Abstract: More accurate prediction of reactor water quality of a nuclear reactor is implemented. A device for prediction of reactor water quality of a nuclear reactor in a nuclear power plant is disclosed. The device stores a reactor water quality prediction model which is learned using learning data, and with which future reactor water quality is predicted. An explanatory variable of the reactor water quality prediction model includes a value in a predetermined period unit that is generated from data acquired in an operating nuclear power plant. The device generates the value in a predetermined period unit from data acquired in a target operating nuclear power plant, and acquires a predicted value of the reactor water quality in the target nuclear power plant based on the reactor water quality prediction model and the value in a predetermined period unit.

Abstract: According to one embodiment, a liquid crystal display device includes a first area, second area, liquid crystal layer, and a plurality of pixels. Each subpixel includes an opening area including a first opening area and a second opening area. The pixels include a first pixel positioned in the first area and a second pixel positioned over a boundary of the first area and the second area. The opening area of the second pixel is smaller than the opening area of the first pixel when opening areas of subpixels of same color are compared. An each imaginary line showing the boundary of the first opening area and the second opening area is a same straight line.

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: A film-forming apparatus is connected to a carbon steel cleanup system pipe of a BWR plant. Formic acid and hydrogen peroxide are injected into the circulation pipe of the film-forming apparatus. An iron elution accelerator aqueous solution containing 3000 ppm of formic acid and 1500 ppm of hydrogen peroxide is brought into contact with the inner surface of the cleanup system pipe, and Fe2+ is eluted from the cleanup system pipe by formic acid, and hydroxyl radicals generated from hydrogen peroxide. The film-forming aqueous solution produced from the iron elution accelerator aqueous solution by injecting the nickel formate aqueous solution is brought into contact with the inner surface of the cleanup system pipe, and the Ni ions incorporated into the inner surface by the substitution reaction are reduced by the electrons generated at the time of elution of Fe2+ to form a Ni metal film on the inner surface thereof.

Abstract: A reactor water radioactivity concentration of a nuclear power plant can be predicted with high accuracy. First, a plant state quantity prediction value is calculated by using a physical model that describes plant state quantities of the power plant including a flow rate of feedwater and a metal corrosion product concentration in feedwater of the reactor water is calculated. Next, data for supervised learning is created, and the data for supervised learning includes the previously calculated plant state quantity prediction value and a plant state quantity such as the flow rate of feedwater, the metal corrosion product concentration in feedwater, a metal corrosion product concentration in reactor water, and a radioactive metal corrosion concentration of the reactor water in the reactor as input data and includes a radioactive metal corrosion concentration in the reactor water which is an actual measured value as output data, and a predictive model is trained.

Abstract: A chemical decontamination method capable of improving the decontamination efficiency of chemical decontamination of a steam dryer in the RPV is provided. In particular, the decontamination method includes feeding a chemical decontamination aqueous solution into a reactor pressure vessel in which a steam dryer is arranged, and after chemical decontamination of the steam dryer, the water level of the chemical decontamination aqueous solution existing in the reactor pressure vessel is lowered to a first water level below the lower end of the steam dryer.

Abstract: Provided are a chemical decontamination method and a chemical decontamination apparatus capable of preventing deterioration of a metal ion exchange resin and performing decontamination at a low cost in a short time. The chemical decontamination method of the invention includes: a reduction decontamination step of supplying a reduction decontamination solution to a decontamination target portion and performing reduction decontamination on a surface of a member constituting the decontamination target portion; a hydrogen peroxide decomposition step of decomposing hydrogen peroxide contained in the reduction decontamination solution after the reduction decontamination step; and a metal ion removing step of removing a metal ion contained in the reduction decontamination solution after the hydrogen peroxide decomposition step.

