Abstract: A method for separating boric acid from a liquid, especially liquid waste obtained from a nuclear power plant. In the method, the waste solution containing the boric acid is contacted with steam in a reactor so that the boric acid evaporates from the liquid and passes into the steam vapor phase. Consequently, the radioactive wastes which are not evaporated with the steam remain in the waste water while the boric acid is removed from the waste water when it passes into the vapor or steam phase. The boric acid can then be separated and recovered from the steam by means of a distillation and fractionating column or a wash column. By removing the boric acid from the liquid waste, it is possible to obtain concentrated radioactive waste having a reduced volume due to the absence of boric acid in the waste.

Abstract: A process for in-drum drying of liquid radioactive waste includes sealing a shielded container by placing a plug in a central opening formed in a lid of the container. The plug is removed from the opening and a filling adapter having an outside diameter that fits the opening is inserted into the opening. Liquid radioactive waste is poured into the sealed container and vapors are vented from the container, through the filling adapter. The liquid radioactive waste is heated in the container with a heater. A filling adapter for in-drum drying of liquid radioactive waste includes a rectilinear, preferably cylindrical steel casing with end regions, an outer periphery, a flange protruding past the outer periphery at one of the end regions, at least two connection points at another of the end regions, and a filling line extending from one of the connection points through the steel casing.

Abstract: The present invention provides a method for separating boric acid from a liquid, especially liquid waste obtained from a nuclear power plant. In the process, the waste solution containing the boric acid is contacted with steam in a reactor so that the boric acid evaporates from the liquid and passes into the steam vapor phase. Consequently, the radioactive wastes which are not evaporated with the steam remain in the waste water while the boric acid is removed from the waste water when it passes into the vapor or steam phase. The boric acid can then be separated and recovered from the steam by means of a distillation and fractionating column or a wash column. By removing the boric acid from the liquid waste, it is possible to obtain concentrated radioactive waste having a reduced volume due to the absence of boric acid in the waste.

Abstract: A process for in-drum drying of liquid radioactive waste includes sealing a shielded container by placing a plug in a central opening formed in a lid of the container. The plug is removed from the opening and a filling adapter having an outside diameter that fits the opening is inserted into the opening. To measure the fill level a sensor is inserted into the filling adapter and protrudes from a free end of the filling adapter into the interior of the container. Liquid radioactive waste is poured into the sealed container and vapors are vented from the container, through the filling adapter. The liquid radioactive waste is heated in the container with a heater.

Abstract: A method of treatment of a high-level radioactive waste comprising heating the radioactive waste at a high temperature of about 500.degree. to 3000.degree. C. to vaporize part of the elements contained in the radioactive waste, and cooling the resultant vapor to separately collect the elements. In one embodiment, the heating step is replaced by a reduction-heating step wherein heating is carried out in the presence of a reducing agent, e.g. hydrogen. In another embodiment, the heating step may be followed by the reduction-heating step.

Abstract: A process for the treatment of waste water containing boron compounds and radionuclides. The waste water is essentially vaporized until dry to yield a concentrate. Boric acid ester and an azeotropic mixture of water and alcohol are produced in a reaction by the addition of an excess of a long chain primary alcohol, e.g. butyl alcohol, to the concentrate. The azeotropic mixture, excess alcohol and boric acid ester are then separated from the concentrate by distilling. The non-radioactive components are then separated from the concentrate leaving behind a radioactive residue, which can be safely disposed of. The azeotropic mixture is then separated back into water and alcohol, and the boric acid ester is saponified back into boric acid and alcohol. The alcohol and boric acid are recycled back into the treatment process and to the nuclear reactor.

Abstract: The present invention relates to a technique of concentrating waste water whereby the water content of the waste water is removed with a high decontamination factor, employs a porous membrane having a property allowing gas such as steam to permeate but not allowing a liquid such as water to do, as a membrane for concentrating the waste water, and adopts a method wherein the waste water is turned into a vapor flow and this vapor flow is made to contact the porous membrane so as for the waste water to be concentrated on the occasion when the waste water is to be concentrated by means of this porous membrane. By turning the waste water into the vapor flow, most of various metal ions, a surfactant, etc. existing in the waste water are separated from the vapor flow. Mist, metal ions in the mist and others contained in the vapor flow are removed by the aforesaid porous membrane from the steam while permeating the same.

