Abstract:
Filtered storage containers for hazardous waste, such as radioactive waste, more particularly plutonium in the form of oxides and salts, are made of stainless steel and include lids which are retained by retaining rings that utilize bayonet or ratchet closures that cooperate with rims that are integral with cans to hold the lids in place. Sealing arrangements are provided that each include an O-ring of a circular cross section which seals radially between the lid and rim, as well as a seal of cruciform cross section, which seal provides compression sealing between the lid and an annular shelf within the rim upon locking the retaining ring to the rim with the bayonet or ratchet fitting.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to storage containers. More particularly, the present invention relates to storage containers especially useful for storing radioactive materials, such as plutonium in the form of oxides and salts, as well as in other forms. 
       BACKGROUND OF THE INVENTION 
       [0002]    Plutonium is a man-made radioactive element which is used as an explosive ingredient in nuclear weapons and as a fuel for nuclear reactors. It has the important nuclear property of being readily fissionable with neutrons and is available in relatively large quantities. Caution must be exercised in handling plutonium to avoid unintentional formation of critical mass. Plutonium in liquid solutions is more apt to become critical than solid plutonium so it is also very important to avoid the unintentional creation of a liquid solution. Since plutonium is considered to be highly carcinogenic, it is important that plutonium in any form be contained and not escape into the surrounding environment where it can be inhaled or otherwise ingested by humans or other living things. Frequently, plutonium oxides and salts are in the form of powders which require very special handling to ensure that particles do not become suspended in the air and that liquid does not come into contact with the powders. Optionally, such containers are vented through high efficiency particulate filters. 
       SUMMARY OF THE INVENTION 
       [0003]    In view of the aforementioned considerations, it is a feature of the present invention to provide new and improved canisters for storage of hazardous materials such as radioactive materials. 
         [0004]    In view of this feature, the container for hazardous materials comprises a can having a closed end and an open end with a locking rim located at the opened end. The locking rim has a shelf therein of a first inner diameter and locking lugs with spaces therebetween disposed in spaced relation to the shelf. A lid having an outer surface and an inner surface is supported on the shelf of the can wherein the outer surface of the lid has a diameter larger than the inner diameter of the shelf. A gasket is disposed between the shelf and the inner surface of the lid and a retaining ring for locking the lid to the gasket has a connection thereon which cooperates with the container to hold the lid in place. 
         [0005]    In a further aspect of the container, the container has a handle mounted on the retaining ring. 
         [0006]    In still a further aspect of the container, the handle is pivoted on the retaining ring to fold toward the lid. 
         [0007]    In still a further aspect of the container, a cavity is defined above the lid by the retaining ring with the handle being U-shaped and pivoted to the retaining ring by pintles which extend into holes in the retaining ring to dispose the handle within the cavity when the handle is folded toward the lid. 
         [0008]    In still a further aspect of the container, the retaining ring has laterally opening drains extending therein to drain liquid from the lid. 
         [0009]    In a further aspect of the container, the container is made of stainless steel having high heat conductivity which can withstand temperatures to about 450° F. 
         [0010]    In still a further aspect of the container, the hazardous waste contained thereby is transuranic material. 
         [0011]    In further aspects of the container, the container includes a gas vent therethrough having a particle filter therein. 
         [0012]    In still a further aspect of the container, the container includes a sampling port containing a one-way valve allowing insertion of a probe through the port to sample fluids within the container. 
         [0013]    In still another aspect of the container, the container is in combination with similar containers of differing heights, widths and volumes with the container being receivable within another container and or receiving another container therein to nest a series of similar containers. 
