Abstract: The invention relates to a method for dissolving an oxide layer containing chromium, iron, nickel, and radionuclides by means of an aqueous oxidative decontamination solution, which contains permanganic acid and a mineral acid and which flows in a circuit (K1), wherein the oxidative decontamination solution is set to a pH value ?2.5.

Abstract: The invention relates to a process for dissolving a chromium, iron, nickel, zinc and radionuclides containing oxide layer, in particular for breaking down oxide layers deposited on inner surfaces of systems and components of a nuclear power plant, by means of an aqueous decontamination solution containing methanesulfonic acid, which flows in a loop, wherein in regular intervals small amounts of permanganic acid are added, and following reaction of the permanganic acid a second loop is added on in bypass and the dissolved cations and anions are removed by ion-exchange resins from the decontamination solution.

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: The invention relates to a method of decontaminating an oxide layer-comprising surface of a component or a system of a nuclear facility, wherein the oxide layer is treated with gaseous nitrogen oxide (NOx) as oxidizing agent.

Abstract: A method of decontaminating an oxide layer-comprising surface of a component or a system of a nuclear facility. An acidic water film is produced on the surface, the film of water is brought into contact with a gaseous acid anhydride, and the oxide layer is treated with gaseous ozone as oxidizing agent.

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 of decontaminating an oxide layer-comprising surface of a component or a system of a nuclear facility. An acidic water film is produced on the surface, the film of water is brought into contact with a gaseous acid anhydride, and the oxide layer is treated with gaseous ozone as oxidizing agent.

Abstract: The invention relates to a method of decontaminating an oxide layer-comprising surface of a component or a system of a nuclear facility, wherein the oxide layer is treated with gaseous nitrogen oxide (NOx) as oxidizing agent.

Abstract: The radioactivity of a metal part is reduced in the process. In the method, firstly a layer of oxide is removed from the metal part using a decontamination solution. Then, an agent which has an oxidizing action and is still present is removed from the decontamination solution. As a result, a layer of the metal is removed. Since radionuclides are to be found only in the layer of the metal part which is close to the surface, the remaining metal can be scrapped in the conventional way.

Abstract: A method for decontaminating a surface includes the steps of bringing a surface of a component formed of an unalloyed steel or a low-alloy steel into contact with a solution containing an oxalic acid for dissolving a contaminated layer from the component. Ions of divalent iron in the solution instantly form a protective layer on exposed surfaces. Iron(III) oxalate is converted into iron(II) oxalate and carbon dioxide by irradiation with UV light in order to provide ions of divalent iron. Subsequent to dissolving the contaminated layer, the protective layer is dissolved by lowering the level of the ions of the divalent iron in the solution. The ions of the divalent iron and the substance having caused the contaminated layer are bound to an ion exchange resin.

Abstract: Nitrate ions are removed from a solution. Such a solution is, in particular, a spent decontamination solution or another spent solution intended for reducing the radioactivity of a metal part. It is provided that the solution, if it comprises a short-chain organic compound, is irradiated with UV light. Otherwise, such a compound is introduced into the solution prior to irradiation. Using the method, the nitrate ions are chemically reduced, forming, for example, N2, N2O, CO2 and H2O.

Abstract: A method for disposing of metal cations includes binding them to a cation exchange resin. The valence of the metal which forms the metal cations is lowered to the lowest possible value. The metal cations, the metal of which has the lowest possible valence, are then bound to the cation exchange resin. The valence of the metal is lowered, for example, by reduction, for which purpose, by way of example, an organic compound together with UV irradiation is used.

Abstract: A method for decontaminating a surface includes the steps of bringing a surface of a component formed of an unalloyed steel or a low-alloy steel into contact with a solution containing an oxalic acid for dissolving a contaminated layer from the component. Ions of divalent iron in the solution instantly form a protective layer on exposed surfaces. Iron(III) oxalate is converted into iron(II) oxalate and carbon dioxide by irradiation with UV light in order to provide ions of divalent iron. Subsequent to dissolving the contaminated layer, the protective layer is dissolved by lowering the level of the ions of the divalent iron in the solution. The ions of the divalent iron and the substance having caused the contaminated layer are bound to an ion exchange resin.

Abstract: A method and a device are provided for disposing of an aqueous solution that contains an organic acid and an iron complex and occurs particularly in the decontamination of radioactively contaminated surfaces of components. It is contemplated that the iron complex in the solution is reduced by irradiation with UV light. A dissolved iron salt and carbon dioxide, which is given off, are formed in the process. An oxidant is then added to the solution that contains the dissolved iron salt and the organic acid. This produces water, and the iron complex forms once again. Some of the dissolved iron salt is removed from the solution by means of a cation exchanger. The solution containing the iron complex is irradiated again with UV light. A cycle process ensues, which continues until all the organic acid is consumed.

Abstract: A cation exchanger is loaded only with radioactive cations by repeatedly converting the non-bivalent, inactive cations into anionic complexes and flushing the complexes out of the cation exchanger. The cation exchanger, which may be integrated in a primary system of a nuclear power plant, is connected to a feed line for a complexing agent and to a discharge line through which the anionic complexes are flushed from the exchanger.

Abstract: A method for chemical decontamination of the surface of a metal component of a nuclear reactor plant includes treating the surface of the metal component in a single-step method with an aqueous solution that is free of carbonic acid oxalic acid and contains a different carbonic acid.

Abstract: Chemical decontamination of large components and systems of metallic materials of nuclear reactors with a liquid reactor coolant, wherein the treatment is carried out by means of an aqueous solution of oxidizing chemicals which is moved through the large components and systems to be decontaminated. Nitrates, chromates or Ce-IV salts are added as oxidizing chemicals in the particularly borate-containing primary coolant and also an addition of ozone is used.

Abstract: Chemical decontamination of metallic parts of nuclear reactor installation in which an oxidative treatment with a permanganic acid solution is applied before dicarbonic acids are used for further treatment. Rinsing operations are eliminated and smaller amounts of dicarbonic acids needed. Also the primary system of the nuclear reactor no longer requires emptying before effecting decontamination treatment.

Abstract: Chemical decontamination of equipment contaminated with radioactive material, such as components and systems, particularly water-cooled nuclear reactors, by pretreating with alkaline permanganate, rinsing with demineralized water, treating with a citrate-oxalate solution, rinsing with demineralized water, and post-treating with an acidified hydrogen peroxide solution containing suspended inert particles. Solutions desirably contain no sulfur. The decontamination solution with a pH of about 3.5 and other preferred operating conditions are recited.