Tank for disposing hazardous radioactive waste in underground borehole repository

Abstract

Various embodiments of a tank for handling hazardous radioactive waste in a borehole repository are disclosed. The can has a housing body that accommodates waste. In one embodiment, the tank is equipped with a removable hoist adapter that enables the tank to be placed into and removed from the drilling repository. A cover assembly at the top end of the housing body includes a shielding closure plug, a keyhole joint to and from which a removable hoist adapter is attached, a cover ring, and a threaded locknut that secures and releases the cover ring and hoist adapter to and from the keyhole joint.

Description

Declaration of priority for containers used to dispose of hazardous radioactive waste in underground borehole disposal facilities

[0001] This application claims priority and benefit to co-pending U.S. Utility Application No. 18 / 526,762, filed December 1, 2023, entitled “Canister for Disposal of Hazardous Radioactive Waste in an Earth Borehole Repository,” and also claims priority and benefit to Provisional Application No. 63 / 531,450, filed August 8, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The embodiments of this disclosure generally relate to the disposal of hazardous radioactive materials, and more specifically, to a container for disposing of hazardous radioactive waste (e.g., spent nuclear fuel and / or highly radioactive waste) in an underground borehole disposal facility. Background Technology

[0003] The container assembly for containing hazardous radioactive waste is a core component common to the storage, transport, and permanent disposal of such waste. The container holds the waste in an inert gas environment to prevent fuel cladding degradation and provides primary containment for used fuel assemblies and associated radioactive materials and fissile gases. Typically, waste is wet-loaded into the container from the spent fuel pool at the reactor site (or repackaging facility), and the container is drained, vacuum-dried, refilled with inert gas, and sealed with welded metal before being placed into dry storage and / or transported to a temporary storage facility or repository. Alternatively, although less common, used fuel may also be loaded into the container in a dry environment (e.g., a hot chamber). The container is suitable for disposal in deep borehole repositories or excavated geological repositories.

[0004] U.S. Patent No. 10,692,618 and PCT Patent Application Serial No. PCT / US2023 / 034389, filed October 3, 2023 (which is incorporated herein by reference), describe hazardous waste containers and systems for disposing of containers containing hazardous radioactive materials in underground disposal facilities. These containers have baskets for containing the hazardous radioactive materials. The containers are placed in a borehole defined by a plurality of cylindrical steel sleeves bolted together or otherwise secured. The borehole is filled with a fluid (e.g., a brine solution) and can reach depths of up to 5 kilometers underground, thereby exerting extreme pressure on the containers. Furthermore, the borehole may simultaneously have vertical and non-vertical (e.g., horizontal or transverse to vertical) sections.

[0005] Despite the significant advantages of the aforementioned tanks and systems, these technologies are still in their early stages, and many obstacles remain to their practical implementation. This disclosure focuses on a tank design that enables the easy and safe placement and removal of the tank from a borehole disposal facility. Summary of the Invention

[0006] This article discloses various embodiments of containers for disposing of hazardous radioactive waste in borehole disposal facilities.

[0007] In one embodiment, the can includes a shell body for containing waste. The can is equipped with a removable lifting adapter that allows the can to be placed into and removed from a borehole disposal chamber. A cap assembly located at the top of the shell body includes a sealing plug, a locking connector, a cap ring, and a threaded lock nut. The removable lifting adapter is attached to and removed from the locking connector, and the threaded lock nut secures the cap ring and lifting adapter to and releases them from the locking connector.

[0008] In another embodiment, the container includes a shell located within a borehole disposal repository. The shell has an elongated cylindrical shell body extending between a top and a bottom end, defining an elongated cylindrical cavity for containing radioactive waste. A cover assembly is located at the top end of the shell body. The cover assembly has a generally cylindrical closure plug having an elongated cylindrical body extending between the top and bottom ends. The closure plug extends within the cavity of the shell body to the top end of the shell body.

[0009] It is worth noting that, in this embodiment, the elongated body of the closure plug has a top portion with a first circular cross-section and a bottom portion with a second circular cross-section. The first circular cross-section is larger than the second circular cross-section, thus creating a support frame between the top and bottom portions. Furthermore, the top and bottom portions of the shell body have different circular cross-sections that substantially correspond to the first and second circular cross-sections of the cap assembly, such that the plug of the cap assembly is positioned within the shell in a mating engagement manner, and the top portion of the plug exerts a downward vertical force on the bottom portion of the shell body at the support frame.

