Abstract: A method for reducing radiologically-contaminated waste is provided. The method comprises treating radiologically-contaminated surfaces and subsurfaces. The method comprises consolidating soil waste. The method comprises employing real-time scanning technology to classify waste based at least in part on a threshold of radiological contamination. The waste is sorted based on the classification. The waste is disposed of via at least one of different disposal routes, based at least in part on the classification.

Abstract: An amount-reduction, harmless, disposal method for heavy metal waste gypsum (HMWG), which belongs to the technical fields of recycling economy and environmental protection. The HMWG used as raw material is subjected to processes of smelting fluxpreparation, lead smelting, fuming, and geopolymeric gelling, to realize amount-reduction, harmless and resources recycling utilization of heavy metal waste gypsum. The smoke containing sulfur dioxide produced in the smelting process is sent to the acid making system, and the produced dust with heavy metal is sent to the dedicated system for heavy mental disposing. The smoke dust produced in the fuming process is returned to the lead smelting system. The secondary HMWG produced in the acid making system would be returned to the preparation process of smelting flux. And the final products would be sulfuric acid and geopolymer material.

Abstract: Using crystalline silica, mixed with cement powder, to reduce the heating of the cement paste caused by the hydration of said powder, during a process of packaging of radioactive waste, a formulation for the packaging of radioactive waste by cementing, which comprises such silica, a method for packaging radioactive waste implementing this formulation, and a package for packaging of radioactive waste which is obtained by this method.

Abstract: Using crystalline silica, mixed with cement powder, to reduce the heating of the cement paste caused by the hydration of said powder, during a process of packaging of radioactive waste, a formulation for the packaging of radioactive waste by cementing, which comprises such silica, a method for packaging radioactive waste implementing this formulation, and a package for packaging of radioactive waste which is obtained by this method.

Abstract: The present disclosure describes solid waste forms and methods of processing waste. In one particular implementation, the invention provides a method of processing waste that may be particularly suitable for processing hazardous waste. In this method, a waste component is combined with an aluminum oxide and an acidic phosphate component in a slurry. A molar ratio of aluminum to phosphorus in the slurry is greater than one. Water in the slurry may be evaporated while mixing the slurry at a temperature of about 140-200° C. The mixed slurry may be allowed to cure into a solid waste form. This solid waste form includes an anhydrous aluminum phosphate with at least a residual portion of the waste component bound therein.

Abstract: A method and apparatus for the stabilization and safe removal of buried waste that is tested and classified as being transuranic or not transuranic waste and disposed accordingly. The buried waste (usually in vertical pipe units) is enclosed in a casing and ground and mixed with the surrounding soil. This process allows for chemical reactions to occur that stabilizes the mixture. The entire process is contained within the casing to avoid contamination. In situ or external testing is done for radio isotopes to classify the waste. If it is classified as transuranic the waste is removed in a controlled way into a retrieval enclosure and disposed off in drums. If the waste is not transuranic then grout is introduced into the mixture, allowed to set and the resulting monolith is removed and buried in trenches.

Abstract: A method for filling a container with hazardous waste includes moving the container to a first location where a filling head adds the hazardous waste to the container, vents air from the container, and mixes the hazardous waste in the container. A lid is coupled to the container while it is at the first location.

Abstract: A method for preparing a composite material from a waste appearing as sludge is provided. The method comprises a step consisting in putting said waste appearing as sludge in contact with a dry cement mixture. Also provided are the thereby obtained composite material and the use of such a method for treating and/or inertizing wastes and notably industrial and/or radioactive wastes.

Abstract: The present invention discloses a method for solidifying and stabilizing waste acid including steps of condensing waste acid containing phosphoric acid to reduce the volume; mixing the condensed waste acid with waste acid containing fluoroboric acid to solidify and stabilize the mixed waste acid. The pH of the mixed acid is adjusted by adding barium hydroxide as a neutralizer. The efficiency of solidifying waste acid can be improved by partially granulating and by adding solidifying agent indirectly. The method of the present invention can prevent intensely exothermic reaction caused by adding solidifying agents. Furthermore, the method of the present invention is controlled in a temperature of 30 to 45° C. to improve the polymerization of the mixed waste acid so that the efficiency of solidification thereof can be also improved.

