A New method for non-destructive testing (NDT) of surface-breaking tight cracks based on laser-induced nce acoustic waves (SAW) is proposed. A Q-switched Nd:YAG laser is used to generate SAW through Live interaction between material and the laser pulses. The SAW is probed by an optical interferometer as a o displacement of the surface. A state-of-the-art technique in laser-ultrasonic NDT is reviewed: that is the < depth measurement by using fr equency analysis of SAW transmitted through cracks. The techni...
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Laser-Ultrasonic Non-Destructive Testing:hniques and Applications in Nuclear Industry

A new method for non-destructive testing（NDT）of surface-breaking tight cracks based on laser-induced surface acoustic waves（SAW）is proposed. A Q-switched Nd:YAG laser is used to generate SAW through ablative interaction between material and laser pulse. The SAW is probed by an optical interferometer as a micro displacement of the surface. A state-of-the-art technique in laser- ultrasonic NDT is developed: that is the crack depth measurement by using frequency analysis of laser-induced SAW transmitted throug...
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Laser-ultrasonic study of micro crack sizing and its application to nuclear reactor internals

In the remote field eddy current testing, we proposed the method of enhancing the magnetic flux density in the vicinity of an exciter coil by controlling the ma gnetic flux direction for increasing the sensitivity of detecting outer defects on a tube and used the flux guide made of a magnetic material for the method. T he optimum structural shape of the flux guide was designed by the magnetic field analysis. On the experiment with the application of the flux guide, the magneti c flux density increased by 5...
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Sensitive Technique for Detecting Outer Defect on Tube with Remote Field Eddy Current Testing

Toshiba has developed laser-based maintenance, inspection and repair technologies as countermeasures against stress corrosion cracking (SCC) in nuclear power reactors. Laser peening (LP) is a novel process for preventive maintenance, which improves residual stress from tensile to compressive on material surface by irradiation laser pulses in water. Laser-ultrasonic testing (LUT) is capable of detecting and sizing SCC having a depth of about 0.5 mm. Underwater laser welding can be fulfilled by making local ...
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Laser based maintenance technologies for PWR power plants

We confirmed the defect detection performance of the eddy current testing (ECT) system in order to inspect the bottom-mounted instrumentation (BMI) nozzle in reactor pressure vessel. We developed the small size cross coil type ECT sensor that has the magnetic cores near the coils and the sensor scanning equipment based on the portable laser peening system. According to the experimental results that measured the sensitivity for the defects on the concave specimen and the relationship between the senso...
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Development of Eddy Current Testing System for Bottom-Mounted Instrumentation Nozzle in Reactor Pressure Vessel

We confirmed the defect detection performance of the eddy current testing (ECT) system in order to inspect the bottom-Mounted instrumentation (BMI) nozzle in reactor pressure vessel. We developed the small size cross coil type ECT sensor that has the magnetic cores near the coils and the sensor driving unit based on the portable laser peening system. According to the experimental result that measured the relationship between the sensor inclined angle and defect detecting sensitivity on the convex surfa...
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Development of Eddy Current Testing System for Bottom-Mounted Instrumentation Nozzle in Reactor Pressure Vessel

Multifunction laser welding head has been developed. The head is able to perform not only underwater laser welding as repair, but also laser peening as preventive maintenance and laser ultrasonic test ing as inspection. For inspection with multifunction laser welding head, a new method of visualized weld defects in water by laser-ultrasonics has developed. To detect and visualize a surface of weld metal with welding bead, the authors have developed a new detection method by leaky wave induced by interactio...
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Development of Multifunction Laser Welding Head (3) - Surface Inspection Technique by Laser-ultrasonics -

山本 智 Satoshi YAMAMOTO Non-Member (Times New Roman 10pt) should be about 150 words. Recently, an application target of the phased array ultrasonic testing (PAUT) has been extended. For the inspection of CASS, low frequency (less than 1 MHz) array probe is required. Low frequency array probe are usually constructed by large pitch element. In the case of linear scanning, the low frequency array probe could not obtain enough number of sound beams which construct a precise B-Scope image owing to non-dense arra...
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Accuracy improvement of the linear scanning phased array UT with a large element array probe

Inspection technique for complex surface profiles has been required in order to ensure the reliable operation and high operating rate of nuclear power plants, because many parts due to inspection have complex geometry. We have developed Pha sed Array (PA) ultrasonic testing with immersion technique which suitable to complex geometry. In this paper, we developed precise inspection technique for curvature surface profile such as a nozzle of pressure vessel. For curved surface pro file, Synthesis Aperture Foc...
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Development of Phased Array Inspection Technique for Nozzle Pipes with Curved Surface

Phased Array Ultrasonic Testing (PAUT) techniques for complex geometries are greatly progressing. We developed an immersion PAUT which is suitable for complex surface profiles such as nozzles and deformed welded areas. Furthermore, we have developed a shape adaptive beam steering technique for 3D complex surface structures with conventional array probe and flexible coupling gel which makes the immersion beam forming technique usable under dry conditions. This system consists of 3 steps. Step1 is surfac...
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Verification and Application of Beam Steering Phased Array UT Technique for Complex Structures