Integrated ion-exchange disposal and treatment system

Abstract

To provide an integrated ion-exchange disposal and treatment system.SOLUTION: There is disclosed a canister for interim storage and subsequent consolidation of waste materials via hot pressing. In an embodiment, the canister comprises at least one ion exchange material, and is configured to: house the ion exchange material after it is exchanged with contaminating ions without releasing the contaminating ions; and consolidate via hot-isostatic pressing. Also disclosed are a step of contacting a fluid waste with an ion exchange material, where the ion exchange material is located in a canister; evacuating the canister; and applying hot-isostatic pressing (HIP) processing to the canister until it collapses under HIP conditions.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 443,254, filed January 6, 2017, which is incorporated herein by reference in its entirety.

[0002] Technical Field The disclosed embodiments generally relate to canisters for intermediate storage and subsequent compaction of waste materials via heat pressing. Methods are also disclosed for using the disclosed canisters as hot isostatic pressing (HIP) cans to HIP materials contained therein and to treat contaminated ion exchange materials, such as radioactively contaminated HEPA filters. [Background technology]

[0003] background Ion exchange is one of the most common and effective treatment methods for removing radioisotopes from contaminated liquid waste streams. Despite its advanced stage of development, various aspects of ion exchange technology are being investigated in many countries to improve its efficiency and economics in its application to radioactive waste management. Spent ion exchangers are often considered problematic waste, requiring special approaches and precautions during immobilization to meet acceptance criteria for disposal.

[0004] For example, spent ion exchange resins and media can be processed in several ways where the media is removed from the housing (cartridge) either by dissolution or physical removal, which requires a handling process, which is problematic due to the hazards associated with handling radioactive materials.

[0005] Some proposed methods for treating spent ion exchange media include incineration of the resin to produce ash, which can then be immobilized in cement, bitumen, polymer, glass, or ceramic. Alternatively, they can simply be encapsulated in high-integrity containers. However, each of these options has drawbacks. For example, cement is readily available and inexpensive. It is also compatible with a wide range of materials and has excellent radiation stability. However, it is known to expand due to the presence of organic bead resins, which can lead to cracking of the cement-containing matrix. Additionally, this can lead to problems with low waste loading. Therefore, the volume of the final waste form generally exceeds the original waste volume. It also has moderate leaching resistance for many radionuclides, such as cesium.

[0006] Regarding bitumen-based immobilization, the material is known to have good leaching resistance and can handle good waste loads. However, the waste forms are known to soften at moderate temperatures and therefore require a container to maintain structural stability. Additionally, if there is prolonged contact with moisture, the organic bead resin can expand and damage the waste forms. Therefore, the organic waste forms are combustible and subject to biodegradation. It also has lower radioactivity stability than cement.

[0007] Regarding the use of polymer-based immobilization, a wide variety of polymers are available, many of which have good leaching resistance. However, polymers are generally more expensive than bitumen or cement. In addition, the polymerization reaction can be affected by trace amounts of materials in the waste. In addition, polymers generally have lower radiation stability than cement.

[0008] As explained, each known potential matrix has limitations. Furthermore, the type of ion exchange material also has limitations. For example, organic ion exchange resins decompose with prolonged exposure to radiation. As a result, the option of incinerating the organic resins to ash, while effective for stabilizing chemical compounds, does not immobilize the radioactive elements and therefore requires further processing.

[0009] In the case of inorganic ion-exchange media, radioactive elements can be extracted via chemical routes. Alternatively, once removed from the enclosure, the media can be directly processed using one of several proposed techniques, such as cementation or vitrification. However, existing techniques have substantial problems associated with their development, including large waste volume increases, high potential for contamination spread during handling of loose materials, radioactive gas release during the vitrification process, chemical incompatibility with existing cement matrices, and low retention of important radionuclides in cementitious waste forms. Thus, while inorganic ion-exchange media are more resistant to radiation damage, they are not currently available in forms suitable for long-term storage or disposal.