Abstract: The present invention discloses a method for solidifying and stabilizing waste acid including steps of condensing waste acid containing phosphoric acid to reduce the volume; mixing the condensed waste acid with waste acid containing fluoroboric acid to solidify and stabilize the mixed waste acid. The pH of the mixed acid is adjusted by adding barium hydroxide as a neutralizer. The efficiency of solidifying waste acid can be improved by partially granulating and by adding solidifying agent indirectly. The method of the present invention can prevent intensely exothermic reaction caused by adding solidifying agents. Furthermore, the method of the present invention is controlled in a temperature of 30 to 45° C. to improve the polymerization of the mixed waste acid so that the efficiency of solidification thereof can be also improved.

Abstract: Treatment of a radioactive waste stream is provided by adding sodium hydroxide (NaOH) and/or potassium hydroxide (KOH) together with a rapidly dissolving form of silica, e.g., fumed silica or fly ash. Alternatively, the fumed silica can be first dissolved in a NaOH/KOH solution, which is then combined with the waste solution. Adding a binder that can be a mixture of metakaolin (Al2O3.2SiO2), ground blast furnace slag, fly ash, or other additives. Adding an “enhancer” that can be composed of a group of additives that are used to further enhance the immobilization of heavy metals and key radionuclides such as 99Tc and 129I. An additional step can involve simple mixing of the binder with the activator and enhancer, which can occur in the final waste form container, or in a mixing vessel prior to pumping into the final waste form container, depending on the particular application.

Abstract: The present invention relates to a process for the solidification and stabilization of concentrated aqueous sodium hydroxide solution, characterized in that the following steps are carried out: a) a hydraulic binder containing blast furnace slag is mixed with said sodium hydroxide solution, in the presence of at least one additional source of calcium ions and/or magnesium ions and/or silica, to form a slurry, and b) the slurry is left to set to a solid product. The invention further relates to the solid product obtained by carrying out the process of the invention. The invention can be applied to the treatment of sodium hydroxide solutions that are radioactive or contaminated by other pollutants.

Abstract: A method for conditioning a contaminated ion exchange resin includes mixing the contaminated ion exchange resin with water and at least partly breaking up the contaminated ion exchange resin into water-soluble components or fragments through the use of an oxidizing agent added to the water. A resulting aqueous solution is consolidated with a binder, optionally after concentration by evaporation of water.

Abstract: The invention relates to the confinement of an alloy formed of actinide transuranic radioactive wastes and beryllium metal within a neutron moderating and reflecting apparatus to cause accelerated destruction (burning) of the actinide wastes. Waste actinides, including plutonium, neptunium, americium, and curium, emit alpha particles by radioactive decay. The alpha particles are converted into neutrons by the beryllium through an alpha-neutron (alpha, n) reaction. The neutrons developed by the alpha, n reaction are moderated by a surrounding layer of graphite, which allows the slowed neutrons to cause additional fission or decay events within the waste actinide alloy. This process is passive because the alpha particles that initiate the actinide burning are an intrinsic physical property of the actinides.

Abstract: An apparatus for encapsulating waste material (e.g radioactive sludge from nuclear processing plant) in a container (e.g Nirex box) for long term storage, comprising: a first storage vessel, for holding sludge; a second storage vessel, for holding encapsulation medium (e.g. cement based grout); an inline mixer (e.g. a static inline mixer), coupled for receiving sludge, and coupled to the second storage vessel, and producing, in use, a mixture of the sludge and grout; wherein the inline mixer is arranged for filling the container. Preferably, a dewatering unit (e.g. HydroTrans based), coupled for receiving sludge and outputting dewatered sludge to be mixed by the inline mixer. An encapsulation system comprising the encapsulation apparatus, and corresponding encapsulation methods, are also disclosed.

