Abstract:
Systems produce desired isotopes through irradiation in nuclear reactor instrumentation tubes and deposit the same in a robust facility for immediate shipping, handling, and/or consumption. Irradiation targets are inserted and removed through inaccessible areas without plant shutdown and placed in the harvesting facility, such as a plurality of sealable and shipping-safe casks and/or canisters. Systems may connect various structures in a sealed manner to avoid release of dangerous or unwanted matter throughout the nuclear plant, and/or systems may also automatically decontaminate materials to be released. Useable casks or canisters can include plural barriers for containment that are temporarily and selectively removable with specially-configured paths inserted therein. Penetrations in the facilities may limit waste or pneumatic gas escape and allow the same to be removed from the systems without over-pressurization or leakage. Methods include processing irradiation targets through such systems and securely delivering them in such harvesting facilities.

Description:
PRIORITY STATEMENT 
     This application is a continuation-in-part of, and claims priority under 35 U.S.C. §120 to, co-pending application Ser. No. 13/477,244 filed May 22, 2012, the contents of said application being incorporated by reference herein in their entirety. 
    
    
     GOVERNMENT SUPPORT 
     This invention was made with Government support under contract number DE-FC52-09NA29626, awarded by the U.S. Department of Energy. The Government has certain rights in the invention. 
    
    
     BACKGROUND 
     Elements, and specific isotopes thereof, may be formed by bombarding parent materials with appropriate radiation to cause a conversion to desired daughter isotopes. For example, precious metals and/or radioisotopes may be formed through such bombardment. Conventionally, particle accelerators or specially-designed, non-commercial test reactors are used to achieve such bombardment and produce desired isotopes in relatively small amounts. 
     Radioisotopes have a variety of medical and industrial applications stemming from their ability to emit discreet amounts and types of ionizing radiation and form useful daughter products. For example, radioisotopes are useful in cancer-related therapy, medical imaging and labeling technology, cancer and other disease diagnosis, and medical sterilization. 
     Radioisotopes having half-lives on the order of days or hours are conventionally produced by bombarding stable parent isotopes in accelerators or low-power, non-electricity-generating reactors. These accelerators or reactors are on-site at medical or industrial facilities or at nearby production facilities. Especially short-lived radioisotopes must be quickly transported due to the relatively quick decay time and the exact amounts of radioisotopes needed in particular applications. Further, on-site production of radioisotopes generally requires cumbersome and expensive irradiation and extraction equipment, which may be cost-, space-, and/or safety-prohibitive at end-use facilities. 
     SUMMARY 
     Example embodiments include systems that allow irradiation targets to be irradiated in a nuclear reactor and deposited in a harvestable configuration without direct human interaction or discontinuation of power-producing activities. Example systems include devices that insert and remove irradiation targets through areas that cannot be directly and safely accessed by humans during plant operation via paths that connect to instrumentation tubes in the nuclear reactor inside the access barrier; these systems include accessible end-points that store desired produced isotopes for handling and/or shipping. The end points can be casks that are securely connected to the system through a sealed channel to prevent migration of waste and/or permit pneumatic forcing of targets through the system and into the casks as well as to exhaust systems that scrub excess gasses for safe release or storage. Example embodiments also include casks with multiple levels of containment that can be breached only for deposition of irradiation targets but otherwise seal. For example, an outer cask can be sealed with a removable cask plug and contain a canister sealed in an internal volume of the outer cask to prevent migration of any matter to an outside of the cask when sealed. Various holes, ports, and/or receptacles in the outer cask and canister can permit only configured irradiation target transport structures to enter these structures and deposit irradiation targets within the cask, while also permitting waste or pneumatic gasses to be removed from the cask without over-pressurization or leakage. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       Example embodiments will become more apparent by describing, in detail, the attached drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the terms which they depict. 
         FIG. 1  is an illustration of a conventional commercial nuclear reactor. 
         FIG. 2  is an illustration of an example embodiment irradiation target system. 
         FIG. 3  is an illustration of an example embodiment irradiation target system. 
         FIG. 4  is an illustration of an example embodiment cask tube. 
         FIG. 5  is a sectional illustration of an example embodiment harvesting cask. 
