Patent Publication Number: US-2023136825-A1

Title: Cooling enhancements for dry fuel storage

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/976,021 filed Feb. 13, 2030, the contents of which is hereby incorporated by reference in its entirety herein. 
    
    
     BACKGROUND 
     The present invention relates to spent nuclear fuel storage systems. 
       FIG.  1    illustrates a typical pressurized water nuclear reactor fuel assembly  20  for supplying nuclear fuel to a reactor. Fuel assembly  20  includes a bottom nozzle  22  and a top nozzle  24 . Elongated fuel rods  26  are disposed between the bottom nozzle  22  and the top nozzle  24 . Each fuel rod  26  includes a cylindrical housing made of zirconium alloy such as commercially available “zircaloy-4”, and is filled with pellets of fissionable fuel enriched with U-235, Within the assembly of fuel rods  26 , tubular guides (not shown) are disposed between nozzles  22  and  24  to accommodate movably mounted control rods (not illustrated) and measuring instruments (not illustrated), The ends of these tubular guides are attached to nozzles  22  and  24  to form a skeletal support for fuel rods  26 , which are not permanently attached to nozzles  22  and  24 . Grid members  28  have apertures through which fuel rods  26  and the tubular guides extend to bundle these elements together. Commercially available fuel assemblies include between 179 and 264 fuel rods, depending upon the particular design. A typical PWR fuel assembly, for example, is about 4.1 meters long, about 19.7 cm wide, and has a mass of about 585 kg. 
     After a typical service life of 4-5 years in a pressurized water reactor (PWR), the U-235 enrichment of a fuel assembly  20  is depleted. Furthermore, a variety of fission products, having various half-lives, are present in rods  26 , These fission products generate intense radioactivity and heat when assemblies  20  are removed from the reactor, and accordingly the assemblies  20  are moved to a pool containing boron salts dissolved in water for short-term storage. Such a pool is designated by reference number  30  in  FIG.  2   . 
     Pool  30  is typically 12.2 meters deep. A number of spent fuel racks  32  positioned at the bottom of pool  30  are provided with storage slots  34  that vertically accommodate fuel assemblies  20 . A cask pad  36  is located at the bottom of pool  30 . 
     During the period when fuel assemblies  20  are stored in pool  30 , the composition of the spent fuel in rods  26  changes. Isotopes with short half-lives decay, and consequently the proportion of fission products having relatively long half-lives increases. Accordingly, the level of radioactivity and heat generated by a fuel assembly  20  decreases relatively rapidly for a period and eventually reaches a state wherein the heat and radioactivity decrease very slowly. Even at this reduced level, however, rods  26  must be reliably isolated from the environment for the indefinite future. 
     Dry storage casks provide one form of long-term storage for the spent fuel. After the heat generated by each fuel assembly  20  falls to a predetermined amount—such as 0.5 to 1.0 kilowatt per assembly, after perhaps 10 years of storage in pool  30 —an opened cask is lowered into a spent fuel pool. By remote control the spent fuel is transferred to the cask, which is then removed from pool  30 , sealed, and drained of spent fuel pool water. The cask can then be suitably processed and transported to an above-ground storage area for long-term storage. 
     The requirements which must be imposed on such a cask are rather severe. The cask must be immune from chemical attack during long-term storage. Furthermore, it must be sufficiently rugged mechanically to avoid even tiny ruptures or fractures during long-term storage and during transportation, when the cask might be subjected to rough treatment or accidents such as drops. Moreover, the cask must be able to transmit heat generated by the spent fuel to the environment while nevertheless shielding the environment from radiation generated by the spent fuel. The temperature of the rods  26  must be kept below a maximum temperature, such as 400° C., to prevent deterioration of the zirconium alloy housing. Provisions must also be made to ensure that a chain reaction cannot be sustained within the cask; that is, that the effective criticality factor K eff  remains less than one so that a self-sustaining reaction does not occur. These requirements impose stringent demands upon the cask, which must fulfill its storage function in an utterly reliable manner. 
     A modular dry spent fuel canister system is a system in which one of several different types of inner spent nuclear fuel canisters (typically welded stainless or carbon steel right circular cylinders) can be loaded into one of an outer cask family, depending on the stage of storage the inner canister is undergoing. This family of outer casks would typically include a storage overpack for long term dry storage, a transfer cask for transferring the fuel assemblies out of the spent fuel pool, and a transportation cask for shipping the fuel assemblies to a different storage location. For a modular system, the various canisters can be loaded interchangeably into the different types of outer casks. 
