maintenance, all bolts must be removed to remove the relevant components, making the operation process cumbersome. In a high-radiation environment, this significantly prolongs the exposure time of personnel, further increasing the radiation risk.

[0003] In summary, the main technical problems currently existing in the maintenance of isotope production target stations are as follows:

[0004] 1. High radiation dose and severe activation: Long half-life nuclides generated by direct beam bombardment of metal components cause continuous high activation of the equipment, resulting in extremely high radiation field intensity during maintenance;

[0005] 2. Inconvenient maintenance and low efficiency: Traditional bolt connection methods are complicated to disassemble, time-consuming, and increase the exposure time of personnel in the radiation environment;

[0006] 3. Environmental radiation impact: The presence of long half-life nuclides leads to an increase in air dose, further increasing the risk of radiation exposure for maintenance personnel.

[0007] The aforementioned problems severely restrict the maintenance safety and operational efficiency of isotope production target stations, and there is an urgent need to develop new technical solutions that can significantly reduce maintenance dosage, simplify maintenance procedures, and improve overall safety. Summary of the Invention

[0008] This invention addresses the problems existing in the prior art by proposing a device for reducing the operating and maintenance dose of isotope production target stations. The purpose is to solve the problems of high radiation dose, severe activation, inconvenient and inefficient maintenance and operation, and environmental radiation impact of the prior art.

[0009] To solve its technical problem, the present invention designs the following technical solution:

[0010] A device for reducing operational and maintenance doses at an isotope production target station includes a collimator and a proton trap. The device is characterized by: graphite protective layers provided on the end face of the collimator directly irradiated by the beam, and around the guide ramp through which the beam passes inside the proton trap, to absorb radiation and reduce equipment activation; quick-connect chuck structures are respectively configured on the exterior of the collimator and the proton trap for rapid installation and disassembly; a pair of movable lead shielding devices, designated A and B, are also provided on the exterior of the collimator and the proton trap, driven by a drive mechanism, enabling them to move towards each other to both sides of the collimator and the proton trap during maintenance, providing localized radiation shielding; the collimator forms four end faces (top, bottom, left, and right) along the beam envelope for beam confinement.

[0011] Furthermore, the main body material of the collimator and proton trap is oxygen-free copper.

[0012] Furthermore, the provision of a graphite protective layer on the end face of the collimator that is directly irradiated by the beam means that a graphite protective layer is provided on the four end faces of the collimator that trap the beam.

[0013] Furthermore, the provision of a graphite protective layer around the guide ramp through which the proton trap beam passes specifically involves setting a graphite protective layer within a defined height and width range above the front baffle, the rear baffle, and the guide ramp between the front and rear baffles where the beam passes through the guide ramp.

[0014] Furthermore, the provision of a graphite protective layer within a specified height range above the guide ramp at the front baffle, rear baffle, and between the front and rear baffles of the beam means that: the height and width of the graphite protective layer at the front baffle match the coverage area of ​​the beam when it passes the front baffle; the height and width of the graphite protective layer at the rear baffle match the coverage area of ​​the beam when it passes the rear baffle; and the height and width of the graphite protective layer within a specified height and width range above the guide ramp match the coverage area of ​​the beam when it passes the guide ramp.

[0015] Furthermore, the graphite protective layer is fixed to the substrate of the collimator or proton trap by welding, and the surface of the graphite protective layer welded to the substrate is metallized.

[0016] Furthermore, the lead shielding device A and lead shielding device B are each equipped with their own support frame, casters, lead plates, and support baffles on the lead plates; the support frame is door frame shaped; the lead plates are embedded in the upper part of the support frame, and the height and width of the lead plates match the height and width of the radiation areas of the collimator and proton trap; each lead plate is equipped with radiation-proof baffles to protect the human head and sides; the lead plates are also provided with radiation-proof transparent observation windows and hand-operated holes; the radiation-proof transparent observation windows are used for operator observation, and the hand-operated holes are used for reaching into the holes for operation; their respective drive mechanisms are connected to lead shielding device A and lead shielding device B respectively, and are used to drive them to the working position or to withdraw; their respective mobile chassis are respectively set at the bottom of lead shielding device A and lead shielding device B, and are used to support and move the devices.

[0017] Furthermore, the drive mechanism includes a DC brake motor with a power-off self-locking function.

[0018] Advantages and effects of the present invention

[0019] I. Solving the problem of "high radiation dose and severe activation". By pre-applying a graphite protective layer to easily activated areas, the generation of long-half-life radionuclides can be significantly reduced, thereby lowering the radiation field intensity during equipment shutdown and maintenance, and providing a safer working environment for personnel. As a low atomic number material, graphite can effectively absorb secondary radiation generated when high-energy particle beams collide with metal components and significantly reduce the degree of activation of metal materials.