[0010] In another embodiment, the container has a shell comprising an elongated cylindrical body extending between a top and a bottom. The container defines an elongated cylindrical cavity for containing radioactive waste. A closure plug having the elongated cylindrical body with a top and a bottom extends within the cavity of the shell body to the top of the shell body. A closure cap is located at the top of the shell body. An annular clearance groove is defined by a portion of the plug and a portion of the shell body. Notably, this annular clearance groove enables the closure cap and the shell body to be secured together using K-TIG welding and provides a primary containment boundary for the radioactive contents of the container.

[0011] In another embodiment, the can includes a shell having an elongated cylindrical body extending between a top and a bottom. The can defines an elongated cylindrical cavity for containing radioactive waste. A lid assembly is attached to and located on top of the shell body. The lid assembly has a circular outer edge with a top surface and a bottom surface. The top and bottom surfaces have their respective top and bottom edges. Notably, the top edge is rounded to prevent the can from snagging when it is pulled out of the borehole disposal silo.

[0012] Other embodiments, apparatuses, systems, methods, features, and advantages of the present invention will become apparent to those skilled in the art upon review of the following drawings and detailed descriptions. All such additional embodiments, apparatuses, systems, methods, features, and advantages are intended to be included within this disclosure, fall within the scope of protection of the present invention, and are protected by the appended claims. Attached Figure Description

[0013] Many aspects of this disclosure can be better understood by referring to the following accompanying drawings. The components in the drawings are not necessarily drawn to scale; the emphasis is on clearly illustrating the principles of this disclosure. Furthermore, in the drawings, the same reference numerals denote corresponding parts in the various views.

[0014] Figure 1 is a schematic diagram of a tank located in a borehole treatment reservoir according to the present disclosure.

[0015] Figure 2A is an enlarged side view of the can of Figure 1, showing the components of the lid assembly for the can of Figure 1.

[0016] Figure 2B is a cross-sectional view of the tank in Figure 1.

[0017] Figure 3A is a cross-sectional view of the tank of Figure 1 taken along line AA of Figure 3B, showing an enlarged view of (a) the support frame that enhances the strength of the cap assembly and (b) the clearance groove that enables K-TIG welding.

[0018] Figure 3B is a top view of the tank in Figure 1, with a lock hole connector and a cap ring, but without the lifting adapter and lock nut.

[0019] Figure 3C is a cross-sectional view of the longitudinal shell body of the tank in Figure 1, taken along line BB in Figure 2A. Detailed Implementation

[0020] Figure 1 is a schematic diagram illustrating a tank 10 in a borehole disposal reservoir 12 located in underground soil 14 according to an embodiment of the present disclosure. The borehole disposal reservoir 12 has an elongated cylindrical cavity for receiving one or more tanks 10. The borehole associated with the borehole disposal reservoir 12 may have both vertical and non-vertical (e.g., horizontal or transverse to vertical) portions, but for simplicity, only the vertical portion is shown in Figure 1.

[0021] The tank's dimensions in length and diameter are variable to accommodate different fuel types, but they share common features for ease of operation. Tank 10 is designed to withstand a range of load conditions required for storage, transport, and disposal, but the tank's shell thickness typically depends on the hydrostatic pressure load at the depth during borehole disposal.

[0022] In a preferred embodiment, as shown in FIG2A, tank 10 includes a shell assembly 16 having a shell body 18 and a field-installed cover assembly 22, which together form a tank cavity 24 in which hazardous radioactive waste 26 is placed. Hazardous radioactive waste 26 may be, for example, but not limited to, chemical, biological, and / or nuclear materials. In a preferred embodiment, tank 10 stores spent nuclear fuel in the form of spent nuclear fuel rod assemblies. Hazardous radioactive waste 26, particularly nuclear waste, may be in solid, liquid, and / or gaseous form. The shell body 18 is preferably a welded steel component, and the components of the shell assembly 16 are made of materials highly resistant to localized corrosion (e.g., chloride-induced stress corrosion cracking, or CISCC) and general corrosion. Tank 10 also includes drainage and venting features (as shown in FIG3A) for drainage, vacuum drying, and refilling of the tank cavity with fluids or solids, such as inert gases (e.g., helium), during wet loading operations.