     As presently supplied modular spent fuel canister systems offer an inner canister designed for one type of spent fuel or another (e.g., BWR, PWR, PWR XL, or VVER fuel), or Greater than Class C Waste (GTCC). However, the industry would be better served if various canisters were designed for a focused engineering objective or criterion that would apply to the high level waste being stored rather than simply to the type of spent radioactive waste being stored. 
     Commonly owned U.S. patent application Ser. No. 16/257,776, titled “DUEL-CRITERION FUEL CANISTER SYSTEM”, which published as U.S. Patent Application Publication No. 2019/0237210 on Aug. 1, 2019, which is incorporated by reference in its entirety herein, discloses a minimum cooling time canister (MCTC) that provides various enhancements to reduce the cooling time or radioactive decay time that must pass before the MCTC can be moved to a new location so as to meet the decay heat requirements and capabilities of the new location. 
     One such enhancement is a vent and duct system  110 , illustrated in  FIG.  3   , between an inner canister  142  and a storage overpack  112  that configured to remove heat from the inner canister  142 . The vent and duct system  130  includes an intake  132  defined in a lower portion of a storage overpack  112 , an outlet  134  defined in an upper portion of the storage overpack  112 , and a duct  136  extending between the intake  132  and the outlet  134  between an inner side (not numbered) of the storage overpack  112  an outer side (not numbered) of the inner canister  142 . In one embodiment, the duct  136  is an annular passage between the storage overpack  112  and the inner canister  142 . This technology represents the ability of the system to use natural convection to remove heat from the surface of the inner canister  142 . In one embodiment, an annular gap is provided between the inside wall of the storage overpack  112  and the outside wall of the MCTC  142  with the duct and vent system  130  that removes heat from the inner canister surface as well as the storage overpack  112 . 
     It is desirable to improve upon the vent and duct system by providing a storage overpack that increases airflow through the annular passageway to further reduce cooling times, as well as improves radiation shielding to reduce radiation exposure generated by the spent fuel. 
     SUMMARY 
     The present invention achieves the foregoing objectives by providing a storage overpack with inlet vents and outlet vents with curved transitions, which result in an improved airflow compared to vents with straight edges and elbows. The present invention also provides horns that can mount to the inlet vents and outlet vents to improve airflow through an annular passage of a storage overpack. 
     In various embodiments, a nuclear component handling arrangement is disclosed including a storage overpack including an inner envelope, an inner canister including an outer envelope, wherein the inner canister is positionable within the storage overpack, and a vent and duct system including an inlet vent, an outlet vent, and a passageway defined between the inner envelope of the storage overpack and the outer envelope of the inner canister. The inlet vent includes an inlet entrance, an inlet exit, and a curved transition surface extending between the inlet entrance and the inlet exit. The passageway extends between the inlet vent and the outlet vent. 
     In various embodiments, a nuclear component handling arrangement is disclosed including a storage overpack including an inner envelope, an inner canister including an outer envelope, wherein the inner canister is positionable within the storage overpack, and a passive cooling system including an inlet vent, an outlet vent, and a duct defined between the inner envelope of the storage overpack and the outer envelope of the inner canister. The inlet vent includes an inlet entrance portion, an inlet exit portion, and a curved portion connecting the inlet entrance portion and the inlet exit portion. The duct extends between the inlet vent and the outlet vent. 
     In various embodiments, a nuclear component handling arrangement for housing a canister containing nuclear waste is disclosed. The nuclear component handling arrangement includes a storage overpack including an inner envelope, wherein the canister is positionable within the storage overpack, and a passive cooling system comprising an inlet vent, an outlet vent, and a duct extending between the inlet vent and the outlet vent. The inlet vent includes an inlet horn, an inlet exit portion, and a curved portion connecting the inlet horn and the inlet exit portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features of the embodiments described herein, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings as follows: 
         FIG.  1    is an elevation view of a typical pressurized water reactor fuel assembly. 
         FIG.  2    is a top plan view of a pool for short-term storage of spent fuel assemblies. 
         FIG.  3    is an isometric view of a dry nuclear component handling arrangement shown with a portion of an outer cask thereof sectionally removed in order to show details of the outer cask as well as an inner canister of the arrangement. 