[0020] II. Addressing the issues of "inconvenient and inefficient maintenance operations." The collimator and proton trap are each equipped with a quick-connect chuck structure and a pair of movable lead shielding devices (A and B), controlled by a drive mechanism. During maintenance, these devices can move towards each other to form localized shielding on both sides of critical components. The quick-connect chucks replace traditional bolt connections, greatly simplifying the disassembly and assembly process, shortening personnel exposure time in the radiation environment, and improving maintenance efficiency. The movable lead shielding can provide close-range, directional shielding for highly active components, effectively reducing the radiation dose in the maintenance area, ensuring personnel safety, and not affecting operations in other areas.

[0021] III. Mitigating the Impact of Environmental Radiation: This involves the combined application of the aforementioned graphite protective layer and movable lead shielding device. By reducing equipment activation (reducing radiation at the source) and providing localized shielding during maintenance (protection during operation), the spread of radioactivity and the intensity of the radiation field are reduced. This not only directly protects maintenance personnel but also helps control long-term radiation levels in the working environment, mitigating the environmental impact.

[0022] In summary, this invention, by adding a graphite protective layer to suppress activation and combining a quick-connect chuck structure with a movable lead shielding device, achieves rapid maintenance and local shielding, systematically solving the radiation safety and operational efficiency problems in the maintenance of isotope production target stations, and achieving significant effects in reducing radiation dose, improving maintenance efficiency, and enhancing operational safety. Attached Figure Description

[0023] Figure 1 Top view (left) and cross-sectional view (right) of dose distribution after activation of the collimator copper layer (before the graphite layer is added);

[0024] Figure 2 The top view (left) and cross-sectional view (right) of the dose distribution after adding graphite activation to the copper layer of the collimator according to the present invention.

[0025] Figure 3 The location where the graphite protective layer is added to the copper block of the proton trap in this invention;

[0026] Figure 4a This is a three-dimensional model diagram of the target station for the present invention (including collimator and proton trap);

[0027] Figure 4b This is a schematic diagram of the quick-release chain clamp and hoisting structure of the present invention;

[0028] Figure 5 This is a side view of the target station produced by the present invention;

[0029] Figure 6 This is an application effect diagram of a pair of movable lead shielding devices of the present invention; Detailed Implementation

[0030] Innovation of this invention

[0031] This invention innovatively integrates technologies from three fields: materials science (graphite protective layer), mechanical design (quick-connect chuck), and radiation protection engineering (movable lead shielding), forming a self-reinforcing, closed-loop optimized protection system. The core innovation system is described below:

[0032] First layer (root layer): Graphite protective layer – transforming the "activation source" into an "energy-dissipating buffer layer".

[0033] It's not just about "shielding," but also about "energy conversion and dispersion." By leveraging its low atomic number, the impact energy of the high-energy proton beam is preferentially converted into low-energy activation energy in the graphite itself (resulting in products with short half-lives and low hazard), and some particles are scattered. Essentially, it replaces the long-lived radioactive "contaminant" with a short-lived, easily managed "consumable." This design changes the equipment's passive approach to beam current, achieving "active energy management" and creating a fundamental safety prerequisite for all subsequent operations.

[0034] Second layer (process layer): Quick-connect chuck structure – minimizing the "maintenance window":

[0035] By reducing background radiation through graphite layers, the most time-consuming mechanical connection / separation process is revolutionaryly accelerated. Its innovation lies not only in its speed but also in its deep integration with radiation safety logic: in a radiation field, time is dose. It ensures that the duration of human exposure is reduced from "hours" to "minutes," transforming uncontrollable cumulative dose risk into controllable, extremely short-term time risk.

[0036] The third layer (on-site layer): Portable lead shielding device – providing a "customized" personal protective fortress: After optimizing the "environment" and "time" in the first two layers, this device addresses the final spatial risks. Like a movable "protective shield," it establishes a temporary, high-density shield between personnel and residual radiation sources. The design of observation windows and hand-held ports allows for micro-environmental safety control, enabling "shielding without shielding the field of vision and operation." It embodies the modern radiation protection concept of "dynamic, precise, and reconfigurable," replacing bulky monolithic shielding with extremely high flexibility.