         FIG. 6  is a detail illustration of an example embodiment harvesting cask. 
     
    
    
     DETAILED DESCRIPTION 
     This is a patent document, and general broad rules of construction should be applied when reading and understanding it. Everything described and shown in this document is an example of subject matter falling within the scope of the appended claims. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use example embodiments. Several different embodiments not specifically disclosed herein fall within the scope of the appended claims; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element is referred to in a spatial or physical relationship, as being “connected,” “coupled,” “mated,” “attached,” or “fixed,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, for example, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange routes between two devices, including intermediary devices, networks, etc., connected wirelessly or not. 
     As used herein, the singular forms “a”, “an” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise with words like “only,” “single,” and/or “one.” It will be further understood that terms like “have,” “having,” “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, steps, operations, elements, ideas, and/or components, but do not themselves preclude the presence or addition of one or more other features, steps, operations, elements, components, ideas, and/or groups thereof. 
     It should also be noted that the structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from the single operations described below. It should be presumed that any embodiment having features and functionality described below, in any workable combination, falls within the scope of example embodiments. 
       FIG. 1  is an illustration of a conventional nuclear reactor pressure vessel  10  usable with example embodiments and example methods. Reactor pressure vessel  10  may be, for example, a 100+MWe commercial light water nuclear reactor conventionally used for electricity generation throughout the world. Reactor pressure vessel  10  is conventionally contained within an access barrier  411  that serves to contain radioactivity in the case of an accident and prevent access to reactor  10  during operation of the reactor  10 . As defined herein, an access barrier is any structure that prevents human access to an area during operation of the nuclear reactor due to safety or operational hazards such as radiation. As such, access barrier  411  may be a containment building sealed and inaccessible during reactor operation, a drywell wall surrounding an area around the reactor, a reactor shield wall, a human movement barrier preventing access to instrumentation tube  50 , etc. 
     A cavity below the reactor vessel  10 , known as a drywell  20 , serves to house equipment servicing the vessel such as pumps, drains, instrumentation tubes, and/or control rod drives. As shown in  FIG. 1  and as defined herein, at least one instrumentation tube  50  extends into the vessel  10  and near, into, or through core  15  containing nuclear fuel and relatively high levels of neutron flux and other radiation during operation of the core  15 . As existing in conventional nuclear power reactors and as defined herein, instrumentation tubes  50  are enclosed within vessel  10  and open outside of vessel  10 , permitting spatial access to positions proximate to core  15  from outside vessel  10  while still being physically separated from innards of the reactor and core by instrumentation tube  50 . Instrumentation tubes  50  may be generally cylindrical and may widen with height of the vessel  10 ; however, other instrumentation tube geometries may be encountered in the industry. An instrumentation tube  50  may have an inner diameter of about 1-0.5 inch, for example. 
     Instrumentation tubes  50  may terminate below the reactor vessel  10  in the drywell  20 . Conventionally, instrumentation tubes  50  may permit neutron detectors, and other types of detectors, to be inserted therein through an opening at a lower end in the drywell  20 . These detectors may extend up through instrumentation tubes  50  to monitor conditions in the core  15 . Examples of conventional monitor types include wide range detectors (WRNM), source range monitors (SRM), intermediate range monitors (IRM), and traversing Incore probes (TIP). Access to the instrumentation tubes  50  and any monitoring devices inserted therein is conventionally restricted to operational outages due to containment and radiation hazards. 
     Although vessel  10  is illustrated with components commonly found in a commercial Boiling Water Reactor, example embodiments and methods are useable with several different types of reactors having instrumentation tubes  50  or other access tubes that extend into the reactor. For example, Pressurized Water Reactors, Heavy-Water Reactors, Graphite-Moderated Reactors, etc. having a power rating from below 100 Megawatts-electric to several Gigawatts-electric and having instrumentation tubes at several different positions from those shown in  FIG. 1  may be useable with example embodiments and methods. As such, instrumentation tubes useable in example methods may be at any geometry about the core that allows enclosed access to the flux of the nuclear core of various types of reactors. 
