Patent Description:
<CIT> discloses a containment cask for safely transporting and storing radioactive hazardous waste without a payload liner.

<CIT> discloses a payload liner inside a container and mounted to the container wall by tension rods.

There is a need for an inexpensive transportation and storage containment cask for a small modular Type B fissile waste that is capable of shipping and storing at least the following contents: (a) DOE-EM legacy wastes, including contact-handled (CH) and remote-handled (RH) TRU wastes in U. standard <NUM>-gal (i.e. approximately <NUM> I), <NUM>-gal (i.e. approximately <NUM> I) and <NUM>-gal (i.e. approximately <NUM> I) drums and other containers of similar or smaller dimensions; and (b) Canada deuterium uranium (CANDU) spent fuel in basket configurations from the Atomic Energy of Canada Limited (AECL) facilities.

Any such containment cask must follow the extensive applicable regulations for the transport and storage of fissile and radioactive contents in the U. and Canada.

Embodiments of containment casks and methods are provided for safely transporting and storing drums that contain radioactive hazardous waste.

The invention is a containment cask for safely transporting and storing radioactive hazardous waste in a dry air environment. The cask comprises a single drum containing the radioactive hazardous waste, a sealed and shielded containment vessel containing the drum, and an outer container as defined in claim <NUM>.

The outer container can take a plurality of forms. It can be in the form of an outer shield vessel (OSV) made from iron to provide further shielding. This outer container is appropriate for a drum having higher activity waste. The outer container can also be in the form of an overpack assembly that adds protection for hypothetical accident conditions (e.g., free drop, puncture, and fire), but adds little in terms of shielding. This outer container is appropriate for a drum having lower activity waste.

Other vessels, apparatus, methods, apparatus, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description.

<FIG> is a perspective view of a first embodiment of a containment cask, denoted by reference numeral <NUM>, with cutaway showing an outer shield vessel <NUM> (OSV; outer container) that contains a common containment vessel (CCV) <NUM> that is designed to contain a single stainless steel drum <NUM> (<FIG>) having radioactive hazardous waste, including but not limited to, non-compliant remote handled transuranic (RH-TRU) waste (e.g., RH-TRU waste containing items that are not permitted by the waste isolation pilot plate (WIPP) acceptance criteria, such as aerosol cans, small liquid containers, etc.), Canada deuterium uranium (CANDU) waste, radioactive debris, experimental spent nuclear fuel, irradiated fissile materials, nuclear fuel debris, high level waste (HLW), greater than Class C waste (GTCC), etc. The drum <NUM> can be any one of the following: a U. standard <NUM>-gallon (i.e. approximately <NUM> I) drum 16a (<FIG>), <NUM>-gallon (i.e. approximately <NUM> I) drum 16b (<FIG>), or <NUM>-gallon (i.e. approximately <NUM> I) drum 16c (<FIG>). The design of the containment cask <NUM> is simple and low cost. The first embodiment of the containment cask <NUM> is designed with more shielding than the second embodiment, which will be described in detail later in this document, in order to handle drums having higher radioactive waste content.

The CCV <NUM> has an elongated cylindrical body <NUM> extending between a top end and a bottom end. The CCV body includes a cylindrical side wall <NUM>, a planar bottom plate <NUM> at the bottom end and welded to the side wall <NUM>, a flared bolt flange <NUM> with an open top welded to the side wall <NUM> at the top end, and a circular planar lid <NUM> mounted to the top of the flared bolt flange <NUM> and over the open top. The side wall <NUM>, the bottom plate <NUM>, the flared bolt flange <NUM>, and the lid <NUM>, together in combination, define an interior region that contains the single drum <NUM> and provides leak-tight containment of the radioactive materials within the CCV <NUM>. The CCV <NUM> is made from stainless steel and is the primary shielding mechanism for the contained drum <NUM>. When in use for transport and storage, the CCV <NUM> is in a completely sealed configuration.