[0037] Design principle of the invention

[0038] I. Application of Graphite Protective Layer for Source Activation Suppression: To address the issue that direct bombardment of metal components (such as collimators and proton traps) by high-energy beams can lead to severe activation and the production of long-half-life radionuclides, a graphite protective layer is applied to the direct beam irradiation surfaces of these key components (such as the collimator beam-limiting end face, proton trap baffle, and ramp). As a low atomic number material, graphite produces activation products with low energy and short half-lives after irradiation. This protective layer effectively absorbs some of the radiation energy, blocks and scatters secondary particles, thereby significantly reducing the activation level of the underlying copper main component and reducing long-lived radioactivity at the source.

[0039] II. Quick-connect chuck structure for rapid installation and disassembly: Addressing the issue of time-consuming disassembly of traditional bolted connections in radiation environments, significantly increasing personnel exposure time, a quick-connect chuck external connection structure is configured for the collimator and proton trap. This structure allows for rapid assembly and disassembly without tools or with simple operations. During maintenance, it greatly reduces equipment disassembly and installation time, thereby directly reducing the exposure time of maintenance personnel in the radiation field and improving work efficiency.

[0040] III. Deployment of Movable Lead Shielding Devices for Local Radiation Shielding: To address the issue of potentially high doses in localized areas during maintenance even with graphite layer suppression, a pair of movable lead shielding devices (A and B) controlled by a drive mechanism are installed externally on the equipment. During maintenance, the two devices can move towards each other to either side of the equipment, forming a locally enclosed, highly shielded area. Lead's high density provides excellent shielding against gamma rays and other radiation. This targeted, adjustable shielding method effectively blocks radiation from activated components, providing maintenance personnel with an additional dynamic protective barrier and further reducing operational dose.

[0041] IV. Integrated Design of Shielding Device for Optimized Maintenance: Addressing the need to simultaneously consider the practicality, safety, and ease of operation of the shielding device, the lead shielding device adopts an integrated design, including a support frame, casters, supporting lead plates, baffles, a radiation-proof transparent observation window, and a hand-operated hole. The door-frame structure ensures stability; the observation window allows direct observation of the operating area under shielding; the hand-operated hole facilitates precise operations; and the casters and mobile chassis ensure flexible deployment and relocation of the device. This design integrates shielding, observation, and operation, improving the safety and convenience of maintenance work.

[0042] V. Key Material Selection: The collimator and proton trap body are made of oxygen-free copper, which balances good thermal conductivity, mechanical properties, and machinability. Graphite is used as the protective material for key irradiated surfaces. High-density lead is used as the main shielding material to efficiently attenuate gamma radiation.

[0043] In summary, the design principles of this invention can be summarized as: "source suppression, rapid assembly and disassembly, partial shielding, and user-friendly operation." This integrated design ultimately achieves the comprehensive goals of significantly reducing operational and maintenance dosages, greatly improving maintenance efficiency, and comprehensively enhancing system safety.

[0044] Based on the above principles, this invention designs a device for reducing operational and maintenance doses at an isotope production target station, comprising a collimator and a proton trap. Its features include: graphite protective layers are provided on the end face of the collimator directly irradiated by the beam, and around the guide ramp through which the beam passes inside the proton trap, to absorb radiation and reduce equipment activation; quick-connect chuck structures are respectively configured on the exterior of the collimator and the proton trap for rapid installation and disassembly; a pair of movable lead shielding devices, A and B, are also provided on the exterior of the collimator and the proton trap, driven by a drive mechanism, capable of moving towards each other to both sides of the collimator and the proton trap during maintenance to provide localized radiation shielding; the collimator forms four end faces along the beam envelope for beam confinement.

[0045] Supplementary Note 1

[0046] The main body of the collimator and proton trap mentioned above is made of oxygen-free copper.

[0047] Furthermore, the provision of a graphite protective layer on the end face of the collimator that is directly irradiated by the beam means that a graphite protective layer is provided on the four end faces of the collimator that trap the beam.

[0048] Furthermore, the provision of a graphite protective layer around the guide ramp through which the proton trap beam passes specifically involves setting a graphite protective layer within a defined height and width range above the front baffle, the rear baffle, and the guide ramp between the front and rear baffles where the beam passes through the guide ramp.

[0049] Furthermore, the provision of a graphite protective layer within a specified height range above the guide ramp at the front baffle, rear baffle, and between the front and rear baffles of the beam means that: the height and width of the graphite protective layer at the front baffle match the coverage area of ​​the beam when it passes the front baffle; the height and width of the graphite protective layer at the rear baffle match the coverage area of ​​the beam when it passes the rear baffle; and the height and width of the graphite protective layer within a specified height and width range above the guide ramp match the coverage area of ​​the beam when it passes the guide ramp.

