Additional monitoring is occasionally done on suspicious equipment such as pumps, motors, valves and so on, when monitoring parameters are dif ferent from normal operation in Nuclear Power Plant. To avoid excess radiation exposure during arrangements for the additional monitoring requ iring sensors installation and cables layout, wireless data transmission system is desired. ZigBee system, which uses 2.4GHz radio frequency a nd has repeating function, is suitable for the needs above without influencing on ...
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Study on DATA transmission by 2.4GHz radio frequency in Nuclear Power Plant

An area detector technique has to be applied to the strain scanning method for the coarse grains. A new rotating slit system was designed for a 2-dimensional (2D) detector strain scanning method. The rotating slit system focuses the 2D detector on the center of the goniometer, an d the gauge volume is made by the rotating slit system. The stress measurements were examined by the rotating slit and 2D detector. The measured diffraction spots shifted for the 2D strain scanning. The magnitude of the shift of t...
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Study on Evaluation of Internal Stresses using Area Detector

The on-site residual stress measurement by the conventional XRD method is difficult because of the size of the equipment. For mainly on-site measurement and also u sing in the production line, we have developed the portable x-ray residual stress analyzer which is compact size e and short measurement time. The analyzer is usin cosα method, not sin2psi method which is used for conventional XRD stress measurement, and measure the stress from the complete Debye ring information by single a le X-ray exposure. I...
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For residual stress measurement method using a cosα method by the two-dimensional detector system

In power plant, the operator monitors measured values of many installed sensors for operation and maintenance. Since the number that can be visually confirmed is limited, we have proposed two-stage autoencoder for anomaly detection. The latest version was developed to suppress false positives due to spurious correlations in training data, and its effectiveness was shown using simulation data. In this paper, the anomaly detection performance is shown using the operational data of an actual power plant. As a ...
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Performance Evaluation of the Anomaly Detection by Two-Stage Autoencoder using Power Plant Data

In the ultrasonic testing for periodic inspection of nuclear power plants, it is necessary to decide the inspection condition and probe scanning range before the inspection. Especially, ultrasonic propagation analysis was difficult for complex curved component such as nozzle parts. Therefore, we have developed an ultrasonic propagation simulation technique for three-dimensional complex curved objects based on the definition of curved surface functions and virtual scanner. We can examine appropriate ins...
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Development of Ultrasonic Propagation Simulation Technique for Three-Dimensional Complex Curved Surface Shape

The use of guided Lamb waves in nondestructive testing allows a faster and more sensitive inspection when compared with other ultrasound techniques. The process is not easy to carry on because of the multimodal and dispersive nature of guided Lamb waves. This paper explains all the procedures to image linear defects machined in an aluminum plate in detail. An angle adjustable ultrasonic transducer was used to generate the Lamb guided wave for inspection. The technique is effectively able to determine the po...
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3-D Imaging of Cracks in Metal Plate with Guided Waves Generated by Angle Adjustable Ultrasonic Probe

1.はじめに 東海第二発電所は,1978 年 11 月に運転を開始した電 気出力 110 万 kW の沸騰水型軽水炉(BWR-5)である。 東海第二発電所は定格熱出力一定運転中,東北地方太平 洋沖地震(茨城県東海村での観測震度「6 弱」)により, 平成23年3月11日 14時48分に「タービン軸受振動大(ト リップ設定値 0.25mm 以上)」による主発電機自動停止 (タービン主蒸気止め弁閉)の信号により原子炉が自動 停止した。この地震の影響により,「外部電源喪失」となっ たものの非常用ディーゼル発電機(......

1. 震災概要 女川原子力発電所は宮城県牡鹿半島に位置し、1 号機 から 3 号機の定格電気出力の合計が 2,174MW の発電所 である。 2011 年 3 月 11 日(金)14 時 46 分頃に発生した東 北地方太平洋沖地震(震源地 三陸沖約 130km、深さ約 24km)は、マグニチュード 9.0 という日本国内史上最大 を観測した。女川原子力発電所の立地する宮城県牡鹿郡 た。しかし、この火災は原子炉自体の制御には影響を及 ぼさず、原子炉水位は原子炉隔離時冷却系で、原子炉圧 力は逃がし安全弁で制......

We are developing portable non-destructive testing (NDT) X-ray source with X-band linac and low power magnetron. Now, we start the experiment of electron acceleration and X-ray generation using by 950 keV X-band linac NDT system. The 950 keV X-band linac X-ray generator is under development for corrosion wastage of tubes and condition bas ed maintenance of impeller pumps. However, about 1 MeV X-ray source can be only used for thin tubes of about 20 mm thickness. Therefore, we start to design about 4 MeV X-...
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Development of High Energy X-ray NDT System with 3.95 MeV X-band Linac

The purpose of this study is to investigate environmental effects on low cycle fatigue crack growth of SUS316. Low cycle fatigue test and periodical observation on inner surface of a hollow specimen was conducted by developing new type of replica observation. The crack growth in PWR environment was measured and the investigation of environmental effects on crack initiation and propagation was conducted. Crack initiation rate of fatigue test in PWR environment is faster than in air condition. Crack pr...
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Environmental Effect on Low Cycle Fatigue Crack Growth of SUS316