[0010] While ion exchange systems are a highly effective method of reducing short-term risks and preventing the spread of radioactivity, their intermediate storage and long-term disposal options pose their own challenges. These concerns include the potential risk of H2 generation via water radiolysis, the production of flux via self-heating of spent ion exchangers leading to container pressurization, the release of adsorbed radionuclides due to altered solution chemistry, corrosion of intermediate storage packages in brine solutions, and the dispersion risks inherent in storing granular materials.

[0011] To address and eliminate the aforementioned problems, an in-vessel ion exchange system is described that is designed to be dehydrated after use for increased stability during intermediate storage and then consolidated into a stable monolithic waste form via a hot isostatic press. The disclosed system will reduce the risk of contamination spread during processing and exchange of the exchange medium while minimizing handling equipment requirements. This is accomplished using a purpose-designed cartridge system that is suitable for performing all three operations. Summary of the Invention [Means for solving the problem]

[0012] Abstract While aspects of the present application overcome the shortcomings and limitations of the prior art, other improvements not recognized in the prior art are also disclosed. For example, to achieve desired advantages and overcome one or more of the shortcomings described above, a canister for intermediate storage and subsequent compaction of waste via a hot press is described. In one embodiment, the canister includes at least one ion exchange material and is configured to receive the ion exchange material after exchange with contaminant ions without releasing the contaminant ions and compact it via a hot isostatic press.