     Applicants have recognized that instrumentation tubes  50  may be useable to relatively quickly and constantly generate short-term radioisotopes on a large-scale basis without interfering with an operating or refueling core  15 . Applicants have further recognized a need to generate short-term radioisotopes and remove them from within access barrier  411  quickly, without having to shut down an operating nuclear reactor to access an area within access barrier  411 . Example methods include inserting irradiation targets into instrumentation tubes  50  and exposing the irradiation targets to the core  15  while operating or producing radiation, thereby exposing the irradiation targets to the neutron flux and other radiation commonly encountered in the operating core  15 . The core flux over time converts a substantial portion of the irradiation targets to a useful mass of radioisotope, including short-term radioisotopes useable in medical applications. Irradiation targets may then be withdrawn from the instrumentation tubes  50 , even during ongoing operation of the core  15 , and removed for medical and/or industrial use. 
     Applicants have further recognized a need for a maximized amount of radioisotope production within instrumentation tubes  50 , but also identified that such need can be limited by handling and shipping requirements. Produced isotopes can be themselves radioactive or include radioactive contamination from exposure to neutron flux, such that regulatory-approved handling methods and shipping casks must be used in connection with produced isotopes as well as precautions to strip out contamination and off-gasses produced in example systems. The requisite safety, handling, and shipping protocols may require an undue amount of space, add handling delay to harvesting and commercial exploitation, and/or be difficult to implement in access-restricted spaces. Recognizing these problems for mass producing desired isotopes in instrumentation tubes of commercial nuclear reactors, the applicants have developed solutions to these problems, some of which are uniquely enabled by example embodiments discussed below. 
       FIG. 2  is a schematic drawing of an example embodiment irradiation target delivery and retrieval system  1000  having a penetration pathway, a loading/offloading system, and a drive system.  FIG. 2  illustrates various components of example system  1000  in a loading configuration, another example configuration of which is described in US Patent Publication 2013/0170927, titled “Systems and Methods for Processing Irradiation Targets Through a Nuclear Reactor,” filed Dec. 28, 2011, said application incorporated by reference herein in its entirety. As shown in  FIG. 2 , example embodiment irradiation target delivery and retrieval system  1000  may include or use one or more elements to facilitate irradiation target loading, irradiation, and harvesting in a timely, automatic, and/or consumption-enhancing manner. System  1000  includes a penetration pathway that provides a path from outside access barrier  411  to instrumentation tube  50  for one or more irradiation targets, a loading/offloading system that permits new irradiation targets to be inserted and irradiated targets to be harvested outside access barrier  411 , and a drive system that moves irradiation targets between instrumentation tube  50  and loading/offloading in example embodiment system  1000 . 
     A penetration pathway in example embodiment system  1000  provides a reliable path of travel for irradiation targets  250  between an accessible location, such as an offloading or loading area outside access barrier  411  into one or more instrumentation tubes  50 , so irradiation targets  250  can move within the pathway to a position in or near an operating nuclear core  15  for irradiation. Example pathways can include many delivery mechanisms used alone or in combination, including tubing, frames, wires, chains, conveyors, etc. in example embodiment system  1000  to provide a transit path for an irradiation target between an accessible location and an operating nuclear core. 
     Penetration tubing  1100  may be flexible or rigid and sized to appropriately permit irradiation targets  250  to enter into and/or through penetration tubing  1100  and navigate various structures and penetrations in and within access barrier  411 . Penetration tubing  1100  may be continuously sealed or include openings, such as at connecting junctions. Penetration tubing  1100  may junction with other tubes and/or structures and/or include interruptions. One possible advantage of penetration tubing  1100  being sealed and securely mating at junctures and/or with any terminal/originating points is that penetration tubing  1100  better maintains pneumatic pressure that can be used for target withdrawal, and also may provide additional containment for irradiation targets  250  and any products formed as irradiation products in example embodiment system  1000 . 
     Penetration tubing  1100  used in example embodiment system  1000  provides a route from an origin at loading junction  1200 , where irradiation targets may enter/exit penetration tubing  1100  outside of access barrier  411 . As shown in  FIG. 2 , for example, penetration tubing  1100  leads irradiation targets  250  from loading junction  1200  to access barrier  411 , which may be, for example, a steel-lined reinforced concrete containment wall or drywell wall or any other access restriction in conventional nuclear power stations. 
