In order to optimize plant maintenance, it is important to diagnose an integrity of equipment and use it for maintenance planning. We developed the integrity diagnostic method combining statistical model and physical model. The statistical model detects abnormality from process data and estimates abnormal parameters. The physical model estimates failure equipment from abnormal parameters. As a result of test data evaluation, it was confirmed that the proposed method can detect anomalies and estimate faulure...
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Development of integrity diagnosis technique for plant equipment

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 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

Residual stress improvement technologies have been developed and applied to Boiling Water Reactor (BWR) plant components in order to prevent from stress corrosion cracking (SCC) of stainless steel and Ni-based alloy materials. Water Jet Peening (WJP) is one of the effective procedures for residual stress improvement, and has the various advantages for the application to the reactor internal components of the operating nuclear power plants because WJP uses only water for residual stress improvement. As...
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Application of Water Jet Peening to the Shroud Components in BWR Power Plant and Residual Stress Measurement after WJP.

It is well understood that the reduction of the residual tensile stress in the welded zone is effective as inhibitor of occurrence and growth of SCC in low-carbon stainless steel. Therefore, some stress reduction methods for the pipe welded zone have already been developed. However, stress reduction method for small-bore, thin-wall pipes which nominal outside diameter are 60.5mm and below, have not been established. In this study, residual tensile stress reducti on method that is applicable to small-bore p...
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DEVELOPMENT OF STRESS REDUCTION METHODIN THE SMALL-BORE PIPE

After the Great East Japan Earthquake, as for the nuclear power plant, addition and modifying of the facility to operate more safely are pushed forward under the thought of the new regulation standard. After the safety of the nuclear power plant being confirmed, and having operated again, an outage is carried out every 13 months. Efficiency of the inspection work is necessary to end outage during a same period as the past though facilities for safety enhancement are added to subject of inspections. In ...
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Shortening of outage by advancement and the efficiency of the inspection techniques.

We have developed a method using mobile devices to recognize the current location in a plant where radio/marker such as GPS is not available. Depending on the site situation the device can provide appropriate information, e.g. operating instructions, to workers. In order to recognize the current location, we identify surrounding plant equipment and register its location as the current one. The mobile device with 3-D depth acquisition can extract a plurality of pipes, collate its feature amount with the DB, ...
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Development of Location Detection Method in Plant Independent of Wireless Signal and Position Marker Identification

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

A pipe-wall thinning measurement is required to ensure integrity of a piping system in a power plant. Aiming to reduce the inspection time of the pipe-wall thinning measurement, we have been developing an innovative measurement technology which enables the pipe-wall thinning inspection without removing the insulation, based on the non-contact ultrasonic sensor proposed by University of Bristol. To apply this technology to the actual plant inspection, the sensor durability needs to be confirmed. In this stud...
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Investigation into applicability of a non-contact ultrasonic sensor to pipe-wall thinning inspection of power plants

A pipe-wall thinning measurement is required to ensure integrity of a piping system in a power plant. Aiming to reduce the inspection time of the pipe-wall thinning measurement, we have been developing an innovative measurement technology which enables the pipe-wall thinning inspection without removing the insulation, based on the non-contact ultrasonic sensor proposed by University of Bristol. To apply this technology to the actual plant inspection, sensor calibration and extension of measurable thickness ...
英字タイトル:
Development of a non-contact ultrasonic sensor for application to pipe-wall thinning inspection in power plants