Abstract: The present disclosure relates to a process for recycling a sodium salt by decomposition of a sodium nitride liquid waste, comprising a neutralization step in which a nitric acid liquid waste or an off-gas having nitric acid dissolved therein which is produced through a wet reprocessing process comprising a dissolution step for dissolving a spent nuclear fuel in nitric acid is neutralized by adding or contacting the nitrate liquid waste or the off-gas to or with at least one sodium salt selected from the group consisting of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate, thereby yielding a sodium nitrate liquid waste; a sodium nitrate-decomposition step in which the sodium nitrate liquid waste is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt; and a recycle step for recycling the sodium salt into the neutralization step or wet reprocessing process.

Abstract: Cement-based composition for the embedding of a boron-containing aqueous solution, said composition being composed of a sulphoaluminate cement optionally comprising gypsum, and of a sand. Process for embedding, by cementation, of a boron-containing aqueous solution in which said aqueous solution is kneaded, mixed with said cement-based composition. Cement grout composition thus obtained.

Abstract: A system for filling a container with hazardous waste includes a primary confinement chamber that houses a lid handling mechanism and a filling head. The lid handling mechanism may be used to remove and/or recouple the lid to the container as part of the process of filling the container in such a way to ensure the exterior of the container is not contaminated by the hazardous waste. The filling head may be configured to add the hazardous waste to the container, mix the contents of the container, and/or vent air from the container. The system may include additional mechanisms in the primary confinement chamber to add dry cementitious material to the container, add premixed wet cementitious materials to the container, add cementitious material to seal off the top of the lid, and/or measure the level and test whether the contents of the container meet quality assurance requirements. The hazardous waste may include radioactive hazardous waste.

Abstract: Radiation shields and techniques for radiation shielding are provided. Bitumen substances, such as asphalt or tar, are mixed with radioactive waste, leaded glass, or a radioactive waste and leaded glass composite. In embodiments where the bitumen substance is mixed with leaded glass, the resulting mixture can be coated onto containers that house radioactive waste or the resulting mixture can be coated onto the outer surface of the radioactive waste.

Abstract: A hydrotalcite-like substance that is capable of ion exchange with target anions, being of small crystal size and that exhibits large basal spacing, excelling in anion exchange performance; a process for producing the same; and a method of immobilizing hazardous substances. A hydrotalcite-like substance is produced by mixing an acidic solution containing aluminum ions and magnesium ions with an alkaline solution containing an alkali to thereby synthesize a hydrotalcite-like substance, followed by, without ageing, water removal or neutralization. The molar ratio of aluminum ions and magnesium ions is preferably in the range of 1:5 to 1:2. Hazardous substances can be immobilized by pulverizing the hydrotalcite-like substance after synthesis and adding the powder to a subject, or adding a hydrotalcite-like substance in slurry form to a subject, or carrying out addition so as to cause the synthesis directly at the position of the subject.

Abstract: A method for shredding, blending, and packaging wastes so that the shipment of waste is acceptable for transportation and disposal. Containerized wastes, laden with fissile isotopes, such as that from sodium fluoride traps and granulated carbon collection assemblies, if not already conditioned, are conditioned for blending by shredding them to particle size and then blending the particles with a grout mix either in a reusable mixing vessel or in a disposable mixing vessel. The blend of waste and grout is selected to meet governmental and disposal site requirements for an acceptable waste shipment. If blended in a reusable vessel, the blended waste is transferred to shipping containers. The shipping containers are placed in shielded shipping casks for transportation to a disposal facility. The grout mix is a combination of grout and neutron poisons such as borated sand to prevent criticality.

