The present teachings relate to systems and methods for the storage and processing of radioisotopes.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Large-scale production of radioisotopes is now possible, necessitating safe storage of large quantities of the irradiated materials. Generally, the radioisotopes comprise pellets, wires, disks, etc., of a desired isotopic material, e.g., cobalt, that has been irradiated to have a desired radioactivity. In many instances, these radioisotopes will be used to construct, or assemble, many different customer specified source capsules having many different desired activity profiles, i.e., many different containers having one or more radioisotopes sealed therein to provide various desired activity profiles. The operations required for such encapsulation must be done in a shielded facility and require large amounts of repetitive work to be performed.
Traditionally, an inventory of various isotopes is stored in a plurality of storage structures. Particularly, rods or tubes in which the radioisotopes are produced are stored in a plurality of radioactive shielded storage structures. To assemble, or construct, a source capsule having a particular customer requested activity profile, radioisotopes of various radioactivity, from various storage structures, are placed in radioactive shielded casks, removed from the respective storage structures. The casks are then transported to a separate assembly facility, commonly referred to as a ‘hot cell’. Once the various radioisotopes have been transported to the hot cell, the casks will be opened to access the respective radioisotopes. The desired amount of each respective radioisotope will be then removed and sealed in a capsule, e.g., a stainless steel container, to provide a source capsule having the desired activity profile. The unused radioisotopes will then be returned to the casks. The casks will then be removed from the hot cell and transported back to the respective storage structures.
Thus, the process of loading the various radioisotopes stored in the various storage structures in casks, transporting the casks to the hot cell, opening the casks to access the radioisotopes, assembling the source capsules, repacking the casks and returning the casks to the storage structures is a cumbersome and time consuming task.
In various embodiments, a system for storing radioactive material is provided, wherein the system includes a storage pool for storing a plurality of radioactive objects submersed in a radiation shielding and cooling liquid. The system additionally includes an assembly building located above the storage pool for constructing one or more radioactive article using the radioactive objects transferred from the storage pool. Furthermore, the system includes at least one transfer shaft connecting the storage pool and the assembly building. The transfer shaft(s) is/are used for transferring the radioactive objects directly from within the storage pool to an interior of the assembly building and directly from the interior of the assembly building into the storage pool.
In various other embodiments, a system for storing radioactive material is provided, wherein the system includes a storage pool disposed within and beneath a floor of the system. The storage pool is structured for storing a plurality of radioisotopes submersed in a radiation shielding and cooling liquid. The system additionally includes a capsule assembly building disposed on the system floor above the storage pool. The capsule assembly building can include an assembly chamber comprising a plurality of interior cells for constructing one or more radioactive capsules using radioisotopes transferred from the storage pool to the capsule assembly building. The system further includes at least one transfer shaft connecting the storage pool and the capsule assembly building to provide direct access to the storage pool from an interior of the capsule assembly building. Therefore, the transfer shaft(s) provide for transferring the radioisotopes from within the storage pool directly to the interior of the capsule assembly building and from the interior of the capsule assembly building directly into the storage pool.
In still other embodiments, a method for storing radioactive material is provided, wherein the method includes storing a plurality of radioisotopes submersed in a radiation shielding and cooling liquid within a storage pool, and transferring selected radioisotopes directly from within the storage pool to an interior of an assembly chamber of an assembly building. The assembly building can be located above the storage pool. The selected radioisotopes are transferred from within the storage pool directly to the interior of an assembly chamber via at least one transfer shaft connecting the storage pool and the assembly building. The method additionally includes constructing one or more radioactive capsules within the assembly chamber using the radioisotopes transferred from the storage pool. The method further includes transferring the selected radioisotopes not used to construct the one or more radioactive capsules directly from the interior of the assembly chamber into the storage pool using the at least one transfer shaft.
Further areas of applicability of the present teachings will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present teachings in any way.
