Patent application number | Description | Published |
20080247499 | Natural Circulation Boiling Water Reactor And Handling Method Thereof - A handling method for a natural circulation boiling water reactor having a chimney having cylindrical chimney shell disposed above a core in a reactor pressure vessel, a plurality of square tubes disposed in the chimney shell, and a grid support plate with grid holes supporting and in communication with a lower end portion of the square tubes so that adjacent square tubes are disposed at an interval which exceeds the width of one square tube between them. The method includes steps shifting predetermined ones of the square tubes to the interval between the square tubes, and performing maintenance and inspection of members around a core via the grid holes which appear at positions from which the predetermined square tubes are taken out due to the shift of the predetermined square tubes. | 10-09-2008 |
20080292042 | Method of stress corrosion cracking mitigation for nuclear power plant structural materials - The object of this invention is to provide a method for mitigating a stress corrosion cracking of reactor structural material which makes it possible to suppress the rise in the main steam line dose rate without secondary effects such as a rise in the concentration of radioactive cobalt-60, etc. in the reactor water. Hydrogen and a reductive nitrogen compound containing nitrogen having a negative oxidation number (for example, hydrazine) are injected into the core water of boiling water nuclear power plant. By injecting the reductive nitrogen compound containing nitrogen having a negative oxidation number into the core water, the stress corrosion cracking of structural material of reactor can be mitigated without side reactions such as a rise in the concentration of cobalt-60, etc. | 11-27-2008 |
20090003507 | METHOD AND APPARATUS FOR SUPPRESSING CORROSION OF CARBON STEEL, METHOD FOR SUPPRESSING DEPOSIT OF RADIONUCLIDE ONTO CARBON STEEL MEMBERS COMPOSING A NUCLEAR POWER PLANT, AND FILM FORMATION APPARATUS - The present invention is a method for suppressing corrosion of carbon steel members composing a nuclear power plant. That is, the processing solution contains a chemical including iron (II) ions, an oxidizing agent for oxidizing at least one part of the iron (II) ions into iron (III) ion, and a pH adjustment agent for adjusting pH. The pH of the processing solution is adjusted in the range of 5.5 to 9.0 by the pH adjustment agent. The processing solution is introduced into a purifying system pipe having the carbon steel members. The iron (II) ions are adsorbed on an inner surface of the purifying system pipe, namely, a surface of the carbon steel members. The ferrite film is formed on the surface of the carbon steel members by oxidizing the absorbed iron (II) ions. Therefore, corrosion of the carbon steel members is suppressed by the ferrite film. | 01-01-2009 |
20090003508 | Method of suppressing deposition of radioactive isotope - 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. | 01-01-2009 |
20090003509 | Suppression Method of Radionuclide Deposition on Reactor Component of Nuclear Power Plant and Ferrite Film Formation Apparatus - 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. | 01-01-2009 |
20090141849 | Suppression Method of Radionuclide Deposition on Reactor Component of Nuclear Power Plant and Ferrite Film Formation Apparatus - 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. | 06-04-2009 |
20090185653 | Suppression Method of Radionuclide Deposition on Reactor Component of Nuclear Power Plant and Ferrite Film Formation Apparatus - 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. | 07-23-2009 |
20090190712 | METHOD OF STRESS CORROSION CRACKING MITIGATION FOR NUCLEAR POWER PLANT STRUCTURAL MATERIALS - The object of this invention is to provide a method for mitigating a stress corrosion cracking of reactor structural material which makes it possible to suppress the rise in the main steam line dose rate without secondary effects such as a rise in the concentration of radioactive cobalt-60, etc. in the reactor water. Hydrogen and a reductive nitrogen compound containing nitrogen having a negative oxidation number (for example, hydrazine) are injected into the core water of boiling water nuclear power plant. By injecting the reductive nitrogen compound containing nitrogen having a negative oxidation number into the core water, the stress corrosion cracking of structural material of reactor can be mitigated without side reactions such as a rise in the concentration of cobalt-60, etc. | 07-30-2009 |