Abstract: A method including a combination of intermediate storage and reprocessing is utilized to process spent nuclear fuel (SNF) and thereby effect a disposition of that SNF within a period of 300 years. The method includes five or more years of pool water storage wherein ninety-nine percent (%) of the fission wastes energy decays. The waste material is then stored in an air convention storage facility, before processing to separate Cesium and Strontium from the waste is effected. This air convection cooling may be done in convection air-cooled concrete casks. During 50 years of convection air-cooled storage the energy contained in the waste material declines another one half %. Thereafter, at any point the SNF is processed to sufficiently separate 99.999% of the 97% of actinides (approximately 95% U238 uranium, 1% U235 uranium, and 1% Pu239 plutonium) from the 3% fission wastes. Again, it is only necessary to provide approximately 99.

Abstract: The present invention relates to a nuclear waste disposal apparatus, a method of manufacturing the same, and a method of installing the same. The apparatus is manufactured by packing nuclear waste into a vessel, installing the vessel into a ring-shaped elastic body such as a discarded tire used on a truck or a large-sized bus, covering the vessel storing the nuclear waste therein with high-strength reinforced concrete, and installing pieces of structural steel in a space of the elastic body so that the apparatus can endure heavy loads and natural disasters such as earthquakes.

Abstract: Disclosed herein are a method for solidifying soil and industrial waste and a solidified material prepared thereby. The solidified material of soil and industrial waste is prepared by adding 2-6 parts by weight of a 3-5-fold dilution of a solidifying agent and 3-15 parts by weight of cement to 100 parts by weight of soil, industrial waste or a mixture of two or more thereof. The solidified material prepared according to this method has excellent density, strength, elasticity and durability, and thus can be used as a substitute for stone material. Also, it can be advantageously used in high-temperature and high-humidity areas, because external impact or pressure is relieved because it is absorbed by asphalt.

Abstract: The invention provides a cementitious composition comprising at least one sulphoaluminate cement which comprises a sulphoaluminate salt of an alkaline earth metal, the cementitious composition being essentially free of other cementitious components. Preferably the at least one sulphoaluminate salt of an alkaline earth metal comprises calcium sulphoaluminate and the cementitious composition additionally comprises at least one further salt of an alkaline earth metal, preferably calcium sulphate. The invention also provides a method for the encapsulation of materials, the method comprising treating the materials with the said at least one cementitious composition. Preferably, the materials which are encapsulated according to the method of the invention comprise waste materials generated in the nuclear processing industry comprising amphoteric reactive metals.

Abstract: The present invention relates to a process for the solidification and stabilization of concentrated aqueous sodium hydroxide solution, characterized in that the following steps are carried out: a) a hydraulic binder containing blast furnace slag is mixed with said sodium hydroxide solution, in the presence of at least one additional source of calcium ions and/or magnesium ions and/or silica, to form a slurry, and b) the slurry is left to set to a solid product. The invention further relates to the solid product obtained by carrying out the process of the invention. The invention can be applied to the treatment of sodium hydroxide solutions that are radioactive or contaminated by other pollutants.

Abstract: The invention relates to a method and system for the treatment of radioactive wastes produced as a consequence of the operation of nuclear power plants with pressurized water reactors and boron reactivity regulation accompanied by the simultaneous production of environmentally acceptable substances of, for example, borax, calcium-magnesium borates, boron acid and sodium hydroxide solutions.

Abstract: The mass, as that of any conventional concrete, is based on cement, aggregates, water and chemical additives that modify the properties of the concrete. According to the invention, the mass uses magnetite as an aggregate, with a highly continuous grain size in order to obtain an optimum homogeneity of the mass as well as a high density which provide an optimum barrier effect against radiation, allowing to reduce substantially the thickness of the wall required without affecting the barrier effect. The mass is ideally suited for obtaining poured concrete, concrete for bricks, concrete for slabs and dry mortar used to build radioactive premises such as radiotherapy and brachytherapy bunkers, radiology walls, etc.