<FIG> is an exploded view of the OSV <NUM>. The OSV <NUM> has an elongated cylindrical OSV body <NUM> extending between a top end and a bottom end. The OSV body <NUM> includes a side wall <NUM>, a planar bottom plate <NUM> at the bottom end that is integral to the side wall <NUM>, and a circular planar lid <NUM> mounted to the side wall <NUM> at the top end and over the open top of the OSV <NUM>. The OSV body <NUM> defines an interior region that contains the CCV <NUM> having the single drum <NUM> containing the radioactive hazardous waste. The OSV <NUM> is not a pressure maintaining assembly, but merely a structure to protect the CCD <NUM> from external events, such as potential drops, punctures, fire, etc..

The OSV <NUM> comprises supplemental shielding required to reduce the external radiation dose rates to acceptable levels. In the preferred embodiment, the side wall <NUM>, bottom plate <NUM>, and lid <NUM> of the OSV <NUM> is made from ductile cast iron. In the preferred embodiment, the thickness of the iron side wall <NUM> is (a) about <NUM> (<NUM> inches) between the impact limiters <NUM>, (b) about <NUM> (<NUM> inches) where the impact limiters <NUM> overhang the ends of the OSV, and (c) about <NUM> (<NUM> inches) at the bottom end. The containment cask <NUM> can be used to transport and store a drum <NUM> having RH-TRU waste and/or irradiated fuel waste. Moreover, RH-TRU and irradiated fuel waste can exhibit a decay heat of no greater than <NUM> Watts and <NUM> Watts, respectively.

The lid <NUM> at the top end is bolted to the OSV body <NUM> via a plurality of alloy steel bolts <NUM> with steel washers <NUM> and an elastomeric gasket weather seal to prevent water intrusion. Alignment pins are also used to facilitate OSV lid alignment and installation operations.

The OSV <NUM> includes one or more drain ports <NUM>, preferably one, with corresponding drain port plugs <NUM> for enabling and disabling drainage. The drain port <NUM> is provided to allow the OSV cavity to be checked for the presence of liquids, and drained if needed, during storage or site operations. The drain port may also be used for continuous monitoring, if required by the site and/or the governing regulations. The drain port <NUM> can enable free draining, when the containment cask <NUM> is in storage mode, to prevent trapping of water in the interior region of the OSV <NUM> that is outside of the sealed CCV <NUM>.

A plurality of diametrically opposed lifting trunnions <NUM> are positioned on opposing sides and extend outwardly from the surface of the OSV body <NUM> to enable vertical handling of the containment cask <NUM> and securing of the containment cask <NUM>. The lifting trunnions <NUM> are cast into the OSV body, are a simple lift yoke design that can be operated without special equipment, and comply with ANSI-N14. <NUM> industry standards. The lifting trunnions <NUM> can also be used to tie down the containment cask <NUM> for transport.

A plurality of tie-down lugs <NUM> are also positioned to extend outwardly from the surface of the OSV body <NUM> to enable the containment cask <NUM> to be secured. As an example, the tiedown lugs <NUM> enable the containment cask <NUM> to be secured to a trailer bed. Because of the light weight of the containment cask <NUM> (i.e., CCV weight of between approximately <NUM> (<NUM> lb. ) and approximately <NUM> (<NUM> lb. ) and gross cask weight of between approximately <NUM> (<NUM>,<NUM> lb. ) and approximately <NUM> (<NUM>,<NUM> lb. )), up to three of the containment casks <NUM> can be shipped per road shipment, and the tie down arms <NUM> can be used to secure them to a trailer bed.

The OSV <NUM> includes a plurality of upper impact limiter attachment lugs <NUM> extending outwardly from the OSV body <NUM> so that an upper impact limiter <NUM> can be situated at the top end of the OSV <NUM>. The OSV <NUM> further includes a plurality of lower impact limiter attachment lugs <NUM> extending outwardly from the OSV body <NUM> so that a lower impact limiter <NUM> can be situated at the bottom end of the OSV <NUM>. In the preferred embodiment, each of the upper and lower impact limiters <NUM> are identical in construction.