Abstract: A method of and apparatus for the treatment and storage of nuclear power plant wastes utilizes a jacket heating a cast iron storage container directly to vaporize liquid radioactive waste under suction applied to the container with interposition of a baffle preventing entrainment of droplets from the container.

Abstract: The present invention provides drying and pulverization of a radioactive liquid waste containing sodium borate as a main component by heating, where the liquid waste is heated, dried and pulverized to substantially crystalline, homogeneous powder of sodium borate while suppressing occurrence of a foaming phenomenon of the powder. The susbtantially crystalline powder is obtained by heating, drying and pulverizing the liquid waste at a temperature outside the temperature range where the salt powder takes an amorphous state in the course of releasing water of crystallization from the salt powder. In the drying and pulverization of a liquid waste containing sodium borate by a thin film evaporator, occurrence of the foaming phenomenon can be suppressed by maintaining the temperature on the heat transfer surface of the evaporator at a temperature lower than 150.degree. C.

Abstract: Reducing the volume of radioactively loaded liquids, particularly evaporator concentrates, by heating in a storage container up to solidification, wherein liquids are replenished for filling up the storage container. Heating takes place discontinuously in heating periods separated from each other in time. The heat is introduced directly into the container contents. Vapors produced are drawn off intermittently.

Abstract: A method for thermal decomposition treatment of a radioactive waste uses an apparatus comprising a container for holding molten matter of a radioactive waste containing a sodium compound, a pair of electrodes contacting the molten matter, and a power source for applying voltage between the electrodes while changing the polarity thereof every several tens of seconds. In this apparatus, the molten matter can be heated in the container by Joule heat, which is evolved by electric current directly flowed through the molten matter, so that the sodium compound contained in the radioactive waste can be decomposed, vaporized and removed to recover a stabilized radioactive solid as a residue in the container.

Abstract: A solidifying agent comprising slag dust from the refining of metals, silicates, water-soluble, high molecular weight compounds, metal salts of an organic acid and calcium carbonate. The solidifying agent is useful for solidifying liquid organic halogenides into solid composites containing organic halogenides. The organic halogenides are disposed of by a burning method which comprises converting the organic halogenides to vapors and disposing the organic halogenides by burning the vapors.

Abstract: The pH of low level radioactive waste liquid is adjusted to be substantially neutral and the liquid is passed to apparatus comprising an atomizer (11) having a turbine (15), air being heated by an electric heater (16) to the atomizer (11) to provide low level radioactive waste particles which may be encapsulated, e.g. in a resin. The apparatus may be transportable, and is claimed per se.

Abstract: For bonding particularly radioactive wastes into a binder, a transporting and mixing device is used which transports the mixture to a storage tank prior to the hardening. The wastes are transported into the mixing zone by gravity and aided by the conveyor helix which also imparts additional wall cleaning action through the dry conveyor zone. A single or multi-component binder is concurrently transported in a direction lateral to the mixing tool to the mixing zone. The mixture is conducted in a straight-line extension of the transport and mixing direction to an outlet to which the storage tank is connected.

Abstract: Dry, compactable radioactive waste material having a low specific activity and comprised approximately of eighty-five percent plastic material and fifteen percent non-plastic material is shredded and granulated. The granulated material is supplied under heat and pressure to an extruder which will extrude the waste material in plasticized form into a drum for disposal. Radioactive ion exchange resin beads may also be dewatered and mixed in predetermined amounts with the dry granulated material for encapsulation within the plasticized waste for disposal. The plasticized waste material, with or without the resin, is horizontally extruded into a horizontally disposed drum between a compacting disk secured to the extruder barrel and the bottom of the drum. Controlled pressure is applied against the bottom of the drum whereby the plasticized material will completely fill the space between the disk and the bottom of the drum and gradually push the drum bottom away from the sik as the drum is filled.