         FIG.  4 A  is one embodiment of a nuclear component handling arrangement with a portion of the cask housing removed, according to one aspect of the present disclose. 
         FIG.  4 B  is an isometric view of the nuclear component handling arrangement of  FIG.  4 A , according to one aspect of the present disclose. 
         FIG.  4 C  is another embodiment of the nuclear component handling arrangement with a portion of the cask housing removed, according to one aspect of the present disclose. 
         FIG.  4 D  is an isometric view of the nuclear component handling arrangement of  FIG.  4 C , according to one aspect of the present disclose. 
         FIG.  4 E  is another embodiment of the nuclear component handling arrangement with a portion of the cask housing removed, according to one aspect of the present disclose. 
         FIG.  4 F  is an isometric view of the nuclear component handling arrangement of  FIG.  4 E , according to one aspect of the present disclose. 
         FIG.  4 G  is an embodiment of the nuclear component handling arrangement, according to one aspect of the present disclose. 
         FIG.  4 H  is an isometric view of the nuclear component handling arrangement of  FIG.  4 G , according to one aspect of the present disclose. 
         FIG.  4 I  is an embodiment of the nuclear component handling arrangement with vertically aligned inlet and outlet vents, according to one aspect of the present disclose. 
         FIG.  4 J  is an embodiment of the nuclear component handling arrangement with angularly offset inlet and outlet vents, according to one aspect of the present disclose. 
         FIG.  5 A  is one embodiment of a horn configured for use with a nuclear component handling arrangement, according to one aspect of the present disclose. 
         FIG.  5 B  is one embodiment of a horn coupled with an inlet vent of a nuclear component handling arrangement, according to one aspect of the present disclose. 
         FIG.  5 C  is a back view of a horn, according to one aspect of the present disclose. 
         FIG.  5 D  is a top cross-sectional view of the horn of  FIG.  5 C , according to one aspect of the present disclose. 
         FIG.  5 E  is a side cross-sectional view of the horn of  FIG.  5 C , according to one aspect of the present disclose. 
         FIG.  5 F  is an enlarged portion of the horn of  FIG.  5 E , according to one aspect of the present disclose. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various embodiments of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     Before explaining various aspects of a nuclear component handling arrangement in detail, it should be noted that the illustrative examples are not limited in application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The illustrative examples may be implemented or incorporated in other aspects, variations, and modifications, and may be practiced or carried out in various ways. Further, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative examples for the convenience of the reader and are not for the purpose of limitation thereof. Also, it will be appreciated that one or more of the following-described aspects, expressions of aspects, and/or examples, can be combined with any one or more of the other following-described aspects, expressions of aspects, and/or examples. 
       FIGS.  4 A and  4 B  illustrate a nuclear component handling arrangement  200  in accordance with one non-limiting embodiment of the present disclosure. While the following discussion is made in reference to  FIGS.  4 A and  4 B , several other nuclear component handling arrangements  300 ,  400 ,  500 ,  600 ,  700  in accordance with other non-limiting embodiments of the present disclosure, illustrated in  FIGS.  4 C- 4 J , are provided. Similar components described hereinbelow are similarly labeled in  FIGS.  4 C- 4 J . Referring to  FIGS.  4 A and  4 B , the arrangement  200  includes an outer cask  202  (referred to herein as a “storage overpack”) and an inner canister  204  selectively disposed within the storage overpack  202 . The storage overpack  202  includes a cask housing  203  defining an interior envelope  206  that is generally cylindrical in shape. The cask housing  204  can generally include a cylindrical-shaped concrete body, a tubular-shaped auxiliary shielding shell  208  disposed internally and being generally concentric with the housing  203 , and a storage lid  210  which is selectively coupled to cask housing  203  via bolts  212  or other suitable coupling mechanisms. The shielding shell  208  assists with performing shielding functions. 
     The inner canister  204  has a canister housing  214  which is configured to store a quantity of irradiated nuclear plant components or high level waste, such as a plurality of PWR fuel assemblies and/or a plurality of Boiling Water Reactor (BWR) fuel assemblies therein. Furthermore, the canister housing  214  has an outer envelope  215 , generally cylindrical in shape, which is configured to fit within the interior envelope  206  of the storage overpack  202 . An annular duct, gap or passage  216  is defined between the interior envelope  206  of the storage overpack  202  and the outer envelope  215  of the canister housing  204 . In addition, pipes  218  can be disposed between a base of the inner canister  204  and the floor of the storage overpack  202  to provide additional structural support to the nuclear component handling arrangement  200  and to provide support to the inner canister  204  within the storage overpack  202 . 
