Eddy Current Tube Support Plate Blockage Detection
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Solution Overview
Problem
Current methods for assessing tube support plate (TSP) blockage in steam generators are inefficient, relying on extensive visual examinations that are time-consuming and expose personnel to radiation, and do not effectively relate deposition patterns to critical operational parameters, leading to uncertainties in steam generator performance.
Innovation Solution
A method using bobbin eddy current measurements to quantify deposition at TSP flow regions, combined with a blockage calibration and thermal/hydraulic model to determine the impact on steam generator operational parameters, such as pressure losses and water level control, through a virtual calibration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual examination methods are used to assess TSP blockage, then personnel can directly observe deposition patterns, but the examination process is time-consuming and exposes personnel to radiation
Solution Approach 1:
The patent replaces the mechanical visual examination system with an eddy current detection system. The eddy current probe measures electrical impedance changes caused by deposition, converting a visual/mechanical inspection process into an electrical measurement process that is faster and safer
Solution Approach 2:
The patent introduces eddy current measurements as an intermediary between the deposition and the assessment process. Instead of directly observing deposition, the system measures eddy current signals that are affected by deposition, providing indirect but quantifiable data about blockage
2Loss of information
If visual examination methods are used to assess TSP blockage, then deposition patterns can be observed, but there is no effective relationship established between deposition patterns and critical operational parameters
Solution Approach 1:
The patent establishes a feedback loop where eddy current measurements are converted to deposition thickness, which is then input to thermal-hydraulic models that predict operational parameters. This creates a quantitative relationship between deposition and system performance
Solution Approach 2:
The patent transforms qualitative visual deposition patterns into quantitative parameters (eddy current impedance values, calculated deposition thickness) that can be mathematically related to operational parameters through calibration and modeling
3Reliability
If extensive visual examination is performed to reduce uncertainties in steam generator performance, then more complete data on TSP flow regions can be obtained, but the time and radiation exposure requirements become unacceptable
Solution Approach 1:
The patent replaces extensive manual visual examination with automated eddy current scanning, dramatically increasing examination speed and efficiency while maintaining or improving assessment reliability through quantitative measurements
Solution Approach 2:
The patent creates an electrical signal copy of the physical deposition state through eddy current measurements. This electrical representation can be analyzed without requiring physical access or exposure to radiation, preserving information while eliminating hazards
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
Enables accurate assessment of TSP blockage and its effects on steam generator performance, reducing uncertainties and improving operational reliability by providing measurable values for risk assessment and performance analysis.
Implementation Method 1
measuring a population of eddy current values with an eddy current probe
Implementation Method 2
changes in the electrical impedance of the eddy current probe
Data Source
AI summary
A method for determining tube support plate blockage of a steam generator includes the following steps: measuring at least five different eddy current values per tube support intersection; calculating a nominal clean fit radius of flow hole; determining a center signal response; converting the center signal response to a deposit thickness; determine an edge reduction; converting the edge reduction to an edge thickness; calculating the resulting flow hole radius; verifying the reasonableness of the resulting flow hole radius; and determining a virtual calibration range.