[0023] The cover assembly 22 has a lifting adapter 28, which is detachably attached to a locking port connector 32 at the top of the tank 10 and secured by a cover ring 34 and a locking nut 36 to provide a lifting interface for operations at the borehole disposal facility ground site and for operations to place or retrieve the tank from the borehole disposal facility 12. The lifting adapter 28 is optional for storage and transport operations, but is installed for borehole disposal operations as it is used to place or retrieve the tank from the borehole disposal facility 12.

[0024] More specifically, referring to Figure 2B, the field-installed cover assembly 22 includes a generally cylindrical shielding plug 38 having an elongated cylindrical body with a top and a bottom. The shielding plug 38 extends within the cavity of the shell body 18 to the top of the shell body 18. The plug 38 of the cover assembly 22 is preferably a thick cylindrical steel plug, which is relied upon for primary radiation shielding during certain tank loading activities.

[0025] As shown in Figure 3A, an annular closure ring 39 secures the closure plug 38 within the housing body 18. The closure ring 39 has a circular outer edge with a top surface and a bottom surface and a centrally located circular orifice. The closure ring 39 is preferably made of steel and is attached to the top of the housing body 18 by a TIG welding process, thus securing the closure plug 38 within the housing body 18.

[0026] The keyhole connector 32 shown in Figure 3B has a circular outer edge and a top surface and a bottom surface. The bottom surface is located above the top of the shielding closure plug 38. The keyhole connector 32 has a keyhole 42 extending through the keyhole connector 32 between the top and bottom surfaces. The keyhole can be accessed through the orifice of the closure ring. The keyhole connector 32 is preferably made of steel. The one-piece keyhole connector 32 facilitates handling operations. The innovative keyhole connector 32 provides a mechanism for easy, fault-protected remote engagement of the tank 10 using specialized tools for pool loading and tank transfer operations to minimize worker radiation exposure.

[0027] As shown in Figures 2A and 2B, the lifting adapter 28 has an elongated body with a top and a bottom. The bottom end of the lifting adapter 28 is detachably attached to the keyhole connector 32. The top end of the lifting adapter 28 allows the canister 10 to be placed into and removed from the drilled disposal chamber 12. The lifting adapter 28 is preferably made of steel. The lifting adapter 28 has a pair of radially opposing, outwardly extending lugs 44, which are sized and shaped to pass through the keyhole 42 when the lifting adapter 28 is in a first rotational position. The lifting adapter 28 can then be moved to a second rotational position, which is transverse (preferably perpendicular) to the first rotational position, and allows the lifting adapter 28 to be gripped and secured to the bottom surface of the keyhole connector 32.

[0028] The top of the lifting adapter 28 includes internal and external contours for docking with standard oil and gas equipment used in drilling operations (i.e., GS tools and flow-release retrieval containers), providing redundant lifting means. The internal contour 28a in Figure 2B is a stepped cylindrical notch for docking with a standard GS tool to lift the container. The external contour 28b in Figure 2B has a smooth cylindrical shape for docking with a standard flow-release retrieval container tool to lift the container 10.

[0029] The cover ring 34 has a circular outer edge with a top surface, a bottom surface, and a centrally located circular orifice 46. During installation, a lifting adapter 28 extends through the orifice 46. The bottom surface of the cover ring 34 has a pair of downwardly extending lugs 32a (as shown in FIG. 2A) at opposite ends, which extend into the end portions 35a, 35b of the locking hole 42 (as shown in FIG. 3B) to prevent the lifting adapter 28 from rotating about its longitudinal axis from a second rotational position (fixed state) to a first rotational position (unfixed state). The cover ring 34 is preferably made of steel. Typically, the cover ring 34 is concentrically positioned above the locking hole connector 32, which in turn is concentrically positioned above the closing ring 39. Notably, the circular outer edge of the top surface of the cover ring 34 has rounded or chamfered edges 41 to prevent snagging when removing the can 10 from the drilled disposal chamber 12.

[0030] The locking nut 36 in Figures 2A and 2B secures the cover ring 34 and the lifting adapter 28 to the lock hole connector 32. The locking nut 36 is preferably made of steel and has a female machine thread that engages with the male machine thread associated with the lifting adapter 28.