     The nuclear component handling arrangement  200  can further include a vent and duct system  300  that is configured to remove heat from the inner canister  204 . The vent and duct system  300  includes at least one inlet vent  302  defined in a bottom portion of the storage overpack  202  and at least one outlet vent  304  defined in an upper portion of the storage overpack  202 . In one embodiment, the inlet vents  304  and outlet vents  304  can be defined along the bottom portion of the storage overpack  202  and top portion of the storage overpack  202 , respectively. In other embodiments, the inlet vents  302  and outlet vents  304  can be defined at other locations other than the bottom portion and top portion of the storage overpack  202 , respectively, such as at various locations along the height of the cask housing  203 . The vent and duct system  300  can include any number of inlet vents  302  and outlet vents  304  disposed about the storage overpack  202  to facilitate adequate airflow therethrough and over the inner canister  204 . In one embodiment, the vent and duct system  300  can have an identical number of inlet vents  302  and outlet vents  304 . In another embodiment, the vent and duct system  300  can have more inlet vents  302  than outlet vents  304 , In another embodiment, the vent and duct system  300  can have more outlet vents  304  than inlet vents  302 . In one embodiment, referring to  FIG.  4 I , a nuclear component handling arrangement  600  can include inlet vents  302  and outlet vents  304  that can be substantially vertically aligned. In another embodiment, referring to  FIGS.  4 J , a nuclear component handling arrangement  700  can include inlet vents  302  and outlet vents  304  that can be angularly offset about the circumference of the storage overpack  202  with respect to one another such that the inlet vents  302  and outlet vents  304  are not vertically aligned. In one example embodiment, a storage overpack  202  can include inlet vents  302  and outlet vents  304  that are 30° offset about the circumference of the storage overpack  202 . In another example embodiment, a storage overpack  202  can include inlet vents  302  and outlet vents  304  that are 45° offset about the circumference of the storage overpack  202 . In another example embodiment, a storage overpack  202  can include inlet vents  302  and outlet vents  304  that are 15° offset about the circumference of the storage overpack  202 . 
     In use, the vent and duct system  300  makes use of natural convection to remove the heat from the inner canister  204  through the “smokestack” effect of heating air expanding, and thus producing a pressure gradient capable of driving an upward-rising airflow. The gradient causes air to enter through the inlet vents  302 , travel through the annular passage  216  between the interior envelope  206  of the storage overpack  202  and the outer envelope  215  of the inner canister  204 , and exit through the outlet vents  304 . In one embodiment, the air is to enter the inlet vent  302  substantially horizontally and exit substantially vertically into the annular passageway  216  (conversely for the outlet vents). In other embodiments, the air is to enter and exit the vents  302 ,  304  at angles relative to the base of the storage overpack  202 . 
     Unlike other systems, referring to  FIG.  4 D , as an example, the present disclosure provides inlet vents  302  and outlet vents  304  with curved transitions  320 . Other existing systems make use of sharp turns and directional changes, which results in higher frictional resistance on air traveling through the storage overpack  202 . The use of curved transitions makes use of air circulation pathways more conducive to optimal airflow and substantially lowers friction losses, resulting in an improved airflow, higher velocities, and commensurately enhanced heat removable compared to vents with straight vents and sharp turns. Such a configuration allows for the establishment of substantially greater heat losses through the nuclear component handling arrangement  200 , which aids in accommodating significantly higher heat loads for the spent fuel contents of the inner canister  204 . 
     In addition, the use of curved transitions can result in improved radiation shielding when compared to vents with straight vents and sharp turns. In order to facilitate improved radiation shielding, it is important that the entrances to the inlet vents  302   a  and the exits of the outlet vents  304   b  be small such that radiation is prevented from leaking out of the nuclear component handling arrangement  200 . In one aspect, the entrance to the vents  302   a ,  304   a  can have a first cross-sectional area and the exit of the vents  302   b ,  304   b  can have a second cross-sectional area. In one embodiment, the first cross-sectional area and the second cross-sectional area can be substantially the same. In another embodiment, the first cross-sectional area and the second cross-sectional area can be different. In one embodiment, the cross-sectional areas of the entrances of the inlet vents  302   a  and the outlet vents  304   a  can be different. In another embodiment, the cross-sectional areas of the exits of the inlet vents  302   b  and the outlet vents  304   b  can be different. 