         [0014]    In still another aspect of the container, the locking ring has a bayonet connection to the can; and 
         [0015]    In still another aspect of the container, the locking ring has a ratchet connection with the can. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0017]      FIG. 1  is a perspective view of a storage container configured in accordance with a first embodiment of the storage container; 
           [0018]      FIG. 2  is a view of three storage containers each having substantially the same configuration as the storage containers in  FIG. 1 , but being of different sizes; 
           [0019]      FIG. 3  is a side elevation of two storage containers of  FIG. 2  with one container stored within the other; 
           [0020]      FIG. 4  is a top view of one of the storage container of  FIGS. 1-3 ; 
           [0021]      FIG. 5  is an exploded view, in perspective, of one of the storage containers as shown in  FIGS. 1-4 ; 
           [0022]      FIG. 6  is a perspective view of a rim used with the storage containers of  FIGS. 1-5 ; 
           [0023]      FIG. 7  is a perspective view of a retaining ring which cooperates with the rim of  FIG. 6 ; 
           [0024]      FIG. 8  is a perspective elevation of a seal shown in  FIG. 5 ; 
           [0025]      FIGS. 9 and 10  provide is a perspective exploded view of a second embodiment of the storage container, which is similar to the first embodiment, but utilizes a locking ring ( FIG. 10 ) having The present invention relates to storage containers. More particularly, the present invention relates to storage containers especially useful for storing radioactive materials, such as plutonium in the form of oxides and salts, as well as in other forms. 
           [0026]      FIG. 11A  is a side view of a fiber optic probe-arrangement of a type preferably used with the containers of  FIGS. 1-10 ; 
           [0027]      FIG. 11B  is a view similar to  FIG. 11A  but showing a snap on detector head; 
           [0028]      FIG. 11C  is a perspective view of a needle probe being inserted through a one way valve in a needle port, and 
           [0029]      FIG. 12  is a view of a graph plotting wavelength (nm) as a function of optical absorption for the sensing tip of the fiber optic cable of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Referring now to  FIG. 1  there is shown a container  10  comprising a can  11  which has a closed end  12  and an open end  14  defining a mouth  15  of the container. The open end  14  has a rim  16  with an inner wall  18  and a lid  20  positioned and supported on the inner wall and optionally having a foldable handle  21  pivoted thereon for lifting the lid  20 . A retaining ring  22  has a bayonet coupling  23  with the inner wall  18  of the rim  16  to retain the lid  20  in place at the open end  14  of the can  11 . A handle  24  is pivoted on the retaining ring  22  by a pair of pintles  25  and  26  positioned in holes  27  and  28  in an inwardly facing wall  30  of the retaining ring  22 . The retaining ring  22  defines a cavity  33  in to which the handle  24  pivots facilitating stacking of the container  10 . 
         [0031]    In accordance with one aspect of the invention, the container  10  optionally has a vent  38  therein with openings  39  therein which exhaust gases and vapors which have been filtered by a particulate filter such as the filter described in U.S. Pat. No. 5,727,707, incorporated in its entirety herein by reference. The retaining ring  22  and the rim  16  have drain openings  42  therethrough which allow liquids, such as water, to flow from the lid  20  so as to not accumulate over the vent  38 , and possibly over time compromise the filter element within the vent. The filter is preferably a carbon-carbon or stainless steel low profile filter which is assembled with a membrane of a material such as GORTEX® so as to exclude water to provide a filter which resists both corrosion and mechanical impacts to the container  10 . In another embodiment of the invention, the can is hermetically sealed without a vent, such as the vent  38 . 
         [0032]    The lid  20  preferably includes a port  44  extending therethrough. The port  44  is sealed by a one-way valve  46  through which a probe  48  is inserted. The probe  48  is attached by a line  50  to a monitor  52  which detects the presence of hydrogen or other explosive gases within the container  10 . 
         [0033]    Referring now to  FIG. 2  there are shown three containers  10 ,  10 ′ and  10 ″, the container  10 ′ being smaller than the container  10  and the container  10 ″ being larger than the container  10 . The containers  10 ,  10 ′ and  10 ″ have substantially the same shape and configuration but are different sizes and may range from about 1 liter to about 70 liters in volume. The containers  10 ,  10 ′ and  10 ″ exemplify a set  60  of the containers. 
