Comparison of an Array of EMATs Technique and a Magnetostrictive Sensor Technique for a Guided Wave Inspection of a Pipe

2006 ◽  
Vol 321-323 ◽  
pp. 780-783 ◽  
Author(s):  
Yong Moo Cheong ◽  
Hyun Kyu Jung ◽  
Young Suk Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Ultrasonic Method ◽  
Wave Structure ◽  
Guided Wave ◽  
Point Of View ◽  
Torsional Mode ◽  
Ultrasonic Methods ◽  
Sensor Technique ◽  
Magnetostrictive Sensor

The leakage of a pipe in nuclear power plants is a significant concern from the point of view of nuclear safety. Because of the geometrical complexity of a pipe and an inaccessibility due to a high radiation, it is difficult to inspect it by the conventional ultrasonic methods. The guided ultrasonic method can be useful for the inspection of a pipe in those harsh environments. Based on the analysis of the dispersion curves for a pipe, a torsional vibration mode, T(0,1) was selected for the detection of cracks. The T(0,1) mode has many advantages, such as a higher sensitivity for a crack from the viewpoint of its non-dispersion characteristics and its wave structure. The torsional mode can be generated by using either an array of electromagnetic acoustic transducers (EMATs) technique or a magnetostrictive sensor technique. The detectability of the cracks was estimated through a series of experiments with artificial notches on a pipe.

Guided Waves as an Online Monitoring Technology for Long-Term Operation in Nuclear Power Plants: Experimental Results on a Steam Discharge Pipe

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Francesco Bertoncini ◽  
Marco Raugi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Complex Structure ◽  
Theoretical Background ◽  
Guided Wave ◽  
Experimental Results ◽  
Term Operation

Guided wave (GW) testing is regularly used for finding defect locations through long-range screening using low-frequency waves (from 5 to 250 kHz). By using magnetostrictive sensors, some issues, which usually limit the application to nuclear power plants (NPPs), can be fixed. The authors have already shown the basic theoretical background and simulation results concerning a real steel pipe, used for steam discharge, with a complex structure. On the basis of such theoretical framework, a new campaign has been designed and developed on the same pipe, and the obtained experimental results are now here presented as a useful benchmark for the application of GWs as nondestructive techniques. Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPPs components.

Development of On-Line Health Monitoring System for Pipes in Nuclear Power Plants

2006 ◽  
Vol 321-323 ◽  
pp. 441-444
Author(s):  
Heung Seop Eom ◽  
Sa Hoe Lim ◽  
Jae Hee Kim ◽  
Young H. Kim ◽  
Hak Joon Kim ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Guided Wave ◽  
Wave System ◽  
Ultrasonic Guided Wave ◽  
On Line ◽  
Series Of Experiments

This study was aimed at developing an effective method and a system for on-line health monitoring of pipes in nuclear power plants by using ultrasonic guided waves. For this purpose we developed a multi-channel ultrasonic guided wave system for a long-range inspection of pipes and a few techniques which can effectively find defects in pipes. To validate the developed system we performed a series of experiments and analyzed the results.

Advanced Signal Processing Techniques for Guided Wave Corrosion Monitoring System in Secondary Circuits of Nuclear Power Plants

2018 ◽  
Author(s):  
Andrei Gribok ◽  
Vivek Agarwal
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Signal To Noise Ratio ◽  
Guided Wave ◽  
Detection Sensitivity ◽  
Complex Geometries ◽  
Corrosion Monitoring ◽  
Coherent Noise ◽  
Induced Defects

This paper describes the application of independent component analysis (ICA) to detect corrosion-induced defects in commercial nuclear power plants. This paper analyzes the applicability and benefits of ICA when applied to guided wave (GW) technology to detect corrosion in secondary circuits, as well as studying the potential for expanding the range of GW technology to include complex geometries and piping components. The ultrasonic GWs can inspect long stretches of straight piping; however, more complex geometries that include elbows, welds, and tees are causing spurious reflections and coherent noise, which significantly decreases the sensitivity of the GW systems. The potential of ICA to improve detection sensitivity is analyzed and practical recommendations are provided. It is demonstrated on GW data collected at one of the commercial nuclear power plants that ICA, under certain conditions, is capable of separating different coherent noise components and has potential for improving signal-to-noise ratio.