[0013] Also disclosed is a method for immobilizing waste in a dense monolith, the method comprising contacting a fluid waste with an ion exchange material, the ion exchange material being located in a canister, evacuating the canister, and hot isostatic pressing (HIP) the canister until it collapses under HIP conditions. In one embodiment, the HIP conditions include heat, pressure, and time sufficient to compact and immobilize the waste into the dense monolith. For example, the present application provides the following: (Item 1) 1. A canister for intermediate storage and subsequent compaction of waste via hot isostatic pressing, the canister comprising at least one ion exchange material therein, storing the ion exchange material after exchanging the contaminant ions without releasing the contaminant ions; The ion exchange material is consolidated via a hot isostatic press. The canister is configured as follows: (Item 2) Item 10. The canister of item 1, wherein the ion exchange material is located within the canister as an integral part of the canister or within a filter or cartridge housed inside the canister. (Item 3) 3. The canister of claim 2, wherein the at least one ion exchange material comprises a plurality of different types of ion exchange material. (Item 4) 4. The canister of claim 3, wherein the plurality of different types of ion exchange material are in the form of different layers on the interior surface of the canister, different media located within the canister, different filters, different cartridges, or a combination thereof. (Item 5) 5. The canister of claim 4, wherein the different types of ion exchange materials provide a sequential ion exchange mechanism. (Item 6) Item 10. The canister of item 1, wherein the canister is made from an alloy of steel that can be inductively bonded. (Item 7) Item 14. The canister of item 1, further comprising at least one heating element located on an exterior surface of the canister, wherein heating occurs by inductive coupling, resistive heating, radiative heating, or a combination thereof. (Item 8) 10. The canister of claim 1, further comprising at least one port for attaching to a vacuum device, for introducing fluids into, or removing fluids from, the canister. (Item 9) 9. The canister of claim 8, wherein the fluid comprises a compressed gas or a liquid selected from water, a slurry, or a solution. (Item 10) 10. The canister of claim 9, wherein the slurry or solution incorporates at least one additive that aids in converting the ion exchange material into a stable waste form after hot isostatic pressing. (Item 11) Item 1. The canister of item 1, further comprising at least one additive selected from a zeolite mineral, a silicate mineral, SiO2, TiO2, phosphoric acid, alumina borosilicate glass, borosilicate glass, silica titanate glass, iron phosphate glass, phosphate glass, lithium oxide, lithium fluoride, calcium fluoride, sodium fluoride, sodium fluorosilicate, or a combination thereof. (Item 12) 12. The canister of claim 11, wherein the at least one additive is an integral part of the canister or is added to the canister via an inlet prior to hot isostatic pressing. (Item 13) Item 12. The canister of item 11, wherein the at least one additive is in the form of beads, the beads comprising glass, ion exchange resin, or a combination thereof. (Item 14) 12. The canister of claim 11, wherein the additive comprises glass beads and the ion exchange material is in the form of a coating on the surface of the glass beads. (Item 15) Item 14. The canister of item 1, further comprising a shield within the wall to prevent emission of ionizing radiation from the canister. (Item 16) Item 1, the canister further comprising a first lid for storing contaminated ion exchange material within a sealed housing, the first lid being replaceable with a second lid configured to receive the contaminated ion exchange material within the sealed housing, the second lid being used for hot isostatic pressing. (Item 17) 2. The canister of claim 1, further comprising a split valve port or at least one other opening designed to maintain contamination, which is hot isostatically pressed and can provide contamination control during cartridge changes. (Item 18) 2. The canister of item 1, configured to be sealed while hot and to form a partial vacuum upon cooling. (Item 19) 2. The canister of claim 1, further comprising at least one port for a filter that allows fluid to be removed from the canister but retains solids within the canister. (Item 20) 20. The canister of claim 19, further comprising at least one plate, baffle, or pipe that directs the flow of the aqueous fluid so that it is uniform across the ion exchange material. (Item 21) 2. The canister of item 1, further comprising an inlet for a particulate filter made from sand or other granular material. (Item 22) 1. A method for immobilizing waste in a dense monolith, comprising: contacting the fluid waste with an ion exchange material, the ion exchange material being located in a canister; evacuating the canister; hot isostatic pressing (HIP) the canister until crushed, said conditions including heat and pressure sufficient to consolidate the ion exchange material containing the waste material into a dense monolith; A method comprising: (Item 23) 23. The method according to item 22, wherein the HIP conditions include a temperature ranging from 100°C to 1,400°C and a treatment pressure ranging from 15 to 100 MPa for a time ranging from about 1 to 16 hours. (Item 24) 23. The method of claim 22, wherein the fluid waste material contacted with the ion exchange material is a gas or liquid contaminated with radioactive material. (Item 25) 23. The method of claim 22, further comprising inserting the canister into an overpack container prior to hot isostatic pressing. (Item 26) 23. The method of claim 22, further comprising the step of adding at least one additive to the container prior to ion exchange or after ion exchange but prior to hot isostatic pressing, the at least one additive being added in an amount sufficient to accomplish at least one of the following: repacking spent ion exchange material; or converting the ion exchange material after hot isostatic pressing into a dense monolith that immobilizes the waste material. (Item 27) 27. The method of claim 26, wherein the at least one additive comprises a zeolite mineral, a silicate mineral, SiO, TiO, phosphoric acid, alumina borosilicate glass, borosilicate glass, silica titanate glass, iron phosphate glass, phosphate glass, lithium oxide, lithium fluoride, calcium fluoride, sodium fluoride, sodium fluorosilicate, or a combination thereof. (Item 28) 28. The method of claim 27, wherein the at least one additive is in the form of beads, the beads comprising glass, ion exchange resin, or a combination thereof. (Item 29) 28. The method of claim 27, wherein the at least one additive softens during the hot isostatic pressing and forms a glass phase that fills voids left by decomposition of the ion exchange media, and the glass phase cools and becomes part of the final waste form. (Item 30) 30. The method of claim 29, wherein the final waste form comprises radioactive ions immobilized in the glass phase. (Item 31) 23. The method of claim 22, further comprising the step of dehydrating the ion exchange material by pumping a fluid located in the canister, drying the canister, and sealing the canister prior to hot isostatic pressing. (Item 32) 32. The method of claim 31, wherein the step of pumping the fluid located in the canister prior to hot isostatic pressing is performed through a filter to ensure that the solids remain within the canister. (Item 33) Item 32. The method according to item 31, wherein the drying step is carried out at a temperature ranging from 100 to 700°C. (Item 34) 23. The method of claim 22, wherein the ion exchange material comprises a plurality of different types of ion exchange material that provide sequential ion exchange. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a prior art system used for the cementation process of spent ion exchange resin.

[0015] [Figure 2] FIG. 2 is a block diagram of a system according to the present disclosure for the treatment of spent organic ion exchange resins.