     In one aspect, the vents  302 ,  304  can have a rectangular cross sectional shape. In another aspect, the vents  302 ,  304  can have a square cross-sectional shape. In another aspect, the vents  302 ,  304  can have a circular cross sectional shape. In one embodiment, the inlet vent  302  can maintain a uniform cross sectional shape and the outlet vent  304  can maintain the same, or a different, cross sectional shape. In one embodiment, the entrance to the vents  302   a ,  304   a  can have one cross sectional shape and the exit to the vents  302   b ,  304   b  can have a different cross sectional shape. 
     In another aspect, the inlet vents  302  and outlet vents  304  can have curved transition surfaces, such as first transition surface  310   a  and second transition surface  310   b  that each transition from the entrance of vent  302   a  to the exit of vent  302   b . In one embodiment, the radius of curvature of the first transition surface  310   a  and the radius of curvature of the second transition surface  310   b  can be identical. In another embodiment, the radius of curvature of the first transition surface  310   a  and the radius of curvature of the second transition surface  310   b  can be different. The vents  302 ,  304  can have any number of transition surfaces between the entrance of the vents  302   a ,  304   a  and the exit of the vents  302   b ,  304   b  to facilitate an increase in airflow through the nuclear component handling arrangement  200 . In addition, the transition surfaces  310   a ,  310   b  can include both straight portions and curved portions, such that the air transitions from the substantially horizontal direction to the substantially vertical direction over only a portion of the distance between the entrance and the exit of the vents. In other embodiments, the transition surfaces  310   a ,  310   b  only include curved portions. 
     In another aspect of the present disclosure, referring now to  FIGS.  5 A- 5 F , a horn  800  is provided that can be configured for use with the vent and duct system  300  described hereinabove. The horn  800  is configured to further facilitate an increase in airflow through the nuclear component handling arrangement  200 . Similar to the vent and duct system  300 , the horn comprises inlets  802  and outlets  804  with curved transitions  806  to facilitate a reduction in friction experienced by the air. 
     The horn  800  is configured to be coupled with the entrance of the inlet vents  302   a  and exits of the outlet vents  304   b  at an interface  808 , The interface  808  is configured to couple to the vents  302 ,  306  by press-fit, friction-fit, a latch mechanism, a fastening mechanism, an adhesive, or any other suitable coupling mechanism to couple the horns  800  to the vents  302   a ,  304   b . In one aspect, horns  800  can be coupled to each of the inlet vents  302  and outlet vents  304 . In another aspect, horns  800  can be coupled to only the inlet vents  302 . In another aspect, horns can be coupled to only the outlet vents  304 . In another aspect, horns  800  can be selectively coupled to some inlet vents  302  and some outlet vents  304 . 
     In various embodiments, the horn  800  includes a first cross-sectional area at the inlet  802  of the horn  800  and a second cross-sectional area at the outlet  804  of the horn  800 . The second-cross sectional area at the interface  808  can be the same, or at least substantially the same, to the cross-sectional area of the entrance of the inlet vent  302   a  (or exits of the outlet vent  304   b ) to prevent air from leaking at the interface  808 , In one embodiment, the first cross-sectional area and the second cross-sectional area can be the same, or at least substantially the same. In another embodiment, the first cross-sectional area and the second cross-sectional area can be different. In another embodiment, the first cross-sectional area can be greater than and the second cross-sectional area. 
     In one aspect, the horns  800  can have a rectangular cross sectional shape. In another aspect, the horns  800  can have a square cross-sectional shape. In another aspect, the horns  800  can have a circular cross sectional shape. In one embodiment, the inlet to the horn  802  can have one cross sectional shape and the outlet to the horn  804  can have a different cross sectional shape. 