Domesticating modernity: the Electrical Association for Women, 1924–86

1999 ◽  
Vol 32 (1) ◽  
pp. 47-67 ◽  
Author(s):  
CARROLL PURSELL
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Well Being ◽  
Point Of View ◽  
Early Years ◽  
Electrical Industry ◽  
Modern Vision ◽  
Religious Zeal ◽  
The One ◽  
British Home

For over half a century, from 1924 to 1986, the Electrical Association for Women (EAW) worked to modernize the British home by bringing the blessings of labour-saving appliances to the aid of British women. Adopting a strategy of facilitation, the EAW sought, on the one hand, to educate women about electricity and its advantages in the home, encourage them to demand greater access to that electricity and keep them abreast of new developments in appliances and the infrastructure (from a national grid to sufficient outlets) necessary for enjoying them. On the other hand, the organization sought to discover the real needs and desires of the women themselves, and to bring this forcibly to the attention of the electrical industry in Great Britain ; to make the ‘women's point of view’, as it was called, a factor in the production, distribution and application of electricity in the home.Although the very masculine electrical industry was a decisive part of both the EAW's context, and of its financial and advisory structure, the group proudly insisted that it was a women's organization in which women addressed other women about women's concerns and well-being. In its early years, the excitement of women coming together in a modern cause was palpable, but as the leadership aged and electricity turned from modern vision to commonplace reality, the almost religious zeal and pace of activities began to falter. A late-hour attempt to highlight nuclear power plants as evidence of a renewed and equally exciting modern moment fell short, and in 1986 the EAW quietly dissolved itself, the casualty of large social changes, some of which it had proudly helped to bring about.

scholarly journals High-Precision Noncontact Guided Wave Tomographic Imaging of Plate Structures Using a DHB Algorithm

2020 ◽  
Vol 10 (12) ◽  
pp. 4360
Author(s):  
Junpil Park ◽  
Jaesun Lee ◽  
Zong Le ◽  
Younho Cho
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Detection Efficiency ◽  
Detection System ◽  
Automatic Detection ◽  
Guided Wave ◽  
Direct Access ◽  
Experimental Conditions ◽  
Plate Structures ◽  
Wide Range

The safety diagnostic inspection of large plate structures, such as nuclear power plant containment liner plates and aircraft wings, is an important issue directly related to the safety of life. This research intends to present a more quantitative defect imaging in the structural health monitoring (SHM) technique by using a wide range of diagnostic techniques using guided ultrasound. A noncontact detection system was applied to compensate for such difficulties because direct access inspection is not possible for high-temperature and massive areas such as nuclear power plants and aircraft. Noncontact systems use unstable pulse laser and air-coupled transducers. Automatic detection systems were built to increase inspection speed and precision and the signal was measured. In addition, a new Difference Hilbert Back Projection (DHB) algorithm that can replace the reconstruction algorithm for the probabilistic inspection of damage (RAPID) algorithm used for imaging defects has been successfully applied to quantitative imaging of plate structure defects. Using an automatic detection system, the precision and detection efficiency of data collection has been greatly improved, and the same results can be obtained by reducing errors in experimental conditions that can occur in repeated experiments. Defects were made in two specimens, and comparative analysis was performed to see if each algorithm can quantitatively represent defects in multiple defects. The new DHB algorithm presented the possibility of observing and predicting the growth direction of defects through the continuous monitoring system.

Application of Laser-Generated Ultrasound for Evaluation of Thickness Reduction in Carbon Steel Pipes

2006 ◽  
Vol 321-323 ◽  
pp. 743-746 ◽  
Author(s):  
Jong Ho Park ◽  
Joon Hyun Lee ◽  
Gyeong Chul Seo ◽  
Sang Woo Choi
Keyword(s):  
Carbon Steel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Wave ◽  
Thickness Reduction ◽  
Steel Pipes ◽  
Time Frequency ◽  
Wall Thinning ◽  
Local Wall Thinning

In carbon steel pipes of nuclear power plants, local wall thinning may result from erosion-corrosion or flow-accelerated corrosion(FAC) damage. Local wall thinning is one of the major causes for the structural fracture of these pipes. Therefore, assessment of local wall thinning due to corrosion is an important issue in nondestructive evaluation for the integrity of nuclear power plants. In this study, laser-generated ultrasound technique was employed to evaluate local wall thinning due to corrosion. Guided waves were generated in the thermoelastic regime using a Q-switched pulsed Nd:YAG laser with a linear slit array. . In this paper, time-frequency analysis of ultrasonic waveforms using wavelet transform allowed the identification of generated guided wave modes by comparison with the theoretical dispersion curves. Modes conversion and group velocity were employed to detect thickness reduction.