Abstract: The invention provides a composite from which concrete featuring a sufficiently high heat resistance can be produced, as well as a high-safety sealed concrete cask having no opening (shielding defect) to offer high shielding performance that can prevent corrosion of an internal canister and release of radioactive material to the exterior. A concrete cask of the invention includes a cask body having a bottom but no lid in itself, and a lid which can open and close off a top opening of the cask body. Both the cask body and the lid are made of concrete manufactured by using a composite including Portland cement or blended cement containing Portland cement, which is mixed with water in such a manner that the content of calcium hydroxide falls in a range of 15% to 60% by mass after hardening through hydration reaction. Metallic heat-transfer fins are embedded in the cask body.

Abstract: This invention deals with multi-component composite materials and techniques for improved shielding of neutron and gamma radiation emitting from transuranic, high-level and low-level radioactive wastes. Selective naturally occurring mineral materials are utilized to formulate, in various proportions, multi-component composite materials. Such materials are enriched with atoms that provide a substantial cumulative absorptive capacity to absorb or shield neutron and gamma radiation of variable fluxes and energies. The use of naturally occurring minerals in synergistic combination with formulated modified cement grout matrix, polymer modified asphaltene and maltene grout matrix, and polymer modified polyurethane foam grout matrix provide the radiation shielding product. These grout matrices are used as carriers for the radiation shielding composite materials and offer desired engineering and thermal attributes for various radiation management applications.

Abstract: An injection and solidification operation as well as a kneading and solidification operation can be performed by a single facility. A decreased amount of radioactive secondary waste is generated. A solidifying agent paste is prepared by kneading a solidifying agent and additive water. The solidifying agent paste is injected into a solidifying container. The radioactive waste is charged into the solidifying container and kneaded.

Abstract: A method for grouting a decommissioned nuclear reactor containing residual water. A first, water-absorbent grout is used to grout the bottom portion of the reactor vessel. The water-absorbent grout is formed of cement and a water-absorbent particulate material, such as expanded perlite, exfoliated vermiculite or granulated bentonite. Excess water is absorbed by the particulate material, so that the residual water is incorporated in the fill material when it sets. A set retarder may be included to extend the time for uptake of residual water by the particulate material. Foam may also be included to reduce density and increase pumpability. The remaining, upper portion of the reactor vessel is grouted using lightweight cellular cement grout, lacking the water-absorbent particulate material, so that total weight of the fill remains low enough that the grouted vessel can be removed using the facility's installed crane system.

Abstract: A device for storing heat-generating hazardous material, particularly radio-active fuel for nuclear reactors, comprises a substantially cylindrical, reinforced concrete body (11) with a cylindrical through center passage (13) and a plurality of axially elongate, substantially cylindrical storage spaces for accommodating the hazardous material which are disposed around and parallel to and radially spaced spaced from the center passage. The storage spaces are formed by sealed storage vessels (21) containing a fluid coolant and made of a heat-conducting material and being encapsulated in the concrete body (11). Heat transferred inwardly from the storage vessels (21) is carried away from the device by air or other fluid coolant flowing upwardly in the center passage (13).

Abstract: An injection and solidification operation as well as a kneading and solidification operation can be performed by a single facility. A decreased amount of radioactive secondary waste is generated. A solidifying agent paste is prepared by kneading a solidifying agent and additive water. The solidifying agent paste is injected into a solidifying container. The radioactive waste is charged into the solidifying container and kneaded.

Abstract: A method for storing nuclear fuel in a container (10) including a concrete body and a fuel receiver embedded in the concrete body, comprises the steps of: providing formwork (62) for the concrete body and supporting the fuel receiver within the formwork; placing the formwork in an immersed position in a pool (54) containing a body of water; placing concrete in the immersed formwork (62); and removing the formwork with the concrete body cast therein from the pool (52).

