Abstract: Provided are a silicotitanate molded body having high strength and reduced generation of fine powder, a production method thereof, an adsorbent comprising the silicotitanate molded body, and a decontamination method of radioactive cesium and/or radioactive strontium by using the adsorbent. The silicotitanate molded body comprises: crystalline silicotitanate particles that have a particle size distribution in which 90% or more, on volume basis, of the particles have a particle size within a range of 1 ?m or more and 10 ?m or less and that are represented by a general formula of A2Ti2O3(SiO4).nH2O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium.

Abstract: A decontamination method that includes the steps of decontaminating an object containing radioactive contaminated metals or alloys with a chemical decontamination agent including sulfuric acid (H2SO4) and forming a Ba or Sr precipitate by adding a Ba or Sr cation and a hydroxylion or halogen anion salts to the decontamination waste water.

Abstract: A method includes: a pre-treatment step of mixing radiocontaminated grains and a sodium phosphate-based dispersant; and a decontamination step of mixing the radiocontaminated grains processed by the pre-treatment step and paper sludge-derived sintered carbonized porous grains so as to incorporate radioactive 134Cs and 137Cs of the radiocontaminated grains in the sintered carbonized porous grains.

Abstract: The invention relates to the field of environmental protection, more specifically to the field of processing radioactive waste, and can he used for the safe and effective handling of a large quantity of liquid radioactive waste of various activity levels that has been formed as the result of decontaminating protective equipment of boxes and chambers, and makes it possible to decrease the volume of stored waste by solidifying same and incorporating same into a ceramic matrix. For this purpose, radioactive solutions after decontamination of surfaces of protective equipment are evaporated as alkaline and acidic solutions containing sodium hydroxide, potassium permanganate, oxalic acid, and nitric acid until a solid residue forms, and are calcined, and the calcinate is mixed with components of a fusion mixture containing oxides of titanium, calcium, iron (III), zirconium, and manganese (IV) and aluminum in a specified ratio, and fused.

Abstract: A method for treating before calcination a nitric aqueous solution comprising at least one radionuclide and ruthenium is provided. The method comprises a step for adding to the solution a compound selected from lignins, lignocelluloses, optionally as salts and mixtures thereof.

Abstract: Method of immobilizing nuclear waste comprising: a mixing step during which nuclear waste is mixed with a mineral composition and water, a drying step during which the mixture obtained in the mixing step is dried so as to form an immobilizing matrix, characterized in that the mineral composition is obtained by a manufacturing process that comprises the steps consisting of: preparation of a base comprising a predetermined quantity of a mineral material synthesized by at least one part of a living structure selected from the vegetable kingdom, animal kingdom and/or microorganisms; and treatment of said base so as to convert it into an inactivated material with a predefined texture.

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 of preparing a simple ceramic ingot of a spent filter having radioactive cesium trapped therein, and a ceramic ingot of a spent filter having improved properties such as leach resistance, thermal stability, and cesium content are provided. The method includes grinding and mixing a spent filter having cesium trapped therein, adding a solidifying agent, and sintering the spent filter. The method of preparing a ceramic ingot of a spent filter can be useful in preparing the ceramic ingot of the spent filter from only the spent filter by means of simple grinding and sintering, and in preparing the ceramic ingot of the spent filter by adding a small amount of a solidifying agent. The ceramic ingot of the spent filter has a high density and improved thermal stability, and shows improved leach resistance since a leach rate of a radioactive material is remarkably low. Therefore, the spent filter having radioactive cesium trapped therein can be effectively used to prepare a stable ceramic ingot.

Abstract: Disclosed herein is a method for preparing a ceramic waste form containing radioactive rare-earth and transuranic oxide, and the ceramic waste form with enhanced density, heat-stability, and leach resistance prepared by the same.

Abstract: Disclosed is a process of stabilizing spent filter material that comprises mixing the filter media with a dry media to produce a composition having a moisture content that is sufficiently low to retard microbial growth. The composition comprises spent filter media and a dry material, and preferably comprises diatomaceous earth. Soil is treated by adding the composition as a top dressing, soil amendment, or the like.

Abstract: The present disclosure relates to a method of consolidating a calcine comprising radioactive material, the method comprising mixing 60-80% (by weight) of a radionuclide containing calcine with at least one non-radioactive additive, such as an oxide, and hot isostatic pressing the mixture to form a stable monolith of glass/ceramic. In one embodiment, the ratio of radionuclide containing calcine to additives is about 80:20 by weight, wherein the non-radioactive additive comprises oxides such as BaO, CaO, Al2O3, TiO2, SiO2 and others, that combine with the waste elements and compounds to form a ceramic mineral or glass/ceramic material, after hot isostatic pressing. Non-limiting examples of mineral phases that may be formed are: hollandite (BaAl2Ti6O16), zirconolite (CaZrThO7), and perovskite (CaTiO3).