Abstract: More accurate prediction of reactor water quality of a nuclear reactor is implemented. A device for prediction of reactor water quality of a nuclear reactor in a nuclear power plant is disclosed. The device stores a reactor water quality prediction model which is learned using learning data, and with which future reactor water quality is predicted. An explanatory variable of the reactor water quality prediction model includes a value in a predetermined period unit that is generated from data acquired in an operating nuclear power plant. The device generates the value in a predetermined period unit from data acquired in a target operating nuclear power plant, and acquires a predicted value of the reactor water quality in the target nuclear power plant based on the reactor water quality prediction model and the value in a predetermined period unit.

Abstract: A reactor water radioactivity concentration of a nuclear power plant can be predicted with high accuracy. First, a plant state quantity prediction value is calculated by using a physical model that describes plant state quantities of the power plant including a flow rate of feedwater and a metal corrosion product concentration in feedwater of the reactor water is calculated. Next, data for supervised learning is created, and the data for supervised learning includes the previously calculated plant state quantity prediction value and a plant state quantity such as the flow rate of feedwater, the metal corrosion product concentration in feedwater, a metal corrosion product concentration in reactor water, and a radioactive metal corrosion concentration of the reactor water in the reactor as input data and includes a radioactive metal corrosion concentration in the reactor water which is an actual measured value as output data, and a predictive model is trained.

Abstract: A film forming apparatus is connected to a carbon steel purification system piping of a BWR plant (S1). Formic acid (surface purification agent) is injected into a circulation piping of the film forming apparatus (S4). A surface purification agent aqueous solution containing 30000 ppm of formic acid is contacted with the inner surface of the purification system piping, and a large amount of Fe2+ is dissolved from the purification system piping, and a large amount of electrons are generated by this dissolution. Thereafter, a formic acid Ni aqueous solution is injected into the surface purification agent aqueous solution to produce a film forming aqueous solution (S5). The film forming aqueous solution storing the electrons is contacted with the inner surface of the purification system piping, and Ni ions incorporated into the inner surface are reduced by the electrons, and a Ni metal film is formed on the inner surface.

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 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.

Abstract: A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to a feed water pipe made of carbon steel in a BWR plant. This solution is supplied into the pipe through the circulation pipe, and a nickel metal film is formed on an inner surface of the pipe. After the film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the pipe. The nickel ferrite film comes into contact with water containing dissolved oxygen at or above 150° C. to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe.

Abstract: A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to feed water pipe made of carbon steel in a BWR plant. This film-forming aqueous solution is supplied into the feed water pipe through the circulation pipe, and then, a nickel metal film is formed on an inner surface of the feed water pipe. After the nickel metal film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the feed water pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the feed water pipe. Then, the nickel ferrite film is come into contact with water containing dissolved-oxygen at 150° C. or above to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe. Corrosion of the carbon steel member composing the plant can further reduce.

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 formic acid aqueous solution that contains Fe (II) ions is produced by dissolving metal iron in a formic acid aqueous solution. Nitrogen is supplied from a nitrogen supply device to a chemical liquid tank and then discharged from a discharge line to reduce the dissolved oxygen concentration in the aqueous solution. The chemical liquid tank is filled with the formic acid aqueous solution sealed with nitrogen, and is transferred from a factory to a nuclear reactor building designated as radiation-controlled areas. Inside the nuclear reactor building, the chemical liquid tank is installed in a film deposition apparatus connected to a reactor water recirculation pipeline. The formic acid aqueous is supplied from the chemical liquid tank to the inside of the reactor water recirculation pipeline, and then a ferrite film is formed on the inner surface of the reactor water recirculation pipeline.

Abstract: A method of suppressing deposition of radionuclides on components of a nuclear power plant comprises forming a ferrite film by contacting a first chemical including iron (II) ions, a second chemical for oxidizing the iron (II) ions to iron (III) ions, and a third chemical for adjusting the pH of a processing solution containing a mixture of the first and second chemicals to be 5.5 to 9.0 with the metal member surface in a time period from a finishing stage in decontamination step of removing contaminants formed on the surface of metal member composing the nuclear power plant, and suppressing deposition of radionuclides on the metal member by the ferrite film.