[0016] [Figure 3] Figure 3A is a drawing of a canister designed for direct hot isostatic pressing (HIP). Figure 3B further shows an embodiment of Figure 3A with a replaceable lid. Waste form additives can be added to either one.

[0017] [Figure 4] Figure 4A is a diagram showing an ion exchange medium having a waste form additive as a central core, and Figure 4B shows the medium combining the mixture of additives, waste ions, and ion exchange medium upon drying and application of heat and pressure to create the waste form. DETAILED DESCRIPTION OF THE INVENTION

[0018] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

[0019] Detailed Description of the Invention Applicants herein disclose canisters into which ion exchange material or filter systems may be housed at the end of the ion exchange material's useful life with the intention of using them as part of a treatment process. Accordingly, canisters housing ion exchange material are designed to encapsulate the contents during the HIP process.

[0020] A wide range of materials are available for ion exchange treatment of radioactive materials, such as radioactive liquids. These materials are available in various forms, have widely differing chemical and physical properties, and can be naturally occurring or synthetic. Ion exchange materials can be classified according to their suitability for different applications. Nuclear-grade organic ion exchange resins are typically used when liquids from primary circuits or fuel pools are purified. The type of material to be used is selected based on its ability to remove impurities and undesirable ions and control pH. Nuclear-grade ion exchangers are similar to commercial-grade resins but have more stringent specifications regarding particle size and composition. Organic resins are often used over several treatment cycles by eluting the absorbed radioisotopes with a suitable solution and then restoring the ion exchanger to its original ionic form before reuse.

[0021] Inorganic materials are commonly used for the treatment of liquid waste streams where very high chemical purity is not required. For example, inorganic ion exchange media can be used in systems where contaminated liquids are purified for certain recycling purposes or to reduce the level of radionuclide concentration in the liquid and allow its reclassification. Highly selective inorganic materials also allow ion exchange to be utilized when very high concentrations of competing ions are present. Inorganic ion exchangers are used almost exclusively in a once-through mode.

[0022] Applicants further disclose canisters / cartridges into which ion exchange media or filter systems are housed at the end of their useful life with the intention of using them as part of a treatment process. The canisters / cartridges described herein reduce or eliminate many of the process steps of alternative technologies, as can be seen in Figure 1 with respect to cementation. The media disclosed herein does not need to be removed or disassembled from its containing housing, eliminating handling and potential spread of contamination. Old, used ion exchange cartridges with degraded resins eliminate the problem of removing product that may no longer be granular or free-flowing.

[0023] In one embodiment, the canister housing the ion exchange material is designed to encapsulate the contents during the HIP process. Thus, we describe a canister that transitions from waste remediation to a stabilized waste form without the need for handling contaminated ion exchange material. This is particularly beneficial when ion exchange material is commonly contaminated with radioactive ions, other ionizing radiation, or other harmful contaminants. A key design feature facilitates pre-treatment steps and features that allow the material to be hot isostatically pressed (HIP), including all pre-treatment steps required to allow the material to be hot isostatically pressed, including the thermal pre-treatment process steps that must be performed on the ion exchange material.

[0024] For example, the canister is constructed to allow it to achieve the flexibility required to perform all of the functions from housing the ion exchange material even after it has done its job of adsorbing waste ions from the waste stream. To achieve this function, in some embodiments, the canister is made from an alloy of steel, such as stainless steel.

[0025] The inventors have shown that the described canisters can be used as HIP canisters to convert ion exchange material into a stable waste form. Thus, there is no need to remove contaminated ion exchange material from the canister prior to final disposal. In various embodiments, the canisters are designed to be heated to a temperature that allows for decomposition of the ion exchange resin, configured with appropriate ports and filters to remove excess moisture and unwanted volatiles, heated to dry the canister and its components, further calcined the components, hermetically sealed, etc., and then evacuated, held at a reduced pressure, and finally HIPed and compacted according to the HIP process.