[0031] As shown in Figure 3C, the internal components of the container for hazardous radioactive waste 26 include a stainless steel fuel tube 52 and four stainless steel corrugated side supports 54a-54d, which are welded to the outer surface of the fuel tube 52 to bridge the gap between the fuel tube 52 and the shell body 18. The side supports 54a-54d also transfer heat from the waste to the shell body 18.

[0032] The shielding shell body 18 and shielding closure plug 38 of the can 10 include a significant stepped cylindrical feature, which enhances the strength of the cover assembly 22. Due to the borehole being filled with fluid (such as a brine solution) and extending up to 5 kilometers underground, the can 10 will be subjected to enormous pressure-induced forces. More specifically, as shown in Figure 3A, the elongated body of the shielding closure plug 38 has a top portion 38a with a first circular cross-section and a bottom portion 38b with a second circular cross-section. The diameter of the first circular cross-section is larger than that of the second circular cross-section, thus creating a support shelf 56 between the top portion 38a and the bottom portion 38b. Furthermore, the shell body 18 has a top portion 18a and a bottom portion 18b with circular cross-sections of different diameters that substantially correspond to the diameters of the first and second circular cross-sections of the cover assembly 22, such that the closure plug 38 of the cover assembly 22 is located within the shell 18 in a mating engagement manner, and the top portion 38a of the closure plug 38 exerts a downward vertical force on the bottom portion 18b of the shell body 18 at the support shelf 56.

[0033] The stepped cylindrical feature eliminates the need for temporary cover supports that encroach on the volume of the tank cavity. The stepped cylindrical feature also supports extreme external loads from hydrostatic pressure during drilling operations, thereby protecting the closed weld 62 (Fig. 3A) from excessive shear loads that could lead to structural failure.

[0034] An enlarged view of Figure 3A shows a drain port 61 with a quick-connect fitting, used only to provide context. This port is used to draw water from tank 10. Drain port 61 is covered and sealed by an annular cap 63, which is welded as shown, preferably using a TIG welding process.

[0035] Can 10 also includes an innovative feature that allows for the use of advanced welding techniques to perform a field-sealed weld 62 from the cap to the shell. Specifically, as shown in FIG3A, an open annular clearance groove 58 enables the use of K-TIG welds (the other welds shown in the figure use TIG welds). Preferably, the clearance groove 58 is an open groove 58 with a generally rectangular cross-section that extends in a circular manner around the top of the plug 38 and the shell 18 below the location of the sealing weld 62 (which attaches the sealing ring 39 to the shell body 18). Typically, about half of the clearance groove 58 is located in the top portion of the plug 38, while the other half is located in the top portion of the shell body 18.

[0036] K-TIG welding uses a self-fusion keyhole welding process (which eliminates the need for filler metal) to complete most of the sealing weld thickness, and adds weld metal to the keyhole bead using conventional tungsten inert gas TIG welding (melt-in mode) to achieve the desired total weld throat. Compared to other conventional welding techniques, such as multi-layer TIG welding previously used for tank field sealing welds, it significantly reduces welding time and produces less weld deformation. K-TIG welding is a highly efficient welding technique for seam welding on tanks, containers, and hulls with square butt joints and bevel joints, but it has not been previously used for field sealing welds on spent fuel tanks due to limitations in weld joint configuration. The innovative clearance groove 58 allows the high energy of the arc to escape through the back of the weld, thus avoiding turbulence at the root that leads to porosity in the weld. The clearance groove 58 also allows for weld inspection using ultrasonic testing (UT) methods, providing a higher level of weld quality assurance than other methods used for tank sealing welds.

[0037] Finally, it should be emphasized that the above-described embodiments of the present invention, especially any "preferred" embodiments, are merely possible, non-limiting examples, and are only illustrated for a clear understanding of the principles of the invention. Many changes and modifications can be made to the above-described embodiments of the present invention without substantially departing from the spirit and principles of the invention. All such modifications and changes are intended to be included within the scope of this disclosure.