Abstract: Disclosed herein is a method for preparing a ceramic waste form containing radioactive rare-earth and transuranic oxide, and the ceramic waste form with enhanced density, heat-stability, and leach resistance prepared by the same.

Abstract: An adsorbent for radioelement-containing waste includes spherical layered double hydroxide (A) or spherical metal hydroxide (B). (A) is a nonstoichiometric compound represented by general formula (a) or (b): [M2+1-xM3+x(OH)2]x+[An?x/n.mH2O]x???(a), [Al2Li(OH)6]x+[An?x/n.mH2O]x???(b) where 0.1?x?0.4, 0<m. The n represents a natural number of 1 to 4, M2+ represents at least one divalent metal, M3+ represents at least one trivalent metal, and An? represents at least one n-valent ion-exchangeable anion. (B) contains a metal selected from the group of Group II, Group IV, Group V, Group VI, Group XI, Group XII, and Group XIII of the periodic table, and the group of Mn, Fe, Co, Ni, Pb, and Bi. This adsorbent efficiently adsorbs and collects volatile iodine, a radioactive anion in wastewater, etc. providing a crack-resistant solidified article after a solidification treatment, and effectively confines the radioelement-containing waste with long-term stability.

Abstract: An adsorbent for radioelement-containing waste composed of the following spherical layered double hydroxide (A) or spherical metal hydroxide (B) is provided. (A) is a nonstoichiometric compound represented by general formula (a) or (b): [M2+1-xM3+x(OH)2]x+[An?x/n.mH2O]x? . . . (a), [Al2Li(OH)6]x+[An?x/n.mH2O]x? . . . (b) wherein 0.1?x?0.4, 0<m, n represents a natural number of 1 to 4, M2+ represents at least one divalent metal, M3+ represents at least one trivalent metal, and An? represents at least one n-valent ion-exchangeable anion, and (B) is a spherical metal hydroxide containing a metal selected from the group consisting of the metal atoms belonging to Group II, Group IV, Group V, Group VI, Group XI, Group XII, and Group XIII of the periodic table, and the group consisting of Mn, Fe, Co, Ni, Pb, and Bi.

Abstract: A method of stabilizing nuclear material is disclosed. Oxides or halides of actinides and/or transuranics (TRUs) and/or hydrocarbons and/or acids contaminated with actinides and/or TRUs are treated by adjusting the pH of the nuclear material to not less than about 5 and adding sufficient MgO to convert fluorides present to MgF2; alumina is added in an amount sufficient to absorb substantially all hydrocarbon liquid present, after which a binder including MgO and KH2PO4 is added to the treated nuclear material to form a slurry. Additional MgO may be added. A crystalline radioactive material is also disclosed having a binder of the reaction product of calcined MgO and KH2PO4 and a radioactive material of the oxides and/or halides of actinides and/or transuranics (TRUs). Acids contaminated with actinides and/or TRUs, and/or actinides and/or TRUs with or without oils and/or greases may be encapsulated and stabilized by the binder.

Abstract: Radioactive cesium is confined in a hollandite structure formed by a process that does not require reducing conditions.

Abstract: A ceramic waste immobilizing material for the encapsulation of high level radioactive waste (HLW), e.g. resulting from the reprocessing of irradiated nuclear fuel. The ceramic waste immobilising material enables waste ions from at least fission products in irradiated nuclear fuel to be dissolved in substantially solid solution form. The ceramic waste immobilising medium has a matrix comprising phases of hollandite, perovskite and zirconolite in which the waste ions are dissolved. The invention also includes a method of immobilizing HLW from reprocessed nuclear fuel assemblies comprising the steps of mixing a liquor containing the HLW with a precursor material comprising oxides or oxide precursors of at least titanium, calcium and barium to form a slurry, drying the slurry, and calcining the dried slurry under a reducing atmosphere to form a powder comprising 30–65 weight % waste.

Abstract: The invention relates to a confinement matrix for the storage or incineration of at least one long-life radioactive element, comprising at least one crystalline boron compound of a rhombohedral structure including the long-life radioactive element(s). The boron compound may be of the B3Si, B6O or B4C type.

