Stress Corrosion Cracking (SCC) on reactor internal components has become one of the most important issues in recent years, and demand for the inspection of reactor internals is increasing. Especially, SCC has detected in shroud support recently so inspection technology for s hroud support has to be developed as soon as possible. We have developed delivery system for shroud support in BWR plant which is availabl e for Visual Testing and Ultrasonic Testing. The specification and positioning capability of th...
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Development of Delivery System for Shroud Support in BWR Plant

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

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

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

In-Vessel Visual Inspection (IVVI) is usually conducted as indirect visual inspection with remote TV cameras. We often face the following issues in IVVI. When IVVI is conducted at narrow spa ce in the vessel, it is difficult for inspectors to set the cameras to the best position remotely and manually. When the cameras are quickly moved to reduce hours of IVVI, the visibility be comes poor because of motion blurs. For overcoming these problems, we focused on “Super Resolution (SR)” that is one of image proc...
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In-Vessel Visual Inspection System using Super Resolution Technique

A newly developed in-vessel visual inspection (IVVI) device designed to improve the quality of visual inspection in Boiling Water R eactors (BWRs) while providing significant critical path savings during refueling outages. And Super Resolution Visual Testing (VT) system enhances the inspection image resolution. The system assists the examiners under the condition of relatively faster scanning speed and longer work distance. The effectiveness of the time saving was qualified by the resolution testing with V...
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Maintenance and Inspection Technologies for Shorter Outage