     Penetration pathways usable in example embodiment system  1000  provide a route through access barrier  411  and to reactor vessel  10  where irradiation targets  250  may enter an instrumentation tube  50 . For example, as shown in  FIG. 2 , penetration tubing  1100  penetrates access barrier  411  and extends to instrumentation tubes  50 . Penetration tubing  1100  may pass through an existing penetration in access barrier  411 , such as an existing TIP tube penetration, or may use a new penetration created for penetration tubing  1100 . Penetration tubing  1100  negotiates or passes through any other objects inside of access barrier  411  before reaching instrumentation tube  50 . 
     An annular reactor pedestal  412  may be present in a drywell  20  beneath reactor  10 , and penetration tubing  1100  is shown in  FIG. 2  passing through a penetration in pedestal  412 . It is understood that penetration pathways may follow any number of different courses and negotiate different obstacles in different reactor designs aside from the specific example path shown with penetration tubing  1100  in  FIG. 2 . Similarly, penetration pathways need not be consistent or uniform; for example, penetration tubing  1100  may terminate on either side of, and be connected to, a penetration in pedestal  412  to permit irradiation targets  250  to pass through the penetration between penetration tubing  1100 . 
     Penetration pathways useable in example embodiment system  1000  may terminate at or within an instrumentation tube  50 . As shown in  FIG. 2 , penetration tubing  1100  terminates at a flange  1110  at a base of instrumentation tube  50 , permitting irradiation targets  250  to pass from penetration tubing  1100  into instrumentation tube  50 . Similarly, penetration tubing  1100  may join with an indexer that provides access to several instrumentation tubes  50  from a single penetration through access barrier  411  and/or pedestal  412 . Such a system is described in US Patent Publication 2013/0315361 titled “Systems and Methods for Processing Irradiation Targets Through Multiple Instrumentation Tubes in a Nuclear Reactor,” filed May 22, 2012, said application incorporated herein by reference in its entirety. 
     The present invention is directed to systems for producing desired isotopes in nuclear reactors that use a harvesting facility providing automatic/remotely-controllable containment to the produced isotopes for ready handling, shipping, and/or commercialization. Some example embodiments of casks and delivery systems falling within this invention are described below, with the understanding that the specific locations, harvesting structures, delivery path arrangements, and plant types shown in example embodiment systems can be varied across a wide variety of configurations, based on available space, plant operating parameters, isotope properties, regulatory compliance, etc. 
       FIG. 3  is an illustration of an example embodiment system  1000  arranged inside of a containment structure for a nuclear plant. As shown in  FIG. 3 , diverter  630 , driving mechanism  1300 , indexer  600 , and harvesting cask  1290  can all be located just inside of a containment building in the nuclear plant. Penetration pathway  1100   a/b  can provide access through an access barrier  411  in containment and to an instrumentation tube  50  ( FIG. 2 ). In the example embodiment system of  FIG. 3 , diverter  630  may be a three-way diverter  630 , similar to that in US Patent Publication 2013/0177125 titled “SYSTEMS AND METHODS FOR MANAGING SHARED-PATH INSTRUMENTATION AND IRRADIATION TARGETS IN A NUCLEAR REACTOR” filed Dec. 10, 2012, by Heinold et al., which is herein incorporated by reference in its entirety. In  FIG. 3 , diverter  630  may select between cask tube  1291 , TIP tubing  300 , and penetration pathway  1100 . Cask tube  1291  may function similarly to provide irradiation targets drain produced isotopes through example embodiment system  1000 . That is, example embodiment system  1000  may operate similarly to other configurations described in  FIG. 2  and in the incorporated documents, except with TIP drive  1300  inside of containment and diverter  630  serving as a loading junction inside access barrier  411 , which may be containment. 
     As shown in  FIG. 3 , example embodiment irradiation target delivery and retrieval system  1000  may include several harvesting structures and arrangements in addition to harvesting cask  1290  in order to facilitate produced isotope harvesting continuously, with minimal risk or human intervention, and/or in a manner conducive to ready commercialization. For example, structures and arrangements for fail-safe and air-tight deposition of irradiation targets ready for commercial use in a variety of containers can be implemented in connection with example system  1000 . 