Abstract: A volume-reducing solidification treatment method for radioactive waste liquid containing boron primarily in the form of boric acid or borates is disclosed.After an alkali is added to the waste water to adjust pH thereof, and optionally after evaporation concentration is carried out, soluble calcium compounds such as Ca(OH).sub.2 are added, the waste water is stirred at a specific temperature to form insoluble calcium borate aged at a lower temperature than that of forming borate, and evaporation and concentration is carried out, which raises the concentration of the solid component. The concentrated liquid obtained is solidified with cement.The concentrated liquid may also be dried into a powder using a thin film evaporator.

Abstract: The pH of low level radioactive waste liquid is adjusted to be substantially neutral and the liquid is passed to apparatus comprising an atomizer (11) having a turbine (15), air being heated by an electric heater (16) to the atomizer (11) to provide low level radioactive waste particles which may be encapsulated, e.g. in a resin.

Abstract: Ion exchange resin wastes are prepared for disposal by dewatering and/or dehydrating the resins, sealing the pores and recovering the ion exchange resins having radioactive waste products trapped within the sealed pores.

Abstract: Radioactive organic wastes, such as granular or powdered ion exchange resins and organic filter aids, are treated by oxidation decomposition using hydrogen peroxide in the presence of iron ions in an aqueous medium under refluxing an effluent which is condensed from evaporated components during the oxidation. Condensed water containing a very small amount of organic matter is obtained.

Abstract: An apparatus is disclosed for producing a vitric solid solution comprising mainly the solid content of a radioactive waste solution of sodium borate discharged from a pressurized water reactor, the apparatus comprising a waste solution feed tank equipped with a hopper for stabilizing agent in water, a thin film evaporator, a heating type dehydrator, a powder drier connected with a microwave generator through a microwave guide tube and equipped with a stirrer, and a melting furnace connected with a microwave generator through a microwave guide tube, the above units being combined by pipes or a powder-transferring means.

Abstract: A method of batchwise oxidatively reducing radioactive wastes mainly composed of various combustible or poorly combustible organic compounds or the mixtures thereof and containing a small amount of inorganic substances. The oxidative decomposition is carried out in an aqueous solution containing a fusion-preventive agent and a catalyst. The process allows radioactive waste to be oxidatively decomposed effectively and safely while requiring low amounts of energy thereby permitting the volume of the final wastes to be discharged and stored after the oxidative decomposition to be minimized.

Abstract: Water-containing bibulous solids such as ion-exchange or filter matters from a nuclear electricity-generating power plant are introduced into a final storage container and heated therein under vacuum to dewater the solids and provide a high interstitial volume. The latter is substantially filled with radioactive salts by introducing flowable evaporator concentrate in one or more stages and for each stage heating the container under vacuum so as to drive off the concentrate water.

Abstract: Radioactive wastes are treated in a furnace which has electrodes for electric heating. The furnace has at the lower end an outlet for slag material as well as a gas discharge line. Its well is a self-supporting tubular body which is arranged detachably in a metal furnace housing. At the upper end of the well is a line for feeding water. Thereby, carbon-containing waste, possibly also carbon of a carbon bed, is reacted to form water gas (CO+H.sub.2), which is burned after purification in an exhaust gas plant. The outlet of the metal housing has a movable grate.

Abstract: A method of processing radioactive waste resin by pyrolyzing radioactive waste ion exchange resin generated in a nuclear plant such as a nuclear power station. First, the ion exchange resin is pyrolyzed at a low temperature, and the resulting decomposition gas is separated. Second, the ion exchange resin at a high temperature, and the resulting decomposition gas is separated. Finally, the residue of the ion exchange resin is hot-pressed into a molded article.

Abstract: A process is described for reducing the volume of a liquid waste containing an organic amine chelating agent in which a finely atomized spray of the liquid waste is contacted with a gas stream having a temperature in excess of the thermal decomposition temperature of the chelating agent. The proportions of the hot gas stream and liquid waste are controlled to rapidly evaporate water from the liquid waste and cool the gas to a temperature below the decomposition temperature of the chelating agent in a time of less than about 6 seconds to produce a dry, flowable powder product including the chelating agent.

