The purpose of this study is to develop an evaluation method to optimize both cost and risk in maintenance strategy of BWR plant in long-term operation. Plant operation is simulated in a simplified model, and the condition of the components treated in the model are evaluated statistically with Monte Carlo simulation. While Probabilistic Safety Assessment(PSA) methods such as Fault Tree Analy sis(FTA), Event Tree Analysis(ETA), and Failure Mode and Effects Analysis(FMEA) are also used to estimate Core Damag...
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Development of an Evaluation Method for Cost and Risk in Maintenance Strategy of BWR

RF tags that are implemented RFID technology as tag has been used in various fields. Tags have been developed, such as resistance to chemic als and high temperature resistant RF tags are also used in specialized fields. The RF tag apply to the existing nuclear field, had been co ncerned about the effects of radiation to the RF tags. Now, since the RF tag with a goal to develop radiation-proof, we have examined, such as applying for maintenance of nuclear facilities under radiation environment. We report t...
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Application to the conservation of RF tags in the radiation environment

Abstract The method of text-mining has been applied to accumulated documents on anomaly for nuclear power plant to represent them in systematic way. The twelve event reports from the public database of the nuclear power plant anomalies have been taken as examples. I t has shown that the similarity and singularity of the event can be successfully described in the proposed framework. It has also sh own that the important key words and the contextual structure of the report have been successfully extracted b...
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Effective Use of Trouble Information by Text-mining Method

The framework of intelligent support system for the maintenance of nuclear power plant is proposed in this paper with emphasis on the combined use of a portab le device and intelligent information processing. The purpose of this system is the realization of flexible inspection process and effective diagnosis process to be performed on-site with the aid of the mobile agent capable of performing various tasks moving along the network. The results of the scenario-based and f unction-based evaluation based on ...
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Application of Mobile Agent Technology for Maintenance Support of Nuclear Power Plants

The framework of intelligent support system for the maintenance of nuclear power plant has been osed in our previous study. In this paper, the method of providing information based on the task irement of the mainte nance personnel depending on their expertise and the situation faced. Two 3 of interfaces according to each strategy have been developed and the effectiveness of the osed framework has been evaluated experimentally....
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Maintenance Support according to the Task Requirements

Abstract : A hybrid diagnostic agent system is developed to detect and identify early an anomaly that happens in the fast-breeder reactor “Monju”. The system outputs a diagnostic result by integrating the results of diagnosis by four diagnostic software agents. They are (1) an estimation agent of overall heat transfer coefficient of evaporator and superheater, (2) a state identification agent based on SVM (Support Vector Machine), (3) an anomaly detection agent by WT (Wavelet Transformation), and (4) a...
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Whole System and Estimation Technique of Overall Heat Transfer Coefficient of Evaporator and Superheater

In this study, the generalized failure mechanism knowledge (GFMK) derived from trouble cases in the Rokkasho reprocessing plant has been applied to an mechanical subsystem in the same plant in order to examine its general applicability. This study confirms that the GFMK can be applied to the subsystem of a pool water cooling system and that a potential failure mechanism can be successfully derived. The efficacy of the derived knowledge regarding this failure mechanism was evaluated by referring to maintenan...
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Application of the structured representation of trouble cases in reprocessing plant

A steam tube-leak is a very critical issue in industrial plants because the steam jet from the damaged point immediately causes damage to the surrounding tubes. Therefore, an early detection of the tube leak is important to reduce the maintenance cost and the outage time. In this study, we conducted a detection test of the steam tube leak using acceleration sensors; they are expected to catch a radial tube-vibration induced by acoustic propagation. Through the test, we found that the sensor detected a radia...
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Development of detection method for a steam tube-leak in a boiler using acceleration sensors

The purpose in this research is to verify whether risk recognition can be explained not only by the subjective evaluation methods but also by the objective evaluation based on autonomic nervous activity. In the present study, a fundamental method to realize objective risk recognition evaluation has been proposed using heartbeat data in the safety education at experiential training facilities. Based on the results obtained in this research, it has been confirmed that risk-taking behavior characteristics can ...
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Evaluation of risk sensitivity and risk taking behavior based on objective measurements

Abstract: Outlines of, and the empirical observations from, an action research project aiming at improvement of relationship between nuclear community and the public have been reported in this paper. Ultimate goal of the project is effective reduction of social construct risk of nuclear power plants. As an initial approach to the goal, a proactive information provision scheme has been designed based on the knowledge acquired during our previous attemp t of public communication named repetitive dialogue for...
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Proactive Information Provision for Reducing Social Construct Risk of Nuclear Facility