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 method is disclosed for treating liquid radioactive waste to provide reusable water, while reducing the overall volume and water content of the removed solid contaminants. The process is carried out in two separate stages, generally in at least two separate locations. In the first stage, the waste is pretreated at a first site, preferably where the waste was generated, to provide clean water, and a concentrated fraction containing removed suspended and dissolved solids, as well as some remaining water. The pretreatment typically involves passing the liquid waste through one or more microfilters, ultrafilter or nanofilters in combination with a reverse osmosis membrane. In the second stage of the process, the concentrated waste fraction, containing the removed solids, is transported to a second site, where it is thermally treated to remove the remaining water and reduce the volume of the remaining solids.

Abstract: A practical method is described for preparation of radioactive ion-exchange resin for its disposal after the ion-exchange resin has become radioactive in the process of decontaminating radioactive water. Substantially nonradioactive material, which has been derived from the radioactive ion-exchange resin can be disposed of conventionally. The concentration allows corollary reduction of the volume of radioactive waste which must be handled in very costly ways. The radioactive ion-exchange resin and materials that react with the radioactive decaying atoms are heated under controlled atmospheres to (i) form nonvolatile chemicals that hold the decaying atoms, and (ii) under controlled conditions, depolymerize, vaporize, pyrolize, and otherwise decompose and remove nonradioactive components of the ion-exchange resin from the radioactive decaying atoms.

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 treating radioactive waste in the form of contaminated powdery ionic exchange resin to make it suitable for final storage by reducing its volume as much as possible, includes mechanically dewatering the ion exchange resin. The dewatered ion exchange resin is mixed with a calcium compound. The mixture is dried at temperatures of up to 120.degree. C. and preferably about 50.degree. C. to 60.degree. C., and at a pressure of from 120 to 200 hPa, until a residual moisture content of less than 10% of the mass of the mixture is reached. The dry mixture is thermally treated at a pressure below atmospheric pressure by heating up to a temperature of from at least 120.degree. C. to at most 190.degree. C. The ion exchange resin thereby loses its water absorption and swelling capability. Ion exchange resins treated in this manner are processed with cement or bitumen to form blocks that are suitable for final storage.

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 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: Where a concrete structure (12) has been contaminated with tritium (whether as gas or as water) the tritium atoms take the place of ordinary hydrogen atoms in water and in hydroxyl groups in the concrete, rendering it radioactive. The degree of contamination may be reduced by irradiating the surface with microwaves to vaporize water, while extracting water vapor from the surface region through a dust filter (28) and a water trap (30). This can considerably reduce the radioactivity, and hence the cost of disposal of the concrete.