Abstract: A method for processing spent radioactive ion exchange resin formed in a nuclear power plant by a two-step pyrolysis method. First, the spent resin is heated at 350.degree. C. to decompose functional groups selectively. Then the base polymer, formed as residue, is decomposed at a temperature above 350.degree. C., e.g. 600.degree. C. After the thermal decomposition, exhaust gases which require a special exhaust gas disposal means, such as NO.sub.x and SO.sub.x can be reduce to below 1/20.

Abstract: In an installation comprising a solvent regeneration circuit and a solvent recovery circuit, each solvent container is connected independently to the boiler of a distillation unit for cleaning purposes. The relative arrangement of the solvent containers is such that the solvent circulates under the action of gravity from a condenser to the boiler and from each container to the boiler. The boiler is removable for subsequent disposal after filling with solvent residues and waste materials.

Abstract: A method of treating a liquid containing radioactive contaminants to produce a vapor containing a reduced amount of radioactive contaminant wherein continuous evaporation is effected in a vessel comprising two interconnected sections, one surrounding the other, the degree of evaporation in the inner section being greater than in the outer section thereof resulting in a greater concentration of radioactive material in the inner section.The outer evaporation section acts as a shield to reduce the release of radiation from the concentration of radioactive materials in the inner section.

Abstract: The volume of low-level radioactive wastes containing free water is reduced by introducing the waste as a finely atomized spray into a zone heated by means of a hot gas. Contact of the spray particles with the hot gas results in the production of a dry, flowable radioactive solid product and a gaseous non-radioactive product which contains substantially no NO.sub.x or SO.sub.x and no volatile radionuclides, which are retained in the solid product.

Abstract: A radioactive waste is treated by supplying a liquid concentrate of at least one of a radioactive liquid waste and a radioactive waste slurry to a centrifugal film dryer, thereby drying and pulverizing insoluble and soluble solid matters contained in the concentrate, washing the centrifugal film drier with hot water after the drying and pulverization, settling the effluent washing water together with a condensate containing solid matters generated in the drying and pulverization, and supplying a slurry of insoluble solid matters separated by the settling to the centrifugal film drier, thereby drying and pulverizing the solid matters. The dried powder from the centrifugal film drier can be pelletized in a pelletizer, and effluent washing water generated by washing the pelletizer with hot water after the pelletization can be subjected to the settling together with the effluent washing water and the condensate from the centrifugal film drier.

Abstract: An apparatus for continuously concentrating and denitrating a radioactive nitrate solution by microwave includes a rotatably supported concentrating and denitrating vessel disposed within an oven into which microwave is applied through waveguides. The concentrating and denitrating vessel comprises a circular vessel body supported rotatably about its center and a plurality of partition plates positioned radially inside the vessel body so as to divide the interior of the vessel body into a plurality of compartments. The nitrate solution supplied into the vessel is heated, evaporated, concentrated and denitrated in sequence in each of the compartments during one rotation of the vessel to form a denitrated oxide powder. The denitrated powder produced in one of the compartments is transferred into a receiving pan positioned adjacent to the outer periphery of the vessel.

Abstract: Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means.

Abstract: In a treatment system of radioactive waste solution including sodium sulfate generated from a boiling water type nuclear reactor, waste solution is fed into a thin film evaporator where the waste solution is evaporated and made into powder while precipitating in a peripheral surface of the evaporator vessel. The surface of the precipitated solid is wiped by rotating wiper blades and removed off as radioactive solid powder. The rotational speed of a rotor to which the wiper blades are secured is controlled at a minimum and necessary rotational speed which contributes to make the waste solution into the powder so that the rate of worn out of the wiper blade is decreased.

Abstract: The invention relates to a process for the treatment of basic aqueous effluents containing plutonium and possibly uranium.According to this process, the effluents are concentrated by evaporation under reduced pressure, at a temperature such that plutonium precipitation is substantially avoided. Advantageously, the effluents are evaporated at a temperature of 50.degree. to 80.degree. C. for a time such that a concentration factor of at least 6 is obtained.Application to the treatment of aqueous effluents obtained by the alkaline washing of organic solvents used in installations for the reprocessing of irradiated nuclear fuels.

