Method and apparatus for maintaining proper noble metal loading for a noble metal application process for water-cooled nuclear reactors

A method for modeling noble metal loading occurring within a water flow circuit for a nuclear reactor during a noble metal deposition process, comprising the steps performed by a computer of:

• a) dividing the water flow circuit into a plurality of separate regions each comprising a plurality of cells of equal flow residence time;
• b) determining noble metal concentrations and surface loadings in each cell using chemical kinetic equations based on local reaction rate constants for each cell;
• and
• c) updating one or more values used for local reaction rate constants based on sampled noble metal concentrations obtained from said selected locations within the water flow circuit.

A method of maintaining proper noble metal loading within a primary water flow circuit for a nuclear reactor for performing a noble metal deposition process, comprising the steps of:

• a) obtaining data representing the initial state of the reactor water chemistry and initial operating conditions of the reactor;
• b) using a computer to model noble metal loading throughout the primary water flow circuit, wherein noble metal loading reactions are modeled by dividing the primary water circuit into a plurality of separate regions each comprising a plurality of cells of equal flow residence time and performing a mass balance evaluation for each individual cell;
• c) sampling the reactor water at one or more selected locations throughout the water flow circuit and measuring concentrations of noble metals for each sample;
• d) comparing measured concentrations of noble metals from each sample with concentration values produced by the computer modeling in step (b);
• e) calibrating a computer model used in computing noble metal reactions by altering values of reaction rate constants used by the computer model until the model results agree with the samples;
• and
• f) altering the operating conditions of the reactor if subsequent loading rates determined by the computer model are inconsistent with predetermined target goals.

A method for controlling the amount of noble metal atoms deposited over time into an oxide layer present on a metal surface of an object in contact with a high temperature fluid containing a compound having said metal atoms, which metal atoms increase the corrosion resistance of said metal surface when present in the oxide film, said method comprising the steps of:

• a) using a computer to model noble metal loading in the fluid;
• b) sampling the fluid at one or more selected times during deposition and measuring concentrations of noble metals at each sample time;
• d) comparing measured concentrations of noble metals from at least one sample with concentration values computed by the computer model;
• e) calibrating the computer model by altering values of reaction rate constants used by the computer model until the model results agree with the sampled concentrations;
• and
• f) altering temperature conditions and/or noble metal concentrations in the fluid if subsequent loading rates determined by the computer model are inconsistent with predetermined deposition goals.