Abstract: A method for conditioning of spent ion exchange resins from nuclear facilities comprises the steps of: mixing the spent ion exchange resins with water to form a reaction mixture; setting and controlling the pH of the reaction mixture in a range from 1.0 to 3.5, preferably in a range from 2.0 to 3.0; adding an oxidant to the reaction mixture, with the temperature of the reaction mixture maintained at 90 ° ° C. or less so that the spent ion exchange resin and the oxidant react with each other to form an aqueous reaction solution comprising the organic reaction products of the spent ion exchange resin; and electrochemically oxidizing the organic reaction products, wherein carbon dioxide is produced and a carbon-depleted aqueous reaction solution having a TOC (total organic carbon) value of less than 50 ppm is obtained. Furthermore, an apparatus for the conditioning of spent ion exchange resins from nuclear facilities is described.

Abstract: A process removes radioactive contamination from wastewater obtained in the decontamination of a cooling circuit of nuclear reactors or of parts thereof or in the course of operation of a nuclear reactor. A MnO2 precipitate is exclusively produced in the wastewater with the aid of permanganate ions added thereto as an oxidizing agent and of one or more organic reducing agents present in and/or metered into the wastewater, and the MnO2 precipitate is separated from the wastewater.

Abstract: A process removes radioactive contamination from wastewater obtained in the decontamination of a cooling circuit of nuclear reactors or of parts thereof or in the course of operation of a nuclear reactor. A MnO2 precipitate is exclusively produced in the wastewater with the aid of permanganate ions added thereto as an oxidizing agent and of one or more organic reducing agents present in and/or metered into the wastewater, and the MnO2 precipitate is separated from the wastewater.

Abstract: A method for decontaminating nuclear plant surfaces, which have been contaminated with alpha emitters, is carried out subsequently to a decontamination process which is aimed at the removal of oxide layers. The surfaces are treated with an aqueous solution which contains a cationic or zwitterionic surfactant and oxalic acid. At least a part of the solution, after having acted on a surface, is conducted across an ion exchanger.

Abstract: A method for chemical decontamination of an oxide-coated surface of a metal structural part or of a system in a nuclear power plant with several cleaning cycles, involves oxidation steps, in which the oxide layer is treated with an aqueous solution containing an oxidation agent, and a subsequent decontamination step, in which the oxide layer is treated with an aqueous solution of an acid. At least one oxidation step is carried out in an acid solution and at least one oxidation step in an alkaline solution.

Abstract: A process is provided for chemically decontaminating the surface of a metallic component. In a first treatment step, an oxide layer formed on the component by corrosion of the material of the component is detached from the surface of the component with a first aqueous treatment solution containing an organic decontamination acid. In a subsequent second treatment step, the surface which is at least partially freed of the oxide layer is treated with an aqueous solution containing an active component for removing particles which adhere to the surface. The active component is formed of at least one anionic surfactant from the group including sulphonic acids, phosphonic acids, carboxylic acids and salts of those acids.

Abstract: A method chemically decontaminates a surface of a metal component of a primary circuit of a pressurized-water reactor, the surface contains an oxide layer. In a first stage, an oxidation step, a reduction step, and a first decontamination step are performed. The component is treated in the oxidation step with an aqueous solution containing an oxidizing agent, which converts trivalent chrome present in the oxide layer into hexavalent chrome. The component is treated in the reduction step with an aqueous solution containing a reducing agent for reducing excess oxidation agent from the oxidation step. The component is treated in the first decontamination step with an aqueous solution containing a decontamination acid that forms no antisoluble deposits with metal ions in the solution. The solution is fed through an ion exchanger for removing metal ions. In a second stage, the component is treated with an aqueous solution containing an oxalic acid.

Abstract: A process is provided for chemically decontaminating the surface of a metallic component. In a first treatment step, an oxide layer formed on the component by corrosion of the material of the component is detached from the surface of the component with a first aqueous treatment solution containing an organic decontamination acid. In a subsequent second treatment step, the surface which is at least partially freed of the oxide layer is treated with an aqueous solution containing an active component for removing particles which adhere to the surface. The active component is formed of at least one anionic surfactant from the group including sulphonic acids, phosphonic acids, carboxylic acids and salts of those acids.

Abstract: A method for decontaminating nuclear plant surfaces, which have been contaminated with alpha emitters, is carried out subsequently to a decontamination process which is aimed at the removal of oxide layers. The surfaces are treated with an aqueous solution which contains a cationic or zwitterionic surfactant and oxalic acid. At least a part of the solution, after having acted on a surface, is conducted across an ion exchanger.