Abstract: A process is disclosed for the pyrolysis and gasification of waste materials, in particular of special and/or hazardous waste materials, comprising a gasification and melting step, a step of treatment of the mixture of the obtained gases, and a vitrification step, wherein said steps provide for the following passages: a) the material to be treated, at a temperature comprised between 1300 and 1500° C.

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 method and system for increasing the waste loading of vitrified nuclear waste includes a plasma mass filter and a heating apparatus. The plasma mass filter is used first to collect radioactive particles from a multi-species plasma. The radioactive particles are then placed, together with a frit, in crucibles. The crucibles are then induction heated to fuse the radioactive elements with the frit to form a melted mixture which is then cooled to form vitrified waste having relatively high waste loading.

Abstract: Encapsulating calcined radioactive waste in strong, corrosion-resistant spheres of dimensions such that heat from the radiation melts the ice at a rate which brings the spheres to the bottom of the permanent icefield in a relatively short time, with the resulting waste ultimately being no more hazardous than natural uranium ore.

Abstract: This invention relates to a method for conditioning a waste constituted of an aqueous solution of sodium hydroxide NaOH of 3 to 10 M, possibly radioactive. The method is as follows: a) a metakaolin powder is added to the aqueous solution such that a suspension is obtained capable of solidifying and forming a crystalline phase of the zeolite A type; b) the suspension is introduced into a mould; c) the suspension is left to solidify in the mould in order to obtain a moulded solid product based on zeolite A; d) the moulded product is dried; and e) the zeolite A phase is converted into a nepheline type phase by heat treatment at a temperature of 1000° C. to 1500° C.

Abstract: A new method for combining elemental iron and other metals to form an inexpensive ceramic to stabilize arsenic, alkaline red mud wastes, swarfs, and other iron or metal-based additives, to create products and waste forms which can be poured or dye cast.

Abstract: A device for improving waste vitrification in a disposable canister, the process for using the device, and the process for making the device. The disposable canister, also known as a module, has outer and inner containers with thermal insulation therebetween. The device includes an inner container of graphite having a layer of pyrographite on its external wall. The outer container is typically made of stainless steel. The inner container is heated, typically by induction, to melt the frit and waste. The melted mixture is then cooled to form a vitrified product in the module. The fabrication of the pyrographite coating on the inner container involves heating the container to about 1500 degrees centigrade in a methane atmosphere, then cooling the container to ambient temperature.

Abstract: A method for removing actinide contaminants (uranium and thorium) from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents are added to precipitate the thorium as thorium oxide and/or the uranium as either uranium oxide or as a diuranate salt. The precipitated materials are filtered, dried and packaged for disposal as radioactive waste. About 90% of the thorium and/or uranium present is removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 0.1 ppm of thorium or uranium.

Abstract: The invention involves a process for containment of industrial wastes, particularly nuclear wastes, in apatite ceramics. This process involves preparing a homogeneous mixture of powders which can form an apatite matrix, introducing the waste into this mixture, compacting it under a pressure of 100 to 500 MPa at room temperature, and subjecting it to hydrothermal processing at low temperature (100 to 500° C.) in the presence of water in a sealed chamber.

Abstract: Building bricks and tiles are made by mixing 60% to 75% clay, 20% to 40% sludge and 1% to 10% sand, all percentages being by weight of the total composition. This process utilizes industrial waste products to provide building materials which are lighter and stronger than conventional materials.

Abstract: A ceramic composition made from waste materials and a method for manufacturing the same are disclosed. The ceramic composition comprises between 5 and 75 by weight part of a solid stated waste material including heavy metals, between 15 and 45 by weight part of a fly ash and between 5 and 55 by weight part of a clay. The ceramic composition is manufactured by compositely stabilizing various waste materials and is available for a building material or an engineering material. Therefore, the waste materials are effectively recycled without causing environmental pollution.

Abstract: Disclosed is a process for making a ceramic composition for the immobilization of actinides, particularly uranium and plutonium. The ceramic is a titanate material comprising pyrochlore, brannerite and rutile. The process comprises oxidizing the actinides, milling the oxides to a powder, blending them with ceramic precursors, cold pressing the blend and sintering the pressed material.

Abstract: This disclosure sets forth a method for processing metal waste incorporating substantial zirconium as exemplified by nuclear fuel rods which include enriched uranium and other nuclear products. This process contemplates conversion of the zirconium and other constituents into oxides by mixing with an acid, subsequently forming a solution or a gel which is either dried or frozen, thereby yielding a green shaped body. The green body is thereafter sintered to form a dimensionally and structurally stable monolith for disposal.