     In  FIG. 3 , cask tube  1291  provides a pathway for irradiated irradiation targets to pass out of diverter  630  and may include one or more counters  1295  that detect an exact number, amount, or activity or irradiated irradiation targets that exit through cask tube  1291 , to ensure proper accounting of irradiation target within system  1000  and/or determination of when cask  1290  is nearing fullness. 
     Cask tube  1291  may include an exhaust line  1281  connected to cask tube  1291  in whole or part. Exhaust line  1281  may allow produced or entrained gas, such as a pneumatic fluid used to drive irradiation targets, to safely exit system  1000  without becoming trapped in or pressurizing harvesting cask  1290 . Exhaust line  1281  can include one or more filters  1280 ; for example, filters  1280  may be high-grade HEPA filters capable of screening out radioactive particulate matter. Exhaust line  1281  may be bifurcated and drawn through two HEPA filters  1280  in parallel as shown in  FIG. 3 . 
     Several differential flow gauges  1282  on either side of each filter  1280  may monitor pneumatic exhaust flow and ensure proper flow rates for effective operation of filter  1280 . Differential flow gauges  1282  may be coupled or operable with one or more valves  1283  (only one is shown in  FIG. 3 , but it is understood that multiple flow valves  1283  could be on each segment of exhaust line  1281  on both sides of each HEPA filter  1280 ). Valves  1283  can be selectively opened or closed to desired degrees to maintain even exhaust flow through each filter  1280  and/or to seal off exhaust line  1281  if necessary, such as in an emergency situation. 
     Exhaust line  1281  can run outside of example embodiment system  1000  and connect with existing plant exhaust systems (not shown) at atmospheric pressure. In this way exhaust from line  1281  can be filtered of any radioactive particulates by filters  1280  and subsequently processed by plant exhaust system normally. 
     Cask tube  1291  may include an insertion tube assembly  1292  at its terminal portion where meeting harvesting cask  1290 . Insertion tube assembly  1292  may be specially configured to mate with structures in harvesting cask  1290  to ensure reliable delivery of produced isotopes for storage and commercialization in cask  1290 . For example, insertion tube assembly  1292  may extend for the final twenty feet of cask tube  1291  and descend downward into harvesting cask  1290  at an angle. Insertion tube assembly  1292  may have separate paths for irradiation targets and exhaust flowing into/out of harvesting cask  1290 ; for example, insertion tube assembly  1292  may include an exhaust path that flows directly or exclusively into exhaust line  1281  from harvesting cask  1290  to ensure no over-pressurization or buildup of waste gasses in harvesting cask  1290 . 
     Insertion tube assembly  1292  may include a motor, lift, or other automated movement mechanism that can align and engage insertion tube assembly  1292  with harvesting cask  1290  or any other desired end point. For example, insertion tube assembly  1292  may be moved between several different casks  1290  or other end facilities based on contents discharged through example embodiment system  1000 . Such movement and selection of destinations may be made automatically or remotely by users controlling a motor in insertion tube assembly  1292 . 
       FIG. 4  is an illustration of an example embodiment cask tube  1291  that may be useable with multiple casks and/or destinations based on target properties. As shown in  FIG. 4  one or more stops  1298  may be inserted into cask tube  1291  at desired positions to separate out a certain population of irradiation targets. For example, two stops  1298  may be inserted in cask tube  1291  at a distance d that corresponds to a length of leader spheres  251  used in an example embodiment system  1000  ( FIG. 3 ). Leader spheres  251  may then be emptied out of cask tube  1291  via gravity or pneumatic force into a separate cask or other facility. For example, a motor associated with insertion tube assembly  1292  may align with a leader sphere receptacle, then only the front spacer  1298  and leader spheres  251  may be emptied into this cask, and remaining irradiated irradiation targets  250  may be retained in cask tube  1291  via back stop  1298 . Insertion tube assembly may then be directed to harvesting cask  1290  ( FIG. 3 ) and back stop  1298  removed such that irradiation targets  250  can flow to harvesting cask  1290 . Of course, other arrangements, distances d, and final destinations for any sub-populations of irradiation targets useable with example systems may be used in connection with example embodiments. 