     In one aspect, the horns can have a transition surface, such as transition surface  806 , and a substantially flat surface, such as substantially flat surface  810 . In another aspect, the horn  800  can have a plurality of transition surfaces  806  that each transition from the entrance of the horn  802  to the exit of the horn  804 , In another aspect, the horns  800  can have a substantially flat surface  810  and transition surfaces  806 , In another one, the horn can comprise entirely of transition surfaces  806 . In another embodiment, the horns  800  can comprise entirely of substantially flat surfaces  810 , In one aspect, referring to  FIGS.  5 E and  5 F , the substantially flat surfaces  810  can comprise a transition surface  820  on the substantially flat surface  810  at the interface  808  to provide a better fit with the vents  302 ,  304 , along with provide additional air leakage resistance. 
     While a vent and duct system  300  and horn  800  are described hereinabove to improve airflow and reduce cooling time to the inner canister  204 , other systems and methods can be used in in tandem to further reduce the cooling time, such as outwardly extending fins on the inner canister, reduced capacity of spent fuel in the inner canister, or an active cooling system described in U.S. patent application Ser. No. 16/257,776, which has been incorporated by reference herein. Moreover, the inner canister can be structured to function as a minimum cooling time canister (MCTC) or a high capacity canister (HPC), also described in U.S. patent application Ser. No. 16/257,776. 
     Various aspects of the subject matter described herein are set out in the following examples. 
     Example 1—A nuclear component handling arrangement comprising a storage overpack comprising an inner envelope, an inner canister comprising an outer envelope, wherein the inner canister is positionable within the storage overpack, and a vent and duct system comprising an inlet vent, an outlet vent, and a passageway defined between the inner envelope of the storage overpack and the outer envelope of the inner canister. The inlet vent comprises an inlet entrance, an inlet exit, and a curved transition surface extending between the inlet entrance and the inlet exit. The passageway extends between the inlet vent and the outlet vent. 
     Example 2—The nuclear component handling arrangement of Example 1, wherein the outlet vent comprises an outlet entrance, an outlet exit, and a curved transition surface extending between the outlet entrance and the outlet exit. 
     Example 3—The nuclear component handling arrangement of Examples 1 or 2, wherein said inlet vent comprises a horn. 
     Example 4—The nuclear component handling arrangement of any of one Examples 1-3, wherein said outlet vent comprises a horn. 
     Example 5—The nuclear component handling arrangement of any of one Examples 1-4, wherein the inlet entrance comprises a first cross-sectional area, wherein the inlet exit comprises a second cross-section area, and wherein the first cross-sectional area and the second cross-sectional area are different. 
     Example 6—The nuclear component handling arrangement of Example 5, wherein the first cross-sectional area is less than the second cross-sectional area. 
     Example 7—The nuclear component handling arrangement of any of one Examples 1-6, wherein the curved transition surface is a first curved transition surface, wherein the vent and duct system comprises a second curved transition surface. 
     Example 8—The nuclear component handling arrangement of Example 7, wherein the first curved transition surface comprises a first radius of curvature, wherein the second curved transition surface comprises a second radius of curvature, and wherein the first radius of curvature and the second radius of curvature are different. 
     Example 9—A nuclear component handling arrangement comprising a storage overpack comprising an inner envelope, an inner canister comprising an outer envelope, wherein the inner canister is positionable within the storage overpack, and a passive cooling system comprising an inlet vent, an outlet vent, and a duct defined between the inner envelope of the storage overpack and the outer envelope of the inner canister. The inlet vent comprises an inlet entrance portion, an inlet exit portion, and a curved portion connecting the inlet entrance portion and the inlet exit portion. The duct extends between the inlet vent and the outlet vent. 
     Example 10—The nuclear component handling arrangement of Example 9, wherein the inlet entrance portion defines a horizontal passage leading to the curved portion. 
     Example 11—The nuclear component handling arrangement of Examples 9 or 10, wherein the inlet exit portion defines a vertical passage leading to the duct. 
     Example 12—The nuclear component handling arrangement of any of one Examples 9-11, wherein the duct is an annular duct. 
     Example 13—The nuclear component handling arrangement of any of one Examples 9-12, wherein the curved portion extends along a curved central axis, and wherein the curved portion maintains a uniform cross-sectional shape along the curved central axis. 
     Example 14—The nuclear component handling arrangement of any of one Examples 9-13, wherein the curved portion extends along a curved central axis, and wherein the curved portion comprises a plurality of different cross-sectional shapes along the curved central axis. 
     Example 15—The nuclear component handling arrangement of any of one Examples 9-14, wherein the curved portion comprises a first section and a second section narrower than the first section. 