Abstract: Organic materials are mixed with metal oxide, such as hydrated metal oxides, prior to or during heat treatments in aerated or oxygenated environments to stabilize thermal decomposition or incineration of the organic materials and to suppress the emission of volatile, hazardous organic compounds. The organic materials may be ion exchange resins and polymeric sorbents, for example, and include contaminated materials such as hazardous wastes. The hydrated metal oxides may be hydrated ferric oxide, hydrated aluminum oxide or hydrated titania oxide, for examples. Ferrihydrite is preferred. The heat treatment may be a preparation for a waste disposal process, such as immobilization in ferric oxide, cement, concrete, a polymer, bitumen or glass, for example. Immobilization processes in ferric oxide are also discussed, including the use of additives such as magnesium oxide, ammonium dihydrogen phosphate and phosphoric acid, enabling consolidation at room temperature and pressures less than 15,000 psi.

Abstract: The AVS invention provides for an apparatus and process for its practice involving the vitrification of waste materials, such as nuclear waste, inside a disposable canister. The preferred embodiment of the process includes a canister having outer and inner containers with thermal insulation therebetween. Solid frit sections are placed inside the inner container to create one or more regions for receiving waste. The waste is then loaded into the regions. The inner canister is heated to melt the frit and waste and mix them once molten. The melted mixture is then cooled to form a vitrified product in the module. In an alternative process, chunks of frit are mixed with waste and loaded into the empty canister. The mixture is then melted and cooled inside the disposal canister.

Abstract: A pumpable ceramic composition is provided comprising an inorganic oxide, potassium phosphate, and an oxide coating material. Also provided is a method for preparing pumpable ceramic-based waste forms comprising selecting inorganic oxides based on solubility, surface area and morphology criteria; mixing the selected oxides with phosphate solution and waste to form a first mixture; combining an additive to the first mixture to create a second mixture; adding water to the second mixture to create a reactive mixture; homogenizing the reactive mixture; and allowing the reactive mixture to cure.

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: Disclosed is a ceramic composition for the immobilization of actinides, particularly uranium and plutonium. The ceramic is a titanate material comprising pyrochlore, brannerite and rutile.

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.

Abstract: Processes for immobilizing solid contaminated materials, such as radioactive species, hazardous species, or combinations of both radioactive and hazardous species, comprise mixing the contaminated materials with hydrated ferric oxides, and then pressing the mixture at a temperature of at least about 150.degree. C. and gradually removing a large part of the water while under pressure to produce a solid composition. The water content of the mixture is adjusted if necessary. Contaminated materials dissolved or suspended in an aqueous solution can be immobilized by precipitating hydrated ferric oxide in the solution, and adjusting the water content and pressing, as above. In another process in accordance with the present invention, hydrated ferric oxides are deposited on metal surfaces. The deposited ferric oxide is pressed to produce a solid coating adhered to the surface, to retard corrosion. A ceramic body of ferric oxide composition may also be made in accordance with the present invention.

Abstract: A unique method for solidification of solutions containing boric acid and/or borates is disclosed in this invention. The boron species in the solutions are polymerized to form polyborates, and the solutions are then solidified by mixing with solidification agents which are prepared completely from inorganic materials. Therefore, the solid form produced by this method has no aging problem. The boron species in the solution are not merely wastes to be encapsulated or embedded, they take part in the solidification reaction and share a major portion of total reactants. Thus, the total volume of solid forms produced in this invention is less than 1/10 of that produced in conventional cementation.

Abstract: The present invention is directed to a process for reducing the volume of low level radioactive and mixed waste to enable the waste to be more economically stored in a suitable repository, and for placing the waste into a form suitable for permanent disposal. The invention involves a process for preparing radioactive, hazardous, or mixed waste for storage by contacting the waste starting material containing at least one organic carbon-containing compound and at least one radioactive or hazardous waste component with nitric acid and phosphoric acid simultaneously at a contacting temperature in the range of about 140.degree. C. to about 210 .degree. C.

Abstract: A method for immobilizing waste chlorides salts containing radionuclides and hazardous nuclear material for permanent disposal, and in particular, a method for immobilizing waste chloride salts containing cesium, in a synthetic form of pollucite. The method for synthesizing pollucite from chabazite and cesium chloride includes mixing dry, non-aqueous cesium chloride with chabazite and heating the mixture to a temperature greater than the melting temperature of the cesium chloride, or above about 700.degree. C. The method further comprises significantly improving the rate of retention of cesium in ceramic products comprised of a salt-loaded zeolite by adding about 10% chabazite by weight to the salt-loaded zeolite prior to conversion at elevated temperatures and pressures to the ceramic composite.

