Industry development activities on applied laser research held at Fukui branch of Japan Atomic Energy Agency are reported. Industry development is inevitable in long-term vision and strategy for developing maintenance technology and establishing decommissioning technology. Fukui branch of JAEA has organized public seminar offering businesses to promote these activities and technology exchange for years. Here some examples offered in the current seminar are introduced concerning with laser technology. Fin...
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Industry Development Activities and Applied Laser Research Activities at Fukui Branch of Japan Atomic Energy Agency

The aim of this work presented here is to investigate the applicability of the guided wave testing to detect and evaluate the quality of laser beam butt welding line. First, four test pipes were prepared. All of the pipes were laser beam butt welded from inside of the pipe using laser torch. Two pipes of them were high-quality welded, the others were low-quality. Two different pipe-wall-thicknesses were in each quality. Secondly, Laser beam butt welding line detection and the quality evaluation experim...
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EMAT-Guided Wave Approach for Detecting and Quality Evaluation of the Laser Beam Butt Welding Line on the Inner Surface of the Steel Pipe

A thermal-resistant fiber Bragg grating (FBG) fabricated by femtosecond laser processing was examined to evaluate the performance as a strain sensor, compared with a conventional FBG se nsor. Each FBG was affixed on a stainless-steel beam along with a strain gauge to measure the Bragg wavelength shift as a function of strain. We used the intensity of the reflection spe ctra from the FBGs as a weighting factor to determine the Bragg wavelengths. Although the strain sensitivity for the thermal-resistant FBG ...
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Development of a health monitoring system using a thermal-resistant fiber Bragg grating for fast reactor power plants: performance evaluation of a thermal-resistant FBG for strain measurement

A composite-type optical fiberscope was combined with a laser processing head to repair heat exchange pipes of Fast Breeder Reactor (FBR). The head can rotate axially and move back and forth longitudinally in the 1-inch pipes. The property of fiberscope and the motion of the head can successfully observe the pipe’s inner surface to find the cracks which should be repaired by laser welding. The project, which aims for developing the integrated system of inspection and repair, proposes an effective cost...
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Development of a Laser Processing Head Using a Composite-type Optical Fiberscope to Inspect and Repair 1-inch Heat Exchanger Pipes

Fiber Bragg Grating (FBG) is the periodic refractive-index structure in an optical fiber core, where the light of a specific wavelength is reflected. It can be used as te mperature or a distorted sensor by measuring change of the reflective wavelength of FBG. We processed FBG using a Chirped Pulse Amplification titanium sapphire laser. As a result, the peak intensity of reflective spectrum has been successfully improved from -40 dB to -24 dB. Heating test under operational temperature of Fast Breeder React...
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Fabrication and performance assessment of FBG sensor with pulse laser processing

In Japan there are a lot of aging plants which have wearing parts and wall thinning pipes and require major maintenance and repairs. The efficient method is required to repair all of them in various spaces. A new type of three-dimensional measurement systems based on Conoscopic Holography is steadily gaining ground against older techniques. We measured the shape of the piping inner wall by using the Conoscopic Holography Scope. The laser welding position of the piping inner wall could be confirmed by...
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Development of the tube inner wall inspection technology

Strain sensors, which can be used for integrity monitoring of plant components and piping during the operation period continuously, are effective from the point of view of proac tive maintenance. FBG (Fiber Bragg Grating) sensor is one of the expective sensors and is used in various plants and civil engineering and construction fields except for high te mperature service. In order to apply to the component and piping of fast reactor, heat resistance is an indispensable feature of the sensor. In this study,...
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Development of heat-resistant FBG sensor for high temperature structures monitoring