     Example 16—The nuclear component handling arrangement of any of one Examples 9-15, wherein the curved portion extends along a curved central axis. 
     Example 17—The nuclear component handling arrangement of any of one Examples 9-16, wherein the outlet vent comprises an outlet entrance portion, an outlet exit portion, and a curved portion extending between the outlet entrance portion and the outlet exit portion. 
     Example 18—The nuclear component handling arrangement of any of one Examples 9-17, wherein said inlet vent comprises a horn. 
     Example 19—The nuclear component handling arrangement of any of one Examples 9-18, wherein said outlet vent comprises a horn. 
     Example 20—The nuclear component handling arrangement of any of one Examples 9-19, wherein the inlet entrance portion comprises a first cross-sectional area, wherein the inlet exit portion comprises a second cross-section area, and wherein the first cross-sectional area and the second cross-sectional area are different. 
     Example 21—The nuclear component handling arrangement of Example 20, wherein the first cross-sectional area is less than the second cross-sectional area. 
     Example 22—The nuclear component handling arrangement of any of one Examples 9-21, wherein the curved portion is a first curved portion, and wherein the passive cooling system comprises a second curved portion. 
     Example 23—The nuclear component handling arrangement of Example 22, wherein the first curved portion comprises a first radius of curvature, wherein the second curved portion comprises a second radius of curvature, and wherein the first radius of curvature and the second radius of curvature are different. 
     Example 24—A nuclear component handling arrangement for housing a canister containing nuclear waste, the nuclear component handling arrangement comprising a storage overpack comprising an inner envelope, wherein the canister is positionable within the storage overpack, and a passive cooling system comprising an inlet vent, an outlet vent, and a duct extending between the inlet vent and the outlet vent. The inlet vent comprises an inlet horn, an inlet exit portion, and a curved portion connecting the inlet horn and the inlet exit portion. 
     Example 25—The nuclear component handling arrangement of Example 24, wherein the outlet vent comprises an outlet horn and an outlet entrance portion. 
     Example 26—The nuclear component handling arrangement of Example 25, wherein the outlet vent further comprises a curved portion extending between the outlet entrance portion and the outlet horn. 
     Example 27—The nuclear component handling arrangement of any of one Examples 24-26, wherein the inlet horn comprises first cross-sectional area, wherein the inlet exit portion comprises a second cross-section area, and wherein the first cross-sectional area and the second cross-sectional area are different. 
     Example 28—The nuclear component handling arrangement of Example 27, wherein the first cross-sectional area is less than the second cross-sectional area. 
     Example 29—The nuclear component handling arrangement of any of one Examples 24-18, wherein the curved portion is a first curved portion, and wherein the passive cooling system comprises a second curved portion. 
     Example 30—The nuclear component handling arrangement of Example 29, wherein the first curved portion comprises a first radius of curvature, wherein the second curved portion comprises a second radius of curvature, and wherein the first radius of curvature and the second radius of curvature are different. 
     Unless specifically stated otherwise as apparent from the foregoing disclosure, it is appreciated that, throughout the foregoing disclosure, discussions using terms such as “processing,” “computing,” “calculating,” “determining,” “displaying,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
     One or more components may be referred to herein as “configured to,” “configurable to,” “operable/operative to,” “adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Those skilled in the art will recognize that “configured to” can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise. 
     Those skilled in the art will recognize that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. 
     In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.,” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together. B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase “A or B” will be typically understood to include the possibilities of “A” or “B” or “A and B.” 
     With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flow diagrams are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. 
     It is worthy to note that any reference to “one aspect,” “an aspect,” “an exemplification,” “one exemplification,” and the like means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases “in one aspect,” “in an aspect,” “in an exemplification,” and “in one exemplification” in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects. 
     Any patent application, patent, non-patent publication, or other disclosure material referred to in this specification and/or listed in any Application Data Sheet is incorporated by reference herein, to the extent that the incorporated materials is not inconsistent herewith. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. 
     The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a system that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Likewise, an element of a system, device, or apparatus that “comprises,” “has,” “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features. 
     In summary, numerous benefits have been described which result from employing the concepts described herein. The foregoing description of the one or more forms has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more forms were chosen and described in order to illustrate principles and practical application to thereby enable one of ordinary skill in the art to utilize the various forms and with various modifications as are suited to the particular use contemplated. It is intended that the claims submitted herewith define the overall scope.