Claims

1. A system for disposing of hazardous radioactive waste, the system comprising: A borehole treatment chamber having an elongated cylindrical cavity extending into the ground; A container located in the borehole disposal facility, the container having an elongated cylindrical shell body extending between a top and a bottom, the container defining an elongated cylindrical cavity for containing the radioactive waste; The device includes a lifting adapter having an elongated body with a top and a bottom end, the bottom end of which is attached to the top of the can, the top of which is capable of placing and removing the can into and from the borehole; a cap assembly located at the top of the shell body, the cap assembly including: a generally cylindrical closure plug having an elongated cylindrical body with a top and a bottom end, the closure plug extending within a cavity of the shell body to the top of the shell body; a locking connector having a circular outer edge and a top surface and a bottom surface, the bottom surface being located above the top of the closure plug, the locking connector having a locking hole extending through the locking connector between the top and bottom surfaces; and a lifting adapter having an elongated body with a top and a bottom end, the bottom end of which is attached to the locking connector, the top of which is capable of placing and removing the can into and from the borehole. The lifting adapter has an outwardly extending lug, the size and shape of which allow it to pass through the lock hole when the lifting adapter is in a first rotational position and to grip the bottom surface of the lock hole connector when the lifting adapter is in a second rotational position, the first and second rotational positions being lateral, and wherein the lifting adapter is in the second rotational position; a cover ring having a circular outer edge with a top surface, a bottom surface, and a centrally located circular orifice, through which the lifting adapter extends, the bottom surface having a downwardly extending lug that extends into and through the lock hole to prevent the lifting adapter from rotating about its longitudinal axis from the second rotational position to the first rotational position; and a locking nut securing the cover ring and the lifting adapter to the lock hole connector, the locking nut having threads that engage with the threads associated with the lifting adapter.

2. The system according to claim 1 further includes a stepped cylindrical feature, wherein: The slender body of the closure plug has a top portion with a first circular cross-section and a bottom portion with a second circular cross-section, the first circular cross-section being larger than the second circular cross-section, such that a support frame exists between the top portion and the bottom portion; The shell body has a top portion and a bottom portion, the top portion and the bottom portion having different circular cross-sections that substantially correspond to the first and second circular cross-sections of the cover assembly, such that the plug of the cover assembly is located within the shell in a mating engagement manner, and the top portion of the plug exerts a downward vertical force on the bottom portion of the shell body at the support frame.

3. The system according to claim 1, wherein, The cover assembly further includes: an annular closure ring having a circular outer edge with a top surface, a bottom surface, and a centrally located circular orifice, the closure ring being attached to the top of the shell body and securing the plug within the shell body, and the lock hole being accessible through the orifice of the closure ring; an annular clearance groove defined in the top portion of the plug; and a K-TIG weld located above the annular clearance groove, the K-TIG weld securing the closure plug to the shell body.

4. The system according to claim 3, wherein, The annular clearance groove has a square rectangular cross-section, and approximately half of the clearance groove is located in the top portion of the plug, while the other half is located in the top portion of the shell body.

5. The system according to claim 1, wherein, The outer circular edge of the top surface of the cap ring has rounded corners to prevent the can from getting caught when it is removed from the borehole treatment chamber.

6. The system of claim 1, further comprising a fuel tube having an elongated body with four sides extending between a top and a bottom end, the fuel tube having a generally square cross-section, the fuel tube containing the radioactive waste, and the system further comprising four elongated corrugated side supports, each of the side supports being designed to bridge the gap between the shell body and a corresponding side of the fuel tube.

7. A container for disposing of hazardous radioactive waste in a borehole disposal facility, the container comprising: A housing having an elongated cylindrical body extending between a top and a bottom end, the container defining an elongated cylindrical cavity for containing the radioactive waste; A cap assembly located at the top of the shell body, the cap assembly and the shell body together defining a cavity, the cap assembly comprising: a generally cylindrical closure plug having an elongated cylindrical body with a top end and a bottom end, the closure plug extending within the cavity of the shell body to the top end of the shell body; a keyhole connector having a circular outer edge and a top surface and a bottom surface, the bottom surface being located above the top end of the closure plug, the keyhole connector having a keyhole extending through the keyhole connector between the top surface and the bottom surface; a lifting adapter having an elongated body with a top end and a bottom end, the bottom end of the lifting adapter being attached to the keyhole connector, the top end of the lifting adapter being capable of placing the can into and removing it from the drill hole, the lifting adapter having an outwardly extending lug, the lug being of a certain size and shape. The lifting adapter is positioned such that it can pass through the lock hole in a first rotational position and grip the bottom surface of the lock hole connector in a second rotational position, wherein the first and second rotational positions are lateral, and wherein the lifting adapter is in the second rotational position; a cover ring having a circular outer edge with a top surface, a bottom surface, and a centrally located circular orifice, the lifting adapter extending through the orifice, the bottom surface having a downwardly extending lug extending into and through the lock hole to prevent the lifting adapter from rotating about its longitudinal axis from the second rotational position to the first rotational position; and a locking nut securing the cover ring and the lifting adapter to the lock hole connector, the locking nut having threads that engage with the threads associated with the lifting adapter.