Damage Imaging of Pipes in Nuclear Power Plants Using Torsional Guided Wave Modes

2013 ◽  
Vol 577-578 ◽  
pp. 661-664
Author(s):  
Zhao Xiang Wei ◽  
Hong Xu ◽  
Hong Yuan Li
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Guided Waves ◽  
Axial Position ◽  
Imaging Method ◽  
Long Distance ◽  
Torsional Mode ◽  
Damage Imaging

Ultrasonic guided waves can propagate a long distance in pipeline with little attenuation. This means the damage in nuclear power plant can be detected from a remote single position. In the paper, the propagation of the guided waves are analyzed for the nuclear power plant pipes, and the axisymmetric torsional mode T(0,1) is chosen as the detection mode. An imaging method based on the synthetic focusing algorithm is used to obtain the damage information. The method is then verified by the finite element model. Results illustrate that the damage can be detected and located accurately by the damage imaging method. Not only the axial position, but also the circumferential position can be located simultaneously.

An Aging Simulation Model for the Emergency Diesel Generators of Angra 2 by Supplementary Variables

2008 ◽  
Author(s):  
Iona´ Maghali Santos de Oliveira ◽  
Paulo Fernando Ferreira Frutuoso e Melo ◽  
Marcos Oliveira de Pinho
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Point Of View ◽  
Failure Rates ◽  
Aging Effects ◽  
Supplementary Variables ◽  
Technical Specifications ◽  
Diesel Generators ◽  
Markovian Approach ◽  
Useful Lifetime

The extension of the useful lifetime of nuclear power plants is an issue of great importance and concern. From the reliability point of view, this problem requires the consideration of time-dependent failure rates and possible failure dependencies. This analysis has been typically performed through a Markovian approach. To illustrate this point, we have developed a computerized reliability analysis of the emergency diesel generators (EDGs) of a four “loop” PWR plant, considering the hypothesis of aging and perfect repair by using Supplementary Variables to cast the initially Nonmarkovian model into a Markovian one. In order to perform such analysis and to simulate aging effects, a nuclear plant has been taken for reference, which has been commercially operating for only six years. Failure rates were obtained from similar EDGs of another plant, already under aging, while repair data were taken from its technical specifications. Discontinuous repair rates were considered in order to improve maintenance strategies. Several ages were attributed to these equipments, allowing the calculus of the failure probability as well as their availability according to each regarded age. In this sense, the EDGs behavior as to aging can be obtained in detail and decisions concerning maintenance and useful lifetime extension can be made on a stronger basis. To get the desired results in terms of reliability figures and due to the discontinuous repair rates that had to be taken into account, a new numerical method that uses a part of the analytical solution, called Euler Iterative + Characteristic, has been developed in order to solve the differential equations systems, making the solving of the system faster and more efficient.

Guided Waves in Pitch-Catch Configuration: A Theoretical Framework to Steer Toward Experimental Tests

2020 ◽  
Author(s):  
Francesco Cordella ◽  
Mauro Cappelli ◽  
Francesco Bertoncini
Keyword(s):  
Theoretical Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Oil And Gas ◽  
Theoretical Background ◽  
Guided Wave ◽  
Nuclear Industry ◽  
Discharge Pipe

Abstract Guided waves testing allows a long-range screening in pipes of different types and represents an effective and powerful non-destructing technique for defect detections using a limited number of points of measures. This kind of testing hence represents an appealing technique not only for the Oil and Gas industries but also for the Nuclear Industry, in particular regarding the Structural Health Monitoring of Nuclear Power Plants components. Another point of strength of this technique is that it can be applied in different configurations as the pulse-echo (the same probe is used both for transmission and signal receiving) or the pitch-catch (two symmetric probes are used one for the signal transmission and the second one for the signal receiving). In this way, the guided wave testing with magnetostrictive sensors can be reliably used for the short and long-term monitoring of Nuclear Power Plants components. The objective of this paper is to establish a strong theoretical background to pave the way for a robust experimental investigation. In particular, after the characterization through a general theoretical analysis, the focus is on a real steam discharge pipe with a high mechanical complexity used for many years in a research facility and now dismissed. The experimental method applied is the pitch-catch configuration of two magnetostrictive sensors. Preliminary experimental results conducted on a real complex steam discharge pipe are consistent with the theoretical analysis.

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