Sensors

Editorial

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3 pages, 169 KiB

Open AccessEditorial

Sensors for Ultrasonic Nondestructive Testing (NDT) in Harsh Environments

by Anthony N. Sinclair and Robert Malkin

Sensors 2020, 20(2), 456; https://doi.org/10.3390/s20020456 - 14 Jan 2020

Cited by 11 | Viewed by 3919

Abstract

In this special issue of Sensors, seven peer-reviewed manuscripts appear on the topic of ultrasonic transducer design and operation in harsh environments: elevated temperature, high gamma and neutron fields, or the presence of chemically aggressive species. Motivations for these research and development [...] Read more.

In this special issue of Sensors, seven peer-reviewed manuscripts appear on the topic of ultrasonic transducer design and operation in harsh environments: elevated temperature, high gamma and neutron fields, or the presence of chemically aggressive species. Motivations for these research and development projects are strongly focused on nuclear power plant inspections (particularly liquid-sodium cooled reactors), and nondestructive testing of high-temperature piping installations. It is anticipated that we may eventually see extensive use of permanently mounted robust transducers for in-service monitoring of petrochemical plants and power generations stations; quality control in manufacturing plants; and primary and secondary process monitoring in the fabrication of engineering materials. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

Research

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16 pages, 4620 KiB

Open AccessArticle

Development of Ultrasonic Guided Wave Transducer for Monitoring of High Temperature Pipelines

by Anurag Dhutti, Saiful Asmin Tumin, Wamadeva Balachandran, Jamil Kanfoud and Tat-Hean Gan

Sensors 2019, 19(24), 5443; https://doi.org/10.3390/s19245443 - 10 Dec 2019

Cited by 17 | Viewed by 4442

Abstract

High-temperature (HT) ultrasonic transducers are of increasing interest for structural health monitoring (SHM) of structures operating in harsh environments. This article focuses on the development of an HT piezoelectric wafer active sensor (HT-PWAS) for SHM of HT pipelines using ultrasonic guided waves. The [...] Read more.

High-temperature (HT) ultrasonic transducers are of increasing interest for structural health monitoring (SHM) of structures operating in harsh environments. This article focuses on the development of an HT piezoelectric wafer active sensor (HT-PWAS) for SHM of HT pipelines using ultrasonic guided waves. The PWAS was fabricated using Y-cut gallium phosphate (GaPO₄) to produce a torsional guided wave mode on pipes operating at temperatures up to 600 °C. A number of confidence-building tests on the PWAS were carried out. HT electromechanical impedance (EMI) spectroscopy was performed to characterise piezoelectric properties at elevated temperatures and over long periods of time (>1000 h). Laser Doppler vibrometry (LDV) was used to verify the modes of vibration. A finite element model of GaPO₄ PWAS was developed to model the electromechanical behaviour of the PWAS and the effect of increasing temperatures, and it was validated using EMI and LDV experimental data. This study demonstrates the application of GaPO₄ for guided-wave SHM of pipelines and presents a model that can be used to evaluate different transducer designs for HT applications. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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12 pages, 2172 KiB

Open AccessArticle

Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications

by Neelesh Bhadwal, Mina Torabi Milani, Thomas Coyle and Anthony Sinclair

Sensors 2019, 19(24), 5383; https://doi.org/10.3390/s19245383 - 6 Dec 2019

Cited by 18 | Viewed by 6144

Abstract

The viability for dry coupling of piezoelectric ultrasonic transducer components was investigated, using a thin foil of annealed silver as a filler material/coupling agent at each component interface. Criteria used for room temperature evaluation were centered on signal-to-noise ratio (SNR) and echo bandwidth, [...] Read more.

The viability for dry coupling of piezoelectric ultrasonic transducer components was investigated, using a thin foil of annealed silver as a filler material/coupling agent at each component interface. Criteria used for room temperature evaluation were centered on signal-to-noise ratio (SNR) and echo bandwidth, for a Li-Nb based transducer operating in pulse-echo mode. A normal clamping stress of only 25 MPa, applied repeatedly over three loading cycles on a precisely-aligned transducer stack, was sufficient to yield backwall echoes with a SNR greater than 25 dB, and a 3 dB bandwidth of approximately 65%. This compares to a SNR of 32 dB and a 3 dB bandwidth of 65%, achievable when all transducer interfaces were coupled with ultrasonic gel. The respective roles of a soft filler material, alignment of transducer components, cyclic clamping, component roughness, and component flatness were evaluated in achieving this high efficiency dry coupling, with transducer clamping forces far lower than previously reported. Preliminary high temperature tests indicate that this coupling method is suitable for high temperature and achieves signal quality comparable to that at room temperature with ultrasonic gel. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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13 pages, 7069 KiB