     One or more radiation monitors  1285  may be placed on or around harvesting cask  1290  in order to measure radiation levels and indicate if any leakage is occurring from or between harvesting cask  1290  and cask tube  1291 . Radiation monitors may also be used in connection with filters  1280  to ensure no leakage or other alarming radioactive buildup at any point through example embodiment system  1000 . 
       FIG. 5  is a section illustration of an example embodiment harvesting cask  1290 . As shown in  FIG. 5 , insertion tube assembly  1292  ( FIG. 3 ) can include an outer insertion cylinder and one or more linear motors  1294  that surrounds and axially drives an inner insertion tube  1293 , in which irradiation targets may be transported for harvesting. Linear motor  1294  may securely mount on an insertion receptacle  1261  of harvesting cask  1290  to extend insertion tube  1293  to a hole dimensioned to receive insertion tube  1293  at a specific angle of attack, permitting reliable insertion as well as aiding movement of irradiation targets therein by gravity. 
     Insertion tube  1293  has sufficient length and material strength to extend through harvesting cask  1290  and penetrate a harvesting canister  1260  secured within harvesting cask  1290 . For example, insertion tube  1293  may pass into a sealable canister port  1265  in a top portion of canister  1260  that is shaped to receive insertion tube  1293  at the angle of attack. Harvesting cask  1290  can be a variety of shapes and sizes, with insertion tube  1293  correspondingly configured to pass into cask  1290  and deposit into a canister therein. Harvesting cask  1290  can include a handle (not shown) or other handling features that permit movement and shipping of harvesting cask  1290 . Harvesting cask  1290  may further be modular, with durable sections that house irradiated irradiation targets being removable for shipping without transporting the entire cask  1290 . Harvesting cask  1290  and such portions thereof may be fabricated of sufficiently reinforced materials and dimensions to comply with regulatory shipping requirements for radioactive materials, if harvested isotopes are radioactive. 
     Access to harvesting canister may be selectively available through movement of a cask sealing plug  1297 . As shown in  FIG. 5 , when cask sealing plug  1297  is raised in its open position, insertion tube  1293  may pass to and into harvesting canister  1260  via insertion receptacle  1261  and canister port  1265 . If cask sealing plug  1297  is lowered atop harvesting canister  1260  to meet corresponding surfaces of harvesting cask  1290 , insertion tube  1261  will be unable to pass beyond insertion receptacle  1261 . Cask sealing plug  1297  can be sealed in the lowered position for removal and shipping with canister  1260  and harvestable isotopes stored therein. 
     Canister  1260  can be any sealed structure capable of safely containing harvestable irradiated irradiation targets in an air-tight, atmospheric state. Canister  1260  may seat directly into harvesting cask  1290  as shown in  FIG. 5 , and be removable therefrom for harvesting at desired end facilities. Harvesting may be accomplished in several ways; for example, a bottom of canister  1260  may be angled and detachable through rotation from the remainder of canister  1260 , permitting ready removal of irradiation targets therein through such a bottom. 
     Canister  1260  includes a sealable mechanism for receiving irradiation targets while maintaining a seal and without direct human interaction. For example, canister port  1265 , circled in Detail A of  FIG. 5 , can provide such sealable entry for irradiated irradiation targets into canister  1260 . Once canister  1260  is filled with desired produced isotopes in automated system  1000  and sealed within cask  1290 , cask  1290  can be readily cabled or rolled on tracks through a personnel hatch in access barrier  411 , or otherwise delivered if outside access barrier  411 . A transport cart, tug, and/or pallet jack or other moving devices can deliver cask  1260  to a shipping dock. At the dock, cask  1260  can be shipped or prepared for shipping by adding any regulatory-required structures or markers not already present on cask  1260  for shipping. 