[0026] Additionally, canisters can be designed to collapse under HIP conditions or to be inserted into an overpack canister to allow for HIP processing. An overpack canister is a device for containing radioactive and / or hazardous materials to be subjected to high pressure and / or high temperature. Non-limiting examples of overpack canisters that may be used are described in U.S. Pat. No. 8,662,338 (incorporated herein by reference). In its simplest form, an overpack canister is a can-in-can design in which a canister containing contaminated ion exchange material is placed inside another container for hot isostatic pressing. The outer can is configured to collapse in a controlled manner, such as by including a bellows or internal plate.

[0027] In another embodiment, the ion exchange media forms a coating on a glass or ceramic core. After the ion exchange is spent, during the HIP process, the core melts and reacts with the ion exchange media, forming a waste form.

[0028] In one embodiment, a canister for intermediate storage and subsequent compaction of waste materials via hot isostatic pressing is described. The interior of the canister contains at least one ion exchange material. In various embodiments, the ion exchange material is an integral part of the canister. For example, the ion exchange material may be located as a coating on the wall of the canister.

[0029] In another embodiment, the ion exchange material may be located in a filter or cartridge housed inside the canister. In one embodiment, the ion exchange material comprises multiple different types of ion exchange material depending on the ions that need to be separated. Thus, in some embodiments, the multiple different types of ion exchange material are in the form of different layers on the interior surface of the canister, different media located within the canister, different filters, different cartridges, or a combination thereof. As one skilled in the art will appreciate, different types of ion exchange material are beneficial when attempting to achieve a sequential ion exchange mechanism.

[0030] In some embodiments, the canisters described herein are configured to contain the ion exchange material after exchange with the contaminant ions without releasing the contaminant ions. For example, in some embodiments, the canister further includes shielding in the wall to prevent the release of ionizing radiation from the canister. The canister is also configured to compact the material via a hot isostatic press, even with the additional shielding.

[0031] The canisters described herein may further comprise at least one heating element located on an exterior surface or shell of the canister, wherein heating occurs by inductive coupling, resistive heating, radiative heating, or a combination thereof.

[0032] The canister may further comprise at least one port for attachment to a vacuum device or for introducing or removing a fluid from the canister. For example, the fluid may comprise a compressed gas or a liquid selected from water, a slurry, or a solution. In some embodiments, compressed gas is used for gas flow while heated to allow for washing of decomposition products. The vacuum and gas flow through while heated to allow for washing of decomposition products. In some embodiments, the canister further comprises at least one plate, baffle, or pipe to direct the flow of the aqueous fluid uniformly across the ion exchange material.

[0033] In some embodiments, the slurry or solution may be used to introduce at least one additive that aids in converting the ion exchange material into a stable waste form after hot isostatic pressing.

[0034] Non-limiting examples of the at least one additive are selected from zeolite minerals, silicate minerals, SiO2, TiO2, phosphoric acid, alumina borosilicate glass, borosilicate glass, silica titanate glass, iron phosphate glass, phosphate glass, lithium oxide, lithium fluoride, calcium fluoride, sodium fluoride, sodium fluorosilicate, or combinations thereof. The at least one additive may be an integral part of the canister or may be added to the canister via an inlet prior to hot isostatic pressing.

[0035] In some embodiments, at least one additive is in the form of beads, and the beads comprise glass, an ion exchange resin, or a combination thereof. For example, the additive comprises glass beads, and the ion exchange material is in the form of a coating on the surface of the glass beads.

[0036] In another embodiment, the canister can be lined with glass / additives, so that during the HIP process the glass softens and fills the void space left by the ion exchange media and / or filters. The glass / additives also become part of the waste mixture, forming a durable waste form for disposal and immobilization of radioactive species, and can be designed to protect the steel canister from corrosion in saltwater solutions.

[0037] For example, it is possible that a canister can be loaded with glass / additives along with ion exchange media. In some embodiments, the glass / additives can be in the form of beads that form a two-dimensional (2-D) or three-dimensional (3-D) network within the can. During the HIP process, the additives become waste form.

[0038] The canister may further comprise a first lid for storing the contaminated ion exchange material within the sealed housing, the first lid being interchangeable with a second lid configured to receive the contaminated ion exchange material within the sealed housing, the second lid being used for hot isostatic pressing.

[0039] The canisters described herein are further hot isostatically pressed and include a split valve port or at least one other opening designed to maintain contamination, which can provide contamination control during cartridge changes.

