On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers
Integrity monitoring and flaw diagnostics of flat beams and tubular structures was investigated in this research task using guided acoustic signals. A piezo-sensor suite was deployed to activate and collect Lamb wave signals that propagate along metallic specimens. The dispersion curves of Lamb waves along plate and tubular structures are generated through numerical analysis. Several advanced techniques were explored to extract representative features from acoustic time series. Among them, the Hilbert-Huang transform (HHT) is a recently developed technique for the analysis of non-linear and transient signals. A moving window method was introduced to generate the local peak characters from acoustic time series, and a zooming window technique was developed to localize the structural flaws. The time-frequency analysis and pattern recognition techniques were combined for classifying structural defects in brass tubes. Several types of flaws in brass tubes were tested, both in the air and in water. The techniques also proved to be effective under background/process noise. A detailed theoretical analysis of Lamb wave propagation was performed and simulations were carried out using the finite element software system ABAQUS. This analytical study confirmed the behavior of the acoustic signals acquired from the experimental studies. The report presents the background the analysis of acoustic signals acquired from piezo-electric transducers for structural defect monitoring. A comparison of the use of time-frequency techniques, including the Hilbert-Huang transform, is presented. The report presents the theoretical study of Lamb wave propagation in flat beams and tubular structures, and the need for mode separation in order to effectively perform defect diagnosis. The results of an extensive experimental study of detection, location, and isolation of structural defects in flat aluminum beams and brass tubes are presented. The results of this research show the feasibility of on-line monitoring of small structural flaws by the use of transient and nonlinear acoustic signal analysis, and its implementation by the proper design of a piezo-electric transducer suite.
- Research Organization:
- University of Tennessee, Knoxville (US)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy, Science and Technology (NE) (US)
- DOE Contract Number:
- FG07-01ID14114
- OSTI ID:
- 832721
- Report Number(s):
- DE-FG07-01ID14114/UTNE-08; TRN: US0406686
- Resource Relation:
- Other Information: PBD: 27 Sep 2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
22 GENERAL STUDIES OF NUCLEAR REACTORS
ACOUSTICS
ALUMINIUM
BRASS
DEFECTS
DETECTION
DIAGNOSIS
HEAT EXCHANGERS
IMPLEMENTATION
MONITORING
NUMERICAL ANALYSIS
PATTERN RECOGNITION
STEAM GENERATORS
TRANSDUCERS
TRANSIENTS
WATER
WAVE PROPAGATION
STEAM GENERATOR
HEAT EXCHANGER
MONITORING AND DIAGNOSIS
DATA-BASED MODELING
HYBRID MODELING
GROUP METHOD OF DATA HANDLING
HEAT EXCHAGER FOULING
ACOUSTIC SIGNAL ANALYSIS
FAULT DETECTION, ISOLATION, AND LOCATION
HILBERT-HUANG TRANSFORM.