       FIG. 6  is a detail illustration of Section A of canister port  1265  from  FIG. 5 . As shown in  FIG. 6 , canister port  1265  can selectively allow solid or liquid irradiation targets to enter canister  1260  from insertion tube  1293   a  while allowing a driving pneumatic medium or other waste gas to be vented from canister  1260 . Canister port  1265  may also provide a seal to canister  1260  except when specifically actuated for filling with insertion tube  1293 . For example, insertion tube  1293  may include two distinct passages—a depositing path  1293   a  and an exhaust path  1293   b . The different paths may run side-by-side or concentrically, for example, via two different tubes in insertion tube  1293 . 
     Depositing path  1293   a  may be sized and otherwise configured to convey irradiated irradiation targets into canister  1260 . As shown in  FIG. 6 , depositing path  1293   a  may open into canister port  1265 , which is itself open to the internals of canister  1260 , and harvested irradiation targets may fall, under gravity or a driving pneumatic medium, into canister  1260  as shown by an arrow. Exhaust path  1293   b  may similarly be in pneumatic communication with an internal volume of canister  1260  opposite where depositing path  1293   a  opens into canister  1260 . Excess gas may flow through canister port  1260  and into exhaust path  1293   b , shown by an arrow, to avoid pressurization of canister  1260  and/or accumulation of unwanted waste gasses. Exhaust path  1293   b  may be exclusively connected to exhaust line  1281  that exhausts to a plant exhaust system at atmospheric pressure, encouraging all gas introduced through depositing path  1293   a  to flow back out of exhaust path  1293   b . Non-gaseous irradiation targets may be unaffected by this pressure differential after being driven into canister  1260 , allowing the harvested irradiation targets to remain sealed in canister  1260  while gas is exhausted therefrom. 
     Canister port  1265  may further include a biased plunger  1266  that is driven by one or more springs  1267  toward a ring-type seal  1268  about an entrance to canister port  1265 . When insertion tube  1293  is withdrawn from canister port  1265 , such as during shipping and/or non-filling times, springs  1267  may force plunger  1266  up to contact seal  1268  with sufficient force to seal canister  1260  and prevent leakage of gasses or other materials therein during shipping and handling. When insertion tube  1293  is negotiated through cask  1290  ( FIG. 5 ) and into canister port  1265 , an end of insertion tube  1293  may drive plunger  1267  down to a base as shown in  FIG. 6 , opening pathways in canister port  1265  for irradiation targets to flow from depositing path  1293   a  into canister  1260 . 
     For example, exhaust path  1293   b  may be slightly longer and narrower than depositing path  1293   a  and contact plunger  1266  to drive plunger  1266  down into the open position while depositing path  1293   a  is shorter and open to innards of canister  1260 . In this way depositing path  1293  may remain unobstructed and able to rapidly deposit irradiation targets into canister  1260 , while exhaust path  1293   b  can only convey gasses out of canister  1260  through an opening not blocked by plunger  1266 . Of course, any other selective biasing mechanisms can be used to depress plunger  1266  against springs  1267  when insertion tube  1293  is ready to deposit irradiation targets for harvest in canister  1260 . 
     As shown in  FIG. 5 , cask sealing plug  1297  can be withdrawn to permit insertion tube  1293  access to canister port  1265 . Although canister port  1265  may be seal-sealing and configured to permit excess gas to flow in a closed path back out of insertion tube  1293  to an exhaust system, hood  1262  may provide a secondary seal to guard against escape of unscrubbed pneumatic gasses or waste gasses in example embodiment systems. Hood  1262  may be bolted or otherwise removably secured to harvesting cask  1290  about a top where cask sealing plug  1292  may enclose harvesting cask  1290 . 
     As shown in  FIG. 5 , cask sealing plug  1297  may seat within hood  1262  and be drawn through a top opening of hood  1262  by a cask plug lift  1296 . Cask plug lift  1296  may include several redundant motors supported from hood  1262  that are configured to securely join to and precisely and without fail lift and lower cask sealing plug  1292  with necessary force. Cask plug  1297  may seat against a continuous flange  1263  in a top of hood  1262  to provide a secondary barrier to any material that may escape from canister  1260 , cask  1290 , and/or insertion tube  1293  during delivery of irradiated irradiation targets to harvesting cask  1290 . Flange  1263  may include an elastic seal material around its entire lower surface to enhance air-tightness between flange  1263  and cask sealing plug  1292 . 