The impact upper and lower impact limiters <NUM> are symmetric and interchangeable. As shown in <FIG>, each impact limiter <NUM> has a pocket on the inside that fits over the respective end of the OSV <NUM>. Each impact limiter <NUM> has a stainless steel shell <NUM> encapsulating a rigid polyurethane foam <NUM>. In the preferred embodiment, the shell has a thickness of about <NUM> inches. Each impact limiter <NUM> includes a plurality of attachment lugs <NUM> that engage and attach to attachment lugs <NUM> (<FIG>) associated with the OSV <NUM> using preferably T-bolt type connections. A drain tube <NUM> enables water to exit the annular gap region between the bottom impact limiter <NUM> and the OSV <NUM>. For the top impact limiter <NUM>, the drain tube <NUM> is capped to prevent water intrusion. A bottom rub ring <NUM> and a plurality of radial rub strips <NUM> are designed to engage the outside of the OSV <NUM>. A shear ring <NUM> provides a shearing effect, if needed. Other suitable types of impact limiters are known and could be utilized instead of the one associated with the preferred embodiment.

In the preferred embodiment, the containment cask <NUM> measures about <NUM> inches in diameter and about <NUM> inches in vertical height. Moreover, the robust design enables storage of the containment cask <NUM> in an existing building or outdoors.

A second embodiment of the containment cask, denoted by reference numeral <NUM>', will now be described with reference to <FIG>. The containment cask <NUM>' (second embodiment) is designed to be smaller and lighter in terms of weight than the containment cask <NUM> (first embodiment) in order to maximize the number of containment casks that can be transported in a single consignment. <FIG> is a perspective view of the containment cask <NUM>'. <FIG> is a perspective view of the second embodiment with cutaway showing an unshielded overpack assembly <NUM> (outer container) that contains the CCV <NUM> (<FIG>) that is designed to contain a single drum <NUM> (<FIG>) having radioactive hazardous waste, for example, contact handled transuranic (CHTRU) waste that exhibits a decay heat no greater than <NUM> Watts. <FIG> is a cross sectional view of the containment cask <NUM>'. The overpack assembly <NUM> generally provides minimal supplemental shielding to assist with the primary shielding provided by the CCV <NUM>.

The overpack assembly <NUM> has a cylindrical base assembly <NUM> that is covered by a cylindrical lid assembly <NUM>. The lid assembly <NUM> is bolted to the base assembly <NUM> via a plurality of equally spaced bolts <NUM> to secure the CCV <NUM> within its internal cavity. The base assembly <NUM> and lid assembly <NUM> are generally made of stainless steel shells that are filled with rigid polyurethane foam. There is flexibility in connection with the shielding. Shielding inserts can be optimized for different contents, eliminating the need to repackage some drums that have non-compliant TRU waste and thereby resulting in fewer shipments.

The lid assembly <NUM> has a plurality of lifting tabs <NUM> to enable vertical handling of the lid assembly <NUM> and loaded package <NUM>' using standard rigging. The base assembly <NUM> is equipped with a plurality of tie down arms <NUM> to enable the overpack assembly <NUM> (and containment cask <NUM>') to be secured to a support structure <NUM>. Because of the light weight of the packaging <NUM>' and contents (i.e., CCV weight of about <NUM> (<NUM> lb. ) and gross cask weight between about <NUM> (<NUM>,<NUM> lb. ) to <NUM> (<NUM>,<NUM> lb. )), up to ten of the containment casks <NUM>' can be shipped per road shipment, and the tie down arms <NUM> can be used to secure them to a trailer bed.

As shown in <FIG>, the overpack assembly <NUM>, when assembled, has an elongated cylindrical body extending between a top end and a bottom end. There is a planar bottom plate <NUM> at the bottom end that is welded to the body of the base assembly <NUM>, and there is a planar top plate <NUM> at the top end that is welded to the body of the lid assembly <NUM>.

As for foam inserts, the sides of the base assembly <NUM> has outer and inner stainless steel shells 75a, 75b with side foam <NUM> between them. The sides of the lid assembly <NUM> also has outer and inner stainless steel shells 78a, 78b with side foam <NUM> between them. The bottom end of the base assembly <NUM> includes corner foam <NUM> and center foam <NUM>. A thermal spider may also be situated in the center foam <NUM> for heat dissipation. The top end of the lid assembly <NUM> includes corner foam <NUM> and center foam <NUM>. The thickness of the outer and inner shells are designed for optimal crushing properties, and in the preferred embodiment, are <NUM>/<NUM> inches and <NUM> gauge, respectively.

