Abstract: Heavy metals are removed from waste lubricating oil by heating in the presence of an oxidation catalyst and a free radical initiator at temperatures in the range of about 150.degree.-200.degree. C. Corrosion and oxidation inhibitors previously added to the oil are thereby oxidized to form a separable sludge which contains the bulk of heavy metal contamination. The process is of particular advantage in removing contaminating radioactive nuclides from lubricating oils used in nuclear generating facilities.

Abstract: The present invention relates to a process for nuclear waste disposal. In it, a glass forming mixture including an aqueous solution of one or more metal alkoxides, alcohol, and solubilized, low level radioactive waste having a pH effective to hydrolyze the one or more metal alkoxides is formed. The one or more metal alkoxides in the glass forming mixture are converted to a network of corresponding one or more metal oxides. A gel is then formed from the glass forming mixture containing the network of one or more metal oxides. The gel is dried and sintered under conditions effective to form a densified glass.

Abstract: A processing system for radioactive waste is composed of an adjusting tank having a sampling port, a solidification processing system, and a package inspection apparatus, and a package, of which inventory per a package has been exactly grasped, is prepared by solidification of the waste with the processing system after determining radioactivity of the waste by measurement before the solidifying process.In accordance with the present invention, data on radioactivity before and after preparation of package of waste become clear, and management of each package at transportation and intermediate storage of the packages is facilitated.

Abstract: An adsorbent useful for the adsorption of radioactive nuclides which comprises fibrous active carbon having a specific surface area of 1,000 m.sup.2 /g or more and an equilibrium moisture regain of 10% or more at a relative humidity of 45%; and a process for the volume-reduction treatment of radioactive liquid waste which comprises subjecting radioactive liquid waste containing radioactive nuclides to an adsorption treatment using an adsorbent comprising fibrous active carbon having a specific surface area of 1,000 m.sup.2 /g or more, and subsequently subjecting the spent adsorbent to an incineration treatment at a temperature which is equal to or higher than the ignition point of the fibrous active carbon.

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: The extraction process includes supplying solvent under gas pressure for introduction of the solvent adjacent the bottom of a vessel containing the sample. The vessel lies in a water bath and ultrasonic energy is applied to the bath and hence to the sample to facilitate interaction between the solvent and the sample. Because the solvent is immiscible in the sample and of lesser density, the solvent and solubilized material rise to the top of the vessel. An extraction tube under vacuum pressure continuously removes the solvent with the solubilized material.

Abstract: A method of adsorbing and separating a heavy metal element by using a tannin adsorbent comprising:(a) adjusting the pH of a solution containing a plurality of heavy metal elements to a predetermined pH;(b) contacting the adsorbent with the solution in which the pH thereof is adjusted;(c) adjusting the pH of the solution contacted with the adsorbent to a pH different from the predetermined pH; and(d) contacting the solution in which the pH thereof is adjusted at the step (d) with the adsorbent prepared at the step (a).According to the inventive method, all of the heavy metal elements can be efficiently separated and adsorbed by using a tannin adsorbent from a solution containing a number of heavy metal elements. A method of regenerating a tannin adsorbent are also disclosed.

Abstract: The present invention relates to a method for separating chemical contaminants such as volatile and semi-volatile chemicals and polychlorinated biphenyls (PCBs), even if the contaminants are present at low concentrations, from mixed wastes, such as soils or sludges contaminated with hazardous and radioactive components. The process comprises subjecting the mixed waste to vacuum at a temperature effective to volatilize the contaminants but below incineration temperature, while continuously removing the evolved vapors, for a period of time sufficient to effect the desired degree of separation of the volatile and semi-volatile contaminants. The evolved vapors may be collected and condensed for off-site disposal and the remaining solids may be properly disposed of or further treated.

Abstract: A process for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO.sub.2 to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO.sub.2, noble metal compounds, nitrates, formates and so forth.

Abstract: A process for the decontamination of solid surfaces contaminated with radioactive or heavy metal species using a solution based on one or more non-persistent complexing agents, or for the chemical cleaning of steam generator sludge using such a solution, or for removing radioactive or heavy metal species from a solution using a combination of a one or more non-persistent complexing agents and a solid support, followed in each case by thermal or thermal-chemical treatment to decompose said non-persistent complexing agent. The preferred non-persistent complexing agents are hydroxamic acids, and the most preferred is acetohydroxamic acid.

Abstract: Processes and devices are disclosed for converting an aqueous waste solution, such as a radioactive waste stream, into a highly concentrated sludge having substantially little or no water. In turn, the sludge may be converted into a solid polymeric form suitable for storage. The processes utilize a carrier liquid which has a boiling point higher than that of water, and which facilitates the transfer of heat to the water to vaporize the water into steam. A subsequent separation of the dewatered solution yields the highly concentrated sludge.

Abstract: A method for regenerating a spent solvent generated from a nuclear fuel cycle and containing a higher hydrocarbon (n-dodecane), tributyl phosphate and degradation products thereof. The spent solvent is brought into contact with a methanol/water mixture having a water concentration of 100 to 750 g/l and the resulting mixture is subjected to phase separation to form a non-methanol/water phase and a methanol/water phase. The degradation products such as DBP in the spent solvent selectively migrate into the methanol/water phase and n-dodecane and TBP can be recovered as the non-methanol/water phase.

Abstract: A process for handling liquid radioactive waste includes evaporating liquid radioactive waste with condensation of vapors; refilling the waste during the evaporation; and measuring a condensate quantity and controlling the refilling with the measure of the condensate quantity. A device for handling liquid radioactive waste includes a device for evaporating liquid radioactive waste with condensation of vapors; a device for refilling the waste during the evaporation; a measuring vessel for collecting condensate; a valve for controlled drainage of the condensate from the measuring vessel; and a device connected to the valve for determining the condensate quantity removed from said measuring vessel. The device for determining the condensate quantity removed controls the refilling of the waste in accordance with the condensate quantity removed.

Abstract: Treatment of flowable underground contaminants comprises freezing at least one open underground barrier volume to form a wall (10) near the contaminated region (12) in the ground (14), where the wall (10) is positioned to direct the contaminant flow (16) along a subsurface path (18) and allow concentration of the contaminants and their remediation.

Abstract: Remediation of soil, concrete and groundwater using electropotential gradient induced migration of a target ion and immobilization and/or confinement of the target ion by a host receptor matrix (HRM). In addition to immobilizing and/or confining the target ion, the HRM can comprise a buffer or an ionizable species which releases an exchange ion during application of the electropotential gradient. The exchange ion, when less mobile than a (H.sup.+) ion or hydroxyl (OH.sup.-) ion, increases the efficiency of energy usage during decontamination. The exchange ion can also perform other tasks in the vicinity of the electrodes which improve the decontamination process. The host receptor matrix can comprise a material which is water impermeable and which has a low surface energy, such as a layer of polytetrafluoroethylene film. When such a material is used, the host receptor matrix can comprise a receptacle in which there is a liquid and/or solid composition.

Abstract: A submergible torch for removing nitrate and/or nitrite ions from a waste solution containing nitrate and/or nitrite ions comprises: a torch tip, a fuel delivery mechanism, a fuel flow control mechanism, a catalyst, and a combustion chamber. The submergible torch is ignited to form a flame within the combustion chamber of the submergible torch. The torch is submerged in a waste solution containing nitrate and/or nitrite ions in such a manner that the flame is in contact with the waste solution and the catalyst and is maintained submerged for a period of time sufficient to decompose the nitrate and/or nitrite ions present in the waste solution.

Abstract: Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.