Abstract: There is provided an organic iodine trapping apparatus that can efficiently trap an organic iodine without using complicated or large equipment. An organic iodine trapping apparatus 30 is an apparatus that traps an organic iodine, including: a trapping vessel 1 through which gas containing an organic iodine is passed; an organic iodine remover 2 (Example: trihexyl (tetradecyl) phosphonium chloride, or the like) that is disposed in or injected into the trapping vessel 1 and decomposes the organic iodine; and a trapping material 3 that is disposed in or injected into the trapping vessel 1 and traps iodine ions generated by decomposition of the organic iodine, in which the trapping material 3 is a metal (Example: silver or the like) or a metal compound (Example: silver chloride, silver oxide, or the like).

Abstract: Provided is a chemical decontamination method that shortens the decomposition time of a reduction decontamination agent. An oxidization decontamination, a decomposition of an oxidization decontamination agent, and reduction decontamination using an oxalic acid aqueous solution are performed on a target piping of a BWR plant. After that, the oxalic acid is decomposed (S7). That is, a part of the oxalic acid is decomposed by irradiating the oxalic acid aqueous solution with ultraviolet rays upstream of a decomposition device (S8), and Fe3+ in the aqueous solution is converted to Fe2+. Hydrogen peroxide is supplied to the decomposition device (S9). In the decomposition device, the oxalic acid is decomposed by a catalyst and hydrogen peroxide, Fe2+ and hydrogen peroxide react to produce Fe3+ and OH*, and the oxalic acid is decomposed by OH*. A corrosion potential of the aqueous solution flowing out from the decomposition device is measured (S11).

Abstract: To provide an iodine trapping apparatus capable of trapping organic iodine in a wide temperature range with high efficiency. The iodine trapping apparatus includes a first trapping agent 2 capable of trapping organic iodine in a gas in a nuclear power structure main body. The first trapping agent 2 contains a generating and trapping component which generates an iodide ion (I?) from organic iodine (RI) and traps the generated iodide ion, and a generating component which is different from the generating and trapping component, generates an iodide ion from the organic iodine at least at 100° C. to 130° C., and traps the generated iodide ion in the generating and trapping component.

Abstract: A chemical decontamination method includes a dissolution step in which a radioactive insoluble substance containing a metal oxide, the radioactive insoluble substance being adhered to a decontamination object including carbon steel, is dissolved in a decontamination solution and a metal-ion removal step in which the decontamination solution containing the metal ion, the decontamination solution being produced in the dissolution step, is brought into contact with a cation-exchange resin in order to remove the metal ion, the dissolution step including a reductive dissolution step conducted using a decontamination solution containing formic acid, ascorbic acid and/or erythorbic acid, and a corrosion inhibitor.

Abstract: There is provided an organic iodine trapping apparatus that can efficiently trap an organic iodine without using complicated or large equipment. An organic iodine trapping apparatus 30 is an apparatus that traps an organic iodine, including: a trapping vessel 1 through which gas containing an organic iodine is passed; an organic iodine remover 2 (Example: trihexyl (tetradecyl) phosphonium chloride, or the like) that is disposed in or injected into the trapping vessel 1 and decomposes the organic iodine; and a trapping material 3 that is disposed in or injected into the trapping vessel 1 and traps iodine ions generated by decomposition of the organic iodine, in which the trapping material 3 is a metal (Example: silver or the like) or a metal compound (Example: silver chloride, silver oxide, or the like).

Abstract: To provide a corrosion mitigation method for carbon steel pipe that can further reduce corrosion of the carbon steel pipe. In a BWR plant, oxygen is injected from an oxygen injection device 30 into a clean up system pipe 18 which is constituted by a Cr-containing carbon steel pipe containing Cr in a range of larger than 0.052 wt % and less than 0.4 wt % and being in communication with a RPV 3, and reactor water of 150° C. having a dissolved oxygen concentration of 30 ?g/L is generated. The reactor water is brought into contact with an inner surface of the clean up system pipe 18 to perform an oxidizing treatment on the inner surface, and an oxide film containing Cr is formed on the inner surface.

Abstract: The present disclosure provides a method for relieving a corrosive environment of a boiling water reactor, the method including a step of injecting hydrogen and a noble metal compound into water to be replenished into the reactor pressure vessel during a period of a generating operation of a boiling water nuclear power plant including the reactor pressure vessel. In the method, the hydrogen is injected into water to be supplied into the reactor pressure vessel, and the noble metal compound is injected into water in a line of the boiling water nuclear power plant in which a concentration of oxygen or hydrogen peroxide is stoichiometrically higher than the concentration of hydrogen at which hydrogen undergoes a chemical reaction to turn to water.