Abstract: Radioactive waste water containing boric acid is concentrated in an evaporator to which an alkali is added to maintain a substantially neutral pH. The boric acid is sedimented out by cooling the solution and an acid is added to the latter to increase the solids recovery by lowering the pH. The solid sediment is vacuum distilled to yield a moist powder.

Abstract: A scraping blade for use in a thin film dryer adapted for processing radioactive substances comprises a main body, a hing member rigidly attached to one side of the body and pivotably connected to a rotor in the dryer, a blade chip attached to the other side of the body for engaging the radioactive substance, and a screw member engaged with the body to secure the blade chip to the body. The blade chip is made of a material more than 1.2 times harder than the radioactive substance. The blade may further comprise an engaging member for screw engagement with the screw having edge portions to be engaged with recesses formed on the blade chip and the main body.

Abstract: An apparatus for the volume reduction of radioactive liquid waste solutions such as evaporator waste bottoms containing boric acid or sodium sulfate and trace quantities of radioactivity through a vacuum evaporative cooling crystallization process or an evaporative crystallization process. A crystallization unit has an internal baffle which separates the center portion of the unit into a quiescent zone where crystallization can be effected and an inner chamber into which the liquid waste is tangentially introduced. The waste is circulated from the bottom of the crystallization unit through a heat exchanger which adjusts the temperature of the liquid waste and maintains the temperature within a predetermined range. The vacuum draws off a portion of the solvent in the solution. Upon the crystallization of the liquid waste solution to a degree which renders a solid-liquid slurry, the slurry is removed from the apparatus for further treatment.

Abstract: Liquid wastes from atomic power plants are treated in an apparatus comprising a low electroconductivity liquid waste concentrator for evaporating a low electroconductivity liquid waste with outside steam as a heat source, and another liquid waste concentrator for evaporating another liquid waste with steam generated by evaporation of the low electroconductivity liquid waste in the low electroconductivity liquid waste concentrator as a heat source.

Abstract: A process and apparatus for solidifying radioactive waste liquid containing dissolved and/or suspended solids is disclosed. The process includes chemically treating for pH adjustement and precipitation of solids, concentrating solids with a thin-film evaporator to provide liquid concentrate containing about 50% solids, and drying the concentrate with heated mixing apparatus. The heated mixing apparatus includes a heated wall and working means for shearing dried concentrate from internal surfaces and subdividing dry concentrate into dry, powdery particles. The working means includes a rotor and helical means for positively advancing the concentrate and resulting dry particles from inlet to outlet of the mixing apparatus. The dry particles may also be encapsulated in a matrix material. Entrained particles in the vapor stream from the evaporator and mixer are removed in an integral particle separator and the vapor is subsequently condensed and may be recycled upstream of the thin-film evaporator.

Abstract: In the concentration of radioactive combustible waste comprising evaporating and drying a radioactive combustible waste slurry by a thin film drier, the radioactive combustible wastes and an incombustible material, such as sodium sulfate, etc. obtained from a nuclear reactor effluent are mixed together in an amount of not more than 70% by weight, preferably 43 to 70% by weight, of radioactive combustible waste on the basis of a mixture on dry basis, and the mixture is fed to the thin film drier and evaporated and dried therein. A risk of powder explosion and fire is prevented in the drying step thereby.

Abstract: A method and apparatus for removing waste products from solutions of fission products, especially nitric solutions, which contain ruthenium. The method utilizes concentration and solidification, especially vitrification, with the solution being concentrated to a solid content of at least about 15 to 20% in a vacuum at a pressure of at most about 50 mm Hg. The apparatus includes a vacuum evaporator, a subsequent mixing device which is fed by nitrate decomposing agents and vitrifiers, and a vitrifying oven. A drying device may be interposed between the mixing device and the oven. Preferably an ammonia derivative, especially urea, is added to the concentrate before solidification.

Abstract: Apparatus for evaporating radioactive liquid and calcinating the residue wherein the radioactive liquid is sprayed across the interior of a casing on to the heated, external surface of a hollow drum so that the droplets evaporate and partially calcinate as they cross the casing interior and then adhere to the drum for a sufficient period to be calcinated thereon. A scraper scrapes the calcinated residue from the drum.