[0040] In some embodiments, the canister is configured to be sealed while hot and form a partial vacuum upon cooling. The canister may further include at least one port for a filter that allows fluid to be removed from the canister but retains solids within the canister. The canister may further include an inlet for a particulate filter made from sand or other granular material.

[0041] Also disclosed is a method for immobilizing waste material in a dense monolith, the method comprising contacting the fluid waste material with an ion exchange material, the ion exchange material being located in a canister, evacuating the canister, and hot isostatically pressing (HIP) the canister until it collapses under HIP conditions. The HIP conditions include heat and pressure sufficient to consolidate the ion exchange material containing the waste material into a dense monolith. For example, the HIP conditions include temperatures ranging from 100°C to 1,400°C and process pressures ranging from 15 to 100 MPa for times ranging from about 1 to 16 hours.

[0042] In some embodiments, the fluid waste that is contacted with the ion exchange material is a gas or liquid that is contaminated with radioactive material.

[0043] When necessary or desired, the methods described herein may further include the step of inserting the canister into an overpack container prior to hot isostatic pressing.

[0044] In certain embodiments, the methods described herein further include adding at least one additive to the container prior to ion exchange or after ion exchange but prior to hot isostatic pressing, wherein the at least one additive is added in an amount sufficient to accomplish at least one of the following: repacking the spent ion exchange material or converting the ion exchange material after hot isostatic pressing into a dense monolith that immobilizes the waste material.

[0045] In some embodiments, the method includes adding at least one additive including a zeolite mineral, a silicate mineral, SiO, TiO, phosphoric acid, alumina borosilicate glass, borosilicate glass, silica titanate glass, iron phosphate glass, phosphate glass, lithium oxide, lithium fluoride, calcium fluoride, sodium fluoride, sodium fluorosilicate, or a combination thereof.

[0046] In certain embodiments, the method includes adding at least one additive, wherein the beads are in the form of beads, the additive comprising glass, an ion exchange resin, or a combination thereof.

[0047] The methods described herein, including the step of adding at least one additive, form a glassy phase that softens during hot isostatic pressing and fills the voids left by the decomposition of the ion exchange media, and the glassy phase cools to become part of the final waste form, which includes radioactive ions that are immobilized in the glassy phase.

[0048] The methods described herein further include dehydrating the ion exchange material by pumping the fluid located in the canister. In certain embodiments, the pumping of the fluid located in the canister can be performed through a filter to ensure that solids remain within the canister.

[0049] The dehydrating step is generally followed by drying the canister, such as at a temperature ranging from 100 to 700° C., prior to sealing the canister. Once dehydrated, dried, and sealed, the canister can be hot isostatically pressed. (Industrial Applicability)

[0050] The disclosed canisters enable straightforward scalability, providing improved safety and maximized waste volume reduction. This in turn enables custom ion exchange plants and emergency cleanup operations such as those required by the Fukushima disaster. The disclosed canisters also enable the replacement / expansion of surrounding capacity for aging ion exchange plants.

[0051] Applicants additionally disclose methods for storing and / or consolidating waste using the disclosed canisters and systems. In certain embodiments, the methods include contacting a waste form with an ion exchange medium. In a non-limiting embodiment, the waste form contacted with the ion exchange medium is a liquid, such as water contaminated with radioactive materials. The ion exchange material, which may be in the form of a media, cartridge, or filter located in a canister, is placed in a HIP system such that the canister becomes a HIP can. Depending on the HIP process, the canister collapses under HIP conditions, consolidating the material contained therein. In certain embodiments, the canister may be placed in an overpack canister prior to HIPing.

[0052] The HIP process is described in more detail in U.S. Pat. No. 8,754,282, which is incorporated herein by reference in its entirety. More specifically, as described in this patent, the HIP consists of a pressure vessel surrounding an insulated resistance-heated furnace. Treating radioactive calcinate using a HIP involves filling the container with waste, here the contaminated ion exchange media. The container is evacuated and placed in a HIP furnace, where the vessel is closed, heated, and pressurized. Pressure is typically provided via argon gas, which is also an efficient heat conductor under pressure. The combination of heat and pressure causes the waste to compact and solidify into a dense monolith.

