１．はじめに本解説記事は、（独）原子力安全基盤機構から日本保全学会が委託された課題「保全方式の妥当性に関する調査・検討」を受けて発足した「原子力発電所の保全方式の妥当性に関する調査・検討委員会」において平成18年2月～5月の期間に開催した2回の委員会、4回のワーキンググループ、および7回の幹事会での調査・検討の成果としての報告書を元に、その内容を要約したものである。献身的にご貢献頂きました皆様には心よりの感謝を申し上げます。２．保全方式の種類　原子力発電所を含む大型プラントにおいて採用されている保全方式と......

Che draft guideline for managing the leakage from seal portions of equipment in nuclear power plant has be en eveloped by the special research committee of Japan society of maintenology (ISM). In this paper, the o utline f this guideline is shown and the technical backgrounds and key points including leak management pr ocess, leak ate measurement methods, leak rate prediction method, acceptance criteria, etc. are discussed....
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Development of a Guideline for managing Leakage from Seal Portions of Equipment in Nuclear Power Plants

In order to quantitatively evaluate the ability of a nuclear plant to recover its safety functions, we are developing a method to simulate accident management in chronological order according to an accident scenario, rather than simply evaluating the probability, and to evaluate whether or not a major accident will eventually occur, i.e., whether or not the minimum necessary safety functions can be recovered within a time limit. In this presentation, we will discuss the development of a method to evaluate w...
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Visualizing method for resilience of nuclear power plant

Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation , beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axia l coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@lm is going to be achi eved. Length of the accelerating tube is reduced to less than 25 cm. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of t...
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Study on Portable X-band 950keV linac X-ray Sourcefor On-site Nondestructive Inspection

Tracking human motion from video sequences is a notable technique that is used to detect anomalies in individual human behavior. Several commercially available motion capture devices are based on the use of depth cameras. However, there are a couple of problems with the use of a depth camera. Firstly, a complicated camera system is required, and secondly, the optical field of view is limited. To overcome these problems, we need a technique that can recognize human motion from wide-angle images. In this stud...
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Development of Robust Keypoint Detector for Distorted Wide-Angle Images and Application to Human Motion Analysis

After Fukushima accident in 2011, demand in a design and management to predict severe accidents like Fukushima accident have been realized. To realize them, we must clarify fracture event of reactor pressure v essels or containment vessels. However, the mechanism of failure of structure under severe condition like overpressure or hyperthermia is not clear completely. If we can to predict damage or failure causing se vere accidents in advance by some method, we can take some measures retaining soundness of ...
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Image analysis for the deformation of a specimen with tensile loading

In this research, a new method was developed to identify the “hand behavior” of malicious sabotage behaviors. The Convolutional Neural Network (CNN) and the Long Short Term Memory (LSTM) were applied for analysis of the time-series data of hand behavior images and identification of hand behavior....
英字タイトル:
Development of Sabotage Behavior Detection by Hand Image Analysis and Machine Learning

Condition-based maintenance (CBM) technology is required to perform maintenance on rotating machinery at the optimal time before deterioration and failure occurs. In this study, we describe a deep neural network (DNN) model and corresponding training method for analyzing vibration data to realize CBM for rotating machinery. To apply DNN models in order to analyze time-series data such as vibration data, we first need to optimize the parameters of the models by training them on a dataset consisting of data a...
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Deep Neural Networks for Vibration Signal Analysis and Its Application for Bearing Fault Classification

Under the influence of the F1 accident, there is a growing threat to nuclear security. Among the nuclear security threat, current sensing technique is not effective to sabotage by an insider. In this research, for the purpose of detection of dangerous behavior, dealing with the time-series data. The analysis of the data using PCA(Principal Component Analysis) and SBM(Similarity Based Modeling), was determined for several types of motion....
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Development of malicious behavior detection method by using time-series data

Sabotage by malicious insider is one of significant and serious threats for nuclear security of nuclear power plants. It is difficult, however, to distinguish abnormal behaviors from normal works such as their daily maintenance activities. In this study, a technique was proposed to subdivide the abnormal behavior due to sabotage by image analysis and then to detect and identify the abnormal behavior in real time. ...
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Proposal of Insider Detection Method for Nuclear Security