Abstract: Drying radioactive waste water concentrates from evaporators to produce a dried product of low residual moisture by(a) preheating a waste water concentrate with a solids content of at most 20% by weight to a temperature of 50.degree.-70.degree. C.,(b) passing the preheated concentrate with a solids content of at most 20% by weight into a two-cylinder drier at the rate of 10 to 20 liters per square meter of usable cylinder surface per hour,(c) maintaining the cylinder temperature between about 160.degree. to 210.degree. C.,(d) retaining the concentrate in the drier for a residence time of 7 to 18 seconds on the cylinder to produce a dried product of low residual moisture on the cylinder surface, and(e) discharging the dried product of low residual moisture from the cylinder surface.

Abstract: A method of and an apparatus for removing radionuclides from a radioactively contaminated liquid, especially water from the sump of a nuclear electric-power generating plant, in which the waste water is evaporated to produce a vapor phase containing radionuclides in the form of liquid or solid aerosol-dispersed particles which are collected by passing the vapor through an electric field. Preferably a plurality of such fields are traversed in succession by the aerosol.

Abstract: An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

Abstract: Recovering fission material from solid raw wastes and producing a space-saving product which can be committed to ultimate storage by the following steps:(a) a comminution of the raw wastes to a grain size of about 5 mm(b) dissolution thereof at elevated temperature in an organic solvent until a concentration of about 10 percent by weight is reached(c) separation of insoluble raw waste particles larger than 1 mm.(d) separation of the undissolved fission material content remaining in the polymer solution by means of a centrifuge(e) evaporation and condensation of the solvents for return into the dissolving process according to (b)(f) embedding the waste component from (c) into the remaining plastic melt(g) drawing-off the melt and solidification thereof in storage containers.

Abstract: A method and apparatus for reconditioning waste solutions of the nuclear ustry which contain ammonium nitrate. The waste solution is continuously sprayed from above into a 300.degree. to 600.degree. C. hot zone, from the lower end of which the decomposition products are withdrawn and are separated into condensate and exhaust gas. The NO content is reduced by adding oxygen, especially at the exit of the decomposition zone. By the presence of reducing agents, such as CO(NH.sub.2).sub.2 or preferably NH.sub.3, in the solution to be sprayed, the NO.sub.2 content of the decomposition products and the NH.sub.4 NO.sub.3 residue in the condensate can be practically eliminated and an additional precipitation in the condensate which can be filtered off can be obtained. Optimal contents are 0.25-0.4 Mol NH.sub.3 and 0.15-0.25 Mol CO(NH.sub.2).sub.2 per Mol NH.sub.4 NO.sub.3.

Abstract: Apparatus and methods are disclosed for removing concentrated radioactive aqueous waste from an evaporator and delivering the waste to a storage tank. The evaporator drain conduits are maintained full of feed liquor when concentrated waste is not being removed from the evaporator and feed liquor is used to rinse the conduits after the concentrated waste removal through the conduits is completed. The liquid fed through the conduits is carefully controlled by a sequencer or timer. A fast acting evaporator drain valve is used which can be rinsed by feed liquor to avoid plugging and deposition of radioactive solids in the valve.

Abstract: A pump for a radioactive waste concentrator in a shielded enclosure is mounted on a wheeled vehicle that travels on tracks, and a spare pump is mounted on an identical wheeled vehicle outside of the shielded enclosure, adjacent the tracks. If the pump fails, it is wheeled out of the shielded enclosure, and the vehicle carrying the spare pump is put on the tracks and wheeled into the enclosure for quick connection to the concentrator.

Abstract: An inert carrier process for drying radioactive waste material and for incorporating the dry material into a binder from which the dried material will not be leached is disclosed. In this process, a hot inert liquid carrier is provided into which the solution to be dried is introduced under extremely turbulent conditions. The solvent flashes off leaving the dried particles dispersed in the inert carrier which carries these particles to a mixing station where a binder for the particles is injected under turbulent conditions. The binder preferentially wets the particles and the coated particles are carried to a separator section where the binder coated particles coalesce and separate from the carrier as a second phase. Thereafter a curing agent can be added to the binder.