[0053] HIP processes one can at a time to temperatures ranging from 100°C to 1,400°C, at process pressures ranging from 15 to 100 MPa. Cycle times for HIPing cans range from approximately 1 to 16 hours. Once removed from the HIP, the cans are allowed to cool to ambient temperature before being loaded into a waste canister. HIP temperatures may also be modified depending on the waste product. Variations in HIP conditions, such as temperature, pressure, and atmosphere, depending on the material being consolidated, are described in U.S. Patent Nos. 5,997,273 and 5,139,720, which are incorporated herein by reference.

[0054] The described canister offers several advantages not previously available. It provides an ion exchange system within a container that is designed to be dehydrated after use. This increases stability during intermediate storage and allows for subsequent consolidation of the waste into a stable, monolithic waste form via hot isostatic pressing (HIP). The disclosed canister therefore reduces the risk of contamination spread during processing and exchange of ion exchange media while minimizing handling equipment requirements. This is achieved using a purpose-designed canister that is suitable for performing all three operations.

[0055] Other embodiments of the invention will also be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope of the invention being indicated by the following claims.

Claims

1. 1. A method for immobilizing radioactive ions or other harmful contaminants from fluid waste in a dense monolith, said method comprising: removing radioactive ions or other harmful contaminants from fluid waste by contacting the fluid waste with an ion exchange material, the ion exchange material being located in a canister, the ion exchange material used to remove the radioactive ions or other harmful contaminants from the fluid waste being contaminated with the radioactive ions or other harmful contaminants; maintaining a reduced pressure by evacuating fluid within the canister; inserting the canister into an overpack container prior to hot isostatic pressing; hot isostatically pressing (HIP) the canister and the overpack container until crushed, the HIP conditions providing heat and pressure sufficient to consolidate the contaminated ion exchange material containing the radioactive ions or other hazardous contaminants into a dense monolith; A method comprising:

2. 10. The method of claim 1, wherein the HIP conditions provide a temperature ranging from 100°C to 1,400°C and a processing pressure ranging from 15 MPa to 100 MPa for a time ranging from about 1 hour to about 16 hours.

3. 10. The method of claim 1, wherein the fluid waste contacted with the ion exchange material is a gas or liquid contaminated with radioactive material.

4. 10. The method of claim 1, further comprising adding at least one additive to the canister prior to ion exchange or after ion exchange but prior to hot isostatic pressing, the at least one additive being added in an amount sufficient to accomplish at least one of: recharging spent ion exchange material; or, after hot isostatic pressing, converting the contaminated ion exchange material into a dense monolith that immobilizes the radioactive ions or other harmful contaminants.

5. The at least one additive may be a zeolite mineral, a silicate mineral, SiO ２ , TiO ２ 5. The method of claim 4, wherein the glass comprises a glass material selected from the group consisting of phosphoric acid, alumina borosilicate glass, borosilicate glass, silica titanate glass, iron phosphate glass, phosphate glass, lithium oxide, lithium fluoride, calcium fluoride, sodium fluoride, sodium fluorosilicate, and combinations thereof.

6. 6. The method of claim 5, wherein the at least one additive is in the form of beads, the beads comprising glass, ion exchange resin, or a combination thereof.

7. 6. The method of claim 5, wherein the at least one additive forms a glassy phase that softens during the hot isostatic pressing and fills voids left by decomposition of the ion exchange material, and wherein the glassy phase becomes part of the final waste form upon cooling.

8. 8. The method of claim 7, wherein the final waste form comprises radioactive ions immobilized in the glass phase.

9. 10. The method of claim 1, further comprising dehydrating the ion exchange material by pumping a fluid located in the canister, drying the canister, and sealing the canister prior to hot isostatic pressing.

10. 10. The method of claim 9, wherein pumping the fluid located in the canister prior to hot isostatic pressing is performed through a filter to ensure that solids remain within the canister.

11. 10. The method of claim 9, wherein drying is carried out at a temperature ranging from 100°C to 700°C.

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