20090290675 | METHOD AND APPARATUS FOR SUPPRESSING CORROSION OF CARBON STEEL, METHOD FOR SUPPRESSING DEPOSIT OF RADIONUCLIDE ONTO CARBON STEEL MEMBERS COMPOSING A NUCLEAR POWER PLANT, AND FILM FORMATION APPARATUS - The present invention is a method for suppressing corrosion of carbon steel members composing a nuclear power plant. That is, the processing solution contains a chemical including iron (II) ions, an oxidizing agent for oxidizing at least one part of the iron (II) ions into iron (III) ion, and a pH adjustment agent for adjusting pH. The pH of the processing solution is adjusted in the range of 5.5 to 9.0 by the pH adjustment agent. The processing solution is introduced into a purifying system pipe having the carbon steel members. The iron (II) ions are adsorbed on an inner surface of the purifying system pipe, namely, a surface of the carbon steel members. The ferrite film is formed on the surface of the carbon steel members by oxidizing the absorbed iron (II) ions. Therefore, corrosion of the carbon steel members is suppressed by the ferrite film. | 11-26-2009 |
20090316852 | METHOD FOR SUPPRESSING DEPOSIT OF RADIONUCLIDE ONTO STRUCTURE MEMBER COMPOSING NUCLEAR POWER PLANT AND FERRITE FILM FORMATION APPARATUS - A method for suppressing deposit of radionuclide onto structure member composing a nuclear power plant, comprising the steps of:
| 12-24-2009 |
20100136215 | METHOD FOR FORMING FERRITE FILM ONTO SURFACE OF STRUCTURAL MEMBER COMPOSING PLANT, FERRITE FILM FORMATION APPARATUS AND QUARTZ CRYSTAL ELECTRODE APPARATUS - A method for forming a ferrite film onto surface of structural member composing a plant, comprises steps of forming a ferrite film onto the wetted surface of the structural member by making contact with a film forming solution containing iron (II) ions, an oxidant for oxidizing the iron (II) ions, and a pH adjustment agent; measuring the amount of the formed ferrite film; and determining completion of the ferrite film formation based on the measured amount of the formed ferrite film. The method for forming the ferrite film onto the surface of the structural member, can shorten the time required for completing the ferrite film forming operations. | 06-03-2010 |
20110030850 | Suppression Method for Corrosion of Carbon Steel Member - 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. | 02-10-2011 |
20110176649 | Suppression Method of Radionuclide Deposition on Reactor Component of Nuclear Power Plant - 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. | 07-21-2011 |
20110277304 | Method of Forming Ferrite Film on Structural Member Composing Plant - Both ends of a circulation pipe of a film formation apparatus are connected to a piping of a BWR plant. A chemical including chromium ions and formic acid is injected into a film formation solution flowing in the circulation pipe heated to a temperature within a range from 60° C. to 100° C. Furthermore, a chemical including iron (II) ions and formic acid, hydrogen peroxide, and hydrazine are injected into the circulation pipe. Due to the injection of these chemicals, a film formation solution of pH 7.0 including iron (II) ions, chromium ions, formic acid, hydrogen peroxide, and hydrazine is generated in the circulation pipe. This film formation solution includes hydrazine of, for example, 1000 ppm. The film formation solution is supplied to the piping, thus, a Fe | 11-17-2011 |
20120298875 | Radiation Measurement Apparatus and Method of Measuring Radiation - In a radiation measurement apparatus, an analog pulse signal output from a semiconductor radiation detector is converted to a plurality of digital signals by an analog-to-digital converter for each analog pulse signal. A threshold circuit for inputting these digital signals discriminates digital signals exceeding a threshold value. A digital signal integration circuit integrates the plurality of discriminated digital signals for each analog pulse signal and obtains an integrated value for each analog pulse signal. A spectrum generation circuit for inputting the respective integrated values generates a radiation energy spectrum using the integrated values and accurately performs the quantitative analysis and energy analysis of a radioactive nuclide using the radiation energy spectrum. A quantitative analysis and an energy analysis of a radioactive nuclide can be accurately performed while a time resolution of a radiation detector can be maintained. | 11-29-2012 |
20130202791 | Suppression Method for Corrosion of Carbon Steel Member - 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. | 08-08-2013 |