Open AccessArticle

Design of a Phased Array EMAT for Inspection Applications in Liquid Sodium

by Laura Pucci, Raphaële Raillon, Laura Taupin and François Baqué

Sensors 2019, 19(20), 4460; https://doi.org/10.3390/s19204460 - 15 Oct 2019

Cited by 10 | Viewed by 3904

Abstract

This article describes the development of a French CEA in-house phased array Electro Magnetic Acoustic Transducer (EMAT) adapted to hot and opaque sodium environment for in-service inspection of Sodium Fast Reactors. The work presented herein aimed at improving in-service inspection techniques for the [...] Read more.

This article describes the development of a French CEA in-house phased array Electro Magnetic Acoustic Transducer (EMAT) adapted to hot and opaque sodium environment for in-service inspection of Sodium Fast Reactors. The work presented herein aimed at improving in-service inspection techniques for the ASTRID reactor project. The design process of the phased array EMAT is explained and followed by a review of laboratory experimental test results. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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13 pages, 3712 KiB

Open AccessArticle

2D Ultrasonic Antenna System for Imaging in Liquid Sodium

by Léonard Le Jeune, Raphaële Raillon, Gwénaël Toullelan, François Baqué and Laura Taupin

Sensors 2019, 19(19), 4334; https://doi.org/10.3390/s19194334 - 8 Oct 2019

Cited by 4 | Viewed by 3217

Abstract

Ultrasonic techniques are developed at CEA (French Alternative Energies and Nuclear Energy Commission) for in-service inspection of sodium-cooled reactors (SFRs). Among them, an ultrasound imaging system made up of two orthogonal antennas and originally based on an underwater imaging system is studied for [...] Read more.

Ultrasonic techniques are developed at CEA (French Alternative Energies and Nuclear Energy Commission) for in-service inspection of sodium-cooled reactors (SFRs). Among them, an ultrasound imaging system made up of two orthogonal antennas and originally based on an underwater imaging system is studied for long-distance vision in the liquid sodium of the reactor’s primary circuit. After a description of the imaging principle of this system, some results of a simulation study performed with the software CIVA in order to optimize the antenna parameters are presented. Then, experimental measurements carried out in a water tank illustrate the system capabilities. Finally, the limitations of the imaging performances and the ongoing search of solutions to address them are discussed. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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13 pages, 4833 KiB

Open AccessArticle

Ultrasonic Transducer for Non-Destructive Testing of Structures Immersed in Liquid Sodium at 200 °C

by Jean-François Saillant, Régis Marlier, Frédéric Navacchia and François Baqué

Sensors 2019, 19(19), 4156; https://doi.org/10.3390/s19194156 - 25 Sep 2019

Cited by 9 | Viewed by 5190

Abstract

TUCSS transducer (French acronym standing for Transducteur Ultrasonore pour CND Sous Sodium) is designed for performing NDT (Non-Destructive Testing) under liquid sodium. Under sodium, the tests results obtained show that these transducers have sufficiently good acoustic properties to perform basic NDT of a [...] Read more.

TUCSS transducer (French acronym standing for Transducteur Ultrasonore pour CND Sous Sodium) is designed for performing NDT (Non-Destructive Testing) under liquid sodium. Under sodium, the tests results obtained show that these transducers have sufficiently good acoustic properties to perform basic NDT of a structure immersed under liquid sodium at about 200 °C using conventional immersion ultrasonic technics. Artificial defects were made next to an X-shaped weld and could clearly be detected. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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Review

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20 pages, 8648 KiB

Open AccessReview

State-of-the-Art and Practical Guide to Ultrasonic Transducers for Harsh Environments Including Temperatures above 2120 °F (1000 °C) and Neutron Flux above 10¹³ n/cm²

by Bernhard R. Tittmann, Caio F.G. Batista, Yamankumar P. Trivedi, Clifford J. Lissenden III and Brian T. Reinhardt

Sensors 2019, 19(21), 4755; https://doi.org/10.3390/s19214755 - 1 Nov 2019

Cited by 26 | Viewed by 4507

Abstract

In field applications currently used for health monitoring and nondestructive testing, ultrasonic transducers primarily employ PZT5-H as the piezoelectric element for ultrasound transmission and detection. This material has a Curie–Weiss temperature that limits its use to about 210 °C. Some industrial applications require [...] Read more.