The following description is merely exemplary in nature and is in no way intended to limit the present teachings, application, or uses. Throughout this specification, like reference numerals will be used to refer to like elements.
The storage pool 14 is structured to be filled with a radiation shielding and cooling liquid, e.g., water, such that a plurality of radioactive objects 26 and/or a plurality of radioactive articles 28 constructed from the radioactive objects 26 can be submerged and stored therein. The radioactive articles 28 and/or radioactive objects 26 can comprise any radioactive material such as Cobalt 60 (Co-60), iridium, nickel, etc. In various embodiments, the radiation shielding and cooling liquid can be circulated through a chiller (not shown) to cool the liquid in order to provide a desired cooling for the stored radioactive objects 26 and/or articles 28.
The cooling liquid captures decay heat emanated from the radioactive objects 26 and/or radioactive articles 28 submerged within the storage pool 14. The amount of heat needing to be dissipated is dependent on the curie content of the storage pool 14 and the specific radioactive objects 26 and/or radioactive articles 28 being stored. As an example, if the storage pool 14 were near its capacity for storage of Cobalt 60 (Co-60) radioactive objects 26 and/or radioactive articles 28, generating 0.015 Wafts/Ci, then the cooling liquid (optionally circulated through a chiller) can be utilized to maintain radioactive objects 26 and/or radioactive articles 28 at approximately 100° F. In alternative implementations the cooling liquid (optionally circulated through a chiller) can be utilized to maintain radioactive objects 26 and/or radioactive articles 28 at approximately 100° F. to 200° F.
Additionally, it is envisioned that the storage pool 14 can be sized to hold a very large quantity, e.g., thousands, of the radioactive objects 26 and/or articles 28. The assembly building 18 is constructed to be a radiation shielding and containment structure suitable for safely housing radioactive objects 26 and/or articles 28 transferred directly from the storage pool 14 to an interior of the assembly building 18, via the transfer shafts 22. As described further below, in operation, to construct the radioactive article(s) 28, radioactive objects 26 are selected from within the storage pool 14 and transferred directly to an interior of the assembly building 18 where the radioactive objects 26 are used to construct one or more radioactive articles 28 for a particular use.
For example, in various embodiments, the radioactive objects 26 can comprise radioactive rods 32 containing various radioisotopes having various radioactive intensities and the radioactive articles 28 can comprise source capsules 34 that have been constructed within the assembly building 18 to have desired activity profiles and returned to the storage pools 14 for safe storage. Particularly, a large number of radioactive rods 32 and/or source capsules 34 can be stored in a plurality of racks 40 within the storage pool 14. To assemble, or construct, the source capsules 34, one or more rods 32 containing particular radioisotopes can be transferred directly from the storage pool 14 to the interior of a radioactive containing assembly chamber 42 of the assembly building 18, via the transfer shafts 22. Once the rods 32 have been transferred into the assembly chamber 42, the rods 32 can be opened to access the respective radioisotopes. The radioisotopes can then be used to construct one or more radioactive source capsules 34 having desired activity profiles. The source capsules 34 can then either be returned to the storage pool 14 for storage or transported to a desired location, e.g., a medical facility for use in medical imaging and/or treatment. In such embodiments, the assembly can also be referred to as the capsule assembly chamber 42.
In various embodiments, the assembly building 18 is located above, or higher, and in close proximity to, the storage pool 14 such that the radioactive objects 26 and/or articles have a relatively short distance to travel through the transfer shafts 22 when being transferred between storage pool 14 and the assembly building 18. For example, in various embodiments, as illustrated in
Additionally, in various embodiments, as illustrated in
Referring to
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In various implementations, the assembly cells 74 include at least one docking cell 74A, e.g., the centermost assembly cell 74, and at least one other assembly cell 74 for constructing the one or more radioactive articles therein. A disposition end 92 of each transfer shaft 22 (shown in
Referring now to
The conveyor 114 can be any system, device or mechanism suitable for conveying, i.e., transferring, moving or translating, the elevator system tray(s) 110, and any radioactive object 26 and/or article 28 placed thereon, along the interior length of the respective transfer shaft 22. For example, the conveyor 114 can be a conveyor-belt type system, a chain-and-sprocket type system, a cable-and-pulley type system, a threaded shaft type system, any combination thereof, or any other suitable conveying system.
