Phased array ultrasonic testing (PAUT) has performed an important role for plant maintenances. However, many parts of cast austenitic stainless steels are difficult to be inspected by UT owing to their noises from large grains. We have been noticing that depending on the PAUT conditions, (e.g. incident angles and focal depths), the tendency of echoes from defects are different from that of grain noises. Thus we have developed new PAUT system which can analyze the tendency of echoes from comprehensive PA...
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Sizing Accuracy Improvement of Defects in Cast Austenitic Stainless Steel Using Post Processing Phased Array UT

After 2002, Stress Corrosion Cracking (SCC) came to be detected in the low carbon stainless steel PLR Piping of BWR plants. However, it worked on the improvement of ultrasonic examination technology for PLR Piping in Japan BWR Owners Group (JBOG) , because the mistake of the evaluation was caused as a rare case. In this study, it introduces the improvement of ultrasonic testing technology and evaluation....
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Know-How for the Ultrasonic Examination Practice & Evaluation of PLR Piping

Many anchor bolts have been used for fixing many components in nuclear power plant (NPP), securing safety against seismic ev ents. Some methods have been developed to detect crack-like defects in bolts which may occur after seismic events. On the ot her hand, assuming long term use of NPP, a method to detect bolt thinning was thought to be needed. In this study, by using bolt specimens with an artificially grinded portion, a new method to detect thinning and to measure its depth was developed....
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Development of inspection method for thinned bolts by PA-UT

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

Nuclear spent fuel intermediate storage facility is planned to be located in the Sea of Japan coast area. Therefore, there is risk of structure corrosion by sea salt aerosol. This study is the co rrosion risk evaluation and it's countermeasure of that facility....
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Evaluation of Salt Damage Structure Located in the Coastal

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 ...
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Study on availability of laser peening during refueling work- Preventive maintenance to shorten outage period