In field applications currently used for health monitoring and nondestructive testing, ultrasonic transducers primarily employ PZT5-H as the piezoelectric element for ultrasound transmission and detection. This material has a Curie–Weiss temperature that limits its use to about 210 °C. Some industrial applications require much higher temperatures, i.e., 1000–1200 °C and possible nuclear radiation up to 10²⁰ n/cm² when performance is required in a reactor environment. The goal of this paper is the survey and review of piezoelectric elements for use in harsh environments for the ultimate purpose for structural health monitoring (SHM), non-destructive evaluation (NDE) and material characterization (NDMC). The survey comprises the following categories: 1. High-temperature applications with single crystals, thick-film ceramics, and composite ceramics, 2. Radiation-tolerant materials, and 3. Spray-on transducers for harsh-environment applications. In each category the known characteristics are listed, and examples are given of performance in harsh environments. Highlighting some examples, the performance of single-crystal lithium niobate wafers is demonstrated up to 1100 °C. The wafers with the C-direction normal to the wafer plane were mounted on steel cylinders with high-temperature Sauereisen and silver paste wire mountings and tested in air. In another example, the practical use in harsh radiation environments aluminum nitride (AlN) was found to be a good candidate operating well in two different nuclear reactors. The radiation hardness of AlN was evident from the unaltered piezoelectric coefficient after a fast and thermal neutron exposure in a nuclear reactor core (thermal flux = 2.12 × 10¹³ ncm⁻²; fast flux 2 (>1.0 MeV) = 4.05 × 10¹³ ncm⁻²; gamma dose rate: 1 × 10⁹ r/h; temperature: 400–500 °C). Additionally, some of the high-temperature transducers are shown to be capable of mounting without requiring coupling material. Pulse-echo signal amplitudes (peak-to-peak) for the first two reflections as a function of the temperature for lithium niobate thick-film, spray-on transducers were observed to temperatures of about 900 °C. Guided-wave send-and-receive operation in the 2–4 MHz range was demonstrated on 2–3 mm thick Aluminum (6061) structures for possible field deployable applications where standard ultrasonic coupling media do not survive because of the harsh environment. This approach would benefit steam generators and steam pipes where temperatures are above 210 °C. In summary, there are several promising approaches to ultrasonic transducers for harsh environments and this paper presents a survey based on literature searches and in-house laboratory observations. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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Other

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15 pages, 5214 KiB

Open AccessTechnical Note

Pb(Mg_1/3Nb_2/3)-PbTiO₃-Based Ultrasonic Transducer for Detecting Infiltrated Water in Pressurized Water Reactor Fuel Rods

by Geonwoo Kim, Namkyoung Choi, Yong-Il Kim and Ki-Bok Kim

Sensors 2019, 19(12), 2662; https://doi.org/10.3390/s19122662 - 13 Jun 2019

Cited by 4 | Viewed by 3388

Abstract

In this study, a high-sensitivity Pb(

{Mg}_{1 / 3} {Nb}_{2 / 3}

)

O_{3} {- PbTiO}_{3}

(PMN-PT)-based ultrasonic transducer was developed for detecting defective pressurized water reactor (PWR) fuel rods. To apply the PMN-PT substance to nuclear power plant [...] Read more.

In this study, a high-sensitivity Pb(

{Mg}_{1 / 3} {Nb}_{2 / 3}

)

O_{3} {- PbTiO}_{3}

(PMN-PT)-based ultrasonic transducer was developed for detecting defective pressurized water reactor (PWR) fuel rods. To apply the PMN-PT substance to nuclear power plant facilities, given the need to guarantee their robustness against radioactive materials, the effects of neutron irradiation on PMN-PT were investigated. As a result, the major piezo-electric constants of PMN-PT, such as the electrical impedance, dielectric constant, and piezo-electric charge constant, were found to vary within acceptable ranges. This means that the PMN-PT could be used as the piezo-electric material in the ultrasonic transducer for nuclear power plants. The newly developed ultrasonic transducer was simulated using a modified KLM model for the through-transmission method and fabricated under the same conditions as in the simulation. The through-transmitted waveforms of normal and defective PWR fuel rods were obtained and compared with simulated results in the time and frequency domains. The response waveforms of the newly developed ultrasonic transducer for pressurized water reactor (PWR) fuel rods showed good agreement with the simulation outcome and could clearly detect defective specimens with high sensitivity. Full article

(This article belongs to the Special Issue Sensors for Ultrasonic NDT in Harsh Environments)

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