     Hood  1262  may further include one or more stop pins (not shown) extending inward from its perimeter to block and hold cask plug  1297  in the event of cask plug lift  1296  failing. For example, a pair of opposite stop pins may be engaged when cask sealing plug  1297  is drawn against flange  1263  just below a bottom of cask plug  1297 ; these pins may reduce any risk that cask plug  1297  may fall and crush insertion tube  1293  during insertion and delivery. Further, one or more adjustment screws  1264  on top of flange  1263  may provide a desired amount of clearance or pressure between cask plug  1297  and flange  1263  by setting a maximum level that cask plug lift  1296  can raise cask plug  1297 . Hood  1262  may further include its own exhaust vent (not shown) that flows into exhaust line  1281  or filters  1280  to eliminate any buildup of gasses that may escape into hood  1262  but be unable to escape past the secondary seal formed by plug  1297  and flange  1263 . 
     Insertion receptacle  1261  may provide a passage through hood  1262  at a specific angle and orientation of insertion tube  1293 . Insertion receptacle may be sized to receive insertion tube  1293  without leakage from hood  1262 ; for example insertion receptacle  1261  may further include an elastic seal or surrounding gasket that permits insertion tube  1293  to pass therethrough with minimized leakage. An angle of insertion receptacle  1261  can match an angle of attack required to actuate canister port  1265  for depositing irradiated targets therein. In this way, only when canister port  1265  and insertion receptacle  1261  are properly aligned and traversed by a properly configured structure like insertion tube  1293  can targets successfully be emptied into canister  1260 , preventing accidental or spurious deposits. 
     In operation, cylinder and motor  1294  may align with insertion receptacle  1261  such that insertion tube  1293  is aligned with an opening in insertion receptacle  1261 . Cask plug lift  1296  can attach to, or may be already secured to, case sealing plug  1297  on a top of harvesting cask  1290 , and cask plug lift  1296  may then lift cask plug  1297  up to flange  1263  of hood  1262 . Cask sealing plug  1297  and flange  1263  may then form a seal above canister  1260 , stopped at a desired position by adjustment screws  1264 , and any desired stop pins or other safety mechanisms can be engaged to avoid accidental dropping of cask plug  1297 . Motor  1294  may then drive insertion tube  1293  through insertion receptacle  1261  and down into canister port  1265 . Insertion tube actuates canister port  1265 , providing sealed a path into canister  1260 . Through pneumatic and gravitational forces in example embodiment systems, irradiation targets emptied from reactors where they have been converted into desired daughter products may then flow into canister  1260  through insertion tube  1293 . Any undesired gasses can be vented into exhaust lines through a pressure differential. 
     Once all targets have been deposited in canister  1260 , insertion tube may be withdrawn by motor  1294 . The withdrawing can seal canister  1260 , and cask sealing plug may then be lowered and sealed in cask  1290  following the withdrawal. If canister  1260  is full or has a desired amount of produced isotopes stored therein, as potentially determined by sensors  1295  ( FIG. 3 ), harvesting cask  1290  may be removed from containment and shipped to a particular end facility. Harvesting cask  1290  may be partially deconstructed in this process; for example, only an inner portion of cask  1290  surrounding canister  1260  may be removed and shipped, or harvesting cask  1290  may be removed and shipped if hood  1262  is removed and cask plug lift  1296  disengaged from plug  1297 . Each of these actions may be accomplished remotely and without direct human interaction to facilitate minimal entry into containment and radiation exposure. 
     Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, the locations, numbers, and dimensions of harvesting casks are not limited to the specific systems shown and described in the figures—other systems using multiple casks outside containment for reliably harvesting irradiation targets are equally useable as example embodiments and fall within the scope of the claims. Furthermore, it is understood that example systems and methods are useable in any type of nuclear plant with access barriers that prevent unlimited access to the reactor, including known light water reactor designs, graphite-moderated reactors, and/or molten salt reactors, as well as any other nuclear plant design. Such variations are not to be regarded as departure from the scope of the following claims.