Abstract: Apparatus for containing, transporting, and storing or disposing of radioactive machinery, including decommissioned nuclear reactor pressure vessels. An improved, economically-produced container allows easier handling and packaging of machinery within plants where the machinery has been installed, and offers improved shock absorption and attenuation characteristics, especially when packaging is complete, through the provision, for example, of integral fenders. The invention also includes methods of making the container.

Abstract: A new method for combining magnesium oxide, MgO, and magnesium dihydrogen phosphate to form an inexpensive compactible ceramic to stabilize very low solubility metal oxides, ashes, swarfs, and other iron or metal-based additives, to create products and waste forms which can be poured or dye cast, and to reinforce and strengthen the ceramics formed by the addition of fibers to the initial ceramic mixture.

Abstract: A device (10) for storage of hazardous material, especially heat-producing hazardous material, such as radioactive spent nuclear reactor fuel, comprises a substantially cylindrical reinforced concrete body (12) and has an axially elongate storage space (18) for the hazardous material. A prestressed reinforcement (17) having reinforcing members (28, 29) extending helically about the storage space (18) is provided in the concrete body (12) adjacent to the outer side thereof. Preferably, the reinforcing members (28, 29) are divided into two groups, one inside the other, the hand of the reinforcing members (28) of one of the groups being opposite to the hand of the reinforcing members (29) of the other group. Also preferably, the ends of the concrete body are provided with end covers (15, 16) in which the reinforcing members (28, 29) are anchored.

Abstract: A method is disclosed for constructing, verifying, and maintaining underground vaults that isolate and contain radioactive burial sites. The method employs a buoyant lift technique to isolate a block of soil containing the contaminates from the surrounding soil. An impermeable synthetic liner is embedded in the vault to enhance the integrity of the system. The integrity of the vault is monitored by a system of sensors placed both inside and outside of the sealed vault. The method eliminates the need to excavate or drill in the contaminated areas.

Abstract: Method and apparatus for containing, transporting, and storing or disposing of radioactive machinery, including decommissioned nuclear reactor pressure vessels. An improved, economically-produced container is provided which allows easier handling and packaging of machinery within plants where the machinery has been installed, and which provides improved shock absorption and attenuation characteristics, especially when packaging is complete. A reactor pressure vessel or similar item is disconnected from the remainder of the plant and external fittings are trimmed as close to flush with item's exterior as practicable. A storage and containment canister, optionally cut into at least two sections to ease handling and packaging, is placed nearby. The pressure vessel head or any other low-radioactive items are removed, and insulation and other items removed from the outside of the item are placed inside the item's body.

Abstract: Provided are an improved structural material for bullet traps and the like, a method of producing it, and a structure comprising it. The material is suitable for entraining and immobilizing projectiles and fine particles in a sticky gel. It is prepared by mixing cement with a thickener to form a dry mixture. Water is mixed with a fine aggregate in a mixer. The dry mixture is combined with the aqueous mixture in the mixer to form a slurry. Calcium phosphate and an aluminum compound are added, mixing each separately until homogeneous. The density of the mixture is measured and an aqueous foam is added to adjust the density to a pre-specified level. Fibers are mixed into the adjusted mixture to form a homogeneous slurry that may be poured into a mold or in place at a construction site. Upon curing, the material may be used as a structural component.

Abstract: An economical and efficient method for forming a waste containing monolith which meets applicable waste disposal laws, rules and regulations. Removable walls are attached to at least one side of the monolith, thereby forming an interior volume defined by the removable walls and at least one side of the monolith. Waste is placed within the interior volume, whereupon it is submerged in a flowable, curable, monolith forming material (typically concrete) by filling the interior volume with a monolith forming material, and allowing the monolith forming material to cure to a solidified state, thereby forming an expanded monolith integral with the existing monolith. The walls are then removed, thereby leaving the waste encased within said expanded monolith and allowing the removable walls to be reused for further expansion of the monolith.