Abstract: A method to produce structural products from benign waste is provided comprising mixing pretreated oxide with phosphoric acid to produce an acid solution, mixing the acid solution with waste particles to produce a slurry, and allowing the slurry to cure. The invention also provides for a structural material comprising waste particles enveloped by an inorganic binder.

Abstract: A method for regulating the reaction temperature of a ceramic formulation process is provided comprising supplying a solution containing a monovalent alkali metal; mixing said solution with an oxide powder to create a binder; contacting said binder with bulk material to form a slurry; and allowing the slurry to cure. A highly crystalline waste form is also provided consisting of a binder containing potassium and waste substrate encapsulated by the binder.

Abstract: A method of treating a waste material, such as a radioactive waste material, by introducing the material into a high temperature reaction vessel such as an electric arc furnace. By controlling the reducing potential of the oxide phase formed in the reaction vessel, the concentration of the waste material in the oxide phase can be controlled. In addition, the morphology of the oxide phase can be controlled so that once the concentration of the waste material in the oxide phase is adjusted as desired, the waste material can be sequestered within the crystal lattice of the cooled oxide phase for subsequent disposal.

Abstract: The invention relates to the conditioning or packaging of radioactive iodine, particularly iodine 129, using an apatite as the confinement matrix. Having the iodine, said apatite corresponds to the formula:M.sub.10 (XO.sub.4).sub.6-6x (PO.sub.4).sub.6x I.sub.2 (I)in which M represents Cd or Pb, X represents V or As, I is the radioactive iodine to be conditioned and x is such that 0.ltoreq.x<1. This iodoapatite (1) can be surrounded by an apatite (3) not containing iodine serving as a physical barrier.The iodoapatite can be obtained from a solid compound of the iodine, e.g. an iodide such as silver iodide or lead iodide, by reaction with a compound of formula:M.sub.3 (XO.sub.4).sub.2-2x (PO.sub.4).sub.2x (II)orM.sub.10 (XO.sub.4).sub.6-6x (PO.sub.4).sub.6x Y.sub.2 (III)in which M, X and x are as defined hereinbefore and Y can represent OH, F, Cl or O.sub.1/2.

Abstract: Disclosed is a method for converting spent nuclear fuel and surplus plutonium into a vitreous ceramic final waste form wherein spent nuclear fuel is bound in a crystalline matrix which is in turn bound within glass.

Abstract: This invention provides a process wherein hazardous or radioactive wastes in the form of liquids, slurries, or finely divided solids are mixed with finely divided glassformers (silica, alumina, soda, etc.) and injected directly into the plume of a non-transferred arc plasma torch. The extremely high temperatures and heat transfer rates makes it possible to convert the waste-glassformer mixture into a fully vitrified molten glass product in a matter of milliseconds. The molten product may then be collected in a crucible for casting into final wasteform geometry, quenching in water, or further holding time to improve homogeneity and eliminate bubbles.

Abstract: A method for decontaminating of concrete and more specifically to methods used for in-situ thermal desorption of contaminants from concrete, such as PCBs is disclosed. The methods employed heat the concrete at reduced pressure and at a temperature sufficient to volatilize and draw off the contaminant vapors so that the concrete is decontaminated to greater depth than previously obtained, that no concrete waste is created which requires disposal, that the methods produce no secondary liquid waste, that no chemical agents are required, that the decontaminated concrete material can be reused, that the methods are safer for workers because there is no contaminated dust formed during the process and specifically that the process produce a low energy cost per unit area decontamination for the concrete.

Abstract: The invention is the new material, a ternary compound of cesium, silica, and titania, together with a method of making the ternary compound, cesium titanium silicate pollucite. More specifically, the invention is Cs.sub.2 Ti.sub.2 Si.sub.4 O.sub.13 pollucite which is a new crystalline phase representing a novel class of Ti-containing zeolites. Compositions contain relatively high Cs.sub.2 O and TiO.sub.2 loadings and are durable glass and ceramic materials. The amount of TiO.sub.2 and Cs.sub.2 that can be incorporated into these glasses and crystalline ceramics far exceeds the limits set for the borosilicate high level waste glass.

Abstract: A method of atomic scale fixation and immobilization of plutonium to provide a durable waste product. Plutonium is provided in the form of either PuO.sub.2 or Pu(NO.sub.3).sub.4 and is mixed with and SiO.sub.2. The resulting mixture is cold pressed and then heated under pressure to form (Zr,Pu)SiO.sub.4 as the waste product.