8. The tank according to claim 7, further comprising a stepped cylindrical feature, wherein: The slender body of the closure plug has a top portion with a first circular cross-section and a bottom portion with a second circular cross-section, the first circular cross-section being larger than the second circular cross-section, thereby creating a support frame between the top portion and the bottom portion. The shell body has a top portion and a bottom portion, the top portion and the bottom portion having different circular cross-sections that substantially correspond to the first and second circular cross-sections of the cover assembly, such that the plug of the cover assembly is located within the shell in a mating engagement manner, and the top portion of the plug exerts a downward vertical force on the bottom portion of the shell body at the support frame.

9. The tank according to claim 8, wherein, The cap assembly further includes: an annular closure ring having a circular outer edge with a top surface, a bottom surface, and a centrally located circular orifice; the closure ring being attached to the top of the shell body and welded to the closure plug and the shell to cover the K-TIG closure weld; and access to the locking hole through the orifice of the closure ring; an annular clearance groove defined in the top portion of the plug; and a K-TIG weld located above the annular clearance groove, the K-TIG weld securing the closure plug to the shell body and providing a primary containment boundary for the radioactive waste of the container.

10. The tank according to claim 8, wherein, The annular clearance groove has a square rectangular cross-section, and approximately half of the clearance groove is located in the top portion of the plug, while the other half is located in the top portion of the shell body.

11. The tank according to claim 7, wherein, The outer circular edge of the top surface of the cap ring has rounded corners to prevent the can from getting caught when it is removed from the borehole treatment chamber.

12. The canister of claim 7, further comprising a fuel tube having an elongated body with four sides extending between a top and a bottom end, the fuel tube having a generally square cross-section, the fuel tube containing the radioactive waste, and the canister further comprising four elongated corrugated side supports, each of the side supports being designed to bridge the gap between the shell body and the respective side of the fuel tube.

13. A borehole treatment reservoir, the borehole treatment reservoir comprising the tank according to claim 7.

14. A method for disposing of hazardous radioactive waste, the method comprising the following steps: A can is provided having an elongated cylindrical shell body extending between a top and a bottom end, the shell body defining an elongated cylindrical cavity for receiving the radioactive waste; a keyhole connector is positioned above the top end of the can, the keyhole connector having a circular outer edge and a top surface and a bottom surface, the keyhole connector having a keyhole extending between the top surface and the bottom surface and centrally positioned through the keyhole connector; A lifting adapter is provided, the lifting adapter having an elongated body with a top end and a bottom end, the top end of the lifting adapter being capable of placing the can into and removing it from the drilled hole, the body having an outwardly extending lug, the lug being sized and shaped to penetrate the keyhole when the lifting adapter is in a first rotational position, and to grip the bottom surface of the keyhole connector when the lifting adapter is in a second rotational position, the first and second rotational positions being lateral; the lifting adapter in the first rotational position is inserted into the keyhole; Rotate the lifting adapter to the second rotation position; A cover ring is provided, the cover ring having a circular outer edge with a top surface, a bottom surface and a centrally positioned circular opening, the bottom surface having a downwardly extending lug; the cover ring is fitted onto the lifting adapter through the opening, and then the downwardly extending lug is inserted into and passes through a corresponding portion of the locking hole to prevent the lifting adapter from rotating about its longitudinal axis from a second rotational position to a first rotational position; The cap ring and the lifting adapter are secured to the lock hole joint using a lock nut, the lock nut having threads that engage with the threads associated with the lifting adapter.