In terms of dimensions, in the preferred embodiment, the containment cask <NUM>' measures about <NUM>,<NUM> (<NUM> inches) in diameter and about <NUM>,<NUM> (<NUM> inches) in vertical height.

<FIG> is a perspective view and <FIG> is an exploded view of the CCV <NUM> (of <FIG> and <FIG>) that is stored within the first and second embodiments of the containment cask <NUM>, <NUM>'. As shown in <FIG> and <FIG>, the CCV <NUM> has an elongated cylindrical body <NUM> extending between a top end and a bottom end. The CCV body includes a cylindrical side wall <NUM>, a planar bottom plate <NUM> at the bottom end and welded to the side wall <NUM>, a flared bolt flange <NUM> with an open top welded to the side wall <NUM> at the top end, and a circular planar lid <NUM> mounted to the top of the flared bolt flange <NUM> and over the open top. The side wall <NUM>, the bottom plate <NUM>, the flared bolt flange, and the lid <NUM>, together in combination, define an interior region that contains the single drum <NUM> and provides sufficient shielding to contain radiation within the CCV <NUM>. In the preferred embodiment, the drum <NUM> can have a fissile gram equivalent (FGE; i.e., grams of plutonium <NUM>) up to <NUM>.

The lid <NUM> is mounted to the flared bolt flange <NUM> via a plurality of captured closure bolts <NUM> with corresponding washers <NUM>. The captured bolts <NUM> facilitate remote lid installation and removal operations that are required for certain payloads. Alignment pins are used to facilitate CCV lid alignment and installation operations. A plurality of spaced-apart, concentric O-rings <NUM> (elastomeric gasket weather seal; inner for containment; outer for test) are situated between the lid <NUM> and the bolt flange <NUM> of the CCV <NUM>. A plurality of threaded holes <NUM> in the lid <NUM> enable the CCV <NUM> to be vertically lifted and lowered using standard rigging (wires ropes, shackles, swivel hoist rings). In the preferred embodiment, the CCV <NUM> has a diameter of about <NUM>,<NUM> (<NUM> inches) and a vertical height of about <NUM>,<NUM> (<NUM> inches).

The CCV <NUM> includes a test port assembly <NUM> that can be used to test the sealing capability (vent and leak) of the CCV <NUM> using known techniques. In essence, the test port assembly <NUM> is used to evacuate the CCV <NUM>, backfill the CCV <NUM> with an inert gas, such as Helium, and then check for leaks. The test port assembly <NUM> has a port cover <NUM> that is mounted within a circular lid aperture <NUM> via a plurality of port cover bolts <NUM>. Dual O-rings <NUM> (inner for containment; outer for test) are used between the port cover <NUM> and a donut shaped bottom associated with the circular lid aperture <NUM>. A quick connect valve <NUM> is mounted over a circular lid hole <NUM> to enable access to the inner atmosphere of the CCV <NUM>. The quick connect valve <NUM> is accessed by removing the port cover <NUM>.

One or more modular supplemental shields may be added to the CCV <NUM>, or a separate shield liner (e.g., the payload liner described later) may be added to the interior cavity of the CCV <NUM>. These additional shields may be added as liners to the CCV <NUM>. Each shield can be optimized for a specific set or type of radioactive hazardous waste.

Depending on the size and shielding requirements of the various payloads, a payload liner may be used inside the CCV cavity to shore the contents within the CCV cavity and provide additional shielding. A payload liner may be made from various materials and sizes, depending on the type and amount of shielding that is required.

<FIG> are cross sectional views of the CCV <NUM> containing different size drums 16a, 16b, and 16c, respectively, having radioactive hazardous waste by using different size payload liners 118a, 118b, and 118c, respectively. Specifically, <FIG> shows a U. standard <NUM>-gallon (approximately <NUM>) drum 16a. <FIG> shows a U. standard <NUM>-gallon (approximately <NUM> I) drum 16b. <FIG> shows a U. standard <NUM>-gallon (approximately <NUM> I) drum 16c.

