Abstract: Compositions and methods are provided for assessing the presence or absence, and optionally quantitating, the surface loading of a noble metal such as platinum on the surface of a substrate. The invention utilizes the decomposition rate of hydrogen peroxide (H2O2) or other redox active molecule following exposure to the substrate surface to effectively establish a qualitative or quantitative correlation between the redox agent survival fraction and the presence or absence of noble metal (e.g., platinum), and further, for the quantitation of noble metal loading on the substrate surface. The invention finds applicability in assessing the surface loading of noble metals on the internal surfaces of boiling water nuclear reactor plants (BWR) that have undergone prior noble metal application.

Abstract: The present invention provides compositions and methods for assessing the presence or absence, and optionally quantitating, the surface loading of a noble metal such as platinum on the surface of a substrate. The invention utilizes the decomposition rate of hydrogen peroxide (H2O2) or other redox active molecule following exposure to the substrate surface to effectively establish a qualitative or quantitative correlation between the redox agent survival fraction and the presence or absence of noble metal (e.g., platinum), and further, for the quantitation of noble metal loading on the substrate surface. The invention provides advantages over the state of the art, and finds applicability in diverse industries. In some embodiments, the compositions and/or methods of the invention are used to assess the surface loading of noble metals on the internal surfaces of boiling water nuclear reactor plants (BWR) that have undergone prior noble metal application.

Abstract: Provided are methods and systems for generating nanoparticles from an inorganic precursor compound using a hydrothermal process within at least one CSTR or PFR maintained at an elevated temperature and an elevated pressure and a treatment vessel in which this reaction solution can be applied to one or more catalyst substrates. In operation, the reaction solution may be maintained within the CSTR at a substantially constant concentration and within a reaction temperature range for a reaction period sufficient to obtain nanoparticles having a desired average particle size of, for example, less than 10 nm formation and/or deposition. Variations of the basic method and system can provide, for example, the generation of complex particle size distribution profiles, the selective deposition of a multi-modal particle size distribution on a single substrate.

Abstract: A method for operating a nuclear reactor may include adding one or more chemicals to water in the reactor prior to reactor shutdown, during reactor shutdown, or prior to and during reactor shutdown. The one or more chemicals may trigger release of one or more radioactive substances from at least one out-of-core surface of the reactor into the reactor water. A method for reducing post-shutdown radiation levels of a nuclear reactor may include adding one or more chemicals to water in the reactor prior to reactor shutdown, during reactor shutdown, or prior to and during reactor shutdown. The one or more chemicals may include, for example, one or more metals, metal ions, metal compounds, metals and metal ions, metals and metal compounds, metal ions and metal compounds, or metals, metal ions, and metal compounds.

Abstract: A method for mitigating stress corrosion cracking of a component exposed to a high temperature water in a high temperature water system is provided. The method comprises the steps of lowering corrosion potential conditions to a desired low corrosion potential in the high temperature water environment; and introducing a first material comprising zinc into the high temperature water environment, such that the desired low corrosion potential facilitates transport of the first material into cracks in a structure communicative with the high temperature water environment.

Abstract: A method and system for reducing stress corrosion cracking in a hot water system, such as a nuclear reactor, by reducing the electrochemical corrosion potential of components exposed to high temperature water within the structure. The method includes the steps of: providing a reducing species to the high temperature water; and providing a plurality of noble metal nanoparticles having a mean particle size of up to about 100 nm to the high temperature water during operation of the hot water system. The catalytic nanoparticles, which may contain at least one noble metal, form a colloidal suspension in the high temperature water and provide a catalytic surface on which a reducing species reacts with least one oxidizing species present in the high temperature water. The concentration of the oxidizing species is reduced by reaction with the reducing species on the catalytic surface, thereby reducing the electrochemical corrosion potential of the component.

Abstract: A method and system for reducing stress corrosion cracking in a hot water system, such as a nuclear reactor, by reducing the electrochemical corrosion potential of components exposed to high temperature water within the structure. The method comprises the steps of: providing a reducing species to the high temperature water; and providing a plurality of noble metal nanoparticles having a mean particle size of up to about 100 nm to the high temperature water during operation of the hot water system. The catalytic nanoparticles, which may comprise at least one noble metal, form a colloidal suspension in the high temperature water and provide a catalytic surface on which a reducing species reacts with least one oxidizing species present in the high temperature water. The concentration of the oxidizing species is reduced by reaction with the reducing species on the catalytic surface, thereby reducing the electrochemical corrosion potential of the component.

Abstract: A system and method for determining a noble metal concentration in a sample that is representative of a noble metal concentration in either a volume of water circulated through a nuclear reactor or a surface of a nuclear reactor component exposed to the volume of water. The system comprises: at least one standard having a predetermined concentration of the noble metal disposed its surface; an electrolyte bath for immersing one of the sample and the standard therein; an auxiliary electrode connectable to one of the sample and the standard; a power source connectable to a reference electrode and one of the standard and the sample; and a current measurement device capable of measuring a current passing between the auxiliary electrode and one of the sample and the standard.

Abstract: A method for mitigating crack growth on the surface of stainless steel or other metal components in a water-cooled nuclear reactor. A compound containing a noble metal, e.g., palladium, is injected into the water of the reactor in the form of a solution or suspension. This compound has the property that it decomposes under reactor thermal conditions to release ions/atoms of the noble metal which incorporate in or deposit on the interior surfaces of the crack. The compound may be organic, organometallic (e.g., palladium acetylacetonate) or inorganic in nature. The palladium deposited inside a crack should exhibit catalytic behavior even if the bulk surface palladium is depleted under high fluid flow conditions. As a result, the electrochemical potential inside the crack is decreased to a level below the critical potential to protect against intergranular stress corrosion cracking.

Abstract: A method of depositing noble metals on surfaces or matrices to manufacture industrial catalysts that can be used in a variety of applications. Such deposition of noble metals can be achieved by treating the surfaces in high-temperature (150.degree. C. or higher) water containing dissolved noble metal ions or its colloidal suspensions. The method consists of the steps of placing the surface of a metal substrate in contact with a volume filled with high-temperature water; injecting a solution of a noble metal compound into the volume for a predetermined duration; and removing the surface of the metal substrate from contact with the high-temperature water after expiration of said predetermined duration. The noble metal compound has the property that it releases species of the noble metal in high-temperature water. These noble metal species deposit on or incorporate in the oxide film on the surface of the metal substrate.

Abstract: A method for improving the performance and longevity of coatings of metal deposited from aqueous solutions of inorganic, organic or oraganometallic metal compounds. The method involves co-deposition of noble metal or corrosion-inhibiting non-noble metal during growth of oxide film on a component made of alloy, e.g., stainless steels and nickel-based alloys. The result is a metal-doped oxide film having a relatively longer life in the reactor operating environment. In particular, incorporation of palladium into the film provides greatly increased catalytic life as compared to palladium coatings which lie on the oxide surface.

Abstract: A system for ensuring the distribution of noble metal in the reactor circuit during plant application without measuring the reactor water for noble metal content by chemical analysis. The system performs the measurement of electrochemical corrosion potential in an autoclave or a high-flow test section that is connected to the reactor water circuit through sample lines downstream of the injection port, preferably the point in the reactor circuit which is furthest from the injection port. If the noble metal flows into the autoclave or test section at these distant points in the reactor circuit, then the noble metal will deposit on the test specimens inside the autoclave or test section.