Noble Metal Loading Analysis via Hydrogen Peroxide Decomposition
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Solution Overview
Problem
Current methods for assessing and quantitating noble metal loading on the internal surfaces of boiling water nuclear reactor plants are labor-intensive, destructive, and require expensive instrumentation, making it challenging to accurately determine low platinum loadings and potentially leading to errors and delays in inspection relief.
Innovation Solution
A method utilizing the decomposition of a redox active molecule, such as hydrogen peroxide, to correlate with platinum loading by measuring the survival fraction, which is non-destructive and can be conducted on-site, eliminating the need for aqua regia digestion and ICPMS analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional destructive methods (aqua regia digestion and ICPMS analysis) are used to assess noble metal loading, then measurement precision can be achieved, but the process becomes labor-intensive, time-consuming, and requires expensive instrumentation
Solution Approach 1:
The patent replaces the mechanical/chemical destruction process (aqua regia digestion) and expensive ICPMS instrumentation with an electrochemical measurement system that uses polarization curves and Tafel extrapolation to determine noble metal loading through electrochemical corrosion potential and current density measurements
Solution Approach 2:
The patent employs a simpler, more accessible electrochemical measurement approach that does not require expensive ICPMS instrumentation, using standard electrochemical cells and power supplies that are widely available and cost-effective
2Measurement precision
If traditional destructive sampling is performed, then accurate platinum loading quantitation can be obtained, but the process causes delays in inspection relief and requires sample destruction
Solution Approach 1:
The patent replaces destructive chemical digestion with non-destructive electrochemical measurements that can be performed in-situ, allowing the reactor components to remain intact and available for immediate inspection relief without waiting for lengthy digestion and analysis processes
3Measurement precision
If ICPMS instrumentation is used for analysis, then detection capability for low platinum loadings is improved, but the cost and complexity of the system increases significantly
Solution Approach 1:
The patent substitutes complex ICPMS instrumentation with a simpler electrochemical measurement system that uses polarization curves and Tafel extrapolation methodology to achieve sensitive detection of low platinum loadings through electrochemical potential and current measurements
Solution Approach 2:
The patent creates an indirect measurement approach where instead of directly measuring platinum concentration with complex instrumentation, it measures the electrochemical response (corrosion potential and current density) that correlates with platinum loading, providing a functional copy of the information
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for rapid, reliable, and accurate assessment of noble metal loading, reducing the need for destructive sampling and expensive instrumentation, facilitating inspection relief and improving the efficiency of noble metal application monitoring.
Implementation Method 1
The presence of noble metals deposited onto reactor internal surfaces can reduce the internal surface susceptibility to stress corrosion cracking... OLNC uses the electrocatalytic effect of platinum to efficiently recombine O2 and H2O2 with H2 on the metal surface
Implementation Method 2
These methods utilize the decomposition of a redox active molecule, for example but not limited to hydrogen peroxide (H2O2), to effectively establish a correlation between the survival fraction of the redox reagent following exposure to the substrate surface
Implementation Method 3
Typical NMCA applications (injection of noble metals into the reactor water) are performed just prior to an outage at a temperature of 240 to 290° F. (116 to 148° C.)... achieve low electrochemical corrosion potentials (ECP)
Data Source
AI summary
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.