[0050] Supplementary Note 2

[0051] The effect of setting a graphite protective layer Figure 2 As shown, the first, Figure 2 and Figure 1 In comparison, the red area in the center of the target is significantly reduced; the red area represents the region with the highest dose. Secondly... Figure 2 compared to Figure 1 In the left graph, the outer curve changes color from red to blue; blue indicates the lowest radiation dose. Thirdly... Figure 2 Left image and Figure 1 In comparison, the overall radiation area has been significantly reduced, and these changes are all due to the application of a graphite protective layer.

[0052] Supplementary Note 3

[0053] The above-mentioned proton trap is equipped with a graphite protective layer, such as Figure 3 As shown, the beam enters the guide ramp from the right side. The beam first covers the front baffle area and then the rear baffle area. Therefore, the height of the graphite protective layer in the front baffle area is greater than that in the rear baffle area. Also, since the beam is biased upwards when passing through the guide ramp, the graphite protective layer between the front and rear baffles is also biased upwards towards the guide ramp.

[0054] Supplementary Note 4

[0055] The above quick-connect chuck structure is as follows: Figure 4a , Figure 4b As shown, quick-connect chuck-type structures are respectively installed on the proton trap and upper collimator on the upper surface of the vacuum chamber. The quick-connect chuck-type structure uses quick-release chain clamps for fixation, and a lifting structure for auxiliary disassembly and assembly is designed on its top. Special tooling is required to disassemble the quick-release chain clamps; rotating the tooling counterclockwise loosens the chain clamps, allowing the upper collimator and vacuum chamber to be separated.

[0056] Supplementary Note 5

[0057] The graphite protective layer is fixed to the substrate of the collimator or proton trap by welding, and the surface of the graphite protective layer welded to the substrate is metallized.

[0058] Supplementary Note 6

[0059] Figure 5 This is an AA cross-sectional view of the collimator and proton trap. The beam first passes through the proton collimator on the left and then through the proton trap on the right.

[0060] like Figure 4a , Figure 4b As shown, lead shielding device A and lead shielding device B are each equipped with their own support frame, casters, lead plates, and support baffles on the lead plates. The support frame is door frame shaped. The lead plates are embedded in the upper part of the support frame, and the height and width of the lead plates match the height and width of the radiation areas of the collimator and proton trap. Each lead plate is equipped with radiation-proof baffles to protect the human head and sides. Radiation-proof transparent observation windows and hand holes are also provided on the lead plates. The radiation-proof transparent observation windows are used for operator observation, and the hand holes are used for operation. Each drive mechanism is connected to lead shielding device A and lead shielding device B respectively, and is used to drive them to the working position or to withdraw. Each mobile chassis is set at the bottom of lead shielding device A and lead shielding device B respectively, and is used to support and move the devices.

[0061] Supplementary Note 7

[0062] Figure 4 , , The trajectory for target transport, from the proton trap. Removed and rotated into the pneumatic transmission pipeline in an atmospheric environment, the target inlet is then inserted. This process generates strong radiation. Therefore, Figure 6 The height and width of the supporting lead plate are also designed to block the radiation path of the target.

[0063] Furthermore, the drive mechanism includes a DC brake motor with a power-off self-locking function.

[0064] Supplementary Note 8

[0065] like Figure 5 As shown in the side sectional view, the upper and lower blocks on the left side of the side sectional view represent the end faces of the upper and lower collimator bundles respectively (the beam passes through the middle of the upper and lower end faces). The left side is the end face of the front and rear collimator bundles. Since the collimators are arranged front and rear, only one of the two bundle end faces can be seen in the sectional view.

[0066] Example 1:

[0067] The collimator and proton trap are made of oxygen-free copper. Without changing the channel dimensions formed by the collimators (upper, lower, left, and right), a graphite protective layer is added to the portion of the collimator directly irradiated by the beam. The graphite layer has a guide ramp, similar to the original collimator end. Graphite protective layers are also added to the lower end face of the proton trap, the red square area on the front baffle end face, the red square area on the lower end face of the rear baffle, and the red square area above the guide ramp (as shown in the attached diagram). Figure 3 (As shown in the red box in the middle), the added graphite protective layer is achieved through welding. Before welding, the graphite surface is metallized, and its coefficient of thermal expansion is close to that of oxygen-free copper, ensuring a strong weld. The dose distribution diagram after collimator activation following graphite welding is shown below (e.g., ...). Figure 2 As shown, after the collimator was activated by graphite, the surface dose of the solid target station decreased from 100 mSv / h to 26 mSv / h. The main nuclide produced after graphite activation was Be-7 (half-life 53.22 days), which has a shorter half-life than the radionuclides produced after copper activation, showing a clear advantage.

