Systems and methods for steam generator tube analysis for detection of tube degradation

Abstract

The systems and methods of the invention pertain to analyzing steam generator tube data for the detection of wear. Further, the invention is capable of performing a comparison of current tube signal data to baseline or historic tube signal data, e.g., from previous and/or the first, in-service inspection of the steam generator. The systems and methods are automated and can generate results to show potential tube-to-tube contact wear areas as well as the progression of tube-to-tube gap reduction within a steam generator tube bundle. In certain embodiments, the invention is capable of comparing current and historical eddy current data to determine the difference that may be related to degradation or other interested phenomena, and of processing and trending historical comparison results to establish normal variance and detect abnormal variances.

1 .- 8 . (canceled) 
     
     
         9 . A method of employing at least one eddy current sensor and at least one digital computing device to non-destructively assess a current condition of a number of tubes of a steam generator of a nuclear power plant, the method comprising:
 collecting at a first time with a digital computing device and using an eddy current sensor received in and advanced through each of at least some of the number of tubes a historic data set for each of at least some of the number of tubes;   collecting at a second time with a digital computing device and using an eddy current sensor received in each of at least some of the number of tubes and advanced there through a current data set for each of at least some of the number of tubes;   measuring noise window of the historical data set to determine a historical noise baseline;   storing the historical noise baseline in the digital computing device;   measuring noise window of the current data set to determine a current noise baseline;   storing the current noise baseline in the digital computing device;   comparing the historical noise baseline and the current noise baseline to determine a difference; and   identifying a region of a baseline shift based on the difference to show potential tube to tube contact or long taper wear.   
     
     
         10 . A method of employing at least one eddy current sensor and at least one digital computing device to non-destructively assess a current condition of a number of tubes of a steam generator of a nuclear power plant, the method comprising:
 collecting at a first time with a digital computing device and using an eddy current sensor received in and advanced through each of at least some of the number of tubes a historic data set for each of at least some of the number of tubes;   collecting at a second time with a digital computing device and using an eddy current sensor received in each of at least some of the number of tubes and advanced there through a current data set for each of at least some of the number of tubes;   measuring a signal of interest using the historical data set and recording at least one signal characteristic selected from the group consisting of signal amplitude, phase, pattern, signal width, and signal area;   storing the at least one signal characteristic in database;   measuring a signal of interest using the current data set and recording at least one signal characteristic selected from the group consisting of signal amplitude, phase, pattern, signal width, and signal area;   storing the at least one signal characteristic in database;   generating a trending plot comparison between the at least one signal characteristic for the historical and current data sets to determine variances there between;   determining a normal variances based on the historical data set to determine a normal variance zone; and   determining an abnormal variance based on the current data set if the comparison is different than the normal variance.   
     
     
         11 . The method of  claim 9 , wherein the at least one eddy current sensor and the at least one digital computing device assess bobbin coil eddy current data for the historic data set and the current data set. 
     
     
         12 . The method of  claim 9 , wherein the collecting each of the historic data set and the current data set includes performing a total signal and noise analysis employing a real time automated analysis computer code. 
     
     
         13 . The method of  claim 9 , wherein the measuring of the noise window of the historical data set and the current data set includes identifying tube U-bends, tube supports and transitions. 
     
     
         14 . The method of  claim 9 , wherein the measuring of the noise window of the historical data set and the current data set includes identifying straight length tube sections. 
     
     
         15 . The method of  claim 10 , further comprising transforming the historic and current data sets for amplitude and phase adjustment for differences in inspection tester configuration and tester excitation modes. 
     
     
         16 . The method of  claim 10 , further comprising storing the trending curve and slope in a database, and establishing the slope and standard deviation of normal variance for each in-service inspection. 
     
     
         17 . The method of  claim 10 , further comprising querying the database to detect sudden slope change with current and prior data comparison and mapping the query results to a tube sheet map to highlight regions of concern. 
     
     
         18 . A method of analyzing steam generator bobbin coil data for detection of tube-to-tube contact wear and tube-to-tube proximity, comprising:
 a. performing a baseline total signal and noise analysis;   b. performing a baseline signal analysis of interfering structures, wherein the interfering structures comprise tube U-bends, tube supports and transitions;   c. performing a baseline signal analysis of straight line tube sections;   d. removing the baseline signal analysis of interfering structures from the baseline total signal and noise analysis for creating a true measurement of a baseline signal analysis;   e. storing the true measurement of the baseline signal analysis in a database as historical data;   f. repeating steps a. through e. for a current inspection to produce current data;   g. comparing the historical data and the current data; and   h. identifying changes between the historical data and the current data,   wherein, changes in the straight length tube sections signals indicate a potential tube proximity issue, and   wherein changes in the tube u-bends, tube supports and transitions signals indicate a potential wear issue.   
     
     
         9 . A method of employing at least one eddy current sensor and at least one digital computing device to non-destructively assess a current condition of a number of tubes of a steam generator of a nuclear power plant, the method comprising:
 collecting at a first time with a digital computing device and using an eddy current sensor received in and advanced through each of at least some of the number of tubes a historic data set for each of at least some of the number of tubes;   collecting at a second time with a digital computing device and using an eddy current sensor received in each of at least some of the number of tubes and advanced there through a current data set for each of at least some of the number of tubes;   measuring noise window of the historical data set to determine a historical noise baseline;   storing the historical noise baseline in the digital computing device;   measuring noise window of the current data set to determine a current noise baseline;   storing the current noise baseline in the digital computing device;   comparing the historical noise baseline and the current noise baseline to determine a difference; and   identifying a region of a baseline shift based on the difference to show potential tube to tube contact or long taper wear.   
     
     
         10 . A method of employing at least one eddy current sensor and at least one digital computing device to non-destructively assess a current condition of a number of tubes of a steam generator of a nuclear power plant, the method comprising:
 collecting at a first time with a digital computing device and using an eddy current sensor received in and advanced through each of at least some of the number of tubes a historic data set for each of at least some of the number of tubes;   collecting at a second time with a digital computing device and using an eddy current sensor received in each of at least some of the number of tubes and advanced there through a current data set for each of at least some of the number of tubes;