         [0034]    Referring now to  FIG. 3 , two containers  10  and  10 ′ are shown with the container  10 ′ nested completely within the container  10 , thus saving considerable storage space prior to using the containers. While nesting of two containers  10  and  10 ′ is shown, the number of containers may be increased with perhaps the only restraint being the weight of the nested containers and perhaps the accessibility of smaller containers. 
         [0035]    Referring now to  FIG. 4  there is shown a top view of a container  10  configured in accordance with the containers of  FIGS. 1-3  and showing the handle  24  pivoted to the folded position in which the handle is completely disposed within the cavity  33  so as to not project above the rim  16  of retaining ring  22 . By so mounting the handle  24  to pivot, the containers  10  can be stacked without interference from the handle which conserves considerable vertical space. Moreover, since the handles are totally within the lateral confines of the container  10 , lateral interference is also avoided increasing lateral storage space. 
         [0036]    Referring now to  FIG. 5  where the various components of the container  10  are shown, the rim  16  is joined to the open end  14  of the can  11  by welding a collar portion  60  to the can  10 . The collar portion  60  may abut the open end  14  of the can  10 , may fit over the outside surface of the can, or may be received within the inside surface of the can. Positioning the open end  14  of the can  10  within the rim  60  is the preferable approach. 
         [0037]    The inner wall surface  18  of the rim  16  has an annular shelf  62  which is abutted by the lid  20 . The lid  20  has an outwardly facing surface  66  and an inwardly facing surface  68  and has a diameter D 3  which is less than the diameter D 1  at the opening of the rim  16 , but greater than the diameter D 2  of the shelf  62 . Consequently, the lid  20  passes through the open end of the rim  16  and rests on the shelf  62 . 
         [0038]    Referring now to  FIG. 6 , the diameter D 1  at the opening of the rim  16  is defined between lugs  70  disposed adjacent the opening of the rim  16 , which lugs  70  have spaces  72  therebetween. The lugs  70  are axially spaced from the shelf to by spaces  74  which are greater than the thickness T of the lid  20 . 
         [0039]    Referring now to  FIG. 7 , the retaining ring  22  has an outer diameter D 4  which is less than the inner diameter D 1  of the rim  16  so that it slides in an axial direction into the cavity  33  formed by the rim and abuts the lid  20 . The retaining ring  22  has second lugs  78  which project radially outwardly therefrom and are spaced from one another by circumferential spaces  80 . The circumferential spaces  80  have an arcuate length greater than the length of the spaces  72  in the rim  16  and are disposed adjacent the bottom of the retaining ring. Moreover, the second lugs  78  of the retaining ring  22  have a height such that the height of the second lugs and the thickness of the lid  20  allows the retaining ring to be rotated so that the second lugs  78  thereon fit beneath the first lugs  70  on the rim  16  providing a bayonet coupling to hold the lid  20  in place on the can  11 . In addition to providing a convenient way to lift the container  10 , the handle  24  also provides a device for rotating the retaining ring  22  to position the second lugs  78  beneath the first lugs  70 . 
         [0040]    Referring now mainly to  FIG. 8 , disposed between the lid  20  and the shelf  62  of the rim  16  is a sealing arrangement  85  which is disposed between a bottom surface  68  of the lid and the shelf  62 . The sealing arrangement  90  may comprise a single seal such as an O-ring of a circular cross section, but it is preferable that the sealing arrangement  85  be comprised of a radial O-ring  86  of a circular cross section and a cruciform shaped, multi-lobed compression O-ring  87 . The radial O-ring  86  seats between the periphery  69  of the lid  20  and the wall  18  of the rim  16 , while the compression O-ring  87  is compressed between the inside surface  68  of the lid and the shelf  62 . The O-ring arrangement  85  provides a positive seal which is maintained during impacts from different and opposing directions. Engagement between the sealing arrangement  85 , rim  16  and the lid  20  results in a leak resistant closure mechanism having leak rate of about 1×10 −8  cc/per second. The seal is preferably made of a fluoroelastomer material such as VITON® rubber and has a sealing life of at least 20 years. 