Abstract: A chemical decontamination method includes a dissolution step in which a radioactive insoluble substance containing a metal oxide, the radioactive insoluble substance being adhered to a decontamination object including carbon steel, is dissolved in a decontamination solution and a metal-ion removal step in which the decontamination solution containing the metal ion, the decontamination solution being produced in the dissolution step, is brought into contact with a cation-exchange resin in order to remove the metal ion, the dissolution step including a reductive dissolution step conducted using a decontamination solution containing formic acid, ascorbic acid and/or erythorbic acid, and a corrosion inhibitor.

Abstract: An aqueous solution of alkali hexahydroxo platinate is produced. As a alkali hexahydroxo platinate, sodium hexahydroxoplatinate or potassium hexahydroxoplatinate is used. The aqueous solution of alkali hexahydroxo platinate is passed through a hydrogen form cation exchange resin layer in a cation exchange resin tower. The aqueous solution of alkali hexahydroxo platinate makes contact with the hydrogen form cation exchange resin of the hydrogen form cation exchange resin layer, thus a suspension of hexahydroxo platinic is generated. If gamma rays are irradiated to the suspension, a platinum oxide colloidal solution in which colloidal particles including a platinum dioxide, a platinum monoxide, and a platinum hydroxide exist is generated. In a platinum oxide colloidal solution, the content of impurities is little and a noble metal compound is dispersed stably in water.

Abstract: The present disclosure provides a method for relieving a corrosive environment of a boiling water reactor, the method including a step of injecting hydrogen and a noble metal compound into water to be replenished into the reactor pressure vessel during a period of a generating operation of a boiling water nuclear power plant including the reactor pressure vessel. In the method, the hydrogen is injected into water to be supplied into the reactor pressure vessel, and the noble metal compound is injected into water in a line of the boiling water nuclear power plant in which a concentration of oxygen or hydrogen peroxide is stoichiometrically higher than the concentration of hydrogen at which hydrogen undergoes a chemical reaction to turn to water.

Abstract: In an electrodeposition treatment of an iron-group metal ion-containing liquid, without being influenced by the properties of the iron-group metal ion-containing liquid, iron-group metal ions are efficiently removed from the liquid by precipitation. An anode chamber 2A provided with an anode 2 and a cathode chamber 3A provided with a cathode 3 are separated from each other by a cation exchange membrane 5, an iron-group metal ion-containing liquid is charged into the anode chamber 2A, a cathode liquid is charged into the cathode chamber 3A, and by applying the voltage between the anode 2 and the cathode 3, iron-group metal ions in the liquid in the anode chamber 2A are moved into the liquid in the cathode chamber 3A through the cation exchange membrane 5, so that an iron-group metal is precipitated on the cathode 3.

Abstract: There is provided an adhesion restraint method of a radionuclide to a carbon steel material of an atomic energy plant, in which an adhesion restraint effect of the radionuclide to the carbon steel material can continue for a longer term. A film forming apparatus is connected to a carbon steel purification system pipe of a BWR plant. A nickel formate aqueous solution and hydrazine are injected into a circulation pipe of the film forming apparatus. An aqueous solution including nickel formate and hydrazine is guided into a purification system pipe subjected to chemical decontamination, and a nickel metal film is formed on an inner surface of the pipe. A platinum ion aqueous solution and hydrazine are injected into the circulation pipe, and an aqueous solution including a platinum ion and hydrazine is supplied to the purification system pipe so as to adhere platinum to the surface of a nickel metal film. The film forming apparatus is detached from the purification system pipe, and the BWR plant is started.

Abstract: A method in which an anode chamber and a cathode chamber are separated by a cation exchange membrane, an acid solution containing metal ions is introduced into the anode chamber, a cathode solution is introduced into the cathode chamber, and a current is applied across the anode and the cathode, whereby the metal ions in the solution in the anode chamber pass through the cation exchange membrane, move into the cathode solution, and precipitate as metal onto the cathode, wherein there are minimal instances where electrodeposition is impossible or the electrodeposition rate decreases. Pre-adding a salt of the acid contained in the acid solution makes it possible to suppress concentration-diffusion of the acid from the acid solution. Adding a salt of the acid into the cathode chamber makes it possible to reduce the impressed voltage, reduce the amount of hydrogen generated on the cathode, and reduce the amount of power.

Abstract: The present disclosure provides a method for relieving a corrosive environment of a boiling water reactor, the method including a step of injecting hydrogen and a noble metal compound into water to be replenished into the reactor pressure vessel during a period of a generating operation of a boiling water nuclear power plant including the reactor pressure vessel. In the method, the hydrogen is injected into water to be supplied into the reactor pressure vessel, and the noble metal compound is injected into water in a line of the boiling water nuclear power plant in which a concentration of oxygen or hydrogen peroxide is stoichiometrically higher than the concentration of hydrogen at which hydrogen undergoes a chemical reaction to turn to water.