15. The method of claim 14, further comprising the step of: The plug is secured in the housing body using an annular closure ring, the closure ring having a circular outer edge with a top surface, a bottom surface and a centrally located circular orifice, through which the locking hole can be accessed; an annular clearance groove is provided defined in the top portion of the plug; And K-TIG welding is performed on the closing ring at the top end near and above the annular clearance groove to fix and seal the plug in the shell body.

16. The method of claim 14, further comprising the step of providing a stepped cylindrical feature, wherein: The slender body of the closure plug has a top portion with a first circular cross-section and a bottom portion with a second circular cross-section, the first circular cross-section being larger than the second circular cross-section, thereby creating a support frame between the top portion and the bottom portion. The shell body has a top portion and a bottom portion, the top portion and the bottom portion having different circular cross-sections that substantially correspond to the first and second circular cross-sections of the cover assembly, such that the plug of the cover assembly is located within the shell in a mating engagement manner, and the top portion of the plug exerts a downward vertical force on the bottom portion of the shell body at the support frame.

17. The method of claim 14, further comprising the step of: A rounded edge is provided at the circular outer edge of the top surface of the cap ring; and the can is prevented from snagging on the borehole casing section when the can is removed from the borehole treatment chamber.

18. The method of claim 14, further comprising a fuel tube located in a cavity of the housing, the fuel tube having an elongated body with four sides extending between a top and a bottom end, the fuel tube having a generally square cross-section, the fuel tube containing the radioactive waste, and the method further comprising four elongated corrugated side supports, each of the side supports being designed to bridge the gap between the housing body and a corresponding side of the fuel tube.

19. The method of claim 14, further comprising the step of: The can is placed into the borehole treatment chamber using the lifting adapter; and the locking nut, cover plate, keyhole connector and lifting adapter are removed from the borehole treatment chamber.

20. A container for disposing of hazardous radioactive waste, the container comprising: A borehole treatment chamber having an elongated cylindrical cavity extending into the ground; A housing located within the borehole disposal container, the housing having an elongated cylindrical shell body extending between a top and a bottom end, the container defining an elongated cylindrical cavity for containing the radioactive waste; a cap assembly located at the top of the shell body, the cap assembly having a generally cylindrical closure plug having an elongated cylindrical body extending between the top and bottom ends, the closure plug extending within the cavity of the shell body to the top of the shell body; wherein the elongated body of the closure plug has a top portion with a first circular cross-section and a bottom portion with a second circular cross-section, the first circular cross-section being larger than the second circular cross-section, thereby creating a support frame between the top and bottom portions; and wherein the shell body has a top portion and a bottom portion having different circular cross-sections that substantially correspond to the first and second circular cross-sections of the cap assembly, such that the plug of the cap assembly is located within the housing in a mating engagement manner, and the top portion of the plug exerts a downward vertical force on the bottom portion of the shell body at the support frame.

21. A container for disposing of hazardous radioactive waste, the container comprising: A housing having an elongated cylindrical body extending between a top and a bottom, the can defining an elongated cylindrical cavity for containing the radioactive waste; and a closure plug having an elongated cylindrical body with a top and a bottom, the closure plug extending within the cavity of the housing body to the top of the housing body. A closed cap located at the top of the shell body; An annular clearance groove defined by a portion of the plug and a portion of the shell body; and a K-TIG weld located above the annular clearance groove, the K-TIG weld securing the plug and the shell body together and providing a primary containment boundary for the radioactive waste of the container.

22. The tank of claim 20, further comprising a borehole treatment reservoir having an elongated cylindrical cavity extending into the ground, wherein the tank is located within the borehole treatment reservoir.

23. A container for disposing of hazardous radioactive waste, the container comprising: A borehole treatment chamber having an elongated cylindrical cavity extending into the ground; The housing located in the borehole disposal facility has an elongated cylindrical shell body extending between a top and a bottom end, and the container defines an elongated cylindrical cavity for containing the radioactive waste; And a cover assembly attached to the top of the shell body and located at the top of the shell body, the cover assembly having a circular outer edge with a top surface and a bottom surface, the top surface and the bottom surface having their respective top edges and bottom edges, the top edges being rounded to prevent the can from snagging when the can is pulled out of the borehole treatment chamber.

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