[0068] Example 2:

[0069] In high-energy isotope production target stations, the highly activated components are the proton trap, upper and lower collimators, and left and right collimators. To enable rapid disassembly of these components, they are designed with quick-connect chuck-type structures, secured using quick-release chain clamps, and equipped with lifting structures at the top for auxiliary assembly and disassembly (such as...). Figure 4b (As shown). Special tooling is required to disassemble the quick-release chain clamp. Rotate the tooling counterclockwise to loosen the chain clamp so that the upper collimator and vacuum chamber are separable.

[0070] Example 3:

[0071] During the maintenance of high-energy isotope production target stations, personnel must not directly operate the maintenance equipment; radiation protection devices such as lead shielding must be used to protect maintenance personnel from radiation (e.g., ...). Figure 6As shown, the DC brake motor is started and stopped by a control switch, which is equipped with an emergency stop button to deal with emergencies. In the event of a power outage or other sudden situation, the DC brake motor will lock immediately, preventing the lead plate from falling off.

[0072] Meanwhile, the lead plate and the support are connected by a guide rail groove to prevent the lead plate from tipping over. Limiting devices such as limiting blocks are also set in the vertical direction to prevent it from coming off in the vertical direction. The DC brake motor can drag the lead plate up and down to achieve flexible operation such as controlling the position of the lead plate. The lead glass can provide maintenance personnel with a field of vision for maintenance positions. The arm hole can be opened by pulling out the handle, and the arm can pass through to operate. The casters are AGV high load-bearing casters, which can realize the movement and steering of the electric control device. The counterweight is used to balance the DC brake motor and prevent uneven weight distribution at the bottom of the device.

[0073] It should be emphasized that the above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A device for reducing operational and maintenance doses at an isotope production target station, comprising a collimator and a proton trap, characterized in that: Graphite protective layers are provided on the end face of the collimator directly irradiated by the beam, and around the guide ramp of the beam inside the proton trap, to absorb radiation and reduce equipment activation. Quick-connect chuck structures are respectively configured on the outside of the collimator and the proton trap for rapid installation and removal of the equipment. The collimator and the proton trap are also equipped with a pair of movable lead shielding devices, namely lead shielding device A and lead shielding device B. The lead shielding devices are driven by a drive mechanism and can move towards each other to both sides of the collimator and the proton trap during maintenance to provide local radiation shielding. The collimator forms four end faces along the beam envelope to limit the beam.

2. The device for reducing operational and maintenance dosage at an isotope production target station according to claim 1, characterized in that, The provision of a graphite protective layer on the collimator end face directly irradiated by the beam means that a graphite protective layer is provided on the four end faces of the collimator that trap the beam.

3. The device for reducing operational and maintenance dosage at an isotope production target station according to claim 1, characterized in that, The provision of a graphite protective layer around the guide ramp through which the proton trap beam passes specifically involves setting a graphite protective layer within a defined height and width range above the front baffle, the rear baffle, and the guide ramp between the front and rear baffles where the beam passes through the guide ramp.

4. The device for reducing operational and maintenance dosage at an isotope production target station according to claim 3, characterized in that, The provision of graphite protective layers at the front baffle, rear baffle, and above the guide ramp between the front and rear baffles within a specified height range means that: the height and width of the graphite protective layer at the front baffle match the coverage area of ​​the beam passing through the front baffle; the height and width of the graphite protective layer at the rear baffle match the coverage area of ​​the beam passing through the rear baffle; and the height and width of the graphite protective layer within a specified height range above the guide ramp match the coverage area of ​​the beam passing through the guide ramp.

5. The device for reducing operational and maintenance dosage at an isotope production target station according to claim 1, characterized in that, The lead shielding device A and lead shielding device B are each equipped with their own support frame, casters, lead plates, and support baffles on the lead plates. The support frame is door frame shaped. The lead plates are embedded in the upper part of the support frame, and the height and width of the lead plates match the height and width of the radiation areas of the collimator and proton trap. Each lead plate is equipped with radiation-proof baffles to protect the top and sides of the human body. Radiation-proof lead glass observation windows and hand holes are also provided on the lead plates. The radiation-proof lead glass observation windows are used for operator observation, and the hand holes are used for operator insertion. Each drive mechanism is connected to lead shielding device A and lead shielding device B respectively, and is used to drive them to the working position or to withdraw. Each mobile chassis is set at the bottom of lead shielding device A and lead shielding device B respectively, and is used to support and move the devices.

6. The apparatus for reducing operational and maintenance dosage at an isotope production target station according to claim 5, characterized in that, The drive mechanism includes a DC brake motor with a power-off self-locking function.

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