The four-dimensional (realtime three-dimensional) phased array ultrasonic testing system has been developed. The system enables realtime ultrasonic inspections using three-dimensional (3D) images as opposed to two-dimensional images obtained by the conventional phased array methods. In the system, objects are scanned volumetrica lly with focused beams generated by a matrix array probe and the results are displayed as 3D images in realtime through the conversion from measured data into voxel data using par...
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Four-Dimensional (Realtime Three-Dimensional) Phased Array Ultrasonic Testing

For the safety improvement of a nuclear power plant, safety equipments are constructing additionally under new regulatory requirements. With the increase of safety equipments, it is important to maintain and improve reliability of equipments by inspection. To improve reliability of equipments, we developed a diagnostic system for steam turbine. This system consists of statistical model and physical model. Wih the statistical model, it is possible to detect abnormality from plant operation data and estimate ...
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Diagnostic system for steam turbine using plant operation data

We have been developing ultrasonic testing techniques for acoustical anisotropic media. In this study, we have applied the phased array method using a matrix array transducer to directionally-solidified austenitic steels, i.e. homogeneous anisotropic media, as a first step. Behavior of ultrasonic wave propagation in anisotropic media was analyzed by means of point-source modeling and ray tracing. Insonification angle was optimized in consideration of beam divergence effect based on results of the point...
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Development of Ultrasonic Inspection Techniques using a Matrix Array Transducer for Acoustical Anisotropic Media

The three-dimensional phased-array (3D-PA) ultrasonic technique has been applied to a stress corrosion cracking (SCC) in base metal, and its results for sizing have been quantitatively evaluated. The 3D-PA allows operators to scan objects volumetrically and to display results as 3D images facilitating evaluation processes considerably. The scanning pattern used is called the moving rotational sectorial-scan (MRS-scan) and it is composed of many sectors of different azimuth angles as moving the probe li...
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Visualization and Quantitative Research of Stress Corrosion Cracking Using the Three-Dimensional Phased Array Ultrasonic Technique

We have developed a method using mobile devices to identify plant equipments, especially for repair. After the accident of March 2011 at Fukushima, many nuclear plant operations have still been downed and it leads to the insufficiency of mature experience. The work assistance with IT is getting required under this situation. The IT device can provide appropriate information, e.g. operating instructions, to workers depending on the situation. In order to recognize the current location the arrangement informa...
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Development of Identification Method of Equipments for Repair in Nuclear Plant

This paper describes localization and cable handling me thod as the underlying techniques for underwater surveyrobot. Map matching method comparing cross-sectional hape data cut from a 3-D CAD with structural shapesmeasured by a range sensor is proposed as the localiza tion. The cable handling system mounted to a robot isdeveloped to operate the cable remotely. Some experime nts to evaluate performance of the proposed techniqueswere implemented at mock-ups of a reactor building and he real field. As a resu...
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Development of underlying techniques for underwater survey robot to decommission nuclear power plants

Ultrasonic Integrity of anchor bolts of nuclear power plants is evaluated using test bolts with 1.6mm and 3.2 mm EDM notches. All notches are detected by the following three ultrasonic testing methods: longitudinal normal beam method, hased array (sectorial scanning) method and 3-dimensional phased array method. It is effective in detection of notches to use visual images obtained by ultrasonic phased array m ethods. Additionally, 3D phased array technique can provide fast und wide evaluation of integrity ...
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Ultrasonic integrity evaluation of Anchor Bolts of Nuclear Power Plants

As nuclear power plants age, the importance of maintenance increases and there is a need to apply inspection technologies suitable to importance of each item of equipment. In boiling water reactors, advanced inspection technologies are expected for internal components, i.e. shroud supports with complex-shaped Ni-based alloy welds. As an inspection technology for field inspection of the shroud supports phased array technology has been mainly developed for sizing of Stress Corrosion Crackings accessed from ...
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Ultrasonic testing techniques for inspection of BWR internal components welds.

For safety and early decommissioning of Fukushima, internal survey techniques have been expected to gain an understanding of the state of Fukushima Dai-ichi Nuclear Power Station. Underwater operation and survey is considered to be necessary for vessels and buildings partially filled with retained water. As a complementary of optical instrumentation, ultrasonic underwater visualization techniques have been important for recognizing environment and obstacles for supporting remote operation. In this stud...
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Development of visualization techniques for underwater environment using ultrasonic array sensors: shape measurement

A pipe-wall thinning measurement is one of key inspections to ensure the integrity of the piping system in power plants. Since the pipes of the power plants are covered with insulation, the removal of the insulation, which is time-consuming process in general, is required for the pipe-wall thinning inspection. We have been developing an innovative measurement technology, which enable the pipe-wall thinning inspection without removing the insulation, based on the non-contact ultrasonic sensor proposed by ...
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Feasibility study of non-contact ultrasonic sensor for pipe-wall thinning inspection of power plants