Abstract: An aqueous solution of alkali hexahydroxo platinate is produced. As a alkali hexahydroxo platinate, sodium hexahydroxoplatinate or potassium hexahydroxoplatinate is used. The aqueous solution of alkali hexahydroxo platinate is passed through a hydrogen form cation exchange resin layer in a cation exchange resin tower. The aqueous solution of alkali hexahydroxo platinate makes contact with the hydrogen form cation exchange resin of the hydrogen form cation exchange resin layer, thus a suspension of hexahydroxo platinic is generated. If gamma rays are irradiated to the suspension, a platinum oxide colloidal solution in which colloidal particles including a platinum dioxide, a platinum monoxide, and a platinum hydroxide exist is generated. In a platinum oxide colloidal solution, the content of impurities is little and a noble metal compound is dispersed stably in water.

Abstract: In an electrodeposition treatment of an iron-group metal ion-containing liquid, without being influenced by the properties of the iron-group metal ion-containing liquid, iron-group metal ions are efficiently removed from the liquid by precipitation. An anode chamber 2A provided with an anode 2 and a cathode chamber 3A provided with a cathode 3 are separated from each other by a cation exchange membrane 5, an iron-group metal ion-containing liquid is charged into the anode chamber 2A, a cathode liquid is charged into the cathode chamber 3A, and by applying the voltage between the anode 2 and the cathode 3, iron-group metal ions in the liquid in the anode chamber 2A are moved into the liquid in the cathode chamber 3A through the cation exchange membrane 5, so that an iron-group metal is precipitated on the cathode 3.

Abstract: Disclosed is a method for treating a radioactive organic waste, the radioactive organic waste including a cation exchange resin adsorbing radionuclide ions, the method including the step of bringing the radioactive organic waste into contact with an organic acid salt aqueous solution containing an organic acid salt and whereby desorbing the radionuclide ions from the cation exchange resin, in which the organic acid salt contained in the organic acid salt aqueous solution includes a cation that is more readily adsorbable by the cation exchange resin than hydrogen ion is. This enables reduction in concentration of a radioactive substance in the radioactive organic waste and reduction in amount of a high-dose radioactive waste.

Abstract: A noble metal injection apparatus is connected to a piping of a nuclear plant at the time of stop of the nuclear plant before start of the nuclear plant. In chemical decontamination, oxidation decontamination agent decomposition, and reduction decontamination on an inner surface of the pipe system are executed. After reduction decontamination, a part of an oxalic acid included in a reduction decontamination solution is decomposed and platinum is injected into the reduction decontamination solution of pH 3.5 or higher. When the platinum concentration becomes a preset concentration, a reduction agent is injected and the reduction decontamination solution including the platinum and reduction agent is brought into contact with the inner surface of the piping. The platinum is deposited on the inner surface of the piping. The injection of the platinum and reduction agent is stopped and the platinum and reduction agent are decomposed.

Abstract: A circulation pipe of a chemical decontamination apparatus including a malonic acid injection apparatus and an oxalic acid injection apparatus is connected to a purification system pipe, which is made of carbon steel, of a boiling water nuclear power plant. A malonic acid aqueous solution is injected from the malonic acid injection apparatus into the circulation pipe. An oxalic acid aqueous solution is injected from the oxalic acid injection apparatus into the circulation pipe. A reduction decontaminating solution including a malonic acid of 5200 ppm and an oxalic acid within a range of 50 to 400 ppm is supplied into the purification system pipe through the circulation pipe. Reduction decontamination for an inner surface of the purification system pipe is executed. After the reduction decontamination for the purification system pipe finishes, the malonic acid and oxalic acid included in the solution are decomposed and furthermore, the solution is purified.

Abstract: A circulation pipe of a chemical decontamination apparatus including a malonic acid injection apparatus and an oxalic acid injection apparatus is connected to a purification system pipe, which is made of carbon steel, of a boiling water nuclear power plant. A malonic acid aqueous solution is injected from the malonic acid injection apparatus into the circulation pipe. An oxalic acid aqueous solution is injected from the oxalic acid injection apparatus into the circulation pipe. A reduction decontaminating solution including a malonic acid of 5200 ppm and an oxalic acid within a range of 50 to 400 ppm is supplied into the purification system pipe through the circulation pipe. Reduction decontamination for an inner surface of the purification system pipe is executed. After the reduction decontamination for the purification system pipe finishes, the malonic acid and oxalic acid included in the solution are decomposed and furthermore, the solution is purified.