With reference to <FIG>, the payload liner 118a has a circular platform 122a upon which the drum 16a rests. A cylindrical lower part 124a with a cylindrical internal region supports the platform 122a over the bottom plate <NUM> of the CCV <NUM>.

Referring to <FIG>, the payload liner 118b has an elongated body having a top part 126b with a cylindrical internal region, a lower part 124b with a cylindrical internal region, and a circular planar platform 122b between and separating the top and lower parts 126b, 124b. The cylindrical lower part 124b supports the platform 122b over the bottom plate <NUM> of the CCV <NUM>. The drum 16b is contained in the internal region of the top part 124b between the top of the CCV <NUM> and the platform 122b of the liner 118b. The top part 126b is also designed to generally center the single drum 16b within the CCV <NUM> along a vertical axis extending between the top end and the bottom end of the CCV <NUM>.

Referring to <FIG>, the payload liner 118c has an elongated body having a top part 126c with a cylindrical internal region, a lower part 124c with a cylindrical internal region, and a circular planar platform 122c between and separating the top and lower parts 126c, 124c. The cylindrical lower part 124c supports the platform 122c over the bottom part <NUM> of the CCV <NUM>. The drum 16c is contained in the internal region of the top part 124c between the top of the CCV <NUM> and the platform 122c of the liner 118c. The top part 126c is also designed to generally center the single drum 16c within the CCV <NUM> along a vertical axis extending between the top end and the bottom end of the CCV <NUM>.

The payload liner <NUM> may be made from a variety of different materials. In some embodiments, the payload liner <NUM> may comprise supplemental shielding to assist with containing the radioactive hazardous waste within the drum <NUM>. In one embodiment, among others, the payload liner <NUM> is made of stainless steel, which is itself, a shielding material. In another embodiment, among others, the payload liner <NUM> is made from a polyurethane foam, which is not shielding but absorbs neutrons.

It should be emphasized that the above-described embodiments of the present invention, particularly, any "preferred" embodiments, are merely possible nonlimiting examples of implementations, merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention as set out in the claims. All such modifications and variations are intended to be included herein within the scope of this disclosure.

As an example, the containment casks <NUM> and <NUM>' can accommodate drum sizes that are different than those described.

Claim 1:
A containment cask (<NUM>, <NUM>') for safely transporting and storing radioactive hazardous waste, the cask (<NUM>, <NUM>') comprising:
a single drum (<NUM>) containing the radioactive hazardous waste;
a containment vessel (<NUM>) having an elongated cylindrical body (<NUM>) extending between a top end and a bottom end, the body (<NUM>) having an elongated cylindrical side wall (<NUM>), a circular planar bottom plate (<NUM>) mounted to the side wall (<NUM>) at the bottom end, and a circular planar lid (<NUM>) mounted to the side wall (<NUM>) at the top end, wherein the body (<NUM>) defines an interior region that contains the single drum (<NUM>) and provides shielding to inhibit radiation emitted from the single drum (<NUM>);
an outer container (<NUM>) having an elongated cylindrical body (<NUM>) extending between a top end and a bottom end, the body (<NUM>) having an elongated cylindrical side wall (<NUM>), a circular planar bottom plate (<NUM>) mounted to the side wall (<NUM>) at the bottom end, and a circular planar lid (<NUM>) mounted to the side wall (<NUM>) at the top end, wherein the body (<NUM>) defines an interior region that contains the containment vessel (<NUM>) having the single drum (<NUM>) containing the radioactive hazardous waste; characterized by
a payload liner (<NUM>, 118a, 118b, 118c) within the containment vessel (<NUM>), the liner (<NUM>, 118a, 118b, 118c) having an elongated body having a top part (126a, 126b, 126c) with a cylindrical internal region, a lower part (124a, 124b, 124c) with a cylindrical internal region, and a planar platform (122a, 122b, 122c) between and separating the top and lower parts (126a, 126b, 126c; 124a, 124b, 124c).