Referring now to
As will be appreciated, the object manipulators 122 are controllable by facility personnel, e.g., operators 126 (
In operation, to assemble, or construct, one or more radioactive articles 28, one or more of the plurality of radioactive objects 26, e.g., radioisotope rods 32, stored in the storage pool 14 is/are selected, removed from the respective one of the plurality of racks 40, and moved to one of the storage pool side wall apertures 102. The radioactive object(s) 26 is/are selected based on particular desired characteristics of the particular object(s) 26, i.e., size, material, isotope, radioactivity, etc. Once the selected radioactive object(s) 26 have been moved to the storage pool side wall apertures 102, the radioactive object(s) 26 is/are placed on the elevator system tray 110 for transfer directly to the assembly chamber interior docking cell 74A.
Any suitable means can be employed to remove the selected radioactive object(s) 26 from the respective rack(s) 40, move the selected radioactive object(s) 26 to one of the storage pool side wall apertures 102 and place the selected radioactive object(s) 26 on the elevator system tray 110. For example, robotic devices, mechanisms, assemblies or systems (not shown) can be utilized to select the radioactive object(s) 26, move them to one of the storage pool side wall apertures 102 and place them on the elevator system tray 110. Or, alternatively, long mechanical grasping poles can be disposed into the storage pool and hand manipulated by facility personnel from the facility floor 30 to select the radioactive object(s) 26, move them to one of the storage pool side wall apertures 102 and place them on the elevator system tray 110.
After the selected radioactive object(s) 26 have been placed on the elevator system tray 110, the elevator system conveyor 114 is operated to transfer the selected radioactive object(s) 26 directly from the storage pool 14, through the respective transfer shaft 22 directly into the interior of the assembly chamber 42, i.e., directly into the docking cell 74A. The object manipulators 122 and/or the overhead crane device 78 and/or the under-floor conveyor system 84 can then be operated to manipulate the transferred radioactive object(s) 26 and move them from the docking cell 74A to one or more of the various other assembly cells 74. Once the radioactive object(s) 26 have been delivered to the one or more assembly cells 74, the facility personnel can operate the object manipulators 122 to assemble/construct, the radioactive articles, e.g., radioactive source capsules 34. The object manipulators 122 can also be utilized to place or package the assembled/constructed radioactive articles in shielded containers or casks. The overhead crane device 78 can then be operated to move the packaged radioactive articles into one of the interlocks 46 from which the packaged radioactive articles can be safely removed for delivery to a selected location.
Subsequently, the object manipulators 122 and/or the overhead crane device 78 and/or the under-floor conveyor system 84 can then be operated to manipulate the unused radioactive object(s) 26 and move them from the one or more assembly cells 74 to the docking cell 74A for return to the storage pool 14. The unused radioactive object(s) 26 can then be placed into one of the docking cell floor apertures 94 and onto a respective elevator system tray 110. The elevator system conveyor 114 is then operated to transfer the unused radioactive object(s) 26 directly from the interior of the assembly chamber 42, i.e., directly from the docking cell 74A, through the respective transfer shaft 22 and directly to the respective storage pool side wall aperture 102. The returned unused radioactive object(s) 26 can then be returned to the proper rack 40 submersed within the shielding and cooling liquid of the storage pool 14.
Referring now to
It should be understood that spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The description herein is merely exemplary in nature and, thus, variations that do not depart from the gist of that which is described are intended to be within the scope of the teachings. Such variations are not to be regarded as a departure from the spirit and scope of the teachings.