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

A feasibility study was conducted on advancement of plant maintenance technology by noticing the integration of non destructive test, fracture mechanics, distributed netw ork, and human interface technologies. In fact, the study was conducted by dividing into the two area: Area A for the methods of non destructive testing and the simulatio n methods on fracture mechanics, while area B for human interface technologies for maintenance work support. During the course of the feasibility study, the developmenta...
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Feasibility Study on Advancement of Maintenance Quality for Nuclear Power Plants

Welding is an essential industrial process in the fabrication of a variety of products and also in maintenance activities. Although most welding processes have already been automated, the high reliability of the manual welding fabrication is still in demand. In this paper the necessity of the in-process monitoring of the performance of manual welders is addressed in order to assess the skill of a manual welder in the workshop environment. The behavior of welders with different skill levels was monitored dur...
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MONITORING AND ANALYSIS OF THE BEHAVIOR OF WELDERS DURING MANUAL WELDING

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

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

狩川 大輔 Daisuke KARIKAWA Abstract The discussions in the committee for investigation of the integrity and safety of the Kas hiwazaki-Kariwa nuclear power plant after earthquake has been analyzed to clarify what is important in the explanation of the technical details. The results imply that the consideration of the unstate d assumptions and the variety of the level of understanding should be carefully taken into account....
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Unstated knowledge required in the communication for describing safety of nuclear power plant

Abstract The purpose of this study is to develop a method for quantitative evaluation of the running cost and safety in a Nuclear Power Plant (NPP). A new model for numerical evaluation is proposed based on the concept where the four issues such as Cost of Electricity (COE), maintenan ce cost, loss by the failures, and several risks are evaluated statistically by using the Monte Carlo simulation. The results show different d ependence on the parameters used in the model. These results would be useful to d...
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Development of quantitative evaluation method for the cost and safetyin maintenance plan of Nuclear Power Plant