         [0041]    The container  10  is configured so that there is a 100% interchangeability of the lids  20  for containers of the same size which enhances speed and the assurance of a seal. The sealing is visibly verified when the lugs  78  disappear beneath the lugs  70 . By providing drains, such as the drains  42  which communicate with the space  33  liquid which may accidentally accumulate on the lid  20  by situations such as an inadvertent activation of a fire suppressant system, water is kept from accumulating on the lid  20 . This also minimizes any contamination of a container should radioactive material become spilled, or otherwise deposited, on the exterior of the container. Since the containers  10  utilize stainless steel with high heat conductivity, heat will be dissipated should heat develop within the container. Moreover, the container can withstand external and internal temperatures in excess of 450° F. 
         [0042]    Referring now to  FIGS. 9 and 10 , where a second embodiment  10   a  of the container,  10  is illustrated, the retaining ring  22  has a threaded portion  90  with an external quad-lead thread  92 . The external quad-lead thread  92  meshes with the internal quad-lead thread  94  on a rim  96  defining a mouth  15 ′ of the container  10   a . As the retaining ring  22 ′ is advanced downwardly by screwing the retaining ring into the quad-lead threads  94  the compression lid  20  is urged down between the radial O-ring  86  and the wall  97  of the rim  96 . 
         [0043]    In the embodiment  10   a , the container of  FIGS. 9 and 10 , the bayonet coupling  23  of  FIGS. 1-8  is replaced by first ratchet couplings  100  and  102  on the rim  102  deposed at the open end  14 ′ of the container  10   a  and second ratchet couplings  104  and  106  disposed on the retaining ring  22 ′. The first ratchet couplings  100  and  101  are opposed segments of a circle with teeth  110  and  111  that have ramped ridges defining valleys  112  and  113  therebetween. The valleys  112  and  113  receive detents  115  and  117  that project radially from the retaining ring  22 ′. The detents are preferably spring projected, ball detents mounted in hubs  120  and  122  of hinges  124  and  126  which rotatably support opposed ends  128  and  130  of a U-shaped handle  132 . The hubs  120  and  124  have actuators  134  and  136  which allow the ball detents  115  and  117  to retract into the hubs so that the retaining ring  22 ′ can be rotated to allow removal of the compressing lid  20 ′ using the lifting handle  21  thereon. 
         [0044]    Referring now to  FIGS. 11A, 11B, 11C and 12 , an embodiment of a hydrogen gas detector  150  is shown. The hydrogen gas detector  150  has a fiber optic lead  152  that preferably has a snap-on detector head  154  ( FIG. 11A ). The snap-on detector head  154  is receivable in an opening  156  in the end of a needle probe  160  ( FIG. 11C ) having a needle shank  162  that penetrates the one-way valve  46  for sampling gas in the containers  10  and  10   a . The one-way valve  46  in this instance is a hermetic seal, such as the seal used in U.S. Pat. No. 6,395,050, issued May 28, 2002, assigned to the assignee of the present invention, Nuclear Filter Technology and incorporated herein in its entirety by reference, through which seal  46  the shank  162  of the needle passes. In the present invention the seal  46  is preferably integral with the lid  20  as is shown in  FIGS. 1, 4 and 5 . However, the seal  46  may be incorporated in a vent structure for the housing or in a separate plug structure. The amount of hydrogen detected alters optical absorption through a tungsten tri-oxide glass layer  166  according to the graph of  FIG. 12  plotting optical absorption as a function of the wavelength of light reflected from the tungsten tri-oxide layer  166 . 
         [0045]    From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing form the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 
         [0046]    The following text is a compliance report created as a result of the performance tests performed on a New Generation Standard Nuclear Material Container consistent with the invention herein. The standard for success in the performance test conducted on the Tested Device was defined by the requirements of Department of Energy Manual §441, Nuclear Material Packaging Manual, DOE M 441.1-1 approved Mar. 7, 2008, certified Nov. 18, 2010. The Tested Device met or exceeded the requirements of the performance test.