Patent application number | Description | Published |
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 |
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 |
20100206729 | ELECTROCHEMICAL CORROSION POTENTIAL SENSOR - An electrochemical corrosion potential sensor (ECP sensor) has an electrode cap, an electrode fixing body, a tubular insulator, a tubular metallic housing, and a conductive wire. Both ends of the tubular insulator are connected to the electrode fixing body and the tubular metallic housing respectively. A conductive wire passes through the tubular insulator and the tubular metallic housing, and is connected to an inner surface of the electrode fixing body. The electrode cap | 08-19-2010 |
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 |
20110268242 | Hydrogen and Oxygen Recombination Catalyst, Recombination Apparatus, and Nuclear Plant - A recombination apparatus is provided to an off-gas system of a boiling water nuclear plant. An off-gas system pipe connected to a condenser is connected to the recombination apparatus. A catalyst layer filled with a catalyst for recombining hydrogen and oxygen is disposed in the recombination apparatus. The recombination catalyst has a percentage of the number of Pt particles whose diameters are in a range from more than 1 nm to not more than 3 nm to the numbers of Pt particles whose diameters are in a range from more than 0 nm to not more than 20 nm, falling within a range from 20 to 100%. The condenser discharges gas containing an organosilicon compound (ex. D5), hydrogen, and oxygen, which is introduced to the recombination apparatus. Use of the above recombination catalyst can improve the performance of recombining hydrogen and oxygen more than conventional catalysts and the initial performance of the catalyst can be maintained for a longer period of time. | 11-03-2011 |
20150073198 | Method of Chemical Decontamination for Carbon Steel Member of Nuclear Power Plant - 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. | 03-12-2015 |