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...
英字タイトル:
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...
英字タイトル:
Laser-ultrasonic study of micro crack sizing and its application to nuclear reactor internals

Nuclear Regulation Authority has been working on new regulation considering lesson learnt from Fukushima Daiichi accident, state-of-the-art technical knowledge, and trends of regulation in the other countries including safety standards defined by international organization such as IAEA. We, Kyushu EPCO, have also been conducting many different measures considering Fukushima Daiichi accident, and would like to introduce those recent activities. ...
英字タイトル:
Measures to further Improve safety and reliability of Kyushu Electric Power Co.,Inc.

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...
英字タイトル:
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...
英字タイトル:
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...
英字タイトル:
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...
英字タイトル:
Verification and Application of Beam Steering Phased Array UT Technique for Complex Structures

The request of the inspection to reactor internals is increasing with application of the Japanese operation and maintenance code to aged nuclear power plants. Toshiba has developed many outstanding under water inspection t echnologies combined with ultrasonic testing (UT) techniques and remote operated vehicles (ROVs) technologies. Water gap phased array UT technique is capable to apply to all internals including complicated form part such a s reactor bottom head penetration weldment. Laser-ultrasonic te...
英字タイトル:
Inspection Technologies for Reactor Internals of Aged Nuclear Power Plants

Laser peening is a surface enhancement process that introduces compressive residual stress on materials by irradiating laser pulses under aqueous environment. The process utilizes the impulsive effect of high-pressure plasma generated by ablative interaction of each laser pulse. It is very beneficial to shorten ou tage period if laser peening is available during refueling work. It is confirmed that laser peening can be available in the situation by experiment and analys is. This report describes detail of ...
英字タイトル:
Study on availability of laser peening during refueling work- Preventive maintenance to shorten outage period

Toshiba have developed a method of reactor internals replacement and also applied some of methods to improve the residual stress for internals that can't be replaced easily. Ultrasonic shot peening (USP) is a stress improvement method that improves the surface residual stress of heat affected zone by using the vibration of Ultrasonic wave. As th e system of USP is simpler and more compact than the other methods, USP is applicable to welds on the bottom of reactor vessel during reactor internals replacemen...
英字タイトル:
Application of Ultrasonic Shot Peening for Internals of Boiled Water ReactorPower Plants