Abstract: A new method for enhancing the physical and radiation shielding characteristics of phosphate ceramics, via the incorporation therein of isotopic boron compounds and bismuth, iron, and lead additives. The resulting material finds applications as physical and radiation shields and as building constituents in spent fuel- and waste containment-scenarios.

Abstract: A method of packaging a nuclear reactor vessel for decommissioning and removal, wherein closure plates are installed onto the vessel, concrete is injected into the vessel, shielding material is installed around the exterior of the vessel and the main nozzles of the vessel, the installed shielding materials are welded to themselves, the vessel is placed on shipping cradles and attached to longitudinal restraint mechanisms for transport.

Abstract: A process is provided for the treatment of mercury containing waste in a single reaction vessel which includes a) stabilizing the waste with sulfur polymer cement under an inert atmosphere to form a resulting mixture and b) encapsulating the resulting mixture by heating the mixture to form a molten product and casting the molten product as a monolithic final waste form. Additional sulfur polymer cement can be added in the encapsulation step if needed, and a stabilizing additive can be added in the process to improve the leaching properties of the waste form.

Abstract: A method of encapsulating hazardous waste materials including heavy metals such as arsenic, mercury, nickel and chromium residues, as well as radioactive materials. The method involves adding the hazardous waste material to a settable composition, forming a slurry, and allowing the slurry to set to encapsulate the waste material. The settable composition is a powdered flowable cement composition containing calcium carbonate and a caustic magnesium oxide. Tests conducted on the encapsulated material indicate that virtually none of the hazardous waste material is leached out of the set composition which has a concrete-like appearance.

Abstract: This invention is directed to methods for treating radioactive-containing waste materials. More specifically, the present invention relates to the prevention of radon emissions. Even more specifically, this invention relates to the prevention of radon emissions by encapsulating the radon in radon-generating waste matter using a chemical additive. Alternatively, the amount of radon escaping into the environment may be minimized by adjusting the shape of the carrier which stores the radon-generating waste matter. Additionally, the first two embodiments may be combined to ensure that the radon does not escape into the environment. Finally, polymer sealants may be used as an additional barrier layer.

Abstract: The present invention utilizes one or more processes to immobilize a waste that contains one or more of radionuclides, hazardous elements, hazardous compounds, and/or other compounds present in the waste. Each of the processes create a barrier against leaching and diffusion of the wastes. The first barrier is created by integrating the waste with an immobilizing mineral. The second barrier is a layer of non-radioactive or non-hazardous material that covers the first barrier. The second barrier may be created using an overgrowth procedure or by sintering. The third barrier is created by a rock or glass matrix that surrounds the first and/or second barriers. The fourth barrier is created by ensuring that the rock or glass has the same or similar composition as the indigenous rock at the disposal site. The resultant rock or glass matrix is in equilibrium with the groundwater or local hydrothermal solutions that are saturated with components of the indigenous rock of the disposal area.

Abstract: A polymer coating is applied to the surface of a phosphate ceramic composite to effectively immobilize soluble salt anions encapsulated within the phosphate ceramic composite. The polymer coating is made from ceramic materials, including at least one inorganic metal compound, that wet and adhere to the surface structure of the phosphate ceramic composite, thereby isolating the soluble salt anions from the environment and ensuring long-term integrity of the phosphate ceramic composite.

Abstract: Known phosphate ceramic formulations are improved and the ability to produce iron-based phosphate ceramic systems is enabled by the addition of an oxidizing or reducing step during the acid-base reactions that form the phosphate ceramic products. The additives allow control of the rate of the acid-base reactions and concomitant heat generation. In an alternate embodiment, waste containing metal anions are stabilized in phosphate ceramic products by the addition of a reducing agent to the phosphate ceramic mixture. The reduced metal ions are more stable and/or reactive with the phosphate ions, resulting in the formation of insoluble metal species within the phosphate ceramic matrix, such that the resulting chemically bonded phosphate ceramic product has greater leach resistance.